Fig. 1

The landscape characteristics of cell-free circulating RNAs (cfRNAs) in the plasma of COVID-19 patients; no SARS-CoV-2 RNA was detected in COVID-19 patient plasma. a Schematic diagram showing the sample preparation procedure in this study. cfRNAs were collected from 3 healthy donors and 5 COVID-19 patients. b The computational pipeline to detect human RNAs and SARS-CoV-2 RNAs. c Bar plot showing the mapping rate and number of mapped reads against the SARS-CoV-2 genome (n = 32). d Bar plot and pie plot showing the composition of detected genes in all samples. Data are shown as the mean ± SD (n = 32). e Heatmap showing fold changes (relative to healthy donors) of 2,583 upregulated cfRNA genes and 192 downregulated cfRNA genes in COVID-19 patients. Blue and red represent log₂-transformed fold changes < 0 and > 0, respectively. f GO and KEGG enrichment analyses of 2,583 upregulated cfRNA genes in COVID-19 patients (left). Expression levels (TPMs) of IL-6R and representative interferon-stimulated genes (ISGs) are shown on the right. g Volcano plot showing up- and downregulated microRNA (miRNA) and long noncoding RNA (lncRNA) genes in COVID-19 patients relative to healthy donors (left). Relative expression of miR-451a, LOC105371414, LOC105374981 and LOC107987081 is shown on the right. h Base-pairing interaction between miR-451a and IL-6R (top) and the three upregulated lncRNAs (bottom). miR-451a target sites (seed sequences) are highlighted in red. i A proposed model for the regulatory network of miR-451a, IL-6R and lncRNAs in healthy donors and COVID-19 patients. Asterisks indicate statistically significant differences: **P < 0.01; ***P < 0.001