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Updated: Mar 29, 2026
08:58
En Face Detection of Nitric Oxide and Superoxide in Endothelial Layer of Intact Arteries
Published on: February 25, 2016
10.2K
Citron Rho-interacting kinase mediates arsenite-induced decrease in endothelial nitric oxide synthase activity by
Jungwon Seo1, Du-Hyong Cho2, Hyeon-Ju Lee3
1Department of Molecular Medicine, Ewha Womans University Medical School, Yangcheon-gu, Seoul 158-710, South Korea; Institute of Pharmaceutical Research and Development, College of Pharmacy, Wonkwang University, Iksan, Chonbuk, South Korea.
Free Radical Biology & Medicine
|November 24, 2015
Summary
Arsenite impairs blood vessel function by increasing RhoA/CRIK/eNOS-Thr(497) phosphorylation, leading to reduced nitric oxide (NO) production. This study identifies a key molecular pathway in arsenite-induced vascular disease.
Area of Science:
- Vascular Biology
- Toxicology
- Molecular Signaling
Background:
- Arsenite acutely decreases nitric oxide (NO) production by phosphorylating endothelial NO synthase (eNOS) at threonine 497 (eNOS-Thr(497)).
- The precise molecular mechanisms driving arsenite-induced eNOS-Thr(497) phosphorylation remain incompletely understood.
Purpose of the Study:
- To elucidate the specific kinase responsible for arsenite-stimulated eNOS-Thr(497) phosphorylation.
- To investigate the role of RhoA signaling pathway in mediating this phosphorylation event.
- To determine the contribution of this pathway to arsenite-induced vascular dysfunction.
Main Methods:
- Investigated arsenite effects on eNOS-Thr(497) phosphorylation using various kinase inhibitors and dominant-negative constructs.
- Assessed RhoA activity and its downstream effectors, including Rho-associated protein kinase (ROCK) and citron Rho-interacting kinase (CRIK).
- Utilized in vitro phosphorylation assays, siRNA-mediated knockdown, and ex vivo rat aorta studies.
Main Results:
- Arsenite acutely increased RhoA activity, and dominant-negative RhoA reversed arsenite-induced eNOS-Thr(497) phosphorylation.
- While Rho-associated protein kinase (ROCK) was identified as a potential effector, its role was not definitively confirmed.
- Citron Rho-interacting kinase (CRIK) was identified as a direct kinase for eNOS-Thr(497), and its inhibition reversed arsenite-induced phosphorylation and restored eNOS activity.
- Arsenite increased eNOS-Thr(497) phosphorylation and decreased acetylcholine-induced vessel relaxation in rat aortas.
Conclusions:
- Arsenite acutely inhibits eNOS enzymatic activity and vascular relaxation.
- The RhoA/CRIK/eNOS-Thr(497) phosphorylation axis is a key molecular mechanism underlying arsenite-induced vascular impairment.
- This pathway provides critical insights into the pathogenesis of arsenite-associated vascular diseases.
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