Expression of miR-146a, miR-155, and miR-223 in formalin-fixed paraffin-embedded synovial tissues of patients with rheumatoid arthritis and osteoarthritis

IDN5706 Inhibits Synovial Inflammation via Inducing M2 Polarization of Synovial Macrophages in Osteoarthritis Rats

INTRODUCTION

IDN5706 is a tetrahydro derivative of hyperforin. In this study, we aimed to explore the effect of IDN5706 on synovial macrophages in osteoarthritis (OA) rats and the underlying mechanisms.

METHODS

OA rats were employed for the in vivo experiments, and RAW264.7 cells were employed for the in vitro experiments. Histopathological changes in synovium were examined using hematoxylin-eosin staining. Cell apoptosis in synovium was assessed by TUNEL staining. Macrophage polarization was determined by immunohistochemical analysis and flow cytometry. The mRNA expression and protein level of genes were detected by qRT-PCR and Western blot. The efferocytosis of macrophages was assessed by flow cytometry.

RESULTS

IDN5706 reversed the increased CD86-positive cells (M1 macrophages) and decreased CD206-positive cells (M2 macrophages), both in synovium and synovial fluid of OA rats. The in vitro experiments further confirmed the promotion effect of IDN5706 on M2 macrophages, accompanied by the elevated Arg-1 and reduced iNOS. Also, the upregulated p-mTOR in synovium and synovial fluid of OA rats were reversed by IDN5706, and the decreased M1 macrophages and increased M2 macrophages induced by IDN5706 were reversed by the mTOR activator. IDN5706 enhanced the efferocytosis of IL-4-treated RAW264.7 cells, and the animal experiments further revealed the involvement of efferocytosis in the improvement of OA by IDN5706.

CONCLUSIONS

IDN5706 enhanced the efferocytosis of synovial macrophages by inducing M2 polarization via inhibiting p-mTOR, thus suppressing synovial inflammation and OA development, providing a theoretical basis for IDN5706 as a clinical drug for inflammatory diseases.

Potential involvement of circulating exosomal miRNA-146a in disease activity and TRAF6 gene expression in juvenile proliferative lupus nephritis

BACKGROUND

Juvenile SLE (JSLE) is a complex autoimmune disorder that predominantly affects children and adolescents with several unique challenges, and microRNA-146a (miRNA-146a) might be an interesting anti-inflammatory molecule. Because exosomes in the blood might protect miRNAs, the association between circulating exosomal miRNA-146a and lupus proinflammatory genes, such as IRAK1 and TRAF6, was studied in peripheral blood mononuclear cells from people with JSLE.

METHODS

Blood samples from 12 patients were collected every 3 months until 1 year with the recorded disease activity, and quantitative real-time PCR was used to determine the circulating exosomal miRNA-146a and the gene expression (IRAK1 and TRAF6).

RESULTS

The mean age was 12.60±0.43 years at diagnosis and all patients had a complete response at 12 months. According to the nanoparticle tracking analysis, the abundance of exosomes was significantly lower at 3, 6 and 12 months compared with 0 months, while the level of circulating exosomal miRNA-146a was significantly higher at 12 months than at diagnosis (p<0.001). There was a negative correlation between the level of circulating exosomal miRNA-146a expression and the level of TRAF6 mRNA (r=-0.30, p=0.049). Moreover, there were correlations between circulating exosomal miRNA-146a and disease severity such as SLE Disease Activity Index 2000 score, anti-double-stranded DNA antibody and proteinuria (urine protein-creatinine ratio), respectively. Therefore, increasing the level of circulating exosomal miRNA-146a, which might control TRAF6 mRNA expression, could have an effect on the production of inflammatory cytokines.

CONCLUSION

This suggests that miRNA-146a might serve as a non-invasive biomarker to evaluate the response to treatment in patients with juvenile lupus nephritis.

Cellular senescence with SASP in periodontal ligament cells triggers inflammation in aging periodontal tissue

The direct cause of periodontitis is periodontopathic bacteria, while various environmental factors affect the severity of periodontitis. Previous epidemiological studies have shown positive correlations between aging and periodontitis. However, whether and how aging is linked to periodontal health and disease in biological processes is poorly understood. Aging induces pathological alterations in organs, which promotes systemic senescence associated with age-related disease. Recently, it has become evident that senescence at the cellular level, cellular senescence, is a cause of chronic diseases through production of various secretory factors including proinflammatory cytokines, chemokines, and matrix metalloproteinases (MMPs), which is referred to the senescence-associated secretory phenotype (SASP). In this study, we examined the pathological roles of cellular senescence in periodontitis. We found localization of senescent cells in periodontal tissue, particularly the periodontal ligament (PDL), in aged mice. Senescent human PDL (HPDL) cells showed irreversible cell cycle arrest and SASP-like phenotypes in vitro. Additionally, we observed age-dependent upregulation of microRNA (miR)-34a in HPDL cells. These results suggest that chronic periodontitis is mediated by senescent PDL cells that exacerbate inflammation and destruction of periodontal tissues through production of SASP proteins. Thus, miR-34a and senescent PDL cells might be promising therapeutic targets for periodontitis in elderly people.

Synoviale Veränderungen bei Erkrankungen des rheumatologischen Formenkreises und Differenzialdiagnosen

Die Untersuchung synovialer Veränderungen kann zur Diagnose von Gelenkerkrankungen und von systemischen Erkrankungen beitragen. Die Domäne der histopathologischen Diagnostik stellt die Abgrenzung tumoröser von entzündlichen Läsionen dar. Daneben können Kristallarthropathien und bestimmte Stoffwechselerkrankungen sicher diagnostiziert werden. Unter dem histologischen Bild einer granulomatösen Synovialitis können neben einer mykobakteriellen Infektion Sarkoidosen und Fremdkörperreaktionen sowie selten genetische Erkrankungen beobachtet werden. Amyloidosen können auch in der Tunica synovialis subtypisiert werden. Molekulare Methoden erlauben die schnelle und sichere Diagnostik septischer Arthritiden und eine Keimtypisierung. Mittels dieser Methoden können auch reaktive Arthritiden klassifiziert werden, da auch hier häufig DNA oder RNA bestimmter Keime in Gewebe oder Gelenkflüssigkeit nachgewiesen werden kann. Die Diagnose der rheumatoiden Arthritis basiert auf den American College of Rheumatology(ACR)-Kriterien. Molekulare Methoden, wie die Mikro-RNA-Technologie oder proteomische Methoden können die Diagnose unterstützen.

