Low-dose aspirin can downregulate progesterone resistance and increase the expression of LIF in endometriosis during the implantation window.

AIM: Study the effect of low-dose aspirin on the endometrial receptivity in endometriosis rat models. MATERIALS AND METHODS: This study is to explore the expressions of progesterone receptor and LIF among three groups of endometriosis rat models: control group (n = 12), EMs group (n = 15), and aspirin group (n = 17). The expressions of progesterone receptor (PR), PRA, PRB, and leukemia inhibitory factor receptor (LIFR) in eutopic endometrium were determined using immunohistochemistry technology, western blot, and qRT-PCR. The levels of LIF in eutopic endometrium and serum were detected by western blot, qRT-PCR, and ELISA. RESULTS: The expressions of PR, PRA, and PRB protein were significantly increased in the eutopic endometrium after low-dose aspirin treatment, and the level of PRB mRNA was also increased while the ratio of PRA/PRB mRNA was decreased in the eutopic endometrium. The levels of LIF in eutopic endometrium and serum were increased compared with the untreated endometriosis rats. However, the expression of LIFR was not statistically different among the three groups. CONCLUSIONS: The results suggest that the low-dose aspirin treatment could downregulate progesterone resistance and increase the expression of LIF of endometriosis rats during the implantation window, which could improve endometrial receptivity and enhance the pregnant rate of endometriosis. It may provide a potential treatment method for endometriosis-related infertility.

LIF and LIF­R expression in the endometrium of fertile and infertile women: A prospective observational case­control study.

The aim of the present study was to determine the expression of leukemia inhibitory factor (LIF) and LIF receptor (LIF­R) in the endometrium of fertile and infertile women during the implantation window. A prospective study was conducted between March 2013 and March 2015 at Iakentro, Infertility Treatment Center (Thessaloniki, Greece) and the 3rd Department of Obstetrics and Gynecology, Aristotle University of Thessaloniki (Thessaloniki, Greece). The patient group consisted of women diagnosed with infertility, whereas the control group consisted of women who had delivered at least one live newborn (fertile women). An endometrial biopsy was obtained using a Pipelle on day 7 or 8 post­ovulation, and the expression of LIF and LIF­R was assessed by immunohistochemistry in epithelial and stromal cells. Primary outcomes included positive cellular percentage, staining intensity and H­score. P<0.05 was considered to indicate a statistically significant difference. Overall, 45 women were included in the present analysis (15 fertile women and 30 infertile women). Mean age was 32.8±6.0 years for the fertile group, and 37.6±3.7 for the infertile group. LIF and LIF­R expression was significantly reduced in the epithelial cells of infertile women (P=0.05 and P=0.006, respectively). However, no significant differences were detected with regards to the expression of LIF in stromal cells (P=0.95). In addition, LIF­R expression was relatively higher in the stromal cells of the fertile group; however, the difference did not reach statistical significance (P=0.10). In conclusion, endometrial expression of LIF and LIF­R is significantly reduced in the epithelial cells of infertile women. Expression patterns of LIF­R in stromal cells require further research in order to achieve definitive results.

Expression of leukemia inhibitory factor in the rat retina following acute ocular hypertension.

The aim of the present study was to investigate the expression of leukemia inhibitory factor (LIF) and its downstream signaling pathways in the rat retina following acute ocular hypertension. The intraocular pressure of the rats was elevated to 110 mmHg for 1 h by infusing the anterior chamber with normal saline. The retinal tissues were obtained 12 h, 24 h, and 2, 3 and 7 days after termination of the ocular hypertension. Hematoxylin and eosin and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining were performed to assess the morphological changes and the apoptosis of retinal cells, respectively. Quantification of the retinal ganglion cells (RGCs) was performed using fluorogold retrograde (FG) staining. The expression levels of LIF, LIF receptor (LIFR), signal transducers and activators of transcription 3 (STAT3), phosphorylated STAT3 (P­STAT3), Akt, phosphorylated­Akt (P­Akt), extracellular signal­regulated kinase (ERK) and phosphorylated ERK (P­ERK) were determined at different time­points following acute ocular hypertension using western blot analysis. Reverse transcription­quantitative polymerase chain reaction was performned to detect the mRNA expression levels of LIF and LIFR. The results revealed that 12 h, 24 h, 2, 3 and 7 days after reperfusion, the thickness of the inner nuclear layer and the inner plexiform layer was decreased, with a significant reduction in the number of RGCs, as determined using TUNEL and FG staining. The expression levels of LIF and LIFR were increased following acute ocular hypertension. At 12 h post­retinal reperfusion, the expression levels of P­STAT3 and P­Akt were significantly upregulated, while the expression of P­ERK was decreased. The changes in the expression levels of LIF and LIFR suggested that LIF may be important in the process of degeneration/protection following retinal ischemia induced by acute ocular hypertension, via activation of the Janus kinase/STAT and Akt signaling pathways.

