Role of TSP1, TGF-β, and PAI-1 in adipose tissue. TSP1 is expressed by adipose tissue, and activates TGF-β, which in turn activates PAI-1, which is a procoagulant. TGF-β is also activated by high glucose and angiotensin II. TSP1 expression is inhibited by PPARγ agonists, which may explain some of the beneficial effects of these drugs.