Synovial mesenchymal stem cell-derived exosomal microRNA-320c facilitates cartilage damage repair by targeting ADAM19-dependent Wnt signalling in osteoarthritis rats.

OBJECTIVE: Our previous study revealed that synovial mesenchymal stem cell (SMSC)-derived exosomal microRNA-302c enhanced chondrogenesis by targeting a disintegrin and metalloproteinase 19 (ADAM19) in vitro. This study aimed to validate the potential of SMSC-derived exosomal microRNA-302c for the treatment of osteoarthritis in vivo. METHODS: After 4 weeks of destabilization of the medial meniscus surgery (DMM) to establish an osteoarthritis model, the rats received weekly articular cavity injection of SMSCs with or without GW4869 treatment (exosome inhibitor) or exosomes from SMSCs with or without microRNA-320c overexpression for another 4 weeks. RESULTS: SMSCs and SMSC-derived exosomes reduced the Osteoarthritis Research Society International (OARSI) score, improved cartilage damage repair, suppressed cartilage inflammation, suppressed extracellular matrix (ECM) degradation, and inhibited chondrocyte apoptosis in DMM rats. However, these effects were largely hampered in rats that were injected with GW4869-treated SMSCs. Moreover, exosomes from microRNA-320c-overexpressing SMSCs exerted a better effect than exosomes from negative control SMSCs on decreasing the OARSI score, enhancing cartilage damage repair, suppressing cartilage inflammation, and inhibiting ECM degradation and chondrocyte apoptosis. Mechanistically, exosomes from microRNA-320c-overexpressing SMSCs reduced the levels of ADAM19, as well as ß-catenin and MYC, which are two critical proteins in Wnt signalling. CONCLUSION: SMSC-derived exosomal microRNA-320c suppresses ECM degradation and chondrocyte apoptosis to facilitate cartilage damage repair in osteoarthritis rats by targeting ADAM19-dependent Wnt signalling.

Iguratimod ameliorates rheumatoid arthritis progression through regulating miR-146a mediated IRAK1 expression and TRAF6/JNK1 pathway: an in vivo and in vitro study.

OBJECTIVES: This study aimed to evaluate the therapeutic effect of iguratimod and its regulatory role on microRNA (miR-146a) and the downstream genes in treating rheumatoid arthritis-fibroblast-like synoviocytes (RA-FLS) and collagen-induced arthritis (CIA) rat model. METHODS: RA-FLS was isolated from knee synovial tissue of an active RA patient. In vitro, the effect of miR-146a mimic/inhibition on RA-FLS functions was investigated. Then the effect of Iguratimod on cell viability, proliferation, apoptosis, migration, invasion, inflammatory cytokines, miR-146a and its downstream gene/pathway in RA-FLS was evaluated. In vivo, the collagen induced arthritis (CIA) rat model was constructed, then the effects of iguratimod, miR-146a inhibition and their combination on treating CIA rat were assessed. RESULTS: Iguratimod treatment increased miR-146a while decreased cell proliferation, IRAK1 and TRAF6/JNK1 pathway in RA-FLS in a dose-dependent manner. Notably, iguratimod treatment repressed cell proliferation, migration, invasion, TNF-α, IL-1ß, IL-6, IL-17, IRAK1 and TRAF6/JNK1 pathway in RA-FLS, while miR-146a inhibition alleviated the abovementioned effects of Iguratimod on RA-FLS. The in vivo experiments disclosed that iguratimod reduced systemic arthritis score, and decreased TNF-α, IL-1ß, IL-6, IL-17, IRAK1 as well as TRAF6/JNK1 pathway, while enhanced apoptosis in synovial tissue of CIA rat model; and in miR-146a inhibition treated CIA rat model, the effect of iguratimod was diminished. CONCLUSIONS: Iguratimod ameliorates RA progression via regulating miR-146a mediated IRAK1 expression and TRAF6/JNK1 pathway.

JNK1 regulates RANKL-induced osteoclastogenesis via activation of a novel Bcl-2-Beclin1-autophagy pathway.

