title: Localization of brain endothelial luminal and abluminal transporters with immunogold electron microscopy.
abstract: Immunogold electron microscopy has identified a variety of blood-brain barrier (BBB) proteins with transporter and regulatory functions. For example, isoforms of the glucose transporter, protein kinase C (PKC), and caveolin-1 are BBB specific. Isoform 1 of the facilitative glucose transporter family (GLUT1) is expressed solely in endothelial (and pericyte) domains, and approximately 75% of the protein is membrane-localized in humans. Evidence is presented for a water cotransport function of BBB GLUT1. A shift in transporter polarity characterized by increased luminal membrane GLUT1 is seen when BBB glucose transport is upregulated; but a greater abluminal membrane density is seen in the human BBB when GLUT1 is downregulated. PKC colocalizes with GLUT1 within these endothelial domains during up- and downregulation, suggesting that a PKC-mediated mechanism regulates human BBB glucose transporter expression. Occludin and claudin-5 (like other tight-junctional proteins) exhibit a restricted distribution, and are expressed solely within interendothelial clefts of the BBB. GFAP (glial fibrillary acidic protein) is uniformly expressed throughout the foot-processes and the entire astrocyte. But the microvascular-facing membranes of the glial processes that contact the basal laminae are also polarized, and their transporters may also redistribute within the astrocyte. Monocarboxylic acid transporter and water channel (Aquaporin-4) expression are enriched at the glial foot-process, and both undergo physiological modulation. We suggest that as transcytosis and efflux mechanisms generate interest as potential neurotherapeutic targets, electron microscopic confirmation of their site-specific expression patterns will continue to support the CNS drug discovery process.
authors.affiliation: Veterans Administration Greater Los Angeles Healthcare System, Los Angeles, California 90073, USA. cornford@ucla.edu
authors.forename: Eain M
authors.initials: EM
authors.lastname: Cornford
authors.forename: Shigeyo
authors.initials: S
authors.lastname: Hyman
mesh_terms: D000818:Animals; D001812:Blood-Brain Barrier / Q000187:drug effects / Q000502:physiology*; D001923:Brain Chemistry / Q000502:physiology*; D002196:Capillaries / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism*; D051242:Caveolin 1; D022461:Caveolins / Q000378:metabolism; D051272:Glucose Transporter Type 1; D006801:Humans; D007150:Immunohistochemistry; D016253:Microscopy, Immunoelectron; D027501:Monocarboxylic Acid Transporters / Q000378:metabolism; D009004:Monosaccharide Transport Proteins / Q000378:metabolism; D009457:Neuroglia / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism
chemical_list: C495540:CAV1 protein, human; D002352:Carrier Proteins; D051242:Caveolin 1; D022461:Caveolins; D051272:Glucose Transporter Type 1; D027501:Monocarboxylic Acid Transporters; D009004:Monosaccharide Transport Proteins; C490427:SLC16A7 protein, human; C495677:SLC2A1 protein, human; D011493:Protein Kinase C
references.citation: Acta Neuropathol. 1981;53(3):203-11
references.pmid: 6111887
references.citation: J Neurosci. 2003 Oct 8;23(27):9254-62
references.pmid: 14534260
references.citation: Dev Dyn. 1992 Feb;193(2):152-63
references.pmid: 1581603
references.citation: J Biol Chem. 1995 Jun 23;270(25):14913-8
references.pmid: 7797470
references.citation: Cell Tissue Res. 1996 Jun;284(3):355-65
references.pmid: 8646755
references.citation: Brain Res. 1980 Jun 16;192(1):17-28
references.pmid: 6103738
references.citation: Neuroscience. 1996 Jun;72(3):743-55
references.pmid: 9157320
references.citation: Mol Biol Cell. 2001 Apr;12(4):981-95
references.pmid: 11294901
references.citation: J Neurochem. 1983 Oct;41(4):1150-7
references.pmid: 6311978
references.citation: Brain Res Dev Brain Res. 1999 May 14;114(2):161-9
references.pmid: 10320755
references.citation: Methods Mol Med. 2003;89:161-75
references.pmid: 12958419
references.citation: Brain Res Dev Brain Res. 1999 Mar 12;113(1-2):47-54
