Expression of miR-206 in Human Knee Articular Chondrocytes and Effects of miR-206 on Proliferation and Apoptosis of Articular Chondrocytes

Comprehensive analysis of microRNA expression in lumbar facet joint capsules and synovium of patients with osteoarthritis: Comparison between early-stage and late-stage osteoarthritis samples from a single individual

BACKGROUND

MicroRNA is attracting attention as a therapeutic target for osteoarthritis. We focused on joint capsules and synovium in lumbar facet joint osteoarthritis. The purpose of this study was to identify microRNAs that are upregulated in lumbar facet joint capsules and synovium with osteoarthritis.

METHODS

We included patients who underwent spinal fusion for degenerative lumbar spine diseases. We selected patients who had both early-stage and late-stage facet joint osteoarthritis in a single individual. We extracted joint capsule and synovium samples from these patients and isolated microRNAs. During the screening phase, we compared early-stage and late-stage osteoarthritis samples from the same individual. We identified microRNAs with >2-fold change in expression in 75% or more of patients with late-stage osteoarthritis using next generation sequencing. During the technical validation phase, the same samples were used for real-time polymerase chain reaction. We identified microRNAs with >2-fold change in expression in 62.5% or more of patients with late-stage osteoarthritis.

RESULTS

Of 40 patients who underwent spinal fusion, we selected eight patients with both early-stage and late-stage facet joint osteoarthritis. During the screening phase, we identified eight upregulated microRNAs out of 2274 microRNAs in late-stage OA. In late-stage OA, two microRNAs (miR-133a-5p and miR-144-3p) were upregulated in seven patients and six microRNAs (miR-133a-3p, miR-133b, miR-206, miR-20a-5p, miR-301a-3p, and miR-32-5p) were upregulated in six patients. During the technical validation phase, we found significant upregulation of miR-144-3p expression in late-stage osteoarthritis compared with early-stage osteoarthritis. Expression of the other microRNAs was not significantly different according to the paired-t test. However, miR-133a-3p, miR-133b, and miR-206 were upregulated >2-fold in 62.5% or more of patients with late-stage osteoarthritis.

CONCLUSIONS

Some of the microRNAs identified in this study might be involved in joint capsule degeneration or synovitis.

Selenomethionine Antagonized microRNAs Involved in Apoptosis of Rat Articular Cartilage Induced by T-2 Toxin

T-2 toxin and selenium deficiency are considered important etiologies of Kashin-Beck disease (KBD), although the exact mechanism is still unclear. To identify differentially expressed microRNAs (DE-miRNAs) in the articular cartilage of rats exposed to T-2 toxin and selenomethionine (SeMet) supplementation, thirty-six 4-week-old Sprague Dawley rats were divided into a control group (gavaged with 4% anhydrous ethanol), a T-2 group (gavaged with 100 ng/g·bw/day T-2 toxin), and a T-2 + SeMet group (gavaged with 100 ng/g·bw/day T-2 toxin and 0.5 mg/kg·bw/day SeMet), respectively. Toluidine blue staining was performed to detect the pathological changes of articular cartilage. Three rats per group were randomly selected for high-throughput sequencing of articular cartilage. Target genes of DE-miRNAs were predicted using miRanda and RNAhybrid databases, and the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway were enriched. The network map of miRNA-target genes was constructed using Cytoscape software. The expression profiles of miRNAs associated with KBD were obtained from the Gene Expression Omnibus database. Additionally, the DE-miRNAs were selected for real-time quantitative PCR (RT-qPCR) verification. Toluidine blue staining demonstrated that T-2 toxin damaged articular cartilage and SeMet effectively alleviated articular cartilage lesions. A total of 50 DE-miRNAs (28 upregulated and 22 downregulated) in the T-2 group vs. the control group, 18 DE-miRNAs (6 upregulated and 12 downregulated) in the T-2 + SeMet group vs. the control group, and 25 DE-miRNAs (5 upregulated and 20 downregulated) in the T-2 + SeMet group vs. the T-2 group were identified. Enrichment analysis showed the target genes of DE-miRNAs were associated with apoptosis, and in the MAPK and TGF-β signaling pathways in the T-2 group vs. the control group. However, the pathway of apoptosis was not significant in the T-2 + SeMet group vs. the control group. These results indicated that T-2 toxin induced apoptosis, whereas SeMet supplementation antagonized apoptosis. Apoptosis and autophagy occurred simultaneously in the T-2 + SeMet group vs. T-2 group, and autophagy may inhibit apoptosis to protect cartilage. Compared with the GSE186593 dataset, the evidence of miR-133a-3p involved in apoptosis was more abundant. The results of RT-qPCR validation were consistent with RNA sequencing results. Our findings suggested that apoptosis was involved in articular cartilage lesions induced by T-2 toxin, whereas SeMet supplementation antagonized apoptosis, and that miR-133a-3p most probably played a central role in the apoptosis process.

