EN
In ischemic stroke, the necrotic core is surrounded by a zone of infl ammation, in which delayed cell death aggravates the initial insult. Here, we provide evidence that the receptor for advanced glycation end products (RAGE) functions as a sensor of necrotic cell death and contributes to infl ammation and ischemic brain damage. The RAGE ligand high mobility group box 1 (HMGB1) was elevated in serum of stroke patients and was released from ischemic brain tissue in a mouse model of cerebral ischemia. A neutralizing anti-HMGB1 antibody and HMGB1 box A, an antagonist of HMGB1 at the receptor RAGE, ameliorated ischemic brain damage. Interestingly, genetic RAGE defi ciency and the decoy receptor soluble RAGE (sRAGE) reduced the infarct size. In vitro, expression of RAGE in (micro)glial cells mediated the toxic effect of HMGB1. Addition of macrophages to neural cultures further enhanced the toxic effect of HMGB1. To test whether immigrant macrophages in the ischemic brain mediate the RAGE effect, we generated chimeric mice by transplanting RAGE-/- bone marrow to wild-type mice. RAGE defi ciency in bone marrow-derived cells signifi cantly reduced the infarct size. Thus, HMGB1-RAGE signaling links necrosis with macrophage activation and may provide a target for anti-infl ammatory therapy in stroke.