title: Differential expression of the bone and the liver tissue non-specific alkaline phosphatase isoforms in brain tissues.
abstract: The enzyme tissue non-specific alkaline phosphatase (TNAP) belongs to the ectophosphatase family. It is present in large amounts in bone in which it plays a role in mineralization but little is known about its function in other tissues. Arguments are accumulating for its involvement in the brain, in particular in view of the neurological symptoms accompanying human TNAP deficiencies. We have previously shown, by histochemistry, alkaline phosphatase (AP) activity in monkey brain vessels and parenchyma in which AP exhibits specific patterns. Here, we clearly attribute this activity to TNAP expression rather than to other APs in primates (human and marmoset) and in rodents (rat and mouse). We have not found any brain-specific transcripts but our data demonstrate that neuronal and endothelial cells exclusively express the bone TNAP transcript in all species tested, except in mouse neurons in which liver TNAP transcripts have also been detected. Moreover, we highlight the developmental regulation of TNAP expression; this also acts during neuronal differentiation. Our study should help to characterize the regulation of the expression of this ectophosphatase in various cell types of the central nervous system.
authors.affiliation: Unité de Pathologie Cellulaire et Génétique, UPRES-EA2493, Université de Versailles Saint Quentin en Yvelines, 78035 Versailles, France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Brun-Heath
authors.forename: Myriam
authors.initials: M
authors.lastname: Ermonval
authors.forename: Elodie
authors.initials: E
authors.lastname: Chabrol
authors.forename: Jinsong
authors.initials: J
authors.lastname: Xiao
authors.forename: Miklós
authors.initials: M
authors.lastname: Palkovits
authors.forename: Ruth
authors.initials: R
authors.lastname: Lyck
authors.forename: Florence
authors.initials: F
authors.lastname: Miller
authors.forename: Pierre-Olivier
authors.initials: PO
authors.lastname: Couraud
authors.forename: Etienne
authors.initials: E
authors.lastname: Mornet
authors.forename: Caroline
authors.initials: C
authors.lastname: Fonta
mesh_terms: D000469:Alkaline Phosphatase / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001808:Blood Vessels / Q000201:enzymology; D001842:Bone and Bones / Q000201:enzymology*; D001921:Brain / Q000201:enzymology*; D002460:Cell Line; D004622:Embryo, Mammalian / Q000033:anatomy & histology / Q000201:enzymology; D006801:Humans; D007527:Isoenzymes / Q000378:metabolism*; D008099:Liver / Q000201:enzymology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011323:Primates; D017434:Protein Structure, Tertiary; D051381:Rats; D016415:Sequence Alignment; D014018:Tissue Distribution
chemical_list: D007527:Isoenzymes; C548267:ALPL protein, human; D000469:Alkaline Phosphatase