Nanomechanical mechanisms of Lyme disease spirochete motility enhancement in extracellular matrix

Abstract

As opposed to pathogens passively circulating in the body fluids of their host, pathogenic species within the Spirochetes phylum are able to actively coordinate their movement in the host to cause systemic infections. Based on the unique morphology and high motility of spirochetes, we hypothesized that their surface adhesive molecules might be suitably adapted to aid in their dissemination strategies. Designing a system that mimics natural environmental signals, which many spirochetes face during their infectious cycle, we observed that a subset of their surface proteins, particularly Decorin binding protein (Dbp) A/B, can strongly enhance the motility of spirochetes in the extracellular matrix of the host. Using single-molecule force spectroscopy, we disentangled the mechanistic details of DbpA/B and decorin/laminin interactions. Our results show that spirochetes are able to leverage a wide variety of adhesion strategies through force-tuning transient molecular binding to extracellular matrix components, which concertedly enhance spirochetal dissemination through the host. Martin Strnad, Yoo Jin Oh, and colleagues use single-molecule force spectroscopy and an extracellular matrix (ECM) analog that mimics natural tick feeding to show that the surface proteins DbpA/B can enhance spirochete motility in the ECM of the host. These results show that spirochetes can tune their transient molecular binding to ECM components to enhance spirochetal dissemination through the host.