title: In vivo expression of aquaporin-4 by reactive microglia.
abstract: Aquaporin-4 (AQP4) is the most abundant aquaporin in the brain and it is widely accepted that this AQP is solely expressed by astrocytes and ependymal cells. AQP4 is particularly enriched in plasma membranes of ependymal cells and astrocyte membrane domains facing blood vessels and pia. AQP4 has gained much attraction due to its involvement in the physiopathology of brain edema, a major cause of death in humans. Consequently, it is of paramount importance to ascertain the phenotypic nature of AQP4 mRNA-expressing cells in the CNS before attempting future clinical studies aimed at minimizing the development of brain edema. We have used intranigral injections of lipopolysaccharide (LPS), a potent immunostimulant that causes disruption of the blood brain barrier, vasogenic edema, loss of reactive astrocytes and activation of microglial cells. These LPS-induced features are ideal for testing the possibility that reactive microglial cells express AQP4 in the adult brain. We have studied AQP4 at the mRNA and protein level. We provide strong evidence that reactive microglial cells highly express AQP4 mRNA and protein in response to LPS injections.
authors.affiliation: Departamento de Bioquímica, Bromatología, Toxicología y Medicina Legal, Facultad de Farmacia, Universidad de Sevilla, Spain.
authors.forename: Mayka
authors.initials: M
authors.lastname: Tomás-Camardiel
authors.forename: José L
authors.initials: JL
authors.lastname: Venero
authors.forename: R M
authors.initials: RM
authors.lastname: de Pablos
authors.forename: I
authors.initials: I
authors.lastname: Rite
authors.forename: Alberto
authors.initials: A
authors.lastname: Machado
authors.forename: Josefina
authors.initials: J
authors.lastname: Cano
mesh_terms: D000818:Animals; D000943:Antigens, Differentiation / Q000096:biosynthesis; D051401:Aquaporin 4; D020346:Aquaporins / Q000096:biosynthesis* / Q000235:genetics; D001923:Brain Chemistry; D001929:Brain Edema / Q000139:chemically induced / Q000378:metabolism* / Q000473:pathology; D005260:Female; D005904:Glial Fibrillary Acidic Protein / Q000096:biosynthesis; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D008070:Lipopolysaccharides / Q000494:pharmacology; D008636:Mesencephalon / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D017628:Microglia / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017208:Rats, Wistar; D013378:Substantia Nigra / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology
chemical_list: D000943:Antigens, Differentiation; C496032:Aqp4 protein, rat; D051401:Aquaporin 4; D020346:Aquaporins; D005904:Glial Fibrillary Acidic Protein; D008070:Lipopolysaccharides; D012333:RNA, Messenger