Hydrogen sulfide-linked sulfhydration of NF-κB mediates its antiapoptotic actions

Nuclear factor κB (NF-κB) is an antiapoptotic transcription factor. We show that the antiapoptotic actions of NF-κB are mediated by hydrogen sulfide (H ₂S) synthesized by cystathionine gamma-lyase (CSE). TNF-α treatment triples H ₂S generation by stimulating binding of SP1 to the CSE promoter. H ₂S generated by CSE stimulates DNA binding and gene activation of NF-κB, processes that are abolished in CSE-deleted mice. As CSE deletion leads to decreased glutathione levels, resultant oxidative stress may contribute to alterations in CSE mutant mice. H ₂S acts by sulfhydrating the p65 subunit of NF-κB at cysteine-38, which promotes its binding to the coactivator ribosomal protein S3 (RPS3). Sulfhydration of p65 predominates early after TNF-α treatment, then declines and is succeeded by a reciprocal enhancement of p65 nitrosylation. In CSE mutant mice, antiapoptotic influences of NF-κB are markedly diminished. Thus, sulfhydration of NF-κB appears to be a physiologic determinant of its antiapoptotic transcriptional activity.