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Yang YR, Bu FT, Yang Y, Li H, Huang C, Meng XM, Zhang L, Lv XW, Li J. LEFTY2 alleviates hepatic stellate cell activation and liver fibrosis by regulating the TGF-β1/Smad3 pathway. Mol Immunol 2020; 126:31-39. [PMID: 32745796 DOI: 10.1016/j.molimm.2020.07.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 05/23/2020] [Accepted: 07/08/2020] [Indexed: 12/17/2022]
Abstract
Activated hepatic stellate cells (HSCs) are the major cell type involved in the deposition of extracellular matrix (ECM) during the development of hepatic fibrosis. In this study, we revealed that left-right determination factor 2 (LEFTY2), one of the proteins belonging to the transforming growth factor-β (TGF-β) protein superfamily, was remarkedly decreased in human hepatic fibrosis tissues and in a carbon tetrachloride (CCl4)-induced liver fibrosis mouse model. In addition, TGF-β1 treatment markedly reduced the level of LEFTY2 in HSCs. Importantly, overexpression of LEFTY2 suppressed the activation and proliferation of HSCs. LEFTY2 inhibited the expression of TGF-β1-induced fibrosis-associated genes (α-SMA and COL1a1) in human (LX-2) and rat (HSC-T6) HSC cell lines in vitro. Mechanistically, we demonstrated, for the first time, the role of LEFTY2 in inhibiting TGF-β1/Smad3 signaling, suggesting that there is a mutual antagonism between LEFTY2 and TGF-β1/Smad3 signaling during liver fibrosis. Similarly, we observed that LEFTY2 has a negative effect on its downstream genes, including c-MYC, CDK4, and cyclin D1, in liver fibrosis. Collectively, our data strongly indicated that LEFTY2 plays an important role in controlling the proliferation and activation of HSCs in the progression of liver fibrosis and this could be a potential therapeutic target for its treatment.
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Affiliation(s)
- Ya-Ru Yang
- School of Pharmacy, Anhui Medical University, 81 Meishan Road, Hefei, 230032, Anhui, China; Department of Clinical Pharmacology, Second Hospital of Anhui Medical University, 678 Furong Road, Hefei, 230601, Anhui, China
| | - Fang-Tian Bu
- School of Pharmacy, Anhui Medical University, 81 Meishan Road, Hefei, 230032, Anhui, China
| | - Yang Yang
- School of Pharmacy, Anhui Medical University, 81 Meishan Road, Hefei, 230032, Anhui, China
| | - Hao Li
- School of Pharmacy, Anhui Medical University, 81 Meishan Road, Hefei, 230032, Anhui, China
| | - Cheng Huang
- School of Pharmacy, Anhui Medical University, 81 Meishan Road, Hefei, 230032, Anhui, China
| | - Xiao-Ming Meng
- School of Pharmacy, Anhui Medical University, 81 Meishan Road, Hefei, 230032, Anhui, China
| | - Lei Zhang
- School of Pharmacy, Anhui Medical University, 81 Meishan Road, Hefei, 230032, Anhui, China
| | - Xiong-Wen Lv
- School of Pharmacy, Anhui Medical University, 81 Meishan Road, Hefei, 230032, Anhui, China
| | - Jun Li
- School of Pharmacy, Anhui Medical University, 81 Meishan Road, Hefei, 230032, Anhui, China.
