Circulating plasma microRNA profiling in patients with polymyositis/dermatomyositis before and after treatment: miRNA may be associated with polymyositis/dermatomyositis

miR-6516-3p-mediated downregulation of the endogenous MMP-9 inhibitor RECK in mesangial cells might exacerbate lupus nephritis

BACKGROUND

MicroRNAs (miRNAs) regulate biological processes by inhibiting translation and causing mRNA degradation. In this study, we identified the miRNAs involved in the development and progression of lupus nephritis (LNs) and verified their roles.

METHODS

Total RNA, extracted from PBMCs collected from patients with LNs before and after treatment, was used for miRNA array analysis to identify miRNAs whose expression was significantly altered. The results of this analysis were confirmed using qRT-PCR. The identified miRNAs were transfected into normal human mesangial cells (NHMCs), human renal proximal tubule epithelial cells (RPTECs), human umbilical vein endothelial cells (HUVECs), and THP-1-derived macrophages (THP1-Mφ) to investigate their biological functions.

RESULTS

Three miRNAs were altered in PBMCs before and after treatment of LNs. Among these miRNAs, hsa-miR-6516-3p promoted TNF-α-induced expression of MMP-9 in NHMCs. Moreover, hsa-miR-6516-3p downregulated the expression of RECK, an endogenous inhibitor of MMP-9. However, in NHMCs, endogenous hsa-miR-6516-3p was not present in functional amounts under inflammatory environment; therefore, we performed analysis using an experimental system considering extracellular influences of mesangial cells under LNs. The expression of hsa-miR-6516-3p was increased in HUVECs under inflammatory conditions and in activated macrophages.

CONCLUSIONS

hsa-miR-6516-3p increases MMP9 expression by suppressing RECK, and might, thereby, exacerbate LNs.

Transepithelial transport of nanoparticles in oral drug delivery: From the perspective of surface and holistic property modulation

Despite the promising prospects of nanoparticles in oral drug delivery, the process of oral administration involves a complex transportation pathway that includes cellular uptake, intracellular trafficking, and exocytosis by intestinal epithelial cells, which are necessary steps for nanoparticles to enter the bloodstream and exert therapeutic effects. Current researchers have identified several crucial factors that regulate the interaction between nanoparticles and intestinal epithelial cells, including surface properties such as ligand modification, surface charge, hydrophilicity/hydrophobicity, intestinal protein corona formation, as well as holistic properties like particle size, shape, and rigidity. Understanding these properties is essential for enhancing transepithelial transport efficiency and designing effective oral drug delivery systems. Therefore, this review provides a comprehensive overview of the surface and holistic properties that influence the transepithelial transport of nanoparticles, elucidating the underlying principles governing their impact on transepithelial transport. The review also outlines the chosen of parameters to be considered for the subsequent design of oral drug delivery systems.

Circulating extracellular vesicles and small non-coding RNAs cargo in idiopathic inflammatory myopathies reveal differences across myositis subsets

OBJECTIVE

To investigate the epigenetic footprint of idiopathic inflammatory myopathies (IIM) through characterization of circulating extracellular vesicles (EVs) and the expression of EV-derived small non-coding RNAs (sncRNAs).

METHODS

In this cross-sectional study, EVs were isolated by size-exclusion chromatography from plasma of patients with IIM and age- and sex-matched healthy donors (HD). EV-derived sncRNAs were sequenced and quantified using Next-Generation Sequencing (NGS). Following quality control and normalization, filtered count reads were used for differential microRNA (miRNA) and piwi-interacting RNA (piRNA) expression analyses. Putative gene targets enriched for pathways implicated in IIM were analyzed. Patients' clinical and laboratory characteristics at the time of sampling were recorded.

RESULTS

Forty-seven IIM patients and 45 HD were enrolled. MiR-486-5p (p < 0.01), miR-122-5p, miR-192-5p, and miR-32-5p were significantly upregulated (p < 0.05 for all), while miR-142-3p (p < 0.001), miR-141-3p (p < 0.01), let-7a-5p (p < 0.05) and miR-3613-5p (p < 0.05) downregulated in EVs from IIM patients versus HD. MiR-486-5p was associated with raised muscle enzymes levels. Several target genes of up/downregulated miRNAs in IIM participate in inflammation, necroptosis, interferon and immune signaling. Six piRNAs were significantly dysregulated in IIM EVs versus HD (p < 0.05). Within IIM, miR-335-5p was selectively upregulated and miR-27a-5p downregulated in dermatomyositis (n = 21, p < 0.01). Finally, plasma EV levels were significantly increased in cancer-associated myositis (CAM, n = 12) versus non-CAM IIM (n = 35, p = 0.02) and HD (p < 0.01). EVs cargo in CAM was significantly enriched of let-7f-5p and depleted of miR-143-3p.

CONCLUSION

Through an unbiased screening of EV-derived sncRNAs, we characterize miRNAs and piRNAs in the EVs cargo as potential biomarkers and modifiers of diverse IIM phenotypes.

Sequence Alignment between TRIM33 Gene and Human Noncoding RNAs: A Potential Explanation for Paraneoplastic Dermatomyositis

BACKGROUND

This computational analysis investigated sequence complementarities between the TRIM33 gene and human noncoding (nc)RNAs and characterized their interactions in the context of paraneoplastic dermatomyositis.

METHODS

TRIM33 FASTA sequence (NCBI Reference Sequence: NC_000001.11) was used for BLASTN analysis against Human GRCh38 in the Ensembl.org database. Retrieved ncRNAs showing hits to TRIM33 were searched in the GeneCards.org database and further analyzed through RNAInter, QmRLFS-finder, Spliceator, and NcPath enrichment analysis.

