22 research outputs found

    Loss of Cep120 results in early embryonic lethality, hydrocephalus, and cerebellar hypoplasia in mice.

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    <p>(A) The gene targeting strategy used to create mouse <i>Cep120<sup>-</sup></i> and <i>Cep120<sup>f</sup></i> mutant alleles. Open rectangles refer to exons (which are numbered), lines to introns, grey rectangles to Frt sites, and triangles to loxP sites. BglII (Bg) restriction sites and a probe for Southern blot are indicated. Neo, neomycin gene; DTA, diphtheria toxin A gene. (B) Southern blot analysis shows a representative mutant and wild type (wt) ES cell clones. (C) Lateral view of wild type and <i>Cep120<sup>-/-</sup></i> embryos. Note that the development of Cep120 mutant embryos is delayed and the heart loops in the opposite direction (indicated by the arrow). (D–G) Morphology of two-week-old (P14) unskinned mouse heads (D), brains (E, F), and cerebellums (G), with indicated genotypes. The lines are in the same length for both wt and mutant, thus indicating the relative brain size or the extent of hydrocephalus in the mutant. Hematoxylin and eosin (H&E) staining of sagittal brain sections (E) confirms that the mutant ventricles of the brain are severely dilated. The boxed area in F is enlarged in (G). Cerebellums are outlined. The mutant cerebellum is significantly smaller (F).</p

    The Cep120 mutation results in cerebellar hypoplasia.

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    <p>Sagittal sections of P1, P7, and P14 wild type and <i>Cep120<sup>f/-</sup></i>; <i>nes-Cre</i> mutant cerebellums were stained with cresyl violet. Framed areas are enlarged in the corresponding lower panels. EGL, external granule cell layer; PCL, Purkinje cell layer; ML, molecular layer; and IGL, inner granule layer.</p

    Loss of Cep120 results in failed expansion of granule neuron progenitors (GNPs), due to lack of a response to Hedgehog signaling.

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    <p>(A–F) Sagittal sections of P1, P7, and P14 wild type and mutant cerebellums were coimmunostained for Pax6 (red), Calb1 (green), and nuclei (DAPI, blue). Pax6 and Calb1 label GNPs and Purkinje cells, respectively. Framed areas in panels A–F are enlarged in A′–F′. EGL, external granule cell layer; PCL, Purkinje cell layer; ML, molecular layer; IGL, inner granule layer. Genotypes are shown to the left. (G–H) LacZ staining of the P7 cerebellum is positive in wild type animals (G), but negative in the Cep120 mutant (H). Genotypes are indicated on both sides. Cerebellums are outlined, and cerebellar posterior lobes are indicated by asterisks.</p

    Failed centriole duplication, maturation, and ciliogenesis in cerebellar granule neuron progenitors (CGNPs) and ependymal cells in the Cep120 mutant.

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    <p>(A–D) Sagittal brain sections of P14 mice with the indicated genotypes were coimmunostained for acetylated α ˜tubulin and Arl13b, cilia markers. The fourth ventricular choroid plexus is circled. Framed areas in panels A and B are enlarged in A′/A″ and B′/B″. Panels A″ and B″ show representative areas of ependyma near the fourth ventricle. Panels C and D show representative areas of CGNPs. Arrowheads indicate representative cilia. Note that cilia develop in the <i>Cep120<sup>f/-</sup></i>; <i>nes-Cre</i> choroid plexus, but not in ependymal cells and CGNPs. (G–L) Sagittal cerebellar sections of P14 mice with the indicated genotypes were coimmunostained for γ ˜tubulin and Cep120, Odf2, or Ta3, as shown. Note that very few centrioles are present in <i>Cep120<sup>f/-</sup></i>; <i>nes-Cre</i> CGNPs, relative to wild type CGNPs. Arrowheads indicate one or two representative centrioles in each panel.</p

    Ta3 is required for asymmetrical localization of Cep120 to the daughter centriole.

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    <p>Wild type and <i>Ta3</i> mutant primary mouse embryonic fibroblasts (pMEFs) were coimmunostained for Cep120 and γ ˜tubulin (A) or Odf2 and Cep120 (B), together with DAPI (for nuclei). Arrowheads indicate the specific staining at centrioles. The Cep120 signal at the daughter and mother centrioles (DC and MC, respectively) was quantified for 21 randomly chosen cells, using NIH image J. Cep120 signal ratios were then calculated, specifically the DC to MC ratio and the wild type to Ta3 mutant ratio (average + standard deviation) (C). (D) No significant changes in Cep120 levels in <i>Ta3</i> mutant MEFs. Immunoblots show the expression of endogenous Ta3 and Cep120 in wild type and <i>Ta3</i> mutant MEFs, with tubulin as a loading control.</p

    Cep120 is required for centriole duplication and ciliogenesis.

