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

Biological functions and affected signaling pathways by Long Non-Coding RNAs in the immune system

Recently, the various regulative functions of long non-coding RNAs (LncRNAs) have been well determined. Recently, the vital role of LncRNAs as gene regulators has been identified in the immune system, especially in the inflammatory response. All cells of the immune system are governed by a complex and ever-changing gene expression program that is regulated through both transcriptional and post-transcriptional processes. LncRNAs regulate gene expression within the cell nucleus by influencing transcription or through post-transcriptional processes that affect the splicing, stability, or translation of messenger RNAs (mRNAs). Recent studies in immunology have revealed substantial alterations in the expression of lncRNAs during the activation of the innate immune system as well as the development, differentiation, and activation of T cells. These lncRNAs regulate key aspects of immune function, including the manufacturing of inflammatory molecules, cellular distinction, and cell movement. They do this by modulating protein-protein interactions or through base pairing with RNA and DNA. Here we review the current understanding of the mechanism of action of lncRNAs as novel immune-related regulators and their impact on physiological and pathological processes related to the immune system, including autoimmune diseases. We also highlight the emerging pattern of gene expression control in important research areas at the intersection between immunology and lncRNA biology.

Identification of serum exosomal lncRNAs and their potential regulation of characteristic genes of fibroblast-like synoviocytes in rheumatoid arthritis

Rheumatoid arthritis (RA) is a common autoimmune disease whose pathogenesis is poorly understand. Gaps in laboratory biomarkers cause a lack of clinically available strategies for the early diagnosis and treatment of RA. This study aims to identify serum exosomal lncRNAs as promising biomarkers and to unravel potential mechanisms by which they affect characteristic genes of fibroblast-like synoviocytes (FLSs) to induce RA malignant properties. RNA sequencing datasets of serum exosomes (GSE271161 and PRJNA911001) and FLSs (GSE103578, GSE122616, GSE128813, GSE181614 and GSE83147) were purposively mined. Visualization and functional enrichment of differentially expressed (DE) lncRNAs/protein-coding genes, screening of significant lncRNAs, and construction of competing endogenous RNAs (ceRNAs) and protein-protein interaction (PPI) network were carried out. Quantitative real-time PCR, receiver operating characteristic curve (ROC) and correlation analysis were conducted on the validation cohort. As a result, we screened a total of 131 serum exosomal DElncRNAs and 125 FLSs DEmRNAs, which were predominantly enriched in the proliferative, inflammatory and metabolic pathways. In-depth learning of DElncRNAs expression profiles was performed to identify models with better performance and lncRNAs with higher importance scores using 4 machine learning algorithms (SVM, KNN, RF, Logit), which led to the establishment of ceRNAs network linking serum exosomal lncRNAs and characteristic genes of FLSs. In short, we proposed that 4 RA-representative serum exosomal lncRNAs (DLEU2, FAM13A-AS1, MEG3 and SNHG15) may be applied as valuable indicators for laboratory tests, and their-mediated intercellular communication and ceRNAs network may regulate the characteristic genes of FLSs, thereby generating malignant phenotypes and adaptive synovial microenvironment in RA.

Ketogenic diet modulates immune cell transcriptional landscape and ameliorates experimental autoimmune uveitis in mice

BACKGROUND

Uveitis manifests as immune-mediated inflammatory disorders within the eye, posing a serious threat to vision. The ketogenic diet (KD) has emerged as a promising dietary intervention, yet its impact on the immune microenvironments and role in uveitis remains unclear.

METHODS

Utilizing single-cell RNA sequencing (scRNA-seq) data from lymph node and retina of mice, we conduct a comprehensive investigation into the effects of KD on immune microenvironments. Flow cytometry is conducted to verify the potential mechanisms.

RESULTS

This study demonstrates that KD alters the composition and function of immune profiles. Specifically, KD promotes the differentiation of Treg cells and elevates its proportion in heathy mice. In response to experimental autoimmune uveitis challenges, KD alleviates the inflammatory symptoms, lowers CD4+ T cell pathogenicity, and corrects the Th17/Treg imbalance. Additionally, KD decreases the proportion of Th17 cell and increases Treg cells in the retina. Analysis of combined retinal and CDLN immune cells reveals that retinal immune cells, particularly CD4+ T cells, exhibit heightened inflammatory responses, which KD partially reverses.

CONCLUSIONS

The KD induces inhibitory structural and functional alterations in immune cells from lymph nodes to retina, suggesting its potential as a therapy for uveitis.

The Challenges of Local Intra-Articular Therapy

Fibroblast-like synoviocytes (FLSs) are among the main disease-driving players in most cases of monoarthritis (MonoA), oligoarthritis, and polyarthritis. In this review, we look at the characteristics and therapeutic challenges at the onset of arthritis and during follow-up management. In some cases, these forms of arthritis develop into autoimmune polyarthritis, such as rheumatoid arthritis (RA), whereas local eradication of the RA synovium could still be combined with systemic treatment using immunosuppressive agents. Currently, the outcomes of local synovectomies are well studied; however, there is still a lack of a comprehensive analysis of current local intra-articular treatments highlighting their advantages and disadvantages. Therefore, the aim of this study is to review local intra-articular therapy strategies. According to publications from the last decade on clinical studies focused on intra-articular treatment with anti-inflammatory molecules, a range of novel slow-acting forms of steroidal drugs for the local treatment of synovitis have been investigated. As pain is an essential symptom, caused by both inflammation and cartilage damage, various molecules acting on pain receptors are being investigated in clinical trials as potential targets for local intra-articular treatment. We also overview the new targets for local treatment, including surface markers and intracellular proteins, non-coding ribonucleic acids (RNAs), etc.

The role of non-coding RNAs in fibroblast-like synoviocytes in rheumatoid arthritis

Rheumatoid arthritis (RA) is an inflammatory autoimmune disease characterized by synovial hyperplasia, and fibroblast-like synoviocytes (FLSs) constitute the majority of cells in the synovial tissue, playing a crucial role in the onset of RA. Dysregulation of FLSs function is a critical strategy in treating joint damage associated with RA. Non-coding RNAs, a class of RNA molecules that do not encode proteins, participate in the development of various diseases. This article aims to review the progress in the study of long non-coding RNAs, microRNAs, and circular RNAs in FLSs. Non-coding RNAs are involved in the pathogenesis of RA, directly or indirectly regulating FLSs' proliferation, migration, invasion, apoptosis, and inflammatory responses. Furthermore, non-coding RNAs also influence DNA methylation and osteogenic differentiation in FLSs. Therefore, non-coding RNAs hold promise as biomarkers for diagnosing RA. Targeting non-coding RNAs in FLSs locally represents a potential strategy for future therapies in RA.

Generation of cytotoxic aptamers specifically targeting fibroblast-like synoviocytes by CSCT-SELEX for treatment of rheumatoid arthritis

OBJECTIVES

Rheumatoid arthritis (RA) is an autoimmune disease characterised by aggressive fibroblast-like synoviocytes (FLSs). Very few RA patients-derived FLSs (RA-FLSs)-specific surface signatures have been identified, and there is currently no approved targeted therapy for RA-FLSs. This study aimed to screen therapeutic aptamers with cell-targeting and cytotoxic properties against RA-FLSs and to uncover the molecular targets and mechanism of action of the screened aptamers.

METHODS

We developed a cell-specific and cytotoxic systematic evolution of ligands by exponential enrichment (CSCT-SELEX) method to screen the therapeutic aptamers without prior knowledge of the surface signatures of RA-FLSs. The molecular targets and mechanisms of action of the screened aptamers were determined by pull-down assays and RNA sequencing. The therapeutic efficacy of the screened aptamers was examined in arthritic mouse models.

