miR-31-5p/SOX4 Axis Affects Autophagy and Apoptosis of Chondrocytes by Regulating Extracellular Regulated Protein Kinase/Mechanical Target of Rapamycin Kinase Signalling.

Osteoarthritis (OA) is a common type of degenerative joint diseases that is regulated by a combination of complex intercellular signals and modulators, including non-coding RNAs. Mounting evidence suggests that miR-31-5p is physiologically involved in the regulation of chondrocytes, but the mechanism remains unclear. Expression levels of miR-31-5p and SOX4 in OA cartilage tissues and in IL-1β-stimulated chondrocytes were examined by quantification polymerase chain reaction (q-PCR) or immunohistochemistry assays. Cell proliferation and apoptosis were detected by Cell Counting Kit-8 (CCK-8) and flow cytometry assays, respectively. Expression of LC3 was detected using immunofluorescence staining. Expressions of autophagy-related proteins and extracellular regulated protein kinase (ERK)/mechanical target of rapamycin kinase (mTORC1) signal-related proteins were measured by Western blot analysis. Molecular interaction was validated by dual luciferase reporter assay. Downregulation of miR-31-5p and upregulation of SOX4 were observed in both OA patients and OA chondrocytes. Mechanistic experiments revealed that miR-31-5p negatively modulated SOX4 expression by directly targeting its 3'- untranslated region. Moreover, overexpression of miR-31-5p suppressed the activation of mTORC1 in an ERK-dependent manner by inhibiting SOX4. Further functional experiments demonstrated that overexpressing miR-31-5p in OA chondrocytes markedly promoted its proliferation and autophagy while inhibiting apoptosis. However, these effects were abolished by overexpression of SOX4 or treatment with 3BDO, an mTOR activator. These results demonstrated that miR-31-5p enhanced survival and autophagy of OA chondrocytes through inactivation of mTORC1 via directly targeting SOX4, suggesting that miR-31-5p may play a protective role in OA progression.

Xu F ，Lv YM ，Wang HB ，Song YC ... -  《-》

LncRNA PART1 modulates chondrocyte proliferation, apoptosis, and extracellular matrix degradation in osteoarthritis via regulating miR-373-3p/SOX4 axis.

Zhu YJ ，Jiang DM 《-》

SOX4-activated lncRNA MCM3AP-AS1 aggravates osteoarthritis progression by modulating miR-149-5p/Notch1 signaling.

To clarify the expression and underlying network of long non-coding RNA (lncRNA) MCM3AP-AS1 in osteoarthritis (OA). Human articular cartilage samples, OA model rats and IL-1β-treated C28/I2 cells were used in this study. The expression changes of genes and proteins were assessed by real-time quantitative PCR (qRT-PCR) and western blot. Cell viability, apoptosis, autophagy and extracellular matrix (ECM) degradation were assessed by Cell Counting Kit-8 (CCK-8), immunohistochemistry (IHC), flow cytometry, immunofluorescence and western blot assays, respectively. Molecule interactions were validated by dual luciferase and Chromatin immunoprecipitation (ChIP) assays. H&E staining was used to detect the pathological changes of cartilage. MCM3AP-AS1 was upregulated in OA patients and IL-1β-induced chondrocytes. Knockdown of MCM3AP-AS1 enhanced autophagy, while alleviated ECM degradation and cartilage injury. Mechanistically, overexpression of SOX4 boosted the transcription of MCM3AP-AS1. Moreover, MCM3AP-AS1 functioned as a molecular sponge or epigenetic regulator of miR-149-5p to facilitate Notch1 expression. Functional rescue experiments showed that either inhibition of miR-149-5p nor ectopic expression of Notch1 dramatically weakened the biological impacts of MCM3AP-AS1 silencing. These finding demonstrated that SOX4-activated MCM3AP-AS1 aggravated OA progression by modulating autophagy and ECM degradation via targeting miR-149-5p/Notch1 axis. These data supported that inhibition of MCM3AP-AS1 might be a potential treatment strategy of OA.

Xu F ，Hu QF ，Li J ，Shi CJ ，Luo JW ，Tian WC ，Pan LW ... -  《-》

LncRNA SNHG5 promotes chondrocyte proliferation and inhibits apoptosis in osteoarthritis by regulating miR-10a-5p/H3F3B axis.

Jiang H ，Pang H ，Wu P ，Cao Z ，Li Z ，Yang X ... -  《-》

ADSCs increase the autophagy of chondrocytes through decreasing miR-7-5p in Osteoarthritis rats by targeting ATG4A.

Osteoarthritis (OA) is a highly degenerative joint disease, mainly companying with progressive destruction of articular cartilage. Adipose-derived stromal cells (ADSCs) therapy enhances articular cartilage repair, extracellular matrix (ECM) synthesis and attenuates joints inflammation, but specific mechanisms of therapeutic benefit remain poorly understood. This study aimed to clarify the therapeutic effects and mechanisms of ADSCs on cartilage damage in the keen joint of OA rat model. Destabilization of the medial meniscus (DMM) and anterior cruciate ligament transection (ACLT) surgery-induced OA rats were treated with allogeneic ADSCs by intra-articular injections for 6 weeks. The protective effect of ADSCs in vivo was measured using Safranin O and fast green staining, immunofluorescence and western blot analysis. Meanwhile, the miRNA-7-5p (miR-7-5p) expression was assessed by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). The mechanism of increased autophagy with ADSCs addition through decreasing miR-7-5p was revealed using oligonucleotides, and adenovirus in rat chondrocytes. The luciferase reporter assay revealed the molecular role of miR-7-5p and autophagy related 4A (ATG4A). The substrate of mTORC1 pathway: (p-)p70S6 and (p-)S6 in OA models with ADSCs addition were detected by western blotting. The ADSCs treatment repaired the articular cartilage and maintained chondrocytes ECM homeostasis through modulating chondrocytes autophagy in the OA model, indicators of the change of autophagic proteins expression and autophagic flux. Meanwhile, the increased autophagy induced by ADSCs treatment was closely related to the decreased expression of host-derived miR-7-5p, a negative modulator of OA progression. Functional genomics (overexpression of genes) in vitro studies demonstrate the inhibition of host-derived miR-7-5p in mediating the benefit of ADSCs administration in OA model. Then ATG4A was defined as a target gene of miR-7-5p, and the negative relation between miR-7-5p and ATG4A was investigated in the OA model treated with ADSCs. Furthermore, miR-7-5p mediated chondrocyte autophagy by targeting ATG4A in the OA model treated with ADSCs was confirmed with the rescue trial of ATG4A/miR-7-5p overexpression on rat chondrocyte. Finally, the mTORC1 signaling pathways mediated by host-derived miR-7-5p with ADSCs treatment were decreased in OA rats. ADSCs promote the chondrocytes autophagy by decreasing miR-7-5p in articular cartilage by targeting ATG4A and a potential role for ADSCs based therapeutics for preventing of articular cartilage destruction and extracellular matrix (ECM) degradation in OA.

Zhao S ，Liu Y ，Wang J ，Wen Y ，Wu B ，Yang D ，Wang G ，Xiu G ，Ling B ，Du D ，Xu J ... -  《-》