MicroRNA-377-3p alleviates IL-1β-caused chondrocyte apoptosis and cartilage degradation in osteoarthritis in part by downregulating ITGA6

Modulation of lncRNA NEAT1 overturns the macrophages based immune response in M. tuberculosis infected patients via miR-373 regulation

There is a lack of studies which explore and clarify the interactions that occur between host macrophage and Mycobacterium tuberculosis with regard to microRNA such as LNCNEAT1 and miR-373. The current study determines the mechanisms involved in the control of M. tuberculosis infection by macrophage using LNCNEAT1 and miR-373. The researchers collected different samples from healthy individuals, pulmonary TB patients, and samples like hMDMs cells and H37Rv infected MTB to determine the concentrations of inflammatory factors. The impact of NEAT1 and miR-373 upon macrophages was analyzed in NEAT1-specific siRNA (si-NEAT1), NEAT1 over-expression vector (pcDNA3.1-NEAT1), miR-373 mimic, miR-373 inhibitor (anti-miR-373), and negative control, and macrophages infected with H37Ra. The results inferred that among pulmonary TB patients, NEAT1 got heavily expressed while the expression level of miR-373 was poor. The number of inflammatory factors with pulmonary TB was notably higher. This got further amplified in macrophages after being infected with H37Ra, while no such observations found for miR-373. During post-transfection, low concentration of inflammatory factors was observed while the cells in si-NEAT1 group got proliferated in low volume compared to both pcDNA3.1-NEAT1 group and NEAT1 negative control group. However, the capability of apoptosis was higher compared to the other two groups (p < 0.05). There was an increase observed in inflammatory factors as well as proliferation in anti-miR-373 group compared to miR-373 mimics and miR-373-negative control group while a significant decline was observed in apoptosis. LNCNEAT1 aggravated the number of inflammatory factors in macrophages that got infected with MTB while on the other end, it mitigated both phagocytosis as well as the cellular immunity of macrophages. In addition to this, it enhanced the proliferation of infected cells and inhibited apoptosis via targeted regulation of miR-373, thus resulting in the development of TB.

The role of apoptosis in the pathogenesis of osteoarthritis

PURPOSE

Apoptosis is an important physiological process, making a great difference to development and tissue homeostasis. Osteoarthritis (OA) is a chronic joint disease characterized by degeneration and destruction of articular cartilage and bone hyperplasia. This purpose of this study is to provide an updated review of the role of apoptosis in the pathogenesis of osteoarthritis.

METHODS

A comprehensive review of the literature on osteoarthritis and apoptosis was performed, which mainly focused on the regulatory factors and signaling pathways associated with chondrocyte apoptosis in osteoarthritis and other pathogenic mechanisms involved in chondrocyte apoptosis.

RESULTS

Inflammatory mediators such as reactive oxygen species (ROS), nitric oxide (NO), IL-1β, tumor necrosis factor-α (TNF-α), and Fas are closely related to chondrocyte apoptosis. NF-κB signaling pathway, Wnt signaling pathway, and Notch signaling pathway activate proteins and gene targets that promote or inhibit the progression of osteoarthritis disease, including chondrocyte apoptosis and ECM degradation. Long non-coding RNAs (LncRNAs) and microRNAs (microRNAs) have gradually replaced single and localized research methods and become the main research approaches. In addition, the relationship between cellular senescence, autophagy, and apoptosis was also briefly explained.

CONCLUSION

This review offers a better molecular delineation of apoptotic processes that may help in designing new therapeutic options for OA treatment.

Analysis of RNA Polyadenylation in Healthy and Osteoarthritic Human Articular Cartilage

Polyadenylation (polyA) defines the 3' boundary of a transcript's genetic information. Its position can vary and alternative polyadenylation (APA) transcripts can exist for a gene. This causes variance in 3' regulatory domains and can affect coding sequence if intronic events occur. The distribution of polyA sites on articular chondrocyte transcripts has not been studied so we aimed to define their transcriptome-wide location in age-matched healthy and osteoarthritic knee articular cartilage. Total RNA was isolated from frozen tissue samples and analysed using the QuantSeq-Reverse 3' RNA sequencing approach, where each read runs 3' to 5' from within the polyA tail into the transcript and contains a distinct polyA site. Differential expression of transcripts was significant altered between healthy and osteoarthritic samples with enrichment for functionalities that were strongly associated with joint pathology. Subsequent examination of polyA site data allowed us to define the extent of site usage across all the samples. When comparing healthy and osteoarthritic samples, we found that differential use of polyadenylation sites was modest. However, in the genes affected, there was potential for the APA to have functional relevance. We have characterised the polyadenylation landscape of human knee articular chondrocytes and conclude that osteoarthritis does not elicit a widespread change in their polyadenylation site usage. This finding differentiates knee osteoarthritis from pathologies such as cancer where APA is more commonly observed.

