Angiotensin II induces kidney inflammatory injury and fibrosis through binding to myeloid differentiation protein-2 (MD2).
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ABSTRACT:
SUBMITTER: Xu Z
PROVIDER: S-EPMC5359637 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Angiotensin II (Ang II) is a risk factor for the initiation and progression of chronic kidney disease (CKD), as elevated Ang II levels can lead to podocyte injury. However, there have been no studies on the role of Ang II in lipid metabolism or on podocyte injury caused by lipid dysfunction. Our study showed that Ang II induced lipid droplet (LD) accumulation and expression of the LD marker adipose differentiation-related protein (ADRP) in podocytes, and the extent of lipid deposition could be alleviated by losartan. Our study also demonstrated that Ang II increased the content of cholesterol in podocytes, which is an LD component, and this change was accompanied by decreased expression of the cholesterol efflux-related molecule ATP-binding cassette transporter-1 (ABCA1) and increased expression of the cholesterol uptake-related molecule LDL receptor (LDLR) and the cholesterol synthesis-related molecules sterol regulatory element-binding protein (SREBP1 and SREBP2) and 3-hydroxy-3-methylglutaryl CoA reductase (HMGCR). Pretreating podocytes with methyl-β-cyclodextrin (CD), which induces cholesterol efflux, decreased Ang II-mediated cholesterol accumulation and Ang II-induced podocyte apoptosis and maintained the podocyte cytoskeleton and spreading. These results suggested that Ang II induced podocyte cholesterol accumulation by regulating the expression of cholesterol metabolism-related molecules and that the subsequent cholesterol metabolism dysfunction resulted in podocyte injury.
| S-EPMC5587570 | biostudies-literature
Project description:Angiotensin II (Ang-II) is one of the major contributors to the progression of renal fibrosis, inflammation, glomerular injury, and chronic kidney disease. Emerging evidence suggests that renal glycolysis plays an important role in renal fibrosis and injury. TP53-induced glycolysis and apoptosis regulator (TIGAR) has been shown to regulate glycolysis. In the present study, we investigated the role of TIGAR in renal glycolysis, fibrosis, and glomerular injury during Ang-II-induced hypertension. Wild-type (WT) and TIGAR knockout (KO) mice were infused with Ang-II (1 µg/kg/min) via mini-pumps for 4 weeks. The mean arterial pressure was similar between the WT and TIGAR KO mice, associated with a comparable increase in plasma creatinine level. Ang-II infusion resulted in a significant increase in renal interstitial fibrosis and more mesangial expansion and collapsed glomerular structure in the TIGAR KO mice. These were associated with elevated expression of hypoxia-inducible factor-1 alpha, glycolytic enzymes, and transforming growth factor beta 1 in the TIGAR KO mice after Ang-II infusion when compared to that of the WT mice. The coupled-enzyme method revealed that PFK-1 activity was similarly increased in WT and TIGAR KO mice after Ang-II infusion. Our present study suggests that TIGAR is involved in Ang-II-induced renal fibrosis and glomerular injury, although it has little effect on blood pressure and renal function. Knockout of TIGAR sensitizes Ang-II-induced renal fibrosis and injury. This study provides new insights into the role of TIGAR in renal metabolism and pathological remodeling during Ang-II-induced hypertension.
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Project description:The endothelin system may be an important player in hypertensive end-organ injury as endothelin-1 increases blood pressure and is pro-inflammatory. The immune system is emerging as an important regulator of blood pressure and we have shown that the early hypertensive response to angiotensin-II infusion was amplified in mice deficient of myeloid endothelin-B (ETB) receptors (LysM-CreEdnrblox/lox). Hypothesizing that these mice would display enhanced organ injury, we gave angiotensin-II to LysM-CreEdnrblox/lox and littermate controls (Ednrblox/lox) for six weeks. Unexpectedly, LysM-CreEdnrblox/lox mice were significantly protected from organ injury, with less proteinuria, glomerulosclerosis and inflammation of the kidney compared to controls. In the eye, LysM-CreEdnrblox/lox mice had fewer retinal hemorrhages, less microglial activation and less vessel rarefaction. Cardiac remodeling and dysfunction were similar in both groups at week six but LysM-CreEdnrblox/lox mice had better endothelial function. Although blood pressure was initially higher in LysM-CreEdnrblox/lox mice, this was not sustained. A natriuretic switch at about two weeks, due to enhanced ETB signaling in the kidney, induced a hypertensive reversal. By week six, blood pressure was lower in LysM-CreEdnrblox/lox mice than in controls. At six weeks, macrophages from LysM-CreEdnrblox/lox mice were more anti-inflammatory and had greater phagocytic ability compared to the macrophages of Ednrblox/lox mice. Thus, myeloid cell ETB receptor signaling drives this injury both through amplifying hypertension and by inflammatory polarization of macrophages.
