MacArthur Fellows Program

Sarkis Mazmanian

Medical Microbiologist | Class of 2012

Illuminating the complex interplay between microbes and the host immune system and the role certain bacteria may play in the development, or mitigation, of a broad range of human diseases.

Title
Medical Microbiologist
Affiliation
California Institute of Technology
Location
Pasadena, California
Age
39 at time of award

Sarkis Mazmanian is a microbiologist investigating the mechanisms underlying the symbiotic relationship between hosts and their beneficial microbial partners. Non-pathogenic bacteria colonize virtually every tissue type with exposure to the external environment; the enteric bacteria found in the gastrointestinal (GI) tract, which contains by far the largest number and species of bacteria, have long been known to provide benefits such as delivering certain nutrients and protection against pathogenic bacteria. In a series of studies, Mazmanian and colleagues have teased out the complex interplay between gut bacterial species and the host immune system. His results show, for example, that the probiotic species B. fragilis expresses a molecule known as polysaccharide A, which suppresses a specific immune pathway in the host that would otherwise generate an inflammatory response to a different bacterium, H. hepaticus. Absent this suppression, H. hepaticus triggers pathologic changes in the GI tract similar to ulcerative colitis and Crohn’s disease. More recently, Mazmanian found that enteric bacteria can influence the progression of immune activity in distant tissues such as the nervous system. In a mouse model of multiple sclerosis (a human autoimmune disease), he demonstrated that germ-free animals, which are otherwise resistant to induced autoimmune brain inflammation, become susceptible after their GI tract is exposed to segmented filamentous bacteria, suggesting a specific role that intestinal bacterial fauna could play in the development of autoimmune disorders in tissues distant from the intestines (e.g., the central nervous system). On the basis of his results and others’, Mazmanian has posited that harmless bacteria induce host immune tolerance by manipulating pathways that distinguish self from pathogen, a distinction that goes awry in autoimmune diseases. By elucidating the critical role of these microbes in human health, Mazmanian is laying the foundation for a new understanding of human-microbiome symbiosis that could lead to new therapies or preventive treatments for a broad class of human diseases.

Sarkis Mazmanian received a B.S. (1995) and a Ph.D. (2002) from the University of California at Los Angeles. Prior to joining the faculty of the California Institute of Technology in 2006, where he is currently a professor in the Division of Biology, he was affiliated with the University of Chicago (2002–2005) and Harvard Medical School (2005–2006). His scientific articles have appeared in such publications as Science, Nature, PNAS, and Cell.

News About this Fellow
November 10, 2015
"The Hottest New Cancer Drugs Depend on Gut Microbes"
The Atlantic
Sarkis Mazmanian, 2012 MacArthur Fellow
October 30, 2015
"Microbiologist and MacArthur ‘Genius’ Fellow Sarkis Mazmanian to deliver 16th Fred Fay lecture"
University of Massachusetts Medical School
Sarkis Mazmanian, 2012 MacArthur Fellow
August 6, 2015
"Meet Sarkis Mazmanian and the Bacteria That Keep Us Healthy"
Biomedical Beat
Sarkis Mazmanian, 2012 MacArthur Fellow
February 17, 2015
"Mental Health May Depend on Creatures in the Gut"
Scientific American
Sarkis Mazmanian, 2012 MacArthur Fellow
January 8, 2015
"Can Microbes in the Gut Influence the Brain?"
LiveScience
Sarkis Mazmanian, 2012 MacArthur Fellow
November 12, 2014
"Gut–Brain Link Grabs Neuroscientists"
Nature
Sarkis Mazmanian, 2012 MacArthur Fellow
September 8, 2013
"Study Explains Stability of Our Ecosystem Within"
U-T San Diego
Sarkis Mazmanian, 2012 MacArthur Fellow
May 29, 2013
"Probing the Mysteries of Probiotics"
From CNN
Sarkis Mazmanian, MacArthur Fellow, 2012
View all news

Photos

Photos are owned by the MacArthur Foundation and licensed under a Creative Commons license: CC-BY.
Credit: John D. & Catherine T. MacArthur Foundation.

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