An international team of researchers has discovered that a microRNA produced by certain white blood cells can prevent excessive inflammation in the intestine. The study, “Myeloid-derived miR-223 regulates intestinal inflammation via repression of the NLRP3 inflammasome,” which will be published May 9 in The Journal of Experimental Medicine, shows that synthetic versions of this microRNA can reduce intestinal inflammation in mice and suggests a new therapeutic approach to treating patients with Crohn’s disease or ulcerative colitis.
Inflammatory bowel disease (IBD), including Crohn’s disease and ulcerative colitis, affects almost 2 million people in the US. Although IBD is caused by a complex mix of genetic and environmental factors, it is thought to be initiated by an excessive immune response against bacteria in the gut. This immune response involves the recruitment of various white blood cells, such as neutrophils and monocytes, into the intestine and the activation of a protein complex in these cells known as the inflammasome. The inflammasome, in turn, activates the proinflammatory signaling molecules IL-1β and IL-18, which stimulate the further influx of white blood cells.
MicroRNAs are small RNA molecules that can bind and repress protein-coding messenger RNAs. An international team of researchers led by Eóin McNamee at the University of Colorado-Anschutz Medical Campus found that IBD patients showed increased levels of a microRNA called miR-223 during active bouts of inflammation. This microRNA was also elevated in laboratory mice with colitis.
miR-223 is produced by neutrophils and monocytes and has previously been shown to repress the messenger RNA encoding NLRP3, a key component of the inflammasome. McNamee and colleagues found that mice lacking miR-223 expressed higher levels of NLRP3, causing increased IL-1β production and enhanced susceptibility to intestinal inflammation.
In contrast, mice treated with lipid nanoparticles containing synthetic RNA molecules that mimic miR-223 showed lower levels of NLRP3 and IL-1β and were accordingly protected from experimentally induced colitis.
“Our study highlights the miR-223–NLRP3–IL-1β regulatory circuit as a critical component of intestinal inflammation,” McNamee says. “miR-223 serves to constrain the level of NLRP3 inflammasome activation and provides an early brake that limits excessive inflammation. Genetic or pharmacologic stabilization of miR-223 may hold promise as a future novel therapy for active flares in IBD.”
WHITTIER, Calif. — Lynn Whittaker stood in the hallway of her home looking at the framed photos on the wall. In one, her son, Andrew, is playing high school water polo. In another, he’s holding a trombone.
The images show no hint of his life today: the seizures that leave him temporarily paralyzed, the weakness that makes him fall over, his labored speech, his scrambled thoughts.
Andrew, 28, can no longer feed himself or walk on his own. The past nine years have been a blur of doctor appointments, hospital visits and medical tests that have failed to produce answers.
“You name it, he doesn’t have it,” his mother said.
Andrew has never had a clear diagnosis. He and his family are in a torturous state of suspense, hanging their hopes on every new exam and evaluation.
Recently, they have sought help from the Undiagnosed Diseases Network, a federally funded coalition of universities, clinicians, hospitals and researchers dedicated to solving the nation’s toughest medical mysteries. The doctors and scientists in the network harness advances in genetic science to identify rare, sometimes unknown, illnesses.
At UCLA, one of the network’s sites, Andrew’s medical team would later map his genetic makeup, then bring him in for a week of exams and consultations with specialists.
Writing A New Disease Encyclopedia
The Undiagnosed Diseases Network was founded in 2015 with a $43 million grant from the National Institutes of Health (NIH). Building on work already being done at NIH, the initiative expanded to include universities across the country: Duke, Columbia and Stanford are among the other sites. The goals are to provide answers for patients with mysterious diseases and to learn more about the disorders.
A proposal last month by President Donald Trump to cut the NIH budget by $5.8 billion could put the program in jeopardy.
Even with the best technology and the finest brains at work, progress is slow. Since its launch, the network has received nearly 1,400 applications on behalf of patients. It has accepted 545 for review so far. Just 74 of the cases have been diagnosed, including 11 at UCLA. Andrew Whittaker’s case is among many in progress.
It’s like battling “an unknown enemy,” said Euan Ashley, one of the principal investigators of the network’s Stanford University site. “That is a particular form of torment that other patients don’t have.”
A diagnosis can end families’ painful odyssey while helping physicians and scientists better understand rare diseases and human physiology, said Rachel Ramoni, former executive director of the network, which is based at Harvard University.
Researchers throughout the network use advanced medical technology. For example, to study patients’ gene expression and disease progression, they can make models using nearly transparent zebrafish, whose genetic structure is similar to that of humans. And scientists can conduct whole genome sequencing, which allows the medical team to read a patient’s DNA and identify changes that can reveal what may be causing a disease.
“We have powerful techniques to look at every gene that is being expressed as well as every gene that is inherited,” said Stanley Nelson, one of UCLA’s principal investigators and the lead doctor on Andrew’s case. “This is an example of true precision medicine.”
Nelson said the network can examine all known genes — not just the ones believed to have mutations that cause diseases. Doing that can lead to the discovery of new illnesses.
“Part of what we have to do is keep building that library, that encyclopedia of what gene and what gene mutations cause what symptoms,” Nelson said. “It’s just incomplete at this moment.”
Already the work is helping patients and their families come to terms with their illnesses. In one case, at Stanford, a toddler was diagnosed with two rare diseases, including a connective tissue disorder called Marfan Syndrome, after doctors conducted a form of sequencing that looks for changes in coded genetic segments known as exons.
Sometimes answers come from something decidedly lower-tech: collaboration among clinicians and researchers who share experiences, data and expertise.
“A lot of times your ability to be diagnosed depends on who is in the room,” Ramoni said. “And what we are doing with the network is we are expanding exponentially the number of people in the room.”
Doctors at one institution might think their patient is a unique case, only to learn that colleagues elsewhere have a patient with a similar illness. But even when diseases are diagnosed or gene mutations are discovered, treatments may still not be available.
A Life-Changing Mystery
Andrew Whittaker’s odyssey began one afternoon at age 19, when he started trembling and couldn’t speak. Doctors suspected he was suffering from anxiety and prescribed medication to control it. But Andrew said he continued to have “episodes,” during which everything just went blank.
“It’s like there’s not enough blood going to your brain,” he said. “You can’t think.”
Andrew also started losing his balance and falling off his bicycle. The family visited several hospitals. Doctors discovered that the receptors in his brain were malfunctioning and that he lacked sufficient dopamine, a chemical compound in the body responsible for transmitting signals between nerve cells. As a result, Andrew has some symptoms similar to those of Parkinson’s disease. Doctors also confirmed he was having seizures.
Still, Andrew’s symptoms didn’t add up to any known disease.
One afternoon last fall at precisely noon, as Andrew sat propped up on the living room couch, Lynn’s phone alarm sounded, signaling it was time for his medication. Lynn pried open Andrew’s hand, which was clenched into a fist, and dropped in the pills.
To keep Andrew from falling, the family has lowered his bed and removed carpet from the house. They also bought him a wheelchair. Their precautions don’t always work. One morning, Lynn was in the kitchen when she heard a crash. “I ran in there and he’s laid flat on his back,” she said.
Lynn gives Andrew his medicine. (Heidi de Marco/KHN)
Lynn says not knowing what is causing her son’s disease is devastating. “We don’t know what we are dealing with,” she says. “We just know it’s worsening … and it’s like somebody ripping your insides out.” (Heidi de Marco/KHN)
Andrew is close to his mom. But he also gets frustrated. He can’t shower or dress without her help. He’s had to give up the things he loved to do: printing T-shirts. Skateboarding. Shooting short films. He’s lost friends and can’t imagine dating anymore.
“Girlfriends? Forget about it,” he said, his face twitching as he talks. “They want a guy who can do stuff for them, not the other way around.”
Running The Medical Gauntlet
On a Monday morning in late January, Andrew and his parents were in an exam room at UCLA. Lynn teased her son, saying she was going to put him in a freezer until doctors figured out what was wrong.
“Then we’ll pull you back out again,” she said, smiling.
“I’ll never get pulled out,” Andrew responded.
“Yes, you will,” she said. “You will.”
Nelson, Andrew’s main doctor, walked into the room. He told Andrew he’d read through the medical records. “We’re going to try to figure you out.”
The work Nelson does is personal. His teenage son, Dylan, has Duchenne muscular dystrophy, a genetic disorder that causes muscle degeneration and weakness. Nelson knows his son’s disease will eventually take his life, but he said having a diagnosis makes all the difference.
“My heart very much goes out to the families that don’t even get an adequate diagnosis,” he said.
Nelson suspects that Andrew’s disease is genetic as well.
He asked the Whittakers to describe their son’s journey, then he conducted a short physical exam, asking Andrew to push against his hand and touch his own nose. Andrew trembled and his shoulders tensed, but he did it.
