AHA Journals, Author Interviews, Genetic Research, Heart Disease, Lipids / 15.01.2015

Jean-Claude Tardif MD Professor of Medicine Director of the Research Centre Montreal Heart Institute Montreal, Quebec CanadaMedicalResearch.com Interview with: Jean-Claude Tardif MD Professor of Medicine Director of the Research Centre Montreal Heart Institute Montreal, Quebec Canada MedicalResearch.com: What is the background for this study? What are the main findings? Dr. Tardif: Epidemiological and mechanistic studies have suggested that high-density lipoproteins (HDL) could have beneficial cardiovascular properties. However, several medications targeting HDL have failed in recent clinical trials, including the CETP inhibitor dalcetrapib in the dal-Outcomes trial. We hypothesized that dalcetrapib would be beneficial in the subset of patients with the appropriate genetic profile. We conducted the pharmacogenomic analysis of approximately 6000 patients from the dal-Outcomes study which showed that patients with the AA genotype at a specific genetic location (rs1967309) of the adenylate cyclase (ADCY9) gene benefited from a 39% reduction in cardiovascular events including cardiovascular death, myocardial infarction, stroke, unstable angina and the need for coronary revascularization when treated with dalcetrapib compared to placebo. In contrast, patients with the GG genotype had a 27% increase in cardiovascular events. We then obtained confirmatory evidence from the dal-Plaque-2 imaging study which revealed that patients with the protective genotype (AA) had a reduction in their carotid artery wall thickness and that those with the genotype associated with clinical harm (GG) had an increase in their wall thickness. (more…)
Author Interviews, Genetic Research, PTSD, UCLA / 15.01.2015

Armen K. Goenjian, M.D., L.D.F.A.P.A., F.A.C.G.S. Research Professor of Psychiatry Department of Psychiatry and Biobehavioral Sciences David Geffen School of Medicine at UCLAMedicalResearch.com Interview with: Armen K. Goenjian, M.D., L.D.F.A.P.A., F.A.C.G.S. Research Professor of Psychiatry Department of Psychiatry and Biobehavioral Sciences David Geffen School of Medicine at UCLA Medical Research: What is the background for this study? Response: Post-traumatic stress disorder (PTSD) is a psychiatric disorder that develops after exposure to a traumatic event such as rape, war, natural disaster, and accident. Symptoms include recurrent intrusive traumatic memories, flashbacks, nightmares, hyper-vigilance, jumpiness, and anxiety. Dopaminergic and serotonergic systems have been implicated in PTSD. Catechol-O-methyltransferase (COMT) is an enzyme that degrades dopamine, an important brain neuro-hormone that regulates human behavior, thoughts and emotions.  Tryptophan hydroxylase is the rate limiting step in the synthesis of serotonin, another important neuro-hormone that regulates arousal, sleep, anxiety, and mood. This study evaluated the association of four COMT gene loci, and the joint effect of COMT and tryptophan hydroxylase 2 (TPH-2) genes on PTSD symptoms. (more…)
Author Interviews, BMC, Genetic Research, Heart Disease, Pharmacology / 12.01.2015

Caroline Attardo Genco, PhD Professor Department of Medicine, Section of Infectious Diseases Department of Microbiology Boston University School of Medicine Boston MA 02118MedicalResearch.com Interview with: Caroline Attardo Genco, PhD Professor Department of Medicine, Section of Infectious Diseases Department of Microbiology Boston University School of Medicine Boston MA MedicalResearch: What is the background for this study? What are the main findings? Dr. Genco: Atherosclerosis is a common cardiovascular disease associated with heart attack and stroke. Although it has been shown that a diet high in fat as well as exposure to certain bacteria can cause atherosclerosis (the buildup of fats, cholesterol, and other substances on artery walls which can restrict blood flow), we have for the first time identified distinct gene pathways that are altered by these different stimuli. One of these bacteria, Porphyromonas gingivalis, is found in the mouth of humans with periodontal disease. Another is the bacteria Chlamydia pneumoniae, which causes pneumonia. We found that even though these three different stimuli all cause atherosclerosis, the gene pathways are distinct depending upon stimulus. This is the first study that has performed side-by-side comparison of genome-wide gene expression changes to address this issue. In this study, we used four experimental groups to compare genome-wide expression changes in vascular tissue. The first group was subjected to Porphyromonas gingivalis, while the second group received Chlamydia pneumoniae. The third group was placed on a high-fat Western style diet, while the fourth group was the control group. In collaboration with the Clinical and Translational Science Institute (CTSI) at Boston University, we performed genome-wide microarray profiling and analysis of vascular tissue from all groups to reveal gene pathways altered in vascular tissue by each treatment group. These findings may explain how specific infections or high-fat diet may cause atherosclerotic plaques to undergo changes that affect their size and stability and may ultimately lead to a heart attack. (more…)
Author Interviews, Breast Cancer, Genetic Research, Nature / 11.01.2015

