Long noncoding RNA expression profile in fibroblast-like synoviocytes from patients with rheumatoid arthritis

Molecular mechanism of lncRNAs in pathogenesis and diagnosis of auto-immune diseases, with a special focus on lncRNA-based therapeutic approaches

Autoimmune diseases are a diverse set of conditions defined by organ damage due to abnormal innate and acquired immune system responses. The pathophysiology of autoimmune disorders is exceedingly intricate and has yet to be fully understood. The study of long non-coding RNAs (lncRNAs), non-protein-coding RNAs with at least 200 nucleotides in length, has gained significant attention due to the completion of the human genome project and the advancement of high-throughput genomic approaches. Recent research has demonstrated how lncRNA alters disease development to different degrees. Although lncRNA research has made significant progress in cancer and generative disorders, autoimmune illnesses are a relatively new research area. Moreover, lncRNAs play crucial functions in differentiating various immune cells, and their potential relationships with autoimmune diseases have received growing attention. Because of the importance of Th17/Treg axis in auto-immune disease development, in this review, we discuss various molecular mechanisms by which lncRNAs regulate the differentiation of Th17/Treg cells. Also, we reviewed recent findings regarding the several approaches in the application of lncRNAs in the diagnosis and treatment of human autoimmune diseases, as well as current challenges in lncRNA-based therapeutic approaches to auto-immune diseases.

Efficient delivery of the lncRNA LEF1-AS1 through the antibody LAIR-1 (CD305)-modified Zn-Adenine targets articular inflammation to enhance the treatment of rheumatoid arthritis

BACKGROUNDS

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease characterized by synovial hyperplasia. Maintaining a balance between the proliferation and apoptosis of rheumatoid arthritis synovial fibroblasts (RASFs) is crucial for preventing the erosion of bone and cartilage and, ultimately, mitigating the progression of RA. We found that the lncRNA LEF1-AS1 was expressed at low levels in the RASFs and inhibited their abnormal proliferation by targeting PIK3R2 protein and regulating the PI3K/AKT signal pathway through its interaction with miR-30-5p. In this study, we fabricated a nano-drug delivery system for LEF1-AS1 using Zn-Adenine nanoparticles (NPs) as a novel therapeutic strategy against RA.

METHODS

The expression levels of LEF1-AS1, miR-30-5p, PIK3R2, p-PI3K, and p-AKT were detected in the primary RASFs and a human fibroblast-like synovial cell line (HFLS). Zn-Adenine nanoparticles (NPs) were functionalized with anti-CD305 antibody to construct (Zn-Adenine)@Ab. These NPs were then loaded with LEF1-AS1 to form (Zn-Adenine)@Ab@lncRNA LEF1-AS1. Finally, the (Zn-Adenine)@Ab@lncRNA LEF1-AS1 NPs were locally injected into a rat model with collagen-induced arthritis (CIA). The arthritic injuries in each group were evaluated by HE staining and other methods.

RESULTS

LEF1-AS1 was expressed at low levels in the primary RASFs. High expression levels of LEF1-AS1 were detected in the HFLS cells, which corresponded to a significant downregulation of miR-30-5p. In addition, the expression level of PIK3R2 was significantly increased, and that of p-PI3K and p-AKT were significantly downregulated in these cells. The (Zn-Adenine)@Ab@lncRNA LEF1-AS1 NPs significantly inhibited the proliferation of RASFs and decreased the production of inflammatory cytokines (IL-1β, IL-6, TNF-α). Intra-articular injection (IAI) of (Zn-Adenine)@Ab@lncRNA LEF1-AS1 NPs significantly alleviated cartilage destruction and joint injury in the CIA-modeled rats.

CONCLUSIONS

LEF1-AS1 interacts with miR-30-5p to inhibit the abnormal proliferation of RASFs by regulating the PI3K/AKT signal pathway. The (Zn-Adenine)@Ab NPs achieved targeted delivery of the loaded LEF1-AS1 into the RASFs, which improved the cellular internalization rate and therapeutic effects. Thus, LEF1-AS1 is a potential target for the treatment of RA.

Long noncoding RNA/circular RNA regulates competitive endogenous RNA networks in rheumatoid arthritis: molecular mechanisms and traditional Chinese medicine therapeutic significances

Rheumatoid arthritis (RA) is a systemic and autoimmune disease that is mainly featured abnormal fibroblast-like synoviocyte (FLS) proliferation and inflammatory cell infiltration. Abnormal expression or function of long noncoding RNAs (lncRNAs) and circular RNAs (circRNAs) are closely related to human diseases, including RA. There has been increasing evidence showing that in the competitive endogenous RNA (ceRNA) networks, both lncRNA and circRNA are vital in the biological functions of cells. Nevertheless, the exact mechanism of ceRNA in RA remains to be investigated. Herein, we summarized the molecular potencies of lncRNA/circRNA-mediated ceRNA networks in RA, with emphasis on the phenotypic regulation of ceRNA in the progression of RA, including regulation of proliferation, invasion, inflammation and apoptosis, as well as the role of ceRNA in traditional Chinese medicine (TCM) in the treatment of RA. In addition, we also discussed the future direction and potential clinical value of ceRNA in the treatment of RA, which may provide potential reference value for clinical trials of TCM therapy for the treatment of RA.Key messagesLong noncoding RNA/circular RNA can work as the competitive endogenous RNA sponge and participate in the pathogenesis of rheumatoid arthritis.Traditional Chinese medicine and its agents have shown potential roles in the prevention and treatment of rheumatoid arthritis via competitive endogenous RNA.

Plumbing mysterious RNAs in "dark genome" for the conquest of human diseases

Next-generation sequencing has revealed that less than 2% of transcribed genes are translated into proteins, with a large portion transcribed into noncoding RNAs (ncRNAs). Among these, long noncoding RNAs (lncRNAs) represent the largest group and are pervasively transcribed throughout the genome. Dysfunctions in lncRNAs have been found in various diseases, highlighting their potential as therapeutic, diagnostic, and prognostic targets. However, challenges, such as unknown molecular mechanisms and nonspecific immune responses, and issues of drug specificity and delivery present obstacles in translating lncRNAs into clinical applications. In this review, we summarize recent publications that have explored lncRNA functions in human diseases. We also discuss challenges and future directions for developing lncRNA treatments, aiming to bridge the gap between functional studies and clinical potential and inspire further exploration in the field.

The implication of long non-coding RNA expression profile in rheumatoid arthritis: Correlation with treatment response to tumor necrosis factor inhibitor

OBJECTIVE

This study aimed to investigate the linkage of long non-coding RNA (lncRNA) expression profile with etanercept response in rheumatoid arthritis (RA) patients.

METHODS

Peripheral blood mononuclear cell (PBMC) samples were collected from 80 RA patients prior to etanercept treatment. Samples from eight responders and eight non-responders at week 24 (W24) were proposed to RNA-sequencing, then 10 candidate lncRNAs were sorted and their PBMC expressions were validated by reverse transcription quantitative chain reaction (RT-qPCR) in 80 RA patients. Subsequently, clinical response by lncRNA (CRLnc) prediction model was established.

RESULTS

RNA-sequencing identified 254 up-regulated and 265 down-regulated lncRNAs in W24 responders compared with non-responders, which were enriched in immune or joint related pathways such as B-cell receptor signaling, osteoclast differentiation and T-cell receptor signaling pathways, etc. By reverse transcription quantitative chain reaction (RT-qPCR) validation: Two lncRNAs were correlated with W4 response, three lncRNAs were correlated with W12 response, seven lncRNAs were correlated with W24 response. Subsequently, to construct and validate CRLnc prediction model, 80 RA patients were randomly divided into test set (n = 40) and validation set (n = 40). In the test set, lncRNA RP3-466P17.2 (OR = 9.743, P = .028), RP11-20D14.6 (OR = 10.935, P = .007), RP11-844P9.2 (OR = 0.075, P = .022), and TAS2R64P (OR = 0.044, P = .016) independently related to W24 etanercept response; then CRLnc prediction model integrating these four lncRNAs presented a good value in predicting W24 etanercept response (Area Under Curve (AUC): 0.956, 95%CI: 0.896-1.000). However, in the validation set, the CRLnc prediction model only exhibited a certain value in predicting W24 etanercept response (AUC: 0.753, 95%CI: 0.536-0.969).

CONCLUSIONS

CRLnc prediction model is potentially a useful tool to instruct etanercept treatment in RA patients.

lncRNA-mediated synovitis in rheumatoid arthritis: A perspective for biomarker development

Long noncoding RNAs (lncRNAs) are a regulatory class of noncoding RNAs with a wide range of activities such as transcriptional and post-transcriptional regulations. Emerging evidence has demonstrated that various lncRNAs contribute to the initiation and progression of Rheumatoid Arthritis (RA) through distinctive mechanisms. The present study reviews the recent findings on lncRNA role in RA development. It focuses on the involvement of different lncRNAs in the main steps of RA pathogenesis including T cell activation, cytokine dysregulation, fibroblast-like synoviocyte (FLS) activation and joint destruction. Besides, it discusses the current findings on RA diagnosis and the potential of lncRNAs as diagnostic, prognostic and predictive biomarkers in Rheumatology clinic.