references.pmid: 10064873
references.citation: Arterioscler Thromb Vasc Biol. 2003 Jul 1;23(7):1161-8
references.pmid: 12689915
references.citation: Neurochem Res. 2002 Feb;27(1-2):89-96
references.pmid: 11926280
references.citation: J Cereb Blood Flow Metab. 1986 Jun;6(3):305-14
references.pmid: 3711158
references.citation: J Histochem Cytochem. 1999 Aug;47(8):1021-30
references.pmid: 10424886
references.citation: J Physiol. 2001 Mar 15;531(Pt 3):585-95
references.pmid: 11251042
references.citation: Acta Neuropathol. 2001 Sep;102(3):278-84
references.pmid: 11585253
references.citation: Proc Natl Acad Sci U S A. 1996 Nov 12;93(23):13367-70
references.pmid: 8917597
references.citation: Proc Natl Acad Sci U S A. 1998 Sep 29;95(20):11981-6
references.pmid: 9751776
references.citation: Endocrinology. 1993 Feb;132(2):558-65
references.pmid: 8093876
references.citation: J Physiol. 1973 Sep;233(3):529-51
references.pmid: 4754872
references.citation: Thromb Res. 2000 May 1;98(3):73-81
references.pmid: 10812160
references.citation: Glia. 2003 May;42(3):235-51
references.pmid: 12673830
references.citation: Hypertens Res. 2003 Jan;26(1):67-73
references.pmid: 12661915
references.citation: J Neurotrauma. 1996 Sep;13(9):523-36
references.pmid: 8913969
references.citation: J Neurosci Res. 1989 Apr;22(4):464-72
references.pmid: 2668543
references.citation: J Mol Neurosci. 2001 Apr-Jun;16(2-3):181-93; discussion 215-21
references.pmid: 11478373
references.citation: Brain Res. 2000 Dec 8;885(2):251-61
references.pmid: 11102579
references.citation: Eur J Biochem. 1994 Feb 1;219(3):713-25
references.pmid: 8112322
references.citation: Biochem J. 1994 Jul 1;301 ( Pt 1):177-82
references.pmid: 8037667
references.citation: J Neurochem. 2003 Nov;87(4):891-901
references.pmid: 14622120
references.citation: FEBS Lett. 1997 Aug 11;413(1):152-6
references.pmid: 9287134
references.citation: Proc Natl Acad Sci U S A. 1989 Nov;86(21):8397-401
references.pmid: 2813396
references.citation: Neurosurgery. 1990 Mar;26(3):409-20
references.pmid: 2320209
references.citation: Histochem Cell Biol. 2004 Mar;121(3):201-7
references.pmid: 14986005
references.citation: Adv Drug Deliv Rev. 1999 Apr 5;36(2-3):145-163
references.pmid: 10837713
references.citation: Lancet Neurol. 2002 Sep;1(5):306-15
references.pmid: 12849428
references.citation: Neurochem Int. 2001 May;38(6):519-27
references.pmid: 11248400
references.citation: Proc Natl Acad Sci U S A. 2003 Feb 18;100(4):2106-11
references.pmid: 12578959
references.citation: J Cell Biol. 2001 Apr 30;153(3):543-53
references.pmid: 11331305
references.citation: J Neuroimmunol. 2001 Mar 1;114(1-2):168-72
references.pmid: 11240028
references.citation: FASEB J. 2004 Mar;18(3):542-4
references.pmid: 14734638
references.citation: J Cereb Blood Flow Metab. 1986 Dec;6(6):708-16
references.pmid: 3793806
references.citation: Cell Tissue Res. 1999 Jan;295(1):77-88
references.pmid: 9931355
references.citation: Diabetologia. 2002 Mar;45(3):356-68
references.pmid: 11914741
references.citation: Biochim Biophys Acta. 1975 Mar 25;382(3):377-92
references.pmid: 1125240
references.citation: Diabetes. 2001 Jun;50(6):1244-52
references.pmid: 11375323
references.citation: J Neuropathol Exp Neurol. 1998 Jul;57(7):699-713
references.pmid: 9690674
references.citation: Proc Natl Acad Sci U S A. 1991 Jul 1;88(13):5779-83
references.pmid: 2062858
references.citation: Glia. 1998 Mar;22(3):272-81
references.pmid: 9482213
references.citation: Nat Rev Drug Discov. 2002 Feb;1(2):131-9
references.pmid: 12120094
references.citation: J Cereb Blood Flow Metab. 1994 Jan;14(1):106-12
references.pmid: 8263045
references.citation: Neuroscience. 2003;122(3):677-88
references.pmid: 14622911
references.citation: Biochem J. 1997 Sep 1;326 ( Pt 2):539-44
references.pmid: 9291129
references.citation: Brain Res. 1994 Nov 7;663(1):7-18
references.pmid: 7850472
references.citation: J Clin Invest. 1991 Nov;88(5):1553-8
references.pmid: 1939644
references.citation: Am J Hum Genet. 1998 Dec;63(6):1578-87
references.pmid: 9837809
