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 214)


Sundberg TB, Xavier RJ, Schreiber SL, Shamji AF
Small-molecule control of cytokine function: new opportunities for treating immune disorders.
Curr Opin Chem Biol. 2014;23C:23-30 - PMID: 25222143
Kumar V, Cheng SC, Johnson MD, Smeekens SP, Wojtowicz A, Giamarellos-Bourboulis E, Karjalainen J, Franke L, Withoff S, Plantinga TS, van de Veerdonk FL, van der Meer JW, Joosten LA, Sokol H, Bauer H, Herrmann BG, Bochud PY, Marchetti O, Perfect JR, Xavier RJ, Kullberg BJ, Wijmenga C, Netea MG
Immunochip SNP array identifies novel genetic variants conferring susceptibility to candidaemia.
Nat Commun. 2014;5:4675 - PMID: 25197941
Doench JG, Hartenian E, Graham DB, Tothova Z, Hegde M, Smith I, Sullender M, Ebert BL, Xavier RJ, Root DE
Rational design of highly active sgRNAs for CRISPR-Cas9-mediated gene inactivation.
Nat Biotechnol. 2014;:ePub - PMID: 25184501
Goel G, Conway KL, Jaeger M, Netea MG, Xavier RJ
Multivariate inference of pathway activity in host immunity and response to therapeutics.
Nucleic Acids Res. 2014;42(16):10288-306 - PMID: 25147207
Lassen KG, Xavier RJ
An alteration in ATG16L1 stability in Crohn disease.
Autophagy. 2014;10(10):1858-1860 - PMID: 25136803
Sundberg TB, Choi HG, Song JH, Russell CN, Hussain MM, Graham DB, Khor B, Gagnon J, O'Connell DJ, Narayan K, Dan?ík V, Perez JR, Reinecker HC, Gray NS, Schreiber SL, Xavier RJ, Shamji AF
Small-molecule screening identifies inhibition of salt-inducible kinases as a therapeutic strategy to enhance immunoregulatory functions of dendritic cells.
Proc Natl Acad Sci U S A. 2014;111(34):12468-12473 - PMID: 25114223 - PMCID: PMC4151730
Haberman Y, Tickle TL, Dexheimer PJ, Kim MO, Tang D, Karns R, Baldassano RN, Noe JD, Rosh J, Markowitz J, Heyman MB, Griffiths AM, Crandall WV, Mack DR, Baker SS, Huttenhower C, Keljo DJ, Hyams JS, Kugathasan S, Walters TD, Aronow B, Xavier RJ, Gevers D, Denson LA
Pediatric Crohn disease patients exhibit specific ileal transcriptome and microbiome signature.
J Clin Invest. 2014;124(8):3617-33 - PMID: 25003194 - PMCID: PMC4109533
Wei SC, Tan YY, Weng MT, Lai LC, Hsiao JH, Chuang EY, Shun CT, Wu DC, Kao AW, Chuang CS, Ni YH, Shieh MJ, Tung CC, Chen Y, Wang CY, Xavier RJ, Podolsky DK, Wong JM
SLCO3A1, a Novel Crohn's Disease-Associated Gene, Regulates NF-?B Activity and Associates with Intestinal Perforation.
PLoS One. 2014;9(6):e100515 - PMID: 24945726 - PMCID: PMC4063938
Tam JM, Mansour MK, Khan NS, Seward M, Puranam S, Tanne A, Sokolovska A, Becker CE, Acharya M, Baird MA, Choi AM, Davidson MW, Segal BH, Lacy-Hulbert A, Stuart LM, Xavier RJ, Vyas JM
Dectin-1 dependent LC3 recruitment to phagosomes enhances fungicidal activity in macrophages.
J Infect Dis. 2014;:ePub - PMID: 24842831
Lassen KG, Kuballa P, Conway KL, Patel KK, Becker CE, Peloquin JM, Villablanca EJ, Norman JM, Liu TC, Heath RJ, Becker ML, Fagbami L, Horn H, Mercer J, Yilmaz OH, Jaffe JD, Shamji AF, Bhan AK, Carr SA, Daly MJ, Virgin HW, Schreiber SL, Stappenbeck TS, Xavier RJ
Atg16L1 T300A variant decreases selective autophagy resulting in altered cytokine signaling and decreased antibacterial defense.
Proc Natl Acad Sci U S A. 2014;111(21):7741-7746 - PMID: 24821797 - PMCID: PMC4040621
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 - PMCID: PMC4113010
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 - PMCID: PMC4059512
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


Huttenhower C, Kostic AD, Xavier RJ
Inflammatory Bowel Disease as a Model for Translating the Microbiome.
Immunity. 2014;40(6):843-854 - PMID: 24950204 - PMCID: PMC4135443