Targeting NLRP3 and Staphylococcal pore-forming toxin receptors in human-induced pluripotent stem cell-derived macrophages
Seong Hoong Chow, Pankaj Deo, Amy Yeung, Xenia Kostoulias, Yusun Jeon, Meiling Gao, Azadeh Seidi, Françios A.B. Olivier, Sushmita Sridhar, Cara Nethercott, David R. Cameron, Avril A. B. Robertson, R. Robert, Charles R. Mackay, Ana Traven, Zi‐Bing Jin, Christine Hale, Gordon Dougan, Anton Y. Peleg, Thomas Naderer
Abstract
Staphylococcus aureus causes necrotizing pneumonia by secreting toxins such as leukocidins that target front-line immune cells. The mechanism by which leukocidins kill innate immune cells and trigger inflammation during S. aureus lung infection, however, remains unresolved. Here, we explored human-induced pluripotent stem cell-derived macrophages (hiPSC-dMs) to study the interaction of the leukocidins Panton-Valentine leukocidin (PVL) and LukAB with lung macrophages, which are the initial leukocidin targets during S. aureus lung invasion. hiPSC-dMs were susceptible to the leukocidins PVL and LukAB and both leukocidins triggered NLPR3 inflammasome activation resulting in IL-1β secretion. hiPSC-dM cell death after LukAB exposure, however, was only temporarily dependent of NLRP3, although NLRP3 triggered marked cell death after PVL treatment. CRISPR/Cas9-mediated deletion of the PVL receptor, C5aR1, protected hiPSC-dMs from PVL cytotoxicity, despite the expression of other leukocidin receptors, such as CD45. PVL-deficient S. aureus had reduced ability to induce lung IL-1β levels in human C5aR1 knock-in mice. Unexpectedly, inhibiting NLRP3 activity resulted in increased wild-type S. aureus lung burdens. Our findings suggest that NLRP3 induces macrophage death and IL-1β secretion after PVL exposure and controls S. aureus lung burdens.