Profibrotic Effects Of TGF-β1 Research Articles

Golgin Subfamily A Member 5 Is Essential for Production of Extracellular Matrix Proteins during TGF-β1-Induced Periodontal Ligament-Fibroblastic Differentiation.

Human periodontal ligament stem cells (hPDLSCs) can be differentiated into periodontal ligament- (PDL-) fibroblastic progenitors by treatment with low concentrations of transforming growth factor beta 1 (TGF-β1). Although much is known about the profibrotic effects of TGF-β1, the molecular mechanisms mediating the activation of fibroblasts in periodontal ligament-fibroblastic differentiation are not well known. Our study was to investigate the mechanism of the fibroblastic process in the periodontal ligament differentiation of hPDLSCs through the discovery of novel markers. One of the monoclonal antibodies previously established through decoy immunization was the anti-LG11 antibody, which recognized Golgi subfamily A member 5 (GOLGA5) as a PDL-fibroblastic progenitor-specific antigen. GOLGA5/LG11 was significantly upregulated in TGF-β1-induced PDL-fibroblastic progenitors and accumulated in the PDL region of the tooth root. GOLGA5 plays a role in vesicle tethering and docking between the endoplasmic reticulum and the Golgi apparatus. siRNA-mediated depletion of endogenous GOLGA5 upregulated in TGF-β1-induced PDL-fibroblastic progenitors resulted in downregulation of representative PDL-fibroblastic markers and upregulation of osteoblast markers. When the TGF-β1 signaling pathway was blocked or GOLGA5 was depleted by siRNA, the levels of extracellular matrix (ECM) proteins, such as type I collagen and fibronectin, decreased in PDL-fibroblastic progenitors. In addition, Golgi structures in the perinuclear region underwent fragmentation under these conditions. These results suggest that GOLGA5/LG11 is a PDL-fibroblastic marker with functional importance in ECM protein production and secretion, which are important processes in PDL-fibroblastic differentiation.

Blockade of TMEM16A protects against renal fibrosis by reducing intracellular Cl- concentration.

Renal fibrosis is the final common outcome in most forms of chronic kidney disease (CKD). However, the underlying causal mechanisms remain obscure. The present study examined whether transmembrane member 16A (TMEM16A), a Ca2+ -activated chloride channel, contributes to the progression of renal fibrosis. Masson staining, western blot and immunohistochemistry were used to measure renal fibrosis and related proteins expression. MQAE was used to evaluate the intracellular Cl- concentration. TMEM16A expression was significantly up-regulated in fibrotic kidneys of unilateral ureteral obstruction (UUO) and high-fat diet murine models and in renal samples of IgA nephropathy patients. In vivo knockdown of TMEM16A with adenovirus harbouring TMEM16A-shRNA or inhibition of TMEM16A channel activity with inhibitors CaCCinh-A01 or T16Ainh-A01 effectively prevented UUO-induced renal fibrosis and decreased protein expression of fibronectin, α-SMA and collagen in the obstructed kidneys. In cultured HK2 cells, knockdown or inhibition of TMEM16A suppressed TGF-β1-induced epithelial-mesenchymal transition, reduced snail1 expression and phosphorylation of Smad2/3 and ERK1/2, whereas overexpression of TMEM16A showed the opposite effects. TGF-β1 increased [Cl- ]i in HK2 cells, which was inhibited by knockdown or inhibition of TMEM16A. Reducing [Cl- ]i significantly blunted TGF-β1-induced Smad2/3 phosphorylation and profibrotic factors expression. The profibrotic effects of TGF-β1 were also reduced by inhibition of serum- and glucocorticoid-inducible protein kinase 1 (SGK1). SGK1 was also suppressed by reducing [Cl- ]i. Blockade of TMEM16A prevented the progression of kidney fibrosis, likely by suppressing [Cl- ]i/SGK1/TGF-β1 signalling pathway. TMEM16A may be a potential new therapeutic target against renal fibrosis.