MiR-146a expression profiles in osteoarthritis in different tissue sources: a meta-analysis of observational studies

Background

MiR-146a has been widely studied in the pathogenesis of osteoarthritis (OA); however, the results are still controversial.

Objective

This meta-analysis analyzes the expression profile of miR-146a in various tissues of OA patients.

Methods

Public databases were searched for appropriate studies published up to September 1, 2021. A case–control study comparing the OA population and a non-OA healthy population was included.

Results

26 articles were included in analysis. The results showed that the expression level of miR-146a in peripheral blood mononuclear cells (PBMCs) was significantly higher in OA patients than in controls (SMD: 1.23; 95% CI 0.08–2.37; p = 0.035) but not in plasma (SMD: 1.09; 95% CI − 0.06, 2.24; p = 0.064). The expression level of miR-146a in cartilage was also significantly higher in OA patients than in controls (SMD: 6.39; 95% CI 0.36, 12.4; p = 0.038) but not in chondrocytes (SMD: − 0.71; 95% CI − 4.15, 2.73; p = 0.687). The miR-146a level was significantly lower in synoviocytes in the OA population than in control patients (SMD: − 0.97; 95% CI − 1.68, − 0.26; p = 0.008). In synovial tissue, synovial fluid, and regulatory T cells, there was no significant difference.

Conclusion

The expression level of miR-146a in cartilage tissue and PBMCs was significantly higher in OA patients than in non-OA healthy controls. Due to the limitations of this study, more research is needed to confirm these results in the future.

Trial registration: retrospectively registered.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-022-02989-7.

MicroRNA-106b Overexpression Suppresses Synovial Inflammation and Alleviates Synovial Damage in Patients with Rheumatoid Arthritis

OBJECTIVES

To explore the effect of miR-106b on synovial inflammation and damage in rheumatoid arthritis (RA) patients, and further to investigate its possible mechanism.

METHODS

: Quantitative real-time polymerase chain reaction (qRT-PCR), immunofluorescence, in situ hybridization and immunohistochemistry assay were separately used to verify the levels of miR-106b and cytokines in the synovial tissues of patients with RA or osteoarthritis (OA). Pearson correlation analysis was conducted to examine the bivariate relationship between miR-106b and cytokines or RANKL. Following the isolation and culture of fibroblast-like synoviocytes (FLS), the cells were transfected with lentivirus-mediated miR-106b mimic, miR-106b inhibitor, and negative control miR-106b mimic, respectively. Thereafter, cell proliferation was measured by Cell Counting Kit-8 assay, and cell invasion and migration capacity was assessed by Transwell assay. Furthermore, concentration and expression of cytokines were separately detected by Enzyme linked immunosorbent assay and Western blot.

RESULTS

Compared with osteoarthritis, validation by qRT-PCR showed that RA patients had a lower level of miR-106b and higher levels of receptor activator of nuclear factor-κ B ligand (RANKL), tumor necrosis factor-a (TNF-a) and interleukin-6 (IL-6). Additionally, the scatter plot showed that the relative transcription of miR-106b level was negatively correlated to the level of TNF-a, IL-6, and RNKAL in the synovial tissues of both RA and OA patients (All P<0.05). Furthermore, miR-106b overexpression suppressed cell proliferation, migration and invasion capacity of human RA-FLS.

CONCLUSIONS

miR-106b overexpression suppresses synovial inflammation and alleviates synovial damage, thus it may be served as a potential therapeutic target for RA patients.

Host miRNA and immune cell interactions: relevance in nano-therapeutics for human health

Around 2200 miRNA (microRNA) genes were found in the human genome. miRNAs are arranged in clusters within the genome and share the same transcriptional regulatory units. It has been revealed that approximately 50% of miRNAs elucidated in the genome are transcribed from non-protein-coding genes, and the leftover miRNAs are present in the introns of coding sequences. We are now approaching a stage in which miRNA diagnostics and therapies can be established confidently, and several commercial efforts are underway to carry these innovations from the bench to the clinic. MiRNAs control many of the significant cellular activities such as production, differentiation, growth, and metabolism. Particularly in the immune system, miRNAs have emerged as a crucial biological component during diseased state and homeostasis. miRNAs have been found to regulate inflammatory responses and autoimmune disorders. Moreover, each miRNA targets multiple genes simultaneously, making miRNAs promising tools as diagnostic biomarkers and as remedial targets. Still, one of the major obstacles in miRNA-based approaches is the achievement of specific and efficient systemic delivery of miRNAs. To overcome these challenges, nanoformulations have been synthesized to protect miRNAs from degradation and enhance cellular uptake. The current review deals with the miRNA-mediated regulation of the recruitment and activation of immune cells, especially in the tumor microenvironment, viral infection, inflammation, and autoimmunity. The nano-based miRNA delivery modes are also discussed here, especially in the context of immune modulation.

Exploring the Extracellular Vesicle MicroRNA Expression Repertoire in Patients with Rheumatoid Arthritis and Ankylosing Spondylitis Treated with TNF Inhibitors

Rheumatoid arthritis (RA) and ankylosing spondylitis (AS) belong to the most common inflammatory rheumatic diseases. MicroRNAs (miRNAs) are small 18–22 RNA molecules that function as posttranscriptional regulators. They are abundantly present within extracellular vesicles (EVs), small intercellular communication vesicles that can be found in bodily fluids and that have key functions in pathological and physiological pathways. Recently, EVs have gained much interest because of their diagnostic and therapeutic potential. Using NanoString profiling technology, the miRNA repertoire of serum EVs was determined and compared in RA and AS patients before and after anti-TNF therapy to assess its potential use as a diagnostic and prognostic biomarker. Furthermore, possible functional effects of those miRNAs that were characterized by the most significant expression changes were evaluated using in silico prediction algorithms. The analysis revealed a unique profile of differentially expressed miRNAs in RA and AS patient serum EVs. We identified 12 miRNAs whose expression profiles enabled differentiation between RA and AS patients before induction of anti-TNF treatment, as well as 4 and 14 miRNAs whose repertoires were significantly changed during the treatment in RA and AS patients, respectively. In conclusion, our findings suggest that extracellular vesicle miRNAs could be used as potential biomarkers associated with RA and AS response to biological treatment.

