Calcyon upregulation in adolescence impairs response inhibition and working memory in adulthood

Abstract

Calcyon regulates activity dependent internalization of AMPA glutamate receptors and long term depression of excitatory synapses. Elevated levels of calcyon are consistently observed in brains from schizophrenic patients, and the calcyon gene is associated with attention deficit hyperactivity disorder. Executive function deficits are common to both disorders, and at least for schizophrenia, the etiology appears to involve both heritable and neurodevelopmental factors. Here, we show with calcyon overexpressing CalOE transgenic mice that lifelong calcyon upregulation impairs executive functions including response inhibition and working memory, without producing learning and memory deficits in general. As response inhibition and working memory, as well as the underlying neural circuitry continue to mature into early adulthood, we functionally silenced the transgene during postnatal days 28–49, a period corresponding to adolescence. Remarkably, the response inhibition and working memory deficits including perseverative behavior were absent in adult CalOE mice with the transgene silenced in adolescence. Suppressing the calcyon transgene in adulthood only partially rescued the deficits, suggesting calcyon upregulation in adolescence irreversibly alters development of neural circuits supporting mature response inhibition and working memory. Brain regional immunoblots revealed a prominent down-regulation of AMPA GluR1 subunits in hippocampus, and GluR2/3 subunits in hippocampus and prefrontal cortex of the CalOE mice. Silencing the transgene in adolescence prevented the decrease in hippocampal GluR1, further implicating altered frontohippocampal connectivity in the executive function deficits observed in the CalOE mice. Treatments that mitigate the effects of high levels of calcyon during adolescence could preempt adult deficits in executive functions in individuals at-risk for serious mental illness.

Exposure to variable prenatal stress in rats: Effects on anxiety-related behaviors, innate and contextual fear, and fear extinction

“…Interestingly, Koenig and colleagues found no evidence of impaired contextual fear extinction in either male or female rats, although this may be due to variations in the behavioral test protocol (e.g., combination of cued and context testing vs. context only) [31]. Extinction of fear is a learned inhibition of previous fear response in lieu of a new set of rules, and thus is thought to be a form of cognitive flexibility [17,53]. Consistent with this interpretation are results from one of our previous studies where variable PNS was associated with impaired cognitive flexibility (i.e., elevated timeout responses) in a 5-choice serial reaction time task [56].…”

Dynein binds and stimulates axonal motility of the endosome adaptor and NEEP21 family member, calcyon

“…E7-a) or anti-DIC antibodies followed by HRP conjugated secondary antibodies (1:20,000) (Jackson ImmunoResearch). For overlay assays with S-tagged hCaly (93-217)(Vazdarjanova et al, 2011), highly purified dynein complex was loaded on SDS-PAGE gels, and transferred to PVDF membrane, stained by SYPRO Ruby Protein Blot Stain reagent (S11791, ThermoFisher) to reveal dynein subunits, and then probed by 0.1mg/mL S-Caly. After washing in TBST, S-Caly binding was detected with 1:2,000 S-protein HRP conjugate (69047, Novagen).…”

“…Cargos sorted by NEEP21 and Caly range from GPCRs to ligand gated ion channels, and also include proteins such as neuregulin 1 and amyloid precursor protein which are prominent candidate genes in schizophrenia and Alzheimer’s Disease (Muthusamy et al, 2014; Norstrom et al, 2010; Yin et al, 2014). Manipulations that increase or eliminate NEEP21 or Caly expression result in ectopic cargo localization, as well as impaired synaptic plasticity and cognitive behavior (Alberi et al, 2005; Davidson et al, 2009; Debaigt et al, 2004; Vazdarjanova et al, 2011; Yap et al, 2008). When expression of NEEP21 is knocked down, GPCRs that are typically sorted to degradative pathways undergo recycling instead (Debaigt et al, 2004).…”

“…When expression of NEEP21 is knocked down, GPCRs that are typically sorted to degradative pathways undergo recycling instead (Debaigt et al, 2004). When Caly is upregulated, AMPA receptor subunits that are normally recycled to synapses, are instead degraded (Vazdarjanova et al, 2011). In contrast, levels of pre-synaptic cargoes like the zinc transporter 3 are reduced in axon terminals of Caly knockout mice (Muthusamy et al, 2012).…”

Calcyon Forms a Novel Ternary Complex with Dopamine D1 Receptor through PSD-95 Protein and Plays a Role in Dopamine Receptor Internalization

“…Recent studies, however, have introduced calcyon as a candidate gene for D 1 DR-related neurophysiological disorders. Calcyon levels were elevated in schizophrenia patients (4,5), whereas calcyon transgenic mice showed reduced anxiety and an impaired working memory (6,7). Calcyon was up-regulated in the rodent model of attention deficit hyperactivity disorder (8), and its gene variations are known to be associated with cocaine dependence (9).…”