JNK1 plays an important role in osteoclastogenesis in response to the osteoclastogenic cytokine receptor activator for nuclear factor-κB ligand (RANKL). JNK1 is widely accepted as an autophagy regulator under stress conditions. However, the role of JNK1-mediated autophagy in osteoclastogenesis remains largely unknown. In the current study, our data showed that JNK1 inhibition by a pharmacological inhibitor or RNA interference significantly reduced the autophagic response induced by RANKL in osteoclast precursors (OCPs) derived from bone marrow-derived macrophages. Overexpression of the key autophagy protein Beclin1 rescued autophagy deficiency and osteoclastogenesis in the presence of a JNK inhibitor (SP600125). In contrast, JNK activator (anisomycin)-induced autophagy was blocked by Beclin1 knockdown in OCPs. In addition, JNK1 inhibition increased apoptosis and blocked autophagy, whereas overexpression of Beclin1 reversed the enhanced apoptosis induced by JNK1 inhibition in OCPs. Furthermore, RANKL could induce the phosphorylation of Bcl-2, subsequently dissociating Beclin1 from the Bcl-2-Beclin1 complex, which could be blocked by JNK1 inhibition. Collectively, this study revealed that JNK1 regulated osteoclastogenesis by activating Bcl-2-Beclin1-autophagy signaling in addition to the classic c-Jun/activator protein 1 pathway, which provided the first evidence for the contribution of JNK1 signaling to OCP autophagy and the autophagic mechanism underlying JNK1-regulated osteoclastogenesis. An important osteoclastogenesis-regulating signaling pathway (JNK1-Bcl-2-Beclin1-autophagy activation) was identified, which provides novel potential targets for the clinical therapy of metabolic bone diseases.-Ke, D., Ji, L., Wang, Y., Fu, X., Chen, J., Wang, F., Zhao, D., Xue, Y., Lan, X., Hou, J. JNK1 regulates RANKL-induced osteoclastogenesis via activation of a novel Bcl-2-Beclin1-autophagy pathway.

Correction to: MiRNA-126 expression inhibits IL-23R mediated TNF-α or IFN-γ production in fibroblast-like synoviocytes in a mice model of collagen-induced rheumatoid arthritis.

The authors would like to add an article note stating that "The authors Jie Gao and Ruina Kong have equally contributed to the article".

Autophagy exerts pivotal roles in regulatory effects of 1α,25-(OH)2D3 on the osteoclastogenesis.

As an active form of vitamin D3, 1α,25-(OH)2D3 has a positive therapeutical effect on osteoporosis. However, 1α,25-(OH)2D3 can not only promote the osteoclastogenesis, but also inhibit the proliferation of osteoclast precursors (OCPs). Autophagy is regulated by 1α,25-(OH)2D3 and is considered to promote the osteoclastogenesis. Nevertheless, the role of 1α,25-(OH)2D3 in OCPs' autophagy remains unknown. Our study aims to explore whether the effect of 1α,25-(OH)2D3 on osteoclastogenesis is related to its regulation in autophagy. The results showed that 1α,25-(OH)2D3 exhibited a direct inhibitory effect on the autophagy activity and the proliferation of OCPs derived from bone marrow-derived macrophages (BMMs), which was reversed by the overexpression of autophagy-related gene. In presence of RANKL, the autophagy capacity of OCPs and the differentiation from OCPs into mature osteoclasts were significantly enhanced by 1α,25-(OH)2D3, while the suppression of autophagy with spautin-1 or 3-MA downregulated the osteoclastogenesis capacity. In summary, 1α,25-(OH)2D3 can directly suppress OCPs autophagy, which negatively regulates the proliferation of OCPs without RANKL. 1α,25-(OH)2D3 can indirectly upregulate the autophagy response of OCPs, thereby enhancing the osteoclasts formation in presence of RANKL. Therefore, our study found that 1α,25-(OH)2D3 had a dual effect on osteoclastogenesis by regulating autophagy, suggesting that some drugs targeting autophagy may act as an effective supplement of 1α,25-(OH)2D3 in treating osteoporosis.

MiRNA-126 expression inhibits IL-23R mediated TNF-α or IFN-γ production in fibroblast-like synoviocytes in a mice model of collagen-induced rheumatoid arthritis.