LncRNA HOTAIR inhibits the progression of fibroblast-like synoviocytes by sponging miRNA-106b-5p in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic progressive autoimmune disease of unknown etiology. Human fibroblast-like synoviocytes (HFLSs) are the main effector cells for synovial hyperplasia and invasion in RA. Long non-coding RNAs (lncRNAs) play key roles in several autoimmune diseases, including RA. We investigated the effects of lncRNA HOX transcript antisense intergenic RNA (HOTAIR) on the pathological behavior of HFLSs in RA. The microRNAs (miRNAs) with potential binding sites for lncRNA HOTAIR were predicted using Starbase v2.0. TargetScan (http://www.targetscan.org) was used to analyze the potential target genes of miR-106b-5p. The interactions were further verified using a dual-luciferase reporter assay. RNA and protein expression was determined using quantitative reverse transcription polymerase chain reaction (qRT-PCR) and western blotting. The proliferation, cell invasion and migration, and cell apoptosis of HFLSs in RA was detected by the 3-(4,5-dimethylthiazol)-2,5-diphenyl-tetrazolium bromide (MTT) assay, transwell assay, and flow cytometry (FCM). The dual luciferase reporter assay confirmed the interactions between lncRNA HOTAIR and miR-106b-5p and between miR-106b-5p and SMAD family member 7 (SMAD7). The qRT-PCR results indicated that the expression of lncRNA HOTAIR was markedly decreased and that of miR-106b-5p was markedly increased in HFLSs of RA. Cell proliferation, invasion, and migration of HFLSs were inhibited by lncRNA HOTAIR upregulation, and the expression of miR-106b-5p was negatively regulated by lncRNA HOTAIR in HFLSs. Apoptosis of HFLS cells was improved by the overexpression of lncRNA HOTAIR. All the effects of lncRNA HOTAIR upregulation on HFLSs were reversed after the overexpression of miR-106b-5p. Smad7 was identified as a target gene of miR-106b-5p, and the effects of downregulation of miR-106b-5p on HFLSs could be abolished by silencing Smad7. We found that lncRNA HOTAIR was significantly downregulated in the HFLSs of patients with RA. Moreover, lncRNA HOTAIR influenced cell growth, migration, invasion, and apoptosis in HFLSs through the miR-106b-5p/Smad7 axis.

CircPTTG1IP knockdown suppresses rheumatoid arthritis progression by targeting miR-431-5p/FSTL1 axis

BACKGROUND

It is observed that circular RNA (circRNA) PTTG1 interacting protein (circPTTG1IP) level is notably up-regulated in rheumatoid arthritis (RA) patients by previous study. However, its precise role and working mechanism in RA pathology remain to be clarified.

METHODS AND RESULTS

Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and Western blot assay were carried out to examine RNA and protein expression. Cell proliferation was analyzed by colony formation assay and 5-Ethynyl-2'-deoxyuridine (EdU) assay. Cell motility was assessed by transwell assays and wound healing assay. Flow cytometry (FCM) analysis was performed to assess cell apoptosis rate. Dual-luciferase reporter, RNA immunoprecipitation (RIP), and RNA-pull down assays were conducted to confirm the interaction between microRNA-431-5p (miR-431-5p) and circPTTG1IP or follistatin like 1 (FSTL1). CircPTTG1IP expression was up-regulated in the synovial tissues of RA patients and RA patients-derived fibroblast-like synoviocytes (RA-FLS). CircPTTG1IP absence suppressed the proliferation, migration, and invasion and induced the apoptosis of RA-FLS. CircPTTG1IP negatively regulated the expression of miR-431-5p by directly binding to it in RA-FLS. CircPTTG1IP interference-mediated effects in RA-FLS were largely counteracted by the silence of miR-431-5p. miR-431-5p directly interacted with the 3' untranslated region (3'UTR) of FSTL1. FSTL1 overexpression largely overturned miR-431-5p accumulation-mediated effects in RA-FLS. CircPTTG1IP positively regulated FSTL1 expression by sponging miR-431-5p in RA-FLS.

CONCLUSION

CircPTTG1IP absence suppressed RA progression through mediating miR-431-5p/FSTL1 signaling cascade.

Mesenchymal Stem Cell-Derived Extracellular Vesicles as Non-Coding RNA Therapeutic Vehicles in Autoimmune Diseases

Autoimmune diseases (ADs) are characterized by the activation of the immune system against self-antigens. More common in women than in men and with an early onset, their incidence is increasing worldwide, and this, combined with their chronic nature, is contributing to an enlarged medical and economic burden. Conventional immunosuppressive agents are designed to alleviate symptoms but do not constitute an effective therapy, highlighting a need to develop new alternatives. In this regard, mesenchymal stem cells (MSCs) have demonstrated powerful immunosuppressive and regenerative effects. MSC-derived extracellular vesicles (MSC-EVs) have shown some advantages, such as less immunogenicity, and are proposed as novel therapies for ADs. In this review, we summarize current perspectives on therapeutic options for ADs based on MSCs and MSC-EVs, focusing particularly on their mechanism of action exerted through their non-coding RNA (ncRNA) cargo. A complete state-of-the-art review was performed, centralized on some of the most severe ADs (rheumatoid arthritis, autoimmune type 1 diabetes mellitus, and systemic lupus erythematosus), giving evidence that a promising field is evolving to overcome the current knowledge and provide new therapeutic possibilities centered on MSC-EVs and their role as ncRNA delivery vehicles for AD gene therapy.

Functional Interactions Between lncRNAs/circRNAs and miRNAs: Insights Into Rheumatoid Arthritis

Rheumatoid arthritis (RA) is one of the most common autoimmune diseases that affect synovitis, bone, cartilage, and joint. RA leads to bone and cartilage damage and extra-articular disorders. However, the pathogenesis of RA is still unclear, and the lack of effective early diagnosis and treatment causes severe disability, and ultimately, early death. Accumulating evidence revealed that the regulatory network that includes long non-coding RNAs (lncRNAs)/circular RNAs (circRNAs), micro RNAs (miRNAs), and messenger RNAs (mRNA) plays important roles in regulating the pathological and physiological processes in RA. lncRNAs/circRNAs act as the miRNA sponge and competitively bind to miRNA to regulate the expression mRNA in synovial tissue, FLS, and PBMC, participate in the regulation of proliferation, apoptosis, invasion, and inflammatory response. Thereby providing new strategies for its diagnosis and treatment. In this review, we comprehensively summarized the regulatory mechanisms of lncRNA/circRNA-miRNA-mRNA network and the potential roles of non-coding RNAs as biomarkers and therapeutic targets for the diagnosis and treatment of RA.

Long Non-Coding RNA PVT1 and Its Target miRNA-146a as Potential Prognostic Biomarkers in Rheumatoid Arthritis Patients

Objective: Long non-coding RNAs (lncRNAs) and their target microRNAs were documented in multiple studies to have a significant role in different joint disorders such as rheumatoid arthritis (RA) and osteoarthritis (OA). The current work aimed to determine the potential role of lnc-PVT1 and miR-146a as promising biomarkers to distinguish between RA, OA patients, and healthy individuals. Methods: The expression levels of lnc-PVT1 and its target miR-146a in the serum were measured for three different groups, including patients with RA (40), OA patients (40), and healthy controls (HCs) (40). Participating individuals were subjected to a full history investigation and clinical examination. Blood samples were tested for ESR, RF, CBC, as well as liver and renal functions. Serum was used to detect the relative expression levels of lnc-PVT1 and miR-146a and we correlated the levels with RA and OA activity and severity signs. Results: Lnc-PVT1 expression level was greater among patients with RA compared to that of OA patients, with a fold change median of 2.62 and 0.22, respectively (p = 0.001). The miR-146a fold change was significantly demonstrated between the RA, OA, and HCs groups. There was no correlation between both biomarkers with the disease activity scales (DAS28) of RA, the Knee injury Osteoarthritis Outcome Score (KOOS), or any sign of detection of the disease severity of OA. Conclusions: lnc-PVT1 and miR-146a could be considered as promising biomarkers for the diagnosis of RA and OA and may have an important role as therapeutic targets in the future.

Long Non-Coding RNA NEAT1 Knockdown Alleviates Rheumatoid Arthritis by Reducing IL-18 through p300/CBP Repression

Rheumatoid arthritis (RA) is chronic inflammatory autoimmune disease. The crucial role of long non-coding RNA (lncRNA) in the progression of RA has been highlighted. Hence, this study was designed to explore the specific downstream mechanism of lncRNA nuclear-enriched abundant transcript 1 (NEAT1) in RA. Initially, the expression of NEAT1, p-p65, p300, and IL-18 in clinical tissues and cells was determined. Then, interactions among p65, NEAT1, p300, CBP, and IL-18 were investigated by immunofluorescence staining, dual luciferase reporter gene assay, RT-qPCR assay ChIP assay, and RIP assay followed by the analysis of their effects on RA in vivo and in vitro after expression alteration. The expressions of NEAT1, p-p65, p300, and IL-18 were all upregulated in the synovial tissues from the mice and patients with RA. NEAT1 silencing reduced the infiltration of CD4⁺ T cells and macrophages in synovial tissues, downregulated expression of blood inflammatory factors, relieved RA severity, and lowered incidence of RA in mice. Further, p-p65 could increase the expression of NEAT1 by binding to the NEAT1 promoter region, NEAT1 could co-locate and interact with p300, thus regulating the expression of IL-18 by regulating histone acetylation modification in IL-18 promoter region. NEAT1 aggravated RA via p300/CBP/IL-18 axis, representing a promising therapeutic target in RA.

