22q11欠失症候群モデルマウスの神経発達障害には、マイクロRNAが介在するCxcr4/Cxcl12シグナリングの欠損が寄与する

22q11 deletion syndrome (22q11DS) frequently accompanies psychiatric conditions, some of which are classified as schizophrenia and bipolar disorder in the current diagnostic categorization. However, it remains elusive how the chromosomal microdeletion leads to the mental manifestation at the mechanistic level. Here we show that a 22q11DS mouse model with a deletion of 18 orthologous genes of human 22q11 (Df1/+ mice) has deficits in migration of cortical interneurons and hippocampal dentate precursor cells. Furthermore, Df1/+ mice show functional defects in Chemokine receptor 4/Chemokine ligand 12 (Cxcr4/Cxcl12; Sdf1) signaling, which reportedly underlie interneuron migration. Notably, the defects in interneuron progenitors are rescued by ectopic expression of Dgcr8, one of the genes in 22q11 microdeletion. Furthermore, heterozygous knockout mice for Dgcr8 show similar neurodevelopmental abnormalities as Df1/+ mice. Thus, Dgcr8-mediated regulation of microRNA is likely to underlie Cxcr4/Cxcl12 signaling and associated neurodevelopmental defects. Finally, we observe that expression of CXCL12 is decreased in olfactory neurons from sporadic cases with schizophrenia compared with normal controls. Given the increased risk of 22q11DS in schizophrenia that frequently shows interneuron abnormalities, the overall study suggests that CXCR4/CXCL12 signaling may represent a common downstream mediator in the pathophysiology of schizophrenia and related mental conditions.博士（医学）・乙1331号・平成26年3月17

Neuronal migration abnormalities and its possible implications for schizophrenia

Schizophrenia is a complex mental disorder that displays behavioral deficits such as decreased sensory gating, reduced social interaction and working memory deficits. The neurodevelopmental model is one of the widely accepted hypotheses of the etiology of schizophrenia. Subtle developmental abnormalities of the brain which stated long before the onset of clinical symptoms are thought to lead to the emergence of illness. Schizophrenia has strong genetic components but its underlying molecular pathogenesis is still poorly understood. Genetic linkage and association studies have identified several genes involved in neuronal migrations as candidate susceptibility genes for schizophrenia, although their effect size is small. Recent progress in copy number variation studies also has identified much higher risk loci such as 22q11. Based on these genetic findings, we are now able to utilize genetically-defined animal models. Here we summarize the results of neurodevelopmental and behavioral analysis of genetically-defined animal models. Furthermore, animal model experiments have demonstrated that embryonic and perinatal neurodevelopmental insults in neurogenesis and neuronal migrations cause neuronal functional and behavioral deficits in affected adult animals, which are similar to those of schizophrenic patients. However, these findings do not establish causative relationship. Genetically-defined animal models are a critical approach to explore the relationship between neuronal migration abnormalities and behavioral abnormalities relevant to Schizophrenia

Arsenic Trioxide Sensitizes Glioblastoma to a Myc Inhibitor

<div><p>Glioblastoma multiforme (GBM) is associated with high mortality due to infiltrative growth and recurrence. Median survival of the patients is less than 15 months, increasing requirements for new therapies. We found that both arsenic trioxide and 10058F4, an inhibitor of Myc, induced differentiation of cancer stem-like cells (CSC) of GBM and that arsenic trioxide drastically enhanced the anti-proliferative effect of 10058F4 but not apoptotic effects. EGFR-driven genetically engineered GBM mouse model showed that this cooperative effect is higher in EGFRvIII-expressing <i>INK4a/Arf^-/-</i> neural stem cells (NSCs) than in control wild type NSCs. In addition, treatment of GBM CSC xenografts with arsenic trioxide and 10058F4 resulted in significant decrease in tumor growth and increased differentiation with concomitant decrease of proneural and mesenchymal GBM CSCs <i>in vivo</i>. Our study was the first to evaluate arsenic trioxide and 10058F4 interaction in GBM CSC differentiation and to assess new opportunities for arsenic trioxide and 10058F4 combination as a promising approach for future differentiation therapy of GBM.</p></div

Arsenic trioxide enhanced the inhibitory effect of 10058F4 on GBM CSC growth but not the apoptosis-inducing effect of 10058F4.

<p>GBM CSCs (RI02, RI08) were treated with or without 2μM arsenic trioxide or 60μM 10058F4 for 24, 72 and 168h in the presence of 1% FCS. Results are presented as the relative cell growth (A), the activation of Caspase3/7 (B) and the percentages of Tunel⁺ cells (C) as determined with PrestoBlue Cell Viability Reagent, CellEvent Caspase-3/7 Green Detection Reagent and Tunel assay, respectively. Cell viability is presented as the mean ± SD. The relative fluorescent units of treated cells were normalized to the cell viability and presented as the mean ± SD. *P = 0.017, **P = 0.019, ^#P = 0.72, ^##P = 0.43.</p

10058F4 but not arsenic trioxide activated Shh signaling in GBM CSCs.

<p>GBM CSCs were transfected with a reporter construct containing a response element for Gli. After 24 hour 10058F4 (60μM) and arsenic trioxide (2μM) treatment, luciferase assay was performed. Results are the mean ± S.D. of triplicate data points from a representative experiment. *P = 0.0065 ** P = 0.0043, ***P = 0.0050, ****P = 0.0091, ^#P = 0.023028, ^##P = 0.00015.</p

Constitutive activation of EGFR with loss of <i>Ink4/Arf</i> enhanced the responsiveness of neural stem cells to arsenic trioxide and 10058F4.

<p>(A)-(C) Immunofluorescent analysis for Nestin (green, (A)), TujI (green (B)), GFAP (red (C)) and DAPI staining of nuclei (blue) and quantitative analysis of Nestin-positive(A), Tuj1-positive cells (B), GFAP-positive cells (C) in <i>Ink4/Arf</i>^<i>-/-</i>—EGFRvIII and control neural stem cells 3days after treatment with or without 2μM arsenic trioxide or 60μM 10058F4. Scale bar = 100μm. The data is the mean ± S.D. *P = 0.00001, **P = 0.0041. (D) Dose effects of 10058F4 to <i>Ink4/Arf</i>^<i>-/-</i>—EGFRvIII and control neural stem cells in combination with or without 2μM arsenic trioxide for 72h. Results are presented as the relative cell growth as determined with PrestoBlue Cell Viability Reagent. Cell viability is presented as the mean ± SD.</p

Arsenic trioxide and 10058F4 combination treatment efficiently regressed established gliomas.

<p>Experimental Design. GBM CSCs (RI03) CSCs (5 × 10⁴ cells) were implanted intracranially into SCID mice. Two months after transplantation, tumor growth was monitored by MRI. Four days after tumor size measurement, Arsenic Trioxide (2.5 mg/kg), 10058F4 (25mg/Kg) or both were administered by i.p. injection once a day for 10 days. After 10-day drug treatments, tumor sizes were again measured. Representative images of T2-weighted MRI. The region of interest used to calculate the volume of brain tumor is indicated by a dashed line. (C)-(D) Representative photographs of hematoxylin / eosin staining of intracranial xenograft brain tumors. The boxed area in (C) is magnified in (D). Scale bar = 500μm. (E)-(F) Changes in tumor volume after 10-day treatment with arsenic trioxide and 10058F4 relative to the starting tumor volume for each individual mouse. Each bar represents a volume change of an individual mouse. The data in (E) is shown as the mean ± SD of the data for each individual mouse in (F).</p