SNHG1 alleviates the oxidative stress and inflammatory response in traumatic brain injury through regulating miR-377-3p/DUSP1 axis

OBJECTIVES

To investigate the role of short nucleolar RNA host gene 1 (SNHG1) in regulating inflammation and brain injury in traumatic brain injury (TBI).

METHODS

The Feeney's free-falling method was used to induce moderate TBI model in mice. Lipopolysaccharide (LPS) was employed to construct the microglia in vitro. Reverse transcription-PCR (RT-PCR) was conducted to monitor expression of SNHG1, microRNAs (miR)-377-3p, oxidative and inflammatory factors. TdT-mediated dUTP nick end labeling and immunohistochemistry were adopted to determine neuronal cell apoptosis. Flow cytometry was conducted to measure apoptosis. Moreover, Bax, Bcl2, Caspase3, dual-specific phosphatase-1 (DUSP1)/mitogen-activated protein kinase/NF-KB were tested by western blot. Furthermore, bioinformatics, dual-luciferase assay and RNA-binding protein immunoprecipitation experiment were implemented to verify the targeting relationship among SNHG1, miR-377-3p and DUSP1.

RESULTS

SNHG1 was knocked down, while miR-377-3p was overexpressed in TBI mice and lipopolysaccharide-induced microglia. Meanwhile, overexpressing SNHG1 reduced neuronal damage and weakened the oxidative stress and inflammation in TBI on matter in vivo or in vitro. Additionally, overexpressing SNHG1 attenuated miR-377-3p-mediated inflammatory factors, oxidative stress and neuronal damage. Moreover, miR-377-3p was the target of SNHG1 and DUSP1.

CONCLUSIONS

This study provides a better understanding of the SNHG1/miR-377-3p/DUSP1 axis in regulating the development of TBI, which is helpful to formulate a treatment plan for TBI.

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.

RNA sequencing-based identification of microRNAs in the antler cartilage of Gansu red deer (Cervus elaphus kansuensis)

Background

The velvet antler is a complex mammalian bone organ with unique biological characteristics, such as regeneration. The rapid growth stage (RGS) is a special period in the regeneration process of velvet antler.

Methods

To elucidate the functions of microRNAs (miRNAs) at the RGS of antler development in Gansu red deer (Cervus elaphus kansuensis), we used RNA sequencing (RNA-seq) to analyze miRNA expression profiles in cartilage tissues of deer antler tips at three different growth stages.

Results

The RNA-seq results revealed 1,073 known and 204 novel miRNAs, including 1,207, 1,242, and 1,204 from 30-, 60-, and 90-d antler cartilage tissues, respectively. To identify key miRNAs controlling rapid antler growth, we predicted target genes of screened 25 differentially expressed miRNAs (DEMs) and specifically expressed miRNAs (SEMs) in 60 d and annotated their functions. The KEGG results revealed that target genes of 25 DEMs and 30 SEMs were highly classified in the "Metabolic pathways", "Pathways in cancer", "Proteoglycans in cancer" and "PI3K-Akt signaling pathway". In addition, a novel miRNA (CM008039.1_315920), highly enriched in "NF-kappa B signaling pathway", may need further study.

Conclusions

The miRNAs identified in our study are potentially important in rapid antler growth. Our findings provide new insights to help elucidate the miRNA-mediated regulatory mechanisms involved during velvet antler development in C. elaphus kansuensis.

Achyranthes bidentata polysaccharides alleviate endoplasmic reticulum stress in osteoarthritis via lncRNA NEAT1/miR-377-3p pathway

Endoplasmic reticulum stress (ERS) has been identified to be an important factor leading to chondrocyte apoptosis in osteoarthritis (OA). Previous studies have confirmed that Achyranthes bidentata polysaccharides (ABPS) can inhibit chondrocyte apoptosis; however, the mechanism of action of ABPS on chondrocyte ERS remains unclear. Thus in this study, we aim to investigate whether ABPS could inhibit OA-associated chondrocyte apoptosis by regulating ERS, especially by observing the relationship between the lncRNA NEAT1 and miR-377-3p, to explore further the protective mechanism of ABPS in OA. In vitro and in vivo experiments showed that ABPS inhibited chondrocyte ERS by regulating the expression of lncRNA NEAT1 and miR-377-3p. Moreover, both lncRNA NEAT1 silencing and miR-377-3p inhibition could attenuate the therapeutic effect of ABPS on ERS. Dual-luciferase results indicated that miR-377-3p targets the lncRNA NEAT1 gene in mouse chondrocytes. Therefore, we concluded that ABPS could inhibit thapsigargin (TG)-induced chondrocyte ERS through the lncRNA NEAT1/miR-377-3p axis.

