title: NFAT regulation of cystathionine γ-lyase expression in endothelial cells is impaired in rats exposed to intermittent hypoxia.
abstract: Sleep apnea is a risk factor for cardiovascular disease, and intermittent hypoxia (IH, 20 episodes/h of 5% O2-5% CO2for 7 h/day) to mimic sleep apnea increases blood pressure and impairs hydrogen sulfide (H2S)-induced vasodilation in rats. The enzyme that produces H2S, cystathionine γ-lyase (CSE), is decreased in rat mesenteric artery endothelial cells (EC) following in vivo IH exposure. In silico analysis identified putative nuclear factor of activated T cell (NFAT) binding sites in the CSE promoter. Therefore, we hypothesized that IH exposure reduces Ca2+concentration ([Ca2+]) activation of calcineurin/NFAT to lower CSE expression and impair vasodilation. In cultured rat aortic EC, inhibiting calcineurin with cyclosporine A reduced CSE mRNA, CSE protein, and luciferase activity driven by a full-length but not a truncated CSE promoter. In male rats exposed to sham or IH conditions for 2 wk, [Ca2+] in EC in small mesenteric arteries from IH rats was lower than in EC from sham rat arteries (Δfura 2 ratio of fluorescence at 340 to 380 nm from Ca2+free: IH = 0.05 ± 0.02, sham = 0.17 ± 0.03,P< 0.05), and fewer EC were NFATc3 nuclear positive in IH rat arteries than in sham rat arteries (IH = 13 ± 3, sham = 59 ± 11%,P< 0.05). H2S production was also lower in mesenteric tissue from IH rats vs. sham rats. Endothelium-dependent vasodilation to acetylcholine (ACh) was lower in mesenteric arteries from IH rats than in arteries from sham rats, and inhibiting CSE with β-cyanoalanine diminished ACh-induced vasodilation in arteries from sham but not IH rats but did not affect dilation to the H2S donor NaHS. Thus, IH lowers EC [Ca2+], NFAT activity, CSE expression and activity, and H2S production while inhibiting NFAT activation lowers CSE expression. The observations that IH exposure decreases NFATc3 activation and CSE-dependent vasodilation support a role for NFAT in regulating endothelial H2S production.NEW & NOTEWORTHYThis study identifies the calcium-regulated transcription factor nuclear factor of activated T cells as a novel regulator of cystathionine γ-lyase (CSE). This pathway is basally active in mesenteric artery endothelial cells, but, after exposure to intermittent hypoxia to mimic sleep apnea, nuclear factor of activated T cells c3 nuclear translocation and CSE expression are decreased, concomitant with decreased CSE-dependent vasodilation.
authors.affiliation: Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico.
authors.forename: Laura V
authors.initials: LV
authors.lastname: Gonzalez Bosc
authors.affiliation: Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico.
authors.forename: Jessica M
authors.initials: JM
authors.lastname: Osmond
authors.affiliation: Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico.
authors.forename: Wieslawa K
authors.initials: WK
authors.lastname: Giermakowska
authors.affiliation: Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico.
authors.forename: Carolyn E
authors.initials: CE
authors.lastname: Pace
authors.affiliation: Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico.
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Riggs
authors.affiliation: Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico.
authors.forename: Olan
authors.initials: O
authors.lastname: Jackson-Weaver
authors.affiliation: Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico nkanagy@salud.unm.edu.
authors.forename: Nancy L
authors.initials: NL
authors.lastname: Kanagy
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001483:Base Sequence; D019703:Calcineurin / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D003542:Cystathionine gamma-Lyase / Q000096:biosynthesis* / Q000235:genetics; D042783:Endothelial Cells / Q000378:metabolism*; D006862:Hydrogen Sulfide / Q000378:metabolism; D000860:Hypoxia / Q000201:enzymology / Q000378:metabolism*; D008297:Male; D008638:Mesenteric Arteries / Q000166:cytology / Q000378:metabolism; D050778:NFATC Transcription Factors / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012891:Sleep Apnea Syndromes / Q000235:genetics / Q000503:physiopathology; D014664:Vasodilation / Q000187:drug effects; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: D050778:NFATC Transcription Factors; D014665:Vasodilator Agents; D019703:Calcineurin; D003542:Cystathionine gamma-Lyase; D000109:Acetylcholine; D002118:Calcium; D006862:Hydrogen Sulfide
keywords: calcineurin; hydrogen sulfide; mesenteric arteries; nuclear factor of activated T cells c3; sleep apnea; vasodilation