γ-Glutamyl Transpeptidase, a Blood-Brain Barrier Associated Membrane Protein

1997 ◽  
pp. 37-45 ◽  
Author(s):  
Sabine Wolf ◽  
H. G. Gassen
Keyword(s):  
Membrane Protein ◽  
Blood Brain Barrier ◽  
Brain Barrier ◽  
Blood Brain ◽  
Glutamyl Transpeptidase

Quantitative Membrane Protein Expression at the Blood–Brain Barrier of Adult and Younger Cynomolgus Monkeys

2011 ◽  
Vol 100 (9) ◽  
pp. 3939-3950 ◽  
Author(s):  
Katsuaki Ito ◽  
Yasuo Uchida ◽  
Sumio Ohtsuki ◽  
Sanshiro Aizawa ◽  
Hirotaka Kawakami ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Protein Expression ◽  
Blood Brain Barrier ◽  
Brain Barrier ◽  
Cynomolgus Monkeys ◽  
Membrane Protein Expression ◽  
Blood Brain

scholarly journals A yeast display immunoprecipitation screen for targeted discovery of antibodies against membrane protein complexes

2019 ◽  
Vol 32 (5) ◽  
pp. 219-230
Author(s):  
Jason M Lajoie ◽  
Yong Ku Cho ◽  
Dustin Frost ◽  
Samantha Bremner ◽  
Lingjun Li ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Blood Brain Barrier ◽  
Membrane Trafficking ◽  
Plasma Membranes ◽  
Protein Complexes ◽  
Brain Barrier ◽  
Yeast Display ◽  
Functional Protein ◽  
Blood Brain ◽  
Membrane Protein Complexes

Abstract Yeast display immunoprecipitation is a combinatorial library screening platform for the discovery and engineering of antibodies against membrane proteins using detergent-solubilized membrane fractions or cell lysates as antigen sources. Here, we present the extension of this method for the screening of antibodies that bind to membrane protein complexes, enabling discovery of antibodies that target antigens involved in a functional protein-protein interaction of interest. For this proof-of-concept study, we focused on the receptor-mediated endocytosis machinery at the blood-brain barrier, and adaptin 2 (AP-2) was chosen as the functional interaction hub. The goal of this study was to identify antibodies that bound to blood-brain barrier (BBB) membrane protein complexes containing AP-2. Screening of a nonimmune yeast display antibody library was carried out using detergent-solubilized BBB plasma membranes as an antigen pool, and antibodies that could interact with protein complexes containing AP-2 were identified. Downstream characterization of isolated antibodies confirmed targeting of proteins known to play important roles in membrane trafficking. This functional yeast display immunoprecipitation screen may be applied to other systems where antibodies against other functional classes of protein complexes are sought.

Intracarotid Infusion of Leukotriene C4 Selectively Increases Blood-Brain Barrier Permeability after Focal Ischemia in Rats

1991 ◽  
Vol 11 (4) ◽  
pp. 638-643 ◽  
Author(s):  
Takehiko Baba ◽  
Keith L. Black ◽  
Kiyonobu Ikezaki ◽  
Kangnian Chen ◽  
Donald P. Becker
Keyword(s):  
Blood Brain Barrier ◽  
Brain Barrier ◽  
Normal Brain ◽  
Brain Capillaries ◽  
Transfer Constant ◽  
Blood Brain ◽  
Mca Occlusion ◽  
Ischemic Tissue ◽  
Bbb Permeability ◽  
Glutamyl Transpeptidase

Intracarotid infusions of leukotriene C4 (LTC4) were used to open selectively the blood–brain barrier (BBB) in ischemic tissue after middle cerebral artery (MCA) occlusion in rats. BBB permeability was determined by quantitative autoradiography using [14C]aminoisobutyric acid. Seventy-two hours after MCA occlusion, LTC4 (4 μg total dose) infused into the carotid artery ipsilateral to the MCA occlusion selectively increased the unidirectional transfer constant for permeability K1 approximately threefold within core ischemic tissue and tissue adjacent to the ischemic core. No effect on BBB permeability was seen within nonischemic brain tissue or in ischemic tissue after only 24 h after MCA occlusion. γ-Glutamyl transpeptidase (γ-GTP) activity was decreased in capillaries in ischemic tissue at 48 and 72 h after infarction, compared to high γ-GTP in normal brain capillaries and moderate γ-GTP in capillaries in the ischemic tissue at 24 h after infarction. These findings suggest that normal brain capillaries resist the vasogenic effects of LTC4. In contrast, LTC4 increases permeability in capillaries of ischemic tissue, where γ-GTP is decreased. γ-Glutamyl transpeptidase, an enzyme that inactivates LTC4 to LTD4 and LTE4 to LTF4, may act as an “enzymatic barrier” in normal brain capillaries to leukotrienes.

