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  • The neuroprotective action of candesartan is related to interference with the early stages of 6-hydroxydopamine-induced dopaminergic cell death. 21936877

    Several studies have revealed that manipulation of the renin angiotensin system results in reduced progression of nigrostriatal damage in different animal models of Parkinson's disease. In the present work, the effect of daily treatment of rats with the angiotensin II (Ang II) type 1 (AT(1) ) receptor antagonist candesartan (3 mg/kg per day, s.c.) initiated 7 days before the intrastriatal injection of 6-hydroxydopamine (6-OHDA) was investigated by means of tyrosine hydroxylase-positive cell counts in the substantia nigra, and dopamine and 3,4-dihydroxyphenylacetic acid measurements in the striatum. In this experimental set-up, candesartan protected dopaminergic neurons of the nigrostriatal tract against the neurotoxin-induced cell death. However, the beneficial effects of AT(1) receptor blockade were not confirmed when treatment was started 24 h after the lesion, suggesting that candesartan interferes with the early events of the 6-OHDA-induced cell death. Stimulation of the AT(1) receptor with Ang II increased the formation of hydroxyl radicals in the striatum of intact rats as measured by the in vivo microdialysis salicylate trapping technique. This Ang II-induced production of reactive oxygen species was suppressed by candesartan perfusion. Furthermore, the Ang II-induced production of reactive oxygen species was nicotinamide adenine dinucleotide phosphate - oxidase and protein kinase C dependent as it could be blocked in the presence of apocynin, an nicotinamide adenine dinucleotide phosphate - oxidase inhibitor, and chelerythrine, an inhibitor of protein kinase C. Together, these data further support the hypothesis that Ang II might contribute in an early stage to the neurotoxicity of 6-OHDA by reinforcing the cascade of oxidative stress.
    Tipo de documento:
    Referencia
    Referencia del producto:
    AB152
    Nombre del producto:
    Anti-Tyrosine Hydroxylase Antibody

  • Angiotensin II and alpha(v)beta(3) integrin expression in rat neonatal cardiac fibroblasts. 10775572

    We recently demonstrated that alpha(v)beta(3) integrins are involved in the mechanisms of angiotensin II (Ang II)-induced DNA synthesis and collagen gel contractions in rat cardiac fibroblasts (CFBs), cellular mechanisms that are relevant for cardiac remodeling. The aim of the present study was to elucidate the effect of Ang II and other growth factors on the regulation of the alpha(v)beta(3) integrins in fibroblasts from neonatal rat hearts. The alpha(v)beta(3) integrin receptor expression was significantly increased (P0.05) at the mRNA level after treatment with Ang II, transforming growth factor-beta(1) (TGF-beta(1)), and platelet-derived growth factor (PDGF) for 8 and 16 hours. The surface expression of the alpha(v) and beta(3) integrin subunits was elevated after 32 and 48 hours (P0.05) as determined with flow cytometry. To investigate fibroblast motility, we performed chemotaxis experiments with transwell chambers. Ang II was chemotactic for CFBs, as tested with checkerboard experiments. The chemotactic effect was concentration dependent and was completely blocked by Ang II type 1 receptor blockers but not by Ang II type 2 receptor blocker PD 123319. Ang II- and PDGF-BB-mediated chemotaxis could be significantly inhibited by RGD peptides and the blocking antibodies against alpha(v)beta(3) integrin (both P0.01). Adhesion of CFBs to vitronectin was partially inhibited by an antibody to alpha(v)beta(3) integrin but was mainly mediated by an alpha(v)beta(5) integrin. Relevant in vivo expression of alpha(v)beta(3) integrin by CFBs was confirmed with in situ hybridization with probes for alpha(v) and beta(3) mRNA in rat hearts. The present study demonstrates that the expression of alpha(v)beta(3) integrin is augmented by Ang II, PDGF, and TGF-beta(1) in neonatal CFBs. Furthermore, this integrin is involved in the chemotaxis, motility, and adhesion of CFBs. The present findings support the current concept that integrins participate in the control of fibroblast behavior during cardiac remodeling mechanisms.
    Tipo de documento:
    Referencia
    Referencia del producto:
    AB1930
    Nombre del producto:
    Anti-Integrin alphaV Antibody, CT, Intracellular