| S-EPMC7652550 | biostudies-literature
Project description:Angiotensin II can cause oxidative stress and increased blood pressure that result in long term cardiovascular pathologies. Here we evaluated the contribution of cellular senescence to the effect of chronic exposure to low dose angiotensin II in a model that mimics long term tissue damage. We utilized the INK-ATTAC (p16Ink4a-Apoptosis Through Targeted Activation of Caspase 8) transgenic mouse model that allows for conditional elimination of p16Ink4a -dependent senescent cells by administration of AP20187. Angiotensin II treatment for 3 weeks induced ATTAC transgene expression in kidneys but not in lung, spleen and brain tissues. In the kidneys increased expression of ATM, p15 and p21 matched with angiotensin II induction of senescence-associated secretory phenotype genes MMP3, FGF2, IGFBP2, and tPA. Senescent cells in the kidneys were identified as endothelial cells by detection of GFP expressed from the ATTAC transgene and increased expression of angiopoietin 2 and von Willebrand Factor, indicative of endothelial cell damage. Furthermore, angiotensin II induced expression of the inflammation-related glycoprotein versican and immune cell recruitment to the kidneys. AP20187-mediated elimination of p16-dependent senescent cells prevented physiologic, cellular and molecular responses to angiotensin II and provides mechanistic evidence of cellular senescence as a driver of angiotensin II effects.
| S-EPMC8696590 | biostudies-literature
Project description:UNLABELLED:Activation of the renin angiotensin system resulting in stimulation of angiotensin-II (AngII) type I receptor (AT1R) is an important factor in the development of liver fibrosis. Here, we investigated the role of Janus kinase 2 (JAK2) as a newly described intracellular effector of AT1R in mediating liver fibrosis. Fibrotic liver samples from rodents and humans were compared to respective controls. Transcription, protein expression, activation, and localization of JAK2 and downstream effectors were analyzed by real-time polymerase chain reaction, western blotting, immunohistochemistry, and confocal microscopy. Experimental fibrosis was induced by bile duct ligation (BDL), CCl4 intoxication, thioacetamide intoxication or continuous AngII infusion. JAK2 was inhibited by AG490. In vitro experiments were performed with primary rodent hepatic stellate cells (HSCs), Kupffer cells (KCs), and hepatocytes as well as primary human and human-derived LX2 cells. JAK2 expression and activity were increased in experimental rodent and human liver fibrosis, specifically in myofibroblastic HSCs. AT1R stimulation in wild-type animals led to activation of HSCs and fibrosis in vivo through phosphorylation of JAK2 and subsequent RhoA/Rho-kinase activation. These effects were prevented in AT1R(-/-) mice. Pharmacological inhibition of JAK2 attenuated liver fibrosis in rodent fibrosis models. In vitro, JAK2 and downstream effectors showed increased expression and activation in activated HSCs, when compared to quiescent HSCs, KCs, and hepatocytes isolated from rodents. In primary human and LX2 cells, AG490 blocked AngII-induced profibrotic gene expression. Overexpression of JAK2 led to increased profibrotic gene expression in LX2 cells, which was blocked by AG490. CONCLUSION:Our study substantiates the important cell-intrinsic role of JAK2 in HSCs for development of liver fibrosis. Inhibition of JAK2 might therefore offer a promising therapy for liver fibrosis.
| S-EPMC5512562 | biostudies-literature
Project description:Malaria-induced acute kidney injury (MAKI) is a life-threatening complication of severe malaria. Here, we investigated the potential role of the angiotensin II (Ang II)/AT1 receptor pathway in the development of MAKI. We used C57BL/6 mice infected by Plasmodium berghei ANKA (PbA-infected mice), a well-known murine model of severe malaria. The animals were treated with 20 mg/kg/day losartan, an antagonist of AT1 receptor, or captopril, an angiotensin-converting enzyme inhibitor. We observed an increase in the levels of plasma creatinine and blood urea nitrogen associated with a significant decrease in creatinine clearance, a marker of glomerular flow rate, and glomerular hypercellularity, indicating glomerular injury. PbA-infected mice also presented proteinuria and a high level of urinary ?-glutamyltransferase activity associated with an increase in collagen deposition and interstitial space, showing tubule-interstitial injury. PbA-infected mice were also found to have increased fractional excretion of sodium (FENa+) coupled with decreased cortical (Na++K+)ATPase activity. These injuries were associated with an increase in pro-inflammatory cytokines, such as tumor necrosis factor alpha, interleukin-6, interleukin-17, and interferon gamma, in the renal cortex of PbA-infected mice. All modifications of these structural, biochemical, and functional parameters observed in PbA-infected mice were avoided with simultaneous treatment with losartan or captopril. Our data allow us to postulate that the Ang II/AT1 receptor pathway mediates an increase in renal pro-inflammatory cytokines, which in turn leads to the glomerular and tubular injuries observed in MAKI.
