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Teams of CSGA

The team's work is dedicated to basic research to unravel the genetic, molecular and cellular mechanisms at the origin of chemoperception using one of the most powerful models in neurogenetics, Drosophila melanogaster. We study various aspects of olfactory and gustatory perception and how this information is processed and integrated in the brain. We are trying to understand the impact of molecules from food on behavior: odors (mainly short fatty acids), bacterial compounds (peptidoglycan), and sugars (glucose). Concerning the central processing of this chemosensory perception, we focus on a family of amino acid transporters (SLC7) and on the interactions between glia and neurons in the primary (antennal lobe) and secondary (mushroom bodies) centers. We also seek to understand how to replace the use of insecticides, which are toxic to the ecosystem, biodiversity and human health, with food odors to protect fruit crops from insect pests. In this context, we are interested in plant-microorganism-insect communication, mainly targeting Drosophila suzukii.

To accomplish our research goals, we use a wide range of techniques from molecular biology, molecular genetics, evolutionary genetics, biochemistry, cell biology, cell and tissue culture, immunohistology, in vivocalcium imaging, neurobiology, neurophysiology, optogenetics, developmental biology, behavioral analysis. We design and develop our own specific tools.

Description of TPI team

Our team aims to understand the development and the determinants of food preferences and eating behaviour across the life span in relation with population and planetary health.

Eye & Nutrition

One of our primary interest is to understand how flies interact with their environment and how taste is detected, integrated and translated into appropriate feeding behaviour. Here we aim at understanding the neural network involved in taste detection and  feeding control by the use of the STROBE, a previously automated optogenetic device conceived in the GORDON Lab at the University of British Columbia (Musso et al., 2019).

Caloric post-ingestive integration

Taste sensing is not the only aspect of feeding regulation. Indeed, during a meal course, nutrients ingested are detected in the guts and in the brain by specific sensors which then, modulate the feeding sequence. During his postdoctorate in the the GORDON Lab, Pierre-Yves uncovered a new mechanism investigating how the satiating effect of glucose regulate the feeding-promoting effect of fructose (Musso et al., 2021). Surprisingly, the post-ingestive detection of nutrients is still poorly understood. Here we aim at identifying and characterizing new sensor detecting nutrients during food ingestion and integrate them in the complex frame of feeding regulation.

 

Sweet taste and caloric post-ingestive integration

Taste and post-ingestive nutrient detection are two mechanisms evaluating food quality. In fact, taste acts as a predictor of the incoming nutrient. As an example, sweet taste predicts energy. But, a growing number of food available displays an uncoupling between sweet taste and energy by the use of Non or Low-Caloric Sweeteners (NCS or LCS). In a previous study, Pierre-Yves demonstrated that flies devaluate the value associated to sweet taste following ingestion of non-caloric sugar (Musso et al., 2017). However, how taste devaluation impacts feeding behaviour as well as metabolism remains unclear. Here, we plan to tackle this question as well as identifying the neural substrate leading to this phenomenon.

 

Our research activities are subdivided into 3 main areas: 1) the molecular mechanisms underlying chemosensory perception of sapid molecules (taste receptors : umami, sweet and bitter taste), the perception of some sweet proteins (brazein and monellin) or taste-modifying proteins (miraculin, gurmarin); 2) the molecular mechanisms that enable peripheral (oral) perception of sugars/sweeteners and their central (hypothalamic) detection, depending on taste receptors or not, as well as  their effects on the control of food consumption, food choice/preference and metabolism regulation in physiological and pathological (diabetes, obesity) states in mice ; 3) the structure/activity relationships on sweet-taste receptor TAS1R2/TAS1R3 of the natural glycosylated secondary metabolites, such as saponins, after extraction and purification by various chromatographic methods then spectral analysis (2D NMR).

Our work, that ultimately aims to better understand gustatory perception and its importance in human physiology, combines a variety of approaches, from molecular and cellular biology, biochemistry, pharmacognosy and structural biology to integrated studies of the central nervous system and the whole organism, using both in vitro and rodent models.

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