title: Atrial natriuretic peptide is eliminated from the brain by natriuretic peptide receptor-C-mediated brain-to-blood efflux transport at the blood-brain barrier.
abstract: Cerebral atrial natriuretic peptide (ANP), which is generated in the brain, has functions in the regulation of brain water and electrolyte balance, blood pressure and local cerebral blood flow, as well as in neuroendocrine functions. However, cerebral ANP clearance is still poorly understood. The purpose of this study was to clarify the mechanism of blood-brain barrier (BBB) efflux transport of ANP in mouse. Western blot analysis showed expression of natriuretic peptide receptor (Npr)-A and Npr-C in mouse brain capillaries. The brain efflux index (BEI) method confirmed elimination of [(125)I]human ANP (hANP) from mouse brain across the BBB. Inhibition studies suggested the involvement of Npr-C in vivo. Furthermore, rapid internalization of [(125)I]hANP by TM-BBB4 cells (an in vitro BBB model) was significantly inhibited by Npr-C inhibitors and by two different Npr-C-targeted short interfering RNAs (siRNAs). Finally, treatment with 1α,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3)) significantly increased Npr-C expression in TM-BBB4 cells, as determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based targeted absolute proteomics. Our results indicate that Npr-C mediates brain-to-blood efflux transport of ANP at the mouse BBB as a pathway of cerebral ANP clearance. It seems likely that levels of natriuretic peptides in the brain are modulated by 1,25(OH)(2)D(3) through upregulation of Npr-C expression at the BBB.
authors.affiliation: Division of Membrane Transport and Drug Targeting, Graduate School of Pharmaceutical Sciences, Tohoku University, Aoba-ku, Sendai, Japan.
authors.forename: Shingo
authors.initials: S
authors.lastname: Ito
authors.forename: Sumio
authors.initials: S
authors.lastname: Ohtsuki
authors.forename: Yuki
authors.initials: Y
authors.lastname: Katsukura
authors.forename: Miho
authors.initials: M
authors.lastname: Funaki
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Koitabashi
authors.forename: Akihiko
authors.initials: A
authors.lastname: Sugino
authors.forename: Sho
authors.initials: S
authors.lastname: Murata
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Terasaki
mesh_terms: D000818:Animals; D009320:Atrial Natriuretic Factor / Q000378:metabolism*; D001812:Blood-Brain Barrier / Q000502:physiology*; D015153:Blotting, Western; D001923:Brain Chemistry / Q000187:drug effects*; D002117:Calcitriol / Q000494:pharmacology; D002120:Calcium Channel Agonists / Q000494:pharmacology; D002196:Capillaries / Q000378:metabolism; D002460:Cell Line; D002851:Chromatography, High Pressure Liquid; D042783:Endothelial Cells / Q000378:metabolism; D006801:Humans; D007457:Iodine Radioisotopes; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D020098:Natriuretic Peptide, C-Type / Q000096:biosynthesis*; D034741:RNA, Small Interfering / Q000235:genetics; D017461:Receptors, Atrial Natriuretic Factor / Q000096:biosynthesis / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D053719:Tandem Mass Spectrometry; D014162:Transfection
chemical_list: D002120:Calcium Channel Agonists; D007457:Iodine Radioisotopes; D034741:RNA, Small Interfering; D020098:Natriuretic Peptide, C-Type; D009320:Atrial Natriuretic Factor; D017461:Receptors, Atrial Natriuretic Factor; C091715:atrial natriuretic factor receptor A; C073616:atrial natriuretic factor receptor C; D002117:Calcitriol