miR-223: An Effective Regulator of Immune Cell Differentiation and Inflammation

MicroRNAs (miRNAs) play a critical role in regulating various biological processes, such as cell differentiation and immune modulation by binding to their target genes. miR-223 is a miRNA with important functions and has been widely investigated in recent years. Under certain physiological conditions, miR-223 is regulated by different transcription factors, including sirtuin1 (Sirt1), PU.1 and Mef2c, and its biological functions are mediated through changes in its cellular or tissue expression. This review paper summarizes miR-223 biosynthesis and its regulatory role in the differentiation of granulocytes, dendritic cells (DCs) and lymphocytes, macrophage polarization, and endothelial and epithelial inflammation. In addition, it describes the molecular mechanisms of miR-223 in regulating lung inflammation, rheumatoid arthritis, enteritis, neuroinflammation and mastitis to provide insights into the existing molecular regulatory networks and therapies for inflammatory diseases in humans and animals.

Frugoside delays osteoarthritis progression via inhibiting miR-155-modulated synovial macrophage M1 polarization

OBJECTIVES

Direct inhibition of M1 polarization of synovial macrophages may be a useful therapeutic treatment for OA and OA-associated synovitis. Frugoside (FGS) is a cardiac glycoside compound isolated and extracted from Calotropis gigantea. Cardiac glycosides possess interesting anti-inflammatory potential. However, the corresponding activity of FGS has not been reported. Therefore, our aim was to find direct evidence of the effects of FGS on synovial macrophage M1 polarization and OA control.

METHODS

Collagenase was used to establish an experimental mouse OA model (CIOA) with considerable synovitis. Then, FGS was intra-articular administered. The mRNA and protein levels of iNOS were analysed by real-time PCR and Western blotting in vitro. Immunohistochemical and immunofluorescence staining were used to measure the expression of F4/80, iNOS, Col2α1 and MMP13 in vivo. The levels of pro-inflammatory cytokines in FGS-treated M1 macrophage culture supernatants were analysed by flow cytometry.

RESULTS

FGS attenuates synovial inflammation and delays the development of OA in CIOA mice. Further results demonstrate that FGS inhibits macrophage M1 polarization in vitro and in vivo, which subsequently decreases the secretion of IL-6 and TNF-α, in turn delaying cartilage and extracellular matrix (ECM) degradation and chondrocyte hypertrophy. FGS inhibits macrophage M1 polarization by partially downregulating miR-155 levels.

CONCLUSION

This study demonstrates that intra-articular injection of FGS is a potential strategy for OA prevention and treatment, even at an early stage of disease progression. This is a novel function of FGS and has promising future clinical applications.

Vaspin regulated cartilage cholesterol metabolism through miR155/LXRα and participated in the occurrence of osteoarthritis in rats

AIMS

This study intends to explore the role of Vaspin and cholesterol metabolism in the process of osteoarthritis (OA) and its mechanism in vitro and in vivo.

MAIN METHODS

In vitro, chondrocytes were treated with interleukin-1β (IL-1β, 20 ng/mL) in combination with Vaspin at different concentrations for 48 h. The expressions of Aggrecan (ACAN), Collagen 2a1 (Col2a1), A Disintegrin And Metalloproteinase with Thrombo Spondin type 1 motifs 5 (ADAMTS 5), and Matrix metalloproteinase 13 (MMP13) were detected. In vivo, the expression of liver X receptor (LXRα) and other Cholesterol efflux related genes were detected in the rat OA knee cartilage-induced by papain.

KEY FINDINGS

In vitro, in a concentration-dependent manner, Vaspin reversed the decreased expression of ACAN and Col2a1, and the increased expression of ADAMTS 5 and MMP13 caused by IL-1β. Besides, Vaspin promoted the expression of LXRα and other Cholesterol efflux related genes in a concentration-dependent manner in chondrocytes. However, miR155 mimics reversed the Vaspin-induced expression changes of cholesterol efflux pathway in chondrocytes. In vivo, the expression of LXRα and other Cholesterol efflux related genes were decreased in the rat OA knee cartilage-induced by papain. Besides, the level of Vaspin was reduced and the miroRNA155 (miR155) expression was increased in OA knee cartilage of rats.

SIGNIFICANCE

In conclusion, the decreased expression of Vaspin inhibited the expression of Cholesterol efflux pathway via miR155/LXRα. Finally, the inhibited Cholesterol efflux pathway led to the cholesterol accumulation and OA in cartilage.

MicroRNA-146a-5p enhances T helper 17 cell differentiation via decreasing a disintegrin and metalloprotease 17 level in primary sjögren's syndrome

In clinical practice, we found that microRNA (miR)-146a-5p is significantly up-regulated in peripheral blood mononuclear cells (PBMCs) of primary sjögren’s syndrome (pSS) patients. In vitro experiments confirmed that miR-146a-5p promotes T helper 17 (Th17) cell differentiation, but the specific mechanism is still unknown. To solve this problem, 20 pSS patients and 20 healthy subjects were enrolled in this study and PBMCs were isolated from their blood. The expression of the membrane IL-23 R (mIL-23 R) in PBMCs was determined. CD3⁺ T cells were also isolated and used to further analyze the relationship between the ectodomain shedding of mIL-23 R and a disintegrin and metalloprotease 17 (ADAM17). Finally, miR-146a-5p inhibitor and mimics were transfected into PBMCs to evaluate the relationship between ADAM17 and mIL-23 R, and explore the role of mIL-23 R and ADAM17 in Th17 cell differentiation. Our results revealed a significantly increased expression of miR-146a-5p in PBMCs from pSS patients and significantly increased percentage of Th17 cells compared to PBMCs from healthy controls. Under polarization culture conditions, pSS patient-derived PBMCs can more easily differentiate into Th17 cells, which was, to a great extent, attributable to the increased expression of mIL-23 R. Moreover, ADAM17, an ectodomain sheddase of mIL-23 R, was targeted and negatively regulated by miR-146a-5p, which reduced the ectodomain shedding of mIL-23 R. Overall, our results suggested that miR-146a-5p could promote Th17 cell differentiation through targeting and negatively regulating ADAM17. Thus, these results might offer a new approach in the treatment of pSS.

