scholarly journals The MEK Inhibitor Trametinib Ameliorates Kidney Fibrosis by Suppressing ERK1/2 and mTORC1 Signaling

2018 ◽  
Vol 30 (1) ◽  
pp. 33-49 ◽  
Author(s):  
Petros Andrikopoulos ◽  
Julius Kieswich ◽  
Sabrina Pacheco ◽  
Luxme Nadarajah ◽  
Steven Michael Harwood ◽  
...  
Keyword(s):  
Renal Fibrosis ◽  
Molecular Mechanisms ◽  
Smooth Muscle Actin ◽  
Human Fibroblasts ◽  
Immunoblot Analysis ◽  
Potential Candidate ◽  
Renal Disorder ◽  
Kidney Fibrosis ◽  
Mtorc1 Signaling

BackgroundDuring kidney fibrosis, a hallmark and promoter of CKD (regardless of the underlying renal disorder leading to CKD), the extracellular-regulated kinase 1/2 (ERK1/2) pathway, is activated and has been implicated in the detrimental differentiation and expansion of kidney fibroblasts. An ERK1/2 pathway inhibitor, trametinib, is currently used in the treatment of melanoma, but its efficacy in the setting of CKD and renal fibrosis has not been explored.MethodsWe investigated whether trametinib has antifibrotic effects in two mouse models of renal fibrosis—mice subjected to unilateral ureteral obstruction (UUO) or fed an adenine-rich diet—as well as in cultured primary human fibroblasts. We also used immunoblot analysis, immunohistochemical staining, and other tools to study underlying molecular mechanisms for antifibrotic effects.ResultsTrametinib significantly attenuated collagen deposition and myofibroblast differentiation and expansion in UUO and adenine-fed mice. We also discovered that in injured kidneys, inhibition of the ERK1/2 pathway by trametinib ameliorated mammalian target of rapamycin complex 1 (mTORC1) activation, another key profibrotic signaling pathway. Trametinib also inhibited the ERK1/2 pathway in cultured primary human renal fibroblasts stimulated by application of TGF-β1, the major profibrotic cytokine, thereby suppressing downstream mTORC1 pathway activation. Additionally, trametinib reduced the expression of myofibroblast marker α-smooth muscle actin and the proliferation of renal fibroblasts, corroborating our in vivo data. Crucially, trametinib also significantly ameliorated renal fibrosis progression when administered to animals subsequent to myofibroblast activation.ConclusionsFurther study of trametinib as a potential candidate for the treatment of chronic renal fibrotic diseases of diverse etiologies is warranted.

scholarly journals In vivo silencing of amphiregulin by a novel effective Self-Assembled-Micelle inhibitory RNA ameliorates renal fibrosis via inhibition of EGFR signals

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Seung Seob Son ◽  
Soohyun Hwang ◽  
Jun Hong Park ◽  
Youngho Ko ◽  
Sung-Il Yun ◽  
...  
Keyword(s):  
Mrna Expression ◽  
Adhesion Molecule ◽  
Renal Fibrosis ◽  
Smooth Muscle Actin ◽  
Intercellular Adhesion Molecule ◽  
Intercellular Adhesion Molecule 1 ◽  
Kidney Fibrosis ◽  
Self Assembled ◽  
Tgf Β1

