miR-139 is up-regulated in osteoarthritis and inhibits chondrocyte proliferation and migration possibly via suppressing EIF4G2 and IGF1R

Unraveling the molecular landscape of osteoarthritis: A comprehensive review focused on the role of non-coding RNAs

Osteoarthritis (OA) poses a significant global health challenge, with its prevalence anticipated to increase in the coming years. This review delves into the emerging molecular biomarkers in OA pathology, focusing on the roles of various molecules such as metabolites, noncoding RNAs (ncRNAs), including microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs). Advances in omics technologies have transformed biomarker identification, enabling comprehensive analyses of the complex pathways involved in OA pathogenesis. Notably, ncRNAs, especially miRNAs and lncRNAs, exhibit dysregulated expression patterns in OA, presenting promising opportunities for diagnosis and therapy. Additionally, the intricate interplay between epigenetic modifications and OA progression highlights the regulatory role of epigenetics in gene expression dynamics. Genome-wide association studies have pinpointed key genes undergoing epigenetic changes, providing insights into the inflammatory processes and chondrocyte hypertrophy typical of OA. Understanding the molecular landscape of OA, including biomarkers and epigenetic mechanisms, holds significant potential for developing innovative diagnostic tools and therapeutic strategies for OA management.

Intraarticular treatment with integrin α10β1-selected mesenchymal stem cells affects microRNA expression in experimental post-traumatic osteoarthritis in horses

Osteoarthritis (OA) remains a major cause of lameness in horses, which leads to lost days of training and early retirement. Still, the underlying pathological processes are poorly understood. MicroRNAs (miRNAs) are small non-coding RNAs that serve as regulators of many biological processes including OA. Analysis of miRNA expression in diseased joint tissues such as cartilage and synovial membrane may help to elucidate OA pathology. Since integrin α10β1-selected mesenchymal stem cell (integrin α10-MSC) have shown mitigating effect on equine OA we here investigated the effect of integrin α10-MSCs on miRNA expression. Cartilage and synovial membrane was harvested from the middle carpal joint of horses with experimentally induced, untreated OA, horses with experimentally induced OA treated with allogeneic adipose-derived MSCs selected for the marker integrin α10-MSCs, and from healthy control joints. miRNA expression in cartilage and synovial membrane was established by quantifying 70 pre-determined miRNAs by qPCR. Differential expression of the miRNAs was evaluated by comparing untreated OA and control, untreated OA and MSC-treated OA, and joints with high and low pathology score. A total of 60 miRNAs were successfully quantified in the cartilage samples and 55 miRNAs were quantified in the synovial membrane samples. In cartilage, miR-146a, miR-150 and miR-409 had significantly higher expression in untreated OA joints than in control joints. Expression of miR-125a-3p, miR-150, miR-200c, and miR-499-5p was significantly reduced in cartilage from MSC-treated OA joints compared to the untreated OA joints. Expression of miR-139-5p, miR-150, miR-182-5p, miR-200a, miR-378, miR-409-3p, and miR-7177b in articular cartilage reflected pathology score. Several of these miRNAs are known from research in human patients with OA and from murine OA models. Our study shows that these miRNAs are also differentially expressed in experimental equine OA, and that expression depends on OA severity. Moreover, MSC treatment, which resulted in less severe OA, also affected miRNA expression in cartilage.

MicroRNA-877-5p promotes osteoblast differentiation by targeting EIF4G2 expression

Stimulating bone formation potentially suggests therapeutics for orthopedic diseases including osteoporosis and osteoarthritis. Osteoblasts are key to bone remodeling because they act as the only bone-forming cells. miR-877-5p has a chondrocyte-improving function in osteoarthritis, but its effect on osteoblast differentiation is unknown. Here, miR-877-5p-mediated osteoblast differentiation was studied. Real-time reverse transcriptase-polymerase chain reaction was performed to measure miR-877-5p expression during the osteogenic differentiation of MC3T3-E1 cells. Osteoblast markers, including alkaline phosphatase (ALP), collagen type I a1 chain, and osteopontin, were measured and detected by alizarin red staining and ALP staining. Potential targets of miR-877-5p were predicted from three different algorithms: starBase ( http://starbase.sysu.edu.cn/ ), PITA ( http://genie.weizmann.ac.il/pubs/mir07/mir07_data.html ), and miRanda ( http://www.microrna.org/microrna/home.do ). It was further verified by dual luciferase reporter gene assay. The experimental results found that miR-877-5p was upregulated during the osteogenic differentiation of MC3T3-E1 cells. Overexpression of miR-877-5p promoted osteogenic differentiation, which was characterized by increased cell mineralization, ALP activity, and osteogenesis-related gene expression. Knockdown of miR-877-5p produced the opposite result. Dual luciferase reporter gene assay showed that miR-877-5p directly targeted eukaryotic translation initiation factor 4γ2 (EIF4G2). Overexpression of EIF4G2 inhibited osteogenic differentiation and reversed the promoting effect of overexpression of miR-135-5p on osteogenic differentiation. These results indicate that miR-877-5p might have a therapeutic application related to its promotion of bone formation through targeting EIF4G2.

Investigation of MicroRNA Biomarkers in Equine Distal Interphalangeal Joint Osteoarthritis

Osteoarthritis of the equine distal interphalangeal joint is a common cause of lameness. MicroRNAs from biofluids are promising biomarkers and therapeutic candidates. Synovial fluid samples from horses with mild and severe equine distal interphalangeal joint osteoarthritis were submitted for small RNA sequencing. The results demonstrated that miR-92a was downregulated in equine synovial fluid from horses with severe osteoarthritis and there was a significant increase in COMP, COL1A2, RUNX2 and SOX9 following miR-92a mimic treatment of equine chondrocytes in monolayer culture. This is the first equine study to evaluate the role of miR-92a in osteoarthritic chondrocytes in vitro.

Isothermal circular strand displacement-based assay for microRNA detection in liquid biopsy

Extracellular miRNAs are promising targets for developing new assays for the early diagnosis and prognosis of diseases based on liquid biopsy. The detection of miRNAs in liquid biopsies is challenged by their short sequence length, low concentration, and interferences with bodily fluid components. Isothermal circular strand displacement polymerization has emerged as a convenient method for nucleic acid amplification and detection. Herein, we describe an innovative strategy for microRNA detection directly from biological fluids based on hairpin probe–assisted isothermal amplification reaction. We designed and optimized the assay to detect target analytes in 1 µL of the complex media’s biological matrix using a microfluidic device for the straightforward analysis of multiple samples. We validated the assay to detect circulating miR-127-5p in synovial fluid, recently indicated as a predictive biomarker for osteoarthritis disease. The combined use of a mutant polymerase operating with high yield and a primer incorporating locked nucleic acid nucleosides allowed detection of miR-127-5p with 34 fmol L⁻¹ LOD. We quantified circulating miR-127-5p directly in synovial fluid, thus demonstrating that the assay may be employed for the convenient detection of 4.3 ± 0.5 pmol L⁻¹ concentrated miRNAs in liquid biopsy samples.

