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Acetylcholine Activates Cystathionine γ‐Lyase Production of H 2 S in Aortic Endothelial Cells
Author(s) -
Mendiola Perenkita,
Gonzalez Bosc Laura V,
Rios Lynnette,
Naik Jay,
Kanagy Nancy
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.837.17
Subject(s) - ionomycin , acetylcholine , cystathionine beta synthase , endogeny , chemistry , vasodilation , intracellular , endothelium , microbiology and biotechnology , biochemistry , enzyme , pharmacology , endocrinology , biology , cysteine
Hydrogen sulfide (H 2 S) is the most recently described endothelium‐derived vasodilator. In the endothelium, H 2 S is predominantly produced by cystathionine ©‐lyase (CSE). We and others have previously shown CSE inhibition diminishes acetylcholine (ACh)‐induced dilation in aortic ring segments. However, ACh regulation of CSE is not well‐defined. The goal of this study was to identify endogenous regulators of CSE in aortic endothelial cells. Previous reports show that [Ca 2+ ] regulates CSE activity. However, previous studies were conducted using 1–2 mM [Ca 2+ ] and purified CSE. Because normal intracellular [Ca 2+ ] is 100 nM to 3 μM and activity of purified enzymes may not reflect in vivo activity, it is necessary to verify regulation of endogenous CSE with physiological [Ca 2+ ]. Thus, we hypothesized that ACh‐induced increases in intracellular [Ca 2+ ] elevates CSE production of H 2 S. Rat aortic endothelial cells (passage 5–6) were loaded with the H 2 S fluorescence indicator, sulfide fluor‐7 acetoxymethylester (SF7‐AM, 10 μM), exposed to either ACh (10 μM), a Ca 2+ ionophore (ionomycin, 100 nM) or an H 2 S donor (NaHS, 10 μM). Some cells were pretreated for 30 minutes with the CSE inhibitor, β‐cyanoalanine (BCA, 100 μM) and changes in fluorescence recorded ( Figure). These findings show that ACh increases CSE production of H 2 S but this activation may not be Ca 2+ dependent since BCA did not reduce ionomycin‐induced H 2 S production. Future studies will investigate Ach‐induced Ca 2+ signaling, ionomycin regulation of other H 2 S generating enzymes and Ca 2+ ‐independent Ach signaling to further delineate endogenous regulators of CSE activity. Support or Funding Information Funding provided by HL123301 and HL121871 (NLK), AHA 15GRNT25090039 (LGB) and HL07736 (PM)