Muscular dystrophy treatment with Tamoxifen and Raloxifene

Researchers study the use of selective estrogen receptor modulators tamoxifen and raloxifene in patients with muscular dystrophies (MD). Results in an animal study showed significant improvement muscular function. The study findings are published in journal American Journal of Pathology.

Animal study results showing improvement in grip strength, running and changes in muscle histology following use of tamoxifen, and raloxifene. Credit: The American Journal of Pathology.

Selective estrogen receptor modulators have been used for their anti-inflammatory, antifibrosis, prevention of bone loss, and muscle building effects. The investigators found several indicators that tamoxifen and raloxifene delay or even halt disease progression. Within one month,  mice treated with either tamoxifen or raloxifene reduced muscle pathology with a significant reduction in the numbers of degenerating fibers. In one year treated mice show significantly lower histological changes compared to control group which showed high variation in muscle fiber size with focal inflammatory infiltrations.

These histological changes were accompanied by functional improvements in grip force production, extended running time and distance in a treadmill test, and enhancement in cardiac and respiratory functions.

“Our results show that there are two important advantages of tamoxifen and raloxifene treatment over steroids, which have limited benefits for patients with muscular dystrophies. First, the selective estrogen receptor modulators improve both histology and function of all muscles; although steroids improve histology, they improve function to a much lesser extent. Second, selective estrogen receptor modulators enhance bone density, whereas steroids exacerbate osteoporosis and increase the risk for fractures,” explained Qi Long Lu, MD, PhD, director of the McColl-Lockwood Laboratory for Muscular Dystrophy Research, Neuromuscular/ALS Center, Department of Neurology, Atrium Health’s (formerly Carolinas HealthCare System’s) Carolinas Medical Center, Charlotte (NC).

“selective estrogen receptor modulators therapy has great potential to significantly delay or halt muscular dystrophies progression. With the vast amount of safety data available, the selective use of tamoxifen and raloxifene in male and female patients with muscular dystrophies is an attractive and realistic alternative to steroids,” noted Dr. Lu.

Reference: Wu, Bo, Sapana N. Shah, Peijuan Lu, Lauren E. Bollinger, Anthony Blaeser, Susan Sparks, Amy D. Harper, and Qi L. Lu. “Long-Term Treatment of Tamoxifen and Raloxifene Alleviates Dystrophic Phenotype and Enhances Muscle Functions of FKRP Dystroglycanopathy.” The American Journal of Pathology 188, no. 4 (2018): 1069-080. doi:10.1016/j.ajpath.2017.12.011.

Research funding: Carolinas Muscular Dystrophy Research Endowment at the Carolinas HealthCare Foundation.

Adapted from press release by Elsevier.

Fatty liver could be caused by E-cigarette smoke.

Researchers found that regular e-cigarette exposure may lead to an accumulation of fat in the liver. Their conclusion was based on an animal study on mice. These research findings are presented at ENDO 2018, the Endocrine Society’s 100th annual meeting in Chicago, Illinois.

This study was led by Theodore C. Friedman, M.D., Ph.D., Chairman of the Department of Internal Medicine and Endowed Professor of Cardio-Metabolic Medicine at Charles R. Drew University of Medicine & Science in Los Angeles, California.

In this research study, researchers studied mice without apolipoprotein E gene as these are more prone to developing heart disease and non-alcoholic fatty liver disease. Study randomized these mice into two groups one was exposed to saline aerosol and other to e-cigarette smoke. Both were fed the same diet. Researchers analyzed liver samples from both mice. They then examined gene expression by using RNA sequence analysis and found that mice which were exposed to e-cigarette smoke had changes in 433 genes associated with fatty liver and circadian rhythm dysfunction.

It is noted that non-alcoholic fatty liver disease and liver is associated with nicotine use and circadian rhythm dysfunction.

Adapted from press release by the Endocrine Society.

Researchers find possible link between autism and nuclear receptor protein LXRβ

Research by University of Houston scientists discovered a possible link between nuclear receptor protein LXRβ (Liver X receptor Beta) and autism spectrum disorder. They found that nuclear receptor LXRβ deletion causes poor development of dentate gyrus, a part of brain’s hippocampus. The dentate gyrus, or DG, is responsible for emotion and memory and is known to be involved in autism spectrum disorders (ASD).

This study is led by Margaret Warner and Jan-Åke Gustafsson. The results are published in journal Proceedings of the National Academy of Sciences.”Our findings suggest early changes in dentate gyrus neurogenesis ultimately provide an aberrant template upon which to build the circuitry that is involved in normal social function,” said Warner.