  • Angiotensin II-induced stimulation of p21-activated kinase and c-Jun NH2-terminal kinase is mediated by Rac1 and Nck. 11279250

    p21-activated kinase (PAK) has been shown to be an upstream mediator of JNK in angiotensin II (AngII) signaling. Little is known regarding other signaling molecules involved in activation of PAK and JNK by AngII. Rho family GTPases Rac and Cdc42 have been shown to enhance PAK activity by binding to p21-binding domain of PAK (PAK-PBD). In vascular smooth muscle cells (VSMC) AngII stimulated Rac1 binding to GST-PAK-PBD fusion protein. Pretreatment of VSMC by genistein inhibited AngII-induced Rac1 activation, whereas Src inhibitor PP1 had no effect. Inhibition of protein kinase C by phorbol 12,13-dibutyrate pretreatment also decreased AngII-mediated activation of Rac1. The adaptor molecule Nck has been shown previously to mediate PAK activation by facilitating translocation of PAK to the plasma membrane. In VSMC AngII stimulated translocation of Nck and PAK to the membrane fraction. Overexpression of dominant-negative Nck in Chinese hamster ovary (CHO) cells, stably expressing the AngII type I receptor (CHO-AT1), inhibited both PAK and JNK activation by AngII, whereas it did not affect ERK1/2. Finally, dominant-negative Nck inhibited AngII-induced DNA synthesis in CHO-AT1 cells. Our data provide evidence for Rac1 and Nck as upstream mediators of PAK and JNK in AngII signaling and implicate JNK in AngII-induced growth responses.
    Tipo de documento:
    Referencia
    Referencia del producto:
    Múltiplo
    Nombre del producto:
    Múltiplo

  • Pig kidney angiotensin converting enzyme. Purification and characterization of amphipathic and hydrophilic forms of the enzyme establishes C-terminal anchorage to the pla ... 2825659

    Angiotensin converting enzyme from pig kidney was isolated by affinity chromatography after solubilization from the membrane by one of four different procedures. Solubilization with Triton X-100, trypsin or by an endogenous activity in microvillar membranes all generated hydrophilic forms of the enzyme as assessed by phase separation in Triton X-114 and failure to incorporate into liposomes. Only when solubilization and purification was effected by Triton X-100 in the presence of EDTA (10 mM) could an amphipathic form of the enzyme (membrane- or m-form) be generated. The m-form of angiotensin converting enzyme (ACE) appeared slightly larger (Mr approx. 180,000) than the hydrophilic forms (Mr approx. 175,000) after SDS/polyacrylamide-gel electrophoresis, and the m-form incorporated into liposomes, consistent with retention of the membrane anchor. The m-form of ACE showed an N-terminal sequence identical with that of preparations of enzyme isolated after solubilization with detergent alone (d-form), with trypsin (t-form) or by the endogenous mechanism (e-form). These data imply that ACE is anchored to the plasma membrane via its C-terminus, in contrast with the N-terminal anchorage of endopeptidase-24.11. No release of ACE from the membrane could be detected with a variety of phospholipases, including bacterial phosphatidylinositol-specific phospholipases C, although an endogenous EDTA-sensitive membrane-associated hydrolase was capable of releasing a soluble, hydrophilic, form of the enzyme.
    Tipo de documento:
    Referencia
    Referencia del producto:
    Múltiplo
    Nombre del producto:
    Múltiplo

  • Distribution of angiotensin type 1a receptor-containing cells in the brains of bacterial artificial chromosome transgenic mice. 22922351

    In the central nervous system, angiotensin II (AngII) binds to angiotensin type 1 receptors (AT(1)Rs) to affect autonomic and endocrine functions as well as learning and memory. However, understanding the function of cells containing AT(1)Rs has been restricted by limited availability of specific antisera, difficulties discriminating AT(1)R-immunoreactive cells in many brain regions and, the identification of AT(1)R-containing neurons for physiological and molecular studies. Here, we demonstrate that an Agtr1a bacterial artificial chromosome (BAC) transgenic mouse line that expresses type A AT(1)Rs (AT1aRs) identified by enhanced green fluorescent protein (EGFP) overcomes these shortcomings. Throughout the brain, AT1aR-EGFP was detected in the nuclei and cytoplasm of cells, most of which were neurons. EGFP often extended into dendritic processes and could be identified either natively or with immunolabeling of GFP. The distribution of AT1aR-EGFP cells in brain closely corresponded to that reported for AngII binding and AT1aR protein and mRNA. In particular, AT1aR-EGFP cells were in autonomic regions (e.g., hypothalamic paraventricular nucleus, central nucleus of the amygdala, parabrachial nucleus, nuclei of the solitary tract and rostral ventrolateral medulla) and in regions involved in electrolyte and fluid balance (i.e., subfornical organ) and learning and memory (i.e., cerebral cortex and hippocampus). Additionally, dual label electron microscopic studies in select brain areas demonstrate that cells containing AT1aR-EGFP colocalize with AT(1)R-immunoreactivity. Assessment of AngII-induced free radical production in isolated EGFP cells demonstrated feasibility of studies investigating AT1aR signaling ex vivo. These findings support the utility of Agtr1a BAC transgenic reporter mice for future studies understanding the role of AT(1)R-containing cells in brain function.
    Tipo de documento:
    Referencia
    Referencia del producto:
    Múltiplo
    Nombre del producto:
    Múltiplo

