Targeted disruption of the bradykinin B2 receptor gene in mice alters the ontogeny of the renin-angiotensin system

2001 ◽  
Vol 281 (5) ◽  
pp. F795-F801 ◽  
Author(s):  
Igor V. Yosipiv ◽  
Susana Dipp ◽  
Samir S. El-Dahr

First published July 12, 2001; 10.1152/ajprenal.0020.2001.—Angiotensin II type 1 (AT1) receptor knockout (KO) mice exhibit an activated kallikrein-kinin system (KKS) that serves to attenuate the severity of the renal vascular phenotype in these mice (Tsuchida S, Miyazaki Y, Matsusaka T, Hunley TE, Inagami T, Fogo A, and Ichikawa I, Kidney Int 56: 509–516, 1999). Conversely, gestational high salt suppresses the fetal renin-angiotensin system (RAS) and provokes aberrant renal development in bradykinin B2-KO mice (El-Dahr SS, Harrison-Bernard LM, Dipp S, Yosipiv IV, and Meleg-Smith S, Physiol Genomics 3: 121–131, 2000). Thus the cross talk between the RAS and KKS may be critical for normal renal maturation. To further define the developmental interactions between the KKS and RAS, we examined the consequences of B2 receptor gene ablation on the expression of RAS components. Renal renin mRNA levels are 50% lower in newborn B2-KO than wild-type (WT) mice. Also, the age-related decline in renin mRNA is greater in B2-KO than WT mice (3.5- vs. 2-fold, P < 0.05). Although renal angiotensinogen (Ao) protein levels are higher in newborn B2-KO than WT mice, Ao mRNA levels are not, suggesting accumulation of Ao as a result of decreased renin-mediated cleavage. Similar age-related increases (8-fold) in angiotensin I-converting enzyme (ACE) activity are observed in B2-KO and WT mice. Renal AT1 protein levels are not different in B2-KO and WT mice. Furthermore, the developmental increases in renal kallikrein mRNA and enzymatic activity are more pronounced in B2-KO compared with WT mice (mRNA: 8- vs. 3-fold; activity: 13- vs. 6-fold, P < 0.05). We conclude that 1) bradykinin stimulates renin gene expression, 2) renal kallikrein is regulated via a negative feedback loop involving the B2 receptor, and 3) Ao, ACE, and AT1 are not bradykinin-target genes.

2015 ◽  
Vol 308 (6) ◽  
pp. R517-R529 ◽  
Author(s):  
Regina Nostramo ◽  
Lidia Serova ◽  
Marcela Laukova ◽  
Andrej Tillinger ◽  
Chandana Peddu ◽  
...  

The involvement of the nonclassical renin-angiotensin system (RAS) in the adrenomedullary response to stress is unclear. Therefore, we examined basal and immobilization stress (IMO)-triggered changes in gene expression of the classical and nonclassical RAS receptors in the rat adrenal medulla, specifically the angiotensin II type 2 (AT2) and type 4 (AT4) receptors, (pro)renin receptor [(P)RR], and Mas receptor (MasR). All RAS receptors were identified, with AT2 receptor mRNA levels being the most abundant, followed by the (P)RR, AT1A receptor, AT4 receptor, and MasR. Following a single IMO, AT2 and AT4 receptor mRNA levels decreased by 90 and 50%, respectively. Their mRNA levels were also transiently decreased by repeated IMO. MasR mRNA levels displayed a 75% transient decrease as well. Conversely, (P)RR mRNA levels were increased by 50% following single or repeated IMO. Because of its abundance, the function of the (P)RR was explored in PC-12 cells. Prorenin activation of the (P)RR increased phosphorylation of extracellular signal-regulated kinase 1/2 and tyrosine hydroxylase at Ser31, likely increasing its enzymatic activity and catecholamine biosynthesis. Together, the broad and dynamic changes in gene expression of the nonclassical RAS receptors implicate their role in the intricate response of the adrenomedullary catecholaminergic system to stress.


1993 ◽  
Vol 264 (5) ◽  
pp. F874-F881 ◽  
Author(s):  
S. S. el-Dahr ◽  
J. Gee ◽  
S. Dipp ◽  
B. G. Hanss ◽  
R. C. Vari ◽  
...  

