Fig. 4

Protein‒protein interaction (PPI) network analysis and hub genes identification. A PPI network for common DEGs that are shared by SARS-CoV-2 infection and cardiovascular diseases. Red nodes represent up-regulated DEGs, and blue nodes represent down-regulated DEGs. The size of the node responds to its degree in the network. The thickness of the edges is related to the strength of the interaction. B A key cluster with 15 genes was further chosen by MCODE plugin in Cytoscape. C The 11 hub genes identified according to four algorithms (MCC, MNC, degree, and EPC) of CytoHubba plugin in Cytoscape (see also Table 1). D The gene network and functional analysis of hub genes were generated using GeneMANIA. The inner circle stands for hub genes, and the outer circle refers to the corresponding reciprocal genes. Colors of nodes represent gene function annotations, which refer to GO terms enriched among the genes in the network displayed by GeneMANIA. Colors of edges represent interaction based on co-expression, physical interactions, co-localization, shared protein domain, or predicted interaction