7 research outputs found

    The zinc transporter SLC39A7 (ZIP7) is essential for regulation of cytosolic zinc levels s

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    Zinc homeostasis is a highly regulated process in mammalian cells that is critical for normal growth and development. Movement of zinc across cell compartments is controlled by two classes of transporters: Slc39a family members transport zinc into the cytosol from either the extracellular space or intracellular stores such as the endoplasmic reticulum (ER), whereas the SLC30A family mediates zinc efflux from the cytosol. In this study, we report that genetic ablation of SLC39A7 (ZIP7) results in decreased cytosolic zinc levels, increased ER zinc levels, impaired cell prolif

    Engram-specific transcriptome profiling of contextual memory consolidation

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    Sparse populations of neurons in the dentate gyrus (DG) of the hippocampus are causally implicated in the encoding of contextual fear memories. However, engram-specific molecular mechanisms underlying memory consolidation remain largely unknown. Here we perform unbiased RNA sequencing of DG engram neurons 24 h after contextual fear conditioning to identify transcriptome changes specific to memory consolidation. DG engram neurons exhibit a highly distinct pattern of gene expression, in which CREB-dependent transcription features prominently (P = 6.2 × 10−13), including Atf3 (P = 2.4 × 10−41), Penk (P = 1.3 × 10−15), and Kcnq3 (P = 3.1 × 10−12). Moreover, we validate the functional relevance of the RNAseq findings by establishing the causal requirement of intact CREB function specifically within the DG engram during memory consolidation, and identify a novel group of CREB target genes involved in the encoding of long-term memory

    Candidate CSPG4 mutations and induced pluripotent stem cell modeling implicate oligodendrocyte progenitor cell dysfunction in familial schizophrenia

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    Schizophrenia is highly heritable, yet its underlying pathophysiology remains largely unknown. Among the most well-replicated findings in neurobiological studies of schizophrenia are deficits in myelination and white matter integrity; however, direct etiological genetic and cellular evidence has thus far been lacking. Here, we implement a family-based approach for genetic discovery in schizophrenia combined with functional analysis using induced pluripotent stem cells (iPSCs). We observed familial segregation of two rare missense mutations in Chondroitin Sulfate Proteoglycan 4 (CSPG4) (c.391G > A [p.A131T], MAF 7.79 × 10−5 and c.2702T > G [p.V901G], MAF 2.51 × 10−3). The CSPG4A131T mutation was absent from the Swedish Schizophrenia Exome Sequencing Study (2536 cases, 2543 controls), while the CSPG4V901G mutation was nominally enriched in cases (11 cases vs. 3 controls, P = 0.026, OR 3.77, 95% CI 1.05–13.52). CSPG4/NG2 is a hallmark protein of oligodendrocyte progenitor cells (OPCs). iPSC-derived OPCs from CSPG4A131T mutation carriers exhibited abnormal post-translational processing (P = 0.029), subcellular localization of mutant NG2 (P = 0.007), as well as aberrant cellular morphology (P = 3.0 × 10−8), viability (P = 8.9 × 10−7), and myelination potential (P = 0.038). Moreover, transfection of healthy non-carrier sibling OPCs confirmed a pathogenic effect on cell survival of both the CSPG4A131T (P = 0.006) and CSPG4V901G (P = 3.4 × 10−4) mutations. Finally, in vivo diffusion tensor imaging of CSPG4A131T mutation carriers demonstrated a reduction of brain white matter integrity compared to unaffected sibling and matched general population controls (P = 2.2 × 10−5). Together, our findings provide a convergence of genetic and functional evidence to implicate OPC dysfunction as a candidate pathophysiological mechanism of familial schizophrenia

    Interpersonal and social rhythm group therapy for patients with bipolar disorder

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    This article describes Interpersonal and Social Rhythm Therapy (IPSRT) adapted for use in a group setting for patients with bipolar disorder. In a preliminary efficacy study, we studied the pre-post group treatment effect on affective symptoms. One-year pre-post findings in the IPSRT group indicated that this modality was effective in reducing depressive symptoms and might reduce the number of hospital admissions. Also, group IPSRT increased stability of the social rhythm, which is thought to be important in reducing recurrence of manic and depressive episodes. These findings suggest that group IPSRT could be an additional treatment option for patients with bipolar disorder who continue to have mood episodes despite adequate pharmacotherapy and psychoeducation

    DNAJC6 Mutations Associated with Early-Onset Parkinson's Disease

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    _Objective_ DNAJC6 mutations were recently described in two families with autosomal recessive juvenile parkinsonism (onset age < 11), prominent atypical signs, poor or absent response to levodopa, and rapid progression (wheelchair-bound within ∼10 years from onset). Here, for the first time, we report DNAJC6 mutations in early-onset Parkinson's disease (PD). _Methods_ The DNAJC6 open reading frame was analyzed in 274 patients with early-onset sporadic or familial PD. Selected variants were followed up by cosegregation, homozygosity mapping, linkage analysis, whole-exome sequencing, and protein studies. _Results_ We identified two families with different novel homozygous DNAJC6 mutations segregating with PD. In each family, the DNAJC6 mutation was flanked by long runs of homozygosity within highest linkage peaks. Exome sequencing did not detect additional pathogenic variants within the linkage regions. In both families, patients showed severely decreased steady-state levels of the auxilin protein in fibroblasts. We also identified a sporadic patient carrying two rare noncoding DNAJC6 variants possibly effecting RNA splicing. All these cases fulfilled the criteria for a clinical diagnosis of early-onset PD, had symptoms onset in the third-to-fifth decade, and slow disease progression. Response to dopaminergic therapies was prominent, but, in some patients, limited by psychiatric side effects. The phenotype overlaps that of other monogenic forms of early-onset PD. _Interpretation_ Our findings delineate a novel form of hereditary early-onset PD. Screening of DNAJC6 is warranted in all patients with early-onset PD compatible with autosomal recessive inheritance. Our data provide further evidence for the involvement of synaptic vesicles endocytosis and trafficking in PD pathogenesis
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