Scientists confirm correlation between malignant hyperthermia and exertional heat stroke

New research published online in The FASEB Journal may ultimately help athletes and trainers better understand who may be more at risk for heat stroke. In the report, scientists use animals to show that there is a link between the susceptibility to malignant hyperthermia (MH) and exertional heat stroke.

“Global warming and increasing frequency of heat waves, which are particularly dangerous in large urban areas, in future years will represent a reason of concern for human health,” said Feliciano Protasi, Ph.D., a researcher involved in the work at the Department of Neuroscience, Imaging and Clinical Sciences, University G. d’Annunzio, Chieti, Italy. “However, in spite of the increased incidence, severity and life-threatening nature of heat stroke, there are currently no safe and effective drug interventions to protect or reverse this deadly syndrome. We hope that our study will contribute to develop preventive measures and/or acute treatments for heat stroke caused by environmental heat and physical exertion.”

Scientists used three groups of mice to reach their conclusion. The first two groups (RYR1Y522S/WT and CASQ1-null mice) had altered genes that made them susceptible to lethal hyperthermic crises when exposed to anesthetics, while the third group was normal (wild-type mice). When the three sets of mice were exposed to a protocol of exertional stress (incremental running at 34 degrees Celsius and 40 percent humidity) the MH-susceptible mice (but not the normal mice) suffered lethal overheating episodes.

“This work addresses a dangerous, often lethal, physiological maladjustment that animals and humans can undergo,” said Thoru Pederson, Ph.D., Editor-in-Chief of The FASEB Journal. “The door now stands open to finding effective preventative drugs.”

Maternal High-Fat Diet May Increase Offspring Risk for Liver Disease

Research could uncover who is most at risk for nonalcoholic fatty liver disease and lead to new treatments for this increasingly common condition

Nonalcoholic fatty liver disease, a condition where fat builds up in the liver, is now the most common chronic liver disease diagnosed in adults and children. Although the disease is linked with obesity, scientists don’t fully understand why some people develop it and others don’t. Findings from a new mouse study suggest that exposure to a high-fat diet in the womb and immediately after birth may change the liver in a way that promotes more rapid progression of nonalcoholic fatty liver disease later in life.

Michael Thompson, MD, PhD, pediatric endocrinology fellow at Nationwide Children’s Hospital, will present the new research at the American Society for Investigative Pathology annual meeting during the Experimental Biology 2017 meeting, to be held April 22–26 in Chicago.

“Complications of obesity are a significant cost burden for the medical system, especially given the prevalence of obesity,” said Thompson. “Understanding how maternal exposures impact obesity-related disease such as nonalcoholic fatty liver disease will allow us to develop lower cost preventative therapies to utilize up front rather than awaiting complications down the road.”

In the new study, the researchers found that the offspring of pregnant mice that consumed a high-fat diet developed liver fibrosis, a type of tissue scarring that is a sign that more serious disease will develop. The offspring weaned to a low-fat diet after maternal high-fat diet exposure developed fibrosis in adulthood. The livers of these mice also had signs of fat accumulation and inflammation.

The findings showed that developmental exposure to a high-fat diet can produce changes in the liver that last into adulthood, even with consumption of a low-fat diet after birth. These findings could have implications for people who are not obese themselves but who had obese mothers.

Additional analysis showed that bile acid levels and genes involved in bile-acid regulation were changed in the offspring exposed to the maternal high-fat diet. This finding suggests that the offspring may have a liver disease called cholestasis, which occurs when the normal flow of bile is impaired.

“If human offspring from obese mothers have a similar risk for developing fibrosis as we see in mice, we may be able to predict who is going to develop more serious disease,” said Thompson.  “Knowing who is most at risk for more serious disease will guide us on which patients should be treated more aggressively. Furthermore, understanding the biological mechanisms involved in this increased risk could lead to preventative therapies.”

The researchers are now working to further understand the mechanisms involved in the risk for disease progression. They also plan to use their mouse model of developmental high-fat diet exposure to evaluate preventative therapies that could be administered during pregnancy or to the offspring.

Lysosomes in Healthy Neurons and in Neurons with Juvenile Batten Disease

Researchers at Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute at Texas Children’s Hospital and King’s College London have discovered a treatment that improves the neurological symptoms in a mouse model of juvenile Batten disease. This discovery brings hope to patients and families affected by the disease that a treatment might be available in the future. The study appears in Nature Communications.

“Patients with juvenile Batten disease are born healthy and reach the expected developmental milestones of the first 4 to 6 years of age,” said senior author Dr. Marco Sardiello, assistant professor of molecular and human genetics at Baylor. “Then, these children progressively regress their developmental achievements; they gradually lose their vision and develop intellectual and motor disabilities, changes in behavior and speech difficulties. Most people with this condition live into their 20s or 30s. This inherited, rare disease has no cure or treatment other than palliative care.”

“As we started this project, patients and families affected by this condition visited us in the laboratory,” said first author Dr. Michela Palmieri, who was a postdoctoral fellow in the Sardiello lab during this project and currently is at the San Raffaele Scientific Institute in Milan, Italy. “We were deeply affected by our interactions with the patients and their families and this further motivated us to pursue this research with the hope that maybe one day it will lead to a treatment that will improve the lives of people affected by this condition.”

Juvenile Batten disease, a problem with cellular waste management

Like a large dynamic city, a cell carries out many activities that generate waste. Waste needs to be disposed of properly in order for the city to continue its activities without interruption. If waste management fails, waste progressively accumulates and eventually leads to interruption and paralysis of the activities of the city. Something similar happens in cells when cellular waste is not discarded.

The lysosomes are the structures in charge of clearing the waste produced by the cell’s regular functions. Lysosomes are sacs inside all cells containing enzymes that degrade cellular waste into its constituent components, which the cell can recycle or discard. When lysosomes fail and cellular waste accumulates, disease follows. Although all types of cells can be affected by defects in lysosomal waste processing and cellular waste accumulation, brain cells – neurons – are particularly susceptible.

“In juvenile Batten disease, one of nearly 50 human lysosomal storage disorders, the function of brain cells is progressively affected by the accumulation of cellular waste,” Sardiello said. “This accumulation leads to perturbation of many cellular processes, cell death and progressive regression of motor, physical and intellectual abilities.”

