ABSTRACT: We report age-differential synaptic plasticity deficits associated with cognitive inflexibility and CaMKIIa hyperactivity in Adnp-mutant mice. These mice show impaired and inflexible contextual learning and memory along with social and anxiety-related deficits in adults, long after the juvenile-stage decrease of ADNP protein levels to ~10% of the newborn level. Adnp-mutant mice show abnormally enhanced long-term potentiation in adults but not in juveniles. This is accompanied by CaMKIIa hyperactivity involving increased baseline autophosphorylation and altered phosphorylation of CaMKIIa substrates, as revealed by unbiased proteomic analyses.
Project description:Autism spectrum disorders (ASD) represent neurodevelopmental disorders characterized by social deficits, repetitive behaviors, and various comorbidities, including epilepsy. ANK2, which encodes a neuronal scaffolding protein, is frequently mutated in ASD, but its in vivo functions and disease-related mechanisms are largely unknown. Here, we report that mice with Ank2 knockout restricted to cortical and hippocampal excitatory neurons (Ank2-cKO mice) show ASD-related behavioral abnormalities and juvenile seizure-related death. Ank2-cKO cortical neurons show abnormally increased excitability and firing rate. These changes accompanied decreases in the total level and function of the Kv7.2/KCNQ2 and Kv7.3/KCNQ3 potassium channels and the density of these channels in the enlengthened axon initial segment. Importantly, the Kv7 agonist, retigabine, rescued neuronal excitability, juvenile seizure-related death, and hyperactivity in Ank2-cKO mice. These results suggest that Ank2 regulates neuronal excitability by regulating the length of and Kv7 density in the AIS and that Kv7 channelopathy is involved in Ank2-related brain dysfunctions.
Project description:Dyrk1A deficiency is linked to various neurodevelopmental disorders, including developmental delays and autism spectrum disorders (ASD). Haploinsufficiency of Dyrk1a in mice leads to ASD-related phenotypes, although key pathological mechanisms remain unclear. In addition, human DYRK1A mutations have not been characterized in mice. Here we report Dyrk1a-knockin mice carrying a human mutation (Ile48LysfsX2; Dyrk1a-I48K mice). These mice display severe microcephaly, social and cognitive deficits, dendritic shrinkage, excitatory synaptic deficits, and altered phospho-proteome patterns enriched for multiple signaling pathways and synaptic proteins. Early chronic lithium treatment of newborn mutant mice rescues brain volume, behavior, dendrite, synapse, and signaling/synapse phospho-proteome phenotypes at juvenile and adult stages. These results suggest that signaling/synaptic alterations contribute to phenotypic alterations in Dyrk1a-I48K mice, and that early correction of these alterations by lithium treatment has long-lasting effects of preventing juvenile and adult-stage phenotypes.
Project description:We report age-differential synaptic plasticity deficits associated with cognitive inflexibility and CaMKIIa hyperactivity in Adnp-mutant mice. These mice show impaired and inflexible contextual learning and memory additional to social and anxiety-related deficits in adults long after a marked decrease in ADNP protein levels to ~10% of newborn levels in juveniles. In addition, Adnp-mutant adults show abnormally enhanced long-term potentiation in adults but not in juveniles. This accompanies CaMKIIa hyperactivity involving increased baseline autophosphorylation, as revealed by unbiased proteomic analyses.
Project description:ADNP syndrome, involving the ADNP transcription factor in the SWI/SNF chromatin-remodeling complex, is characterized by developmental delay, intellectual disability, and autism spectrum disorders (ASD). In ASD, ADNP is a highly penetrant risk gene, accounting for ~0.17% cases. Although Adnp-haploinsufficient mice display various phenotypic deficits, the underlying synaptic mechanisms are poorly understood. Here we report age-differential synaptic plasticity deficits associated with cognitive inflexibility and CaMKIIα hyperactivity in Adnp-mutant mice. These mice show impaired and inflexible contextual learning and memory additional to social and anxiety-related deficits in adults long after a marked decrease in ADNP protein levels to ~10% of newborn levels in juveniles. In addition, Adnp-mutant adults show abnormally enhanced long-term potentiation in adults but not in juveniles. This accompanies CaMKIIα hyperactivity involving increased baseline autophosphorylation, as revealed by unbiased proteomic analyses. Therefore, ADNP haploinsufficiency in mice leads to cognitive inflexibility involving altered synaptic plasticity and signaling in adults long after a marked decrease in Adnp expression in juveniles.
Project description:Dyrk1A deficiency is linked to various neurodevelopmental disorders, including developmental delays and autism spectrum disorders (ASD). Haploinsufficiency of Dyrk1a in mice leads to ASD-related phenotypes, although key pathological mechanisms remain unclear. In addition, human DYRK1A mutations have not been characterized in mice. Here we report Dyrk1a-knockin mice carrying a human mutation (Ile48LysfsX2; Dyrk1a-I48K mice). These mice display severe microcephaly, social and cognitive deficits, dendritic shrinkage, excitatory synaptic deficits, and altered phospho-proteome patterns enriched for multiple signaling pathways and synaptic proteins. Early chronic lithium treatment of newborn mutant mice rescues brain volume, behavior, dendrite, synapse, and signaling/synapse phospho-proteome phenotypes at juvenile and adult stages. These results suggest that signaling/synaptic alterations contribute to phenotypic alterations in Dyrk1a-I48K mice, and that early correction of these alterations by lithium treatment has long-lasting effects of preventing juvenile and adult-stage phenotypes.