RESULTS

We obtained an aptamer SAPT8 that selectively recognised and killed RA-FLSs. The molecular target of SAPT8 was nucleolin (NCL), a shuttling protein overexpressed on the surface and involved in the tumor-like transformation of RA-FLSs. Mechanistically, SAPT8 interacted with the surface NCL and was internalised to achieve lysosomal degradation of NCL, leading to the upregulation of proapoptotic p53 and downregulation of antiapoptotic B-cell lymphoma 2 (Bcl-2) in RA-FLSs. When administrated systemically to arthritic mice, SAPT8 accumulated in the inflamed FLSs of joints. SAPT8 monotherapy or its combination with tumour necrosis factor (TNF)-targeted biologics was shown to relieve arthritis in mouse models.

CONCLUSIONS

CSCT-SELEX could be a promising strategy for developing cell-targeting and cytotoxic aptamers. SAPT8 aptamer selectively ablates RA-FLSs via modulating NCL-p53/Bcl-2 signalling, representing a potential alternative or complementary therapy for RA.

Small molecule and big function: MicroRNA-mediated apoptosis in rheumatoid arthritis

Rheumatoid arthritis (RA) is a common autoimmune condition and chronic inflammatory disease, mostly affecting synovial joints. The complex pathogenesis of RA is supportive of high morbidity, disability, and mortality rates. Pathological changes a common characteristic in RA synovial tissue is attributed to the inadequacy of apoptotic pathways. In that regard, apoptotic pathways have been the center of attention in RA therapeutic approaches. As the regulators in the complex network of apoptosis, microRNAs (miRNAs) are found to be vital modulators in both intrinsic and extrinsic pathways through altering their regulatory genes. Indeed, miRNA, a member of the family of non-coding RNAs, are found to be an important player in not even apoptosis, but proliferation, gene expression, signaling pathways, and angiogenesis. Aberrant expression of miRNAs is implicated in attenuation and/or intensification of various apoptosis routes, resulting in culmination of human diseases including RA. Considering the need for more studies focused on the underlying mechanisms of RA in order to elevate the unsatisfactory clinical treatments, this study is aimed to delineate the importance of apoptosis in the pathophysiology of this disease. As well, this review is focused on the critical role of miRNAs in inducing or inhibiting apoptosis of RA-synovial fibroblasts and fibroblast-like synoviocytes and how this mechanism can be exerted for therapeutic purposes for RA.

Diagnostic and Therapeutic Roles of Extracellular Vesicles and Their Enwrapped ncRNAs in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a systemic inflammatory disease whose precise pathogenesis remains mysterious. The involvement of epigenetic regulation in the pathogenesis of RA is one of the most anticipated findings, among which non-coding RNAs (ncRNAs) hold great application promise as diagnostic and therapeutic biomarkers for RA. Extracellular vesicles (EVs) are a heterogeneous group of nano-sized, membrane-enclosed vesicles that mediate intercellular communication and substance exchange, especially the transfer of ncRNAs from donor cells, thereby regulating the functional activities and biological processes of recipient cells. In light of the significant correlation between EVs, ncRNAs, and RA, we first documented expression levels of EVs and their-encapsulated ncRNAs in RA individuals, and methodically discussed their-implicated signaling pathways and phenotypic changes. The last but not least, we paied special attention to the therapeutic benefits of gene therapy reagents specifically imitating or silencing candidate ncRNAs with exosomes as carriers on RA animal models, and briefly highlighted their clinical application advantage and foreground. In conclusion, the present review may be conducive to a deeper comprehension of the diagnostic and therapeutic roles of EVs-enwrapped ncRNAs in RA, with special emphasis on exosomal ncRNAs, which may offer hints for the monitoring and treatment of RA.

Jianpi Qingre Tongluo Decoction exerted an anti-inflammatory effect on AS by inhibiting the NONHSAT227927.1/JAK2/STAT3 axis

Purpose

This study aims to determine whether Jianpi Qingre Tongluo Decoction (JQP) alleviates ankylosing spondylitis (AS) inflammation via the NONHSAT227927.1/JAK2/STAT3 axis.

Methods

The effect of JQP on immune-inflammatory indicators in AS patients was explored through a combination of data mining, association rule analysis, and random walk model evaluation. Subsequently, network pharmacology and molecular docking were performed to screen out the potential signaling pathway. ELISA, PCR and wb were used to evaluate the effect of JQP on AS-FLS activity and inflammatory factors. The role of NONHSAT227927.1/JAK2/STAT3 combination in inflammation was studied by editing NONHSAT227927.1 and adding the JAK2/STAT3 inhibitor AG490. Involvement of the JAK2/STAT3 pathway was detected by PCR, WB, or immunofluorescence analysis.

Results

Retrospective data mining results show that JQP can effectively reduce the immune inflammatory response in AS patients. Through network pharmacology and molecular docking, it is speculated that JQP exerts its effect on AS through the JAK2/STAT3 pathway. Overexpression of NONHSAT227927.1 activated the JAK2/STAT3 pathway and promoted the expression of inflammatory factors, while serum containing JQP reversed the effects of NONHSAT227927.1 overexpression. NONHSAT227927.1 silencing inhibits the proliferation of AS-FLSs, inhibits the levels of inflammatory factors, and reduces the expression of JAK2/STAT3 protein. After adding the pathway blocker AG490, it was observed that the cell viability of AS-FLSs was reduced by inflammatory factors and the levels of JAK2/STAT3 were inhibited. , and overexpression of NONHSAT227927.1 can reverse this trend.

Conclusions

JQP exerted an anti-inflammatory effect on AS by inhibiting the NONHSAT227927.1/JAK2/STAT3 axis.

Serum exosomes lncRNAs: TCONS_I2_00013502 and ENST00000363624 are new diagnostic markers for rheumatoid arthritis

The lack of diagnostic markers limits the window of effectiveness for rheumatoid arthritis (RA) therapies. Here, we isolated exosomes of serum samples from four distinct groups RA patients, according to disease activity and with/without medication. Then, total RNA of exosomes was extracted for whole-transcriptome sequencing. Focusing on lncRNA sequencing, gene ontology (GO) and kyoto encyclopedia of genes and genomes (KEGG) pathway enrichment analyses were performed. We found that the number of upregulated lncRNAs were significantly higher than that of downregulated lncRNAs in each four RA groups. And most importantly, we identified two specific lncRNAs from differentially expressed lncRNAs, TCONS_I2_00013502 (up-regulated) and ENST00000363624 (down-regulated) in RA. Receiver Operating Characteristic (ROC) curve analysis showed that the two lncRNAs were promising biomarkers for RA diagnosis. These findings highlight lncRNAs of the serum exosome are important biomarkers and provide application potential for diagnosis of RA.

Unveiling Novel Drug Targets and Emerging Therapies for Rheumatoid Arthritis: A Comprehensive Review

Rheumatoid arthritis (RA) is a chronic debilitating autoimmune disease, that causes joint damage, deformities, and decreased functionality. In addition, RA can also impact organs like the skin, lungs, eyes, and blood vessels. This autoimmune condition arises when the immune system erroneously targets the joint synovial membrane, resulting in synovitis, pannus formation, and cartilage damage. RA treatment is often holistic, integrating medication, physical therapy, and lifestyle modifications. Its main objective is to achieve remission or low disease activity by utilizing a "treat-to-target" approach that optimizes drug usage and dose adjustments based on clinical response and disease activity markers. The primary RA treatment uses disease-modifying antirheumatic drugs (DMARDs) that help to interrupt the inflammatory process. When there is an inadequate response, a combination of biologicals and DMARDs is recommended. Biological therapies target inflammatory pathways and have shown promising results in managing RA symptoms. Close monitoring for adverse effects and disease progression is critical to ensure optimal treatment outcomes. A deeper understanding of the pathways and mechanisms will allow new treatment strategies that minimize adverse effects and maintain quality of life. This review discusses the potential targets that can be used for designing and implementing precision medicine in RA treatment, spotlighting the latest breakthroughs in biologics, JAK inhibitors, IL-6 receptor antagonists, TNF blockers, and disease-modifying noncoding RNAs.

