Microbiome-Gut-Brain-Axis communication influences metabolic switch in the mosquitoAnopheles culicifacies

Periodic ingestion of a protein-rich blood meal by adult female mosquitoes causes a drastic metabolic change in their innate physiological status, which is referred to as ‘metabolic switch. Although the down-regulation of olfactory factors is key to restrain host-attraction, how the gut ‘metabolic switch’ modulates brain functions, and resilience physiological homeostasis remains unexplored. Here, we demonstrate that the protein-rich diet induces mitochondrial function and energy metabolism, possibly shifting the brain’s engagement to manage organismal homeostasis. A dynamic expression pattern of neuro-signaling and neuro-modulatory genes in both the brain and gut indicates an optimal brain-distant organ communication. Even after decapitation, significant modulation of the neuro-modulator receptor genes as well as quantitative estimation of neurotransmitters (NTs), together confer the gut’s ability to serve as a ‘second brain’. Finally, data on comparative metagenomic analysis and altered NTs dynamics of naïve and aseptic mosquitoes provide the initial evidence that gut-endosymbionts are key modulators for the synthesis of major neuroactive molecules. Conclusively, our data establish a new conceptual understanding of microbiome-gut-brain-axis communication in mosquitoes. Abstract Figure Graphical abstract Highlights Highly proteinaceous blood meal uptake causes gut ‘metabolic switch’ activity in mosquitoes. Gut’s calling shifts the brain’s administrative function from external communication to inter-organ management. ‘Gut’, as a ‘Second brain’ plays a crucial role in the maintenance of physiological homeostasis. Metabolic switch and proliferation of symbiotic bacteria establish microbiome-gut-brain axis communication in mosquitoes.