The Effect Of Early Over-Nutrition On Renin-Angiotensin System In Adipose Tissue: A Preliminary Study

Part I The effect of early over-nutrition on expression of angiotensin- converting enzymes(ACE, ACE2) in rat adipose tissueObjective: This study aimed to analyze the gender-specific effect of angiotensinconverting enzyme in adipose tissue and obesity of offspring after early over-nutrition exposure, then to discuss the mechanism and gender-specific effect of nutrition programming.Methods:(1) Pregnant female SD rats were fed with high-fat diet or normal litter and continued on their respective diets after giving birth to pups until pups weaned. The highfat diet group in the perinatal period is the pups whose mothers were weaned to a high-fat diet. The normal litter group in the perinatal period is the pups whose mother were weaned to a control diet.(2) Glucose tolerance test of the offspring at 21 day of age were assessed. Blood glucose, serum triglyceride, cholesterol was detected in rats by using enzymatic method and serum insulin levels by radioimmunoassay.(3) Subcutaneous and retroperitoneal adipose tissue was harvested from offspring. Real-time PCR, Western blot was used respectively to measure the gene and protein expression level of angiotensinconverting enzyme(ACE) and angiotensin-converting enzyme 2(ACE2) in adipose tissue.Results:(1) Rats which were fed with high-fat diet in the perinatal period were associated with high body weight(p<0.05) and adipose tissue weight(p<0.001).(2) At three weeks of age, the high-fat diet male offspring showed no significant difference(p>0.05) in the concentration of serum triglyceride, cholesterol, insulin, glucose with normal litter, but blood glucose levels were significantly higher than normal litter after the glucose tolerance test(p<0.05). There were no significant differences(p>0.05) in terms of the concentration of serum triglyceride, cholesterol, insulin, glucose and glucose tolerance test between two female groups.(3) In the high-fat diet male group, ACE, ACE2 m RNA and protein expression were increased significantly in retroperitoneal adipose(p<0.05) and no significant differences(p>0.05) in subcutaneous adipose compared with the normal diet male group at 21 days of postnatal age.(4) In the high-fat diet female group, ACE m RNA and protein expression were similar(p>0.05), but ACE2 m RNA and protein expression were increased significantly(p<0.05) in retroperitoneal adipose compared with the normal diet female group at 21 days of postnatal age. Moreover, ACE, ACE2 m RNA and protein expression were similar in two female groups in subcutaneous adipose(p>0.05).Conclusion:(1) The high-fat diet in perinatal period induced obesity in male and female offspring, but the male show worse outcome by early over-nutrition compared with the female rats.(2) There were a gender-specific ACEs expression n the adipose tissue, and it may be involved in different outcome after early over-nutrition exposure.(3) The highfat diet in perinatal period increased the degration of renin-angiotensin system(RAS) in visceral adipose tissue, which may be a protective role.Part Ⅱ Analysis genes of vascular endothelial dysfunction and obesity genes and construct related signaling pathway by systems biologyObjective: This study aimed to analyze the genes between endothelial dysfunction and obesity, then to construct their significant signaling pathway, further to illustrate the significance of systems biology in the clinical study.Methods: The statistical significant genes about vascular endothelial dysfunction and obesity were exacted from Pubmed database by searching keywords as follows: “polymorphism”, “gene”, “genetic”, “allele”, “genotype”, “genetics”, “genome” combined with “endothelial function”, “endothelium” and “obesity”, “adiposis”, “adipositas”, “adiposity”, “fat”. STRING software was used to analyze the association between these statistically significant genes. DAVID software was used to annotate function of these candidate genes, including gene function categories, signaling pathway and so on. Gene Go Meta Core software was used to identify related informatics pathways of these significant genes.Results: 142 genes associated with obesity do play a role in endothelial dysfunction in Pubmed database. According to the results of STRING software, there is a close connection between these proteins, what is more, AGT, ACE, ACE2, AGTR1, AGTR2 protein contact more closely with the rest of these proteins. The results of DAVID software show these genes are associated with diabetes, lipid metabolism, cholesterol metabolism and so on. At last, a significant pathway(protein folding and maturation_angiotensin system) associated with obesity and endothelial dysfunction was explored by Gene Go Meta Core software.Conclusion:(1) This paper enrichs the signaling pathway of protein folding and maturation_angiotensin system(RAS) through systems biology firstly, which plays a very important role in obesity and cardiovascular diseases.(2) The pathway of RAS could serve as a target for prevention and treatment in the futrue.