Small-molecule targeting PKM2 provides a molecular basis of lactylation-dependent fibroblast-like synoviocytes proliferation inhibition against rheumatoid arthritis

Fibroblast-like synoviocytes (FLS) play an important role in rheumatoid arthritis (RA)-related swelling and bone damage. Therefore, novel targets for RA therapy in FLS are urgently discovered for improving pathologic phenomenon, especially joint damage and dyskinesia. Here, we suggested that pyruvate kinase M2 (PKM2) in FLS represented a pharmacological target for RA treatment by antimalarial drug artemisinin (ART). We demonstrated that ART selectively inhibited human RA-FLS and rat collagen-induced arthritis (CIA)-FLS proliferation and migration without observed toxic effects. In particular, the identification of targets revealed that PKM2 played a crucial role as a primary regulator of the cell cycle, leading to the heightened proliferation of RA-FLS. ART exhibited a direct interaction with PKM2, resulting in an allosteric modulation that enhances the lactylation modification of PKM2. This interaction further promoted the binding of p300, ultimately preventing the nuclear translocation of PKM2 and inducing cell cycle arrest at the S phase. In vivo, ART obviously suppressed RA-mediated synovial hyperplasia, bone damage and inflammatory response to further improve motor behavior in CIA-rats. Taken together, these findings indicate that directing interventions towards PKM2 in FLS could offer a hopeful avenue for pharmaceutical treatments of RA through the regulation of cell cycle via PKM2 lactylation.

Gut microbial metabolite targets HDAC3-FOXK1-interferon axis in fibroblast-like synoviocytes to ameliorate rheumatoid arthritis

Rheumatoid arthritis (RA) is an autoimmune disease. Early studies hold an opinion that gut microbiota is environmentally acquired and associated with RA susceptibility. However, accumulating evidence demonstrates that genetics also shape the gut microbiota. It is known that some strains of inbred laboratory mice are highly susceptible to collagen-induced arthritis (CIA), while the others are resistant to CIA. Here, we show that transplantation of fecal microbiota of CIA-resistant C57BL/6J mice to CIA-susceptible DBA/1J mice confer CIA resistance in DBA/1J mice. C57BL/6J mice and healthy human individuals have enriched B. fragilis than DBA/1J mice and RA patients. Transplantation of B. fragilis prevents CIA in DBA/1J mice. We identify that B. fragilis mainly produces propionate and C57BL/6J mice and healthy human individuals have higher level of propionate. Fibroblast-like synoviocytes (FLSs) in RA are activated to undergo tumor-like transformation. Propionate disrupts HDAC3-FOXK1 interaction to increase acetylation of FOXK1, resulting in reduced FOXK1 stability, blocked interferon signaling and deactivation of RA-FLSs. We treat CIA mice with propionate and show that propionate attenuates CIA. Moreover, a combination of propionate with anti-TNF etanercept synergistically relieves CIA. These results suggest that B. fragilis or propionate could be an alternative or complementary approach to the current therapies.

Sulfasalazine promotes ferroptosis through AKT-ERK1/2 and P53-SLC7A11 in rheumatoid arthritis

OBJECTIVE

Ferroptosis has been reported to play a role in rheumatoid arthritis (RA). Sulfasalazine, a common clinical treatment for ankylosing spondylitis, also exerts pathological influence on the progression of rheumatoid arthritis including the induced ferroptosis of fibroblast-like synoviocytes (FLSs), which result in the perturbated downstream signaling and the development of RA. The aim of this study was to investigate the underlying mechanism so as to provide novel insight for the treatment of RA.

METHODS

CCK-8 and Western blotting were used to assess the effect of sulfasalazine on FLSs. A collagen-induced arthritis mouse model was constructed by the injection of collagen and Freund's adjuvant, and then, mice were treated with sulfasalazine from day 21 after modeling. The synovium was extracted and ferroptosis was assessed by Western blotting and immunofluorescence staining.

RESULTS

The results revealed that sulfasalazine promotes ferroptosis. Compared with the control group, the expression levels of ferroptosis-related proteins such as glutathione peroxidase 4, ferritin heavy chain 1, and solute carrier family 7, member 11 (SLC7A11) were lower in the experimental group. Furthermore, deferoxamine inhibited ferroptosis induced by sulfasalazine. Sulfasalazine-promoted ferroptosis was related to a decrease in ERK1/2 and the increase of P53.

CONCLUSIONS

Sulfasalazine promoted ferroptosis of FLSs in rheumatoid arthritis, and the PI3K-AKT-ERK1/2 pathway and P53-SLC7A11 pathway play an important role in this process.

LncRNA expression profiling in exosomes derived from synovial fluid of patients with rheumatoid arthritis

OBJECTIVE

To identify the long non-coding RNA (lncRNA) expression profiling in exosomes derived from synovial fluid of rheumatoid arthritis (RA) patients, and carry out bioinformatics analysis on target genes of differentially expressed lncRNAs.

METHODS

Exosomes were isolated from synovial fluid via ultracentrifugation. RNAs were extracted from exosomes by using HiPure Liquid RNA/miRNA kits, followed by lncRNA sequencing. Differentially expressed lncRNAs in RA were screened, and bioinformatics analysis of their target genes was carried out. qRT-PCR was used to verify the lncRNA expression levels.

RESULTS

Compared with osteoarthritis (OA), 347 lncRNAs were found differentially expressed in RA. Compared with gout, 805 lncRNAs were found differentially expressed in RA. Compared with both OA and gout, 85 lncRNAs were found specially expressed in RA (65 were upregulated (including ENST00000433825.1)). Functional analysis of target genes of the specially expressed lncRNAs revealed significant enrichment of "autophagy" and "mTOR signaling pathway". The qRT-PCR results indicated that ENST00000433825.1 was highly expressed in RA, compared with both OA and gout (P < 0.05), which matched the lncRNA sequencing results. Correlation analysis showed that the level of ENST00000433825.1 in RA patients was significantly and positively correlated with the level of C-reactive protein (CRP) (P < 0.001).

CONCLUSIONS

The lncRNA expression profiling in exosomes derived from synovial fluid of RA was significantly different from OA and gout. ENST00000433825.1 was highly and uniquely expressed in RA and significantly and positively correlated with CRP, which might provide a diagnostic and therapeutic biomarker for RA.

Bridging autoimmunity and epigenetics: The influence of lncRNA MALAT1

Autoimmune disorders represent a heterogeneous spectrum of conditions defined by an immune system's atypical reactivity against endogenous constituents. In the complex anatomy of autoimmune pathogenesis, lncRNAs have appeared as pivotal arbiters orchestrating the mechanisms of ailment initiation, immune cascades, and transcriptional modulation. One such lncRNA, MALAT1, has garnered attention for its potential association with the aetiology of several autoimmune diseases. MALAT1 has been shown to influence a wide spectrum of cellular processes, which include cell multiplication and specialization, as well as apoptosis and inflammation. In autoimmune diseases, MALAT1 exhibits both disease-specific and shared patterns of dysregulation, often correlating with disease severity. The molecular mechanisms underlying MALAT1's impact on autoimmune disorders include epigenetic modifications, alternative splicing, and modulation of gene expression networks. Additionally, MALAT1's intricate interactions with microRNAs, other lncRNAs, and protein-coding genes further underscore its role in immune regulation and autoimmune disease progression. Understanding the contribution of MALAT1 in autoimmune pathogenesis across different diseases could offer valuable insights into shared pathways, thereby clearing a path for the creation of innovative and enhanced therapeutic approaches to address these complex disorders. This review aims to elucidate the complex role of MALAT1 in autoimmune disorders, encompassing rheumatoid arthritis, multiple sclerosis, inflammatory bowel disease (Crohn's disease and ulcerative colitis), type 1 diabetes, systemic lupus erythematosus, and psoriasis. Furthermore, it discusses the potential of MALAT1 as a diagnostic biomarker, therapeutic target, and prognostic indicator.

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.

