Abstract
Purpose :
Zika virus (ZIKV) is a reemerging human pathogen that causes congenital abnormalities including microcephaly and eye disease. The cellular/molecular basis of ZIKV and host interactions inducing ocular and neuronal pathogenesis are unclear. We hypothesized that ZIKV effect on Hippo Pathway transcriptional activators contributes to ZIKV-mediated retinal and brain pathology. Hippo Pathway controls organ size through progenitor cell proliferation and differentiation.
Methods :
Both in vitro (cultured retinal and brain cells) and in vivo (Ifnar1-/- knockout mice) models of ZIKV infection were used to investigate the role of Hippo signaling. Transcriptomics and proteomics analyses of ZIKV infected fetal retinal pigment epithelial (fRPE) cells were performed to identify key signaling pathways altered due to ZIKV. The expression of genes/pathways at the protein levels were checked by western blotting and immunohistochemistry in mouse retina or brain. Pharmacological inhibition, overexpression, and siRNA mediated gene knockdown approaches were used to decipher the role of specific genes.
Results :
Our results indicated that the Hippo/Salvador-Warts-Hippo (SWH) signaling pathway is dysregulated following ZIKV infection. We observed that in human fRPE cells, there is an early induction of transcriptional co-activator, YAP, which is later degraded with a corresponding activation of the TBK1-IRF3 Type I interferon pathway. YAP/TAZ silencing results in reduced ZIKV replication, indicating a direct role of the Hippo pathway in regulating ZIKV infection. Using an in vivo Ifnar1-/- knockout mouse model, ZIKV infection was found to reduce YAP/TAZ protein levels while increasing pYAP Ser127 in the retina and brain. Hippo pathway is activated in major cellular components of the blood-brain barrier (BBB), including endothelial cells and astrocytes. In addition, our result suggests the AMPK signaling pathway’s role in regulating YAP/TAZ in ZIKV-infected RPE cells.
Conclusions :
Our data demonstrate that ZIKV infection might initiate crosstalk among AMPK-Hippo-TBK1 pathways, which could regulate antiviral and energy stress responses during oculo-neuronal inflammation.
This is a 2020 ARVO Annual Meeting abstract.