Mentor:  Igor Chesnokov, PhD, Associate Professor, Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, School of Medicine, 552A Kaul Human Genetics Building, 770 20th Street South, Birmingham, AL 35294.  205-934-6974 (office), 205-934-6975 (lab), 205-975-2188 (fax)  ichesnokov@uab.edu

Postdoctoral/Research Associate position is available to study the mechanisms of DNA replication and cell cycle progression in eukaryotes using human and Drosophila as model systems. Candidates with strong background in biochemistry, molecular and cell biology are encouraged to apply. Knowledge of Drosophila molecular genetics will be beneficial but is not required. Send CV and the names of three references to: Dr. Igor Chesnokov, University of Alabama, Department of Biochemistry and Molecular Genetics, Birmingham AL, 35294. E-mail: ichesnokov@uab.edu.

Postdocs in UAB News

  • REGARDS data show diabetics who use verapamil have lower glucose levels
    Lead author of paper published in Diabetes Research and Clinical Practice journal says, while causal relationship cannot be inferred, findings are “absolutely encouraging.”

    A new University of Alabama at Birmingham research paper published in the journal Diabetes Research and Clinical Practice shows for the first time that there is an association of verapamil use and lower fasting glucose levels in humans with diabetes. It is a promising finding at UAB, where the Comprehensive Diabetes Center is currently conducting a first-of-its-kind, JDRF-funded clinical trial using verapamil, a drug that researchers in the School of Medicine have shown completely reverses the disease in mice models.

    Yulia Khodneva M.D., Ph.D., a research associate and postdoctoral scholar in UAB’s Division of Preventive Medicine and junior member of the Comprehensive Diabetes Center, examined the association of calcium channel blockers and verapamil use with fasting serum glucose among almost 5,000 adults with diabetes who were part of the REGARDS study. The Reasons for Geographic and Racial Differences in Stroke project, sponsored by the National Institutes of Health, is a national study focusing on learning more about the factors that increase a person’s risk of having cardiovascular disease.

    The sample of diabetic adults included 1,484 calcium channel blocker users, of whom 174 were verapamil users. The findings showed that calcium channel blocker users had 5 mg/dL lower serum glucose compared to non-users. Verapamil users had on average 10 mg/dL lower serum glucose compared to calcium channel blocker non-users. And the numbers showed a substantially greater difference among insulin users who also took verapamil. Verapamil users who took insulin in combination with oral medication had a 24 mg/dL lower serum glucose, and verapamil users who took insulin alone to manage their diabetes showed a 37 mg/dL lower serum glucose.

    “This is a cross-sectional observational study unlike the current prospective randomized UAB verapamil clinical trial, so we can’t infer causal relationship between using verapamil and lower glucose levels; but we can say there is an association with lower glucose levels, and that is absolutely encouraging,” Khodneva said.

    About the verapamil clinical trial

    • Recruitment for the UAB verapamil clinical trial began in early 2015.
    • The trial will enroll 52 people between the ages of 19 and 45 within three months of receiving a diagnosis of type 1 diabetes. MORE ENROLLEES ARE NEEDED.
    • Patients enrolled will be randomized to receive verapamil or a placebo for one year while continuing with their insulin pump therapy.
    • Patients will receive a continuous glucose monitoring system that will enable them to measure their blood sugar 24 hours a day, seven days a week.
    • Talk to your primary care physician if you are experiencing excessive thirst, excessive urination or unwanted weight loss in association with fatigue.
    • For more information or to enroll, contact UAB at 205-934-4112 or T1DM@uab.edu. To speak to a physician, contact Fernando Ovalle, M.D., at 205-934-4171.
    • Support this and other diabetes research at UAB by visiting the Comprehensive Diabetes Center.

    Khodneva says the findings in the final subgroup, which used insulin alone and included participants who had mostly Type 1 or severe Type 2 diabetes, were quite striking.

    “The change in glucose for that group compared to those not taking verapamil — 37 mg/dL — is almost four times higher than when you look at the whole sample of diabetic adults,” Khodneva said. “That made us think that verapamil is predominantly active for participants who have Type 1 diabetes or those with Type 2 diabetes who have really damaged beta cells. There seems to be something that works on the structural level, especially for those who have stronger beta-cell damage.”

