Localization of brain endothelial luminal and abluminal transporters with immunogold electron microscopy.
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.
Cornford
Eain M
EM
Veterans Administration Greater Los Angeles Healthcare System, Los Angeles, California 90073, USA. cornford@ucla.edu
Hyman
Shigeyo
S
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
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
Acta Neuropathol. 1981;53(3):203-11
6111887
J Neurosci. 2003 Oct 8;23(27):9254-62
14534260
Dev Dyn. 1992 Feb;193(2):152-63
1581603
J Biol Chem. 1995 Jun 23;270(25):14913-8
7797470
Cell Tissue Res. 1996 Jun;284(3):355-65
8646755
Brain Res. 1980 Jun 16;192(1):17-28
6103738
Neuroscience. 1996 Jun;72(3):743-55
9157320
Mol Biol Cell. 2001 Apr;12(4):981-95
11294901
J Neurochem. 1983 Oct;41(4):1150-7
6311978
Brain Res Dev Brain Res. 1999 May 14;114(2):161-9
10320755
Methods Mol Med. 2003;89:161-75
12958419
Brain Res Dev Brain Res. 1999 Mar 12;113(1-2):47-54
10064873
Arterioscler Thromb Vasc Biol. 2003 Jul 1;23(7):1161-8
12689915
Neurochem Res. 2002 Feb;27(1-2):89-96
11926280
J Cereb Blood Flow Metab. 1986 Jun;6(3):305-14
3711158
J Histochem Cytochem. 1999 Aug;47(8):1021-30
10424886
J Physiol. 2001 Mar 15;531(Pt 3):585-95
11251042
Acta Neuropathol. 2001 Sep;102(3):278-84
11585253
Proc Natl Acad Sci U S A. 1996 Nov 12;93(23):13367-70
8917597
Proc Natl Acad Sci U S A. 1998 Sep 29;95(20):11981-6
9751776
Endocrinology. 1993 Feb;132(2):558-65
8093876
J Physiol. 1973 Sep;233(3):529-51
4754872
Thromb Res. 2000 May 1;98(3):73-81
10812160
Glia. 2003 May;42(3):235-51
12673830
Hypertens Res. 2003 Jan;26(1):67-73
12661915
J Neurotrauma. 1996 Sep;13(9):523-36
8913969
J Neurosci Res. 1989 Apr;22(4):464-72
2668543
J Mol Neurosci. 2001 Apr-Jun;16(2-3):181-93; discussion 215-21
11478373
Brain Res. 2000 Dec 8;885(2):251-61
11102579
Eur J Biochem. 1994 Feb 1;219(3):713-25
8112322
Biochem J. 1994 Jul 1;301 ( Pt 1):177-82
8037667
J Neurochem. 2003 Nov;87(4):891-901
14622120
FEBS Lett. 1997 Aug 11;413(1):152-6
9287134
Proc Natl Acad Sci U S A. 1989 Nov;86(21):8397-401
2813396
Neurosurgery. 1990 Mar;26(3):409-20
2320209
Histochem Cell Biol. 2004 Mar;121(3):201-7
14986005
Adv Drug Deliv Rev. 1999 Apr 5;36(2-3):145-163
10837713
Lancet Neurol. 2002 Sep;1(5):306-15
12849428
Neurochem Int. 2001 May;38(6):519-27
11248400
Proc Natl Acad Sci U S A. 2003 Feb 18;100(4):2106-11
12578959
J Cell Biol. 2001 Apr 30;153(3):543-53
11331305
J Neuroimmunol. 2001 Mar 1;114(1-2):168-72
11240028
FASEB J. 2004 Mar;18(3):542-4
14734638
J Cereb Blood Flow Metab. 1986 Dec;6(6):708-16
3793806
Cell Tissue Res. 1999 Jan;295(1):77-88
9931355
Diabetologia. 2002 Mar;45(3):356-68
11914741
Biochim Biophys Acta. 1975 Mar 25;382(3):377-92
1125240
Diabetes. 2001 Jun;50(6):1244-52
