WITHDRAWN: MicroRNA-107 regulates autophagy and apoptosis of osteoarthritis chondrocytes by targeting TRAF3

CircRNA SEC24A promotes osteoarthritis through miR-107-5p/CASP3 axis

Background

Osteoarthritis (OA) is the most frequently diagnosed chronic joint disease. CircSEC24A is significantly elevated in OA chondrocytes upon IL-1β stimulation. However, its biological function in OA is still not fully understood.

Methods

The circRNAs-miRNA-mRNA network was predicted by bioinformatics analysis. An in vitro OA chondrocytes model was established by IL-1β stimulation. The expression of circSEC24A, miR-107-5p, CASP3, apoptosis-related molecules and extracellular matrix (ECM) components were detected by Western blot and qRT-PCR. MTT assay and Annexin V/PI staining were employed to monitor cell viability and apoptosis, respectively. The interaction between circSEC24A and miR-107-5p, as well as the binding between miR-107-5p and CASP3 3' UTR were detected by luciferase reporter and RIP assays. Cytokine secretion was monitored by ELISA assay. The role of circSEC24A was also explored in anterior cruciate ligament transection (ACLT) rat models.

Results

CircSEC24A and CASP3 were increased, but miR-107-5p was decreased in rat OA cartilage tissues and OA chondrocytes. CircSEC24A acted as a sponge of miR-107-5p. Knockdown of circSEC24A promoted chondrocyte proliferation, but suppressed chondrocyte apoptosis, ECM degradation and inflammation via sponging miR-107-5p. CASP3 was identified as a miR-107-5p target gene. MiR-107-5p mimics protected against OA progression via targeting CASP3. Silencing of circSEC24A alleviated OA progression in ACLT model.

Conclusion

CircSEC24A promotes OA progression through miR-107-5p/CASP3 axis.

Enhancing protein production and growth in chinese hamster ovary cells through miR-107 overexpression

Chinese Hamster Ovary (CHO) cells are widely employed as host cells for biopharmaceutical production. The manufacturing of biopharmaceuticals poses several challenges, including restricted growth potential and inadequate productivity of the host cells. MicroRNAs play a crucial role in regulating gene expression and are considered highly promising tools for cell engineering to enhance protein production. Our study aimed to evaluate the effects of miR-107, which is recognized as an onco-miR, on erythropoietin-producing CHO cells (CHO-hEPO). To assess the impact of miR-107 on CHO cells, a DNA plasmid containing miR-107 was introduced to CHO-hEPO cells through transfection. Cell proliferation and viability were assessed using the trypan blue dye exclusion method. Cell cycle analysis was conducted by utilizing propidium iodide (PI) staining. The quantification of EPO was determined using an immunoassay test. Moreover, the impact of miR-107 on the expression of downstream target genes was evaluated using qRT-PCR. Our findings highlight and underscore the substantial impact of transient miR-107 overexpression, which led to a remarkable 2.7-fold increase in EPO titers and a significant 1.6-fold increase in the specific productivity of CHO cells (p < 0.01). Furthermore, this intervention resulted in significant enhancements in cell viability and growth rate (p < 0.05). Intriguingly, the overexpression of miR‑107 was linked to the downregulation of LATS2, PTEN, and TSC1 genes while concurrently driving upregulation in transcript levels of MYC, YAP, mTOR, and S6K genes within transgenic CHO cells. In conclusion, this study collectively underscores the feasibility of utilizing cancer-associated miRNAs as a powerful tool for CHO cell engineering. However, more in-depth exploration is warranted to unravel the precise molecular intricacies of miR-107's effects in the context of CHO cells.

Regulatory mechanisms of autophagy-related ncRNAs in bone metabolic diseases

Bone metabolic diseases have been tormented and are plaguing people worldwide due to the lack of effective and thorough medical interventions and the poor understanding of their pathogenesis. Non-coding RNAs (ncRNAs) are heterogeneous transcripts that cannot encode the proteins but can affect the expressions of other genes. Autophagy is a fundamental mechanism for keeping cell viability, recycling cellular contents through the lysosomal pathway, and maintaining the homeostasis of the intracellular environment. There is growing evidence that ncRNAs, autophagy, and crosstalk between ncRNAs and autophagy play complex roles in progression of metabolic bone disease. This review investigated the complex mechanisms by which ncRNAs, mainly micro RNAs (miRNAs), long noncoding RNAs (lncRNAs), and circular RNAs (circRNAs), regulate autophagic pathway to assist in treating bone metabolism disorders. It aimed at identifying the autophagy role in bone metabolism disorders and understanding the role, potential, and challenges of crosstalk between ncRNAs and autophagy for bone metabolism disorders treatment.

Epigenetic modification and exosome effects on autophagy in osteoarthritis

Osteoarthritis (OA) is a degenerative disease that leads to joint pain and stiffness and is one of the leading causes of disability and pain worldwide. Autophagy is a highly conserved self-degradation process, and its abnormal function is closely related to human diseases, including OA. Abnormal autophagy regulates cell aging, matrix metalloproteinase metabolism, and reactive oxygen metabolism, which are key in the occurrence and development of OA. There is evidence that drugs directly or indirectly targeting autophagy significantly hinder the progress of OA. In addition, the occurrence and development of autophagy in OA are regulated by many factors, including epigenetic modification, exosomes, crucial autophagy molecules, and signaling pathway regulation. Autophagy, as a new therapeutic target for OA, has widely influenced the pathological mechanism of OA. However, determining how autophagy affects OA pathology and its use in the treatment and diagnosis of targets still need further research.

Advances in understanding effects of miRNAs on apoptosis, autophagy, and pyroptosis in knee osteoarthritis

MicroRNAs (miRNAs) are a class of endogenous small non-coding RNAs. MicroRNAs-mediated signaling pathways play a critical regulatory role in inducing apoptosis, autophagy, and pyroptosis in developing knee osteoarthritis (KOA). Given this, we searched databases, such as PubMed, using keywords including "miRNA," "knee osteoarthritis," "apoptosis," "autophagy," "pyroptosis", and their combinations. Through an extensive literature review, we conclude that miRNAs can be modulated through various signaling pathways, such as Wnt/β-catenin, TGF-β, PI3K/AKT/mTOR, and NLRP3/Caspase-1, to regulate apoptosis, autophagy, and pyroptosis in KOA. Furthermore, we note that P2X7R and HMGB1 may be crucial regulatory molecules involved in the interconnected regulation of apoptosis, autophagy, and pyroptosis in KOA. Additionally, we describe that miR-140-5p and miR-107 can modulate the advancement of KOA chondrocytes by targeting distinct molecules involved in apoptosis, autophagy, and pyroptosis, respectively. Therefore, we conclude that miRNAs may be potential biomarkers and therapeutic targets for the early prediction, diagnosis, and effective therapeutic approaches of KOA.

