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Li J, Hu G, Liu W, Cao X, Chen G, Peng F, Xiaofang X, Peng C. Patchouli alcohol against renal fibrosis of spontaneously hypertensive rats via Ras/Raf-1/ERK1/2 signalling pathway. J Pharm Pharmacol 2023:7161501. [PMID: 37177974 DOI: 10.1093/jpp/rgad032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Accepted: 04/04/2023] [Indexed: 05/15/2023]
Abstract
OBJECTIVES The present study was designed to obverse the protection of patchouli alcohol (PA) ameliorates hypertensive nephropathy in spontaneously hypertensive rats (SHR) and reveals potential mechanism. METHODS Briefly, the adult spontaneously hypertensive rats (SHR) or Wistar-Kyoto (WKY) rats (half male and half female) were intragastric gavaged or not with PA (80, 40 and 20 mg/kg) for 8 weeks. Body weight, blood pressure (BP), renal weight, renal function and renal morphology were measured. Further, western blotting and immunohistochemical analysis were used to study the underlying mechanism. KEY FINDINGS Compared with the WKY group, plasmatic levels of renin, angiotensin II (Ang-II), transforming growth factor beta 1(TGF-β1), plasminogen activator inhibitor-1(PAI-1), creatinine (Cr), blood urea nitrogen (BUN), renal index, mRNA levels of ERK1/2 and α-SMA were significantly increased in SHR. Histology results showed that renal tubular injury and tubulointerstitial fibrosis occurred in SHR. After administration, SBP of captopril group decreased at each week after administration, especially at 3, 5, 6 7 and 8 weeks (P < 0.05 or P < 0.01). There is no significant effect was assessed in the olive oil group. Decreased plasma Cr, Renin, Ang-II, TGF-β1, PAI-1, SCFAs and Renin, TGF-β1, PAI-1 in renal tissues were observed significantly in captopril (P <0.05 or P < 0.01). Plasma BUN, Ang-II, TGF-β1 and PAI-1 in renal tissues decreased in the olive oil group significantly (P <0.05 or P < 0.01). PA (80, 40 and 20 mg/kg) lowered BP and plasmatic levels of Renin, Ang-II, TGF-β1 and PAI-1. Treatment with PA (40, 20 mg/kg) decreased levels of Cr, BUN and suppressed of activation of pro-fibrosis cytokines including TGF-β1 in kidney. There is no ameliorative change in the olive oil group and the captopril group (P > 0.05) while PA treatment alleviated renal tubular injury and produced dramatic collagen fibre area reductions in mesangial membrane, basement membrane, and renal interstitium obviously (P < 0.05 or P < 0.01). Treatment of SHR with PA-inhibited MFB activation and downregulated mRNA of α-SMA. Treatment with PA suppressed excessive production of the extracellular matrix (ECM) via decreasing Col I, III and FN, downregulating mRNA of tissue inhibitor of TIMP-1 along with upregulating mRNA of MMP-9. The expression of Col III and MMP-9 mRNA-reduced in the captopril group (P < 0.05). In addition, the expression of ERK1/2 and pERK1/2 also reduced in the captopril group significantly (P < 0.05 or P < 0.01). Treatment with PA (20 mg/kg) downregulated proteins expression of Raf-1, ERK1/2 and pERK1/2 and mRNA expression of Ras, Raf-1 and ERK1/2. CONCLUSIONS Overall, PA restored normal BP, alleviated renal dysfunction and renal fibrosis, possibly by suppressing Ang II and TGF-β1-mediated Ras/Raf-1/ERK1/2 signalling pathway.
