PMID- 36386326 OWN - NLM STAT- PubMed-not-MEDLINE LR - 20221118 IS - 2297-055X (Print) IS - 2297-055X (Electronic) IS - 2297-055X (Linking) VI - 9 DP - 2022 TI - Interactive contribution of hyperinsulinemia, hyperglycemia, and mammalian target of rapamycin signaling to valvular interstitial cell differentiation and matrix remodeling. PG - 942430 LID - 10.3389/fcvm.2022.942430 [doi] LID - 942430 AB - Diabetes and its major key determinants insulin resistance and hyperglycemia are known risk factors for calcific aortic valve disease (CAVD). The processes leading to molecular and structural alterations of the aortic valve are yet not fully understood. In previous studies, we could show that valvular interstitial cells (VIC) display canonical elements of classical insulin signaling and develop insulin resistance upon hyperinsulinemia and hyperglycemia accompanied by impaired glucose metabolism. Analyses of cultured VIC and aortic valve tissue revealed extracellular matrix remodeling and degenerative processes. Since PI3K signaling through mammalian target of rapamycin (mTOR) is involved in fibrotic processes of the heart, we aim at further functional investigation of this particular Akt-downstream signaling pathway in the context of diabetes-induced CAVD. Primary cultures of VIC were treated with hyperinsulinemia and hyperglycemia. Phosphorylation of mTOR(Ser(2448)) was determined by Western blot analysis after acute insulin stimulus. Inhibition of mTOR phosphorylation was performed by rapamycin. Phosphorylation of mTOR complex 1 (MTORC1) downstream substrates 4E-BP1(Thr(37/46)) and P70S6K(Thr(389)), and MTORC2 downstream substrate Akt(Ser(473)) as well as the PDK1-dependent phosphorylation of Akt(Thr(308)) was investigated. Markers for extracellular matrix remodeling, cell differentiation and degenerative changes were analyzed by Western blot analysis, semi-quantitative real-time PCR and colorimetric assays. Hyperinsulinemia and hyperglycemia lead to alterations of VIC activation, differentiation and matrix remodeling as well as to an abrogation of mTOR phosphorylation. Inhibition of mTOR signaling by rapamycin leads to a general downregulation of matrix molecules, but to an upregulation of alpha-smooth muscle actin expression and alkaline phosphatase activity. Comparison of expression patterns upon diabetic conditions and rapamycin treatment reveal a possible regulation of particular matrix components and key degeneration markers by MTORC1 downstream signaling. The present findings broaden the understanding of mitogenic signaling pathways in VIC triggered by hyperinsulinemia and hyperglycemia, supporting the quest for developing strategies of prevention and tailored treatment of CAVD in diabetic patients. CI - Copyright (c) 2022 Selig, Krug, Kuppers, Ouwens, Kraft, Adler, Bauer, Lichtenberg, Akhyari and Barth. FAU - Selig, Jessica I AU - Selig JI AD - Department of Cardiac Surgery, Medical Faculty, University Hospital Dusseldorf, Heinrich Heine University Dusseldorf, Dusseldorf, Germany. FAU - Krug, H Viviana AU - Krug HV AD - Department of Cardiac Surgery, Medical Faculty, University Hospital Dusseldorf, Heinrich Heine University Dusseldorf, Dusseldorf, Germany. FAU - Kuppers, Caroline AU - Kuppers C AD - Department of Cardiac Surgery, Medical Faculty, University Hospital Dusseldorf, Heinrich Heine University Dusseldorf, Dusseldorf, Germany. FAU - Ouwens, D Margriet AU - Ouwens DM AD - Institute of Clinical Biochemistry and Pathobiochemistry, German Diabetes Center (DDZ), Dusseldorf, Germany. AD - German Center for Diabetes Research (DZD), Munich, Germany. AD - Department of Endocrinology, Ghent University Hospital, Ghent, Belgium. FAU - Kraft, Felix A AU - Kraft FA AD - Department of Cardiac Surgery, Medical Faculty, University Hospital Dusseldorf, Heinrich Heine University Dusseldorf, Dusseldorf, Germany. FAU - Adler, Elena AU - Adler E AD - Department of Cardiac Surgery, Medical Faculty, University Hospital Dusseldorf, Heinrich Heine University Dusseldorf, Dusseldorf, Germany. FAU - Bauer, Sebastian J AU - Bauer SJ AD - Department of Cardiac Surgery, Medical Faculty, University Hospital Dusseldorf, Heinrich Heine University Dusseldorf, Dusseldorf, Germany. FAU - Lichtenberg, Artur AU - Lichtenberg A AD - Department of Cardiac Surgery, Medical Faculty, University Hospital Dusseldorf, Heinrich Heine University Dusseldorf, Dusseldorf, Germany. FAU - Akhyari, Payam AU - Akhyari P AD - Department of Cardiac Surgery, Medical Faculty, University Hospital Dusseldorf, Heinrich Heine University Dusseldorf, Dusseldorf, Germany. FAU - Barth, Mareike AU - Barth M AD - Department of Cardiac Surgery, Medical Faculty, University Hospital Dusseldorf, Heinrich Heine University Dusseldorf, Dusseldorf, Germany. LA - eng PT - Journal Article DEP - 20221031 PL - Switzerland TA - Front Cardiovasc Med JT - Frontiers in cardiovascular medicine JID - 101653388 PMC - PMC9661395 OTO - NOTNLM OT - MTORC1/2 OT - calcific aortic valve disease (CAVD) OT - hyperglycemia OT - hyperinsulinemia OT - insulin resistance OT - mammalian target of rapamycin (mTOR) OT - rapamycin OT - valvular interstitial cells (VIC) COIS- The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. EDAT- 2022/11/18 06:00 MHDA- 2022/11/18 06:01 PMCR- 2022/01/01 CRDT- 2022/11/17 11:42 PHST- 2022/05/12 00:00 [received] PHST- 2022/10/12 00:00 [accepted] PHST- 2022/11/17 11:42 [entrez] PHST- 2022/11/18 06:00 [pubmed] PHST- 2022/11/18 06:01 [medline] PHST- 2022/01/01 00:00 [pmc-release] AID - 10.3389/fcvm.2022.942430 [doi] PST - epublish SO - Front Cardiovasc Med. 2022 Oct 31;9:942430. doi: 10.3389/fcvm.2022.942430. eCollection 2022.