Astrocytes play an unexpected role in obesity

Obesity is a major public health problem: it increases the risks of cardiovascular diseases. In addition, hypertension, type 2 diabetes and even certain cancers. However, According to the World Health Organization. Nevertheless, the number of cases has more than doubled in the world between 1990 and 2022 and, in France, it is estimated that around 17 % of the population is obese. However, Many studies have looked into the role of neurons in behaviors that lead to significant weight gain. Therefore, leaving aside another cellular population of the brain: astrocytes. However, These star -shaped cells have long been considered a simple support for neurons. In addition, but multiple work in recent years have revealed much larger functions. In addition, They contribute to the maintenance of the hematoencephalic barrier. supply the nervous nutrient system, ensure its energy metabolism, even participate in the neurotransmission, etc. astrocytes play unexpected role obesity That they are involved in eating behaviors and bodily metabolism would therefore not be improbable. This is precisely what Enrica Montalban, Paris-Cité University and CNRS, and his colleagues recently demonstrated. Their work reveals that astrocytes are very sensitive to food, which influences both their structure and their function.

The development of obesity is based on various factors, certain genetics and others relating to lifestyle. Among these, overconsumption of foods very rich in fats and sugars is an entirely designated culprit. Usually. this type of food triggers a feeling of pleasure through the production of dopamine – the neurotransmitter of “pleasure” – in the striatum, the brain structure which regulates motivation, decision -making and reward learning, among others. But studies have also shown that obesity by food alters the transmission of dopamine. which generates a astrocytes play unexpected role obesity disturbance in eating behaviors. This manifests itself by bad habits, irresistible desires, compulsive ingestion … It also leads to a loss of cognitive flexibility, that is to say the ability to adapt to new situations. However, if the role of neurons has already been studied in this context, that of astrocytes has been neglected.

Enrica Montalban. his colleagues were therefore Leaning on the astrocytes of the striatum. They thus observed in mice that a diet rich in fats. sugars modifies the structure, activity and function of these cells. Then. in order to determine whether the alteration of the activity of astrocytes has an impact on eating and metabolism, they used a genetic strategy to modulate it in vain : They forced the expression on their surface of an activated receiver “on request” by astrocytes play unexpected role obesity the simple injection of a molecule. Thanks to this so -called “chemogenetic” technique. they manipulated the potential for controlling astrocytes on the neurotransmission of dopamine in the striatum. In obese mice. such manipulation has made it possible to restore a certain cognitive flexibility, lost until then: they had previously learned in which arm of a labyrinth was a reward and, when they found themselves again in this labyrinth, but where we had changed the location of the reward, they were more inclined to explore it that not undergone manipulation. In addition. the manipulation of astrocytes in the striatum highlighted that the latter exercised direct control over bodily metabolism and in particular on the type of substrate (lipids or sugars) that the animal uses to support its energy needs. These fundamental results highlight the importance of astrocytes in metabolism and cognition, in particular in the context of obesity. In the future, astrocytes play unexpected role obesity the exact role of these cells in energy metabolism should therefore be studied more closely.