MicroRNA Signatures in Cartilage Ageing and Osteoarthritis

Osteoarthritis is the most common degenerative joint disorder. MicroRNAs are gene expression regulators that act post-transcriptionally to control tissue homeostasis. Microarray analysis was undertaken in osteoarthritic intact, lesioned and young intact cartilage. Principal component analysis showed that young intact cartilage samples were clustered together; osteoarthritic samples had a wider distribution; and osteoarthritic intact samples were separated into two subgroups, osteoarthritic-Intact-1 and osteoarthritic-Intact-2. We identified 318 differentially expressed microRNAs between young intact and osteoarthritic lesioned cartilage, 477 between young intact and osteoarthritic-Intact-1 cartilage and 332 between young intact and osteoarthritic-Intact-2 cartilage samples. For a selected list of differentially expressed microRNAs, results were verified in additional cartilage samples using qPCR. Of the validated DE microRNAs, four-miR-107, miR-143-3p, miR-361-5p and miR-379-5p-were selected for further experiments in human primary chondrocytes treated with IL-1β. Expression of these microRNAs decreased in human primary chondrocytes treated with IL-1β. For miR-107 and miR-143-3p, gain- and loss-of-function approaches were undertaken and associated target genes and molecular pathways were investigated using qPCR and mass spectrometry proteomics. Analyses showed that WNT4 and IHH, predicted targets of miR-107, had increased expression in osteoarthritic cartilage compared to young intact cartilage and in primary chondrocytes treated with miR-107 inhibitor, and decreased expression in primary chondrocytes treated with miR-107 mimic, suggesting a role of miR-107 in chondrocyte survival and proliferation. In addition, we identified an association between miR-143-3p and EIF2 signalling and cell survival. Our work supports the role of miR-107 and miR-143-3p in important chondrocyte mechanisms regulating proliferation, hypertrophy and protein translation.

Osteoarthritis: pathogenic signaling pathways and therapeutic targets

Osteoarthritis (OA) is a chronic degenerative joint disorder that leads to disability and affects more than 500 million population worldwide. OA was believed to be caused by the wearing and tearing of articular cartilage, but it is now more commonly referred to as a chronic whole-joint disorder that is initiated with biochemical and cellular alterations in the synovial joint tissues, which leads to the histological and structural changes of the joint and ends up with the whole tissue dysfunction. Currently, there is no cure for OA, partly due to a lack of comprehensive understanding of the pathological mechanism of the initiation and progression of the disease. Therefore, a better understanding of pathological signaling pathways and key molecules involved in OA pathogenesis is crucial for therapeutic target design and drug development. In this review, we first summarize the epidemiology of OA, including its prevalence, incidence and burdens, and OA risk factors. We then focus on the roles and regulation of the pathological signaling pathways, such as Wnt/β-catenin, NF-κB, focal adhesion, HIFs, TGFβ/ΒΜP and FGF signaling pathways, and key regulators AMPK, mTOR, and RUNX2 in the onset and development of OA. In addition, the roles of factors associated with OA, including MMPs, ADAMTS/ADAMs, and PRG4, are discussed in detail. Finally, we provide updates on the current clinical therapies and clinical trials of biological treatments and drugs for OA. Research advances in basic knowledge of articular cartilage biology and OA pathogenesis will have a significant impact and translational value in developing OA therapeutic strategies.

Autophagy in the pathogenesis and therapeutic potential of post-traumatic osteoarthritis

Autophagy, as a fundamental mechanism for cellular homeostasis, is generally involved in the occurrence and progression of various diseases. Osteoarthritis (OA) is the most common musculoskeletal disease that often leads to pain, disability and economic loss in patients. Post-traumatic OA (PTOA) is a subtype of OA, accounting for >12% of the overall burden of OA. PTOA is often caused by joint injuries including anterior cruciate ligament rupture, meniscus tear and intra-articular fracture. Although a variety of methods have been developed to treat acute joint injury, the current measures have limited success in effectively reducing the incidence and delaying the progression of PTOA. Therefore, the pathogenesis and intervention strategy of PTOA need further study. In the past decade, the roles and mechanisms of autophagy in PTOA have aroused great interest in the field. It was revealed that autophagy could maintain the homeostasis of chondrocytes, reduce joint inflammatory level, prevent chondrocyte death and matrix degradation, which accordingly improved joint symptoms and delayed the progression of PTOA. Moreover, many strategies that target PTOA have been revealed to promote autophagy. In this review,  we summarize the roles and mechanisms of autophagy in PTOA and the current strategies for PTOA treatment that depend on autophagy regulation, which may be beneficial for PTOA patients in the future.

MicroRNAs and long non-coding RNAs in cartilage homeostasis and osteoarthritis

During the last decade, osteoarthritis (OA) has become one of the most prevalent musculoskeletal diseases worldwide. OA is characterized by progressive loss of articular cartilage, abnormal remodeling of subchondral bone, hyperplasia of synovial cells, and growth of osteophytes, which lead to chronic pain and disability. The pathological mechanisms underlying OA initiation and progression are still poorly understood. Non-coding RNAs (ncRNAs) constitute a large portion of the transcriptome that do not encode proteins but function in numerous biological processes. Cumulating evidence has revealed a strong association between the changes in expression levels of ncRNA and the disease progression of OA. Moreover, loss- and gain-of-function studies utilizing transgenic animal models have demonstrated that ncRNAs exert vital functions in regulating cartilage homeostasis, degeneration, and regeneration, and changes in ncRNA expression can promote or decelerate the progression of OA through distinct molecular mechanisms. Recent studies highlighted the potential of ncRNAs to serve as diagnostic biomarkers, prognostic indicators, and therapeutic targets for OA. MiRNAs and lncRNAs are two major classes of ncRNAs that have been the most widely studied in cartilage tissues. In this review, we focused on miRNAs and lncRNAs and provided a comprehensive understanding of their functional roles as well as molecular mechanisms in cartilage homeostasis and OA pathogenesis.