Researchers conducted an animal study using LXRβ-deficient mice. Behavior analysis of these mice showed autistic-like behaviors, including social interaction deficits and repetitive behavior.”Knocking out LXRβ led to autistic behavior and reduced cognitive flexibility,” said Warner. “In this paper, we share our findings that that deletion of the LXRβ (Liver X receptor Beta) causes hypoplasia or underdevelopment in the dentate gyrus and autistic-like behaviors, including abnormal social interaction and repetitive behavior.”

Citation: Cai, Yulong, Xiaotong Tang, Xi Chen, Xin Li, Ying Wang, Xiaohang Bao, Lian Wang, Dayu Sun, Jinghui Zhao, Yan Xing, Margaret Warner, Haiwei Xu, Jan-Åke Gustafsson, and Xiaotang Fan. “Liver X receptor β regulates the development of the dentate gyrus and autistic-like behavior in the mouse.” Proceedings of the National Academy of Sciences, 2018, 201800184. doi:10.1073/pnas.1800184115.

Adapted from press release by the University of Houston.

Understanding molecular mechanisms behind germinal matrix hemorrhage

Researchers have utilized a mouse model to determine the molecular mechanisms underlying germinal matrix hemorrhage. Nearly 12,000 premature infants born annually in the US are affected by neonatal brain hemorrhage which results in mortality and long-term morbidity. Unfortunately, no treatment exists for this condition, and the only preventive measure is steroids before birth, which has deleterious effects on brain development. The hemorrhage originates from the rupture of small brain vessels in a highly fragile region known as the germinal matrix.

However, the cellular and molecular mechanisms of this disorder remain poorly understood. In a recent study led by Drs. Jui Dave and Daniel Greif at Yale University found that mutant embryonic mice lacking the gene, Alk5 in pericytes (cells that support small brain vessels) develop germinal matrix hemorrhage. The condition arises due to enhanced proliferation of endothelial cells and upregulated protease activity which result in vessel rupture and hemorrhage. Furthermore, the study reveals that treating mutant mice with a recombinant protein, TIMP3 effectively attenuates the hemorrhage and reduces bleeding. The study is published in the journal Developmental Cell.

The findings from this study provide novel insights into the pathogenesis of germinal matrix hemorrhage and are likely to shed light on other brain disorders such as stroke and aneurysms as well. Although further research is needed to fully understand the beneficial effects of TIMP3, this study promises to broaden the scope of therapeutic intervention for this devastating disorder.

Citation: Dave, Jui M., Teodelinda Mirabella, Scott D. Weatherbee, and Daniel M. Greif. “Pericyte ALK5/TIMP3 Axis Contributes to Endothelial Morphogenesis in the Developing Brain.” Developmental Cell, 2018. doi:10.1016/j.devcel.2018.01.018.

New target receptor for treating depression GPR158

Researchers from the Scripps Research Institute find a new target receptor called GPR158 for treating depression. Their research shows that individuals with high levels of above receptor may be more susceptible to depression following chronic stress.

“The next step in this process is to come up with a drug that can target this receptor,” says Kirill Martemyanov, Ph.D., co-chair of the TSRI Department of Neuroscience and senior author of the new study, which is published in the journal eLife.

“We need to know what is happening in the brain so that we can develop more efficient therapies,” says Cesare Orlandi, Ph.D., the senior research associate at TSRI and co-first author of the study.

The researchers found elevated GPR158 protein in depressed patients, suspected it could play a major role in the disease process. They then conducted an animal study using male and female mice with and without above receptor. Subsequent behavioral tests showed that mice with elevated levels of GPR158 showed signs of depression following chronic stress and suppressing GPR158 protected them from developing depressive behavior and also resilient to stress.

Next, the researchers examined why GPR158 has these effects on depression. The team demonstrated that GPR158 affects key signaling pathways involved in mood regulation in the region of the brain called prefrontal cortex, though the researchers emphasized that the exact mechanisms remain to be established.

Martemyanov explains that GPR158 is a so-called “orphan receptor” (which gets its name because its binding partner/partners are unknown) with a poorly understood biology and mechanism of action. GPR158 appears to work downstream from other important brain systems, such as the GABA, a major player in the brain’s inhibitory control and adrenergic system involved in stress effects.

Laurie Sutton, Ph.D., a research associate at TSRI and co-first author of the study, says this finding matches what doctors have noticed in people who have experienced chronic stress. “There’s always a small population that is resilient they don’t show the depressive phenotype,” says Sutton.