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Zhang L, Liu X, Liang J, Wu J, Tan D, Hu W. Lefty-1 inhibits renal epithelial-mesenchymal transition by antagonizing the TGF-β/Smad signaling pathway. J Mol Histol 2020; 51:77-87. [PMID: 32065356 DOI: 10.1007/s10735-020-09859-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2020] [Accepted: 02/04/2020] [Indexed: 12/15/2022]
Abstract
Epithelial-mesenchymal transition (EMT) is a biological process in which tubular epithelial cells lose their phenotypes, and new mesenchymal feature are obtained. In particular, type II EMT possibly contributes to renal tissue fibrogenesis. Recent studies indicate that Lefty-1, a novel member of the TGF-β superfamily with pleiotropical and biological regulation characteristics on TGF-β and other signaling pathways, is considered to have potential fibrotic effects. However, its role in EMT, which is often a long-term consequence of renal tubulointerstitial fibrosis, remains unknown. In this study, we found that Lefty-1 alleviates EMT induction through antagonizing TGF-β/Smad pathway in vivo and in vitro. In unilateral ureteral obstruction (UUO) model mice, administration of adenovirus-mediated overexpression of Lefty-1 (Ad-Lefty-1) significantly reduced TGF-β1/Smad expression and alleviated the phenotypic transition of epithelial cells to mesenchymal cells and extracellular matrix (ECM) accumulation. In high glucose-induced rat renal tubular duct epithelial cell line (NRK-52E), EMT and ECM synthesis were alleviated with Lefty-1 treatment, which significantly inhibited TGF-β1/Smad pathway activation in UUO mice and high glucose-treated NRK-52E cells. Thus, Lefty-1 can alleviate EMT and renal interstitial fibrosis in vivo and in vitro through antagonizing the TGF-β/Smad pathway, and Lefty-1 might have a potential novel therapeutic effect on fibrotic kidney diseases.
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Affiliation(s)
- Lijun Zhang
- Department of Urology, Minda Hospital, Affiliated to Hubei Minzu University, Enshi, 445000, Hubei, China.
| | - Xiaohua Liu
- Department of Urology, Minda Hospital, Affiliated to Hubei Minzu University, Enshi, 445000, Hubei, China
| | - Jun Liang
- Department of Urology, Minda Hospital, Affiliated to Hubei Minzu University, Enshi, 445000, Hubei, China
| | - Jianhua Wu
- Department of Urology, Minda Hospital, Affiliated to Hubei Minzu University, Enshi, 445000, Hubei, China
| | - Daqing Tan
- Department of Urology, Minda Hospital, Affiliated to Hubei Minzu University, Enshi, 445000, Hubei, China
| | - Wei Hu
- Department of Urology, The First Affiliated Hospital of University of South of China, Hengyang, 421001, Hunan, China
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Huang H, Zheng F, Dong X, Wu F, Wu T, Li H. Allicin inhibits tubular epithelial-myofibroblast transdifferentiation under high glucose conditions in vitro. Exp Ther Med 2016; 13:254-262. [PMID: 28123498 DOI: 10.3892/etm.2016.3913] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Accepted: 05/04/2016] [Indexed: 12/16/2022] Open
Abstract
Previous studies have suggested that tubular epithelial-mesenchymal transition (EMT) is an important event in renal tubulointerstitial fibrosis, which is a clinical characteristic of diabetic nephropathy. The present study aimed to investigate the effect of allicin, the major biological active component of garlic, on the EMT of a human renal proximal tubular epithelial cell line (HK-2) cultured under high glucose concentrations. HK-2 cells were exposed for 48 h to 5.5 or 25 mmol/l D-glucose, 25 mmol/l D-glucose plus allicin (2.5, 5, 10 or 20 µg/ml) or 25 mmol/l D-glucose plus 20 µmol/l PD98059, a selective inhibitor of the mitogen activated protein kinase/extracellular signal-regulated kinase (ERK) signaling pathway. The EMT of HK-2 cells was assessed by analyzing the protein expression of E-cadherin, α-smooth muscle actin (α-SMA), vimentin and collagen I via immunocytochemistry. In addition, reverse transcription-quantitative polymerase chain reaction and western blotting were used to detect the expression levels of transforming growth factor (TGF)-β1 and phosphorylated (p)-ERK1/2. Marked morphological changes were observed in HK-2 cells cultured under high glucose conditions, and these changes were abrogated by simultaneous incubation with allicin and PD98059. The expression levels of α-SMA, vimentin and collagen I were significantly increased in HK-2 cells cultured under high glucose conditions, as compared with those cultured under normal glucose conditions (P<0.01). Conversely, the expression levels of E-cadherin were significantly decreased upon stimulation with high glucose (P<0.01). Furthermore, the expression levels of TGF-β1 and p-ERK1/2 were significantly upregulated in HK-2 cells cultured under high glucose conditions, as compared with those cultured under normal glucose conditions (P<0.05). Allicin partially reversed the high-glucose-induced increase in α-SMA, vimentin and collagen I expression (P<0.01 at 20 µg/ml), increased the expression of E-cadherin, and significantly downregulated the high glucose-induced expression of TGF-β1 and p-ERK1/2 in a dose-dependent manner (P<0.05). The results of the present study suggested that high glucose concentrations induced the EMT of HK-2 cells, and that allicin was able to inhibit the EMT, potentially via regulation of the ERK1/2-TGF-β1 signaling pathway.
