Expression of leukaemia inhibitory factor (LIF) during the window of implantation in copper T380A intrauterine device users

Effects of Excess Copper Ions on Decidualization of Human Endometrial Stromal Cells

The aim of this study was to investigate the effects of copper ions on decidualization of human endometrial stromal cells (HESCs) cultured in vitro. Firstly, non-toxic concentrations of copper D-gluconate were screened in HESCs based on cell activity. Then, the effects of non-toxic concentrations of copper ions (0~250 μM) were examined on decidualization of human endometrial stromal cells. Our data demonstrated that the mRNA expressions of insulin-like growth factor binding protein (IGFBP-1), prolactin (PRL), Mn-SOD, and FOXO1were down-regulated during decidualization following the treatments with 100 or 250 μM copper ions. Meanwhile, the amount of malonaldehyde (MDA) in the supernatant of HESCs was increased. These results showed that in vitro decidualization of HESCs was impaired by copper treatment.

Association between leukaemia inhibitory factor gene polymorphism and pregnancy outcomes after assisted reproduction techniques

Certain gene polymorphisms are associated with implantation failure and pregnancy loss. Studies of leukaemia inhibitory factor (LIF) gene polymorphisms are scarce. The LIF single nucleotide polymorphism (SNP) thymine (T)/guanine (G) (rs929271) was studied in women to determine whether an association existed with pregnancy outcomes after intracytoplasmic sperm injection (ICSI); 411 women who underwent ICSI were recruited. DNA was extracted from the peripheral blood, and the LIF gene SNP T/G (rs929271) was genotyped using real-time polymerase chain reaction. Participants were divided into three groups according to their LIF genotype: T/T (n = 168), T/G (n = 202) and G/G (n = 41). All IVF and ICSI procedures were carried out under the same clinical and laboratory conditions. The ICSI cumulative results (from fresh plus frozen cycles) of each genotype group were analysed. The G/G genotype in women was associated with a higher implantation rate (T/T: 15.9%, T/G: 16.2%, G/G: 27.0%; P < 0.05), ongoing pregnancy rate/patient (T/T: 31.5%, T/G: 36.1%, G/G: 53.7%; P < 0.05) and ongoing pregnancy rate/transfer (T/T: 18.5%, T/G: 20.2%, G/G: 36.7%; P < 0.05). LIF SNP T/G (rs929271) seems to be a susceptibility biomarker capable of predicting implantation efficiency and pregnancy outcomes.

Do Leukaemia Inhibitory Factor and Vascular Endothelial Growth Factor Have Any Roles in Intrauterine Device Mechanism of Action? An Experimental Rat Study

OBJECTIVE

To assess leukaemia inhibitory factor (LIF) and vascular endothelial growth factor (VEGF) expression as markers of intrauterine device (IUD) efficacy in a rat model.

METHODS

Twenty nulliparous female Wistar rats were divided into two groups with 10 animals per group: group I (IUD) and group II (control group, no IUD). In group I, a 2-cm 3-0 silk suture was placed into one horn of the rat bicornuate uterus. On day 20 (after IUD insertion) rats were sacrificed and their uteri removed. The number of vessels and the distribution of LIF and VEGF were compared among the uterine horns.

RESULTS

There were no significant differences in LIF and VEGF expression in the groups and all horns (p > 0.05). The number of vessels was higher in the IUD+ horn than in the IUD- horn of group I and in the horn of group II (p < 0.05). There was no significant difference in the number of vessels between the IUD- horns of groups I and II (p > 0.05).

CONCLUSION

LIF and VEGF expression did not correlate with IUD efficacy in a rat model. An IUD may increase the number of vessels in the uterine horn independent of VEGF expression. © 2015 S. Karger AG, Basel.

Intranuclear crosstalk between extracellular regulated kinase1/2 and signal transducer and activator of transcription 3 regulates JEG-3 choriocarcinoma cell invasion and proliferation

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.

LIF-STAT signaling and trophoblast biology

Leukemia inhibitory factor (LIF) is a pleiotropic growth factor that regulates several biological functions. This review focuses on the LIF-dependent STAT activation and its impact on modulation of trophoblast functions during embryo implantation. LIF is mainly produced by the maternal endometrium at the time of implantation while its receptors are present both on the endometrium and trophoblasts. It might influence blastocyst attachment through STAT3 activation and expression of integrins. After attachment of the blastocyst, trophoblasts undergo proliferation and differentiation into invasive EVTs and non-invasive STBs. Under in vitro conditions, LIF regulates all these processes through activation of STAT- and MAPK-dependent signaling pathways. The observations that LIF and STAT3 knockout mice are infertile further strengthen the notion about the critical involvement of LIF-mediated signaling during embryo implantation. Hence, a better understanding of LIF-STAT signaling would help in improving fertility as use of LIF in in vitro blastocyst culture improves the implanting ability of blastocyst after IVF.

Understanding the link between the IL-6 cytokine family and pregnancy: implications for future therapeutics

Cytokines are involved in almost all processes during the menstrual cycle, the fertilization period and pregnancy. They are expressed in numerous reproduction-related body fluids and tissues. Disorders of cytokine expression patterns may cause pregnancy pathologies. Therefore, cytokines have the potential as new biomarkers in different body compartments for a variety of such pathologies. Furthermore, cytokines may also serve to treat fertility and pregnancy disorders. The IL-6-like family of cytokines is an intensively investigated group of cytokines with well-accepted functions in fertility and pregnancy. This article summarizes current knowledge on IL-6-like cytokines in regard of their role in reproduction and their potential for new strategies in the treatment of reproductive pathologies.