title: Restoring nitric oxide cytosolic calcium regulation by cyclic guanosine monophosphate protein kinase I alpha transfection in coronary endothelial cells of spontaneously hypertensive rats.
abstract: In microcoronary endothelial cells (RCEs) from spontaneously hypertensive rats (SHR), the nitric oxide (NO)/cyclic guanosine monophosphate (GMP)-dependent proteinkinase I (cGKI) pathway cannot regulate the cytosolic calcium ([Ca2+]i) dynamic as in RCEs from Wistar Kyoto rats (WKY). We investigated the altered downstream NO target in SHR cells and, since cGKI expression was low, whether the re-expression of cGKIα in SHR RCEs could restore NO calcium responsiveness. We measured [Ca2+]i dynamic by fura-2 imaging analysis and the cGKI level by RT-PCR and Western blot in SHR and WKY RCEs. Plasmids encoding for enhanced green fluorescence protein or cGKIα-enhanced green fluorescence protein were transiently transfected in SHR RCEs, and [Ca2+]i was evaluated. Angiotensin-II (AT-II) increased [Ca2+]i in a concentration-dependent way in both strains. Whereas in WKY, endogenously produced NO and cyclic GMP analog decreased the AT-II-induced [Ca2+]i transient, they were ineffective in SHR RCEs. The cGKI level was low in SHR cells. However, after cGKIα re-expression, endogenous NO decreased the AT-II-induced [Ca2+]i transient, while endothelial NO synthase and cGKI inhibition prevented it. The low expression of cGKI in SHR accounts for the absent regulation of the agonist-induced [Ca2+]i transient by the NO/cyclic GMP pathway. Studies on cGKI in humans could contribute to a better understanding of cardiovascular pathologies.
authors.affiliation: Department of Anatomy, Histology and Forensic Medicine, University of Florence, Florence, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Nistri
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Di Cesare Mannelli
authors.forename: Luca
authors.initials: L
authors.lastname: Mazzetti
authors.forename: Robert
authors.initials: R
authors.lastname: Feil
authors.forename: Daniele
authors.initials: D
authors.lastname: Bani
authors.forename: Paola
authors.initials: P
authors.lastname: Failli
mesh_terms: D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D003331:Coronary Vessels / Q000378:metabolism*; D006152:Cyclic GMP / Q000502:physiology; D017869:Cyclic GMP-Dependent Protein Kinases / Q000502:physiology*; D003600:Cytosol / Q000378:metabolism*; D006973:Hypertension / Q000378:metabolism*; D008297:Male; D009569:Nitric Oxide / Q000502:physiology*; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D014162:Transfection
chemical_list: D000804:Angiotensin II; D009569:Nitric Oxide; D017869:Cyclic GMP-Dependent Protein Kinases; D006152:Cyclic GMP; D002118:Calcium