A novel approach to finding a treatment

“A few years back we discovered a protein in cells called TFEB, a master transcription factor that stimulates the cell to produce more lysosomes and degrade cellular waste more effectively,” said Sardiello. “So we thought about counteracting the accumulation of cellular waste in Batten disease by acting on TFEB.”

“We and others had found that enhancing the activity of TFEB genetically can help counter the accumulation of cellular waste in different diseases,” Sardiello said. “What was missing was a way to activate TFEB with a drug that in the future could be put in a pill to treat the condition. We focused on investigating how to activate TFEB pharmacologically.”

“We discovered that TFEB is under the control of another molecule called Akt, which is a kinase, a protein that can modify other proteins,” said Palmieri. “Akt has been studied in detail. There are drugs available that can modulate the activity of Akt.”

The researchers discovered that Akt modifies TFEB by adding a chemical group, a phosphate, to it. This chemical modification inactivates TFEB.

“We wanted to inhibit Akt to keep TFEB more active,” said Palmieri. “We discovered that the sugar trehalose is able to do this job.”

Testing a treatment for juvenile Batten disease in a mouse model of the condition

The scientists tested the effect of trehalose in a mouse model of juvenile Batten disease.

“We dissolved trehalose in drinking water and gave it to mice that model juvenile Batten disease,” said Sardiello. “Then, over time we examined the mice’s brain cells under the microscope. We found that the continuous administration of trehalose inhibits Akt and activates TFEB in the brains of the mice. More active TFEB meant more lysosomes in the brain and increased lysosomal activity, followed by decreased accumulation of the storage material and reduced tissue inflammation, which is one of the main features of this disease in people, and reduced neurodegeneration. These changes resulted in the mice living significantly longer. This is a good start toward finding a treatment for people with this disease.”

“We are very excited that these findings put research a step closer to understanding the mechanisms that underlie human lysosomal storage diseases,” said Palmieri. “We hope that our research will help us design treatments to counteract this and other human diseases with a pathological storage component, such as Alzheimer’s, Huntington’s and Parkinson’s diseases, and hopefully ameliorate the symptoms or reduce the progression of the disease for those affected.”

Naturally Occurring Mechanism of Cancer Drug-Resistance May Itself Be a Treatment Target

The use of proteasome inhibitors to treat cancer has been greatly limited by the ability of cancer cells to develop resistance to these drugs. But Whitehead Institute researchers have found a mechanism underlying this resistance—a mechanism that naturally occurs in many diverse cancer types and that may expose vulnerabilities to drugs that spur the natural cell-death process.

This finding—which also identifies a biomarker that can be used to gain a deeper understanding of the proteasome inhibitor-resistant state— is reported in the Proceedings of the National Academy of Sciences (PNAS) in an article entitled, Suppression of 19S proteasome subunits marks emergence of an altered cell state in diverse cancers.

Proteasomes are large protein complexes that mediate protein degradation and play a crucial role in maintaining protein equilibrium within the cell. When cells become cancerous, tremendous stresses are placed on the cellular machinery responsible for maintaining protein equilibrium—and that machinery is the target of anti-cancer drugs called proteasome inhibitors. Although proteasome inhibitors are very efficient in selective killing of cancer tumor cells grown in a dish (in-vitro), their success in the clinic has largely been undermined by the development of resistance—mechanisms of which are poorly understood.

“However, recently, we discovered a counterintuitive mechanism by which cells can acquire resistance to proteasome inhibitors in vitro,” explains Peter Tsvetkov, lead author of the PNAS article and a post-doctoral researcher at Whitehead Institute. “Now, in this report, we show that this mechanism is at work in many human cancers. Moreover, we have determined that the mechanism is symptomatic of a broadly altered state in the cell, with a unique gene signature and newly exposed vulnerabilities that can be targeted with existing drugs.” Notably, the mechanism was clearly associated with poor outcome in patients with the blood cancer myeloma, where proteasome inhibitors are a mainstay of treatment.

Analyzing data from thousands of cancer lines and tumors, the researchers found that those demonstrating resistance to proteasome inhibitor drugs were marked by suppressed expression of one or more of the cells’ proteasome cap subunits (which are a subsets of the larger proteasome). Suppressing the expression of even one of the many subunits making up the cap will impair the assembly of the whole cap, resulting in a proteasome-inhibitor resistant state. “This fact reinforces just how complex the mechanisms of resistance to chemotherapy can be,” says Luke Whitesell, a senior author of the PNAS paper and senior scientist at Whitehead Institute

Nevertheless, this new report reveals a strategy to address such resistance which may have broad utility. The researchers found that, beyond conferring resistance to proteasome inhibitors, the suppressed expression of proteasome subunits reflects a broad remodeling of the cell’s gene signature. Furthermore, this can also serve as a biomarker to stratify patients for treatment. “That signature marks a heritably altered and therapeutically relevant state in diverse cancers—a state that may expose vulnerability to specific drugs that are already in use in the clinic,” Tsvetkov observes. “Cancers can achieve this resistance by multiple mechanisms, genetic or epigenetic. But these findings point us to new strategies and novel compounds that can be developed as treatments that will be more effective for an array of cancer types because they are less susceptible to the emergence of resistance.”

Engineers design a new weapon against bacteria

Over the past few decades, many bacteria have become resistant to existing antibiotics, and few new drugs have emerged. A recent study from a U.K. commission on antimicrobial resistance estimated that by 2050, antibiotic-resistant bacterial infections will kill 10 million people per year, if no new drugs are developed.

To help rebuild the arsenal against infectious diseases, many scientists are turning toward naturally occurring proteins known as antimicrobial peptides, which can kill not only bacteria but other microbes such as viruses and fungi. A team of researchers at MIT, the University of Brasilia, and the University of British Columbia has now engineered an antimicrobial peptide that can destroy many types of bacteria, including some that are resistant to most antibiotics.

“One of our main goals is to provide solutions to try to combat antibiotic resistance,” says MIT postdoc Cesar de la Fuente. “This peptide is exciting in the sense that it provides a new alternative for treating these infections, which are predicted to kill more people annually than any other cause of death in our society, including cancer.”

