Endoplasmic reticulum protein 5 (ERp5) attenuates platelet endoplasmic reticulum stress and secretion in a mouse model
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ABSTRACT: Extracellular protein disulphide isomerases (PDIs) are required for in vivo thrombus formation in mice. Platelets secrete ~10% of their PDIs upon activation, including PDI, endoplasmic reticulum protein 57 (ERp57), ERp72, ERp46 and ERp5, which promote platelet aggregation. However the role of intracellular PDIs in platelet function is unknown. In the current study, we aimed to characterize the role of ERp5 (gene Pdia6) using platelet conditional knockout mice (Pf4Cre+/ERp5fl/fl). Pf4Cre+/ERp5fl/fl mice developed mild macrothrombocytopenia. Platelets deficient in ERp5 showed a marked increase in constitutive ER stress as indicated by a 2-fold upregulation of ER proteins including PDI, ERp57, ERp72, ERp46, GRP78, calreticulin and the phosphorylation of IRE-1 and eIF2a. The activation of platelet ER stress pathways in Pf4Cre+/ERp5fl/fl mice was associated with increased protein secretion, Ca2+ mobilization and thrombus formation in a carotid injury model. Our results support that ERp5 acts as negative regulator of ER stress response in platelets, and highlight the differential action of intracellular versus extracellular ERp5. The results also indicate a previously unanticipated role of platelet ER stress in platelet secretion. This may have important implications for therapeutic applications of ER stress inhibitors in thrombosis.
INSTRUMENT(S): Q Exactive HF
ORGANISM(S): Mus Musculus (mouse)
TISSUE(S): Blood Platelet
SUBMITTER: Mark Larance
LAB HEAD: Dr Mark Larance
PROVIDER: PXD034094 | Pride | 2022-12-13
REPOSITORIES: Pride
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