AbstractAmphiregulin (AREG) is a transmembrane glycoprotein recently implicated in kidney fibrosis. Previously, we reported that the AREG-targeting Self-Assembled-Micelle inhibitory RNA (SAMiRNA-AREG) alleviated fibrosis by stably silencing the AREG gene, and reduced the side effects of conventional siRNA treatment of pulmonary fibrosis. However, the therapeutic effect of SAMiRNA-AREG in renal fibrosis has not been studied until now. We used two animal models of renal fibrosis generated by a unilateral ureteral obstruction (UUO) and an adenine diet (AD) to investigate whether SAMiRNA-AREG inhibited renal fibrosis. To investigate the delivery of SAMiRNA-AREG to the kidney, Cy5-labeled SAMiRNA-AREG was injected into UUO- and AD-induced renal fibrosis models. In both kidney disease models, SAMiRNA-AREG was delivered primarily to the damaged kidney. We also confirmed the protective effect of SAMiRNA-AREG in renal fibrosis models. SAMiRNA-AREG markedly decreased the UUO- and AD-induced AREG mRNA expression. Furthermore, the mRNA expression of fibrosis markers, including α-smooth muscle actin, fibronectin, α1(I) collagen, and α1(III) collagen in the UUO and AD-induced kidneys, was diminished in the SAMiRNA-AREG-treated mice. The transcription of inflammatory markers (tumor necrosis factor-α and monocyte chemoattractant protein-1) and adhesion markers (vascular cell adhesion molecule 1 and intercellular adhesion molecule 1) was attenuated. The hematoxylin and eosin, Masson’s trichrome, and immunohistochemical staining results showed that SAMiRNA-AREG decreased renal fibrosis, AREG expression, and epidermal growth factor receptor (EGFR) phosphorylation in the UUO- and AD-induced models. Moreover, we studied the effects of SAMiRNA-AREG in response to TGF-β1 in mouse and human proximal tubule cells, and mouse fibroblasts. TGF-β1-induced extracellular matrix production and myofibroblast differentiation were attenuated by SAMiRNA-AREG. Finally, we confirmed that upregulated AREG in the UUO or AD models was mainly localized in the distal tubules. In conclusion, SAMiRNA-AREG represents a novel siRNA therapeutic for renal fibrosis by suppressing EGFR signals.

scholarly journals SLC36A1-mTORC1 signaling drives acquired resistance to CDK4/6 inhibitors

2019 ◽  
Vol 5 (9) ◽  
pp. eaax6352 ◽  
Author(s):  
Akihiro Yoshida ◽  
Yiwen Bu ◽  
Shuo Qie ◽  
John Wrangle ◽  
E. Ramsay Camp ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Fragile X ◽  
Acquired Resistance ◽  
Mammalian Target Of Rapamycin ◽  
Cyclin Dependent Kinase ◽  
Solute Carrier Family ◽  
Potential Therapeutic Target ◽  
Mtorc1 Signaling ◽  
Solute Carrier

The cyclin-dependent kinase 4/6 (CDK4/6) kinase is dysregulated in melanoma, highlighting it as a potential therapeutic target. CDK4/6 inhibitors are being evaluated in trials for melanoma and additional cancers. While beneficial, resistance to therapy is a concern, and the molecular mechanisms of such resistance remain undefined. We demonstrate that reactivation of mammalian target of rapamycin 1 (mTORC1) signaling through increased expression of the amino acid transporter, solute carrier family 36 member 1 (SLC36A1), drives resistance to CDK4/6 inhibitors. Increased expression of SLC36A1 reflects two distinct mechanisms: (i) Rb loss, which drives SLC36A1 via reduced suppression of E2f; (ii) fragile X mental retardation syndrome–associated protein 1 overexpression, which promotes SLC36A1 translation and subsequently mTORC1. Last, we demonstrate that a combination of a CDK4/6 inhibitor with an mTORC1 inhibitor has increased therapeutic efficacy in vivo, providing an important avenue for improved therapeutic intervention in aggressive melanoma.

scholarly journals TIMP-1 Induces α-Smooth Muscle Actin in Fibroblasts to Promote Urethral Scar Formation

2015 ◽  
Vol 35 (6) ◽  
pp. 2233-2243 ◽  
Author(s):  
Yinglong Sa ◽  
Chao Li ◽  
Hongbin Li ◽  
Hailin Guo
Keyword(s):  
Smooth Muscle ◽  
Molecular Mechanisms ◽  
Transforming Growth Factor ◽  
Smooth Muscle Actin ◽  
Human Fibroblasts ◽  
Mapk Signaling ◽  
Scar Formation ◽  
Dependent Manner ◽  
Muscle Actin ◽  
Mesenchymal Transition