The Role of Autophagy in Osteoarthritic Cartilage

Osteoarthritis (OA) is one of the most common diseases leading to physical disability, with age being the main risk factor, and degeneration of articular cartilage is the main focus for the pathogenesis of OA. Autophagy is a crucial intracellular homeostasis system recycling flawed macromolecules and cellular organelles to sustain the metabolism of cells. Growing evidences have revealed that autophagy is chondroprotective by regulating apoptosis and repairing the function of damaged chondrocytes. Then, OA is related to autophagy depending on different stages and models. In this review, we discuss the character of autophagy in OA and the process of the autophagy pathway, which can be modulated by some drugs, key molecules and non-coding RNAs (microRNAs, long non-coding RNAs and circular RNAs). More in-depth investigations of autophagy are needed to find therapeutic targets or diagnostic biomarkers through in vitro and in vivo situations, making autophagy a more effective way for OA treatment in the future. The aim of this review is to introduce the concept of autophagy and make readers realize its impact on OA. The database we searched in is PubMed and we used the keywords listed below to find appropriate article resources.

Circular RNA MELK Promotes Chondrocyte Apoptosis and Inhibits Autophagy in Osteoarthritis by Regulating MYD88/NF-κB Signaling Axis through MicroRNA-497-5p

Osteoarthritis (OA) is a rheumatic disease and its pathogenesis involves the dysregulation of noncoding RNAs. Therefore, the regulatory mechanism of circular RNA MELK (circMELK) was specified in this work. OA human cartilage tissue was collected, and circMELK, miR-497-5p, and myeloid differentiation factor 88 (MYD88) expression were examined. Human chondrocytes were stimulated with interleukin- (IL-) 1β and interfered with vectors altering circMELK, miR-497-5p, and MyD88 expression to observe their effects on cell viability, cell cycle and apoptosis, autophagy, and inflammation. The binding relationship between RNAs was verified. The data presented that OA cartilage tissues presented raised circMELK and MYD88 and inhibited miR-497-5p expression. IL-1β suppressed cell viability, prevented cell cycle, and induced apoptosis, autophagy, and inflammation of chondrocytes. Functionally, IL-1β-induced changes of chondrocytes could be attenuated by suppressing circMELK or overexpressing miR-497-5p. circMELK acted as a sponge of miR-497-5p while miR-497-5p was a regulator of MYD88. MYD88 restricted the effect of overexpressing miR-497-5p on IL-1β-stimulated chondrocytes. MYD88 triggered nuclear factor-kappaB (NF-κB) pathway activation. Shortly, CircMELK promotes chondrocyte apoptosis and inhibits autophagy in OA by regulating MYD88/NF-κB signaling axis through miR-497-5p. Our study proposes a new molecular mechanism for the development of OA.

Circ-NCX1 inhibits LPS-induced chondrocyte apoptosis by regulating the miR-133a/SIRT1 axis

Osteoarthritis (OA) is a degenerative joint disease, which is characterized by the degeneration of articular cartilage, thickening of subchondral bone, and inflammation of the synovial membrane. In this study, we aimed to investigate the effects and underlying mechanisms of circ-NCX1 in lipopolysaccharide (LPS)-induced injury in SW1353 chondrocytes, an in vitro model of OA. The levels of circ-NCX1, miR-133a, and related apoptotic proteins were determined by RT-qPCR. MTT assay was used to evaluate the cell viability. The apoptosis was determined by flow cytometry, whereas the expression of apoptosis proteins was detected by Western blot. Immunofluorescence was used to detect cleaved caspase-3 expression in cells. Luciferase reporter assay was used to verify the interaction between circ-NCX1 and miR-133a, and between miR-133a and Silent information regulator 2 homolog 1 (Sirt1). The results showed that the overexpression of circ-NCX1 significantly upregulated the chondrocyte viability and proliferation, and alleviated apoptosis in LPS-induced SW1353 cells. Immunofluorescence results showed that the overexpression of circ-NCX1 significantly reduced expression of LPS-stimulated cleaved Caspase-3. The RT-qPCR results showed that the overexpression of circ-NCX1 inhibited mRNA levels of cleaved Caspase-3 and Bax, and promoted mRNA levels of Bcl-2. Luciferase reporter assay showed that circ-NCX1 targeted miR-133a, and miR-133a directly targeted the Sirt1. In addition, overexpression of circ-NCX1 inhibited chondrocyte apoptosis and promoted Akt phosphorylation via the miR-133a/Sirt1 axis in LPS-induced chondrocytes. In conclusion, circ-NCX1 may serve as an important regulator of LPS-induced chondrocyte apoptosis through the miR-133a/Sirt1 axis, and may be involved in the development of OA.

LncRNA LEMD1-AS1 relieves chondrocyte inflammation by targeting miR-944/PGAP1 in osteoarthritis

Osteoarthritis (OA) is a common degenerative disease characterized by reducing articular chondrocytes and destruction of joint matrix, it's detailed pathogenesis remains unclear. Emerging evidences have demonstrated that long non-coding RNAs (lncRNAs) are closely related to the progression of OA. This study aims to explore the expression of long non-coding RNA LEMD1 antisense RNA 1 (LEMD1-AS1) in OA tissues and chondrocytes and investigate the possible mechanisms of LEMD1-AS1 in OA, which will provide a new target for the treatment of OA. In our study, LEMD1-AS1 and post-GPI attachment to protein (PGAP1) were lowly expressed, but miR-944 was highly expressed both in OA tissues and in Lipopolysaccharide (LPS) -treated chondrocytes detected by qRT-PCR. Over-expression of LEMD1-AS1 or down-regulation of miR-944 significantly promoted viability, proliferation and inhibited cell apoptosis, cell cycle arrest and inflammatory responses of chondrocytes treated with LPS by CCK-8, EdU, flow cytometry and an ELISA assay. Over-expression of LEMD1-AS1 or down-regulation of miR-944 remarkably increased the protein levels of PCNA, Ki-67, Cyclin A1, Cyclin B1, Cyclin D2 and Bcl-2, while decreasing the protein levels of p27, Bax, Cleaved-caspase-3 and Cleaved-caspase-9 in chondrocytes treated with LPS. LEMD1-AS1 bound to miR-944 and regulated its expression, and PGAP1 presented as a direct target gene of miR-944, which was confirmed by a dual-luciferase reporter assay. Inhibition of PGAP1 partially restored the effects of LEMD1-AS1/miR-944 on the proliferation, cell apoptosis, cell cycle distribution and inflammatory responses of LPS-treated chondrocytes. To conclude, the LEMD1-AS1/miR-944/PGAP1 axis may be a novel therapeutic candidate to target in OA treatment.

