ABSTRACT
We previously reported that treatment with tricin (4’,5,7-trihydroxy-3’,5’-dimethoxyflavone) after human cytomegalovirus (HCMV) infection significantly suppressed both infectious virus production and HCMV replication in human embryonic lung fibroblast (HEL) cells. Moreover, we recently revealed that HCMV infection can increase the expression of CC-motif ligand 2 (CCL2/MCP-1) and CCR2, a specific receptor for CCL2, which can enhance HCMV infection and replication, in turn. In this study, we examined whether CCL2 and/or CCR2 are involved in the anti-HCMV effects of tricin in HEL cells. Exposure of fibroblasts to tricin inhibited infectious HCMV production, with concomitant decreases in CCL2 and CCR2 transcript levels and CCL2 protein levels in a dose-dependent manner. Propagermanium, an inhibitor of CCR2 function, has also been shown to inhibit infectious HCMV production with concomitant decreases in CCL2 protein levels. We further observed that tricin and propagermanium reduced mRNA expression of HCMV immediate early gene and DNA polymerase in a dose-dependent manner. These results suggest that tricin is a novel anti-inflammatory compound with potential anti-HCMV activity, and CCL2/CCR2 interactions are associated with HCMV replication.