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Affiliation(s)
- Hong Huang
- Department of Endocrinology, Zhejiang Hospital, Hangzhou, Zhejiang 310013, P.R. China
| | - Fenping Zheng
- Department of Endocrinology, The Affiliated Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310016, P.R. China
| | - Xuehong Dong
- Department of Endocrinology, The Affiliated Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310016, P.R. China
| | - Fang Wu
- Department of Endocrinology, The Affiliated Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310016, P.R. China
| | - Tianfeng Wu
- Department of Endocrinology, Zhejiang Hospital, Hangzhou, Zhejiang 310013, P.R. China
| | - Hong Li
- Department of Endocrinology, The Affiliated Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310016, P.R. China
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4
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Guo HL, Liao XH, Liu Q, Zhang L. Angiotensin II Type 2 Receptor Decreases Transforming Growth Factor-β Type II Receptor Expression and Function in Human Renal Proximal Tubule Cells. PLoS One 2016; 11:e0148696. [PMID: 26867007 PMCID: PMC4750982 DOI: 10.1371/journal.pone.0148696] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 01/20/2016] [Indexed: 01/11/2023] Open
Abstract
Transforming growth factor-β (TGF-β), via its receptors, induces epithelial-mesenchymal transition (EMT) and plays an important role in the development of renal tubulointersitial fibrosis. Angiotensin II type 2 receptor (AT2R), which mediates beneficial renal physiological functions, has received attention as a prospective therapeutic target for renoprotection. In this study, we investigated the effect and underlying mechanism of AT2R on the TGF-β receptor II (TGF-βRII) expression and function in human proximal tubular cells (HK-2). Here, we show that the AT2R agonist CGP42112A decreased TGF-βRII protein expression in a concentration- and time-dependent manner in HK-2 cells. The inhibitory effect of the AT2R on TGF-βRII expression was blocked by the AT2R antagonists PD123319 or PD123177. Stimulation with TGF-β1 enhanced EMT in HK-2 cells, which was prevented by pre-treatment with CGP42112A. One of mechanisms in this regulation is associated with the increased TGF-βRII degradation after activation of AT2R. Furthermore, laser confocal immunofluorescence microscopy showed that AT2R and TGF-βRII colocalized in HK-2 cells. AT2R and TGF-βRII coimmunoprecipitated and this interaction was increased after AT2R agonist stimulation for 30 min. The inhibitory effect of the AT2R on TGF-βRII expression was also blocked by the nitric oxide synthase inhibitor L-NAME, indicating that nitric oxide is involved in the signaling pathway. Taken together, our study indicates that the renal AT2R regulates TGF-βRII expression and function via the nitric oxide pathway, which may be important in the control of renal tubulointerstitial fibrosis.