RESULTS

A total of 100 hits were found, involving the lncRNAs NNT-AS1, MKLN1-AS, LINC01206, and PAXBP1-AS1, whose dysregulation has been reported in either cancer or dermatomyositis. Additionally, the lncRNAs NNT-AS1 and PAXBP1-AS1 may interact with microRNA-142-3p, reducing its expression and increasing that of TRIM33. Sequence complementarity affected only TRIM33 intron 1, possibly resulting in alternatively spliced isoforms of TIF1γ with increased immunogenicity. The results also revealed nucleotide alignment between TRIM33 and the gene regulatory elements of 28 ncRNA genes involved in immune pathways.

CONCLUSIONS

This pivotal study demonstrates sequence complementarity between TRIM33 and human ncRNAs dysregulated in cancer and dermatomyositis. This scenario may lead to the overproduction of more immunogenic TIF1γ variants in tumors and the stimulation of autoimmunity. Further experimental analyses using targeted methods such as Western blot or Chip-Seq are required to confirm these data.

Microarray analysis of microrna expression in peripheral blood mononuclear cells of patients with polymyositis and dermatomyositis

Background and Objectives

MicroRNAs (miRNAs) represent a new class of biomarkers in the context of connective tissue disorders. The miRNA expression profiles in peripheral blood mononuclear cells (PBMCs) of patients with polymyositis (PM) and dermatomyositis (DM) have not been fully elucidated. The objective is to investigate miRNAs expression profile in PBMCs of patients with PM/DM.

Methods

Microarray technology was used to identify differentially expressed miRNAs in PBMCs obtained from 6 untreated PM/DM patients and 3 healthy controls (HCs). TaqMan-based stem-loop real-time PCR detection was used for validation in a cohort of 34 PM/DM patients and 20 HCs.

Results

Microarray analysis revealed 38 differentially expressed miRNAs (24 up-regulated and 14 down-regulated) in PM/DM patients compared to HCs. Four miRNAs (miR-320a, miR-335-3p, miR-34a-5p and miR-454-3p) were chosen for real-time PCR validation. The expression of miR-34a-5p was significantly upregulated in PM/DM group (P < 0.05). In subgroup analysis, miR-34a-5p was significantly upregulated in interstitial lung disease (ILD) group and DM group (P < 0.001). The level of SIRT1, a validated target of miR-34a, was significantly lower in PBMCs of PM/DM patients compared with HCs.

Conclusions

MiR-34a-5p may potentially participate in the pathogenesis of PM/DM through SIRT1, and may serve as a potential new biomarker for PM/DM-ILD.

Autoimmune inflammatory myopathy biomarkers

The autoimmune inflammatory myopathy disease spectrum, commonly known as myositis, is a group of systemic diseases that mainly affect the muscles, skin and lungs. Biomarker assessment helps in understanding disease mechanisms, allowing for the implementation of precise strategies in the classification, diagnosis, and management of these diseases. This review examines the pathogenic mechanisms and highlights current data on blood and tissue biomarkers of autoimmune inflammatory myopathies.

Circulating miR-222-3p is associated with ankylosing spondylitis development and predicts therapeutic efficacy of nonsteroidal anti-inflammatory drugs

Ankylosing spondylitis (AS) is a chronic rheumatic disease, and some microRNAs (miRNAs) in AS have been identified. This study aimed to measure miR-222-3p expression in AS patients, investigate the association of miR-222-3p with AS disease activity, and explore the clinical value of miR-222-3p in diagnosing AS and predicting therapeutic efficacy of nonsteroidal anti-inflammatory drugs (NSAIDs) on AS patients. This study included 96 patients with AS, 58 patients with rheumatoid arthritis (RA), and 90 healthy controls. miR-222-3p expression was detected by reverse-transcription quantitative polymerase chain reaction (PCR). The ability of miR-222-3p to discriminate between different groups was evaluated by receiver operating characteristic analysis. The predictive value of miR-222-3p on the efficacy of NSAID treatment for AS was assessed by logistic regression analysis. AS patients treated with oral NSAIDs diclofenac sodium were divided into response (n = 76) and no-response (n = 20) groups after 16 weeks of treatment. miR-222-3p in AS patients was higher than that in healthy subjects and RA patients. miR-222-3p had high diagnostic value in distinguishing patients with AS from RA patients and healthy controls. miR-222-3p, increased in active AS patients, had the ability to screen active AS patients from inactive AS patients. miR-222-3p was decreased in the response group, and had high accuracy in predicting the therapeutic efficiency of NSAIDs. The findings indicate that increased miR-222-3p in AS patients may function as a diagnostic biomarker for AS, and predictive biomarker for the therapeutic efficacy of NSAIDs in patients with AS. In addition, miR-222-3p is associated with AS disease activity.

MicroRNAs in idiopathic inflammatory myopathies: state-of-the-art and future perspectives

PURPOSE OF REVIEW

Idiopathic inflammatory myopathies (IIMs) are a group of rare autoimmune disorders characterized by muscle weakness and inflammation. MicroRNAs (miRNAs) are the main class of small noncoding RNAs regulating a wide range of physiological and pathological processes and play a role in mediating autoimmunity and inflammation. In this review, we summarize the latest knowledge on the role of miRNAs in systemic autoimmune diseases with particular focus on IIMs.

RECENT FINDINGS

Study on miRNA expression in IIMs is helping in understanding the pathogenetic basis of the disease at a tissue and systemic level. Several miRNAs, even with a muscle-specific expression (myomiRs), have been shown to be involved in immune and nonimmune mechanisms of myofiber damage. MiRNAs modulate and orchestrate the local inflammatory infiltrate and could be used as potential biomarkers as they correlate with disease activity and response to therapy.

