Background
Type 2 diabetes mellitus (T2DM) presents a thrombotic environment, contributing to diabetic macroangiopathy and microangiopathy. In this study, the regulation of microthrombosis in T2DM was assessed.
Conclusion
In platelets, macroautophagy promotes protein digestion, subsequently facilitating platelet activation, ANGII-mediated vasoconstriction, and microthrombosis. Our results suggested that lysosome is a promising therapeutic target for antithrombotic treatment in T2DM.
Methods
Platelets from T2DM patients and healthy controls were analyzed using 4D label-free proteomics and bioinformatics. The role of autophagy in T2DM platelet activation and conversion of platelet-derived angiotensinogen (AGT) was investigated.
Results
The results showed that complement and coagulation cascades, platelet activation, metabolic pathways, endocytosis, autophagy, and other protein digestion-related pathways were enriched. The levels of the key protein AGT were increased in T2DM platelets. Chloroquine (CQ) inhibited ADP- or arachidonic acid (AA)-stimulated platelet aggregation and granule release in a dose-dependent manner, while the effects were less pronounced or even reversed for the proteasome inhibitor PYR-41 and the endocytosis inhibitor Pitstop 2. This indicated the dependence of platelet activation and the accompanying protein digestion on the autophagy-lysosome pathway. Mitophagy occurred in fresh T2DM platelets and ADP- or storage-stimulated platelets; mitophagy was inhibited by CQ. However, the mitophagy inhibitor Mdivi-1 failed to show effects similar to those of CQ. AGT, which could be transformed into ANGII in vitro by ADP-stimulated platelets, was upregulated in T2DM platelets and in MEG-01 cell-derived platelets cultured in a high-glucose medium. Finally, microthrombosis was alleviated as indicated by a reduction in the levels of red blood cells in the liver, spleen, heart, and kidney tissues of db/db mice treated with CQ or valsartan.