scholarly journals Regulation of a Blood-Brain Barrier—Specific Enzyme Expressed by Cerebral Pericytes (Pericytic Aminopeptidase N/pAPN) under Cell Culture Conditions

1998 ◽  
Vol 18 (11) ◽  
pp. 1270-1281 ◽  
Author(s):  
Markus Ramsauer ◽  
Jörg Kunz ◽  
Dorothee Krause ◽  
Rolf Dermietzel
Keyword(s):  
Endothelial Cells ◽  
Blood Brain Barrier ◽  
Culture Conditions ◽  
Aminopeptidase N ◽  
Brain Barrier ◽  
Blood Brain ◽  
In Vitro Effects ◽  
Culturing Conditions ◽  
Glutamyl Transpeptidase

In this study we show that the aminopeptidase N of cerebral pericytes (pAPN) associated with the blood—brain barrier (BBB) is downregulated in pericytic cell cultures. This observation is in accordance with previous data describing comparable in vitro effects for BBB-specific enzymes of endothelial or pericytic origin, such as γ-glutamyl transpeptidase or alkaline phosphatase. By polymerase chain reaction and in situ hybridization we were able to determine that the downregulation of pAPN occurs at the posttranscriptional level. The mRNA of pAPN was found to be constitutively expressed even when the protein is no longer detectable. Culturing the pericytes in an endothelial cell—conditioned medium allowed pAPN to be reexpressed. However, the reexpression effect depended largely on the culturing conditions of the pericytes. Although purified pericytes deprived of endothelial cells did not reveal a reexpression effect, pericytes that were kept in contact with endothelial cells were able to acquire a pAPN-positive phenotype, indicating that endothelial cells constitute an essential requirement for the in vitro reexpression of pAPN. Astrocytes, however, were insufficient in exerting any reexpression effect.

scholarly journals The Epithelial Membrane Protein 1 is a Novel Tight Junction Protein of the Blood—Brain Barrier

2008 ◽  
Vol 28 (6) ◽  
pp. 1249-1260 ◽  
Author(s):  
Thorsten Bangsow ◽  
Ewa Baumann ◽  
Carmen Bangsow ◽  
Martina H Jaeger ◽  
Bernhard Pelzer ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Cerebral Ischemia ◽  
Membrane Protein ◽  
Rat Brain ◽  
Blood Brain Barrier ◽  
Differentially Expressed ◽  
Brain Barrier ◽  
Brain Vessels ◽  
Blood Brain ◽  
Junction Protein

In the central nervous system, a constant microenvironment required for neuronal cell activity is maintained by the blood—brain barrier (BBB). The BBB is formed by the brain microvascular endothelial cells (BMEC), which are sealed by tight junctions (TJ). To identify genes that are differentially expressed in BMEC compared with peripheral endothelial cells, we constructed a subtractive cDNA library from porcine BMEC (pBMEC) and aortic endothelial cells (AOEC). Screening the library for differentially expressed genes yielded 26 BMEC-specific transcripts, such as solute carrier family 35 member F2 (SLC35F2), ADP-ribosylation factor-like 5B (ARL5B), TSC22 domain family member 1 (TSC22D1), integral membrane protein 2A (ITM2A), and epithelial membrane protein 1 (EMP1). In this study, we show that EMP1 transcript is enriched in pBMEC compared with brain tissue and that EMP1 protein colocalizes with the TJ protein occludin in mouse BMEC by coimmunoprecipitation and in rat brain vessels by immunohistochemistry. Epithelial membrane protein 1 expression was transiently induced in laser-capture microdissected rat brain vessels after a 20-min global cerebral ischemia, in parallel with the loss of occludin immunoreactivity. The study identifies EMP1 as a novel TJ-associated protein of the BBB and suggests its potential role in the regulation of the BBB function in cerebral ischemia.

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