Document Detail


Rapid loss of blood-brain barrier P-glycoprotein activity through transporter internalization demonstrated using a novel in situ proteolysis protection assay.
MedLine Citation:
PMID:  20628400     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Blood-brain barrier (BBB) P-glycoprotein activity is rapidly reduced by vascular endothelial growth factor (VEGF) acting via Src and by tumor necrosis factor-alpha acting via protein kinase C (PKC)beta1. To probe underlying mechanism(s), we developed an in vivo, immunoblot-based proteinase K (PK) protection assay to assess the changes in the P-glycoprotein content of the BBB's luminal membrane. Infusion of PK into the brain vasculature selectively cleaved luminal membrane P-glycoprotein, leaving intracellular proteins intact. Intracerebroventricular injection of VEGF partially protected P-glycoprotein from proteolytic cleavage, consistent with transporter internalization. Activation of PKCbeta1 did not protect P-glycoprotein. Thus, VEGF and PKCbeta1 reduce P-glycoprotein activity by distinct mechanisms.
Authors:
Brian T Hawkins; Robert R Rigor; David S Miller
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Intramural     Date:  2010-07-14
Journal Detail:
Title:  Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism     Volume:  30     ISSN:  1559-7016     ISO Abbreviation:  J. Cereb. Blood Flow Metab.     Publication Date:  2010 Sep 
Date Detail:
Created Date:  2010-09-02     Completed Date:  2010-10-19     Revised Date:  2011-09-13    
Medline Journal Info:
Nlm Unique ID:  8112566     Medline TA:  J Cereb Blood Flow Metab     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1593-7     Citation Subset:  IM    
Affiliation:
Laboratory of Toxicology and Pharmacology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709, USA.
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MeSH Terms
Descriptor/Qualifier:
Animals
Blood-Brain Barrier / drug effects*,  metabolism*
Blotting, Western
Capillaries / drug effects
Cerebrovascular Circulation / drug effects
Endocytosis / drug effects
Endopeptidase K / pharmacology*
Enzyme Activation / drug effects
Injections, Intraventricular
Male
Membrane Proteins / metabolism
Neuroprotective Agents*
P-Glycoprotein / metabolism*
Phorbol Esters / pharmacology
Rats
Rats, Sprague-Dawley
Vascular Endothelial Growth Factor A / pharmacology
Chemical
Reg. No./Substance:
0/Membrane Proteins; 0/Neuroprotective Agents; 0/P-Glycoprotein; 0/Phorbol Esters; 0/Vascular Endothelial Growth Factor A; 54662-30-5/12-deoxyphorbolphenylacetate-20-acetate; EC 3.4.21.64/Endopeptidase K
Comments/Corrections

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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