MedicalResearch.com Interview with: Dr. Pentao Liu PhD and Dr. Walid Khaled PhD Wellcome Trust Sanger Institute Cambridgeshire United Kingdom Medical Research: What is the background for this study? What are the main findings? Dr. Pentao Liu: The significance of this research is that it aims to tackle the worst type of breast cancer. Triple Negative Breast Cancer (TNBC) has the poorest patient survival rate compared to other forms of breast cancer.  At present there are no targeted therapies available for TNBC, leaving the non-specific chemotherapy as the only treatment option. In this study we identify a new key gene in  Triple Negative Breast Cancer which could potentially be inhibited for the targeted treatment of TNBC. In this study we report the identification of a novel gene for Triple Negative Breast Cancer. By analyzing genomics data from 3,000 patients we find BCL11A to be highly expressed in TNBC. We then demonstrate experimentally that upregulation of BCL11A drives tumour development while its downregulation leads to reduction in tumour size. In the experimental mouse model, inactivation of this gene completely abolishes breast tumour development. (more…)
Author Interviews, Breast Cancer, Genetic Research / 10.01.2015

Dr. Chao Cheng PhD Department of Genetics Geisel School of Medicine at Dartmouth Hanover 03755, NHMedicalResearch.com Interview with: Dr. Chao Cheng PhD Department of Genetics Geisel School of Medicine at Dartmouth Hanover 03755, NH   MedicalResearch: What is the background for this study? What are the main findings? Dr. Chao Cheng: Cancer survival prognosis—“How long do I have, Dr.?” is a topic of great importance to cancer patients and their families. While clinical and pathological variables, such as cancer type, stage, grade, and patient demographics, have long been used to predict survival outcomes, only recently have molecular signatures become incorporated into survival prediction. A molecular approach holds great promise for improving prediction accuracy and additionally elucidating mechanisms of disease, however it is fraught with difficulty due to assay “noise” and “big data” statistical issues, such as the multiple comparisons problem In this study, we began by analyzing transcription factor binding profiles across available cell lines. By restricting our analysis to transcription factors, DNA expression regulators known to be involved in tumor genesis, we reasoned that we could avoid many of the “big data” issues and achieve results that would make mechanistic and biological sense. We first employed a statistical method we described previously to calculate which genes were the major downstream targets of our transcription factors. With these targets identified, we then analyzed gene expression data using a bioinformatics method to infer the relative activity of each transcription factor based upon the overall expression levels of their gene targets. From here, we incorporated cancer survival data and examined how each transcription factor’s regulatory activity did, or did not, correlate with survival. The most prognostic transcription factor was E2F4, a member of the E2F family and a known regulator of the cell cycle. We therefore restricted our analysis to E2F4 and examined how its activity level impacted survival in breast cancer patients. We found that tumors with high E2F4 regulatory activity as compared to low E2F4 regulatory activity had much worse survival outcomes. These results were stable even after controlling for tumor stage, grade, patient age, and treatment, and were based on data from over 1900 patients across eight independent datasets. These results demonstrate that E2F4 is an independent and enhancing predictor of survival above the currently examined variables. (more…)
Author Interviews, Case Western, Genetic Research / 05.01.2015

Michael A. Weiss, MD, PhD The Cowan-Blum Professor and Chairman of the Department of Biochemistry Distinguished Research Professor andMedicalResearch.com Interview with: Michael A. Weiss, MD, PhD The Cowan-Blum Professor and Chairman of the Department of Biochemistry Distinguished Research Professor and Professor of Medicine in the Endocrine Division at the Case Western Reserve School of Medicine in Cleveland, Ohio. Joseph Racca Researcher and graduate student Department of BiochemistryJoseph Racca Researcher and graduate student Department of Biochemistry Case Western Reserve School of Medicine in Cleveland, Ohio. Medical Research: What is the background for this study? What are the main findings? Response: The function of the gene responsible for male differentiation, sex-determining region of the Y chromosome (SRY), was first demonstrated in transgenic mouse models by P. Koopman, R. Lovell-Badge and colleagues in the early 1990s. These findings were corroborated by identification of mutations in human SRY that are associated with human sex reversal: XY, 46 gonadal dysgenesis leading to somatic sex reversal (Swyer’s Syndrome). Such mutations may occur spontaneously in spermatogenesis or be inherited. The characterization of the molecular defects associated with these mutations has unmasked novel biological and biochemical activities of SRY. More broadly, such studies have also increased our understanding of an entire family of related transcription factors (Sry-box related; SOX), which broadly function in metazoan development (from worms, fish and flies to mammals). Within human SRY, the majority of clinical mutations occur in the region of the protein responsible for specific DNA binding and DNA bending, the primary molecular actions of SRY at target genes. Our study bridges structure (i.e., protein folding and stability) and function (i.e., transcriptional activation of target genes and related cell-biological processes such as trafficking and proteosomal degradation). In our current study, we highlighted the importance of a structural scaffold in human SRY, specifically a key single amino acid that buttresses the unique L-shape structure of this domain. The mutation of interest represents a “perfect storm” leading to deleterious effects on multiple activities, including specific DNA binding, cellular localization, and both protein and cellular stability (lifetime), among other properties, together leading to sex reversal and cancer (gonadoblastoma) in the proband patient. Our integrated multi-disciplinary approach allowed us to characterize these various facets of SRY in the context of its biological site of action: the pre-Sertoli cell in an embryonic gonadal ridge just prior to its morphological differentiation into a testis. We are grateful to Prof. Patricia K. Donahoe (Harvard Medical School and the Massachusetts General Hospital), who generously provided this micro-dissected pre-Sertoli cell line. (more…)
Author Interviews, Genetic Research, Neurological Disorders, PNAS, Scripps / 26.12.2014

