[Transcriptome analysis in fetal lungs of SRC1/SRC2 double-knockout mice].

Steroid receptor coactivators (SRCs) significantly increase the transcriptional activity of various steroid hormone receptors, and play an important regulatory role in a variety of physiological functions such as food intake, sleep, stress response and reproduction. Previous studies have found that pregnant mice carrying fetuses with SRC1/2 double-knockout (dKO) manifested delayed labor, partly due to the hypoplasia of fetal lungs and the decreased secretion of pulmonary surfactant protein-A (SP-A) and platelet activating factor (PAF). However, there is still a lack of systematic analysis of the changes in gene expression at the whole transcriptome level in the fetal lungs of SRC1/2 dKO mice. In this study, the SRC1KO, SRC2KO, SRC1/2 dKO and wild-type (WT) mouse fetal lung samples were collected at 18.5 days post coitus. The Illumina platform was employed for transcriptome mRNA sequencing, and then the differentially expressed genes (DEGs) were annotated and analyzed by GO and KEGG analysis. The results showed that the proportion of quality score of the sequencing data above Q30 in all samples was more than 92% and passed the quality control. Compared with WT fetal lungs, SRC1KO and SRC2KO fetal lungs had 61 and 32 DEGs, respectively; SRC1/2 dKO fetal lungs had 480, 11 and 901 DEGs compared with WT, SRC1KO and SRC2KO fetal lungs, respectively. Among these genes, Aspg, Crispld2, Eln, Ntsr2, Slc10a6 and Vgll3 were the unique DEGs of SRC1/2 dKO fetal lungs compared with other genotype mice. Real-time PCR and Western blotting verified the reliability of transcriptome sequencing results. The GO analysis of the DEGs between SRC1/2 dKO and WT mouse fetal lungs showed that the DEGs were significantly enriched in the extracellular space, extracellular region, and extracellular matrix in terms of cellular component. In the biological process, they were significantly enriched in the term of development of multiple organs. KEGG pathway analysis showed that the DEGs were mainly enriched in signaling pathways such as the complement system, extracellular matrix-receptor interactions, and protein digestion and absorption. In summary, this study comprehensively revealed the changes of gene expression in the fetal lungs of SRC1/2 dKO mice at the transcriptome level, which provides a new theoretical basis for the study of the developmental regulatory mechanism of the fetal lung during pregnancy, and the fetus-derived signals that affect the initiation of labor.

Decrease in SHP-1 enhances myometrium remodeling via FAK activation leading to labor.

Preterm birth is one of the most common complications during human pregnancy and is associated with a dramatic switch within the uterus from quiescence to contractility. However, the mechanisms underlying uterine remodeling are largely unknown. Protein kinases and phosphatases play critical roles in regulating the phosphorylation of proteins involved in the smooth muscle cell functions. In the present study, we found that Src-homology phosphatase type-1 (SHP-1, PTPN6) was significantly decreased in human myometrium in labor compared with that not in labor. Timed-pregnant mice injected intraperitoneally with the specific SHP-1 inhibitor protein tyrosine phosphatase inhibitor I (PTPI-1) manifested significantly preterm labor, with enriched plasmalemmal dense plaques between myometrial cells and increased phosphorylation at Tyr397 and Tyr576/577 sites of focal adhesion kinase (FAK) in myometrial cells, which remained to the time of labor, whereas the phosphorylation levels of ERK1/2 and phosphatidylinositol 3 kinase (PI3K) showed a rapid increase upon PTPI-1 injection but fell back to normal at the time of labor. The Tyr576/577 in FAK played an important role in the interaction between FAK and SHP-1. Knockdown of SHP-1 dramatically increased the spontaneous contraction of human uterine smooth muscle cells (HUSMCs), which was reversed by coinfection of a FAK-knockdown lentivirus. PGF2α downregulated SHP-1 via PLCß-PKC-NF-κB or PI3K-NF-κB pathways, suggesting the regenerative downregulation of SHP-1 enhances the uterine remodeling and plasticity by activating FAK and subsequent focal adhesion pathway, which eventually facilitates myometrium contraction and leads to labor. The study sheds new light on understanding of mechanisms that underlie the initiation of labor, and interventions for modulation of SHP-1 may provide a potential strategy for preventing preterm birth.