Circular RNA circ_0008360 Inhibits the Proliferation, Migration, and Inflammation and Promotes Apoptosis of Fibroblast-Like Synoviocytes by Regulating miR-135b-5p/HDAC4 Axis in Rheumatoid Arthritis

Circular RNAs (circRNAs) have been demonstrated to play crucial roles in the development and progression of many diseases, including rheumatoid arthritis (RA). However, the functions and molecular mechanism of circ_0008360 in RA remain unclear. Quantitative real-time polymerase chain reaction (qRT-PCR) was employed to determine the expression of circ_0008360, microRNA-135b-5p (miR-135b-5p), and histone deacetylase 4 (HDAC4). Cell Counting Kit-8 (CCK-8) assay, wound healing assay, and flow cytometry analysis were performed to assess cell proliferation, migration, and apoptosis, respectively. Inflammatory response was evaluated by enzyme-linked immunosorbent assay (ELISA). The interaction between miR-135b-5p and circ_0008360 or HDAC4 was predicted by bioinformatics analysis and verified by dual-luciferase reporter and RNA Immunoprecipitation (RIP) and RNA pull-down assays. Western blot assay was used to detect the protein expression of HDAC4 and proliferating cell nuclear antigen (PCNA). The expression of circ_0008360 was downregulated in RA synovial tissues and RA fibroblast-like synoviocytes (RA-FLSs). Circ_0008360 suppressed the proliferation, migration, and inflammation and promoted apoptosis of RA-FLSs, and circ_0008360 knockdown showed opposite effects. Moreover, miR-135b-5p was a direct target of circ_0008360, and miR-135b-5p could reverse the effects of circ_0008360 on proliferation, migration, inflammation, and apoptosis in RA-FLSs. Furthermore, HDAC4 was a downstream target of miR-135b-5p, and miR-135b-5p accelerated the proliferation, migration, and inflammation and suppressed apoptosis of RA-FLSs by targeting HDAC4. In addition, circ_0008360 positively regulated HDAC4 expression by sponging miR-135b-5p. Circ_0008360 inhibited the proliferation, migration, and inflammation and facilitated apoptosis of RA-FLSs by sponging miR-135b-5p and upregulating HDAC4, providing a potential target for prevention and treatment of RA.

LncRNA ZNF667-AS1 alleviates rheumatoid arthritis by sponging miR-523-3p and inactivating the JAK/STAT signalling pathway

BACKGROUND

Rheumatoid arthritis (RA) is an autoimmune disease, which compromises the synovial membrane resulting in chronic inflammation. Increasing evidence has demonstrated that long non-coding RNAs (lncRNAs) are implicated in the pathogenesis of RA. This study investigated the role of lncRNA ZNF667-AS1 in RA progression.

METHODS

Synovial tissues and fibroblast-like synoviocytes (FLSs) were obtained from patients with RA. Gene expression was measured using RT-qPCR. Chondrocytes were treated with lipopolysaccharide (LPS) to establish in vitro models of OA. Cell counting kit-8 (CCK-8), western blot, and enzyme-linked immunosorbent assay (ELISA) were used to examine the proliferation and inflammatory cytokine production in chondrocytes. Animal models of OA were established in SD rats. Peripheral blood mononuclear cells (PBMCs) were isolated from the OA rats. Flow cytometry was used to measure the changes of the inflammatory T-helper cell 17 (Th17) cells. The relationship between ZNF667-AS1 and miR-523-3p was verified by luciferase reporter assay.

RESULTS

ZNF667-AS1 was downregulated in RA-FLSs and LPS-stimulated chondrocytes. ZNF667-AS1 overexpression significantly promoted cell proliferation and inhibited the production of IL-6, IL-17 and TNF-α in LPS-stimulated chondrocytes. Additionally, ZNF667-AS1 overexpression reduced the generation of CD4 + IL-17+ cells. In mechanism, ZNF667-AS1 acted a sponge for miR-523-3p. MiR-523-3p overexpression reversed the ZNF667-AS1-mediated regulation of cell proliferation and inflammation. Furthermore, miR-523-3p overexpression abolished the inhibitory effects of ZNF667-AS1 on the JAK/STAT signalling activation.

CONCLUSION

ZNF667-AS1 exerts protective effects during RA development by sponging miR-523-3p and inactivating the JAK/STAT signalling.

Dysregulation of lncRNAs in autoimmune neuropathies

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and Guillain-Barré syndrome (GBS) are inflammatory neuropathies with different clinical courses but similar underlying mechanisms. Long non-coding RNAs (lncRNAs) might affect pathogenesis of these conditions. In the current project, we have selected HULC, PVT1, MEG3, SPRY4-IT1, LINC-ROR and DSCAM-AS1 lncRNAs to appraise their transcript levels in the circulation of CIDP and GBS cases versus controls. Expression of HULC was higher in CIDP patients compared with healthy persons (Ratio of mean expression (RME) = 7.62, SE = 0.72, P < 0.001). While expression of this lncRNA was not different between female CIDP cases and female controls, its expression was higher in male CIDP cases compared with male controls (RME = 13.50, SE = 0.98, P < 0.001). Similarly, expression of HULC was higher in total GBS cases compared with healthy persons (RME = 4.57, SE = 0.65, P < 0.001) and in male cases compared with male controls (RME = 5.48, SE = 0.82, P < 0.001). Similar pattern of expression was detected between total cases and total controls. PVT1 was up-regulated in CIDP cases compared with controls (RME = 3.04, SE = 0.51, P < 0.001) and in both male and female CIDP cases compared with sex-matched controls. Similarly, PVT1 was up-regulated in GBS cases compared with controls (RME = 2.99, SE = 0.55, P vale < 0.001) and in total patients compared with total controls (RME = 3.02, SE = 0.43, P < 0.001). Expression levels of DSCAM-AS1 and SPRY4-IT1 were higher in CIDP and GBS cases compared with healthy subjects and in both sexes compared with gender-matched healthy persons. Although LINC-ROR was up-regulated in total CIDP and total GBS cases compared with controls, in sex-based comparisons, it was only up-regulated in male CIDP cases compared with male controls (RME = 3.06, P = 0.03). Finally, expression of MEG3 was up-regulated in all subgroups of patients versus controls except for male GBS controls. SPRY4-IT could differentiate CIDP cases from controls with AUC = 0.84, sensitivity = 0.63 and specificity = 0.97. AUC values of DSCAM-AS1, MEG3, HULC, PVT1 and LINC-ROR were 0.80, 0.75, 0.74, 0.73 and 0.72, respectively. In differentiation between GBS cases and controls, SPRY4-IT and DSCAM-AS1 has the AUC value of 0.8. None of lncRNAs could appropriately differentiate between CIDP and GBS cases. Combination of all lncRNAs could not significantly enhance the diagnostic power. Taken together, these lncRNAs might be involved in the development of CIDP or GBS.

Promising Therapeutic Targets for Treatment of Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a systemic poly-articular chronic autoimmune joint disease that mainly damages the hands and feet, which affects 0.5% to 1.0% of the population worldwide. With the sustained development of disease-modifying antirheumatic drugs (DMARDs), significant success has been achieved for preventing and relieving disease activity in RA patients. Unfortunately, some patients still show limited response to DMARDs, which puts forward new requirements for special targets and novel therapies. Understanding the pathogenetic roles of the various molecules in RA could facilitate discovery of potential therapeutic targets and approaches. In this review, both existing and emerging targets, including the proteins, small molecular metabolites, and epigenetic regulators related to RA, are discussed, with a focus on the mechanisms that result in inflammation and the development of new drugs for blocking the various modulators in RA.

LncRNA XIST is involved in rheumatoid arthritis fibroblast-like synoviocytes by sponging miR-126-3p via the NF-κB pathway

The role and mechanism of lncRNA XIST (XIST) in the development of rheumatoid arthritis (RA) was explored in this study. RT-qPCRs were performed to detect the expression of XIST and miR-126-3p in synovial tissues and cells. Target gene prediction and luciferase gene reporter assay were used to validate downstream target genes of XIST. MTT assay, EdU staining and Annexin V/PI staining were performed to explore the effects of XIST and miR-126-3p on cell proliferation and apoptosis. Western blotting analysis was used to detect the expression of related proteins. We found that the expression levels of XIST in tissues and cells were significantly higher than that in normal tissues and cells. Down-regulation of XIST could inhibit cell proliferation rate and increase apoptosis rate. Luciferase gene reporter assay showed that miR-126-3p was a downstream target gene of XIST. Overexpression of miR-126-3p significantly inhibited RA-FLS cell proliferation and induced RA-FLS cell apoptosis. In addition, down-regulation of XIST could increase the ratio of caspase-3 and Bax/Bcl-2. In addition, overexpression of miR-126-3p could inhibit the NF-κB signalling pathway by reducing the expression levels of p-p65 and p-IκBα in RA-FLS cells. In conclusion, down-regulation of XIST can inhibit the proliferation of synovial fibroblasts by increasing the expression levels of miR-126-3p/NF-κB, thereby inhibiting the occurrence and development of RA.

CircMAPK9 promotes the progression of fibroblast-like synoviocytes in rheumatoid arthritis via the miR-140-3p/PPM1A axis

Background

Rheumatoid arthritis (RA) is a chronic inflammatory joint disease, and fibroblast-like synoviocytes (FLSs) are key effector cells in RA development. Mounting evidence indicates that circular RNAs (circRNAs) participate in the occurrence and development of RA. However, the precise mechanism of circRNA mitogen-activated protein kinase (circMAPK9) in the cell processes of FLSs has not been reported.

Methods

The expression levels of circMAPK9, microRNA-140-3p (miR-140-3p), and protein phosphatase magnesium-dependent 1A (PPM1A) were determined by quantitative real-time polymerase chain reaction (qRT-PCR) or western blot assay. Cell proliferation was examined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Cell apoptosis and cycle distribution were assessed by flow cytometry. Cell migration and invasion were tested by transwell assay. All the proteins were inspected by western blot assay. Inflammatory response was evaluated by enzyme-linked immunosorbent assay (ELISA). The interaction between miR-140-3p and circMAPK9 or PPM1A was verified by dual-luciferase reporter assay.

Results

CircMAPK9 and PPM1A were upregulated and miR-140-3p was downregulated in RA patients and FLSs from RA patients (RA-FLSs). CircMAPK9 silence suppressed cell proliferation, migration, invasion, inflammatory response, and promoted apoptosis in RA-FLSs. MiR-140-3p was a target of circMAPK9, and miR-140-3p downregulation attenuated the effects of circMAPK9 knockdown on cell progression and inflammatory response in RA-FLSs. PPM1A was targeted by miR-140-3p, and circMAPK9 could regulate PPM1A expression by sponging miR-140-3p. Furthermore, miR-140-3p could impede cell biological behaviors in RA-FLSs via targeting PPM1A.

