Inhibition of lncRNA NEAT1 induces dysfunction of fibroblast-like synoviocytes in rheumatoid arthritis via miRNA-338-3p-mediated regulation of glutamine metabolism

Exosomal Osteoclast-Derived miRNA in Rheumatoid Arthritis: From Their Pathogenesis in Bone Erosion to New Therapeutic Approaches

Rheumatoid arthritis (RA) is an autoimmune disease that causes inflammation, pain, and ultimately, bone erosion of the joints. The causes of this disease are multifactorial, including genetic factors, such as the presence of the human leukocyte antigen (HLA)-DRB1*04 variant, alterations in the microbiota, or immune factors including increased cytotoxic T lymphocytes (CTLs), neutrophils, or elevated M1 macrophages which, taken together, produce high levels of pro-inflammatory cytokines. In this review, we focused on the function exerted by osteoclasts on osteoblasts and other osteoclasts by means of the release of exosomal microRNAs (miRNAs). Based on a thorough revision, we classified these molecules into three categories according to their function: osteoclast inhibitors (miR-23a, miR-29b, and miR-214), osteoblast inhibitors (miR-22-3p, miR-26a, miR-27a, miR-29a, miR-125b, and miR-146a), and osteoblast enhancers (miR-20a, miR-34a, miR-96, miR-106a, miR-142, miR-199a, miR-324, and miR-486b). Finally, we analyzed potential therapeutic targets of these exosomal miRNAs, such as the use of antagomiRs, blockmiRs, agomiRs and competitive endogenous RNAs (ceRNAs), which are already being tested in murine and ex vivo models of RA. These strategies might have an important role in reestablishing the regulation of osteoclast and osteoblast differentiation making progress in the development of personalized medicine.

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.

Exploring the effect of LncRNA DANCR to regulate the Keap1-Nrf2/ARE pathway on oxidative stress in rheumatoid arthritis

INTRODUCTION

Aberrant expression of long noncoding RNAs (LncRNAs) can regulate oxidative stress in rheumatoid arthritis (RA). This study focused on investigating the effects of LncRNA differentiation antagonizing nonprotein coding RNA (DANCR) regulation of Keap1-Nrf2/ARE pathway on inflammation and oxidative stress in RA.

METHODS

The levels of LncRNA DANCR/miR-486-3p/Keap1 in peripheral blood of 30 RA groups and 30 normal subjects were examined, and the association of LncRNA DANCR with inflammatory indicators of RA was investigated. We stimulated fibroblast-like synoviocytes (FLS) from RA patients with tumor necrosis factor α and subsequently performed in vitro cellular assays to construct overexpression plasmids and small interfering RNAs of LncRNA DANCR to investigate the relationship between LncRNA DANCR and FLSs viability and migration in RA, as well as the effects on cellular oxidative stress factors and Keap1-Nrf2/ARE pathway; molecular biology analysis was used to predict microRNAs that can bind LncRNA DANCR, and luciferase verified the binding sites of LncRNA DANCR with Keap1 and miR-486-3p; to further refine the gene and protein expression results, we used reverse transcription-quantitative polymerase chain reaction and immunoblotting assays.

RESULTS

In both groups of peripheral blood mononuclear cells, the expression levels of LncRNA DANCR and Keap1 messenger RNA were higher in the RA group than in the normal control group, and the opposite was true for miR-486-3p; LncRNA DANCR was positively correlated with total antioxidant capacity (TAOC), IL6, IL17, malondialdehyde (MDA), but not with IL11, rheumatoid factor, cyclic citrullinated peptide, superoxide dismutase (SOD), with 28-joint disease activity score, reactive oxygen species, C-reactive protein, and erythrocyte sedimentation rate were negatively correlated; overexpression of LncRNA DANCR stimulated the Keap1-Nrf2/ARE pathway, decreased the expression of IL10, SOD, TAOC, and increased the expression levels of MDA, IL11, IL-17, PD-L1, and silencing of LncRNA DANCR was the opposite, but knockdown of miR-486-3p or overexpression of keap1 reversed the expression of the above-mentioned inflammatory and oxidative factors. In addition, pcDNA-DANCR clearly showed stronger cell invasion and migration ability and exacerbated its inflammatory response, which may be related to the regulatory role of miR-486-3p and Keap1-Nrf2/ARE signaling pathway, and we verified their targeting relationship using dual luciferase, showing that DANCR could regulate Keap1-Nrf2/ARE through miR-486-3p modulates the Keap1-Nrf2/ARE pathway and affects inflammatory and oxidative responses in RA patients.

CONCLUSION

The low-expressed LncRNA DANCR may regulate the Keap1-Nrf2/ARE pathway and suppress the inflammatory and oxidative responses in RA patients.

Ligustrazine inhibits inflammatory response of human endometrial stromal cells through the STAT3/IGF2BP1/RELA axis

CONTEXT

Endometriosis (EMs) is a gynecological disorder. Ligustrazine has been reported to exert an anti-inflammatory effect on EMs. However, the underlying mechanisms are not completely understood.

OBJECTIVE

To investigate the effects of ligustrazine on the progression of EMs and the underlying regulatory mechanisms.

MATERIALS AND METHODS

Human endometrial stromal cells (HESCs) were isolated from patients with EMs or control subjects. HESCs were treated with 25, 50, 100, or 200 μM ligustrazine for 1, 3, 6, or 12 h. Western blot and enzyme-linked immunosorbent assays were performed to determine the levels of proteins and inflammatory cytokines, respectively. The binding between STAT3 and insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1) was assessed by chromatin immunoprecipitation and dual-luciferase reporter assays. The relationship between IGF2BP1 and RELA was assessed by RNA immunoprecipitation and RNA pull-down assay.

RESULTS

Phosphorylated STAT3, IGF2BP1, RELA, TNF-α, IL-6, and IL-1β were upregulated in EMs tissues compared with control tissues (by 1.79-, 2.55-, 1.58-, 3.01-, 2.55-, and 3.34-fold, respectively). Ligustrazine inhibited the expression of p-STAT3, IGF2BP1, RELA, IL-6, TNF-α, and IL-1β. Overexpression of STAT3 promoted RELA-mediated inflammatory responses, while ligustrazine (100 µM) notably reversed this phenomenon. Ligustrazine also alleviated RELA-induced inflammation via downregulating IGF2BP1. STAT3 bound to the promoter of IGF2BP1, and IGF2BP1 bound to the RELA mRNA.

DISCUSSION AND CONCLUSION

Ligustrazine inhibited inflammation in EMs via regulating the STAT3/IGF2BP1/RELA axis. These findings propose a new agent against EMs and support the development of ligustrazine-based treatment strategies for EMs.

Long non-coding RNAs and rheumatoid arthritis: Pathogenesis and clinical implications

Long non-coding RNAs (lncRNAs) are a class of noncoding RNAs with a length larger than 200 nucleotides that participate in various diseases and biological processes as they can control gene expression by different mechanisms. Rheumatoid arthritis (RA) is an inflammatory autoimmune disorder characterized by symmetrical destructive destruction of distal joints as well as extra-articular involvement. Different studies have documented and proven the abnormal expression of lncRNAs in RA patients. Various lncRNAs have proven potential as biomarkers and targets for diagnosing, prognosis and treating RA. This review will focus on RA pathogenesis, clinical implications, and related lncRNA expressions that help to identify new biomarkers and treatment targets.

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.