Role of autophagy and transcriptome regulation in acute brain injury

Autophagy is an evolutionarily conserved intracellular system that routes distinct cytoplasmic cargo to lysosomes for degradation and recycling. Accumulating evidence highlight the mechanisms of autophagy, such as clearance of proteins, carbohydrates, lipids and damaged organelles. The critical role of autophagy in selective degradation of the transcriptome is still emerging and could shape the total proteome of the cell, and thus can regulate the homeostasis under stressful conditions. Unregulated autophagy that potentiates secondary brain damage is a key pathological features of acute CNS injuries such as stroke and traumatic brain injury. This review discussed the mutual modulation of autophagy and RNA and its significance in mediating the functional consequences of acute CNS injuries.

A review of non-coding RNA related to NF-κB signaling pathway in the pathogenesis of osteoarthritis

Osteoarthritis (OA), often called as "wear and tear" arthritis, is the most common form of degenerative joint arthritis and is a leading cause of disability. The nuclear factor-kappaB (NF-κB) transcription factor has long been recognized as a disease-contributing factor for OA. More and more evidences show that targeting NF-κB signaling could offer novel potential therapeutic options for OA damage and reduce the risk of potential side-effects. In recent years, it has been shown that non-coding RNAs(ncRNAs) can trigger the expression of an array of genes and widely activate NF-κB signaling pathway, which induces destruction of the articular joint, leading to OA onset and progression. In this review, we discuss the involvement of NF-κB in OA pathogenesis and how ncRNAs attend and affect OA incidence and evolution, offering novel potential therapeutic options for OA treatment.

Genetic biomarkers in osteoarthritis: a quick overview

Osteoarthritis (OA) is a chronic musculoskeletal disease with a polygenic and heterogeneous nature. In addition, when clinical manifestations appear, the evolution of the disease is usually already irreversible. Therefore, the efforts on OA research are focused mainly on the discovery of therapeutic targets and reliable biomarkers that permit the early identification of different OA-related parameters such as diagnosis, prognosis, or phenotype identification. To date, potential candidate protein biomarkers have been associated with different aspects of the disease; however, there is currently no gold standard. In this sense, genomic data could act as complementary biomarkers of diagnosis and prognosis or even help to identify therapeutic targets of the disease. In this review, we will describe the most recent advances in genetic biomarkers in OA over the past three years.

MicroRNA-494-3p prevents liver fibrosis and attenuates hepatic stellate cell activation by inhibiting proliferation and inducing apoptosis through targeting TRAF3

INTRODUCTION AND OBJECTIVES

Alcoholic hepatitis (AH) is characterized by high morbidity and mortality. MicroRNA-494-3p is possibly involved in the regulation of cancers, but its role in AH has been rarely studied.

MATERIALS AND METHODS

AH mice model and primarily cultured mice hepatic stellate cells (HSCs) model were constructed. Levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were analyzed by ELISA. Expressions of miRNAs, HSC activation-related proteins and fibrosis-related protein were analyzed by qRT-PCR and Western blot. Cell counting kit, colony formation and flow cytometry assays were used to detect cell viability, proliferation and apoptosis, respectively. The relationship between TNF receptor-associated factor 3 (TRAF3) and miR-494-3p was predicted and verified by TargetScan and dual-luciferase assay, respectively. Results of the above experiments were verified by rescue experiments using TRAF3.

RESULTS

Liver damage and miRNA expression were observed in AH mice, and AST and ALT levels were increased in serum of AH mice. MiR-494-3p was reduced in AH liver tissues, and it decreased the levels of α-SMA and fibrosis-related proteins. HSCs were isolated, and activating HSCs or upregulating miR-494-3p had a regulatory effect on the levels of miR-494-3p, HSC activation-related proteins and fibrosis-related proteins as well as cell viability, proliferation and apoptosis. In addition, miR-494-3p targeted TRAF3 and inhibited TRAF3 expression, while overexpressed TRAF3 promoted TRAF3 expression and rescued the regulatory effect of miR-494-3p on the levels of related proteins as well as cell viability, proliferation and apoptosis.

CONCLUSIONS

This study provided a novel mechanistic comprehension of the anti-fibrotic effect of miR-494-3p.

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.

Recent Advances in Pharmacological Intervention of Osteoarthritis: A Biological Aspect

Osteoarthritis (OA) is a degenerative joint disease in the musculoskeletal system with a relatively high incidence and disability rate in the elderly. It is characterized by the degradation of articular cartilage, inflammation of the synovial membrane, and abnormal structure in the periarticular and subchondral bones. Although progress has been made in uncovering the molecular mechanism, the etiology of OA is still complicated and unclear. Nevertheless, there is no treatment method that can effectively prevent or reverse the deterioration of cartilage and bone structure. In recent years, in the field of pharmacology, research focus has shifted to disease prevention and early treatment rather than disease modification in OA. Biologic agents become more and more attractive as their direct or indirect intervention effects on the initiation or development of OA. In this review, we will discuss a wide spectrum of biologic agents ranging from DNA, noncoding RNA, exosome, platelet-rich plasma (PRP), to protein. We searched for key words such as OA, DNA, gene, RNA, exosome, PRP, protein, and so on. From the pharmacological aspect, stem cell therapy is a very special technique, which is not included in this review. The literatures ranging from January 2016 to August 2021 were included and summarized. In this review, we aim to help readers have a complete and precise understanding of the current pharmacological research progress in the intervention of OA from the biological aspect and provide an indication for the future translational studies.

