PARP-1 regulates the expression of caspase-11

Poly(ADP-ribose) polymerase-1 (PARP-1) is a multifunctional enzyme that regulates DNA repair, cell death and transcription of inflammatory proteins. In the present study, we present evidence that PARP-1 regulates the expression of caspase-11 following lipopolysaccharide (LPS) stimulation. Knockdown of PARP-1 suppressed the LPS-induced expression of caspase-11 at both mRNA and protein levels as well as caspase-11 promoter activity. Importantly, PARP-1 was recruited to the caspase-11 promoter region containing predicted nuclear factor (NF)-κB-binding sites when examined by chromatin immunoprecipitation assay. However, knockdown of PARP-1 did not suppress the expression of caspase-11 induced by interferon-γ that activates signal transducer and activator of transcription 1 but not NF-κB. PARP-1 enzymatic activity was not required for the caspase-11 upregulation since pharmacological inhibitors of PARP-1 did not suppress the induction of caspase-11. Our results suggest that PARP-1, as a transcriptional cofactor for NF-κB, regulates the induction of caspase-11 at a transcriptional level.