Long non-coding RNA MCM3AP antisense RNA 1 silencing upregulates microRNA-24-3p to accelerate proliferation and migration of vascular endothelial cells in myocardial infarction rats by reducing EIF4G2

Long non-coding RNAs (lncRNAs) are crucial drivers in the progression of human diseases such as myocardial infarction (MI). However, the impact of lncRNA MCM3AP antisense RNA 1 (MCM3AP-AS1) on MI remains unknown. This research was determined to explore the effect of MCM3AP-AS1 modulating microRNA-24-3p (miR-24-3p) and eukaryotic translation initiation factor 4 gamma 2 (EIF4G2) on MI. The rat MI models were constructed and, respectively, treated with altered MCM3AP-AS1, miR-24-3p or/and EIF4G2. Subsequently, the cardiac function, myocardial pathological injury, malondialdehyde content and superoxide dismutase activity were determined. The vascular endothelial cells (VECs) were isolated and treated severally, and then proliferation and migration of VECs were measured. MCM3AP-AS1, miR-24-3p, EIF4G2 and vascular endothelial growth factor (VEGF) expressions in myocardial tissues and VECs were assessed. MCM3AP-AS1 and EIF4G2 were upregulated while miR-24-3p and VEGF were downregulated in MI rat myocardial tissues. MCM3AP-AS1 silencing or miR-24-3p elevation improved cardiac function and myocardial pathological injury, suppressed malondialdehyde content, and also enhanced VEGF expression and superoxide dismutase activity in MI rats. In VECs, downregulated MCM3AP-AS1 or upregulated miR-24-3p accelerated cell proliferation and migration. These effects of miR-24-3p upregulation were reversed by overexpressed EIF4G2. Our study summarizes that reduced MCM3AP-AS1 elevates miR-24-3p to promote proliferation and migration of MI rat VECs by inhibiting EIF4G2.

miR-125a-5p-abundant exosomes derived from mesenchymal stem cells suppress chondrocyte degeneration via targeting E2F2 in traumatic osteoarthritis

miRNAs are broad participants in vertebrate biological processes, and they are also the major players in pathological processes. miR-125a-5p was recently found a modulator in the progression of osteoarthritis (OA). Our study was aimed to explore the role and underlying mechanisms of miR-125a-5p-abundant exosomes derived from mesenchymal stem cells (MSC) on OA progression. We separated bone marrow mesenchymal stem cells (BMSCs) as well as the exosomes from traumatic OA patients. The immunofluorescence and cartilage staining were implemented for the observation and the assessment on endocytosis of chondrocytes and exosomal miR-125a-5p efficacy to cartilage degradation. Dual luciferase reporter assay was performed to verified the relationship between miR-125a-5p and E2F2. Then, the function of exosomal miR-125a-5p were examined on chondrocyte degeneration in vitro and in vivo. Our findings indicated that E2F2 expression was elevated while the miR-125a-5p was down in traumatic OA cartilage tissue, showing a negative correlation of the former and the latter. miR-125a-5p targets E2F2 in traumatic OA cartilage tissue and leads to the down-expression of E2F2. The E2F2 expression in chondrocytes was decreased after internalization of exosomes. We additionally found that BMSCs-derived exosomes were rich in miR-125a-5p content and chondrocytes can have it internalized. miR-125a-5p is endowed with a trait of accelerating chondrocytes migration, which is going along with the up-expressions of Collagen II, aggrecan and SOX9 and the down-expression of MMP-13 in vitro. Besides that, the mice model with post-traumatic OA turned out that exosomal miR-125a-5p might beget an alleviation in chondrocyte extracellular matrix degradation. All these outcomes revealed that BMSCs-derived exosomal miR-125a-5p is a positive regulator for chondrocyte migration and inhibit cartilage degeneration We thus were reasonable to believe that transferring of exosomal miR-125a-5p is a prospective strategy for OA treatment.

The Fibroblast-Like Synoviocyte Derived Exosomal Long Non-coding RNA H19 Alleviates Osteoarthritis Progression Through the miR-106b-5p/TIMP2 Axis

Osteoarthritis (OA) is a common degenerative joint disease that affects people worldwide. The interaction between fibroblast-like synoviocytes (FLSs) and chondrocytes may play a vital role in OA disease pathology. However, the underlying mechanisms by which FLSs exert regulatory effects on chondrocytes still need to be elucidated. Exosomes, small membrane vesicles secreted from living cells, are known to play a variety of roles in mediating cell-to-cell communication through the transferring of biological components such as non-coding RNAs and proteins. Here, we investigate the cellular processes of chondrocytes regulated by FLS-derived exosomes and the mechanisms of action underlying the functions of exosomes in OA pathogenesis. We observed that exosome-mediated cartilage repair was characterized by increased cell viability and migration as well as alleviated matrix degradation. Using chondrocyte cultures, the enhanced cellular proliferation and migration during exosome-mediated cartilage repair was linked to the exosomal lncRNA H19-mediated regulation of the miR-106b-5p/TIMP2 axis. Transfection of miR-106-5p mimics in chondrocytes significantly decreased cell proliferation and migration, promoted matrix degradation characterized by elevated MMP13 and ADAMTS5 expression, and reduced the expression of COL2A1 and ACAN in chondrocytes. Furthermore, we found that TIMP2 was directly regulated by miR-106-5p. Co-transfections of miR-106-5p mimics and TIMP2 resulted in higher levels of COL2A1 and ACAN, but lower levels of MMP13 and ADAMTS5. Together, these observations demonstrated that the lncRNA H19 may promote chondrocyte proliferation and migration and inhibit matrix degradation in OA possibly by targeting the miR-106b-5p/TIMP2 axis. In the future, H19 may serve as a potential therapeutic target for the treatment of OA.

Long noncoding RNA lnc-NAP sponges mmu-miR-139-5p to modulate Nanog functions in mouse ESCs and embryos

The pluripotency of embryonic stem cells (ESCs) is controlled by a multilayer regulatory network, of which the key factors include core pluripotency genes Oct4, Sox2 and Nanog, and multiple microRNAs (miRNAs). Recently, long noncoding RNAs (lncRNAs) have been discovered as a class of new regulators for ESCs, and some lncRNAs could function as competing endogenous RNAs (ceRNAs) to regulate mRNAs by competitively binding to miRNAs. Here, we identify mmu-miR-139-5p as a new regulator for Nanog by targeting Nanog 3' untranslated region (UTR) to repress Nanog expression in mouse ESCs and embryos. Such regulation could be released by an ESC-specifically expressed ceRNA named lnc-NAP. The expression of lnc-NAP is activated by OCT4, SOX2, as well as NANOG through promoter binding. Downregulation of lnc-NAP reduces Nanog abundance, which leads to decreased pluripotency of mouse ESCs and embryonic lethality. These results reveal lnc-NAP as a new regulator for Nanog in mouse ESCs, and uncover a feed-forward regulatory loop of Nanog through the participation of lnc-NAP.