De la Fuente is the corresponding author of the new study, and one of its lead authors along with Osmar Silva, a postdoc at the University of Brasilia, and Evan Haney, a postdoc at the University of British Columbia. Timothy Lu, an MIT associate professor of electrical engineering and computer science, and of biological engineering, is also an author of the paper, which appears in the Nov. 2 issue of Scientific Reports.

Improving on nature

Antimicrobial peptides, produced by all living organisms as part of their immune defenses, kill microbes in several different ways. First, they poke holes in the invaders’ cell membranes. Once inside, they can disrupt several cellular targets, including DNA, RNA, and proteins.

These peptides also have another critical ability that sets them apart from traditional antibiotics: They can recruit the host’s immune system, summoning cells called leukocytes that secrete chemicals that help kill the invading microbes.

Scientists have been working for several years to try to adapt these peptides as alternatives to antibiotics, as bacteria become resistant to existing drugs. Naturally occurring peptides can be composed of 20 different amino acids, so there is a great deal of possible variation in their sequences.

“You can tailor their sequences in such a way that you can tune them for specific functions,” de la Fuente says. “We have the computational power to try to generate therapeutics that can make it to the clinic and have an impact on society.”

In this study, the researchers began with a naturally occurring antimicrobial peptide called clavanin-A, which was originally isolated from a marine animal known as a tunicate. The original form of the peptide kills many types of bacteria, but the researchers decided to try to engineer it to make it even more effective.

Antimicrobial peptides have a positively charged region that allows them to poke through bacterial cell membranes, and a hydrophobic stretch that enables interaction with and translocation into membranes. The researchers decided to add a sequence of five amino acids that would make the peptides even more hydrophobic, in hopes that it would improve their killing ability.

This new peptide, which they called clavanin-MO, was very potent against many bacterial strains. In tests in mice, the researchers found that it could kill strains of Escherichia coli and Staphylococcus aureus that are resistant to most antibiotics.

Suppressing sepsis

Another key advantage of these peptides is that while they recruit immune cells to combat the infection, they also suppress the overactive inflammatory response that can cause sepsis, a life threatening condition.

“In this single molecule, you have a synthetic peptide that can kill microbes — both susceptible and drug-resistant — and at the same time can act as an anti-inflammatory mediator and enhance protective immunity,” de la Fuente says.

The researchers also found that these peptides can destroy certain biofilms, which are thin layers of bacterial cells that form on surfaces. That raises the possibility of using them to treat infections caused by biofilms, such as the Pseudomonas aeruginosa infections that often affect the lungs of cystic fibrosis patients. Or, they could be embedded into surfaces such as tabletops to make them resistant to microbial growth.

Other possible applications for these peptides include antimicrobial coatings for catheters, or ointments that could be used to treat skin infections caused by Staphylococcus aureus or other bacteria.

If these peptides are developed for therapeutic use, the researchers anticipate that they could be used either in stand-alone therapy or together with traditional antibiotics, which would make it more difficult for bacteria to evolve drug resistance. The researchers are now investigating what makes the engineered peptides more effective than the naturally occurring ones, with hopes of making them even better.

Heart disease, leukemia linked to dysfunction in nucleus

We put things into a container to keep them organized and safe. In cells, the nucleus has a similar role: keeping DNA protected and intact within an enveloping membrane. But a new study by Salk Institute scientists, detailed in the November 2 issue of Genes & Development, reveals that this cellular container acts on its contents to influence gene expression.

“Our research shows that, far from being a passive enclosure as many biologists have thought, the nuclear membrane is an active regulatory structure,” says Salk Professor Martin Hetzer, who is also holder of the Jesse and Caryl Philips Foundation chair. “Not only does it interact with portions of the genome to drive gene expression, but it can also contribute to disease processes when components are faulty.”

Using a suite of molecular biology technologies, the Salk team discovered that two proteins, which sit in the nuclear envelope, together with the membrane-spanning complexes they form, actively associate with stretches of DNA to trigger expression of key genes. Better understanding these higher-level functions could provide insight into diseases that appear to be related to dysfunctional nuclear membrane components, such as leukemia, heart disease and aging disorders.

Historically, the nuclear membrane’s main purpose was thought to be keeping the contents of the nucleus physically separated from the rest of the cell. Complexes of at least thirty different proteins, called nucleoporins, form gateways (pores) in the membrane, controlling what goes in or out. But as the Hetzer lab’s work on nucleoporins shows, these nuclear pore complexes (NPCs), beyond being mere gateways into the nucleus, have surprising regulatory effects on the DNA inside.

“Discovering that key regulatory regions of the genome are actually positioned at nuclear pores was very unexpected,” says Arkaitz Ibarra, a Salk staff scientist and first author of the paper. “And even more importantly, nuclear pore proteins are critical for the function of those genomic sites.”

Curious about all the regions of DNA with which nucleoporins potentially interact, the team turned to a human bone cancer cell line. The scientists used a molecular biology technique called DamID to pinpoint where two nucleoporins, Nup153 and Nup93, came into contact with the genome. Then they used several other sequencing techniques to understand which genes were being affected in those regions, and how.

The Salk team discovered that Nup153 and Nup93 interacted with stretches of the genome called super-enhancers, which are known to help determine cell identity. Since every cell in our body has the same DNA, what makes a muscle cell different from a liver cell or a nerve cell is which particular genes are turned on, or expressed, within that cell. In the Salk study, the presence of Nup153 and Nup93 was found to regulate expression of super-enhancer driven genes and experiments that silenced either protein resulted in abnormal gene expression from these regions. Further experiments in a lung cancer cell line validated the bone cancer line results: Nucleoporins in the NPC were found to interact with multiple super-enhancer regions to drive gene expression, while experiments that altered the NPC proteins made related gene expression faulty, even though the proteins still performed their primary role as gatekeepers in the cell membrane.

“It was incredible to find that we could perturb the proteins without affecting their gateway role, but still have nearby gene expression go awry,” says Ibarra.

The results bolster other work indicating that problems with the nuclear membrane play a role in heart disease, leukemia and progeria, a rare premature aging syndrome.

“People have thought the nuclear membrane is just a protective barrier, which is maybe the reason why it evolved in the first place. But there are many more regulatory levels that we don’t understand. And it’s such an important area because so far, every membrane protein that has been studied and found to be mutated or mis-localized, seems to cause a human disease,” says Hetzer.

