Beate Boehme1, Nadeshda Schelski1, Manousos Makridakis2, Laura Henze1, Antonia Vlahou2, Florian Lang3, Burkert Pieske1,4,5,6, Ioana Alesutan1,4,6, Jakob Voelkl1,6. 1. Department of Internal Medicine and Cardiology, Charité - Universitätsmedizin Berlin, Campus Virchow-Klinikum, Berlin, Germany. 2. Biomedical Research Foundation, Academy of Athens, Athens, Greece. 3. Department of Physiology I, Eberhard-Karls University, Tübingen, Germany. 4. Berlin Institute of Health (BIH), Berlin, Germany. 5. Department of Internal Medicine and Cardiology, German Heart Institute Berlin, Berlin, Germany. 6. DZHK (German Centre for Cardiovascular Research), partner site Berlin, Berlin, Germany.
Abstract
BACKGROUND/AIMS: Hyperphosphatemia promotes medial vascular calcification, at least partly, by induction of osteo-/chondrogenic transdifferentiation of vascular smooth muscle cells (VSMCs). The complex signaling pathways regulating this process are still incompletely understood. The present study investigated the role of cytosolic serine hydroxymethyl transferase 1 (SHMT1) in phosphate-induced vascular calcification. METHODS: Endogenous expression of SHMT1 was suppressed by silencing in primary human aortic smooth muscle cells (HAoSMCs) followed by treatment without and with phosphate or antioxidants. RESULTS: In HAoSMCs, SHMT1 mRNA expression was up-regulated by phosphate. Silencing of SHMT1 alone was sufficient to induce osteo-/chondrogenic transdifferentiation of HAoSMCs, as shown by increased tissue-nonspecific alkaline phosphatase (ALPL) activity and osteogenic markers MSX2, CBFA1 and ALPL mRNA expression. Furthermore, phosphate-induced ALPL mRNA expression and activity as well as calcification were augmented in SHMT1 silenced HAoSMCs as compared to negative control siRNA transfected HAoSMCs. Silencing of SHMT1 decreased total antioxidant capacity and up-regulated NADH/NADPH oxidase system components NOX4 and CYBA mRNA expression in HAoSMCs, effects paralleled by increased mRNA expression of matrix metalloproteinase MMP2 as well as BAX/BCL2 ratio. More importantly, additional treatment with antioxidants TEMPOL or TIRON blunted the increased osteogenic markers mRNA expression in SHMT1 silenced HAoSMCs. CONCLUSION: Silencing of SHMT1 promotes osteo-/chondrogenic signaling in VSMCs, at least in part, by inducing cellular oxidative stress. It thus aggravates phosphate-induced calcification of VSMCs. The present findings support a regulatory role of SHMT1 in vascular calcification during conditions of hyperphosphatemia such as chronic kidney disease.
BACKGROUND/AIMS: Hyperphosphatemia promotes medial vascular calcification, at least partly, by induction of osteo-/chondrogenic transdifferentiation of vascular smooth muscle cells (VSMCs). The complex signaling pathways regulating this process are still incompletely understood. The present study investigated the role of cytosolic serine hydroxymethyl transferase 1 (SHMT1) in phosphate-induced vascular calcification. METHODS: Endogenous expression of SHMT1 was suppressed by silencing in primary human aortic smooth muscle cells (HAoSMCs) followed by treatment without and with phosphate or antioxidants. RESULTS: In HAoSMCs, SHMT1 mRNA expression was up-regulated by phosphate. Silencing of SHMT1 alone was sufficient to induce osteo-/chondrogenic transdifferentiation of HAoSMCs, as shown by increased tissue-nonspecific alkaline phosphatase (ALPL) activity and osteogenic markers MSX2, CBFA1 and ALPL mRNA expression. Furthermore, phosphate-induced ALPL mRNA expression and activity as well as calcification were augmented in SHMT1 silenced HAoSMCs as compared to negative control siRNA transfected HAoSMCs. Silencing of SHMT1 decreased total antioxidant capacity and up-regulated NADH/NADPH oxidase system components NOX4 and CYBA mRNA expression in HAoSMCs, effects paralleled by increased mRNA expression of matrix metalloproteinase MMP2 as well as BAX/BCL2 ratio. More importantly, additional treatment with antioxidants TEMPOL or TIRON blunted the increased osteogenic markers mRNA expression in SHMT1 silenced HAoSMCs. CONCLUSION: Silencing of SHMT1 promotes osteo-/chondrogenic signaling in VSMCs, at least in part, by inducing cellular oxidative stress. It thus aggravates phosphate-induced calcification of VSMCs. The present findings support a regulatory role of SHMT1 in vascular calcification during conditions of hyperphosphatemia such as chronic kidney disease.
Authors: Zhiping Cao; Jessica Minnier; Lijuan Liu; Kristin L Lyon Scott; Ashok P Reddy; Phillip A Wilmarth; Larry L David; Anthony P Barnes; Marjorie R Grafe; Sanjiv Kaul; Nabil J Alkayed; Catherine M Davis Journal: Sci Rep Date: 2022-05-25 Impact factor: 4.996
Authors: Laura A Henze; Trang T D Luong; Beate Boehme; Jaber Masyout; Markus P Schneider; Sebastian Brachs; Florian Lang; Burkert Pieske; Andreas Pasch; Kai-Uwe Eckardt; Jakob Voelkl; Ioana Alesutan Journal: Aging (Albany NY) Date: 2019-08-03 Impact factor: 5.682