MicroRNA-124-3p affects myogenic differentiation of adipose-derived stem cells by targeting Caveolin-1 during pelvic floor dysfunction in Sprague Dawley rats

Background

The aim of this study was to investigate using myogenic differentiation of adipose stem cells for the treatment of female pelvic floor dysfunction (PFD) and aimed to further study the influences of microRNA-124-3p (miR-124-3p) in the process of myogenic differentiation of adipose-derived stem cells (ADSCs) through targeting Caveolin-1 (Cav1) during PFD in Sprague Dawley (SD) rats.

Methods

The ADSCs were separated from 6–8-week-old female SD rats (n=25) and were cultivated. Then, we observed the cell status and conducted fat and osteogenic experiments. We then constructed an ADSC-green fluorescent protein (GFP) stable transfer strain. Flow cytometry was used to identify the positive rates of CD44, CD90, and CD45 in ADSCs and ADSC-GFP. Real-time quantitative polymerase chain reaction (qRT-PCR) and western blotting were used to mRNA and protein expression levels. Myogenic differentiation of ADSCs was measured with immunofluorescence methods. A dual-luciferase reporter assay was executed to affirm whether Cav1 was a target of miR-124-3p.

Results

The isolated ADSCs cells were in good condition under the microscope. The results of flow cytometry showed that the positive rate of CD44 and CD90 was high, and the positive rate of CD45 was low in ADSCs and ADSC-GFP. Under normal culture conditions, ADSCs-GFP cells can be massively adipated and osteogenic. After 5-Aza induced ADSC-GFP myogenic differentiation, the level of miR-124-3p was significantly increased. We found that MiR-124-3p mimics promoted the myogenic differentiation of ADSCs. Moreover, we discovered that Cav1 was a target gene of miR-124-3p and was negatively regulated by miR-124-3p. The results of leak point pressure (LPP), hematoxylin and eosin (HE), and Masson showed that the collagen fiber content of the PFD group was lower than that of the control group; the collagen fiber content of ADSC-GFP, 5-Aza, or miR-124-3p mimics were increased after intervention. Furthermore, the outcomes qRT-PCR, western blotting, and immunofluorescence suggested that miR-124-3p facilitated the survival ADSC-GFP fat transplantation by regulating many key factors in vivo.

Conclusions

These results proofed that miR-124-3p could accelerate myogenic differentiation of ADSCs by down-regulating Cav1 to improve PFD in SD rats, which will pave the way for therapeutic delivery of miRNA targeting PFD disease.

miRNA-146a Improves Immunomodulatory Effects of MSC-derived Exosomes in Rheumatoid Arthritis

Background:

Rheumatoid arthritis (RA) is a severe inflammatory joint disorder, and several studies have taken note of the probability that microRNAs (miRNAs) play an important role in RA pathogenesis. MiR-146 and miR-155 arose as primary immune response regulators. Mesenchymal stem cells (MSCs) immunomodulatory function is primarily regulated by paracrine factors, such as exosomes. Exosomes, which serve as carriers of genetic information in cell-to-cell communication, transmit miRNAs between cells and have been studied as vehicles for the delivery of therapeutic molecules.

Aims:

The current research aimed to investigate the therapeutic effect of miR-146a/miR-155 transduced mesenchymal stem cells (MSC)-derived exosomes on the immune response.

Methods:

Here, exosomes were extracted from normal MSCs with over-expressed miR-146a/miR-155; Splenocytes were isolated from collagen-induced arthritis (CIA) and control mice. Expression levels miR-146a and miR-155 were then monitored. Flow cytometry was performed to assess the impact of the exosomes on regulatory T-cell (Treg) levels. Expression of some key autoimmune response genes and their protein products, including retinoic acid-related orphan receptor (ROR)-γt, tumor necrosis factor (TNF)-α, interleukin (IL)-17, -6, -10, and transforming growth factor (TGF)-β in the Splenocytes was determined using both quantitative real-time PCR and ELISA. The results showed that miR-146a was mainly down-regulated in CIA mice. Treatment with MSC-derived exosomes and miR-146a/miR-155-transduced MSC-derived exosomes significantly altered the CIA mice Treg cell levels compared to in control mice.

Results:

Ultimately, such modulation may promote the recovery of appropriate T-cell responses in inflammatory situations such as RA.

Conclusion:

miR-146a-transduced MSC-derived exosomes also increased forkhead box P3 (Fox- P3), TGFβ and IL-10 gene expression in the CIA mice; miR-155 further increased the gene expressions of RORγt, IL-17, and IL-6 in these mice. Based on the findings here, Exosomes appears to promote the direct intracellular transfer of miRNAs between cells and to represent a possible therapeutic strategy for RA. The manipulation of MSC-derived exosomes with anti-inflammatory miRNA may increase Treg cell populations and anti-inflammatory cytokines.

Relationship of miRNA-146a to systemic lupus erythematosus: A PRISMA-compliant meta-analysis

BACKGROUND AND OBJECTIVE

miRNA-146a is a microRNA that plays an important role in systemic lupus erythematosus (SLE). Several studies have examined the role of miRNA-146a in SLE, but have demonstrated equivocal or even contradictory conclusions. Therefore, this meta-analysis aimed to assess the role of miRNA-146a in SLE by examining data from previous studies.

METHODS

A meta-analysis of relevant papers published before August 31, 2019, in the WanFang, Chinese Biomedical Literature Database (CBM), Chinese National Knowledge Infrastructure (CNKI), PubMed, EMBASE, and Web of Science databases was performed to verify the relationship of miRNA-146a expression level to SLE. Two investigators independently extracted the data and conducted a quality assessment of the studies. All statistical analyses were performed using Stata 14.0. Trial sequence analysis (TSA) was conducted to assess the quality and strength of the studies using the TSA software.

