Caltech Biologist Sarkis Mazmanian Named MacArthur Fellow

PASADENA, Calif. — Sarkis Mazmanian, a microbiology expert at the California Institute of Technology (Caltech) whose studies of human gut bacteria have revealed new insights into how these microbes can be beneficial, was named a MacArthur Fellow and awarded a five-year, $500,000 grant. Each year, the John D. and Catherine T. MacArthur Foundation awards the unrestricted fellowships — also known as “genius” grants — to individuals who have shown “extraordinary originality and dedication in their creative pursuits and a marked capacity for self-direction,” according to the foundation’s website.

“I was in a state of shock when I heard the news,” said Mazmanian, a professor of biology at Caltech, who was tricked into taking the award announcement call; he thought he was simply being added to a prescheduled conference call. “It’s not the kind of thing you ever expect — I do what I do because I love science and it makes me happy, so this is terrific and a nice reward. At the same time, I never think of awards as goals of mine because they seem so unattainable. My goals are to make discoveries, so I was just in absolute disbelief.”

Long before he was named a 2012 MacArthur Fellow, Mazmanian was showing the attributes that the foundation seeks to reward, particularly a capacity for self-direction. As a graduate student in the early 2000s, he decided to stray from the normal path of study and try something new.

“I had been studying microbial pathogenesis — or bacteria that make us sick — which is what 99.9 percent of the field of microbiology does to this day,” said Mazmanian. “Toward the end of my PhD, I decided that I wanted to study organisms that didn’t necessarily cause disease, but were associated with our bodies. Ten years ago, this was completely on the fringe of science — we knew that the organisms existed in our intestines and all over our bodies, but had no idea what they were doing.”

Today, Mazmanian’s work examines some of the trillions of bacteria living in human bodies that make up complex communities of microbes and regulate

processes like digestion and immunity. His main focus is to understand how “good” bacteria promote human health — work that has transformed a quickly-evolving field of research that is investigating the connection between gut bacteria and their relationship to both disease and health.

His research helped lay the groundwork for the Human Microbiome Project (HMP), an initiative of the National Institutes of Health that aims to characterize, for the first time, “the microbial communities found at several different sites on the human body, including nasal passages, oral cavities, skin, gastrointestinal tract and urogenital tract, and to analyze the role of these microbes in human health and disease,” according to the HMP website. His laboratory was the first to demonstrate that specific gut bacteria direct the development of the mammalian immune system and provide protection from intestinal diseases. This means, he said, that fundamental aspects of health are absolutely dependent on microbial interaction within our bodies. In addition, he said that many disorders whose incidences are increasing in Western countries — such as inflammatory bowel disease, multiple sclerosis and asthma — involve a common immunologic defect believed to be caused by the absence of intestinal bacteria. An understanding of the beneficial immune responses promoted by gut bacteria may lead to the development of natural therapeutics for immunologic and perhaps neurologic diseases, said Mazmanian.

“This award is extremely well-deserved — Sarkis has revolutionized the way we think about the interactions between microorganisms and people,” said Stephen L. Mayo, William K. Bowes Jr. Foundation Chair of Caltech’s Division of Biology, and Bren Professor of

Biology and Chemistry. “His research has had an important impact in making the connection between personal hygiene and the immune system, and even neurological diseases like autism.”

When the award announcement went public, Mazmanian was in Armenia, his native homeland, teaching a one-week course on host-microbial interaction to PhD students at a molecular biology institute. He travels to the country once a year to volunteer his services. The timing, he said, couldn’t be better, as he hopes to use some of the prize money to develop an international educational outreach program.

“I think that when you have a windfall like this, the least you can do is help people who are in need,” said Mazmanian, who credits the members of his lab for his research success. “In many countries, they are in need of education and resources, like lab equipment, text books, you name it. It would be terrific if I could use the money to help advance science in countries where there is hardship.”

Mazmanian received his bachelor’s degree in 1995 and his PhD in microbiology in 2002, both from UCLA. Following a postdoctoral fellowship at Harvard, he joined the Caltech faculty as an assistant professor in 2006. In 2012, he was promoted to professor of biology. In 2011, Mazmanian was the recipient of a Burroughs Welcome Fund Award for research in the pathogenesis of infectious disease, and in 2008 he was awarded a Searle Scholarship and was named one of Discover magazine’s “20 Best Brains Under 40,” which highlighted young innovators in science.

This year’s crop of 23 Fellows includes stringed-instrument bow maker Benoit Rolland and mathematician Maria Chudnovsky; Mazmanian joins the ranks of Caltech’s previous MacArthur Fellows, including 2010 awardee John Dabiri.