Comprehensive analysis of differently expression mRNA and non-coding RNAs, and their regulatory mechanisms on relationship in thiram-induced tibial dyschondroplasia in chicken

Thiram pollution is one of the main causes of tibial dyschondroplasia (TD) induced by feed sources. Several studies have speculated that miRNA, circRNA and lncRNA may have significant impact on the development of TD, however, the specific mRNAs and noncoding RNAs and their respective regulatory mechanisms and functions in the development of TD have not been explored. Therefore, in this present study, we screened the differentially expressed mRNA, miRNA, circRNA and lncRNA by whole-transcriptome sequencing (RNA-seq) and differentially expressed genes (DEGs) enrichment, as well as constructed the interaction network among the mRNA-miRNA, mRNA-lncRNA and mRNA-miRNA-circRNA. The sequencing results were verified by fluorescence real-time quantitative PCR (RT-qPCR). The results obtained in this study, revealed that the cells were atrophied and disordered in the TD group, and the expression of BMP6, TGF-β and VEGF were significantly reduced. A total of 141 mRNAs, 10 miRNAs, 23 lncRNAs and 35 circRNAs of DEGs were obtained (p<0.05) Theses DEGs were enriched in the adhere junction and insulin signaling pathways. In addition, the mRNA-miRNA-circRNA network suggested that several pivotal ceRNA showed a regulatory relationship between the transcripts with miRNA, circRNA or lncRNA. Taken together, the results in the present study, represent an insight for further functional research on the ceRNA regulatory mechanism of TD in broilers.

Crosstalk Among circRNA/lncRNA, miRNA, and mRNA in Osteoarthritis

Osteoarthritis (OA) is a joint disease that is pervasive in life, and the incidence and mortality of OA are increasing, causing many adverse effects on people's life. Therefore, it is very vital to identify new biomarkers and therapeutic targets in the clinical diagnosis and treatment of OA. ncRNA is a nonprotein-coding RNA that does not translate into proteins but participates in protein translation. At the RNA level, it can perform biological functions. Many studies have found that miRNA, lncRNA, and circRNA are closely related to the course of OA and play important regulatory roles in transcription, post-transcription, and post-translation, which can be used as biological targets for the prevention, diagnosis, and treatment of OA. In this review, we summarized and described the various roles of different types of miRNA, lncRNA, and circRNA in OA, the roles of different lncRNA/circRNA-miRNA-mRNA axis in OA, and the possible prospects of these ncRNAs in clinical application.

miRNAs Related to Different Processes of Fracture Healing: An Integrative Overview