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Affiliation(s)
- Jing Li
- Key Laboratory of Southwestern Chinese Medicine Resources, Key Laboratory of standardization of Chinese herbal medicine of MOE, Chengdu University of Traditional Chinese Medicine, Chengdu, PR China
| | - Guanying Hu
- Key Laboratory of Southwestern Chinese Medicine Resources, Key Laboratory of standardization of Chinese herbal medicine of MOE, Chengdu University of Traditional Chinese Medicine, Chengdu, PR China
| | - Wenxiu Liu
- Key Laboratory of Southwestern Chinese Medicine Resources, Key Laboratory of standardization of Chinese herbal medicine of MOE, Chengdu University of Traditional Chinese Medicine, Chengdu, PR China
| | - Xiaoyu Cao
- Key Laboratory of Southwestern Chinese Medicine Resources, Key Laboratory of standardization of Chinese herbal medicine of MOE, Chengdu University of Traditional Chinese Medicine, Chengdu, PR China
| | - Guanru Chen
- Key Laboratory of Southwestern Chinese Medicine Resources, Key Laboratory of standardization of Chinese herbal medicine of MOE, Chengdu University of Traditional Chinese Medicine, Chengdu, PR China
| | - Fu Peng
- Department of Pharmacology, Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry, Sichuan Engineering Laboratory for Plant-Sourced Drug and Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University, Chengdu, PR China
| | - Xie Xiaofang
- Key Laboratory of Southwestern Chinese Medicine Resources, Key Laboratory of standardization of Chinese herbal medicine of MOE, Chengdu University of Traditional Chinese Medicine, Chengdu, PR China
| | - Cheng Peng
- Key Laboratory of Southwestern Chinese Medicine Resources, Key Laboratory of standardization of Chinese herbal medicine of MOE, Chengdu University of Traditional Chinese Medicine, Chengdu, PR China
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Dissecting the Involvement of Ras GTPases in Kidney Fibrosis. Genes (Basel) 2021; 12:genes12060800. [PMID: 34073961 PMCID: PMC8225075 DOI: 10.3390/genes12060800] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 05/19/2021] [Accepted: 05/20/2021] [Indexed: 12/30/2022] Open
Abstract
Many different regulatory mechanisms of renal fibrosis are known to date, and those related to transforming growth factor-β1 (TGF-β1)-induced signaling have been studied in greater depth. However, in recent years, other signaling pathways have been identified, which contribute to the regulation of these pathological processes. Several studies by our team and others have revealed the involvement of small Ras GTPases in the regulation of the cellular processes that occur in renal fibrosis, such as the activation and proliferation of myofibroblasts or the accumulation of extracellular matrix (ECM) proteins. Intracellular signaling mediated by TGF-β1 and Ras GTPases are closely related, and this interaction also occurs during the development of renal fibrosis. In this review, we update the available in vitro and in vivo knowledge on the role of Ras and its main effectors, such as Erk and Akt, in the cellular mechanisms that occur during the regulation of kidney fibrosis (ECM synthesis, accumulation and activation of myofibroblasts, apoptosis and survival of tubular epithelial cells), as well as the therapeutic strategies for targeting the Ras pathway to intervene on the development of renal fibrosis.
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Long-term treatment with chaethomellic acid A reduces glomerulosclerosis and arteriolosclerosis in a rat model of chronic kidney disease. Biomed Pharmacother 2017; 96:489-496. [PMID: 29032332 DOI: 10.1016/j.biopha.2017.09.137] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Revised: 09/26/2017] [Accepted: 09/26/2017] [Indexed: 11/21/2022] Open
Abstract
The high prevalence of end-stage renal disease emphasizes the failure to provide therapies to effectively prevent and/or reverse renal fibrosis. Therefore, the aim of this study was to evaluate the effect of long-term treatment with chaethomellic acid A (CAA), which selectively blocks Ha-Ras farnesylation, on renal mass reduction-induced renal fibrosis. Male Wistar rats were sham-operated (SO) or subjected to 5/6 renal mass reduction (RMR). One week after surgery, rats were placed in four experimental groups: SO:SO rats without treatment (n=13); SO+CAA: SO rats treated with CAA (n=13); RMR:RMR rats without treatment (n=14); and RMR+CAA:RMR rats treated with CAA (n=13). CAA was intraperitoneally administered in a dose of 0.23μg/kg three times a week for six months. Renal fibrosis was evaluated by two-dimensional ultrasonography and histopathological analysis. The kidneys of the RMR animals treated with CAA showed a significantly decrease in the medullary echogenicity (p<0.05) compared with the RMR rats that received no treatment. Glomerulosclerosis and arteriolosclerosis scores were significantly lower (p<0.001) in the RMR+CAA group when compared with the RMR group. There were no significant differences in interstitial fibrosis, interstitial inflammation and tubular dilatation scores between the RMR+CAA and RMR groups. These data suggest that CAA can be a potential future drug to attenuate the progression of chronic kidney disease.