MicroRNA-197 regulates chondrocyte proliferation, migration, and inflammation in pathogenesis of osteoarthritis by targeting EIF4G2

Recent studies have demonstrated that microRNAs (miRNAs) are involved in many pathological conditions including osteoarthritis (OA). In the present study, we aimed to investigate the role of miR-197 in OA and the potential molecular mechanism. The expression levels of miR-197 were detected by quantitative real-time PCR analysis. Cell proliferation and migration abilities were performed by 3-(4,5-dimethylthiazol-2-yl)-2,5-di-phenyltetrazolium bromide and transwell assays. The concentrations of inflammatory cytokines, including IL-1β, IL-6, and TNF-α, were detect using ELISA assay. Furthermore, luciferase reporter and rescue assays were applied to identify the functional target gene of miR-197 in OA. The results showed that miR-197 expression was significantly down-regulated in the OA cartilage tissues compared with normal cartilage tissues, accompanied by up-regulation of EIF4G2 expression. An inverse correlation was found between EIF4G2 and miR-197 expressions in OA cartilage tissues. Treatment with miR-197 mimics promoted the growth and migration abilities of chondrocytes, while miR-197 inhibitors induced the opposite effects. Furthermore, restoration of miR-197 significantly decreased IL-1β, IL-6, and TNF-α expression, whereas knockdown of miR-197 led to a induction in these inflammatory mediators. Moreover, EIF4G2 was predicted and confirmed as a directly target of miR-197. Overexpressed miR-197 could down-regulate EIF4G2 expression in chondrocytes, while miR-197 knockdown could elevate EIF4G2 expression. Additionally, EIF4G2 overexpression reversed the effects of miR-197 mimics on chondrocytes proliferation, migration, and inflammation. Taken together, our study demonstrated that miR-197 promotes chondrocyte proliferation, increases migration, and inhibits inflammation in the pathogenesis of OA by targeting EIF4G2, indicating the potential therapeutic targets of the miR-197/EIF4G2 axis for OA treatment.

LncRNA SDHAP1 confers paclitaxel resistance of ovarian cancer by regulating EIF4G2 expression via miR-4465

Ovarian cancer has ranked as one of the leading causes of female morbidity and mortality around the world, which affects ∼239,000 patients and causes 152,000 deaths every year. Chemotherapeutic resistance of ovarian cancer remains a devastating actuality in clinic. The aberrant upregulation of long non-coding RNA succinate dehydrogenase complex flavoprotein subunit A pseudogene 1 (lncRNA SDHAP1) in the Paclitaxel (PTX)-resistant ovarian cancer cell lines has been reported. However, studies focussed on SDHAP1 in its regulatory function of chemotherapeutic resistance in ovarian cancer are limited, and the detailed mechanisms remain unclear. In this study, we demonstrated that SDHAP1 was upregulated in PTX-resistant SKOV3 and Hey-8 ovarian cancer cell lines while the level of miR-4465 was downregulated. Knocking-down SDHAP1 induced re-acquirement of chemo-sensitivity to PTX in ovarian cancer cells in vitro. Mechanically, SDHAP1 upregulated the expression of EIF4G2 by sponging miR-4465 and thus facilitated the PTX-induced apoptosis in ovarian cancer cells. The regulation network involving SDHAP1, miR-4465 and EIF4G2 could be a potential therapy target for the PTX-resistant ovarian cancer.

Inhibition of miR-139-5p by topical JTXK gel promotes healing of Staphylococcus aureus-infected skin wounds

BACKGROUND

The inflammatory skin wound response is regulated by argonaute 2-bound microRNAs (Ago2-miRNAs) such as miR-139-5p, which inhibit transcription of their target mRNAs. Jiang Tang Xiao Ke (JTXK) is a traditional Chinese medicine that reduces miR-139-5p expression, suggesting that topical application of JTXK may have effects on wound healing.

METHODS

miR-139^-/- mice and wild-type (WT) mice were employed to characterize the in vivo effects of miR-139-5p on sterile wound healing. Neutrophil migration and activation into the wound site were examined by live imaging analysis in lys-EGFP mice and myeloperoxidase/aminophenyl fluorescein assays, respectively. In silico and in vitro studies in differentiated HL60 cells were performed to identify miR-139-5p's downstream mediator(s). miR-139^-/- neutrophil transplantation (with or without Eif4g2-knockdown rescue) or a topical JTXK gel preparation (with or without miR-139-5p mimic rescue) were employed to characterize the in vivo effects of miR-139-5p and JTXK, respectively, on Staphylococcus aureus (S. aureus)-infected wound healing.

RESULTS

miR-139^-/- mice display impaired sterile wound healing but improved S. aureus-infected wound healing. Eif4g2, a protein that supports neutrophil proliferation and differentiation, was identified as a key downstream mediator of miR-139-5p. miR-139^-/- mice show elevated neutrophilic activation and Eif4g2 upregulation. miR-139^-/- neutrophils enhanced S. aureus-infected wound healing in an Eif4g2-dependent manner. Moreover, topical JTXK gel therapy also enhanced S. aureus-infected wound healing in a miR-139-5p-dependent manner.

CONCLUSIONS

miR-139-5p negatively regulates the neutrophilic response during S. aureus-infected wound healing, suggesting that JTXK or other miR-139-5p suppressants may be effective for treating infected skin wounds.

Equine synovial fluid small non-coding RNA signatures in early osteoarthritis

BACKGROUND

Osteoarthritis remains one of the greatest causes of morbidity and mortality in the equine population. The inability to detect pre-clinical changes in osteoarthritis has been a significant impediment to the development of effective therapies against this disease. Synovial fluid represents a potential source of disease-specific small non-coding RNAs (sncRNAs) that could aid in the understanding of the pathogenesis of osteoarthritis. We hypothesised that early stages of osteoarthritis would alter the expression of sncRNAs, facilitating the understanding of the underlying pathogenesis and potentially provide early biomarkers.

METHODS

Small RNA sequencing was performed using synovial fluid from the metacarpophalangeal joints of both control and early osteoarthritic horses. A group of differentially expressed sncRNAs was selected for further validation through qRT-PCR using an independent cohort of synovial fluid samples from control and early osteoarthritic horses. Bioinformatic analysis was performed in order to identify putative targets of the differentially expressed microRNAs and to explore potential associations with specific biological processes.

RESULTS

Results revealed 22 differentially expressed sncRNAs including 13 microRNAs; miR-10a, miR-223, let7a, miR-99a, miR-23b, miR-378, miR-143 (and six novel microRNAs), four small nuclear RNAs; U2, U5, U11, U12, three small nucleolar RNAs; U13, snoR38, snord96, and one small cajal body-specific RNA; scarna3. Five sncRNAs were validated; miR-223 was significantly reduced in early osteoarthritis and miR-23b, let-7a-2, snord96A and snord13 were significantly upregulated. Significant cellular actions deduced by the differentially expressed microRNAs included apoptosis (P < 0.0003), necrosis (P < 0.0009), autophagy (P < 0.0007) and inflammation (P < 0.00001). A conservatively filtered list of 57 messenger RNA targets was obtained; the top biological processes associated were regulation of cell population proliferation (P < 0.000001), cellular response to chemical stimulus (P < 0.000001) and cell surface receptor signalling pathway (P < 0.000001).

