Comparison of the myometrial transcriptome from singleton and twin pregnancies by RNA-Seq

Abstract

Preterm birth is recognized as the primary cause of infant mortality worldwide. Twin pregnancies are significantly more at risk of preterm birth than singleton pregnancies. A greater understanding of why this is and better modes of treatment and prevention are needed. Key to this is determining the differing pathophysiological mechanisms of preterm birth in twins, including the role of the myometrium and premature uterine contraction.We performed RNA sequencing (RNA-Seq) of human myometrium from singleton and twin pregnancies at term (> 37 +0 weeks) and preterm (< 37 +0 weeks), collected during prelabour Caesarean Section. RNA-Seq libraries were prepared from polyA-selected RNA and sequenced on the Illumina HiSeq 4000 platform. Differentially expressed genes (DEGs), GO (Gene Ontology) and KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway enrichment were conducted using R software. Significance was determined with a false discovery rate-adjusted P value of <0.05. Only 3 DEGs were identified between gestational age-matched singleton and twin myometrium and only 1 DEG identified between singleton term and twin preterm tissues. Comparison of singleton preterm myometrium with twin term myometrium however, revealed 75 down-regulated and 24 up-regulated genes in twin myometrium. This included genes associated with inflammation and immune response, T cell maturation and differentiation and steroid biosynthesis. GO and KEGG enrichment analyses for biologically relevant processes and functions also revealed several terms related to inflammation and immune response, as well as cytokine-cytokine receptor interaction and chemokine receptor signalling. Data indicate that little or no differences exist in the transcriptome of singleton and twin myometrium when matched for gestational age. The significant up-and down-regulation of genes identified between preterm singleton and twin myometrium at term may point to transcriptome changes associated with the chronic levels of uterine stretch in twin pregnancy or genes associated with the myometrium transitioning to labour onset.

MYB and ELF3 differentially modulate labor-inducing gene expression in myometrial cells

“…The difference in contractile ability between the functionally dormant cells at early gestation and those at full term (� 37 weeks in humans) is reflected through distinct, context-specific SMC transcriptomes. RNA-seq profiles generated from human myometrial cells indicate that these disparate gene expression patterns are determined by such conditions as: whether SMCs are isolated from a non-pregnant or pregnant individual [1]; labor status at term, or whether term-isolated SMCs were engaged in induced labor or active, spontaneous labor at the time of isolation [1,2]; the time point of labor, or whether or not SMCs are obtained at term or in advance of term [3][4][5]; and, in some cases, the relative localization within the myometrium or sub-population of the isolated SMCs [3,6]. In rodent models of labor, where SMCs can be collected from a wider range of gestational time points than their human counterparts, distinct stage-specific gene expression profiles are also observed.…”

Identification and validation of suitable reference genes for quantitative real-time PCR gene expression analysis in pregnant human myometrium

“…OXTR expression was shown to be is significantly different between singleton and twin myometrium depending to the RG set used. In a recent study using RNA Sequencing [ 32 ] which aimed to identify differences in gene expression between singleton and twin myometrium, no difference in the expression of OXTR was found. Hence, one would predict that the data normalised to CYC1 and YWHAZ rather than 18s and B2M in this study is reliable.…”

Evaluating aminophylline and progesterone combination treatment to modulate contractility and labor‐related proteins in pregnant human myometrial tissues

“…Myometrium biopsies from preterm pregnancies may have produced findings deemed more relevant to evaluating Ami and P4 efficacy for PTL prevention. Preterm and term non-laboring women comparisons have previously indicated that their myometrial transcriptomes are not notably different, 64,65 although may be distinct at gene ontology analysis 66 ; how this translates to differences in physiological output is undetermined. We were restricted to using biopsies from term caesarean sections because they were more frequent than preterm, which made achieving necessary biological replicates for each experiment more attainable.…”