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Full-Text Articles in Cell Biology

Huntingtin Associates With The Actin Cytoskeleton And Alpha-Actinin Isoforms To Influence Stimulus Dependent Morphology Changes, Adelaide Tousley, Maria Iuliano, Elizabeth Weisman, Ellen Sapp, Heather Richardson, Petr Vodicka, Jonathan Alexander, Neil Aronin, Marian Difiglia, Kimberly B. Kegel-Gleason Feb 2019

Huntingtin Associates With The Actin Cytoskeleton And Alpha-Actinin Isoforms To Influence Stimulus Dependent Morphology Changes, Adelaide Tousley, Maria Iuliano, Elizabeth Weisman, Ellen Sapp, Heather Richardson, Petr Vodicka, Jonathan Alexander, Neil Aronin, Marian Difiglia, Kimberly B. Kegel-Gleason

Open Access Articles

One response of cells to growth factor stimulus involves changes in morphology driven by the actin cytoskeleton and actin associated proteins which regulate functions such as cell adhesion, motility and in neurons, synaptic plasticity. Previous studies suggest that Huntingtin may be involved in regulating morphology however, there has been limited evidence linking endogenous Huntingtin localization or function with cytoplasmic actin in cells. We found that depletion of Huntingtin in human fibroblasts reduced adhesion and altered morphology and these phenotypes were made worse with growth factor stimulation, whereas the presence of the Huntington's Disease mutation inhibited growth factor induced changes ...


Trisomy Silencing By Xist Normalizes Down Syndrome Cell Pathogenesis Demonstrated For Hematopoietic Defects In Vitro, Jen-Chieh Chiang, Jun Jiang, Peter E. Newburger, Jeanne B. Lawrence Dec 2018

Trisomy Silencing By Xist Normalizes Down Syndrome Cell Pathogenesis Demonstrated For Hematopoietic Defects In Vitro, Jen-Chieh Chiang, Jun Jiang, Peter E. Newburger, Jeanne B. Lawrence

Open Access Articles

We previously demonstrated that an integrated XIST transgene can broadly repress one chromosome 21 in Down syndrome (DS) pluripotent cells. Here we address whether trisomy-silencing can normalize cell function and development sufficiently to correct cell pathogenesis, tested in an in vitro model of human fetal hematopoiesis, for which DS cellular phenotypes are best known. XIST induction in four transgenic clones reproducibly corrected over-production of megakaryocytes and erythrocytes, key to DS myeloproliferative disorder and leukemia. A contrasting increase in neural stem and iPS cells shows cell-type specificity, supporting this approach successfully rebalances the hematopoietic developmental program. Given this, we next used ...


Identification Of Epigenetic Regulators Of Dux4-Fl For Targeted Therapy Of Facioscapulohumeral Muscular Dystrophy, Charis L. Himeda, Takako I. Jones, Ching-Man A. Virbasius, Lihua Julie Zhu, Michael R. Green, Peter L. Jones Apr 2018

Identification Of Epigenetic Regulators Of Dux4-Fl For Targeted Therapy Of Facioscapulohumeral Muscular Dystrophy, Charis L. Himeda, Takako I. Jones, Ching-Man A. Virbasius, Lihua Julie Zhu, Michael R. Green, Peter L. Jones

Open Access Articles

Facioscapulohumeral muscular dystrophy (FSHD) is caused by epigenetic de-repression of the disease locus, leading to pathogenic misexpression of the DUX4 gene in skeletal muscle. While the factors and pathways involved in normal repression of the FSHD locus in healthy cells have been well characterized, very little is known about those responsible for the aberrant activation of DUX4-fl in FSHD myocytes. Reasoning that DUX4-fl activators might represent useful targets for small molecule inhibition, we performed a highly targeted, candidate-based screen of epigenetic regulators in primary FSHD myocytes. We confirmed several of the strongest and most specific candidates (ASH1L, BRD2, KDM4C, and ...