RESULTS

Six publications, involving 151 SEL patients and 132 healthy individuals as controls were included in this meta-analysis. The results showed that the expression of miRNA-146a was associated with SLE risk [standard mean difference (SMD) = -1.21, 95% confidence interval (95% CI) (-2.18, -0.23), P = .015]. The stratified analysis revealed that the expression of miRNA-146a was highly related to higher SLE risk among Asian (SMD = -1.30, 95% CI (-2.52, -0.07), P = .038) and Caucasian (SMD = -0.72, 95% CI (-1.20, -0.24), P = .003) populations. Besides, the serum levels of miRNA146a were significantly different (SMD = -1.73, 95% CI (-3.11, -0.36), P = .014). The TSA revealed that the cumulative Z-curve crossed the typical boundary value, and reached the TSA monitoring boundary, but did not reach the required information size. This indicates that even if the cumulative sample size did not meet required information size, no more trials were needed and a reliable conclusion was reached in advance. Sensitivity analyses indicated the instability of the meta-analysis.

CONCLUSIONS

Overall, the expression of miRNA-146a is associated with SLE risk. Therefore, miRNA-146a is a promising candidate for the effective diagnosis of SLE. But, due to the limitations of this study, it is necessary to cautiously explain the results of this study.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42019151381.

MicroRNAs in Synovial Pathology Associated With Osteoarthritis

Osteoarthritis (OA) is the most common type of arthritis, a disease that affects the entire joint. The relative involvement of each tissue, and their interactions, add to the complexity of OA, hampering our understanding of the underlying molecular mechanisms, and the generation of a disease modifying therapy. The synovium is essential in maintaining joint homeostasis, and pathologies associated with the synovium contribute to joint destruction, pain and stiffness in OA. MicroRNAs (miRNAs) are post-transcriptional regulators dysregulated in OA tissues including the synovium. MiRNAs are important contributors to OA synovial changes that have the potential to improve our understanding of OA and to act as novel therapeutic targets. The purpose of this review is to summarize and integrate current published literature investigating the roles that miRNAs play in OA-related synovial pathologies including inflammation, matrix deposition and cell proliferation.

The miRNA-mRNA interactome of murine induced pluripotent stem cell-derived chondrocytes in response to inflammatory cytokines

Osteoarthritis (OA) is a degenerative joint disease, and inflammation within an arthritic joint plays a critical role in disease progression. Pro-inflammatory cytokines, specifically IL-1 and TNF-α, induce aberrant expression of catabolic and degradative enzymes and inflammatory cytokines in OA and result in a challenging environment for cartilage repair and regeneration. MicroRNAs (miRNAS) are small noncoding RNAs and are important regulatory molecules that act by binding to target messenger RNAs (mRNAs) to reduce protein synthesis and have been implicated in many diseases, including OA. The goal of this study was to understand the mechanisms of miRNA regulation of the transcriptome of tissue-engineered cartilage in response to IL-1β and TNF-α using an in vitro murine induced pluripotent stem cell (miPSC) model system. We performed miRNA and mRNA sequencing to determine the temporal and dynamic responses of genes to specific inflammatory cytokines as well as miRNAs that are differentially expressed (DE) in response to both cytokines or exclusively to IL-1β or TNF-α. Through integration of mRNA and miRNA sequencing data, we created networks of miRNA-mRNA interactions which may be controlling the response to inflammatory cytokines. Within the networks, hub miRNAs, miR-29b-3p, miR-17-5p, and miR-20a-5p, were identified. As validation of these findings, we found that delivery of miR-17-5p and miR-20a-5p mimics significantly decreased degradative enzyme activity levels while also decreasing expression of inflammation-related genes in cytokine-treated cells. This study utilized an integrative approach to determine the miRNA interactome controlling the response to inflammatory cytokines and novel mediators of inflammation-driven degradation in tissue-engineered cartilage.

Quercetin suppresses migration and invasion by targeting miR-146a/GATA6 axis in fibroblast-like synoviocytes of rheumatoid arthritis

Background: Rheumatoid arthritis (RA) is a systematic autoimmune disease which may lead to joint dysfunction and disability. Aberrant migration and invasion of fibroblast-like synoviocytes (FLSs) is one of the most predominant etiopathogenesis of RA. Quercetin is a bioflavonoid which is implicated in the development of RA, yet its role in regulating the migration and invasion of FLSs is still elusive. The aim of this study is to investigate the impact of quercetin treatment on migration and invasion of FLSs and the underlying mechanism.Methods: Capacity of migration and invasion of FLSs were assessed using transwell assay. Immunofluorescence assay was used to determine the expression of F-actin. The RNA levels of miR-146a and GATA transcription factor 6 (GATA6) were measured using quantitative real-time PCR. Western blot was used to examine the protein level of GATA6. The correlation between miR-146a and GATA6 was validated using luciferase reporter assay.Results: Transwell assay revealed that the migration and invasion of FLSs were significantly inhibited after quercetin treatment, which was also proved by decreased expression of F-actin. The RNA level of miR-146a was decreased in RA tissues and was negatively related to the expression of GATA transcription factor 6 (GATA6). Quercetin treatment elevated the RNA level of miR-146a, but suppressed the expression of GATA6 in FLSs. Further luciferase reporter assay validated that GATA6 is a downstream target of miR-146a. Besides, miR-146a inhibited the migration and invasion of FLSs, and further GATA6 over-expression abrogated the miR-146a-induced inhibition. In addition, specific anti-miR-146a inhibitor abolished quercetin-mediated suppression of migration and invasion of FLSs.Conclusion: Our study suggested that quercetin suppresses the migration and invasion of FLSs via regulating the miR-146a/GATA6 axis.

Comparison of MicroRNA Expression in Tears of Normal Subjects and Sjögren Syndrome Patients

Purpose

Deregulated expression of several microRNAs (miRNAs) in sera or salivary glands of patients with Sjögren syndrome (SS) has been reported. However, none have investigated miRNAs in samples that can represent lacrimal glands. We compared the miRNAs expression in the tears of SS patients and healthy controls. Moreover, we investigated the correlation between miRNAs expression and ocular staining score (OSS).