Long non-coding PRNCR1 regulates the proliferation and apoptosis of synoviocytes in osteoarthritis by sponging miR-377-3p

Background

LncRNA PRNCR1 has been reported to be involved in LPS-induced inflammation, which contributes to osteoarthritis (OA). We predicted that miR-377-3p could bind to PRNCR1.MiR-377-3p can suppress OA development. We therefore analyzed the potential interaction between them in OA.

Methods

Expression of miR-377-3p and PRNCR1 in both OA (n = 40) and control (n = 40) samples were analyzed by RT-qPCR. MiR-377-3p or PRNCR1 were overexpressed in synoviocytes to explore their potential interaction. The subcellular location of PRNCR1 was analyzed by nuclear fractionation assay. The direct interaction between miR-377-3p and PRNCR1 was analyzed by RNA-pull down assay. The proliferation and apoptosis of synoviocytes were analyzed by BrdU and apoptosis assay, respectively.

Results

PRNCR1 was overexpressed in OA, while miR-377-3p was downexpressed in OA. PRNCR1 was detected in the cytoplasm and directly interacted with miR-377-3p. Interestingly, overexpression of PRNCR1 and miR-377-3p showed no regulatory role in each other’s expression. LPS treatment increased PRNCR1 expression and decreased miR-377-3p expression. PRNCR1 overexpression decreased LPS-induced synoviocyte proliferation and increased LPS-induced synoviocyte apoptosis. MiR-377-3p played opposite roles in cell proliferation and apoptosis. Moreover, PRNCR1 suppressed the role of miR-377-3p.

Conclusions

Therefore, PRNCR1 is was detected in cytoplasm and regulates synoviocyte proliferation and apoptosis in OA by sponging miR-377-3p.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-022-03035-2.

Effect of Dietary Polyphenols on Osteoarthritis-Molecular Mechanisms

Osteoarthritis is a common crippling and degenerative disease resulting in irreversible functional changes due to damage of the cartilage and other tissues of the joint. With limited safe and effective pharmaceutical treatments, the demand and use for alternative therapeutic approaches with symptomatic relief for OA patients have increased. Clinical, pre-clinical, and in vitro studies have demonstrated that polyphenols can exert pain-relieving symptoms coupled with increased functional capacity in OA models. This review will highlight studies carried out in the last five years to define the efficacies and underlying mechanisms in polyphenols such as quercetin, resveratrol, curcumin, epigallocatechin-3-gallate, rosmarinic acid, genistein, ginger, berries, silver fir, pine bark, and Boswellia. Most of these studies indicate that polyphenols exhibit their beneficial roles through regulating changes at the biochemical and molecular levels, inducing or inhibiting various signaling pathways related to inflammation and oxidative stress. Polyphenols have also been implicated in modulating microRNA at the posttranscriptional level to counteract OA pathogenesis.

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.

Long Non-coding RNAs in Rheumatology

The last decade has seen an enormous increase in long non-coding RNA (lncRNA) research within rheumatology. LncRNAs are arbitrarily classed as non-protein encoding RNA transcripts that exceed 200 nucleotides in length. These transcripts have tissue and cell specific patterns of expression and are implicated in a variety of biological processes. Unsurprisingly, numerous lncRNAs are dysregulated in rheumatoid conditions, correlating with disease activity and cited as potential biomarkers and targets for therapeutic intervention. In this chapter, following an introduction into each condition, we discuss the lncRNAs involved in rheumatoid arthritis, osteoarthritis and systemic lupus erythematosus. These inflammatory joint conditions share several inflammatory signalling pathways and therefore not surprisingly many commonly dysregulated lncRNAs are shared across these conditions. In the interest of translational research only those lncRNAs which are strongly conserved have been addressed. The lncRNAs discussed here have diverse roles in regulating inflammation, proliferation, migration, invasion and apoptosis. Understanding the molecular basis of lncRNA function in rheumatology will be crucial in fully determining the inflammatory mechanisms that drive these conditions.

Circ-MKLN1/miR-377-3p/CTGF Axis Regulates the TGF-β2-induced Posterior Capsular Opacification in SRA01/04 Cells

OBJECTIVE

Posterior capsular opacification (PCO) is a common postoperative ocular complication after cataract surgery. Little research focused on the regulation of circular RNAs (circRNAs) in PCO. This study was designed to investigate the function of circRNA-muskelin (circ-MKLN1) in PCO.