Reactome Announces Annotation And Release Of 10,000th Human Protein

The European Bioinformatics Institute (EMBL-EBI), the New York University School of Medicine and the Ontario Institute for Cancer Research (OICR) today announced a major milestone in the Reactome project: the annotation and release of its 10,000th human protein, making it the most comprehensive open access pathway knowledgebase available to the scientific community.

Reactome (www.reactome.org) relates human genes, proteins and other biomolecules to the biological pathways and processes in which they participate. It is a key resource for the biomedical research community, and is widely used by scientists around the world to interpret high-throughput experiments in genetics, genomics and proteomics.

The human genome contains roughly 20,000 protein-coding genes in total, so the annotation of the 10,000th protein means that Reactome now covers half of the protein-coding portion of the genome.

“We are pleased to reach this milestone and to share the results with the research community,” said Dr. Lincoln Stein, Interim Scientific Director of OICR, Director of OICR’s Informatics and Bio-computing Program and a Principal Investigator on the Reactome project. “Today’s release, which is the result of over a decade of hard work and collaboration, will help researchers in their effort to better understand how genomic variation leads to diseases like cancer, to develop methods to detect those diseases at an earlier stage and to treat patients more effectively.”

Henning Hermjakob at EMBL–EBI and Peter D’Eustachio at the New York University School of Medicine are also Principal Investigators on the project.

By relating genes and proteins to normal and abnormal biological pathways, Reactome provides sophisticated tools for identifying patterns in large datasets. For example, researchers can explore an experiment in Reactome that identifies thousands of genes involved in a disease, and reduce the data to a more targeted set of pathways for further study. By combining the resulting dataset with other resources, they are well placed to identify drugs and protein targets that might reverse undesirable pathway alterations, or discover ways to diagnose the disease at an early stage.

Via its website, online tools, and specialized visualization and analysis applications, Reactome has been incorporated into more than 400 third-party genome analysis tools, and has been cited more than 4,000 times in the scientific literature.

“Congratulations to the Reactome team on this major milestone,” said Reza Moridi, Minister of Research, Innovation and Science. “Through international collaborations such as this, Ontario researchers are making great strides in fighting disease on a global scale and I look forward to witnessing ongoing success with transformative discoveries that impact the lives of Ontarians every day.”

Closing In On Biomarkers For Suicidal Behavior

An enzyme called ACMSD—part of a chain of biochemical reactions called the kynurenine pathway, activated by inflammation—could become an important target for new drugs aimed at preventing suicide.

The enzyme shows reduced activity in people who have tried to kill themselves, according to astudy published online Aug. 2, 2016, in Translational Psychiatry. And downstream effects of the sluggish enzyme—namely, abnormal levels of two acids in the body—could potentially be measured in blood tests to help identify patients at high risk, say the researchers.

The study was conducted with Swedish patients but involved collaborators in three other countries, including in the U.S. at VA’s Rocky Mountain Mental Illness Research, Education, and Clinical Center (MIRECC) for Suicide Prevention in Denver, and at the Van Andel Research Institute in Michigan.

“We now want to find out if these changes are only seen in individuals with suicidal thoughts or if patients with severe depression also exhibit this. We also want to develop drugs that might activate the enzyme ACMSD and thus restore balance between quinolinic and picolinic acid,” said Dr. Sophie Erhardt of the Karolinska Institutet in Stockholm, one of the leaders of the study.

Senior author on the study was Dr. Lena Brundin at Van Andel. Representing VA was Dr. Teodor Postolache, a clinical and research psychiatrist with VA’s Rocky Mountain MIRECC for Suicide Prevention. Postolache is also an investigator with VA’s MIRECC in Baltimore, and a professor at the University of Maryland School of Medicine.

The immune system and mental health

An increasing body of evidence in recent years has implicated the immune system—particularly inflammation—as a possible contributing factor in both depression and suicidal behavior. Inflammation is one way the body responds to stress. But the link is complex, and researchers are still far from grasping exactly how the pieces fit together, and whether the findings can be used clinically to advance suicide prevention.

The new study, conducted in several phases, involved more than 300 Swedish patients and other volunteers. The researchers took samples of blood and cerebrospinal fluid from those who had attempted suicide, immediately after the suicidal episode and at intervals thereafter, and compared them with samples from healthy controls.

In the suicidal patients, the ratio between picolinic and quinolinic acid was out of whack—too little of the former, too much of the latter. Picolinic acid is protective, whereas quinolinic acid is toxic to the brain and nervous system.

The changes were most pronounced in the cerebrospinal fluid, the clear liquid that cushions the brain and spinal cord. The abnormal levels persisted at least two years in repeated tests of the fluid. The changes also showed up in blood tests, albeit less markedly. But blood tests are much easier to perform than spinal taps, so they could represent a more practical clinical option.

Gene tests confirm results

The researchers knew from past studies that ACSMD modulates the levels of the two acids. They confirmed the link in the current study though a genetic analysis. They found that a particular variant of the ACSMD gene was more prevalent in suicide attempters, and was associated with increased quinolinic acid.

Targeting ACSMD with a drug to boost its activity could, in theory, normalize the ratio between the two acids it affects, say the researchers.

But the study wasn’t designed to show a direct causal relationship between ACSMD activity and suicide risk. So it’s not clear that raising ACSMD activity and restoring the picolinic-quinolinic ratio would actually curb suicidal behavior.

The next step in exploring that, say the researchers, would be lab tests with an animal model of depression. Lab animals that exhibit traits typical of depression, such as lack of interest in normal activities, as well as traits such as impulsivity, are commonly studied by scientists looking at suicidal behavior.

Combating inflammation over long term may be best

Further research may also shed light on issues of timing. To the extent that inflammation does drive suicidal behavior, it could be a problem that is years in the making, and that demands long-range strategies.

Dr. John Krystal, a psychiatry researcher with VA and Yale School of Medicine, is the editor of the journal Biological Psychiatry. He was quoted in response to a study in the journal last year that showed increased levels of inflammation-causing immune chemicals called cytokines in suicidal patients:

“Inflammation affects every organ in the body,” noted Krystal. “It is increasingly evident that we need to take a long-term perspective on the effects of inflammation on the brain. The path to preventing suicide may be to intervene early in long-term processes that increase the risk for suicide, rather than to focus solely on the elusive short-term predictors of suicide.”

