Pleiotropy and Redundancy of STAT Proteins in Early Pregnancy
ABSTRACT Signal transducers and activators of transcription (STATs) are a group of proteins involved in signal transduction from numerous bioactive substances. Hormones and cytokines such as leukaemia inhibitory factor, interferon-tau and prolactin, which play key roles during early pregnancy, activate the Janus kinase (JAK)/STAT signalling pathway. The STATs are thus involved in the regulation of implantation, establishing uterine receptivity and regulation of the maternal immune response. It seems that STATs can orchestrate signals from hormones and cytokines in different cell types and may therefore generate numerous biological effects, despite the relatively small number of receptors activating the JAK/STAT pathway. This review summarizes the participation of STATs in the main processes of early pregnancy, especially regarding their pleiotropy and redundancy.
SourceAvailable from: Wittaya Chaiwangyen[Show abstract] [Hide abstract]
ABSTRACT: Invasiveness of trophoblast and choriocarcinoma cells is in part mediated via leukemia inhibitory factor- (LIF-) induced activation of signal transducer and activator of transcription 3 (STAT3). The regulation of STAT3 phosphorylation at its ser727 binding site, possible crosstalk with intracellular MAPK signaling, and their functional implications are the object of the present investigation. JEG-3 choriocarcinoma cells were cultured in presence/absence of LIF and the specific ERK1/2 inhibitor (U0126). Phosphorylation of signaling molecules (p-STAT3 (ser727 and tyr705) and p-ERK1/2 (thr 202/tyr 204)) was assessed per Western blot. Immunocytochemistry confirmed results, but also pinpointed the location of phosphorylated signaling molecules. STAT3 DNA-binding capacity was studied with a colorimetric ELISA-based assay. Cell viability and invasion capability were assessed by MTS and Matrigel assays. Our results demonstrate that LIF-induced phosphorylation of STAT3 (tyr705 and ser727) is significantly increased after blocking ERK1/2. STAT3 DNA-binding capacity and cell invasiveness are enhanced after LIF stimulation and ERK1/2 blockage. In contrast, proliferation is enhanced by LIF but reduced after ERK1/2 inhibition. The findings herein show that blocking ERK1/2 increases LIF-induced STAT3 phosphorylation and STAT3 DNA-binding capacity by an intranuclear crosstalk, which leads to enhanced invasiveness and reduced proliferation.The Scientific World Journal 10/2013; 2013:259845. DOI:10.1155/2013/259845 · 1.73 Impact Factor
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ABSTRACT: In pigs, implantation begins with the attachment of embryos to the endometrium. As the process is regulated by the expression of numerous genes, endometrial transcriptomic profiles have been extensively studied in early gravid pigs. However, the myometrium, a secretory tissue, should not be neglected, as it can also participate in the regulation of implantation in early pregnant pigs. To clarify this issue, the transcriptomic profile of the porcine myometrium during the peri-implantation period (i.e. on days 15 to 16 of pregnancy) was compared with the profile observed during luteolysis (i.e. on days 15 to 16 of the oestrous cycle) with an Agilent's Porcine (V2) Two-Colour Gene Expression Microarray 4 × 44 (Agilent, USA). Analysis of the microarray data revealed that of 526 unique, accurately annotated genes, the expression of 271 unique genes was upregulated, while the expression of 255 genes was downregulated in pregnant versus cyclic myometrium. The in-depth data analysis revealed differential expression of genes encoding for factors involved in immunomodulation, tissue growth and differentiation, and prostaglandin and steroid biosynthesis and action. Moreover, the comparison of the obtained data on the myometrial transcriptome with our previously published results on the endometrial transcriptome allowed us to determine substantial differences in the regulatory function of both tissues. The new insights into the function of the myometrium of early pregnant pigs obtained here are in agreement with our previous results that suggest that this tissue plays an important role in providing optimal conditions for developing embryos. Therefore, the importance of the myometrium as an active embryo signal-responsive tissue during early pregnancy cannot be underestimated.Functional and Integrative Genomics 09/2014; DOI:10.1007/s10142-014-0401-4 · 2.69 Impact Factor
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ABSTRACT: Pregnancy is personally special to every woman expecting a child, but is also interesting from the perspective of an immunologist. During a physiological pregnancy, the mother's immune system decides to tolerate and foster an incorporated, non-self, non-dangerous organism. Whether the maternal reaction stems from deciphering the foreigness or safeness of this new individual, it is the general consensus that there is a foeto-maternal, bidirectional "dialogue" occurring and that the "messages" that are "spoken" are relayed through signaling mediators, which are capable of transmitting a functional command to a target cell. Much information dedicated to this theme has been gleaned in the past decade; however, the complex nature of cytokine networks jeopardizes clarity. In this review, we touch upon a list of mediators that are vital for reproduction. These factors are divided according to their receptor family, because this elucidates the characteristic signal transducing pathway, which is expected to mediate their signal within the target cell. The target cells of interest are the trophoblast, upon which we focus for several reasons: 1. the trophoblast represent the foetal compartment while participating in foeto-maternal interplay (e.g. while invading the decidua, trophoblasts are in constant communication with uterine, maternal immunocytes, which check and contain this function), 2. trophoblasts are responsible for foetal well-being (e.g. nutrition, protection from the environment) and 3. dysfunctional trophoblast function results in several pregnancy complications (e.g. preeclampsia, intrauterine growth retardation, miscarriage, preterm delivery). We summarize what is described in the literature on how these mediators are distributed within the reproductive tract, which cells are expressing their respective receptors (especially which trophoblast subsets) and how they modify trophoblast function