Identification of HTRA4 as a trasncritpional target of P63 in trophoblast

The placenta plays a crucial role in pregnancy success. deltaNp63alpha (p63), a transcription factor from the TP53 family, is highly expressed in villous cytotrophoblasts (CTBs), the epithelial stem cells of the human placenta, and has been shown to be involved in CTB maintenance and differentiation. In this study, we set out to identify mechanism(s) of action of p63, by identifying its downstream targets. We evaluate gene expression changes following overexpression and knockdown of p63 in the JEG3 choriocarcinoma cell line, using microarray-based RNA profiling. We identify High temperature requirement A4 (HTRA4), a placenta-specific serine protease involved in trophoblast differentiation and altered in preeclampsia, as a gene reciprocally regulated by p63, and characterize its expression in primary human placental tissues by RNAseq (PMID 34540826; GSE173372) and in situ hybridization. Forced overexpression of deltaNp63alpha in JEG-3 was obtained by pCMV lentiviral vector infection (empty vector used as control). ) The pLKO.1-based non-targeting scramble and p63-specific short hairpin (shRNA) lentiviral plasmids were used for gene knock-down. Vectors were previously described in Li et al Am J Pathol. 2014 PMID: 25307348. Mary E. Donohoe