Malin, S. G. | bioRxiv Science

bioRxiv2021

Identification and Characterization of Human Activation-Induced ChAT+CD4+ T Cells

Vasodilation is a cornerstone of inflammation physiology. By regulating vasodilation and tissue entry of T cells, CD4+ T lymphocytes expressing choline acetyltransferase (ChAT), a key enzyme for biosynthesis of the vasorelaxant acetylcholine (ACh), critically link immunity with vascular biology in mice. However, the characterization of primary human ChAT+ T cells remained elusive. Here, we identified human ChAT+ T cells and report that ChAT mRNA was induced by activation. Functional studies demonstrated that T cell-derived ACh increased muscarinic ACh-receptor dependent NO-synthase activity and vasorelaxation. Further, single-cell RNA-sequencing revealed ChAT+CD4+ T cells in blood from patients with severe circulatory failure and a high relative frequency of ChAT+CD4+ T cells correlated with better 30-day survival in this cohort. Our findings provide the first insights into ChAT biology in primary human T cells, linking ChAT+ T cells with vasorelaxation as well as survival in a cohort of critically ill patients.

immunology↗

bioRxiv2020

Alternate models of acute dyslipidemia reveal divergent pathways upon atherosclerosis initiation

Atherosclerosis is thought to be initiated by the sub-intimal retention of apolipoprotein-B containing lipoproteins within susceptible sites of the vasculature. Understanding this initiation is not possible with current legacy mouse models of atherosclerosis. We created two mouse strains of inducible hypercholesterolemia based on conditional loss of apolipoprotein E or through inducible expression of a gain-of-function proprotein convertase subtilisin/kexin type 9 D374Y mutation. Both strains rapidly broke plasma-lipid homeostasis and converted to a state of atherogenic dyslipidemia, resulting in overt aortic-accumulation of lipoproteins within 10 days. RNA-sequencing revealed that the vascular response is completely dependent on the route taken to dyslipidemia, which nevertheless implicates known pathogenic pathways in the aetiology of atherosclerosis, and further implicates APOE as an inhibitor of inflammation. As atherosclerosis develops, a convergence of common mechanistic processes emerge in both strains with significant involvement of the immune system, and targeting of CD8 T cells can regulate a conserved aortic response. Our results define atherosclerosis initiation as highly heterogeneous process and identify multiple potential therapeutic targets that may influence disease onset.

physiology↗