Methods

Individual tear samples were collected from 18 SS patients and 8 age-matched controls. Clinical ophthalmologic assessments included Schirmer I test, tear film breakup time (tBUT), and OSS. The expression of 43 different miRNAs in tears was measured using real-time polymerase chain reaction, and compared between the SS patients and controls. And we also compared between the three groups of control, primary SS, and secondary SS patients. The correlation between the miRNA expression and OSS was evaluated.

Results

The expression levels of miR-16-5p, miR-34a-5p, miR-142-3p, and miR-223-3p were significantly upregulated in patients with SS when compared with those in the control group (P < 0.05). The expression of 10 miRNAs (miR-30b-5p, miR-30c-5p, miR-30d-5p, miR-92a-3p, miR-134-5p, miR-137, miR-302d-5p, miR-365b-3p, miR-374c-5p, miR-487b-3p) was significantly downregulated in the SS patients (P < 0.05). Eight miRNAs showed statistically significant differences between the three groups of control, primary SS and secondary SS. All 14 miRNAs with significant differences in SS patients and control group were not significantly correlated with OSSs.

Conclusions

The 14 differentially expressed miRNAs may be involved in the pathogenesis of SS, in particular, related to autoimmunity and neuropathy.

Inhibition of miR‑155‑5p attenuates the valvular damage induced by rheumatic heart disease

Autoimmunity is involved in the valvular damage caused by rheumatic heart disease (RHD). Increased evidence has linked microRNAs (miRNAs/miRs) to autoimmune disease. Signal transducer and activator of transcription 3 (STAT3) and sphingosine-1-phosphate receptor 1 (S1PR1) and suppressor of cytokine signaling 1 (SOCS1) have been widely studied for their roles in autoimmunity and inflammation. Thus, the current study aims to investigate the role played by miR-155-5p in RHD-induced valvular damage via the S1PR1, SOCS1/STAT3 and interleukin (IL)-6/STAT3 signaling pathways. An RHD rat model was induced by inactivated Group A streptococci and complete Freund's adjuvant. A recombinant adeno-associated virus (AAV-miR155-inhibitor) was used to inhibit the expression of miR-155-5p in the heart. Inflammation and fibrosis were assessed by hematoxylin and eosin staining and Sirius red staining. The expression of miR-155-5p in valvular tissues and serum exosomes was detected by reverse transcription-quantitative PCR. S1PR1, SOCS1, STAT3, phosphorylated STAT3, IL-6 and IL-17 protein expression was detected by western blotting and immunohistochemistry. The relationships between miR-155-5p and S1PR1 and SOCS1 were detected by dual luciferase assays. Cytokine concentrations were measured by ELISA. The expression of miR-155-5p in valve tissues and serum exosomes was increased along with decreased S1PR1 and activated SOCS1/STAT3 signaling in the RHD model. The expression of IL-6 and IL-17 was increased in the valves and the serum. Dual luciferase assays showed that miR-155-5p directly targeted S1PR1 and SOCS1. Inhibition of valvular miR-155-5p through AAV pretreatment increased S1PR1 expression and inhibited activation of the SOCS1/STAT3 signal pathway as a result of attenuated valvular inflammation and fibrosis as well as a decrease in IL-6 and IL-17 in the valves and serum. These results suggest that inhibition of miR-155-5p can reduce RHD-induced valvular damage via the S1PR1, SOCS1/STAT3 and IL-6/STAT3 signaling pathways.

BMP9 inhibits the proliferation and migration of fibroblast-like synoviocytes in rheumatoid arthritis via the PI3K/AKT signaling pathway

Rheumatoid arthritis (RA) is a chronic autoimmune inflammatory disease; its pathogenesis remains unclear. Fibroblast-like synoviocytes (FLSs) play a vital role in the pathogenesis of RA. BMP9, a member of the bone morphogenetic protein (BMP) family, has been reported to play a critical role in both normal physiological processes and the pathology of various diseases. In this study, we explored the function and underlying mechanisms of BMP9 in the proliferation and migration of RA FLSs. We found that BMP9 expression was significantly downregulated in the synovial tissues of RA patients, compared with those of OA patients; BMP9 expression was also low in adjuvant-induced arthritis (AA) samples. Additionally, inhibition of BMP9 expression by BMP9 siRNA increased the proliferation of AA FLSs, and the expression of c-Myc, Cyclin D1, MMP-2, and MMP-9, but not TIMP-1, in AA FLSs. However, AA FLSs transfected with the overexpression vector PEX-3-BMP9 showed reduced proliferation and expression of c-Myc, Cyclin D1, MMP-2, and MMP-9, but not TIMP-1. Further studies indicate that BMP9 may induce the activation of the PI3K/AKT signaling pathway. Thus, these data indicate that BMP9 may play a critical role in the proliferation and migration of FLSs through the activation of the AKT signaling pathway.

PSTPIP2 Inhibits the Inflammatory Response and Proliferation of Fibroblast-Like Synoviocytes in vitro

Rheumatoid arthritis (RA) is a chronic autoimmune inflammatory disease and its pathogenesis remains unclear. Fibroblast-like synoviocytes (FLSs) play an important role in the pathogenesis of RA. Proline-serine-threonine phosphatase interacting protein 2 (PSTPIP2) is an adaptor protein, which is associated with auto-inflammatory disease. In this study, we selected adjuvant-induced arthritis (AIA) as animal model to study the role of PSTPIP2 in FLSs. We found that the expression of PSTPIP2 was significantly down-regulated in synovial tissues and FLSs of AIA rat compared with normal group. And overexpression of PSTPIP2 could inhibit the proliferation and inflammatory response of FLSs. Moreover, the proliferation and inflammatory response of FLSs were promoted with PSTPIP2 silencing treatment. In terms of mechanism, we found that the expression of PSTPIP2 was closely related to NF-κB signaling pathway. Overall, our results suggested that PSTPIP2 inhibits the proliferation and inflammatory response of FLSs, which might be closely related to NF-κB signaling pathway.

