Autism-associated SHANK3 haploinsufficiency causes I-h channelopathy in human neurons

摘要

Heterozygous SHANK3 mutations are associated with idiopathic autism and Phelan-McDermid syndrome. SHANK3 is a ubiquitously expressed scaffolding protein that is enriched in postsynaptic excitatory synapses. Here, we used engineered conditional mutations in human neurons and found that heterozygous and homozygous SHANK3 mutations severely and specifically impaired hyperpolarization-activated cation (I-h) channels. SHANK3 mutations caused alterations in neuronal morphology and synaptic connectivity; chronic pharmacological blockage of I-h channels reproduced these phenotypes, suggesting that they may be secondary to I-h-channel impairment. Moreover, mouse Shank3-deficient neurons also exhibited severe decreases in I-h currents. SHANK3 protein interacted with hyperpolarization-activated cyclic nucleotide-gated channel proteins (HCN proteins) that form I-h channels, indicating that SHANK3 functions to organize HCN channels. Our data suggest that SHANK3 mutations predispose to autism, at least partially, by inducing an I-h channelopathy that may be amenable to pharmacological intervention.