Overexpression of matrix metalloproteinase-2 mediates phenotypic transformation of lens epithelial cells

2001 ◽  
Vol 358 (1) ◽  
pp. 41-48 ◽  
Author(s):  
Young SEOMUN ◽  
Jeong-a KIM ◽  
Eunjoo H. LEE ◽  
Choun-Ki JOO

Transforming growth factor-β (TGF-β) is known to be a causative factor in pathological fibrosis and the metastasis of cancer cells, through effects on molecules of the extracellular matrix (ECM). We evaluated the influence of TGF-β1 on the gene expression of matrix metalloproteinase-2 (MMP-2) in lens epithelial cells (LECs). The results showed that TGF-β1 induced the expression of mRNA for MMP-2 in LECs. Subsequently, in order to examine the role of MMP-2, we overexpressed MMP-2 in LECs by stable transfection. The MMP-2-overexpressing LECs showed typical indicators of a myofibroblast-like cell phenotype, such as multiple layers of cells, elongated morphology, and expression of α-smooth muscle actin. We also showed that an MMP inhibitor blocked the TGF-β1-induced morphological change in LECs. These results demonstrate that MMP-2 plays a role in the transformation of LECs, which has implications for the pathological fibrosis of these cells.

2008 ◽  
Vol 294 (3) ◽  
pp. C842-C855 ◽  
Author(s):  
Eri Kubo ◽  
Nigar Fatma ◽  
Yoshio Akagi ◽  
David R. Beier ◽  
Sanjay P. Singh ◽  
...  

A diminished level of endogenous antioxidant in cells/tissues is associated with reduced resistance to oxidative stress. Peroxiredoxin 6 (PRDX6), a protective molecule, regulates gene expression/function by controlling reactive oxygen species (ROS) levels. Using PRDX6 protein linked to TAT, the transduction domain from human immunodeficiency virus type 1 TAT protein, we demonstrated that PRDX6 was transduced into lens epithelial cells derived from rat or mouse lenses. The protein was biologically active, negatively regulating apoptosis and delaying progression of cataractogenesis by attenuating deleterious signaling. Lens epithelial cells from cataractous lenses bore elevated levels of ROS and were susceptible to oxidative stress. These cells harbored increased levels of active transforming growth factor (TGF)-β1 and of α-smooth muscle actin and βig-h3, markers for cataractogenesis. Importantly, cataractous lenses showed a 10-fold reduction in PRDX6 expression, whereas TGF-β1 mRNA and protein levels were elevated. The changes were reversed, and cataractogenesis was delayed when PRDX6 was supplied. Results suggest that delivery of PRDX6 can postpone cataractogenesis, and this should be an effective approach to delaying cataracts and other degenerative diseases that are associated with increased ROS.


2021 ◽  
Vol 478 (12) ◽  
pp. 2285-2296
Author(s):  
Mi-Hyun Nam ◽  
Mina B. Pantcheva ◽  
Johanna Rankenberg ◽  
Ram H. Nagaraj

Transforming growth factor-β2 (TGFβ2)-mediated epithelial to mesenchymal transition (EMT) in lens epithelial cells (LECs) has been implicated in fibrosis associated with secondary cataracts. In this study, we investigated whether the receptor for advanced glycation end products (RAGE) plays a role in TGFβ2-mediated EMT in LECs. Unlike in the LECs from wild-type mice, TGFβ2 failed to elicit an EMT response in LECs from RAGE knockout mice. The lack of RAGE also diminished TGFβ2-mediated Smad signaling. In addition, treatment with TGFβ2 increased IL-6 levels in LECs from wild-type mice but not in those from RAGE knockout mice. Treatment of human LECs with the RAGE inhibitor FPS-ZM1 reduced TGFβ2-mediated Smad signaling and the EMT response. Unlike that in wild-type lenses, the removal of fiber cell tissue in RAGE knockout lenses did not result in elevated levels of α-smooth muscle actin (α-SMA), fibronectin (FN), and integrin β1 in capsule-adherent LECs. Taken together, these results suggest that TGFβ2 signaling is intricately linked to RAGE. Targeting RAGE could be explored as a therapeutic strategy against secondary cataracts.


2008 ◽  
Vol 294 (5) ◽  
pp. F1116-F1128 ◽  
Author(s):  
Gerard Elberg ◽  
Lijuan Chen ◽  
Dorit Elberg ◽  
Michael D. Chan ◽  
Charlotte J. Logan ◽  
...  

Transforming growth factor-β1 (TGF-β1) is known to induce epithelial-mesenchymal transition in the kidney, a process involved in tubulointerstitial fibrosis. We hypothesized that a coactivator of the serum response factor (SRF), megakaryoblastic leukemia factor-1 (MKL1), stimulates α-smooth muscle actin (α-SMA) transcription in primary cultures of renal tubular epithelial cells (RTC), which convert into myofibroblasts on treatment with TGF-β1. Herein, we study the effect of MKL1 expression on α-SMA in these cells. We demonstrate that TGF-β1 stimulation of α-SMA transcription is mediated through CC(A/T)6-rich GG elements known to bind to SRF. These elements also mediate the MKL1 effect that dramatically activates α-SMA transcription in serum-free media. MKL1 fused to green fluorescent protein localizes to the nucleus and induces α-SMA expression regardless of treatment with TGF-β1. Using proteasome inhibitors, we also demonstrate that the proteolytic ubiquitin pathway regulates MKL1 expression. These data indicate that MKL1 overexpression is sufficient to induce α-SMA expression. Inhibition of endogenous expression of MKL1 by small interfering RNA abolishes TGF-β1 stimulation of α-SMA expression. Therefore, MKL1 is also absolutely required for TGF-β1 stimulation of α-SMA expression. Western blot and immunofluorescence analysis show that overexpressed and endogenous MKL1 are located in the nucleus in non-stimulated RTC. Chromatin immunoprecipitation assay demonstrates that TGF-β1 induces binding of endogenous SRF and MKL1 to the α-SMA promoter in chromatin. Since MKL1 constitutes a potent factor regulating α-SMA expression, modulation of endogenous MKL1 expression or activity may have a profound effect on myofibroblast formation and function in the kidney.