Elizabeth A. Thomas, Ph.D. Associate Professor Department of Molecular and Cellular Neuroscience The Scripps Research InstituteMedicalResearch.com Interview with: Elizabeth A. Thomas, Ph.D. Associate Professor Department of Molecular and Cellular Neuroscience The Scripps Research Institute   Medical Research: What is the background for this study? What are the main findings? Response: Increasing evidence has demonstrated that epigenetic factors can profoundly influence gene expression, and in turn, influence resistance or susceptibility to disease.  Epigenetic drugs, such as histone deacetylase (HDAC) inhibitors, are finding their way into clinical practice, and are being proposed for therapeutic use in several neurological disorders.  Our previous studies have shown that selective HDAC inhibitors can cause beneficial effects in mouse models of Huntington’s disease, improving symptoms, and reducing severity of the disease.  Our current studies show that one such compound can alter DNA methylation, an epigenetic mark that can be inherited, leading to changes in gene expression that are seen in the parent mouse exposed directly to the drug, as well as in offspring from the drug-treated male mice.  Concurrent with these changes, we observed that offspring from drug-treated males shown improved disease symptoms, showing a delay in disease onset and a reduction of motor and cognitive symptoms that included improved performance in tests of balance, speed and memory. These finding have significant implications for human health as they enforce the concept that ancestral drug exposure may be a major molecular factor that can affect disease outcome in a subsequent generation.  One exciting aspect of our study is that the parental drug treatment made the offspring better, not worse, like other compounds known to cause transgenerational effects. (more…)
Author Interviews, Breast Cancer, JNCI / 21.12.2014

MedicalResearch.com Interview with: Dr Ranjit Manchanda Consultant Gynaecological Oncologist, St Bartholomew’s Hospital, London, UK Honorary Sr Lecturer, Women’s Cancer, EGA Institute for Women's Health, University College London, UK  and Professor Ian Jacobs Vice President, The University of Manchester Dean & Head School of Medicine Faculty of Medical & Human Sciences, Director MAHSC (Manchester Academic Health Science Centre) Medical Research: What is the background for this study? What are the main findings? Dr. Jacobs:  Background- Women carrying a BRCA1/2 gene alteration have a very high risk of developing breast and ovarian cancer and men carrying this alteration have an increased risk of prostate and breast cancer. Approximately 45-65% women who have this inherited genetic change will develop breast cancer and 15-35% ovarian cancer. They also have a 50% chance of passing these genes on to their children. At risk individuals can access available options of screening and prevention through the National Health Service (NHS). Some population groups across the world are known to have a higher frequency of BRCA 1/2 gene alterations than others. One example is Ashkenazi Jews who have a 1 in 40 likelihood of having a BRCA1/2 gene alteration. This is 10-20 times higher than in the general non-Jewish population. At present in the UK, genetic testing is available within the NHS to individuals who have a strong family history of cancer. However, many people are not aware of their family history or its significance and do not seek advice. Many other individuals with BRCA1/2 gene alterations do not have a family history at all. The current approach misses a large number of people at risk who could benefit from knowing about their BRCA 1/2 mutation status and the ability to access opportunities for prevention or screening. In order to address this the GCaPPS study has investigated the best method of screening for risk of inherited (familial) cancer by exploring the alternative approach of offering the genetic test to all men and women >18 years in the Ashkenazi Jewish population. It does so by comparing the benefits and disadvantages of: (i) The current system of testing only those with a family history and (ii) The new option of testing everyone in the population. Main Findings: Over half of the BRCA1/BRCA2 carriers detected did not give a strong family history of cancer and would not have been identified by current family history based testing criteria used in the NHS (National Health Service) in the UK and most health systems internationally. Reassuringly population-based genetic testing in Ashkenazi Jews did not adversely affect short term psychological health or quality-of-life. A health economic analysis indicated that population-based screening for BRCA-mutations in Ashkenazi Jewish women ≥30years would be highly cost-effective compared to the traditional family history based approach. Such an approach if implemented could reduce the incidence of and deaths from breast and ovarian cancer as well as reducing cost and save the NHS funds. (more…)
Author Interviews, Cognitive Issues, Genetic Research, JAMA / 13.12.2014

