Background Extracellular vesicles (EVs) are mediators of cell-to-cell communication in inflammatory lung diseases. They function as carriers for miRNAs which regulate mRNA transcripts and signaling pathways after uptake into recipient cells. We investigated whether miRNAs associated with circulating EVs regulate immunologic processes in COVID-19. Methods We prospectively studied 20 symptomatic patients with COVID-19 pneumonia, 20 mechanically ventilated patients with severe COVID-19 (severe acute respiratory corona virus-2 syndrome, ARDS) and 20 healthy controls. EVs were isolated by precipitation, total RNA was extracted, profiled by small RNA sequencing and evaluated by differential gene expression analysis (DGE). Differentially regulated miRNAs between groups were bioinformatically analyzed, mRNA target transcripts identified and signaling networks constructed, thereby comparing COVID-19 pneumonia to the healthy state and pneumonia to severe COVID-19 ARDS. Results DGE revealed 43 significantly and differentially expressed miRNAs (25 downregulated) in COVID-19 pneumonia when compared to controls, and 20 miRNAs (15 downregulated) in COVID-19 ARDS patients in comparison to those with COVID-19 pneumonia. Network analysis for comparison of COVID-19 pneumonia to healthy controls showed upregulated miR-3168 (log2FC=2.28, p adjusted <0.001), among others, targeting interleukin-6 (IL6) (25.1, 15.2 - 88.2 pg/ml in COVID-19 pneumonia) and OR52N2, an olfactory smell receptor in the nasal epithelium. In contrast, miR-3168 was significantly downregulated in COVID-19 ARDS (log2FC=-2.13, p adjusted =0.003) and targeted interleukin-8 (CXCL8) in a completely activated network. Toll-like receptor 4 (TLR4) was inhibited in COVID-19 pneumonia by miR-146a-5p and upregulated in ARDS by let-7e-5p. Conclusion EV-derived miRNAs might have important regulative functions in the pathophysiology of COVID-19: CXCL8 regulates neutrophil recruitment into the lung causing epithelial damage whereas activated TLR4, to which SARS-CoV-2 spike protein binds strongly, increases cell surface ACE2 expression and destroys type II alveolar cells that secrete pulmonary surfactants; both resulting in pulmonary-capillary leakage and ARDS. These miRNAs may serve as biomarkers or as possible therapeutic targets.
【저자키워드】 COVID-19, ARDS, Sepsis, Extracellular vesicles, community acquired pneumonia, Severe Acute Respiratory Corona Virus-2 Syndrome, small RNA sequencing, cell-free microRNAs, 【초록키워드】 ARDS, COVID-19 pneumonia, Biomarker, Biomarkers, severe COVID-19, Pneumonia, TLR4, neutrophil, miRNA, interleukin-8, interleukin-6, IL6, lung, Toll-like receptor, Spike protein, interleukin, miRNAs, pathophysiology, cells, mRNA, SARS-CoV-2 spike protein, RNA sequencing, Lung diseases, small RNA, network analysis, network, toll-like receptor 4, signaling pathway, receptor, respiratory, group, ACE2 expression, epithelial, function, therapeutic targets, CXCL8, Signaling, Differential gene expression, Analysis, Inflammatory, regulate, Pathways, Precipitation, olfactory, mediators, among others, healthy control, carriers, syndrome, healthy controls, nasal epithelium, ARDS patients, circulating, differential gene expression analysis, let-7e-5p, log2FC, miR-146, miR-146a-5p, mRNA transcripts, neutrophil recruitment, OR52N2, total RNA, carrier, transcript, EVs, Vesicle, controls, Cell, bind, Result, resulting, analyzed, significantly, investigated, evaluated, inhibited, adjusted, activated, increase, alveolar cell, regulated, upregulated, downregulated, cell-to-cell communication, COVID-19 ARDS patient, differentially expressed miRNA, mechanically ventilated patient, mRNA transcript, prospectively studied, secrete, symptomatic patient, the healthy, with COVID-19, 【제목키워드】 miRNA, Corona,