Mycobacterium tuberculosis encodes a YhhN family membrane protein with lysoplasmalogenase activity that protects against toxic effects of lysolipids

ABSTRACT: Mycobacterium tuberculosis (M.tb) resides in human macrophages where it exploits host lipids for survival. Little is known about the interaction between M.tb and macrophage plasmalogens, the subclass of glycerophospholipids having a vinyl-ether bond at sn-1. Lysoplasmalogens, produced from plasmalogens by hydrolysis at sn-2 by PLA2, are potentially toxic, but can be broken down by host lysoplasmalogenase, an integral membrane protein of the YhhN family that hydrolyzes the vinyl ether bond at sn-1 to release a fatty aldehyde and glycerophospho-ethanolamine or –choline. Curiously, M.tb encodes its own YhhN protein (MtbYhhN) despite having no endogenous plasmalogens. Here, the gene for MtbYhhN (Rv1401) was cloned and expressed in Mycobacterium smegmatis (M.smeg), and the partially purified protein exhibited abundant lysoplasmalogenase activity that was specific for lysoplasmenylethanolamine (pLPE) or lysoplasmenylcholine (pLPC) (Vmax~15.5 mol/min/mg; Km~83 M). Based on monitoring cell density by OD600, pLPE, pLPC, lysophosphatidylcholine (LPC) and lysophosphatidylethanolamine (LPE) were not toxic to intact M.smeg cells, but pLPC and LPC were highly toxic to M.smeg spheroplasts, which are cell wall deficient (CWD) forms that lack the bacterial wall. Importantly, spheroplasts prepared from M.smeg cells overexpressing MtbYhhN were protected from membrane disruption/lysis by pLPC (but not by LPC), which was rapidly depleted from the media. Finally, overexpression of full-length MtbYhhN in M.smeg increased its survival within human macrophages by 2.6-fold compared to vector control at 24 h. These data provide support for the hypothesis that MtbYhhN protein confers a mycobacterial growth advantage in macrophages by cleaving toxic pLPC from the host cells into potentially energy-producing products.

INSTRUMENT(S): LTQ Orbitrap Elite

ORGANISM(S): Mycobacterium Tuberculosis

DISEASE(S): Tuberculosis

SUBMITTER: TuKiet Lam  

LAB HEAD: TuKiet Lam

PROVIDER: PXD027875 | Pride | 2022-05-20

REPOSITORIES: Pride