| S-EPMC6133374 | biostudies-literature
Project description:ObjectiveRecent studies have shown that angiotensin II (Ang II) plays a critical role in the pathogenesis and progression of hypertensive kidney disease. However, the signaling mechanisms are poorly understood. In this study, we investigated the role of CXCR6 in Ang II-induced renal injury and fibrosis.Approach and resultsWild-type and CXCR6-green fluorescent protein (GFP) knockin mice were treated with Ang II via subcutaneous osmotic minipumps at 1500 ng/kg per minute after unilateral nephrectomy for ≤ 4 weeks. Wild-type and CXCR6-GFP knockin mice had virtually identical blood pressure at baseline. Ang II treatment led to an increase in blood pressure that was similar between wild-type and CXCR6-GFP knockin mice. CXCR6-GFP knockin mice were protected from Ang II-induced renal dysfunction, proteinuria, and fibrosis. CXCR6-GFP knockin mice accumulated fewer bone marrow-derived fibroblasts and myofibroblasts and produced less extracellular matrix protein in the kidneys after Ang II treatment. Furthermore, CXCR6-GFP knockin mice exhibited fewer F4/80(+) macrophages and CD3(+) T cells and expressed less proinflammatory cytokines in the kidneys after Ang II treatment. Finally, wild-type mice engrafted with CXCR6(-/-) bone marrow cells displayed fewer bone marrow-derived fibroblasts, macrophages, and T cells in the kidney after Ang II treatment when compared with wild-type mice engrafted with CXCR6(+/+) bone marrow cells.ConclusionsOur results indicate that CXCR6 plays a pivotal role in the development of Ang II-induced renal injury and fibrosis through regulation of macrophage and T-cell infiltration and bone marrow-derived fibroblast accumulation.
| S-EPMC4089979 | biostudies-literature
Project description:Here we evaluated the contribution of cellular senescence to the effect of chronic exposure to low dose angiotensin II in a mouse model that mimics the initiation of hypertension. We utilized the INK-ATTAC (p16ink4a - Apoptosis Through Targeted Activation of Caspase 8) mouse model that allows for conditional elimination of p16ink4a -dependent senescent cells by administration of AP20187. INK-ATTAC mice received continuous low doses of angiotensin II over 3 weeks and AP20187 vs vehicle. In the kidneys increased expression of ATM, p15 and p21 matched with angiotensin II induction of senescence-associated secretory phenotype genes MMP3, FGF2, IGFBP2, and tPA. AP20187-mediated elimination of p16-dependent senescent cells prevented physiologic, cellular and molecular responses to angiotensin II. We conclude that angiotensin II induces a relatively selective senescence transformation of renal endothelial cells that could provide a novel therapeutic target for senolytic drugs as alternative treatment options for hypertension and resulting tissue damage.
2022-01-10 | GSE179195 | GEO
Project description:Experiments with hyperaldosteronemic animals suggest that, despite lowering plasma aldosterone, salt worsens renal injury by paradoxical activation of the mineralocorticoid receptor (MR). Salt and aldosterone synergistically contribute to renal impairment through Rac1-mediated activation of the MR, but whether angiotensin II also promotes renal injury through this mechanism is unknown. Here, we placed angiotensin II-overproducing double transgenic Tsukuba hypertensive mice on a low- or high-salt intake for 6 weeks and treated some animals with adrenalectomy, the MR antagonist eplerenone, the Rac inhibitor EHT1864, or hydralazine. High-salt intake, but not low-salt intake, led to hypertension and prominent kidney injury. Adrenalectomy prevented angiotensin II/salt-induced nephropathy in mice receiving high-salt intake, which was recapitulated by aldosterone supplementation, suggesting the involvement of aldosterone/MR signaling. Plasma aldosterone levels, however, were lower in high- than low-salt conditions. Instead, angiotensin II/salt-evoked MR activation associated with Rac1 activation and was not dependent on plasma aldosterone level. Both EHT1864 and eplerenone repressed the augmented MR signaling and mitigated kidney injury with partial but significant reduction in BP with high-salt intake. Hydralazine similarly reduced BP, but it neither suppressed the Rac1-MR pathway nor ameliorated the nephropathy. Taken together, these results show that angiotensin II and salt accelerate kidney injury through Rac1-mediated MR activation. Rac inhibition may be a promising strategy for the treatment of CKD.
| S-EPMC3358757 | biostudies-literature
Project description:Kidneys are pivotal organ in iron redistribution and can be severely damaged in the course of hemolysis. In our previous studies, we observed that induction of hyper- tension with angiotensin II (Ang II) combined with simvastatin administration results in a high mortality rate or the appearance of signs of kidney failure in heme oxy- genase-1 knockout (HO-1 KO) mice. Here, we aimed to address the mechanisms underlying this effect, focusing on heme and iron metabolism. We show that HO-1 deficiency leads to iron accumulation in the renal cortex. Higher mortality of Ang II and simvastatin-treated HO-1 KO mice coincides with in- creased iron accumulation and the upregulation of mucin-1 in the proximal convoluted tubules. In vitro studies showed that mucin-1 hampers heme- and iron-related oxidative stress through the sialic acid residues. In parallel, knock-down of HO-1 induces the glutathione pathway in an NRF2-depedent manner, which likely protects against heme-induced toxicity. To sum up, we showed that heme degradation during heme overload is not solely dependent on HO-1 enzymatic activity, but can be modulated by the glutathione pathway. We also identified mucin-1 as a novel redox regulator. The results suggest that hypertensive patients with less active HMOX1 alleles may be at higher risk of kidney injury after statin treatment.
2023-06-19 | PXD042995 | Pride