Potential therapeutic target for Huntington’s disease

There is new hope in the fight against Huntington’s disease. Scientists at the Gladstone Institutes discovered that changing a specific part of the huntingtin protein prevented the loss of critical brain cells and protected against behavioral symptoms in a mouse model of the disease.

Huntington’s disease causes jerky, uncoordinated movements and a loss of control of motor function. It also results in deficits in learning and memory, as well as personality changes, such as dementia, depression, and aggression. Huntington’s is ultimately fatal, and there are no treatments to stop or slow its progression.

The disease is linked to a mutation in the Huntingtin gene, which causes a protein of the same name to fold up incorrectly like misshapen origami. Neurons cannot get rid of the misfolded protein, so it builds up in the brain, wreaking havoc in the cells.

In the new study, published in the Journal of Clinical Investigation, scientists in the laboratory of Steve Finkbeiner, MD, PhD, showed that modifying the huntingtin protein through a process called phosphorylation can actually make the protein less toxic and allows cells to eliminate it more easily. In fact, phosphorylating a specific spot on the protein called S421 protected a mouse model of Huntington’s from developing symptoms of the disease.

“I was shocked at the profound effect phosphorylation had on the Huntington’s model mice,” said first author Ian Kratter, MD, PhD, a former graduate student at Gladstone and the University of California, San Francisco (UCSF). “They showed few signs of the motor dysfunction, depression, or anxiety that are characteristic of the disease. In most of our tests, they were virtually indistinguishable from healthy mice.”

The mice were also protected against neuron death, particularly in the striatum, the movement and reward center of the brain that is first affected in Huntington’s disease. The scientists think that phosphorylation enables neurons to remove more of the harmful protein so it does not accumulate and damage the cell.

“Phosphorylation helps control how proteins fold and the systems in cells that clear proteins,” explained Finkbeiner, who is a senior investigator at Gladstone. “This is exciting, because a lot of the work we’ve done points to these protein removal pathways as being important not only for Huntington’s disease, but also for other neurodegenerative disorders. Understanding how phosphorylation links to these pathways could help treat several different brain diseases.”

The researchers are now exploring ways to mimic the effects of phosphorylation with a drug.

Why do aged muscles heal slowly?

As we age, the function and regenerative abilities of skeletal muscles deteriorate, which means it is difficult for the elderly to recover from injury or surgery. New work from Carnegie‘s Michelle Rozo, Liangji Li, and Chen-Ming Fan demonstrates that a protein called b1-integrin is crucial for muscle regeneration. Their findings, published by Nature Medicine, provide a promising target for therapeutic intervention to combat muscle aging or disease.

Muscle stem cells are the primary source of muscle regeneration after injury. These specialized adult stem cells lie dormant in the muscle tissue–off to the side of the individual muscle fibers, which is why they were originally dubbed satellite cells. When muscle fibers are damaged, they activate and proliferate. Most of the new cells go on to make new muscle fibers and restore muscle function. Some return to dormancy, which allows the muscle to keep repairing itself over and over again.

Rozo, the lead author, determined that the function of integrins (or, more specifically, the protein called β1-integrin) is absolutely crucial for maintaining the cycle of hibernation, activation, proliferation, and then return to hibernation, in muscle stem cells. Integrins are proteins that ‘integrate’ the outside to the inside of the cell, providing a connection to the immediate external environment, and without them, almost every stage of the regenerative process is disrupted.

The team theorized that defects in β1-integrin likely contribute to phenomena like aging, which is associated with reduced muscle stem cell function and decreased quantities of muscle stem cells. This means that healing after injury or surgery is very slow, which can cause a long period of immobility and an accompanying loss of muscle mass.

“Inefficient muscular healing in the elderly is a significant clinical problem and therapeutic approaches are much needed, especially given the aging population-and I am including myself in this population,” Fan explained. “Finding a way to target muscle stem cells could greatly improve muscle renewal in older individuals.”

Rozo and Li determined that the function of β1-integrin is diminished in aged muscle stem cells. Furthermore, when they artificially activated integrin in mice with aged muscles, their regenerative abilities were restored to youthful levels. Importantly, improvement in regeneration, strength, and function were also seen when this treatment was applied to animals with muscular dystrophy, underscoring its potential importance for the treatment of muscle disorders.

Muscle stem cells use b1-integrin to interact with many other proteins in the muscle external environment. Among these many proteins, they found a clue that one called fibronectin might be most relevant. To connect b1-integrin to fibronectin, they teamed up with another group led by scientists from the Nestlé Institute of Health Sciences, in addition to researchers from the EPFL EDBB Doctoral Program, the Leibniz Institute for Age Research, the Ottawa Hospital Research Institute, and the Max Planck Institute of Biochemistry.

They discovered that aged muscles contain substantially reduced levels of fibronectin compared to young muscles. Like b1-integrin, eliminating fibronectin from young muscles makes them appear as if they were old, and restoring fibronectin to aged muscle tissue restores muscle regeneration to youthful levels. Their joint efforts demonstrated a strong link between b1-integrin, fibronectin and muscle stem cell regeneration, which is the subject of a second paper, also published by Nature Medicine in the same issue.

“Taken together, our results show that aged muscle stem cells with compromised b1-integrin activity and aged muscles with insufficient amount of fibronectin both root causes of muscle aging. This makes b1-integrin and fibronectin very promising therapeutic targets,” Fan said.

UMN researchers find distinct differences in structure, features of retroviruses

In the most comprehensive study of its kind, researchers in the Institute for Molecular Virology and School of Dentistry at the University of Minnesota report that most types of retroviruses have distinct, non-identical virus structures.

Researchers analyzed seven different retroviruses including two types of HIV as well as HTLV-1, a virus that causes T-cell leukemia. They also examined retroviruses that infect birds, mice, chimpanzees and fish, that can cause cancer or immunodeficiency.

“Each kind of retrovirus has distinct structural features and each assembles virus particles differently,” said Louis Mansky, Ph.D., director of the Institute for Molecular Virology, who is also a member of the Masonic Cancer Center. “Most researchers assume that all retroviruses are just like HIV, but they’re not. We cannot take a one-size-fits-all approach when studying retroviruses and discovering new strategies for antiviral treatments or vaccines.”