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MESH Headings
- Cell Line
- Dose-Response Relationship, Drug
- Epithelial-Mesenchymal Transition
- Fibrosis/pathology
- Humans
- Imidazoles/chemistry
- Kidney/pathology
- Kidney Tubules, Proximal/cytology
- Kidney Tubules, Proximal/pathology
- Microscopy, Confocal
- Microscopy, Fluorescence
- Nitric Oxide/chemistry
- Oligopeptides/chemistry
- Protein Serine-Threonine Kinases/genetics
- Protein Serine-Threonine Kinases/metabolism
- Pyridines/chemistry
- Receptor, Angiotensin, Type 2/metabolism
- Receptor, Angiotensin, Type 2/physiology
- Receptor, Transforming Growth Factor-beta Type II
- Receptors, Transforming Growth Factor beta/genetics
- Receptors, Transforming Growth Factor beta/metabolism
- Time Factors
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Affiliation(s)
- Hui-Lin Guo
- Department of Nephrology, The Second Affiliated Hospital, Chongqing Medical University, Chongqing, 400010, China
| | - Xiao-Hui Liao
- Department of Nephrology, The Second Affiliated Hospital, Chongqing Medical University, Chongqing, 400010, China
| | - Qi Liu
- Institute for Viral Hepatitis, Key Laboratory of Molecular Biology for Infectious Diseases, The Second Affiliated Hospital, Chongqing Medical University, Chongqing, 400010, China
- * E-mail: (LZ); (QL)
| | - Ling Zhang
- Department of Nephrology, The Second Affiliated Hospital, Chongqing Medical University, Chongqing, 400010, China
- * E-mail: (LZ); (QL)
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Lefty1 alleviates renal tubulointerstitial injury in mice with unilateral ureteral obstruction. Mol Med Rep 2015; 13:901-8. [DOI: 10.3892/mmr.2015.4631] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2014] [Accepted: 08/27/2015] [Indexed: 11/05/2022] Open
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Zhang L, Zhang J, Xu C, Zhou X, Wang W, Zheng R, Hu W, Wu P. Lefty-1 alleviates TGF-β1-induced fibroblast-myofibroblast transdifferentiation in NRK-49F cells. DRUG DESIGN DEVELOPMENT AND THERAPY 2015; 9:4669-78. [PMID: 26316705 PMCID: PMC4544629 DOI: 10.2147/dddt.s86770] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Fibroblast activation and proliferation are important for fibroblast–myofibroblast transdifferentiation, a crucial process in the pathological changes that define renal interstitial fibrosis. The left–right determination factor (Lefty) is an important cytokine of the transforming growth factor (TGF)-β family, with two variants, Lefty-1 and Lefty-2, in mice. Lefty has diverse functions, such as the regulation of embryonic development, the inhibition of TGF-β1 signaling, and the suppression of tumor activity. However, whether Lefty-1 influences fibroblast activation and proliferation, and consequently prevents fibroblast–myofibroblast transdifferentiation, remains unclear. This study aimed to investigate whether Lefty-1 can attenuate TGF-β1-induced fibroblast–myofibroblast transdifferentiation in normal rat kidney interstitial fibroblast cells (NRK-49F), as well as the mechanisms underlying any effects. Results showed that the typical fibroblast cell morphology of NRK-49F cells was altered after TGF-β1 treatment and that Lefty-1 significantly prevented this change in a dose-dependent manner. Further analyses demonstrated decreased proliferating cell nuclear antigen, cyclin D1, collagen I(A1), alpha-smooth muscle actin, and fibronectin expression. Lefty-1 further induced remarkable reductions in TGF-β1-induced Smad3 and mitogen-activated protein kinase-10/c-Jun N-terminal kinase (JNK-3) signaling, and enhanced expression of the antifibrotic factor bone morphogenetic protein (BMP)-5. However, without TGF-β1, Lefty-1 had no effect on Smad3, JNK-3, and BMP-5 activation and fibroblast–myofibroblast transdifferentiation. Taken together, these findings indicate that Lefty-1 can alleviate TGF-β1-mediated activation and the proliferation of fibroblasts. Furthermore, Lefty-1 may prevent fibroblast–myofibroblast transdifferentiation in part via modulations of Smad3, JNK-3, and BMP-5 activities in the TGF-β/BMP signaling pathway.
