RNA aptamers selected against the GluR2 glutamate receptor channel.
The excessive activation of AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid) receptors, a subtype of glutamate ion channels, has been implicated in various neurological diseases such as cerebral ischemeia and amyotrophic lateral sclerosis. Inhibitors of AMPA receptors are drug candidates for potential treatment of these diseases. Using the systematic evolution of ligands by exponential enrichment (SELEX), we have selected a group of RNA aptamers against the recombinant GluR2Qflip AMPA receptor transiently expressed in HEK-293 (human embryonic kidney) cells. One of the aptamers, AN58, is shown to competitively inhibit the receptor. The nanomolar affinity of AN58 rivals that of NBQX (6-nitro-7-sulfamoyl-benzo[f]quinoxaline-2,3-dione), one of the best competitive inhibitors. Like NBQX, AN58 has the highest affinity for GluR2, the selection target, among all AMPA receptor subunits. However, AN58 has a higher selectivity for the GluR4 AMPA receptor subunit and remains potent even at pH = 6.8 (i.e., a clinically relevant acidic pH), as compared with NBQX. Furthermore, this RNA molecule possesses stable physical properties. Therefore, AN58 serves as a unique lead compound for developing water-soluble inhibitors with a nanomolar affinity for GluR2 AMPA receptors.
Huang
Zhen
Z
Department of Chemistry, Center for Neuroscience Research, University at Albany, State University of New York, Albany, New York 12222, USA.
Pei
Weimin
W
Jayaseelan
Sabarinath
S
Shi
Hua
H
Niu
Li
L
D000818:Animals; D000831:Animals, Newborn; D052157:Aptamers, Nucleotide / Q000138:chemical synthesis* / Q000302:isolation & purification* / Q000494:pharmacology; D001483:Base Sequence; D002478:Cells, Cultured; D006801:Humans; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D012313:RNA; D051381:Rats; D017207:Rats, Sprague-Dawley; D018091:Receptors, AMPA / Q000037:antagonists & inhibitors* / Q000235:genetics; D011994:Recombinant Proteins / Q000037:antagonists & inhibitors / Q000235:genetics; D052156:SELEX Aptamer Technique; D013379:Substrate Specificity; D014162:Transfection
D052157:Aptamers, Nucleotide; C496853:RNA aptamer 58; D018091:Receptors, AMPA; D011994:Recombinant Proteins; D012313:RNA; C104722:glutamate receptor ionotropic, AMPA 2