David H. Ledbetter, Ph.D., FACMG Executive Vice President & Chief Scientific Officer, Geisinger Health System Danville, PA 17822MedicalResearch.com Interview with: David H. Ledbetter, Ph.D., FACMG Executive Vice President & Chief Scientific Officer, Geisinger Health System Danville, PA 17822 Medical Research: What is the background for this study? What are the main findings? Dr. Ledbetter: One of the biggest challenges in clinical care and research of children with autism and related neurodevelopment disorders is the remarkable clinical variability between individuals. This heterogeneity is reduced, but still significant, when considering individuals who have neurodevelopment disorders due to the identical genetic mutation such as deletion 16p11.2. We proposed that family background, genetic or environmental, may contribute to the variability in cognitive, behavioral and motor performance profiles of children with a sporadic (new) mutation in 16p11.2. Our study confirmed that a significant portion of the clinical variability seen in these children is due to the performance level of their parents and unaffected siblings and suggested that this may be due in part to genetic background effects as these traits are all known to have very high heritability. (more…)
Author Interviews, Genetic Research, NEJM, NIH / 13.12.2014

Dr. Constantine A. Stratakis, M.D., D.Sc National Institutes of Health, Clinical Research Center Bethesda, MD 20892-1862MedicalResearch.com Interview with: Dr. Constantine A. Stratakis, M.D., D.Sc National Institutes of Health, Clinical Research Center Bethesda, MD 20892-1862 Medical Research: What is the background for this study? What are the main findings? Dr. Stratakis: We have been working for years on the genetics of pituitary tumors in association with other conditions. A few years ago (attached), we studied for the first time a series of pediatric giants that we sequenced for then known genes. We found a few MEN1 and AIP mutations but all mutations were present in older kids with gigantism. This left out the youngest among the giants without any genetic defect. This was the first time I realized that I was dealing with a different disease. We started looking for additional genetic defects and when we found the Xq26 microduplications in 3 kindreds. We contacted the custodians of the largest series in the world - Dr. Beckers in Liege. He screened his cases, once we gave him the coordinates, and boom - it was there... The most significant thing here is that this is a new disease really: the early pediatric gigantism is almost exclusively due to Xq26 microduplications unless it is part of a family with another syndrome (AIP, MEN1, Carney complex). If there is no family history and you are dealing with a toddler with gigantism, based in these data, there is a more than 80% chance of having an Xq26 defect. This is pretty amazing! In addition, assuming that GPR101 is the responsible gene (which needs to be confirmed with additional studies) this identifies a new molecular pathway of increasing growth hormone secretion, most likely due to upregulation of GHRH - all of this needs to be confirmed in further human and animal studies. The Xq26 genomic micro-arrangements (which contain the GPR101, but also 3 other genes) is the big news here... (more…)
Author Interviews, Genetic Research, Memory / 09.12.2014

Sandra Barral Rodriguez, Ph.D Assistant Professor G. H. Sergievsky Center & Taub Institute Columbia University Medical Center New York, NY 10032MedicalResearch.com Interview with: Sandra Barral Rodriguez, Ph.D Assistant Professor G. H. Sergievsky Center & Taub Institute Columbia University Medical Center New York, NY 10032 Medical Research: What is the background for this study? What are the main findings? Dr. Barral: We already know that there is a substantial genetic contribution to the variability observed in different cognitive tasks including memory performance. Previous work reported heritability estimates for episodic memory ranging between 30% and 60%. However, we can’t fully explain why some individuals demonstrate a better memory performance in late life, while others do not. We have previously defined a cognitive endophenotype based on exceptional episodic memory performance (EEM) and demonstrated that there is a familial aggregation of EEM in families selected on their basis of their exceptional survival, the Long Life Family Study. We performed genome-wide linkage analysis of long-lived families selected on the basis of their exceptional episodic memory and the follow-up SNP association analysis with episodic memory in four independent cohorts of more than 4,000 non-demented elderly cohorts. Our results provide strong evidence for potential candidate genes related to exceptional episodic memory on 6q24. (more…)
Author Interviews, Diabetes, Heart Disease / 07.12.2014

Simin Liu, MD, ScD, Professor of Epidemiology School of Public Health, Professor of Medicine The Warren Alpert School of Medicine Director, Molecular Epidemiology and Nutrition Brown UniversityMedicalResearch.com Interview with: Simin Liu, MD, ScD, Professor of Epidemiology School of Public Health, Professor of Medicine The Warren Alpert School of Medicine Director, Molecular Epidemiology and Nutrition Brown University MedicalResearch: What is the background for this study? What are the main findings? Dr. Liu: Cardiovascular Disease (CVD) and type 2 diabetes (T2D) are highly heritable and share many risk factors and show ethnic-specific prevalence. Nevertheless, a comprehensive molecular-level understanding of these observations is lacking. We conducted a comprehensive assessment of whole genome assessment using network-based analysis in >15,000 women and identified eight molecular pathways share in both diseases as well as several “key driver” genes that appear to form the gene networks in which these pathways connect and interact. (more…)
Alcohol, Author Interviews, Nature, University Texas / 05.12.2014

