title: Haploinsufficiency of the autism-associated Shank3 gene leads to deficits in synaptic function, social interaction, and social communication.
abstract: BACKGROUND
  SHANK3 is a protein in the core of the postsynaptic density (PSD) and has a critical role in recruiting many key functional elements to the PSD and to the synapse, including components of α-amino-3-hydroxyl-5-methyl-4-isoxazole-propionic acid (AMPA), metabotropic glutamate (mGlu) and N-methyl-D-aspartic acid (NMDA) glutamate receptors, as well as cytoskeletal elements. Loss of a functional copy of the SHANK3 gene leads to the neurobehavioral manifestations of 22q13 deletion syndrome and/or to autism spectrum disorders. The goal of this study was to examine the effects of haploinsufficiency of full-length Shank3 in mice, focusing on synaptic development, transmission and plasticity, as well as on social behaviors, as a model for understanding SHANK3 haploinsufficiency in humans.
  
  
  METHODS
  We used mice with a targeted disruption of Shank3 in which exons coding for the ankyrin repeat domain were deleted and expression of full-length Shank3 was disrupted. We studied synaptic transmission and plasticity by multiple methods, including patch-clamp whole cell recording, two-photon time-lapse imaging and extracellular recordings of field excitatory postsynaptic potentials. We also studied the density of GluR1-immunoreactive puncta in the CA1 stratum radiatum and carried out assessments of social behaviors.
  
  
  RESULTS
  In Shank3 heterozygous mice, there was reduced amplitude of miniature excitatory postsynaptic currents from hippocampal CA1 pyramidal neurons and the input-output (I/O) relationship at Schaffer collateral-CA1 synapses in acute hippocampal slices was significantly depressed; both of these findings indicate a reduction in basal neurotransmission. Studies with specific inhibitors demonstrated that the decrease in basal transmission reflected reduced AMPA receptor-mediated transmission. This was further supported by the observation of reduced numbers of GluR1-immunoreactive puncta in the stratum radiatum. Long-term potentiation (LTP), induced either with θ-burst pairing (TBP) or high-frequency stimulation, was impaired in Shank3 heterozygous mice, with no significant change in long-term depression (LTD). In concordance with the LTP results, persistent expansion of spines was observed in control mice after TBP-induced LTP; however, only transient spine expansion was observed in Shank3 heterozygous mice. Male Shank3 heterozygotes displayed less social sniffing and emitted fewer ultrasonic vocalizations during interactions with estrus female mice, as compared to wild-type littermate controls.
  
  
  CONCLUSIONS
  We documented specific deficits in synaptic function and plasticity, along with reduced reciprocal social interactions in Shank3 heterozygous mice. Our results are consistent with altered synaptic development and function in Shank3 haploinsufficiency, highlighting the importance of Shank3 in synaptic function and supporting a link between deficits in synapse function and neurodevelopmental disorders. The reduced glutamatergic transmission that we observed in the Shank3 heterozygous mice represents an interesting therapeutic target in Shank3-haploinsufficiency syndromes.
authors.affiliation: Seaver Autism Center for Research and Treatment, Mount Sinai School of Medicine, New York, NY 10029, USA.|Department of Psychiatry, Mount Sinai School of Medicine, New York, NY 10029, USA.
authors.forename: Ozlem
authors.initials: O
authors.lastname: Bozdagi
authors.affiliation: Seaver Autism Center for Research and Treatment, Mount Sinai School of Medicine, New York, NY 10029, USA.|Department of Psychiatry, Mount Sinai School of Medicine, New York, NY 10029, USA.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Sakurai
authors.affiliation: Department of Neuroscience, Mount Sinai School of Medicine, New York, NY 10029, USA.
authors.forename: Danae
authors.initials: D
authors.lastname: Papapetrou
authors.affiliation: Department of Neurology, Mount Sinai School of Medicine, New York, NY 10029, USA.
authors.forename: Xiaobin
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Neuroscience, Mount Sinai School of Medicine, New York, NY 10029, USA.
authors.forename: Dara L
authors.initials: DL
authors.lastname: Dickstein
authors.affiliation: Department of Psychiatry, Mount Sinai School of Medicine, New York, NY 10029, USA.
authors.forename: Nagahide
authors.initials: N
authors.lastname: Takahashi
authors.affiliation: Department of Psychiatry, Mount Sinai School of Medicine, New York, NY 10029, USA.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Kajiwara
authors.affiliation: Laboratory of Behavioral Neuroscience, National Institute of Mental Health, Bethesda, MD 20892-3730, USA.
authors.forename: Mu
authors.initials: M
authors.lastname: Yang
authors.affiliation: Laboratory of Behavioral Neuroscience, National Institute of Mental Health, Bethesda, MD 20892-3730, USA.
authors.forename: Adam M
authors.initials: AM
authors.lastname: Katz
authors.affiliation: Laboratory of Behavioral Neuroscience, National Institute of Mental Health, Bethesda, MD 20892-3730, USA.|Istituto Superiore di Sanità, Rome, Italy.
authors.forename: Maria Luisa
authors.initials: ML
authors.lastname: Scattoni
authors.affiliation: Laboratory of Behavioral Neuroscience, National Institute of Mental Health, Bethesda, MD 20892-3730, USA.
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Harris
authors.affiliation: Laboratory of Behavioral Neuroscience, National Institute of Mental Health, Bethesda, MD 20892-3730, USA.
authors.forename: Roheeni
authors.initials: R
authors.lastname: Saxena
authors.affiliation: Laboratory of Behavioral Neuroscience, National Institute of Mental Health, Bethesda, MD 20892-3730, USA.
authors.forename: Jill L
authors.initials: JL
authors.lastname: Silverman
authors.affiliation: Laboratory of Behavioral Neuroscience, National Institute of Mental Health, Bethesda, MD 20892-3730, USA.
authors.forename: Jacqueline N
authors.initials: JN
authors.lastname: Crawley
authors.affiliation: Department of Neurology, Mount Sinai School of Medicine, New York, NY 10029, USA.|Genentech, South San Francisco, CA 94080, USA.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Zhou
authors.affiliation: Department of Neuroscience, Mount Sinai School of Medicine, New York, NY 10029, USA.
authors.forename: Patrick R
authors.initials: PR
authors.lastname: Hof
authors.affiliation: Seaver Autism Center for Research and Treatment, Mount Sinai School of Medicine, New York, NY 10029, USA.|Department of Psychiatry, Mount Sinai School of Medicine, New York, NY 10029, USA.|Department of Neuroscience, Mount Sinai School of Medicine, New York, NY 10029, USA.|Department of Genetics and Genomic Sciences, Mount Sinai School of Medicine, New York, NY 10029, USA.
authors.forename: Joseph D
authors.initials: JD
authors.lastname: Buxbaum