AUTHOR=Sajadi Farwa , Paluzzi Jean-Paul V. 

TITLE=Molecular characterization, localization, and physiological roles of ITP and ITP-L in the mosquito, Aedes aegypti

JOURNAL=Frontiers in Insect Science

VOLUME=4

YEAR=2024

URL=https://www.frontiersin.org/journals/insect-science/articles/10.3389/finsc.2024.1374325

DOI=10.3389/finsc.2024.1374325

ISSN=2673-8600

ABSTRACT=<p>The insect ion transport peptide (ITP) and its alternatively spliced variant, ITP-like peptide (ITP-L), belong to the crustacean hyperglycemic hormone family of peptides and are widely conserved among insect species. While limited, studies have characterized the ITP/ITP-L signaling system within insects, and putative functions including regulation of ion and fluid transport, ovarian maturation, and thirst/excretion have been proposed. Herein, we aimed to molecularly investigate <italic>Itp</italic> and <italic>Itp-l</italic> expression profiles in the mosquito, <italic>Aedes aegypti</italic>, examine peptide immunolocalization and distribution within the adult central nervous system, and elucidate physiological roles for these neuropeptides. Transcript expression profiles of both <italic>AedaeItp</italic> and <italic>AedaeItp-l</italic> revealed distinct enrichment patterns in adults, with <italic>AedaeItp</italic> expressed in the brain and <italic>AedaeItp-l</italic> expression predominantly within the abdominal ganglia. Immunohistochemical analysis within the central nervous system revealed expression of <italic>Aedae</italic>ITP peptide in a number of cells in the brain and in the terminal ganglion. Comparatively, <italic>Aedae</italic>ITP-L peptide was localized solely within the pre-terminal abdominal ganglia of the central nervous system. Interestingly, prolonged desiccation stress caused upregulation of <italic>AedaeItp</italic> and <italic>AedaeItp-l</italic> levels in adult mosquitoes, suggesting possible functional roles in water conservation and feeding-related activities. RNAi-mediated knockdown of <italic>AedaeItp</italic> caused an increase in urine excretion, while knockdown of both <italic>AedaeItp</italic> and <italic>AedaeItp-l</italic> reduced blood feeding and egg-laying in females as well as hindered egg viability, suggesting roles in reproductive physiology and behavior. Altogether, this study identifies <italic>Aedae</italic>ITP and <italic>Aedae</italic>ITP-L as key pleiotropic hormones, regulating various critical physiological processes in the disease vector, <italic>A. aegypti</italic>.</p>