Courtesy of Elizabeth Johnson

February 28, 2020

A Gutsy Endeavor: Understanding Metabolites of the Humans’ “Hidden Organ”

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Trillions of microbes inhabit the human digestive system, constituting such a critical part of our health that many researchers have taken to calling the vast, microscopic population the “hidden organ.”

But despite weighing as much as five pounds and collectively containing 200 times the number of genes as the human genome, scientists still aren’t sure how these gut microbes — which include bacteria, fungi and viruses — affect human health.

Answering the call to one of medicine’s perplexing, unresolved questions, Prof. Elizabeth Johnson, nutritional sciences, and her lab are working to study how diet interacts with the human gut microbiome, and, in turn, how our hidden ecosystem of over 100 trillion microbes shapes personal health.

“[There are] potentially thousands of metabolites that we have no idea what [they do] or which microbes produce them, [yet] are having an effect on our health. [This] has gone unrecognized for decades,” Johnson explained.

Her lab’s work centers on the notion of “beneficial microbes,” microorganisms whose existence in humans may actually create a slate of positive effects for their unwitting hosts. While much of medicine is often focused on destroying germs — the goal of Johnson’s research mainly focuses on building closer ties.

For instance, some of her collaborators have identified a molecule, produced by the microbiome, that can not only “have a positive effect on [human] metabolism,” but “actually stop fat accumulation in the liver,” Johnson said.

In a similar vein, the Johnson Lab is trying to characterize a specific group of metabolites called sphingolipids, a class of lipids produced by those “beneficial microbes” that perform a wide range of functions in our bodies, including the production of fat — a process that could potentially have implications on obesity, diabetes and cancer.

According to Johnson, since there are a limited range of usable methods for treating those metabolic disorders, better characterizing the mechanism through which sphingolipids act is a particularly significant pursuit.

“We have a growing need to do [this research] because of the rise of the obesity epidemic, and also the changes in the way we’re eating,” Johnson said.

In other words — while long thought to be disease-bearing marauders — the key to solving one of America’s greatest health crises may lie in calling a truce with bacteria that call our gut home.

Beyond the lab, even though it’s Johnson’s first semester teaching at Cornell, she said she has been lucky to work with a  group of scientists where we’re always trying to think of innovative ways to look at answering the questions that we have.”

“I’m fortunate to be surrounded by a lot of stellar African American scientists on campus,” Johnson continued. “As a faculty member, it’s an exciting time to be here where there are so many great role models to really look up to, and I feel fortunate for that, and I think that really enhanced my time here.”