Carbon monoxide potently prevents ischemia-induced high-mobility group box 1 translocation and release and protects against lethal renal ischemia-reperfusion injury.

High-mobility group box 1 (HMGB1) is a chromatin-binding nuclear molecule that has potent proinflammatory effects once released by damaged cells. In some disease models, carbon monoxide (CO) exhibits anti-inflammatory and protective properties. Here, we investigated whether the protective effect of CO on renal ischemia-reperfusion injury is associated with the inhibition of HMGB1 translocation and release. A renal ischemia-reperfusion injury model was established with a 100% mortality rate in untreated mice. Pretreatment with the CO-releasing molecule-2 (CORM-2) resulted in 100% survival, maximal preservation of renal function, a marked reduction in pathological damage, and blunted upregulation of TLR4, RAGE, TNF-α, IL-1β, IL-6, and MCP1 mRNA. Interestingly, CORM-2 pretreatment almost completely inhibited ischemia-induced HMGB1 nucleocytoplasmic shuttling and release. This inhibition was associated with a decrease in nuclear histone acetyltransferase activity. Indeed, CORM-2 pretreatment inhibited the acetylation and release of HMGB1 during hypoxic culture of primary mouse renal tubular epithelia cells in vitro. Using the same renal ischemia-reperfusion injury model, neutralization of HMGB1 was protective, and administration of exogenous HMGB1 largely reversed the protective effect of CORM-2 on kidney ischemia-reperfusion injury. Thus, CORM-2-delivered CO protects against lethal renal ischemia-reperfusion injury. This protection is correlated with the prevention of HMGB1 nuclear-cytoplasmic translocation and release.