A post-ingestive amino acid sensor promotes food consumption in Drosophila

Abstract

Adequate protein intake is crucial for the survival and well-being of animals. How animals assess prospective protein sources and ensure dietary amino acid intake plays a critical role in protein homeostasis. By using a quantitative feeding assay, we show that three amino acids, L-glutamate (L-Glu), L-alanine (L-Ala) and L-aspartate (L-Asp), but not their D-enantiomers or the other 17 natural L-amino acids combined, rapidly promote food consumption in the fruit fly Drosophila melanogaster. This feeding-promoting effect of dietary amino acids is independent of mating experience and internal nutritional status. In vivo and ex vivo calcium imagings show that six brain neurons expressing diuretic hormone 44 (DH44) can be rapidly and directly activated by these amino acids, suggesting that these neurons are an amino acid sensor. Genetic inactivation of DH44+ neurons abolishes the increase in food consumption induced by dietary amino acids, whereas genetic activation of these neurons is sufficient to promote feeding, suggesting that DH44+ neurons mediate the effect of dietary amino acids to promote food consumption. Single-cell transcriptome analysis and immunostaining reveal that a putative amino acid transporter, CG13248, is enriched in DH44+ neurons. Knocking down CG13248 expression in DH44+ neurons blocks the increase in food consumption and eliminates calcium responses induced by dietary amino acids. Therefore, these data identify DH44+ neuron as a key sensor to detect amino acids and to enhance food intake via a putative transporter CG13248. These results shed critical light on the regulation of protein homeostasis at organismal levels by the nervous system.

CCAP regulates feeding behavior via the NPF pathway inDrosophilaadults

“…In order to maintain homeostasis, the brain must process extrinsic and intrinsic information. In Drosophila, different peptides have been shown to regulate these signals, such as diuretic hormone 44 (Dh44) (39,40), corazonin (Crz) (41), allatostatin A (AstA) (42,43), and SIFamide (SIFa) (44). Furthermore, similar to mammals, insulin-like peptides and a glucagon-like hormone (AKH) are also involved in regulating feeding behavior (45,46).…”

Transcriptome analysis reveals nutrition‐ and age‐related patterns of gene expression in the fat body of pre‐overwintering bumble bee queens

“…The peptide is produced in both the midgut (Veenstra, Agricola, & Sellami, ) and brain (Hergarden, Tayler, & Anderson, ), and regulates production of both adipokinetic hormone (AKH) and insulin‐like peptides (DILPs) in Drosophila (Deveci, Martin, Leopold, & Romero, ; Hentze, Carlsson, Kondo, Nässel, & Rewitz, ). DH44 is known as a neuropeptide that is essential for regulating feeding behaviour and food consumption in a nutrient‐dependent manner in Drosophila (Dus et al, ; Yang et al, ). These receptors were down‐regulated in queens given a more sucrose‐rich diet in our study.…”

Growth regulation by amino acid transporters in Drosophila larvae

“…In Drosophila adults, nutrients and amino acids are also crucial since flies need food resources to regulate their life cycle, to survive, to have social interactions and to reproduce. In adults, the essential amino acid threonine promotes sleep via GABA neurons in the brain and three other amino acids ( l -Glutamate, l -Alanine and l -Aspartate) are able to directly stimulate DH44 + brain neurons to increase in food consumption via a putative amino acid transporter, CG13248 [ 53 , 54 ]. In adult females, nutrients play also an important role in germline stem cells development.…”