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4
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Muñoz-Félix JM, Fuentes-Calvo I, Cuesta C, Eleno N, Crespo P, López-Novoa JM, Martínez-Salgado C. Absence of K-Ras Reduces Proliferation and Migration But Increases Extracellular Matrix Synthesis in Fibroblasts. J Cell Physiol 2016; 231:2224-35. [PMID: 26873620 DOI: 10.1002/jcp.25340] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 02/10/2016] [Indexed: 02/06/2023]
Abstract
The involvement of Ras-GTPases in the development of renal fibrosis has been addressed in the last decade. We have previously shown that H- and N-Ras isoforms participate in the regulation of fibrosis. Herein, we assessed the role of K-Ras in cellular processes involved in the development of fibrosis: proliferation, migration, and extracellular matrix (ECM) proteins synthesis. K-Ras knockout (KO) mouse embryonic fibroblasts (K-ras(-/-) ) stimulated with transforming growth factor-β1 (TGF-β1) exhibited reduced proliferation and impaired mobility than wild-type fibroblasts. Moreover, an increase on ECM production was observed in K-Ras KO fibroblasts in basal conditions. The absence of K-Ras was accompanied by reduced Ras activation and ERK phosphorylation, and increased AKT phosphorylation, but no differences were observed in TGF-β1-induced Smad signaling. The MEK inhibitor U0126 decreased cell proliferation independently of the presence of K-ras but reduced migration and ECM proteins expression only in wild-type fibroblasts, while the PI3K-AKT inhibitor LY294002 decreased cell proliferation, migration, and ECM synthesis in both types of fibroblasts. Thus, our data unveil that K-Ras and its downstream effector pathways distinctively regulate key biological processes in the development of fibrosis. Moreover, we show that K-Ras may be a crucial mediator in TGF-β1-mediated effects in this cell type. J. Cell. Physiol. 231: 2224-2235, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- José M Muñoz-Félix
- Unidad de Fisiopatología Renal y Cardiovascular, Departamento de Fisiología y Farmacología, Instituto "Reina Sofía" de Investigación Nefrológica, Universidad de Salamanca, Salamanca, Spain.,Instituto de Investigación Biomédica de Salamanca (IBSAL), Salamanca, Spain
| | - Isabel Fuentes-Calvo
- Unidad de Fisiopatología Renal y Cardiovascular, Departamento de Fisiología y Farmacología, Instituto "Reina Sofía" de Investigación Nefrológica, Universidad de Salamanca, Salamanca, Spain.,Instituto de Investigación Biomédica de Salamanca (IBSAL), Salamanca, Spain
| | - Cristina Cuesta
- Unidad de Fisiopatología Renal y Cardiovascular, Departamento de Fisiología y Farmacología, Instituto "Reina Sofía" de Investigación Nefrológica, Universidad de Salamanca, Salamanca, Spain.,Instituto de Investigación Biomédica de Salamanca (IBSAL), Salamanca, Spain
| | - Nélida Eleno
- Unidad de Fisiopatología Renal y Cardiovascular, Departamento de Fisiología y Farmacología, Instituto "Reina Sofía" de Investigación Nefrológica, Universidad de Salamanca, Salamanca, Spain.,Instituto de Investigación Biomédica de Salamanca (IBSAL), Salamanca, Spain
| | - Piero Crespo
- Facultad de Medicina, Departamento de Biología Molecular, Instituto de Biomedicina y Biotecnología de Cantabria, Consejo Superior de Investigaciones Científicas-IDICAN-Universidad de Cantabria, Santander, Spain
| | - José M López-Novoa
- Unidad de Fisiopatología Renal y Cardiovascular, Departamento de Fisiología y Farmacología, Instituto "Reina Sofía" de Investigación Nefrológica, Universidad de Salamanca, Salamanca, Spain.,Instituto de Investigación Biomédica de Salamanca (IBSAL), Salamanca, Spain
| | - Carlos Martínez-Salgado
- Unidad de Fisiopatología Renal y Cardiovascular, Departamento de Fisiología y Farmacología, Instituto "Reina Sofía" de Investigación Nefrológica, Universidad de Salamanca, Salamanca, Spain.,Instituto de Investigación Biomédica de Salamanca (IBSAL), Salamanca, Spain.,Instituto de Estudios de Ciencias de la Salud de Castilla y León (IECSCYL), Unidad de Investigación, Hospital Universitario de Salamanca, Salamanca, Spain
