Pluto Bioinformatics

GSE71699: Marginal zone B cells control follicular helper T cell response to high cholesterol diet

Bulk RNA sequencing

Splenic innate-like marginal zone B (MZB) cells are strategically positioned at the interface between the circulating blood and lymphoid tissue, where they initiate rapid immune responses to blood-borne antigens. Here, we find that selective genetic deletion of MZB cells substantially increases the follicular helper T (Tfh) cell and germinal center (GC) response to high cholesterol diet (HCD), which leads to T cell-dependent acceleration of atherosclerosis. We show that MZB cells activate a homeostatic program in response to HCD, in which upregulation of the transcription factor Atf3 plays a determinant regulatory role. Shuttling of MZB cells to the follicle is dispensable for their regulatory properties on Tfh cells. Instead, HCD promotes increased interaction between MZB and (pre-)Tfh cells outside the follicle, and upregulates MZB cell expression of Cd274 in an Atf3-dependent manner. Interaction between MZB and Tfh cells leads to Cd274-mediated suppression of Tfh cell motility, limits Tfh cell accumulation in the follicle and suppresses the pro-atherogenic Tfh/GC response. Our findings reveal a previously unsuspected role for MZB cells in the control of Tfh/GC response to a cholesterol diet, and uncover a new mechanism through which MZB cells can couple their unique metabolic and innate immune properties and use them to maintain a tolerogenic state. The results may have broad (patho)physiological implications. SOURCE: Brian,Yee Hong,Lam (yhbl2@cam.ac.uk) - University of Cambridge