The rest of the week, Andrew underwent several other diagnostic tests, including a muscle biopsy, an EEG, MRI and a lumbar puncture. He remained upbeat, though running the medical gauntlet clearly wore him out. He also met with UCLA specialists in brain degeneration and muscle and nerve disorders.
At week’s end, Nelson sat down with the family to explain what he’d found. He had reviewed Andrew’s genome and compared it with that of both parents. Andrew had one copy of a defective gene that leads to Parkinson’s but the genome sequencing didn’t show a second copy, without which it could not be Parkinson’s.
He explained that Andrew’s illness was clearly progressive and that his brain was shrinking, making it harder for him to process language and information. Nelson said he still didn’t have a diagnosis — he believed it was a brand-new disease.
Nelson planned to continue poring over the test results, conducting additional exams and communicating with others in the network. He also is analyzing Andrew’s muscle tissue, skin and blood to see whether any mutated gene is expressed abnormally.
Even in the absence of a clear diagnosis, Nelson said, rare diseases like Andrew’s help educate scientists and may help other patients. “These are the people we as a society will owe a great debt of gratitude,” he said. “They are effectively donating their lives to this process.”
Lynn Whittaker was disappointed. “We are still left with just hope that they will come up with something,” she lamented. “What else do we have?”
Andrew said his relatives have asked if he’s scared the doctors will find something. “I’m more scared if they don’t,” he replied.
An international team based at Geneva University Hospitals (HUG) and at the University of Geneva (UNIGE), Switzerland, has succeeded in defining a “signature” composed of a small number of inflammatory markers that can be monitored in order to understand how a promising anti-Ebola virus vaccine stimulates the immune system. The researchers inoculated 115 volunteers with either a high dose or a low dose of the rVSV-ZEBOV anti-Ebola vaccine, or with placebo. By analyzing the differences between the three groups, they found that it is sufficient to monitor only 5 substances that are naturally present in the blood in order to define immune responses to the vaccine. The “Geneva rVSV-ZEBOV signature” is published in a scientific paper, in Science Translational Medicine. It’s an easy-to-use equation adding up the concentrations of these 5 substances or markers, most of which are mediated by monocytes, a class of white blood cells known to be active in combatting Ebolavirus in infected individuals. The signature is also expected to inform investigations of safety and immunogenicity of other emerging vaccines.
The 2014–2015 Ebola epidemic affected several countries in West Africa, leading to the death of more than 11’000 people. Although this epidemic of Ebolavirus disease is over, there is no knowing if, when or where another may strike. It is therefore more important than ever to find a reliable vaccine against this deadly disease. Research on vaccines, which was ongoing during the epidemic in West Africa, is now yielding promising results.
Important progress in understanding the vaccine
In an article published on April 12, 2017, in Science Translational Medicine, a team from the HUG and the UNIGE, working in collaboration with researchers and clinicians in several other countries in Europe and Africa, has defined a formula that measures the reliability and efficiency of vaccines that might help prevent or limit future outbreaks.
The rVSV-ZEBOV vaccine (recombinant vesicular stomatitis virus–vectored Zaire Ebola vaccine) had already been shown to stimulate the immune system in human volunteers; and in a field trial in 2015 it successfully protected people who had been exposed to Ebola patients from contracting the disease themselves. Yet concerns had been raised during the Geneva trial regarding side effects. What the Geneva team has now published is a detailed examination of the blood plasma of 115 healthy volunteers from Geneva, some of whom received either a low-dose or a high dose of vaccine, while others received a placebo vaccine.
When a vaccine enters the bloodstream, dozens of inflammatory markers that are naturally present see their concentrations change over the next few days. The researchers investigated 15 of them (different varieties of chemokines or cytokines). They found that 1-3 days after the vaccine was administered, the concentration of 6 of these 15 markers had measurably increased. Using a statistical procedure known as principal components analysis, the Geneva team succeeded in producing a simple score that makes the activity of the vaccine much easier to monitor. This “signature” contains only 5 of the 6 markers most likely to change in the presence of the rVSV-ZEBOV vaccine: together, they account for over two-thirds (68%) of the variation in blood cytokine/chemokine activity.
The Geneva Signature found in Gabon
The signature was found to be stronger in volunteers who received the higher dose than in those who got the lower dose.
Importantly, the “Geneva signature” was applied to blood samples from a similar trial that took place in Lambaréné, Gabon, where healthy volunteers had also received the rVSV-ZEBOV vaccine. The same markers were elevated and correlated with side effects and later immunity in the same way.
The 5 markers in the signature are: monocyte attractant protein 1 (MCP-1), the interleukin-1 receptor antagonist (IL-1Ra), tumor necrosis factor (TNF-alpha), interleukin-10 and interleukin-6. Several of these are produced by monocytes or are known to interact with them, so the results imply that monocytes play a critical role in the efficacy and safety of the rVSV-ZEBOV vaccine.
In the case of many other vaccines, such as one recently developed against H1N1 influenza, the chemical markers mostly belong to another category of white blood cells: lymphocytes. Taken together, these signatures help understand how vaccines stimulate the immune system in very different ways to tackle various types of virus. This latest discovery therefore opens up encouraging perspectives for investigating the safety, efficacy and mechanisms of other emerging vaccines.
Bacteria are everywhere. And despite widespread belief, not all bacteria are “bad.” However, to combat those that can cause health issues for humans, there has been an over-reliance on the use of antibiotics – so much so, that many of them are now proving ineffective due to bacteria developing increased resistance to them.
“More and more antibiotics are essentially becoming useless,” says Robert Smith, Ph.D., assistant professor in the Department of Biological Sciences at NSU’s Halmos College of Natural Sciences and Oceanography. “Even the most routine infections, such as ear infections that are often seen in children, are becoming more challenging and expensive to treat.”
This notion isn’t new – just prior to winning his Nobel Prize in 1945, Alexander Fleming, the scientist who discovered antibiotics, warned that overusing them would lead to bacteria that were no longer killed by these drugs. Since then, scientists and bacteria have been locked in a deadly arms race. While scientists rush to discover new antibiotics, bacteria fight back by developing new tools to resist antibiotics. In recent years, the bacteria have been winning.
So this paradigm led researchers at NSU to take another look at how bacteria do what they do to see if there was another way to approach this issue. Researchers are now focusing on developing new ways to treat infections that reduce the use of antibiotics. And what the NSU researchers found, working with colleagues from Duke University and the University of Minnesota, was interesting.
Their findings are detailed in the March 27th edition of Scientific Reports (http://www.nature.com/articles/s41598-017-00588-9).
One way that bacteria infect people is by working together. First, they build a home called a biofilm, and then use chemicals to “talk with each other.” This allows the bacteria to coordinate an attack on the infected person. Led by NSU graduate Cortney Wilson, Smith’s lab recently discovered that by shaking the house that the bacteria have built, the ability of the bacteria to talk to one another is affected. Wilson earned her Master’s from NSU and is now at the University of Colorado, Boulder.
“We found that shaking the bacteria forced them to face a decision; do they want to grow, or do they want to cooperate,” Smith said. “And if we shook them at just the right frequency, we created enough confusion that the bacteria could do neither effectively.”
Smith notes that this strategy to prevent bacteria from talking to one another has promise in reducing the need for antibiotics. The team of scientists hope to begin testing their theory in more species of bacteria, and eventually in mice.
“It is a very exciting time for our research team. We are looking forward to building upon our very promising results and to moving our strategy into the clinic.”
A team led by engineers at the University of California San Diego has developed nanowires that can record the electrical activity of neurons in fine detail. The new nanowire technology could one day serve as a platform to screen drugs for neurological diseases and could enable researchers to better understand how single cells communicate in large neuronal networks.
“We’re developing tools that will allow us to dig deeper into the science of how the brain works,” said Shadi Dayeh, an electrical engineering professor at the UC San Diego Jacobs School of Engineering and the team’s lead investigator.
“We envision that this nanowire technology could be used on stem-cell-derived brain models to identify the most effective drugs for neurological diseases,” said Anne Bang, director of cell biology at the Conrad Prebys Center for Chemical Genomics at the Sanford Burnham Medical Research Institute.
The project was a collaborative effort between the Dayeh and Bang labs, neurobiologists at UC San Diego, and researchers at Nanyang Technological University in Singapore and Sandia National Laboratories. The researchers published their work Apr. 10 in Nano Letters.
Researchers can uncover details about a neuron’s health, activity and response to drugs by measuring ion channel currents and changes in its intracellular potential, which is due to the difference in ion concentration between the inside and outside of the cell. The state-of-the-art measurement technique is sensitive to small potential changes and provides readings with high signal-to-noise ratios. However, this method is destructive — it can break the cell membrane and eventually kill the cell. It is also limited to analyzing only one cell at a time, making it impractical for studying large networks of neurons, which are how they are naturally arranged in the body.