11375323
J Neuropathol Exp Neurol. 1998 Jul;57(7):699-713
9690674
Proc Natl Acad Sci U S A. 1991 Jul 1;88(13):5779-83
2062858
Glia. 1998 Mar;22(3):272-81
9482213
Nat Rev Drug Discov. 2002 Feb;1(2):131-9
12120094
J Cereb Blood Flow Metab. 1994 Jan;14(1):106-12
8263045
Neuroscience. 2003;122(3):677-88
14622911
Biochem J. 1997 Sep 1;326 ( Pt 2):539-44
9291129
Brain Res. 1994 Nov 7;663(1):7-18
7850472
J Clin Invest. 1991 Nov;88(5):1553-8
1939644
Am J Hum Genet. 1998 Dec;63(6):1578-87
9837809
J Neurochem. 2002 Oct;83(2):381-9
12423248
J Cereb Blood Flow Metab. 1988 Apr;8(2):244-53
3343297
J Biol Chem. 1996 Jun 21;271(25):14740-6
8663046
Proc Natl Acad Sci U S A. 1990 Apr;87(8):3244-7
2326282
IUBMB Life. 2002 Sep;54(3):101-7
12489636
Am J Physiol. 1998 Jan;274(1):G10-20
9458768
Mol Cell Biol. 2001 Nov;21(22):7852-61
11604519
J Neurocytol. 1997 Mar;26(3):133-48
9192282
J Cereb Blood Flow Metab. 1984 Jun;4(2):241-9
6725434
Am J Physiol. 1995 May;268(5 Pt 1):C1077-89
7539214
J Histochem Cytochem. 1994 Nov;42(11):1493-7
7930531
J Histochem Cytochem. 1996 Jul;44(7):679-85
8675989
J Neurochem. 1997 Mar;68(3):1278-85
9048775
J Histochem Cytochem. 2000 Jun;48(6):859-65
10820159
Science. 1978 Oct 13;202(4364):225-7
211586
Neurosci Lett. 1980 Nov;20(2):125-9
6108538
J Cell Biol. 2003 May 12;161(3):459-60
12743096
Exp Brain Res. 2001 Feb;136(4):523-34
11291733
J Gen Physiol. 1993 Nov;102(5):897-906
8301262
J Neurocytol. 2001 Aug;30(8):705-16
12118158
J Neuropathol Exp Neurol. 2002 Aug;61(8):725-35
12152787
Pharm Res. 2000 Mar;17(3):266-74
10801214
J Neurooncol. 1985;3(3):211-6
2932540
Anat Embryol (Berl). 1999 Jun;199(6):509-17
10350131
Brain Res. 1996 Jan 15;706(2):313-7
8822374
Neuroscience. 2002;115(1):145-52
12401329
J Biol Chem. 1990 Oct 15;265(29):18035-40
2211679
J Neurocytol. 1999 Sep;28(9):711-9
10859574
Diabetes. 2004 Jan;53(1):41-52
14693696
Neuroreport. 2003 Nov 14;14(16):2041-6
14600494
J Biol Chem. 2002 Dec 13;277(50):47972-5
12393900
Cell Mol Neurobiol. 2000 Apr;20(2):165-81
10696508
J Neurochem. 2001 May;77(4):1157-67
11359881
Eur J Neurosci. 1999 Mar;11(3):935-45
10103087
J Cell Biol. 2003 May 12;161(3):653-60
12743111
FEBS Lett. 2000 Jan 28;466(2-3):219-24
10682831
Acta Neuropathol. 2004 Apr;107(4):311-8
14735305
J Neuropathol Exp Neurol. 2004 Jan;63(1):73-83
14748563
Invest Ophthalmol Vis Sci. 2000 Jun;41(7):1876-84
10845612
J Neurosci. 1997 Jan 1;17(1):171-80
8987746
J Cereb Blood Flow Metab. 1998 Jan;18(1):26-42
9428303
Histochem J. 2000 May;32(5):313-24
10939519
J Cereb Blood Flow Metab. 1993 Sep;13(5):841-54
8360290
J Cereb Blood Flow Metab. 2003 Apr;23(4):432-40
12679720
J Neurochem. 2002 Apr;81(1):203-6
12067234
J Biol Chem. 1995 Jun 23;270(25):14907-12
7797469
Biochem Biophys Res Commun. 2000 Apr 13;270(2):495-503
10753653