He has made significant contributions to the field of pharmacogenomics including the identification of a gene that is involved in cardiomyopathy and congestive heart failure after cancer treatment (Aminkeng F et al, Nature Genetics. 2015 Sep; 47(9):1079-84.). He is the recipient of a number of fellowships including the Canadian Institutes of Health Research, Michael Smith Foundation for Health Research and the British Columbia Children Hospital Research Institute Bertram Hoffmeister Postdoctoral Fellowships. He has also been recognized for a distinguish academic and scientific career through a number of career awards including the Canadian Society of Pharmacology and Therapeutics Boehringer Ingelheim Postdoctoral Award in Pharmacology, the British Columbia Children Hospital Research Institute award for outstanding achievement by a postdoctoral fellow, the Golden Helix Top Prize and the Canadian Society of Pharmacology and Therapeutics Publication Award. He currently serves on the Editorial Board of the Journal of Population Therapeutics and Clinical Pharmacology and is a member of the Canadian Society of Pharmacology and Therapeutics Scientific Program Committee.
Instructor in Medicine, Harvard Medical School
Associate Physician, Brigham and Women's Hospital
The primary focus of Dr Tantisira's research efforts, have been in the pharmacogenetics of asthma therapeutics. With a focus on the pharmacogenetics of the beta-agonist and corticosteroid pathways and have made significant progress, they have identified genes that influence bronchodilator response in asthmatics, corticosteroid response over time as manifested by changes in FEV1, differences in airways hyperresponsiveness in patients on corticosteroids, and prediction of who will be hospitalized while on inhaled steroids
I have pursued research in pharmacogenomics over the past twenty years, first with a focus on molecular genetics of target genes, and then increasingly broadening into a genomics approach, including chemogenomics and systems biology. My research focuses on genetic variability in drug response and disease risk. We study regulatory polymorphisms that affect gene expression, RNA processing, and translation, playing a main role in inter-individual differences in disease and therapy. Since 2002 at OSU College of Medicine, I have developed a Center for Pharmacogenomics, tying together multiple research groups at OSU and beyond. Previously support by an NIH GMS U01 project “Regulatory variants in Drug Therapy”, under the umbrella of the Pharmacogenomics Research Network, has fostered functional genomics core laboratory with next-gen sequencing, collaborations in bioinformatics, mathematical modeling, and clinical sciences. I anticipate that genomic medicine and in particular pharmacogenomics is at the cusp of taking a quantum leap towards clinical implementation, because the tools available to us have expanded dramatically. More recently through a growing collaboration with Dr. Schlesinger and the Center of Microbial Interface Biology, my group has developed an extensive research program to understand the genomics of M.tb infection of human macrophages, with focus on the innate immune system – containing numerous genes under strong evolutionary selection and targets of numerous drugs, in a broad spectrum of disorders. A further personal goal is to translate our results into robust biomarker panels predictive of drug response, with much potential to advance personalized therapeutics, and thereby, improve therapy of complex disorders with tangible benefits to society.
Understanding each gene locus or gene cluster as an integrated regulatory: exampleCHRNA5-CHRNA3- CHRNB4 nicotinic receptor gene cluster
Approach. We have develop an R package (K. Hartman) to canvass multiple databases including GTEx, dbGaP, ENCODE, 1,000 genomes project, etc, to extract LD, eQTLs, GWAS hits, and chromatin annotations, applicable to hundreds of genes at a time. This was applied to the nicotinic gene cluster to determine the main LD blocks and candidate variants associated with expression in body tissues and GWAS hits (3).
Results. In a first step, we have identified the main haplotype blocks and three SNPs, the regulatory variants rs880395 and rs1948, plus the known nonsynonymous CHRNA5 rs16969968, a known risk variant in nicotine dependence. Importantly, rs880395 affects the RNA expression of CHRNA3 and 5, and of an antisense RNA, while rs1948 affects specifically CHRNA3 only in the basal ganglia – a region important to nicotine dependence. The predominant LD structure in the gene cluster enables assignment of haplotypes and diplotypes with high confidence in a majority a study cohort. These results document the interactive nature of variants in this gene locus, modified in a tissue specific manner critical for determining influence on specific target traits.
Analysis of a GWAS cohort with nicotine dependence confirmed the known influence of the nsSNP alone, but haplotype and diplotype analyses reveal significant modulation of the influence of rs16969968 on nicotine dependence.
Conclusion. The CHRNA5-CHRNA3-CHRNB4 nicotinic receptor gene cluster represents a local regulome that should be considered for its overall influence on complex traits such as nicotine dependence. Operating via DNA looping over long distances, each regulatory variant can modify expression of multiple genes in an interactive fashion. We are now systematically expanding our approach to multiple gene loci and gene clusters, including cardiovascular and CNS disorder gene candidates, and genes in the innate immune system, which is under strong evolutionary constraints.
- Intronic polymorphism in CYP3A4 affects hepatic expression and response to statin drugs. D. Wang, Y. Guo, S.A. Wrighton, G.E. Cooke, W. Sadee. Pharmacogenomics J 11: 274-286 (2011). PMID 20386561
- D. Wang, M.J. Poi, X. Sun, A. Gaedigk, J.S. Leeder, W. Sadee. Common CYP2D6 Polymorphisms Affecting Alternative Splicing and Transcription: Long-range Haplotypes with Two Regulatory Variants Modulate CYP2D6 Activity. Hum.Mol.Gen. 23: 268-278 (2014). PMID:23985325.
- E.S. Barrie, K. Hartmann, S.-H. Lee, J.T. Frater, M. Seweryn, D. Wang, W. Sadee. The CHRNA5/CHRNA3/CHRNB4 nicotinic receptor regulome: genomic architecture, regulatory variants, and clinical associations. Human Mutation, in print (2016). PMID:27758088, doi: 10.1002/humu.23135. https://www.ncbi.nlm.nih.gov/pubmed/27758088
Chair, Department of Biomedical and Translational Informatics
Chief Research Informatics Officer
Geisinger Health System
Dr. Marylyn Ritchie, PhD is a Professor and Chair in the Department of Biomedical and Translational Informatics at Geisinger Health System. Dr. Ritchie is a statistical and computational geneticist with a focus on understanding genetic architecture of complex human disease. She has expertise in developing novel bioinformatics tools for complex analysis of big data in genetics, genomics, and clinical databases, in particular in the area of Pharmacogenomics. Dr. Ritchie has received several awards and honors including selection as a Genome Technology Rising Young Investigator in 2006, an Alfred P. Sloan Research Fellow in 2010, a KAVLI Frontiers of Science fellow by the National Academy of Science from 2011-2014, and she was named one of the most highly cited researchers in her field by Thomas Reuters in 2014. Dr. Ritchie has extensive experience in all aspects of genetic epidemiology and translational bioinformatics as it relates to human genomics. She also has extensive expertise in dealing with big data and complex analysis including GWAS, next-generation sequencing, CNVs, data integration of meta-dimensional omics data, Phenome-wide Association Studies (PheWAS), and development of data visualization approaches.
PGRN Hub & the Featured Investigator