“Existing high sensitivity measurement techniques are not scalable to 2D and 3D tissue-like structures cultured in vitro,” Dayeh said. “The development of a nanoscale technology that can measure rapid and minute potential changes in neuronal cellular networks could accelerate drug development for diseases of the central and peripheral nervous systems.”
The nanowire technology developed in Dayeh’s laboratory is nondestructive and can simultaneously measure potential changes in multiple neurons — with the high sensitivity and resolution achieved by the current state of the art.
The device consists of an array of silicon nanowires densely packed on a small chip patterned with nickel electrode leads that are coated with silica. The nanowires poke inside cells without damaging them and are sensitive enough to measure small potential changes that are a fraction of or a few millivolts in magnitude. Researchers used the nanowires to record the electrical activity of neurons that were isolated from mice and derived from human induced pluripotent stem cells. These neurons survived and continued functioning for at least six weeks while interfaced with the nanowire array in vitro.
Silicidation is usually used to make contacts to transistors, but this is the first time it is being used to do patterned wafer bonding, Dayeh said. “And since this process is used in semiconductor device fabrication, we can integrate versions of these nanowires with CMOS electronics.” Dayeh’s laboratory holds several pending patent applications for this technology.
To overcome this hurdle, researchers invented a new wafer bonding approach to fuse the silicon nanowires to the nickel electrodes. Their approach involved a process called silicidation, which is a reaction that binds two solids (silicon and another metal) together without melting either material. This process prevents the nickel electrodes from liquidizing, spreading out and shorting adjacent electrode leads.
Dayeh noted that the technology needs further optimization for brain-on-chip drug screening. His team is working to extend the application of the technology to heart-on-chip drug screening for cardiac diseases and in vivo brain mapping, which is still several years away due to significant technological and biological challenges that the researchers need to overcome. “Our ultimate goal is to translate this technology to a device that can be implanted in the brain.”
Researchers in Germany have developed a transgenic mouse that could help scientists identify new influenza virus strains with the potential to cause a global pandemic. The mouse is described in a study, “In vivo evasion of MxA by avian influenza viruses requires human signature in the viral nucleoprotein,” that will be published April 10 in The Journal of Experimental Medicine.
Influenza A viruses can cause devastating pandemics when they are transmitted to humans from pigs, birds, or other animal species. To cross the species barrier and establish themselves in the human population, influenza strains must acquire mutations that allow them to evade components of the human immune system, including, perhaps, the innate immune protein MxA. This protein can protect cultured human cells from avian influenza viruses but is ineffective against strains that have acquired the ability to infect humans.
To investigate whether MxA provides a similar barrier to cross-species infection in vivo, Peter Staeheli and colleagues at the Institute of Virology, Medical Center University of Freiburg, created transgenic mice that express human, rather than mouse, MxA. Similar to the results obtained with cultured human cells, the transgenic mice were resistant to avian influenza viruses but susceptible to flu viruses of human origin.
MxA is thought to target influenza A by binding to the nucleoprotein that encapsulates the virus’ genome, and mutations in this nucleoprotein have been linked to the virus’ ability to infect human cells. Staeheli and colleagues found that an avian influenza virus engineered to contain these mutations was able to infect and cause disease in the transgenic mice expressing human MxA.
MxA is therefore a barrier against cross-species influenza A infection, but one that the virus can evade through a few mutations in its nucleoprotein. Staeheli and colleagues think that their transgenic mice could help monitor the potential dangers of emerging viral strains. “Our MxA-transgenic mouse can readily distinguish between MxA-sensitive influenza virus strains and virus strains that can evade MxA restriction and, consequently, possess a high pandemic potential in humans,” Staeheli says. “Such analyses could complement current risk assessment strategies of emerging influenza viruses, including viral genome sequencing and screening for alterations in known viral virulence genes.”
Interventions for babies at risk could be started at birth to prevent disease
Findings published in the Journal of Pediatrics describe growth factors in cord blood that may identify premature infants at risk for bronchopulmonary dysplasia-associated pulmonary hypertension (BPD-PH) – an often fatal lung disease in which the vessels carrying blood from the heart to the lungs become narrowed and dysfunctional. Identifying these babies at birth would allow earlier interventions to prevent the disease that manifests in some preemies two to three months after birth.
“We have many promising interventions and it would be exciting to start them at birth in babies at risk, before they become extremely sick,” said lead author Karen Mestan, MD, a neonatologist at Ann & Robert H. Lurie Children’s Hospital of Chicago and Associate Professor at Northwestern University Feinberg School of Medicine. “Currently we do not use cord blood for prediction of disease, but our study shows that it has tremendous potential to save lives.”
Using a large repository of cord blood and placental tissues from a wide gestational age range, Mestan and colleagues examined 15 biomarkers in cord blood, looking for correlations with lesions in the placenta that cause insufficient blood flow between the mother and fetus. They found that two growth factors – granulocyte colony-stimulating factor (G-CSF) and placental growth factor (PlGF) – were decreased with these placental lesions. They also found that these two growth factors were almost undetectable in extremely premature babies who later developed BPD-PH, as opposed to others who escaped the disease. The team validated these findings in a large sample of babies born at less than 28 weeks of gestation.
“Our findings also have implications for what we do during pregnancy,” said Mestan. “The growth factors we identified potentially could be measured in the mom’s blood, and if they are low, that would signal lesions in the placenta that place the baby at risk for severe lung disease. Better understanding about fetal origins of disease, which is still a mystery, would help us find new ways to improve outcomes even before the child is born.”
While the findings do not establish that deficiency in the two growth factors causes BPD-PH, they suggest a possible mechanism behind the disease. “There are many undifferentiated stem cells in cord blood and these growth factors might help mobilize them to get assigned to specific immune functions involved in the healing process,” said Mestan. “Preemies who are deficient in G-CSF and PlGF might not be able to fight off the development of lung damage. But what if we could replenish these babies with healthier stem cells or even replenish the growth factors? We could then regenerate lung tissue. This is a thrilling area of research that could have huge impact.”
Larger, multicenter studies are needed to validate findings before the growth factors can be used clinically to identify premature infants at risk for BPD-PH in order to initiate earlier interventions.
A recently-published study shows how Indiana University scientists are speeding the path to new treatments for the Zika virus, an infectious disease linked to birth defects in infants in South and Central America and the United States.
Cheng Kao, a professor in the IU Bloomington College of Arts and Sciences‘ Department of Molecular and Cellular Biochemistry, has mapped a key protein that causes the virus to reproduce and spread.
“Mapping this protein provides us the ability to reproduce a key part of the Zika virus in a lab,” Kao said. “This means we can quickly analyze existing drugs and other compounds that can disrupt the spread of the virus. Drugs to target the Zika virus will almost certainly involve this protein.”
The World Health Organization reports that more than 1 million people in 52 countries and territories in the Americas have been infected with the Zika virus since 2015. The disease has also been confirmed to cause microcephaly in more than 2,700 infants born to women infected with the virus while pregnant. Symptoms include neurological disorders and a head that is significantly smaller than normal.
The virus is also transmissible through sexual activity and can trigger an autoimmune disease in adults called Guillain-Barre syndrome.
The IU-led study, conducted in collaboration with Texas A&M University, revealed the structure of the Zika virus protein NS5, which contains two enzymes needed for the virus to replicate and spread. The first enzyme reduces the body’s ability to mount an immune response against infection. The other enzyme helps “kick off” the replication process.
“We need to do everything we can to find effective drugs against the Zika virus, as changes in travel and climate have caused more tropical diseases to move into new parts of the globe,” said Kao, who has also spent 15 years studying the virus that causes hepatitis C.
“We’ve learned a lot of lessons about how to fight this class of virus through previous work on hepatitis C, as well as other work on the HIV/AIDS virus,” he added.
In addition, Kao said, the study showed that the Zika virus protein is similar in structure to proteins from viruses that cause dengue fever, West Nile virus, Japanese encephalitis virus and hepatitis C, which prompted the team to test several compounds that combat those diseases. The team also tested other compounds to disrupt the virus’s replication.
“Drugs approved to treat hepatitis C and compounds in development to treat other viral diseases are prime candidates to use against the Zika virus,” Kao said. “We’re continuing to work with industry partners to screen compounds for effectiveness against the NS5 protein.”
Other IU Bloomington authors on the study were Guanghui Yi and Yin-Chih Chuang in the Department of Molecular and Cellular Biochemistry and Robert C. Vaughan in the Department of Biology. Additional authors were Baoyu Zhao and Pingwei Li of Texas A&M University and Banumathi Sankaran at Lawrence Berkeley National Laboratory.
The method used to reproduce the virus protein in the lab is the subject of a U.S. patent application filed by the IU Research and Technology Corp.
