Faculty Opinions recommendation of Origin of interstitial fibroblasts in an accelerated model of angiotensin II-induced renal fibrosis.

Author(s):  
Frank Strutz
2001 ◽  
Vol 280 (5) ◽  
pp. F777-F785 ◽  
Author(s):  
Guangjie Guo ◽  
Jeremiah Morrissey ◽  
Ruth McCracken ◽  
Timothy Tolley ◽  
Helen Liapis ◽  
...  

Angiotensin II upregulates tumor necrosis factor-α (TNF-α) in the rat kidney with unilateral ureteral obstruction (UUO). In a mouse model of UUO, we found that tubulointerstitial fibrosis is blunted when the TNF-α receptor, TNFR1, is functionally knocked out. In this study, we used mutant mice with UUO in which the angiotensin II receptor AT1a or the TNF-α receptors TNFR1 and TNFR2 were knocked out to elucidate interactions between the two systems. The contribution of both systems to renal fibrosis was assessed by treating TNFR1/TNFR2-double knockout (KO) mice with an angiotensin-converting enzyme inhibitor, enalapril. The increased interstitial volume (Vvint) in the C57BI/6 wild-type mouse was decreased in the AT1a KO from 32.8 ± 4.0 to 21.0 ± 3.7% ( P < 0.005) or in the TNFR1/TNFR2 KO to 22.3 ± 2.1% ( P < 0.005). The Vvint of the TNFR1/TNFR2 KO was further decreased to 15.2 ± 3.7% ( P < 0.01) by enalapril compared with no treatment. The induction of TNF-α mRNA and transforming growth factor-β1 (TGF-β1) mRNA in the kidney with UUO was significantly blunted in the AT1a or TNFR1/TNFR2 KO mice compared with the wild-type mice. Treatment of the TNFR1/TNFR2 KO mouse with enalapril reduced both TNF-α and TGF-β1 mRNA and their proteins to near normal levels. Also, α-smooth muscle actin expression and myofibroblast proliferation were significantly inhibited in the AT1a or TNFR1/TNFR2 KO mice, and they were further inhibited in enalapril-treated TNFR1/TNFR2 KO mice. Incapacitating the angiotensin II or the TNF-α systems individually leads to partial blunting of fibrosis. Incapacitating both systems, by using a combination of genetic and pharmacological means, further inhibited interstitial fibrosis and tubule atrophy in obstructive nephropathy.


2016 ◽  
Vol 789 ◽  
pp. 421-430 ◽  
Author(s):  
Melissa Skibba ◽  
Yuanyuan Qian ◽  
Yuyan Bao ◽  
Junjie Lan ◽  
Kesong Peng ◽  
...  

Hypertension ◽  
2020 ◽  
Vol 76 (6) ◽  
pp. 1906-1914
Author(s):  
Yoshiki Aibara ◽  
Ayumu Nakashima ◽  
Ki-ichiro Kawano ◽  
Farina Mohamad Yusoff ◽  
Fumitaka Mizuki ◽  
...  

The estimated morbidity rate of chronic kidney disease is 8% to 16% worldwide, and many patients with chronic kidney disease eventually develop renal failure. Thus, the development of new therapeutic strategies for preventing renal failure is crucial. In this study, we assessed the effects of daily low-intensity pulsed ultrasound (LIPUS) therapy on experimental hypertensive nephropathy and diabetic nephropathy. Unilateral nephrectomy and subcutaneous infusion of angiotensin II via osmotic mini-pumps were used to induce hypertensive nephropathy in mice. Immunohistochemistry revealed that daily LIPUS treatment ameliorated renal fibrosis and infiltration of inflammatory cells induced by angiotensin II. A similar therapeutic effect was also observed in mice with angiotensin II-induced hypertensive nephropathy in which splenectomy was performed. In addition, LIPUS treatment significantly decreased systolic blood pressure after 21 days. Subsequently, db/db mice with unilateral nephrectomy developed proteinuria; daily LIPUS treatment significantly reduced proteinuria after 42 days. In addition, immunohistochemistry revealed that renal fibrosis was significantly ameliorated by LIPUS treatment. Finally, LIPUS stimulation suppressed TGF-β1 (transforming growth factor-β1)-induced phosphorylation of Smad2 and Smad3 in HK-2 (human proximal tubular cell line) cells. LIPUS treatment may be a useful therapy for preventing the progression of renal fibrosis in patients with chronic kidney disease.


2020 ◽  
Vol 51 (2) ◽  
pp. 119-129 ◽  
Author(s):  
Giovanna Castoldi ◽  
Raffaella Carletti ◽  
Silvia Ippolito ◽  
Massimiliano Colzani ◽  
Francesca Barzaghi ◽  
...  

