Nrf2/ARE pathway attenuates oxidative and apoptotic response in human osteoarthritis chondrocytes by activating ERK1/2/ELK1-P70S6K-P90RSK signaling axis.
Humans; *Apoptosis; *Apoptosis; *ERK1/2; *Nrf2; *Osteoarthritis; *Redox; Oxidative Stress; Osteoarthritis/*metabolism; NF-E2-Related Factor 2/genetics/*metabolism; Up-Regulation; MAP Kinase Signaling System; Chondrocytes/*physiology; Caspases/metabolism; Cells; Cultured; 70-kDa/metabolism; Ribosomal Protein S6 Kinases; Carboxylic Ester Hydrolases/metabolism; ets-Domain Protein Elk-1/metabolism; Interleukin-1beta/immunology; 90-kDa/metabolism
Nrf2, a redox regulated transcription factor, has recently been shown to play a role in cartilage integrity but the mechanism remains largely unknown. Osteoarthritis (OA) is a multifactorial disease in which focal degradation of cartilage occurs. Here, we studied whether Nrf2 exerts chondroprotective effects by suppressing the oxidative stress and apoptosis in IL-1beta stimulated human OA chondrocytes. Expression of Nrf2 and its target genes HO-1, NQO1 and SOD2 was significantly high in OA cartilage compared to normal cartilage and was also higher in damaged area compared to smooth area of OA cartilage of the same patient. Human chondrocytes treated with IL-1beta resulted in robust Nrf2/ARE reporter activity, which was inhibited by pretreatment with antioxidants indicating that Nrf2 activity was due to IL-1beta-induced ROS generation. Ectopic expression of Nrf2 significantly suppressed the IL-1beta-induced generation of ROS while Nrf2 knockdown significantly increased the basal as well as
Khan Nazir M; Ahmad Imran; Haqqi Tariq M
Free radical biology & medicine
2018
2018-02
<a href="http://doi.org/10.1016/j.freeradbiomed.2018.01.013" target="_blank" rel="noreferrer noopener">10.1016/j.freeradbiomed.2018.01.013</a>
miR-139 modulates MCPIP1/IL-6 expression and induces apoptosis in human OA chondrocytes.
*Apoptosis; 3' Untranslated Regions; Aged; Chondrocytes/*metabolism/pathology; Down-Regulation; Female; Gene Expression Regulation; Humans; Interleukin-6/*genetics; Male; Messenger/genetics; MicroRNAs/*genetics; Middle Aged; Osteoarthritis/*genetics/pathology; Ribonucleases/*genetics; RNA; Transcription Factors/*genetics; Up-Regulation
IL-6 is an inflammatory cytokine and its overexpression plays an important role in osteoarthritis (OA) pathogenesis. Expression of IL-6 is regulated post-transcriptionally by MCPIP1. The 3' untranslated region (UTR) of MCPIP1 mRNA harbors a miR-139 'seed sequence', therefore we examined the post-transcriptional regulation of MCPIP1 by miR-139 and its impact on IL-6 expression in OA chondrocytes. Expression of miR-139 was found to be high in the damaged portion of the OA cartilage compared with unaffected cartilage from the same patient and was also induced by IL-1beta in OA chondrocytes. Inhibition of miR-139 decreased the expression of IL-6 mRNA by 38% and of secreted IL-6 protein by 40%. However, overexpression of miR-139 increased the expression of IL-6 mRNA by 36% and of secreted IL-6 protein by 56%. These data correlated with altered expression profile of MCPIP1 in transfected chondrocytes. Studies with a luciferase reporter construct confirmed the interactions of miR-139 with the 'seed sequence' located in the 3' UTR of MCPIP mRNA. Furthermore, miR-139 overexpression increased the catabolic gene expression but expression of anabolic markers remained unchanged. Overexpression of miR-139 also induced apoptosis in OA chondrocytes. Importantly, we also discovered that IL-6 is a potent inducer of miR-139 expression in OA chondrocytes. These findings indicate that miR-139 functions as a post-transcriptional regulator of MCPIP1 expression and enhances IL-6 expression, which further upregulates miR-139 expression in OA chondrocytes. These results support our hypothesis that miR-139-mediated downregulation of MCPIP1 promotes
Makki Mohammad Shahidul; Haqqi Tariq M
Experimental & molecular medicine
2015
2015-10
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1038/emm.2015.66" target="_blank" rel="noreferrer noopener">10.1038/emm.2015.66</a>
AMP-activated kinase "Keaps" ischemia/reperfusion-induced necroptosis under control.
*AMP-Activated Protein Kinases; *AMPK; *Apoptosis; *Ischemia/reperfusion; *Myocardium; *Necroptosis; *Necrosis; Apoptosis; Humans; Myocardial Reperfusion Injury; Myocardium
Kanugula Anantha K; Thodeti Charles K
International journal of cardiology
2018
2018-05
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1016/j.ijcard.2018.02.053" target="_blank" rel="noreferrer noopener">10.1016/j.ijcard.2018.02.053</a>
Nrf2/ARE pathway attenuates oxidative and apoptotic response in human osteoarthritis chondrocytes by activating ERK1/2/ELK1-P70S6K-P90RSK signaling axis.
*Apoptosis; *ERK1/2; *Nrf2; *Osteoarthritis; *Redox
Nrf2, a redox regulated transcription factor, has recently been shown to play a role in cartilage integrity but the mechanism remains largely unknown. Osteoarthritis (OA) is a multifactorial disease in which focal degradation of cartilage occurs. Here, we studied whether Nrf2 exerts chondroprotective effects by suppressing the oxidative stress and apoptosis in IL-1beta stimulated human OA chondrocytes. Expression of Nrf2 and its target genes HO-1, NQO1 and SOD2 was significantly high in OA cartilage compared to normal cartilage and was also higher in damaged area compared to smooth area of OA cartilage of the same patient. Human chondrocytes treated with IL-1beta resulted in robust Nrf2/ARE reporter activity, which was inhibited by pretreatment with antioxidants indicating that Nrf2 activity was due to IL-1beta-induced ROS generation. Ectopic expression of Nrf2 significantly suppressed the IL-1beta-induced generation of ROS while Nrf2 knockdown significantly increased the basal as well as
Khan Nazir M; Ahmad Imran; Haqqi Tariq M
Free radical biology & medicine
2018
2018-02
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1016/j.freeradbiomed.2018.01.013" target="_blank" rel="noreferrer noopener">10.1016/j.freeradbiomed.2018.01.013</a>