The study appears in the journal Nature Communications. It was supported in part by the Johnson Center for Innovation and Translational Research at IU Bloomington.
Scientists identify two signaling proteins in cancer cells that make them resistant to chemotherapy, and show that blocking the proteins along with chemotherapy eliminate human leukemia in mouse models.
Reporting results March 20 in Nature Medicine, researchers at Cincinnati Children’s Hospital Medical Center suggest that blocking the signaling proteins c-Fos and Dusp1 as part of combination therapy might cure several types of kinase-driven, treatment-resistant leukemia and solid tumor cancers.
These include acute myeloid leukemia (AML) fueled by the gene FLT3, lung cancers fueled by genes EGFR and PDGFR, HER2-driven breast cancers, and BCR-ABL-fueled chronic myeloid leukemia (CML), according to Mohammad Azam, PhD, lead investigator and a member of the Division of Experimental Hematology and Cancer Biology.
“We think that within the next five years our data will change the way people think about cancer development and targeted therapy,” Azam says. “This study identifies a potential Achilles heel of kinase-driven cancers and what we propose is intended to be curative, not just treatment.”
The weak spot is a common point of passage in cells (a signaling node) that appears to be required to generate cancer cells in both leukemia and solid tumors. The node is formed by the signaling proteins c-Fos and Dusp1, according to study authors. The researchers identified c-Fos and Dusp1 by conducting global gene expression analysis of mouse leukemia cells and human chronic myeloid leukemia (CML) cells donated by patients.
CML is a blood cancer driven by an enzyme called tyrosine kinase, which is formed by the fusion gene BCR-ABL. This fusion gene is the product of translocated chromosomes involving genes BCR (chromosome 22) and ABL (chromosome 9). Analysis of human CML cells revealed extremely high levels of c-FOS and DUSP1 in BCR-ABL-positive chemotherapy resistant cells.
Cancer sleeper cells
Cancer cells often become addicted to the mutated gene that causes them, such as BCR-ABL in kinase-driven chronic myeloid leukemia. Most chemotherapies work by blocking molecular pathways affected by the gene to shut down the disease process. In the case of CML, a chemotherapy called imatinib is used to block tyrosine kinase, which initially stops the disease. Unfortunately the therapeutic benefit is temporary and the leukemia comes back.
Azam and colleagues show in their CML models that signaling from tyrosine kinase – and growth factor proteins that support cell expansion (like interleukins IL3, IL6, etc.) – converge to dramatically elevate c-Fos and Dusp1 levels in the cancer cells.
Working together these molecules maintain the survival of cancer stem cells and minimal residual disease. The dormant cells wait around under the radar screen to rekindle the disease by acquiring additional genetic mutations after initially effective chemotherapy.
Azam says Dusp1 and c-Fos support the survival of cancer stem cells by increasing the toxic threshold needed to kill them. This means conventional imatinib chemotherapy will not eliminate the residual disease stem cells. Doctors can’t just increase the dose of chemotherapy because it doesn’t target the Dusp1 and c-Fos proteins that regulate toxic threshold.
Targeting c-Fos and Dusp1
After identifying c-Fos and Dusp1, the authors tested different treatment combinations on mouse models of CML, human CML cells, and mice transplanted with human leukemia cells. They also tested treatments on B-cell acute lymphoblastic leukemia (B-ALL).
The treatment combinations included: 1) solo therapy with just the tyrosine kinase inhibitor, imatinib; 2) solo treatment with just inhibitors of c-Fos and Dusp1; 3) treatment with all three combined – imatinib along with molecular inhibitors of c-Fos and Dusp1.
As suspected, treatment with imatinib alone initially stopped CML progression but the leukemia relapsed with the continued presence of residual disease cells. Treatment with c-Fos and Dusp1 inhibitors alone significantly slowed CML progression and prolonged survival in a majority of mice but wasn’t curative. Treatment for one month with c-Fos/Dusp1 inhibitors and imatinib cured 90 percent of mice with CML, with no signs of residual disease cells.
Azam and his colleagues also point to an interesting finding involving solo treatment with just the deletion of c-Fos and Dusp1. This eliminated expression of the signaling proteins and was sufficient to block B-ALL development, eradicating the disease in mouse models.
The authors stress that because the study was conducted in laboratory mouse models, additional research is needed before the therapeutic strategy can be tested in clinical trials.
They are following up the current study by testing c-Fos and Dusp1as treatment targets for different kinase-fueled cancers, including certain types of lung cancer, breast cancers and acute forms of leukemia.
UCLA researchers have discovered the molecular basis of, and identified potential treatment for, an incurable disease known as inclusion body myopathy, Paget disease with frontotemporal dementia, or IBMPFD. Using both genetically engineered fruit flies that have the fly equivalent of the disease gene as well as cells from people with IBMPFD, the researchers discovered how mutations carried by those with IBMPFD cause cellular damage. They also identified two compounds that are able to reverse the effects of IBMPFD-associated mutations in flies and human IBMPFD cells. The findings suggest potential strategies to combat IBMPFD and other degenerative diseases, including amyotrophic lateral sclerosis, commonly known as ALS.
IBMPFD is an inherited disorder that affects the muscles, the brain and bones. Most people with the disorder show progressive muscle weakness, or myopathy, leading to mobility loss or even respiratory failure. Others develop dementia that predominantly affects language and behavior. No treatment is available to halt progression of the disease. Prior studies showed that mutations in a gene that encodes Valosin-Containing Protein, known as VSP, cause IBMPFD and some forms of ALS. Moreover, in people with IBMPFD, mitochondria, the energy-generating powerhouse of the cell, do not produce energy properly. However, it was not clear how VSP mutations disrupt mitochondria and how this disruption leads to disease.
The team created fruit flies that are given the disease in their muscles, which results in multiple defects, including muscle cell death, similar to that seen in patients. In addition, abnormally small, fragmented mitochondria appeared, a sign of mitochondrial distress. This led the team to examine a protein called Mitofusin which controls mitochondria fusion, maintaining mitochondrial energy-production capacity in healthy cells. The team showed that VSP normally degrades Mitofusin, but mutant VCP is abnormally overactive, and promotes excessive degradation of Mitofusin. This discovery explains how cellular damage occurs. Most importantly, flies fed VCP-inhibiting compounds showed reversal of muscle wasting and mitochondrial fragmentation. Patient cells treated with the same compounds showed similar positive responses.
Biomedical researchers are increasingly aware that defects in mitochondrial fusion are a hallmark of conditions ranging from Parkinson’s disease, heart disease to diabetes. This paper reveals how mutant VCP can cause cellular destruction seen in IBMPFD by interfering with proteins responsible for controlling mitochondrial fusion. Importantly, VCP inhibitors can reverse the pathology of IBMPFD in flies and in patient cells. VCP inhibitors are currently being studied in clinical trials for cancer. This raises the possibility of using VCP inhibitors for treatments of IBMPFD and other diseases caused by VCP mutations, such as ALS, peripheral neuropathy and hereditary spastic paraplegia.
Not all melanomas are created equal. While most melanomas appear on the skin as the result of sun exposure, a small subset of melanomas arise spontaneously from mucosal tissues. And while targeted treatments and immunotherapies have dramatically improved the prognosis for many patients with sun-associated melanomas, these treatments are ineffective in the mucosal form of the disease. A University of Colorado Cancer Center study published today in the journal Melanoma Research uses the unique resource of over 600 melanoma samples collected at the university to demonstrate, for the first time, novel mutations involved in mucosal melanoma, paving the way for therapies to treat this overlooked subtype.
“The treatment for melanoma has gotten pretty good in the past five years. But this is a different disease and the treatments that work in sun-caused melanoma don’t work in non-sun melanoma,” says William A. Robinson, MD, investigator at the CU Cancer Center and the Rella and Monroe Rifkin Endowed Chair of Medical Oncology at the CU School of Medicine. Robinson founded the melanoma tissue bank at CU, which has grown into a major national resource for scientists studying the disease.
The study compared whole-exome sequencing data from 19 patient samples of mucosal melanoma to 135 samples of sun-exposed melanoma. Importantly, mutations in the BRAF gene that are seen in more than half of advanced melanomas were absent in mucosal melanoma, explaining the ineffectiveness of BRAF-targeted treatments like vemurafenib. Instead, 32 percent of mucosal melanomas showed co-mutation of the genes KIT and NF1. Also, the paper reports mutations in the gene SF3B1 present in 37 percent of mucosal melanoma samples.
“We have seen SF3B1 mutation in chronic lymphocytic leukemia and in myeloid dysplastic disorders, and now we show its importance in mucosal melanoma,” says Aik Choon Tan, PhD, investigator at the CU Cancer Center and associate professor of Bioinformatics at the CU School of Medicine.
