Interorgan communication through peripherally derived peptide hormones in Drosophila

Abstract

In multicellular organisms, endocrine factors such as hormones and cytokines regulate development and homoeostasis through communication between different organs. For understanding such interorgan communications through endocrine factors, the fruit fly Drosophila melanogaster serves as an excellent model system due to conservation of essential endocrine systems between flies and mammals and availability of powerful genetic tools. In Drosophila and other insects, functions of neuropeptides or peptide hormones from the central nervous system have been extensively studied. However, a series of recent studies conducted in Drosophila revealed that peptide hormones derived from peripheral tissues also play critical roles in regulating multiple biological processes, including growth, metabolism, reproduction, and behaviour. Here, we summarise recent advances in understanding target organs/tissues and functions of peripherally derived peptide hormones in Drosophila and describe how these hormones contribute to various biological events through interorgan communications.

A gut-derived hormone suppresses sugar appetite and regulates food choice in Drosophila

“…These signals presumably convey different aspects of nutritional status and may act with different dynamics to regulate AKH production and/or release, or even in a redundant manner to regulate AKH signalling. Likewise, many signals released from the fat body convey similar and seemingly redundant nutritional information to the IPCs 2 , 53 , 54 .…”

Endocrine cybernetics: neuropeptides as molecular switches in behavioural decisions

“…The intestine is an ideal site for monitoring the nutritional state of an organism and mediating hormonal signals to the brain to adjust physiology and nutrient-dependent behaviour in order to maintain metabolic homeostasis. In Drosophila and other insects, such signals are primarily constituted by peptide hormones released from nutrient-sensing EECs of the intestine (figure 9) [32,221,[247][248][249][250]. The Drosophila EECs and other gut cells produce at least 12 different peptides [32,40,41,245,250] (electronic supplementary material, figure S5).…”

“…These modulatory circuits or pathways are not necessarily hardwired, but rather they commonly depend on paracrine signalling or volume transmission, which is based on non-synaptic release of an amine or neuropeptide over a shorter or longer distance within the CNS [6,18,22,[24][25][26]. Some of the modulatory signalling is even hormonal, via the circulation, representing interorgan communication (see for instance [18,[27][28][29][30][31][32]).…”

“…Additionally, circulating peptide hormones may also act as organizers of behaviour and physiology at a high level in the hierarchy (see [18,27,29,30,39]). Some of these hormones are released from enteroendocrine cells (EECs) of the intestine [32,[40][41][42][43]. Many of the EECs are nutrient-sensing and thus serve to signal the nutritional state of the organism to the brain, thereby modulating relevant nutrient/ energy-dependent behaviours as well as regulating metabolic homeostasis [39,[43][44][45].…”

The incidence of candidate binding sites for β-arrestin in Drosophila neuropeptide GPCRs

“…However, this conclusion is speculative as such mechanisms are largely unknown in the fly. A sophisticated genetic model system like Drosophila, coupled with the rich history of neuroendocrine and neuropeptide physiology in insects [65][66][67], provides a novel complimentary path forward, for a better understanding of β-arrestin regulatory biology. Given the prominent role of GPCRs in normal signaling, and as targets for a large fraction of modern therapeutics [68,69], the significance of such model studies could be substantial.…”