scholarly journals Mechanism of miR-218-5p in autophagy, apoptosis and oxidative stress in rheumatoid arthritis synovial fibroblasts is mediated by KLF9 and JAK/STAT3 pathways

2021 ◽  
pp. jim-2020-001437
Author(s):  
Ming Chen ◽  
Minghui Li ◽  
Na Zhang ◽  
Wenwen Sun ◽  
Hui Wang ◽  
...  

This study was aimed to investigate the effects of miR-218-5p on the proliferation, apoptosis, autophagy, and oxidative stress of rheumatoid arthritis synovial fibroblasts (RASFs), and the related mechanisms. Quantitative reverse transcription–PCR showed that the expression of miR-218-5p in rheumatoid arthritis synovial tissue was significantly higher than that in healthy synovial tissue. Compared with healthy synovial fibroblasts, miR-218-5p expression was obviously upregulated in RASFs, while KLF9 protein expression was markedly downregulated. Mechanistically, miR-218-5p could directly bind to the 3′ untranslated region of KLF9 to inhibit the expression of KLF9. Additionally, transfection of miR-218-5p small interfering RNA (siRNA) inhibited the proliferation but promoted apoptosis and autophagy of RASFs. Simultaneously, miR-218-5p silencing reduced reactive oxygen species and malondialdehyde levels and increased superoxide dismutase and glutathione peroxidase activity to improve oxidative stress in RASFs. More importantly, the introduction of KLF9 siRNA reversed the effects of miR-218-5p siRNA transfection on RASF proliferation, apoptosis, autophagy, and oxidative stress. What is more, silencing miR-218-5p inhibited the activation of JAK2/STAT3 signaling pathway by targeting KLF9. Collectively, knockdown of miR-218-5p could regulate the proliferation, apoptosis, autophagy and oxidative stress of RASFs by increasing the expression of KLF9 and inhibiting the activation of the JAK2/STAT3 signaling pathway, which may provide a potential target for the mechanism research of RA.

2019 ◽  
Vol 208 (1-2) ◽  
pp. 13-24
Author(s):  
Li-xue Zou ◽  
Ling Yu ◽  
Xun-ming Zhao ◽  
Jun Liu ◽  
Hou-gen Lu ◽  
...  

Objective: The aim of this work was to determine the effect of miR-375 on chondrocyte metabolism and oxidative stress in osteoarthritis (OA) mouse models through the JAK2/STAT3 signaling pathway. Methods: Chondrocytes were divided into control, IL-1β, IL-1β + miR-375 mimic, IL-1β + miR-375 inhibitor, IL-1β + miR-NC (negative control), and IL-1β + miR-375 inhibitor + siJAK2 groups. The chondrocyte proliferation was determined by MTT assay, the superoxide dismutase (SOD) and malondialdehyde (MDA) levels by corresponding kits, and the chondrocyte apoptosis by TUNEL staining. Furthermore, OA mouse models were divided into Sham, OA + miR-NC, and OA + miRNA-375 antagomir groups. The pathological changes were observed, and the expressions of miR-375 and the JAK2/STAT3 pathway were determined by qRT-PCR and Western blotting, respectively. Results: IL-1β-induced chondrocytes had significant increases in miR-375 and MDA, with decreased proliferation and SOD levels, as compared to the control group. Meanwhile, they also exhibited elevated apoptosis, with upregulations of ADAMTS-5 and MMP-13 and downregulations of COL2A1 and ACAN, as well as decreased p-JAK2/JAK2, p-STAT3/STAT3, and Bcl-2/Bax. However, these changes were significantly improved after transfection with miR-375 inhibitor, but transfection with miR-375 mimic resulted in severer exacerbation. Notably, the improvement of miR-375 inhibitor could be abolished by transfection with siJAK2. Furthermore, miR-375 antagomir significantly alleviated OA progression in OA mice in vivo. Conclusion: MiR-375 suppression enhanced the ability of chondrocyte to antagonize the oxidative stress and maintained the homeostasis of extracellular matrix metabolism to protect chondrocytes from OA via activation of the JAK2/STAT3 pathway, indicating that miR-375 is a potential molecular target for OA treatment.


2021 ◽  
Vol 2021 ◽  
pp. 1-13 ◽  
Author(s):  
Shouqian Dai ◽  
Ting Liang ◽  
Xiu Shi ◽  
Zongping Luo ◽  
Huilin Yang

Objective. To evaluate the influence of salvianolic acid B (SAB), an antioxidant derived from Danshen, on intervertebral disc degeneration (IDD) and its possible molecular mechanisms. Methods. Sixty adult rats were randomly grouped (control, IDD, and SAB IDD groups). IDD was induced using needle puncture. The rats received daily administration of SAB (20 mg/kg) in the SAB IDD group while the other two groups received only distilled water. The extent of IDD was evaluated using MRI after 3 and 6 weeks and histology after 6 weeks. Oxidative stress was assessed using the ELISA method. In in vitro experiments, nucleus pulposus cells (NPCs) were treated with H2O2 (100 μM) or SAB+H2O2, and levels of oxidative stress were measured. Cell apoptosis was assessed by flow cytometry, expression levels of Bcl-2, Bax, and cleaved caspase-3 proteins. Cell proliferation rate was assessed by EdU analysis. Pathway involvement was determined by Western blotting while the influence of the pathway on NPCs was explored using the pathway inhibitor AG490. Results. The data demonstrate that SAB attenuated injury-induced IDD and oxidative stress, caused by activation of the JAK2/STAT3 signaling pathway in vivo. Oxidative stress induced by H2O2 was reversed by SAB in vitro. SAB reduced the increased cell apoptosis, cleaved caspase-3 expression, and caspase-3 activity induced by H2O2. Reduced cell proliferation and decreased Bcl-2/Bax ratio induced by H2O2 were rescued by SAB. Additionally, the JAK2/STAT3 pathway was activated by SAB, while AG490 counteracted this effect. Conclusion. The results suggest that SAB protects intervertebral discs from oxidative stress-induced degeneration by enhancing proliferation and attenuating apoptosis via activation of the JAK2/STAT3 signaling pathway.


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