Tea Ingredients Have Anti-coronavirus Disease 2019 (COVID-19) Targets Based on Bioinformatics Analyses and Pharmacological Effects on LPS-Stimulated Macrophages

Abstract

Coronavirus disease 2019 (COVID-19) is a contagious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that caused millions of deaths and lacks treatment. Although several studies have focused on the major component of green tea, epigallocatechin 3-gallate (EGCG), which is efficient in preventing COVID-19, systemic analyses of the anti-COVID-19 potential of green tea remain insufficient. Here, we co-analyzed the target genes of tea ingredients and COVID-19 signature genes and found that epigallocatechin 3-acetalbehyde was capable of reversing the major molecular processes of COVID-19 (MAPK and NF-κB activation). These findings were further supported by Western blotting (WB), immunofluorescence, and quantitative polymerase chain reaction (qPCR) in LPS-stimulated macrophages. Moreover, using molecular docking analysis, we identified three tea ingredients ((-)-catechin gallate, D-(+)-cellobiose, and EGCG) that may interact with the vital SARS-CoV-2 protein, 5R84, compared with the qualified 5R84 ligand WGS. Thus, our results indicated that tea ingredients have the potential to treat COVID-19 by suppressing the COVID-19 signature genes and interacting with the vital SARS-CoV-2 protein.

Keywords: COVID-19; key targets; macrophage; molecular docking; network pharmacology; tea ingredients.

Figure 1

The ingredients and target genes of tea. (A) The network of tea ingredients and target genes, the dot color represents the components, while green, red, and blue represents the tea, tea ingredients, and target genes, respectively. (B) The target genes bar plot of each tea ingredient. (C) The GO enrichment map of tea target genes organized enriched terms into a network with edges connecting overlapping genes and easier to identify hub module. (D) The KEGG enrichment bar plot of the top 30 enriched terms, the bar color represents the P-value of each term.

Figure 2

The gene signature of COVID-19. (A) The Venn plot of COVID-19 gene signature of DisGeNET and KEGG. (B) The shared COVID-19 gene signature GO terms of DisGeNET and KEGG. (C) The comparison GO enrichment network of DisGeNET and KEGG, the number of circles in the bottom left corner represents the gene number of each enriched term, the proportion of clusters in the pie chart is determined by the number of genes. (D) The PPI of shared genes of DisGeNET and KEGG COVID-19 gene signature, the dot color represents the connectivity of each gene, while from yellow to red represents from low to high. (E) The top 10 KEGG enriched terms of shared COVID-19 signature genes. (F) The genes and GO enriched terms network of shared COVID-19 signature genes, the red dots represent the GO enriched terms while blue dots are the related genes.

Figure 3

The anti-COVID-19 potential of tea. (A) The Venn plot of COVID-19 signature genes and tea target genes. (B) The shared GO enriched terms of COVID-19 signature genes and tea target genes. The comparison GO (C) and KEGG (D) enrichment network of COVID-19 signature genes and tea target genes, the bottom left circles stand for the gene number of each enriched term, the proportion of clusters in the pie chart indicates the number of genes. (E) The network of shared COVID-19 signatures genes and tea target genes along with the GO and KEGG enrichment terms.

Figure 4

The molecular docking analysis of tea ingredients with COVID-19 5R84 protein. (A) The binding-free energy and hydrogen bond numbers of tea ingredients with 5R84 protein with qualified 5R84 ligand WGS as a reference, the red dot horizontal line indicates the binding-free energy of WGS with 5R84. (B) The representative interaction of tea ingredients and WGS with 5R84, the yellow dot lines indicate the hydrogen bonds of the specific ligand with 5R84.

Figure 5

EGCG suppressed secretion of inflammatory factors, macrophage polarization, and MAPK/NF-κB signaling in vitro. (A) RAW 264.7 cells were incubated with EGCG (50 mM) for 24 h. Cell viability was determined by CCK8 assay (n = 5). (B–F) The mRNA levels of iNOS, TNF-α, Il-1β, IL-6, and Arg1 in the RAW 264.7 cells with LPS (100 ng/ml) and EGCG (50 nM) for 24 h were detected by q-PCR (n = 3). (G–I) The concentrations of IL-6, TNF-α, and IL-1β in RAW 264.7 cell supernatant after LPS and EGCG treatment for 24 h were determined by ELISA kits (n = 4). (J) The protein levels of ERK1/2, P-ERK1/2, JNK, P-JNK, P38, and p-p38 in the RAW 264.7 cells treated with LPS (100 ng/ml) and EGCG (50 nM) for 24 h were detected by Western blotting. (K) The expressions of p-p65 (red) and DAPI (blue) in RAW 264.7 cells were detected by using an immunofluorescence staining assay (scale bar: 50 μm). ^*P < 0.1, ^**P < 0.01, ^***P < 0.001, ****P < 0.0001.