title: ROCK/NF-κB axis-dependent augmentation of angiotensinogen by angiotensin II in primary-cultured preglomerular vascular smooth muscle cells.
abstract: In angiotensin II (ANG II)-dependent hypertension, the augmented intrarenal ANG II constricts the renal microvasculature and stimulates Rho kinase (ROCK), which modulates vascular contractile responses. Rho may also stimulate angiotensinogen (AGT) expression in preglomerular vascular smooth muscle cells (VSMCs), but this has not been established. Therefore, the aims of this study were to determine the direct interactions between Rho and ANG II in regulating AGT and other renin-angiotensin system (RAS) components and to elucidate the roles of the ROCK/NF-κB axis in the ANG II-induced AGT augmentation in primary cultures of preglomerular VSMCs. We first demonstrated that these preglomerular VSMCs express renin, AGT, angiotensin-converting enzyme, and ANG II type 1 (AT1) receptors. Furthermore, incubation with ANG II (100 pmol/l for 24 h) increased AGT mRNA (1.42 ± 0.03, ratio to control) and protein (1.68 ± 0.05, ratio to control) expression levels, intracellular ANG II levels, and NF-κB activity. In contrast, the ANG II treatment did not alter AT1a and AT1b mRNA levels in the cells. Treatment with H-1152 (ROCK inhibitor, 10 nmol/l) and ROCK1 small interfering (si) RNA suppressed the ANG II-induced AGT augmentation and the upregulation and translocalization of p65 into nuclei. Functional studies showed that ROCK exerted a greater influence on afferent arteriole responses to ANG II in rats subjected to chronic ANG II infusions. These results indicate that ROCK is involved in NF-κB activation and the ROCK/NF-κB axis contributes to ANG II-induced AGT upregulation, leading to intracellular ANG II augmentation.
authors.affiliation: Dept. of Physiology and Hypertension and Renal Center of Excellence, Tulane Univ. Health Sciences Center, 1430 Tulane Ave., SL39, New Orleans, LA 70112-2699. kmiyada@tulane.edu.
authors.forename: Kayoko
authors.initials: K
authors.lastname: Miyata
authors.forename: Ryousuke
authors.initials: R
authors.lastname: Satou
authors.forename: Weijian
authors.initials: W
authors.lastname: Shao
authors.forename: Minolfa C
authors.initials: MC
authors.lastname: Prieto
authors.forename: Maki
authors.initials: M
authors.lastname: Urushihara
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kobori
authors.forename: L Gabriel
authors.initials: LG
authors.lastname: Navar
mesh_terms: D000804:Angiotensin II / Q000502:physiology*; D000808:Angiotensinogen / Q000096:biosynthesis*; D000818:Animals; D002478:Cells, Cultured; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000166:cytology; D016328:NF-kappa B / Q000502:physiology*; D051381:Rats; D012717:Sesquiterpenes / Q000494:pharmacology; D054460:rho-Associated Kinases / Q000037:antagonists & inhibitors / Q000502:physiology*
chemical_list: D016328:NF-kappa B; D012717:Sesquiterpenes; D000808:Angiotensinogen; D000804:Angiotensin II; C002669:parthenolide; D054460:rho-Associated Kinases
keywords: H-1152; afferent arteriole; angiotensin II type 1 receptors; juxtamedullary nephron preparation; parathenolide; renin; renin-angiotensin system