Using mice, lab-grown cells and clues from a related disorder, Johns Hopkins researchers have greatly increased understanding of the causes of systemic sclerosis, showing that a critical culprit is a defect in the way certain cells communicate with their structural scaffolding. They say the new insights point the way toward potentially developing drugs for the disease, which affects approximately 100,000 people in the United States.
‘Until now we’ve had little insight and no effective treatment strategies for systemic sclerosis, and many patients die within a year of diagnosis,’ says Hal Dietz, M.D., the Victor A. McKusick Professor of Genetics and Medicine in the Institute of Genetic Medicine, director of the Smilow Center for Marfan Syndrome Research at Johns Hopkins and Howard Hughes Medical Investigator. ‘Our group created mouse models that allowed us to learn about the sequence of events that leads to the disease’s symptoms, and we hope drugs can be developed that target one or more of these events.’
Patients with systemic sclerosis, also known as systemic scleroderma, experience a sudden hardening, or fibrosis, of the skin. For some patients, this hardening occurs only in limited areas, but for others, it quickly spreads across the body and to organs such as the heart, intestines and kidneys. It is this fibrosis of the internal organs that is often fatal.
Systemic sclerosis rarely runs in families, Dietz says, making the gene for the disease, if it exists, very difficult to find. Without a known genetic mutation, researchers had not been able to create a genetically altered mouse with which to study the condition. But Dietz’s group was struck by the similarities between systemic sclerosis and a less severe, much rarer condition called stiff skin syndrome (SSS), which does run in families, and they suspected that learning more about SSS would also shed light on systemic sclerosis.
In a previous experiment, they pinpointed the genetic mutation responsible for SSS in a gene for a protein called fibrillin-1, which plays a role in other connective tissue disorders. In certain types of tissues, including skin, fibrillin-1 helps make up the scaffolding for cells. The specific changes in fibrillin-1 seen in SSS patients were predicted to impair the ability of cells to make contact with fibrillin-1 through bridging molecules called integrins.
In the current study, M.D./Ph.D. student Elizabeth Gerber created a line of mice with a genetic variant similar to that found in SSS patients. To test the group’s hypothesis, Gerber also created a line of mice with a variant the team knew would prevent fibrillin-1 from interacting with integrin. As the team expected, both groups of mice developed patches of stiff skin, along with elevated levels of proteins and cells involved in the immune response—much like humans with SSS or systemic sclerosis. ‘It seemed we were right that the SSS mutation causes the condition by blocking fibrillin’s interaction with integrin,’ Dietz says. ‘Something else we found was that both types of mice had high levels of integrin in their skin, which made us think their cells were trying to compensate for the lack of fibrillin-integrin interaction by making more and more integrin.’
This still left open the question of what was ultimately causing fibrosis, however: Was it the integrin levels or the immune response? Dietz’s group delved deeper into the question by creating mice that had both the SSS mutation and artificially low levels of integrin, and found that the mice never developed fibrosis or an abnormal immune response. ‘They looked normal,’ Dietz says.
The team next tried waiting until mice with the SSS mutation had developed fibrosis, then treating them with a compound known to block a key molecule with known connections to both fibrosis and the immune response. This reversed the mice’s skin fibrosis and immunologic abnormalities. The team also tested the compounds on lab-grown human skin cells with systemic sclerosis, with the same results. This raises the possibility that systemic sclerosis patients could eventually be treated with similar compounds in humans, Dietz says. A number of the compounds that proved effective in SSS mice and systemic sclerosis cells are currently being explored by drug companies for the treatment of other conditions, prominently including cancer.
The results raised another big question for the team: Which of the several types of skin cells were responsible for the runaway immune response and fibrosis? They traced the activity to so-called plasmacytoid dendritic cells, or pDCs, a cell type known to either tamp down or ramp up immune response, depending on the circumstances.
‘Dietz’s work gives scleroderma patients hope that we have gained fundamental insights into the process of fibrosis in scleroderma. In particular, I am confident that within a relatively short time, novel therapies can be tested in patients, and I am optimistic that such treatments will have a profound effect,’ says Luke Evnin, Ph.D., chairman of the board of directors of the Scleroderma Research Foundation and a scleroderma patient. John Hopkins Medicine

Genes could give new direction for diagnostics and therapeutics research, says a TAU researcher

Amyotrophic Lateral Sclerosis (ALS) is a devastating motor neuron disease that rapidly atrophies the muscles, leading to complete paralysis. Despite its high profile — established when it afflicted the New York Yankees’ Lou Gehrig — ALS remains a disease that scientists are unable to predict, prevent, or cure.