Background/Aims: Tissue inhibitor of metalloproteinases-1 (TIMP-1) has been reported to upregulate in urethral scar. However, the underlying molecular mechanisms remain undefined. Methods: Here, we studied levels of TIMP-1 and α-smooth muscle actin (α-SMA) in the fibroblasts isolated from urethral scar tissues, compared to the fibroblasts isolated from normal urethra. Then we either overexpressed TIMP-1, or inhibited TIMP-1 by lentiviruses carrying a transgene or a short hairpin small interfering RNA for TIMP-1 in human fibroblasts. We examined the effects of modulation of TIMP-1 on α-SMA, and on epithelial-mesenchymal transition (EMT)-related genes. We also studied the underlying mechanisms. Results: We detected significantly higher levels of TIMP-1 and α-smooth muscle actin (α-SMA) in the fibroblasts isolated from urethral scar tissues, compared to the fibroblasts isolated from normal urethra. Moreover, the levels of TIMP-1 and α-SMA strongly correlated. Moreover, we found that TIMP-1 significantly increased levels of α-SMA, transforming growth factor β 1 (TGFβ1), Collagen I and some other key factors related to an enhanced EMT, suggesting that TIMP-1 may induce transformation of fibroblasts into myofibroblasts to promote tissue EMT to enhance the formation of urethral scar. Moreover, increases in TIMP-1 also induced an increase in fibroblast cell growth and cell invasion, in an ERK/MAPK-signaling-dependent manner. Conclusion: Our study thus highlights a pivotal role of TIMP-1 in urethral scar formation.

Twist1 Regulates Macrophage Plasticity To Promote Renal Fibrosis Through Galectin-3

2021 ◽  
Author(s):  
Qingfeng Wu ◽  
Shiren Sun ◽  
Lei Wei ◽  
Minna Liu ◽  
Hao Liu ◽  
...  
Keyword(s):  
Renal Fibrosis ◽  
Molecular Mechanisms ◽  
Interstitial Fibrosis ◽  
Macrophage Polarization ◽  
M2 Macrophage ◽  
Kidney Fibrosis ◽  
Galectin 3 ◽  
M2 Macrophage Polarization ◽  
Macrophage Plasticity ◽  
Stage Renal Disease

Abstract Renal interstitial fibrosis is the pathological basis of end-stage renal disease, in which the heterogeneity of macrophages in renal microenvironment plays an important role. However, the molecular mechanisms of macrophage plasticity during renal fibrosis progression remain unclear. In this study, we found for the first time that increased expression of Twist1 in macrophages was significantly associated with the severity of renal fibrosis in IgA nephropathy patients and mice with unilateral ureteral obstruction (UUO). Ablation of Twist1 in macrophages markedly alleviated renal tubular injury and renal fibrosis in UUO mice, accompanied by a lower extent of macrophage infiltration and M2 polarization in the kidney. The knockdown of Twist1 inhibited the chemotaxis and migration of macrophages, at least partially, through the CCL2/CCR2 axis. Twist1 downregulation inhibited M2 macrophage polarization and reduced the secretion of the profibrotic factors Arg1, MR (CD206), IL-10, and TGF-β. Galectin-3 was decreased in the macrophages of the conditional Twist1-deficient mice, and Twist1 was shown to directly activate galectin-3 transcription. Up-regulation of galectin-3 recovered Twist1-mediated M2 macrophage polarization. In conclusion, Twist1/galectin-3 signaling regulates macrophage plasticity (M2 phenotype) and promotes renal fibrosis. This study could suggest new strategies for delaying kidney fibrosis in patients with chronic kidney disease.

scholarly journals Inhibition of PTEN Activity Aggravates Post Renal Fibrosis in Mice with Ischemia Reperfusion-Induced Acute Kidney Injury

2017 ◽  
Vol 43 (5) ◽  
pp. 1841-1854 ◽  
Author(s):  
Jun Zhou ◽  
Jiying  Zhong ◽  
Sen  Lin ◽  
Zhenxing Huang ◽  
Hongtao Chen ◽  
...  
Keyword(s):  
Chronic Kidney Disease ◽  
Acute Kidney Injury ◽  
Kidney Disease ◽  
Renal Fibrosis ◽  
Smooth Muscle Actin ◽  
Ischemia Reperfusion ◽  
Specific Inhibitor ◽  
Kidney Injury ◽  
Control Group ◽  
Kidney Fibrosis