Project description:Acute cognitive impairment (i.e., delirium) is common in elderly emergency department patients and frequently results from infections that are unrelated to the central nervous system. Since activation of the peripheral innate immune system induces brain microglia to produce inflammatory cytokines that are responsible for behavioral deficits, we investigated if aging exacerbated neuroinflammation and sickness behavior after peripheral injection of lipopolysaccharide (LPS). Microarray analysis revealed a transcriptional profile indicating the presence of primed or activated microglia and increased inflammation in the aged brain. Furthermore, aged mice had a unique gene expression profile in the brain after an intraperitoneal injection of LPS, and the LPS-induced elevation in the brain inflammatory cytokines and oxidative stress was both exaggerated and prolonged compared with adults. Aged mice were anorectic longer and lost more weight than adults after peripheral LPS administration. Moreover, reductions in both locomotor and social behavior remained 24 h later in aged mice, when adults had fully recovered, and the exaggerated neuroinflammatory response in aged mice was not reliably paralleled by increased circulating cytokines in the periphery. Taken together these data establish that activation of the peripheral innate immune system leads to exacerbated neuroinflammation in the aged as compared with adult mice. This dysregulated link between the peripheral and central innate immune system is likely to be involved in the severe behavioral deficits that frequently occur in older adults with systemic infections. Experiment Overall Design: In this study, adult and aged mice were injected intraperitoneal with sterile saline or Escherichia coli LPS (0.33 mg/kg, ~10 µg/mouse; serotype 0127:B8, Sigma). This dosage of LPS was used because it induces a mild transient sickness behavior in young adults. Mice were killed 4 h after saline or LPS injection by CO2 asphyxiation. Blood samples were collected and brains were removed, separated in half at the longitudinal fissure, frozen in liquid nitrogen, and stored (-80°C) until assaying. Total RNA was later isolated from some brain samples for microarray analysis (n=3).
Project description:Despite the predominance and high heritability of Attention-Deficit/Hyperactivity Disorder (ADHD), its etiology remains elusive. Preclinical and clinical evidence partly points to impaired limbic system function, particularly that of the hippocampus (HPC). Children diagnosed with ADHD often struggle with deficits in executive function, temporal processing, and visuospatial memory, the defining hallmarks of the predominantly inattentive presentation (ADHD-PI), thought to be subserved by the HPC brain region. However, the specific genes/proteins involved and how they shape the hippocampal makeup to influence ADHD behavior are poorly understood. As an exploratory tool, hippocampal tissues from a mouse model overexpressing thyroid hormone-responsive protein (THRSP), with defining characteristics of ADHD-PI presentation, were utilized for proteomic analyses. Results revealed differential expressions of proteins involved in Wnt signaling. Compared to THRSP knockout (KO), THRSP OE mice have impaired attention and memory concomitant to dysregulated Wnt signaling affecting hippocampal cell proliferation (BrdU) and neurogenic markers expressions (i.e., NEU-N, GFAP), markers of neural stem cell (NSC) activity. Also, exposure to a combination of enriched environment and treadmill exercise improves behavioral deficits in THRSP OE mice and improves Wnt signaling and NSC activity.
Project description:Auxilin participates in the uncoating of clathrin-coated vesicles (CCVs), thereby facilitating synaptic vesicle (SV) regeneration at presynaptic sites. Auxilin (DNAJC6/PARK19) loss-of-function mutations cause early-onset Parkinson’s disease (PD). Here, we utilized auxilin-knockout (KO) mice to elucidate the mechanisms through which auxilin deficiency and clathrin-uncoating deficits lead to PD. Auxilin KO mice display cardinal features of PD, including progressive motor deficits, α-synuclein pathology, nigral dopaminergic loss, and neuroinflammation. Significantly, treatment with L-DOPA ameliorated motor deficits. Unbiased proteomic and neurochemical analyses of auxilin KO brains indicated dopamine dys-homeostasis. We validated these findings by demonstrating slower dopamine reuptake kinetics in vivo, an effect associated with dopamine transporter misrouting into axonal membrane deformities in the dorsal striatum. Defective SV protein sorting and elevated synaptic autophagy also contribute to ineffective dopamine sequestration and compartmentalization, ultimately leading to neurodegeneration. This study advances our knowledge of how presynaptic endocytosis deficits lead to dopaminergic vulnerability and pathogenesis of PD.
Project description:, this study aimed to investigate the mechanisms underlying neuropathological processes related to cognitive impairment in mice chronically-treated with METH. In addition, the effective melatonin on recovery of neurological dysfunction and neurobehavioral deficits during METH withdrawal was also investigated. Cognitive function was evaluated in mice after chronic METH administration and METH withdrawal, and the effect of melatonin treatment during the withdrawal phase on cognitive function was also assessed. In addition, the profile of proteins related to mitochondrial and neurological functions in PFC was determined using proteomic and western blot analysis.
Project description:The study aims at illustrate novel role of TWEAK/Fn14 signaling in synapse function by combining electrophysiological and phosphoproteomic approaches. The results show that TWEAK acutely dampens basal synaptic transmission and plasticity through neuronal Fn14 and impacts the phosphorylation state of pre- and post-synaptic proteins in adult mouse hippocampal slices. Two models featuring synaptic deficits were used in the study. Blocking TWEAK/Fn14 signaling augments synaptic function in hippocampal slices from amyloid beta-overexpressing mice. After stroke, genetic or pharmacological inhibition of TWEAK/Fn14 signaling augments basal synaptic transmission and normalizes plasticity. Our data support a glial/neuronal axis that critically modifies synaptic physiology and pathophysiology in different contexts in the mature brain and may be a therapeutic target for improving neurophysiological outcomes.