H3K4me3-Mediated Upregulation of LncRNA-HEIPP in Preeclampsia Placenta Affects Invasion of Trophoblast Cells.

Preeclampsia (PE) is a pregnancy-related disease defined as onset of hypertension and proteinuria after the 20th week of pregnancy, which causes most maternal and perinatal morbidity and mortality. Although placental dysfunction is considered as the main cause of PE, the exact pathogenesis of PE is not yet fully understood. Long non-coding RNAs (lncRNAs) are implicated in a broad range of physiological and pathological processes, including the occurrence of PE. In this study, we investigated the expression and functions of HIF-1α pathway-related lncRNA-HEIPP (high expression in PE placenta) in the pathogenesis of PE. The expression of lncRNA-HEIPP in the placenta from women who underwent PE was screened by lncRNA microarray and then verified using real-time polymerase chain reaction. Then, the methylation profile of the lncRNA-HEIPP promoter and the enrichment of H3K4me3 binding were assessed by bisulfite pyrosequencing and chromatin immunoprecipitation (ChIP)-quantitative polymerase chain reaction (qPCR) assay, respectively. It was found that the level of lncRNA-HEIPP in the PE placenta was significantly higher than that in normal placenta and was increased in HTR-8/SVneo human trophoblast cells upon hypoxia treatment. Moreover, we reported that H3K4me3 manifested significantly higher promoter occupancy on lncRNA-HEIPP promoter in HTR-8/SVneo cells upon hypoxia treatment and found that the downregulation of lncRNA-HEIPP promoted trophoblast invasion. Our findings suggested that the hypoxia-induced expression of lncRNA-HEIPP mediated by H3K4me3 modification in trophoblast may contribute to the pathogenesis of PE.

The detrimental effects of glucocorticoids exposure during pregnancy on offspring's cardiac functions mediated by hypermethylation of bone morphogenetic protein-4.

The intra-uterine and external environmental factors not only affect the early development of fetuses, their interaction with genesis will also substantially program the physiological functions of offspring throughout life. Synthetic glucocorticoid (GC) is widely used for the management of women at risk of preterm birth or undergone autoimmune diseases. However, excess GC might cause a number of chronic diseases in later life. In the present study, we set up a programming rat model by daily injection of dexamethasone (DEX) since 14.5 dpc until labor, and found that the cardiac functions were significantly compromised in the male offspring compared with that exposed to NS, especially after ischemia/reperfusion (I/R), due to the increased infarction and apoptosis of myocardium. Using MeDIP sequencing, we identified four genes involved in the cardiac muscle cell differentiation and development pathway exhibited increased methylation in their promoter regions, among which, bone morphogenetic protein-4 (BMP4) expression is coordinately decreased in myocardium from male mice prenatally exposed to DEX. The programming effect of DEX on cardiomyocytes apoptosis was found to be dependent on mitochondria dysfunction, whereas the breakdown of mitochondrial membrane potential (ΔΨm) and the decrease of ATP production from mitochondria caused by prenatal DEX exposure both can be restored by BMP4 predisposing on neonatal cardiomyocytes 24 h prior to I/R. Inversely consistent with ΔΨm and ATP production, the release of reactive oxygen species was dramatically elevated in cardiomyocytes, which was significantly inhibited in the presence of BMP4 prior to I/R. These findings suggested that the excess GC exposure during pregnancy increases the susceptibility of male offspring's heart to "second strike", due to the decrease of BMP4 expression caused by the hypermethylation on Bmp4 promoter and the absence of BMP4 protective effect in cardiomyocytes, making the addition of BMP4 a promising treatment for the congenital heart disease under such circumstances.