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Effect of angiotensin II and small GTPase Ras signaling pathway inhibition on early renal changes in a murine model of obstructive nephropathy. BIOMED RESEARCH INTERNATIONAL 2014; 2014:124902. [PMID: 25101263 PMCID: PMC4101960 DOI: 10.1155/2014/124902] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Revised: 05/12/2014] [Accepted: 06/06/2014] [Indexed: 12/12/2022]
Abstract
Tubulointerstitial fibrosis is a major feature of chronic kidney disease. Unilateral ureteral obstruction (UUO) in rodents leads to the development of renal tubulointerstitial fibrosis consistent with histopathological changes observed in advanced chronic kidney disease in humans. The purpose of this study was to assess the effect of inhibiting angiotensin II receptors or Ras activation on early renal fibrotic changes induced by UUO. Animals either received angiotensin II or underwent UUO. UUO animals received either losartan, atorvastatin, and farnesyl transferase inhibitor (FTI) L-744,832, or chaetomellic acid A (ChA). Levels of activated Ras, phospho-ERK1/2, phospho-Akt, fibronectin, and α-smooth muscle actin were subsequently quantified in renal tissue by ELISA, Western blot, and/or immunohistochemistry. Our results demonstrate that administration of angiotensin II induces activation of the small GTPase Ras/Erk/Akt signaling system, suggesting an involvement of angiotensin II in the early obstruction-induced activation of renal Ras. Furthermore, upstream inhibition of Ras signalling by blocking either angiotensin AT1 type receptor or by inhibiting Ras prenylation (atorvastatin, FTI o ChA) reduced the activation of the Ras/Erk/Akt signaling system and decreased the early fibrotic response in the obstructed kidney. This study points out that pharmacological inhibition of Ras activation may hold promise as a future strategy in the prevention of renal fibrosis.
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6
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Wang JH, Newbury LJ, Knisely AS, Monia B, Hendry BM, Sharpe CC. Antisense knockdown of Kras inhibits fibrosis in a rat model of unilateral ureteric obstruction. THE AMERICAN JOURNAL OF PATHOLOGY 2011; 180:82-90. [PMID: 22074740 DOI: 10.1016/j.ajpath.2011.09.036] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2011] [Revised: 08/26/2011] [Accepted: 09/26/2011] [Indexed: 11/28/2022]
Abstract
Tubulointerstitial fibrosis is the hallmark of chronic kidney disease and is characterized by an increase in the number and activity of interstitial fibroblasts and by excessive matrix deposition. Ras is an intracellular signaling molecule involved in cell proliferation and differentiation. It has recently been implicated in the pathogenesis of renal fibrosis. Of the three different isoforms of Ras (Kirsten, Harvey, and Neural), we previously demonstrated that the Kirsten isoform is key in the control of renal fibroblast proliferation in vitro. In this study, we used gene therapy in the form of antisense oligonucleotides (ASOs) specifically to silence Kras (alias Ki-ras) expression in a rat model of renal fibrosis caused by unilateral ureteric obstruction. We demonstrate that renal Kras expression increases by 70% in this model compared with sham-operated animals and that treatment with ASOs can reduce total renal Kras by >90% to levels well below basal. This silencing is associated with a dramatic inhibition of interstitial fibrosis, a fivefold reduction in α-smooth muscle actin expression, and a 2.4-fold reduction in collagen I deposition. This inhibition was observed despite histologic evidence of marked interstitial inflammation. These findings demonstrate that silencing Kras expression can markedly inhibit renal fibrosis. This strategy should be considered as a new potential therapeutic avenue.