MiR-146a levels in rheumatoid arthritis and their correlation with disease activity: a meta-analysis

OBJECTIVE

To evaluate the relationship between miR-146a levels and rheumatoid arthritis (RA), and the correlation with RA activity.

METHODS

For the meta-analysis, we searched the PubMed, MEDLINE, EMBASE and Cochrane databases, comparing miR-146a levels in patients with RA and controls, and correlation coefficients between miR-146a levels and Disease Activity Score for 28 joints (DAS28) and erythrocyte sedimentation rate (ESR) in patients with RA.

RESULTS

Fourteen studies, totaling 683 patients with RA and 477 controls, were available. miR-146a levels were significantly higher in the RA group than in the control group (standardized mean difference [SMD] = 0.546, 95% CI = 0.033-1.059, P = 0.037). Stratification by adjustment for age and/or sex revealed significantly higher miR-146a levels in the adjusted, but not in the non-adjusted group (SMD = 0.747, 95% CI = 0.094-1.400, P = 0.025; SMD = 0.431, 95% CI = -0.430-1.291, P = 0.326, respectively). Stratification by sample size showed significantly higher miR-146a levels in RA groups of large sample sizes (N ≥ 50), but not in those of small size. miR-146a levels in synovial tissue/fluid were significantly higher in the RA group than in the OA group (SMD = 1.305, 95% CI = 1010-1.639, P < 0.001). A significant positive correlation was found between miR-146a levels and ESR (correlation coefficient = 0.534, 95% CI = 0.029-0.822, P = 0.039).

CONCLUSIONS

Circulating and synovial tissue/fluid miR-146a levels are high in patients with RA, and circulating miR-146a levels positively correlate with ESR.

Differential miRNAomics of the synovial membrane in knee osteoarthritis induced by bilateral anterior cruciate ligament transection in rats

The differential microRNA (miRNA) omics of the synovial membrane were investigated using a rat model of knee osteoarthritis (KOA) induced by bilateral anterior cruciate ligament transection, which produced pathological biomarkers in KOA. Sprague‑Dawley rats were randomly divided into two groups; Sham‑operated and KOA‑operated group. The KOA rats were subjected to bilateral anterior cruciate ligament transection. After 6 weeks, total RNA was extracted from the knee joint synovial membrane of the rats and a microRNA (miR) microarray was performed to identify differentially expressed miRs. Subsequently, the obtained differentially expressed miRs were validated by reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR) analysis. A total of 24 miRs were identified with alterations ≥1.5‑fold in the synovial membrane in the KOA‑operated group compared with the sham‑operated group, of which 4 miRs (miR‑532‑5p, ‑200b‑5p, ‑377‑3p and ‑759‑5p) were decreased and 20 miRs (miR‑382‑3p, ‑223‑3p, ‑100‑5p, ‑30d‑5p, ‑183‑5p, ‑130, ‑92b‑3p, ‑125b‑3p, ‑151‑3p, ‑155‑3p, 27a‑3p, ‑146b‑3p, ‑885‑5p, ‑352, ‑184, ‑345‑5p, ‑30a‑5p and ‑9a‑5p) were increased. Subsequently, RT‑qPCR was used to validate the expressions of miR‑223, ‑100, ‑345, ‑130, ‑382, ‑377, ‑352, ‑200b, ‑9a and ‑183, which were upregulated by a fold change of ≥1.5 in synovial membranes of KOA rats compared with shams. Furthermore, in vitro miR‑223 mimic could suppress the luciferase activity of NACHT, LRR and PYD domains‑containing protein 3 (NLRP3) 3' untranslated region by detecting of dual luciferase reporter vector. Additionally, the expression of NLRP3, interleukin (IL)‑1β and IL‑18 significantly increased in the synovial membrane of KOA rats. A total of 24 different miRs were determined by comparing the miRNAomics in the synovial membrane of the KOA model rats. Furthermore, the miR‑233‑regulated NLRP3 inflammasome was implicated in synovial membrane injury, which may be an important mechanism of KOA pathogenesis.

The Micro-RNA Expression Profiles of Autoimmune Arthritis Reveal Novel Biomarkers of the Disease and Therapeutic Response

Rheumatoid arthritis (RA) is a chronic autoimmune disease of the joints affecting about 0.3–1% of the population in different countries. About 50–60 percent of RA patients respond to presently used drugs. Moreover, the current biomarkers for RA have inherent limitations. Consequently, there is a need for additional, new biomarkers for monitoring disease activity and responsiveness to therapy of RA patients. We examined the micro-RNA (miRNA) profile of immune (lymphoid) cells of arthritic Lewis rats and arthritic rats treated with celastrol, a natural triterpenoid. Experimental and bioinformatics analyses revealed 8 miRNAs (miR-22, miR-27a, miR-96, miR-142, miR-223, miR-296, miR-298, and miR-451) and their target genes in functional pathways important for RA pathogenesis. Interestingly, 6 of them (miR-22, miR-27a, miR-96, miR-142, miR-223, and miR-296) were further modulated by celastrol treatment. Interestingly, serum levels of miR-142, miR-155, and miR-223 were higher in arthritic versus control rats, whereas miR-212 showed increased expression in celastrol-treated rats compared with arthritic rats or control rats. This is the first study on comprehensive miRNA expression profiling in the adjuvant-induced arthritis (AA) model and it also has revealed new miRNA targets for celastrol in arthritis. We suggest that subsets of the above miRNAs may serve as novel biomarkers of disease activity and therapeutic response in arthritis.