SUMMARY

IIMs comprise different clinical phenotypes and still little is known about the molecular signature of each subset. Further research about miRNA profiling will provide additional insights in the disease characterization with an expected impact on the therapeutic strategies.

Idiopathic inflammatory myopathy and non-coding RNA

Idiopathic inflammatory myopathies (IIMs) are common autoimmune diseases that affect skeletal muscle quality and function. The lack of an early diagnosis and treatment can lead to irreversible muscle damage. Non-coding RNAs (ncRNAs) play an important role in inflammatory transfer, muscle regeneration, differentiation, and regulation of specific antibody levels and pain in IIMs. ncRNAs can be detected in blood and hair; therefore, ncRNAs detection has great potential for diagnosing, preventing, and treating IIMs in conjunction with other methods. However, the specific roles and mechanisms underlying the regulation of IIMs and their subtypes remain unclear. Here, we review the mechanisms by which micro RNAs and long non-coding RNA-messenger RNA networks regulate IIMs to provide a basis for ncRNAs use as diagnostic tools and therapeutic targets for IIMs.

Serum-Circulating microRNAs in Sporadic Inclusion Body Myositis

BACKGROUND

Sporadic inclusion body myositis (s-IBM) represents a unique disease within idiopathic inflammatory myopathies with a dual myodegenerative-autoimmune physiopathology and a lack of an efficacious treatment. Circulating miRNA expression could expand our knowledge of s-IBM patho-mechanisms and provide new potential disease biomarkers. To evaluate the expression of selected pre-amplified miRNAs in the serum of s-IBM patients compared to those of a sex- and age-matched healthy control group, we enrolled 14 consecutive s-IBM patients and 8 sex- and age-matched healthy controls. By using two different normalization approaches, we found one downregulated and three upregulated miRNAs. hsa-miR-192-5p was significantly downregulated, while hsa-miR-372-3p was found to be upregulated more in the s-IBM patients compared to the level of the controls. The other two miRNAs had a very low expression levels (raw Ct data > 29). hsa-miR-192-5p and hsa-miR-372-3p were found to be significantly dysregulated in the serum of s-IBM patients. These miRNAs are involved in differentiation and regeneration processes, thus possibly reflecting pathological mechanisms in s-IBM muscles and potentially representing disease biomarkers.

Adult and juvenile dermatomyositis treatment

INTRODUCTION

Dermatomyositis is a rare autoimmune inflammatory condition affecting skin and muscles. The disease can be seen in both adults and children. It can be associated with malignancy. Considering involvement of skin in the disease, many patients consult dermatologists for its treatment. Hence, knowledge about its presentation, complications, prognosis, and treatment is necessary.

OBJECTIVE

The objective of this review article is to provide comprehensive information about treatment of dermatomyositis.

METHODS

In this review article, we reviewed the published literature on adult and juvenile dermatomyositis to highlight the treatment. Articles published in peer-reviewed journals including reviews, clinical trials, case series, and case reports published in electronic database (MEDLINE/PubMed) through January 2021, cross references of respective articles and trials from clinicaltrials.gov were included for qualitative analysis of the literature.

RESULTS

Treatment options for dermatomyositis include traditional immunosuppressive agents and immunomodulatory therapy. High-dose corticosteroids represent the first line of treatment while other immunosuppressive agents are also used, either in combination with or as an alternative to corticosteroids, after initial treatment failure. Some biological agents have been used for the treatment of dermatomyositis with variable responses.

CONCLUSION

Although several treatment options are available, several questions remain unanswered about the optimal treatment of dermatomyositis.

miR-208 inhibits myocardial tissues apoptosis in mice with acute myocardial infarction by targeting inhibition of PDCD4

This article aimed to investigate the role of miR-208 in the apoptosis of myocardial tissues in acute myocardial infarction (AMI) mice. The AMI mouse model was constructed. Then, miR-208 expression in AMI mice was regulated by transfection. The mouse myocardial tissues were subject to hematoxylin-eosin (HE) staining, TUNEL assay, and immunofluorescence analysis. H9c2 cell transfection and hypoxia induction were then completed, and cell apoptosis and cytokine levels were tested. Additionally, RNA pull-down and dual luciferase reporter gene assays were conducted for exploring the relation of miR-208 with programmed cell death 4 (PDCD4). Additionally, fluorescence in situ hybridization (FISH) was conducted for investigating miR-208 and PDCD4 colocalization within H9c2 cells. AMI mice had severe damage, apoptosis, decreased miR-208 expression, increased IL-1β, IL-6, IL-8 levels, whereas reduced IL-10 level within myocardial tissues. H9c2 cells under hypoxia induction exhibited decreased miR-208 expression, promoted apoptosis, increased protein expression of Bax and cleaved-caspase-3, decreased protein expression of Bcl-2 and caspase-3, elevated IL-1β, IL-6, IL-8 levels and decreased IL-10 level. miR-208 upregulation alleviated the damage and apoptosis of myocardial tissues in AMI mice. AMI mice with miR-208 upregulation showed decreased expression of Bax and cleaved-caspase-3, increased expression of Bcl-2 and caspase-3, reduced levels of IL-1β, IL-6, IL-8, whereas an increased level of IL-10. miR-208 showed direct inhibition of PDCD4. PDCD4 and miR-208 were mainly co-expressed in the cytoplasm. The upregulated PDCD4 expression abolished miR-208's suppression of H9c2 cell apoptosis induced by hypoxia. Besides this, miR-208 inhibited myocardial tissue apoptosis in AMI mice by inhibiting PDCD4 expression.

