Identification and characterization of RNA aptamers: A long aptamer blocks the AMPA receptor and a short aptamer blocks both AMPA and kainate receptors.
AMPA and kainate receptors, along with NMDA receptors, represent different subtypes of glutamate ion channels. AMPA and kainate receptors share a high degree of sequence and structural similarities, and excessive activity of these receptors has been implicated in neurological diseases such as epilepsy. Therefore, blocking detrimental activity of both receptor types could be therapeutically beneficial. Here, we report the use of anin vitroevolution approach involving systematic evolution of ligands by exponential enrichment with a single AMPA receptor target (i.e.GluA1/2R) to isolate RNA aptamers that can potentially inhibit both AMPA and kainate receptors. A full-length or 101-nucleotide (nt) aptamer selectively inhibited GluA1/2R with aKIof ∼5 μm, along with GluA1 and GluA2 AMPA receptor subunits. Of note, its shorter version (55 nt) inhibited both AMPA and kainate receptors. In particular, this shorter aptamer blocked equally potently the activity of both the GluK1 and GluK2 kainate receptors. Using homologous binding and whole-cell recording assays, we found that an RNA aptamer most likely binds to the receptor's regulatory site and inhibits it noncompetitively. Our results suggest the potential of using a single receptor target to develop RNA aptamers with dual activity for effectively blocking both AMPA and kainate receptors.
From the Department of Chemistry and Center for Neuroscience Research, University at Albany, SUNY, Albany, New York 12222.
William J
WJ
Jaremko
From the Department of Chemistry and Center for Neuroscience Research, University at Albany, SUNY, Albany, New York 12222.
Zhen
Z
Huang
From the Department of Chemistry and Center for Neuroscience Research, University at Albany, SUNY, Albany, New York 12222.
Wei
W
Wen
From the Department of Chemistry and Center for Neuroscience Research, University at Albany, SUNY, Albany, New York 12222.
Andrew
A
Wu
From the Department of Chemistry and Center for Neuroscience Research, University at Albany, SUNY, Albany, New York 12222.
Nicholas
N
Karl
From the Department of Chemistry and Center for Neuroscience Research, University at Albany, SUNY, Albany, New York 12222 lniu@albany.edu.
Li
L
Niu
D000818:Animals; D052157:Aptamers, Nucleotide / Q000737:chemistry* / Q000494:pharmacology*; D002460:Cell Line; D051381:Rats; D018091:Receptors, AMPA / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism; D018092:Kainic Acid Receptors / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism; D000097806:GluK2 Kainate Receptor
D052157:Aptamers, Nucleotide; D018091:Receptors, AMPA; D018092:Kainic Acid Receptors; D000097806:GluK2 Kainate Receptor; C104722:glutamate receptor ionotropic, AMPA 2
RNA; RNA aptamers; SELEX; central nervous system (CNS); glutamate receptor; inhibitor; kainate receptor; α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPA receptor, AMPAR)