Human cytomegalovirus (HCMV) is an opportunistic pathogen that has been implicated in the pathogenesis of
atherosclerosis.
Endothelin-1 (ET-1), a potent vasoconstrictive
peptide, is overexpressed and strongly associated with many vasculopathies. The main objective of this study was to investigate whether HCMV could affect ET-1 production. As such, both endothelial and smooth muscle cells, two primary cell types involved in the pathogenesis of
atherosclerosis, were infected with HCMV in vitro and ET-1
mRNA and
proteins were assessed by quantitative PCR assay, immunofluorescence staining and ELISA. HCMV
infection significantly decreased ET-1
mRNA and secreted bioactive ET-1 levels from both cell types and promoted accumulation of the ET-1 precursor
protein in infected endothelial cells. This was associated with inhibition of expression of the
endothelin converting enzyme-1 (ECE-1), which cleaves the ET-1 precursor
protein to mature ET-1.
Ganciclovir treatment did not prevent the virus suppressive effects on ET-1 expression. Consistent with this observation we identified that the IE2-p86
protein predominantly modulated ET-1 expression. Whether the pronounced effects of HCMV in reducing ET-1 expression in vitro may lead to consequences for regulation of the vascular tone in vivo remains to be proven.