Novel MethodsDetection of Protein Aggregation and Proteotoxicity Induced by Angiotensin II in Vascular Smooth Muscle CellsCicalese, Stephanie; Okuno, Keisuke MD, PhD; Eguchi, Satoru MD, PhDAuthor Information Department of Physiology, Cardiovascular Research Center, Lewis Katz School of Medicine, Temple University, Philadelphia, PA. Reprints: Satoru Eguchi, Cardiovascular Research Center, Lewis Katz School of Medicine at Temple University, 3500 N. Broad Street, Philadelphia, PA 19140 (e-mail: [email protected]). Supported by National Institute of Health grant HL133248 (S.E.) The authors report no conflicts of interest. Journal of Cardiovascular Pharmacology: January 2021 - Volume 77 - Issue 1 - p 43-48 doi: 10.1097/FJC.0000000000000934 Buy Metrics Abstract Disruption of protein quality control occurs with aging and cardiovascular pathologies including arterial stiffness and hypertension. Angiotensin II (Ang II) is believed to induce endoplasmic reticulum stress in vascular smooth muscle cells (VSMCs), thus contributing to vascular remodeling and dysfunction. However, whether Ang II increases formation of protein aggregates and mediates proteotoxicity in VSMCs remain obscure. Accordingly, this study aimed to establish a quantitative method of protein aggregate detection induced by Ang II and to investigate their potential involvement in inflammatory and senescence responses. Proteostat staining showed increased aggregate numbers per cell on Ang II exposure. Immunoblot analysis further showed an increase in preamyloid oligomer presence in a detergent insoluble protein fraction purified from VSMCs stimulated with Ang II. Moreover, these responses were attenuated by treatment with chemical chaperone, 4-phenylbutyrate. 4-phenylbutyrate further blocked Ang II-induced senescence associated β-galactosidase activity and THP-1 monocyte adhesion in VSMCs. These data suggest that Ang II induces proteotoxicity in VSMCs which likely contributes to aging and inflammation in the vasculature. Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.