The human myometrium differentially expresses mTOR signalling components before and during pregnancy: Evidence for regulation by progesterone

• Published in: The Journal of steroid biochemistry and molecular biology 2014-01, Vol.139, p.166-172
• Main Authors: Foster, Helen A., Davies, Julie, Pink, Ryan C., Turkcigdem, Serife, Goumenou, Anastasia, Carter, David R., Saunders, Nigel J., Thomas, Peter, Karteris, Emmanouil
• Format: Article
• Language: English
• Subjects: Adaptor Proteins, Signal Transducing - genetics; Adaptor Proteins, Signal Transducing - metabolism; Carrier Proteins - metabolism; Cells, Cultured; Cytokines - physiology; Female; Gene Expression Regulation; Humans; Inflammation Mediators - physiology; Intracellular Signaling Peptides and Proteins; mTOR; Myometrium; Myometrium - metabolism; Oligonucleotide Array Sequence Analysis; Pregnancy; Preterm labour; Progesterone; Progesterone - physiology; Rapamycin-Insensitive Companion of mTOR Protein; Regulatory-Associated Protein of mTOR; Signal Transduction; TOR Serine-Threonine Kinases - genetics; TOR Serine-Threonine Kinases - metabolism; Transcriptome
• ISSN: 0960-0760; 1879-1220
• DOI: 10.1016/j.jsbmb.2013.02.017

► DEPTOR was in all pregnant states when compared to non-pregnant myometria. ► The human myometrial ULTR cell line express mTORC1 and mTORC2 components. ► Progesterone down-regulated mTOR, DEPTOR, Rictor and Raptor in myometrial cells. ► Microarray revealed down-regulation of mTOR-related signalling components in P4-treated samples. Emerging studies implicate the signalling of the mammalian target of rapamycin (mTOR) in a number of reproductive functions. To this date, there are no data regarding the expression of mTOR signalling components in the human myometrium during pregnancy. We hypothesized that mTOR-related genes might be differentially expressed in term or preterm labour as well as in labour or non-labour myometria during pregnancy. Using quantitative RT-PCR we demonstrate for first time that there is a significant downregulation of mTOR, DEPTOR, and Raptor in preterm labouring myometria when compared to non-pregnant tissues taken from the same area (lower segment). We used an immortalized myometrial cell line (ULTR) as an in vitro model to dissect further mTOR signalling. In ULTR cells DEPTOR and Rictor had a cytoplasmic distribution, whereas mTOR and Raptor were detected in the cytoplasm and the nucleus, indicative of mTORC1 shuttling. Treatment with inflammatory cytokines caused only minor changes in gene expression of these components, whereas progesterone caused significant down-regulation. We performed a non-biased gene expression analysis of ULTR cells using Nimblegen human gene expression microarray (n=3), and selected genes were validated by quantitative RT-PCR in progesterone treated myometrial cells. Progesterone significantly down-regulated key components of the mTOR pathway. We conclude that the human myometrium differentially expresses mTOR signalling components and they can be regulated by progesterone. This article is part of a Special Issue entitled ‘Pregnancy and Steroids’.