Baicalin Protects Human OA Chondrocytes Against IL-1β-Induced Apoptosis and ECM Degradation by Activating Autophagy via MiR-766-3p/AIFM1 Axis.

Osteoarthritis (OA) is one of the most prevalent and degenerative diseases with complicated pathology including articular cartilage degradation, subchondral sclerosis and synovitis. Chondrocytes play a crucial role in maintaining cartilage integrity. Primary chondrocytes were treated with 10 ng/mL IL-1β alone, or pre-treated with 20 μM baicalin for 5 h followed by co-treatment with 20 μM baicalin and 10 ng/mL IL-1β. CCK-8 assay was used to assess cell viability, and cell apoptosis was analyzed by both PI/FITC-Annexin V staining and quantitating apoptosis-related Bcl-2, Bax and cleaved-caspase-3 expression at both protein and mRNA level by Western blotting and qRT-PCR, respectively. Chondrocytes were transfected with miRNA-766-3p mimic and autophagy flux was examined by LC3, Beclin and p62 Western blotting and by Cyto-ID assay to quantify autophagic vacuoles. Baicalin treatment decreased the apoptosis rate and the expressions of pro-apoptotic proteins induced by IL-1β, up-regulated anti-apoptotic Bcl-2 expression, and inhibited the degradation of ECM. Baicalin increased autophagy through up-regulating the autophagy markers Beclin-1 expression and LC3 Ⅱ/LC3 Ⅰ ratio and promoting autophagic flux. Contrarily, autophagy inhibition partially alleviated the beneficial effects of baicalin on ECM synthesis and anti-apoptosis in the chondrocytes treated with L-1β. Furthermore, the differential expressional profiles of miR-766-3p and apoptosis-inducing factor mitochondria-associated 1 (AIFM1) were determined in IL-1β and IL-1β + baicalin-treated chondrocytes, and we confirmed AIFM1 was a target of miR-766-3p. MiR-766-3p overexpression suppressed apoptosis and facilitated autophagy and ECM synthesis in the chondrocytes through decreasing AIFM1. Contrarily, silencing of miR-766-3p inhibited chondrocyte autophagy and promoted apoptosis, and this effect could be reversed by AIFM1 silence. Baicalin protects human OA chondrocytes against IL-1β-induced apoptosis and the degradation of ECM through activating autophagy via miR-766-3p/AIFM1 axis and serves as a potential therapeutic candidate for OA treatment.

Li Z ，Cheng J ，Liu J 《Drug Design Development and Therapy》

Baicalin Ameliorates Cartilage Injury in Rats With Osteoarthritis via Modulating miR-766-3p/AIFM1 Axis.

Liu J ，Zhou H ，Chen J ，Zuo Q ，Liu F ... -  《-》

Epigallocatechin-3-O-gallate promotes extracellular matrix and inhibits inflammation in IL-1β stimulated chondrocytes by the PTEN/miRNA-29b pathway.

Yang D ，Cao G ，Ba X ，Jiang H ... -  《-》

Circ_DHRS3 positively regulates GREM1 expression by competitively targeting miR-183-5p to modulate IL-1β-administered chondrocyte proliferation, apoptosis and ECM degradation.

Osteoarthritis (OA) is a chronic inflammatory disease caused by degenerative changes of articular cartilage, involving in the expression changes of special circular RNAs (circRNAs). This study aimed to explore the role of circ_DHRS3 in OA cell models and provide a potential mechanism. OA cell models were constructed using human chondrocytes with Interleukin-1 beta (IL-1β) treatment. The expression of circ_DHRS3, microRNA (miR)-183-5p and Gremlin 1 (GREM1) mRNA was detected using real-time quantitative polymerase chain reaction (RT-qPCR). Cell proliferation was identified using 3-[4, 5-dimethylthiazol-2-yl]-2, 5 diphenyl tetrazolium bromide (MTT) assay. Cell apoptosis was investigated using flow cytometry assay. The protein levels of proliferation- and apoptosis-related proteins were quantified by western blot. The levels of extracellular matrix (ECM)-associated proteins were quantified by western blot to assess ECM degradation. The relationship between miR-183-5p and circ_DHRS3 or GREM1 was predicted and then verified by dual-luciferase reporter assay. Circ_DHRS3 expression was elevated in OA cartilage tissues and IL-1β-treated chondrocytes. Circ_DHRS3 was resistant to RNase R and Actinomycin D. Circ_DHRS3 knockdown promoted chondrocyte proliferation inhibited by IL-1β, and alleviated IL-1β-induced apoptosis and ECM degradation, which were reversed by the inhibition of miR-183-5p, a target of circ_DHRS3. MiR-183-5p restoration also enhanced IL-1β-blocked cell proliferation, and relieved IL-1β-induced cell apoptosis and ECM degradation, while GREM1 (a target of miR-183-5p) overexpression abolished the effects of miR-183-5p restoration. Moreover, circ_DHRS3 regulated GREM1 expression by targeting miR-183-5p. Circ_DHRS3 mediated IL-1β-administered chondrocyte proliferation, apoptosis and ECM degradation by positively regulating GREM1 expression via competitively targeting miR-183-5p.

Jiang R ，Gao H ，Cong F ，Zhang W ，Song T ，Yu Z ... -  《-》

MiR-33b-3p promotes chondrocyte proliferation and inhibits chondrocyte apoptosis and cartilage ECM degradation by targeting DNMT3A in osteoarthritis.

Osteoarthritis (OA) is a common and frequently-occurring disease in middle-aged and older people. A growing number of studies have shown that microRNAs (miRNAs) are involved in the development of OA. However, the role and mechanism of miR-33b-3p in OA remain ill-defined. The levels of miR-33b-3p and DNA methyltransferase 3A (DNMT3A) mRNA were determined by quantitative real-time polymerase chain reaction (qRT-PCR). The levels of DNMT3A protein, matrix metalloprotein 13 (MMP-13), a disintegrin and metalloproteinase with thrombospondin motif-5 (ADAMTS-5), collagen II, aggrecan, cleaved Caspase-3, B-cell lymphoma-2 (Bcl-2) and BCL2-Associated X (Bax) were measured by Western blot assay. Cell proliferation and cell apoptosis were assessed by Cell Counting Kit-8 (CCK-8) assay and flow cytometry analysis, respectively. The targeting relationship between miR-33b-3p and DNMT3A was verified by dual-luciferase reporter assay. The expression of miR-33b-3p was decreased and the expression of DNMT3A was increased in OA cartilage tissues and IL-1β-induced chondrocytes. There was an inverse correlation between miR-33b-3p and DNMT3A in OA cartilage tissues. MiR-33b-3p overexpression or DNMT3A knockdown inhibited extracellular matrix (ECM) degradation and cell apoptosis and promoted cell proliferation in IL-1β-induced chondrocytes. Moreover, DNMT3A was confirmed to be a direct target of miR-33b-3p. Upregulation of DNMT3A weakened the effects of miR-33b-3p overexpression on cartilage ECM degradation, cell proliferation and apoptosis in IL-1β-activated chondrocytes. MiR-33b-3p overexpression suppressed cartilage ECM degradation and cell apoptosis, and promoted cell proliferation by directly targeting DNMT3A in IL-1β-stimulated chondrocytes.

Ma F ，Li G ，Yu Y ，Xu J ，Wu X ... -  《-》