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Affiliation(s)
- Jia-Hui Wang
- Department of Renal Medicine, King's College Hospital, London, United Kingdom
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7
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Abstract
The pathologic paradigm for renal progression is advancing tubulointerstitial fibrosis. Whereas mechanisms underlying fibrogenesis have grown in scope and understanding in recent decades, effective human treatment to directly halt or even reverse fibrosis remains elusive. Here, we examine key features mediating the molecular and cellular basis of tubulointerstitial fibrosis and highlight new insights that may lead to novel therapies. How to prevent chronic kidney disease from progressing to renal failure awaits even deeper biochemical understanding.
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Affiliation(s)
- Michael Zeisberg
- Division of Matrix Biology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA.
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8
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KRAS mutational status as a predictor of epidermal growth factor receptor inhibitor efficacy in colorectal cancer. Am J Ther 2010; 16:554-61. [PMID: 19352138 DOI: 10.1097/mjt.0b013e318199fa17] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Inhibitors of the epidermal growth factor receptor (EGFR) have demonstrated promising potential in the treatment of advanced colorectal cancer. However, a proportion of patients do not respond to therapy with EGFR inhibitors, and therefore, there has been interest in identifying those patients most likely to benefit from therapy with these agents. KRAS, a member of the RAS family of signaling proteins, plays an important role in EGFR-mediated regulation of cellular proliferation and survival. Although there is still some debate regarding the prognostic importance of KRAS mutations in patients with metastatic colorectal cancer, several recent phase 2 and 3 studies have identified the presence of mutations at codons 12 and 13 of KRAS as predictors of poor response to the anti-EGFR monoclonal antibodies panitumumab and cetuximab. Patients with wild-type KRAS were found to have significantly better progression-free survival, overall survival, and/or objective response rate compared with patients harboring KRAS mutations. As a result, there has been growing interest in the development of KRAS mutational status as a biomarker for predicting patient response to EGFR-targeted therapy. Screening colorectal tumors for the absence of KRAS mutations may help identify patients most likely to benefit from anti-EGFR therapies.
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Khwaja A, Sharpe CC, Noor M, Hendry BM. The role of geranylgeranylated proteins in human mesangial cell proliferation. Kidney Int 2006; 70:1296-304. [PMID: 16929252 DOI: 10.1038/sj.ki.5001713] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The Rho family of guanine 5'-triphosphatases (GTPases) play a key role in regulating cell proliferation, tubulointerstitial fibrosis, and glomerular hemodynamics. The post-translational prenylation of RhoGTPases by the addition of a geranylgeranyl moiety is critical for cellular localization and signaling activity. This study investigates the effects of (i) inhibiting geranylgeranylation (GG) in human mesangial cell (HMC) proliferation and apoptosis, using GGTI 298, a specific inhibitor of GG and (ii) lovastatin, an HMG-coacetyl A-reductase inhibitor, which depletes the availability of prenylation substrates. HMC proliferation was assessed using an assay of viable cell number and measuring bromodeoxyuridine (BrdU) incorporation. Hoechst 33342 staining was used to determine apoptosis. Extracellular signal-regulated protein kinase (Erk)1/2 and Akt activation were analysed by Western blotting. Rho activation was determined using the Rhotekin pull-down assay. Immunocytochemistry was performed to study the effects on the actin cytoskeleton and RhoA localization. GGTI 298 (10-20 muM) and lovastatin (5-10 muM) potently inhibited platelet-derived growth factor and serum-stimulated HMC proliferation and induced apoptosis. These effects of lovastatin were attenuated by co-incubation with geranylgeranylpyrophosphate. C3 exoenzyme, a clostridial toxin that specifically targets Rho also inhibited BrdU incorporation and promoted apoptosis. GGTI 298 increased cytosolic expression of RhoA, prevented RhoA activation, and inhibited the activation of Erk1/2 and the survival protein Akt. GGTI 298, lovastatin, and C3 exoenzyme inhibit HMC proliferation and promote apoptosis. Inhibiting GG increases cytosolic RhoA expression, disrupts the actin cytoskeleton, and inhibits RhoA activation. These results suggest that targeting geranylgeranylated proteins with statins or GGTI 298 is a promising therapeutic strategy in human mesangioproliferative renal disease.
