ATP-binding cassette transporters in immortalised human brain microvascular endothelial cells in normal and hypoxic conditions

Lindner Christian, Sigrüner Alexander, Walther Franziska, Bogdahn Ulrich, Couraud, Schmitz Gert, Schlachetzki, Schlachetzki Felix

Description

Rapid reperfusion following ischemia is the most effective therapy in stroke therapy. However, the success may be compromised by ischemia & reperfusion (I/R) injury and at the human blood–brain barrier (BBB), therefore the effects on transendothelial transport are of special interest. Current studies suggest the ATP-binding cassette (ABC) transporters to be regulated upon ischemic stroke in a way that impedes the effects of drug therapy. The immortalised human brain microvascular endothelial cell line hCMEC/D3 provides most of the unique properties of the BBB with respect to transport and might be a reliable in vitro model to study transendothelial transport after I/R. Methods We exposed hCMEC/D3 cells to 24 hours of hypoxia alone and to hypoxia followed by 60 min of reoxygenisation as an in vitro model for I/R. Western blot showed mild upregulation of hypoxia inducible factor (HIF-1α) after hypoxia alone and RNA lysates were analysed with a well-established real-time RT-PCR-based TaqMan low-density array detecting 47 of 48 known human ABC transporters. Results No significant increases of ABC mRNA expression levels were detected neither in hypoxic nor in I/R samples. However, slight decrease of ABCC1 in hypoxic and I/R samples and of ABCA10 and ABCD3 in I/R samples was observed. Conclusion Our data suggests that hCMEC/D3 cell line and – at the moment – in vitro models in general are a poor basis for stroke research but may be enhanced by co-culturing more cells of the neurovascular unit inducing an overall ischemic response at the BBB.

Sujets

• Blood-brain barrier
• Hypoxia-inducible factors
• Multiple drug resistance
• ATP-binding cassette transporter
• Stroke

Informations

• Publié par: biomed
• Publié le: 01 janvier 2012
• Nombre de lectures: 13
• Langue: English

Extrait

Lindneret al. Experimental & Translational Stroke Medicine2012,4:9 http://www.etsmjournal.com/content/4/1/9

R E S E A R C HOpen Access ATPbinding cassette transporters in immortalised human brain microvascular endothelial cells in normal and hypoxic conditions 1,2 31 14 Christian Lindner, Alexander Sigrüner , Franziska Walther , Ulrich Bogdahn , Pierre O Couraud , 3 1* Gert Schmitzand Felix Schlachetzki

Abstract Background:Rapid reperfusion following ischemia is the most effective therapy in stroke therapy. However, the success may be compromised by ischemia & reperfusion (I/R) injury and at the human blood–brain barrier (BBB), therefore the effects on transendothelial transport are of special interest. Current studies suggest the ATPbinding cassette (ABC) transporters to be regulated upon ischemic stroke in a way that impedes the effects of drug therapy. The immortalised human brain microvascular endothelial cell line hCMEC/D3 provides most of the unique properties of the BBB with respect to transport and might be a reliable in vitro model to study transendothelial transport after I/R. Methods:We exposed hCMEC/D3 cells to 24 hours of hypoxia alone and to hypoxia followed by 60 min of reoxygenisation as an in vitro model for I/R. Western blot showed mild upregulation of hypoxia inducible factor (HIF1α) after hypoxia alone and RNA lysates were analysed with a wellestablished realtime RTPCRbased TaqMan lowdensity array detecting 47 of 48 known human ABC transporters. Results:No significant increases of ABC mRNA expression levels were detected neither in hypoxic nor in I/R samples. However, slight decrease of ABCC1 in hypoxic and I/R samples and of ABCA10 and ABCD3 in I/R samples was observed. Conclusion:Our data suggests that hCMEC/D3 cell line and–at the moment–in vitro models in general are a poor basis for stroke research but may be enhanced by coculturing more cells of the neurovascular unit inducing an overall ischemic response at the BBB. Keywords:Blood–brain barrier, Ischemia/reperfusion injury, Hypoxiainducible factor, Multidrug resistance, ABC transporters, Stroke

Background The successful rescue of penumbral brain tissue by rapid reperfusion may be compromised by ischemia/reperfusion injury (I/R) and other secondary events, amongst them postischemic inflammatory response, excitotoxicity, excess of reactive oxygen species (ROS), and induction of apop totic neuronal cell death [13]. The cerebral endothelium, which forms the blood–brain barrier (BBB) invivo, may play a crucial role in postischemic reperfusion for several

* Correspondence: [e-mail]regensburg.de 1 Department of Neurology, University of Regensburg, Bezirksklinikum Regensburg, Regensburg, Germany Full list of author information is available at the end of the article

reasons: 1.) it is the primary site where reperfusion occurs, 2.) it allows interaction between the brain’s and body’s im mune system and, 3.) it strongly interacts with other cell types of the neurovascular unit via cellcell, cellmatrix and neuroendocrine cross talk, amongst others, determining the overall cerebral response to ischemia [46]. Several studies with I/R stroke models demonstrated a dynamic, even biphasic BBB permeability increase, whereas in clin ical stroke neurology only early postischemic BBB disrup tion has been associated with life threatening oedema formation and increased risk of symptomatic intracerebral hemorrhage [710]. However, other than BBB tight junction integrity several other BBB functions may be compromised

© 2012 Lindner et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.