MiR-150 Promotes Renal Fibrosis in Lupus Nephritis by Downregulating SOCS1

MicroRNAs (miRs) seem to mediate renal fibrosis in several renal diseases, with some miRs having profibrotic effects and others having opposing effects. Although differential expression of certain miRs has been described in lupus nephritis, it is unknown whether miRs contribute to fibrosis or could serve as biomarkers of specific histologic manifestations of lupus nephritis. Here, we compared miR expression in kidney biopsies from patients with lupus nephritis and identified miR-150 as the most differentially expressed miR in kidneys with high chronicity (chronicity index [CI] ≥ 4); miR-150 positively correlated with chronicity scores and the expression of profibrotic proteins. Overexpression of miR-150 significantly reduced expression of the antifibrotic protein suppressor of cytokine signaling 1 (SOCS1) and upregulated profibrotic proteins in both proximal tubular and mesangial cells. Directly targeting SOCS1 with a small interfering RNA produced similar results. Furthermore, TGF-β1 induced miR-150 expression, decreased SOCS1, and increased profibrotic proteins in proximal tubular cells and podocytes; a miR-150 inhibitor reversed these changes, suggesting that the profibrotic effects of TGF-β1 are, at least in part, mediated by miR-150. Consistent with these in vitro observations, biopsies with high miR-150 and high CI exhibited substantial expression of TGF-β1, reduced SOCS1, and an increase in profibrotic proteins. In summary, miR-150 is a promising quantitative renal biomarker of kidney injury in lupus nephritis. Our results suggest that miR-150 promotes renal fibrosis by increasing profibrotic molecules through downregulation of SOCS1.

Association of β-catenin with P-Smad3 but not LEF-1 dissociates in vitro profibrotic from anti-inflammatory effects of TGF-β1

Transforming growth factor β1 (TGF-β1) is known to be both anti-inflammatory and profibrotic. Cross-talk between TGF-β/Smad and Wnt/β-catenin pathways in epithelial-mesenchymal transition (EMT) suggests a specific role for β-catenin in profibrotic effects of TGF-β1. However, no such mechanistic role has been demonstrated for β-catenin in the anti-inflammatory effects of TGF-β1. In the present study, we explored the role of β-catenin in the profibrotic and anti-inflammatory effects of TGF-β1 by using a cytosolic, but not membrane, β-catenin knockdown chimera (F-TrCP-Ecad) and the β-catenin/CBP inhibitor ICG-001. TGF-β1 induced nuclear Smad3/β-catenin complex, but not β-catenin/LEF-1 complex or TOP-flash activity, during EMT of C1.1 (renal tubular epithelial) cells. F-TrCP-Ecad selectively degraded TGF-β1-induced cytoplasmic β-catenin and blocked EMT of C1.1 cells. Both F-TrCP-Ecad and ICG-001 blocked TGF-β1-induced Smad3/β-catenin and Smad reporter activity in C1.1 cells, suggesting that TGF-β1-induced EMT depends on β-catenin binding to Smad3, but not LEF-1 downstream of Smad3, through canonical Wnt. In contrast, in J774 macrophages, the β-catenin level was low and was not changed by interferon-γ (IFN-γ) or lipopolysaccharide (LPS) with or without TGF-β1. TGF-β1 inhibition of LPS-induced TNF-α and IFN-γ-stimulated inducible NO synthase (iNOS) expression was not affected by F-TrCP-Ecad, ICG-001 or by overexpression of wild-type β-catenin in J774 cells. Inhibition of β-catenin by either F-TrCP-Ecad or ICG-001 abolished LiCl-induced TOP-flash, but not TGF-β1-induced Smad reporter, activity in J774 cells. These results demonstrate for the first time that β-catenin is required as a co-factor of Smad in TGF-β1-induced EMT of C1.1 epithelial cells, but not in TGF-β1 inhibition of macrophage activation. Targeting β-catenin may dissociate the TGF-β1 profibrotic and anti-inflammatory effects.

Sorafenib inhibits transforming growth factor β1-Mediated Epithelial-Mesenchymal Transition and apoptosis in mouse hepatocytes

Epithelial-mesenchymal transition (EMT) is a physiological process that has been recognized to occur during the progression of an increasingly large number of human diseases, including liver fibrosis, cirrhosis, and hepatocellular carcinoma. The activation of transforming growth factor β (TGF-β) signaling is considered a critical event during EMT, and efforts have been made to screen small molecules that interfere with the TGF-β signaling pathway during EMT. Here we report the identification of sorafenib, a clinical agent that inhibits TGF-β signaling. When applied to AML12 cells and primary hepatocytes, sorafenib strikingly suppressed TGF-β1-induced EMT and apoptosis. Additionally, sorafenib inhibited TGF-β1-induced signal transducer and activator of transcription 3 phosphorylation. We further present in vitro evidence that sorafenib ameliorates the proapoptotic and profibrotic effects of TGF-β1 in mouse primary hepatocytes, suggesting that this drug exerts a protective effect on hepatocytes and has therapeutic potential for the treatment of liver fibrosis.

Microarray Analysis Reveals Up-Regulation of Retinoic Acid and Hepatocyte Growth Factor Related Signaling Pathways by Pro-Insulin C-Peptide in Kidney Proximal Tubular Cells: Antagonism of the Pro-Fibrotic Effects of TGF-β1

Microarray Analysis Reveals Up-Regulation of Retinoic Acid and Hepatocyte Growth Factor Related Signaling Pathways by Pro-Insulin C-Peptide in Kidney Proximal Tubular Cells: Antagonism of the Pro-Fibrotic Effects of TGF-β1