Fracture healing is a complex, dynamic process that is directed by cellular communication and requires multiple cell types, such as osteoblasts, osteoclasts, and immune cells. Physiological fracture healing can be divided into several phases that consist of different processes, such as angiogenesis, osteogenesis, and bone resorption/remodelling. This is needed to guarantee proper bone regeneration after fracture. Communication and molecular regulation between different cell types and within cells is therefore key in successfully orchestrating these processes to ensure adequate bone healing. Among others, microRNAs (miRNAs) play an important role in cellular communication. microRNAs are small, non-coding RNA molecules of ~22 nucleotides long that can greatly influence gene expression by post-transcriptional regulation. Over the course of the past decade, more insights have been gained in the field of miRNAs and their role in cellular signalling in both inter- and intracellular pathways. The interplay between miRNAs and their mRNA targets, and the effect thereof on different processes and aspects within fracture healing, have shown to be interesting research topics with possible future diagnostic and therapeutic potential. Considering bone regeneration, research moreover focusses on specific microRNAs and their involvement in individual pathways. However, it is required to combine these data to gain more understanding on the effects of miRNAs in the dynamic process of fracture healing, and to enhance their translational application in research, as well as in the clinic. Therefore, this review aims to provide an integrative overview on miRNAs in fracture healing, related to several key aspects in the fracture healing cascade. A special focus will be put on hypoxia, angiogenesis, bone resorption, osteoclastogenesis, mineralization, osteogenesis, osteoblastogenesis, osteocytogenesis, and chondrogenesis.

MiR-206 regulates the Th17/Treg ratio during osteoarthritis

BACKGROUND

The present study aimed to determine the functional role of miR-206 in T helper 17 (Th17)/regulatory T (Treg) cell differentiation during the development of osteoarthritis (OA).

METHODS

Patients with OA and healthy controls were recruited for investigating the association between miR-206 and Th17/Treg ratio. Transfection experiments were conducted in CD4⁺ T cells to verify the mechanism of miR-206 on the balance of Treg/Th17. OA model was constructed to detect the clinical score, histopathological changes and Treg/Th17 ratio. OA model was induced in rats to verify the effect of miR-206 inhibition on Th17/Treg immunoregulation.

RESULTS

High expression of miR-206 was positively correlated with peripheral Th17/Treg imbalance in patients with OA. The interactions between miR-206 and the 3' untranslated regions (3'-UTR) of suppressor of cytokine signaling-3 (SOCS3) and fork head transcriptional factor 3 (Foxp3) were confirmed by luciferase reporter assays. MiR-206 disturbed the Th17/Treg balance by targeting SOCS3 and Foxp3. In vivo assay demonstrated that antagomiR directed against miR-206 restored Th17/Treg balance during the development of OA.

CONCLUSION

MiR-206 contributed to the progression of OA by modulating Th17/Treg imbalance, suggesting that miR-206 inhibition might be a promising therapeutic strategy for the treatment of OA.

Combining bulk and single-cell RNA-sequencing data to reveal gene expression pattern of chondrocytes in the osteoarthritic knee

Osteoarthritis (OA) occurs mostly in the knees, hips, finger interphalangeal joints, and spinal facet joints, and is characterized by cartilage degeneration. The existing bulk RNA sequencing (bulk RNA-seq) and single-cell sequencing (scRNA-seq) data for chondrocytes in the osteoarthritic knee joint provide the expression profiles of entire cell populations and individual cells, respectively. Here, we aimed to analyze these two types of sequencing data in order to obtain a more comprehensive understanding of OA. We compared the analysis results of bulk RNA-seq and scRNA-seq from the dataset GSE114007 and the dataset GSE104782, respectively, and identified the differentially expressed genes (DEGs). Then, we tried to find the key The transcription factor is a more fomal term (TFs) and long non-coding RNA (lncRNA) regulation. We highlighted 271 genes that were simultaneously suggested by these two types of data and provided their possible expression pattern in OA. Among the 271 genes, we identified 14 TFs, and TWIST2, MYBL2, RELA, JUN, KLF4, and PTTG1 could be the key TFs for the 271 genes. We also found that 8 lncRNAs among the 271 genes and the lncRNA regulation between CYTOR and NRP1 could contribute to the pain and vascularization of cartilage in the osteoarthritic knee. In short, our research combined the analysis results of bulk RNA-seq and scRNA-seq data for OA chondrocytes, which will contribute to further elucidation of the molecular mechanisms of OA pathogenesis.