The purpose of this study was to delineate the effects of prolonged (1 and 5 wk) unilateral ureteral obstruction (UUO) on the intrarenal renin-angiotensin and kallikrein-kinin systems in the rat. Systolic blood pressure (SBP) and plasma angiotensin (ANG) II levels were significantly higher at 1 and 5 wk of obstruction than in sham-operated groups. Also, plasma renin activity and ANG I levels were elevated at 1 wk (P < 0.05), and plasma angiotensin-converting enzyme (ACE)-kininase II activity was elevated at 5 wk (P < 0.05). Blockade of ANG II receptors with losartan (Dup 753) prevented the rise in SBP after UUO and normalized SBP in chronically hypertensive UUO rats. Renin mRNA levels and ANG II content were elevated in the obstructed kidneys at 1 and 5 wk compared with sham-operated kidneys (P < 0.05). ACE-kininase II activity was elevated in both the obstructed and contralateral kidneys at 5 wk compared with sham-operated kidneys (P < 0.05). In marked contrast to renin, total immunoreactive kallikrein contents and tissue kallikrein mRNA levels in the obstructed kidneys were reduced to 25% of sham-operated kidneys both at 1 and 5 wk (P < 0.001). The results indicate that urinary obstruction activates renin and suppresses kallikrein gene expression. Activation of ACE-kininase II by UUO also serves to enhance intrarenal ANG II generation and kinin degradation. The results implicate ANG II overproduction and kinin deficiency in the pathogenesis of UUO-induced hypertension and intrarenal vasoconstriction.


1993 ◽  
Vol 264 (3) ◽  
pp. F510-F514
Author(s):  
R. Morishita ◽  
J. Higaki ◽  
H. Okunishi ◽  
F. Nakamura ◽  
M. Nagano ◽  
...  

To investigate the molecular pathology of two-kidney, one-clip (2K-1C) rats, we examined the gene expressions of the renin-angiotensin system (RAS) and angiotensin II (ANG II) concentration in various tissues in the early (4 wk) and chronic (16 wk) phases of hypertension. Four weeks after clipping, the brain renin mRNA level was lower in 2K-1C rats than in control rats (P < 0.05). On the other hand, the levels of brain and renal angiotensinogen mRNA were not significantly different in the two groups. The brain and adrenal ANG II concentrations were significantly higher in 2K-1C rats than in control rats. Sixteen weeks after clipping, there was no significant difference in the brain renin mRNA levels in the two groups, and renal and brain angiotensinogen mRNA levels were normal. Moreover, the ANG II concentrations in the adrenals and brain (except the cortex) of 2K-1C rats were not significantly higher than those in control rats. These results show a differential pattern of tissue RAS gene expression in rats during the development of 2K-1C hypertension, which is regulated in a tissue-specific manner. Furthermore, the data suggest that brain ANG II may be affected by circulating ANG II, but not by the brain renin angiotensin system, and may regulate brain renin, probably by negative feedback through its own receptor.


1989 ◽  
Vol 77 (6) ◽  
pp. 629-636 ◽  
Author(s):  
Nilesh J. Samani ◽  
John D. Swales ◽  
William J. Brammar

1. Renin messenger RNA (mRNA) levels were compared in the kidneys, livers, brains, adrenals, aortae and hearts of spontaneously hypertensive (SHR) and Wistar—Kyoto (WKY) rats at 5 and 12 weeks of age using a ribonuclease-protection technique 2. Relative levels of renin mRNA were increased in the kidney, liver, brain, adrenal and heart of the young SHR compared with the WKY. In the aorta, levels were similar in the two strains at 5 weeks 3. In 12-week-old animals, while increased levels persisted in the liver, brain and adrenal of the SHR, the level in the kidney was now the same in the two strains and the levels in the heart and aorta were lower in the SHR compared with the WKY 4. Renin mRNA levels in the kidneys of SHR and WKY were also compared by Northern blotting and confirmed the observations made with the ribonuclease-protection technique 5. The findings indicate a widespread abnormality of renin gene expression in the SHR which is modulated in some tissues by the development of hypertension 6. While the mechanism(s) for the abnormality remains to be determined, the increased renin mRNA levels in the SHR in several tissues concerned with blood pressure regulation suggests an important role for the renin-angiotensin system in the development and maintenance of hypertension 7. However, the finding of increased renin mRNA in the liver also suggests abnormalities in other, as yet unknown, functions of the renin—angiotensin system in the SHR.


