Microbiome-derived carnitine mimics as previously unknown mediators of gut-brain axis communication

Citation

Hulme H, Meikle LM, Strittmatter N, van der Hooft JJJ, Swales J, Bragg RA, Villar VH, Ormsby MJ, Barnes S, Brown SL, Dexter A, Kamat MT, Komen JC, Walker D & Milling S (2020) Microbiome-derived carnitine mimics as previously unknown mediators of gut-brain axis communication. Science Advances, 6 (11), Art. No.: eaax6328. https://doi.org/10.1126/SCIADV.AAX6328

Abstract
Alterations to the gut microbiome are associated with various neurological diseases, yet evidence of causality and identity of microbiome-derived compounds that mediate gut-brain axis interaction remain elusive. Here, we identify two previously unknown bacterial metabolites 3-methyl-4-(trimethylammonio)butanoate and 4-(trimethylammonio)pentanoate, structural analogs of carnitine that are present in both gut and brain of specific pathogen-free mice but absent in germ-free mice. We demonstrate that these compounds are produced by anaerobic commensal bacteria from the family Lachnospiraceae (Clostridiales) family, colocalize with carnitine in brain white matter, and inhibit carnitine-mediated fatty acid oxidation in a murine cell culture model of central nervous system white matter. This is the first description of direct molecular inter-kingdom exchange between gut prokaryotes and mammalian brain cells, leading to inhibition of brain cell function.

Notes
Additional co-authors: Emily K. Osterweil, Andrew S. MacDonald, Chris J. Schofield, Saverio Tardito, Josephine Bunch, Gillian Douce, Julia M. Edgar, RuAngelie Edrada-Ebel, Richard J. A. Goodwin, Richard Burchmore, Daniel M. Wall

Journal
Science Advances: Volume 6, Issue 11

• Published version