Clinical significance of long non-coding RNA NORAD in rheumatoid arthritis

BACKGROUND

Rheumatoid arthritis (RA) is a chronic autoimmune disease that may cause joint deformities and seriously affect the normal life of the patients. In order to enable patients to receive timely attention and treatment, this study developed new diagnostic markers by exploring the expression and molecular mechanism of the long non-coding RNA NORAD (NORAD) in RA.

METHODS

Participants including 77 RA patients and 52 healthy persons were enrolled, and the corresponding clinical data and serum samples were obtained. The NORAD and miR-204-5p expression were detected by real-time fluorescence quantitative polymerase chain reaction (RT-qPCR). The content of inflammatory cytokines (IL-6, TNF-α) were determined through enzyme-linked immunosorbent assay (ELISA). Luciferase activity reporter assay demonstrated the association between NORAD and miR-204-5p. In addition, receiver operating characteristic (ROC) curve was used to evaluate the diagnostic efficacy of NORAD, and Pearson's correlation analysis was applied for the correlation analysis.

RESULTS

NORAD was enriched in RA serum with high diagnostic value. Simultaneously, IL-6 and TNF-α levels were also upregulated (P < 0.001). The C-reactive protein (CRP), rheumatoid factor (RF), erythrocyte sedimentation rate (ESR) and anti-cyclic citrullinated peptide antibody (Anti-CCP) levels in RA patients were generally elevated (P < 0.001). NORAD was positively correlated with the levels of clinical indicators and inflammatory factors (P < 0.0001). Mechanistically, NORAD may affect the progression of RA by targeting and negatively regulating miR-204-5p.

CONCLUSIONS

There is a correlation between NORAD and the processes of RA, and NORAD has the potential to predict and diagnose the occurrence of RA.

LncRNA SNHG8 upregulates MUC5B to induce idiopathic pulmonary fibrosis progression by targeting miR-4701-5p

Long noncoding RNAs (lncRNAs) play a critical role in idiopathic pulmonary fibrosis (IPF); however, the underlying molecular mechanisms are unclear. Our study demonstrated that lncRNA small nucleolar RNA host gene 8 (SNHG8) was increased in bleomycin (BLM)-induced A549 cells. LncRNA SNHG8 overexpression further elevated fibrosis-related factors monocyte chemotactic protein 1 (MCP1), CC motif chemokine ligand 18 (CCL18), and α-smooth muscle actin (α-SMA), as well as increased collagen type I alpha-1 chain (COL1A1) and collagen type III alpha-1 chain (COL3A1). Meanwhile, lncRNA SNHG8 knockdown exhibited an opposite role in reducing BLM-induced pulmonary fibrosis. With regard to the mechanism, SNHG8 was then revealed to act as a competing endogenous RNA (ceRNA) for microRNA (miR)-4701-5p in regulating Mucin 5B (MUC5B) expression. Furthermore, the interactions between SNHG8 and miR-4701-5p, between miR-4701-5p and MUC5B, and between SNHG8 and MUC5B on the influence of fibrosis-related indicators were confirmed, respectively. In addition, SNHG8 overexpression enhanced the levels of transforming growth factor (TGF)-β1 and phosphorylation Smad2/3 (p-Smad2/3), which was suppressed by SNHG8 knockdown in BLM-induced A549 cells. Moreover, miR-4701-5p inhibitor-induced elevation of TGF-β1 and p-Smad2/3 was significantly suppressed by SNHG8 knockdown. In conclusion, SNHG8 knockdown attenuated pulmonary fibrosis progression by regulating miR-4701-5p/MUC5B axis, which might be associated with the modulation of TGF-β1/Smad2/3 signaling. These findings reveal that lncRNA SNHG8 may become a potential target for the treatment of IPF.

Macrophage extracellular traps promote tumor-like biologic behaviors of fibroblast-like synoviocytes through cGAS-mediated PI3K/Akt signaling pathway in patients with rheumatoid arthritis

Rheumatoid arthritis is an autoimmune disease characterized by synovium hyperplasia and bone destruction. Macrophage extracellular traps are released from macrophages under various stimuli and may generate stable autoantigen-DNA complexes, as well as aggravate autoantibody generation and autoimmune responses. We aimed to investigate the role of macrophage extracellular traps on the biologic behaviors of rheumatoid arthritis fibroblast-like synoviocytes. Synovial tissues and fibroblast-like synoviocytes were obtained from patients with rheumatoid arthritis. Extracellular traps in synovium and synovial fluids were detected by immunofluorescence, immunohistochemistry, and SYTOX Green staining. Cell viability, migration, invasion, and cytokine expression of rheumatoid arthritis fibroblast-like synoviocytes were assessed by CCK-8, wound-healing assay, Transwell assays, and quantitative real-time polymerase chain reaction, respectively. RNA sequencing analysis was performed to explore the underlying mechanism, and Western blot was used to validate the active signaling pathways. We found that extracellular trap formation was abundant in rheumatoid arthritis and positively correlated to anti-CCP. Rheumatoid arthritis fibroblast-like synoviocytes stimulated with purified macrophage extracellular traps demonstrated the obvious promotion in tumor-like biologic behaviors. The DNA sensor cGAS in rheumatoid arthritis fibroblast-like synoviocytes was activated after macrophage extracellular trap stimuli. RNA sequencing revealed that differential genes were significantly enriched in the PI3K/Akt signaling pathway, and cGAS inhibitor RU.521 effectively reversed the promotion of tumor-like biologic behaviors in macrophage extracellular trap-treated rheumatoid arthritis fibroblast-like synoviocytes and downregulated the PI3K/Akt activation. In summary, our study demonstrates that macrophage extracellular traps promote the pathogenically biological behaviors of rheumatoid arthritis fibroblast-like synoviocytes through cGAS-mediated activation of the PI3K/Akt signaling pathway. These findings provide a novel insight into the pathogenesis of rheumatoid arthritis and the mechanisms of macrophages in modulating rheumatoid arthritis fibroblast-like synoviocyte tumor-like behaviors.

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.

Analysis of lncRNAs profiles associated with ferroptosis can predict prognosis and immune landscape and drug sensitivity in patients with clear cell renal cell carcinoma

Ferroptosis is a novel kind of iron- and reactive oxygen-induced cell death, investigation into ferroptosis-associated long noncoding RNAs (FALs) in clear cell renal cell carcinoma (ccRCC) is scarce. The goal of the research was to look at FALs' possible predictive significance, as well as their interaction with the immune microenvironment and therapeutic responsiveness of ccRCC. The Cancer Genome Atlas database was employed to retrieve RNA sequencing data from 530 individuals with ccRCC. Patients with ccRCC were randomly assigned to one of two groups: training or testing. Pearson's correlation analysis through the identified ferroptosis-related genes was implemented to screen for FALs. Finally, a FALs signature composed of eight lncRNAs was discovered for predicting survival outcomes in ccRCC patients. ccRCC patients in the training, testing, and overall cohorts were separated into low-risk and high-risk groups based on their risk score. The FALs signature was identified to be an independent factor for overall survival in the multivariate Cox analysis (hazard ratio = 1.013, 95% confidence interval = 1.008-1.018, p < 0.001). A clinically prognostic nomogram was created depending on the FALs signature and clinical characteristics. The nomogram provides greater clinical practicability and may reliably estimate patients' overall survival. The FALs signature may additionally precisely represent ccRCC's immunological environment, immunotherapy reaction, and drug sensitivity. The eight FALs and their signature provide precise and reliable methods for evaluating the clinical effects of in ccRCC patients, and they could be biological markers and targets for therapy.