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Affiliation(s)
- A Khwaja
- Department of Renal Medicine, GKT School of Medicine, King's College London, Bessemer Road, London, UK
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Khwaja A, Dockrell MEC, Hendry BM, Sharpe CC. Prenylation is not necessary for endogenous Ras activation in non-malignant cells. J Cell Biochem 2006; 97:412-22. [PMID: 16187291 DOI: 10.1002/jcb.20641] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Ras monomeric GTPases are pivotal to many core cellular processes such as proliferation and differentiation. The post-translational prenylation of Ras with a farnesyl or a geranylgeranyl moiety is thought to be critical for its membrane binding and consequent signaling activity. Inhibitors of Ras prenylation have an anti-proliferative effect in some Ras-transformed cells. We present a study of the effects of prenylation inhibitors on endogenous, wild-type Ras in three renal cell types, namely primary adult human renal fibroblasts, primary adult human mesangial cells, and a primate renal fibroblast cell line (Vero cells). We have previously demonstrated that Ras is necessary for normal proliferation in these cells. Here we show that Ras is farnesylated and not geranylgeranylated in all three cell types. Furthermore, inhibiting Ras farnesylation has no effect on cell proliferation or Ras activation. Although inhibiting geranylgeranylation in these cells does inhibit proliferation, this is through an Ras-independent mechanism. Non-prenylated Ras is able to localize to the plasma membrane, bind Raf when cells are stimulated by epidermal growth factor or platelet-derived growth factor, and activate the Ras downstream effectors mitogen-activated protein kinase and phosphotidylinositol 3-kinase. We conclude that in wild-type cells, endogenous Ras does not need to be prenylated to be active.
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Affiliation(s)
- Arif Khwaja
- Department of Renal Medicine, King's College London, Bessemer Road, London SE5 9PJ, United Kingdom
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11
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Abstract
The cellular Ras is known to play an important role in cellular proliferation mediated by growth factor receptor. Evidence also points to its role in growth arrest. Substantiated proof for growth-suppressive activity of wild-type Ras comes from studies that showed 1) loss of wild-type ras allele in tumors, 2) suppression of growth in cells transformed by oncogenic ras upon overexpression of wild-type Ras, and 3) up-regulation of Ras expression during postnatal development and following growth arrest of untransformed cells in culture. To understand the mechanism by which the wild-type Ras brings about these diverse actions, we evaluated its well-known role in actively proliferating cells and its less understood role in growth arrest. This led to the proposal that wild-type Ras in either GDP or GTP-bound state can antagonize the function of oncogenic Ras.-Singh, A., Sowjanya, A. P., Ramakrishna, G. The wild-type Ras: road ahead.