CONCLUSIONS

Synovial fluid sncRNAs may be used as molecular biomarkers for early disease in equine osteoarthritic joints. The biological processes they regulate may play an important role in understanding early osteoarthritis pathogenesis. Characterising these dynamic molecular changes could provide novel insights on the process and mechanism of early osteoarthritis development and is critical for the development of new therapeutic approaches.

Identification of key genes in osteoarthritis using bioinformatics, principal component analysis and meta-analysis

The present study aimed to identify key genes involved in osteoarthritis (OA). Based on a bioinformatics analysis of five gene expression profiling datasets (GSE55457, GSE55235, GSE82107, GSE12021 and GSE1919), differentially expressed genes (DEGs) in OA were identified. Subsequently, a protein-protein interaction (PPI) network was constructed and its topological structure was analyzed. In addition, key genes in OA were identified following a principal component analysis (PCA) based on the DEGs in the PPI network. Finally, the functions and pathways enriched by these key genes were also analyzed. The PPI network consisted of 241 nodes and 576 interactives, including a total of 171 upregulated DEGs [e.g., aspartylglucosaminidase (AGA), CD58 and CD86] and a total of 70 downregulated DEGs (e.g., acetyl-CoA carboxylase β and dihydropyrimidine dehydrogenase). The PPI network complied with an attribute of scale-free small-world network. After PCA, 47 key genes were identified, including β-1,4-galactosyltransferase-1 (B4GALT1), AGA, CD58, CD86, ezrin, and eukaryotic translation initiation factor 4 γ 1 (EIF4G1). Subsequently, the 47 key genes were identified to be enriched in 13 Gene Ontology (GO) terms and 2 Kyoto Encyclopedia of Genes and Genomes pathways, with the GO terms involving B4GALT1 including positive regulation of developmental processes, protein amino acid terminal glycosylation and protein amino acid terminal N-glycosylation. In addition, B4GALT1 and EIF4G1 were confirmed to be downregulated in OA samples compared with healthy controls, but only EIF4G1 was determined to be significantly downregulated in OA samples, as determined via a meta-analysis of the 5 abovementioned datasets. In conclusion, B4GALT1 and EIF4G1 were indicated to have significant roles in OA, and B4GALT1 may be involved in positive regulation of developmental processes, protein amino acid terminal glycosylation and protein amino acid terminal N-glycosylation. The present study may enhance the current understanding of the molecular mechanisms of OA and provide novel therapeutic targets.

Mesenchymal stem cell-derived exosomal microRNA-136-5p inhibits chondrocyte degeneration in traumatic osteoarthritis by targeting ELF3

BACKGROUND

Emerging evidence suggests that microRNAs (miRs) are associated with the progression of osteoarthritis (OA). In this study, the role of exosomal miR-136-5p derived from mesenchymal stem cells (MSCs) in OA progression is investigated and the potential therapeutic mechanism explored.

METHODS

Bone marrow mesenchymal stem cells (BMMSCs) and their exosomes were isolated from patients and identified. The endocytosis of chondrocytes and the effects of exosome miR-136-5p on cartilage degradation were observed and examined by immunofluorescence and cartilage staining. Then, the targeting relationship between miR-136-5p and E74-like factor 3 (ELF3) was analyzed by dual-luciferase report assay. Based on gain- or loss-of-function experiments, the effects of exosomes and exosomal miR-136-5p on chondrocyte migration were examined by EdU and Transwell assay. Finally, a mouse model of post-traumatic OA was developed to evaluate effects of miR-136-5p on chondrocyte degeneration in vivo.

RESULTS

In the clinical samples of traumatic OA cartilage tissues, we detected increased ELF3 expression, and reduced miR-136-5p expression was determined. The BMMSC-derived exosomes showed an enriched level of miR-136-5p, which could be internalized by chondrocytes. The migration of chondrocyte was promoted by miR-136-5p, while collagen II, aggrecan, and SOX9 expression was increased and MMP-13 expression was reduced. miR-136-5p was verified to target ELF3 and could downregulate its expression. Moreover, the expression of ELF3 was reduced in chondrocytes after internalization of exosomes. In the mouse model of post-traumatic OA, exosomal miR-136-5p was found to reduce the degeneration of cartilage extracellular matrix.

CONCLUSION

These data provide evidence that BMMSC-derived exosomal miR-136-5p could promote chondrocyte migration in vitro and inhibit cartilage degeneration in vivo, thereby inhibiting OA pathology, which highlighted the transfer of exosomal miR-136-5p as a promising therapeutic strategy for patients with OA.

Down-regulation of MiR-138-5p Protects Chondrocytes ATDC5 and CHON-001 from IL-1 β-induced Inflammation Via Up-regulating SOX9

BACKGROUND

Osteoarthritis (OA) pertains to a chronic disease of degenerative joints distinguished by articular cartilage destruction, subchondral bone remodeling, osteophyte formation, and inflammatory changes. Chondrocyte apoptosis is inextricably linked to cartilage degeneration. SRY-related high-mobility-group-box 9 (SOX9) is a well-acknowledged transcription factor in the chondrogenesis. Nevertheless, the detailed function of miR-138-5p/SOX9 in OA remains to be fully clarified.

MATERIALS AND METHODS

qRT-PCR was performed to measure the expressions of miR-138-5p and SOX9 mRNA in OA and normal cartilage tissues and cells. Human chondrocyte cell lines, CHON-001 and ATDC5, were treated with different doses of interleukin-1β (IL-1β) to simulate the inflammatory response environment of OA. miR-138-5p mimics, miR-138-5p inhibitors, and SOX9 small interfering RNA (siRNA) were constructed and transfected into CHON-001 and ATDC5 cells. CCK-8 was conducted to determine the cell viability and transwell assay was used to monitor the migration of cells. Western blot was carried out to detect the expressions of apoptosis- related factors. Enzyme-linked immunosorbent assay (ELISA) was adopted to measure the contents of inflammatory factors. TargetScan predicted SOX9 was a target gene of miR-138-5p, which was then verified by luciferase assay.

RESULTS

miR-138-5p expression was down-regulated in OA and regulated SOX9 expression. The downregulation of miR-138-5p facilitated the proliferation and migration of CHON-001 and ATDC5 cells, while impeded their apoptosis and inflammatory response. Besides, down-regulated SOX9 can counteract the promoting effect of down-regulated miR-138-5p on the proliferation and migration of chondrocytes.

