scholarly journals Deficiency of mPGES-1 exacerbates renal fibrosis and inflammation in mice with unilateral ureteral obstruction

2017 ◽  
Vol 312 (1) ◽  
pp. F121-F133 ◽  
Author(s):  
Renfei Luo ◽  
Yutaka Kakizoe ◽  
Feifei Wang ◽  
Xiang Fan ◽  
Shan Hu ◽  
...  

Microsomal prostaglandin E2 synthase-1 (mPGES-1), an inducible enzyme that converts prostaglandin H2 to prostaglandin E2 (PGE2), plays an important role in a variety of inflammatory diseases. We investigated the contribution of mPGES-1 to renal fibrosis and inflammation in unilateral ureteral obstruction (UUO) for 7 days using wild-type (WT) and mPGES-1 knockout (KO) mice. UUO induced increased mRNA and protein expression of mPGES-1 and cyclooxygenase-2 in WT mice. UUO was associated with increased renal PGE2 content and upregulated PGE2 receptor (EP) 4 expression in obstructed kidneys of both WT and mPGES-1 KO mice; EP4 expression levels were higher in KO mice with UUO than those in WT mice. Protein expression of NLRP3 inflammasome components ASC and interleukin-1β was significantly increased in obstructed kidneys of KO mice compared with that in WT mice. mRNA expression levels of fibronectin, collagen III, and transforming growth factor-β1 (TGF-β1) were significantly higher in obstructed kidneys of KO mice than that in WT mice. In KO mice, protein expression of fibronectin and collagen III was markedly increased in obstructed kidneys compared with WT mice, which was associated with increased phosphorylation of protein kinase B (AKT). EP4 agonist CAY10598 attenuated increased expression of collagen I and fibronectin induced by TGF-β1 in inner medullary collecting duct 3 cells. Moreover, CAY10598 prevented the activation of NLRP3 inflammasomes induced by angiotensin II in human proximal tubule cells (HK2). In conclusion, these findings suggested that mPGES-1 exerts a potentially protective effect against renal fibrosis and inflammation induced by UUO in mice.

2011 ◽  
Vol 301 (2) ◽  
pp. F450-F459 ◽  
Author(s):  
Jinu Kim ◽  
Babu J. Padanilam

Poly(ADP-ribose) polymerase 1 (PARP1) contributes to necrotic cell death and inflammation in several disease models; however, the role of PARP1 in fibrogenesis remains to be defined. Here, we tested whether PARP1 was involved in the pathogenesis of renal fibrosis using the unilateral ureteral obstruction (UUO) mouse model. UUO was performed by ligation of the left ureter near the renal pelvis in Parp1-knockout (KO) and wild-type (WT) male mice. After 10 days of UUO, renal PARP1 expression and activation were strongly increased by 6- and 13-fold, respectively. Interstitial fibrosis induced by UUO was significantly attenuated in Parp1-KO kidneys compared with that in WT kidneys at 10 days, but not at 3 days, based on collagen deposition, α-smooth muscle actin (α-SMA), and fibronectin expression. Intriguingly, the UUO kidneys in Parp1-KO mice showed a dramatic decrease in infiltration of neutrophil and reduction in expression of proinflammatory proteins including intercellular adhesion molecule-1, tumor necrosis factor-α, inducible nitric oxide synthase, and toll-like receptor 4 as well as phosphorylation of nuclear factor-κB p65, but not transforming growth factor-β1 (TGF-β1) at both 3 and 10 days. Pharmacological inhibition of PARP1 in rat renal interstitial fibroblast (NRK-49F) cell line or genetic ablation in primary mouse embryonic fibroblast cells did not affect TGF-β1-induced de novo α-SMA expression. Parp1 deficiency significantly attenuated UUO-induced histological damage in the kidney tubular cells, but not apoptosis. These data suggest that PARP1 induces necrotic cell death and contributes to inflammatory signaling pathways that trigger fibrogenesis in obstructive nephropathy.


Endocrinology ◽  
2009 ◽  
Vol 150 (2) ◽  
pp. 727-740 ◽  
Author(s):  
Yu-Lin Yang ◽  
Yi-Shiuan Liu ◽  
Lea-Yea Chuang ◽  
Jinn-Yuh Guh ◽  
Tao-Chen Lee ◽  
...  