Because any sample of cancer cells is likely to contain thousands of mutations, advanced analytic tools are needed to distinguish harmless “passenger” mutations from the dangerous mutations driving the disease. For this purpose, the researchers used the computational tool IMPACT, developed in the Tan lab, to sort functional from missense mutations and to cross-reference candidate mutations with those previously reported in other cancer types.
“For the first time, this process demonstrates the functional role of SF3B1 in mucosal melanoma,” Robinson says.
The mechanics of SF3B1 are complex and only partially understood. Basically, the gene makes a molecule involved in preparing other genes for expression, helping to distinguish between regions of genes that should be manufactured and those that are silent genetic filler. Technically, SF3B1 sorts “exons” from “introns” – helping to cut and splice genetic code into the streamlined version that forms the plan for a protein. Unfortunately, if SF3B1 is mutated, this cutting and pasting can go awry in ways that introduce unintended bits of introns along with the intended bits of exons into the blueprint.
“Most often when material from introns is improperly included with exons, the result is nonsense proteins that go on to quickly degrade, meaning that cancer may use this strategy to downregulate the production of certain anti-cancer proteins,” Tan says. “On the other hand, an SF3B1 mutation could result in changes to the protein that are helpful to cancer cells, meaning that mucosal melanoma may be using this strategy to upregulate the production of proteins that can drive its growth.”
No matter if SF3B1 is nixing good proteins or boosting bad ones, the current project shows that stopping its action could benefit patients with mucosal melanoma. In fact, the researchers point out that phase 1 clinical trials are already underway for compounds targeting this gene in other cancers, meaning that the time needed to apply a similar strategy to mucosal melanoma could be dramatically shorter than if they had to start from scratch.
The group plans to continue exploring the mechanics of SF3B1 while also pushing forward with the preclinical work needed to form the rational basis for targeting this gene in patients with advanced mucosal melanoma.
A new study in mice reveals that eosinophils, a type of disease-fighting white blood cell, appear to be at least partly responsible for the progression of heart muscle inflammation to heart failure in mice.
In a report on the findings, published in The Journal of Experimental Medicine on March 16, researchers found that while eosinophils are not required for heart inflammation to occur, they are needed for it to progress to a condition known as inflammatory dilated cardiomyopathy (DCMi) in mice. The discovery, they say, advances information about the impact of eosinophils on heart function.
“Other studies have shown that people with high levels of eosinophils develop a number of heart diseases. This new work has provided more details about how these immune system cells may lead to deterioration of heart muscle function in mice in a way that lets us draw some parallels to human disease processes,” says Daniela Cihakova, M.D., Ph.D., associate professor of pathology at the Johns Hopkins University School of Medicine and the paper’s senior author.
Heart inflammation, or myocarditis, is rarely diagnosed because it doesn’t always cause severe symptoms and it requires a biopsy to be taken from the patient’s heart. This makes it difficult to study the outcomes of the disease. “We don’t understand why the hearts of some people will heal while those of others develop chronic disease,” says Cihakova.
Different types of myocarditis are distinguished based on the type of immune cell that predominates the inflammation of the heart. For example, in eosinophilic myocarditis, numerous eosinophils infiltrate the heart. It is not known if some types of myocarditis are more likely to progress to DCMi than others. “Our studies show that the presence of eosinophils in the heart makes mice more likely to get DCMi following myocarditis. And if there are a lot of eosinophils, the mice develop even more severe heart failure,” says Nicola Diny, a Ph.D. student in the Bloomberg School of Public Health and the study’s first author. “It will be important to test if the same is true in patients. That way, we may be able to intervene early and prevent DCMi.”
This study, says Cihakova, is the first to examine the role eosinophils play in the development and severity of heart inflammation, and the subsequent progression of inflammation to DCMi. The study addresses a National Institutes of Health-identified need for preclinical models and a clearer understanding of how eosinophils drive heart damage.
For the study, Cihakova and her team first induced myocarditis in two groups of mice: normal mice and a group of mice genetically modified to be eosinophil-deficient. Myocarditis was induced through a process called experimental autoimmune myocarditis, in which mice are immunized with a peptide from heart muscle cells to initiate an immune response against the heart. After 21 days, the researchers found similar levels of acute inflammation in the hearts of both groups by studying the hearts’ tissue. But when the team checked the mice’s hearts later on for evidence of heart failure, the differences between the eosinophil-deficient and the normal mice were striking. The normal mice developed heart failure, while the eosinophil-deficient mice showed no signs of reduced heart function.
“These surprising results told us that it is not the overall severity of inflammation but rather the types of immune cells in the heart that decide whether myocarditis develops into heart failure,” says Diny.
The researchers also examined the hearts for fibrosis, or scar tissue, which develops when mammalian (including human) heart muscles die. This type of scar tissue is also found in DCMi. Although both groups of mice had similar degrees of scar tissue, the eosinophil-deficient mice’s heart functions weren’t negatively affected, while the normal mice developed DCMi.
“This told us that in the absence of eosinophils, heart function can be preserved despite scar tissue formation,” Cihakova says. “It’s also important to note that although eosinophils accounted for just 1 to 3 percent of all heart-infiltrating cells in normal mice, this small percentage can still drive heart failure.”
In another set of experiments, the research team used genetically modified mice, called IL5Tg mice, which have an excess of the protein IL5 that causes the body to make eosinophils. The IL5Tg mice had more inflammation in the atria, or upper chambers of the heart, compared to normal mice in the acute stage and more atrial scar tissue in the chronic stage. IL5Tg mice also had more heart-infiltrating cells in general. Eosinophils accounted for more than 60 percent of heart-infiltrating cells in the IL5Tg mice’s hearts, compared to only 3 percent in normal mice. When the team examined the heart function some 45 days after the start of the experiment, the IL5Tg mice had developed severe DCMi.
To examine whether humans with eosinophil-driven myocarditis also developed inflammation in the atria, the researchers obtained heart tissue samples and cardiac MRI scans from three patients seen at The Johns Hopkins Hospital, all of whom had confirmed eosinophil-driven inflammation.
The images showed that two patients had either inflammation or scar tissue in the atria, which suggests that atrial inflammation and/or scar tissue may also be a feature in humans with eosinophil-driven inflammation, Cihakova says.
To determine whether the IL5 protein is necessary for DCMi development, the research team next examined IL5-deficient mice. The scientists found that they had both inflammation and DCMi severity similar to that of normal mice, suggesting that the IL5 protein is not necessary for DCMi to develop.
Finally, to confirm the differences between the effects of IL5 and eosinophils, the team bred the eosinophil-deficient mice to have excess IL5. Compared to normal mice, these mice showed no decrease in heart function and appeared completely protected from DCMi, which confirms that it is the eosinophils themselves, not high levels of IL5, that are responsible for DCMi development, the investigators say.
To learn more about how eosinophils might drive DCMi progression, the investigators built on the knowledge that eosinophils harbor granules, some of which can kill cells, while others change the function of cells.
“We didn’t see any differences in cell death between the normal mice and those with or without too many eosinophils, so we became interested in the molecules that can change the function of other cells,” says Diny.
In particular, one protein, called IL4, caught the researchers’ attention. Other studies had shown that IL4 made by eosinophils has diverse functions in liver repair and fat tissue. “We wondered if this protein from eosinophils may also be important in the heart,” Cihakova says.
First, the research team used a mouse in which cells that make IL4 turned fluorescent green, thereby allowing researchers to tell where IL4 is made. The team found that eosinophils accounted for the majority of IL4-producing cells. When they used mice that lacked IL4 in all cells, these mice were completely protected from DCMi, just like the eosinophil-deficient mice.
Finally, to determine whether IL4 specifically from eosinophils is necessary for DCMi development, the team used genetically modified mice with no IL4 in their eosinophils but with IL4 in other heart-infiltrating cells. These mice developed less severe DCMi compared to normal mice, which confirms that eosinophils are responsible for DCMi development through IL4.
“The take-home message is that inflammation severity doesn’t necessarily determine long-term disease progression, but specific infiltrating cell types — eosinophils, in this case — do,” says Cihakova. Because eosinophil-driven inflammation is so clinically rare, the percentage of people who develop DCMi is unknown, she notes.
While no drugs are currently available to stop or delay the development of DCMi, the researchers hope their findings will help establish a novel target for IL4-blocking medicines that might be used to treat people with myocarditis, possibly preventing disease progression and the need for heart transplantation.
Researchers at UT Southwestern Medical Center, working with a California biotech firm, have developed a potential drug to treat polycystic kidney disease – an incurable genetic disease that often leads to end-stage kidney failure.
The drug, now called RGLS4326, is in preclinical animal testing at San Diego-based Regulus Therapeutics Inc. An investigational new drug filing to pave the way for human clinical trials is expected later this year, said Dr. Vishal Patel, Assistant Professor of Internal Medicine at UT Southwestern.