CONCLUSION

miR-138-5p can arrest the proliferation and migration of CHON-001 and ATDC5 via restraining SOX9, and facilitate the apoptosis and inflammation. This study revealed the protective effect of down-regulated miR-138-5p on the inflammatory injury of chondrocytes caused by IL-1β.

Exosomes in intercellular communication and implications for osteoarthritis

Osteoarthritis (OA) is the most prevalent of the musculoskeletal conditions and represents a significant public health burden. While degeneration of articular cartilage is a key feature, it is now increasingly recognized as a complex condition affecting the whole joint, with synovial inflammation present in a significant proportion of patients. As a secretory tissue, the OA synovium is a rich source of both soluble inflammatory mediators and extracellular vesicles, including exosomes, which have been implicated in cell-cell communication. Exosome cargo has been found to include proteins, lipids and various RNA subtypes such as mRNA and miRNA, potentially capable of regulating gene expression in target cells and tissues. Profiling of exosome cargo and understanding effects on cartilage could elucidate novel regulatory mechanisms within the joint, providing insight for targeted treatment. The aim of this article is to review current literature on exosome biology, highlighting the relevance and application for OA pathogenesis.

Scaffold-Based Gene Therapeutics for Osteochondral Tissue Engineering

Significant progress in osteochondral tissue engineering has been made for biomaterials designed to deliver growth factors that promote tissue regeneration. However, due to diffusion characteristics of hydrogels, the accurate delivery of signaling molecules remains a challenge. In comparison to the direct delivery of growth factors, gene therapy can overcome these challenges by allowing the simultaneous delivery of growth factors and transcription factors, thereby enhancing the multifactorial processes of tissue formation. Scaffold-based gene therapy provides a promising approach for tissue engineering through transfecting cells to enhance the sustained expression of the protein of interest or through silencing target genes associated with bone and joint disease. Reports of the efficacy of gene therapy to regenerate bone/cartilage tissue regeneration are widespread, but reviews on osteochondral tissue engineering using scaffold-based gene therapy are sparse. Herein, we review the recent advances in gene therapy with a focus on tissue engineering scaffolds for osteochondral regeneration.

Association of circulating microRNAs with prevalent and incident knee osteoarthritis in women: the OFELY study

Objectives

In the context of the scarcity of biomarkers for knee osteoarthritis (OA), we examined the associations of prevalent and incident OA with the expression levels of serum miRNAs in subjects with and without OA.

Methods

With a next-generation sequencing approach, we compared the miRome expression of 10 women with knee OA and 10 age-matched healthy subjects. By real-time qPCR, we analyzed the expression levels of 19 miRNAs at baseline selecting 43 women with prevalent knee OA (Kellgren Lawrence score of 2/3), 23 women with incident knee OA over a 4-year follow-up and 67 healthy subjects without prevalent or incident OA matched for age and body mass index.

Results

Serum miR-146a-5p was significantly increased in the group of prevalent knee OA compared with controls (relative quantification (RQ); median [Interquartile range] 1.12 [0.73; 1.46] vs 0.85 [0.62; 1.03], p = 0.015). The likelihood of prevalent knee OA was significantly increased (odds ratio [95% confidence interval (CI)] 1.83 [1.21–2.77], p = 0.004) for each quartile increase in serum miR-146a-5p. The women with miR-146a-5p levels above the median (0.851) had a higher risk of prevalent knee OA compared to those below the median [95% CI] 4.62 [1.85–11.5], p = 0.001. Moreover, we found a significant association between the baseline level of serum miR-186-5p and the risk of incident knee OA (Q4 vs Q1–3; odds ratio [95% CI] 6.13 [1.14–32.9], p = 0.034).

Conclusion

We showed for the first time that miR-146a-5p and miR-186-5p are significantly associated with prevalent and incident knee OA, respectively.

MicroRNA-139-5p modulates the growth and metastasis of malignant melanoma cells via the PI3K/AKT signaling pathway by binding to IGF1R

The relation between microRNAs (miRNAs) and malignant melanoma has been demonstrated in previous studies, while there was little research about miR-139-5p and malignant melanoma. The aim of this study is to investigate the ability of miR-139-5p in malignant melanoma cells via the modulation of the PI3K/AKT signaling pathway by targeting IGF1R. MiR-139-5p expression in malignant melanoma tissues and 5 malignant melanoma cell lines was detected. The melanoma cells were transfected with miR-139-5p mimic negative control (NC) sequence, miR-139-5p mimic, IGF1R overexpressed recombinant plasmid NC or IGF1R overexpressed sequence. The expression of Akt signaling pathway-related protein was evaluated. The biological functions in malignant melanoma cells were evaluated by a string of experiments. MiR-139-5p expressed a poor level in tissues and cell lines of malignant melanoma. Overexpressed miR-139-5p suppressed the cell proliferation, migration, and invasion, and contributed to the promoted apoptosis of malignant melanoma cells by decreasing IGF1R. MiR-139-5p down-regulated the IGF1R expression, and IGF1R accelerated the activation of the PI3K/AKT signaling pathway. miR-139-5p reversed the promotive impacts of IGF1R on the PI3K/AKT signaling pathway. The study validates that miR-139-5p could suppress malignant melanoma progression through the repression of the PI3K/AKT signaling pathway by down-regulating IGF1R. Therefore, miR-139-5p could pave a new way for the treatment of malignant melanoma.

Downregulated miR‑302d‑3p promotes chondrocyte proliferation and migration by regulation of Unc‑51‑like kinase 1

Osteoarthritis (OA) is a common musculoskeletal disease and is related to the function of chondrocytes. The aim of the present study was to investigate the effects of miR-302d-3p on chondrocytes. Quantitative PCR (qPCR) was conducted to detect mRNA expression, while western blotting was performed to investigate protein expression in these cells. RNAs mimics, inhibitors and small interfering (si)RNAs were respectively transfected into chondrocytes (CHON-001 cell line), after which, a Cell Counting Kit-8 assay was performed to detect chondrocyte viability. Giemsa staining of the cells was also conducted to analyze the colony formation ability of the cells. Additionally, cell apoptosis was evaluated with an apoptosis detection kit using flow cytometry. A scratch-wound assay was conducted to investigate cell migration. Bioinformatics analysis using TargetScan 7.2 revealed the potential the target gene of microRNA (miR)-302d-3p; a dual luciferase reporter assay determined the target gene. Suppression of miR-302d-3p increased the viability of cells, cell colony number and migration; CHON-001 cell apoptosis was also inhibited. miR-302d-3p mimics decreased the luciferase activity of reporter plasmids containing the wild-type 3′-untranslated region of Unc-51-like kinase 1 (ULK1). siULK1 decreased CHON-001 cell viability and migration. Furthermore, siULK1 promoted the expression of phosphorylated IκBα and p65, while miR-302d-3p inhibitor suppressed the expression of phosphorylated IκBα and p65. Inhibition of miR-302d-3p could promote the proliferation and migration, and inhibit the apoptosis of chondrocytes, potentially by upregulating ULK1; thus, inflammation may be suppressed. The findings of the present study suggest miR-302d-3p and ULK1 as potential therapeutic targets for the prevention and treatment of OA.