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    <p>Wild type and <i>Cep120<sup>-/-</sup></i> pMEFs were coimmunostained for the indicated proteins. Most Cep120 mutant cells lacked either one or both centrioles, as indicated by γ ˜tubulin staining. Staining for Cep164, Ta3, and Odf2 showed that the missing centriole was the mother centriole. Staining for Arl13b and acetylated α ˜tubulin indicated no cilia being formed in Cep120 mutant cells. Arrowheads point to the staining of γ ˜tubulin (a centriole marker), the indicated proteins, or cilia.</p

    Image_1_Histone Deacetylase Inhibitor Alleviates the Neurodegenerative Phenotypes and Histone Dysregulation in Presenilins-Deficient Mice.pdf

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    <p>Histone acetylation has been shown to play a crucial role in memory formation, and histone deacetylase (HDAC) inhibitor sodium butyrate (NaB) has been demonstrated to improve memory performance and rescue the neurodegeneration of several Alzheimer’s Disease (AD) mouse models. The forebrain presenilin-1 and presenilin-2 conditional double knockout (cDKO) mice showed memory impairment, forebrain degeneration, tau hyperphosphorylation and inflammation that closely mimics AD-like phenotypes. In this article, we have investigated the effects of systemic administration of NaB on neurodegenerative phenotypes in cDKO mice. We found that chronic NaB treatment significantly restored contextual memory but did not alter cued memory in cDKO mice while such an effect was not permanent after treatment withdrawal. We further revealed that NaB treatment did not rescue reduced synaptic numbers and cortical shrinkage in cDKO mice, but significantly increased the neurogenesis in subgranular zone of dentate gyrus (DG). We also observed that tau hyperphosphorylation and inflammation related protein glial fibrillary acidic protein (GFAP) level were decreased in cDKO mice by NaB. Furthermore, GO and pathway analysis for the RNA-Seq data demonstrated that NaB treatment induced enrichment of transcripts associated with inflammation/immune processes and cytokine-cytokine receptor interactions. RT-PCR confirmed that NaB treatment inhibited the expression of inflammation related genes such as S100a9 and Ccl4 found upregulated in the brain of cDKO mice. Surprisingly, the level of brain histone acetylation in cDKO mice was dramatically increased and was decreased by the administration of NaB, which may reflect dysregulation of histone acetylation underlying memory impairment in cDKO mice. These results shed some lights on the possible molecular mechanisms of HDAC inhibitor in alleviating the neurodegenerative phenotypes of cDKO mice and provide a promising target for treating AD.</p

    Table_2_Histone Deacetylase Inhibitor Alleviates the Neurodegenerative Phenotypes and Histone Dysregulation in Presenilins-Deficient Mice.pdf

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    <p>Histone acetylation has been shown to play a crucial role in memory formation, and histone deacetylase (HDAC) inhibitor sodium butyrate (NaB) has been demonstrated to improve memory performance and rescue the neurodegeneration of several Alzheimer’s Disease (AD) mouse models. The forebrain presenilin-1 and presenilin-2 conditional double knockout (cDKO) mice showed memory impairment, forebrain degeneration, tau hyperphosphorylation and inflammation that closely mimics AD-like phenotypes. In this article, we have investigated the effects of systemic administration of NaB on neurodegenerative phenotypes in cDKO mice. We found that chronic NaB treatment significantly restored contextual memory but did not alter cued memory in cDKO mice while such an effect was not permanent after treatment withdrawal. We further revealed that NaB treatment did not rescue reduced synaptic numbers and cortical shrinkage in cDKO mice, but significantly increased the neurogenesis in subgranular zone of dentate gyrus (DG). We also observed that tau hyperphosphorylation and inflammation related protein glial fibrillary acidic protein (GFAP) level were decreased in cDKO mice by NaB. Furthermore, GO and pathway analysis for the RNA-Seq data demonstrated that NaB treatment induced enrichment of transcripts associated with inflammation/immune processes and cytokine-cytokine receptor interactions. RT-PCR confirmed that NaB treatment inhibited the expression of inflammation related genes such as S100a9 and Ccl4 found upregulated in the brain of cDKO mice. Surprisingly, the level of brain histone acetylation in cDKO mice was dramatically increased and was decreased by the administration of NaB, which may reflect dysregulation of histone acetylation underlying memory impairment in cDKO mice. These results shed some lights on the possible molecular mechanisms of HDAC inhibitor in alleviating the neurodegenerative phenotypes of cDKO mice and provide a promising target for treating AD.</p
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