# Hormone regulation of olfactory neuron function in the Zika vector Aedes aegypti

> **NIH NIH F30** · WEILL MEDICAL COLL OF CORNELL UNIV · 2021 · $51,036

## Abstract

PROJECT SUMMARY/ABSTRACT
 Aedes aegypti mosquitoes spread arboviruses including Zika, chikungunya, dengue, and yellow fever
by biting and feeding on the blood of multiple human hosts. Understanding the mechanisms by which
mosquitoes are attracted to humans and disrupting this deadly behavior will have profound implications for
public health. Female Ae. aegypti utilize human cues such as carbon dioxide, heat, and odor to efficiently
locate a host. These mosquitoes naturally experience periods when this strong attraction to humans is
suppressed, including following a blood-meal. The mechanisms underlying host-seeking suppression are
unknown. The objective of this proposal is to establish how endogenous signaling pathways regulate
chemosensory circuits necessary for mosquito host-seeking behavior.
 The physiological state of the female mosquito changes significantly after ingestion of a blood-meal,
when she must digest the protein in the blood to develop eggs. The steroid hormone 20-hydroxecdysone (20E)
is critical for the egg-development process, and levels of 20E are upregulated in the hemolymph (insect blood)
shortly after the blood-meal. In preliminary studies, we demonstrated that feeding 20E to non-blood-fed female
mosquitoes robustly inhibited host-seeking drive. To determine if 20E is acting directly in the brain, Ae. aegypti
brains were immunostained with an antibody for an isoform of the 20E receptor, ecdysone receptor isoform A
(EcR-A). These studies showed that EcR-A is found in specific antennal lobe glomeruli. The antennal lobe
receives projections from chemosensory neurons in the antennae, maxillary palps, and proboscis,
chemosensory organs that are critical for the detection of human odor and carbon dioxide. Understanding how
20E and EcR-A function in the antennal lobe and chemosensory tissues offers mechanistic insights into the
pathways involved in host-seeking behavior. In Aim 1 of this proposal we will characterize EcR-A circuitry in Ae.
aegypti brains and investigate 20E-dependent changes in chemosensory neuron activity. In Aim 2 of the
proposal, we will investigate how 20E and EcR-A regulate expression of olfactory receptors and genes
required for chemosensory signaling machinery in the antenna and palps. It is known that the expression of
olfactory receptors changes after the blood-meal, but the transcriptional mechanism for this regulation is
unknown. EcR-A is a nuclear hormone receptor and transcription factor, and 20E-mediated changes in gene
expression of receptors and signaling machinery in chemosensory neurons is one mechanism that can alter
mosquito responses to host cues after a blood-meal. This research training plan will take place in a highly
supportive laboratory environment and will develop skills in genetic manipulation, live imaging, and
bioinformatics. These studies will contribute fundamental insights into olfactory processing in mosquitoes as
well as provide novel targets for vector control.

## Key facts

- **NIH application ID:** 10247565
- **Project number:** 5F30DC017658-04
- **Recipient organization:** WEILL MEDICAL COLL OF CORNELL UNIV
- **Principal Investigator:** Margaret R. Herre
- **Activity code:** F30 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $51,036
- **Award type:** 5
- **Project period:** 2018-09-01 → 2022-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10247565

## Citation

> US National Institutes of Health, RePORTER application 10247565, Hormone regulation of olfactory neuron function in the Zika vector Aedes aegypti (5F30DC017658-04). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10247565. Licensed CC0.

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