2017 ◽  
Vol 312 (5) ◽  
pp. H968-H979 ◽  
Author(s):  
Neeru M. Sharma ◽  
Shyam S. Nandi ◽  
Hong Zheng ◽  
Paras K. Mishra ◽  
Kaushik P. Patel

An activated renin-angiotensin system (RAS) within the central nervous system has been implicated in sympathoexcitation during various disease conditions including congestive heart failure (CHF). In particular, activation of the RAS in the paraventricular nucleus (PVN) of the hypothalamus has been recognized to augment sympathoexcitation in CHF. We observed a 2.6-fold increase in angiotensinogen (AGT) in the PVN of CHF. To elucidate the molecular mechanism for increased expression of AGT, we performed in silico analysis of the 3′-untranslated region (3′-UTR) of AGT and found a potential binding site for microRNA (miR)-133a. We hypothesized that decreased miR-133a might contribute to increased AGT in the PVN of CHF rats. Overexpression of miR-133a in NG108 cells resulted in 1.4- and 1.5-fold decreases in AGT and angiotensin type II (ANG II) type 1 receptor (AT1R) mRNA levels, respectively. A luciferase reporter assay performed on NG108 cells confirmed miR-133a binding to the 3′-UTR of AGT. Consistent with these in vitro data, we observed a 1.9-fold decrease in miR-133a expression with a concomitant increase in AGT and AT1R expression within the PVN of CHF rats. Furthermore, restoring the levels of miR-133a within the PVN of CHF rats with viral transduction resulted in a significant reduction of AGT (1.4-fold) and AT1R (1.5-fold) levels with a concomitant decrease in basal renal sympathetic nerve activity (RSNA). Restoration of miR-133a also abrogated the enhanced RSNA responses to microinjected ANG II within the PVN of CHF rats. These results reveal a novel and potentially unique role for miR-133a in the regulation of ANG II within the PVN of CHF rats, which may potentially contribute to the commonly observed sympathoexcitation in CHF. NEW & NOTEWORTHY Angiotensinogen (AGT) expression is upregulated in the paraventricular nucleus of the hypothalamus through posttranscriptional mechanism interceded by microRNA-133a in heart failure. Understanding the mechanism of increased expression of AGT in pathological conditions leading to increased sympathoexcitation may provide the basis for the possible development of new therapeutic agents with enhanced specificity.


Endocrinology ◽  
2007 ◽  
Vol 148 (5) ◽  
pp. 2453-2457 ◽  
Author(s):  
Shigeyuki Wakahara ◽  
Tadashi Konoshita ◽  
Shinichi Mizuno ◽  
Makoto Motomura ◽  
Chikako Aoyama ◽  
...  

Angiotensin-converting enzyme (ACE) 2, a newly emerging component of the renin-angiotensin system, is presumed to be a counterregulator against ACE in generating and degrading angiotensin II. It remains to be elucidated how mRNA levels of these two genes are quantitatively regulated in the kidney and also what kind of clinicopathological characteristics could influence the gene expressions in humans. Seventy-eight cases of biopsy-proven renal conditions were examined in detail. Total RNA from a small part of each renal cortical biopsy specimen was reverse transcribed, and the resultant cDNA was amplified for ACE, ACE2, and glyceraldehyde-3-phosphate dehydrogenase with a real-time PCR system. Then we investigated the relationship between clinicopathological variables and mRNA levels adjusted for glyceraldehyde-3-phosphate dehydrogenase. Statistically significant correlation was not observed between any clinicopathological variables and either of the gene expressions by pairwise comparison. However, a strong correlation was observed between the gene expressions of ACE and those of ACE2. Moreover, the ACE to ACE2 ratio was significantly higher in subjects with hypertension (HT) than that in subjects without HT. Whereas parameters of renal function, e.g. urinary protein excretion (UPE) and creatinine clearance (Ccr), are not significantly related to the ACE to ACE2 ratio as a whole, the HT status may reflect disease-induced deterioration of renal function. That is, UPE and Ccr of subjects with HT are significantly different from those without HT, in which a significant correlation is also observed between UPE and Ccr. Finally, stepwise regression analysis further revealed that only the HT status is an independent confounding determinant of the ACE to ACE2 ratio among the variables tested. Our data suggest that ACE2 might play an important role in maintaining a balanced status of local renin-angiotensin system synergistically with ACE by counterregulatory effects confounded by the presence of hypertension. Thus, ACE2 may exert pivotal effects on cardiovascular and renal conditions.


