scholarly journals Rhubarb and Astragalus Capsule Attenuates Renal Interstitial Fibrosis in Rats with Unilateral Ureteral Obstruction by Alleviating Apoptosis through Regulating Transforming Growth Factor beta1 (TGF-β1)/p38 Mitogen-Activated Protein Kinases (p38 MAPK) Pathway

2020 ◽  
Vol 26 ◽  
Author(s):  
Xian Zeng ◽  
Guozhen Cai ◽  
Taolin Liang ◽  
Qingqing Li ◽  
Yufang Yang ◽  
...  
2006 ◽  
Vol 18 (6) ◽  
pp. 655 ◽  
Author(s):  
Megan J. Wallace ◽  
Alison M. Thiel ◽  
Andrea M. Lines ◽  
Graeme R. Polglase ◽  
Foula Sozo ◽  
...  

Increased fetal lung expansion induces lung growth, cell differentiation and extracellular matrix remodelling, although the mechanisms involved are unknown. Platelet-derived growth factor (PDGF)-B, vascular endothelial growth factor (VEGF) and insulin-like growth factor (IGF)-II are mitogens activating the mitogen-activated protein kinase (MAPK) pathway, whereas transforming growth factor (TGF)-β1 induces differentiation and extracellular matrix remodelling. In the present study, we investigated the mRNA levels of PDGF-B, VEGF, IGF-II and TGF-β1, as well as active MAPK levels, during increased fetal lung expansion induced by tracheal obstruction (TO) in sheep for 0 (controls), 36 h or 2, 4, or 10 days (n = 5 in each group). The 3.7-kb VEGF transcript increased by 30% (P < 0.05) at 36 h TO. The expression of PDGF-B decreased by approximately 25% (P < 0.01) at 2–10 days TO. In contrast, TGF-β1 mRNA increased by 96% (P < 0.05) at 10 days TO, when bioactive TGF-β1 decreased by 55% (P < 0.05). Insulin-like growth factor-II mRNA tended to increase at 10 days TO (37% above controls; P = 0.07), whereas mRNA for its receptor, IGF1R, was reduced by TO. There was no change in active MAPK levels preceding or at the time of a TO-induced 800% increase in cell proliferation. We conclude that VEGF is likely to promote expansion-induced endothelial cell proliferation, but the mechanisms underlying expansion-induced proliferation of fibroblasts and alveolar epithelial cells are unlikely to be mediated by increases in PDGF-B or IGF-II expression or activation of the MAPK pathway.


Endocrinology ◽  
2000 ◽  
Vol 141 (6) ◽  
pp. 2236-2243 ◽  
Author(s):  
Gaby Palmer ◽  
Jerôme Guicheux ◽  
Jean-Philippe Bonjour ◽  
Joseph Caverzasio

Abstract Members of the transforming growth factor (TGF)-β family are important regulators of skeletal development. In this study, we investigated the effect of TGF-β1 on inorganic phosphate (Pi) transport and on expression of the type III Pi carriers Glvr-1 and Ram-1 in murine ATDC5 chondrocytes. TGF-β1 induced a selective, dose- and time-dependent increase in sodium-dependent Pi transport in ATDC5 cells. This response was dependent on RNA and protein synthesis and reflected a change in the maximal rate of the transport system, suggesting that TGF-β1 induces the synthesis of new Pi carriers and their insertion into the plasma membrane. Consistently, Northern blotting analysis showed a dose-dependent increase in Glvr-1 messenger RNA expression in response to TGF-β1, which preceded the maximal stimulation of Pi transport by several hours. Glvr-1 thus likely mediates at least part of the increase in Pi uptake induced by TGF-β1. Ram-1 messenger RNA expression was not affected by TGF-β1. TGF-β1 activated the Smad signaling pathway and the mitogen-activated protein kinases ERK and p38 in ATDC5 cells. Unlike the regulation of Pi transport by receptor tyrosine kinase agonists in osteoblasts, the effect of TGF-β1 on Pi uptake in ATDC5 cells did not involve protein kinase C or mitogen-activated protein kinases, suggesting that a specific, possibly Smad-dependent, signal mediates this response. In conclusion, TGF-β1 stimulates Pi transport and Glvr-1 expression in chondrocytes, suggesting that, like proliferation, differentiation, and matrix synthesis, Pi handling is subject to regulation by TGF-β family members in bone-forming cells.