Conclusion

CircMAPK9 knockdown might inhibit cell proliferation, migration, invasion, inflammatory response, and facilitate apoptosis in RA-FLSs via regulating miR-140-3p/PPM1A axis, offering a new mechanism for the comprehension of RA development and a new insight into the potential application of circMAPK9 in RA treatment.

LncRNA FOXD2-AS1 promotes cell proliferation and invasion of fibroblast-like synoviocytes by regulation of miR-331-3p/PIAS3 pathway in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune disorder that leads to systemic inflammation of diarthrodial joint, synovial hyperplasia, cartilage damage, and ultimately joint destruction and deformity. As the dominant non-immune cells in the synovium, fibroblast-like synoviocytes (FLSs) significantly contribute to the deterioration of RA. Our study aimed to explore the regulatory role of long non-coding RNA FOXD2-AS1 in RA progression. Compared to patients with joint trauma, the expression of FOXD2-AS1 was elevated in serum and synovial tissue samples of RA patients. FOXD2-AS1 knockdown inhibited the proliferation and invasion of rheumatoid FLSs but restored their apoptotic ability. Furthermore, FOXD2-AS1 acted as a sponge for microRNA (miR)-331-3p. The expressions of FOXD2-AS1 and miR-331-3p in synovial tissues of RA patients were negatively correlated. Protein inhibitor of activated STAT 3 (PIAS3) was predicted as a downstream target of miR-331-3p. The expressions of FOXD2-AS1 and PIAS3 in synovial tissues of RA patients were positively correlated, whereas a negative correlation was observed between the levels of miR-331-3p and PIAS3. Moreover, increased proliferation and invasion of rheumatoid FLSs induced by FOXD2-AS1 overexpression was inhibited by the knockdown of PIAS3. In summary, this study demonstrated that FOXD2-AS1 promoted RA progression via regulating the miR-331-3p/PIAS3 pathway, suggesting that therapeutic strategies based on the FOXD2-AS1/miR-331-3p/PIAS3 axis may represent a promising treatment approach for RA patients.

Lnc RNA ZFAS1 regulates the proliferation, apoptosis, inflammatory response and autophagy of fibroblast-like synoviocytes via miR-2682-5p/ADAMTS9 axis in rheumatoid arthritis

Backgrounds: Rheumatoid arthritis (RA) is a frequent autoimmune disease. Emerging evidence indicated that ZNFX1 antisense RNA1 (ZFAS1) participates in the physiological and pathological processes in RA. However, knowledge of ZFAS1 in RA is limited, the potential work pathway of ZFAS1 needs to be further investigated.

Methods: Levels of ZFAS1, microRNA (miR)-2682-5p, and ADAM metallopeptidase with thrombospondin type 1 motif 9 (ADAMTS9) were estimated using quantitative real-time polymerase chain reaction (qRT-PCR) assay. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was conducted to explore the ability of cell proliferation in fibroblast-like synoviocytes (FLS-RA). Cell apoptosis was measured via flow cytometry. Also, levels of ADAMTS9, apoptosis-related proteins, cleaved-caspase-3 (active large subunit), and autophagy-related proteins were identified adopting Western blot. Enzyme-linked immunosorbent assay (ELISA) was performed to determine the productions of inflammatory cytokines. Beside, the interrelation between miR-2682-5p and ZFAS1 or ADAMTS9 was verified utilizing dual-luciferase reporter assay.

Results: High levels of ZFAS1 and ADAMTS9, and a low level of miR-2682-5p were observed in RA synovial tissues and FLS-RA. Knockdown of ZFAS1 led to the curbs of cell proliferation, inflammation, autophagy, and boost apoptosis in FLS-RA, while these effects were abolished via regaining miR-2682-5p inhibition. Additionally, the influence of miR-2682-5p on cell phenotypes and inflammatory response were eliminated by ADAMTS9 up-regulation in FLS-RA. Mechanically, ZFAS1 exerted its role through miR-2682-5p/ADAMTS9 axis in RA.

Conclusion: ZFAS1/miR-2682-5p/ADAMTS9 axis could modulate the cell behaviors, inflammatory response in FLS-RA, might provide a potential therapeutic target for RA treatment.

Expression Profile of Osteoclasts Following the Stimulation With Interleukin-23 in Mice

Objectives

This study aims to analyze the expression profile of osteoclasts (OCs) following the stimulation with interleukin 23 (IL-23) in mice, which would imply the underlying effects of IL-23 on the function of OCs in inflammatory arthritis.

Materials and methods

Mature OCs were induced from bone marrow mononuclear cells of 5 male mice (age 6 weeks; weighing 18-20 g) in the presence of macrophage-colony stimulating factor (50 ng/mL) and receptor activator of nuclear factor kappa B ligand (30 ng/mL) in vitro. The Agilent SurePrint G3 Mouse GE V2.0 Microarray was used to analyze the gene expression profile of OCs stimulated with IL-23 (30 ng/mL) or vehicle. The four major IL-23-modulated genes were validated by quantitative real-time polymerase chain reaction (qPCR) analysis.

Results

The expression levels of 23 genes were up-regulated and 32 genes were down-regulated by IL-23 stimulation (fold change ≥1.5 and p value <0.05). Among them, there were 37 genes with assigned gene symbols. Gene ontology analysis showed that the IL-23-regulated messenger ribonucleic acids (mRNAs) were related to positive regulation of leukocyte chemotaxis, chemokine-mediated signaling pathway and C-X-C chemokine receptors binding. The pathway analysis showed that the IL-23-regulated mRNAs were related to chemokine signaling pathway and cytokine-cytokine receptor interaction. The significant up-regulation of chemokine (C-X-C motif) ligand 1 and chemokine (C-X-C motif) ligand 2 induced by IL-23 was confirmed by qPCR. In addition, there were 18 long non-coding RNAs that were regulated by IL-23, while their function needs to be confirmed in the future.

Conclusion

Expression levels of genes related to chemotaxis in OCs were up-regulated by IL-23 in mice, which imply that IL-23 may facilitate chemotaxis of OCs in inflammatory arthritis.

Dysregulation of lncRNAs in Rheumatoid Arthritis: Biomarkers, Pathogenesis and Potential Therapeutic Targets

Rheumatoid arthritis (RA) is a chronic autoimmune disease of unknown etiology, mainly manifested by persistent abnormal proliferation of fibroblast-like synoviocytes (FLSs), inflammation, synovial hyperplasia and cartilage erosion, accompanied by joint swelling and joint destruction. Abnormal expression or function of long noncoding RNAs (lncRNAs) are closely related to human diseases, including cancers, mental diseases, autoimmune diseases and others. The abnormal sequence and spatial structure of lncRNAs, the disorder expression and the abnormal interaction with the binding protein will lead to the change of gene expression in the way of epigenetic modification. Increasing evidence demonstrated that lncRNAs were involved in the activation of FLSs, which played a key role in the pathogenesis of RA. In this review, the research progress of lncRNAs in the pathogenesis of RA was systematically summarized, including the role of lncRNAs in the diagnosis of RA, the regulatory mechanism of lncRNAs in the pathogenesis of RA, and the intervention role of lncRNAs in the treatment of RA. Furthermore, the activated signal pathways, the role of DNA methylation and other mechanism have also been overview in this review.

LncRNAs Landscape in the patients of primary gout by microarray analysis

To determine the expression profile and clinical significance of long non-coding RNAs (lncRNAs) in peripheral blood mononuclear cells (PBMCs) of patients with primary gout and healthy control subjects. Human lncRNA microarrays were used to identify the differentially expressed lncRNAs and mRNAs in primary gout patients (n = 6) and healthy control subjects (n = 6). Bioinformatics analyses were performed to predict the roles of differently expressed lncRNAs and mRNAs. Quantitative real-time polymerase chain reaction (qRT-PCR) was performed to detect the expression levels of 8 lnRNAs in 64 primary gout patients and 32 healthy control subjects. Spearman’s correlation was used to analyze the correlation between these eight lncRNAs and the laboratory values of gout patients. A receiver operating characteristic (ROC) curve was constructed to evaluate the diagnostic value of the lncRNAs identified in gout. The microarray analysis identified 1479 differentially expressed lncRNAs (879 more highly expressed and 600 more lowly expressed), 862 differentially expressed mRNAs (390 more highly expressed and 472 more lowly expressed) in primary gout (fold change > 2, P < 0.05), respectively. The bioinformatic analysis indicated that the differentially expressed lncRNAs regulated the abnormally expressed mRNAs, which were involved in the pathogenesis of gout through several different pathways. The expression levels of TCONS_00004393 and ENST00000566457 were significantly increased in the acute gout flare group than those in the intercritical gout group or healthy subjects (P<0.01). Moreover, inflammation indicators were positive correlated with TCONS_00004393 and ENST00000566457 expression levels. The areas under the ROC curve of ENST00000566457 and NR-026756 were 0.868 and 0.948, respectively. Our results provide novel insight into the mechanisms of primary gout, and reveal that TCONS_00004393 and ENST00000566457 might be as candidate targets for the treatment of gout flare; ENST00000566457 and NR-026756 could effectively discriminate between the gout and the healthy control groups.