Dr. Patel is senior author of a study describing research that led to the drug’s development, published online today in Nature Communications.
Affecting about 600,000 people in the U.S., autosomal dominant polycystic kidney disease (ADPKD) causes numerous fluid-filled cysts to form in the kidney. An affected kidney, normally the size of a human fist, sometimes grows as large as a football. As their numbers and sizes increase, these cysts eventually interfere with the kidney’s ability to filter blood and remove bodily waste. The cysts can quietly grow for decades until symptoms appear such as blood in the urine, Dr. Patel said. About half of those affected with ADPKD suffer kidney failure by age 60, according to the National Kidney Foundation.
“There isn’t a single drug on the U.S. market right now to treat the disease,” Dr. Patel said. “Once your kidneys fail, your only option for survival is to get a transplant or start dialysis.”
In 2009, Dr. Patel began searching for microRNAs that might underlie progression of ADPKD. MicroRNAs – or MiRs for short – are tiny RNA fragments that interfere with normal gene expression.
Proof that such RNA fragments even existed came in the early 1990s; their presence in humans was first reported in 2000. Those discoveries led to a groundswell of interest in developing drugs to treat diseases caused by microRNAs, Dr. Patel said – in part because the process can be straightforward once the problem-causing fragment is identified.
“Because miRs are so small, drugs can easily be designed against them. And since we know the nucleotide sequence of every known microRNA, all that is required is to prepare an anti-miR with a sequence that is exactly the opposite of the miR’s,” he said.
In this study, researchers in Dr. Patel’s lab focused on microRNA cluster 17~92 following identification of potential miR targets. A National Institutes of Health grant funded the UTSW research. In 2013, Dr. Patel and fellow researchers reported in Proceedings of the National Academy of Sciences that this microRNA cluster indeed appeared to promote kidney cyst growth.
Using four mouse models, the researchers next studied whether inhibiting this microRNA could slow cyst growth and thus delay ADPKD progression. They found that genetically deleting microRNA-17~92 slowed cyst growth and more than doubled the life spans of some mice tested.
Based on that finding, Dr. Patel’s lab collaborated with Regulus Therapeutics to test an anti-microRNA-17 drug. The test drug slowed the growth of kidney cysts in two mouse models and in cell cultures of human kidney cysts, the study showed.
In the Nature Communications study, UTSW researchers also reported how miR-17 causes cyst proliferation: the molecule essentially reprograms the metabolism of kidney cells so that cellular structures called mitochondria use less nutrients, freeing up resources to instead make cell parts that become cysts. MiR-17 accomplishes this by repressing a protein involved in making RNA called peroxisome proliferator-activated receptor alpha (PPARα), the researchers found.
Other UT Southwestern researchers included lead author Dr. Sachin Hajarnis, a research scientist; Dr. Ronak Lakhia, Instructor in Internal Medicine; Matanel Yheskel and Andrea Flaten, research technicians; Darren Williams, former research associate; Dr. Shanrong Zhang, research engineer; Joshua Johnson, an M.D./Ph.D. student; Dr. William Holland and Dr. Christine Kusminski, Assistant Professors of Internal Medicine; and Dr. Philipp Scherer, Professor of Internal Medicine and Cell Biology, who holds the Gifford O. Touchstone, Jr. and Randolph G. Touchstone Distinguished Chair in Diabetes Research.
Also contributing to the study were researchers from the University of Minnesota Medical School, the Mayo Clinic School of Medicine, the University of Montreal, the University of Kansas, and Regulus Therapeutics.
Funding was provided by the National Institutes of Health (NIH) and the PKD Foundation. Research reported in this publication was supported by the National Institute of Diabetes and Digestive and Kidney Diseases of the NIH under Award Number R01DK102572. The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH.
UT Southwestern and Regulus Therapeutics have applied for a patent for treatment of polycystic kidney disease with miR-17 inhibitors. In addition, Dr. Patel’s laboratory has a sponsored research agreement with Regulus, and Dr. Patel serves as a consultant for Regulus.
Physicians at the Johns Hopkins Kimmel Cancer Center report they have successfully treated 16 patients with a rare and lethal form of bone marrow failure called severe aplastic anemia using partially matched bone marrow transplants followed by two high doses of a common chemotherapy drug. In a report on the new transplant-chemo regimen, published online Dec. 22, 2016, in Biology of Blood and Marrow Transplantation, the Johns Hopkins team says that more than a year after their transplants, all of the patients have stopped taking immunosuppressive drugs commonly used to treat the disorder and have no evidence of the disease.
“Our findings have the potential to greatly widen treatment options for the vast majority of severe aplastic anemia patients,” according to Robert Brodsky, M.D., professor of medicine and oncology at the Johns Hopkins Kimmel Cancer Center and an author of the report.
Results of the small clinical trial have already prompted the organization of a larger national trial being led by Amy DeZern, M.D., an assistant professor of oncology and medicine at the Johns Hopkins Kimmel Cancer Center, with plans to involve patients at 25 medical centers across the country.
Diagnosed in about one in 250,000 people each year, aplastic anemia occurs when one’s own immune system damages blood-making bone marrow cells, which gradually stop producing red and white blood cells and platelets.
Patients must receive frequent blood transfusions, take multiple medicines to suppress the autoimmune response that damages the marrow, take other drugs to prevent infections, and limit contact with the outside world to avoid infection and even minor injury. Over the long term, most patients eventually die of infections.
When immunosuppressive therapy fails to keep the disease in check — in as many as 30 to 40 percent of patients — doctors usually prescribe a drug called eltrombopag, which is used in a variety of blood disorders to increase platelets. The drug, according to the Johns Hopkins experts, works only in about 30 percent of patients and usually leads to a partial, not complete, response.
Brodsky and DeZern say that the only curative treatment is a bone marrow transplant, but few patients have donors who are “fully matched” — sharing the same collection of immune-stimulating proteins that decorate every cell in the body.
In an effort to overcome the donor shortage and offer transplant to more patients, DeZern, Brodsky and their colleagues enrolled 16 patients between 11 and 69 years of age in this study from July 2011 through August 2016.
Each of the patients had failed to respond to immunosuppressive therapy or other drug treatments. None had access to a related fully matched bone marrow donor but did have an available and willing donor who was a half match. Three patients used unrelated donors.
After administering a cocktail of drugs designed to suppress their immune system and prevent rejection of the donor marrow, the patients received half-matched bone marrow transplants, some from siblings or parents, and others from unrelated donors.
Three and four days after their transplants, the patients received high doses of the chemotherapy drug cyclophosphamide. For the next year, or slightly longer, they remained on immunosuppressive medications, including tacrolimus, then stopped taking them.
Within weeks of their transplants, tests showed that each of the patients’ red and white blood cell and platelet counts had returned to normal levels without the need for blood transfusions. Once immunosuppressive therapy was stopped, none of the patients required further treatment related to their disease, the Johns Hopkins team reported.
Although 13 patients were able to discontinue immunosuppressive drugs a year after their transplant, three developed mild graft-versus-host disease (GVHD), a common complication of bone marrow transplants that occurs when immune cells in the transplant attack the newly transplanted cells. Two patients had mild GVHD that appeared on their skin, and one patient’s GVHD occurred in the mouth and skin. After a few extra months of immunosuppressive therapy, their GVHD subsided, and they also were able to stop taking these medications.
Ending all therapy related to their disease has been life-changing for the patients, says DeZern. “It’s like night and day,” she says. “They go from not knowing if they have a future to hoping for what they’d hoped for before they got sick. It’s that transformative.”
Successful transplants using partial match donors, Brodsky says, open up the transplant option to nearly all patients with this condition, especially minority patients. Seven of the 16 patients treated at Johns Hopkins self-identified as nonwhite.
A full sibling only has a 25 percent chance of being a full match. However, 100 percent of parents and 50 percent of siblings or half-siblings are half matches, regardless of ethnicity. The average person in the United States has about four half matches or better. “Now, a therapy that used to be available to 25 to 30 percent of patients with severe aplastic anemia is potentially available to more than 95 percent,” says Brodsky.
The idea of using cyclophosphamide after a partial-match transplant was first pioneered decades ago by Johns Hopkins Kimmel Cancer Center experts. Brodsky says the drug destroys patient’s diseased immune system cells but does not harm the donor’s blood stem cells, which create new disease-free blood cells in the patient.
Bone marrow transplants are costly — sometimes exceeding more than $300,000. However, Brodsky and DeZern say that full and half-matched transplants are life-saving for many, and there is cost-saving potential when aplastic anemia patients can avoid a lifetime of immunosuppressive therapy, hospitalizations, medications and blood transfusions.
