Peroxiredoxin-mediated HMGB1 oxidation and secretion in response to inflammatory stimuli

Abstract

The nuclear protein HMGB1 (high mobility group box 1) is secreted by monocytesmacrophages in response to inflammatory stimuli and serves as a danger-associated molecular pattern. Acetylation and phosphorylation of HMGB1 are implicated in the regulation of its nucleocytoplasmic translocation for secretion, although inflammatory stimuli are also known to induce H 2 O 2 production. Here we show that H 2 O 2 -induced oxidation of HMGB1 that results in formation of an intramolecular disulphide bond between Cys 23 and Cys 45 is necessary and sufficient for its nucleocytoplasmic translocation and secretion. The oxidation is catalysed by peroxiredoxin I (PrxI) and PrxII, which are first oxidized by H 2 O 2 and then transfer their disulphide oxidation state to HMGB1. The disulphide form of HMGB1 showed a higher affinity for the nuclear exportin CRM1 compared with the reduced form.Lipopolysaccharide (LPS)-induced HMGB1 secretion was greatly attenuated in macrophages derived from PrxI or PrxII knockout mice, as was the LPS-induced increase in serum HMGB1 levels in these mice.