  • Calpain-2 compensation promotes angiotensin II-induced ascending and abdominal aortic aneurysms in calpain-1 deficient mice. 23977256

    Recently, we demonstrated that angiotensin II (AngII)-infusion profoundly increased both aortic protein and activity of calpains, calcium-activated cysteine proteases, in mice. In addition, pharmacological inhibition of calpain attenuated AngII-induced abdominal aortic aneurysm (AA) in mice. Recent studies have shown that AngII infusion into mice leads to aneurysmal formation localized to the ascending aorta. However, the precise functional contribution of calpain isoforms (-1 or -2) in AngII-induced abdominal AA formation is not known. Similarly, a functional role of calpain in AngII-induced ascending AA remains to be defined. Using BDA-410, an inhibitor of calpains, and calpain-1 genetic deficient mice, we examined the relative contribution of calpain isoforms in AngII-induced ascending and abdominal AA development.To investigate the relative contribution of calpain-1 and -2 in development of AngII-induced AAs, male LDLr -/- mice that were either calpain-1 +/+ or -/- were fed a saturated fat-enriched diet and infused with AngII (1,000 ng/kg/min) for 4 weeks. Calpain-1 deficiency had no significant effect on body weight or blood pressure during AngII infusion. Moreover, calpain-1 deficiency showed no discernible effects on AngII-induced ascending and abdominal AAs. Interestingly, AngII infusion induced increased expression of calpain-2 protein, thus compensating for total calpain activity in aortas of calpain-1 deficient mice. Oral administration of BDA-410, a calpain inhibitor, along with AngII-infusion significantly attenuated AngII-induced ascending and abdominal AA formation in both calpain-1 +/+ and -/- mice as compared to vehicle administered mice. Furthermore, BDA-410 administration attenuated AngII-induced aortic medial hypertrophy and macrophage accumulation. Western blot and immunostaining analyses revealed BDA-410 administration attenuated AngII-induced C-terminal fragmentation of filamin A, an actin binding cytoskeletal protein in aorta.Calpain-2 compensates for loss of calpain-1, and both calpain isoforms are involved in AngII-induced aortic aneurysm formation in mice.
    Tipo de documento:
    Referencia
    Referencia del producto:
    MAB1622
    Nombre del producto:
    Anti-Spectrin alpha chain (nonerythroid) Antibody, clone AA6

  • An angiotensin II- and NF-kappaB-dependent mechanism increases connexin 43 in murine arteries targeted by renin-dependent hypertension. 20110337

    Connexins (Cxs) play a role in the contractility of the aorta wall. We investigated how connexins of the endothelial cells (ECs; Cx37, Cx40) and smooth muscle cells (SMCs; Cx43, Cx45) of the aorta change during renin-dependent and -independent hypertension.We subjected both wild-type (WT) mice and mice lacking Cx40 (Cx40(-/-)), to either a two-kidney, one-clip procedure or to N-nitro-l-arginine-methyl-ester treatment, which induce renin-dependent and -independent hypertension, respectively. All hypertensive mice featured a thickened aortic wall, increased levels of Cx37 and Cx45 in SMC, and of Cx40 in EC (except in Cx40(-/-) mice). Cx43 was up-regulated, with no effect on its S368 phosphorylation, only in the SMCs of renin-dependent models of hypertension. Blockade of the renin-angiotensin system of Cx40(-/-) mice normalized blood pressure and prevented both aortic thickening and Cx alterations. Ex vivo exposure of WT aortas, carotids, and mesenteric arteries to physiologically relevant levels of angiotensin II (AngII) increased the levels of Cx43, but not of other Cx. In the aortic SMC line of A7r5 cells, AngII activated kinase-dependent pathways and induced binding of the nuclear factor-kappa B (NF-kappaB) to the Cx43 gene promoter, increasing Cx43 expression.In both large and small arteries, hypertension differently regulates Cx expression in SMC and EC layers. Cx43 is selectively increased in renin-dependent hypertension via an AngII activation of the extracellular signal-regulated kinase and NF-kappaB pathways.
    Tipo de documento:
    Referencia
    Referencia del producto:
    Múltiplo
    Nombre del producto:
    Múltiplo

