Silencing of FUN14 Domain Containing 1 Inhibits Platelet Activation in Diabetes Mellitus through Blocking Mitophagy.

Abstract

Platelet hyperactivity represents a deleterious physiological phenomenon in diabetes mellitus (DM). This study aimed to explore the role of FUN14 domain containing 1 (FUNDC1) in platelet activation within the context of DM and to uncover relevant mechanisms, with a focus on mitophagy. A mouse model of DM was established by high-fat feeding and streptozotocin injection. Platelets isolated from whole blood were exposed to carbonyl cyanide-4-(trifluo-romethoxy)phenylhydrazone (FCCP) to induce mitophagy. The relative mRNA expression of FUNDC1 was detected by quantitative real-time PCR (qRT-PCR). Western blotting was employed to measure the protein levels of FUNDC1, the ratio of LC3-II toLC3-I, and cleaved caspase-3. Immunofluorescence and flow cytometry were performed to assess LC3-positive mitochondria and platelet activation factor CD62P, respectively. Additionally, serum levels of β-thrombo-globulin (β-TG) and platelet factor 4 (PF4)were measured by enzyme-linked immunosorbent assay. FUNDC1 expression was elevated in DM mice, and its silencing decreased the body weight and fasting blood glucose. Inhibition of FUNDC1 also significantly attenuated FCCP-induced platelet mitophagy, as evidenced by the down-regulation of the LC3-II/LC3-I ratio, up-regulation of Tomm20, and diminished presence of LC3-positive mitochondria. Moreover, platelet activation was noted in DM mice; this activation was mitigated upon FUNDC1 silencing, which was confirmed by the down-regulation of cleaved caspase-3 and CD62P as well as reductions in β-TG and PF4 serum levels. Silencing of FUNDC1 inhibited platelet hyperactivity in DM by impeding mitophagy. As such, FUNDC1-midiated mitophagy may be a promising target for the treatment of DM and its associated cardiovascular complications related cardiovascular events.