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Affiliation(s)
- Lijun Zhang
- Department of Urology, Renmin Hospital of Wuhan University, Wuhan, Hubei Province, People's Republic of China
| | - Jie Zhang
- Department of Urology, Renmin Hospital of Wuhan University, Wuhan, Hubei Province, People's Republic of China
| | - Changgeng Xu
- Department of Urology, Renmin Hospital of Wuhan University, Wuhan, Hubei Province, People's Republic of China
| | - Xiangjun Zhou
- Department of Urology, Renmin Hospital of Wuhan University, Wuhan, Hubei Province, People's Republic of China
| | - Wei Wang
- Department of Urology, Renmin Hospital of Wuhan University, Wuhan, Hubei Province, People's Republic of China
| | - Renping Zheng
- Department of Urology, Renmin Hospital of Wuhan University, Wuhan, Hubei Province, People's Republic of China
| | - Wei Hu
- Department of Urology, Renmin Hospital of Wuhan University, Wuhan, Hubei Province, People's Republic of China
| | - Pin Wu
- Department of Urology, Renmin Hospital of Wuhan University, Wuhan, Hubei Province, People's Republic of China
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Slusser A, Bathula CS, Sens DA, Somji S, Sens MA, Zhou XD, Garrett SH. Cadherin expression, vectorial active transport, and metallothionein isoform 3 mediated EMT/MET responses in cultured primary and immortalized human proximal tubule cells. PLoS One 2015; 10:e0120132. [PMID: 25803827 PMCID: PMC4372585 DOI: 10.1371/journal.pone.0120132] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Accepted: 01/19/2015] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Cultures of human proximal tubule cells have been widely utilized to study the role of EMT in renal disease. The goal of this study was to define the role of growth media composition on classic EMT responses, define the expression of E- and N-cadherin, and define the functional epitope of MT-3 that mediates MET in HK-2 cells. METHODS Immunohistochemistry, microdissection, real-time PCR, western blotting, and ELISA were used to define the expression of E- and N-cadherin mRNA and protein in HK-2 and HPT cell cultures. Site-directed mutagenesis, stable transfection, measurement of transepithelial resistance and dome formation were used to define the unique amino acid sequence of MT-3 associated with MET in HK-2 cells. RESULTS It was shown that both E- and N-cadherin mRNA and protein are expressed in the human renal proximal tubule. It was shown, based on the pattern of cadherin expression, connexin expression, vectorial active transport, and transepithelial resistance, that the HK-2 cell line has already undergone many of the early features associated with EMT. It was shown that the unique, six amino acid, C-terminal sequence of MT-3 is required for MT-3 to induce MET in HK-2 cells. CONCLUSIONS The results show that the HK-2 cell line can be an effective model to study later stages in the conversion of the renal epithelial cell to a mesenchymal cell. The HK-2 cell line, transfected with MT-3, may be an effective model to study the process of MET. The study implicates the unique C-terminal sequence of MT-3 in the conversion of HK-2 cells to display an enhanced epithelial phenotype.
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Affiliation(s)
- Andrea Slusser
- Department of Pathology, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, United States of America
| | - Chandra S. Bathula
- Department of Pathology, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, United States of America
| | - Donald A. Sens
- Department of Pathology, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, United States of America
| | - Seema Somji
- Department of Pathology, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, United States of America
| | - Mary Ann Sens
- Department of Pathology, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, United States of America
| | - Xu Dong Zhou
- Department of Pathology, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, United States of America
| | - Scott H. Garrett
- Department of Pathology, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, United States of America
- * E-mail:
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8
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Effects of dexamethasone on the TGF-β1-induced epithelial-to-mesenchymal transition in human peritoneal mesothelial cells. J Transl Med 2013; 93:194-206. [PMID: 23207448 DOI: 10.1038/labinvest.2012.166] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The epithelial-to-mesenchymal transition (EMT) is known to have a role in appropriate embryonic development, the physiological response to injury and pathological events such as organ fibrosis and cancer progression. Glucocorticoid (GC), one of the most commonly used anti-inflammatory drugs, inhibits the deposition of extracellular matrix independent of its anti-inflammatory effect. The EMT of human peritoneal mesothelial cells (HPMCs) is a key mechanism of peritoneal fibrosis; however, it has not yet been investigated whether GC imposes any effect on the EMT of HPMCs. To investigate the therapeutic potential of GC on preserving peritoneal membrane function, we studied the effect of dexamethasone (DEXA), a synthetic GC, on the transforming growth factor-β1 (TGF-β1)-induced EMT in HPMCs. As assessed by changes in cell morphology, the expression of epithelial and mesenchymal cell markers (such as E-cadherin, ZO-1 and α-SMA, α-smooth muscle actin) and cell migration, DEXA inhibited the TGF-β1-induced EMT. RU486, a glucocorticoid receptor (GR) antagonist, blocked the effect of DEXA on the TGF-β1-induced EMT. Importantly, DEXA also induced the mesenchymal-to-epithelial transition of TGF-β1-stimulated HPMCs. The beneficial effect of DEXA on the TGF-β1-induced EMT was mediated through the amelioration of ERK and p38 mitogen-activated protein kinase (MAPK) phosphorylation; however, this effect was not related to the TGF-β1-induced activation of Smad2/3 signaling. DEXA inhibited glycogen synthase kinase-3β (GSK-3β) phosphorylation and the Snail upregulation induced by TGF-β1, which were also ameliorated by inhibitors of MAPK. In conclusion, this is the first study demonstrating the protective effect of DEXA on the EMT in TGF-β1-stimulated HPMCs by inhibiting MAPK activation, GSK-3β phosphorylation and Snail upregulation.
