According to scientists at the Max Planck Institute for Neurological Research in Cologne and the Cologne Cluster of Excellence in Cellular Stress Responses in Aging-associated Diseases (CECAD), short ribonucleic acid molecules, known as micro-RNAs, appear to play an important role in this mechanism.
The researchers discovered that the obese mice form increased levels of the regulatory RNA molecule miRNA-143. miRNA-143 inhibits the insulin-stimulated activation of the enzyme AKT. Without active AKT, insulin cannot unfold its blood-sugar-reducing effect and the blood sugar level is thrown out of kilter. This newly discovered mechanism could provide the starting point for the development of new drugs for the treatment of diabetes.
The hormone insulin plays a key role in the regulation of blood sugar levels. If there is too much glucose in the blood, insulin opens the glucose transport channels in the cell membrane of muscles and fat cells. Glucose then reaches the body's cells and the blood's sugar content sinks. Additionally, the insulin inhibits the production of new sugar in the liver. Type 2 diabetics are able to produce sufficient volumes of insulin; however, their cells are resistant to it - and the hormone is unable to fulfil its task. If untreated, this disease damages the blood vessels due to the raised blood sugar levels, which can lead to a heart attack or stroke.
The molecular processes in the body's cells responsible for the connection between body weight and diabetes are largely unknown. However, in all tissues that respond to insulin, Micro-RNAs can be found. The Cologne-based scientists working with Jens Brüning, Director at the Max Planck Institute for Neurological Research and scientific coordinator of the Cologne Cluster of Excellence in Cellular Stress Responses in Aging-associated Diseases at the University of Cologne assume, therefore, that micro-RNAs may also play a role in type 2 diabetes. These short ribonucleic acid molecules can regulate the activity of genes and thus control protein production.
The research group in Cologne has now discovered a new mechanism that leads to insulin resistance of the cells. Accordingly, obese mice form excess miRNA-143 in their livers. This RNA molecule silences genes that are responsible for the activation of the enzyme AKT and therefore inhibits insulin from activating AKT. "AKT is important for glucose transport in the cell and for the inhibition of glucose synthesis in the liver. When the enzyme is inhibited, insulin fails to take effect and the blood sugar remains elevated," explains Jens Brüning.
For their research study, the researchers compared normal weight mice with obese mice with type 2 diabetes. They discovered that the diseased animals produce more than twice as much miRNA-143 in their livers than the normal ones. Moreover, the researchers found only a low concentration of the protein ORP8 in the obese mice which formed large quantities of miRNA-143. ORP8 stimulates insulin to activate AKT and therefore reduces the sugar content of the blood. If ORP8 is lacking, insulin is unable to take effect and the AKT remains inactive.
The researchers do not yet know why obese mice form more miRNA-143 than their normal weight counterparts. "If we succeed in explaining the signalling paths 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 future research plans.
Dr. Cornelia Weigelt | EurekAlert!
A Map of the Cell’s Power Station
18.08.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau
On the way to developing a new active ingredient against chronic infections
18.08.2017 | Deutsches Zentrum für Infektionsforschung
Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.
As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
16.08.2017 | Event News
04.08.2017 | Event News
26.07.2017 | Event News
18.08.2017 | Life Sciences
18.08.2017 | Physics and Astronomy
18.08.2017 | Materials Sciences