The S treptococcus pyogenes NAD + glycohydrolase modulates epithelial cell PAR ylation and HMGB 1 release

Summary S treptococcus pyogenes uses the cytolysin streptolysin O ( SLO ) to translocate an enzyme, the S . pyogenes   NAD + glycohydrolase ( SPN ), into the host cell cytosol. However, the function of SPN in this compartment is not known. As a complication, many S . pyogenes strains express a SPN variant lacking NAD + glycohydrolase ( NAD ase) activity. Here, we show that SPN modifies several SLO ‐ and NAD + ‐dependent host cell responses in patterns that correlate with NAD ase activity. SLO pore formation results in hyperactivation of the cellular enzyme poly‐ ADP ‐ribose polymerase‐1 ( PARP ‐1) and production of polymers of poly‐ ADP ‐ribose ( PAR ). However, while SPN NAD ase activity moderates PARP ‐1 activation and blocks accumulation of PAR , these processes continued unabated in the presence of NAD ase‐inactive SPN . Temporal analyses revealed that while PAR production is initially independent of NAD ase activity, PAR rapidly disappears in the presence of NAD ase‐active SPN , host cell ATP is depleted and the pro‐inflammatory mediator high‐mobility group box‐1 ( HMGB 1) protein is released from the nucleus by a PARP ‐1‐dependent mechanism. In contrast, HMGB 1 is not released in response to NAD ase‐inactive SPN and instead the cells release elevated levels of interleukin‐8 and tumour necrosis factor‐α. Thus, SPN and SLO combine to induce cellular responses subsequently influenced by the presence or absence of NAD ase activity.