A nutrient-sensitive enterokine coordinates developmental plasticity through inter-organ signaling

Area of Science:

• Endocrinology
• Developmental Biology
• Nutritional Physiology

Background:

• Animal survival hinges on developmental plasticity, the ability to adjust growth rates based on nutrient availability.
• Endocrine signaling plays a crucial role in mediating these adaptive responses to environmental fluctuations.

Purpose of the Study:

• To elucidate the endocrine mechanisms governing developmental plasticity in Drosophila larvae under amino acid restriction.
• To identify key signaling molecules and pathways involved in nutrient sensing and growth regulation.

Main Methods:

• Identification and characterization of the peptide hormone Limostatin.
• Analysis of Limostatin's production site (larval midgut enteroendocrine cells) and its systemic effects.
• Investigation of the inter-organ communication involving the fat body and brain neuroendocrine cells.
• Examination of Limostatin's feedback control loop on insulin-like peptide (dIlp2) expression and release.

Main Results:

• Limostatin, an enterokine from midgut cells, inhibits dIlp2, a key peptide for developmental progression.
• Reduced amino acid levels trigger Limostatin secretion via a fat body-brain neuroendocrine relay.
• Limostatin forms a feedback loop, slowing development in response to nutrient scarcity.
• This gut-brain axis mechanism enhances larval survival under nutritional stress.

Conclusions:

• The larval gut functions as a nutrient-sensitive endocrine organ regulating developmental plasticity.
• Limostatin is a critical mediator of developmental pace control in response to nutrient availability.
• Enterokines regulating insulin/IGF signaling represent a conserved strategy for developmental plasticity across species.