Expression profiles of long non-coding RNAs in the cartilage of patients with knee osteoarthritis and normal individuals

Knee osteoarthritis is caused by a multifactorial imbalance in the synthesis and degradation of knee chondrocytes, subchondral bone and extracellular matrix. Abnormal expression of long non-coding RNAs (lncRNAs) affects the metabolism, synovitis, autophagy and apoptosis of chondrocytes, as well as the production of cartilage matrix. The aim of the present study was to identify novel targets for the treatment of osteoarthritis and to examine the pathogenesis of the disease. The lncRNA expression profiles of seven patients with knee osteoarthritis and six healthy controls were examined by RNA-sequencing. Differentially expressed lncRNAs were selected for bioinformatics analyses, including Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment. Reverse transcription-quantitative PCR (RT-qPCR) was used to further investigate the differential expression of the lncRNAs. A total of 23,583 lncRNAs were identified in osteoarthritis cartilage, including 5,255 upregulated and 5,690 downregulated lncRNAs, compared with normal cartilage. Although there were more downregulated lncRNAs compared with upregulated lncRNAs, among the changed lncRNAs (fold-change >6), there were more upregulated lncRNAs compared with downregulated lncRNAs. Several lncRNAs exhibiting differences were identified as potential therapeutic targets in knee osteoarthritis. GO and KEGG pathway analyses were performed for the target genes of the differentially expressed lncRNAs. RT-qPCR validation was performed on three randomly selected upregulated and downregulated lncRNAs. The results of RT-qPCR were consistent with the findings obtained by RNA-sequencing analysis. The findings from the present study may contribute to the diagnosis of osteoarthritis and may predict the development of osteoarthritis. Furthermore, the differentially expressed lncRNAs may aid in the identification of novel candidate targets for the treatment of knee osteoarthritis.

Insights of rheumatoid arthritis biomarkers

Rheumatoid arthritis is a chronic, autoimmune connective tissue disease. In addition to joint involvement, extra-articular changes and organ complications also occur in the course of the disease. Untreated disease leads to disability and premature death. Therefore, it is important to recognise and begin treatment early. Based on the presence of rheumatoid factor and antibodies against citrullinated peptides, we can distinguish two forms of the disease: seropositive and seronegative. Research continues to elucidate the mechanisms of the onset of the disease, as well as to uncover factors that induce and influence the activity of the disease. The presence of markers that initially appear and affect the course of the disease can potentially aid in patient treatment. In this article, we have collected biomarkers of rheumatoid arthritis that are well understood as well as those that have been recently described.

Involvement of long non-coding RNAs in the pathogenesis of rheumatoid arthritis

Long non-coding RNA (lncRNA) plays a contributory role in rheumatoid arthritis (RA). In this review, we summarized the current findings of lncRNAs in RA, including cellular function and the potential mechanisms. Serum lncRNA levels are associated with serum proinflammatory cytokines and disease activity. LncRNAs regulate proliferation, migration, invasion and apoptosis of RA fibroblast-like synoviocytes (FLSs), modulate the differentiation of T lymphocytes and macrophages, and affect bone formation-destruction balance of chondrocytes. Besides, lncRNAs are involved in inflammation and cell motivation signaling pathways. In-depth research on lncRNAs may help elucidate the pathogenesis of RA and provides clues for novel treatment targets.

Silencing long non-coding RNA NEAT1 attenuates rheumatoid arthritis via the MAPK/ERK signalling pathway by downregulating microRNA-129 and microRNA-204

The participation of long noncoding RNAs (lncRNAs) and microRNAs (miRs) in the progression of rheumatoid arthritis (RA) is a key area of investigation. The current study aimed to investigate the action of lncRNA nuclear paraspeckle assembly transcript 1 (NEAT1) in fibroblast-like synoviocyte (FLS) proliferation and synovitis in RA. A rat model of RA was established. LncRNA NEAT1 expression in the synovial tissues of patients with RA and FLSs from the RA rat model was determined using RT-qPCR. Next, dual luciferase reporter gene assay was applied to investigate the relationship between miR-129/204 and mitogen-activated protein kinase (MAPK)/extracellular regulated protein kinase (ERK). A putative binding relationship between miR-204 and lncRNA NEAT1 was evaluated by RIP assay, and miR-129 promoter methylation was determined using MSP. After the expression of lncRNA NEAT1, miR-129 or miR-204 was altered in FLSs, the extent of ERK1/2 phosphorylation was assessed. In addition, FLS synovitis and proliferation were determined by ELISA and EdU assay, respectively. In RA rats, lncRNA NEAT1 was silenced and miR-129/miR-204 was overexpressed to explore their roles in vivo. LncRNA NEAT1 was upregulated, while miR-129 and miR-204 were downregulated in RA synovial tissues and FLSs. MAPK1 was target gene of both miR-129 and miR-204. LncRNA NEAT1 bound to miR-204 and promoted miR-129 promoter methylation. Silencing lncRNA NEAT1 or overexpressing miR-129/miR-204 enhanced miR-129/miR-204 expression, but reduced the extent of ERK1/2 phosphorylation, proliferation of FLSs, and synovitis in RA. Collectively, silencing lncRNA NEAT1 promoted miR-129 and miR-204 to inhibit the MAPK/ERK signalling pathway, reducing FLS synovitis in RA.Abbreviations: ACR: American College of Rheumatology; ELISA: Enzyme-linked immunosorbent assay; ERK: extracellular signal-regulated kinase; FLS: fibroblast-like synoviocyte; GADPH: glyceraldehyde-3-phosphate dehydrogenase; HRP: horseradish peroxidase; IFA: Incomplete Freund's Adjuvant; lncRNAs: long noncoding RNAs; MSP: Methylation-specific PCR; NC: negative control; NEAT1: nuclear paraspeckle assembly transcript 1; OD: optical density; RA: rheumatoid arthritis; RIPA: Radio Immunoprecipitation Assay; RLU: relative light units; RT-qPCR: reverse transcription quantitative polymerase chain reaction; UTR: untranslated region.

Suppression of lncRNA MALAT1 reduces pro-inflammatory cytokines production by regulating miR-150-5p/ZBTB4 axis through JAK/STAT signal pathway in systemic juvenile idiopathic arthritis

Systemic juvenile idiopathic arthritis (sJIA) is a common chronic disease occurring in children. Increasing studies have demonstrated that long noncoding RNAs (lncRNAs) play important roles in the pathogenesis of diverse human diseases. This study aimed to explore the role of lncRNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) and its mechanism in sJIA. We found that the expression of MALAT1, the plasma level of pro-inflammatory cytokines (IL-6, IL-17, IL-1β, and TNF-α) as well as MMP-8 and MMP-9 production were significantly elevated in sJIA patients. Moreover, we observed that the production of these cytokines in peripheral blood mononuclear cells (PBMCs) from sJIA patients were reduced after MALAT1 knockdown. Furthermore, bioinformatics analysis predicted that MALAT1 might bind to miR-150-5p and ZBTB4 was a downstream target gene of miR-150-5p. Besides, rescue assays revealed that MALAT1 knockdown-mediated suppressive effects on cytokine production could be reversed by ZBTB4 overexpression. In addition, MALAT1 activated the JAK/STAT signaling by upregulating ZBTB4 expression. In summary, our findings demonstrated that MALAT1 promoted pro-inflammatory cytokine and MMP production by targeting the miR-150-5p/ZBTB4 axis through JAK/STAT signaling pathway in sJIA, suggesting that MALAT1 may have a potential diagnostic biomarker for the pathogenesis and therapy of sJIA.

LncRNA LOC100912373 modulates PDK1 expression by sponging miR-17-5p to promote the proliferation of fibroblast-like synoviocytes in rheumatoid arthritis

Rheumatoid arthritis (RA) is a common autoimmune disease and characterized by chronic inflammation, abnormal synovial cell proliferation, and joint swelling and tenderness, and it causes patients substantial pain. To date, the pathogenesis of RA remains unclear, and specific treatment is still lacking in the clinic. Evidence from previous research indicated that the long noncoding RNA (lncRNA) LOC100912373 is a key lncRNA and involved in RA. However, our understanding of the specific mechanism of lncRNA LOC100912373 in RA development and progression is still in its infancy. In this study, fibroblast-like synoviocytes (FLSs) were cultured by enzyme-dispersed and substrate-attached explant methods. The MTT method, flow cytometry and transmission electron microscopy were used to determine the effect of lncRNA LOC100912373 on FLSs. The expression of key genes such as lncRNA LOC100912373, miR-17-5p, PDK1 and AKT in FLSs was detected by RT-qPCR, immunofluorescence and Western blot. The localization of lncRNA LOC100912373 was determined by fluorescence in situ hybridization. The specific targeting relationship between lncRNA LOC100912373 and miR-17-5p/PDK1 was verified by RNA immunoprecipitation and luciferase reporter gene analysis. The results showed that lncRNA LOC100912373 localized in the cytoplasm and was highly expressed in the synovial tissues and FLSs of AA rats. LncRNA LOC100912373 overexpression promoted the proliferation of FLSs. In addition, lncRNA LOC100912373 could bind to miR-17-5p, and the expression of lncRNA LOC100912373 was negatively correlated with miR-17-5p and positively correlated with PDK1/AKT. In conclusion, lncRNA LOC100912373 may upregulate the expression of PDK1 by sponging miR-17-5p, accelerating the phosphorylation of AKT and inducing the proliferation of FLSs, thus promoting the occurrence and development of RA.