    “Dr. Khodneva has done a tremendous job analyzing these large data sets and discovering for the first time that verapamil use is associated with lower glucose levels in patients with diabetes,” said Anath Shalev, M.D., director of UAB’s Comprehensive Diabetes Center and principal investigator of the verapamil clinical trial. “Strikingly, the observed difference in glucose levels is comparable to an approximately 1 percent reduction in HbA1C and to what would be expected from the addition of an approved diabetes drug. Moreover, the large difference in glucose levels especially in the groups taking insulin is consistent with our underlying hypothesis that verapamil promotes functional beta-cell mass.”

    UAB announced its verapamil clinical trial in November 2014 and began enrolling patients in January 2015. The first results that will assess verapamil’s effectiveness on Type 1 diabetes are still approximately 18 months away.

    The trial is testing an approach different from any current diabetes treatment by focusing on promoting pancreatic beta cells, which produce insulin the body needs to control blood sugar. UAB scientists have proved through years of research that high blood sugar causes the body to overproduce a protein called TXNIP, which is increased within the beta cells in response to diabetes, but had never previously been known to be important in beta-cell biology. Too much TXNIP in the pancreatic beta cells leads to their death and thwarts the body’s efforts to produce insulin, thereby contributing to the progression of diabetes.

    But UAB scientists have also uncovered that verapamil, which is widely used to treat high blood pressure, irregular heartbeat and migraine headaches, can lower TXNIP levels by decreasing calcium concentration in the beta cells — to the point that, when mouse models with established diabetes and blood sugars above 300 milligrams per deciliter were treated with verapamil, the disease was eradicated. See an animation of how this works here.

    The trial will enroll 52 people between the ages of 18 and 45 who are within three months of receiving a diagnosis of Type 1 diabetes. More than 20 people have enrolled so far, and more participants are needed. For more information or to enroll, contact UAB at 205-934-4112 or T1DM@uab.edu.

  • UAB Psychology professor given early career award
    Faculty member honored for significant contributions to the field.

    Despina Stavrinos, Ph.D., has been selected to receive the Routh Early Career Award from the Society of Pediatric Psychology.

    This national award recognizes an early career member of the society who has made significant contributions to the field of pediatric psychology in research, clinical training and service.

    Stavrinos, an assistant professor in the College of Arts and SciencesDepartment of Psychology, studies distracted driving, with particular attention to at-risk populations.

    She serves as the director of the Translational Research for Injury Prevention, or TRIP, laboratory. The focus of the lab’s research is the prevention and control of unintentional injuries that result from motor vehicle crashes.

    The TRIP lab offers students at various levels of training, from high school to postdoctoral, and from various disciplines the opportunity to conduct high-quality behavioral research. Since its establishment in 2009, nearly 100 students have been trained under Stavrinos’ mentorship.

    The award will be presented at the Society of Pediatric Psychology’s annual conference in April.

  • UAB researchers work to unravel the complex genetic disease neurofibromatosis type 1
    One major goal is the discovery of new genotype/phenotype correlations — how a particular mutation indicates that some symptoms in patients are unlikely to develop with age.
    Ludwine Messiaen

    It is easy to tell a medical research story that has a simple and dramatic moment. But disease is often much more complex, and the work to understand it can be painstaking.

    A vivid example of that is seen in the UAB Medical Genomics Laboratory, headed by Ludwine Messiaen, Ph.D., professor of genetics. This lab offers clinical genetic testing for a broad array of common and rare genetic disorders. One of the most confounding is neurofibromatosis type 1.

    This can be a heartbreaking disease.

    Changes at puberty

    It usually starts with café-au-lait skin markings, so named because of their distinctive coloring, in an infant. But at puberty — already a challenging time in a person’s life, many patients develop benign skin tumors called neurofibromas that erupt as bumps across the body. Patients vary widely in their symptoms, which can include freckles near skin folds of the body, nodules in the eyes, tumors along the optic nerve, heart defects, anomalies of connective tissue or bones, developmental delay, intellectual disability, and learning problems.

    Patients show a broad clinical variability as they grow, and whether their case will be mild or severe cannot — in most cases — be predicted when the disease first appears. This leaves physicians and families uncertain about what symptoms will appear in a particular child as he or she nears puberty.