METHODS

SRA01/04 cells were treated with transforming growth factor (TGF)-β2. Cell viability was analyzed by Cell Counting Kit-8 (CCK-8) assay. Transwell assay was used for cell migration and invasion detection. Cell migration was also measured by wound healing assay. Epithelial-mesenchymal transition (EMT)-related proteins and connective tissue growth factor (CTGF) were quantified using western blot.

RESULTS

Cell viability, migration, invasion and EMT process in SRA01/04 cells were facilitated by TGF-β2. Circ-MKLN1 expression was enhanced in 17 PCO lens samples relative to 19 normal lens samples and TGF-β2-treated SRA01/04 cells contrasted to control cells. Downregulation of circ-MKLN1 inhibited the effects of TGF-β2 on SRA01/04 cells. Circ-MKLN1 targeted miR-377-3p and the regulation of si-circ-MKLN1 for the TGF-β2-induced influences was related to the upregulation of miR-377-3p. CTGF was the target gene for miR-377-3p. CTGF knockdown also abolished the TGF-β2-mediated cell growth, migration and invasion of SRA01/04 cells. The function of miR-377-3p was achieved by reducing the CTGF level. TGF-β2-induced CTGF expression promotion was alleviated by si-circ-MKLN1 through upregulating the expression of miR-377-3p.

CONCLUSION

These results showed that circ-MKLN1 contributed to the progression of PCO in vitro by increasing the CTGF expression via sponging miR-377-3p. Circ-MKLN1 might be important for improving the molecular target therapy in PCO.

LIM mineralization protein-1 inhibits IL-1β-induced human chondrocytes injury by altering the NF-κB and MAPK/JNK pathways

Osteoarthritis (OA) is a common degenerative disease that is associated with the degradation of articular cartilage. Accumulating evidence has confirmed that LIM mineralization protein-1 (LMP-1) is an important agent of bone formation and has been shown to be osteoinductive in various types of disease. However, the underlying mechanisms of LMP-1 in the pathogenesis of OA remain unknown. The present study aimed to evaluate the role and potential mechanism of LMP-1 in IL-1β-stimulated OA chondrocytes. CHON-001 cells were transfected with pcDNA3.1-LMP-1, pcDNA3.1, negative control-small interfering (si)RNA or LMP-1 siRNA for 24 h and then induced by IL-1β for 12 h to establish an OA model in vitro. Cell viability, apoptosis and inflammatory cytokine (IL-6, IL-8 and TNF-α) release were assessed using MTT assay, flow cytometry and ELISA, respectively. The expression levels of LMP-1, cleaved-caspase 3, phosphorylated (p)-p65, p65, p-JNK and JNK were analyzed using reverse transcription-quantitative PCR and western blotting. Overexpression of LMP-1 notably alleviated the IL-1β-induced inflammatory response in CHON-001 cells, as shown by increased cell viability, decreased apoptosis, suppressed expression of cleaved-caspase 3 and a decreased cleaved-caspase 3/caspase 3 ratio. Moreover, IL-1β-induced secretion of IL-6, IL-8 and TNF-α in CHON-001 cells; this was reversed by pcDNA3.1-LMP-1. However, knocking down LMP-1 expression exert opposite effects on the IL-1β-induced inflammatory response in CHON-001 cells, as evidenced by the decreased cell viability, increased apoptosis, enhanced expression of cleaved-caspase 3 and cleaved-caspase 3/caspase 3 ratio and enhanced secretion of IL-6, IL-8 and TNF-α observed. The present data demonstrated that LMP-1 siRNA notably inhibited LMP-1 expression, suppressed cell viability, promoted apoptosis and enhanced cleaved-caspase 3 expression and cleaved-caspase 3/caspase 3 ratio. In addition, LMP-1 siRNA promoted the release of inflammatory factors in CHON-001 cells. It was also found that pcDNA3.1-LMP-1 inhibited p-p65 and p-JNK expression, as well as decreasing the p-p65/p65 and p-JNK/JNK ratio. Nevertheless, there was no significant difference in the mRNA expression levels of p65 and JNK between the groups. Taken together, these findings indicated that overexpression of LMP-1 alleviated IL-1β-induced chondrocytes injury by regulating the NF-κB and MAPK/JNK pathways, suggesting that LMP-1 may be a valuable therapeutic agent for OA treatment.