LncRNAs associated with oxidative stress in diabetic wound healing: Regulatory mechanisms and application prospects

Diabetes is a group of chronic diseases with blood glucose imbalance, and long-term hyperglycaemia causes sustained damage to various organs of the body, resulting in vascular lesions, neuropathy and impaired wound healing. Diabetic wound formation involves a variety of complex mechanisms, and they are characterized by a persistent chronic inflammatory response, degradation of angiogenesis and imbalance of extracellular matrix regulation, all of which are related to oxidative stress. Additionally, repair and healing of diabetic wounds require the participation of a variety of cells, cytokines, genes, and other factors, which together constitute a complex biological regulatory network. Recent studies have shown that long noncoding RNAs (lncRNAs) can be involved in the regulation of several key biological pathways and cellular functions demonstrating their critical role in diabetic wound healing. LncRNAs are a major family of RNAs with limited or no protein-coding function. Numerous studies have recently reported a strong link between oxidative stress and lncRNAs. Given that both lncRNAs and oxidative stress have been identified as potential drivers of diabetic wound healing, their link in diabetic wound healing can be inferred. However, the specific mechanism of oxidative stress related to lncRNAs in diabetic wound healing is still unclear, and elucidating the functions of lncRNAs in these processes remains a major challenge. This article reviews the mechanisms of lncRNAs related to oxidative stress in several stages of diabetic wound healing and discusses diagnostic and treatment potential of lncRNAs to treat diabetic wounds by improving oxidative stress, as well as the challenges of using lncRNAs for this purpose. It is hoped that these results will provide new targets and strategies for the diagnosis and treatment of impaired wound healing in diabetic patients.

Long noncoding RNA00324 is involved in the inflammation of rheumatoid arthritis by targeting miR-10a-5p via the NF-κB pathway

BACKGROUND

Altered expressions of genes in immune cells and synovial tissues are involved in the pathology of rheumatoid arthritis (RA). Long noncoding RNAs act as competing endogenous RNAs and can cause immune disorders. The goal of this study was to reveal the association between noncoding RNA linc00324 and RA, and a plausible action mechanism was proposed.

METHODS

RT-qPCR was used to evaluate the expression of linc00324 in peripheral blood mononuclear cells isolated from 50 RA patients and 50 healthy controls, and the correlations between linc00324 level and the clinical indicators were analyzed. Flow cytometry was used to characterize CD4+ T cells. The effects of linc00324 on cytokine production and cell proliferation of CD4+ T cells were evaluated by ELISA assay and Western blot. The interaction between linc00324 and miR-10a-5p was investigated by RNA immunoprecipitation and dual-luciferase assays.

RESULTS

The linc00324 expression was significantly enhanced in RA patients, and linc00324 expression was positively correlated with rheumatoid factor and CD4+ T cells. Overexpression of linc00324 promoted CD4+ T cells proliferation, and enhanced chemokine MIP-1α secretion and NF-κB phosphorylation level, whereas knockout of linc00324 blocked CD4+ T cell proliferation and NF-κB phosphorylation. Overexpression of miR-10a-5p led to the decrease of CD4+ T cells proliferation and NF-κB phosphorylation, and reversed the effects of linc00324 on cell proliferation and NF-κB activity.

CONCLUSION

Linc00324 was upregulated in RA and may exaggerate inflammation by targeting miR-10a-5p through NF-κB signaling pathway.

Role of ceRNA network in inflammatory cells of rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease caused by inflammatory cells. Various inflammatory cells involved in RA include fibroblast-like synoviocytes, macrophages, CD4+T-lymphocytes, B lymphocytes, osteoclasts and chondrocytes. The close interaction between various inflammatory cells leads to imbalance of immune response and disorder of the expression of mRNA in inflammatory cells. It helps to drive production of pro-inflammatory cytokines and stimulate specific antigen-specific T- and B-lymphocytes to produce autoantibodies which is an important pathogenic factor for RA. Competing endogenous RNA (ceRNA) can regulate the expression of mRNA by competitively binding to miRNA. The related ceRNA network is a new regulatory mechanism for RNA interaction. It has been found to be involved in the regulation of abnormal biological processes such as proliferation, apoptosis, invasion and release of inflammatory factors of RA inflammatory cells. Understanding the ceRNA network in 6 kinds of RA common inflammatory cells provides a new idea for further elucidating the pathogenesis of RA, and provides a theoretical basis for the discovery of new biomarkers and effective therapeutic targets.

LncRNA NNT-AS1/hsa-miR-485-5p/HSP90 axis in-silico and clinical prospect correlated-to histologic grades-based CRC stratification: A step toward ncRNA Precision

The oncogenic effects of long non-coding RNA (lncRNA) Nicotinamide Nucleotide Transhydrogenase-antisense RNA1 (NNT-AS1) role in colorectal cancer (CRC) hasn't been sufficiently inspected in relation to the Homo sapiens (hsa)-microRNA (miR)- 485-5p/ heat shock protein 90 (HSP90) axis, clinically. qRT-PCR was performed to detect lncRNA NNT-AS1 and hsa-miR-485-5p expression levels in 60 Egyptian patients' sera. HSP90 serum level was quantified using Enzyme-linked immunosorbent assay (ELISA). The relative expression level of the studied non-coding RNAs as well as the HSP90 ELISA concentration were correlated with patients clinicopathological characteristics and correlated to each other. The axis diagnostic utility in comparison with carbohydrate antigen 19-9 (CA19-9) and carcinoembryonic antigen (CEA) tumor markers (TMs) was studied by receiver operating characteristic (ROC) curve analysis. The relative lncRNA NNT-AS1 expression level fold change 56.7 (13.5-112) and HSP90 protein ELISA level 6.68 (5.14-8.77) (ng/mL) were elevated, while, for hsa-miR-485-5p 0.0474 (0.0236-0.135) expression fold change was repressed in CRC Egyptian patients' cohort sera, being compared to 28 apparently healthy control subjects. LncRNA NNT-AS1 specificity is 96.4% and a sensitivity of 91.7%, hsa-miR-485-5p showed 96.4% specificity, 90% sensitivity, and for HSP90 89.3%, 70% specificity and sensitivity, respectively. Those specificities and sensitivities were superior to the classical CRC TMs. A significant negative correlation was found between hsa-miR-485-5p with lncRNA NNT-AS1 (r = -0.933) expression fold change or with HSP90 protein blood level (r = -0.997), but, significant positive correlation was there between lncRNA NNT-AS1 and HSP90 (r = 0.927). LncRNA NNT-AS1/hsa-miR-485-5p/HSP90 axis could be a prospect for CRC development as well as diagnosis. Being correlated and related to CRC histologic grades 1-3, therefore, lncRNA NNT-AS1/hsa-miR-485-5p/HSP90 axis (not individually) expression approved clinically and in silico, could aid treatment precision.

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.

Bioinformatics analysis of ceRNA regulatory network of baicalin in alleviating pathological joint alterations in CIA rats

Rheumatoid arthritis (RA) is an autoimmune disease characterized by chronic inffammation of synovium, leading to cartilage damage, bone erosion,even joint destruction and deformity. The conventional treatment modalities in RA are associated with side effects, emphasizing the need for alternative therapeutic remedies. Baicalin possesses multiple pharmacological effects and the advantage of low toxicity. This study aimed to reveal the potential gene regulatory mechanisms underlying the alleviating effects of baicalin in joint pathological alterations in Collagen-Induced Arthritis (CIA) rat models. At 28 days after the primary immunization, 60mg/kg/d of baicalin was administered via intraperitoneal injection once daily for 40 days, and the pathological alterations of hind paw joints were examined with X-ray imaging. Subsequently, the synovial tissue of knee joints was isolated, from which total RNA was extracted, and mRNA and miRNA sequencing libraries were established. Finally, High-throughput transcriptome sequencing(RNA-seq) technology was performed, and the lncRNAs/miRNAs/mRNAs competing endogenous RNA(ceRNA) regulatory network was analyzed. The CIA model was successfully established, and baicalin treatment significantly alleviated the destruction of distal joints of CIA rat models (p < 0.01). We found that 3 potential ceRNA regulatory networks of baicalin were established, including lncRNA ENSRNOT00000076420/miR-144-3p/Fosb, lncRNA MSTRG.1448.13/miR-144-3p/Atp2b2 and lncRNA MSTRG.1448.13/miR-144-3p/Shanks. The validation results from synovial tissue of CIA rats were consistent with the RNA-Seq results. Overall, this study revealed potentially important genes and ceRNA regulatory network that mediate the alleviating effects of baicalin on joint pathological alterations in CIA rats.

