ABSTRACT
Melatonin receptor 1B (MT2, encoded by the MTNR1B gene), a high-affinity receptor for melatonin, is associated with glucose homeostasis including glucose uptake and transport. The rs10830963 variant in the MTNR1B gene is linked to glucose metabolism disorders including gestational diabetes mellitus (GDM); however, the relationship between MT2-mediated melatonin signaling and a high birth weight of GDM infants from maternal glucose abnormality remains poorly understood. This article aims to investigate the relationship between rs10830963 variants and GDM development, as well as the effects of MT2 receptor on glucose uptake and transport in trophoblasts. TaqMan-MGB (minor groove binder) probe quantitative real-time polymerase chain reaction (qPCR) assays were used for rs10930963 genotyping. MT2 expression in the placenta of GDM and normal pregnant women was detected by immunofluorescence, western blot, and qPCR. The relationship between MT2 and glucose transporters (GLUTs) or peroxisome proliferator-activated receptor γ (PPARγ) was established by western blot, and glucose consumption of trophoblasts was measured by a glucose assay kit. The results showed that the genotype and allele frequencies of rs10830963 were significantly different between GDM and normal pregnant women (P<0.05). The fasting, 1-h and 2-h plasma glucose levels of G-allele carriers were significantly higher than those of C-allele carriers (P<0.05). Besides, the protein and messenger RNA (mRNA) expression of MT2 in the placenta of GDM was significantly higher than that of normal pregnant women (P<0.05). Melatonin could stimulate glucose uptake and GLUT4 and PPARγ protein expression in trophoblasts, which could be attenuated by MT2 receptor knockdown. In conclusion, the rs10830963 variant was associated with an increased risk of GDM. The MT2 receptor is essential for melatonin to raise glucose uptake and transport, which may be mediated by PPARγ.
Subject(s)
Female , Humans , Pregnancy , Blood Glucose/metabolism , Diabetes, Gestational/metabolism , Glucose/metabolism , Melatonin/metabolism , Polymorphism, Genetic , PPAR gamma , Receptor, Melatonin, MT2/geneticsABSTRACT
Objective@#To explore whether the pro-inflammatory effect of endoplasmic reticulum stress in placental tissues involves in the genesis of gestational diabetes mellitus (GDM).@*Methods@#Forty gravidas who underwent regular prenatal examinations and delivered at Tongji Hospital were recruited from January to December, 2016. Among them, 20 were GDM women (GDM group), and the remaining twenty were served as the control, which were selected from those without GDM and matched for age and gestational weeks to the GDM group. Placental tissues were collected from the two groups. The ultrastructure of endoplasmic reticulum in trophoblast cells was observed under transmission electron microscope. The expression of glucose-regulated protein-78 (GRP-78), a marker protein for endoplasmic reticulum stress, and C/EBP homologous protein (CHOP) were detected using Western blotting. Five placental tissue samples were collected from normal gravidas for explant culture. Three subgroups were set up according to different culturing methods including culturing with IL-1β (5 ng/ml) for 20 h (IL-1β model group), 30 μmol/L thapsigargin (TG, an endoplasmic reticulum stress agonist) for 2 h after treating with IL-1β (5 ng/ml) for 18 h (IL-1β+TG intervention group) or with no stimulation (blank control group). Western blotting was used to detect the expressions of GRP-78, CHOP and glucose transporter 4 (GLUT4) in placenta explants. The mRNA expressions of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) were determined by real-time fluorescence quantitative polymerase chain reaction (RT-PCR). Statistical analysis was performed using one-way analysis of variance, LSD and t test.@*Results@#(1) In the GDM group, increased number and size of endoplasmic reticulum cisternae were observed in trophoblast cells. Moreover, obviously dilated endoplasmic reticulum and different size of fragments and vesicles were also seen under electron microscope. While the endoplasmic reticulum in the placental tissues of the control group showed no obvious swelling. (2) The expression of GRP-78 and CHOP protein in the GDM group were higher than those in the control group (0.90±0.17 vs 0.48±0.08, t=2.24; 0.85±0.13 vs 0.46±0.12, t=2.10; both P<0.05). (3) Compared with the blank control group, the expression of GRP-78 and CHOP protein in the IL-1β model group increased significantly (0.87±0.18 vs 0.36±0.07, t=2.67; 1.14±0.09 vs 0.78±0.06, t=3.20; both P<0.05); but the expression of GLUT4 protein significantly decreased (1.00±0.14 vs 2.21±0.49, t=2.40, P<0.05); the expressions of IL-6 and TNF-α mRNA significantly increased (0.89±0.23 vs 0.30±0.06, t=2.31; 0.62±0.16 vs 0.17±0.09, t=2.29; both P<0.05). Compared with the IL-1β model group, the expression of GRP-78 and CHOP protein significantly increased in IL-1β+TG group (2.02±0.32 vs 0.87±0.18, t=3.11; 2.18±0.31 vs 1.14±0.09, t=3.16; both P<0.05); the expression of GLUT4 protein significantly decreased (0.39±0.19 vs 1.00±0.14, t=2.66, P<0.05); the expression of IL-6 and TNF-α mRNA increased significantly (1.67±0.25 vs 0.89±0.23, t=2.26; 1.42±0.27 vs 0.62±0.16, t=2.51; both P<0.05).@*Conclusions@#Endoplasmic reticulum stress may be associated with increased release of pro-inflammatory cytokines in placental tissues of some GDM women and involved in the onset and development of GDM.