The protective role of MiR-206 in regulating cardiomyocytes apoptosis induced by ischemic injury by targeting PTP1B

MicroRNAs play essential roles in the regulation and pathophysiology of acute myocardial infarction (AMI). The purpose of the present study was to assess the expression signature of miR-206 in rat heart with AMI and the corresponding molecular mechanism. The expression of miR-206 significantly decreased in the infarcted myocardial areas and in hypoxia-induced cardiomyocytes, compared with that in the noninfarcted areas. Overexpression of miR-206 decreased cardiomyocytes apoptosis and the down-regulation of miR-206 increased cardiomyocytes apoptosis in vitro. In addition, overexpression of miR-206 in rat heart in vivo remarkably reduced myocardial infarct size and cardiomyocytes apoptosis. We identified that miR-206 had a protective effect on cardiomyocytes apoptosis with the association of its target protein tyrosine phosphatase 1B (PTP1B). Gain-of-function of miR-206 inhibited PTP1B expression and loss-of-function of miR-206 up-regulated PTP1B expression. Furthermore, overexpression of PTP1B significantly increased cardiomyocytes apoptosis. These results together suggest the protective effect of miR-206 against cardiomyocytes apoptosis induced by AMI by targeting PTP1B.

A microRNA Signature for Impaired Wound-Healing and Ectopic Bone Formation in Humans

BACKGROUND

Heterotopic ossification (HO) is characterized by the abnormal growth of ectopic bone in soft tissues, frequently occurring within the military population because of extensive orthopaedic combat trauma. MicroRNAs (miRNAs) are small noncoding RNAs that act as post-transcriptional regulators of gene expression. We hypothesized that a clinically relevant miRNA signature could be detected in patients following injury that progressed to form HO (HO+) or did not form HO (HO-).

METHODS

Tissue samples were obtained from injured servicemembers during their initial surgical debridements, and miRNA profiling was performed using a real-time miRNA polymerase chain reaction (PCR) array. Primary mesenchymal progenitor cells (MPCs) were harvested from debrided traumatized human muscle tissue, and cells were isolated and cultured in vitro. Mimic miRNAs were transfected into MPCs, followed by downstream in vitro analyses.

RESULTS

The investigation of the miRNA expression profile in the tissue of HO+ compared with HO- patients demonstrated a molecular signature that included the upregulation of miR-1, miR-133a, miR-133b, miR-206, miR-26a, and miR-125b. Transfection of each of these mature miRNAs into MPCs followed by osteogenic induction demonstrated that miR-1, miR-133a, miR-133b, and miR-206 enhanced osteogenic differentiation compared with control treatments. In silico and in vitro analyses identified the transcription factor SOX9 as a candidate downstream target of miR-1 and miR-206 miRNAs.

CONCLUSIONS

Our data demonstrated a molecular signature of miRNAs in the soft tissue of wounded servicemembers that was associated with the development of HO, providing novel insights into the underlying molecular mechanisms associated with posttraumatic HO.

LEVEL OF EVIDENCE

Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Interplay between C-type lectin receptors and microRNAs in cellular homeostasis and immune response

C-type lectin receptors (CLRs) belong to the family of pattern recognition receptors (PRRs). They have a critical role to play in the regulation of a range of physiological functions including development, respiration, angiogenesis, inflammation, and immunity. CLRs can recognize distinct and conserved exogenous pathogen-associated as well as endogenous damage-associated molecular patterns. These interactions set off downstream signaling cascades, leading to the production of inflammatory mediators, activation of effector immune cells as well as regulation of the developmental and physiological homeostasis. CLR signaling must be tightly controlled to circumvent the excessive inflammatory burden and to maintain the cellular homeostasis. Recently, MicroRNAs (miRNAs) have been shown to be important regulators of expression of CLRs and their downstream signaling. The delicate balance between miRNAs and CLRs seems crucial in almost all aspects of multicellular life. Any dysregulations in the miRNA-CLR axes may lead to tumorigenesis or inflammatory diseases. Here, we present an overview of the current understanding of the central role of miRNAs in the regulation of CLR expression, profoundly impacting upon homeostasis and immunity, and thus, development of therapeutics against immune disorders.

