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

Identification of key genes and long non‑coding RNA expression profiles in osteoporosis with rheumatoid arthritis based on bioinformatics analysis

BACKGROUND

Although rheumatoid arthritis (RA) is a chronic systemic tissue disease often accompanied by osteoporosis (OP), the molecular mechanisms underlying this association remain unclear. This study aimed to elucidate the pathogenesis of RA and OP by identifying differentially expressed mRNAs (DEmRNAs) and long non-coding RNAs (lncRNAs) using a bioinformatics approach.

METHODS

Expression profiles of individuals diagnosed with OP and RA were retrieved from the Gene Expression Omnibus database. Differential expression analysis was conducted. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes pathway (KEGG) pathway enrichment analyses were performed to gain insights into the functional categories and molecular/biochemical pathways associated with DEmRNAs. We identified the intersection of common DEmRNAs and lncRNAs and constructed a protein-protein interaction (PPI) network. Correlation analysis between the common DEmRNAs and lncRNAs facilitated the construction of a coding-non-coding network. Lastly, serum peripheral blood mononuclear cells (PBMCs) from patients with RA and OP, as well as healthy controls, were obtained for TRAP staining and qRT-PCR to validate the findings obtained from the online dataset assessments.

RESULTS

A total of 28 DEmRNAs and 2 DElncRNAs were identified in individuals with both RA and OP. Chromosomal distribution analysis of the consensus DEmRNAs revealed that chromosome 1 had the highest number of differential expression genes. GO and KEGG analyses indicated that these DEmRNAs were primarily associated with " platelets (PLTs) degranulation", "platelet alpha granules", "platelet activation", "tight junctions" and "leukocyte transendothelial migration", with many genes functionally related to PLTs. In the PPI network, MT-ATP6 and PTGS1 emerged as potential hub genes, with MT-ATP6 originating from mitochondrial DNA. Co-expression analysis identified two key lncRNA-mRNA pairs: RP11 - 815J21.2 with MT - ATP6 and RP11 - 815J21.2 with PTGS1. Experimental validation confirmed significant differential expression of RP11-815J21.2, MT-ATP6 and PTGS1 between the healthy controls and the RA + OP groups. Notably, knockdown of RP11-815J21.2 attenuated TNF + IL-6-induced osteoclastogenesis.

CONCLUSIONS

This study successfully identified shared dysregulated genes and potential therapeutic targets in individuals with RA and OP, highlighting their molecular similarities. These findings provide new insights into the pathogenesis of RA and OP and suggest potential avenues for further research and targeted therapies.

Non-coding RNAs in immunoregulation and autoimmunity: Technological advances and critical limitations

Immune cell function is critically dependent on precise control over transcriptional output from the genome. In this respect, integration of environmental signals that regulate gene expression, specifically by transcription factors, enhancer DNA elements, genome topography and non-coding RNAs (ncRNAs), are key components. The first three have been extensively investigated. Even though non-coding RNAs represent the vast majority of cellular RNA species, this class of RNA remains historically understudied. This is partly because of a lag in technological and bioinformatic innovations specifically capable of identifying and accurately measuring their expression. Nevertheless, recent progress in this domain has enabled a profusion of publications identifying novel sub-types of ncRNAs and studies directly addressing the function of ncRNAs in human health and disease. Many ncRNAs, including circular and enhancer RNAs, have now been demonstrated to play key functions in the regulation of immune cells and to show associations with immune-mediated diseases. Some ncRNAs may function as biomarkers of disease, aiding in diagnostics and in estimating response to treatment, while others may play a direct role in the pathogenesis of disease. Importantly, some are relatively stable and are amenable to therapeutic targeting, for example through gene therapy. Here, we provide an overview of ncRNAs and review technological advances that enable their study and hold substantial promise for the future. We provide context-specific examples by examining the associations of ncRNAs with four prototypical human autoimmune diseases, specifically rheumatoid arthritis, psoriasis, inflammatory bowel disease and multiple sclerosis. We anticipate that the utility and mechanistic roles of these ncRNAs in autoimmunity will be further elucidated in the near future.

Biomarkers (mRNAs and non-coding RNAs) for the diagnosis and prognosis of rheumatoid arthritis

In recent years, diagnostic and therapeutic approaches for rheumatoid arthritis (RA) have continued to improve. However, in the advanced stages of the disease, patients are unable to achieve long-term clinical remission and often suffer from systemic multi-organ damage and severe complications. Patients with RA usually have no overt clinical manifestations in the early stages, and by the time a definitive diagnosis is made, the disease is already at an advanced stage. RA is diagnosed clinically and with laboratory tests, including the blood markers C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) and the autoantibodies rheumatoid factor (RF) and anticitrullinated protein antibodies (ACPA). However, the presence of RF and ACPA autoantibodies is associated with aggravated disease, joint damage, and increased mortality, and these autoantibodies have low specificity and sensitivity. The etiology of RA is unknown, with the pathogenesis involving multiple factors and clinical heterogeneity. The early diagnosis, subtype classification, and prognosis of RA remain challenging, and studies to develop minimally invasive or non-invasive biomarkers in the form of biofluid biopsies are becoming more common. Non-coding RNA (ncRNA) molecules are composed of long non-coding RNAs, small nucleolar RNAs, microRNAs, and circular RNAs, which play an essential role in disease onset and progression and can be used in the early diagnosis and prognosis of RA. In this review of the diagnostic and prognostic approaches to RA disease, we provide an overview of the current knowledge on the subject, focusing on recent advances in mRNA-ncRNA as diagnostic and prognostic biomarkers from the biofluid to the tissue level.

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.