Although several genetic ALS mutations have been identified, they only apply to a small number of cases. The ongoing challenge is to identify the mechanisms behind the non-genetic form of the disease and draw useful comparisons with the genetic forms.

Now, using samples of stem cells derived from the bone marrow of non-genetic ALS patients, Prof. Miguel Weil of Tel Aviv University’s Laboratory for Neurodegenerative Diseases and Personalized Medicine in the Department of Cell Research and Immunology and his team of researchers have uncovered four different biomarkers that characterise the non-genetic form of the disease. Each sample shows similar biological abnormalities to four specific genes, and further research could reveal additional commonalities. ‘Because these genes and their functions are already known, they give us a specific direction for research into non-genetic ALS diagnostics and therapeutics,’ Prof. Weil says.
To hunt for these biomarkers, Prof. Weil and his colleagues turned to samples of bone marrow collected from ALS patients. Though more difficult to collect than blood, bone marrow’s stem cells are easy to isolate and grow in a consistent manner. In the lab, he used these cells as cellular models for the disease. He ultimately discovered that cells from different ALS patients shared the same abnormal characteristics of four different genes that may act as biomarkers of the disease. And because the characteristics appear in tissues that are related to ALS — including in muscle, brain, and spinal cord tissues in mouse models of genetic ALS — they may well be connected to the degenerative process of the disease in humans, he believes.

Searching for the biological significance of these abnormalities, Prof. Weil put the cells under stress, applying toxins to induce the cells’ defence mechanisms. Healthy cells will try to fight off threats and often prove quite resilient, but ALS cells were found to be overwhelmingly sensitive to stress, with the vast majority choosing to die rather than fight. Because this is such an ingrained response, it can be used as a feature for drug screening for the disease, he adds.
Whether these biomarkers are a cause or consequence of ALS is still unknown. However, this finding remains an important step towards uncovering the mechanisms of the disease. Because these genes have already been identified, it gives scientists a clear direction for future research. In addition, these biomarkers could lead to earlier and more accurate diagnostics. American Friends of Tel Aviv University

Coeliac disease (gluten intolerance) sufferers who have residual inflammation of the intestinal mucosa several years after diagnosis have a higher risk of contracting cancer of the lymphatic system _ lymphoma _ than those patients whose intestinal mucosa have healed. These are the findings of a new study led by researchers from Karolinska Institutet.
When a patient is diagnosed with gluten intolerance, biopsies of the small intestine show that the long finger-like projections that absorb nutrients and moisture from the food we eat – the intestinal villi – have flattened out. Damaged villi can lead to diarrhoea, weight loss and iron deficiency, which are common symptoms of gluten intolerance. Once the patient has been diagnosed and starts to eat a gluten-free diet, the damage to the intestinal mucosa is expected to heal so that the villi recover. However, in some cases the intestine does not heal. Poor healing is observed if the patient fails to follow a gluten-free diet, but also occurs in some patients who do follow such a diet.
It was already known that gluten-intolerant individuals are at a greater risk of contracting lymphoma, but until now it has not been known whether this risk is affected if the intestine heals. One reason for being unable to make this connection is that insufficient data has been available. Over the course of the last ten years, however, Karolinska Institutet_s Professor of Clinical Epidemiology Jonas F Ludvigsson and his colleagues have compiled a database containing the results of intestinal biopsies from around 29,000 patients at all Swedish pathology departments.
‘This study shows that a control biopsy can be used after the patient has started a gluten-free diet to show whether the patient has a high or low risk of lymphoma in the future,’ explains Professor Ludvigsson. ‘The new blood tests (_antibodies_) that are now available, and that are used increasingly often in the diagnosis of coeliac disease, can help healthcare professionals to diagnose the disease and to monitor patients, but are no replacement for a small intestine biopsy.’
The study involved researchers identifying gluten-intolerant patients who underwent an intestinal biopsy between six months and five years after their diagnosis. These patients were then monitored for an average of eight to nine years after taking the biopsy. Of a total of 7,625 gluten-intolerant patients, the intestine had healed in 4,317 patients (57 percent) by the time of the biopsy, while the remaining 3,308 patients (43 percent) still had damaged villi when the biopsy was taken.
The study also showed that, on average, gluten-intolerant individuals are 2.81 times more likely than others to suffer from lymphoma. However, those patients whose intestines did not heal were 3.78 times more likely to contract lymphoma, whereas those whose intestines did heal were 1.5 times more likely. According to the researchers, it is therefore important that the intestine heals in order to reduce the risk of these patients developing lymphoma. Karolinska Institute

