Insulin resistance is characterized by the lack of tissue response to insulin and is counteracted by a greater production of insulin by the pancreas. When the pancreas does not have the capacity to produce the amount of insulin required for tissues to receive glucose, glucose in blood increases to pathological levels and the individual goes from being insulin-resistant to suffering type 2 diabetes.
Although it is unclear what makes people develop insulin resistance, several studies report that resistant subjects show functional alterations in mitochondria. These intracellular organelles are responsible for transforming glucose into energy that the cell will then use to perform several functions. A study performed by the researcher Marc Liesa, a member of Antoni Zorzano’s lab at the Institute for Research in Biomedicine (IRB Barcelona), describes a new control pathway of a gene responsible for mitochrondrial fusion, a process that contributes to the correct function of these organelles. This pathway could therefore be a key component in the development of insulin resistance. The results of this study have been published in the scientific journal PloS One.
Diabetes: a complex genetic map
Previous studies demonstrated that people resistant to insulin have altered mitochondrial capacity to “generate” energy through a process called oxidative phosphorylation. In a study performed in 2003, two possible main actors were identified, the genes PGC1-beta and PGC1-alpha. These two genes are responsible for regulating the whole cascade of genes and proteins that allow mitochondria to produce energy by means of oxidative phosphorylation. Now, for the first time, a study has shown that another gene, called Mitofusin 2 (Mfn2), which is decreased in diabetic patients, is also controlled by PGC1-beta. This information is highly relevant because until now it was considered that PGC1-beta controlled the production of energy only by regulating the expression of mitochondrial genes responsible for oxidative phosphorylation. “We have discovered what the cell does to regulate this mitochondrial fusion gene and we explain why this gene is decreased in diabetes, as it is regulated by PGC1-beta, which in turn is affected by this disease. However, although this evidence allows us to propose interesting hypotheses as to the role of Mfn2, its exact role remains unknown”, explains the first author of the study, Marc Liesa.
Key or secondary role in diabetes?
One of the hypotheses is that mitochondrial fusion is crucial for the correct function of these organelles and when the gene that regulates this fusion is decreased, the function of mitochondria is also impaired. But where is Mfn2 situated in the genetic map of diabetes? Is the decrease in mitochondrial fusion related directly to the appearance of insulin resistance? The researchers have obtained the first data that support the notion that Mfn2 plays a key role.
In 2005, in experiments in vitro using rat skeletal muscle cells, the scientists removed the expression of only the Mfn2 gene without touching PGC1-beta, and confirmed that the decrease in mitochondrial fusion affected the capacity to generate energy, “regardless of whether PGC1-beta is functioning correctly”, stresses the head of the group, Antonio Zorzano. “What we are proposing is that the alteration in the fusion alters mitochondrial activity. Observation that the removal of only Mfn2 produces insulin resistance in later experiments in a simple living model – not only in individual cells - , would imply that modulation of this gene contributes to this pathology, thereby making Mfn2 a therapeutic target of interest”, concludes Zorzano.
Type 2 diabetes currently affects 6.5% of the populated aged between 30 and 65 in Spain and recent years have witnessed an increasing incidence of this disease among adolescents and children.
Sònia Armengou | alfa
Water forms 'spine of hydration' around DNA, group finds
26.05.2017 | Cornell University
How herpesviruses win the footrace against the immune system
26.05.2017 | Helmholtz-Zentrum für Infektionsforschung
Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.
Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....
Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.
The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....
An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.
We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...
Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.
Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...
An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...
24.05.2017 | Event News
23.05.2017 | Event News
22.05.2017 | Event News
26.05.2017 | Life Sciences
26.05.2017 | Life Sciences
26.05.2017 | Physics and Astronomy