MiR-206 suppresses proliferation and epithelial-mesenchymal transition of renal cell carcinoma by inhibiting CDK6 expression

Increasing evidence indicates that miRNAs are involved in tumorigenesis of human renal cell carcinoma (RCC). However, the role of miR-206 is still unknown. This study aimed to investigate the possible mechanism of miR-206 in progression of RCC. Here, compared with adjacent normal renal tissues and HK-2 cells, miR-206 level was markedly decreased, whereas CDK6 level was obviously increased in RCC tissues and cell lines. MiR-206 was inversely associated with lymph node metastasis and TNM stage, and acted as an independent prognostic factor in RCC. MiR-206 effectively caused apoptosis and cell cycle arrest at G0/G1 phase, and affected the growth of xenograft tumor of nude mice. MiR-206 also inhibited migration and invasion of RCC cells by modulating the expressions of EMT-related genes. Dual-luciferase assay demonstrated CDK6 was a direct target of miR-206. CDK6 silencing aggravated the inhibition effects of miR-206. In conclusion, miR-206 suppresses proliferation and EMT of RCC by inhibiting CDK6 expression. The miR-206/CDK6 axis may provide a novel insight into tumorigenesis of RCC.

Noncoding RNAs: New regulatory code in chondrocyte apoptosis and autophagy

Osteoarthritis (OA) is a bone and joint disease characterized by progressive cartilage degradation. In the face of global trends of population aging, OA is expected to become the fourth most common disabling disease by 2020. Nevertheless, the detailed pathogenesis of OA has not yet been elucidated. Noncoding RNAs (ncRNAs), including long noncoding RNAs, microRNAs, and circular RNAs, do not encode proteins but have recently emerged as important regulators of apoptosis and autophagy of chondrocytes, thereby highlighting a potential role in chondrocyte injury leading to OA onset and progression. We here review recent findings on these regulatory roles of ncRNAs to provide new directions for research on the pathogenesis of OA and offer new therapeutic targets for prevention and treatment. This article is categorized under: RNA in Disease and Development > RNA in Disease RNA in Disease and Development > RNA in Development.

MicroRNA-29b regulates hypertrophy of murine mesenchymal stem cells induced toward chondrogenesis

OBJECTIVE

Chondrocyte hypertrophy, a terminal stage of chondrocyte differentiation, is essential to the endochondral bone formation and is one of the major pathological factors in osteoarthritis. This study investigated the role of microRNA-29b (miR-29b), which is involved in chondrogenesis, in the regulation of hypertrophy in chondrocytes.

METHODS

miR-29b expression was assessed during murine mesenchymal stem cells (mMSCs) chondrogenesis. To detect whether miR-29b affects chondrocyte hypertrophy, the mMSCs induced toward chondrogenesis were transfected with miR-29b or its antisense inhibitor (antagomiR-29b). Finally, the differential effects of antagomiR-29b on chondrocytes at different differentiation stages were evaluated by loss-of-function experiments.

RESULTS

miR-29b expression was low-level during the early chondrogenic differentiation, however, it was changed to high level during hypertrophy. Subsequently, the gain-of-function and loss-of-function experiments had confirmed that miR-29b promoted hypertrophy in mMSC-derived chondrocytes. In addition, we confirmed that on day 7, when cells were treated with antagomiR-29b, was the optimal intervention time for preventing hypertrophic phenotype of mMSCs in vitro.

CONCLUSION

miR-29b regulated chondrogenesis homeostasis and enhance hypertrophic phenotype. These data suggest that miR-29b is a key regulator of the chondrocyte phenotype derived from mMSCs and it might be a potential target for articular cartilage repair.

Spatio-Temporal Expression and Functional Analysis of miR-206 in Developing Orofacial Tissue

BACKGROUND

Development of the mammalian palate is dependent on precise, spatiotemporal expression of a panoply of genes. MicroRNAs (miRNAs), the largest family of noncoding RNAs, function as crucial modulators of cell and tissue differentiation, regulating expression of key downstream genes.

