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Neural Regen Res. 2018 Feb;13(2):252-256. doi: 10.4103/1673-5374.226394.

Dabrafenib, an inhibitor of RIP3 kinase-dependent necroptosis, reduces ischemic brain injury.

Author information

1
Ottawa Hospital Research Institute; University of Ottawa, Brain and Mind Institute; Canadian Partnership for Storke Recovery, Ottawa, Canada.
2
Ottawa Hospital Research Institute; Canadian Partnership for Storke Recovery, Ottawa, Canada.
3
University of Ottawa Heart Institute, Ottawa, Canada.

Abstract

Ischemic brain injury triggers neuronal cell death by apoptosis via caspase activation and by necroptosis through activation of the receptor-interacting protein kinases (RIPK) associated with the tumor necrosis factor-alpha (TNF-α)/death receptor. Recent evidence shows RIPK inhibitors are neuroprotective and alleviate ischemic brain injury in a number of animal models, however, most have not yet undergone clinical trials and safety in humans remains in question. Dabrafenib, originally identified as a B-raf inhibitor that is currently used to treat melanoma, was later revealed to be a potent RIPK3 inhibitor at micromolar concentrations. Here, we investigated whether Dabrafenib would show a similar neuroprotective effect in mice subjected to ischemic brain injury by photothrombosis. Dabrafenib administered intraperitoneally at 10 mg/kg one hour after photothrombosis-induced focal ischemic injury significantly reduced infarct lesion size in C57BL6 mice the following day, accompanied by a markedly attenuated upregulation of TNF-α. However, subsequent lower doses (5 mg/kg/day) failed to sustain this neuroprotective effect after 4 days. Dabrafenib blocked lipopolysaccharides-induced activation of TNF-α in bone marrow-derived macrophages, suggesting that Dabrafenib may attenuate TNF-α-induced necroptotic pathway after ischemic brain injury. Since Dabrafenib is already in clinical use for the treatment of melanoma, it might be repurposed for stroke therapy.

KEYWORDS:

Dabrafenib; inflammation; ischemic brain injury; macrophage; microglia; necroptosis; neural regeneration; photothrombosis; receptor-interacting protein kinases; stroke; tumor necrosis factor-alpha

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