  • Localization of type-2 angiotensin II receptor in adrenal gland. 20231739

    The localization of the type-2 angiotensin II receptor (AT2) in the adrenal glands of rats, guinea pigs, bovines, and humans was examined at the mRNA and protein levels. PCR products for AT2 were detected in the adrenal cortices and adrenal medullae of all the mammals examined with an RT-PCR technique. Three different anti-AT2 antibodies (Abs), whose specificity was confirmed in our hands, recognized a 50-kDa protein in the adrenal glands of the four mammals, and this recognition was abolished by the preabsorption of an Ab with an antigen. Immunoblotting and immunohistochemistry revealed that the 50-kDa protein was expressed consistently and variably in the adrenal cortices and medullae of various mammals, respectively. We conclude that the 50-kDa AT2 is consistently expressed in the adrenal cortex in a wide variety of mammals.
    Tipo de documento:
    Referencia
    Referencia del producto:
    Múltiplo
    Nombre del producto:
    Múltiplo

  • Metabolic Syndrome Induces Over Expression of the Human AT1R: A Haplotype-Dependent Effect With Implications on Cardio-Renal Function. 29036458

    The transcriptional regulation of the human angiotensin receptor subtype 1 (AT1R) gene in pathophysiologies, like the metabolic syndrome, is poorly understood. The human AT1R gene has polymorphisms in its promoter that can be arranged in 2 haplotypes. Variants -810T, -713T, -214A, and -153A always occur together (Hap-I) and variants -810A, -713G, -214C, and -153G form Hap-II. We have hypothesized that high fat diet will alter cellular transcriptional milieu and increase hAT1R gene expression in a haplotype-dependent manner. This will set up an AT1R-mediated feed-forward loop promoting inflammation, oxidative stress, and hypertension in Hap-I mice.Since Hap-I of the human AT1R gene is associated with hypertension in Caucasians, we generated transgenic (TG) mice with Hap-I and Hap-II and studied the physiological significance of high fat diet (HFD) on haplotype specific gene expression. Animals were fed with HFD for 20 weeks followed by blood pressure (BP) analysis and collection of their tissues for molecular and biochemical studies.After HFD treatment, as compared to Hap-II, TG mice with Hap-I show increased expression of hAT1R gene and higher BP; suppression of antioxidant defenses (HO1, SOD1) and increased expression of IL-6, TNFα, IL-1β, NOX1. In vivo ChIP assay has shown that transcription factors CEBPβ, STAT3, and USF bind more strongly to the chromatin obtained from Hap-I TG mice.Taken together, our results suggest, that after HFD treatment, as compared to Hap-II, the TG mice with Hap-I overexpress the AT1R gene due to the stronger transcriptional activity, thus resulting in an increase in their BP.
    Tipo de documento:
    Referencia
    Referencia del producto:
    17-371
    Nombre del producto:
    EZ-ChIP™

  • Calcium-dependent epidermal growth factor receptor transactivation mediates the angiotensin II-induced mitogen-activated protein kinase activation in vascular smooth musc ... 9535870

    We have recently reported that angiotensin II (Ang II)-induced mitogen-activated protein kinase (MAPK) activation is mainly mediated by Ca2+-dependent activation of a protein tyrosine kinase through Gq-coupled Ang II type 1 receptor in cultured rat vascular smooth muscle cells (VSMC). In the present study, we found Ang II rapidly induced the tyrosine phosphorylation of the epidermal growth factor (EGF) receptor and its association with Shc and Grb2. These reactions were inhibited by the EGF receptor kinase inhibitor, AG1478. The Ang II-induced phosphorylation of the EGF receptor was mimicked by a Ca2+ ionophore and completely inhibited by an intracellular Ca2+ chelator. Thus, AG1478 abolished the MAPK activation induced by Ang II, a Ca2+ ionophore as well as EGF but not by a phorbol ester or platelet-derived growth factor-BB in the VSMC. Moreover, Ang II induced association of EGF receptor with catalytically active c-Src. This reaction was not affected by AG1478. These data indicate that Ang II induces Ca2+-dependent transactivation of the EGF receptor which serves as a scaffold for pre-activated c-Src and for downstream adaptors, leading to MAPK activation in VSMC.
    Tipo de documento:
    Referencia
    Referencia del producto:
    06-498