Noncoding RNAs and Virus and Treatment in Allergic Rhinitis

Allergic rhinitis (AR) is a type I hypersensitivity reaction disease caused by inhaled allergens and immunoglobulin E (IgE)-mediated. Noncoding RNA (ncRNA) is an important regulator involved in gene expression and can be detected in the cytoplasm or extracellular fluid, which mainly includes microRNAs (miRNA, length 22-24 nucleotides), long noncoding RNAs (lncRNA, length >200 nucleotides), and circRNAs. LncRNA and miRNA both participate in the regulation of immune function. Some respiratory viral infections can aggravate allergic rhinitis, such as a respiratory syncytial virus (RSV) and human metapneumovirus (hMPV). However, the interaction between viral infection and allergy is complex and the mechanism is still unclear. In this review, we summarized the interactions of noncoding RNAs and viruses in the occurrence and development of AR, along with the treatments focusing on the noncoding RNAs in the past five years.

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.

Dysfunctions, Molecular Mechanisms, and Therapeutic Strategies of Regulatory T Cells in Rheumatoid Arthritis

Regulatory T cells (Tregs) represent a distinct subpopulation of CD4⁺ T lymphocytes that promote immune tolerance and maintain immune system homeostasis. The dysfunction of Tregs is tightly associated with rheumatoid arthritis (RA). Although the complex pathogenic processes of RA remain unclear, studies on Tregs in RA have achieved substantial progress not only in fundamental research but also in clinical application. This review discusses the current knowledge of the characterizations, functions, and molecular mechanisms of Tregs in the pathogenesis of RA, and potential therapies for these disorders are also involved.

LncRNA linc00152/NF-κB feedback loop promotes fibroblast-like synovial cells inflammation in rheumatoid arthritis via regulating miR-103a/TAK1 axis and YY1 expression

INTRODUCTION

Overexpressed inflammatory cytokines are the main factors causing rheumatoid arthritis (RA) tissue damage and pathological deterioration, and lncRNAs has found to beinvolved in some autoinflammatory diseases.

METHODS

We designed this study to investigate the effect of lncRNA linc00152 on rheumatoid arthritis inflammation and explore its molecular mechanism.

RESULT

We found that linc00152 was not only up-regulated in rheumatoid arthritis fibroblast-like synoviocytes (RAFLS), but also stimulated by TNF-α/IL-1β in adose- and time-dependent manner in RAFLS and this expression depends on the NF-κB signaling pathway. Conversely, linc00152 promoted TNF-α/IL-1β expression in RAFLS induced by TNF-α/IL-1β. In addition, we found that linc00152 promoted TAK1 expression by targeting inhibition of miR-103a and activated TAK1-mediated NF-κB pathway. NF-kB indirectly promotes linc00152 expression by promoting the transcription activity of YY1, and YY1 directly promotes linc00152 expression by binding the promoter of linc00152.

CONCLUSION

Our data suggested that the linc00152/NF-κB feedback loop promotes RAFLS inflammation via regulating miR-103a/TAK1 axis and YY1 expression. Thus, linc00152 acts as a switch to control this regulatory circuit and may serve as a diagnostic and therapeutic target for RA treatment.

Non-Coding RNA in Systemic Sclerosis: A Valuable Tool for Translational and Personalized Medicine

Epigenetic factors are heritable and ultimately play a role in modulating gene expression and, thus, in regulating cell functions. Non-coding RNAs have growing recognition as novel biomarkers and crucial regulators of pathological conditions in humans. Their characteristic feature is being transcribed in a tissue-specific pattern. Now, there is emerging evidence that lncRNAs have been identified to be involved in the differentiation of human skin, wound healing, fibrosis, inflammation, and immunological response. Systemic sclerosis (SSc) is a heterogeneous autoimmune disease characterized by fibrosis, vascular abnormalities, and immune system activation. The pathogenesis remains elusive, but clinical manifestations reveal autoimmunity with the presence of specific autoantibodies, activation of innate and adaptive immunity, vascular changes, and active deposition of extracellular matrix components leading to fibrosis. The use of multi-omics studies, including NGS, RNA-seq, or GWAS, has proposed that the non-coding genome may be a significant player in its pathogenesis. Moreover, it may unravel new therapeutic targets in the future. The aim of this review is to show the pathogenic role of long non-coding RNAs in systemic sclerosis. Investigation of these transcripts' functions has the potential to elucidate the molecular pathology of SSc and provide new opportunities for drug-targeted therapy for this disorder.

MicroRNA-26b-5p alleviates murine collagen-induced arthritis by modulating Th17 cell plasticity

Rheumatoid arthritis (RA) is a chronic autoimmune disease, and the abnormal differentiation of IL-17-producing T helper (Th17) cells is an important factor in the pathogenesis. Previous studies have shown that microRNAs (miRNAs, miR) act as key regulators of Th17 cells. However, the effects of miRNAs on Th17 cell differentiation and plasticity in RA are not clear. In this study, not only low miR-26b-5p expression and high IL-17A level were observed in the peripheral blood of RA patients, but also the negative correlation between miR-26b-5p and IL-17A was explored. The changes in collagen-induced arthritis (CIA) mice were consistent with those in RA patients. The results of in vitro experiments showed that miR-26b-5p mainly inhibited the initial differentiation of Th17 cells but did not impact the differentiation of induced-Treg into Th17-like cells. Meanwhile, miR-26b-5p mimics treatment alleviated inflammatory responses and reduced Th17 proportion in CIA mice. These results indicated that miR-26b-5p could alleviate the development of mice CIA by inhibiting the excessive Th17 cells, and that miR-26b-5p could modulate the plasticity of Th17 cell differentiation in RA, mainly block the initial differentiation. This may provide a novel strategy for the clinical treatment of RA.

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.