TGF-β is a therapeutic target for renal fibrosis. Scientists have long sought ways to antagonize TGF-β to ameliorate diabetic nephropathy. Bone morphogenetic protein (BMP-2) is a member of the TGF-β superfamily and is highly regulated in the kidney. Thus, the role of BMP-2 was investigated in NRK-49F cells (rat fibroblasts). We showed that TGF-β1 induces an increase in fibronectin. Treatment with exogenous BMP-2 or pCMV-BMP-2 significantly reversed the TGF-β1-induced increase in fibronectin concomitant with a significant decrease in type I TGF-β receptors (TGF-β RI). Moreover, BMP-2 significantly shortened the half-life of TGF-β RI. These results are related to proteosomal activation because MG132, a proteasome inhibitor, abolished BMP-2-mediated degradation of TGF-β RI. This was confirmed because BMP-2 time course dependently enhanced the ubiquitination level of TGF-β RI. In addition, Smads would seem to be involved in the interaction of BMP-2 and TGF-β. We demonstrated that BMP-2 significantly reversed the TGF-β1-induced increase in pSmad2/3 and reversed the TGF-β1-induced decrease in inhibitory Smad7. Most importantly, Smad7 small interfering RNA abolished the BMP-2-induced decrease in TGF-β RI. We evaluated the clinical efficacy of BMP-2 using unilateral ureteral obstruction rats. BMP-2 was administered ip for 7 d. In the unilateral ureteral obstruction kidneys, interstitial fibrosis was prominent. However, treatment with BMP-2 dramatically reduced Masson’s trichrome staining (collagen) in the interstitial and tubular areas of the kidneys concomitantly with a reduction in TGF-β RI. These results suggest that BMP-2 acts as a novel fibrosis antagonizing cytokine partly by down-regulating TGF-β RI and Smads. Bone morphogenetic protein-2 can antagonize TGF-β-inducing cellular fibrosis by intervening post-receptors signaling, thus disclosing an application of therapeutical potential against fibrosis disorders.


2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Dapeng Zhao ◽  
Zhongqiu Luan

Renal fibrosis is a common final pathological process in the progression of kidney disease. Oleanolic acid is a bioactive pentacyclic triterpenoid and is widely found in medicinal herbs around the world. In this study, we explored the effect of oleanolic acid on renal fibrosis and the underlying molecular mechanisms by using a rat model of unilateral ureteral obstruction (UUO). Male Sprague-Dawley rats were orally administered with oleanolic acid (6 mg/kg/d) or vehicle (olive oil) for 21 days after the UUO surgery. Upon termination, urine and blood were collected for renal function analysis, and kidneys were harvested for pathological analysis by using hematoxylin-eosin and Masson trichrome staining. Changes of extracellular matrix mRNA expressions and TGF-β/Smad signaling in the kidneys were also determined. As a result, oleanolic acid significantly reduced the kidney index, the level of serum creatinine and blood urea nitrogen, and the urinary level of microalbumin, α1-microglobulin, and N-acetyl-β-glucosaminidase. Masson trichrome staining showed significantly less collagen deposition in the UUO rats with oleanolic acid treatment. Diminished mRNA expressions of collagen I, collagen III, fibronectin, and α-SMA in the kidney tissues were observed after the treatment. Oleanolic acid led to decreased protein expressions of TGF-β, TGF-β receptor I, and TGF-β receptor II, as well as the phosphorylation of Smad2. Our current study suggested that oleanolic acid could be a complementary and alternative therapy for renal fibrosis potentially by targeting the TGF-β/Smad pathway.


2020 ◽  
Vol 21 (2) ◽  
pp. 402 ◽  
Author(s):  
Yi Quan ◽  
Woong Park ◽  
Jixiu Jin ◽  
Won Kim ◽  
Sung Kwang Park ◽  
...  

