Role of LIF/LIFR/STAT3 pathway in endometrial receptivity in rats with polycystic ovary syndrome / 西安交通大学学报(医学版)

【Objective】 To investigate the role of LIF/LIFR/STAT3 pathway in endometrial receptivity in rats with polycystic ovary syndrome (PCOS). 【Methods】 Forty 21-day-old SD female rats were divided into normal (control) group, model group, sham-operation group, and LIF group with 10 rats in each. The rat model of PCOS was constructed by subcutaneous injection of prasterone sodium sulfate at the back of the neck. The serum levels of testosterone (T), glucose and insulin in each group were detected. The morphological changes of the uterus in each group were observed by HE staining, and the morphological changes of endometrium were measured. Immunohistochemistry, Western blotting, and Real-time fluorescence quantitative PCR(qRT-PCR) were used to determine the protein expression and mRNA expression of LIF and STAT3 in rat endometrium. 【Results】 Compared with control group, the levels of integrin avb3, serum T, insulin and glucose in PCOS rats were significantly increased (P=0.000, P=0.000, P=0.001). Supplementation of exogenous LIF could significantly reduce the levels of integrin avb3, serum T, glucose and insulin in PCOS rats (P=0.000, P=0.002, P=0.003, P=0.007). HE results showed that exogenous LIF could reduce uterine cavity and glandular morphology in PCOS rats and increase the equivalent diameter (P=0.000, P=0.000) and area (P=0.000, P=0.000) of uterine glands and glandular cavity, the ratio of glandular interstitial area (P=0.000), and the average endometrial thickness (P=0.006), with statistically significant differences. Immunohistochemistry, Western blotting, and qRT-PCR results showed that the expression levels of LIF and p-STAT3 protein and mRNA in model group were significantly decreased compared with control group. Compared with model group, the protein and mRNA expressions of LIF and p-STAT3 in LIF group were significantly increased (P<0.05). 【Conclusion】 Exogenous LIF supplementation can improve endometrial receptivity in PCOS rats, and its mechanism is related to the LIF/LIFR/STAT3 pathway.

A LIF Mutation at The 29th Amino Acid Totally Abolished The Biological Functions / 生物化学与生物物理进展

Leukemia inhibitory factor (LIF) plays important roles in varieties of biological processes. This factor is highly conserved in mammalian animals and only one heterozygous LIF mutation was reported to cause the infertility of women. A LIF mutation was generated and the evidences were provided that the mutation of mature LIF at the 29th amino acid totally abolished its functions, including stimulation of STAT activation assayed by Luciferase reporter gene expression and EMSA experiments. In addition, the mutated LIF failed to inhibit the proliferation of M1 cells. The data indicated that the mutation of LIF did not have a dominant negative effect but lost the biological functions, suggesting that the 29th amino acid is critical for maintaining the activities of LIF.

Expression of leukemia inhibitory factor in osteoarthritic tissues in rabbits and human:an experimental and clinical study / 中华创伤骨科杂志

Objective To investigate the regulation expression of leukemia inhibitory factor(LIF)in hu- man and animal osteoarthritic(OA)tissues and its clinical relevance.Methods 1)Thirty-five Japanese rabbits, aged eight months,were used to make models of experimental osteoarthritis.Operations were performed at the right knee and the sham ones at the left knee in each rabbit.Rabbits were sacrificed on the 3,7,14,28,42,56 and 84 days after operation respectively.Cartilage and synovium of the knee were collected to observe histological changes of osteoarthritis at different times;immunohistochemistry analysis was conducted to observe the LIF expression and distribution in the cartilage and synovium of the animals.2)From April 2003 to October 2003,32 samples of human articular tissues(cartilage,subchondral bone and synovium)were obtained in the operational procedures and a good quantity of RNA was isolated using Magnetic Beads.The patients who underwent articular operations donated the samples.In the reverse transcription-polymerase chain reaction(RT-PCR),the mRNA expression of LIF was mea- sured by semi-quantity analysis and the location of LIF protein was determined by enzyme-linked immunosorbent assay (ELISA).Results A slight expression of LIF was seen in normal cartilage but less in synovium.However,the expression of LIF was remarkable in synovial lining cells,superficial and middle layers of cartilage in animal os- teoarthritis.There was a significant difference in expression between the animal osteoarthritis and the control group (P＜0.05 ).In human tissue study,LIF mRNA was expressed to a very low level in normal articular tissues and there was no significant difference(P＞0.05)between different anatomical locations.In moderate degrading sub- chondral bone,LIF mRNA was expressed to its highest level.LIF was expressed to the highest level in seriously degrading cartilage tissues.The results were similar to ELISA testing results.LIF extents varied in different articular tissue sections.Conclusions LIF is an important mediator that can contribute to tbe pathogenesis of OA.The different temporal and spatial distributions of LIF in normal and OA tissues imply that LIF may play some important roles in pathogenesis of OA.