A panel of small molecules that inhibit Zika virus infection, including one that stands out as a potent inhibitor of Zika viral entry into relevant human cell types, was discovered by researchers from the Perelman School of Medicine at the University of Pennsylvania. Publishing in Cell Reports this week, a team led by Sara Cherry, PhD, an associate professor of Microbiology, screened a library of 2,000 bioactive compounds for their ability to block Zika virus infection in three distinct cell types using two strains of the virus.
Zika is an emerging mosquito-borne virus for which there are no vaccines or specific therapeutics. The team used cells lining brain capillaries called endothelium, and cells from placenta, which represent Zika’s route across the blood-brain barrier and the transmission path from mother to child, respectively. The third type – a human osteosarcoma cell line – is a generic model cell. They tested a strain of Zika virus currently circulating in human populations in the Americas and another from Africa, which is the original strain identified in 1947.
Using a microscopy-based assay, they identified 38 molecules from the High-throughput Screening Core at Penn, which Cherry directs, that inhibited Zika virus infection in at least one cell type. Roughly half of the 2,000 molecules tested include FDA-approved molecules used to prevent viral replication in infected cells. Co-author David Schultz, PhD, the Core’s technical director, was instrumental in providing the infrastructure and expertise for this multi-level screen.
“Overall, the most important finding is that we identified nanchangmycin as a potent inhibitor of Zika virus entry across all cell types tested, including endothelial and placental cells, which are relevant to how Zika may enter the fetus,” Cherry said. Nanchangmycin – an antimicrobial indentified in China as part of a natural medicinal products survey — was also active against other medically relevant viruses, including West Nile, dengue, and chikungunya that use a similar route of entry as Zika.
These viruses enter cells using “clatherin endocytosis.” The virus binds with the host cell’s outer membrane via a pocket lined with a protein called clatherin. This protein-lined sac containing the sequestered virus pinches off to move deeper into the cytoplasm of the cell where the virus enters to replicate.
Nanchangmycin is a “stepping stone to a new class of anti-virals,” Cherry said, because it thwarts this essential mode of entry by viruses like Zika. Future studies will identify the target of this drug and current studies are testing the efficacy of nanchangmycin in animal models of Zika virus infection.
This study was supported by the National Institutes of Health NIH (R01AI074951, RO1AI122749, R01AI095500), the Linda Montague Investigator, Award, and the Burroughs Wellcome Investigators in the Pathogenesis of Infectious Disease Award.
Penn Medicine is one of the world’s leading academic medical centers, dedicated to the related missions of medical education, biomedical research, and excellence in patient care. Penn Medicine consists of the Raymond and Ruth Perelman School of Medicine at the University of Pennsylvania (founded in 1765 as the nation’s first medical school) and the University of Pennsylvania Health System, which together form a $5.3 billion enterprise.
Researchers find key genetic driver for rare type of triple-negative breast cancer
New mouse model leads to surprising discovery that sheds light on metaplastic breast cancer
For more than a decade, Celina Kleer, M.D., has been studying how a poorly understood protein called CCN6 affects breast cancer. To learn more about its role in breast cancer development, Kleer’s lab designed a special mouse model – which led to something unexpected.
They deleted CCN6 from the mammary gland in the mice. This type of model allows researchers to study effects specific to the loss of the protein. As Kleer and her team checked in at different ages, they found delayed development and mammary glands that did not develop properly.
“After a year, the mice started to form mammary gland tumors. These tumors looked identical to human metaplastic breast cancer, with the same characteristics. That was very exciting,” says Kleer, Harold A. Oberman Collegiate Professor of Pathology and director of the Breast Pathology Program at the University of Michigan Comprehensive Cancer Center.
Metaplastic breast cancer is a very rare and aggressive subtype of triple-negative breast cancer – a type considered rare and aggressive of its own. Up to 20 percent of all breast cancers are triple-negative. Only 1 percent are metaplastic.
“Metaplastic breast cancers are challenging to diagnose and treat. In part, the difficulties stem from the lack of mouse models to study this disease,” Kleer says.
So not only did Kleer gain a better understanding of CCN6, but her lab’s findings open the door to a better understanding of this very challenging subtype of breast cancer. The study is published in Oncogene.
“Our hypothesis, based on years of experiments in our lab, was that knocking out this gene would induce breast cancer. But we didn’t know if knocking out CCN6 would be enough to unleash tumors, and if so, when, or what kind,” Kleer says. “Now we have a new mouse model, and a new way of studying metaplastic carcinomas, for which there’s no other model.”
One of the hallmarks of metaplastic breast cancer is that the cells are more mesenchymal, a cell state that enables them to move and invade. Likewise, researchers saw this in their mouse model: knocking down CCN6 induced the process known as the epithelial to mesenchymal transition.
“This process is hard to see in tumors under a microscope. It’s exciting that we see this in the mouse model as well as in patient samples and cell lines,” Kleer says.
The researchers looked at the tumors developed by mice in their new model and identified several potential genes to target with therapeutics. Some of the options, such as p38, already have antibodies or inhibitors against them.
The team’s next steps will be to test these potential therapeutics in the lab, in combination with existing chemotherapies. They will also use the mouse model to gain a better understanding of metaplastic breast cancer and discover new genes that play a role it its development.
“Understanding the disease may lead us to better ways to attack it,” Kleer says. “For patients with metaplastic breast cancer, it doesn’t matter that it’s rare. They want – and they deserve – better treatments.”
Motivated by the tribulations of hemophilia patients and their families, researchers funded by the National Institute of Biomedical Imaging and Bioengineering are working to develop a pill to treat this serious inherited bleeding disorder. Oral delivery of the treatment–clotting factor IX–would allow individuals with type B hemophilia to swallow a pill rather than be subjected to several weekly injections of factor IX to control potentially fatal bleeding episodes.
Such a pill is what Nicholas Peppas, Professor of Biomedical Engineering, Chemical Engineering and Medicine and his team are working to perfect at the University of Texas at Austin’s Institute of Biomaterials, Drug Delivery, and Regenerative Medicine.
Explains David Rampulla, Ph.D., Director of the NIBIB Program in Delivery Systems and Devices for Drugs and Biologics, “The problem with oral delivery is the need to protect proteins such as factor IX in the acidic environment of the stomach but then release them when they reach the small intestine. This is an extraordinary challenge and the Peppas group has spent years developing innovative polymer shells capable of shuttling the protein to its final destination in the digestive tract.”
Hemophilia B is a genetic disorder, which occurs in boys who have a defective factor IX gene that resides on the X chromosome they receive from their mother. The result is a deficiency of the factor IX protein, which the body needs for blood to clot. Though mothers carry the defect, they do not have the disease because they have a normal factor IX gene on their other X chromosome. It is very rare, but one way a daughter might inherit hemophilia is if her father has it and her mother carries the gene for hemophilia as well.
“Multiple weekly injections of factor IX is very difficult for the boys who need the clotting factor to avoid potentially fatal bleeding episodes, as well as for their families” said Peppas. “However, in working with these families, we soon learned that there was also an emotionally draining aspect for mothers, who carry the burden that they passed this disorder on to their sons. This has added an urgency to our research because we know that oral administration of factor IX would be a great relief for these families.”
Peppas and his team are using their skills in advanced materials, and chemical and biomolecular engineering to develop a capsule — actually a sophisticated delivery system – that can carry the swallowed factor IX protein to the small intestine, where it is absorbed and then released into the bloodstream. The current work is described in the November 30 issue of the International Journal of Pharmaceutics.
Outsmarting a harsh and variable digestive system
If one were to swallow the factor IX protein alone it would be quickly digested by stomach acids and lose its biological activity as a clotting factor. Thus, the researchers engineered a protective polymer capsule that has multiple critical functions in the changing environment of the gastrointestinal tract.
First, the polymer is designed to be impervious to harsh stomach acids, such as pepsin in order to protect the factor IX protein from being digested. Second, the capsule moves through the stomach and into the small intestine, which contains the protease, trypsin. The polymer is engineered to be degraded by trypsin, allowing the intestinal fluids to enter and swell the capsule. This swelling promotes degradation of the capsule and release of the clotting factor for absorption into the bloodstream.
The most recent version of the polymer has been improved from previous designs because it is highly biodegradable in the neutral pH of the small intestine. The new biodegradable capsule promotes a several-fold increase in the absorption of factor IX through the intestinal wall. The result is that each capsule can deliver more of the factor IX protein into the bloodstream.
Building on years of improvement in the capsule polymer design, the most recent results in experimental cell culture systems indicate that taking two capsules of the current formulation orally can deliver as much factor IX as a single needle injection.
Having reached this benchmark, Peppas is collaborating with industry to accelerate the necessary testing required in animals with the aim of moving to human clinical trials and FDA approval as rapidly as possible.
