Xavier, Ramnik

Phone: 617-643-3331


Ramnik Xavier is the Kurt Isselbacher Professor of Medicine at Harvard Medical School and the Chief of Gastroenterology at the Massachusetts General Hospital. He is Board Certified in Medicine and Gastroenterology. Ramnik is also the Director of the Center for the Study of Inflammatory Bowel Disease (CSIBD) and a Senior Associate Member of the Broad Institute of MIT and Harvard. Ramnik is clinically active, teaching medical students, residents in medicine, and gastroenterology fellows rotating through the MGH.

Following his clinical training, he completed a postdoctoral fellowship with Professor Brian Seed in the Department of Molecular Biology at MGH and the Department of Genetics at the Harvard Medical School. The overall goal in the laboratory is to discover and understand the function of important mediators and effectors involved in innate (autophagy, pathogen-containing vacuole) and adaptive (T cell activation) immunity. Of particular interest are the cellular components and regulatory networks, which interact dynamically within temporal, spatial and pathophysiological contexts of innate and adaptive immunity. The lab is pursuing integrative systems approaches that closely couple genome-wide experimentation with high-throughput assays and computational methods.

A second area of focus is to examine the pathway defects associated with genetic variants in IBD/T1D and identify novel small molecules that interrupt signal transduction pathways associated with disease risk.

Selected Publications (from total of 202)


Ananthakrishnan AN, Nguyen DD, Sauk J, Yajnik V, Xavier RJ
Genetic Polymorphisms in Metabolizing Enzymes Modifying the Association Between Smoking and Inflammatory Bowel Diseases.
Inflamm Bowel Dis. 2014;20(5):783-9 - PMID: 24651583
Gevers D, Kugathasan S, Denson LA, Vázquez-Baeza Y, Van Treuren W, Ren B, Schwager E, Knights D, Song SJ, Yassour M, Morgan XC, Kostic AD, Luo C, González A, McDonald D, Haberman Y, Walters T, Baker S, Rosh J, Stephens M, Heyman M, Markowitz J, Baldassano R, Griffiths A, Sylvester F, Mack D, Kim S, Crandall W, Hyams J, Huttenhower C, Knight R, Xavier RJ
The treatment-naive microbiome in new-onset Crohn's disease.
Cell Host Microbe. 2014;15(3):382-92 - PMID: 24629344
Pulloor NK, Nair S, Kostic AD, Bist P, Weaver JD, Riley AM, Tyagi R, Uchil PD, York JD, Snyder SH, García-Sastre A, Potter BV, Lin R, Shears SB, Xavier RJ, Krishnan MN
Human Genome-Wide RNAi Screen Identifies an Essential Role for Inositol Pyrophosphates in Type-I Interferon Response.
PLoS Pathog. 2014;10(2):e1003981 - PMID: 24586175 - PMCID: PMC3937324
de Luca A, Smeekens SP, Casagrande A, Iannitti R, Conway KL, Gresnigt MS, Begun J, Plantinga TS, Joosten LA, van der Meer JW, Chamilos G, Netea MG, Xavier RJ, Dinarello CA, Romani L, van de Veerdonk FL
IL-1 receptor blockade restores autophagy and reduces inflammation in chronic granulomatous disease in mice and in humans.
Proc Natl Acad Sci U S A. 2014;111(9):3526-31 - PMID: 24550444 - PMCID: PMC3948220
Kostic AD, Xavier RJ, Gevers D
The Microbiome in Inflammatory Bowel Diseases: Current Status and the Future Ahead.
Gastroenterology. 2014;146(6):1489-99 - PMID: 24560869
Fowler SA, Ananthakrishnan AN, Gardet A, Stevens CR, Korzenik JR, Sands BE, Daly MJ, Xavier RJ, Yajnik V
SMAD3 gene variant is a risk factor for recurrent surgery in patients with Crohn's disease.
J Crohns Colitis. 2014;:ePub - PMID: 24461721
Ananthakrishnan AN, Huang H, Nguyen DD, Sauk J, Yajnik V, Xavier RJ
Differential Effect of Genetic Burden on Disease Phenotypes in Crohn's Disease and Ulcerative Colitis: Analysis of a North American Cohort.
Am J Gastroenterol. 2014;109(3):395-400 - PMID: 24419484
Lee E, Koo Y, Ng A, Wei Y, Luby-Phelps K, Juraszek A, Xavier RJ, Cleaver O, Levine B, Amatruda JF
Autophagy is essential for cardiac morphogenesis during vertebrate development.
Autophagy. 2014;10(4):572-87 - PMID: 24441423
Liu Y, Shoji-Kawata S, Sumpter RM, Wei Y, Ginet V, Zhang L, Posner B, Tran KA, Green DR, Xavier RJ, Shaw SY, Clarke PG, Puyal J, Levine B
Autosis is a Na+,K+-ATPase-regulated form of cell death triggered by autophagy-inducing peptides, starvation, and hypoxia-ischemia.
Proc Natl Acad Sci U S A. 2013;110(51):20364-71 - PMID: 24277826 - PMCID: PMC3870705
Smeekens SP, Malireddi RK, Plantinga TS, Buffen K, Oosting M, Joosten LA, Kullberg BJ, Perfect JR, Scott WK, van de Veerdonk FL, Xavier RJ, van de Vosse E, Kanneganti TD, Johnson MD, Netea MG
Autophagy is redundant for the host defense against systemic Candida albicans infections.
Eur J Clin Microbiol Infect Dis. 2013;33(5):711-22 - PMID: 24202731
Begun J, Xavier RJ
Autophagy at the crossroads of metabolism and cellular defense.
Curr Opin Gastroenterol. 2013;29(6):588-596 - PMID: 24100719
Kleinnijenhuis J, Quintin J, Preijers F, Benn CS, Joosten LA, Jacobs C, van Loenhout J, Xavier RJ, Aaby P, van der Meer JW, van Crevel R, Netea MG
Long-Lasting Effects of BCG Vaccination on Both Heterologous Th1/Th17 Responses and Innate Trained Immunity.
J Innate Immun. 2013;6(2):152-8 - PMID: 24192057 - PMCID: PMC3944069
Shaw SY, Tran K, Castoreno AB, Peloquin JM, Lassen KG, Khor B, Aldrich LN, Tan PH, Graham DB, Kuballa P, Goel G, Daly MJ, Shamji AF, Schreiber SL, Xavier RJ
Selective Modulation of Autophagy, Innate Immunity, and Adaptive Immunity by Small Molecules.
ACS Chem Biol. 2013;8(12):2724-33 - PMID: 24168452 - PMCID: PMC3951132
Knights D, Lassen KG, Xavier RJ
Advances in inflammatory bowel disease pathogenesis: linking host genetics and the microbiome.
Gut. 2013;62(10):1505-10 - PMID: 24037875 - PMCID: PMC3822528
Vandussen KL, Liu TC, Li D, Towfic F, Modiano N, Winter R, Haritunians T, Taylor KD, Dhall D, Targan SR, Xavier RJ, McGovern DP, Stappenbeck TS
Genetic Variants Synthesize to Produce Paneth Cell Phenotypes that Define Subtypes of Crohn's Disease.
Gastroenterology. 2013;146(1):200-9 - PMID: 24076061 - PMCID: PMC3899786