# Identification of novel anti-virulence compounds against Pathogenic Burkholderia

> **NIH NIH R21** · BOSTON CHILDREN'S HOSPITAL · 2022 · $221,250

## Abstract

Project Abstract
The long-term goal of this project is to develop novel therapeutics for the treatment of the Gram-negative
pathogens in the Burkholderia genus which includes the Burkholderia cepacia complex (BCC) and
Burkholderia pseudomallei. These pathogens cause serious, chronic lung infections and are also major causes
of healthcare-associated infections. Treatment of infections caused by these pathogens is often difficult due to
the broad-spectrum antibiotic resistance that is commonly seen. The development of novel therapeutics to
treat these pathogens is critically needed. Our published work analyzing the genomic diversity of isolates of the
BCC species B. dolosa and B. multivorans collected from people with CF has led to the discovery that the fixL
gene appears to be under strong positive selection. FixL has been described in Rhizobium and Caulobacter as
a sensory histidine kinase of a two-component system that detects oxygen tension and phosphorylates the
transcription factor FixJ under low oxygen conditions. Our previous work has found that the BCC FixLJ system
is required for pathogenesis and modulation of this pathway has profound effects of virulence. Interestingly,
constructs carrying evolved FixL variants associated with periods of clinical decline in patients were more
virulent in multiple infection models compared to isogenic constructs carrying ancestral FixL variants. These
more virulent FixL sequences had lower FixLJ activity than less virulent constructs carrying ancestral FixL
variants demonstrating that increased FixLJ activity is determinantal to virulence. We hypothesize that we can
reduce Burkholderia virulence by activating the FixLJ pathway. By targeting virulence, we predict that the
bacteria would no longer be able to infect or persist within the host. In the first aim of this project we will identify
compounds that activate FixLJ using a high-throughput screen with a Burkholderia fix pathway reporter strain.
In Aim 2 we will evaluate promising lead compounds identified in Aim 1 for their in vitro effectiveness at
reducing virulence of multiple Burkholderia species using an in vitro macrophage assay. We also will evaluate
the toxicity of lead compounds using cell culture. We plan to identify 3-4 lead compounds with an EC50 in the
low micromolar (1-10) range and a toxicity at least 5-fold higher than the EC50. These lead compounds will be
further developed into therapies for use to treat Burkholderia infections.

## Key facts

- **NIH application ID:** 10374147
- **Project number:** 5R21AI159211-02
- **Recipient organization:** BOSTON CHILDREN'S HOSPITAL
- **Principal Investigator:** Matthew M Schaefers
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $221,250
- **Award type:** 5
- **Project period:** 2021-03-17 → 2023-11-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10374147

## Citation

> US National Institutes of Health, RePORTER application 10374147, Identification of novel anti-virulence compounds against Pathogenic Burkholderia (5R21AI159211-02). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10374147. Licensed CC0.

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