# Imaging Immunometabolism in live animals during host defense

> **NIH NIH R21** · UNIVERSITY OF WISCONSIN-MADISON · 2021 · $230,676

## Abstract

PROJECT SUMMARY
Advances in macrophage biology have revealed that metabolic pathways play key roles to control their activation
phenotype and effector function during host defense and tissue homeostasis. In vitro studies led to fundamental
insights into immunometabolism, however our understanding of the functional relevance of metabolic changes
in macrophages within native interstitial tissues remains limited. Here, we propose that fluorescence lifetime
imaging microscopy (FLIM) of metabolic coenzymes NAD(P)H and FAD is a powerful imaging-based tool to
probe the temporal and spatial changes in intracellular metabolism in situ in a live organism. Imaging-based
approaches allow for maintaining highly plastic macrophages in their native microenvironment and examine their
intracellular metabolism in physiological and clinically relevant contexts. Zebrafish is an established in vivo model
of immunity and inflammation, with high similarity to the human immune system and genome. Due to the optical
clarity at larval stage it readily combines with most imaging modalities. Clinical treatment and management of
cutaneous wounds caused by thermal injury is difficult, and patients are at high risk to encounter further
complications due to common nosocomial pathogens, such as Pseudomonas aeruginosa. Here, we will employ
FLIM to study the metabolic regulation of activation and function of macrophages responding to Pseudomonas
aeruginosa-infected burn wounds, using larval zebrafish as our in vivo system. In Aim I, we will develop tools to
assess the spatial and temporal changes in macrophage metabolism in situ in a live organism. In Aim II, we will
investigate the mechanisms Pseudomonas aeruginosa employs, such as recently identified microbial oxylipins,
to modulate macrophage inflammation during host defense at damaged tissues, and impact overall wound
healing. In vitro studies in immunometabolism support the prospects of modulating metabolic pathways for
therapeutic benefits. However, the therapeutic potential remains unclear without understanding how metabolism
regulates immune cell function in vivo. This study will demonstrate that imaging the endogenous fluorescence of
metabolic coenzymes is a valuable non-invasive and label-free approach to fill these gaps in our understanding
and better inform the development of new therapies.

## Key facts

- **NIH application ID:** 10188913
- **Project number:** 1R21AI159312-01
- **Recipient organization:** UNIVERSITY OF WISCONSIN-MADISON
- **Principal Investigator:** Anna Huttenlocher
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $230,676
- **Award type:** 1
- **Project period:** 2021-03-17 → 2023-02-28

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10188913

## Citation

> US National Institutes of Health, RePORTER application 10188913, Imaging Immunometabolism in live animals during host defense (1R21AI159312-01). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10188913. Licensed CC0.

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