Endothelial cells exposed to atheroprotective flow secrete follistatin-like protein 1 which reduces transcytosis and inflammation

ABSTRACT: Objective - When endothelium is cultured in wells swirled on an orbital shaker, cells at the well centre experience putatively proatherogenic flow whereas those near the edge experience putatively atheroprotective flow. Transcellular transport is decreased equally in both regions, consistent with it being reduced by a mediator released from cells in one part of the well and mixed in the swirling medium. Here we identify the mediator and the flow characteristics that stimulate its release. Approach and Results - Medium conditioned by cells swirled at the edge, but not by cells swirled at the centre or cultured under static conditions, significantly reduced transendothelial transport of a low density lipoprotein (LDL)-sized tracer. Mass spectrometry identified follistatin-like 1 (FSTL1) as a candidate mediator. Cells from the swirled edge produced more FSTL1 than cells from the swirled centre or from static wells. Exogenous FSTL1 reduced transendothelial transport of the LDL-sized tracer and of LDL itself. An inhibitor of transcytosis similarly inhibited tracer transport. Exogenous FSTL1 and medium conditioned by cells swirled at the well edge also inhibited TNF-α-induced VCAM-1 and ICAM-1 expression, phosphorylation of IκBα, nuclear translocation of NF-κB, and monocyte adhesion. Conclusions - Putatively atheroprotective flow stimulates production of FSTL1 from cultured endothelial cells. FSTL1 reduces transcellular transport of LDL-sized particles and of LDL itself, and inhibits endothelial activation. If this also occurs in vivo, it may account for the atheroprotective nature of such flow. The identification of a mediator linking flow to LDL transport suggests novel therapeutic strategies.

INSTRUMENT(S): Q Exactive HF

ORGANISM(S): Sus Scrofa Domesticus (domestic Pig)

TISSUE(S): Cell Culture, Aortic Endothelial Cell

SUBMITTER: Xiaoke Yin  

LAB HEAD: Manuel Mayr

PROVIDER: PXD022068 | Pride | 2021-08-23

REPOSITORIES: Pride