Researchers at Boston University School of Medicine (BUSM) have discovered a molecule that could help lead to the non-invasive detection of lung cancer as well as its treatment. Using RNA sequencing, the team looked at airway epithelial cells and identified a regulatory molecule that was less abundant in people with lung cancer and inhibits lung cancer cell growth. The findings suggest that this molecule may aid in diagnosing lung cancer in earlier stages and could potentially, when at healthy levels, aid in treating the disease.
According to the National Cancer Institute (NCI), lung cancer is the leading cause of cancer death among both men and women in the United States, and 90 percent of lung cancer deaths among men and approximately 80 percent of lung cancer deaths among women are due to smoking. The NCI also estimates that approximately 373,489 Americans are living with lung cancer and its treatment costs approximately $10.3 billion in the United States each year.
MicroRNA’s are a new class of molecules classified as important regulators of the activity of other genes. In this study, the research team used a next-generation RNA sequencing technology and identified that a microRNA named miR-4423 in epithelial airway cells plays a major role in how these cells develop. In epithelial cells from the airway of smokers with lung cancer, levels of miR-4423 were decreased.
‘These results suggest measuring the levels of microRNAs like miR-4423 in cells that line the airway could aid in lung cancer detection through a relatively non-invasive procedure,’ said Avrum Spira, MD, MSc, the Alexander Graham Bell professor of medicine and chief of the division of computational biomedicine at BUSM, one of the study’s senior authors.
Using experimental models in vitro and in vivo, the research team demonstrated that miR-4423 can both promote the development of the normal airway cells and suppress lung cancer cell growth. This suggests that miR-4423 plays a major regulatory role in cell fate decisions made by airway epithelial cells during maturation and low levels of miR-4423 contributes to lung cancer development. Interestingly, throughout the body, miR-4423 seems only to be present in high levels in the airway epithelium, suggesting this could be a very specific process occurring only in the lungs.
‘Our findings open up the option to study whether returning miR-4423 levels to normal in the airway could help stop cancer growth and potentially be a way to treat lung cancer,’ said Catalina Perdomo, PhD, a researcher in the division of computational biomedicine at BUSM who is the paper’s lead author.
‘Interestingly, when we examined the genomes of other species for microRNAs that might function like miR-4423, we did not find anything in non-primates,’ said Marc Lenburg, PhD, an associate professor in computational medicine and bioinformatics at BUSM who is one the study’s senior authors. ‘It makes us wonder what it is different about lung development in primates and excited that this could be a very specific process to target for lung cancer treatment.’ EurekAlert

It turns out the love hormone oxytocin is two-faced. Oxytocin has long been known as the warm, fuzzy hormone that promotes feelings of love, social bonding and well-being. It’s even being tested as an anti-anxiety drug. But new Northwestern Medicine research shows oxytocin also can cause emotional pain, an entirely new, darker identity for the hormone.

Oxytocin appears to be the reason stressful social situations, perhaps being bullied at school or tormented by a boss, reverberate long past the event and can trigger fear and anxiety in the future.

That’s because the hormone actually strengthens social memory in one specific region of the brain, Northwestern scientists discovered.

If a social experience is negative or stressful, the hormone activates a part of the brain that intensifies the memory. Oxytocin also increases the susceptibility to feeling fearful and anxious during stressful events going forward.

(Presumably, oxytocin also intensifies positive social memories and, thereby, increases feelings of well being, but that research is ongoing.)

The findings are important because chronic social stress is one of the leading causes of anxiety and depression, while positive social interactions enhance emotional health. The research, which was done in mice, is particularly relevant because oxytocin currently is being tested as an anti-anxiety drug in several clinical trials.

‘By understanding the oxytocin system’s dual role in triggering or reducing anxiety, depending on the social context, we can optimise oxytocin treatments that improve well-being instead of triggering negative reactions,’ said Jelena Radulovic, the senior author of the study and the Dunbar Professsor of Bipolar Disease at Northwestern University Feinberg School of Medicine.

This is the first study to link oxytocin to social stress and its ability to increase anxiety and fear in response to future stress. Northwestern scientists also discovered the brain region responsible for these effects — the lateral septum – and the pathway or route oxytocin uses in this area to amplify fear and anxiety.

The scientists discovered that oxytocin strengthens negative social memory and future anxiety by triggering an important signalling molecule — ERK (extracellular signal regulated kinases) — that becomes activated for six hours after a negative social experience. ERK causes enhanced fear, Radulovic believes, by stimulating the brain’s fear pathways, many of which pass through the lateral septum. The region is involved in emotional and stress responses. Northwestern University