references.citation: J Neurochem. 2002 Oct;83(2):381-9
references.pmid: 12423248
references.citation: J Cereb Blood Flow Metab. 1988 Apr;8(2):244-53
references.pmid: 3343297
references.citation: J Biol Chem. 1996 Jun 21;271(25):14740-6
references.pmid: 8663046
references.citation: Proc Natl Acad Sci U S A. 1990 Apr;87(8):3244-7
references.pmid: 2326282
references.citation: IUBMB Life. 2002 Sep;54(3):101-7
references.pmid: 12489636
references.citation: Am J Physiol. 1998 Jan;274(1):G10-20
references.pmid: 9458768
references.citation: Mol Cell Biol. 2001 Nov;21(22):7852-61
references.pmid: 11604519
references.citation: J Neurocytol. 1997 Mar;26(3):133-48
references.pmid: 9192282
references.citation: J Cereb Blood Flow Metab. 1984 Jun;4(2):241-9
references.pmid: 6725434
references.citation: Am J Physiol. 1995 May;268(5 Pt 1):C1077-89
references.pmid: 7539214
references.citation: J Histochem Cytochem. 1994 Nov;42(11):1493-7
references.pmid: 7930531
references.citation: J Histochem Cytochem. 1996 Jul;44(7):679-85
references.pmid: 8675989
references.citation: J Neurochem. 1997 Mar;68(3):1278-85
references.pmid: 9048775
references.citation: J Histochem Cytochem. 2000 Jun;48(6):859-65
references.pmid: 10820159
references.citation: Science. 1978 Oct 13;202(4364):225-7
references.pmid: 211586
references.citation: Neurosci Lett. 1980 Nov;20(2):125-9
references.pmid: 6108538
references.citation: J Cell Biol. 2003 May 12;161(3):459-60
references.pmid: 12743096
references.citation: Exp Brain Res. 2001 Feb;136(4):523-34
references.pmid: 11291733
references.citation: J Gen Physiol. 1993 Nov;102(5):897-906
references.pmid: 8301262
references.citation: J Neurocytol. 2001 Aug;30(8):705-16
references.pmid: 12118158
references.citation: J Neuropathol Exp Neurol. 2002 Aug;61(8):725-35
references.pmid: 12152787
references.citation: Pharm Res. 2000 Mar;17(3):266-74
references.pmid: 10801214
references.citation: J Neurooncol. 1985;3(3):211-6
references.pmid: 2932540
references.citation: Anat Embryol (Berl). 1999 Jun;199(6):509-17
references.pmid: 10350131
references.citation: Brain Res. 1996 Jan 15;706(2):313-7
references.pmid: 8822374
references.citation: Neuroscience. 2002;115(1):145-52
references.pmid: 12401329
references.citation: J Biol Chem. 1990 Oct 15;265(29):18035-40
references.pmid: 2211679
references.citation: J Neurocytol. 1999 Sep;28(9):711-9
references.pmid: 10859574
references.citation: Diabetes. 2004 Jan;53(1):41-52
references.pmid: 14693696
references.citation: Neuroreport. 2003 Nov 14;14(16):2041-6
references.pmid: 14600494
references.citation: J Biol Chem. 2002 Dec 13;277(50):47972-5
references.pmid: 12393900
references.citation: Cell Mol Neurobiol. 2000 Apr;20(2):165-81
references.pmid: 10696508
references.citation: J Neurochem. 2001 May;77(4):1157-67
references.pmid: 11359881
references.citation: Eur J Neurosci. 1999 Mar;11(3):935-45
references.pmid: 10103087
references.citation: J Cell Biol. 2003 May 12;161(3):653-60
references.pmid: 12743111
references.citation: FEBS Lett. 2000 Jan 28;466(2-3):219-24
references.pmid: 10682831
references.citation: Acta Neuropathol. 2004 Apr;107(4):311-8
references.pmid: 14735305
references.citation: J Neuropathol Exp Neurol. 2004 Jan;63(1):73-83
references.pmid: 14748563
references.citation: Invest Ophthalmol Vis Sci. 2000 Jun;41(7):1876-84
references.pmid: 10845612
references.citation: J Neurosci. 1997 Jan 1;17(1):171-80
references.pmid: 8987746
references.citation: J Cereb Blood Flow Metab. 1998 Jan;18(1):26-42
references.pmid: 9428303
references.citation: Histochem J. 2000 May;32(5):313-24
references.pmid: 10939519
references.citation: J Cereb Blood Flow Metab. 1993 Sep;13(5):841-54
references.pmid: 8360290
references.citation: J Cereb Blood Flow Metab. 2003 Apr;23(4):432-40
references.pmid: 12679720
references.citation: J Neurochem. 2002 Apr;81(1):203-6
references.pmid: 12067234
references.citation: J Biol Chem. 1995 Jun 23;270(25):14907-12
references.pmid: 7797469
references.citation: Biochem Biophys Res Commun. 2000 Apr 13;270(2):495-503
references.pmid: 10753653