MedicalResearch.com Interview with: R. Dayne Mayfield PhD and Sean Farris Post Doc Fellow Harris Lab Waggoner Center for Alcohol and Addiction Research University of Texas at Austin MedicalResearch: What is the background for this study? Response: Alcoholism is psychiatric disorder adversely affecting the health of millions of individuals worldwide. Despite considerable research efforts, alcoholism cannot be attributed to any individual gene. We sought out to identify coordinately regulated gene networks, rather than a single candidate gene, that may be collectively driving the consumption of alcohol. (more…)
Author Interviews, General Medicine, Genetic Research, Nature / 03.12.2014

Prof Dr Isabelle Mansuy Lab of Neuroepigenetics University/ETH Zürich Brain Research Institute Zürich, SwitzerlandMedicalResearch Interview with: Prof Dr Isabelle Mansuy Lab of Neuroepigenetics University/ETH Zürich Brain Research Institute Zürich, Switzerland   MedicalResearch: What is the background for this study? What are the main findings? Prof. Mansuy: It is recognised that being exposed to traumatic stress in early life increases the susceptibility to psychiatric and metabolic diseases later in life. This is true for people directly exposed but also for their progeny across generations. It is also known that sometimes, stress exposure in early life can help an individual develop response strategies and be better prepared for later stressful experiences. The mechanisms of such beneficial effects and the question of whether they can be transmitted or not are not known. This study in mice was designed to answer these questions. The main findings are that exposure to traumatic stress of mouse newborns makes the animals and their progeny more efficient in challenging tasks when adult. For instance, they are more able to adapt to rules that change in a complex task to get a water ration when they are thirsty. This suggests more adaptive behaviours in challenging situations that are transmitted across generation. The study identifies the mineralocorticoid receptor, a stress hormone receptor in the brain, as an important molecular mediator of this effect and demonstrates that its expression is altered in the brain by epigenetic mechanisms. (more…)
Allergies, Author Interviews, Genetic Research / 28.11.2014

Dr. Hakon Hakonarson MD PhD The Center for Applied Genomics, The Children’s Hospital of Philadelphia Department of Pediatrics, The Perelman School of Medicine, University of Pennsylvania Philadelphia, Philadelphia, PennsylvaniaMedicalResearch.com Interview with: Dr. Hakon Hakonarson MD PhD The Center for Applied Genomics, The Children’s Hospital of Philadelphia Department of Pediatrics, The Perelman School of Medicine, University of Pennsylvania Philadelphia, Philadelphia, Pennsylvania Medical Research: What is the background for this study? What are the main findings? Dr. Hakonarson: We have built the world’s largest pediatric biobank at the Center for Applied Genomics at CHOP. Eosinophilic esophagitis (EoE) is among the projects we have sampled in collaboration with the EoE Center in collaboration with Dr. Spergel. We have nearly 1,000 samples now of this relatively rare disorder, which is now well powered for GWAS.  We previously  reported association of the TSLP locus with Eosinophilic esophagitis. Here we report genome-wide significant associations at four additional loci; c11orf30 and STAT6, which have been previously associated with both atopic and autoimmune diseases, and two EoE-specific loci, ANKRD27 that regulates the trafficking of melanogenic enzymes to epidermal melanocytes and CAPN14, that encodes a calpain whose expression is highly enriched in the esophagus in EoE.  This discovery not only improves our understanding of the pathobiology of  EoE, but also represents novel targets for the development of new therapies to treat the disease. (more…)
Author Interviews, BMJ, Genetic Research, Vitamin D / 19.11.2014

MedicalResearch.com Interview with: Børge G Nordestgaard, MD, DMSc Professor, University of Copenhagen Chief Physician, Herlev Hospital, Copenhagen University Hospital Dept. Clinical Biochemistry Herlev Ringvej Herlev, Denmark Medical Research: What is the background for this study? What are the main findings? Prof. Nordestgaard: Many people take vitamin D supplements with the hope of reducing morbidity and mortality. However, it is unclear whether low vitamin D per se is a direct cause of increased mortality or whether it is simply a marker of poor lifestyle in general and/or underlying hidden disease. Our study involved 95,766 white participants of Danish descent from three cohorts in Copenhagen, who had genetic variants known to affect vitamin D levels. We found that genetically low vitamin D levels were associated with increased all-cause mortality, cancer mortality, and other mortality, but not with cardiovascular mortality. This is important as such genetics studies cannot be explained by poor lifestyle or hidden disease, as neither can change your genes. (more…)
Author Interviews, Genetic Research, Nature, NYU / 06.11.2014

