title: B(0)AT2 (SLC6A15) is localized to neurons and astrocytes, and is involved in mediating the effect of leucine in the brain.
abstract: The B(0)AT2 protein is a product of the SLC6A15 gene belonging to the SLC6 subfamily and has been shown to be a transporter of essential branched-chain amino acids. We aimed to further characterize the B(0)AT2 transporter in CNS, and to use Slc6a15 knock out (KO) mice to investigate whether B(0)AT2 is important for mediating the anorexigenic effect of leucine. We used the Slc6a15 KO mice to investigate the role of B(0)AT2 in brain in response to leucine and in particular the effect on food intake. Slc6a15 KO mice show lower reduction of food intake as well as lower neuronal activation in the ventromedial hypothalamic nucleus (VMH) in response to leucine injections compared to wild type mice. We also used RT-PCR on rat tissues, in situ hybridization and immunohistochemistry on mouse CNS tissues to document in detail the distribution of SLC6A15 on gene and protein levels. We showed that B(0)AT2 immunoreactivity is mainly neuronal, including localization in many GABAergic neurons and spinal cord motor neurons. B(0)AT2 immunoreactivity was also found in astrocytes close to ventricles, and co-localized with cytokeratin and diazepam binding inhibitor (DBI) in epithelial cells of the choroid plexus. The data suggest that B(0)AT2 play a role in leucine homeostasis in the brain.
authors.affiliation: Department of Neuroscience, Functional Pharmacology, Uppsala University, Uppsala, Sweden.
authors.forename: Maria G A
authors.initials: MG
authors.lastname: Hägglund
authors.forename: Sahar
authors.initials: S
authors.lastname: Roshanbin
authors.forename: Erik
authors.initials: E
authors.lastname: Löfqvist
authors.forename: Sofie V
authors.initials: SV
authors.lastname: Hellsten
authors.forename: Victor C O
authors.initials: VC
authors.lastname: Nilsson
authors.forename: Aniruddha
authors.initials: A
authors.lastname: Todkar
authors.forename: Yinan
authors.initials: Y
authors.lastname: Zhu
authors.forename: Olga
authors.initials: O
authors.lastname: Stephansson
authors.forename: Jana
authors.initials: J
authors.lastname: Drgonova
authors.forename: George R
authors.initials: GR
authors.lastname: Uhl
authors.forename: Helgi B
authors.initials: HB
authors.lastname: Schiöth
authors.forename: Robert
authors.initials: R
authors.lastname: Fredriksson
mesh_terms: D026921:Amino Acid Transport Systems, Neutral / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D001253:Astrocytes / Q000378:metabolism*; D001921:Brain / Q000378:metabolism*; D004435:Eating; D039561:Eukaryotic Initiation Factor-4E / Q000235:genetics / Q000378:metabolism; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D005838:Genotype; D007930:Leucine / Q000008:administration & dosage*; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D021381:Protein Transport; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D013116:Spinal Cord / Q000378:metabolism; D058570:TOR Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism
chemical_list: D026921:Amino Acid Transport Systems, Neutral; D039561:Eukaryotic Initiation Factor-4E; D012333:RNA, Messenger; C508691:Slc6a15 protein, mouse; D058570:TOR Serine-Threonine Kinases; D007930:Leucine