Plasma exosomal RNAs has potential as both clinical biomarkers and therapeutic targets of dermatomyositis

OBJECTIVES

Dermatomyositis (DM) is characterized by skeletal muscle weakness and cutaneous manifestations. Plasma exosomes (EXOs) contain proteins, RNAs, DNA, and lipid cargoes and are transferred among cells. Deeply investigated plasma EXO RNAs potentially improve our understanding of DM pathogenesis. We aimed to identify new potential biomarkers and therapeutic targets of DM.

METHODS

The RNAs (mRNA, miRNA and lncRNA) profiles of plasma EXOs were evaluated by sequencing on the Illumina HiSeq 3000 platform. Differentially expressed (DE) RNAs and bioinformatic analyses were performed. Human skeletal muscle myoblasts (HSkMCs) were stimulated with plasma EXOs, rapamycin or IFN-β. Real-time PCR and western blot were used to detect related genes and proteins.

RESULTS

A total of 689 DE mRNAs, 53 DE miRNAs and 452 DE lncRNAs were identified in DM plasma EXOs. Bioinformatic analysis inferred that plasma EXOs were secreted mainly by CD8+ T cells, regulatory T cells and natural killer cells. The DE miRNAs participated in the autophagy, TGF-β and Wnt signalling pathways. Three DE miRNAs (hsa-miR-125a-3p, hsa-miR-1246 and hsa-miR-3614-5p) were correlated with serological indices, organs involvement and myositis-specific autoantibodies. The DE lncRNAs participated in autophagy, interferon-β production and mTOR signalling. DM plasma EXOs can induce autophagy in HSkMCs by regulating 3 miRNAs (hsa-miR-125a-3p, hsa-miR-1246 and hsa-miR-3614-5p) and 3 lncRNAs (ENST00000584157.1, ENST00000523380.1, and ENST00000560054.1), which formed an autophagy network, playing the muscle damage roles.

CONCLUSIONS

Our study provides an overview of distinct RNAs profiles in DM plasma EXOs, and verified some miRNAs as potential biomarkers and therapeutic targets. The findings provide important clues for more in-depth explorations of plasma EXOs in DM.

Identification of Vital Hub Genes and Potential Molecular Pathways of Dermatomyositis by Bioinformatics Analysis

Dermatomyositis is an autoimmune disease characterized by severe symmetrical muscle dysfunction and pain. This study was aimed at discovering vital hub genes and potential molecular pathways of DM through bioinformatics analysis, which contributes to identifying potential diagnostic or therapeutic biomarkers and targets. In this study, a total of 915 DEGs in DM samples including 167 upregulated genes and 748 downregulated genes were screened out by the limma package based on the GSE142807 dataset from the Gene Expression Omnibus (GEO) database. Furthermore, the results of Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis indicated that these downregulated genes were highly associated with the immune-related biological processes and pathways. Therefore, 41 genes closely related to DM were extracted for further study based on the subcluster analysis through the Molecular Complex Detection (MCODE) software plugin in Cytoscape. Ultimately, 10 hub genes (including ISG15, DDX58, IFIT3, CXCL10, and STAT1) were identified as the potential candidate biomarkers and targets. Besides, we found that the identified hub genes directly or indirectly communicated with each other via molecular signaling pathways on the protein and transcription level. In general, under the guidance of bioinformatics analysis, 10 vital hub genes and molecular mechanisms in DM were identified and the expression of proinflammatory factors and interferon family proteins and genes showed high association with DM, which might help provide a theoretical foundation for the development of point-to-point targeted therapy in the future treatment of DM.

Cytokines and inflammatory mediators as promising markers of polymyositis/dermatomyositis

PURPOSE OF REVIEW

Idiopathic inflammatory myopathies (IIMs), known also as myositis, represent challenging group of heterogeneous muscle disorders characterized by symmetric proximal muscle weakness and evidence of muscle inflammation. The purpose of this review is to provide important updates on cytokines and inflammatory mediators related to myositis.

RECENT FINDINGS

In the past 5 years, multiple studies brought a fresh insight into the pathogenesis of myositis by introducing new factors or further characterizing the role of the well established mediators in myositis. Among the mediators reviewed in this article, special attention was paid to interferons, C-X-C motif chemokine ligand 10, interleukin-18 and the IL23/Th17 axis. Some of the recent work has also focused on the nontraditional cytokines, such as adipokines, myokines, S100 proteins, High Mobility Group Box 1 or B-cell activating factor and on several anti-inflammatory mediators. Moreover, microRNAs and their potential to reflect the disease activity or to regulate the inflammatory processes in myositis have recently been subject of intensive investigation. Some of the above-mentioned mediators have been proposed as promising clinical biomarkers or therapeutic targets for myositis.

SUMMARY

Several recent studies contributed to a better understanding of the pathogenesis of myositis and highlighted the clinical significance of certain inflammatory mediators. Application of these new findings may help to develop innovative approaches for patients' phenotyping, disease activity monitoring and potentially novel therapies.

Polishing the crystal ball: mining multi-omics data in dermatomyositis

Precision medicine, which recognizes and upholds the uniqueness of each individual patient and the importance of discerning these inter-individual differences on a molecular scale in order to provide truly personalized medical care, is a revolutionary approach that relies on the discovery of clinically-relevant biomarkers derived from the massive amounts of data generated by epigenomic, genomic, transcriptomic, proteomic, microbiomic, and metabolomic studies, collectively known as multi-omics. If harnessed and mined appropriately with the help of ever-evolving computational and analytic methods, the collective data from omics studies has the potential to accelerate delivery of targeted medical treatment that maximizes benefit, minimizes harm, and eliminates the “fortune-telling” inextricably linked to the prevailing trial-and-error approach. For a disease such as dermatomyositis (DM), which is characterized by remarkable phenotypic heterogeneity and varying degrees of multi-organ involvement, an individualized approach that incorporates big data derived from multi-omics studies with the results of currently available serologic, histopathologic, radiologic, and electrophysiologic tests, and, most importantly, with clinical findings obtained from a thorough history and physical examination, has immense diagnostic, therapeutic, and prognostic value. In this review, we discuss omics-based research studies in DM and describe their practical applications and promising roles in guiding clinical decisions and optimizing patient outcomes.