Renal fibrosis is a common feature of all progressive chronic kidney diseases. Sirtuin 3 (SIRT3) is one of the mitochondrial sirtuins, and plays a role in the regulation of mitochondrial biogenesis, oxidative stress, fatty acid metabolism, and aging. Recently, honokiol (HKL), as a pharmaceutical SIRT3 activator, has been observed to have a protective effect against pressure overload-induced cardiac hypertrophy by increasing SIRT3 activity. In this study, we investigated whether HKL, as a SIRT3 activator, also has protective effects against unilateral ureteral obstruction (UUO)-induced renal tubulointerstitial fibrosis through SIRT3-dependent regulation of mitochondrial dynamics and the nuclear factor-κB (NF-κB)/transforming growth factor-β1 (TGF-β1)/Smad signaling pathway. We found that HKL decreased the UUO-induced increase in tubular injury and extracellular matrix (ECM) deposition in mice. HKL also decreased myofibroblast activation and proliferation in UUO kidneys and NRK-49F cells. Finally, we showed that HKL treatment decreased UUO-induced mitochondrial fission and promoted mitochondrial fusion through SIRT3-dependent effects. In conclusion, activation of SIRT3 via HKL treatment might have beneficial effects on UUO-induced renal fibrosis through SIRT3-dependent regulation of mitochondrial dynamics and the NF-κB/TGF-β1/Smad signaling pathway.


2013 ◽  
Vol 305 (5) ◽  
pp. F618-F627 ◽  
Author(s):  
Shenyang Li ◽  
Nithya Mariappan ◽  
Judit Megyesi ◽  
Brian Shank ◽  
Krishnaswamy Kannan ◽  
...  

We examined the effects of increased expression of proximal tubule peroxisome proliferator-activated receptor (PPAR)α in a mouse model of renal fibrosis. After 5 days of unilateral ureteral obstruction (UUO), PPARα expression was significantly reduced in kidney tissue of wild-type mice but this downregulation was attenuated in proximal tubules of PPARα transgenic (Tg) mice. When compared with wild-type mice subjected to UUO, PPARα Tg mice had reduced mRNA and protein expression of proximal tubule transforming growth factor (TGF)-β1, with reduced production of extracellular matrix proteins including collagen 1, fibronectin, α-smooth muscle actin, and reduced tubulointerstitial fibrosis. UUO-mediated increased expression of microRNA 21 in kidney tissue was also reduced in PPARα Tg mice. Overexpression of PPARα in cultured proximal tubular cells by adenoviral transduction reduced aristolochic acid-mediated increased production of TGF-β, demonstrating PPARα signaling reduces epithelial TGF-β production. Flow cytometry studies of dissociated whole kidneys demonstrated reduced macrophage infiltration to kidney tissue in PPARα Tg mice after UUO. Increased expression of proinflammatory cytokines including IL-1β, IL-6, and TNF-α in wild-type mice was also significantly reduced in kidney tissue of PPARα Tg mice. In contrast, the expression of anti-inflammatory cytokines IL-10 and arginase-1 was significantly increased in kidney tissue of PPARα Tg mice when compared with wild-type mice subjected to UUO. Our studies demonstrate several mechanisms by which preserved expression of proximal tubule PPARα reduces tubulointerstitial fibrosis and inflammation associated with obstructive uropathy.


2016 ◽  
Vol 311 (3) ◽  
pp. F614-F625 ◽  
Author(s):  
Maria Mustafa ◽  
Tony N. Wang ◽  
Xing Chen ◽  
Bo Gao ◽  
Joan C. Krepinsky

Tubulointerstitial fibrosis is a major feature associated with declining kidney function in chronic kidney disease of diverse etiology. No effective means as yet exists to prevent the progression of fibrosis. We have shown that the transcription factor sterol-regulatory element-binding protein 1 (SREBP-1) is an important mediator of the profibrotic response to transforming growth factor-β (TGF-β) and angiotensin II, both key cytokines in the fibrotic process. Here, we examined the role of SREBP in renal interstitial fibrosis in the unilateral ureteral obstruction (UUO) model. The two isoforms of SREBP (-1 and -2) were activated by 3 days after UUO, with SREBP-1 showing a more sustained activation to 21 days. We then examined whether SREBP1/2 inhibition with the small-molecule inhibitor fatostatin could attenuate fibrosis after 14 days of UUO. SREBP activation was confirmed to be inhibited by fatostatin. Treatment decreased interstitial fibrosis, TGF-β signaling, and upregulation of α-smooth muscle actin (SMA), a marker of fibroblast activation. Fatostatin also attenuated inflammatory cell infiltrate and apoptosis. Associated with this, fatostatin preserved proximal tubular mass. The significant increase in atubular glomeruli observed after UUO, known to correlate with irreversible renal functional decline, was also decreased by treatment. In cultured primary fibroblasts, TGF-β1 induced the activation of SREBP-1 and -2. Fatostatin blocked TGF-β1-induced α-SMA and matrix protein upregulation. The inhibition of SREBP is thus a potential novel therapeutic target in the treatment of fibrosis in chronic kidney disease.


