Systemic Coordination of Invertebrate Homeostasis

In order to achieve a coordinated physiological response to a given stimulus, an organism must be able to sense alterations of their microenvironment and communicate these alterations to remaining tissues and organs far apart. Metazoans have developed an intricate system for coordinating physiological responses among several organs, through the production of molecular mediators comprising a diversity of chemical classes. Among invertebrates, lipid hormones like the insect juvenile hormone and ecdysone have long been known to regulate a wide range of life-history traits. However, knowledge of the complexity of regulatory mechanisms is scant. Additionally, the fact that the microbiota behave as an additional system regulating invertebrate physiology has brought an extra layer of complexity to the field. Fortunately, a new array of studies has been shedding new light on the mechanisms of sensing, action and transport of molecules involved in the multi-systemic coordination of physiological features.

The advance of large scale omics and the refinement of transgenic tools and other reverse genetic methodologies has allowed a deeper understanding of multisystemic regulation of invertebrate homeostasis. For example, Drosophila amino acid sensing following gut uptake was recently shown to drive the TOR-regulated production of the peptide “Stunted” by fat body cells. “Stunted” was shown to drive the brain cell production of insulin, which coordinates a plethora of physiological pathways. Other recent works have detailed the mechanisms used by insulin to modulate energy expenditure during immune responses. Regulation of these signaling and metabolic pathways are also determinants of the ability of pathogens to multiply inside invertebrates. For example, two independent publications have collectively evidenced the importance of mosquito lipid homeostasis for Plasmodium development. The mosquito endocrine system was shown to be an important co-regulator of egg and parasite growth and the proper circulation of a lipid transporter was shown to be essential for parasite viability.

This Research Topic will focus on the mechanisms of sensing, action and transport involved in the multi-systemic coordination of physiological features. We anticipate that future work will continue to use molecular and cellular biology tools to provide exciting new evidence of this coordination in invertebrates. We expect contributions to this topic, including work on:

• The role of nutrient-sensing pathways in defining metabolic and physiological status;
• The coordination of metabolic status among multiple systems through the production and sensing of putative effectors;
• Metabolic regulation of energy expenditure, nutrient storage, and fecundity;
• Mechanisms and pathways of regulation of homeostasis following environmental cues;
• Coordination of transport and diffusion of metabolites and regulators through circulatory systems; • Mechanisms of homeostasis involved in metabolic regulation of immunity, vector competence and parasite development;
• The role of multiple systems and organs in the coordination of immune responses;
• The role of microbiota in the regulation of host metabolism and immunity, and effects of nutrition, metabolism and immune status on microbiota levels and diversity;
• Effects of infection on the arthropod metabolome.
• Systemic regulation of reproductive fitness and egg or yolk production.