Defects in the body’s regulatory T cells (T reg cells) cause inflammation and autoimmune disease by altering the type of bacteria living in the gut, researchers from The University of Texas Health Science Center at Houston have discovered. The study, “Resetting microbiota by Lactobacillus reuteri inhibits T reg deficiency–induced autoimmunity via adenosine A2A receptors,” which will be published online December 19 in The Journal of Experimental Medicine, suggests that replacing the missing gut bacteria, or restoring a key metabolite called inosine, could help treat children with a rare and often fatal autoimmune disease called IPEX syndrome.
T reg cells suppress the immune system and prevent it from attacking the body’s own tissues by mistake. Defects in T reg cells therefore lead to various types of autoimmune disease. Mutations in the transcription factor Foxp3, for example, disrupt T reg function and cause IPEX syndrome. This inherited autoimmune disorder is characterized by a variety of inflammatory conditions including eczema, type I diabetes, and severe enteropathy. Without a stem cell transplant from a suitable donor, IPEX syndrome patients usually die before the age of two.
Autoimmune diseases can also be caused by changes in the gut microbiome, the population of bacteria that reside within the gastrointestinal tract. In the study, the team led by Yuying Liu and J. Marc Rhoads at The University of Texas Health Science Center at Houston McGovern Medical School find that mice carrying a mutant version of the Foxp3 gene show changes in their gut microbiome at around the same time that they develop autoimmune symptoms. In particular, the mice have lower levels of bacteria from the genus Lactobacillus. The researchers discovered that by feeding the mice with Lactobacillus reuteri, they could “reset” the gut bacterial community and reduce the levels of inflammation, significantly extending the animals’ survival.
Bacteria can secrete metabolic molecules that have large effects on their hosts. The levels of a metabolite called inosine were reduced in mice lacking Foxp3 but were restored to normal after resetting the gut microbiome with L. reuteri. The researchers found that, by binding to cell surface proteins called adenosine A2A receptors, inosine inhibits the production of Th1 and Th2 cells. These pro-inflammatory T cell types are elevated in Foxp3-deficient mice, but their numbers are diminished by treatment with either L. reuteri or inosine itself, reducing inflammation and extending the animals’ life span.
“Our findings suggest that probiotic L. reuteri, inosine, or other A2A receptor agonists could be used therapeutically to control T cell–mediated autoimmunity,” says Yuying Liu.
Conflict of interest statement: Some of the authors of this study, including Yuying Liu and J. Marc Rhoads, have a patent application pending on use of inosine and A2A agonists in IPEX syndrome.
The chronic lung inflammation that is a hallmark of cystic fibrosis, has, for the first time, been linked to a new class of bacterial enzymes that hijack the patient’s immune response and prevent the body from calling off runaway inflammation, according to a laboratory investigation led by the University of Pittsburgh School of Medicine.
The discovery, published today by the Proceedings of the National Academy of Sciences, gives scientists two avenues to explore for the creation of therapies that could interrupt or correct this interference by the opportunistic bacterium Pseudomonas aeruginosa, which disproportionately infects people with cystic fibrosis.
“There are about 30,000 patients in the U.S. with cystic fibrosis, and hundreds of thousands more with other chronic lung diseases. Once these diseases progress to the point that the patient is chronically infected with P. aeruginosa, current antimicrobial therapies are no longer effective and there are very few treatment options left,” said Jennifer M. Bomberger, Ph.D., assistant professor in Pitt’s Department of Microbiology & Molecular Genetics and senior author on the study. “Lung damage from these chronic P. aeruginosa infections, coupled with a robust but unproductive inflammatory response to the infection, will eventually lead to respiratory failure in the patient and the need for a lung transplant.”
Cystic fibrosis is caused by a genetic mutation that makes it difficult for patients to clear infections, allowing microorganisms to repeatedly infect the respiratory tract. By the time they reach adulthood, most cystic fibrosis patients are chronically infected with P. aeruginosa because this particular bacterium has an exceptional ability to outcompete other microorganisms and establish a stronghold in the lungs.
Aiding its ability to outfight other infections, P. aeruginosa thrives when the body creates an inflammatory response aimed at isolating foreign invaders and attracting white blood cells to fight them. The body’s own inflammatory response to fight infection is a major part of what actually damages a cystic fibrosis patient’s lungs to the point that they no longer function.
Bomberger’s team, in collaboration with Dean Madden, Ph.D., at the Geisel School of Medicine at Dartmouth, discovered that P. aeruginosa perpetuates inflammation by secreting an enzyme called Cif that sabotages the body’s ability to make a key molecule called a “pro-resolving lipid mediator” and put a stop to the inflammatory response it started.
The scientists confirmed this mechanism by analyzing secretions drawn from the lungs of cystic fibrosis patients seen at Children’s Hospital of Pittsburgh of UPMC and linking their findings to patient records. Patients with higher Cif levels in their lung secretions had reduced biological signaling to stop inflammation and increased levels of IL-8, a marker for inflammation. Increased Cif levels also correlated with reduced lung function, which leads to disease progression in patients.
Previous studies in mice indicated that artificially boosting the levels of the pro-resolving lipid mediator reduces the inflammatory response and promotes clearance of P. aeruginosa in a pneumonia model. Bomberger and Madden, in collaboration with colleagues at the University of California, Davis, are exploring an alternative strategy to inhibit Cif activity, stopping the problem before it begins.
“It will be key to devise a way to remove P. aeruginosa’s ability to capitalize on the body’s natural inflammatory response, without eliminating that response,” said Bomberger. “Inflammation is happening for a reason—to clear infection. We just need it to temper the response when it is not effectively doing its job or is no longer needed.”
Personalized vaccine created from patients’ own immune cells and cancer cells in 17-patient trial.
Newswise — BOSTON – A personalized cancer vaccine markedly improved outcomes for patients suffering from acute myeloid leukemia (AML), a potentially lethal blood cancer, in a clinical trial led by investigators at Beth Israel Deaconess Medical Center (BIDMC). The product of a long-term collaboration among investigators at the Cancer Center at BIDMC and Dana-Farber Cancer Institute, the vaccine stimulated powerful immune responses against AML cells and resulted in protection from relapse in a majority of patients, the team of researchers reported today in Science Translational Medicine.
“Immunotherapy strategies leverage the body’s own defense systems to fight cancer cells,” said senior author David Avigan, MD, Chief, Section of Hematological Malignancies and Director of the Cancer Vaccine Program at the BIDMC Cancer Center and Professor of Medicine at Harvard Medical School. “By creating a personalized vaccine, we use the power of the immune system to selectively target each patient’s cancer and avoid the side effects of chemotherapy.”
Patients with AML may achieve remission following standard chemotherapy, yet relapse is common, and most patients ultimately succumb to the disease. In this study, the team of collaborators from BIDMC and Dana-Farber generated personalized vaccines for 17 patients with AML who were in remission after undergoing standard chemotherapy.
Despite an average age of 63, more than 70 percent of trial participants remained in remission at an average follow-up period of more than four years. After receiving a series of injections of the vaccine, patients demonstrated an increase in the number of leukemia-specific T cells in the blood and bone marrow. T cells are immune cells critical to the body’s ability to recognize and remember pathogens like viruses, or in this case, cancer cells. Present only in low numbers prior to vaccination, T cells recognizing AML cells were expanded after vaccination, potentially providing long-term protection against the leukemia.
“With the vaccine, we use the immune system to target the whole tumor including cells that may be resistant to chemotherapy,” stated lead author Jacalyn Rosenblatt, MD, Co-Director of the Cancer Vaccine Program at the BIDMC Cancer Center and Associate Professor of Medicine at Harvard Medical School. “We were really excited to see that the vaccine generated a broad and durable immune response without significant side effects.”
This vaccine platform has been the product of collaboration among BIDMC and Dana-Farber investigators, including the initial seminal work done by Donald W. Kufe, MD, Distinguished Physician at Dana-Farber, subsequent development and clinical translation by Kufe, Rosenblatt and Avigan, and the contributions of clinical investigators including Richard Stone, MD, Chief of the Adult Leukemia Program at Dana-Farber, and Lynne Uhl, MD, Director of Transfusion Medicine at BIDMC.
“The development of this personalized vaccine by our team was based on the premise that effective treatment of established cancers would require the induction of immunity against multiple antigens, including neoantigens, specifically expressed by the patient’s own cancer cells,” stated co-author Donald W. Kufe, MD.
Based on these encouraging results, researchers are also testing this vaccine approach in other types of cancers. Avigan and colleagues are leading a national study to test the effectiveness of the vaccine in patients with multiple myeloma, another common blood cancer. Conducted under the auspices of the NIH-sponsored Clinical Trials Network, this first-of-its-kind endeavor brings together 15 leading cancer centers. Of note, the unique research effort takes an open-source approach, in which participating sites were trained in vaccine production at BIDMC and will work together to bring this therapy to patients nationwide.