Silencing of FUN14 domain containing 1 inhibits platelet activation in diabetes mellitus through blocking mitophagy

Objectives: Platelet hyperactivity is an adverse physiological event in diabetes mellitus (DM). This study aimed to explore the function of FUN14 domain containing 1 (FUNDC1) on the platelet activation in DM and reveal relevant mechanisms involving mitophagy. Methods: A mouse model of DM was established by high fat feeding and streptozotocin injection. Platelets that separated from whole blood were incubated with FCCP to induce mitophagy. Relative mRNA expression of FUNDC1 was detected by qRT-PCR. The protein expression of FUNDC1, LC3-II/LC3-I, FUNDC1 (two mitophagy marker), and cleaved caspase-3 (a pro-apoptotic factor) were measured by western blot. Immunofluorescence and flow cytometry were performed to detect LC3-positive mitochondria and CD62P (a platelet activating factor), respectively. Besides, the serum levels of β-TG and PF4 (two platelet specific proteins) were measured by enzyme linked immunosorbent assay. Results: FUNDC1 is up-regulated in DM mice, and its silencing decreased the body weight and fasting blood glucose. Silencing of FUNDC1 also significantly weakened the effects of FCCP on inducing platelet mitophagy, evidenced by the down-regulation of LC3-II/LC3-I, up-regulation of Tomm20, and a decrease in LC3-positive mitochondria. In addition, the platelets were activated in DM mice. Silencing of FUNDC1 weakened platelet hyperactivity in DM, evidenced by the down-regulation of cleaved caspase-3 and CD62P, and the decrease in β-TG and PF4 levels. Conclusions: Silencing of FUNDC1 inhibits platelet hyperactivity in DM through blocking mitophagy. FUNDC1-midiated mitophagy may be a promising target for the treatment of DM and related cardiovascul