[316-POS]: Cytomegalovirus dysregulation of HDAC6 function in cytotrophoblast invasion

Objectives Human cytomegalovirus (HCMV) infection of the placenta is associated with significant pathological consequences, including pregnancy loss, intrauterine growth restriction, preeclampsia and preterm labor. It is thought that some of these pathological anomalies are attributed to the inability of extravillous cytotrophoblasts (EVT) to adequately invade the maternal uterine wall during first trimester pregnancy resulting in impaired remodeling of maternal spiral arteries. Our earlier studies show that HCMV inhibits cytotrophoblast invasion, although the mechanism(s) involved are not fully understood. We hypothesize that HCMV inhibits activity of histone deacetylase 6 (HDAC6) that is involved in the balanced control of deacetylation/acetylation of alpha-tubulin and cortactin that is essential for invadosome formation and function. The purpose of this study is to determine whether HCMV inhibits invasion of EVT through dysregulation of HDAC6-dependent invadosome formation and function. Methods An organotypic, 3-dimensional (3-D) model system using primary first trimester trophoblast progenitor cells (TBPCs) or the SGHPL-4 cell line was used to induce differentiation of cytotrophoblasts into an invasive phenotype. Invasive cytotrophoblasts were plated on fluorescein-labeled gelatin and analyzed for invadosome formation and function by confocal microscopy. Cells were infected with HCMV or treated with HDAC6-specific inhibitors to determine the ability of both to abrogate EVT invasion and to increase levels of acetylated alpha-tubulin, a cytoplasmic substrate of HDAC6, the latter of which has been shown, in cancer cells, to be required for invadosome formation and function. Results Cytotrophoblasts cultured in 3-D form actin-rich invasive protrusions that degrade extracellular matrix. HDAC6-specific inhibition and HCMV infection inhibit cytotrophoblast invasion and increase levels of acetylated alpha-tubulin. Conclusions These data suggest that HCMV impairs trophoblast invadosome formation and function through dysregulation of HDAC6. Elucidating the mechanism(s) by which HCMV impairs placentation may be key to understanding and inhibiting fetal and maternal pathologies, such as preeclampsia. Disclosures K.F. Swan: None. M. Ferris: None. G. Pridjian: None. D.E. Sullivan: None. C.A. Morris: None.