    Cafe-au-lait skin markings on the back of a young child

    Profusion of mutations

    This kaleidoscope of clinical signs is mirrored by an abundance of different mutations in the NF1 gene, responsible for the disease. The UAB Medical Genomics Laboratory has collected DNA and identified a pathogenic mutation in more than 7,800 unrelated neurofibromatosis type 1 patients. All have NF1 mutations, but meticulous examination has revealed so far more than 3,000 different mutations. These can be found in every part of the gene, and the mutational spectrum involves microdeletions, deletions or duplications that involve one or more exons, frameshift and nonsense mutations, and splice or missense mutations. Almost half of the NF1 patients carry a unique mutation found only in their specific family. Other mutations have been found in multiple unrelated families.

    Two searches

    From this complicated array of mutations and clinical symptoms, Messiaen and her colleagues have tried to answer two questions.

    First, can a particular mutation be correlated with the symptoms that will develop as the child grows? This is called a genotype/phenotype (DNA/symptoms) correlation, and only two have previously been found for neurofibromatosis type 1.

    “It’s important for people to know what may happen,” Messiaen said. “When a child is born with neurofibromatosis type 1, café-au-lait spots appear very shortly after birth; but other problems, more specifically the development of skin neurofibromas, typically appear around puberty. If a genotype/phenotype correlation exists for a particular mutation, it will help these families have some perspective of what the future will bring, and it will help families cope with the disease. If it is a mutation that takes away the heavy tumor burden at puberty, that information will relieve families, even though learning disabilities may still appear.”

    The second question for Messiaen and UAB postdoctoral trainee Meng-Chang “Jack” Hsiao, UAB Department of Genetics, is whether they could identify the likely mechanism that caused a group of mutations in which the DNA has been rearranged to create mix-ups that make the gene longer or shorter.

    Each question requires meticulous research. One means reaching out to patients, families and referring physicians around the nation and the world. The other is a molecular genetic detective story, pursued in the UAB lab.

    Messiaen and Meng-Chang "Jack" Hsiao are exploring the mechanisms behind the mutations seen in neurofibromatosis type 1.

    Seeking a correlation

    For the first question, Messiaen last year led a group of 74 researchers and clinicians from 58 centers in the discovery of just the third genotype/phenotype correlation ever found for neurofibromatosis type 1. They looked at 136 individuals who all had a missense mutation in the arginine moiety of neurofibromin, the protein encoded by the NF1 gene, at amino acid position 1,809. These mutations are the second-most-frequent ones seen in the UAB collection.

    To look for a correlation, the team had to gather detailed clinical symptomatic information for each of the neurofibromatosis patients, from patients, families, referral physicians and researchers in 24 U.S. states and Australia, Belgium, Brazil, Chile, the United Kingdom, India, Israel and Spain.

    In a paper published in the journal Human Mutation last year, they found that these patients have a distinct phenotype, Messiaen says. They had the café-au-lait marks, with or without the skin-fold freckling and Lisch eye nodules. But the patients did not develop the visible, disfiguring neurofibromas on their skin around puberty. However, there was a higher prevalence of blood flow obstruction from the heart to the lungs and a short stature. More than half had developmental delays and/or learning disabilities.

    Messiaen is calling for international collaboration to expand the study to a total of 250 mutations, which will provide the statistical power needed for patient case management by doctors. And in the next few years, she will focus on finding more genotype/phenotype correlations for other specific mutations.

    "If a genotype/phenotype correlation exists for a particular mutation, it will help these families have some perspective of what the future will bring, and it will help families cope with the disease."

    "If a genotype/phenotype correlation exists for a particular mutation, it will help these families have some perspective of what the future will bring, and it will help families cope with the disease."

    Chasing molecular clues

    For the second question, Hsiao, Messiaen and colleagues looked at NF1 copy-number variations — where the mutant gene is either longer or shorter than a normal NF1 gene — from 85 unrelated neurofibromatosis type 1 patients, along with two previously published copy-number variations. Ten of these were partial duplications within the NF1 gene, and 77 were deletions. Hsiao looked for specific nucleotide breakpoints in these variants — the places where the duplication or deletion begins or ends — that would be clues to how the changes occurred.

