Peripheral site acetylcholinesterase blockade induces RACK1-associated neuronal remodeling.
BACKGROUND
Peripheral anionic site (PAS) blockade of acetylcholinesterase (AChE) notably affects neuronal activity and cyto-architecture, however, the mechanism(s) involved are incompletely understood.


OBJECTIVE
We wished to specify the PAS extracellular effects on specific AChE mRNA splice variants, delineate the consequent cellular remodeling events, and explore the inhibitory effects on interchanging RACK1 interactions.


METHODS
We exposed rat hippocampal cultured neurons to BW284C51, the peripheral anionic site inhibitor of AChE, and to the non-selective AChE active site inhibitor, physostigmine for studying the neuronal remodeling of AChE mRNA expression and trafficking.


RESULTS
BW284C51 induced overexpression of both AChE splice variants, yet promoted neuritic translocation of the normally rare AChE-R, and retraction of AChE-S mRNA in an antisense-suppressible manner. BW284C51 further caused modest decreases in the expression of the scaffold protein RACK1 (receptor for activated protein kinase betaII), followed by drastic neurite retraction of both RACK1 and the AChE homologue neuroligin1, but not the tubulin-associated MAP2 protein. Accompanying BW284C51 effects involved decreases in the Fyn kinase and membrane insertion of the glutamate receptor NR2B variant and impaired glutamatergic activities of treated cells. Intriguingly, molecular modeling suggested that direct, non-catalytic competition with Fyn binding by the RACK1-interacting AChE-R variant may be involved.


CONCLUSIONS
Our findings highlight complex neuronal AChE-R/RACK1 interactions and are compatible with the hypothesis that peripheral site AChE inhibitors induce RACK1-mediated neuronal remodeling, promoting suppressed glutamatergic neurotransmission.
Farchi
Noa
N
Department of Neurobiology, Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel.
Ofek
Keren
K
Podoly
Erez
E
Dong
Haiheng
H
Xiang
Yun-Yan
YY
Diamant
Sophia
S
Livnah
Oded
O
Li
Jingxin
J
Hochner
Binyamin
B
Lu
Wei-Yang
WY
Soreq
Hermona
H
D000110:Acetylcholinesterase / Q000235:genetics / Q000378:metabolism*; D017398:Alternative Splicing; D000818:Animals; D002093:Benzenaminium, 4,4'-(3-oxo-1,5-pentanediyl)bis(N,N-dimethyl-N-2-propenyl-), Dibromide / Q000494:pharmacology; D002478:Cells, Cultured; D002800:Cholinesterase Inhibitors / Q000494:pharmacology; D006224:Cricetinae; D003412:Cricetulus; D004622:Embryo, Mammalian; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D006624:Hippocampus / Q000166:cytology; D008958:Models, Molecular; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D018408:Patch-Clamp Techniques / Q000379:methods; D010830:Physostigmine / Q000494:pharmacology; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D000075370:Receptors for Activated C Kinase; D011956:Receptors, Cell Surface / Q000378:metabolism*; D017470:Receptors, Glutamate / Q000187:drug effects / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods
D002800:Cholinesterase Inhibitors; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger; D000075370:Receptors for Activated C Kinase; D011956:Receptors, Cell Surface; D017470:Receptors, Glutamate; D002093:Benzenaminium, 4,4'-(3-oxo-1,5-pentanediyl)bis(N,N-dimethyl-N-2-propenyl-), Dibromide; D010830:Physostigmine; D000110:Acetylcholinesterase