Mansky’s team looked at the behavior of retrovirus Gag proteins, which drive retrovirus particle formation. Once the virus enters a cell, reverse transcriptase converts the viral RNA to DNA, which subsequently creates the Gag protein.

Understanding the nature of Gag protein interactions with one another and how the structures form will help scientists better understand how and why the virus works. It will also help identify ways to target the virus and prevent it from infecting a cell in the first place.

The study examined virus-like particle size, cellular distribution and basic morphological features through three distinct microscopy techniques.

The team noted that:

– HIV-1 and HIV-2 have Gag proteins that assemble retrovirus-like particles with distinct structures and sizes, which implies that differences exist in how the two HIV types form new virus particles. – HIV and HTLV-1 particles are quite distinct from one another in appearance, which also suggests fundamental differences in virus particle assembly.

“We found significant differences among the retroviruses,” said Jessica Martin, senior Ph.D. student in the Department of Pharmacology and lead author on the study. “A parallel comparative study evaluating retroviral Gag proteins and virus particle intermediates of this size and scope has never been done before.”

The team was surprised to find that one of the retroviruses, walleye dermal sarcoma virus (WDSV), did not readily produce virus particles.The disease can affect anything from 1-30 percent of walleye in a population, depending on the location. This research could help aquatic scientists better understand how to control the disease.

“Our study helps to highlight the importance of serendipity of basic science research,” Mansky said. “We set out to learn more about the differences among two important human retroviruses, namely HIV and HTLV, which we did, but our findings also shed light on important differences among all kinds of retroviruses that could inform not only the treatment of human viral diseases but could also impact aquatic health in fisheries.”

The study findings will help serve as a foundation for studying differences among retroviruses, including HIV.

“The scientific community can build off of our findings to develop new antiviral treatments, and hopefully determine how to stop these viruses from causing deadly diseases in humans such as cancer and AIDS,” Mansky said.

New anti-cancer strategy mobilizes both innate and adaptive immune response

Though a variety of immunotherapy-based strategies are being used against cancer, they are often hindered by the inability of the immune response to enter the immunosuppressive tumor microenvironment and to effectively mount a response to cancer cells. Now, scientists from the RIKEN Center for Integrative Medical Sciences have developed a new vaccine that involves injecting cells that have been modified so that they can stimulate both an innate immune response and the more specific adaptive response, which allows the body to keep memories and attack new tumor cells as they form. In the study published in Cancer Research, they found that the vaccine made it possible for killer CD8+T-cells–important players in the immune response against cancer–to enter the tumor microenvironment and target cancerous cells.

According to Shin-ichiro Fujii, leader of the Laboratory for Immunotherapy, who led the study, “Cancer cells have different sensitivities to the innate or adaptive response, so it important to target both in order to eradicate it. We have developed a special type of modified cell, called aAVC, which we found can do this.”

The aAVC cells are not taken from the subject’s own body but are foreign cells. The cells are modified by adding a natural killer t-cell ligand, which permits them to stimulate natural killer T-cells, along with an antigen associated with a cancer. The group found that when these cells are activated, they in turn promote the maturation of dendritic cells, which act as coordinators of the innate and acquired response. Dendritic cells are key because they allow the activation of immune memory, where the body remembers and responds to a threat even years later.

To find whether it worked in actual bodies, they conducted experiments in mice with a virulent form of melanoma that also expresses a model antigen called OVA. Tests in mice showed, moreover, that aggressive tumors could be shrunken by vaccinating the animals with aAVC cells that were programmed to display OVA antigen. Following the treatment, the tumors in the treated animals were smaller and necrotic in the interior–a sign that the tumor was being attacked by the killer CD8+T-cells.

Fujii continues, “We were interesting in finding a mechanism, and were able to understand that the aAVC treatment led to the development of blood vessels in the tumors that expressed a pair of important adhesion molecules, ICAM-1 and VCAM-1, that are not normally expressed in tumors. This allowed the killer CD8+T cells to penetrate into the tumor.”

They also found that in animals that had undergone the treatment, cancer cells injected even a year later were eliminated. “This indicates,” says Fujii, “that we have successfully created an immune memory that remembers the tumor and attacks it even later.”

Looking to the future, Fujii says, “Our therapy with aAVC is promising because typical immunotherapies have to be tailor-made with the patient’s own cells. In our case we use foreign cells, so they can be made with a stable quality. Because we found that our treatment can lead to the maturation of dendritic cells, immunotherapy can move to local treatment to more systemic treatment based on immune memory.”

Get a clue: Biochemist studies fruit fly to understand Parkinson’s disease, muscle wasting

The fruit fly may help us be less clueless about human muscle development and Parkinson’s disease.

Erika Geisbrecht, Kansas State University associate professor of biochemistry and molecular biophysics, is studying the fruit fly, or Drosophila melanogaster, to understand a gene called clueless, or clu. Geisbrecht and her research team have found a connection between clu and genes that cause Parkinson’s disease.

Geisbrecht’s team is among the first to focus on the connection between clu and mitochondrial function in fruit fly muscle cells. The researchers recently published their work in the journal Human Molecular Genetics.

“We are trying to understand how muscles develop and how healthy muscles are maintained throughout the entire life of a fruit fly in the hopes of applying this knowledge to the human body,” Geisbrecht said.

Geisbrecht uses fruit fly muscles as a model for human muscles because of their similar structures — approximately 85 percent of the human disease genes have corresponding genes in the fruit fly. Fruit flies also have a short lifecycle of 10 days from when the egg is laid to when adults emerge, which allows for the rapid observation of muscle development and maintenance.

The connection between fruit fly and human muscles has made it possible to understand the role of the clu gene that — when mutated — causes defects in the localization and turnover of damaged mitochondria. A buildup of damaged mitochondria ultimately affects the ability of muscles and nerves to function properly. Geisbrecht and her team are just beginning to understand how clu interacts with a gene called parkin that — when mutated in humans — results in Parkinson’s disease.

People who are born with mutations in the parkin gene do not develop Parkinson’s disease until later in adult life. The same is true for fruit flies with defects in clu or parkin: These fruit flies proceed through the larval and pupal stage of insect development and emerge as adults, but quickly die because their muscles and neurons degenerate.