    The methods to examine these mutant genes include multiplex ligation-dependent probe amplification, array comparative genomic hybridization, breakpoint-spanning PCR and sequencing.

    “The most difficult challenge is to see how the rearrangements happen,” Hsiao said. “It’s really difficult to decipher.”

    In a paper published in The American Journal of Human Genetics last year, Hsiao found that DNA replication-based mechanisms — such as fork stalling and template switching, and microhomology-mediated break-induced replication — as well as serial replication stalling appear to be the major causes of the NF1 copy-number variants. In one complicated rearrangement, the DNA replication appeared to have stalled five times, with the stalled DNA strand then either invading forward or invading backward into another part of the NF1 gene. Hsiao also found that the mutant genes showed rearrangement hotspots that included one palindromic sequence and four Alu elements. Alu elements are short primate-specific repeats in the DNA; the human genome contains about 1 million copies of various Alu elements that make up almost 11 percent of the genome.

    Two sides to the research

    Messiaen says the two recent papers are “nice companions.”

    “They show two sides of research aspects of this laboratory,” she said. “One digs deeper into the mechanism of specific types of mutation, and one contributes to genotype/phenotype correlation.”

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UAB Research News

  • Study shows generic drugs match brand name drugs in treatment of epilepsy
    More evidence that generic medications are as effective as brand name drugs.

    A new multisite study shows that two approved generic medications for epilepsy had no detectable difference in clinical effects when compared to their brand name counterpart. The findings were published this week in an advance online edition ofthe Lancet Neurology.

    The study, led by investigators at the University of Cincinnati, looked at two generics for the drug lamotrigine, a prescription antiepileptic medication. The University of Alabama at Birmingham was one of eight institutions involved in the study, which showed that, as long as patients adhere to treatment, the two generics did not show any difference in their bioequivalence.

    “Consequently, it should give increased confidence to both clinicians and patients that existing regulations are providing generic drugs that can be safely substituted, even in cases where medicine is lifesaving,” said Michael Privitera, M.D., professor in the Department of Neurology, director of the Epilepsy Center at the University of Cincinnati Neuroscience Institute and the study’s lead author. “Patients can now feel safe about substituting generics (of their antiepileptic drug) without concerns of interactions or undesired effects.”

    The study included 35 adult patients with epilepsy who currently take lamotrigine, and looked at long-term dosing using two currently on-market epileptic generic drugs. The researchers took measures to ensure treatment adherence, a factor that can affect long-term trials. This trial used patient diaries, electronic medication monitoring and tablet counts to keep adherence to nearly 100 percent. The study found that patients on generics had no increase in seizure risk, nor an increase in side effects.

    “There is now increasing evidence that there is no significant difference between generic medications and brand name medications for most conditions.”

    “This study should change how the medical community and patients view generic medications,” said Jerzy Szaflarski, M.D., Ph.D., professor in the Department of Neurology at UAB and director of the UAB Epilepsy Center in the School of Medicine. “There is now increasing evidence that there is no significant difference between generic medications and brand name medications for most conditions.”

    The need for effective generics is essential to some patients who need daily medication to treat serious conditions like epilepsy. The FDA estimates $230 billion per year is saved by generic substitutions.

    Along with the University of Cincinnati and UAB, the study’s co-authors included researchers from Drake University, University of Madison-Wisconsin, University of Kansas Medical Center, Harvard Medical School, University of Pennsylvania, the office of research for the Food and Drug Administration, and the University of Rochester.

    This study was funded by the American Epilepsy Society, Epilepsy Foundation, and U.S. Food and Drug Administration. Privitera is president of the American Epilepsy Society. He does not cite any conflicts of interest.

  • Changes in shape and ‘squishiness’ can help drug-containing microcapsules reach tumors
    The properties of cubic or spherical shape and solid or elastic stiffness affect the fates of polymer microcapsules meant to carry chemotherapy to a tumor.

    University of Alabama at Birmingham researcher Eugenia Kharlampieva, Ph.D., makes polymer microcapsules meant to carry cancer drugs to the site of a tumor. Working in the UAB Department of Chemistry at the intersection of polymer chemistry, nanotechnology and biomedical science, she is creating novel “smart” particles that will provide controlled delivery for therapeutic drugs. Specifically, she has found that changes in shapes or elasticity of these tiny carriers greatly influence their ability to surmount the drug-delivery hurdles that lie between an injection into a vein and engulfment into a cancer cell.

