Sherin Samuel1, Kuo Zhang2, Yi-Da Tang2, A Martin Gerdes3, Maria Alicia Carrillo-Sepulveda3. 1. Department of Life Sciences, New York Institute of Technology, Old Westbury, New York, New York, USA. 2. Department of Internal Medicine, State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China. 3. Department of Biomedical Sciences, New York Institute of Technology - College of Osteopathic Medicine, Old Westbury, New York, New York, USA.
Abstract
BACKGROUND/AIMS: Vascular relaxation caused by Triiodothyronine (T3) involves direct activation of endothelial cells (EC) and vascular smooth muscle cells (VSMC). Activation of protein kinase G (PKG) has risen as a novel contributor to the vasorelaxation mechanism triggered by numerous stimuli. We hypothesize that T3-induced vasorelaxation involves PKG/vasodilator-stimulated phosphoprotein (VASP) signaling pathway in VSMC. METHODS: Human aortic endothelial cells (HAEC) and VSMC were treated with T3 for short (2 to 60 minutes) and long term (24 hours). Nitric oxide (NO) production was measured using DAF-FM. Expression of protein targets was determined using western blot. For functional studies, rat aortas were isolated and treated with T3 for 20 minutes and mounted in a wire myograph. Relaxation was measured by a concentration-dependent response to acetylcholine (ACh) and sodium nitroprusside (SNP). RESULTS: Aortas stimulated with T3 exhibited augmented sensitivity to ACh and SNP-induced relaxation, endothelium-dependent and endothelium-independent responses, respectively. T3 directly increased vasorelaxation, which was abolished in the presence of a PKG inhibitor. T3 markedly induced phosphorylation of Akt, eNOS and consequently increased NO production in EC. Likewise, T3 induced phosphorylation of VASP at serine 239 via the PKG pathway in VSMC. CONCLUSION: Our findings have uncovered a PKG/VASP signaling pathway in VSMC as a key molecular mechanism underlying T3-induced vascular relaxation.
BACKGROUND/AIMS: Vascular relaxation caused by Triiodothyronine (T3) involves direct activation of endothelial cells (EC) and vascular smooth muscle cells (VSMC). Activation of protein kinase G (PKG) has risen as a novel contributor to the vasorelaxation mechanism triggered by numerous stimuli. We hypothesize that T3-induced vasorelaxation involves PKG/vasodilator-stimulated phosphoprotein (VASP) signaling pathway in VSMC. METHODS:Human aortic endothelial cells (HAEC) and VSMC were treated with T3 for short (2 to 60 minutes) and long term (24 hours). Nitric oxide (NO) production was measured using DAF-FM. Expression of protein targets was determined using western blot. For functional studies, rat aortas were isolated and treated with T3 for 20 minutes and mounted in a wire myograph. Relaxation was measured by a concentration-dependent response to acetylcholine (ACh) and sodium nitroprusside (SNP). RESULTS: Aortas stimulated with T3 exhibited augmented sensitivity to ACh and SNP-induced relaxation, endothelium-dependent and endothelium-independent responses, respectively. T3 directly increased vasorelaxation, which was abolished in the presence of a PKG inhibitor. T3 markedly induced phosphorylation of Akt, eNOS and consequently increased NO production in EC. Likewise, T3 induced phosphorylation of VASP at serine 239 via the PKG pathway in VSMC. CONCLUSION: Our findings have uncovered a PKG/VASP signaling pathway in VSMC as a key molecular mechanism underlying T3-induced vascular relaxation.
Authors: Dina K Gaynullina; Svetlana I Sofronova; Ekaterina K Selivanova; Anastasia A Shvetsova; Anna A Borzykh; Olga S Tarasova Journal: Curr Res Physiol Date: 2021-12-14