Body weight affects the risk of developing diabetes: between 80 and 90% of patients with type diabetes are overweight or are obese. Agreement for scientists of the Max Planck Institute for neurological Cologne research and the cluster of excellence in Cologne in cellular responses of diseases associated with aging (CECAD) stress, short RNA, called micro-ARNsemblent molecules play an important role in this mechanism.
Researchers have discovered that the shape of obese mice increase levels of the molecule of RNA regulatory miRNA-143. miRNA-143 inhibits the activation of the AKT enzyme stimulated insulin. Without active AKT, insulin cannot deploy its reduction of the effect of sugar in the blood and sugar in the blood is expelled from the other. This newly discovered mechanism can be the starting point for the development of new drugs for the treatment of diabetes.
Insulin plays a key role in the regulation of blood glucose. If there is too much glucose in the blood, insulin opens the glucose transport channels in the membrane of the muscle and fat cells. Glucose, then reaches the cells of the body and the content of the blood sugar sinks. In addition, insulin inhibits the production of sugar again in the liver. People with type 2 diabetes are capable of producing sufficient amounts of insulin; However, their cells are resistant to one - and the hormone is unable to perform its task. If untreated, this disease damages blood vessels due to high blood glucose levels which can lead to a heart attack or stroke.
Molecular processes in the cells of the body responsible for the connection between diabetes and weight are unknown. However, in all tissues that respond to insulin, Micro RNA, it can find. Diseases of aging at the University of Cologne in Cologne to take associated with scientists based in Cologne with Jens Brüning, Director at the Max Planck Institute for neurological Research Coordinator scientific excellence Cluster in cellular responses of stressd this micro RNA can also play a role 2 type diabetes. These short ribonucleic acid molecules can regulate the activity of genes, and thus control the production of proteins.
The research group of Cologne has to discover a new mechanism that leads to the cells insulin resistance. As a result, obese mice are excess miRNA-143 in the liver. This molecule silences of the RNA genes that are responsible for the activation of the AKT enzyme and therefore inhibit insulin activate AKT. "AKT is important for the transport of glucose into cells and inhibition of the synthesis of glucose in the liver." When its inhibited in the enzyme, insulin takes effect and the blood sugar remains high, explains Jens Brüning.""
For their study, published in Nature Cell Biology, the researchers compared mice of 2 type diabetes with normal weight obese mice. They discovered that sick animals more than two times more produce miRNA 143 in their livers than normal. In addition, researchers have discovered only a low concentration of ORP8 protein in obese mice that form large quantities of miRNA-143. ORP8 stimulates insulin to activate AKT and therefore reduced the sugar content in the blood. If there is a lack of ORP8, insulin is unable to take effect and inactive AKT.
Researchers don't know yet why obese mice are more than 143 miRNA than their normal weight counterparts. "If we succeed to the explanation of the signaling pathways in the cell that lead to the production of miRNA-143, we will have a starting point for the development of new drugs for the treatment of type 2 diabetes" explains Jens Brüning in reference to plans for future research.
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