Recombinant platelet-derived growth factor-BB alleviates osteoarthritis in a rat model by decreasing chondrocyte apoptosis in vitro and in vivo

Osteoarthritis (OA) is a common joint disease that mainly affects the diarthrodial joints. Treatments for OA include non‐pharmacological interventions, topical and oral therapies, intra‐articular therapies and joint surgery. However, all the treatments mentioned above mainly aim to control the symptoms instead of improving or reversing the joint condition. In this research, we observed the effect of recombinant platelet‐derived growth factor (PDGF)‐BB on OA in a monosodium iodoacetate (MIA)–induced rat model and revealed the possible mechanisms. In vitro, the level of inflammation in the chondrocytes was gradually alleviated, and the apoptosis rate was gradually decreased by PDGF‐BB at increasing concentrations. The levels of p‐p38, Bax and caspase‐3 decreased, and the level of p‐Erk increased with increasing PDGF‐BB concentration. In vivo, PDGF‐BB could significantly reverse chondrocyte and matrix loss. Furthermore, high concentrations of PDGF‐BB could alleviate cartilage hyperplasia to remodel the tissue. The level of collagen II was up‐regulated, and the levels of collagen X and apoptosis were down‐regulated by increasing concentrations of PDGF‐BB. In conclusion, recombinant PDGF‐BB alleviated OA by down‐regulating caspase‐3‐dependent apoptosis. The effects of PDGF‐BB on OA mainly include inhibiting chondrocyte loss, reducing cartilage hyperplasia and osteophyte formation, and regulating collagen anabolism.

Knockdown of long noncoding RNA HOTAIR inhibits osteoarthritis chondrocyte injury by miR-107/CXCL12 axis

BACKGROUND

Osteoarthritis (OA) is a joint disease characterized via destruction of cartilage. Chondrocyte damage is associated with cartilage destruction during OA. Long noncoding RNAs (lncRNAs) are implicated in the regulation of chondrocyte damage in OA progression. This study aims to investigate the role and underlying mechanism of lncRNA homeobox antisense intergenic RNA (HOTAIR) in OA chondrocyte injury.

METHODS

Twenty-three OA patients and healthy controls without OA were recruited. Chondrocytes were isolated from OA cartilage tissues. HOTAIR, microRNA-107 (miR-107) and C-X-C motif chemokine ligand 12 (CXCL12) levels were measured by quantitative real-time polymerase chain reaction and western blot. Cell proliferation, apoptosis and extracellular matrix (ECM) degradation were measured using cell counting kit-8, flow cytometry and western blot. The target interaction was explored by bioinformatics, luciferase reporter and RNA immunoprecipitation assays.

RESULTS

HOTAIR expression was enhanced, and miR-107 level was reduced in OA cartilage samples. HOTAIR overexpression inhibited cell proliferation, but induced cell apoptosis and ECM degradation in chondrocytes. HOTAIR knockdown caused an opposite effect. MiR-107 was sponged and inhibited via HOTAIR, and knockdown of miR-107 mitigated the effect of HOTAIR silence on chondrocyte injury. CXCL12 was targeted by miR-107. CXCL12 overexpression attenuated the roles of miR-107 overexpression or HOTAIR knockdown in the proliferation, apoptosis and ECM degradation. CXCL12 expression was decreased by HOTAIR silence, and restored by knockdown of miR-107.

CONCLUSION

HOTAIR knockdown promoted chondrocyte proliferation, but inhibited cell apoptosis and ECM degradation in OA chondrocytes by regulating the miR-107/CXCL12 axis.

Effects of Atrial Fibrillation-Derived Exosome Delivery of miR-107 to Human Umbilical Vein Endothelial Cells

The aim of this study was to explore the effects of atrial fibrillation (AF)-derived exosome delivery of miR-107 to human umbilical vein endothelial cells (HUVECs) and its related mechanisms. Exosomes were isolated from the plasma of patients with AF and healthy controls, followed by characterization. The expression levels of miR-320d, miR-103a-3p, and miR-107 were measured using real-time quantitative PCR (RT-qPCR). The dual-luciferase reporter gene was used to verify the downstream target of miR-107. Afterward, HUVECs were treated with AF-derived exosomes or transfected with miR-107 mimics. After cell culture, Cell Counting Kit-8, Transwell, and flow cytometry were used to determine cell viability, migration, and apoptosis and cell cycle phase. Finally, RT-qPCR was performed to examine the expression of related genes. NanoSight, transmission electron microscopy, and western blotting showed that exosomes were successfully isolated, and that AF-derived exosomes could be taken up by HUVECs. The expression of miR-107 was significantly higher in AF-derived exosomes than in normal exosomes (p < 0.05). USP14 was shown to be the direct target of miR-107. In addition, miR-107 mimics and AF-derived exosomes significantly suppressed cell viability and migration (p < 0.05) and enhanced cell apoptosis; they also increased G0/G1-phase cells and reduced S-phase cells. RT-qPCR showed that exosomal miR-107 overexpression significantly downregulated the expression of USP14 and Bcl2 (p < 0.05), whereas it markedly upregulated the expression of ERK2, FAK, and Bax (p < 0.05). AF-derived exosomes can deliver miR-107 to HUVECs, and exosomal miR-107 may regulate cell viability, migration, and apoptosis and cell cycle progression by mediating the miR-107/USP14 pathway.

Data Integration Reveals the Potential Biomarkers of Circulating MicroRNAs in Osteoarthritis

The abnormal expression of circulating miRNAs (c-miRNAs) has become an emerging field in the development of miRNAs-based diagnostic and therapeutic tools for human diseases, including osteoarthritis (OA). OA is the most common form of arthritis leading to disability and a major socioeconomic burden. The abnormal expression of miRNAs plays important roles in the pathogenesis of OA. Unraveling the role of miRNAs in the pathogenesis of OA will throw light on the potential for the development of miRNAs-based diagnostic and therapeutic tools for OA. This article reviews and highlights recent advances in the study of miRNAs in OA, with specific demonstration of the functions of miRNA, especially c-miRNA, in OA pathogenesis as well as its potential implication in the treatment of OA. Based on a systematic literature search using online databases, we figured out the following main points: (1) the integrative systematic review of c-mRNAs and its target genes related to OA pathogenesis; (2) the potential use of c-miRNAs for OA diagnosis purposes as potential biomarkers; and (3) for therapeutic purposes, and we also highlight certain remedies that regulate microRNA expression based on its target genes.