    Alexander, JF; Kozlovskaya, V; Chen, J; Kuncewicz, T; Kharlampieva, E; and Godin, B; Cubical Shape Enhances the Interaction of Layer-by-Layer Polymeric Particles with Breast Cancer Cells. Advanced Healthcare Materials, 2015, Vol. 17, front cover. Copyright Wiley-VCH Verlag GmbH & Co. KGaA. Reproduced with permission.

    In a recent paper, Kharlampieva and colleagues compared four different microcapsules — rigid cubes or spheres, and elastic cubes or spheres — to see how they perform against three challenges. The first is avoiding engulfment by healthy macrophage immune system cells that act as lookouts and first defenders against foreign pathogens entering the body. The second is the ability to squeeze through the tiny openings in the walls of unhealthy blood vessels to reach tumor cells. The third is getting taken up by tumor cells, where they can deliver their chemotherapy payload.

    In the in vitro experiments, the team found clear winners. For the macrophage challenge, the elastic spheres and cubes were far better at avoiding engulfment compared with the solid spheres and cubes. This potentially means less harm to the healthy immune system cells and a longer half-life in the bloodstream for the elastic therapeutic microcapsules.

    “We want them to stay away from macrophages, which are like the clearing soldiers of the bloodstream,” Kharlampieva said. “We found that the hollow particles are much more elastic, and they are not taken up by macrophages, which is fantastic.”

    In the challenge of squeezing through tiny openings, the elastic spheres and cubes again were far better than the solid microcapsules. The walls of the microscopic blood vessels in tumors have openings that range between 300 nanometers to 1.2 micrometers. The researchers found that the elastic microcapsules, which are 2 micrometers wide, could squeeze through pores that were two to three times smaller than the diameters of the particles. And after squeezing through, the microcapsules regained their shapes as spheres or cubes.

    In tests of uptake into breast cancer cells, the cubes — whether solid or elastic — showed greater uptake, possibly because the flat walls have greater surface area contact with the cells.

    Thus, overall, the researchers write, “Our data show that elastic cubical capsules possess important biological characteristics, which can warrant their further development for cancer therapy.”

    The next step for Kharlampieva and her colleagues will be testing the biological significance, looking at how changes in shapes and elasticity affect the fates and destinations of these polymer microcapsules in the bloodstreams of mice.

    Laser scanning confocal microscopy image of SUM159 human breast cancer cells incubated with cubic capsules for 24 hours. Cell nuclei are stained blue, cell skeleton is stained green, and the capsules are labeled with a red fluorophore. Credit: E. KharlampievaDetails

    To manufacture the spheres and cubes, Kharlampieva and colleagues start with solid scaffolds — either a spherical particle of silicon dioxide or a cubic crystal of manganese carbonate. They then coat the particles with five bilayers of polymers, using tannic acid and poly(N-vinylpyrrolidone). For the solid microcapsules, they leave the scaffolds in place. For the elastic microcapsules, they remove the scaffolds with either acid or a chelating agent.

    The resulting microcapsules are water-soluble, nontoxic and biodegradable, which suits them for the job of controlled drug delivery, and the polymer walls of these shapes are just 50 nanometers thick. Their elasticity is measured with an atomic force microscope, and they are so small that a line of 12,700 of the microcapsules would measure 1 inch.

    Kharlampieva’s investigation of the effects of shape and elasticity comes from the simple observation that cells of the body that travel through the bloodstream are not spherical and are quite elastic.

    The paper, “Cubical shape enhances the interaction of layer-by-layer polymeric particles with breast cancer cells,” was published in Advanced Healthcare Materials, and the cover art features the research. UAB authors of the study are Kharlampieva, Veronika Kozlovskaya, Ph.D., and Jun Chen, all of the Department of Chemistry. Authors at the Houston Methodist Research Institute are Jenolyn Alexander, Thomas Kuncewicz and Biana Godin, Ph.D. Kharlampieva and Godin are the corresponding authors. Alexander and Kozlovskaya are co-first authors.

    Financial support came from NIH U54CA143837, NIH 1U54CA151668-01 and NSFCAREER1350370.

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