Human cytomegalovirus infection modulates thrombospondins 1 and 2 in primary fetal astrocytes

Transmission of human cytomegalovirus (HCMV) to the fetus is the most common type of intrauterine infection; the mechanism of HCMV pathogenesis in the developing central nervous system remains unclear. Thrombospondins 1 and 2 (TSP1, TSP2) produced by immature astrocytes are critical for fetal synaptogenesis. To examine the effect of HCMV on fetal astrocytes, human fetal astrocytes were isolated and cultured with HCMV AD169. Cells were harvested at different time points. Protein and mRNA expressions of TSP1 and TSP2 were determined using RT-qPCR, western blotting analysis, and enzyme-linked immunosorbent assay. The results showed that HCMV infection induced time-dependent decreases in mRNA and protein expressions of both TSP1 and TSP2 in astrocytes. Flow cytometry was used to detect apoptosis of HCMV-infected astrocytes, and the result indicated that there was no linkage between cell apoptosis and the decrease in TSP1 and TSP2 expressions induced by HCMV infection. When ganciclovir treatment was performed on HCMV-infected astrocytes, results showed that ganciclovir treatment inhibited the reduction of TSP1 and TSP2 expression in astrocytes. In the further study, pEGFP-N3-IE1 was transfected into astrocytes to identify that it was not IE1 but active viral replication that was essential in the continuous decrease of TSP1 and TSP2 expressions in HCMV-infected astrocytes.