Identification and preliminary validation of synovial tissue-specific genes and their-mediated biological mechanisms in rheumatoid arthritis

BACKGROUND

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease. It is well known that the formation of positive feedback between synovial hyperplasia and inflammatory infiltration is intimately associated with the occurrence and development of RA. However, the exact mechanisms still remain unknown, making the early diagnosis and therapy of RA difficult. This study was designed to identify prospective diagnostic and therapeutic biomarkers, as well as their-mediated biological mechanisms in RA.

METHODS

Three microarray datasets (GSE36700, GSE77298 and GSE153015) and two RNA-sequencing datasets (GSE89408 and GSE112656) of synovial tissues, as well as three other microarray datasets (GSE101193, GSE134087 and GSE94519) of peripheral blood were downloaded for integrated analysis. The differently expressed genes (DEGs) were identified by "limma" package of R software. Then, weight gene co-expression analysis and gene set enrichment analysis were performed to investigate synovial tissue-specific genes and their-mediated biological mechanisms in RA. The expression of candidate genes and their diagnostic value for RA were verified by quantitative real-time PCR and receiver operating characteristic (ROC) curve, respectively. Relevant biological mechanisms were explored through cell proliferation and colony formation assay. The suggestive anti-RA compounds were discovered by CMap analysis.

RESULTS

We identified a total of 266 DEGs, which were mainly enriched in cellular proliferation and migration, infection and inflammatory immune signaling pathways. Bioinformatics analysis and molecular validation revealed 5 synovial tissue-specific genes, which exhibited excellent diagnostic value for RA. The infiltration level of immune cells in RA synovial tissue was significantly higher than that in control individuals. Moreover, preliminary molecular experiments suggested that these characteristic genes may be responsible for the high proliferation potential of RA fibroblast-like synoviocytes (FLSs). Finally, 8 small molecular compounds with anti-RA potential were obtained.

CONCLUSIONS

We have proposed 5 potential diagnostic and therapeutic biomarkers (CDK1, TTK, HMMR, DLGAP5, and SKA3) in synovial tissues that may contribute to the pathogenesis of RA. These findings may shed light on the early diagnosis and therapy of RA.

Clinical implications of lncRNA LINC-PINT in cancer

Long noncoding RNAs (lncRNAs) possess the potential for therapeutic targeting to treat many disorders, including cancers. Several RNA-based therapeutics (ASOs and small interfering RNAs) have gained FDA approval over the past decade. And with their potent effects, lncRNA-based therapeutics are of emerging significance. One important lncRNA target is LINC-PINT, with its universalized functions and relationship with the famous tumor suppressor gene TP53. Establishing clinical relevance, much like p53, the tumor suppressor activity of LINC-PINT is implicated in cancer progression. Moreover, several molecular targets of LINC-PINT are directly or indirectly used in routine clinical practice. We further associate LINC-PINT with immune responses in colon adenocarcinoma, proposing the potential utility of LINC-PINT as a novel biomarker of immune checkpoint inhibitors. Collectively, current evidence suggests LINC-PINT can be considered for use as a diagnostic/prognostic marker for cancer and several other diseases.

LncRNA TP73-AS1 enhances the malignant properties of colorectal cancer by increasing SPP-1 expression through miRNA-539-5p sponging

Colorectal cancer (CC) is one of the most aggressive cancers, with a high mortality rate worldwide. This study focuses on the mechanism of CC to explore the effective therapeutic targets. We determined that LncRNA TP73-AS1 (TP-73-AS1) expression was significantly increased in CC tissues. TP73-AS1 silencing dynamically inhibited the proliferation, migratory and invasive capacity in CC cells. Mechanistically, we found that TP73-AS1 targeted miR-539-5p and miR-539-5p silencing could promote the migratory and invasive capacity in CC cells. Further study also confirmed that SPP-1 expression significantly increased after co-transfection of miR-539-5p inhibitors. Knockdown the SPP-1 can reverse malignant properties of CC cells. Si-TP73-AS1 suppressed the tumor growth of CC cells in vivo. In a word, we found that TP73-AS1 enhances the malignant properties of colorectal cancer by increasing SPP-1 expression through miRNA-539-5p sponging. And our study provides a potential therapeutic target of CC.

LncRNA XIST promotes adjuvant-induced arthritis by increasing the expression of YY1 via miR-34a-5p

Objectives: This study aims to explore the mechanism by which long non-coding ribonucleic acids (lncRNA) X-inactive specific transcript (XIST) affects the progression of adjuvant-induced arthritis (AIA).

Materials and methods: Freund's complete adjuvant was used to induce arthritis in rats. The polyarthritis, spleen and thymus indexes were calculated to evaluate AIA. Hematoxylin-eosin (H&E) staining was used to reveal the pathological changes in the synovium of AIA rats. Enzyme-linked immunosorbent assay (ELISA) was performed to detect the expression of tumor necrosis factor-alpha (TNF-α), interleukin (IL)-6 and IL-8 in the synovial fluid of AIA rats. The cell continuing kit (CCK)-8, flow cytometry, and Transwell assays were used to assess the proliferation, apoptosis, migration and invasion of transfected fibroblast-like synoviocytes (FLS) isolated from AIA rats (AIA-FLS). Dual-luciferase reporter assay was performed to verify the binding sites between XIST and miR-34b-5p or between YY1 mRNA and miR-34b-5p.

Results: The XIST and YY1 were highly expressed, and miR-34a-5p was lowly expressed in the synovium of AIA rats and in AIA-FLS. Silencing of XIST impaired the function of AIA-FLS in vitro and inhibited the progression of AIA in vivo. The XIST promoted the expression of YY1 by competitively binding to miR-34a-5p. Inhibition of miR-34a-5p strengthened the function of AIA-FLS by upregulating XIST and YY1.

Conclusion: The XIST controls the function of AIA-FLS and may promote the progression of rheumatoid arthritis via the miR-34a-5p/YY1 axis.

The novel delivery-exosome application for diagnosis and treatment of rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic degenerative disease characterized by persistent systemic synovitis, with a high risk of stiffness, pain, and swelling. It may affect the other extra-articular tissues. There is no ideal treatment for this disease at present, and it can only be controlled by medication to alleviate the prognosis. Exosomes are small vesicles secreted by various cells in the organism under normal or pathological conditions, and play a role in immune response, antigen presentation, cell migration, cell differentiation, tumor invasion and so on. Due to the adverse effects of conventional drugs and treatments in the treatment of RA, exosomes, as a nanocarrier with many advantages, can have a great impact on the loading of drugs for the treatment of RA. This article reviews the role of exosomes in the pathogenesis of RA and the progress of exosome-based therapy for RA.

Long Noncoding RNA HAFML Promotes Migration and Invasion of Rheumatoid Fibroblast-like Synoviocytes

The aggressive phenotype exhibited by fibroblast-like synoviocytes (FLSs) is critical for the progression of joint destruction in rheumatoid arthritis (RA). Long noncoding RNAs (lncRNAs) have crucial roles in the pathogenesis of diverse disorders; however, few have been identified that might be able to control the joint damage in RA. In this study, we identified an lncRNA, ENST00000509194, which was expressed at abnormally high levels in FLSs and synovial tissues from patients with RA. ENST00000509194 positively modulates the migration and invasion of FLSs by interacting with human Ag R (HuR, also called ELAVL1), an RNA-binding protein that mainly stabilizes mRNAs. ENST00000509194 binds directly to HuR in the cytoplasm to form a complex that promotes the expression of the endocytic adaptor protein APPL2 by stabilizing APPL2 mRNA. Knockdown of HuR or APPL2 impaired the migration and invasion of RA FLSs. Given its close association with HuR and FLS migration, we named ENST00000509194 as HAFML (HuR-associated fibroblast migratory lncRNA). Our findings suggest that an increase in synovial HAFML might contribute to FLS-mediated rheumatoid synovial aggression and joint destruction, and that the lncRNA HAFML might be a potential therapeutic target for dysregulated fibroblasts in a wide range of diseases.