<p>Transcriptome Analysis of Dorsal Root Ganglion in Rats with Knee Joint Inflammation</p>

Background

Methods

Results

Conclusion

Long non-coding RNA PVT1 can regulate the proliferation and inflammatory responses of rheumatoid arthritis fibroblast-like synoviocytes by targeting microRNA-145-5p

Long non-coding RNAs (lncRNAs) function in rheumatoid arthritis (RA). The present work was designed to explore the roles of lncRNA PVT1 in RA and the related mechanism. Quantitative real-time polymerase chain reaction (qRT-PCR) was performed to determine mRNA level. The binding sites between PVT1 and miR-145-5p were verified by a dual-luciferase reporter assay. Furthermore, RA-FLSs were treated with TNF-α to establish the RA model. 3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) and 5-ethynyl-2'-deoxyuridine (EdU) assays were performed to detect cell proliferation. Flow cytometry and TUNEL assays were performed to detect cell apoptosis. Enzyme-linked immunosorbent assay (ELISA) was used to determine levels of inflammatory cytokines. PVT1 was significantly increased and miR-145-5p was decreased in synovial tissues of RA patients. miR-145-5p is a target miRNA of PVT1, and the levels of PVT1 and miR-145-5p in synovial tissues of RA patients were negatively correlated. In RA-FLSs, tumour necrosis factor-α (TNF-α) led to increased PVT1 levels and decreased miR-145-5p levels. Knockdown of PVT1 inhibited TNF-α-induced RA-FLS over-proliferation and reversed TNF-α-induced RA-FLS apoptosis reduction. Moreover, knockdown of PVT1 inhibited TNF-α-induced production of interleukin (IL)-1β and IL-6 and the activation of NF-κB through miR-145-5p. PVT1 can regulate apoptosis and inflammatory responses in RA-FLSs by targeting miR-145-5p.

Associations of genetic polymorphisms within MALAT1, UCA1, FAM211A-AS1 and AC000111.6 with genetic susceptibility to rheumatoid arthritis

Recently, several long non-coding RNAs (lncRNAs) including MALAT1, UCA1, ENST00000483588, and ENST00000456270 have been implicated in the pathogenesis of rheumatoid arthritis (RA), and we hypothesized that polymorphisms within these lncRNA genes might be genetic modifiers for the development of RA. A total of 10 potentially functional single-nucleotide polymorphisms (SNPs) were selected and genotyped in 1198 participants, including 594 RA patients and 604 healthy controls. Significant associations of FAM211A-AS1 rs2882581 (G vs. A, OR = 1.31, 95%CI 1.07-1.62, p = .01; G/G + A/G vs. A/A, OR = 1.40, 95%CI 1.08-1.83, p = .01), rs3744281 (T vs. A, OR = 1.25, 95%CI 1.02-1.54, p = .03; T/T vs. A/T + A/A, OR = 1.69, 95%CI 1.01-2.82, p = 4.59 × 10^-2), and rs3760235 (A vs. G, OR = 1.32, 95%CI 1.04-1.68, p = .02; A/A vs. A/G + G/G, OR = 1.32, 95%CI 1.00-1.74, p = 4.89 × 10^-2) with RF-positive RA were found. Functional annotation results indicated that these identified polymorphisms might regulate the expression of FAM211A-AS1 and nearby genes via impacting on transcription factor binding. Taken together, our results indicated that FAM211A-AS1 rs2882581, rs3744281, and rs3760235 were involved in the genetic background of RF-positive RA.

Long non-coding RNA XIST binding to let-7c-5p contributes to rheumatoid arthritis through its effects on proliferation and differentiation of osteoblasts via regulation of STAT3

BACKGROUND

Rheumatoid arthritis (RA), a chronic autoimmune disease, affects around 1% population worldwide, with the life quality of patients severely reduced. In this study, it is intended to explore the role of long non-coding RNA X-inactive specific transcript (lncRNA XIST) in RA and the underlying mechanisms associated with let-7c-5p and signal transducer and activator of transcription 3 (STAT3).

METHODS

LncRNA XIST, let-7c-5p, and STAT3 expressions were determined in RA and normal cartilage tissues, and their relationship was analyzed in osteoblasts. The regulatory effects of lncRNA XIST in RA were investigated when XIST expression was upregulated or downregulated in osteoblasts. TNF-α, IL-2, IL-6, alkaline phosphatase (ALP), osteocalcin, TGF-β1, and IGF1 were measured in vivo in RA rats.

RESULTS

LncRNA XIST and STAT3 were expressed at high levels and let-7c-5p expressed at a low level in RA cartilage tissues. LncRNA XIST silencing or let-7c-5p enhancement led to decreased levels of TNF-α, IL-2, and IL-6, suggestive of suppressed inflammatory response, and increased levels of ALP, osteocalcin, TGF-β1, and IGF-1 as well as reduced damage in cartilage tissues.

CONCLUSION

LncRNA XIST downregulation could promote proliferation and differentiation of osteoblasts in RA, serving as a future therapeutic target for RA.

lncRNAs-mRNAs Co-Expression Network Underlying Childhood B-Cell Acute Lymphoblastic Leukaemia: A Pilot Study

Simple Summary

Acute lymphoblastic leukemia (ALL) is one of the most common childhood cancers. The ALL onset involves abnormal proliferation and arrest of differentiation of B or T cell progenitors. Recently, long non–coding RNAs (lncRNAs) gained great interest in the B–ALL leukemogenesis, however, so far few “omic” studies investigate lncRNAs and protein–coding gene networks. In our retrospective study, we conceived an integrated bioinformatic approach, by using NGS platform, to discover lncRNAs strongly correlated with aberrantly expressed protein–coding genes. We provided dysregulated lncRNA–mRNA pairs potentially underlying B–ALL pathogenesis. Diagnosis incidence peak of ALL appears approximatively between 1 and 19 years old. lncRNAs may be of clinical utility as non–invasive biomarker for B–ALL onset or therapy response in support of precision medicine. The identification of lncRNA as key regulators in B–ALL could lead to the identification of the altered pathways able to sustain the leukemic growth.

Abstract

Long non–coding RNAs (lncRNAs) are emerging as key gene regulators in the pathogenesis and development of various cancers including B lymphoblastic leukaemia (B–ALL). In this pilot study, we used RNA–Seq transcriptomic data for identifying novel lncRNA–mRNA cooperative pairs involved in childhood B–ALL pathogenesis. We conceived a bioinformatic pipeline based on unsupervised PCA feature extraction approach and stringent statistical criteria to extract potential childhood B–ALL lncRNA signatures. We then constructed a co–expression network of the aberrantly expressed lncRNAs (30) and protein–coding genes (754). We cross–validated our in–silico findings on an independent dataset and assessed the expression levels of the most differentially expressed lncRNAs and their co–expressed mRNAs through ex vivo experiments. Using the guilt–by–association approach, we predicted lncRNA functions based on their perfectly co–expressed mRNAs (Spearman’s correlation) that resulted closely disease–associated. We shed light on 24 key lncRNAs and their co–expressed mRNAs which may play an important role in B–ALL pathogenesis. Our results may be of clinical utility for diagnostic and/or prognostic purposes in paediatric B–ALL management.

Aberrantly Expressed lncRNAs and mRNAs of Osteogenically Differentiated Mesenchymal Stem Cells in Ossification of the Posterior Longitudinal Ligament

Ectopic bone formation is the chief characteristic of ossification of the posterior longitudinal ligament (OPLL). Emerging evidence has revealed that long non-coding RNAs (lncRNAs) can regulate the osteogenic differentiation of mesenchymal stem cells (MSCs), which are the main cells responsible for bone formation. However, the role of lncRNAs in the pathogenesis of OPLL remains unclear. In this study, 725 aberrantly expressed lncRNAs and 664 mRNAs in osteogenically differentiated MSCs from OPLL patients (OPLL MSCs) were identified by microarrays and confirmed by qRT-PCR assays. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses showed that the most enriched pathways included the p53, JAK-STAT, and PI3K-Akt signaling pathways. The co-expression network showed the interactions between the aberrantly expressed lncRNAs and mRNAs in OPLL MSCs, and the potential targets and transcription factors of the lncRNAs were predicted. Our research demonstrated the aberrantly expressed lncRNA and mRNA and the potential regulatory networks involved in the ectopic bone formation of OPLL. These findings imply that lncRNAs may play a vital role in OPLL, which provides a new perspective on the pathogenesis of OPLL.

Emerging Roles for Noncoding RNAs in Autoimmune Thyroid Disease

Autoimmune thyroid disease (AITD) is one of the most frequent autoimmune disorders. However, the pathogenesis of AITD has not been fully elucidated. Recently, accumulating evidence has demonstrated that abnormal expression of noncoding RNAs (ncRNAs) is closely related to the etiopathogenesis of AITD. microRNAs (miRNAs), long noncoding RNAs (lncRNAs), and circular RNAs (circRNAs) are 3 major groups of ncRNAs that are attracting increasing attention. Herein, we summarized our present knowledge on the role of miRNAs, lncRNAs, and circRNAs in AITD. This review focused on the importance of ncRNAs in development of the most prevalent AITD, such as Hashimoto disease and Graves' diseases. Altogether, the main purpose of this review is to provide new insights in the pathogenesis of AITD and the possibility of developing novel potential therapeutic targets.

Long Noncoding RNAs and Circular RNAs in Autoimmune Diseases

Immune responses are essential for the clearance of pathogens and the repair of injured tissues; however, if these responses are not properly controlled, autoimmune diseases can occur. Autoimmune diseases (ADs) are a family of disorders characterized by the body's immune response being directed against its own tissues, with consequent chronic inflammation and tissue damage. Despite enormous efforts to identify new drug targets and develop new therapies to prevent and ameliorate AD symptoms, no definitive solutions are available today. Additionally, while substantial progress has been made in drug development for some ADs, most treatments only ameliorate symptoms and, in general, ADs are still incurable. Hundreds of genetic loci have been identified and associated with ADs by genome-wide association studies. However, the whole list of molecular factors that contribute to AD pathogenesis is still unknown. Noncoding (nc)RNAs, such as microRNAs, circular (circ)RNAs, and long noncoding (lnc)RNAs, regulate gene expression at different levels in various diseases, including ADs, and serve as potential drug targets as well as biomarkers for disease progression and response to therapy. In this review, we will focus on the potential roles and genetic regulation of ncRNA in four autoimmune diseases-systemic lupus erythematosus, rheumatoid arthritis, multiple sclerosis, and type 1 diabetes mellitus.