OBSERVATIONS

Our laboratory has previously identified several developmentally regulated miRNAs, including miR-206, during critical stages of palatal morphogenesis. The current study reports spatiotemporal distribution of miR-206 during development of the murine secondary palate (gestational days 12.5-14.5).

RESULT AND CONCLUSION

Potential cellular functions and downstream gene targets of miR-206 were investigated using functional assays and expression profiling, respectively. Functional analyses highlighted potential roles of miR-206 in governing TGFß- and Wnt signaling in mesenchymal cells of the developing secondary palate. In addition, altered expression of miR-206 within developing palatal tissue of TGFß3-/- fetuses reinforced the premise that crosstalk between this miRNA and TGFß3 is crucial for secondary palate development.

RNA sequencing data integration reveals an miRNA interactome of osteoarthritis cartilage

Objective

To uncover the microRNA (miRNA) interactome of the osteoarthritis (OA) pathophysiological process in the cartilage.

Methods

We performed RNA sequencing in 130 samples (n=35 and n=30 pairs for messenger RNA (mRNA) and miRNA, respectively) on macroscopically preserved and lesioned OA cartilage from the same patient and performed differential expression (DE) analysis of miRNA and mRNAs. To build an OA-specific miRNA interactome, a prioritisation scheme was applied based on inverse Pearson’s correlations and inverse DE of miRNAs and mRNAs. Subsequently, these were filtered by those present in predicted (TargetScan/microT-CDS) and/or experimentally validated (miRTarBase/TarBase) public databases. Pathway enrichment analysis was applied to elucidate OA-related pathways likely mediated by miRNA regulatory mechanisms.

Results

We found 142 miRNAs and 2387 mRNAs to be differentially expressed between lesioned and preserved OA articular cartilage. After applying prioritisation towards likely miRNA-mRNA targets, a regulatory network of 62 miRNAs targeting 238 mRNAs was created. Subsequent pathway enrichment analysis of these mRNAs (or genes) elucidated that genes within the ‘nervous system development’ are likely mediated by miRNA regulatory mechanisms (familywise error=8.4×10⁻⁵). Herein NTF3 encodes neurotrophin-3, which controls survival and differentiation of neurons and which is closely related to the nerve growth factor.

Conclusions

By an integrated approach of miRNA and mRNA sequencing data of OA cartilage, an OA miRNA interactome and related pathways were elucidated. Our functional data demonstrated interacting levels at which miRNA affects expression of genes in the cartilage and exemplified the complexity of functionally validating a network of genes that may be targeted by multiple miRNAs.

Mesenchymal stem cell-based therapy of osteoarthritis: Current knowledge and future perspectives

Osteoarthritis (OA) is a chronic, prevalent, debilitating joint disease characterized by progressive cartilage degradation, subchondral bone remodeling, bone marrow lesions, meniscal damage, and synovitis. Innate immune cells (natural killer cells, macrophages, and mast cells) play the most important pathogenic role in the early inflammatory response, while cells of adaptive immunity (CD4 + Th1 lymphocytes and antibody producing B cells) significantly contribute to the development of chronic, relapsing course of inflammation in OA patients. Conventional therapy for OA is directed toward symptomatic treatment, mainly pain management, and is not able to promote regeneration of degenerated cartilage or to attenuate joint inflammation. Since articular cartilage, intra-articular ligaments, and menisci have no ability to heal, regeneration of these tissues remains one of the most important goals of new therapeutic approaches used for OA treatment. Due to their capacity for differentiation into chondrocytes and due to their immunomodulatory properties, mesenchymal stem cells (MSCs) have been the most extensively explored as new therapeutic agents in the cell-based therapy of OA. Simple acquisition, rapid proliferation, maintenance of differentiation potential after repeated passages in vitro, minor immunological rejection due to the low surface expression of major histocompatibility complex antigens, efficient engraftment and long-term coexistence in the host are the main characteristics of MSCs that enable their therapeutic use in OA. In this review article, we emphasized current knowledge and future perspectives regarding molecular and cellular mechanisms responsible for beneficial effects of autologous and allogeneic MSCs in the treatment of OA.