“If you think about a tissue in the body that uses more energy than anything else, of course it’s your muscle tissue,” Geisbrecht said. “Proper mitochondrial function is essential to having healthy, developed muscles. It’s an important connection.”

Geisbrecht’s team plans to continue studying fruit flies to better understand the connection between human disease genes and muscle function. Their work could lead to better treatment for Parkinson’s disease or other muscle diseases.

Aside from muscle or neurodegenerative diseases, maintaining healthy muscle tissue also is important in the general population, where common diseases can also lead to muscle problems. For example, muscle wasting, or muscle deterioration, can be a huge problem for people with diabetes or cancer.

“Muscle wasting for people with end-stage diabetes or cancer is often a bigger problem than the cancer or diabetes itself because it causes people to become immobile and lose the ability to make their muscles function well again,” Geisbrecht said. “We want to understand what happens at the cellular level — what these genes or proteins are doing.”

New Techniques to Assess the Fate of Stem Cells in vivo

Publication in Genes & Development: researchers at the Université libre de Bruxelles, ULB develop new techniques to assess the fate of stem cells in vivo.

Stem cells ensure the development of tissues, their daily maintenance and their repair following injuries. One of the key questions in the field of stem cell biology is to define the different cell lineages in which stem cells can differentiate into. Stem cells can be multipotent, meaning they present the ability to give rise to more than one lineage, or unipotent, meaning they can only differentiate into one cell lineage. Lineage tracing experiments are routinely used in the fields of developmental and stem cell biology to assess the fate of stem cells in vivo. However, no rigorous method has yet been established to interpret with great precision and statistical confidence the issue of multipotency versus unipotency in lineage tracing experiments.

In a study that makes the cover of the current issue of Genes & Development, researchers from the ULB Cancer Research Center, U-CRC, led by Cédric Blanpain, MD/PhD, WELBIO investigator and Professor at the Faculty of Medicine, Université libre de Bruxelles, Belgium, developed new methods to assess with great precision the multipotent or unipotent fate of mammary gland and prostate stem cells.

Aline Wuidart and colleagues developed two novel methods to determine whether stem cells in the mammary gland and in the prostate are multipotent or unipotent during development and adult maintenance. In collaboration with physicists of the University of Cambridge, they developed a novel bio-statistical framework to define multipotency with high confidence in multicolor lineage tracing experiments. They developed another method called lineage tracing at saturation to assess the fate of all stem cells in a given tissue and the flux of cells between different lineages. “It was really important to sort out the issue of multipotency of mammary and prostate stem cells in a definitive manner. These novel and powerful tools combining multicolor lineage tracing, bio-statistical analysis and lineage tracing at saturation will allow to interpret the lineage experiments with much greater confidence”, comments Aline Wuidart, the first author of this study.

These new findings unambiguously demonstrate that, while the prostate develops from multipotent stem cells, only unipotent stem cells mediate mammary gland development and adult tissue remodeling. “These methods offer a rigorous framework to assess the lineage relationship and stem cell fate in different organs and tissues. These techniques will become the new standard to decipher the lineage relationship in many other organs or tissues during development, tissue repair and tumor initiation.” comments Cédric Blanpain, the senior author of the Genes & Development paper.

When it comes to developing stem cell treatments, seeing is half the battle

Stem cell therapies hold great promise in treating a variety of diseases, but in order to develop them researchers must first be able to monitor them inside the body. Enter the contrast agent.

“Often things go wrong right away when stem or therapeutic cells are injected into the body because some cells can migrate, while other dying cells are eaten by the body and expelled,” says Xiao-an Zhang, an assistant professor of chemistry at U of T Scarborough.

“It’s important to know if these cells are being injected in the right place, where they go once inside the body and whether they’re still alive. The only way to do that is with an effective contrast agent.”

Conventional contrast agents are directly injected into the body to make some tissues or diseases more clearly visible on MRI scans. The one developed by Zhang and his team, including Ph.D. student Inga Haedicke, U of T Assistant Professor Hai-Ling Margaret Cheng and two research groups (Dr. Timothy Scholl and Dr. Paula Foster) from Western University, can improve monitoring at the cellular level, which is a crucial element in measuring the effectiveness of stem and therapeutic cell treatments.

While still early in development, stem and therapeutic cells may one day offer effective treatments against diseases, particularly cancer. But one major hurdle in developing these treatments is an inability to effectively monitor them once inside the body.

“Current MRI methods are not great at looking at what’s going on at the cell or sub-cellular level. It’s just not powerful enough – the resolution and sensitivity needs to be higher and the contrast needs to be greater in order to distinguish one type of cell from another,” says Zhang.

“Traditional MRI can’t do quite what we need it to do right now, but there’s huge opportunity to improve the technology.”

Magnetic resonance imaging (MRI) uses a magnetic field and radio waves to produce a detailed image of tissues within the body. MRI is ideal for medical imaging because it’s milder than techniques like CT scans or X-rays since it’s not as invasive and does not rely on ionizing radiation.

There are quite a few technical challenges when developing an effective contrasting agent for cellular imaging. For one, it needs to be non-toxic or low in toxicity so it doesn’t damage cells. It also needs to be able to enter cells and accumulate in order to provide a clear enough contrast from the rest of objects in the image, notes Zhang.

The agent developed by Zhang and his team addresses these challenges by using manganese porphyrin. Manganese is a micronutrient that the body’s cells can handle and forms a very stable complex with the porphyrin, a type of pigment molecule that can help to achieve the necessary properties. Using a new porphyrin developed by Haedicke, the agent can be delivered to cells more efficiently in smaller concentrations and can accumulate more effectively than current alternatives.

“The real positive aspect of this design is that it’s cell permeable, and that the new mechanism allows it to stay inside the cell and accumulate,” says Haedicke. “This is extremely important for labelling which cells are being monitored.”

The research, which will be published in the journal Chemical Science, received funding from the Canada Foundation for Innovation (CFI) and the Natural Sciences and Engineering Research Council of Canada (NSERC).

The next steps for Zhang and his team is to focus mostly on using the agent on different types of stem cells and to test them in vivo.

