These brain cells that could help fight obesity

Although their role is less known than that of neurons. Moreover, astrocytes are cells essential to the functioning of the brain. Meanwhile, A new study. Moreover. Therefore, in mice, published in the journal Nature communications reveals the role of the astrocytes of the striatum, a structure of the reward circuit, in the context of the obesity induced by a diet enriched with fat and sugars. In addition, These cells could represent an interesting target for the treatment of metabolic diseases.

The brain is made up of billions of neurons. Furthermore, These are excitable cells. Therefore. Consequently, that is to say that they can generate action potentials and transmit information to other neurons in the form of electric current. However. Furthermore. However, neurons constitute only half of the brain cells, the other half these brain cells could help new being made up of glial cells, among which are the astrocytes. Similarly. Nevertheless, these brain cells could help The latter are involved in many brain pathologies such as neurodegenerative diseases (Alzheimer or Parkinson disease), psychiatric disorders or epilepsy.

Unlike neurons, astrocytes cannot generate electric currents, but have variations in their intracellular calcium concentration. Meanwhile, Intracellular calcium is involved in many processes related to the functioning of cells. However, would have an essential role for the physiology of astrocytes. Nevertheless. Similarly, The fact that astrocytes are silent for conventional methods of recording brain activity such as electroencephalogram (ECG) made their study much slower. Therefore, difficult. Consequently. Therefore. Consequently, their role has been largely underestimated and we are still far from having elucidated the way in which they communicate with neurons. Nevertheless,

It is with the development of imaging tools targeting specific cellular actors that their role in brain processes. Furthermore, these brain cells could help new can finally be elucidated. Moreover. Furthermore, The results we have obtained make it possible to highlight several characteristics of the astrocyte these brain cells could help activity in the context of the obesity induced by the food enriched in fat. Meanwhile, sugar.

These brain cells could help new

When the body no longer balances the energy balance – These brain cells could help new

These brain cells could help

Obesity. is a major public health problem. affecting 17 % of the French population. increasing the relative risk of a set of pathologies: for example, heart disease, hypertension, type 2 diabetes, liver disease and certain forms of cancer. This pathology is complex. implies different factors whose contribution to the development of obesity varies considerably from one individual to another: these factors are genetic. environmental (such as stress or quality of sleep) or linked to eating habits. A diet enriched with fats and sugars is definitely an identified culprit.

Our body these brain cells could help new maintains a state of equilibrium called homeostasis. thanks to a precise regulation mechanism which balances nutritional intake and energy expenditure. This balance of the energy balance is carried out thanks to these brain cells could help well identified brain circuits. notably involving the hypothalamus. However. another powerful engine of food is the hedonic aspect of food. that is to say the pleasure that we find in consuming appetizing foods, beyond the energy needs of the body. This motivation to eat for pleasure is based in particular on the release of dopamine at the level of. a brain region called striatum.

Obesity induced by food has been shown to be associated with alterations in the transmission of dopamine. with food/compulsive food disorders as well as an impairment of cognitive flexibility. that is to say the ability to easily adapt to new situations.

Astrocytes. protective cells of neurons

If the involvement of these brain cells could help new neurons (which release. respond to dopamine) has been studied a lot in the context of these physiological and pathophysiological processes, the role of astrocytes has long been neglected.

The excess of nutrients promotes inflammatory these brain cells could help mechanisms in the brain which are accompanied. by the release of substances likely to modify the functioning of neurons. astrocytes. However. astrocytes occupy a strategic place in the brain. at the interface between blood vessels and neurons, these pivot cells would make it possible to control the neuronal information as well as energy intake. As a nutritional excess in circulation. they could constitute a first rampart which would protect the neurons of the alterations induced by the elements circulating. in the blood.

In our work. carried out in mice, we show first of all that fatty regimes affect the structure and function of astrocytes of the striatum.

We had already characterized such modifications in the hypothalamus. the region involved in the initiation of food intake. which is in close contact with the blood compartment, but they were very little characterized in the striatum. We show. on the one hand. a responsiveness of astrocytes, which is expressed by morphological modifications, and, on the other hand, changes in the dynamics of calcium flows, likely to alter their communication with the neurons of the structure.

An impact on cognitive flexibility. energy metabolism

This observation made. we decided to directly handle these brain cells could help new the astrocytes by an approach allowing to force a signaling cascade in the cells by specifically inserting in astrocytes a synthetic receiver playing the role of switch. This these brain cells could help approach allows in particular to induce a wave of calcium (a second key. messenger at the intracellular level). in order to observe the consequences.

What happens if we artificially increase the quantity of calcium and “activate” astrocytes? Does this have an impact on neuronal activity and the behavior of mice?

The activation of this molecular switch. the influx of coherent calcium in the population of targeted astrocytes actually had the consequence of modifying the kinetics. Additionally, the response of the neighboring neurons thus demonstrating, for the first time, that the manipulation of astrocytes could interfere with the neural networks.

We applied this technique by comparing nourished mice with a standard diet with mice made obese by these brain cells could help new a regime. enriched with fats. sugars. Enriched mice under regime present cognitive defects which are expressed by a difficulty in adapting to a new situation. In our case. the mice had to learn these brain cells could help that a reward was located in the left arm of a labyrinth. then we examined how they adapted if we changed the rewarded arm.

In this context. the mice fed with an enriched diet had trouble adapting. but the forced activation of astrocytes of the dorsal striatum allowed animals to easily relearn the task, and this, in the absence of weight loss. Additionally, The manipulation of astrocytes of the striatum thus made it possible to correct the cognitive alteration induced by the. rich diet.

If the striatum is well known for its role in cognitive. motivational processes, this brain structure is not traditionally associated with the regulation of bodily metabolism. Our study these brain cells could help new brings an additional element in this direction. Indeed. we show that manipulation in vain Astrocytes in the striatum exercises control over the animal’s energy metabolism by particularly affecting the choice of metabolic substrates (lipids. sugars) used by these brain cells could help the mouse to ensure its metabolism. After activation of astrocytes, they use more lipids.

This work reveals a new role for astrocytes in the reward circuits. They participate in the control of cognitive functions. our results illustrate for the first time their ability to restore a cognitive function in an obesogenic context. On the other hand. this work establishes a direct link between the astrocytes of the striatum. the control of the overall energy metabolism of the animal.

A promising approach would be to develop therapeutic strategies specifically targeting astrocytes. rather than neurons, within the reward system, in the treatment of obesity and, more broadly, metabolic pathologies.

these brain cells could help new