MiR-146a mediates TLR-4 signaling pathway to affect myocardial fibrosis in rat constrictive pericarditis model

Comprehensive bioinformatics analysis and systems biology approaches to identify the interplay between COVID-19 and pericarditis

Background

Increasing evidence indicating that coronavirus disease 2019 (COVID-19) increased the incidence and related risks of pericarditis and whether COVID-19 vaccine is related to pericarditis has triggered research and discussion. However, mechanisms behind the link between COVID-19 and pericarditis are still unknown. The objective of this study was to further elucidate the molecular mechanisms of COVID-19 with pericarditis at the gene level using bioinformatics analysis.

Methods

Genes associated with COVID-19 and pericarditis were collected from databases using limited screening criteria and intersected to identify the common genes of COVID-19 and pericarditis. Subsequently, gene ontology, pathway enrichment, protein-protein interaction, and immune infiltration analyses were conducted. Finally, TF-gene, gene-miRNA, gene-disease, protein-chemical, and protein-drug interaction networks were constructed based on hub gene identification.

Results

A total of 313 common genes were selected, and enrichment analyses were performed to determine their biological functions and signaling pathways. Eight hub genes (IL-1β, CD8A, IL-10, CD4, IL-6, TLR4, CCL2, and PTPRC) were identified using the protein-protein interaction network, and immune infiltration analysis was then carried out to examine the functional relationship between the eight hub genes and immune cells as well as changes in immune cells in disease. Transcription factors, miRNAs, diseases, chemicals, and drugs with high correlation with hub genes were predicted using bioinformatics analysis.

Conclusions

This study revealed a common gene interaction network between COVID-19 and pericarditis. The screened functional pathways, hub genes, potential compounds, and drugs provided new insights for further research on COVID-19 associated with pericarditis.

miR-92b-5p negatively regulates IKK through targeting its ORF region in the innate immune responses of amphioxus (Branchiostoma belcheri)

Cephalochordate (Amphioxus), situated at a key phylogenetic position in the phylum Chordata, serves as a model organism for studying the origin and evolution of the vertebrate innate immune. In this study, five members of precursor miR-92 family (miR-92a-1, miR-92a-2, miR-92b, miR-92c and miR-92d) are identified in Branchiostoma belcheri, and their evolutionary conservation and potential molecular functions in innate immunity are analyzed. Among them, miR-92b-5p was validated in HEK293 cells to target the coding region but not classic 3'UTR of IKK (inhibitor of nuclear factor kappa-B kinase) mRNA, one integral component of MAPK and TLR4 immune signaling. Furthermore, the spatiotemporal expression patterns of miR-92b-5p and IKK were examined in different tissues or different time points (2 h, 4 h, 8 h, 12 h, 24 h and 48 h) post LPS stimulation at RNA and protein level in vivo. The seemingly inverse expression pattern between miR-92b-5p and IKK supports the involvement of miR-92b-5p in Branchiostoma belcheri innate immune response. In conclusion, our work not only illustrates the evolutionary pattern of Branchiostoma belcheri miR-92 family across chordates, but also reveals that miR-92b-5p could target IKK expression to regulate innate immune response.

MicroRNAs (miRNAs) in Cardiovascular Complications of Rheumatoid Arthritis (RA): What Is New?

Rheumatoid Arthritis (RA) is among the most prevalent and impactful rheumatologic chronic autoimmune diseases (AIDs) worldwide. Within a framework that recognizes both immunological activation and inflammatory pathways, the exact cause of RA remains unclear. It seems however, that RA is initiated by a combination between genetic susceptibility, and environmental triggers, which result in an auto-perpetuating process. The subsequently, systemic inflammation associated with RA is linked with a variety of extra-articular comorbidities, including cardiovascular disease (CVD), resulting in increased mortality and morbidity. Hitherto, vast evidence demonstrated the key role of non-coding RNAs such as microRNAs (miRNAs) in RA, and in RA-CVD related complications. In this descriptive review, we aim to highlight the specific role of miRNAs in autoimmune processes, explicitly on their regulatory roles in the pathogenesis of RA, and its CV consequences, their main role as novel biomarkers, and their possible role as therapeutic targets.

