Increased Angiotensin II AT1 receptor mRNA and binding in spleen and lung of AT2 receptor gene disrupted mice

Pavel, Jaroslav; Terrón, José A.; Benický, Július; Falcón-Neri, Alicia; Rachakonda, Amita; Inagami, Tadashi; Saavedra, Juan M.

doi:10.1016/j.regpep.2009.09.004

Cited by 12 publications

(9 citation statements)

References 70 publications

(180 reference statements)

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“…AT 1 receptor expression in VSMCs is decreased with AT 2 receptor over-expression and increased in some organs, such as the lung and adrenal gland, of AT 2 receptor knockout mice [9,10,32,33]. However, the mechanism by which the AT 2 receptor opposes the effect of the AT 1 receptor on sodium transport is not clear.…”

Section: Discussionmentioning

confidence: 99%

Angiotensin II AT2 receptor decreases AT1 receptor expression and function via nitric oxide/cGMP/Sp1 in renal proximal tubule cells from Wistar–Kyoto rats

Yang

Chen

Ren

et al. 2012

Journal of Hypertension

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Background The renin–angiotensin (Ang) system controls blood pressure, in part, by regulating renal tubular sodium transport. In the kidney, activation of the angiotensin II type 1 (AT1) receptor increases renal sodium reabsorption, whereas the angiotensin II type 2 (AT2) receptor produces the opposite effect. We hypothesized that the AT2 receptor regulates AT1 receptor expression and function in the kidney. Methods and results In immortalized renal proximal tubule (RPT) cells from Wistar–Kyoto rats, CGP42112, an AT2 receptor agonist, decreased AT1 receptor mRNA and protein expression (P < 0.05), as assessed by reverse transcriptase-polymerase chain reaction and immunoblotting. The inhibitory effect of the AT2 receptor on AT1 receptor expression was blocked by the AT2 receptor antagonist, PD123319 (10−6 mol/l), the nitric oxide synthase inhibitor Nw-nitro-l-arginine methyl ester (10−4 mol/l), or the nitric oxide-dependent soluble guanylate cyclase inhibitor 1H-[1,2,4] oxadiazolo-[4,3-a] quinoxalin-1-one (10−5 mol/l), indicating that both nitric oxide and cyclic guanosine monophosphate (cGMP) were involved in the signaling pathway. Furthermore, CGP42112 decreased Sp1 serine phosphorylation and reduced the binding of Sp1 to AT1 receptor DNA. Stimulation with Ang II (10−11 mol/l per 30 min) enhanced Na+-K+-ATPase activity in RPT cells, which was prevented by pretreatment with CGP42112 (10−7 mol/l per 24 h) (P < 0.05). The above-mentioned results were confirmed in RPT cells from AT2 receptor knockout mice; AT1 receptor expression and Ang II-stimulated Na+-K+-ATPase activity were greater in these cells than in RPT cells from wild-type mice (P < 0.05). AT1/AT2 receptors co-localized and co-immunoprecipitated in RPT cells; short-term CGP42112 (10−7 mol/l per 30 min) treatment increased AT1/AT2 receptor co-immunoprecipitation (P < 0.05). Conclusions These results indicate that the renal AT2 receptor, via nitric oxide/cGMP/Sp1 pathway, regulates AT1 receptor expression and function, which may be important in the regulation of sodium excretion and blood pressure.

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Section: Discussionmentioning

confidence: 99%

Angiotensin II AT2 receptor decreases AT1 receptor expression and function via nitric oxide/cGMP/Sp1 in renal proximal tubule cells from Wistar–Kyoto rats

Yang

Chen

Ren

et al. 2012

Journal of Hypertension

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“…Interestingly, this negative regulation seems to have “tonic” characteristics because higher AT1R expression could be observed when AT2R signaling was blocked genetically or pharmacologically. In some organs and tissues, including the hypothalamus, adrenal gland, kidney, liver, spleen, lung, and aorta, AT2R gene-deficient mice exhibit significantly higher AT1R expression and mRNA compared with wild-type mice 49–52 . Pharmacological inhibition of AT2R by PD123319 in adult rats has been reported to enhance AT1R expression in the brain 53 .…”