FAM3A protects chondrocytes against interleukin-1β-induced apoptosis through regulating PI3K/Akt/mTOR pathway

Chondrocyte death due to apoptosis is central for osteoarthritis (OA) pathogenesis. The family with sequence similarity 3A (FAM3A) is a mitochondrial protein that plays an important role for cellular adaptation to stress and cell survival. Yet, whether FAM3A is associated with chondrocyte apoptosis and OA pathogenesis remains uncharacterized. In this study, we found that FAM3A expression was downregulated in cartilage tissue from an experimental OA mouse model. Besides, FAM3A expression was also reduced in chondrocytes treated with interleukin-1β (IL-1β), an inflammatory cytokine that promotes cartilage degradation. Moreover, we discovered that FAM3A attenuated chondrocyte apoptosis induced by IL-1β treatment in vitro, suggesting a protective effect of FAM3A against chondrocyte apoptosis. Moreover, mechanistically, FAM3A activated PI3K/Akt/mTOR pathway in IL-1β-treated chondrocytes, and blockade of PI3K/Akt/mTOR pathway with specific inhibitors, wortmannin and LY294002, diminished FAM3A effect on IL-1β-induced chondrocyte apoptosis, hence demonstrating that FAM3A attenuates IL-1β-induced chondrocyte apoptosis through activating the pro-survival PI3K/Akt/mTOR pathway. In conclusion, our study may identify FAM3A as a potential regulator of chondrocyte apoptosis involved in OA pathogenesis.

Identify CRNDE and LINC00152 as the key lncRNAs in age-related degeneration of articular cartilage through comprehensive and integrative analysis

Background

Osteoarthritis (OA) is one of the most important age-related degenerative diseases, and the leading cause of disability and chronic pain in the aging population. Recent studies have identified several lncRNA-associated functions involved in the development of OA. Because age is a key risk factor for OA, we investigated the differential expression of age-related lncRNAs in each stage of OA.

Methods

Two gene expression profiles were downloaded from the GEO database and differentially expressed genes (DEGs) were identified across each of the different developmental stages of OA. Next, gene ontology (GO) functional and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were performed to annotate the function of the DEGs. Finally, a lncRNA-targeted DEG network was used to identify hub-lncRNAs.

Results

A total of 174 age-related DEGs were identified. GO analyses confirmed that age-related degradation was strongly associated with cell adhesion, endodermal cell differentiation and collagen fibril organization. Significantly enriched KEGG pathways associated with these DEGs included the PI3K–Akt signaling pathway, focal adhesion, and ECM–receptor interaction. Further analyses via a protein–protein interaction (PPI) network identified two hub lncRNAs, CRNDE and LINC00152, involved in the process of age-related degeneration of articular cartilage. Our findings suggest that lncRNAs may play active roles in the development of OA. Investigation of the gene expression profiles in different development stages may supply a new target for OA treatment.

Transcriptome analyses identify key genes and potential mechanisms in a rat model of osteoarthritis

BACKGROUND

Osteoarthritis (OA) is one of the most common degenerative diseases of the joints worldwide, but still the pathogenesis of OA is largely unknown. The purpose of our study is to clarify key candidate genes and relevant signaling pathways in a surgical-induced OA rat model.

METHODS

The microarray raw data of GSE8077 was downloaded from GEO datasets. GeoDiver were employed to screen differentially-expressed genes (DEGs). Enrichment analyses of DEGs were performed using Metascape. Construction of protein-protein interaction (PPI) network and identification of key genes were conducted using STRING, Cytoscape v3.6.0, and Centiscape2.2. Furthermore, miRDB and Cytoscape v3.6.0 were used for visualization of miRNA-mRNA regulatory network. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis for predicted miRNAs was undertaken using DIANA-miRPath v3.0.

RESULTS

Several DEGs (188 in comparison between OA and sham-operated group and 160 in comparison between OA and contralateral group) were identified. DEGs mainly enriched in vasculature development, regulation of cell migration, response to growth factor (Gene ontology), and ECM-receptor interaction (KEGG). Two comparison cohorts shared 79 intersection genes, and of these, Ccl2, Col4a1, Col1a1, Aldh1a3, and Itga8 were defined as the hub genes. Predicted miRNAs of seven DEGs from sub-networks mainly enriched in MAPK signaling pathway.

CONCLUSION

The current study shows that some key genes and pathways, such as Ccl2, Col4a1, Col1a1, Aldh1a3, Itga8, ECM-receptor interaction, and MAPK signaling pathway may be associated with OA progression and act as potential biomarkers and therapeutic targets for OA.

The complex landscape of microRNAs in articular cartilage: biology, pathology, and therapeutic targets

The disabling degenerative disease osteoarthritis (OA) is prevalent among the global population. Articular cartilage degeneration is a central feature of OA; therefore, a better understanding of the mechanisms that maintain cartilage homeostasis is vital for developing effective therapeutic interventions. MicroRNAs (miRs) modulate cell signaling pathways and various processes in articular cartilage via posttranscriptional repression of target genes. As dysregulated miRs frequently alter the homeostasis of articular cartilage, modulating select miRs presents a potential therapeutic opportunity for OA. Here, we review key miRs that have been shown to modulate cartilage-protective or -destructive mechanisms and signaling pathways. Additionally, we use an integrative computational biology approach to provide insight into predicted miR gene targets that may contribute to OA pathogenesis, and highlight the complexity of miR signaling in OA by generating both unique and overlapping gene targets of miRs that mediate protective or destructive effects. Early OA detection would enable effective prevention; thus, miRs are being explored as diagnostic biomarkers. We discuss these ongoing efforts and the applicability of miR mimics and antisense inhibitors as potential OA therapeutics.

Plasma miR-136 can be used to screen patients with knee osteoarthritis from healthy controls by targeting IL-17

The current study mainly evaluated the plasma level of microRNA (miR)-136 in knee osteoarthritis (KOA) patients and determined if miR-136 could be used as a potential biomarker to screen KOA patients from healthy controls. It was demonstrated that plasma miR-136 was significantly decreased in the plasma of KOA patients. Moreover, the reduction in plasma miR-136 negatively correlated with the severity of KOA. Additionally, the increase in the serum interleukin (IL)-17 level positively correlated with the severity of KOA. More importantly, dual luciferase assays and western blot assays indicated that IL-17 was a target gene of miR-136. Further analysis showed that plasma miR-136 could be used as a biomarker to screen KOA patients from healthy controls. In summary, for the first time, the present study revealed that through targeting IL-17, decreased plasma miR-136 levels could be used as a potential biomarker to screen KOA patients from healthy controls.