2010 ◽  
Vol 299 (6) ◽  
pp. F1486-F1495 ◽  
Author(s):  
Jesse M. Wolstein ◽  
David H. Lee ◽  
Jennine Michaud ◽  
Venessa Buot ◽  
Beth Stefanchik ◽  
...  

The INK4a proteins p16INK4a and p19ARF regulate cell cycle arrest and senescence. However, the role of these proteins in controlling these processes in the normal kidney and following injury is unknown. We performed unilateral ureteral obstruction (UUO) to induce fibrosis in 2- to 3-mo-old wild-type (WT) C57/B6 and INK4a knockout mice. By quantitative RT-PCR, p16INK4a levels were increased sixfold in WT mice 7 days after UUO and p19ARF remained undetectable. Kidney sections were examined to determine levels and localization of p16INK4a, apoptosis, fibrosis, and senescent cells. INK4a knockout mice displayed mesangial cell proliferation, increased matrix deposition, and myofibroblast differentiation under normal conditions. Following UUO, INK4a knockout mice displayed 10-fold increased tubular and interstitial cell proliferation, 75% decreased collecting duct apoptosis, 2-fold greater collagen and fibronectin deposition, and no cell senescence by senescence-associated β-galactosidase staining compared with WT mice. Both INK4a knockout mesangial cells and kidney lysates from knockout mice following injury showed elevated levels of IL-6 by ELISA compared with WT samples. INK4a knockout epithelial cell cultures displayed increased mesenchymal cell markers when exposed to transforming growth factor-β. These results confirm that p16INK4a controls cell proliferation and matrix production and mitigates fibrosis following injury and suggest that the mechanism involves a role in limiting inflammation and cell proliferation.


2018 ◽  
Vol 315 (4) ◽  
pp. F769-F780 ◽  
Author(s):  
Zheng Wang ◽  
Alex Divanyan ◽  
Frances L. Jourd’heuil ◽  
Robert D. Goldman ◽  
Karen M. Ridge ◽  
...  

Most renal transplants ultimately fail secondary to chronic allograft nephropathy (CAN). Vimentin (vim) is a member of the intermediate filament family of proteins and has been shown to be important in the development of CAN. One of the pathways leading to chronic renal fibrosis after transplant is thought to be epithelial to mesenchymal transition (EMT). Even though vim expression is one of the main steps of EMT, it is unknown whether vim expression is required for EMT leading to renal fibrosis and allograft loss. To this end, the role of vim in renal fibrosis was determined via unilateral ureteral obstruction (UUO) in vim knockout mice (129 svs6 vim −/−). Following UUO, kidneys were recovered and analyzed via Western blotting, immunofluorescence, and transcriptomics. Cultured human proximal renal tubular (HK-2) cells were subjected to lentiviral-driven inhibition of vim expression and then treated with transforming growth factor (TGF)-β to undergo EMT. Immunoblotting as well as wound healing assays were used to determine development of EMT. Western blotting analyses of mice undergoing UUO reveal increased levels of vim soon after UUO. As expected, interstitial collagen deposition increased in control mice following UUO but decreased in vim −/− kidneys. Immunofluorescence analyses also revealed altered localization of β-catenin in vim −/− mice undergoing UUO without significant changes in mRNA levels. However, RNA sequencing revealed a decrease in β-catenin-dependent genes in vim −/− kidneys. Finally, vim-silenced HK-2 cell lines undergoing EMT were shown to have decreased cellular migration during wound healing. We conclude that vim inhibition decreases fibrosis following UUO by possibly altering β-catenin localization and downstream signaling.


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