Targets Selection And Study On Molecular Mechanism Of Gestational Diabetes Mellitus

Gestational diabetes mellitus(GDM)is defined as occurrence of impaired glucose tolerance or elevated blood glucose levels in pregnant women who are unable to compensate for physiological change due to antagonistic insulin substance increases during pregnancy.GDM is one of the most common complications of pregnancy,which seriously threatens the health of pregnant women and their offspring.The effects on mothers included Excessive amniotic fluid,microvascular disease,impaired organ function during perinatal period,increased risk of type ? diabetes,obesity and other metabolic syndromes in later life.The influence of fetus includes fetal macrosomia,fetal growth restriction,fetal distress,even intrauterine fetal death and easy to develop metabolic disorder disease in later life.Presently,the pathogenesis of GDM has large unknown.Therefore,establish a stable experimental animal model of gestational diabetes,combined with clinical cases,in-depth study of GDM and its pathological mechanism in pregnant women,to find sensitive and reliable biochemical indicators,early detection and effective diagnosis of GDM pregnant women Interventions and treatments,and early intervention in high-risk GDM pregnant women,have important clinical and health implications.The research content of this paper is as follows:(1)Two animal models were established to screen molecular targets.Firstly,female mice were fed high-fat-diet(HFD)for a long time before pregnancy,which showed different degrees of metabolic disorders and reproductive dysfunction.Secondly,an animal model that was fed with HFD during pregnancy,which showed different degrees of glucose tolerance impaired,accompanied by insulin tolerance impaired,and the serum insulin level increased significantly.Mouse model induced by high fat diet during pregnancy is more suitable for GDM study.Then,we collected the white adipose tissue and placenta tissues on the 18 th day of pregnancy for microarray testing,and screened the metabolic targets based on the microarray data of immature female mice fed with long-term HFD in the early stage.A series of candidate research genes were screened,including chemerin and its receptor GPR1,osteoprotegerin(OPG).(2)GPR1 signaling could impact the blood glucose homeostasis on mice fed with high fat during pregnancy.The levels of chemerin and GPR1 regular increased in serum and placenta of pregnant mice,respectively.There were an increased chemerin levels in serum and a decreased GPR1 expression in placental mice fed with HFD compared with chow.The level of GPR1 protein and gene were significantly decreased in placenta of GDM patients.Therefore,we hypothesized that GPR1 signaling pathway may be involved in the pathogenesis of GDM.We used GPR1 small interfering RNA(siGPR1)or negative control(NC)to study the role of GPR1 in blood glucose homeostasis during pregnancy in mice.GPR1 knockdown aggravates glucose intolerance,disrupts lipid metabolism,and reduces ?-cell proliferation and serum insulin levels.GPR1 regulates the expression of glucose transporter 3(GLUT3)and FABP4 through phosphorylated AKT(pAKT)pathway.(3)GPR1,a metabolic target receptor,is involved in the regulation of choriocarcinoma.The expression of GPR1 in choriocarcinoma cells(JEG3 and BeWo)was significantly higher than that in normal trophoblasts(HTR-8/SVneo)by measuring GPR1 expression in several trophoblast cell lines.GPR1 knockdown inhibited the Akt,ERK phosphorylation,proliferation,and invasion of choriocarcinoma cell lines in vitro and slowed down the growth of tumors in vivo.On the contrary,overexpression of GPR1 promoted proliferation and invasion of choriocarcinoma cell lines in vitro.After then,we synthesized,selected and identified A 7-amino acid peptide(LRH7-G3)that specifically binds to GPR1 and antagonizes the GPR1 pathway by phage display identification,which can also inhibit the growth of choriocarcinoma in vivo and in vitro.(4)OPG could regulate blood glucose homeostasis on mice fed with high fat during pregnancy.OPG expression levels were elevated in serum and placenta of GDM patients.Meanwhile,OPG expression was evaluated on pregnant mice.Then,to investigate the effect of placenta-derived OPG on metabolic homeostasis during pregnancy,a placenta-specific OPG overexpression mouse was established to by transfecting blastocyst trophoblast cells with lentivirus.Results indicated that placentaderived OPG could regulate metabolism homeostasis,including reducing fetal weight,promoting glucose tolerance,increasing the proliferation of ?-cell and serum insulin level in HFD-induced GDM mice.In summary,it showed obviously impaired glucose tolerance and insulin tolerance on mice fed with HFD during pregnancy,which was close to clinical diagnostic standard.During pregnancy,GPR1 signaling might be involved in the regulation of blood glucose by regulating islet beta cells the function of proliferation and secretion,and placental glucose transport.Placenta-derived OPG could participate in the regulation of gestational blood glucose homeostasis through promoting islet ? cell function by the peripheral circulation system.In addition,our study is the first to report that GPR1 could regulate the development of choriocarcinoma through Akt and ERK pathways and may be a potential drug target for choriocarcinoma.