Leslie Mitchell, PhD New York University Langone Medical Center Boeke Lab, Institute for Systems Genetics NY NY, 10016MedicalResearch.com Interview with: Leslie Mitchell, PhD New York University Langone Medical Center Boeke Lab, Institute for Systems Genetics NY NY, 10016 Medical Research: What is the background for this study? What are the main findings? Dr. Mitchell: One of our major interests is building synthetic chromosomes. Typically we construct synthetic chromosomes using a bottom-up approach, first designing the sequence in silico and then synthesizing and piecing together the DNA to build the designer molecule. While eukaryotic chromosomes are usually linear in structure, oftentimes we build our designer synthetic chromosomes as circular molecules to take advantage of cloning technologies available in E. coli, an organism that tolerates only circular chromosomes. We developed the telomerator as a means by which to convert circular synthetic chromosomes into linear molecules, which more closely resemble the native chromosomes found in eukaryotic cells. We discovered that the telomerator is an extremely effective tool for generating linear derivatives of circular synthetic chromosomes. There are two main reasons for this.
  • First, the action of the telomerator can be assessed using a simple phenotypic assay so it is easy to differentiate cells that encode linear synthetic chromosomes from those with the circular format.
  • Second, the telomerator encodes ‘telomere seed sequences’ that are exposed and recognized by the cell upon linearization, thus the ends of a newly linearized chromosome are protected, which ensures its stability over generations. We put the telomerator to the test by integrating it in 54 different positions on a circular synthetic yeast chromosome called synIXR (Dymond et al. 2011). In 51 of the 54 positions we could successfully linearize the synIXR chromosome and recover viable cells, however many of the different linear derivatives conferred growth defects. We determined the mechanism underlying both the growth defects and lethality associated with linearization to be telomere position effect. In other words, when essential genes were re-positioned near telomeres their reduction in expression due to subtelomeric silencing was detrimental to the cell.
(more…)
Alcohol, Author Interviews, Genetic Research / 05.11.2014

Victor M. Karpyak, M.D., Ph.D. Medical Director, Intensive Addiction Treatment Program Director, Mayo Clinic Addiction Services Consultant, Department of Psychiatry and Psychology Assistant Professor of Psychiatry Mayo Clinic College of Medicine MedicalResearch.com Interview with: Victor M. Karpyak, M.D., Ph.D.  Medical Director, Intensive Addiction Treatment Program Director, Mayo Clinic Addiction Services Consultant, Department of Psychiatry and Psychology Assistant Professor of Psychiatry  Mayo Clinic College of Medicine Medical Research: What is the background for this study? Dr. Karpyak: The staggering costs of alcohol use disorders call for the development and implementation of evidence-based treatment strategies. Several medications (acamprosate, naltrexone, and disulfiram) were approved for treatment of alcohol use disorders; yet, only a fraction of patients respond to each medication. Clearly, response predictors are needed to improve treatment efficacy and personalize recommendations for treatment selection. It is expected that pharmacogenomic research will aid the discovery of such predictors. (more…)
Author Interviews, Genetic Research / 24.10.2014

Dr. Toomas Kivsild PhD Department of Archaeology and Anthropology University of Cambridge, CambridgeMedicalResearch.com Interview with: Dr. Toomas Kivsild PhD Department of Archaeology and Anthropology University of Cambridge, Cambridge Medical Research: What is the background for this study? What are the main findings? Dr. Kivsild: Native populations of Siberia are known to have certain physiological characteristics such as high basal metabolic rate, and high blood pressure and low levels of serum lipids, that have been explained as traits that have evolved as a consequence of the adaptation of Siberians to their cold environment. Genetic basis of cold adaptation is still poorly understood. In our previous study using genome-wide genotyping scans we detected a 3 Mbp region of high haplotype homozygosity in chromosome 11 as a candidate of strong positive selection in Northeast Siberians. There were 79 protein coding genes mapping to this homozygosity region but we could not determine which of the genes was driving the signal we observed. In this forthcoming paper we have used high coverage whole genome sequences from 25 individuals from Northeast Siberia and we were able to determine the most likely SNP that is responsible for the high haplotype homozygosity in the chromosome 11 in Northeast Siberians maps to CPT1A gene which is a key regulator of long-chain fatty-acid oxidation in mitochondria. What makes this finding most interesting is that the same SNP had previously been found in Greenland and Canadian Inuits in association with high infant mortality and hypoketotic hypoglycemia. There are only a few other similar cases, like the sickle cell and APOL1 alleles, where disease associated genetic variants may have risen to high frequency in modern day populations due to the adaptive advantage they have presented in the past populations. (more…)
Author Interviews, Bipolar Disorder, Genetic Research, Nature / 21.10.2014

Edward I. Ginns, MD, PhD, Director Program in Medical Genetics and Lysosomal Disorders Treatment and Research Program University of Massachusetts Medical School Reed Rose Gordon Building, Room 137 Shrewsbury, MA 01545MedicalResearch.com: Interview with: Edward I. Ginns, MD, PhD, Director Program in Medical Genetics and Lysosomal Disorders Treatment and Research Program University of Massachusetts Medical School Reed Rose Gordon Building, Room 137 Shrewsbury, MA 01545 Medical Research: What are the main findings of the study? Dr. Ginns: Our study identified that sonic hedgehog signaling, an important brain pathway, is involved in bipolar affective disorder. This finding shows a mechanism and provides new targets for drug development. It suggests that sonic hedgehog signaling can be modulated to help manage bipolar symptoms in adults by using drugs already being studied in clinical trials for other medical conditions. The new findings were uncovered by decades of translational research in the Old Order Amish families of Pennsylvania, where in a few special families in the Amish Study there is a high incidence of both bipolar disorder and a rare genetic dwarfism, Ellis van‐Creveld (EvC) syndrome. No person with EvC had bipolar disorder despite forty years of documented research across multiple generations, suggesting that the genetic cause of this rare dwarfism was protective of bipolar affective disorder. (more…)
Author Interviews, Diabetes, Diabetologia, Exercise - Fitness, Genetic Research / 01.10.2014

