Assembling the anaerobic gamma-butyrobetaine to TMA metabolic pathway in < em > Escherichia fergusonii < /em > and confirming its role in TMA production from dietary < em > L- < /em > carnitine in murine models

mBio. 2023 Sep 22:e0093723. doi: 10.1128/mbio.00937-23. Online ahead of print.ABSTRACTTrimethylamine-N-oxide (TMAO) is a major pro-atherogenic and pro-thrombotic metaorganismal molecule produced through the initial conversion of the dietary L-carnitine and other precursors into trimethylamine (TMA). We recently identified a dual-microbe anaerobic pathway for the metabolism of L-carnitine into TMA, in which the widely distributed cai operon in Enterobacteriaceae converts L-carnitine into gamma-butyrobetaine (γBB), followed by the degradation of γBB into TMA by the relatively rare gamma-butyrobetaine utilization (gbu) gene cluster present in Emergencia timonensis and few other related microbes. Studies of this pathway in animal models, however, have been limited by the lack of single microbes harboring the whole L-carnitine→γBB→TMA transformation pathway. Such recombinant microbes would both serve as a tool to further prove the contribution of this pathway to gut microbial TMA production and for future in vivo studies investigating the diet linkage to cardiovascular disease and the involvement of the TMAO pathway in this linkage. Here, we recapitulate the whole pathway in a single microbe by cloning the E. timonensis gbu gene cluster into Escherichia fergusonii, which naturally harbors the cai operon. We then show that the native E. timonensis GroES/GroEL-like proteins are needed for the proper functioning of the gbu cluster at 37°C. Finally, we demonstrate that inocula...
Source: Atherosclerosis - Category: Cardiology Authors: Source Type: research