1992 ◽  
Vol 262 (5) ◽  
pp. E651-E657 ◽  
Author(s):  
K. Kohara ◽  
K. B. Brosnihan ◽  
C. M. Ferrario ◽  
A. Milsted

We investigated whether angiotensin (ANG) II has the potential to regulate expression of genes of the renin-angiotensin system (RAS) in peripheral and central tissues. ANG II (0.1 or 6.0 nmol/h) was infused by osmotic minipump into male Sprague-Dawley rats (225-250 g) for 5 days, either intravenously or intracerebroventricularly. We measured angiotensinogen mRNA in liver, adrenal glands, and brain (hypothalamus and lower brain stem), renin mRNA in the kidney, and angiotensin-converting enzyme (ACE) mRNA in the lung and testis by Northern blot analysis. We demonstrated that plasma ANG II increases the levels of liver angiotensinogen mRNA, decreases kidney renin mRNA, and decreases lung ACE mRNA. Intracerebroventricular administration of ANG II resulted in a different pattern of responses of the peripheral RAS components. Liver angiotensinogen mRNA was increased, and kidney renin mRNA was decreased by both doses of ANG II, whereas lung ACE mRNA remained unresponsive at either dose. Centrally mediated influences of ANG II are most likely indirect since plasma ANG II concentration was not changed. This study has revealed that ANG II has profound diverse effects that influence the regulation of its formation. Further, results indicate that genes of the RAS responded to exogenous ANG II in both tissue- and route-specific ways.


1980 ◽  
Vol 238 (5) ◽  
pp. R432-R437 ◽  
Author(s):  
K. B. Wallace ◽  
J. B. Hook ◽  
M. D. Bailie

The purpose of this investigation was to correlate the development of the various enzyme activities associated with the renin-angiotensin system with age-related differences in the steady-state concentrations of angiotensin I (AI) and II (AII). Angiotensin was quantified by radioimmunoassay. Plasma renin activity and concentration increased between birth and 3 wk of age, and declined thereafter to adult values. Renal renin content, on the other hand, increased throughout the first 6 wk of postnatal life. The concentration of AII in plasma also increased following birth; however, maximum concentrations were not attained until 5 wk of age. In contrast, plasma AI did not increase between 3 and 6 wk of age. These data suggest that the steady-state concentration of AII in neonatal rat plasma may be partially limited by the low plasma renin substrate concentration. The increase in AII between 3 and 6 wk of age may reflect the increasing converting enzyme activity.


2006 ◽  
Vol 2006 ◽  
pp. 1-6 ◽  
Author(s):  
Suyeon Kim ◽  
Morvarid Soltani-Bejnood ◽  
Annie Quignard-Boulange ◽  
Florence Massiera ◽  
Michele Teboul ◽  
...  

Background. The adipose tissue renin-angiotensin system (RAS) contributes to regulation of fat mass and may also impact systemic functions such as blood pressure and metabolism.Methods and results. A panel of mouse models including mice lacking angiotensinogen,Agt(Agt-KO), mice expressingAgtsolely in adipose tissue (aP2-Agt/Agt-KO), and mice overexpressingAgtin adipose tissue (aP2-Agt) was studied. Total body weight, epididymal fat pad weight, and circulating levels of leptin, insulin, and resistin were significantly decreased inAgt-KO mice, while plasma adiponectin levels were increased. aP2-Agtmice exhibited increased adiposity and plasma leptin and insulin levels compared to wild type (WT) controls. Angiotensinogen and type I Ang II receptor protein levels were also elevated in kidney of aP2-Agtmice.Conclusion. These findings demonstrate that alterations in adipose RAS activity significantly impact both local and systemic physiology in a way that may contribute to the detrimental health effects of obesity.


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