Lat1 transporters expressed in blood brain barrier cells

Abstract

LAT1 is consistently expressed at high levels in brain microvessel endothelial cells. Disclosed herein are assays for determining whether a test material/molecule is a substrate for, and/or is actively transported by, the LAT1 transporter, and therefore a candidate substrate for crossing the blood brain barrier. The assays are useful in screening for therapeutic, cytotoxic or imaging compounds used in the treatment or diagnosis of neurological diseases.

1 .- 34 . (canceled) 
     
     
         35 . A method of screening an agent or imaging component for decreased side effects in the central nervous system (CNS), comprising:
 (a) providing
 (i) an agent having a pharmacological activity, wherein the pharmacological activity is useful for treating a disease present in a tissue other than the CNS, and the agent causes undesired side effects in the CNS if the agent enters the CNS; or 
 (ii) an imaging component useful for imaging a tissue other than the CNS, and the imaging component causes undesired side effects in the CNS if the imaging component enters the CNS; 
   (b) modifying the agent or imaging component;   (c) providing a cell expressing at least one LAT1 transporter protein that transports substrates across the blood brain barrier,   (d) contacting the cell with the modified agent or modified imaging component; and   (e) determining whether the modified agent or modified imaging component passes through the plasma membrane via the transporter protein with a lower V max  than the agent, a lower V max  indicating that the modification decreases the capacity of the modified agent or modified imaging component relative to the agent or imaging component to cross the blood brain barrier, thereby decreasing undesired side effects in the CNS.   
     
     
         36 . The method of  claim 35 , wherein the cell is transformed or injected with a nucleic acid encoding a transporter or the cell is a brain microvessel endothelial cell. 
     
     
         37 . The method of  claim 35 , wherein the modifying comprises linking the agent or imaging component to a conjugate moiety to form a conjugate.