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.

Construction and function analysis of the LncRNA-miRNA-mRNA competing endogenous RNA network in autoimmune hepatitis

AIMS

To construct the lncRNA-miRNA-mRNA competing endogenous RNA (ceRNA) network based on our microarray chip data for providing new insights into the pathogenesis of autoimmune hepatitis.

METHODS

The ceRNA pairs were obtained by calculating the co-expression relationships among the differentially expressed lncRNAs (DELs), differentially expressed microRNAs (DEMis), and differentially expressed mRNAs (DEMs) with Pearson correlation analysis and hypergeometric distribution. The data of the differentially expressed genes were obtained from our previous studies in the concanavalin A-induced AIH mouse model. The biological functions of the ceRNA network were revealed by carrying out the GO and KEGG enrichment analysis. The expression of some differentially expressed genes constructed in the ceRNA pair was validated, and the correlation to liver injury was analyzed.

RESULTS

The mRNAs constructed in the ceRNA network were most significantly annotated in the GO terms of "inflammatory response" and enriched in "Cytokine-cytokine receptor interaction" and "MAPK signaling pathway". The differences in the expression of Gm38975, mmu-miR-125a-3p, and Map3k13 between the model group and control group were significant, and the expression of these genes at a transcriptional level was positively or negatively correlated to the activity of ALT and AST as well as the amount of MDA and NO.

CONCLUSION

Our work is the first in its kind to predict and illustrate the comprehensive lncRNA-miRNA-mRNA ceRNA network associated with the etiopathogenesis of AIH. This study indicates to lay the foundation for revealing the potential roles of ceRNAs in the occurrence of AIH and provide novel treatment targets for this disease.

Artemisitene suppresses rheumatoid arthritis progression via modulating METTL3-mediated N6-methyladenosine modification of ICAM2 mRNA in fibroblast-like synoviocytes

BACKGROUND

Rheumatoid arthritis (RA) is a chronic autoimmune disease. We previously revealed that the natural compound artemisitene (ATT) exhibits excellent broad anticancer activities without toxicity on normal tissues. Nevertheless, the effect of ATT on RA is undiscovered. Herein, we aim to study the effect and potential mechanism of ATT on RA management.

METHODS

A collagen-induced arthritis (CIA) mouse model was employed to confirm the anti-RA potential of ATT. Cell Counting Kit-8 (CCK-8) and 5-ethynyl-2'-deoxyuridine (EdU) assays, cell cycle and apoptosis analysis, immunofluorescence, migration and invasion assays, quantitative real-time PCR (RT-qPCR), Western blot, RNA-sequencing (RNA-seq) analysis, plasmid construction and lentivirus infection, and methylated RNA immunoprecipitation and chromatin immunoprecipitation assays, were carried out to confirm the effect and potential mechanism of ATT on RA management.

RESULTS

ATT relieved CIA in mice. ATT inhibited proliferation and induced apoptosis of RA-fibroblast-like synoviocytes (FLSs). ATT restrained RA-FLSs migration and invasion via suppressing epithelial-mesenchymal transition. RNA-sequencing analysis and bioinformatics analysis identified intercellular adhesion molecule 2 (ICAM2) as a promoter of RA progression in RA-FLSs. ATT inhibits RA progression by suppressing ICAM2/phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/p300 pathway in RA-FLSs. Moreover, ATT inhibited methyltransferase-like 3 (METTL3)-mediated N6-methyladenosine methylation of ICAM2 mRNA in RA-FLSs. Interestingly, p300 directly facilitated METTL3 transcription, which could be restrained by ATT in RA-FLSs. Importantly, METTL3, ICAM2 and p300 expressions in synovium tissues of RA patients were related to clinical characteristics and therapy response.

CONCLUSIONS

We provided strong evidence that ATT has therapeutic potential for RA management by suppressing proliferation, migration and invasion, in addition to inducing apoptosis of RA-FLSs through modulating METTL3/ICAM2/PI3K/AKT/p300 feedback loop, supplying the fundamental basis for the clinical application of ATT in RA therapy. Moreover, METTL3, ICAM2 and p300 might serve as biomarkers for the therapy response of RA patients.

Engineered Platelet Microparticle-Membrane Camouflaged Nanoparticles for Targeting the Golgi Apparatus of Synovial Fibroblasts to Attenuate Rheumatoid Arthritis

Synovial fibroblasts in rheumatoid arthritis (RA) joints mediate synovial hyperplasia, progressive joint destruction, and the potential spread of disease between joints by producing multiple pathogenic proteins. Here, we deliver all-trans retinoic acid (ATRA) to selectively down-regulate these pathogenic factors, with a Golgi-targeting platelet microparticle-mimetic nanoplatform (termed Gol-PMMNP) which comprises a nanoparticle core and a platelet microparticle membrane coating labeled with a Golgi apparatus-targeting peptide. Gol-PMMNPs are shown to target synovial fibroblasts derived from RA patients via integrin α2β1-mediated endocytosis and accumulate in the Golgi apparatus by retrograde transport. ATRA-loaded Gol-PMMNPs (ATRA-Gol-PMMNPs) cause structural disruption of the Golgi apparatus, leading to an efficient reduction of pathogenic protein secretion in RA synovial fibroblasts. In rats with collagen-induced arthritis, Gol-PMMNPs display an arthritic joint-specific distribution, and ATRA-Gol-PMMNPs effectively reduce concentrations of pathogenic factors therein, including inflammatory cytokines, chemokines, and matrix-degrading enzymes within these joints. Additionally, ATRA-Gol-PMMNP treatment results in inflammatory remission and decreased bone erosion in both arthritic and proximal joints. Furthermore, ATRA-Gol-PMMNPs induce negligible toxicity to major organs. Taken together, ATRA-Gol-PMMNPs inhibit the progression of RA through reducing the production of multiple pathogenic mediators by synovial fibroblasts.

ST3GAL3 Promotes the Inflammatory Response of Fibroblast-Like Synoviocytes in Rheumatoid Arthritis by Activating the TLR9/MyD88 Pathway

This study is aimed at investigating the role of β-galactoside-α2,3-sialyltransferase III (ST3GAL3) in fibroblast-like synoviocytes (FLS) in rheumatoid arthritis (RA), as well as its potential mechanism of action. The Gene Expression Omnibus (GEO) database and gene set enrichment analysis (GSEA) were used to analyse the expression of ST3GAL3 and the enrichment signalling pathways associated with ST3GAL3 in RA. The effects of ST3GAL3 on tumour necrosis factor- (TNF-) α and interleukin- (IL-) 1β-treated MH7A cells were determined using methyl thiazolyl tetrazolium (MTT), transwell, and enzyme-linked immunosorbent assays (ELISA). The expression of proliferation-associated proteins and Toll-like receptor (TLR) pathway-enriched proteins was analysed using western blotting. As a main result, ST3GAL3 was screened as an overlapping upregulated gene from GSE101193 and GSE94519 datasets. ST3GAL3 expression in MH7A cells significantly increased with increasing treatment time with TNF-α or IL-1β. TLR9/myeloid differentiation primary response protein 88 (MyD88) is a downstream activation pathway of ST3GAL3. ST3GAL3 overexpression promoted MH7A cell proliferation and migration. Additionally, ST3GAL3 overexpression upregulated the expression of proliferation-associated proteins (cyclinD, cyclinE, and proliferating cell nuclear antigen) and TLR pathway enrichment factors (TLR9 and MyD88) and increased the production of matrix metallopeptidase (MMP) 1, MMP3, interleukin- (IL-) 6, and IL-8, whereas si-ST3GAL3 had the opposite effect. The addition of TLR9 agonists (CpG 2216 and CpG 2006) reversed the effects of si-ST3GAL3 on MH7A cell proliferation, migration, and inflammation. TLR9-specific siRNA reversed the effects of ST3GAL3 overexpression on MH7A cell proliferation, migration, and inflammation. In conclusion, ST3GAL3 is likely involved in RA pathogenesis by activating the TLR9/MyD88 pathway.

