Biology subjects

Croset, V.

Publications and source records attributed to Croset, V..

5 recordsLinked to original sources

bioRxiv2026

Intracellular amino acid scarcity sensing tunes protein hunger

Protein is a key macronutrient that strongly governs food intake. Following dietary protein scarcity, animals display compensatory preference for amino acid-rich food, yet how the brain detects and encodes protein hunger remains unclear. To address this question, we used Drosophila melanogaster to investigate the function of peptidergic neurons, a major neuromodulatory cell population that includes key regulators of feeding behaviour and protein homeostasis. We present a high-resolution transcriptional atlas obtained by RNA sequencing of single peptidergic nuclei isolated from the brains of sated and amino acid deprived flies. Consistent with a resource-sparing response, differential expression analysis revealed widespread transcriptional downregulation in the amino acid deprived state. A screen of differently expressed candidates identified Lsp2, a gene encoding an amino acid storage protein, as a regulator of protein intake. Knock down and overexpression experiments demonstrate that Lsp2 levels act as a gauge in a specific population of peptidergic neurons expressing Myoinhibiting peptide precursor (Mip) to modulate protein appetite. We further show that compensatory protein feeding following amino acid deprivation depends on maintaining Mip+ neuron activity within an appropriate range. Our findings reveal that peptidergic neurons can directly sense intracellular protein deficiency and use this information to guide protein intake. By linking amino acid storage to the neuronal control of feeding, this work establishes a foundation for understanding how protein needs are encoded in the brain.

neuroscience↗

bioRxiv2022

Gliotransmission of D-serine promotes thirst-directed behaviors in Drosophila

Thirst emerges from a range of cellular changes that ultimately motivate an animal to consume water. Although thirst-responsive neuronal signals have been reported, the full complement of brain responses is unclear. Here we identify molecular and cellular adaptations in the brain using single-cell sequencing of water deprived Drosophila. Water deficiency primarily altered the glial transcriptome. Screening the regulated genes revealed astrocytic expression of the astray-encoded phosphoserine phosphatase to bi-directionally regulate water consumption. Astray synthesizes the gliotransmitter D-serine and vesicular release from astrocytes is required for drinking. Moreover, dietary D-serine rescues aay-dependent drinking deficits while facilitating water consumption and expression of water-seeking memory. D-serine action requires binding to neuronal NMDA-type glutamate receptors. Fly astrocytes contribute processes to tripartite synapses and the proportion of astrocytes that are themselves activated by glutamate increases with water deprivation. We propose that thirst elevates astrocytic D-serine release, which awakens quiescent glutamatergic circuits to enhance water procurement.

neuroscience↗

bioRxiv2019

A single-cell transcriptomic atlas of the adult Drosophila ventral nerve cord

The Drosophila ventral nerve cord (VNC) receives and processes descending signals from the brain to produce a variety of coordinated locomotor outputs. It also integrates sensory information from the periphery and sends ascending signals to the brain. We used single-cell transcriptomics to generate an unbiased classification of cellular diversity in the VNC of five-day old adult flies. We produced an atlas of 26,000 high-quality cells, representing more than 100 transcriptionally distinct cell types. The predominant gene signatures defining neuronal cell types reflect shared developmental histories based on the neuroblast from which cells were derived, as well as their birth order. Cells could also be assigned to specific neuromeres using adult Hox gene expression. This single-cell transcriptional atlas of the adult fly VNC will be a valuable resource for future studies of neurodevelopment and behavior.

neuroscience↗

bioRxiv2018

An expression atlas of chemosensory ionotropic glutamate receptors identifies a molecular basis of carbonation detection

Taste perception is thought to involve the encoding of appetitive and aversive chemical cues in food through a limited number of sensory pathways. Through expression analysis of the complete repertoire of Drosophila Ionotropic Receptors (IRs), a sensory subfamily of ionotropic glutamate receptors, we reveal that the majority of IRs is expressed in diverse peripheral neuron populations across gustatory organs in both larvae and adults, implying numerous roles in taste-evoked behaviours. We characterise Ir56d, which labels two anatomically-distinct classes of neurons in the proboscis: one represents a subset of sugar- and fatty acid-sensing neurons, while the other responds to carbonated solutions and fatty acids. Mutational analysis shows that IR56d, together with the broadly-expressed co-receptors IR25a and IR76b, is essential for physiological activation by carbonation and fatty acids, but not sucrose. We further demonstrate that carbonation is behaviourally attractive to flies (in an IR56d-dependent manner), but in a distinct way to other appetitive stimuli. Our work provides a valuable toolkit for investigating the taste functions of IRs, defines a molecular basis of carbonation sensing, and illustrates how the gustatory system uses combinatorial expression of sensory receptors in distinct neuron types to coordinate behaviour.

neuroscience↗

bioRxiv2017

Cellular diversity in the Drosophila midbrain revealed by single-cell transcriptomics

To understand the brain, molecular details need to be overlaid onto neural wiring diagrams so that synaptic mode, neuromodulation and critical signaling operations can be considered. Single-cell transcriptomics provide a unique opportunity to collect this information. Here we present an initial analysis of thousands of individual cells from Drosophila midbrain, that were acquired using Drop-Seq. A number of approaches permitted the assignment of transcriptional profiles to several major brain regions and cell-types. Expression of biosynthetic enzymes and reuptake mechanisms allows all the neurons to be typed according to the neurotransmitter or neuromodulator that they produce and presumably release. Some neuropeptides are preferentially co-expressed in neurons using a particular fast-acting transmitter, or monoamine. Neuromodulatory and neurotransmitter receptor subunit expression illustrates the potential of these molecules in generating complexity in neural circuit function. This cell atlas dataset provides an important resource to link molecular operations to brain regions and complex neural processes.

neuroscience↗