Both miR-126 and IL-23R affect rheumatoid arthritis (RA) procession. This study aimed to investigate the association of miR-126 and IL-23R and the possible modulation of miR-126 to RA pathogenesis. Serum, synovial tissue and synovial fluid were collected from patients with RA, and expression of miR-126, IL-23R, TNF-α and IFN-γ were detected. Fibroblast-like synoviocytes (FLS) was established using a collagen-induced arthritis mice model. The expression of miR-126 was manual intervened using pro-miR-126 and anti-miR-126 encoding lentivirus plasmids, or miR-126 agonists and corresponding negative controls. MiR-126 expression was inhibited in RA patients when compared with controls (P < 0.05). TNF-α and IFN-γ production and IL-23R expression were significantly upregulated in RA patients when compared to controls (P < 0.05). In pro-miR-126 treated FLS cells, the administration of pro-miR-126 plasmids upregulated miR-126, but inhibited IL-23R, TNF-α and IFN-γ expression or production. Moreover, the miR-126 agonist reversed the effects of the anti-miR-126 plasmid on FLS. These results revealed that miR-126 negative regulated the expression of IL-23R, TNF-α and IFN-γ. These results suggest the key impact of miR-126 on RA procession. Moreover, pro-miR-126 might be explored to be a potential therapy for RA.

microRNA-126 targeting PIK3R2 promotes rheumatoid arthritis synovial fibro-blasts proliferation and resistance to apoptosis by regulating PI3K/AKT pathway.

OBJECTIVE: The purpose of our study was to elucidate the impact of microRNA-126 (miR-126) targeting PIK3R2 gene on cell proliferation and apoptosis of rheumatoid arthritis synovial fibro-blasts (RASFs) by regulating PI3K/AKT signal pathway. METHODS: The synovial tissue samples of this study were from 55 RA patients undergoing joint replacement and 27 healthy people undergoing joint repair due to trauma. The target genes of miR-126 were collected by the TargetScan and PIK3R2 as the direct target gene of miR-126 was confirmed by dual-luciferase reporter assay system. Our experiment had five groups including the blank control, miR-126 mimic, miR-126 mimic control, miR-126 inhibitor and miR-126 inhibitor control groups. Additionally, real-time quantitative polymerase chain reaction (RT-qPCR), Western-Blot, cell counting kit (CCK-8) and flow cytometry were carried out in this study. RESULTS: Compared with healthy individuals, the RA patients had increased miR-126, but decreased PIK3R2 mRNA expressions in the synovial tissues. Pearson correlation analysis indicated that miR-126 expression was negatively correlated with PIK3R2 mRNA expression (all P<0.05). When compared with the blank group respectively, the miR-126 mimic group had raising cell proportions in S and G2/M phases with reduced rate of cell apoptosis, while the miR-126 inhibitor group had raising cell proportions in G0/G1 and G2/M phases with increased rate of cell apoptosis (all P<0.05). Besides, compared with the blank control group, the miR-126 mimic group had declined expression of PIK3R2 protein with ascended expression of PI3K and p-AKT (all P<0.05), while the miR-126 inhibitor group had increased expression of PIK3R2 protein with decreased expression of PI3K and p-AKT (all P<0.05). CONCLUSION: Our study demonstrated that down-regulation of miR-126 may indirectly inhibit PI3K/AKT signaling pathway to disrupt the imbalance between growth and death of RASFs by targeting PIK3R2, which may be clinically helpful to find therapeutic strategies directed toward miR-126 function for RA patients.

Exosomes from osteoarthritic fibroblast-like synoviocytes promote cartilage ferroptosis and damage via delivering microRNA-19b-3p to target SLC7A11 in osteoarthritis.