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.

ATF6α contributes to rheumatoid arthritis by inducing inflammatory cytokine production and apoptosis resistance

Objective

The contribution of activating transcription factor 6α (ATF6α) in rheumatoid arthritis (RA) pathogenesis, especially on fibroblast-like synoviocytes (FLSs), has been suggested by its sensitivity to inflammatory stimulus. However, the exact role and therapeutic potential of ATF6α in RA remains to be fully elucidated.

Methods

ATF6α expression was determined in joint tissues and FLS, and gain-of-function and loss-of-function analyses were applied to evaluate the biological roles of ATF6α in RA FLSs. A murine collagen-induced arthritis (CIA) model, combining both gene deletion of ATF6α and treatment with the ATF6α inhibitor Ceapin-A7, was employed. Joint inflammation, tissue destruction, circulating levels of inflammatory cytokines were assessed in CIA mice. Transcriptome sequencing analysis (RNASeq), molecular biology, and biochemical approaches were performed to identify target genes of ATF6α.

Results

ATF6α expression was significantly increased in synovium of RA patients and in synovium of mice subjected to CIA. ATF6α silencing or inhibition repressed RA FLSs viability and cytokine production but induced the apoptosis. CIA-model mice with ATF6α deficiency displayed decreased arthritic progression, leading to profound reductions in clinical and proinflammatory markers in the joints. Pharmacological treatment of mice with Ceapin-A7 reduced arthritis severity in CIA models. RNA-sequencing of wild-type and knockdown of ATF6α in RA FLSs revealed a transcriptional program that promotes inflammation and suppresses apoptosis, and subsequent experiments identified Baculoviral IAP Repeat Containing 3 (BIRC3) as the direct target for ATF6α.

Conclusion

This study highlights the pathogenic role of ATF6α-BIRC3 axis in RA and identifies a novel pathway for new therapies against RA.

The effect of long non-coding RNAs in joint destruction of rheumatoid arthritis

Rheumatoid arthritis (RA) is a systemic autoimmune disease accompanied with joint destruction. Serious joint destruction will eventually lead to disability and the decline of life quality in RA patients. At present, the therapeutic effect of drugs to alleviate joint destruction in RA is limited. Recently, accumulating evidences have shown that long non-coding RNAs (lncRNAs) play an important role in the pathogenesis of joint diseases. Therefore, this paper reviews the expression change and the action mechanism of lncRNAs in joint destruction of RA in recent years. A more comprehensive understanding of the role of lncRNAs in joint destruction will help the treatment of RA.

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.

Long Intergenic Noncoding RNAs Affect Biological Pathways Underlying Autoimmune and Neurodegenerative Disorders

Long intergenic noncoding RNAs (lincRNAs) are a class of independently transcribed molecules longer than 200 nucleotides that do not overlap known protein-coding genes. LincRNAs have diverse roles in gene expression and participate in a spectrum of biological processes. Dysregulation of lincRNA expression can abrogate cellular homeostasis, cell differentiation, and development and can also deregulate the immune and nervous systems. A growing body of literature indicates their important and multifaceted roles in the pathogenesis of several different diseases. Furthermore, certain lincRNAs can be considered potential therapeutic targets and valuable diagnostic or prognostic biomarkers capable of predicting the onset of a disease, its degree of activity, or the progression phase. In this review, we discuss possible mechanisms and molecular functions of lincRNAs in the pathogenesis of selected autoimmune and neurodegenerative disorders: multiple sclerosis, rheumatoid arthritis, systemic lupus erythematosus, Sjögren's syndrome, Huntington's disease, Parkinson's disease, Alzheimer's disease, and amyotrophic lateral sclerosis. This summary can provide new ideas for future research, diagnosis, and treatment of these highly prevalent and devastating diseases.

Long Non-Coding RNA HOTTIP is Elevated in Patients with Sepsis and Promotes Cardiac Dysfunction

BACKGROUND

Cardiac dysfunction is the most common clinical complication of sepsis. Herein, the study explored the clinical importance of long non-coding RNA (lncRNA) HOXA terminal transcript antisense RNA (HOTTIP) in the onset of sepsis and the development of cardiac dysfunction.

METHODS

120 patients with sepsis were recruited and divided into cardiac dysfunction group and non-cardiac dysfunction group. Serum HOTTIP levels were measured via RT-qPCR. AC16 cells were treated with lipopolysaccharide (LPS) for cell experiments and detected for cell viability and apoptosis.

RESULTS

High serum HOTTIP levels were tested in sepsis patients, which was associated with procalcitonin (PCT) level. Serum HOTTIP can identify sepsis cases from healthy people with the AUC of 0.927. 72 cases developed into cardiac dysfunction, accompanied by elevated levels of HOTTIP. ROC curve displayed the predictive ability of serum HOTTIP in the development of cardiac dysfunction in patients with sepsis. After adjusting for other clinical parameters, HOTTIP can independently affect the development of cardiac dysfunction. In vitro, HOTTIP knockdown promoted the recovery of cell viability and reversed LPS-induced cell apoptosis and excessive interleukin-6 (IL-6) release.

CONCLUSION

LncRNA HOTTIP is closely related to the condition of patients with sepsis and the development of cardiac dysfunction, possibly owing to its function in LPS-induced myocardial apoptosis and inflammation.

Knockdown of circ_0025908 inhibits proliferation, migration, invasion, and inflammation while stimulates apoptosis in fibroblast-like synoviocytes by regulating miR-650-dependent SCUBE2

BACKGROUND

Circular RNAs (circRNAs) are demonstrated to play vital roles in human diseases, including rheumatoid arthritis (RA). Therefore, this research aimed to explore the effects of hsa_circRNA_0025908 (circ_0025908) on RA.

METHODS

RNA expression of circ_0025908, microRNA-650 (miR-650), and Signal peptide-CUBepidermal growth factor-like containing protein 2 (SCUBE2) were assessed by real-time quantitative polymerase chain reaction; protein expression of SCUBE2, apoptosis- and invasion-related proteins was evaluated by western blot assay. Functional assays were performed using 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl-2H-tetrazol-3-ium bromide, 5-ethynyl-2'-deoxyuridine, transwell, flow cytometry, and enzyme linked immunosorbent assay assays. Dual-luciferase reporter, RNA immunoprecipitation, and RNA pull-down assays confirmed the interaction relationship among circ_0025908, miR-650, and SCUBE2.

RESULTS

Circ_0025908 was overexpressed in synovial tissues and fibroblast-like synoviocytes (FLS) from RA patients. Inhibition of circ_0025908 repressed proliferation, migration, invasion, inflammation, and cell cycle progression, while induced apoptosis in the FLS isolated from RA patients (FLS-RA), accompanied with increased Bax, cleaved caspase-3 and E-cadherin, but declined Bcl-2, N-cadherin and Vimentin. MiR-650 was a target of circ_0025908, and SCUBE2 was a target for miR-650. Silencing of miR-650 could overturned above effects of circ_0025908 knockdown in FLS-RA, whereas its overexpression could mimic those effects by downregulating SCUBE2. Additionally, SCUBE2 expression could be positively regulated by circ_0025908 and inversely regulated by miR-650. Notably, Pearson's correlation analysis confirmed the linear correlation among circ_0025908, miR-650 and SCUBE2 in these RA tissues.

CONCLUSION

Circ_0025908 inhibition can suppress FLS-RA dysfunctions through targeting miR-650/SCUBE2 axis, suggesting a new potential therapeutic clue for RA patients.