# Optogenetic approaches to dissect Rho GTPase signal transduction during neutrophil responses to inflammation

> **NIH NIH F31** · UNIVERSITY OF CALIFORNIA AT DAVIS · 2020 · $37,679

## Abstract

Atherosclerosis, the accumulation of arterial plaques that restrict blood flow, is the leading cause of mortality and
morbidity worldwide. Chronic inflammation is the key driver of disease progression, though no widespread
treatments exist that target underlying immunological factors. The pro-inflammatory activities of neutrophil are
fundamental to disease progression, so therapies that target neutrophil responses to inflammation offer
promising treatment alternatives for atherosclerosis. Neutrophils arrive in the early stages of plaque formation
via chemotaxis, and their pro-inflammatory functions, including superoxide production and NETosis, cause
extensive tissue damage, propagate immune cell activities, and lead to plaque destabilization. These behaviors
are coordinated by members of the Rho family of small GTPases, which act as “molecular switches” to activate
distinct signaling cascades at precise times and sub-cellular locations. Organizing decisive responses to complex
external cues requires information processing steps within the Rho GTPase network, such as feedback circuits
and crosstalk interactions, which shape GTPase activities. However, limitations in the ability to isolate individual
processing steps from bulk cellular responses have made it impossible to dissect their unique contributions to
final Rho GTPase outputs. Furthermore, a complex network of RhoGEFs and RhoGAPs regulate GTPase
signaling activities, though no systematic approaches have been taken to determine the roles of individual
proteins in coordinating Rho GTPase dynamics in neutrophils. This study proposes two specific aims to fill critical
gaps in our understanding of Rho GTPase signal transduction and enable the development of neutrophil-specific
atherosclerosis treatments. First, optogenetic tools for extrinsic Rho GTPase activation will be paired with
complementary red-shifted Rho GTPase FRET biosensors to determine crosstalk and feedback signaling
dynamics in a neutrophil model cell line. Second, automated live cell imaging assays with arrayed, systematic
RhoGEF and RhoGAP knockdown will be used to identify key regulators of Rho GTPase signaling responses to
inflammation and determine their roles in mediating neutrophil behaviors. This work will be carried out under the
supervision of Dr. Sean Collins (sponsor) and Dr. Karen Zito (Co-sponsor) at the University of California, Davis.
Together, Dr. Collins and Dr. Zito have the resources and specialized technical expertise to oversee the
successful completion of the research and training goals outlined in this application.

## Key facts

- **NIH application ID:** 9991461
- **Project number:** 1F31HL152621-01
- **Recipient organization:** UNIVERSITY OF CALIFORNIA AT DAVIS
- **Principal Investigator:** Dean Edward Natwick
- **Activity code:** F31 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $37,679
- **Award type:** 1
- **Project period:** 2020-07-01 → 2021-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9991461

## Citation

> US National Institutes of Health, RePORTER application 9991461, Optogenetic approaches to dissect Rho GTPase signal transduction during neutrophil responses to inflammation (1F31HL152621-01). Retrieved via AI Analytics 2026-05-26 from https://api.ai-analytics.org/grant/nih/9991461. Licensed CC0.

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