TNFα impairs platelet function by inhibiting autophagy and disrupting metabolism via Syntaxin-17 downregulation.

Platelets play a dual role in hemostasis and inflammation-associated thrombosis and hemorrhage. While the mechanisms linking inflammation to platelet dysfunction remain poorly understood, our previous work demonstrated that TNFα alters mitochondrial mass, platelet activation, and autophagy-related pathways in megakaryocytes. Here, we hypothesized that TNFα impairs platelet function by disrupting autophagy, a process critical for mitochondrial health and cellular metabolism. Using human and murine models of TNFα-driven diseases, including myeloproliferative neoplasms and rheumatoid arthritis, we found that TNFα downregulates STX17, a key mediator of autophagosome-lysosome fusion. This disruption inhibited autophagy, leading to the accumulation of dysfunctional mitochondria and reduced mitochondrial respiration. These metabolic alterations compromised platelet-driven clot contraction, a process linked to thrombotic and hemorrhagic complications. Our findings reveal a mechanism by which TNFα disrupts hemostasis through autophagy inhibition, highlighting TNFα as a critical regulator of platelet metabolism and function. This study provides new insights into inflammation-associated pathologies and suggests autophagy-targeting strategies as potential therapeutic avenues to restore hemostatic balance.