A Staphylococcus aureus Pore-Forming Toxin Subverts the Activity of ADAM10 to Cause Lethal Infection

Staphylococcus aureus is a major cause of human disease, responsible for half a million infections and approximately 20,000 deaths per year in the United States alone (1,2). This pathogen secretes α-hemolysin, a pore-forming cytotoxin that contributes to the pathogenesis of pneumonia (3–5). α-hemolysin injures epithelial cells by interacting with its receptor, the zinc-dependent metalloprotease ADAM10 (6). We show that mice harboring a conditional disruption of the Adam10 gene in lung epithelium are resistant to lethal pneumonia. Investigation of the molecular mechanism of toxin-receptor function revealed that α-hemolysin upregulates ADAM10 metalloprotease activity in alveolar epithelial cells, resulting in cleavage of the adherens junction protein E-cadherin. Cleavage is associated with disruption of epithelial barrier function, contributing to the pathogenesis of lethal acute lung injury. A metalloprotease inhibitor of ADAM10 prevents E-cadherin cleavage; similarly, E-cadherin proteolysis and barrier disruption is attenuated in ADAM10 knockout mice. Together, these data attest to the function of ADAM10 as the cellular receptor for α-hemolysin. The observation that Hla can usurp the metalloprotease activity of its receptor reveals a novel mechanism of pore-forming cytotoxin action in which pathologic insults are not solely the result of irreversible membrane injury, and defines ADAM10 inhibition as a strategy for disease modification.