Definition of adiponectin

Adiponectin (ADPN) is an endogenous bioactive polypeptide or protein secreted by adipocytes. Adiponectin (ADPN) is an endogenous bioactive polypeptide or protein secreted by adipocytes. Adiponectin is an insulin-sensitizing hormone (An Insulin-sensitizing Hormone), can improve the mice's insulin resistance (Insulin resistance) and atherosclerosis; study of the human body found that adiponectin levels can predict type II diabetes And the development of coronary heart disease, and in clinical trials show anti-diabetic, anti-atherosclerotic and inflammatory potential.

An overview of adiponectin

The researchers found a new compound that regulates adiponectin, which provides a new way to study the mechanism of adiponectin function and insulin sensitivity. Insulin is secreted by the pancreas of hormones, the main function is to promote blood glucose into the muscle or adipose tissue, providing the body with the energy required. When insulin can not play a role, the blood glucose can not be transformed into the body's energy requirements, leading to elevated blood sugar, diabetes occurs. The insulin resistance refers to the cells can not effectively use insulin and even insulin response is no longer sensitive, this is the most important cause of diabetes. Scientists believe that the release of free fatty acids and certain fat molecules is the culprit of insulin resistance. Lily Dong and her collaborators have been searching for cellular proteins associated with adiponectin receptors to discover new targets for regulating adiponectin hormone function. They identified a multi-domain protein that regulates the function of adiponectin in fatty acid oxidation and glucose uptake and named the new protein APPL1. They further demonstrated that in muscle cells, APPL1 regulates the insulin-sensitive effects of adiponectin through the kinase pathway.

Biochemical characteristics of adiponectin

Adiponectin is one of the most abundant protein products in adipose tissue, which is found in a large number of blood products. In the human body in the concentration of 3-30ug / ml in circulating plasma. Adiponectin is also known as Acrp30, apM1, AdipoQ, GBP28, initially, adiponectin in human subcutaneous adipose tissue, plasma and murine animal fat cells were found. Adiponectin from the body consists of 244 amino acids, molecular weight of 30KD. From the amino-terminal secretion signal sequence (aa 1-18), a specific sequence (aa19-41), a group of 22 amino acids consisting of collagen repeat (Aa 42-107), a segment of a spherical sequence (aa108-244). The globular region is a key site for the biological activity of adiponectin. Similar to the structure of TNF-α, adiponectin is highly homologous to collagen Ⅷ, X and complement C1q. Adiponectin is a biologically active form or receptor affinity ligand that specifically binds to the G protein-coupled receptor type I or II adiponectin receptor on skeletal or hepatic cell membranes , Thereby regulating fatty acid oxidation and glucose metabolism.

The role of adiponectin

Kondo and other extensive genome scan found that type 2 diabetes and metabolic syndrome susceptibility locus on chromosome 3q27, which is the site of adiponectin gene. They screened a subset of Japanese patients with type 2 diabetes and matched controls with age and body mass index, analyzed their adiponectin gene mutations, and identified four missense mutations in the globular region of adiponectin (R112C, I164T, R221S and H241P), which were present in heterozygous form. The frequencies of I164T mutations in patients with type 2 diabetes were significantly higher than those in the control group (P <0.01). Moreover, patients with I164T mutations had lower concentrations of adiponectin than those without such mutations, and all patients with this mutation showed signs of metabolic syndrome, including hypertension, high blood pressure Lipidemia, diabetes, arteriosclerosis. Through enzyme-linked immunosorbent assay study found that I164T and R112C mutation and low plasma adiponectin concentrations and type 2 diabetes. The genetic polymorphism of the adiponectin gene, leading to decreased production and secretion of adiponectin, at least partly explains the pathophysiology of insulin resistance syndrome. The analysis and detection of adiponectin genes are of great help in developing drugs that are specific to diabetes, including selecting the most effective treatment principles for each individual and providing drugs specific to their genetic information. To further explore the relationship between adiponectin, obesity, insulin sensitivity, insulinemia and glucose tolerance, Weyer and other obese and type 2 diabetes tend to 23 Caucasian and 121 Indian plasma lipid The concentrations of adiponectin, body fat, insulin sensitivity and glucose tolerance were measured. Confirming that obesity and type 2 diabetes are associated with low plasma adiponectin concentrations in different racial populations, suggesting that hypoadiponectinemia is more closely associated with obesity and glucose tolerance than insulin resistance and hyperinsulinemia. There is increasing evidence that adiponectin and its synthetic synergies are of value in the treatment of type 2 diabetes and metabolic syndrome associated with insulin resistance. Recent studies have reported that the rapid administration of cut-off adiponectin in the body reduces postprandial plasma free fatty acids in mice fed a high-fat diet. If administered slowly, the mice will lose weight without affecting their food intake. Scherer and his associates have also demonstrated rapid injection of recombinant adiponectin, which will completely improve hyperglycemia in several animal models of diabetes, including ob / ob mice, nonobese diabetic mice, and streptozotocin-treated mouse.