Abstract
Clinical and epidemiological studies support a connection between obesity and thrombosis, involving elevated expression of the prothrombotic molecules plasminogen activator inhibitor-1 and tissue factor (TF) and increased platelet activation. Cardiovascular diseases and metabolic syndrome–associated disorders, including obesity, insulin resistance, type 2 diabetes, and hepatic steatosis, involve inflammation elicited by infiltration and activation of immune cells, particularly macrophages, into adipose tissue. Although TF has been clearly linked to a procoagulant state in obesity, emerging genetic and pharmacologic evidence indicate that TF signaling via G protein-coupled protease-activated receptors (PAR2, PAR1) additionally drives multiple aspects of the metabolic syndrome. TF–PAR2 signaling in adipocytes contributes to diet-induced obesity by decreasing metabolism and energy expenditure, whereas TF–PAR2 signaling in hematopoietic and myeloid cells drives adipose tissue inflammation, hepatic steatosis, and insulin resistance. TF-initiated coagulation leading to thrombin–PAR1 signaling also contributes to diet-induced hepatic steatosis and inflammation in certain models. Thus, in obese patients, clinical markers of a prothrombotic state may indicate a risk for the development of complications of the metabolic syndrome. Furthermore, TF-induced signaling could provide new therapeutic targets for drug development at the intersection between obesity, inflammation, and thrombosis.
Central role of suppressors of cytokine signaling proteins in hepatic steatosis, insulin resistance, and the metabolic syndrome in the mouse