IL-1β-induced miR-34a up-regulation inhibits Cyr61 to modulate osteoarthritis chondrocyte proliferation through ADAMTS-4

Osteoarthritis (OA) is the most prevalent degenerative joint disease with multifactorial etiology caused by risk factors. The degradation of aggrecan by upregulated ADAMTS (a disintegrin and metalloproteinase with thrombospondin motifs) is the key event in the development of OA. ADAMTS-4 contributes to aggrecan degradation in human OA. Cysteine-rich angiogenic inducer 61 (Cyr61), which is associated with diseases related to chronic inflammation, is found in articular cartilage from patients with osteoarthritis and appears to suppress ADAMTS-4 activity, possibly leading to chondrocyte cloning. Herein, we first revealed that Cyr61 and ADAMTS-4 protein levels were remarkably increased in OA cartilage tissues and OA chondrocytes, and verified Cyr61 regulation of ADAMTS-4 in normal and OA chondrocyte. Further, we revealed that Cyr61 could promote OA chondrocyte proliferation through inhibiting ADAMTS-4. Overproduction of inflammatory cytokines plays a vital role in the pathological development of OA; herein, we demonstrated that IL-1β inhibited Cyr61, while promoted ADAMTS-4 expression. By using online tools and luciferase assays, we confirmed that miR-34a, a regulatory miRNA of chondrocyte proliferation, could directly bind to the 3'-UTR of Cyr61 to inhibit its expression; further, IL-1β regulated Cyr61 and ADAMTS-4 expression through miR-34a. In OA cartilage tissues, miR-34a, and IL-1β mRNA expression was up-regulated and positively correlated; miR-34a and Cyr61 mRNA was positively correlated, further indicating that suppressing miR-34a expression might rescue IL-1β-induced Cyr61 suppression, and promote OA chondrocyte proliferation. Taken together, we provided novel experimental basis for rescuing OA chondrocyte proliferation through miR-34a/Cyr61 axis.

Altered levels of immune-regulatory microRNAs in plasma samples of patients with lupus nephritis

Introduction: Lupus nephritis (LN) is a major cause of mortality and morbidity in the patients with lupus, a chronic autoimmune disease. The role of genetic and epigenetic factors is emphasized in the pathogenesis of LN. The aim of the present study was to evaluate the levels of immune-regulatory microRNAs (e.g., miR-31, miR-125a, miR-142-3p, miR-146a, and miR-155) in plasma samples of patients with LN.

Methods: In this study, 26 patients with LN and 26 healthy individuals were included. The plasma levels of the microRNAs were evaluated by a quantitative real-time PCR. Moreover, the correlation of circulating plasma microRNAs with disease activity and pathological findings along with their ability to distinguish patients with LN were assessed.

Results: Plasma levels of miR-125a (P = 0.048), miR-146a (P = 0.005), and miR-155 (P< 0.001) were significantly higher in comparison between the cases and controls. The plasma level of miR-146a significantly correlated with the level of anti-double strand-DNA antibody and proteinuria. Moreover, there was a significant correlation between miR-142-3p levels and disease chronicity and activity index (P <0.05). The multivariate ROC curve analysis indicated the plasma circulating miR-125a, miR-142-3p, miR-146, and miR-155 together could discriminate most of the patients with LN from controls with area an under curve (AUC) of 0.89 [95% CI, 0.80-0.98, P<0.001], 88% sensitivity, and 78% specificity.

Conclusion: Based on the findings of the present study, the studied microRNAs may be involved in the pathogenesis and development of LN and have the potential to be used as diagnostic and therapeutic markers in LN.

15 years of the histopathological synovitis score, further development and review: A diagnostic score for rheumatology and orthopaedics

The histopathological synovitis score evaluates the immunological and inflammatory changes of synovitis in a graduated manner generally customary for diagnostic histopathological scores. The score results from semiquantitative evaluation of the width of the synovial surface cell layer, the cell density of the stroma and the density of the inflammatory infiltration into 4 semiquantitative levels (normal 0, mild 1, moderate 2, severe 3). The addition of these values results in a final score of 0-9 out of 9. On the basis of this summation the condition is divided into low-grade synovitis and high-grade synovitis: A synovitis score of 1 to≤4 is called low-grade synovitis (arthrosis-associated/OA synovitis, posttraumatic synovitis, meniscopathy-associated synovitis and synovitis with haemochromatosis). A synovitis score of≥5 to 9 is called high-grade synovitis (rheumatoid arthritis, psoriatic arthritis, Lyme arthritis, postinfection/reactive arthritis and peripheral arthritis with Bechterew's disease). By means of the synovitis score it is therefore possible to distinguish between degenerative/posttraumatic diseases (low-grade synovitis) and inflammatory rheumatic diseases (high-grade synovitis) with a sensitivity of 61.7% and a specificity of 96.1%. The diagnostic accuracy according to ROC analysis (AUC: 0.8-0.9) is good. Since the first publication (2002) and an associated subsequent publication (2006), the synovitis score has nationally and internationally been accepted for histopathological assessment of the synovitis. In a PubMed data analysis (status: 14.02.2017), the following citation rates according to Cited by PubMed Central articles resulted for the two synovitis score publications: For DOI: 10.1078/0344-0338-5710261 there were 29 Cited by PubMed Central articles and for the second extended publication DOI:10.1111/j.1365-2559.2006.02508 there were 44 Cited by PubMed Central articles. Therefore a total of 73 PubMed citations are observed over a period of 15 years, which demonstrates an international acceptance of the score. This synovitis score provides for the first time a diagnostic, standardised and reproducible histopathological evaluation method enabling a contribution to the differential diagnosis of chronic inflammatory general joint diseases. This is particularly the case by incorporation into the joint pathology algorithm. To specify the synovitis score an immunohistochemical determination of various inflammation-relevant CD antigens is proposed to enable a risk stratification of high-grade synovitis (e.g.: progression risk and sensitivity for biologicals).

The role of microRNAs in the pathogenesis of autoimmune diseases

MicroRNAs (miRNAs) are single-stranded, endogenous non-coding small RNAs, ranging from 18 to 25 nucleotides in length. Growing evidence suggests that miRNAs are essential in regulating gene expression, cell development, differentiation and function. Autoimmune diseases are a family of chronic systemic inflammatory diseases. Recent findings on miRNA expression profiles have been suggesting their role as biomarkers in autoimmune diseases such as systemic lupus erythematosus, rheumatoid arthritis and Sjögren's syndrome. In this review, we summarize the characteristics of miRNAs and their functional role in the immune system and autoimmune diseases including systemic lupus erythematosus, primary Sjögren's syndrome, rheumatoid arthritis, systemic sclerosis, multiple sclerosis and psoriasis; moreover, we depict the advantages of miRNAs in modern diagnostics.