Molecular pathways of senescence regulate placental structure and function

High-throughput miRNA sequencing of the human placenta: expression throughout gestation

Aim: To understand miRNA changes across gestation in healthy human placentae. This is essential before miRNAs can be used as biomarkers or prognostic indicators during pregnancy. Materials & methods: Using next-generation sequencing, we characterize the normative human placenta miRNome in first (n = 113) and third trimester (n = 47). Results & conclusion: There are 801 miRNAs expressed in both first and third trimester, including 182 with similar expression across gestation (p ≥ 0.05, fold change ≤2) and 180 significantly different (false discovery rate <0.05, fold change >2). Of placenta-specific miRNA clusters, chromosome 14 miRNA cluster decreases across gestation and chromosome 19 miRNA cluster is overall highly expressed. Chromosome 13 clusters are upregulated in first trimester. This work provides a rich atlas of healthy pregnancies to direct functional studies investigating the epigenetic differences in first and third trimester placentae.

Long non-coding RNA SNHG29 regulates cell senescence via p53/p21 signaling in spontaneous preterm birth

INTRODUCTION

Spontaneous preterm birth affects>5-18% of pregnancies and causes infant morbidity and mortality. Long non-coding RNAs can regulate gene expression and have been associated with preterm birth. In this study, we investigated whether the long non-coding RNA SNHG29 was associated with spontaneous preterm birth.

METHODS

We collected the placentas from women who underwent preterm/full-term birth with/without labor. We determined the levels of expression of SNHG29 in the placental tissues using quantitative real-time polymerase chain reaction. We generated a senescence model by treating HTR8/SVneo cells with 200 μM H2O2 for 2 h. The degree of senescence induced in cells depleted of or overexpressing SNHG29 was determined by measuring senescence-associated gene expression and β-galactosidase activity.

RESULTS

SNHG29 was overexpressed in the placentas of women who delivered preterm with labor and in HTR8/SVneo cells treated with H2O2 (p < 0.05). The levels of mRNA of p53 and p21, protein levels of p53, phospho-p53, p21and phospho-p21, and β-galactosidase activity was decreased in HTR8/SVneo cells depleted of SNHG29, while the opposite trend was observed in HTR8/SVneo cells overexpressing SNHG29 (p < 0.05). We observed an increase in the expression of IL-8 and TNF-α in senescent HTR8/SVneo cells (p < 0.05).

DISCUSSION

SNHG29 was overexpressed in placentas from women who delivered preterm with labor compared to those in women who underwent preterm birth without labor and full-term birth with/without labor. High levels of SNHG29 enhanced senescence in vivo. The increase in pro-inflammatory cytokine expression and release by senescent cells may be pivotal to the pathophysiology of spontaneous preterm birth.