A Staphylococcus aureus pore-forming toxin subverts the activity of ADAM10 to cause lethal infection in mice

Abstract

Staphylococcus aureus produces pore-forming toxins, such as α-hemolysin, that damage epithelial cell layers, causing disease. In this issue, Inoshima et al. report that the cellular receptor for α-hemolysin—the metalloprotease ADAM10—is essential for lethal pneumonia caused by S. aureus infection in mice. The authors suggest that the combined effect of α-hemolysin on pore formation and in activating ADAM10 cleavage of the adherens junction protein E-cadherin disrupts the barrier function of the lung epithelium. 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 alone1,2. This pathogen secretes α-hemolysin, a pore-forming cytotoxin that contributes to the pathogenesis of pneumonia3,4,5. α-hemolysin injures epithelial cells in vitro by interacting with its receptor, the zinc-dependent metalloprotease ADAM10 (ref. 6). We show here 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 in response to Hla; similarly, toxin-dependent 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 α-hemolysin can usurp the metalloprotease activity of its receptor reveals a previously unknown 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 to attenuate α-hemolysin-induced disease.