Objective: Our previous studies revealed that normal synovial exosomes promoted chondrogenesis, and microRNA (miR)-19b-3p independently related to osteoarthritis (OA) risk. Subsequently, this study intended to further explore the effect of OA fibroblast-like synoviocyte (OA-FLS) exosomal miR-19b-3p on OA ferroptosis and its potential mechanisms. Methods: Interleukin (IL)-1ß-stimulated chondrocytes and medial meniscus surgery were used to construct the OA cellular model and the OA rat model, respectively. OA-FLS exosomes with/without miR-19b-3p modification were added to the IL-1ß-stimulated chondrocytes and OA rat models, followed by direct miR-19b-3p mimic/inhibitor transfection with/without SLC7A11 overexpression plasmids. miR-19b-3p, ferroptosis-related markers (malondialdehyde (MDA), glutathione (GSH)/oxidized glutathione (GSSG), ferrous ion (Fe2+), glutathione peroxidase 4 (GPX4), solute carrier family 7 member 11 (SLC7A11), and acyl-CoA synthetase long-chain family member 4 (ACSL4)), mitochondrial membrane potential (MMP), and reactive oxygen species (ROS) levels were detected. Results: Enhanced ferroptosis reflected by dysregulated ferroptosis-related markers, a reduced MMP, and an increased ROS was observed in cartilage tissues from OA patients vs. controls, IL-1ß-stimulated chondrocytes vs. normal ones, and OA rat models vs. sham, so did miR-19b-3p. OA-FLS exosomes promoted MDA, Fe2+, ACSL4, and ROS but reduced cell viability, GSH/GSSG, GPX4, SLC7A11, and MMP in IL-1ß-stimulated chondrocytes, whose effect was enhanced by miR-19b-3p mimics and attenuated by miR-19b-3p inhibitors. miR-19b-3p negatively regulated SLC7A11 and directly bound to SLC7A11 via luciferase reporter gene assay. Furthermore, SLC7A11 overexpression weakened miR-19b-3p mimics' effect on ferroptosis-related markers, MMP, or ROS in IL-1ß-stimulated chondrocytes. OA-FLS exosomes also induced cartilage damage and ferroptosis in OA rats whose influence was tempered by miR-19b-3p inhibitors. Conclusion: OA-FLS exosomal miR-19b-3p enhances cartilage ferroptosis and damage by sponging SLC7A11 in OA, indicating a potential linkage among synovium, cartilage, and ferroptosis during the OA process.

Synovial mesenchymal stem cell-derived exosomal miR-320c enhances chondrogenesis by targeting ADAM19.

Background: Synovial mesenchymal stem cell (SMSC)-derived exosomes show treatment potential in osteoarthritis, although their functional mechanism is still unclear. Materials & methods: Osteoarthritis chondrocytes and normal SMSC were cultured. Subsequently, chondrocytes were co-cultured with SMSC or miR-320c-overexpressing SMSC-derived exosomes, or directly transfected with miR-320c mimic. Furthermore, compensate experiments were conducted. Results: SMSC promoted chondrocyte proliferation, migration, COL2A1 and ACAN expressions while suppressing apoptosis by transmitting exosomes. Furthermore, miR-320c-overexpressing SMSC-derived exosomes and direct miR-320c overexpression in chondrocytes presented more significant effect on enhancing chondrogenesis. In addition, miR-320c directly targeted ADAM19, and ADAM19 overexpression compensated the regulation of miR-320c on chondrogenesis. Conclusion: SMSC-derived exosomal miR-320c enhances chondrogenesis through targeting ADAM19, highlighting a potentially novel mechanism of SMSC in treating osteoarthritis.

MicroRNA-126 promotes proliferation, migration, invasion and endothelial differentiation while inhibits apoptosis and osteogenic differentiation of bone marrow-derived mesenchymal stem cells.

Bone marrow-derived mesenchymal stem cells (BMSCs) are widely used for the treatment of inflammatory and immune diseases, and microRNA-126 (miR-126) is a critical regulator in inflammation as well as immunity. However, the mediating role of miR-126 in BMSCs is still not clear. Thus, this study aimed to preliminarily investigate the effect of miR-126 on proliferation, apoptosis, migration, invasion, differentiation, and its potential regulating pathways in BMSCs. Human BMSCs were obtained and infected with miR-126 overexpression lentivirus, control overexpression lentivirus, miR-126 knock-down lentivirus and control knock-down lentivirus, then cell functions, the PI3 K/AKT pathway and MEK1/ERK1 pathway were evaluated. Subsequently, PI3 K overexpression plasmid and MEK1 overexpression plasmid were transfected into BMSCs with miR-126 knockdown, then the cell functions were assessed as well. BMSCs with miR-126 overexpression displayed elevated proliferation, migration and invasion while decreased apoptosis; however, BMSCs with miR-126 knockdown presented with decreased proliferation, migration, invasion but increased apoptosis. As for differentiation, BMSCs with miR-126 overexpression showed higher levels of CD31, eNOS and VE-cadherin but lower expressions of ALP, OPN and RUNX2, while BMSCs with miR-126 knockdown disclosed the opposite results. Additionally, BMSCs with miR-126 overexpression showed elevated PI3 K, pAKT, MEK1 and pERK1 expressions, while BMSCs with miR-126 knockdown displayed opposite results. Furthermore, PI3 K overexpression and MEK1 overexpression both reversed the effects of miR-126 on cell functions in BMSCs. In conclusion, miR-126 is a genetic regulator in BMSCs via modulating multiple cell functions through the PI3 K/AKT and MEK1/ERK1 signaling pathways.