MicroRNAs and Osteoarthritis

An imbalance in gene expressional events skewing chondrocyte anabolic and catabolic pathways toward the latter causes an aberrant turnover and loss of extracellular matrix proteins in osteoarthritic (OA) articular cartilage. Thus, catabolism results in the elevated loss of extracellular matrix proteins. There is also evidence of an increase in the frequency of chondrocyte apoptosis that compromises the capacity of articular cartilage to undergo repair. Although much of the fundamental OA studies over the past 20 years identified and characterized many genes relevant to pro-inflammatory cytokines, apoptosis, and matrix metalloproteinases (MMPs)/a disintegrin and metalloproteinase with thrombospondin motif (ADAMTS), more recent studies focused on epigenetic mechanisms and the associated role of microRNAs (miRs) in regulating gene expression in OA cartilage. Thus, several miRs were identified as regulators of chondrocyte signaling pathways, apoptosis, and proteinase gene expression. For example, the reduced expression of miR-146a was found to be coupled to reduced type II collagen (COL2) in OA cartilage, whereas MMP-13 levels were increased, suggesting an association between MMP-13 gene expression and COL2A1 gene expression. Results of these studies imply that microRNAs could become useful in the search for diagnostic biomarkers, as well as providing novel therapeutic targets for intervention in OA.

The Involvement of MicroRNAs in Osteoarthritis and Recent Developments: A Narrative Review

Background:

Osteoarthritis (OA) is the most common chronic joint disease and it may progressively cause disability and compromise quality of life. Lately, the role of miRNAs in the pathogenesis of OA has drawn a lot of attention. miRNAs are small, single-stranded, non-coding molecules of RNA which regulate gene expression at post-transcriptional level. The dysregulation of the expression of several miRNAs affects pathways involved in OA pathogenesis.

Objective:

The purpose of this article is to review the literature on the involvement of miRNAs in the pathogenesis of OA and the implications on its diagnosis and treatment.

Materials and Methods:

An extensive electronic literature search was conducted by two researchers from January 2008 to August 2017. Titles and abstracts of papers were screened by the authors for further inclusion in the present work. Finally, full texts of the selected articles were retrieved.

Results:

Abnormally expressed miRNAs enhance the production of cartilage degrading enzymes, inhibit the expression of cartilage matrix components, increase the production of proinflammatory cytokines, facilitate chondrocyte apoptosis, suppress autophagy in chondrocytes and are involved in pain-related pathways. miRNAs are also incorporated in extra-cellular membranous vesicles such as exosomes and participate in the intercellular communication in osteoarthritic joints.

Conclusion:

Ongoing research on miRNAs has potential implications in the diagnosis and treatment of OA. Their different levels in peripheral blood and synovial fluid between OA patients and healthy population makes them candidates for being used as biomarkers of the disease, while targeting miRNAs may be a novel therapeutic strategy in OA.

Downregulation of microRNA-448 inhibits IL-1β-induced cartilage degradation in human chondrocytes via upregulation of matrilin-3

Background

Osteoarthritis is characterized by the continuous degradation of the articular cartilage. The microRNA miR-448 has been found to be broadly involved in cellular processes, including proliferation, apoptosis, invasion and EMT. While aberrant expression of miR-448 has been found in multiple cancers, its level in osteoarthritis cartilage and its role in the progression of this disease are still unknown. Here, we examined the functional roles of miR-448 and its expression in osteoarthritis tissues, including IL-1β-stimulated osteoarthritis chondrocytes.

Methods

Chondrocytes were isolated from human articular cartilage and stimulated with IL-1β. The expression levels of miR-448 in the cartilage and chondrocytes were both determined. After transfection with an miR-448 mimic or inhibitor, the mRNA levels of aggrecan, type II collagen and MMP-13 were determined. Luciferase reporter assay, qRT-PCR and western blot were performed to explore whether matrilin-3 was a target of miR-448. Furthermore, we co-transfected chondrocytes with miR-448 inhibitor and siRNA for matrilin-3 and then stimulated them with IL-1β to determine whether miR-448-mediated IL-1β-induced cartilage matrix degradation resulted from directly targeting matrilin-3.

Results

The level of miR-448 was significantly higher and matrilin-3 expression was significantly lower in osteoarthritis cartilage and IL-1β-induced chondrocytes than in normal tissues and cells. Furthermore, matrilin-3 expression was reduced by miR-448 overexpression. MiR-448 downregulation significantly alleviated the IL-1β-induced downregulation of aggrecan and type II collagen expression, and upregulation of MMP-13 expression. MiR-448 overexpression had the opposite effects. Knockdown of matrilin-3 reversed the effects of the miR-448 inhibitor on the expressions of aggrecan, type II collagen and MMP-13.

Conclusion

The findings showed that miR-448 contributed to the progression of osteoarthritis by directly targeting matrilin-3. This indicates that it has potential as a therapeutic target for the treatment of osteoarthritis.

MicroRNA-17-5p contributes to osteoarthritis progression by binding p62/SQSTM1

Autophagy has been reported to be widely involved in the pathogenesis of osteoarthritis (OA). Increasing evidence suggested the important role of microRNAs (miRs) in the progression of OA. However, the functional role of miR-17-5p in OA development has remained to be fully elucidated. First, a mouse model of OA was established and the relative level of miR-17-5p was determined using PCR. Safranin O-fast green staining was applied to determine cartilage degeneration. TargetScan software and a dual luciferase reporter assay were applied to determine potential target genes of miR-17-5P. Autophagy measurement was performed using green fluorescent protein-microtubule-associated protein 1 light chain 3 (LC3) dot analysis. The results demonstrated that the relative expression of miR-17-5p was significantly decreased in OA model mice. In addition, the level of miR-17-5p was decreased in SW1353 human chondrosarcoma cells treated with interleukin-1β. Furthermore, autophagy was found to be suppressed in the knee joints of experimental OA model mice. The dual luciferase reporter assay confirmed that p62/sequestosome 1 was a target gene of miR-17-5p. Of note, miR-17-5p inhibitor-induced reduction of LC3 dots was markedly reversed by knockdown of p62 in SW1353 cells. In conclusion, decreased miR-17-5p expression in chondrocytes induced autophagy mainly through suppressing the expression of p62, thereby contributing to OA progression.

Physiological response and microRNA expression profiles in head kidney of genetically improved farmed tilapia (GIFT, Oreochromis niloticus) exposed to acute cold stress

Cold stress has a serious impact on the overwintering survival and yield of genetically improved farmed tilapia (GIFT, Oreochromis niloticus). Understanding the physiological and molecular regulation mechanisms of low-temperature adaptation is necessary to help breed new tolerant strains. The semi-lethal low temperature of juvenile GIFT at 96 h was determined as 9.4 °C. We constructed and sequenced two small RNA libraries from head kidney tissues, one for the control (CO) group and one for the 9.4 °C-stressed (LTS) group, and identified 1736 and 1481 known microRNAs (miRNAs), and 164 and 152 novel miRNAs in the CO and LTS libraries, respectively. We verify the expression of nine up-regulated miRNAs and eight down-regulation miRNAs by qRT-PCR, and found their expression patterns were consistent with the sequencing results. We found that cold stress may have produced dysregulation of free radical and lipid metabolism, decreased superoxide dismutase activity, reduced respiratory burst and phagocytic activity of macrophages, increased malondialdehyde content, and adversely affected the physiological adaptation of GIFT, eventually leading to death. This study revealed interactions among miRNAs and signal regulated pathways in GIFT under cold stress that may help to understand the pathways involved in cold resistance.

