TET2-mediated DNA hydroxymethylation of TGFB1 is related to selective intrauterine growth restriction in monochorionic twin pregnancies

INTRODUCTION

Selective intrauterine growth restriction (sIUGR), which specifically occurs in monochorionic (MC) twins, usually has a poor prognosis and the underlying mechanisms are not well understood. It is an ideal model for exploring epigenetic-modified mechanisms for fetal development in MCDA twins due to eliminating the interference of different heritable backgrounds and intrauterine environments among individuals.

METHODS

The levels of ten-eleven translocation 2 (TET2) and its upstream and downstream targets miR-29b-3p and transforming growth factor beta 1 (TGFB1) were determined using RT‒qPCR, western blotting, and immunohistochemistry. Using TET2 overexpression and knockdown methods, we investigated the role of TET2 in trophoblast functions. The regulatory relationships among TET2, miR-29b-3p, and TGFB1 were explored by cell migration assay, invasion assay, apoptotic ratio assays, Western blot, hMeDIP-qPCR and dual-luciferase assay.

RESULTS

A consistent upregulation of TET2 and TGFB1 was observed in the smaller placental shares compared to the larger placental shares in sIUGR. Gain-of-function studies of TET2 in trophoblasts showed decreased cell invasion and increased apoptosis, whereas loss-of-function studies of TET2 rescued this effect. Mechanistic studies revealed that miR-29b-3p and TGFB1 were the upstream factor and downstream target of TET2, respectively. Furthermore, miR-29b-3p/TET2/TGFB1-smad was identified as a unique axis that regulates trophoblast invasion, migration, and apoptosis in a DNA hydroxymethylation-dependent manner.

DISCUSSION

We elucidated the functional roles of TET2 and DNA hydroxymethylation in trophoblasts and identified a novel DNA regulatory mechanism, providing a basis for further exploration of DNA epigenetic regulatory patterns in sIUGR.

N-hydroxy-N'-(4-butyl-2-methylphenyl)-formamidine attenuates oxygen-glucose deprivation and reoxygenation-induced cerebral ischemia-reperfusion injury via regulation of microRNAs

Cerebral ischemia-reperfusion injury is a common complication that occurs during stroke treatment. Increasingly, microRNAs have been found to participate in the modulation of neuron function; however, the role of microRNAs in cerebral ischemia-reperfusion injury remains unclear. We developed a mechanism of cerebral ischemia-reperfusion injury using a cellular model of oxygen-glucose deprivation and reoxygenation-induced injury in human neuroblastoma SH-SY5Y cells. We found that treatment of oxygen-glucose deprivation and reoxygenation promoted the apoptosis of SH-SY5Y cells. Analysis of microRNAs sequencing revealed that the expression of microRNA-27a-5p was induced, and microRNA-29b-3p expression was inhibited in neuroblastoma cells exposed to oxygen-glucose deprivation and reoxygenation. Either inhibition of microRNA-27a-5p or overexpression of microRNA-29b-3p mitigated oxygen-glucose deprivation and reoxygenation-induced cellular apoptosis. Bach1 was authenticated as a target gene of microRNA-27a-5p. Also, microRNA-27a-5p mediated the expression of Bach 1 along with its downstream signaling. N-hydroxy-N'-(4-butyl-2-methylphenyl)-formamidine protected against oxygen-glucose deprivation and reoxygenation-induced apoptosis while decreasing miR-27a-5p expression and increasing microRNA-29b-3p expression. These results suggested that microRNA-27a-5p and microRNA-29b-3p may contribute to oxygen-glucose deprivation and reoxygenation-induced cellular injury. At the same time, N-hydroxy-N'-(4-butyl-2-methylphenyl)-formamidine protects SH-SY5Y cells against oxygen-glucose deprivation and reoxygenation-induced injury partly through the inhibition of microRNA-27-a-5p and promotion of the Bach1/HO-1 signaling pathway.