Section: Discussionmentioning

confidence: 99%

Ontogeny of angiotensin type 2 and type 1 receptor expression in mice

Gao

Chao

Parbhu

et al. 2012

J Renin Angiotensin Aldosterone Syst

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In the current experiment, we determined AT2R and AT1R protein expression by Western blot analysis in developing normal mice. The results indicate that, (1) in all detected brain regions and in the spinal cord, adult mice exhibited significantly higher AT2R expression and lower AT1R expression in total protein extracts compared to fetuses and neonates; (2) other major organs, including heart, lung, liver, and kidney, exhibited the same expression pattern as the brain and spinal cord; (3) reciprocal changes in AT2R and AT1R expression were found in the total protein extracts from the brainstems of mice from one day prenatal to six weeks of age. There was a negative correlation between AT2R and AT1R protein expression; (4) in both membrane and cytosolic fractions from the brainstem, adult mice exhibited higher AT2R and lower AT1R expression than did fetuses and neonates; (5) in the brainstem, there were no significant differences in AT2R and AT1R mRNA levels among fetal, neonatal, and adult mice. The above results reconfirmed our previous finding in rats that adult animals have higher AT2R and lower AT1R expression compared to fetuses and neonates. These data imply an involvement of AT1R in fetal development and of AT2R in adult function.

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“…Using real-time PCR, we found no differences in AT1 receptor expression conferred by CS exposure ( Figure 7A). Angiotensin receptors are known to be expressed on lung epithelial cells, with AT1 localized primarily to the lung parenchyma (16,17).…”

Section: Figurementioning

confidence: 99%

Angiotensin receptor blockade attenuates cigarette smoke–induced lung injury and rescues lung architecture in mice

et al. 2012

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Chronic obstructive pulmonary disease (COPD) is a prevalent smoking-related disease for which no diseasealtering therapies currently exist. As dysregulated TGF-β signaling associates with lung pathology in patients with COPD and in animal models of lung injury induced by chronic exposure to cigarette smoke (CS), we postulated that inhibiting TGF-β signaling would protect against CS-induced lung injury. We first confirmed that TGF-β signaling was induced in the lungs of mice chronically exposed to CS as well as in COPD patient samples. Importantly, key pathological features of smoking-associated lung disease in patients, e.g., alveolar injury with overt emphysema and airway epithelial hyperplasia with fibrosis, accompanied CS-induced alveolar cell apoptosis caused by enhanced TGF-β signaling in CS-exposed mice. Systemic administration of a TGF-β-specific neutralizing antibody normalized TGF-β signaling and alveolar cell death, conferring improved lung architecture and lung mechanics in CS-exposed mice. Use of losartan, an angiotensin receptor type 1 blocker used widely in the clinic and known to antagonize TGF-β signaling, also improved oxidative stress, inflammation, metalloprotease activation and elastin remodeling. These data support our hypothesis that inhibition of TGF-β signaling through angiotensin receptor blockade can attenuate CS-induced lung injury in an established murine model. More importantly, our findings provide a preclinical platform for the development of other TGF-β-targeted therapies for patients with COPD.

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Increased Angiotensin II AT1 receptor mRNA and binding in spleen and lung of AT2 receptor gene disrupted mice

Cited by 12 publications

References 70 publications

Angiotensin II AT2 receptor decreases AT1 receptor expression and function via nitric oxide/cGMP/Sp1 in renal proximal tubule cells from Wistar–Kyoto rats

Angiotensin II AT2 receptor decreases AT1 receptor expression and function via nitric oxide/cGMP/Sp1 in renal proximal tubule cells from Wistar–Kyoto rats

Ontogeny of angiotensin type 2 and type 1 receptor expression in mice

Angiotensin receptor blockade attenuates cigarette smoke–induced lung injury and rescues lung architecture in mice

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