1. A mouse model of autism implicates endosome pH in the regulation of presynaptic calcium entry.
- Author
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Ullman, Julie C, Yang, Jing, Sullivan, Michael, Bendor, Jacob, Levy, Jonathan, Pham, Ellen, Silm, Katlin, Seifikar, Helia, Sohal, Vikaas S, Nicoll, Roger A, and Edwards, Robert H
- Subjects
Hippocampus ,Neurons ,Presynaptic Terminals ,Synaptic Vesicles ,Endosomes ,Animals ,Mice ,Knockout ,Humans ,Mice ,Disease Models ,Animal ,Calcium ,Glutamic Acid ,Electroencephalography ,Behavior ,Animal ,Attention Deficit Disorder with Hyperactivity ,Synaptic Transmission ,Gene Expression ,Hydrogen-Ion Concentration ,Female ,Male ,Primary Cell Culture ,Autism Spectrum Disorder ,Sodium-Hydrogen Exchangers ,Behavior ,Animal ,Disease Models ,Knockout - Abstract
Psychoactive compounds such as chloroquine and amphetamine act by dissipating the pH gradient across intracellular membranes, but the physiological mechanisms that normally regulate organelle pH remain poorly understood. Interestingly, recent human genetic studies have implicated the endosomal Na+/H+ exchanger NHE9 in both autism spectrum disorders (ASD) and attention deficit hyperactivity disorder (ADHD). Plasma membrane NHEs regulate cytosolic pH, but the role of intracellular isoforms has remained unclear. We now find that inactivation of NHE9 in mice reproduces behavioral features of ASD including impaired social interaction, repetitive behaviors, and altered sensory processing. Physiological characterization reveals hyperacidic endosomes, a cell-autonomous defect in glutamate receptor expression and impaired neurotransmitter release due to a defect in presynaptic Ca2+ entry. Acute inhibition of synaptic vesicle acidification rescues release but without affecting the primary defect due to loss of NHE9.
- Published
- 2018