As the search goes on for additional targets for depression, Martemyanov says scientists are increasingly using new tools in genome analysis to identify orphan receptors like GPR158. “Those are the untapped biology of our genomes, with significant potential for development of innovative therapeutics,” he says.

Citation: Sutton, Laurie P., Cesare Orlandi, Chenghui Song, Won Chan Oh, Brian S. Muntean, Keqiang Xie, Alice Filippini, Xiangyang Xie, Rachel Satterfield, Jazmine D W Yaeger, Kenneth J. Renner, Samuel M. Young, Baoji Xu, Hyungbae Kwon, and Kirill A. Martemyanov. “Orphan receptor GPR158 controls stress-induced depression.” ELife 7 (2018). doi:10.7554/elife.33273.

Research funding: National Institutes of Health, University of Iowa, Max Planck Society, Canadian Institutes of Health Research Fellowship.

Adapted from press release by the Scripps Research Institute.

Effects of flu on brain

Group of researchers from Germany and USA studied effects of influenza virus on brain cells. The study published in the Journal of Neuroscience finds that female mice infected with two different strains of the flu shows changes in structure and function of the hippocampus. These changes persist for one month after infection.

The long-term effect of influenza A virus infection on glial cell density and activation status within the hippocampal subregions. The neurotropic H7N7 IAV infection induced an increased microglia density in all hippocampal subregions at 30 days post-infection. Credit: Hosseini et al., JNeurosci

Influenza could present with neurological symptoms in some cases. So far research has not studied the long-term effect of the virus in the brain.

Researchers investigated three different influenza strains (H1N1, H3N2, H7N7). Two of these strains, H3N2 and H7N7, caused memory impairments that were associated with structural changes such as dendritic spine loss to neurons in the hippocampus. These changes persist up to 30 days following infection and fully recovered in 120 days.

Researchers feel that in the acute phase of influenza infection, this neuroinflammation in hippocampus alters the neuronal morphology and can cause cognitive deficits. The results also provide evidence that neuroinflammation induced by influenza virus infection can lead to longer-lasting alterations in neuronal connectivity with associated impairments in spatial memory formation.

Citation: Hosseini, Shirin, Esther Wilk, Kristin Michaelsen-Preusse, Ingo Gerhauser, Wolfgang Baumgärtner, Robert Geffers, Klaus Schughart, and Martin Korte. “Long-term neuroinflammation induced by influenza A virus infection and the impact on hippocampal neuron morphology and function.” The Journal of Neuroscience, 2018, 1740-17. doi:10.1523/jneurosci.1740-17.2018.

Research funding: Ministry of Science and Culture of Lower Saxony, Helmholtz-Association.

Adapted from press release by the Society for Neuroscience.

Stem cell treatment shows promise for stroke recovery in animal study

A team of researchers  have developed a new treatment for stroke that reduces brain damage and accelerates the brain’s natural healing tendencies in animal models. The findings are published in the journal Translational Stroke Research.

Exosomes, shown as small red punctate clusters, are taken up by neurons, shown as green cell extensions surrounding a blue nucleus. Credit: University of Georgia

The research team led by UGA professor Steven Stice and Nasrul Hoda of Augusta University created a treatment called AB126 using extracellular vesicles (EV), fluid-filled structures known as exosomes, which are generated from human neural stem cells. Fully able to cloak itself within the bloodstream, this type of regenerative extracellular vesicles therapy appears to be the most promising in overcoming the limitations of many cell therapies-with the ability for exosomes to carry and deliver multiple doses-as well as the ability to store and administer treatment. Small in size, the tiny tubular shape of an exosome allows extracellular vesicles therapy to cross barriers that cells cannot.

“This is truly exciting evidence, because exosomes provide a stealth-like characteristic, invisible even to the body’s own defenses,” said Stice, Georgia Research Alliance Eminent Scholar and D.W. Brooks Distinguished Professor in the College of Agricultural and Environmental Sciences. “When packaged with therapeutics, these treatments can actually change cell progression and improve functional recovery.”

Following the administration of AB126, the researchers used MRI scans to measure brain atrophy rates in preclinical, age-matched stroke models, which showed an approximately 35 percent decrease in the size of injury and 50 percent reduction in brain tissue loss – something not observed acutely in previous studies of exosome treatment for stroke. Outside of rodents, the results were replicated by Franklin West, associate professor of animal and dairy science, and fellow RBC members using a porcine model of stroke-the only one of its kind in the U.S.