Osteoarthritis year in review: genetics, genomics, epigenetics

OBJECTIVE

In this review, we have highlighted advances in genetics, genomics and epigenetics in the field of osteoarthritis (OA) over the past year.

METHODS

A literature search was performed using PubMed and the criteria: "osteoarthritis" and one of the following terms "genetic(s), genomic(s), epigenetic(s), epigenomic(s), noncoding RNA, microRNA, long noncoding RNA, lncRNA, circular RNA, RNA sequencing, single cell sequencing, or DNA methylation between April 1, 2019 and April 30, 2020.

RESULTS

We identified 653 unique publications, many studies spanned multiple search terms. We summarized advances relating to evolutionary genetics, pain, ethnicity specific risk factors, functional studies of gene variants, and interactions between coding and non-coding RNAs in OA pathogenesis.

CONCLUSIONS

Studies have identified variants contributing to OA susceptibility, candidate biomarkers for diagnosis and prognosis, as well as promising therapeutic candidates. Validation in multiple cohorts, multi-omics strategies, and machine learning aided computational analyses have all contributed to the strength of published literature. Open access data-sets, greater sample sizes to capture broader populations and understanding disease mechanisms by investigating the interactions between multiple tissue types will further aid in progress towards understanding and curing OA.

miR-107 affects cartilage matrix degradation in the pathogenesis of knee osteoarthritis by regulating caspase-1

Background

Knee osteoarthritis (KOA) seriously affects the quality of life of KOA patients. This study aimed to investigate whether miR-107 could regulate KOA through pyroptosis to affect collagen protein secreted by chondrocytes through IL-1β.

Methods

The proliferation of chondrocytes was detected by CCK-8 assay. RT-qPCR analysis was used to identify miR-107 expression and transfection effects. The expression of Col II, IL-1β, IL-18, and MMP13 in supernatant of chondrocytes or chondrocytes was detected by ELISA assay and western blot analysis. The pyroptosis of chondrocytes was analyzed by TUNEL assay and the expression of pyroptosis-related proteins was analyzed by western blot. Luciferase reporter assay confirmed the relation of miR-107 to caspase-1.

Results

The proliferation of chondrocytes was decreased after LPS induction and further decreased by treatment of ATP. Single LPS treatment for chondrocytes downregulated the Col II expression while upregulated the expression of IL-1β, IL-18, and MMP-13, which was further changed by ATP treatment. miR-107 expression was decreased in chondrocytes induced by LPS and further decreased in chondrocytes induced by LPS and ATP. In addition, miR-107 overexpression increased the proliferation and decreased the pyroptosis of chondrocytes induced by LPS and ATP. miR-107 overexpression upregulated the Col II expression while down-regulated the expression of IL-1β, IL-18, and MMP-13 in supernatant of chondrocytes or chondrocytes induced by LPS and ATP. miR-107 overexpression down-regulated the expression of caspase-1, c-caspase-1, GSDMD-N, and TLR4 in chondrocytes induced by LPS and ATP. Furthermore, miR-107 directly targeted caspase-1.

Conclusions

miR-107 can protect against KOA by downregulating caspase-1 to decrease pyroptosis, thereby promoting collagen protein secreted by chondrocytes by down-regulating IL-1β.

Engineered-extracellular vesicles as an optimistic tool for microRNA delivery for osteoarthritis treatment

Worldwide, osteoarthritis (OA) is one of the most common chronic diseases. In OA, profiling gene expression changes occur and cartilage tissue homeostasis is lost. Suggestions for OA treatment include regulation of gene expressions via the use of microRNAs (miRNAs). However, problems exist with the use of miRNAs, the most important of which is the delivery of sufficient amounts of effective miRNAs to save cartilage tissue. The engineering of extracellular vesicles (EVs) with the use of advanced techniques would be an efficient OA treatment. Therefore, we discuss the importance of miRNAs in terms of cartilage tissue regeneration and review recent advances in production of enriched EVs and miRNA delivery by EVs for future clinical applications.

MicroRNA-mediated autophagy regulation in cancer therapy: The role in chemoresistance/chemosensitivity

Chemoresistance has doubled the effort needed to reach an effective treatment for cancer. Now, scientists should consider molecular pathways and mechanisms involved in chemoresistance to overcome cancer. Autophagy is a "self-digestion" mechanism in which potentially toxic and aged organelles and macromolecules are degraded. Increasing evidence has shown that autophagy possesses dual role in cancer cells (onco-suppressor or oncogene). So, it is vital to identify its role in cancer progression and malignancy. MicroRNAs (miRs) are epigenetic factors capable of modulation of autophagy in cancer cells. In the current review, we emphasize on the relationship between miRs and autophagy in cancer chemotherapy. Besides, we discuss upstream mediators of miR/autophagy axis in cancer chemotherapy including long non-coding RNAs, circular RNAs, Nrf2 c-Myc, and HIF-1α. At the final section, we provide a discussion about how anti-tumor compounds affect miR/autophagy axis in ensuring chemosensitivity. These topics are described in this review to show how autophagy inhibition/induction can lead to chemosensitivity/chemoresistance, and miRs are considered as key players in these discussions.

Silencing UHRF1 enhances cell autophagy to prevent articular chondrocytes from apoptosis in osteoarthritis through PI3K/AKT/mTOR signaling pathway

Osteoarthritis (OA) is a common chronic degenerative joint disease, and chondrocyte apoptosis is one of most important pathological changes of OA pathogenesis. Growing studies have shown that Ubiquitin-like with PHD and RING finger domains 1 (UHRF1) is an important epigenetic regulatory factor that regulates cell proliferation and apoptosis of various tumors, but its role in OA remains ill-defined. In the present study, we found that UHRF1 expression was increased in human OA cartilage tissues, compared with normal cartilage tissues. Interleukin-1β (IL-1β), a major inflammatory cytokine that promotes cartilage degradation in OA, was used to stimulate primary human chondrocytes in vitro. The expression of UHRF1 was also enhanced in IL-1β-induced chondrocytes. Moreover, down-regulation of UHRF1 induced an increase on cell proliferation and autophagy, and a decrease on apoptosis of chondrocytes after IL-1β treatment. Further data indicated that silencing UHRF1 attenuated the up-regulation of IL-1β on phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signaling pathway in chondrocytes. Then, an activator of PI3K weakened the effect of UHRF1 silencing on cell proliferation, autophagy, apoptosis of IL-1β-induced chondrocytes, and the cell autophagy special inhibitor 3-methyladenine (3-MA) also showed a same impact on UHRF1, hence suggesting that knockdown of UHRF1 enhances cell autophagy to protect chondrocytes from apoptosis in OA through PI3K/AKT/mTOR signaling pathway. In conclusion, our study suggests that UHRF1 may be a potential regulator of chondrocyte apoptosis in the pathogenesis of OA.

