Differential expression of the bone and the liver tissue non-specific alkaline phosphatase isoforms in brain tissues

• Published in: Cell and tissue research 2011-03, Vol.343 (3), p.521-536
• Main Authors: Brun-Heath, Isabelle, Ermonval, Myriam, Chabrol, Elodie, Xiao, Jinsong, Palkovits, Miklós, Lyck, Ruth, Miller, Florence, Couraud, Pierre-Olivier, Mornet, Etienne, Fonta, Caroline
• Format: Article
• Language: English
• Subjects: alkaline phosphatase; Alkaline Phosphatase - genetics; Alkaline Phosphatase - metabolism; Alkalinity; Amino Acid Sequence; Animals; Base Sequence; Biomedical and Life Sciences; Biomedicine; Blood Vessels - enzymology; Bone and Bones - enzymology; Bones; Brain; Brain - enzymology; Callithrix; Cell Line; Embryo, Mammalian - anatomy & histology; Embryo, Mammalian - enzymology; endothelial cells; Enzymes; Gene expression; gene expression regulation; histochemistry; Human Genetics; Humans; Isoenzymes - metabolism; Life Sciences; Liver; Liver - enzymology; Mice; Mice, Inbred C57BL; mineralization; Models, Molecular; Molecular Medicine; Molecular Sequence Data; monkeys; neurons; Neurons and Cognition; parenchyma; Phosphatases; Phosphates; Primates; Protein Structure, Tertiary; Proteomics; Rats; Regular Article; Sequence Alignment; Tissue Distribution; Tissues
• ISSN: 0302-766X; 1432-0878
• DOI: 10.1007/s00441-010-1111-4

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.