Identification and Characterization of Serum microRNAs as Biomarkers for Human Disc Degeneration: An RNA Sequencing Analysis

Circulating microRNAs (miRNAs) have been associated with various degenerative diseases, including intervertebral disc (IVD) degeneration. Lumbar disc herniation (LDH) often occurs in young patients, although the underlying mechanisms are poorly understood. The aim of this work was to generate RNA deep sequencing data of peripheral blood samples from patients suffering from LDH, identify circulating miRNAs, and analyze them using bioinformatics applications. Serum was collected from 10 patients with LDH (Disc Degeneration Group); 10 patients without LDH served as the Control Group. RNA sequencing analysis identified 73 differential circulating miRNAs (p < 0.05) between the Disc Degeneration Group and Control Group. Gene ontology enrichment analysis (p < 0.05) showed that these differentially expressed miRNAs were associated with extracellular matrix, damage reactions, inflammatory reactions, and regulation of apoptosis. Kyoto Encyclopedia of Genes and Genomes analysis showed that the differentially expressed genes were involved in diverse signaling pathways. The profile of miR-766-3p, miR-6749-3p, and miR-4632-5p serum miRNAs was significantly enriched (p < 0.05) in multiple pathways associated with IVD degeneration. miR-766-3p, miR-6749-3p, and miR-4632-5p signature from serum may serve as a noninvasive diagnostic biomarker for LHD manifestation of IVD degeneration. Furthermore, several dysregulated miRNAs may be involved in the pathogenesis of IVD degeneration. Further study is needed to confirm the functional role of the identified miRNAs.

Influence of microRNAs and exosomes in muscle health and diseases

microRNAs are short, (18-22 nt) non-coding RNAs involved in important cellular processes due to their ability to regulate gene expression at the post-transcriptional level. Exosomes are small (50-200 nm) extracellular vesicles, naturally secreted from a variety of living cells and are believed to mediate cell-cell communication through multiple mechanisms, including uptake in destination cells. Circulating microRNAs and exosome-derived microRNAs can have key roles in regulating muscle cell development and differentiation. Several microRNAs are highly expressed in muscle and their regulation is important for myocyte homeostasis. Changes in muscle associated microRNA expression are associated with muscular diseases including muscular dystrophies, inflammatory myopathies, and congenital myopathies. In this review, we aim to highlight the biology of microRNAs and exosomes as well as their roles in muscle health and diseases. We also discuss the potential crosstalk between skeletal and cardiac muscle through exosomes and their contents.

Altered dynamics of lipid metabolism in muscle cells from patients with idiopathic inflammatory myopathy is ameliorated by 6 months of training

KEY POINTS

Regular exercise improves muscle functional capacity and clinical state of patients with idiopathic inflammatory myopathy (IIM). In our study, we used an in vitro model of human primary muscle cell cultures, derived from IIM patients before and after a 6-month intensive supervised training intervention to assess the impact of disease and exercise on lipid metabolism dynamics. We provide evidence that muscle cells from IIM patients display altered dynamics of lipid metabolism and impaired adaptive response to saturated fatty acid load compared to healthy controls. A 6-month intensive supervised exercise training intervention in patients with IIM mitigated disease effects in their cultured muscle cells, improving or normalizing their capacity to handle lipids. These findings highlight the putative role of intrinsic metabolic defects of skeletal muscle in the pathogenesis of IIM and the positive impact of exercise, maintained in vitro by yet unknown epigenetic mechanisms.

ABSTRACT

Exercise improves skeletal muscle function, clinical state and quality of life in patients with idiopathic inflammatory myopathy (IIM). Our aim was to identify disease-related metabolic perturbations and the impact of exercise in skeletal muscle cells of IIM patients. Patients underwent a 6-month intensive supervised training intervention. Muscle function, anthropometric and metabolic parameters were examined and muscle cell cultures were established (m. vastus lateralis; Bergström needle biopsy) before and after training from patients and sedentary age/sex/body mass index-matched controls. [¹⁴ C]Palmitate was used to determine fat oxidation and lipid synthesis (thin layer chromatography). Cells were exposed to a chronic (3 days) and acute (3 h) metabolic challenge (the saturated fatty acid palmitate, 100 μm). Reduced oxidative (intermediate metabolites, -49%, P = 0.034) and non-oxidative (diglycerides, -38%, P = 0.013) lipid metabolism was identified in palmitate-treated muscle cells from IIM patients compared to controls. Three days of palmitate exposure elicited distinct regulation of oxidative phosphorylation (OxPHOS) complex IV and complex V/ATP synthase (P = 0.012/0.005) and adipose triglyceride lipase in patients compared to controls (P = 0.045) (immunoblotting). Importantly, 6 months of training in IIM patients improved lipid metabolism (CO₂ , P = 0.010; intermediate metabolites, P = 0.041) and activation of AMP kinase (P = 0.007), and nearly normalized palmitate-induced changes in OxPHOS proteins in myotubes from IIM patients, in parallel with improvements of patients' clinical state. Myotubes from IIM patients displayed altered dynamics of lipid metabolism and impaired response to metabolic challenge with saturated fatty acid. Our observations suggest that metabolic defects intrinsic to skeletal muscle could represent non-immune pathomechanisms, which can contribute to muscle weakness in IIM. A 6-month training intervention mitigated disease effects in muscle cells in vitro, indicating the existence of epigenetic regulatory mechanisms.