Background: Clinical trials have shown that empagliflozin (Empa), a sodium-glucose cotransporter 2 (SGLT2) inhibitor, promotes nephroprotective effects in diabetic patients. The mechanisms underlying nephroprotection are not completely known and it is not known whether the renal beneficial action is present even in non-diabetic kidney disease. The aim of this study was to evaluate the effect of Empa administration on the development of renal fibrosis in an experimental model of angiotensin II (Ang II)-dependent hypertension. Methods: Sprague Dawley rats (n = 31) were divided into 4 experimental groups. Ang II (200 ng/kg/min, osmotic minipumps, s.c., n = 9) or Ang II + Empa (10 mg/kg/day, per os, n = 10) were administered for 2 weeks. Control rats were treated with placebo (physiological saline, n = 6), and another group was treated with placebo plus Empa (n = 6) for the same period. Blood pressure (plethysmographic method) was measured at the beginning and at the end of the experimental protocol. After 2 weeks, the rats were euthanized and the kidneys were excised for histomorphometric evaluation of glomerular and tubulo-interstitial fibrosis and for the immunohistochemical evaluation of inflammatory infiltrates (monocytes/macrophages) and types I and IV collagen expression. Results: The administration of Ang II resulted in an increase in blood pressure (p < 0.01), glomerular (p < 0.05) and tubulo-interstitial (p < 0.01) fibrosis, renal inflammatory infiltrates (p < 0.01) and type I (p < 0.01) and type IV collagen expression (p < 0.05) compared to the control group. Treatment with Empa did not significantly modify the increase in blood pressure due to Ang II, but prevented the development of renal glomerular and tubulo-interstitial fibrosis, and the increase in inflammatory infiltrates and types I and IV collagen expression in Ang II-treated rats (p < 0.01). Conclusions: These data demonstrate that the treatment with Empa prevents the development of renal fibrosis in Ang II-dependent hypertension. In Ang II-dependent hypertension, the anti-fibrotic effect due to SGLT2 inhibition is caused by the reduction of inflammatory infiltrates and it is independent on the modulation of blood pressure increase.


2013 ◽  
Vol 304 (6) ◽  
pp. F686-F697 ◽  
Author(s):  
Jang Han Lee ◽  
Ji Hyun Kim ◽  
Ja Seon Kim ◽  
Jai Won Chang ◽  
Soon Bae Kim ◽  
...  

The epithelial-mesenchymal transition (EMT) is a novel mechanism that promotes renal fibrosis. Transforming growth factor-β (TGF-β), angiotensin II, aldosterone, high glucose, and urinary albumin are well-known causes of EMT and renal fibrosis. We examined whether and how activation of AMP-activated protein kinase (AMPK) suppressed EMT induced by the above agents in tubular epithelial cells. All experiments were performed using HK-2 cells. Protein expression was measured by Western blot analysis. Intracellular reactive oxygen species (ROS) were analyzed by flow cytometry. Exposure of tubular cells to TGF-β (10 ng/ml), angiotensin II (1 μM), aldosterone (100 nM), high glucose (30 mM), and albumin (5 mg/ml) for 5 days induced EMT, as shown by upregulation of α-smooth muscle actin and downregulation of E-cadherin. ROS and NADPH oxidase 4 (Nox4) expression were increased, and antioxidants such as tiron and N-acetylcysteine inhibited EMT induction. Metformin (the best known clinical activator of AMPK) suppressed EMT induction through inhibition of ROS via induction of heme oxygenase-1 and endogenous antioxidant thioredoxin. An AMPK inhibitor (compound C) and AMPK small interfering RNA blocked the effect of metformin, and another AMPK activator [5-aminoimidazole-4-carboxamide-1β riboside (AICAR)] exerted the same effects as metformin. In conclusion, AMPK activation might be beneficial in attenuating the tubulointerstitial fibrosis induced by TGF-β, angiotensin II, aldosterone, high glucose, and urinary albumin.


2002 ◽  
Vol 110 (12) ◽  
pp. 1859-1868 ◽  
Author(s):  
Masashi Nishida ◽  
Hidehiko Fujinaka ◽  
Taiji Matsusaka ◽  
James Price ◽  
Valentina Kon ◽  
...  

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Kazuma Iekushi ◽  
Yoshiaki Taniyama ◽  
Junya Azuma ◽  
Fumihiro Sanada ◽  
Norio Dosaka ◽  
...  