Hereditas ◽  
2021 ◽  
Vol 158 (1) ◽  
Author(s):  
Yuebin Wang ◽  
Huike Yang ◽  
Xian Su ◽  
Anqiang Cao ◽  
Feng Chen ◽  
...  

Abstract Background Asthma is a common chronic respiratory disease that influences 300 million people all over the world. However, the pathogenesis of asthma has not been fully elucidated. It has been reported that transforming growth factor-β (TGF-β) can activate myofibroblasts. Moreover, the fibroblast to myofibroblast transformation (FMT) can be triggered by TGF-β, which is a major mediator of subepithelial fibrosis. Secreted modular calcium-binding protein 2 (SMOC2) is a member of cysteine (SPARC) family and is involved in the progression of multiple diseases. However, its role in asthma remains poorly understood. RT-qPCR evaluated the expression of SMOC2. Bromodeoxyuridine assay and wound-healing assay detected the proliferation and migration of lung fibroblasts, respectively. IF staining was performed to assess the expression of α-smooth muscle actin (α-SMA). Western blot analysis detected the levels of proteins. Flow cytometry was utilized for determination of the number of myofibroblasts. Results We found the expression of SMOC2 was upregulated by the treatment of TGF-β1 in lung fibroblasts. In addition, SMOC2 promoted the proliferation and migration of lung fibroblasts. More importantly, SMOC2 accelerated FMT of lung fibroblasts. Furthermore, SMOC2 was verified to control the activation of AKT and ERK. Rescue assays showed that the inhibition of AKT and ERK pathway reversed the promoting effect of SMOC2 overexpression on proliferation, migration and FMT in lung fibroblasts. Conclusions This work demonstrated that SMOC2 modulated TGF-β1-induced proliferation, migration and FMT in lung fibroblasts and may promote asthma, which potentially provided a novel therapeutic target for the management of asthma.


Cardiology ◽  
2017 ◽  
Vol 138 (3) ◽  
pp. 179-185 ◽  
Author(s):  
Sarah M. Lima ◽  
Antonios A. Pitsis ◽  
Timotheos G. Kelpis ◽  
Mohamed H. Shahin ◽  
Taimour Y. Langaee ◽  
...  

Background: It has been suggested that collagen abnormalities of the mitral valve are present in patients with floppy mitral valve (FMV)/mitral valve prolapse (MVP). Genetic factors determining collagen synthesis and degradation have not been well defined in these patients. This study was undertaken to determine whether selective polymorphisms of matrix metalloproteinase-2 (MMP2) or transforming growth factor-β (TGFβ), with known or putative effects on collagen turnover, are more frequent in FMV/MVP. Methods: Single nucleotide polymorphisms (SNPs) in select genes related to collagen turnover, including MMP2 rs2285053, MMP2 rs243865, TGFβ1 rs1800469, and TGFβ2 rs900, were determined in 98 patients with FMV/MVP who had severe mitral regurgitation and compared to 99 controls. Results:MMP2 rs243865 was the only SNP significantly associated with FMV/MVP as compared to the control (odds ratio 2.07, 95% CI 1.23-3.50, p = 0.006). MMP2 rs228503 was the only SNP significantly associated with the FMV/MVP syndrome as compared to patients with FMV/MVP without the syndrome (odds ratio 2.41, 95% CI 1.08-5.40, p = 0.032). Conclusion: The frequency of certain MMP2 polymorphisms is higher in patients with the FMV/MVP syndrome and patients with FMV/MVP without the syndrome. The data suggest that a genetic predisposition that alters collagen turnover may play a role in the pathogenesis and development of FMV/MVP.


2000 ◽  
Vol 350 (1) ◽  
pp. 291-298 ◽  
Author(s):  
David J. GRAINGER ◽  
Emma K. FROW

The cytokine transforming growth factor β1 (TGF-β1) is secreted in a latent form that has no known biological activity. The conversion of latent TGF-β1 into its biologically active 25kDa form is thought to be an important step in the regulation of TGF-β activity both in cell culture and in vivo. Thrombospondin (TSP)-1, a 360kDa platelet α-granule and extracellular matrix protein, has been shown to participate in TGF-β1 activation. We have used a chemically defined system to examine the mechanism of TSP-1-mediated TGF-β1 activation. However, the addition of two different preparations of TSP-1 to recombinant small latent TGF-β1 in the test tube resulted in only a very small increase in the proportion of the TGF-β1 able to bind to the TGF-β type II receptor: from 0.1% to a maximum of 0.4%. This small effect was not specific for TSP-1: matrix metalloproteinase 2, tissue inhibitor of matrix metalloproteinase 2 and active plasminogen activator inhibitor 1, but not transglutaminase, human serum albumin or immunoglobulin, had quantitatively similar effects on latent TGF-β1. Furthermore, no change in the activity associated with small latent TGF-β1 was noted in either mink lung epithelial cell or rat aortic smooth-muscle cell culture systems in the presence of TSP-1 (or TSP-1-derived peptides). We conclude that TSP-1, either alone or in the presence of cultured smooth-muscle cells (a cell type known to activate latent TGF-β in vitro and in vivo) is unable to activate latent TGF-β1. Any TSP-mediated activation of TGF-β1 must depend on additional factor(s) not present in our systems.


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