Small non-coding RNAs-based bone regulation and targeting therapeutic strategies

Small non-coding RNAs, which are 20-25 nucleotide ribonucleic acids, have emerged as an important transformation in the biological evolution over almost three decades. microRNAs (miRNAs) and short interfering RNAs (siRNAs) are two significant categories of the small RNAs that exert important effects on bone endocrinology and skeletology. Therefore, clarifying the expression and function of these important molecules in bone endocrine physiology and pathology is of great significance for improving their potential therapeutic value for metabolism-associated bone diseases. In the present review, we highlight the recent advances made in understanding the function and molecular mechanism of these small non-coding RNAs in bone metabolism, especially their potentially therapeutic values in bone-related diseases.

Long Non-Coding RNA MALAT1 Interacts With miR-204 to Modulate Human Hilar Cholangiocarcinoma Proliferation, Migration, and Invasion by Targeting CXCR4

Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is involved in the development and progression of many types of tumors. An aberrant expression of MALAT1 was observed in many kinds of cancers. However, the exact effects and molecular mechanisms of MALAT1 in human hilar cholangiocarcinoma (HCCA) progression are still unknown. Here, we investigated the role of MALAT1 in human HCCA cell lines and clinical tumor samples in order to determine the function of this lncRNA. In our research, lncRNA-MALAT1 was specifically upregulated in HCCA tissues and cell lines, and was associated with pathological T stage, a larger tumor size, and perineural invasion. Knockdown of MALAT1 inhibited the proliferation, migration, and invasion of human HCCA cell. In addition, chemokine receptor-4 (CXCR4) was involved in MALAT1 induced human HCCA growth, migration, and invasion. By using online tools and a series of mechanistic analysis, we also demonstrated that miR-204-dependent CXCR4 regulation was required in MALAT1 modulating HCCA cell growth, migration and invasion. Taken together, our data indicated that MALAT1 might play an oncogenic role in HCCA through miR-204-dependent CXCR4 regulation, and could be regarded as a therapeutic target in HCCA. J. Cell. Biochem. 118: 3643-3653, 2017. © 2017 Wiley Periodicals, Inc.

Osteoarthritis year in review 2016: genetics, genomics and epigenetics

The purpose of this narrative review is to provide an overview of last year's publications in the field of genetics, genomics and epigenetics in the osteoarthritis (OA) field. Major themes arising from a Pubmed search on (epi)genetics in OA were identified. In addition, general developments in the fast evolving field of (epi)genetics are reviewed and relevance for the OA field is summarized. In the last 5 years, a number of genome-wide association studies have identified a modest number of genetic loci associated to OA. Continued functional research into these DNA variants is showing putative biological mechanisms underlying these associations. Over the last year, no additional large genome-wide association studies were published, but there clearly remains much to be discovered in the OA genetic field. A lot of research has been done into the epigenetics of OA over the last year. Several genome-wide screens examining the methylome of osteoarthritic cartilage were done. Pathway analysis confirmed deregulation of developmental and extracellular pathways in OA cartilage. Over the last year many microRNAs (miRNAs) have been identified that potentially play important roles in cartilage homeostasis and/or OA process. Continued research will learn whether these identified miRNAs are truly causal and can be used in clinical applications. Many of the epigenetic findings need further confirmation, but they highlight potential novel pathways involved in cartilage biology and OA.

Exosomes derived from miR-140-5p-overexpressing human synovial mesenchymal stem cells enhance cartilage tissue regeneration and prevent osteoarthritis of the knee in a rat model

OBJECTIVES

Osteoarthritis (OA) is the most common joint disease throughout the world. Exosomes derived from miR-140-5p-overexpressing synovial mesenchymal stem cells (SMSC-140s) may be effective in treating OA. We hypothesized that exosomes derived from SMSC-140 (SMSC-140-Exos) would enhance the proliferation and migration abilities of articular chondrocytes (ACs) without harming extracellular matrix (ECM) secretion.

METHODS

SMSCs were transfected with or without miR-140-5p. Exosomes derived from SMSCs or SMSC-140s (SMSC-Exos or SMSC-140-Exos) were isolated and identified. Proliferation, migration and ECM secretion were measured in vitro and compared between groups. The mechanism involving alternative Wnt signalling and activation of Yes-associated protein (YAP) was investigated using lentivirus, oligonucleotides or chemical drugs. The preventative effect of exosomes in vivo was measured using Safranin-O and Fast green staining and immunohistochemical staining.

RESULTS

Wnt5a and Wnt5b carried by exosomes activated YAP via the alternative Wnt signalling pathway and enhanced proliferation and migration of chondrocytes with the side-effect of significantly decreasing ECM secretion. Highly-expressed miR-140-5p blocked this side-effect via RalA. SMSC-140-Exos enhanced the proliferation and migration of ACs without damaging ECM secretion in vitro, while in vivo, SMSC-140-Exos successfully prevented OA in a rat model.

CONCLUSIONS

These findings highlight the promising potential of SMSC-140-Exos in preventing OA. We first found a potential source of exosomes and studied their merits and shortcomings. Based on our understanding of the molecular mechanism, we overcame the shortcomings by modifying the exosomes. Such exosomes derived from modified cells hold potential as future therapeutic strategies.

miRNAs Related to Skeletal Diseases

miRNAs as non-coding, short, double-stranded RNA segments are important for cellular biological functions, such as proliferation, differentiation, and apoptosis. miRNAs mainly contribute to the inhibition of important protein translations through their cleavage or direct repression of target messenger RNAs expressions. In the last decade, miRNAs got in the focus of interest with new publications on miRNAs in the context of different diseases. For many types of cancer or myocardial damage, typical signatures of local or systemically circulating miRNAs have already been described. However, little is known about miRNA expressions and their molecular effect in skeletal diseases. An overview of published studies reporting miRNAs detection linked with skeletal diseases was conducted. All regulated miRNAs were summarized and their molecular interactions were illustrated. This review summarizes the involvement and interaction of miRNAs in different skeletal diseases. Thereby, 59 miRNAs were described to be deregulated in tissue, cells, or in the circulation of osteoarthritis (OA), 23 miRNAs deregulated in osteoporosis, and 107 miRNAs deregulated in osteosarcoma (OS). The molecular influences of miRNAs regarding OA, osteoporosis, and OS were illustrated. Specific miRNA signatures for skeletal diseases are described in the literature. Some overlapped, but also unique ones for each disease exist. These miRNAs may present useful targets for the development of new therapeutic approaches and are candidates for diagnostic evaluations.