Progression of chronic kidney disease (CKD) is characterized by the persistent accumulation of extracellular matrix. Especially, α-SMA positive myofibroblast which produce high amounts of TGF-β1 are considered to play a key role in interstitial fibrosis. Previous studies demonstrated that hepatocyte growth factor (HGF) improved kidney fibrosis in murine models, where direct molecular mechanisms of myofibroblasts have not yet been understood. We tested the hypothesis in vivo using cardiac specific overexpression HGF mice (HGF-Tg), which showed a significant increase in serum HGF concentration. Angiotensin II (Ang II) infusion significantly induced renal fibrosis in wild type mice, while renal fibrosis was significantly decreased in HGF-Tg mice accompanied by the degrease in interstitial myofibroblasts (P<0.05). Quantitative analysis demonstrated 1.69-folds induction of profibrtic cytokine, TGF-β1 mRNA in HGF-Tg with Ang II group compared with wild type with Ang II, and Collagen type I and IV mRNA expression was significantly decreased in HGF-Tg mice with Ang II. The antifibotic action of HGF-Tg mice was concordant with an increase in MMP-2, MMP-9 expression (1.32-fold, 1.33-fold vs wild type with Ang II infusion, P<0.05, respectively), and decreased TIMP-1, TIMP-2 expression (1.5-fold, 1.28-fold vs wild type with Ang II infusion, P<0.05, respectively). To further investigate the anti-fibrotic effect of HGF, we used cultured human mesangial cells (HMC). When HMC were treated with TGF-β1, cells underwent to phenotypic change similar to myofibroblasts, accompanied by the significant increase in c-Met/HGF receptor (P<0.05). Under such conditions, HGF induced anoikis-induced apoptosis of myofibroblasts. It also linked with FAK phosphorylation especially p-FAK (Y925) (P<0.05). When GM6001 (a broad-spectrum MMP inhibitor) was added with HGF, HGF-induced apptosis was significantly decreased. It was suggested that increased activities of MMPs underlie the major mechanism of HGF mediated anoikis induced apoptosis. The present study demonstrated that HGF elicited myofibroblast anoikis. Activation of MMPs in fibrotic kidney might be considered as a target to attenuate the progression of CKD.


2015 ◽  
Vol 117 (suppl_1) ◽  
Author(s):  
Magdalena Mayr ◽  
Clemens Duerrschmid ◽  
Dorellyn B Lee ◽  
Guillermo Medrano ◽  
George E Taffet ◽  
...  

Background: Brief systemic infusion of Angiotensin-II (Ang-II) to wild-type (WT) mice initiates the development of cardiac interstitial fibrosis. Genetic deletion of tumor necrosis factor receptor 1 (TNFR1) obviates this development and concurrently inhibits Ang-II-induced cardiac remodeling and dysfunction. We now investigated long-term effects of Ang-II on the heart, kidney, and cardiorenal function. Methods: WT and TNFR1-KO mice were infused with 1.5 ug/kg/min Ang-II for 1 and 6 weeks (no uninephrectomy or high-salt diet). Heart, kidney, and serum were isolated and evaluated by histology, cytometry, qPCR, and ELISA techniques. Cardiac function was determined by 2D-echocardiography, systolic blood pressure by tail-cuff plethysmography. Results: Brief infusion of Ang-II to WT mice did not evoke a fibrotic response in the kidney. However, after 6 weeks, WT kidneys developed minimal, but significant interstitial collagen deposition which was supported by upregulation of collagen-I, collagen-III, and alpha-smooth muscle actin gene activation. This fibrotic development was associated with the appearance of myeloid fibroblast precursors, pro-inflammatory M1 and pro-fibrotic M2 cells, and myofibroblasts. Transcriptional expression of pro-inflammatory and pro-fibrotic genes was also increased. These changes were not seen in Ang-II-infused TNFR1-KO kidneys. In WT hearts, despite the disappearance of myeloid cells, cardiac fibrosis persisted throughout the 6-week infusion. WT hearts developed clear evidence of accelerated cardiac hypertrophy and remodeling associated with impaired systolic function. Again, these changes were not seen in Ang-II-infused TNFR1-KO hearts. By contrast, both WT and TNFR1-KO mice responded identically with similar elevations of systolic blood pressure, and serum blood urea nitrogen and creatinine levels. Conclusions: Ang-II-infusion induced an immediate fibrotic response in the heart while fibrosis in the kidney developed slowly. The cardiac fibrosis was accompanied by progressive adverse remodeling and worsening of function over time. TNFR1-KO mice were protected from the Ang-II-induced cardiac and renal fibrosis, despite similar increases in blood pressure and renal dysfunction.


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