MSC-derived exosomes promote proliferation and inhibit apoptosis of chondrocytes via lncRNA-KLF3-AS1/miR-206/GIT1 axis in osteoarthritis

BACKGROUND

Exosomes secreted by human mesenchymal stem cells (hMSCs) have been shown to promote cartilage regeneration. This study aimed to explore whether exosomal lncRNA-KLF3-AS1 derived from hMSCs can promote chondrocyte proliferation via miR-206/GIT1 axis in osteoarthritis (OA).

METHODS

hMSCs and MSC-derived exosomes (MSC-exo) were prepared for morphological observation and identification by transmission electron microscopy (TEM) and flow cytometry. IL-1β-induced OA chondrocytes and collagenase-induced mouse OA model were established for the further experiments. Luciferase activity assay was performed to test whether miR-206 could bind to KLF3-AS1 or GIT1. Cell proliferation and apoptosis were evaluated by CCK-8 assay and flow cytometry, respectively.

RESULTS

MSC-Exos increased chondrogenic genes Col2a1 (type II collagen alpha 1) and aggrecan, decreased hondrocyte hypertrophy markers MMP-13 (matrix metalloproteinase-13) and Runx2 (runt-related transcription factor 2) in chondrocytes isolated from OA model mice. Furthermore, MSC-Exos attenuated IL-1β-induced chondrocyte proliferation inhibition and apoptosis induction. Moreover, MSC^KLF3-AS1-Exos (exosomes derived from KLF3-AS1-overexpressing-MSCs) ameliorated IL-1β-induced chondrocyte injury. Results also demonstrated that KLF3-AS1 acted as a competitive endogenous RNA (ceRNA) by sponging miR-206 to facilitate GIT1 expression. In addition, miR-206 overexpression and GIT1 knockdown reversed MSC^KLF3-AS1-Exos-mediated attenuation of chondrocyte injury.

CONCLUSION

Exosomal KLF3-AS1 derived from MSCs involved in MSC-Exos-mediated chondrocyte proliferation induction and chondrocyte apoptosis inhibition via miR-206/GIT1 axis. Abbreviation: G-protein-coupled receptor kinase interacting protein-1 (GIT1).

LncRNA FOXD2-AS1 regulates chondrocyte proliferation in osteoarthritis by acting as a sponge of miR-206 to modulate CCND1 expression

Recently, accumulating evidence demonstrated that the long non-coding RNAs (lncRNAs) play important roles in osteoarthritis (OA) progression. However, the role of lncRNA FOXD2-AS1 on OA is still unclear. In the present study, qRT-PCR showed that expression of FOXD2-AS1 and Cyclin D1 (CCND1) was upregulated in OA cartilage tissues, while miR-206 expression was significantly decreased. CCK-8 and colony formation assays showed that FOXD2-AS1 could promote chondrocytes viability. Flow cytometry analysis showed that FOXD2-AS1 inhibition arrested chondrocytes in G0/G1 phase and induced cells apoptosis. Furthermore, luciferase reporter assay and RIP assay showed that FOXD2-AS1 could function as a sponge of miR-206. Rescue assays showed that miR-206 inhibitors reversed the effects of FOXD2-AS1 suppression on chondrocytes viability. In addition, we identified that CCND1 acted as a direct target of miR-206. FOXD2-AS1 suppression could inhibit CCND1 expression in chondrocytes, while miR-206 inhibitors reversed CCND1 expression. Moreover, rescue assays indicated that CCND1 overexpression reversed the effects of FOXD2-AS1 suppression on chondrocytes viability. Taken together, these data indicated that FOXD2-AS1 could promote the growth of chondrocytes by targeting miR-206/CCND1 axis.