H19 long noncoding RNA alters trophoblast cell migration and invasion by regulating TβR3 in placentae with fetal growth restriction

Abstract

Fetal growth restriction (FGR) is a well-recognized risk factor for perinatal mortality and morbidity, as well as neurodevelopmental impairment and adulthood onset disorders. Here we report that the H19 long noncoding RNA (lncRNA) is significantly decreased in placentae from pregnancies with FGR. Downregulation of H19 leads to reduced migration and invasion of extravillous trophoblast (EVT) cells in vitro. This is consistent with reduced trophoblast invasion that has been observed in FGR. Genome-scale transcriptome profiling of EVT cells reveals significantly decreased expression of the type III TGF-β receptor (TβR3) following H19 knockdown. Decreased TβR3 expression is also seen in FGR placentae. TβR3 repression decreases EVT cell migration and invasion, owing to impaired TGF-β signaling through a non-canonical TGF-β signaling pathway. Further, we identify TβR3 as a novel regulatory target of microRNA let-7. We propose that dysregulation of this newly identified H19/TβR3-mediated regulatory pathway may contribute to the molecular mechanism of FGR. Our findings are the first to show a lncRNA-based mechanism of FGR, holding promise for the development of novel predictive, diagnostic, and therapeutic modalities for FGR.

Mechanistic Insight into Long Noncoding RNAs and the Placenta

“…A partial loss of imprinting (LOI), together with biallelic expression of H19 , were detected in placentas from SGA and PE pregnancies [ 26 , 73 , 76 ]. Similarly, LOI of H19 and biallelic expression were also linked to foetal growth restriction (FGR) [ 33 ] while the maternally inherited single nucleotide polymorphism rs2071094 in H19 has also been shown to associate with increased birth weight [ 32 ]. This LOI may result in an increase in expression of H19 and mir-675 (a growth suppressor) resulting in SGA and FGR pregnancies.…”

H19/TET1 axis promotes TGF‐β signaling linked to endothelial‐to‐mesenchymal transition

“…iLet7 are chemically modified, single‐stranded nucleic acids that specifically bind to let‐7 and block its activity. The effect of H19 knockdown (ie, downregulation of TET1) was expected to be abrogated in the presence of iLet7, which acts to neutralize let‐7 released from H19 sequestration 7,48‐50,52 . Indeed, H19 knockdown resulted in decreased TET1 expression at both the mRNA (Figure 3B) and protein (Figure 3C) levels and the expression was restored to control levels in the presence of iLet7.…”

“…We have previously documented that H19 acts as a molecular sponge for microRNA let‐7 37 . Both human and mouse H19 contains multiple binding sites for let‐7; binding of H19 to let‐7 sequesters let‐7 and prevents it from inhibiting target gene expression (hence, H19 functions to reduce the bioavailability of let‐7) 7,37,48‐50 . Binding of let‐7 to complementary sequences in target mRNAs results in translational repression and/or mRNA degradation 51 .…”

The effects of placental long noncoding RNA H19 polymorphisms and promoter methylation on H19 expression in association with preeclampsia susceptibility

“…Although its expression is high in the placenta and embryo, it strongly declines after delivery in most adult tissues. Increased levels of H19 expression in embryonic tissues result in the regulation of embryonic growth and development and placental cytotrophoblast differentiation . The recent literature has reported the overexpression of lncRNA‐H19 in preeclamptic placentas compared to healthy controls .…”

“…Increased levels of H19 expression in embryonic tissues result in the regulation of embryonic growth and development and placental cytotrophoblast differentiation. 19,20 The recent literature has reported the overexpression of lncRNA-H19 in preeclamptic placentas compared to healthy controls. 21 It has been shown that H19 acts as a primary microRNA precursor, and H19 expression regulates specific mRNAs via post-transcription.…”