Background: Renal fibrosis is a common pathophysiological feature of chronic kidney disease. Acute kidney injury (AKI) is defined as an independent causal factor of chronic kidney disease, with a pathological representation of post renal fibrosis. However, the etiopathogenesis underlying post renal fibrosis induced by AKI is not completely understood. Methods: BALB/c mice were treated with bpv or vehicle controls and were, respectively, the ischemia reperfusion (IR) model group and control group. All of the animals had blood taken from the orbital venous plexus at 24 hours after IR. Six mice in each group were randomly chosen and euthanized 7 days after IR treatment, and the remaining six mice in each group were euthanized 14 days after IR treatment. We examined the effect on post kidney fibrosis of inhibiting PTEN activity in mice in an IR induced AKI experimental model. Results: Compared with vehicle mice, bpv-(PTEN specific inhibitor) treated mice accumulated more bone marrow-derived fibroblasts and myofibroblasts in the kidneys. Inhibition of PTEN activity increased the expression of α-smooth muscle actin and extracellular matrix proteins and post kidney fibrosis. Furthermore, inhibition of PTEN activity resulted in more inflammatory cytokines in the kidneys of mice subjected to IR-induced renal fibrosis. Moreover, inhibition of PTEN activity up-regulated PI3K protein expression and Akt phosphorylation. Conclusions: Our study demonstrated that PTEN played an important role in post renal fibrosis in mice with ischemia reperfusion-induced AKI. These results indicated that the PTEN/PI3K/Akt signaling pathway may serve as a novel therapeutic target for AKI-induced chronic kidney disease.

The role of endoglin in kidney fibrosis

2014 ◽  
Vol 16 ◽  
Author(s):  
Jose M. Muñoz-Felix ◽  
Barbara Oujo ◽  
Jose M. Lopez-Novoa
Keyword(s):  
Transforming Growth Factor Beta ◽  
Renal Fibrosis ◽  
Transforming Growth Factor ◽  
Mesangial Cells ◽  
Cell Types ◽  
Experimental Models ◽  
Kidney Fibrosis ◽  
End Stage

Tubulointerstitial fibrosis and glomerulosclerosis, are a major feature of end stage chronic kidney disease (CKD), characterised by an excessive accumulation of extracellular matrix (ECM) proteins. Transforming growth factor beta-1 (TGF-β1) is a cytokine with an important role in many steps of renal fibrosis such as myofibroblast activation and proliferation, ECM protein synthesis and inflammatory cell infiltration. Endoglin is a TGF-β co-receptor that modulates TGF-β responses in different cell types. In numerous cells types, such as mesangial cells or myoblasts, endoglin regulates negatively TGF-β-induced ECM protein expression. However, recently it has been demonstrated that ‘in vivo’ endoglin promotes fibrotic responses. Furthermore, several studies have demonstrated an increase of endoglin expression in experimental models of renal fibrosis in the kidney and other tissues. Nevertheless, the role of endoglin in renal fibrosis development is unclear and a question arises: Does endoglin protect against renal fibrosis or promotes its development? The purpose of this review is to critically analyse the recent knowledge relating to endoglin and renal fibrosis. Knowledge of endoglin role in this pathology is necessary to consider endoglin as a possible therapeutic target against renal fibrosis.

scholarly journals Effect of Shenkang on renal fibrosis and activation of renal interstitial fibroblasts through the JAK2/STAT3 pathway

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Tianyu Qin ◽  
You Wu ◽  
Tonghua Liu ◽  
Lili Wu
Keyword(s):  
Renal Fibrosis ◽  
Sham Group ◽  
Smooth Muscle Actin ◽  
Protective Action ◽  
Underlying Mechanism ◽  
Cytokine Signaling ◽  
Stat3 Pathway ◽  
Fibroblast Activation