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Affiliation(s)
- Arvind Singh
- Centre for DNA Fingerprinting and Diagnostics, Nacharam, Hyderabad, Andhra Pradesh, India
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12
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Khwaja A, Sharpe CC, Noor M, Kloog Y, Hendry BM. The inhibition of human mesangial cell proliferation by S-trans, trans-farnesylthiosalicylic acid. Kidney Int 2005; 68:474-86. [PMID: 16014024 DOI: 10.1111/j.1523-1755.2005.00425.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Many of the proliferative cytokines implicated in human mesangial cell (HMC) proliferation signal through the superfamily of Ras GTPases. The Ras antagonist, S-trans, trans- farnesylthiosalicylic acid (FTS), was used to investigate the effects of the inhibition of Ras signaling on HMC proliferation. METHODS Ras expression and membrane localization, MAPK, and Akt activation were analyzed by Western blotting. Ras activation was determined with a pull-down assay using the Ras-binding domain of Raf. HMC growth curves were assessed using the MTS assay of viable cell number, while DNA synthesis was measured with BrdU incorporation. Hoechst 33342 staining was used to determine apoptosis. RESULTS FTS reduced the membrane localization of Ras in both serum and platelet-derived growth factor (PDGF). FTS (7.5-20 micromol/L) potently inhibited PDGF-induced HMC proliferation but had no effect on serum-induced proliferation. FTS (10-20 micromol/L) inhibited both Ras and phospho-MAPK activation by serum and PDGF. Furthermore, FTS (10-20 micromol/L) increased HMC apoptosis in the presence of PDGF but not in serum. Moreover, PDGF-stimulated activation of the survival protein Akt was inhibited by FTS. In contrast, serum-stimulated activation of Akt was unaffected by FTS. CONCLUSION FTS (5-20 micromol/L) inhibits PDGF-induced but not serum-induced HMC proliferation. FTS (10-20 micromol/L) also promotes HMC apoptosis in the presence of PDGF but not serum. These effects appear to be mediated by inhibitory effects on Ras-dependent signaling that occur as a result of the dislodgment of Ras from its membrane-anchorage sites by FTS. The selectivity of FTS toward PDGF-driven HMC proliferation suggests that FTS may be a valuable therapeutic in mesangioproliferative renal disease.
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Affiliation(s)
- Arif Khwaja
- Department of Renal Medicine, GKT School of Medicine, King's College London, London, United Kingdom
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Kocher HM, Senkus R, Moorhead J, Al-Nawab M, Patel AG, Benjamin IS, Hendry BM. Expression of Ras GTPase isoforms in normal and diseased pancreas. Pancreatology 2005; 5:205-14. [PMID: 15855817 DOI: 10.1159/000085273] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2004] [Accepted: 07/06/2004] [Indexed: 12/11/2022]
Abstract
BACKGROUND Ki-Ras is well studied in its oncogenic form in relation to pancreatic pathologies. However, the individual contribution of each of the wild-type Ras isoforms (Ha-, Ki-, and N-) in pancreatic cells in health and disease is unknown. METHODS Archival formalin-fixed, paraffin-embedded specimens of normal (n = 6) and malignant pancreas (n = 35) were used for immuno-histochemical detection of Ras isoforms using a modified polymer system. In addition, immunogold labelling for Ras isoforms was done for subcellular localisation under electron microscopy. RESULTS Pancreatic ductal cells expressed Ha-Ras in the cytoplasm, with Ki-Ras in the apical region and N-Ras (50% of cases) in a supranuclear distribution. Pancreatic acinar cells express all three isoforms with some nuclear expression of Ki-Ras and supranuclear expression of N-Ras. Islets show Ki- and Ha-Ras mainly with differential expression of Ha-Ras (beta cells showing less Ha-Ras and more Ki-Ras than alpha cells). Electron microscopy shows that Ha-Ras is mainly localised in the endoplasmic reticulum and Golgi apparatus of the acinar cells with some plasma membrane localisation of Ki-Ras in the ductal cells. There was no change in any of the Ras isoform expression in the ductal or acinar cells in various malignancies studied (Mann-Whitney U test, p > 0.1). CONCLUSIONS Ras isoforms have distinct and separate cellular and subcellular distribution that may persist even in the malignantly transformed state. Understanding this distinct functional distribution patterns in detail is an essential step if mutant Ki-Ras is to be targeted in the pancreas by genetic or molecular therapeutic tools.
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Affiliation(s)
- Hemant M Kocher
- Department of Surgery, King's College Hospital, Guy's King's and St Thomas' School of Medicine, King's College London, London, UK
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Kocher HM, Senkus R, Al-Nawab M, Hendry BM. Subcellular distribution of Ras GTPase isoforms in normal human kidney. Nephrol Dial Transplant 2005; 20:886-91. [PMID: 15741206 DOI: 10.1093/ndt/gfh744] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Ras GTPase isoforms have been implicated in proliferative renal disease and are known to have differential cellular expression in kidney. However, their exact subcellular location in various cells is unknown. METHODS Immunogold labelling for Ras isoforms (Harvey, Kirsten and Neural) was performed for subcellular localization under electron microscopy in fresh normal kidney specimens, obtained from the opposite pole of kidneys removed for renal cell cancer. RESULTS There was prominent staining shown by Ha-Ras only on the glomerular foot processes as compared with basement membrane or the endothelial cells. Mesangial cells showed intense staining in the cytosol with Ha-Ras (absent in the nucleus), minimal staining with Ki-Ras and none with N-Ras. In both the proximal and distal convoluted tubules, there was a clear staining of the mitochondria with Ha-Ras, with mild cytosolic staining with all of the isoforms. CONCLUSIONS Ras isoforms have distinct and separate subcellular distributions in normal kidney cells. Understanding the functional aspects of this distribution pattern is essential if Ras is to be targeted by genetic or molecular therapeutic tools.
