Biomedical subjects

C-R Roh

Publications and source records attributed to C-R Roh.

3 recordsLinked to original sources

PubMed2006

Hypoxia regulates the expression of PHLDA2 in primary term human trophoblasts.

Hypoxia influences gene expression in placental trophoblasts. We sought to examine the effect of hypoxia on trophoblast expression of human PHLDA2 (also termed IPL, TSSC3 or BWR-1C), a product of an imprinted gene on human chromosome 11p15.5 whose murine ortholog plays a pivotal role in placental development. We initially confirmed that PHLDA2 was expressed in term placental villi, primarily in the trophoblast layer. Using quantitative PCR we found that the expression of PHLDA2 gradually declined during differentiation of primary term human trophoblasts. A similar expression pattern was seen for p57(Kip2) and IGF-II, both products of imprinted genes on chromosome 11p15.5. Exposure of trophoblasts to hypoxia in vitro (O(2)<or=2%) markedly reduced the expression of PHLDA2 mRNA and protein. This effect was not consistent among other chromosome 11p15.5 genes products, as the expression of p57(Kip2) decreased, but that of IGF-II increased in hypoxic trophoblasts. PHLDA2 expression in trophoblasts exposed to TGFbeta1, -beta2 or -beta3 was unchanged. We conclude that hypoxia down-regulates the expression of PHLDA2 in human term placental trophoblasts. As murine PHLDA2 limits placental growth, our results suggest that down-regulation of PHLDA2 attenuates the impact of hypoxia on placental growth.

Cells, Cultured↗

PubMed2005

Microarray-based identification of differentially expressed genes in hypoxic term human trophoblasts and in placental villi of pregnancies with growth restricted fetuses.

Hypoxia adversely influences the function of the human placenta. We sought to identify a set of hypoxia-regulated transcripts in both term human trophoblasts in vitro and in villous trophoblasts in vivo. Using high-density oligonucleotide microarrays we initially examined differences in gene expression between trophoblast cultured in standard conditions (20% oxygen) vs. hypoxic conditions (< or =1% oxygen), as well as in placental tissues from pregnancies complicated by intrauterine growth restriction vs. matched controls. We used a novel computation method to compile data from the two approaches and identify transcripts that exhibited a marked expression change. Using quantitative PCR we confirmed an up-regulation of transcripts for vascular endothelial growth factor, connective tissue growth factor, follistatin-related protein, N-Myc down-regulated gene 1 and adipophilin in hypoxic term trophoblasts. In contrast, the expression of human placental lactogen and Beckwith-Wiedemann region 1 C was reduced in hypoxic trophoblast. Using in situ hybridization we validated the expression of each transcript in cultured term villous trophoblasts, and determined transcript expression in placental samples derived from four sets of dichorionic twins complicated by growth restriction of one twin. The identification of hypoxic trophoblast signature transcripts may implicate new mediators in pathways underlying trophoblast hypoxic injury and adaptation.

Base Sequence↗

PubMed2005

The correlation between sampling site and gene expression in the term human placenta.

Using oligonucleotide microarrays we recently identified a set of transcripts that were up-regulated in hypoxic human trophoblasts. To test the hypothesis that expression of hypoxia-related placental transcripts depends on sampling site we analyzed nine different sites from term human placentas (n=6), obtained after uncomplicated pregnancies. These sites spanned the placental center to the lateral border and the basal to the chorionic plate. Relative gene expression at each site, determined using quantitative PCR, was correlated with villous histology. The expression of vascular endothelial growth factor (VEGF) and connective tissue growth factor (CTGF), the cytoskeleton proteins lamininA3 and alpha-tubulin, and the signal transduction protein Rad was enhanced in the subchorionic lateral border compared to medial basal site (1.6-2.9 fold, p<0.05). In contrast, the expression of NDRG1, adipophilin and human placental lactogen was unchanged. Enhanced villous maturation, syncytial knots and fibrin deposits were more frequent in the subchorionic placental lateral border, and correlated with up-regulation of hypoxia-related transcripts (p<0.05). The association between sample site and expression level was not observed in placentas with marginal cord insertion. The expression of hypoxia-related genes in the term human placenta is dependent on sampling site within the placental disk, likely reflecting local differences in villous perfusion.

Base Sequence↗