The Emerging Role of Non-Coding RNAs in Osteoarthritis

Osteoarthritis (OS) is the most frequent degenerative condition in the joints, disabling many adults. Several abnormalities in the articular cartilage, subchondral bone, synovial tissue, and meniscus have been detected in the course of OA. Destruction of articular cartilage, the formation of osteophytes, subchondral sclerosis, and hyperplasia of synovial tissue are hallmarks of OA. More recently, several investigations have underscored the regulatory roles of non-coding RNAs (ncRNAs) in OA development. Different classes of non-coding RNAs, including long ncRNAs (lncRNAs), microRNAs (miRNAs), and circular RNAs (circRNAs), have been reported to affect the development of OA. The expression level of these transcripts has also been used as diagnostic tools in OA. In the present article, we aimed at reporting the role of these transcripts in this process. We need to give a specific angle on the pathology to provide meaningful thoughts on it.

The non-coding RNA interactome in joint health and disease

Non-coding RNAs have distinct regulatory roles in the pathogenesis of joint diseases including osteoarthritis (OA) and rheumatoid arthritis (RA). As the amount of high-throughput profiling studies and mechanistic investigations of microRNAs, long non-coding RNAs and circular RNAs in joint tissues and biofluids has increased, data have emerged that suggest complex interactions among non-coding RNAs that are often overlooked as critical regulators of gene expression. Identifying these non-coding RNAs and their interactions is useful for understanding both joint health and disease. Non-coding RNAs regulate signalling pathways and biological processes that are important for normal joint development but, when dysregulated, can contribute to disease. The specific expression profiles of non-coding RNAs in various disease states support their roles as promising candidate biomarkers, mediators of pathogenic mechanisms and potential therapeutic targets. This Review synthesizes literature published in the past 2 years on the role of non-coding RNAs in OA and RA with a focus on inflammation, cell death, cell proliferation and extracellular matrix dysregulation. Research to date makes it apparent that 'non-coding' does not mean 'non-essential' and that non-coding RNAs are important parts of a complex interactome that underlies OA and RA.

KDM5B promotes self-renewal of hepatocellular carcinoma cells through the microRNA-448-mediated YTHDF3/ITGA6 axis

Histone methylation plays important roles in mediating the onset and progression of various cancers, and lysine-specific demethylase 5B (KDM5B), as a histone demethylase, is reported to be an oncogene in hepatocellular carcinoma (HCC). However, the mechanism underlying its tumorigenesis remains undefined. Hence, we explored the regulatory role of KDM5B in HCC cells, aiming to identify novel therapeutic targets for HCC. Gene Expression Omnibus database and StarBase were used to predict important regulatory pathways related to HCC. Then, the expression of KDM5B and microRNA-448 (miR-448) in HCC tissues was detected by RT-qPCR and Western blot analysis. The correlation between KDM5B and miR-448 expression was analysed by Pearson's correlation coefficient and ChIP experiments, and the targeting of YTH N6-methyladenosine RNA binding protein 3 (YTHDF3) by miR-448 was examined by luciferase assay. Additionally, the effect of KDM5B on the proliferation, migration, invasion and apoptosis as well as tumorigenicity of transfected cells was assessed using ectopic expression and depletion experiments. KDM5B was highly expressed in HCC cells and was inversely related to miR-448 expression. KDM5B demethylated H3K4me3 on the miR-448 promoter and thereby inhibited the expression of miR-448, which in turn targeted YTHDF3 and integrin subunit alpha 6 (ITGA6) to promote the malignant phenotype of HCC. Moreover, KDM5B accelerated HCC progression in nude mice via the miR-448/YTHDF3/ITGA6 axis. Our study uncovered that KDM5B regulates the YTHDF3/ITGA6 axis by inhibiting the expression of miR-448 to promote the occurrence of HCC.

Decellularized Porcine Cartilage Scaffold; Validation of Decellularization and Evaluation of Biomarkers of Chondrogenesis

Osteoarthritis is a major concern in the United States and worldwide. Current non-surgical and surgical approaches alleviate pain but show little evidence of cartilage restoration. Cell-based treatments may hold promise for the regeneration of hyaline cartilage-like tissue at the site of injury or wear. Cell-cell and cell-matrix interactions have been shown to drive cell differentiation pathways. Biomaterials for clinically relevant applications can be generated from decellularized porcine auricular cartilage. This material may represent a suitable scaffold on which to seed and grow chondrocytes to create new cartilage. In this study, we used decellularization techniques to create an extracellular matrix scaffold that supports chondrocyte cell attachment and growth in tissue culture conditions. Results presented here evaluate the decellularization process histologically and molecularly. We identified new and novel biomarker profiles that may aid future cartilage decellularization efforts. Additionally, the resulting scaffold was characterized using scanning electron microscopy, fluorescence microscopy, and proteomics. Cellular response to the decellularized scaffold was evaluated by quantitative real-time PCR for gene expression analysis.

CircATRNL1 protects against osteoarthritis by targeting miR-153-3p and KLF5

BACKGROUND

Osteoarthritis (OA) is characterized by chondrocyte injury. Circular RNAs (circRNAs) are involved in the pathogenesis of various diseases, including OA. The purpose of this study was to determine the potential role of circATRNL1 in OA pathology in vitro.