Fighting hospital germs with sugar

A vaccine against one of the most dangerous hospital germs may soon be available. Scientists from the Max Planck Institute of Colloids and Interfaces in Potsdam and the Freie Universität Berlin have developed a substance that elicits an immune response against the gut bacterium Clostridium difficile. The potential vaccine resembles the sugar structures presented on the surface of the bacterium and therefore primes the immune system to recognize the pathogen itself. C. difficile infects a large proportion of patients in hospitals and kills around 15,000 people a year in the USA alone. Doctors could treat the infection with antibiotics, but the bacterium mutates constantly, allowing it to escape the effects of the drugs. The discovery by the Max Planck researchers may pave the way for developing inexpensive and effective vaccines and drugs against C. difficile.

Around 40 percent of patients in hospitals and nursing homes carry the gut bacterium C. difficile. Such patients are easy prey for the pathogen. Because the patients’ intestinal flora is often damaged by antibiotic treatments, the bacteria are able to spread unhindered. Moreover, treatment of the infection becomes increasingly difficult, as the bacteria tend to develop resistance to antibiotics.

Researchers at the Max Planck Institute of Colloids and Interfaces have now constructed a molecule that could protect patients against C. difficile. It resembles the characteristic sugar coating on the surface of bacteria and, as such, is able to elicit a similar immune response as the bacterium itself. The molecule could thus be used as a vaccine, because once the immune system has produced antibodies against a pathogen, it is prepared to fend off the invaders in the event of a later infection.

Synthetic molecule as a cost-effective alternative for immunization

The researchers first investigated which parts of the sugar coating are actually necessary to trigger an immune response. They then constructed an artificial molecule with those properties by attaching the essential sugar structures to an amino acid backbone. Coupled with an immunostimulating peptide, the molecule stimulated the immune system in mice to produce antibodies that were effective against the similarly constructed surface sugars of C. difficile. The mice are therefore protected against a subsequent infection with the bacterium. Moreover, it may be possible to use the molecule to produce therapeutic antibodies that can be administered to sick patients to boost their immune system and combat infections.

Many bacteria bear characteristic carbohydrates on their surface, and it is known that these surface sugars are suitable for immunization purposes. However, the surface sugars usually have to be detached from specially bred microbes – an expensive and complicated process. By synthesizing artificial molecules for immunization, the researchers have now come up with a cost-effective alternative. “Our findings are a very good example of how basic research into the human immune response to sugars can lead to new candidates in the fight against dangerous hospital germs,” says Peter H. Seeberger, Director at the Max Planck Institute of Colloids and Interfaces and Professor at Freie Universität Berlin. As early as 2011, he and his team synthesized a molecule for immunizing against C. difficile; at the time, however, they used a different surface sugar molecule as a template.

In order to progress from research results to actual use in patients, the scientists at the Max Planck Institute of Colloids and Interfaces in Potsdam are working with Vaxxilon AG (Reinach, Switzerland) to develop novel carbohydrate-based vaccines. Vaxxilon has licensed a portfolio of vaccine candidates against a number of pathogens, including C. difficile.

Breast cancer drug found to reduce seizures

A class of drug that inhibits estrogen production and is used to treat breast cancer has been found to quickly and effectively suppress dangerous brain seizures, according to a new Northwestern University study.

“The effect was profound and very clear,” said Catherine S. Woolley, senior author of the study, which was conducted in a rat model of status epilepticus, a condition characterized by a prolonged episode of seizure activity. “This shows that clinically available drugs could be effective therapies for suppressing seizures in humans.”

Woolley and postdoctoral fellow Satoru M. Sato also discovered, to their surprise, that seizures stimulate the production of estrogens in the brain of both males and females and that this plays a previously unknown role in the escalation of seizure activity. Estrogen synthesis during a seizure fuels the seizure, making it worse.

The findings suggest a new approach to treating seizures in humans: shut down the brain’s production of estrogen when a seizure first begins. Current seizure treatments are not targeted; they work by dampening neural activity generally and come with many side effects, such as drowsiness, dizziness or difficulty concentrating.

“Status epilepticus is a neurological emergency,” Woolley said. “This occurs when large groups of connected neurons fire excessively and in synchrony for a prolonged time. Recognizing that estrogen synthesis during seizures fuels seizure activity gives researchers a specific target for therapeutically breaking the dangerous escalation cycle.”

Woolley is the William Deering Chair in Biological Sciences, professor of neurobiology in the Weinberg College of Arts and Sciences and a member of the Women’s Health Research Institute at Northwestern University Feinberg School of Medicine.

The study, published this week as a Research Article by the online life sciences and biomedicine journal eLife, builds on past work showing estrogen increases neuronal activity via a number of mechanisms.

In their study, Woolley and Sato found inhibiting estrogen synthesis just after seizure onset strongly suppressed seizures in both sexes, without anti-seizure drugs or other interventions. The effect was seen both in the animal’s behavior and in hippocampal electroencephalogram (EEG) recordings.

The scientists injected male and female animals with either an inert substance or an aromatase inhibitor, either letrozole or fadrozole, just after the start of a chemically induced seizure. (An aromatase inhibitor inhibits estrogen synthesis; letrozole, or Femera®, is used clinically to treat breast cancer in postmenopausal women.) They studied the animals for up to six hours and found both fadrozole and letrozole strongly suppressed seizures in both sexes.

The hippocampus is a critically important part of the brain in the initiation and propagation of seizure activity. In another part of their study, Woolley and Sato found the impact of seizures on estrogen production in the hippocampus was surprisingly large in both sexes, showing a two- to three-fold increase during seizures.

Woolley said it is important to distinguish between seizures and epilepsy, which are not synonymous. Epilepsy, which affects about 1 percent of the population, is a condition in which a person has spontaneous recurrent seizures, often lasting only a few minutes. Status epilepticus is a more severe seizure episode, affecting about 40 people per 100,000 per year.

The overall mortality rate of status epilepticus is estimated at 20 percent, and patients who recover have an increased likelihood of subsequent unprovoked seizures, the researchers say. New approaches to acute seizure control are needed.

“Given the unacceptably high mortality rate of status epilepticus in humans, these data from the Northwestern study are likely to elicit great interest by physicians in the field,” said Dr. Stephen M. Smith, director of medical critical care at the VA Portland Health Care System. He was not involved in the study but is familiar with Woolley’s research.

“Hopefully, this new study will trigger clinical trials to determine the efficacy and safety of currently available aromatase inhibitors in patients with status epilepticus,” said Smith, professor of medicine at Oregon Health & Science University.