ABSTRACT
Objective To explore whether the pro-inflammatory effect of endoplasmic reticulum stress in placental tissues involves in the genesis of gestational diabetes mellitus (GDM). Methods Forty gravidas who underwent regular prenatal examinations and delivered at Tongji Hospital were recruited from January to December, 2016. Among them, 20 were GDM women (GDM group), and the remaining twenty were served as the control, which were selected from those without GDM and matched for age and gestational weeks to the GDM group. Placental tissues were collected from the two groups. The ultrastructure of endoplasmic reticulum in trophoblast cells was observed under transmission electron microscope. The expression of glucose-regulated protein-78 (GRP-78), a marker protein for endoplasmic reticulum stress, and C/EBP homologous protein (CHOP) were detected using Western blotting. Five placental tissue samples were collected from normal gravidas for explant culture. Three subgroups were set up according to different culturing methods including culturing with IL-1β (5 ng/ml) for 20 h (IL-1β model group), 30 μmol/L thapsigargin (TG, an endoplasmic reticulum stress agonist) for 2 h after treating with IL-1β (5 ng/ml) for 18 h (IL-1β+TG intervention group) or with no stimulation (blank control group). Western blotting was used to detect the expressions of GRP-78, CHOP and glucose transporter 4 (GLUT4) in placenta explants. The mRNA expressions of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) were determined by real-time fluorescence quantitative polymerase chain reaction (RT-PCR). Statistical analysis was performed using one-way analysis of variance, LSD and t test. Results (1) In the GDM group, increased number and size of endoplasmic reticulum cisternae were observed in trophoblast cells. Moreover, obviously dilated endoplasmic reticulum and different size of fragments and vesicles were also seen under electron microscope. While the endoplasmic reticulum in the placental tissues of the control group showed no obvious swelling. (2) The expression of GRP-78 and CHOP protein in the GDM group were higher than those in the control group (0.90±0.17 vs 0.48±0.08, t=2.24; 0.85±0.13 vs 0.46±0.12, t=2.10; both P＜0.05). (3) Compared with the blank control group, the expression of GRP-78 and CHOP protein in the IL-1β model group increased significantly (0.87±0.18 vs 0.36±0.07, t=2.67; 1.14±0.09 vs 0.78±0.06, t=3.20;both P＜0.05); but the expression of GLUT4 protein significantly decreased (1.00±0.14 vs 2.21±0.49, t=2.40, P＜0.05); the expressions of IL-6 and TNF-α mRNA significantly increased (0.89±0.23 vs 0.30±0.06, t=2.31;0.62±0.16 vs 0.17±0.09, t=2.29; both P ＜ 0.05). Compared with the IL-1β model group, the expression of GRP-78 and CHOP protein significantly increased in IL-1β+TG group (2.02±0.32 vs 0.87±0.18, t=3.11;2.18±0.31 vs 1.14±0.09, t=3.16; both P ＜ 0.05); the expression of GLUT4 protein significantly decreased (0.39±0.19 vs 1.00±0.14, t=2.66, P＜0.05); the expression of IL-6 and TNF-α mRNA increased significantly (1.67±0.25 vs 0.89±0.23, t=2.26; 1.42±0.27 vs 0.62±0.16, t=2.51; both P ＜ 0.05). Conclusions Endoplasmic reticulum stress may be associated with increased release of pro-inflammatory cytokines in placental tissues of some GDM women and involved in the onset and development of GDM.
ABSTRACT
Preeclampsia (PE) is a pregnancy-specific, multi-system disorder and the leading cause of maternal and perinatal morbidity and mortality in obstetrics worldwide. Excessive vasoconstriction and dysregulated coagulation function are closely associated with PE. Heat shock protein 20 (HSP20) is ubiquitously expressed under normal physiological conditions and has important roles in vascular dilatation and suppression of platelet aggregation. However, the role of HSP20 in the pathogenesis of PE remains unclear. In this study, we collected chorionic plate resistance arteries (CPAs) and serum from 118 healthy pregnant women and 80 women with PE and detected the levels of HSP20 and its phosphorylated form. Both HSP20 and phosphorylated HSP20 were downregulated in CPAs from women with PE. Comparison of the vasodilative ability of CPAs from the two groups showed impaired relaxation responses to acetyl choline in preeclamptic vessels. In addition to the reduced HSP20 in serum from women with PE, the platelet distribution width and mean platelet volume were also decreased, and the activated partial thromboplastin time and thromboplastin time were elevated.With regard to the vital roles of HSP20 in mediating vasorelaxation and coagulation function, the decreased HSP20 might contribute to the pathogenesis of PE.