METHODS

Human chondrocytes were isolated and treated with interleukin-1 beta (IL-1β) to mimic OA in vitro. High-throughput RNA sequencing was performed to identify differentially expressed circRNAs, miRNAs and mRNAs between IL and 1β-treated chondrocytes and normal chondrocytes. The expression of circATRNL1, miR-153-3p and KLF5 was measured using quantitative real-time polymerase chain reaction (qRT-PCR). For functional analyses, cell apoptosis was assessed using a flow cytometry assay. Extracellular matrix (ECM) degradation was monitored by measuring the levels of ECM-associated proteins by Western blot. The potential target miRNAs of circATRNL1 were screened by bioinformatics analysis and verified by dual-luciferase reporter assay.

RESULTS

The expression of circATRNL1 was decreased in IL-1β-treated chondrocytes. CircATRNL1 overexpression ameliorated cell apoptosis and ECM degradation, which were promoted by IL-1β treatment. Mechanistic analysis revealed that circATRNL1 directly targeted miR-153-3p and that miR-153-3p could reverse the inhibitory effects of circATRNL1 overexpression on inflammatory responses, cell apoptosis and ECM degradation. KLF5 is a target of miR-153-3p.

CONCLUSION

Taken together, the results in this study suggested that circATRNL1 might ameliorate the development and progression of OA through regulating miR-153-3p/KLF5 axis. Our study increased the understanding of circRNAs as therapeutic targets in the treatment of OA.

MiR-485-3p promotes proliferation of osteoarthritis chondrocytes and inhibits apoptosis via Notch2 and the NF-κB pathway

CONTEXT

Osteoarthritis (OA) is one of the leading causes of disability worldwide. microRNAs (miRs) has been shown to be involved in multiple pathological processes during OA. But the possible mechanism of miR-485-3p in OA remains unclear.

OBJECTIVE

This study was designed to identify the effect of miR-485-3p on OA.

METHODS

miR-485-3p expression in the cartilage of OA patients and healthy controls was detected. OA cell model was established by lipopolysaccharide (LPS). miR-485-3p expression in SW1353 and CHON-001 chondrocytes treated with LPS was detected. After overexpressing miR-485-3p in chondrocytes, cell proliferation, and apoptosis were detected. Apoptosis-, extracellular matrix (ECM)-, inflammatory-, and oxidative stress-related factors were detected. The target gene of miR-485-3p was predicted by online software and verified by dual luciferase reporter gene assay. Notch2 was intervened in CHON-001 chondrocytes to detect proliferation and apoptosis. Finally, the phosphorylation of NF-κB pathway-related proteins was detected.

RESULTS

miR-485-3p expression was low in OA patients and LPS-treated chondrocytes. After LPS treatment, the proliferation of SW1353 and CHON-001 chondrocytes was decreased, and apoptosis was increased. The above outcomes were reversed after overexpressing miR-485-3p. Overexpressing miR-485-3p also reduced ECM degradation, inflammation and oxidative stress in chondrocytes. miR-485-3p could target Notch2. After LPS treatment, the NF-κB pathway was activated, but miR-485-3p overexpression inhibited the pathway. Notch2 inhibition promoted proliferation and inhibited apoptosis of LPS-treated CHON-001 chondrocytes, and inhibited the NF-κB pathway.

CONCLUSION

Overexpression of miR-485-3p inhibited Notch2 and the NF-κB pathway, and promoted proliferation of OA chondrocytes and inhibited apoptosis.

microRNA-130b downregulation potentiates chondrogenic differentiation of bone marrow mesenchymal stem cells by targeting SOX9

Osteoarthritis (OA) is a chronic health condition. MicroRNAs (miRs) are critical in chondrocyte apoptosis in OA. We aimed to investigate the mechanism of miR-130b in OA progression. Bone marrow mesenchymal stem cells (BMSCs) and chondrocytes were first extracted. Chondrogenic differentiation of BMSCs was carried out and verified. Chondrocytes were stimulated with interleukin (IL)-1β to imitate OA condition in vitro. The effect of miR-130b on the viability, inflammation, apoptosis, and extracellular matrix of OA chondrocytes was studied. The target gene of miR-130b was predicted and verified. Rescue experiments were performed to further study the underlying downstream mechanism of miR-130b in OA. miR-130b first increased and drastically reduced during chondrogenic differentiation of BMSCs and in OA chondrocytes, respectively, while IL-1β stimulation resulted in increased miR-130b expression in chondrocytes. miR-130b inhibitor promoted chondrogenic differentiation of BMSCs and chondrocyte growth and inhibited the levels of inflammatory factors. miR-130b targeted SOX9. Overexpression of SOX9 facilitated BMSC chondrogenic differentiation and chondrocyte growth, while siRNA-SOX9 contributed to the opposite trends. Silencing of SOX9 significantly attenuated the pro-chondrogenic effects of miR-130b inhibitor on BMSCs. Overall, miR-130b inhibitor induced chondrogenic differentiation of BMSCs and chondrocyte growth by targeting SOX9.