Expressions of Leukemia Inhibitory Factor (LIF): Comparison of Normal Pregnancy and Recurrent Abortion / 대한산부인과학회잡지

OBJECTIVE: Successful implantation depends on a complex interaction between the developing blastocyst and the endometrium. Among the steroid hormones, growth factors, and cytokines which participate in preparing the uterus for implantation, leukemia inhibitory factor (LIF) plays an essential role in implantation. We compared the expression of LIF in normal pregnancies to that of recurrent abortions in placenta to elucidate whether spontaneous abortion and expression of LIF has correlation. METHODS: Placental tissues from normal pregnancies and recurrent abortions were fixed and embedded in paraffin. Standard immunohistochemical staining was used to identify LIF. RESULTS: LIF expressions on cytotrophoblast of recurrent abortion were lower than those of normal pregnancy. There were no expressions on syncytiotrophoblast and stroma in the both groups. In the decidua and gland, LIF was expressed in mild degree and there were no differences in LIF expression between normal pregnancy and recurrent abortion. CONCLUSION: LIF expression on cytotrophoblast of recurrent abortion was lower than that of normal pregnancy. LIF may provide paracrine and autocrine signals to both embryonic tissues and uterine epithelium during implantation. The dysfunction of LIF production may be a cause of the unexplained recurrent abortions.

Expression of Leukemia Inhibitory Factor (LIF) in the Clomiphene Citrate Treated Infertile Women with Luteal Phase Defect / 대한산부인과학회잡지

OBJECTIVE: Although the regulation of implantation is not clearly understood, recent studies have revealed that many cytokines and growth factors play an essential role in preimplantation endometrial development. Among the cytokines, the expression of leukemia inhibitory factor (LIF) is absolutely essential for implantation, although its precise role is not fully understood. Clomiphene citrate is most commonly used drug in the treatment of infertility, but pregnancy rate achieved with clomiphene citrate is significantly lower than the ovulation rate due to the antiestrogenic effect of it on the cervical mucus and endometrium. The our purpose was to evaluate the endometrial expression of LIF in clomiphene citrate treated infertile women with luteal phase defect and association of clomiphene citrate and unsatisfactory endometrial development. METHODS: The endometrial samples from women with luteal phase defect (n=27) were examined. The endometrial tissue was obtained during secretory phase in 5 cases, and during proliferative phase in 6 cases without clomiphene citrate treatment. In 16 cases, the endometrial tissue was obtained by biopsy during secretory phase after clomiphene citrate treatment. Immunohistochemical staining was performed for LIF in the endometrial tissues. And then the expression of LIF was compared between clomiphene citrate treatment group and no treatment group during secretory phase, and secretory and proliferative phase were compared in the no treatment group. RESULTS: The endometrial expression of LIF was not significantly different between clomiphene citrate treated group and no treated group (p. value=0.123) and between proliferative phase and secretory phase without clomiphene citrate (p. value=0.306). The expressions of LIF were detected mostly in glandular epithelial cells and not in the stromal cells. CONCLUSION: We demonstrated that LIF was expressed in glandular epithelial cells rather than stromal cells and there was not menstrual cycle dependent difference of endometrial expression of LIF in infertile women with luteal phase defect. And our finding suggested that clomiphene citrate did not affect the secretory phase endometrial expression of LIF in infertile women with luteal phase defect.

Effects on Myoblast Proliferation by Fibroblast Growth Factor, Leukemia Inhibitory Factor and Interleukin-1

OBJECTIVE: Recently, cultured myoblast transplantation has been extensively studied as a gene complementation approach in such genetic diseases as Duchenne muscular dystrophy (DMD). In the present work we investigated the stimulating effects of the growth factors, such as basic fibroblast growth factor (bFGF), leukemia inhibitory factor (LIF) and interleukin-1 (IL-1), on growth rate and differentiation of myoblast. METHOD: Human myoblasts were cultured from biopsy and treated in vitro with various concentration of bFGF, LIF and IL-1. In serum-free defined medium the following observation were made to evaluate differentiation. RESULTS: bFGF and LIF except IL-1 were found to have stimulating effect of myoblast proliferation comparing to control group (p<0.05), yet there were no statistically significant differences among each growth factors (p<0.05). The most significant growth stimulation of myoblasts in culture was achieved by adding 3.0 ng/ml of bFGF, producing a stimulation effect up to 2.01-fold. All myoblasts treated with growth factors differentiated into myotube. CONCLUSION: Our findings indicate that bFGF and LIF stimulate the proliferation of myoblast, which may result in an effective way in producing large numbers of myoblasts for clinical myoblast transplantation in DMD patients.