Reduced miR-146a Promotes REG3A Expression and Macrophage Migration in Polymyositis and Dermatomyositis

Background: Growing evidence from studies elsewhere have illustrated that microRNAs (miRNAs) play important roles in polymyositis and dermatomyositis (PM/DM). However, little has been reported on their relationship with regenerating islet-derived protein 3-alpha (REG3A) as well as their associative roles in macrophage migration. Therefore, this study sought to establish the association between miR-146a and REG3A as well as investigate their functional roles in macrophage migration and PM/DM pathogenesis. Methods: Peripheral blood mononuclear cells (PBMCs) were isolated from PM/DM patients and healthy controls through density centrifugation. Macrophages were obtained from monocytes purified from PBMCs via differentiation before their transfection with miRNA or plasmids to investigate cell migration with transwell assay. An experimental autoimmune myositis murine model was used to investigate PM/DM. Real-time PCR and Western blot analysis were conducted to determine the expression levels of miR-146a, interferon gamma (IFN-γ), interleukin (IL)-17A, and REG3A. Results: The messenger RNA (mRNA) expression level of miR-146a markedly decreased, while the mRNA level of REG3A, IFN-γ, and IL-17A expression increased substantially in PBMCs from PM/DM patients compared with the healthy controls. The levels of IFN-γ and IL-17A in serum from PM/DM patients was much higher than the healthy controls. Immunohistochemistry analysis showed that REG3A expression increased in muscle tissues from patients. Consistent with clinical data, the mRNA expression level of miR-146a also decreased, whereas the mRNA and protein level of REG3A, IFN-γ, and IL-17A significantly increased in the muscle tissues of experimental autoimmune myositis mice. Moreover, miR-146a inhibited monocyte-derived macrophage migration, and REG3A promoted macrophage migration. In addition, IL-17A induced REG3A expression, while miR146a inhibited expression of REG3A in monocyte-derived macrophages from the PBMCs of the healthy donors. Notably, inhibition of macrophage migration by miR-146a was via the reduction in REG3A expression. Conclusions: Reduced miR-146a expression in PM/DM leads to increased REG3A expression that increases inflammatory macrophage migration, which may be a possible underlying mechanism of DM/PM pathogenesis.

Identifying the culprits in neurological autoimmune diseases

The target organ of neurological autoimmune diseases (NADs) is the central or peripheral nervous system. Multiple sclerosis (MS) is the most common NAD, whereas Guillain-Barré syndrome (GBS), myasthenia gravis (MG), and neuromyelitis optica (NMO) are less common NADs, but the incidence of these diseases has increased exponentially in the last few years. The identification of a specific culprit in NADs is challenging since a myriad of triggering factors interplay with each other to cause an autoimmune response. Among the factors that have been associated with NADs are genetic susceptibility, epigenetic mechanisms, and environmental factors such as infection, microbiota, vitamins, etc. This review focuses on the most studied culprits as well as the mechanisms used by these to trigger NADs.

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Neurological autoimmune diseases are caused by a complex interaction between genes, environmental factors, and epigenetic deregulation.

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Infectious agents can cause an autoimmune reaction to myelin epitopes through molecular mimicry and/or bystander activation.

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Gut microbiota dysbiosis contributes to neurological autoimmune diseases.

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Smoking increases the risk of NADs through inflammatory signaling pathways, oxidative stress, and Th17 differentiation.

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Deficiency in vitamin D favors NAD development through direct damage to the central and peripheral nervous system.

The function of ncRNAs in rheumatic diseases

Rheumatic diseases are a group of chronic heterogeneous autoimmune disorders characterized by abnormal regulation of the innate and adaptive immune systems. Despite extensive efforts, the full spectrum of molecular factors that contribute to the pathogenesis of rheumatic diseases remains unclear. ncRNAs can govern gene expression at the transcriptional and post-transcriptional levels in multiple diseases. Recent studies have demonstrated an important role for ncRNAs, such as miRNAs and lncRNAs, in the development of immune cells and rheumatic diseases. Here, we focus on the epigenetic regulatory roles of ncRNAs in the pathogenesis of rheumatic diseases and as biomarkers of disease state.

Dysregulated expression profile of myomiRs in the skeletal muscle of patients with polymyositis

MicroRNA (miRNA) research has intensively developed over the past decade. Characterization of dysregulated miRNA expression profiles could give a better understanding of the development of pathological conditions and clinical disorders, such as autoimmune diseases with polygenic etiology, including idiopathic inflammatory myopathies (IIMs). IIMs are a group of rare autoimmune disorders characterized by skeletal weakness and inflammation. Polymyositis (PM) is one of the conditions of autoimmune myopathies with proximal skeletal muscle weakness. A novel group of miRNAs, known as myomiRs are described as striated muscle-specific or muscle-enriched miRNAs. They are involved in myoblast proliferation/differentiation as well as muscle regeneration. To determine the role of myomiRs in the development and progression of PM, we performed an initial skeletal muscle miRNA profiling using microarray technique at diagnosis. The aim of the study was to examine myomiRs expression profile in patients with PM in order to remark the association between the dysregulated myomiRs' expression and the development of the disease. As a results of microarray investigation, most of the myomiRs showed altered expression patterns in the muscle samples of PM patients compared to controls. These results suggest that myomiRs, especially miR-1, miR-133a, miR-208b, miR-486, and miR-499 function in a network, and are associated with the development of PM.

