| Project Detail |
Clostridium perfringens is a widely distributed and successful pathogen that causes severe diseases in animals and humans. It produces an arsenal of virulence factors, many of them belonging to the hemolysin family of ß-pore forming toxins (ßPFTs). The widespread use of these toxins in C. perfringens and other pathogenic bacteria underpins the notion that they are most likely important virulence factors in many diseases. Knowledge about the role of many C. perfringens hemolysin ßPFTs is, however, still limited. Our recent discoveries of CD31 as the membrane receptor for C. perfingens beta-toxin (CPB) and our elucidation of the CPB pore structure using cryo-EM have made important contributions to the knowledge on this family of toxins in clostridia. More recently, I extended my research to other poorly characterized clostridial hemolysin ßPFTs and generated interesting preliminary data on the receptor and cell type specificity of NetF and NetG. Building upon existing strengths in my group, I propose a three-step approach to deepen research on clostridial hemolysin ßPFTs. First, I aim to define the receptor binding domain on CPB to determine the exact molecular interaction between CPB and its receptor, CD31. Second, I will investigate the interaction between NetF and capillary morphogenesis protein 2 (CMG2). CMG2 is one of the two known receptors for protective antigen (PA) of the Bacillus anthracis anthrax toxin, and we demonstrated that CMG2 expression on target cells is essential for NetF toxicity. I will now investigate whether NetF binds to CMG2 via the same receptor domains as PA, or if it uses a similar mechanism as CPB and targets the membrane proximal Ig-like domain, which shares striking structural homology to the binding domain we indentifed on CD31. Finally, I will search for the membrane receptor of NetG using genome wide CRISPR/Cas9 loss of function screens. The goal of my project is to determine the molecular basis for the interaction of these three highly potent clostridial hemolysin ßPFT with target cells and receptors. This will aid in understanding the roles of these toxins in C. perfringens infections. Results may highlight molecular mechanisms and structures that confer receptor, cell-type and species specificity for multiple related PFTs from C. perfringens and other pathogens, such as B. anthracis. My research offers novel opportunities to integrate work on animal pathogens, such as C. perfringens, into a one-health approach. Common structures and mechanisms used by different bacterial pathogens in humans and animals are valuable targets for the development of novel anti-virulence strategies. |
