B57: Gut Microbes and Atherosclerosis: How Your Microbiome Is Influencing Your Health

Because of its variation across different individuals even in similar environments, the gut microbiome can influence the health of different people in different ways. One major example is the way that different microbes consume quaternary amine compounds (QAs) that are prevalent in the human diet, such as in red meat and wheat. Some gut microbes convert these compounds into trimethylamine (TMA), which is then oxidized by the human liver to form trimethylamine-N-oxide (TMAO). Previously, TMAO was shown to be linked to the development of atherosclerosis, or the buildup of plaque in arteries. However, other gut microbes have been identified that remove methyl groups from QAs, or demethylate them, to yield a different product. Previously, Dr. Ferguson’s laboratory found that a bacterial strain, Desulfitobacterium hafniense Y51, contains enzymes that can demethylate the QA glycine betaine to form dimethylglycine and methane, instead of TMA. By expanding upon the known gut microbes capable of demethylating different QAs, additional enzymes can be identified that may reduce the risk of atherosclerosis in the gut. The first aim of this project was to determine which QAs can be consumed by another strain of D. hafniense in the human gut, the DP7 strain. The next aim was to identify the potential enzymes it may use to consume these QAs, and to reconstruct these enzymatic pathways to verify their function. The DP7 strain was found to grow when given carnitine, another QA, and to have genes that are similar to the demethylation genes of the Y51 strain. Discovering the function of these DP7 genes could reveal a previously unknown metabolic pathway in the human gut. Using these DP7 enzymes as a gut probiotic could reduce the risk of plaque build-up in blood vessels deriving from carnitine in the human diet, leading to a lower incidence of atherosclerosis.

Author: Sarah Soppe

Faculty Advisor: D.J. Ferguson, Department of Microbiology

Graduate Student Advisor: Jyoti Kashyap, Department of Microbiology

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