Pathogenesis of Osteoarthritis: Risk Factors, Regulatory Pathways in Chondrocytes, and Experimental Models

As the most common chronic degenerative joint disease, osteoarthritis (OA) is the leading cause of pain and physical disability, affecting millions of people worldwide. Mainly characterized by articular cartilage degradation, osteophyte formation, subchondral bone remodeling, and synovial inflammation, OA is a heterogeneous disease that impacts all component tissues of the articular joint organ. Pathological changes, and thus symptoms, vary from person to person, underscoring the critical need of personalized therapies. However, there has only been limited progress towards the prevention and treatment of OA, and there are no approved effective disease-modifying osteoarthritis drugs (DMOADs). Conventional treatments, including non-steroidal anti-inflammatory drugs (NSAIDs) and physical therapy, are still the major remedies to manage the symptoms until the need for total joint replacement. In this review, we provide an update of the known OA risk factors and relevant mechanisms of action. In addition, given that the lack of biologically relevant models to recapitulate human OA pathogenesis represents one of the major roadblocks in developing DMOADs, we discuss current in vivo and in vitro experimental OA models, with special emphasis on recent development and application potential of human cell-derived microphysiological tissue chip platforms.

TRAF3, a Target of MicroRNA-363-3p, Suppresses Senescence and Regulates the Balance Between Osteoblastic and Adipocytic Differentiation of Rat Bone Marrow-Derived Mesenchymal Stem Cells

Bone marrow-derived mesenchymal stem cells (BMSCs) have the potential to differentiate into osteoblasts or adipocytes, and an imbalance between adipogenesis and osteogenesis causes age-related bone loss. In this study, we determined the influence of tumor necrosis factor receptor-associated factor 3 (TRAF3) on senescence and osteoblastic and adipocytic differentiation of rat BMSCs. TRAF3 expression increased during osteogenic differentiation but decreased during adipocytic differentiation of rat BMSCs, and compared with day 0 cultures, on day 14, the differences were significant. Overexpression of TRAF3 significantly promoted BMSC osteogenic differentiation and suppressed adipogenic differentiation and senescence. Furthermore, Traf3 was determined to be a target gene of miR-363-3p in BMSCs, and TRAF3 expression in BMSCs was reduced by miR-363-3p overexpression. This overexpression attenuated the effects of TRAF3 on BMSC adipogenic differentiation, osteogenic differentiation, and senescence. Taken together, these results uncovered the mechanism by which TRAF3 promotes BMSC osteogenic differentiation and suppresses adipogenic differentiation and senescence, indicating that the miR-363-3p-TRAF3 axis might be a novel therapeutic target for BMSC-based bone tissue engineering in osteoporosis.

Plant homeodomain finger protein 23 inhibits autophagy and promotes apoptosis of chondrocytes in osteoarthritis

BACKGROUND

Plant homeodomain finger protein 23 (PHF23) is a novel autophagy inhibitor gene that has been few studied with respect to orthopedics. This study was to investigate the expression of PHF23 in articular cartilage and synovial tissue, and analyze the relationship between PHF23 and chondrocyte autophagy in osteoarthritis (OA).

METHODS

Immunohistochemical staining and western blot were applied to show the expression of PHF23 in cartilage of different outbridge grades and synovial tissue of patient with OA and healthy control. The normal human chondrocyte pre-treated with rapamycin or 3-methyladenine, treated with interleukin-1β (IL-1β). IL-1β induced expression level of PHF23 and autophagy-related proteins light chain 3B-I (LC3B-I), LC3B-II, and P62, were examined by Western blot. A PHF23 gene knock-down model was constructed with small interfering RNA. Western blot was performed to detect the efficiency of PHF23 and the impact of PHF23 knockout on IL-1β-induced expression of autophagy-related and apoptotic-related proteins in chondrocyte.

RESULTS

The expression of PHF23 was significantly increased in the high-grade cartilage and synovial tissue of patients with OA. The IL-1β-induced expression of PHF23 was gradually enhanced with time. The level of LC3B-II, P62 changed with time. After knockdown of PHF23, the level of autophagy-related proteins increased and apoptotic-related proteins decreased in IL-1β-induced OA-like chondrocytes.

CONCLUSIONS

The expression of PHF23 increased in human OA cartilage and synovium, and was induced by IL-1β through inflammatory stress. PHF23 can suppress autophagy of chondrocytes, and accelerate apoptosis.

Construction for Long Non-Coding RNA (lncRNA)-Associated Competing Endogenous RNA (ceRNA) Network in Human Retinal Detachment (RD) with Proliferative Vitreoretinopathy (PVR)

Background

The aim of this study was to analyze the long non-coding RNA (lncRNA)-associated competing endogenous RNA (ceRNA) network in human retinal tissues following detachment with proliferative vitreoretinopathy (PVR).

Material/Methods

Expression data of 19 human detached retinas with PVR and 19 normal retinas from postmortem donors were downloaded from Gene Expression Omnibust (GEO) database (GSE28133). The R package “limma” was utilized to discriminate the dysregulated lncRNA and mRNA profiles. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses of differentially expressed mRNAs were performed using R packages “Clusterprofiler.” The ceRNA network of dysregulated genes was constructed by using mircode, miRDB, miRTarBase and TargetScan databases, and was visualized by Cytoscape v3.6.1.

Results

A total of 23 lncRNAs and 994 mRNAs were identified significantly expressed between the human detached retinas with PVR and the normal retina tissues, with thresholds of |log₂FoldChange| >1.0 and adjusted P-value <0.05. The constructed ceRNA network (lncRNA-miRNA-mRNA regulatory axis) included 9 PVR-specific lncRNAs, as well as 27 miRNAs and 73 mRNAs.