Abstract Background Activation of renal fibroblasts is a critical mechanism in the process of renal fibrosis. As a commonly used herbal formula, Shenkang (SK) has been found to attenuate renal fibrosis and renal parenchyma destruction. However, the effect of SK on renal fibroblast activation in unilateral ureteral obstruction (UUO) mice and its molecular mechanism remain undetermined. The present study was performed to elucidate the effect of SK on renal fibroblast activation and renal fibrosis, as well as the potential underlying mechanism, in both NRK-49F cells and UUO mice. Methods NRK-49F cells were stimulated with 10 ng/ml TGF-β1 for 48 h. After SK treatment, the CCK-8 method was used to evaluate cell viability. Thirty-six C57BL/6 mice were randomly divided into the sham group, UUO group, angiotensin receptor blocker (ARB) group, and SK high-, moderate- and low-dose groups. UUO was induced in mice except those in the sham group. Drugs were administered 1 day later. On the 13th day, the fractional anisotropy (FA) value was determined by MRI to evaluate the degree of renal fibrosis. After 14 days, serum indexes were assessed. Hematoxylin and eosin (HE) and Sirius red staining were used to observe pathological morphology and the degree of fibrosis of the affected kidney. Western blotting and PCR were used to assess the expression of related molecules in both cells and animals at the protein and gene levels. Results Our results showed that SK reduced extracellular matrix (ECM) and α-smooth muscle actin (α-SMA) expression both in vitro and in vivo and attenuated renal fibrosis and the pathological lesion degree after UUO, suppressing JAK2/STAT3 activation. Furthermore, we found that SK regulated the JAK2/STAT3 pathway regulators peroxiredoxin 5 (Prdx5) in vitro and suppressor of cytokine signaling protein 1 (SOCS1) and SOCS3 in vivo. Conclusions These results indicated that SK inhibited fibroblast activation by regulating the JAK2/STAT3 pathway, which may be a mechanism underlying its protective action in renal fibrosis.

scholarly journals miR-155-5p Implicates in the Pathogenesis of Renal Fibrosis via Targeting SOCS1 and SOCS6

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Wanfen Zhang ◽  
Xiaoping Li ◽  
Yushang Tang ◽  
Cheng Chen ◽  
Ran Jing ◽  
...  
Keyword(s):  
Renal Fibrosis ◽  
Molecular Mechanisms ◽  
Kidney Diseases ◽  
Unilateral Ureteral Obstruction ◽  
Independent Manner ◽  
Rat Models ◽  
End Stage ◽  
Clinical Prevention

Renal fibrosis is associated with the reduction in the functional renal parenchyma and in most cases progresses to end-stage kidney failure, a devastating condition that requires lifelong dialysis or kidney transplantation. However, due to the extreme complexity in the pathogenesis of renal fibrosis and our limited knowledge, therapeutic options for renal fibrosis in the clinical setting are still scarce and often ineffective. Hence, further studies on the molecular mechanisms underlying renal fibrosis are compellingly needed. Multiple miRNAs have demonstrated to participate in kidney diseases in a TGF-β dependent or independent manner, but there is very little known about miR-155-5p on renal fibrosis. In the present study, we firstly explored the expression level and functions of miR-155-5p in the setting of renal fibrosis. Our research revealed that miR-155-5p is highly expressed in kidney tissues from patients and unilateral ureteral obstruction (UUO) rat models, and miR-155-5p knockdown significantly blocks renal fibrosis both in vivo and in vitro. In mechanism, our data demonstrate that miR-155-5p promotes renal fibrosis by increasing the phosphorylated activation of STAT3 via targeting SOCS1/6. Altogether, our findings highlight a miR-155-5p/SOCS/STAT3 axis in the pathogenesis of renal fibrosis, which may provide promising therapeutic targets for clinical prevention of this disease.

scholarly journals p21waf1/cip1/sdi1 as a Central Regulator of Inducible Smooth Muscle Actin Expression and Differentiation of Cardiac Fibroblasts to Myofibroblasts

2007 ◽  
Vol 18 (12) ◽  
pp. 4837-4846 ◽  
Author(s):  
Sashwati Roy ◽  
Savita Khanna ◽  
Trenton Rink ◽  
Jared Radtke ◽  
W. Taylor Williams ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Molecular Mechanisms ◽  
Cardiac Fibroblasts ◽  
Smooth Muscle Actin ◽  
Ischemia Reperfusion ◽  
Boundary Region ◽  
Muscle Actin ◽  
Phenotypic Switch ◽  
Infarct Region