A Network Biology Approach to Understanding the Tissue-Specific Roles of Non-Coding RNAs in Arthritis

Discovery of non-coding RNAs continues to provide new insights into some of the key molecular drivers of musculoskeletal diseases. Among these, microRNAs have received widespread attention for their roles in osteoarthritis and rheumatoid arthritis. With evidence to suggest that long non-coding RNAs and circular RNAs function as competing endogenous RNAs to sponge microRNAs, the net effect on gene expression in specific disease contexts can be elusive. Studies to date have focused on elucidating individual long non-coding-microRNA-gene target axes and circular RNA-microRNA-gene target axes, with a paucity of data integrating experimentally validated effects of non-coding RNAs. To address this gap, we curated recent studies reporting non-coding RNA axes in chondrocytes from human osteoarthritis and in fibroblast-like synoviocytes from human rheumatoid arthritis. Using an integrative computational biology approach, we then combined the findings into cell- and disease-specific networks for in-depth interpretation. We highlight some challenges to data integration, including non-existent naming conventions and out-of-date databases for non-coding RNAs, and some successes exemplified by the International Molecular Exchange Consortium for protein interactions. In this perspective article, we suggest that data integration is a useful in silico approach for creating non-coding RNA networks in arthritis and prioritizing interactions for further in vitro and in vivo experimentation in translational research.

LncRNA DRAIC regulates cell proliferation and migration by affecting the miR-34a-5p/ITGA6 signal axis in Hirschsprung's disease

BACKGROUND

Hirschsprung's disease (HSCR) is a common defect in newborns, and studies have revealed that long non-coding RNA (lncRNA) is involved in the progression of HSCR. This research study aims to investigate the mechanism of downregulated RNA in cancer (DRAIC) on cell proliferation and migration in HSCR.

METHODS

Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was used to detect the expression of DRAIC in HSCR bowel stenosis tissues and normal colon tissues. Cell-counting kit-8 (CCK-8) and Transwell assays were employed to explore whether cellular functions change after overexpression or knockdown of the DRAIC in SH-SY5Y cells and human 293T cells. Protein expression levels were determined by Western blot analysis. RNA pull-down and dual-luciferase reporter assays were used to confirm the competitive relationship of DRAIC and integrin subunit alpha 6 (ITGA6) through their association with miR-34a-5p.

RESULTS

The lncRNA DRAIC was significantly increased in colon tissue from HSCR patients. The overexpression of DRAIC inhibited SH-SY5Y cell and human 293T cell proliferation and migration. Knockdown of DRAIC, however, promoted cell proliferation and migration. The RNA pull-down and dual-luciferase reporter assays have proven the competitive relationship between DRAIC and ITGA6 through their association with miR-34a-5p. Further rescue experiments have confirmed that DRAIC regulates cell proliferation and migration by affecting the miR-34a-5p/ITGA6 signal axis in HSCR.

CONCLUSION

DRAIC promoted cell proliferation and migration by regulating the miR-34a-5p/ITGA6 signal axis in HSCR.

LncRNA NEAT1 participates in inflammatory response in macrophages infected by mycobacterium tuberculosis through targeted regulation of miR-377-3p

Background Tuberculosis (TB) is a very serious public health problem in the world at present. The incidence rate is rising continuously. Once it develops to the middle and late stage, it can cause serious tissue damage and necrosis, directly threatening the life and health of patients. Because of its high incidence, high infectivity and high mortality, clinical research on TB has never stopped. Previous studies have confirmed the effect of macrophages on mycobacterium tuberculosis (MTB) infection, and its regulatory mechanism has not yet been fully clarified. Objective To analyze the effects of NEAT1 and miR-377-3p on macrophages infected by MTB and provide new reference for the diagnosis and treatment of TB in the future. Methods The pulmonary TB patients admitted to our hospital from July 2017 to July 2019 and the healthy cases at the same time were selected as the research objects for prospective analysis. In addition, THP-1 cells and mycobacterium tuberculosis H37Ra were purchased to construct macrophages infected by H37Ra, and the effects of NEAT1 and miR-377-3p on macrophages and their relationship with inflammatory factors were analyzed. Results NEAT1 was highly expressed in pulmonary TB patients and miR-377-3p was poorly expressed (p < 0.05). The concentrations of inflammatory factors in serum of patients with pulmonary TB were significantly higher than those in healthy cases (P < 0.001). After infection with H37Ra, the inflammatory factors in macrophages increased significantly (p < 0.001), while miR-377-3p decreased (p < 0.001). Inhibition of NEAT1 and increase of miR-377-3p could decrease inflammatory factors and proliferation ability of cells, and increase apoptosis rate (p < 0.001). The double luciferase reporter assay showed that the fluorescence activity of NEAT1-WT was inhibited by the transfection of miR-377-3pmimics (P < 0.001). Conclusion NEAT1 participates in inflammatory response in macrophages infected by MTB through targeted regulation of miR-377-3p.