[Advances in epigenetic markers of dermatomyositis/polymyositis]

Idiopathic inflammatory myopathy (IIM) is a rare group of autoimmune diseases, characterized by chronic muscle weakness, muscle fatigue and infiltration of single nuclear cells in skeletal muscle. Its subtypes include dermatomyositis (DM), polymyositis (PM), inclusion body myositis (IBM) and immune-mediated necrotizing myositis (IMNM), and the most common subtypes are DM and PM. PM is an autoimmune disease mainly manifested by muscle damage. When the skin is involved, it is called DM. The incidence of IIM was relatively low, which was 1.16-19 per million people/year, but the mortality was high and the prognosis was poor. The pathogenesis of IIM is still unclear. Previous studies suggest that both immune and non-immune mechanisms are involved in its pathogenesis, especially cellular and humoral immunity. In recent years, researchers have conducted a number of studies on the pathogenesis of IIM, especially in the study of DM/PM with the application of high-throughput biometrics. Epigenetics is a discipline that refers to the genetic phenomena of DNA methylation spectrum, chromatin structure state and gene expression spectrum transferred between cells without any changes in DNA sequence, including DNA methylation, chromatin modification and non-coding RNA changes. A large number of studies have shown that epigenetic modification plays an important role in many diseases, especially in cancer. Recent studies have also found a series of epigenetic markers related to the occurrence and development of DM/PM, mainly in the aspect of non-coding RNA changes, such as miR-10a, miR-206, etc. And there has also been some research on DNA methylation. However, no studies have been reported on whether chromatin modification is involved in the pathogenesis of DM/PM. The pathogenesis of DM/PM is complex and diverse. With the development of research, certain microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) may become biological markers for the early diagnosis of DM/PM. Therefore, this paper mainly expounds the research progress of the biomarkers of DM/PM from the aspect of epigenetics.

[Advances in epigenetic markers of dermatomyositis/polymyositis]

Idiopathic inflammatory myopathy (IIM) is a rare group of autoimmune diseases, characterized by chronic muscle weakness, muscle fatigue and infiltration of single nuclear cells in skeletal muscle. Its subtypes include dermatomyositis (DM), polymyositis (PM), inclusion body myositis (IBM) and immune-mediated necrotizing myositis (IMNM), and the most common subtypes are DM and PM. PM is an autoimmune disease mainly manifested by muscle damage. When the skin is involved, it is called DM. The incidence of IIM was relatively low, which was 1.16-19 per million people/year, but the mortality was high and the prognosis was poor. The pathogenesis of IIM is still unclear. Previous studies suggest that both immune and non-immune mechanisms are involved in its pathogenesis, especially cellular and humoral immunity. In recent years, researchers have conducted a number of studies on the pathogenesis of IIM, especially in the study of DM/PM with the application of high-throughput biometrics. Epigenetics is a discipline that refers to the genetic phenomena of DNA methylation spectrum, chromatin structure state and gene expression spectrum transferred between cells without any changes in DNA sequence, including DNA methylation, chromatin modification and non-coding RNA changes. A large number of studies have shown that epigenetic modification plays an important role in many diseases, especially in cancer. Recent studies have also found a series of epigenetic markers related to the occurrence and development of DM/PM, mainly in the aspect of non-coding RNA changes, such as miR-10a, miR-206, etc. And there has also been some research on DNA methylation. However, no studies have been reported on whether chromatin modification is involved in the pathogenesis of DM/PM. The pathogenesis of DM/PM is complex and diverse. With the development of research, certain microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) may become biological markers for the early diagnosis of DM/PM. Therefore, this paper mainly expounds the research progress of the biomarkers of DM/PM from the aspect of epigenetics.

Specific Autoantibodies and Clinical Phenotypes Correlate with the Aberrant Expression of Immune-Related MicroRNAs in Dermatomyositis

Aims

The serum concentrations of miRNAs, miR-23a-3p, miR-23b-3p, miR-146a-5p, miR-146b-5p, and miR-150-5p, were shown to be associated with the immune and inflammatory progressions. We assessed the expressions of these five miRNAs in association with clinical phenotypes and myositis-specific autoantibody-defined subgroups of dermatomyositis (DM).

Methods

The present study included 49 patients with DM and 30 healthy controls. The serum concentrations of miR-23a-3p, miR-23b-3p, miR-146a-5p, miR-146b-5p, and miR-150-5p were measured by quantitative reverse transcription polymerase chain reaction (qRT-PCR). Associations between the serum concentrations of miRNAs and DM clinical immune phenotypes were examined as well.

Results

The serum concentrations of miR-23b-3p, miR-146a-5p, and miR-150-5p were significantly downregulated in DM patients (P < 0.001, P < 0.001, and P = 0.002, respectively), while miR-146b-5p was remarkably upregulated in DM patients compared with healthy controls (P = 0.039). Similarly, the expressions of miR-23b-3p, miR-146a-5p, and miR-150-5p were significantly downregulated in the peripheral blood mononuclear cells (PBMCs) from DM patients. Further study indicated that the serum level of miR-23b-3p was significantly correlated with creatine kinase (CK) (r = −0.286, P = 0.046) and the serum level of miR-146a-5p was evidently correlated with C-reactive protein (CRP) (r = −0.358, P = 0.012). Significant correlations were also observed between the serum levels of miR-146b-5p and CRP (r = −0.347, P = 0.014) and the erythrocyte sedimentation rate (ESR) (r = −0.287, P = 0.046). In addition, the expression level of miR-146b-5p was upregulated in DM complicated by tumors compared with those without tumors (P = 0.001 and P < 0.001, respectively). Especially, miR-150-5p was significantly downregulated in DM patients with anti-MDA5 antibodies and anti-NXP2 antibodies compared with those without (P = 0.017 and P = 0.047, respectively). No significant differences were observed between the four serum microRNAs in patients with and without interstitial lung diseases (all P > 0.05).

