Meeting Abstract
P2.118 Wednesday, Jan. 5 Manipulation of Alternative Splicing in Multiexon Genes: Altering the Kinetics of Synaptic Transmission by Hippocampal CA-1 Neurons COUGHLIN, D. J.*; LYKENS, N. M.; REDDI, J. M.; LUTZ, G. J.; TALLENT, M. K.; Widener Univ.; Drexel Univ.; Drexel Univ.; Drexel Univ.; Drexel Univ. djcoughlin@widener.edu
Multiexon genes in both vertebrates and invertebrates are predominantly alternatively spliced. Splice variants differ in both structure and function, altering animal physiology. Splice modulating oligonucleotides (SMOs) are a class of compounds that bind to and block pre-mRNA regulatory sites to direct alternative splicing. This study employed an SMO to direct alternative splicing of AMPA glutamate receptor GluR1. GluR genes are expressed as two alternative splice variants called ‘flip’ and ‘flop’, and AMPA receptor activity depends on the ratio of flip to flop expression. GluR1-flip has higher glutamate sensitivity than GluR1-flop, and higher GluR1-flip levels lead to neuronal network hyperexcitability. In humans, this hyperexcitability is associated with epilepsy. The goal of this work was to decrease GluR1 flip expression and thus reduce AMPA receptor activity. A GluR1-targeting SMO was injected in the cerebral ventricles of neonatal mice, leading to dramatic reduction in GluR1-flip levels in hippocampal CA1 neurons. Whole-cell patch clamp recordings in hippocampal slices from P10 mice showed that SMO-mediated decreases in GluR1 flip/flop ratios reduced AMPA glutamate receptor mediated excitatory post-synaptic currents (EPSCs) generated at Schaeffer collateral/CA1 synapses by about 40%, while NMDA glutamate receptor mediated EPSCs were unaffected. Further, these mice displayed seizure resistance but retained normal cellular mechanisms of memory. SMOs are powerful tools to investigate the role of the alternative splicing in hippocampal synaptic function in mice. SMOs may have broad applications as therapeutic agents and experimentally to examine structure and function relationships of alternatively spliced genes in in vivo or in situ environments.