MicroRNA targets and biomarker validation for diabetes-associated cardiac fibrosis

Cardiac fibrosis is one of the main characteristics of diabetic cardiomyopathy and manifests excessive accumulation of extracellular matrix proteins in the heart. Several signaling pathways have been proposed for pathogenesis of cardiac fibrosis in the diabetic heart. TGF-β/Smad2/3-dependent or independent pathway is the major signaling molecule core in the pathogenesis of cardiac fibrosis. MicroRNAs (miRNAs, miR) are ~22-nuceotide regulatory RNAs that are involved in gene silencing through the degradation of post-transcriptional mRNA or suppression of the expressed proteins. Hyperglycemia in the diabetic heart regulates expression of some miRNAs. Target molecules of miRNAs can be identified through biocomputational database initial screening and dual luciferase assay validation. miR-21, miR-150-5p, miR-155, miR-216a-3p, miR-221-3p, miR-223, and miR-451 were up-regulated in the diabetic heart and promoted cardiac fibrosis through targeting signaling pathways in cardiac fibroblasts, endothelial cells, and cardiac myocytes. miR-15a/-15b, miR-18a-5p, miR-20a-5p, miR-26b-5p, miR-29, miR-133a, miR-141, miR-146, miR-200b, miR-203, miR-222, and miR-551b-5p were down-regulated in the diabetic heart and exhibited anti-fibrosis when they were overexpressed. miRNAs are stable molecules and may reflect the pathological changes of organs. Some miRNAs have been detected in the plasma or serum in patients with diabetes mellitus or heart failure. Exploration of targets and biomarkers of miRNA may provide additional information on pathogenesis and diagnosis of cardiac fibrosis and novel targets to tackle diabetic cardiomyopathy.

miRNA-146a Mimic Inhibits NOX4/P38 Signalling to Ameliorate Mouse Myocardial Ischaemia Reperfusion (I/R) Injury

Evidence suggests that miR-146a is implicated in the pathogenesis of cardiovascular diseases; however, the role of miR-146a in myocardial ischaemia reperfusion (I/R) injury is unclear. The aim of this study was to explore the functional role of miR-146a in myocardial ischaemia reperfusion injury and the underlying mechanism. C57BL/6J mice were subjected to 45 min of ischaemia and 1 week of reperfusion to establish a myocardial I/R injury model. A miR-146a mimic (0.5 mg/kg) was administered intravenously at the beginning of the ischaemia process. Neonatal rat cardiomyocytes were also subjected to hypoxia/reperfusion (H/R). Cells were treated with the miR-146a mimic or antagonist. As a result, the miR-146a mimic attenuated H/R-induced cardiomyocyte injury, as evidenced by increased cell viability and reduced lactate dehydrogenase (LDH) levels. In addition, the miR-146a mimic inhibited oxidative stress in cells suffering from H/R injury. Moreover, the miR-146a antagonist exerted adverse effects in vitro. In mice with myocardial I/R injury, the miR-146a mimic preserved cardiac function and reduced the infarction area and fibrosis. Moreover, the miR-146a mimic decreased the inflammatory response and reactive oxygen species (ROS) accumulation in mouse hearts. Mechanistically, we found that miR-146a directly regulated the transcription of NOX4, which subsequently affected P38 signalling in cardiomyocytes. When we knocked down NOX4, the effects of the miR-146a antagonist in worsening the cell condition were counteracted in in vitro experiments. Taken together, the results suggest that miR-146a protects against myocardial ischaemia reperfusion injury by inhibiting NOX4 signalling. The miR-146a mimic may become a potential therapeutic approach for patients with myocardial ischaemia reperfusion.