Based on these pre-clinical results, ArunA Biomedical plans to begin human studies in 2019, said Stice, who is also chief scientific officer of ArunA Biomedical. “Until now, we had very little evidence specific to neural exosome treatment and the ability to improve motor function,” said Stice. “Just days after stroke, we saw better mobility, improved balance and measurable behavioral benefits in treated animal models.”

Citation: Webb, Robin L., Erin E. Kaiser, Shelley L. Scoville, Tyler A. Thompson, Sumbul Fatima, Chirayukumar Pandya, Karishma Sriram, Raymond L. Swetenburg, Kumar Vaibhav, Ali S. Arbab, Babak Baban, Krishnan M. Dhandapani, David C. Hess, M. N. Hoda, and Steven L. Stice. “Human Neural Stem Cell Extracellular Vesicles Improve Tissue and Functional Recovery in the Murine Thromboembolic Stroke Model.” Translational Stroke Research, 2017.
doi:10.1007/s12975-017-0599-2.

Funding: ArunA Biomedical, Inc., Science and Technology Center Emergent Behaviors of Integrated Cellular Systems.

Adapted from press release by University of Georgia.

Research shows key role of FoxO proteins in osteoarthritis development

Research from scientists at The Scripps Research Institute explains why the risk of osteoarthritis increases as we age and offers a potential avenue for developing new treatments. The study’s findings suggest that FOXO proteins are responsible for the maintenance of healthy cells in the cartilage of our joints. The results are published in journal Science Translational Medicine.

“We discovered that FoxO transcription factors control the expression of genes that are essential for maintaining joint health,” says Martin Lotz, MD, a TSRI professor and senior author of the study. “Drugs that boost the expression and activity of FoxO could be a strategy for preventing and treating osteoarthritis.”

Previous research from Lotz’ lab showed that as joints age, levels of FoxO proteins in cartilage decrease. Lotz and his colleagues had also found that people with osteoarthritis have a lower expression of the genes needed for a process called autophagy. Autophagy is a cell’s way of removing and recycling its own damaged structures to stay healthy.

For the new study, researchers used mouse models with FoxO deficiency in cartilage to see how the FoxO proteins affect maintenance of cartilage throughout adulthood. The researchers noticed a striking difference in the mice with “knockout” FoxO deficiency. Their cartilage degenerated at much younger age than in control mice. The FoxO-deficient mice also had more severe forms of post-traumatic osteoarthritis induced by meniscus damage (an injury to the knee), and these mice were more vulnerable to cartilage damage during treadmill running.

The FoxO-deficient mice had defects in autophagy and in mechanisms that protect cells from damage by molecules called oxidants. Specific to cartilage, FoxO-deficient mice did not produce enough lubricin, a lubricating protein that normally protects the cartilage from friction and wear. This lack of lubricin was associated with a loss of healthy cells in a cartilage layer of the knee joint called the superficial zone.

These problems all came down to how FoxO proteins work as transcription factors to regulate gene expression. Without FoxO proteins running the show, expression of inflammation-related genes skyrockets, causing pain, while levels of autophagy-related genes plummet, leaving cells without a way to repair themselves. “The housekeeping mechanisms, which keeps cells healthy, were not working in these knockout mice,” Lotz explains.

To determine whether targeting FoxO has therapeutic benefits, the investigators used genetic approaches to increase FoxO expression in cells of humans with osteoarthritis and found that the levels of lubricin and protective genes returned to normal. The next step in this research is to develop molecules that enhance FoxO and test them in experimental models of osteoarthritis.

Citation: Matsuzaki, Tokio, Oscar Alvarez-Garcia, Sho Mokuda, Keita Nagira, Merissa Olmer, Ramya Gamini, Kohei Miyata, Yukio Akasaki, Andrew I. Su, Hiroshi Asahara, and Martin K. Lotz. “FoxO transcription factors modulate autophagy and proteoglycan 4 in cartilage homeostasis and osteoarthritis.” Science Translational Medicine 10, no. 428 (2018). doi:10.1126/scitranslmed.aan0746.

Research funding: NIH

Adapted from press release by The Scripps Research Institute.

Animal study finds MeXis gene protective against coronary artery disease

UCLA scientists have identified a gene called MeXis that may play a protective role in preventing heart disease. Their findings suggests that this gene acts within macrophages inside clogged arteries to help remove excess cholesterol from blood vessels by controlling cholesterol pump protein expression. Research is published in the journal Nature Medicine.

MeXis is an example of a “selfish” gene, one that is presumed to have no function because it does not make a protein product. However, recent studies have suggested that these so-called “unhelpful” genes can actually perform important biological functions without making proteins and instead producing a special class of molecules called long non-coding RNAs, or lncRNAs.

