BE/MEAM Seminar: “Microbes in Biomechanics” (Christopher J. Hernandez)

This event will be held virtually on Zoom – check email for link or contact ksas@seas.upenn.edu.

The idea that mechanical stresses influence the growth and form of organs and organisms originated in the 1800s and is the basis for the modern study of biomechanics and mechanobiology. Biomechanics and mechanobiology are well studied in eukaryotic systems, yet eukaryotes represent only a small portion of the diversity and abundance of life on Earth. Bacteria exhibit broad influences on human health (as both pathogens and as beneficial components of the gut microbiome) and processes used in biotechnology and synthetic biology. Over the past eight years my group has explored mechanobiology within individual bacteria and the effects of changes in the composition of commensal bacterial communities on the biomechanics in the musculoskeletal system.

The ability of the bacteria to not only resist mechanical loads (biomechanics) but also to respond to changes in the mechanical environment (mechanobiology) is necessary for survival. Here I describe a novel microfluidic platform used to explore the biomechanics and mechanobiology of individual, live bacteria. I discuss work from my group demonstrating that mechanical stress within the bacterial cell envelope can influence the assembly and function of multicomponent efflux pumps used by bacteria to resist toxins and antibiotics. Additionally, I share some of our more recent work showing that mechanical stress and strain within the bacterial cell envelope can stimulate a bacterial two-component system controlling gene expression. Our findings demonstrate that bacteria, like mammalian cells, have mechanosensitive systems that are key to survival.

In musculoskeletal disease, bacteria are commonly viewed as sources of infection. However, in the past decade the studies by my group and others have suggested that commensal bacteria – the microbiome – can modulate the pathogenesis of musculoskeletal disorders. My group is among the first to study the effects of the gut microbiome on orthopaedic disorders. Here I provide an introduction to the microbiome and current concepts of how modifications to the gut microbiome could influence the musculoskeletal system. Specifically, I discuss studies from my group which are the first to demonstrate that the gut microbiome influences bone biomechanics and the development of infection of orthopaedic implants.