Dr. Yann C Klimentidis, PhD Assistant professor of Epidemiology and Biostatistics Mel and Enid Zuckerman College of Public Health University of Arizona Medical CenterMedicalResearch.com Interview Invitation with: Dr. Yann C Klimentidis, PhD Assistant professor of Epidemiology and Biostatistics Mel and Enid Zuckerman College of Public Health University of Arizona Medical Center   Medical Research: What are the main findings of the study? Dr. Klimentidis: The main finding is that the association of physical activity with type-2 diabetes risk is weakest among those who are at high genetic risk for type-2 diabetes. Furthermore, we find that this trend is stronger among women as compared to men, and that it appears to be driven mainly by genetic risk to insulin resistance, as opposed to genetic risk for reduced beta-cell function. (more…)
Author Interviews, Genetic Research, Nature, Prostate Cancer / 18.09.2014

Dr. Jyotsna Batra QUT Institute of Health and Biomedical Innovation's Queensland University of Technology Queensland, AustraliaMedicalResearch.com Interview with: Dr. Jyotsna Batra QUT Institute of Health and Biomedical Innovation's Queensland University of Technology Queensland, Australia   Medical Research: What are the main findings of the study? Dr Batra: Prostate cancer is a disease with upto 40% genetic component. Previous Genome-wide association studies have identified 77 risk loci associated with prostate cancer. This study is further extension of previous GWASs and also involved meta-analysis of multi-ethnic populations. Through this large study involving approximately 90,0000 individuals, 23 new susceptibility loci were identified to be associated with prostate cancer, 15 variants were identified among men of European ancestry, 7 were identified in multi-ancestry analyses and 1 was associated with early-onset prostate cancer. (more…)
Author Interviews, Cancer Research, Genetic Research, University of Pennsylvania / 12.09.2014

Renata Afi Rawlings-Goss, Ph.D. Postdoctoral Fellow Tishkoff Lab, University of PennsylvaniaMedicalResearch.com Interview with: Renata Afi Rawlings-Goss, Ph.D. Postdoctoral Fellow Tishkoff Lab, University of Pennsylvania   Medical Research: What are the main findings of the study? Dr. Rawlings-Goss: We found genetic mutations in key gene regulators that have been linked to ethnic disparities in cancer. Our investigation identified more than 30 previously undescribed mutations in important regulatory molecules called microRNAs. Individual microRNA molecules can regulate large numbers of genes in some cases over 6000 genes at once. Therefore, mutations in these genes have been linked to numerous diseases. By and large, however, microRNA mutations have not been studied in people of diverse ethnic backgrounds. (more…)
Author Interviews, Breast Cancer, Genetic Research, NEJM / 07.08.2014

Dr Marc Tischkowitz MD PhD University Lecturer (Associate Professor) and Honorary Consultant Physician in Medical Genetics Department of Medical Genetics, University of CambridgeMedicalResearch.com Interview with: Dr Marc Tischkowitz MD PhD University Lecturer (Associate Professor) and Honorary Consultant  Physician in Medical Genetics Department of Medical Genetics, University of Cambridge Medical Research: What are the main findings of the study? Dr. Tischkowitz: The PALB2 gene was first identified in 2006 and linked to breast cancer in 2007 but until now we have not had good breast cancer risk estimates for women who have inherited PALB2 mutations. This study was started in 2009 by an group of research institutions (The PALB2 Interest Group) in Canada, US, Europe (UK, Belgium, Greece, Italy, Finland) and Australia. We studied 362 individuals with PALB2 mutations from 154 families. We found that awomen with a PALB2 mutation will on average have a 35% risk of developing breast cancer by the age of 70, rising to 58% if there is a strong family history. Our study will help clinicians to better advise and manage such women. There are several new aspects.
  • It is by far the largest study to date and provides the most accurate risk estimates for PALB2 mutation carriers.
  • It shows that the breast cancer risk is modified by the family history. (more…)
Author Interviews, Genetic Research, JCEM, Weight Research / 31.07.2014

