Compared to the control siRNA-treated RA-FLSs (NC group) and as shown by KEGG enrichment analysis, differentially enriched proteins (DEPs) in si-HAPLN1-treated RA-FLSs were enriched in pathways including Staphylococcus aureus infection, systemic lupus erythematous (SLE), cardiomyopathy, COVID-19, and ribosome (Figure 7C). Here, HAPLN1 is linked to COVID-19.