Identification of SEC61B as a novel regulator of calcium flux and platelet hyperactivity in diabetes mellitus

ABSTRACT: Platelet hyperactivity contributes to increased cardiovascular thrombosis in diabetes. Intracellular and released proteins control platelet activity however there are limited proteomic studies of the diabetic platelet. We isolated platelets from 34 patients without, and 42 patients with type 2 diabetes, matched by age, sex, and coronary artery disease burden. Using high sensitivity unbiased proteomics, we measured over 2,400 intracellular proteins, and detected >70 released proteins only secreted by diabetic platelets indicative of hyperactivation. Importantly, we uniquely identified endoplasmic reticulum (ER) protein SEC61B increased in hyperglycemic human and mouse platelets. SEC61B was increased in megakaryocytes in mouse models of diabetes with evidence of associated ER stress. SEC61 is known to act as a channel for calcium leak, a key aspect in platelet hyperactivation. We demonstrate that cultured cells overexpressing SEC61B had increased cytoplasmic calcium flux and decreased protein synthesis. In accordance, hyperglycemic mouse platelets mobilized more cytoplasmic calcium and had lower protein synthesis compared with normoglycemic platelets. Independent induction of ER stress increased platelet SEC61B expression and P-selectin mobilization. We propose a mechanism whereby ER stress-induced upregulation of platelet SEC61B leads to increased cytoplasmic calcium, potentially contributing to platelet hyperactivity in diabetes.

INSTRUMENT(S): Orbitrap Fusion Lumos

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Blood Platelet, Blood Plasma

SUBMITTER: Mark Larance  

LAB HEAD: Mark Larance

PROVIDER: PXD049321 | Pride | 2025-04-19

REPOSITORIES: Pride