miR-129-3p alleviates chondrocyte apoptosis in knee joint fracture-induced osteoarthritis through CPEB1

Background

Osteoarthritis (OA), a refractory disease, is one of the leading contributors for disability worldwide. Since chondrocyte is the only resident cell in cartilage, this study aims to explore the roles of miR-129-3p and CPEB1 in chondrocyte apoptosis in knee joint fracture-induced OA.

Methods

Cartilage was collected from 20 OA patients who underwent total knee replacement (OA group) and 20 patients with knee contusion (normal group). Then, miR-129-3p and CPEB1 levels in the cartilage were quantified by qRT-PCR. Primary rat chondrocytes in the knee were isolated and identified by toluidine blue staining and immunofluorescent staining of type II collagen. OA cellular models were induced by TNF-α treatment, in which miR-129-3p and CPEB1 expressions were assessed. Subsequently, cell viability, apoptosis, and the expression levels of apoptotic protein and caspase-3 were measured. Dual luciferase reporter assay identified the interaction between miR-129-3p and CPEB1.

Results

Patients in the OA group had decreased miR-129-3p expression and increased CPEB1 expression than those in the normal group. TNF-α treatment successfully induced the OA cellular model. Downregulated miR-129-3p and upregulated CPEB1 expressions were found in OA-treated chondrocytes. miR-129-3p overexpression or CPEB1 knockdown improved chondrocyte viability and attenuated apoptosis, and vice versa. miR-129-3p negatively regulated CPEB1, thus ameliorating apoptosis and enhancing cell viability.

Conclusion

miR-129-3p negatively targeted CPEB1 to facilitate chondrocyte viability and hamper apoptosis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-020-02070-1.

MiR-193b modulates osteoarthritis progression through targeting ST3GAL4 via sialylation of CD44 and NF-кB pathway

Osteoarthritis (OA) is a worldwide epidemic and debilitating disease. It is urgent to explore the potential molecular mechanisms of OA which has crucial roles in the treatment strategy. As a post-translational modification, sialylation mediates the progression of OA. In current study, differential expression of sialyltransferases (STs) in normal and OA cartilage tissues is detected. The ST3GAL4 expression is significantly increased and positively associated with modified Mankin's score in OA tissue. Alteration of ST3GAL4 respectively mediates the degradation of extracellular mechanisms (ECM), apoptosis and proliferation in chondrocytes. Additionally, miR-193b is identified as a direct regulatory target of ST3GAL4. Functional analysis shows that modulation of ST3GAL4 could be reversed by miR-193b. Over-expression ST3GAL4 modifies CD44 sialylation. Finally, sialylated CD44 reduces the binding capacity to lubricin and mediates the activity of the NF-кB pathway. Collectively, these researches indicate that miR-193b/ST3GAL4 axis impacts OA progression by regulating CD44 sialylation via NF-кB pathway. Our researches propose a precise molecular mechanism and provide a prospective therapeutic target in OA.

Genome-wide analysis of intermuscular bone development reveals changes of key genes expression and signaling pathways in blunt snout bream (Megalobrama amblycephala)

Intermuscular bone (IB) is a hard-boned spicule exist in lower teleost, which brings a lot of detrimental effects on palatability and economic value of blunt snout bream (Megalobrama amblycephala). Masson trichrome staining for ossific IB indicated that some osteoblasts appeared at the edge of the bone matrix and a few osteocytes are present in the center of the mineralized bone matrix. By comparing the orthologous gene families of fish with IBs and without IBs, we screened the key signaling pathways associated with IB formation. Furthermore, the transcriptomic data demonstrated the functional importance of these gene families. The candidate genes involved in chondrocyte development were highly expressed in stage 1 compared with stage 2 and stage 3, suggesting that the development process of IB might mainly involve in intramembranous ossification. Our research reveals the molecular mechanism of IBs formation, and provides molecular evidence for the further study on intermuscular boneless stains.