Dr. Agatha van der Klaauw, PhD Wellcome Trust Postdoctoral Clinical Fellow Wellcome Trust-MRC Institute of Metabolic Science University of Cambridge Metabolic Research Laboratories Addenbrooke's Hospital Cambridge, United KingdomMedicalResearch.com Interview with: Dr. Agatha van der Klaauw, PhD Wellcome Trust Postdoctoral Clinical Fellow Wellcome Trust-MRC Institute of Metabolic Science University of Cambridge Metabolic Research Laboratories Addenbrooke's Hospital Cambridge, United Kingdom   Medical Research: What are the main findings of the study? Dr. van der Klaauw: Obesity occurs when we eat more calories than we burn which is often easy to do as many foods are highly palatable and high in calories. Highly palatable foods such as chocolate trigger signals in the brain that give a feeling of pleasure and reward (sometimes called cravings) which can contribute to overeating. These signals are processed in the reward centres in the brain, where sets of neurons release chemicals such as dopamine. However, very little is known about whether the reward centres of the brain work differently in some people who are overweight. In this study, we were interested in studying overweight people who had a problem with the melanocortin 4 receptor (MC4R) gene. About 1% of obese people have a problem in this gene which contributes to weight gain from a young age. We compared three groups of people: people who were overweight due to a problem in the MC4R gene, people who were overweight but the gene was normal and some people who were normal weight. We performed functional Magnetic Resonance Imaging (fMRI) scans to look at how the reward centres in the brain were activated by pictures of appetizing food such as chocolate cake compared to bland food such as rice or broccoli and non-food items such as staplers. We found that in normal weight people, the reward centres are activated (light up) when they are shown pictures of cake or chocolate and the same was seen in overweight people with a problem in the MC4R gene. But we found that the reward centres were underactive in overweight volunteers (in whom the gene was normal). (more…)
Author Interviews, Genetic Research, Mental Health Research / 30.07.2014

dr_zachary_kaminskyMedicalResearch.com Interview with: Zachary A. Kaminsky, Ph.D. Assistant Professor Johns Hopkins University School of Medicine Department of Psychiatry Baltimore, MD, 21205 Medical Research: What are the main findings of the study? Dr. Kaminsky: A DNA methylation increase at the SKA2 gene was identified and observed across three post mortem brain tissue cohorts and was associated with suicide. The DNA methylation at the SKA2 gene was associated with lower gene expression of the gene. The same association was found in blood allowing us to attempt to predict suicidal behaviors in living individuals. (more…)
Author Interviews, Breast Cancer, Genetic Research, Nature / 23.07.2014

MedicalResearch.com Interview with Dr Lim Weng Khong Research Fellow, National Cancer Centre Singapore. Medical Research: What are the main findings of the study? Dr Lim Weng Khong: This study uncovered the genetic cause fibroadenomas, which are very common benign breast tumours in women. The team from National Cancer Centre Singapore, Singapore General Hospital and Duke-NUS Graduate Medical School identified a critical gene called MED12 that has frequent durations in a remarkable 60 per cent of fibroadenomas studied. Their findings have been published in the top-ranked journal Nature Genetics. (more…)
Author Interviews, Gastrointestinal Disease, Genetic Research, NEJM, Pediatrics / 03.07.2014

Dr. Daniel AgardhMedicalResearch.com Interview with: Dr. Daniel Agardh M.D., Ph.D Department of Pediatrics Diabetes and Celiac Disease Unit Skåne University Hospital Malmo, Sweden, MedicalResearch: What are the main findings of the study? Dr. Agardh: In this study, we stratify the risk of celiac disease among children according to their HLA genotype and country of residence. We confirm that HLA-DQ2/2 genotype is the major risk factor for early celiac disease, but also show how the risk differs between the participating countries despite of sharing similar HLA risk. This points to the direction of an interaction between HLA and the environment that eventually lead to an autoimmune response in genetic susceptible children. (more…)
Author Interviews, Diabetes, Genetic Research, Nature / 30.06.2014

Dr. Domenico Accili MD Professor of Medicine Department of Medicine Columbia University College of Physicians and Surgeons New York, New York 10032MedicalResearch.com: Interview with Dr. Domenico Accili MD Professor of Medicine Department of Medicine Columbia University College of Physicians and Surgeons New York, New York 10032 MedicalResearch: What are the main findings of the study? Dr. Accili: By switching off a single gene (foxo1), scientists at Columbia University’s Naomi Berrie Diabetes Center have converted human gastrointestinal cells into insulin-producing cells, demonstrating in principle that a drug could retrain cells inside a person’s GI tract to produce insulin. (more…)
ADHD, Author Interviews, Genetic Research, Nature / 19.06.2014

Michele Jacob, Ph.D. Professor of Neuroscience Sackler School of Graduate Biomedical Sciences Tufts UniversityMedicalResearch.com Interview with Michele Jacob, Ph.D. Professor of Neuroscience Sackler School of Graduate Biomedical Sciences Tufts University MedicalResearch: What are the main findings of the study? Dr. Jacob: Autistic-like behaviors and cognitive impairments associate with loss of the Adenomatous Polyposis Coli (APC) gene.  We deleted APC chiefly from excitatory neurons in the mouse developing forebrain; the mice exhibited changes in synapse maturation and density, reduced social interest, increased repetitive behaviors, and learning deficits.  In addition, we found  molecular changes that define a novel role for APC in linking to and regulating the levels of particular proteins that function in synaptic adhesion complexes and signaling pathways that are required for normal learning and memory consolidation. (more…)