Interleukin-37 contributes to the pathogenesis of gout by affecting PDZ domain-containing 1 protein through the nuclear factor-kappa B pathway.

OBJECTIVE: Our objective was to explore the molecular pathogenesis of the onset of gout and the mechanism underlying the effect of interleukin (IL)-37 on PDZ domain-containing 1 (PDZK1) protein through the nuclear factor-κB signaling pathway. METHODS: Real-time PCR and western blotting were used to detect expression of PDZK1 mRNA and protein, respectively, in the HK-2 cell line. The inhibitors pyrrolidine dithiocarbamate (PDTC) and wortmannin were added to HK-2 cells stimulated by IL-37, and changes in PDZK1 protein were detected by western blotting. RESULTS: Based on our previous research, we used 10 µmol/L PDTC. We detected no significant change in PDZK1 at the mRNA level among the IL-37, PDTC+IL-37, and wortmannin+IL-37 groups. With increasing IL-37 concentration, the protein level of PDZK1 increased. After adding wortmannin, the protein level of PDZK1 increased with increasing concentration of IL-37, albeit not significantly, and the level of PDZK1 remained lower than that with IL-37 alone. After adding PDTC, the protein level of PDZK1 showed a trend to decrease with increasing concentrations of IL-37 up to 40 ng/mL. The immunofluorescence results supported the western blot results. CONCLUSIONS: IL-37 can affect protein expression of PDZK1, but not at the translational level, in the pathogenesis of gout.

Indirect comparison of teriparatide, denosumab, and oral bisphosphonates for the prevention of vertebral and nonvertebral fractures in postmenopausal women with osteoporosis.

OBJECTIVE: This study aims to compare the efficacy of teriparatide, denosumab, and oral bisphosphonates for reducing fracture risk in postmenopausal women with osteoporosis. METHODS: We searched the literature, via PubMed, Medline, Embase, and the Cochrane Library, to screen citations from January 1996 to October 2014 for inclusion in this study. A mixed-treatment comparison meta-analysis within a Bayesian framework was performed by WinBUGS version 1.4.3 software. The proportions of women with vertebral fractures and women with nonvertebral fractures were analyzed. RESULTS: Our meta-analysis results indicated that all of the therapies-except etidronate-achieved a statistically significant reduction of fractures compared with placebo. Teriparatide and denosumab were more effective than alendronate and risedronate for reducing vertebral fracture (teriparatide vs alendronate: odds ratio [OR], 1.76; 95% CI, 1.03-2.98; teriparatide vs risedronate: OR, 1.92; 95% CI, 1.13-3.19; denosumab vs alendronate: OR, 1.67; 95% CI, 1.06-2.67; denosumab vs risedronate: OR, 1.84; 95% CI, 1.16-2.92). Teriparatide, denosumab, alendronate, and risedronate also reduced the risk of nonvertebral fracture compared with placebo. Results of subgroup analysis showed that denosumab (OR, 0.6; 95% CI, 0.37-0.98), alendronate (OR, 0.61; 95% CI, 0.39-0.96), and risedronate (OR, 0.63; 95% CI, 0.46-0.86) can reduce the risk of hip fracture and that risedronate (OR, 0.59; 95% CI, 0.4-0.88) can also reduce the risk of upper-arm fracture. CONCLUSIONS: Teriparatide, denosumab, alendronate, and risedronate are effective in reducing the risk of vertebral and nonvertebral fractures in postmenopausal women with osteoporosis. Furthermore, denosumab, alendronate, and risedronate can reduce the risk of hip fracture, and risedronate can also reduce the risk of upper-arm fracture.