De‐palmitoylation by N‐(tert‐Butyl) hydroxylamine inhibits AMPAR‐mediated synaptic transmission via affecting receptor distribution in postsynaptic densities

• Published in: CNS neuroscience & therapeutics 2019-02, Vol.25 (2), p.187-199
• Main Authors: Xia, Zhi‐Xuan, Shen, Zu‐Cheng, Zhang, Shao‐Qi, Wang, Ji, Nie, Tai‐Lei, Deng, Qiao, Chen, Jian‐Guo, Wang, Fang, Wu, Peng‐Fei
• Format: Article
• Language: English
• Subjects: AMPA receptor; Animals; Biotin; Biotin - metabolism; CACNG2 protein; Calcium channels (voltage-gated); Calcium Channels - drug effects; Calcium Channels - metabolism; Central nervous system; Data processing; Disks Large Homolog 4 Protein - drug effects; Disks Large Homolog 4 Protein - metabolism; Excitatory postsynaptic potentials; Excitatory Postsynaptic Potentials - drug effects; Glutamic acid receptors; Hippocampus; Hippocampus - drug effects; Hippocampus - metabolism; Hydroxylamine; Hydroxylamines - pharmacology; Immunoprecipitation; Kinases; Male; Mice; Mice, Inbred C57BL; N-Methyl-D-aspartic acid receptors; Neuronal ceroid lipofuscinosis; Neuronal Ceroid-Lipofuscinoses - drug therapy; N‐(tert‐Butyl) hydroxylamine; Original; Palmitates - metabolism; Palmitoylation; Patch-Clamp Techniques; Postsynaptic density; postsynaptic density protein 95; Postsynaptic density proteins; Protein kinase A; Proteins; Receptors, AMPA - antagonists & inhibitors; Receptors, AMPA - metabolism; stargazin; Synapses - drug effects; Synapses - metabolism; Synaptic transmission; Synaptic Transmission - drug effects; α-Amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptors
• ISSN: 1755-5930; 1755-5949
• DOI: 10.1111/cns.12996

Summary Aims Palmitoylation of α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazolepropionic acid receptors (AMPARs) subunits or their “scaffold” proteins produce opposite effects on AMPAR surface delivery. Considering AMPARs have long been identified as suitable drug targets for central nervous system (CNS) disorders, targeting palmitoylation signaling to regulate AMPAR function emerges as a novel therapeutic strategy. However, until now, much less is known about the effect of palmitoylation‐deficient state on AMPAR function. Herein, we set out to determine the effect of global de‐palmitoylation on AMPAR surface expression and its function, using a special chemical tool, N‐(tert‐Butyl) hydroxylamine (NtBuHA). Methods BS3 protein cross‐linking, Western blot, immunoprecipitation, patch clamp, and biotin switch assay. Results Bath application of NtBuHA (1.0 mM) reduced global palmitoylated proteins in the hippocampus of mice. Although NtBuHA (1.0 mM) did not affect the expression of ionotropic glutamate receptor subunits, it preferentially decreased the surface expression of AMPARs, not N‐methyl‐d‐aspartate receptors (NMDARs). Notably, NtBuHA (1.0 mM) reduces AMPAR‐mediated excitatory postsynaptic currents (mEPSCs) in the hippocampus. This effect may be largely due to the de‐palmitoylation of postsynaptic density protein 95 (PSD95) and protein kinase A‐anchoring proteins, both of which stabilized AMPAR synaptic delivery. Furthermore, we found that changing PSD95 palmitoylation by NtBuHA altered the association of PSD95 with stargazin, which interacted directly with AMPARs, but not NMDARs. Conclusion Our data suggest that the palmitoylation‐deficient state initiated by NtBuHA preferentially reduces AMPAR function, which may potentially be used for the treatment of CNS disorders, especially infantile neuronal ceroid lipofuscinosis (Batten disease).