2006 ◽  
Vol 26 (12) ◽  
pp. 4577-4585 ◽  
Author(s):  
Jingmei Lin ◽  
Sanjeevkumar R. Patel ◽  
Min Wang ◽  
Gregory R. Dressler

ABSTRACT The transforming growth factor β (TGF-β) superfamily, including the bone morphogenetic protein (BMP) and TGF-β/activin A subfamilies, is regulated by secreted proteins able to sequester or present ligands to receptors. KCP is a secreted, cysteine-rich (CR) protein with similarity to mouse Chordin and Xenopus laevis Kielin. KCP is an enhancer of BMP signaling in vertebrates and interacts with BMPs and the BMP type I receptor to promote receptor-ligand interactions. Mice homozygous for a KCP null allele are hypersensitive to developing renal interstitial fibrosis, a disease stimulated by TGF-β but inhibited by BMP7. In this report, the effects of KCP on TGF-β/activin A signaling are examined. In contrast to the enhancing effect on BMPs, KCP inhibits both activin A- and TGF-β1-mediated signaling through the Smad2/3 pathway. These inhibitory effects of KCP are mediated in a paracrine manner, suggesting that direct binding of KCP to TGF-β1 or activin A can block the interactions with prospective receptors. Consistent with this inhibitory effect, primary renal epithelial cells from KCP mutant cells are hypersensitive to TGF-β and exhibit increased apoptosis, dissociation of cadherin-based cell junctions, and expression of smooth muscle actin. Furthermore, KCP null animals show elevated levels of phosphorylated Smad2 after renal injury. The ability to enhance BMP signaling while suppressing TGF-β activation indicates a critical role for KCP in modulating the responses between these anti- and profibrotic cytokines in the initiation and progression of renal interstitial fibrosis.


2021 ◽  
Vol 22 (6) ◽  
pp. 2952
Author(s):  
Tzu-Yu Hou ◽  
Shi-Bei Wu ◽  
Hui-Chuan Kau ◽  
Chieh-Chih Tsai

Transforming growth factor-β1 (TGF-β1)-induced myofibroblast transdifferentiation from orbital fibroblasts is known to dominate tissue remodeling and fibrosis in Graves’ ophthalmopathy (GO). However, the signaling pathways through which TGF-β1 activates Graves’ orbital fibroblasts remain unclear. This study investigated the role of the mitogen-activated protein kinase (MAPK) pathway in TGF-β1-induced myofibroblast transdifferentiation in human Graves’ orbital fibroblasts. The MAPK pathway was assessed by measuring the phosphorylation of p38, c-Jun N-terminal kinase (JNK), and extracellular-signal-regulated kinase (ERK) by Western blots. The expression of connective tissue growth factor (CTGF), α-smooth muscle actin (α-SMA), and fibronectin representing fibrogenesis was estimated. The activities of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) responsible for extracellular matrix (ECM) metabolism were analyzed. Specific pharmacologic kinase inhibitors were used to confirm the involvement of the MAPK pathway. After treatment with TGF-β1, the phosphorylation levels of p38 and JNK, but not ERK, were increased. CTGF, α-SMA, and fibronectin, as well as TIMP-1 and TIMP-3, were upregulated, whereas the activities of MMP-2/-9 were inhibited. The effects of TGF-β1 on the expression of these factors were eliminated by p38 and JNK inhibitors. The results suggested that TGF-β1 could induce myofibroblast transdifferentiation in human Graves’ orbital fibroblasts through the p38 and JNK pathways.