Conclusion

The results suggest an association between the four immune-related microRNAs and different clinical immune-phenotypes, and this association may regulate the complexity of disease processes through multipathways in DM patients.

MicroRNA-766-3p Contributes to Anti-Inflammatory Responses through the Indirect Inhibition of NF-κB Signaling

MicroRNA (miRNA) is small RNA of 20 to 22 nucleotides in length and is stably present in plasma. Regulating the expression of miRNA taken into cells has been suggested as a general therapeutic approach. We identified the novel anti-inflammatory miRNA hsa-miR-766-3p and investigated its biological function in human rheumatoid arthritis (RA) fibroblast-like synoviocyte MH7A cells. To verify the function of the miRNA present in the plasma of RA patients, we performed a comprehensive analysis of the miRNA expression during abatacept treatment and identified eight miRNAs with significantly altered expression levels. Among these eight miRNAs, miR-766-3p was found to have a clear function. The expression of inflammatory genes in response to inflammatory stimuli was suppressed in MH7A transduced with miR-766-3p. We showed that miR-766-3p indirectly reduced the activation of NF-κB and clarified that this mechanism was partially involved in the reduction of the mineralocorticoid receptor expression. In addition, the inflammatory responses were suppressed in other types of cells. These results indicate the novel function of miR-766-3p, findings that may aid in the development of therapies to suppress inflammation, not only in RA but also in other diseases.

MiR-5571-3p and miR-135b-5p, derived from analyses of microRNA profile sequencing, correlate with increased disease risk and activity of rheumatoid arthritis

OBJECTIVES

This study aimed to investigate microRNA (miRNA) expression profiles in synovium tissues of rheumatoid arthritis (RA) patients by RNA sequencing and to evaluate the values of dysregulated miRNAs in RA diagnosis and monitoring.

METHODS

Thirty RA patients who underwent knee arthroscopy and 30 controls with knee trauma who underwent surgery were consecutively recruited, and synovium tissue samples of both groups were obtained during surgeries. In the exploration part, miRNA and mRNA expression profiles of 3 RA samples and 3 control samples were detected using RNA sequencing then followed by bioinformatic analyses. In the validation part, 5 candidate miRNA levels were detected by quantitative polymerase chain reaction (qPCR) in 30 RA patients and 30 control patients.

RESULTS

In the exploration part, 78 miRNAs and 1582 mRNAs were upregulated while 40 miRNAs and 1295 mRNAs were downregulated in synovium tissue samples of RA patients compared with those of controls. Furthermore, enrichment analyses revealed that these dysregulated miRNAs and mRNAs were mainly implicated in immune activities and inflammatory diseases such as leukocyte migration, complement activation, and RA. In the validation part, qPCR assay revealed that miR-5571-3p and miR-135b-5p expressions were increased in RA patients compared with those in controls and disclosed good predictive values for RA risk with high area under the curves (AUCs). Besides, both miR-5571-3p and miR-135b-5p levels were positively correlated with disease activity and inflammation level of RA.

CONCLUSIONS

Analyses of miRNA expression profiles by sequencing indicate that miR-5571-3p and miR-135b-5p correlate with increased RA risk and activity.

MicroRNAs as biological regulators in skin disorders

microRNAs are being investigated as promising therapeutic targets and biomarkers for different disease conditions. miRNAs serve as essential regulators of cell differentiation, proliferation and survival. The involvement of miRNAs in the functioning and regulation of the skin cells and skin diseases is a rapidly advancing area in dermatological research. miRNAs have been identified to play a key role in the pathogenesis, diagnosis, and treatment of the skin diseases. Skin is one of the largest organs of the body, primarily functioning as the first line of defence against external insults including bacteria, virus and other pathogens. Various miRNAs have been identified to demonstrate significant effects in various skin inflammatory conditions such as wounds, cancer, psoriasis, scleroderma, dermatomyositis. The current review explores the possible roles of the miRNAs in skin disorders and reports relating to the clinical trials involving skin diseases and miRNAs. The review has also compiled the information of the databases available, which correlates the miRNAs with different diseases and give details about targeting interactions of miRNA.

Dysregulation of microRNAs in autoimmune diseases: Pathogenesis, biomarkers and potential therapeutic targets

MicroRNAs (miRNAs) are small, single-stranded, endogenous non-coding RNAs that repress the expression of target genes via post-transcriptional mechanisms. Due to their broad regulatory effects, the precisely regulated, spatial-specific and temporal-specific expression of miRNAs is fundamentally important to various biological processes including the immune homeostasis and normal function of both innate and adaptive immune response. Aberrance of miRNAs is implicated in the development of various human diseases, especially cancers. Increasing evidence has revealed a dysregulated expression pattern of miRNAs in autoimmune diseases, among which many play key roles in the pathogenesis. In this review we summarize these findings on miRNA dysregulation implicated in autoimmune diseases, focusing on four representative systemic autoimmune diseases, i.e. systemic lupus erythematosus, rheumatoid arthritis, systemic sclerosis and dermatomyositis. The causes of the dysregulation of miRNA expression in autoimmune diseases may include genetic and epigenetic variants, and various environmental factors. Further understanding of miRNA dysregulation and its mechanisms during the development of different autoimmune diseases holds enormous potential to bring about novel therapeutic targets or strategies for these complex human disorders, as well as novel circulating or exosomal miRNA biomarkers.