scholarly journals The Antioxidant tempol delays the MIA-induced osteoarthritis progression in rats via modulation of signaling pathways involving TGF-β1/SMAD3/NOX4 axis

Author(s):  
Hagar B. Abo-zalam ◽  
Rehab F. Abdel-Rahman ◽  
Mohamed F. Abd-Ellah ◽  
Rania M. Abdalsalam ◽  
Mahmoud M. Khattab

Abstract Osteoarthritis (OA) is a complex disease characterized by structural, functional, and metabolic deteriorations of the whole joint and periarticular tissues. In the current study, we aimed to investigate the possible effects of tempol on knee OA induced by the chemical chondrotoxic monosodium iodoacetate (MIA) which closely mimics both the pain and structural changes associated with human OA. Rats were administrated oral tempol (100 mg/kg) one week post-MIA injection (3 mg/ 50 μL saline) at the right knee joints for 21 consecutive days. Tempol improved motor performance and debilitated the MIA-related radiological and histological alterations. Besides, it subsided the knee joint swelling. Tempol decreased the cartilage degradation-related biomarkers as matrix metalloproteinase-13, cartilage oligomeric matrix protein, and fibulin-3. The superoxide dismutase mimetic effect of tempol was accompanied by decreased NADPH oxidase 4 (NOX4), inflammatory mediators, nuclear factor kappa-B (NF-κB), over-released insulin-like growth factor-1 (IGF-1) and transforming growth factor-β1 (TGF-β1). Tempol decreased the expression of chemotactic cytokine ligand 2 (CCL2), dickkopf‑related protein-1 (DKK-1), and protein kinase C (PKC). On the molecular level, tempol reduced the phosphorylated protein levels of p38 mitogen-activated protein kinase (MAPK), phosphoinositide 3-kinase (PI3K), protein kinase B (Akt), and small mother against decapentaplegic 3 homologs (SMAD3). These findings suggest the promising role of tempol in ameliorating MIA-induced knee OA in rats via collateral suppression of the catabolic signaling cascades including TGF-β1/SMAD3/NOX4, NOX4/p38MAPK/NF-κB, and PI3K/Akt/NF-κB and therefore modulation of oxidative stress, catabolic inflammatory cascades, chondrocyte metabolic homeostasis, autophagy, and cell survival.

Molecules ◽  
2021 ◽  
Vol 26 (22) ◽  
pp. 6993
Author(s):  
Hagar B. Abo-zalam ◽  
Rehab F. Abdel-Rahman ◽  
Mohamed F. Abd-Ellah ◽  
Rania M. Abdelsalam ◽  
Mahmoud M. Khattab

Osteoarthritis (OA) is a complex disease characterized by structural, functional, and metabolic deteriorations of the whole joint and periarticular tissues. In the current study, we aimed to investigate the possible effects of tempol on knee OA induced by the chemical chondrotoxic monosodium iodoacetate (MIA) which closely mimics both the pain and structural changes associated with human OA. Rats were administrated oral tempol (100 mg/kg) one week post-MIA injection (3 mg/50 μL saline) at the right knee joints for 21 consecutive days. Tempol improved motor performance and debilitated the MIA-related radiological and histological alterations. Moreover, it subsided the knee joint swelling. Tempol decreased the cartilage degradation-related biomarkers as matrix metalloproteinase-13, bone alkaline phosphatase (bone ALP), and fibulin-3. The superoxide dismutase mimetic effect of tempol was accompanied by decreased NADPH oxidase 4 (NOX4), inflammatory mediators, nuclear factor-kappa B (NF-κB), over-released transforming growth factor-β1 (TGF-β1). Tempol decreased the expression of chemokine (C-C motif) ligand 2 (CCL2). On the molecular level, tempol reduced the phosphorylated protein levels of p38 mitogen-activated protein kinase (MAPK), and small mother against decapentaplegic 3 homologs (SMAD3). These findings suggest the promising role of tempol in ameliorating MIA-induced knee OA in rats via collateral suppression of the catabolic signaling cascades including TGF-β1/SMAD3/NOX4, and NOX4/p38MAPK/NF-κB and therefore modulation of oxidative stress, catabolic inflammatory cascades, chondrocyte metabolic homeostasis.


2007 ◽  
Vol 81 (12) ◽  
pp. 6412-6418 ◽  
Author(s):  
Veerasamy Ravichandran ◽  
Peter N. Jensen ◽  
Eugene O. Major

ABSTRACT The multiplication of the human neurotropic polyomavirus JC virus (JCV) is regulated by cell membrane receptors and nuclear transcription factors. Signaling pathways also play a role in determining the extent to which JCV can productively infect cells. These data show that constitutively active MEK1 protein (CA-MEK1), overexpressed in cultures of human glia, supports a substantial increase in late JCV protein (Vp-1) synthesis. The specificity of this pathway was indicated by no significant enhancement of JCV multiplication through activation of other components of mitogen-activated protein kinase pathways such as p38, Jun N-terminal protein kinase, and protein kinase A. Further evidence supporting the importance of signaling in JCV infection came from addition of transforming growth factor β1 (TGF-β1), which stimulated a 200% increase of Vp-1 expression. Specific MEK1/2 inhibitors, flavenoid PD98059 and U0126, decreased the basal and TGF-β1-stimulated Vp-1 expression by 95% or more. TGF-β1 is known to phosphorylate/activate Smad DNA binding proteins that could subsequently bind or increase binding to JCV promoter sequences, linking the effects of signaling with JCV transcriptional regulation. The effectiveness with which MEK1/2 inhibitors block JCV multiplication provides insight that may contribute to development of compounds directed against JCV.


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.


2009 ◽  
Vol 20 (3) ◽  
pp. 1020-1029 ◽  
Author(s):  
Wei Zuo ◽  
Ye-Guang Chen

Transforming growth factor (TGF)-β regulates a spectrum of cellular events, including cell proliferation, differentiation, and migration. In addition to the canonical Smad pathway, TGF-β can also activate mitogen-activated protein kinase (MAPK), phosphatidylinositol 3-kinase (PI3K)/Akt, and small GTPases in a cell-specific manner. Here, we report that cholesterol depletion interfered with TGF-β–induced epithelial-mesenchymal transition (EMT) and cell migration. This interference is due to impaired activation of MAPK mediated by cholesterol-rich lipid rafts. Cholesterol-depleting agents specifically inhibited TGF-β–induced activation of extracellular signal-regulated kinase (ERK) and p38, but not Smad2/3 or Akt. Activation of ERK or p38 is required for both TGF-β–induced EMT and cell migration, whereas PI3K/Akt is necessary only for TGF-β–promoted cell migration but not for EMT. Although receptor heterocomplexes could be formed in both lipid raft and nonraft membrane compartments in response to TGF-β, receptor localization in lipid rafts, but not in clathrin-coated pits, is important for TGF-β–induced MAPK activation. Requirement of lipid rafts for MAPK activation was further confirmed by specific targeting of the intracellular domain of TGF-β type I receptor to different membrane locations. Together, our findings establish a novel link between cholesterol and EMT and cell migration, that is, cholesterol-rich lipid rafts are required for TGF-β–mediated MAPK activation, an event necessary for TGF-β–directed epithelial plasticity.


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