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Affiliation(s)
- Hemant M Kocher
- Department of Health National Clinician Scientist, Tumour Biology Laboratory, Cancer Research UK Clinical Centre Queen Mary's School of Medicine & Dentistry at Barts & The London, John Vane Science Centre, London, UK.
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Clarke HC, Kocher HM, Khwaja A, Kloog Y, Cook HT, Hendry BM. Ras antagonist farnesylthiosalicylic acid (FTS) reduces glomerular cellular proliferation and macrophage number in rat thy-1 nephritis. J Am Soc Nephrol 2003; 14:848-54. [PMID: 12660318 DOI: 10.1097/01.asn.0000057543.55318.8b] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Targeting the Ras family of monomeric GTPases has been suggested as a therapeutic strategy in proliferative renal diseases. This article reports the effects of Ras antagonist farnesylthiosalicylic acid (FTS) in rat thy-1 nephritis, a model in which cytokine-driven glomerular cell proliferation and invasion is likely to involve Ras signaling pathways. FTS in vitro specifically inhibits the binding of Ras to discrete membrane sites, thereby downregulating several Ras-dependent signaling functions and accelerating Ras degradation. Forty-four Lewis rats were given nephritis by day zero injection of a monoclonal thy-1 antibody ER4 (2.5mg/kg body wt). Twenty-two rats were then treated with daily intraperitoneal injection of FTS (5 mg/kg body wt) until sacrifice, and the remaining control rats were given vehicle alone (C). Six rats from each group were sacrificed at day 1 to establish equal injury; other sacrifice points were day 7 and day 10. Bromo-deoxyuridine (BrdU) was injected 1 h before sacrifice, after which sections were used for immunohistochemistry, which included detection of Ras expression, BrdU+ cells and macrophages/monocytes (ED1+). Thy-1 nephritis was associated with an increase in glomerular expression of Ki-Ras and N-Ras isoforms, which was almost fully prevented by FTS. FTS treatment was associated with: (a) a 54% reduction in the mean number of BrdU+ cells per glomerulus (P < 0.01), (b) a 50% reduction in macrophages/monocytes (ED1+) per glomerulus (P < 0.01), and (c) a reduction in 24-h proteinuria at day 10 (P < 0.05). These results show that Ras inhibition can reduce both glomerular cell proliferation and glomerular macrophage cell number in the thy-1 model and justify further study of FTS as a potential therapeutic in proliferative nephritis.
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Affiliation(s)
- Helen C Clarke
- Renal Medicine, GKT School of Medicine, King's College, London, England
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O'Donnell MP. Renal tubulointerstitial fibrosis. New thoughts on its development and progression. Postgrad Med 2000; 108:159-62, 165, 171-2. [PMID: 10914125 DOI: 10.3810/pgm.2000.07.1155] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Current investigation of the pathogenesis of tubulointerstitial injury indicates that both interstitial fibroblasts and renal tubular epithelial cells promote extracellular matrix accumulation. Moreover, two peptides--TGF-beta and angiotensin II--produced locally or delivered in the circulation, appear to play a central role in renal fibrosis. Pharmacologic amelioration of renal fibrosis may require methods directed at multiple factors involved in the fibrotic process, including angiotensin II, TGF-beta, and the proliferation and activation of interstitial fibroblasts.
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Affiliation(s)
- M P O'Donnell
- Department of Medicine, Hennepin County Medical Center, Minneapolis, USA.
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