GFAP and Alexander disease: It has been reported that the upregulation of astrocytic Ca2+ is also essential for GFAP upregulation (a marker for reactive astrocytes) in diverse neuropathologies, including AD,59 Alexander disease,60 photothrombosis,59 and traumatic brain injury,61 whereas abrogation of aberrant Ca2+ signals (via IP3 receptor KO, etc.)strongly suppresses GFAP upregulation and subsequent inflammatory phenotypes.