Novel genes associated with a placental phenotype in knockout mice also respond to cellular stressors in primary human trophoblasts.

INTRODUCTION: Placental insufficiency is a leading cause of intrauterine growth restriction, contributing to perinatal morbidity and mortality. The molecular regulation of placental development and what causes placental insufficiency is poorly understood. Recently, a panel of genes were found to cause significant placental dysmorphologies in mice with severely growth restricted off-spring. We aimed to assess whether these genes were also implicated in human intrauterine growth restriction.

METHODS: We explored the expression of nine genes in primary cytotrophoblast cells in hypoxic (n = 6) and glucose starvation (n = 5) conditions in vitro. We also explored whether the genes were dysregulated in intrauterine growth restricted human placental samples (n = 11), with (n = 20) or without preeclampsia compared to gestationally matched controls (<34 weeks gestation) (n = 17).

RESULTS: Hypoxic stress significantly upregulated the expressions of BRD2 (p = 0.0313), SMG9 (p = 0.0313) genes. In contrast, glucose starvation significantly suppressed Kif1bp (p = 0.0089) in primary cytotrophoblasts. The FRYL, NEK9, CHTOP, PSPH, ATP11A, HM13 genes did not change under hypoxia or glucose starvation conditions. The expression of these genes was not altered in placenta from patients with intrauterine growth restriction, compared to gestationally matched controls.

DISCUSSION: We demonstrate that some of the genes that cause a placental phenotype in mice, respond to hypoxic and glucose mediated stress in human cytotrophoblast isolations. Despite this, they are unchanged in placenta from patients with intrauterine growth restriction. Therefore, dysregulation of these genes is less likely to contribute to preterm intrauterine growth restriction in humans.