The Association Of CIDE-B Gene Promoter Methylation And M Rna Expression With Overweight Or Obesity

Objective: The aims of this study detect the methylation level of CIDE-B gene promoter sequence together with the mRNA expression level in subcutaneous adipose layers and omental adipose tissues in overweight or obesity group and normal group,and explore the association between the methylation level of CIDE-B gene promoter and obesity as well as the association between mRNA expression level and obesity.Methods: According to the Chinese diagnose criteria, groups were defined as overweight or obesity group(BMI≥24kg/m) and normal group(18.5≤BMI﹤24kg/m).Subjects with abdominal operation in hospital were enrolled in this study. Height,weight, waist circumference, hip circumference together and general biochemical indicators were tested before operation. Pregnant women, adult patients suffering from disability or spirit obstacles, secondary obese, malignant tumor and history of infectious diseases(such as hepatitis B, acquired immune deficiency syndrome and tuberculosis, etc.) were excluded. The Promoter methylation level of a total of 116 patients including overweight or obesity group(n=66) and normal weight group(n=50) was detected by mass spectrometry. Two milliliters fasting venous blood was collected in the morning and then placed in anticoagulant EDTA-K2 tube. After the centrifugation at full speed(3000rpm) for 10 min, the plasma was kept frozen at-80℃refrigerator until analyses were conducted. The mRNA expression level of a total of106 patients including overweight or obesity group(n=60) and normal weight group(n=46) was detected by real time PCR. They were operated under general anesthesia,during which 2g subcutaneous adipose layers and omental adipose tissues were respectively taken out of the peritoneal and swashed by sterile salt water instantly,then placed in the tube and stored in liquid nitrogen. All data was analyzed by IBM SPSS Statistics 21.0, difference between groups by using two independent t sample t test or Mann-Whitney U test, enumeration data by using chi-square test, and significance level α=0.05.Results:1. Twenty one CpG sites methylation levels of CIDE-B gene promoter sequence were validly detected by squenome mass spectrometry in this study. There were no statistical differences in the CpG sites methylation levels between normal group and overweight or obesity group(P>0.05). Cp G4.5 was at the highest methylation level(0.65±0.06), and Cp G15 was at the lowest level(0.04±0.05). Cp G14 site methylation level of CIDE-B gene(b=-51.60, P<0.05) had relationship with BMI in overweight or obesity group, and gender(b=-0.05, P<0.05) and Cp G30 site methylation level of CIDE-B gene( b =-1.15, P<0.05) had relationship with waist-to-hip ratio in overweight or obesity group.2. The relative expression of CIDE-B gene mRNA in the subcutaneous adipose layers was 1.93 times higher than the expression in omental adipose tissues(subcutaneous adipose layers △Ct= 2.34 ± 1.80, omental adipose tissues △Ct= 1.40 ±1.04). There was statistical difference between two groups(t=4.52, P<0.05). Relative expression of CIDE-B gene mRNA in subcutaneous adipose layers of 60 overweight or obesity patients was 0.84 of the expression in the normal group(normal group△Ct= 0.88 ± 1.48, overweight or obesity group △Ct= 1.14 ± 1.16, there was nostatistical difference t=1.54,P>0.05). Relative expression of CIDE-B gene mRNA in omental adipose tissues of 60 overweight or obesity patients was 1.72 times higher than the expression in 46 normal patients(normal group △Ct= 2.22 ± 1.55, overweightor obesity group △Ct=1.44 ± 0.99). There was statistical difference(t=-2.38, P<0.05).3. Relative expression of this gene in the patients whose diastolic blood pressure was higher than 80 mm Hg was 1.01 times higher than subjects whose diastolic blood pressure was lower than 80 mm Hg in omental adipose tissues and there was statistical difference(P<0.05). Relative expression of this gene in the patients with higher TG was 1.20 times higher than subjects with lower TG in the subcutaneous adipose layers and there was statistical difference(P<0.05). Relative expression of this gene in the patients with higher HDL was 0.76 of the patients with lower HDL and there was statistical difference(P<0.05). Relative expression of this gene in the patients with higher LDL was 1.11 times higher than patients with lower LDL and there was statistical difference(P<0.05);4. Cp G19 methylation level influenced the expression of target gene mRNA in the omental adipose tissues and there was statistical difference(b=-14.82, P<0.05),Cp G2 methylation level influenced the expression of target gene mRNA in the subcutaneous adipose tissues and there was statistical difference(b=-14.82, P<0.05).Conclusion: Some sites of CIDE-B gene promoter sequence were abnormal methylated. The higher of methylation level, BMI and WHR would be lower. High expression of CIDE-B gene could increase TG and LDL and reduce HDL. The quantitative expression of CIDE-B gene mRNA in the overweight or obesity group was higher than normal group in the omental adipose tissues. It means that visceral fat tissue accumulation may have close relationship with obesity. The lower of CIDE-B gene promoter methylation level, the quantitative expression of target gene mRNA would be higher.