Effects of leukemia inhibitory factor on proliferation and odontoblastic differentiation of human dental pulp cells.

INTRODUCTION: The purpose of this study was to determine whether the leukemia inhibitory factor (LIF) is expressed in human dental tissue and exerts its effect on proliferation and odontoblastic differentiation of the dental pulp cells (DPCs). METHODS: An immunohistochemical assay was used to detect the expression of LIF and leukemia inhibitory factor receptor (LIFR) in the human dental pulp. The proliferation of DPCs was examined by culturing human primary DPCs in the presence of LIF with different doses or the neutralizing antibody to LIF. Western blot was performed to assay the phosphorylation of Janus kinase 2 (Jak2) and signal transducer and activator of transcription 3 (Stat3) in the presence or absence of LIF and/or AG 490, a specific inhibitor of Jak2. The odontoblastic differentiation of DPCs was determined using the alkaline phosphatase (ALP) activity assay, quantification of bone sialoprotein (BSP) and dentin sialophosphoprotein (DSPP) gene expression, and mineralization nodule formation. RESULTS: LIF and LIFR were present in the odontoblasts and DPCs. LIF induced proliferation of DPCs, which was inhibited by the LIF neutralizing antibody and AG 490. LIF induced phosphorylation of Jak2 and Stat3 but not in the presence of the AG490. ALP activity of DPCs, in the absence or presence of mineralization induction medium, was inhibited by LIF. Furthermore, the mineralization nodule formation and the expression of BSP and DSPP were inhibited by LIF. This inhibition on differentiation was attenuated by the AG490. CONCLUSIONS: LIF and LIFR are expressed in the human dental pulp. LIF promotes the proliferation of DPCs, and the odontoblastic differentiation is inhibited via the Jak2-Stat3 signaling pathway.

Proteomic analysis of proteins from bronchoalveolar lavage fluid reveals the action mechanism of ultrafine carbon black-induced lung injury in mice.

Previous studies have shown that ultrafine carbon black (ufCB) could cause oxidative stress and lung injury, but the mechanisms have not been clearly demonstrated. In this study, 1-D gel electrophoresis coupled with LC/MS/MS (1-D geLC/MS/MS) was carried out with bronchoalveolar lavage fluid (BALF) to identify proteins associated with ufCB-induced lung injury. If required, Western blot was conducted additionally to validate proteins. Thirty-three proteins were identified, including leukemia inhibitory factor receptor (LIFR) and epidermal growth factor receptor (EGFR). Western blot analysis showed that ufCB exposure caused the increases of LIFR and EGFR in BALF and decreases of both receptors in lung tissues, suggesting the acceleration of epithelial shedding from the lung and increase of cell debris with membrane proteins EGFR and LIFR in BALF. There were strong correlations between vascular endothelial growth factor (VEGF) and albumin (p<0.01) or alpha2-macroglobulin (alpha2M) in BALF (p<0.05). Importantly, antioxidant ceruloplasmin (Cp) was shown to be produced from lung epithelial cells in response to ufCB exposure. This is the first study to apply 1-D ge LC/MS/MS and experimental studies to reveal the mechanisms involved in the pathogenesis of ufCB-induced lung injury.