title: The transporter and permeability interactions of asymmetric dimethylarginine (ADMA) and L-arginine with the human blood-brain barrier in vitro.
abstract: The blood-brain barrier (BBB) is a biological firewall that carefully regulates the cerebral microenvironment by acting as a physical, metabolic and transport barrier. This selectively permeable interface was modelled using the immortalised human cerebral microvascular endothelial cell line (hCMEC/D3) to investigate interactions with the cationic amino acid (CAA) L-arginine, the precursor for nitric oxide (NO), and with asymmetric dimethylarginine (ADMA), an endogenously derived analogue of L-arginine that potently inhibits NO production. The transport mechanisms utilised by L-arginine are known but they are not fully understood for ADMA, particularly at the BBB. This is of clinical significance giving the emerging role of ADMA in many brain and cerebrovascular diseases and its potential as a therapeutic target. We discovered that high concentrations of ADMA could induce endothelial dysfunction in the hCMEC/D3s BBB permeability model, leading to an increase in paracellular permeability to the paracellular marker FITC-dextran (40kDa). We also investigated interactions of ADMA with a variety of transport mechanisms, comparing the data with L-arginine interactions. Both molecules are able to utilise the CAA transport system y(+). Furthermore, the expression of CAT-1, the best known protein from this group, was confirmed in the hCMEC/D3s. It is likely that influx systems, such as y(+)L and b(0,+), have an important physiological role in ADMA transport at the BBB. These data are not only important with regards to the brain, but apply to other microvascular endothelia where ADMA is a major area of investigation.
authors.affiliation: King's College London, Institute of Pharmaceutical Science, Waterloo, London, UK.
authors.forename: Christopher P
authors.initials: CP
authors.lastname: Watson
authors.affiliation: Imperial College London, Experimental Medicine and Toxicology Section, Division of Experimental Medicine, London, UK.
authors.forename: Evangelos
authors.initials: E
authors.lastname: Pazarentzos
authors.affiliation: King's College London, Institute of Pharmaceutical Science, Waterloo, London, UK.
authors.forename: Mehmet
authors.initials: M
authors.lastname: Fidanboylu
authors.affiliation: King's College London, Institute of Pharmaceutical Science, Waterloo, London, UK.
authors.forename: Beatriz
authors.initials: B
authors.lastname: Padilla
authors.affiliation: King's College London, Institute of Pharmaceutical Science, Waterloo, London, UK.
authors.forename: Rachel
authors.initials: R
authors.lastname: Brown
authors.affiliation: King's College London, Institute of Pharmaceutical Science, Waterloo, London, UK. Electronic address: sarah.thomas@kcl.ac.uk.
authors.forename: Sarah A
authors.initials: SA
authors.lastname: Thomas
mesh_terms: D001120:Arginine / Q000031:analogs & derivatives* / Q000378:metabolism* / Q000494:pharmacology; D001812:Blood-Brain Barrier / Q000378:metabolism*; D027201:Cationic Amino Acid Transporter 1 / Q000378:metabolism*; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D007371:Interferon-gamma / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism*; D009952:Ornithine / Q000031:analogs & derivatives / Q000494:pharmacology; D010539:Permeability; D017382:Reactive Oxygen Species / Q000378:metabolism; D013395:Sucrose / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
chemical_list: D027201:Cationic Amino Acid Transporter 1; D004791:Enzyme Inhibitors; D017382:Reactive Oxygen Species; C420825:SLC7A1 protein, human; D014409:Tumor Necrosis Factor-alpha; D009569:Nitric Oxide; C065027:N(G)-iminoethylornithine; D013395:Sucrose; C018524:N,N-dimethylarginine; D007371:Interferon-gamma; D001120:Arginine; D009952:Ornithine
keywords: Cationic amino acid transporter 1; Cerebral microvasculature; Guanosine triphosphatases (GTPases); Nitric oxide