Genetic Architecture Associated With Familial Short Stature

CONTEXT

Human height is an inheritable, polygenic trait under complex and multilocus genetic regulation. Familial short stature (FSS; also called genetic short stature) is the most common type of short stature and is insufficiently known.

OBJECTIVE

To investigate the FSS genetic profile and develop a polygenic risk predisposition score for FSS risk prediction.

DESIGN AND SETTING

The FSS participant group of Han Chinese ancestry was diagnosed by pediatric endocrinologists in Taiwan.

PATIENTS AND INTERVENTIONS

The genetic profiles of 1163 participants with FSS were identified by using a bootstrapping subsampling and genome-wide association studies (GWAS) method.

MAIN OUTCOME MEASURES

Genetic profile, polygenic risk predisposition score for risk prediction.

RESULTS

Ten novel genetic single nucleotide polymorphisms (SNPs) and 9 reported GWAS human height-related SNPs were identified for FSS risk. These 10 novel SNPs served as a polygenic risk predisposition score for FSS risk prediction (area under the curve: 0.940 in the testing group). This FSS polygenic risk predisposition score was also associated with the height reduction regression tendency in the general population.

CONCLUSION

A polygenic risk predisposition score composed of 10 genetic SNPs is useful for FSS risk prediction and the height reduction tendency. Thus, it might contribute to FSS risk in the Han Chinese population from Taiwan.

Lnc-ITSN1-2, Derived From RNA Sequencing, Correlates With Increased Disease Risk, Activity and Promotes CD4+ T Cell Activation, Proliferation and Th1/Th17 Cell Differentiation by Serving as a ceRNA for IL-23R via Sponging miR-125a in Inflammatory Bowel Disease

Background: This study aimed to investigate long-non-coding RNA (lncRNA) expression profiles and the correlation of lnc-ITSN1-2 expression with disease risk, activity and inflammation, and its influence on CD4⁺ T cell activation, proliferation, and differentiation of inflammatory bowel disease (IBD).

Methods: LncRNA expression profiles were detected in intestinal mucosa samples from six IBD patients and six healthy controls (HCs). Intestinal mucosa and PBMC lnc-ITSN1-2, IL-23R, and inflammatory cytokines were measured in 120 IBD patients [60 Crohn's disease (CD) and 60 ulcerative colitis (UC)] and 30 HCs. Effect of lnc-ITSN1-2 on IBD CD4⁺ T cell activation, proliferation, and differentiation was determined and its regulatory interaction with miR-125a and IL-23R was detected.

Results: Three-hundred-and-nine upregulated and 310 downregulated lncRNAs were identified in IBD patients by RNA-Sequencing, which were enriched in regulating immune and inflammation related pathways. Large-sample qPCR validation disclosed that both intestinal mucosa and PBMC lnc-ITSN1-2 expressions were increased in IBD patients compared to HCs, and presented with good predictive values for IBD risk, especially for active disease conditions, and they positively correlated with disease activity, inflammation cytokines, and IL-23R in IBD patients. Lnc-ITSN1-2 was decreased after infliximab treatment in active-CD patients. Furthermore, lnc-ITSN1-2 promoted IBD CD4⁺ T cell activation and proliferation, and stimulated Th1/Th17 cell differentiation. Multiple rescue experiments disclosed that lnc-ITSN1-2 functioned in IBD CD4⁺ T cells via targeting miR-125a, then positively regulating IL-23R. Luciferase Reporter assay observed that lnc-ITSN1-2 bound miR-125a, and miR-125a bound IL-23R.

Conclusion: Lnc-ITSN1-2 correlates with increased disease risk, activity, and inflammatory cytokines of IBD, and promotes IBD CD4⁺ T cell activation, proliferation, and Th1/Th17 cell differentiation by serving as a competing endogenous RNA for IL-23R via sponging miR-125a.

The effects of long non-coding ribonucleic acids on various cellular components in rheumatoid arthritis

RA is a chronic, autoimmune-mediated inflammatory pathology. Long non-coding RNAs (lncRNAs) are a novel group of non-coding RNAs with a length of >200 nucleotides. There are reports emerging that suggest that lncRNAs participate in establishing and sustaining autoimmune diseases, including RA. In this review article, we highlight the functions of lncRNAs in different cell types in RA. Our review indicates that lncRNAs affect various cellular components and are novel candidates that could constitute promising targets for the diagnosis and treatment of RA.

Differential long non-coding RNA expression profiles in the peripheral blood and CD4+ T cells of patients with active rheumatoid arthritis

The human transcriptome is primarily composed of long non-coding RNAs (lncRNAs), which are key regulatory molecules of multiple biological processes. In the present study, the expression profiles of lncRNAs in the peripheral blood and CD4⁺ T cells of patients with active rheumatoid arthritis (RA) were determined. Based on the expression profiles, 493 lncRNAs and 374 mRNAs were identified to be differentially expressed in the peripheral blood of active RA patients and healthy donors. Further verification of lncRNAs was performed using reverse transcription-quantitative (RT-q) PCR analysis of peripheral blood from 5 healthy donors and 5 patients with active RA and 14 additional differentially expressed genes were identified. CD4⁺ T cells in peripheral blood from 12 patients with active RA and 8 healthy donors were isolated using magnetic beads and qPCR was used to assess differentially expressed lncRNAs. The results suggested that 7 lncRNAs were upregulated and 2 were downregulated. The results indicated that these 9 lncRNAs may be involved in the pathogenesis of RA. An increased ratio of Th17: T-regulatory (Treg) cells was also observed. It may be hypothesized that LncRNAs serve important roles in the differentiation of CD4⁺ T cells. Receiver operating characteristic curve analysis suggested that these 9 lncRNAs are of potential clinical diagnostic value for RA. Pearson correlation analysis indicated that the correlation coefficient between Ensembl transcript (ENST)00000569543 and complement C4 was 0.623 (P<0.05), and that between ENST00000420096 and anti-cyclic citrullinated peptide antibody or disease activity evaluation score, the correlation coefficient was 0.662 and 0.605, respectively (P<0.05 for each). In conclusion, the results of the present study suggest a possible role of lncRNAs in the differentiation of CD4⁺ T cells and the pathogenesis of RA, as well as the potential value as diagnostic biomarkers for active RA.

Involvement of long noncoding RNAs in the pathogenesis of autoimmune diseases

Autoimmune diseases are a group of heterogeneous disorders characterized by damage to various organs caused by abnormal innate and adaptive immune responses. The pathogenesis of autoimmune diseases is extremely complicated and has not yet been fully elucidated. Long noncoding RNAs (lncRNAs), which are defined as transcripts containing more than 200 nucleotides with no protein-coding capacity, are emerging as important regulators of gene expression via epigenetic modification, transcriptional regulation and posttranscriptional regulation. Accumulating evidence has demonstrated that lncRNAs play a key role in the regulation of immunological functions and autoimmunity. In this review, we discuss various molecular mechanisms by which lncRNAs regulate gene expression and recent findings regarding the involvement of lncRNAs in many human autoimmune diseases, including rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), idiopathic inflammatory myopathy (IIM), systemic sclerosis (SSc) and Sjögren’s syndrome (pSS).

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lncRNAs are observed to be differentially expressed in various autoimmune diseases.

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lncRNAs are involved in abnormal immune regulation and inflammatory responses in autoimmune diseases, which provides new insight into disease pathogenesis.

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LncRNAs may have the potential of biomarkers for diagnosis and prognosis of autoimmune diseases.

lncRNA CASC2 downregulation participates in rheumatoid arthritis, and CASC2 overexpression promotes the apoptosis of fibroblast‑like synoviocytes by downregulating IL‑17

lncRNA cancer susceptibility candidate 2 (CASC2) is a recently identified oncogenic lncRNA in different types of cancers. Our preliminary microarray data showed that lncRNA CASC2 was downregulated in the plasma of patients with rheumatoid arthritis (RA), indicating the involvement of this lncRNA in RA. In the present study, lncRNA CASC2 and IL-17 in plasma were detected by reverse transcription--quantitative PCR and ELISA, respectively. Diagnostic analyses were performed using receiver operating characteristic curves. Flow cytometry was performed to evaluate cell apoptosis. The effects of lncRNA CASC2 on IL-17 expression were determined via western blotting. lncRNA CASC2 was found to be downregulated, while IL-17 was upregulated in the plasma of RA patients when compared with these levels in the plasma of healthy controls. Plasma levels of lncRNA CASC2 and IL-17 were significantly and inversely correlated in both RA patients and healthy controls. Altered plasma levels of lncRNA CASC2 and IL-17 were able to differentiate RA patients from healthy controls. Overexpression of lncRNA CASC2 promoted, while treatment with IL-17 inhibited the apoptosis of human fibroblast-like synoviocytes (HFLSs) isolated from RA patients. Overexpression of lncRNA CASC2 inhibited IL-17 expression in HFLS, while treatment with IL-17 did not significantly affect the expression of lncRNA CASC2. Therefore, downregulation of lncRNA CASC2 is involved in RA and lncRNA CASC2 overexpression may promote the apoptosis of HFLS by downregulating IL-17.