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9
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Fragiadaki M, Mason RM. Epithelial-mesenchymal transition in renal fibrosis - evidence for and against. Int J Exp Pathol 2011. [PMID: 21554437 DOI: 10.1111/j.1365-2613.2011.00775.x.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Epithelial to mesenchymal transition (EMT) is a well established biological process in metazoan embryological development. Over the past 15 years, investigators have sought to establish whether EMT also occurs in renal epithelial cells, following kidney injury, and to show that the mesenchymal cells formed could give rise to myofibroblasts which populate the renal interstitium, causing fibrosis within it. There is no doubt that proximal tubular epithelial cells (PTECs) can undergo EMT in vitro in response to TGFβ-1 and other inflammatory stimuli. Moreover, the results of experiments with animal models of renal fibrosis and examination of biopsies from patients with chronic kidney disease have lent support to the hypothesis that EMT occurs in vivo. This review discusses some of the key evidence underlying that idea and summarises recent advances in understanding the molecular mechanism underlying the process. Early experiments using mice which were genetically engineered to mark PTECs with the LacZ gene to trace their fate following kidney injury provided evidence supporting the occurrence of EMT. Recently, however, cell lineage tracking experiments using the red fluorescent protein (RFP) as a high-resolution marker for cells of renal epithelial origin did not replicate this result; the interstitial space following kidney injury was devoid of RFP expressing cells, leading the investigators to reject the renal EMT hypothesis.
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Affiliation(s)
- Maria Fragiadaki
- Imperial College Kidney and Transplant Institute, Imperial College London, Hammersmith Hospital, London, UK
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10
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Fragiadaki M, Mason RM. Epithelial-mesenchymal transition in renal fibrosis - evidence for and against. Int J Exp Pathol 2011; 92:143-50. [PMID: 21554437 DOI: 10.1111/j.1365-2613.2011.00775.x] [Citation(s) in RCA: 132] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Epithelial to mesenchymal transition (EMT) is a well established biological process in metazoan embryological development. Over the past 15 years, investigators have sought to establish whether EMT also occurs in renal epithelial cells, following kidney injury, and to show that the mesenchymal cells formed could give rise to myofibroblasts which populate the renal interstitium, causing fibrosis within it. There is no doubt that proximal tubular epithelial cells (PTECs) can undergo EMT in vitro in response to TGFβ-1 and other inflammatory stimuli. Moreover, the results of experiments with animal models of renal fibrosis and examination of biopsies from patients with chronic kidney disease have lent support to the hypothesis that EMT occurs in vivo. This review discusses some of the key evidence underlying that idea and summarises recent advances in understanding the molecular mechanism underlying the process. Early experiments using mice which were genetically engineered to mark PTECs with the LacZ gene to trace their fate following kidney injury provided evidence supporting the occurrence of EMT. Recently, however, cell lineage tracking experiments using the red fluorescent protein (RFP) as a high-resolution marker for cells of renal epithelial origin did not replicate this result; the interstitial space following kidney injury was devoid of RFP expressing cells, leading the investigators to reject the renal EMT hypothesis.
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Affiliation(s)
- Maria Fragiadaki
- Imperial College Kidney and Transplant Institute, Imperial College London, Hammersmith Hospital, London, UK
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