“What this study tells us is that lncRNAs are important for the inner workings of cells involved in the development of heart disease,” said Dr. Peter Tontonoz, senior author of the study. “Considering many genes like MeXis have completely unknown functions, our study suggests that further exploring how other long non-coding RNAs act will lead to exciting insights into both normal physiology and disease.”

In the study, researchers found that mice lacking MeXis had almost twice as many blockages in their blood vessels compared to mice with normal MeXis levels. In addition, boosting MeXis levels made cells more effective at removing excess cholesterol. In the next phase of the study, researchers will further explore how MeXis affects the function of cells in the artery wall and will test various approaches to altering MeXis activity. The researchers are interested in finding out if MeXis could be targeted for therapy of cardiovascular disease.

Citation: Sallam, Tamer, Marius Jones, Brandon J. Thomas, Xiaohui Wu, Thomas Gilliland, Kevin Qian, Ascia Eskin, David Casero, Zhengyi Zhang, Jaspreet Sandhu, David Salisbury, Prashant Rajbhandari, Mete Civelek, Cynthia Hong, Ayaka Ito, Xin Liu, Bence Daniel, Aldons J. Lusis, Julian Whitelegge, Laszlo Nagy, Antonio Castrillo, Stephen Smale, and Peter Tontonoz. “Transcriptional regulation of macrophage cholesterol efflux and atherogenesis by a long noncoding RNA.” Nature Medicine, 2018. doi:10.1038/nm.4479.

Funding: NIH/National Heart, Lung and Blood Institute, Burroughs Wellcome Fund Career Awards for Medical Scientists, UCLA Cardiovascular Discovery Fund, Lauren B. Leichtman and Arthur E. Levine Investigator Award.

Adapted from press release by the University of California Los Angles Health Sciences.

Animal studies show that naturally occurring peptide catestatin has potential as anti-obesity and type 2 diabetes treatment

Research by team from University of California San Diego School of Medicine shows that treating obese mice with catestatin (CST), a peptide naturally occurring in the body, showed significant improvement in glucose and insulin tolerance and reduced body weight.

In a study published in journal Diabetes, researchers identified catestatins’s role in the recruitment and function of macrophages in the liver as well as regulation of obesity-induced liver inflammation and insulin resistance.

“We have shown that an endogenous peptide, catestatin, can directly suppress glucose production from hepatocytes and can indirectly suppress lipid accumulation in liver as well as macrophage-mediated inflammation in obese mice,” said Sushil K. Mahata, PhD, professor of medicine at UC San Diego School of Medicine. “The net results are improved glucose tolerance and insulin sensitivity. Therefore, this peptide has immense potential for an anti-obesity reagent as well as a novel drug to treat type 2 diabetes.”

Treating obese mice with catestatin inhibited the recruitment of monocyte-derived macrophages to the liver and decreased inflammation, suggesting catestatin is an anti-inflammatory peptide. Catestatin treatment also lowered blood sugar and insulin levels to normal, and reduced fatty liver. Administering catestatin had no effect on insulin or glucose tolerance in control lean mice, showing that the effect of catestatin is restricted to obese animals. This difference may be explained by the reduced levels of normal catestatin in obese mice compared to the lean control animals. To confirm the importance of naturally occurring catestatin, the authors studied mice that lacked catestatin. These mice ate more and were heavier but lost weight when treated with catestatin. The researchers theorize that naturally occurring catestatin may help maintain body weight by suppressing hunger and enhancing glucose tolerance.

“The improved glucose and insulin sensitivity with catestatin treatment may be partly explained by the anti-inflammatory effects of catestatin on the liver,” said Mahata. “We have identified a novel pathway for suppression of liver glucose production that could be used to compensate for the loss of naturally occurring catestatin or to bolster its impact. But further studies are needed to uncover how catestatin suppresses liver inflammation to improve metabolism.”

Citation: Ying, Wei, Sumana Mahata, Gautam K. Bandyopadhyay, Zhenqi Zhou, Joshua Wollam, Jessica Vu, Rafael Mayoral, Nai-Wen Chi, Nicholas J.g. Webster, Angelo Corti, and Sushil K. Mahata. “Catestatin Inhibits Obesity-Induced Macrophage Infiltration and Inflammation in the Liver and Suppresses Hepatic Glucose Production Leading to Improved Insulin Sensitivity.” Diabetes, 2018. doi: 10.2337/db17-0788.

Funding:  Department of Veterans Affairs, American Heart Association, National Natural Science Foundation of China, Noland Scholarship.

Adapted from press release by University of California San Diego School of Medicine.