title: Intermedin1-53 attenuates vascular smooth muscle cell calcification by inhibiting endoplasmic reticulum stress via cyclic adenosine monophosphate/protein kinase A pathway.
abstract: We previously reported that endoplasmic reticulum (ER) stress-mediated apoptosis participated in vascular calcification. Importantly, a novel paracrine/autocrine peptide intermedin1-53 (IMD1-53) in the vasculature inhibited vascular calcification in rats. But the mechanisms needed to be fully elucidated. Vascular smooth muscle cells (VSMCs) calcification was induced by CaCl2 and β-glycerophosphate. Tunicamycin (Tm) or dithiothreitol (DTT) was used to induce ER stress. We found that IMD1-53 (10(-7)mol/L) treatment significantly alleviated the protein expression of ER stress hallmarks activating transcription factor 4 (ATF4), ATF6, glucose-regulated protein 78 (GRP78) and GRP94 induced by Tm or DTT. ER stress occurred in early and late calcification of VSMCs but was inhibited by IMD1-53. These inhibitory effects of IMD1-53 were abolished by treatment with the protein kinase A (PKA) inhibitor H89. Pretreatment with IMD1-53 decreased the number of apoptotic VSMCs and downregulated protein expression of cleaved caspase 12 and C/EBP homologous protein (CHOP) in calcified VSMCs. Concurrently, IMD1-53 restored the loss of VSMC lineage markers and ameliorated calcium deposition and alkaline phosphatase activity in calcified VSMCs as well. The observation was further verified by Alizarin Red S staining, which showed that IMD1-53 reduced positive red nodules among calcified VSMCs. In conclusion, IMD1-53 attenuated VSMC calcification by inhibiting ER stress through cAMP/PKA signalling.
authors.affiliation: Department of Physiology and Pathophysiology, School of Basic Medical Science, Peking University Health Science Center, Beijing 100191, China.
authors.forename: Jin-Rui
authors.initials: JR
authors.lastname: Chang
authors.forename: Xiao-Hui
authors.initials: XH
authors.lastname: Duan
authors.forename: Bao-Hong
authors.initials: BH
authors.lastname: Zhang
authors.forename: Xu
authors.initials: X
authors.lastname: Teng
authors.forename: Ye-Bo
authors.initials: YB
authors.lastname: Zhou
authors.forename: Yue
authors.initials: Y
authors.lastname: Liu
authors.forename: Yan-Rong
authors.initials: YR
authors.lastname: Yu
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhu
authors.forename: Chao-Shu
authors.initials: CS
authors.lastname: Tang
authors.forename: Yong-Fen
authors.initials: YF
authors.lastname: Qi
mesh_terms: D053607:Adrenomedullin / Q000378:metabolism*; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D002114:Calcinosis / Q000503:physiopathology*; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000378:metabolism*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D059865:Endoplasmic Reticulum Stress / Q000187:drug effects*; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000503:physiopathology; D009479:Neuropeptides / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction; D061205:Vascular Calcification / Q000503:physiopathology*
chemical_list: C499411:Adm2 protein, rat; D009479:Neuropeptides; D053607:Adrenomedullin; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases
keywords: apoptosis; endoplasmic reticulum stress; intermedin1–53; vascular calcification