Chemical tools to reveal the sterol lipid interactome in the syphilis agent treponema pallidum

The National Institute of Allergy and Infectious Diseases awarded The Leland Stanford Junior University $152,600 on November 27, 2026, under the Allergy and Infectious Diseases Research program (CFDA 93.855) to develop chemical tools that reveal the sterol lipid interactome in Treponema pallidum, the bacterium that causes syphilis.

The research combines sequence- and structure-bioinformatics, protein biochemistry, chemical biology, and genetic manipulation to identify proteins critical to lipid homeostasis in T. pallidum and elucidate the mechanisms through which the pathogen procures lipids, including sterols, from its host. The project addresses the poorly understood acquisition of neutral lipids, phospholipids, and cholesterol by T. pallidum despite its lack of biosynthetic machinery for most lipids, which is hypothesized to support the spirochete's immune evasion mechanisms. The proposed approaches are intended to expand the technical toolkit available for studying T. pallidum and other spirochetes and to reveal potential therapeutic design avenues by clarifying pathogenic mechanisms.

Performance occurs in Palo Alto, California, with work extending through May 31, 2029. This is a Project Grant, the assistance type under which NIH funds investigator-initiated research proposals.

Abstract

Syphilis is a sexually transmitted bacterial infection of the spirochete treponema pallidum and has plagued humanity for centuries, yet little is known about the biology of T. Pallidum. With the number of cases rising globally in tandem with the increased burden of antimicrobial resistance, the expansion of the knowledge surrounding T. Pallidum biology is critical for the development of effective therapies. The goal of this project is to deduce the mechanisms through which T. Pallidum procures lipids, including sterols, from its host. Identifying the routes used by the pathogen to obtain essential metabolites will provide a better understanding of its pathogenicity and reveal potential avenues for strategic therapeutic design. Despite lacking the machinery necessary for the biosynthesis of most lipids, the cellular envelope of T. Pallidum is rich with neutral lipids, phospholipids, and cholesterol. How IT acquires these is poorly understood and is hypothesized to assist the spirochete in its immune evasion mechanisms. Because in vitro culture of T. Pallidum has only recently been established, very few techniques have been used to study gene and protein function in the cell. The reliance of T. Pallidum on its host presents a unique avenue for investigating the pathogenicity of the spirochete. To identify proteins critical to the maintenance of lipid homeostasis in T. Pallidum, we will combine sequence- and structure-bioinformatics, protein biochemistry, chemical biology, and genetic manipulation to reveal the lipid interactome of the T. Pallidum. These proposed approaches for studying the pathogen will expand the set of techniques available for continued study of the bacterium and other spirochetes. With the focus on broadening our understanding of the lipid interactome of T. Pallidum, novel aspects of this proposal include 1) characterization of lipid-interacting proteins expressed in T. Pallidum, 2) quantification of the lipidome of T. Pallidum relative to its rabbit epithelial cell host, 3) development of targeted and chemoproteomic methods in T. Pallidum for identification of sterol binding proteins, and 4) development of a gene silencing technique for in vitro cultures of T. Pallidum. This goals of this project will expand on my PHD training in organic chemistry and mammalian cell biology and allow me to practice more complex models of mammalian and bacterial cell culture as well as protein biochemistry and structural biology, which will be especially useful for my transition into future protein-based therapeutic research.