Epigenetics in rheumatoid arthritis; fibroblast-like synoviocytes as an emerging paradigm in the pathogenesis of the disease

Rheumatoid arthritis (RA) is characterized by immune dysfunctions and chronic inflammation that mainly affects diarthrodial joints. Genetics has long been surveyed in searching for the etiopathogenesis of the disease and partially clarified the conundrums within this context. Epigenetic alterations, such as DNA methylation, histone modifications, and noncoding RNAs, which have been considered to be involved in RA pathogenesis, likely explain the nongenetic risk factors. Epigenetic modifications may influence RA through fibroblast-like synoviocytes (FLSs). It has been shown that FLSs play an essential role in the onset and exacerbation of RA, and therefore, they may illustrate some aspects of RA pathogenesis. These cells exhibit a unique DNA methylation profile in the early stage of the disease that changes with disease progression. Histone acetylation profile in RA FLSs is disrupted through the imbalance of histone acetyltransferases and histone deacetylase activity. Furthermore, dysregulation of microRNAs (miRNAs) is immense. Most of these miRNAs have shown an aberrant expression in FLSs that are involved in proliferation and cytokine production. Besides, dysregulation of long noncoding RNAs in FLSs has been revealed and attributed to RA pathogenesis. Further investigations are needed to get a better view of epigenetic alterations and their interactions. We also discuss the role of these epigenetic alterations in RA pathogenesis and their therapeutic potential.

AA, Lukashev AN. Emerging Concepts and Challenges in Rheumatoid Arthritis Gene Therapy

Rheumatoid arthritis (RA) is a systemic inflammatory joint disease affecting about 1% of the population worldwide. Current treatment approaches do not ensure a cure for every patient. Moreover, classical regimens are based on nontargeted systemic immune suppression and have significant side effects. Biological treatment has advanced considerably but efficacy and specificity issues remain. Gene therapy is one of the potential future directions for RA therapy, which is rapidly developing. Several gene therapy trials done so far have been of moderate success, but experimental and genetics studies have yielded novel targets. As a result, the arsenal of gene therapy tools keeps growing. Currently, both viral and nonviral delivery systems are used for RA therapy. Herein, we review recent approaches for RA gene therapy.

LncRNA PICSAR promotes cell proliferation, migration and invasion of fibroblast-like synoviocytes by sponging miRNA-4701-5p in rheumatoid arthritis

Background

Long non-coding RNAs (lncRNAs) have drawn increasing attention because they play a pivotal role in various types of autoimmune diseases, including rheumatoid arthritis (RA). Fibroblast-like synoviocytes (FLSs), a prominent component of hyperplastic synovial pannus tissue, are the primary effector cells in RA synovial hyperplasia and invasion which can lead to joint destruction. In this study, we investigated whether lncRNAs could act as competing endogenous RNAs to regulate the pathological behaviors of RA-FLSs.

Methods

LncRNA microarray was conducted to establish lncRNA expression profiles in FLSs isolated from RA patients and healthy controls (HCs). Differentially expressed lncRNAs were verified by quantitative real-time PCR (qRT-PCR) on RA-FLSs and synovial fluid. The functional role of lncRNA PICSAR downregulation was evaluated in RA-FLSs. We conducted molecular biological analysis to predict miRNAs which have a potential binding site for PICSAR and further refined the results by qRT-PCR. Luciferase reporter assay was adopted to validate the interaction of lncRNA PICSAR and miR-4701-5p. Western Blot and qPCR were used to identify the target gene and protein. The functional role of miR-4701-5p upregulation was examined in RA-FLSs.

Findings

We identified a long intergenic non-protein-coding RNA162 (LINC00162), also known as lncRNA PICSAR (p38 inhibited cutaneous squamous cell carcinoma associated lincRNA), has significantly higher expression in RA-FLSs and RA synovial fluid. The cell proliferation, migration, invasion and proinflammatory cytokines production of RA-FLSs showed significant alterations after the lncRNA PICSAR suppression. Mechanistically, lncRNA PICSAR functioned through sponging miR-4701-5p in RA-FLSs.

Interpretation

Our results reveal PICSAR may exert an essential role in promoting synovial invasion and joint destruction by sponging miR-4701-5p in RA and that lncRNA PICSAR may act as a biomarker of RA.

Analysis of lncRNA expression profiles by sequencing reveals that lnc-AL928768.3 and lnc-AC091493.1 are novel biomarkers for disease risk and activity of rheumatoid arthritis

BACKGROUND

This study aimed to analyze long non-coding RNA (lncRNA) expression profiles in synovium tissue of patients with RA using RNA sequencing, and to further assess the clinical values of dysregulated lncRNAs in RA diagnosis and monitoring.

METHODS

Thirty patients with RA who underwent knee arthroscopy and 30 controls with knee trauma who underwent surgery were consecutively enrolled and synovium tissue samples of both groups were obtained during surgery. In the exploration stage, lncRNA and mRNA expression profiles in three RA samples and three control samples were detected by RNA sequencing and bioinformatic analyses were then performed. In the validation stage, quantitative polymerase chain reaction (qPCR) was subsequently used to detect expression of five candidate lncRNAs in 30 patients with RA and 30 control patients.

RESULTS

A total of 349 lncRNAs and 1582 mRNAs were upregulated and 806 lncRNAs and 1295 mRNAs were downregulated in patients with RA compared with controls. Enrichment analyses revealed that these dysregulated lncRNAs and mRNAs were mainly involved in regulating immune response, leukocyte migration, complement activation, and B cell receptor signaling pathway. Subsequent qPCR validation discovered that lnc-AL928768.3 (P < 0.001) and lnc-AC091493.1 (P < 0.001) were elevated in patients with RA compared with controls and afford good predictive values for RA risk by receiver operating characteristic (ROC) curve analysis. Additionally, the two lncRNAs were positively associated with C-reactive protein level and disease activity score in 28 joints (ESR) (all P < 0.05).

CONCLUSION

Analysis of lncRNA expression profiles by sequencing reveals that lnc-AL928768.3 and lnc-AC091493.1 are novel biomarkers for RA risk and activity.

LINC00355 Promotes Tumor Progression in HNSCC by Hindering MicroRNA-195-Mediated Suppression of HOXA10 Expression

Emerging evidence suggests that long non-coding RNAs (lncRNAs) are involved in the progression of head and neck squamous cell carcinoma (HNSCC). However, the specific role of LINC00355 in HNSCC remains elusive. Here, we identify the relationship between LINC00355 and the development of HNSCC through the interaction of LINC00355 with microRNA-195 (miR-195), which in turn targets homeoboxA10 (HOXA10). First, we identified differentially expressed lncRNAs and genes related to HNSCC. Next, the interaction among LINC00355, miR-195, and HOXA10 was identified. Subsequently, the expression of LINC00355 and miR-195 was altered to evaluate their effects on viability, invasion, migration, epithelial mesenchymal transition (EMT), and apoptosis of cancer stem cells (CSCs) in HNSCC. Finally, we assessed the ability of LINC00355 to alter tumor growth after HNSCC CSCs were injected into nude mice. Our findings indicate that LINC00355 and HOXA10 were highly expressed in HNSCC, while miR-195 was poorly expressed. CSCs with upregulated aldehyde dehydrogenase 1 (ALDH-1) were sorted. Silencing LINC00355 in these cells led to increased miR-195 expression and a reduction in HOXA10 expression, which inhibited viability, invasion, migration, and EMT and promoted apoptosis of CSCs. Silencing LINC00355 in vivo also led to decreased tumor growth. Our study provides evidence that LINC00355 acts as a miR-195 sponge to promote viability, invasion, migration, and EMT and inhibit apoptosis of CSCs by upregulating HOXA10, suggesting that LINC00355 represents a potential therapeutic target in the treatment of HNSCC.

Long non-coding RNA XIST expression as a prognostic factor in human cancers: A meta-analysis

A large number of literature has shown that high expression of X inactive-specific transcript (XIST) is associated with poor prognosis and metastasis of cancer in patients. However, most of this literature is limited by the small sample sizes and discrete outcomes. Therefore, a meta-analysis was performed to investigate the relation between XIST expression and tumor node metastasis (TNM) stage, lymph node metastasis, distant metastasis, and overall survival of cancer patients. We searched for literature in PubMed, Embase, and Web of Science. The pooled hazard ratios (HRs) or odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to evaluate the association of XIST expression with prognosis and clinicopathological characteristics of cancer patients. Finally, a total of 14 articles involving 1123 patients were included in this meta-analysis. The results suggested that high expression of XIST has a significant relationship with a relatively poor overall survival for patients with malignant tumors (HR 1.82; 95% CI 1.32, 2.52; P = 0.0003). Moreover, high expression of XIST was significantly associated with poor TNM stage (OR 3.64; 95% CI 2.62, 5.07; P < 0.0001), lymph node metastasis (OR 2.39; 95% CI 1.65, 3.46; P < 0.0001) and distant metastasis (OR 2.84; 95% CI 1.90, 4.23; P < 0.0001). In conclusion, high expression of lncRNA XIST may be a predictive factor of poor prognosis in human cancers.

Long Non-coding RNA HIX003209 Promotes Inflammation by Sponging miR-6089 via TLR4/NF-κB Signaling Pathway in Rheumatoid Arthritis

Accumulating studies have suggested that long non-coding RNAs (lncRNAs) have drawn more and more attention in rheumatoid arthritis (RA), which can function as competitive endogenous RNAs (ceRNAs) in inflammation and immune disorders. Previously, we have found that lncRNA HIX003209 is differentially expressed in RA. However, the precise mechanism of lncRNA HIX003209 in RA is still vague. We aim to elucidate the role and its targeted microRNA of lncRNA HIX003209 in RA as ceRNA. Significantly increased expression of lncRNA HIX003209 was observed in the peripheral blood mononuclear cells (PBMCs) from RA cases. It was positively associated with TLR2 and TLR4 in RA. Besides, peptidoglycan (PGN) and lipopolysaccharide (LPS) could enhance the expression of lncRNA HIX003209, which reversely promoted the proliferation and activation of macrophages through IκBα/NF-κB signaling pathway. Moreover, HIX003209 was involved in TLR4-mediated inflammation via targeting miR-6089 in macrophages. LncRNA HIX003209 functions as a ceRNA and exaggerates inflammation by sponging miR-6089 through TLR4/NF-κB pathway in macrophages, which offers promising therapeutic strategies for RA.