# Fluorescent Indicators for Imaging Synaptic Zinc in Cortical Sound Processing

> **NIH NIH R01** · UNIVERSITY OF VIRGINIA · 2024 · $655,437

## Abstract

Abstract
Although the importance of synaptic Zn2+, as an emerging neuromodulator throughout the brain, has been widely
appreciated, the dynamics of synaptic Zn2+ release in response to naturally occurring stimuli remains largely
elusive. Genetically encoded Zn2+ indicators (GEZIs) derived from fluorescent proteins are popular tools for
imaging Zn2+ in the cytosol and intracellular organelles. However, fluorescence imaging of Zn2+ secretion in the
brain in live animals has not yet been achieved due to the limitations of current GEZIs (e.g., insufficient
extracellular membrane localization, mismatching affinity, and/or inadequate dynamic range and photostability).
This interdisciplinary multi-PI 4-year R01 project, led by Dr. Huiwang Ai with expertise in genetically encoded
indicators and fluorescence imaging and Dr. Thanos Tzounopoulos with expertise in studying the role of Zn2+ in
auditory processing, aims to (1) develop a new generation of GEZIs to address the hurdles for imaging secreted
Zn2+ in the brain in vivo, and (2) integrate the new GEZIs with our innovative ZnT3 cKO mice, which, for the first
time, allow for Cre-dependent expression of exogenous genes in ZnT3-expressing neurons and Dre-dependent
region- and cell type-specific conditional ZnT3 gene knockout, to identify the cell- and circuit-specificity of Zn2+
dynamics that shape cortical sound processing.
The project will lead to a novel capability of imaging synaptically released Zn2+ in the brain in awake behaving
animals. Our innovative strategy to optimize the exoplasmic location of GEZIs may be generalized to enhance
other genetically encoded indicators. Furthermore, because synaptic Zn2+ is a potent modulator throughout the
cortex, our findings on Zn2+ dynamics in the primary auditory cortex (A1) during sound processing will improve
the understanding of the roles of synaptic Zn2+ in cortical information processing beyond sensory cortices. We
expect our studies to catalyze an extensive array of studies on Zn2+-related neurobiology and neurological
diseases.

## Key facts

- **NIH application ID:** 10888267
- **Project number:** 5R01EB033172-03
- **Recipient organization:** UNIVERSITY OF VIRGINIA
- **Principal Investigator:** Huiwang Ai
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $655,437
- **Award type:** 5
- **Project period:** 2022-09-30 → 2026-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10888267

## Citation

> US National Institutes of Health, RePORTER application 10888267, Fluorescent Indicators for Imaging Synaptic Zinc in Cortical Sound Processing (5R01EB033172-03). Retrieved via AI Analytics 2026-05-28 from https://api.ai-analytics.org/grant/nih/10888267. Licensed CC0.

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