Conclusions

We demonstrated the differential lncRNA expression profile and constructed a lncRNA-associated ceRNA network in human detached retinas with PVR. This may ferret out an unknown ceRNA regulatory network in human retinal detachment with PVR.

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.

Knockdown of PVT1 inhibits IL-1β-induced injury in chondrocytes by regulating miR-27b-3p/TRAF3 axis

Long noncoding RNA plasmacytoma variant translocation 1 (PVT1) has been identified to implicate in the progression of osteoarthritis (OA). However, the mechanism underlying PVT1 in OA development remains largely unknown. This study aimed to investigate the effect of PVT1 on interleukin-1 beta (IL-1β)-induced injury in chondrocytes and explore potential mechanism. The cartilage tissues from 25 OA patients and normal controls were collected. Human transformed chondrocytes C28/I2 were stimulated by IL-1β. The levels of PVT1, microRNA (miR)-27b-3p, and tumor necrosis factor receptor-associated factor 3 (TRAF3) were detected by quantitative real-time polymerase chain reaction or western blot. IL-1β-induced injury was investigated by cell viability, apoptosis, autophagy and inflammatory response using 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide, flow cytometry, western blot and enzyme linked immunosorbent assay, respectively. The target association between miR-27b-3p and PVT1 or TRAF3 was explored by luciferase reporter, RNA immunoprecipitation and RNA pull-down assays. We found that PVT1 expression was enhanced in OA patients and IL-1β-treated C28/I2 cells. Silence of PVT1 promoted cell viability and autophagy but suppressed apoptosis and inflammatory response in IL-1β-treated C28/I2 cells. miR-27b-3p was confirmed as a target of PVT1 and its deficiency reversed the suppressive effect of PVT1 knockdown on IL-1β-induced injury. TRAF3 was a target of miR-27b-3p and attenuated the effect of miR-27b-3p on IL-1β-induced injury in C28/I2 cells. Moreover, TRAF3 expression was positively regulated by PVT1 via sponging miR-27b-3p. Collectively, knockdown of PVT1 increased cell viability and autophagy but inhibited apoptosis and inflammatory response in chondrocytes treated by IL-1β via up-regulating miR-27b-3p and down-regulating TRAF3.

Long Non-Coding RNA LINC00152 Regulates Cell Proliferation, Migration And Invasion In Esophageal Squamous Cell Carcinoma Via miR-107/Rab10 Axis

Background

Esophageal squamous cell carcinoma (ESCC) is a common  malignant tumor in East Asia. Emerging evidence indicated that long intergenic non-coding RNA 152 (LINC00152) acts as an oncogene in many types of cancers including ESCC. This study aims to identify the biological mechanisms of LINC00152 in ESCC, hinting for new therapeutic target for ESCC patients.

Methods

The levels of LINC00152, microRNA-107 (miR-107) and Ras-related protein Rab-10 (Rab10) were measured in ESCC tissues and cells using qRT-PCR. The protein level of Rab10 was measured by Western blot assay. The putative target of LINC00152 or miR-107 was searched using starBase v2.0 and TargetScan online databases, and dual-luciferase reporter assay was conducted to detect the interaction between miR-107 and LINC00152 or Rab10. The cell viability was monitored by CCK8 assay, and the abilities of migration and invasion were assessed by Transwell assay, respectively. The mice model experiments were constructed to affirm the biological role of LINC00152 in vivo.

Results

LINC00152, Rab10 was significantly upregulated, and miR-107 was strikingly down-regulated in ESCC tissues and cell lines (TE-1 and KYSE30). LINC00152 was verified as a sponge for miR-107, and Rab10 was a direct target of miR-107. LINC00152 depletion decreased cell viability and abilities of migration and invasion by regulating miR-107 in vitro and blocked xenograft tumor growth in vivo. The overexpression of miR-107 reduced cell viability and the abilities of migration and invasion by modulating Rab10. LINC00152 positively regulated Rab10 expression by sponging miR-107.

Conclusion

In this study, we found that LINC00152 modulated Rab10 to promote cell proliferation, migration and invasion in ESCC by sponging miR-107. This new regulatory network may provide a novel therapeutic target for ESCC patients.

Non-Coding RNAs in Cartilage Development: An Updated Review

In the development of the skeleton, the long bones are arising from the process of endochondral ossification (EO) in which cartilage is replaced by bone. This complex process is regulated by various factors including genetic, epigenetic, and environmental elements. It is recognized that DNA methylation, higher-order chromatin structure, and post-translational modifications of histones regulate the EO. With emerging understanding, non-coding RNAs (ncRNAs) have been identified as another mode of EO regulation, which is consist of microRNAs (miRNAs or miRs) and long non-coding RNAs (lncRNAs). There is expanding experimental evidence to unlock the role of ncRNAs in the differentiation of cartilage cells, as well as the pathogenesis of several skeletal disorders including osteoarthritis. Cutting-edge technologies such as epigenome-wide association studies have been employed to reveal disease-specific patterns regarding ncRNAs. This opens a new avenue of our understanding of skeletal cell biology, and may also identify potential epigenetic-based biomarkers. In this review, we provide an updated overview of recent advances in the role of ncRNAs especially focus on miRNA and lncRNA in the development of bone from cartilage, as well as their roles in skeletal pathophysiology.

Modulated Autophagy by MicroRNAs in Osteoarthritis Chondrocytes

Osteoarthritis (OA) is a chronic joint disease characterized by articular cartilage regression. The etiology of OA is diverse, the exact pathogenesis of which remains unclear. Autophagy is a conserved maintenance mechanism in eukaryotic cells. Dysfunction of chondrocyte autophagy is regarded as a crucial pathogenesis of cartilage degradation in OA. MircoRNAs (miRNAs) are a category of small noncoding RNAs, acting as posttranscriptional modulators that regulate biological processes and cell signaling pathways via target genes. A series of miRNAs are involved in the progression of chondrocyte autophagy and are connected with numerous factors and pathways. This article focuses on the mechanisms of chondrocyte autophagy in OA and reviews the role of miRNA in their modulation. Potentially relevant miRNAs are also discussed in order to provide new directions for future research and improve our understanding of the autophagic network of miRNAs.