Endocrinology ◽  
2009 ◽  
Vol 150 (2) ◽  
pp. 727-740 ◽  
Author(s):  
Yu-Lin Yang ◽  
Yi-Shiuan Liu ◽  
Lea-Yea Chuang ◽  
Jinn-Yuh Guh ◽  
Tao-Chen Lee ◽  
...  

TGF-β is a therapeutic target for renal fibrosis. Scientists have long sought ways to antagonize TGF-β to ameliorate diabetic nephropathy. Bone morphogenetic protein (BMP-2) is a member of the TGF-β superfamily and is highly regulated in the kidney. Thus, the role of BMP-2 was investigated in NRK-49F cells (rat fibroblasts). We showed that TGF-β1 induces an increase in fibronectin. Treatment with exogenous BMP-2 or pCMV-BMP-2 significantly reversed the TGF-β1-induced increase in fibronectin concomitant with a significant decrease in type I TGF-β receptors (TGF-β RI). Moreover, BMP-2 significantly shortened the half-life of TGF-β RI. These results are related to proteosomal activation because MG132, a proteasome inhibitor, abolished BMP-2-mediated degradation of TGF-β RI. This was confirmed because BMP-2 time course dependently enhanced the ubiquitination level of TGF-β RI. In addition, Smads would seem to be involved in the interaction of BMP-2 and TGF-β. We demonstrated that BMP-2 significantly reversed the TGF-β1-induced increase in pSmad2/3 and reversed the TGF-β1-induced decrease in inhibitory Smad7. Most importantly, Smad7 small interfering RNA abolished the BMP-2-induced decrease in TGF-β RI. We evaluated the clinical efficacy of BMP-2 using unilateral ureteral obstruction rats. BMP-2 was administered ip for 7 d. In the unilateral ureteral obstruction kidneys, interstitial fibrosis was prominent. However, treatment with BMP-2 dramatically reduced Masson’s trichrome staining (collagen) in the interstitial and tubular areas of the kidneys concomitantly with a reduction in TGF-β RI. These results suggest that BMP-2 acts as a novel fibrosis antagonizing cytokine partly by down-regulating TGF-β RI and Smads. Bone morphogenetic protein-2 can antagonize TGF-β-inducing cellular fibrosis by intervening post-receptors signaling, thus disclosing an application of therapeutical potential against fibrosis disorders.


2019 ◽  
Vol 47 (11) ◽  
pp. 5787-5801
Author(s):  
Yun Xiao ◽  
Zhiwei Zhang ◽  
Yingyu Fu ◽  
Huizhi Shan ◽  
Sini Cui ◽  
...  

Objective To evaluate the effect of GSTA3 within the PI3K–Keap1/Nrf2 pathway in renal interstitial fibrosis (RIF). Methods An in vitro RIF model with TGF-β1 stimulation in NRK-52E cells was established to identify potential signaling pathways that modulate GSTA3. Changes in GSTA3 expression were observed in the RIF model after silencing or enhancing Nrf2 expression. Changes in GSTA3, Keap1, and Nrf2 expression were detected after blocking the upstream of the Keap1/Nrf2 signaling pathway (including MAPK and PI3K/Akt). The effect of Nrf2 on GSTA3 expression was evaluated by overexpressing Nrf2. Results Protein and mRNA levels of GSTA3, FN, Nrf2, and Keap1 were significantly increased after TGF-β1 stimulation. GSTA3 was also upregulated following overexpression of Nrf2. TGF-β1 activated the PI3K/Akt signaling pathway, leading to RIF. After blocking this pathway, the production of superoxide dismutase, reactive oxygen species, and fibronectin were reduced. The MAPK pathway was not involved in the development of RIF via regulating GSTA3 expression. Conclusions The PI3K–KEAP1/Nrf2–GSTA3 signaling pathway is a possible mechanism of resisting external stimulation of renal fibrosis factors, regulating oxidative stress, and preventing RIF.


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