Several virulence lipids populate the outer cell wall of pathogenic mycobacteria (Jackson, 2014). Phthiocerol dimycocerosate (PDIM), one of the most abundant outer membrane lipids (Anderson, 1929), plays important roles in both defending against host antimicrobial programs (Camacho et al., 2001; Cox et al., 1999; Murry et al., 2009) and in evading these programs altogether (Cambier et al., 2014a; Rousseau et al., 2004). Immediately following infection, mycobacteria rely on PDIM to evade Myd88-dependent recruitment of microbicidal monocytes which can clear infection (Cambier et al., 2014b). To circumvent the limitations in using genetics to understand virulence lipids, we developed a chemical approach to track PDIM during Mycobacterium marinum infection of zebrafish. We found that PDIM's methyl-branched lipid tails enabled it to spread into host epithelial membranes to prevent immune activation. Additionally, PDIM's affinity for cholesterol promoted this phenotype; treatment of zebrafish with statins, cholesterol synthesis inhibitors, decreased spreading and provided protection from infection. This work establishes that interactions between host and pathogen lipids influence mycobacterial infectivity and suggests the use of statins as tuberculosis preventive therapy by inhibiting PDIM spread.
- Carolyn R Bertozzi
- CJ Cambier
- Steven M Banik
- Joseph A Buonomo
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Animal experimentation: All experiments performed on zebrafish were in compliance with the U.S. National Institutes of Health guidelines. All animals were handled according to approved Stanford Institutional Animal Care and Use Committee protocol APLAC-30262.
- Christina L Stallings, Washington University School of Medicine, United States
- Received: July 2, 2020
- Accepted: November 23, 2020
- Accepted Manuscript published: November 23, 2020 (version 1)
? 2020, Cambier et al.
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