The phenotypic switch of cardiac fibroblasts (CFs) to myofibroblasts is essential for normal and pathological wound healing. Relative hyperoxic challenge during reoxygenation causes myocardial remodeling. Here, we sought to characterize the novel O2-sensitive molecular mechanisms responsible for triggering the differentiation of CFs to myofibroblasts. Exposure of CFs to hyperoxic challenge–induced transcription of smooth muscle actin (SMA) and enhanced the stability of both Acta2 transcript as well as of SMA protein. Both p21 deficiency as well as knockdown blunted hyperoxia-induced Acta2 and SMA response. Strikingly, overexpression of p21 alone markedly induced differentiation of CFs under normoxia. Overexpression of p21 alone induced SMA transcription by down-regulating YB1 and independent of TGFβ1. In vivo, hyperoxic challenge induced p21-dependent differentiation of CFs to myofibroblasts in the infarct boundary region of ischemia-reperfused heart. Tissue elements were laser-captured from infarct boundary and from a noninfarct region 0.5 mm away. Reperfusion caused marked p21 induction in the infarct region. Acta2 as well as SMA expression were markedly up-regulated in CF-rich infarct boundary region. Of note, ischemia-reperfusion–induced up-regulation of Acta2 in the infarct region was completely abrogated in p21-deficient mice. This observation establishes p21 as a central regulator of reperfusion-induced phenotypic switch of CFs to myofibroblasts.

scholarly journals Fgfr2 is integral for bladder mesenchyme patterning and function

2015 ◽  
Vol 308 (8) ◽  
pp. F888-F898 ◽  
Author(s):  
K. A. Walker ◽  
Y. Ikeda ◽  
I. Zabbarova ◽  
C. M. Schaefer ◽  
D. Bushnell ◽  
...  
Keyword(s):  
Cell Fate ◽  
Ex Vivo ◽  
Smooth Muscle Actin ◽  
Three Dimensional ◽  
Growth Factor Receptor ◽  
Immunoblot Analysis ◽  
Type Ia ◽  
And Function ◽  
Passive Stretch

While urothelial signals, including sonic hedgehog (Shh), drive bladder mesenchyme differentiation, it is unclear which pathways within the mesenchyme are critical for its development. Studies have shown that fibroblast growth factor receptor (Fgfr)2 is necessary for kidney and ureter mesenchymal development. The objective of the present study was to determine the role of Fgfr2 in the bladder mesenchyme. We used Tbx18cre mice to delete Fgfr2 in the bladder mesenchyme ( Fgfr2 BM−/−). We performed three-dimensional reconstructions, quantitative real-time PCR, in situ hybridization, immunolabeling, ELISAs, immunoblot analysis, void stain on paper, ex vivo bladder sheet assays, and in vivo decerebrated cystometry. Compared with control bladders, embryonic day 16.5 (E16.5) Fgfr2 BM−/− bladders had thin muscle layers with less α-smooth muscle actin and thickened lamina propria with increased collagen type Ia and IIIa that intruded into the muscle. The reciprocal changes in mutant layer thicknesses appeared partly due to a cell fate switch. From postnatal days 1 to 30, Fgfr2 BM−/− bladders demonstrated progressive muscle loss and increased collagen expression. Postnatal Fgfr2 BM−/− bladder sheets exhibited decreased agonist-mediated contractility and increased passive stretch tension versus control bladder sheets. Cystometry revealed high baseline and threshold pressures and shortened intercontractile intervals in Fgfr2 BM−/− versus control bladders. Mechanistically, whereas Shh expression appeared normal, mRNA and protein readouts of hedgehog activity were increased in E16.5 Fgfr2 BM−/− versus control bladders. Moreover, E16.5 Fgfr2 BM−/− bladders exhibited higher levels of Cdo and Boc, hedgehog coreceptors that enhance sensitivity to Shh, compared with control bladders. In conclusion, loss of Fgfr2 in the bladder mesenchyme leads to abnormal bladder morphology and decreased compliance and contractility.

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