Cerebral Organoids Derived From Sandhoff Disease-Induced Pluripotent Stem Cells Exhibit Impaired Neurodifferentiation, Maria L. Allende, Emily K. Cook, Bridget C. Larman, Adrienne Nugent, Jacqueline M. Brady, Diane Golebiowski, Miguel Sena-Esteves, Cynthia J. Tifft, Richard L. Proia Mar 2018

Cerebral Organoids Derived From Sandhoff Disease-Induced Pluripotent Stem Cells Exhibit Impaired Neurodifferentiation, Maria L. Allende, Emily K. Cook, Bridget C. Larman, Adrienne Nugent, Jacqueline M. Brady, Diane Golebiowski, Miguel Sena-Esteves, Cynthia J. Tifft, Richard L. Proia

Open Access Articles

Sandhoff disease, one of the GM2 gangliosidoses, is a lysosomal storage disorder characterized by the absence of beta-hexosaminidase A and B activity and the concomitant lysosomal accumulation of its substrate, GM2 ganglioside. It features catastrophic neurodegeneration and death in early childhood. How the lysosomal accumulation of ganglioside might affect the early development of the nervous system is not understood. Recently, cerebral organoids derived from induced pluripotent stem (iPS) cells have illuminated early developmental events altered by disease processes. To develop an early neurodevelopmental model of Sandhoff disease, we first generated iPS cells from the fibroblasts of an infantile Sandhoff disease ...


A Cre-Inducible Dux4 Transgenic Mouse Model For Investigating Facioscapulohumeral Muscular Dystrophy, Takako I. Jones, Peter L. Jones Feb 2018

A Cre-Inducible Dux4 Transgenic Mouse Model For Investigating Facioscapulohumeral Muscular Dystrophy, Takako I. Jones, Peter L. Jones

Open Access Articles

The Double homeobox 4 (DUX4) gene is an important regulator of early human development and its aberrant expression is causal for facioscapulohumeral muscular dystrophy (FSHD). The DUX4-full length (DUX4-fl) mRNA splice isoform encodes a transcriptional activator; however, DUX4 and its unique DNA binding preferences are specific to old-world primates. Regardless, the somatic cytotoxicity caused by DUX4 expression is conserved when expressed in cells and animals ranging from fly to mouse. Thus, viable animal models based on DUX4-fl expression have been difficult to generate due in large part to overt developmental toxicity of low DUX4-fl expression from leaky transgenes. We have ...


Evidence That C9orf72 Dipeptide Repeat Proteins Associate With U2 Snrnp To Cause Mis-Splicing In Als/Ftd Patients, Shanye Yin, Rodrigo Lopez-Gonzalez, Ryan C. Kunz, Jaya Gangopadhyay, Carl Borufka, Steven P. Gygi, Fen-Biao Gao, Robin Reed Jun 2017

Evidence That C9orf72 Dipeptide Repeat Proteins Associate With U2 Snrnp To Cause Mis-Splicing In Als/Ftd Patients, Shanye Yin, Rodrigo Lopez-Gonzalez, Ryan C. Kunz, Jaya Gangopadhyay, Carl Borufka, Steven P. Gygi, Fen-Biao Gao, Robin Reed

Open Access Articles

Hexanucleotide repeat expansion in the C9ORF72 gene results in production of dipeptide repeat (DPR) proteins that may disrupt pre-mRNA splicing in amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) patients. At present, the mechanisms underlying this mis-splicing are not understood. Here, we show that addition of proline-arginine (PR) and glycine-arginine (GR) toxic DPR peptides to nuclear extracts blocks spliceosome assembly and splicing, but not other types of RNA processing. Proteomic and biochemical analyses identified the U2 small nuclear ribonucleoprotein particle (snRNP) as a major interactor of PR and GR peptides. In addition, U2 snRNP, but not other splicing factors, mislocalizes ...


Allele-Selective Suppression Of Mutant Huntingtin In Primary Human Blood Cells, James R. C. Miller, Edith L. Pfister, Wanzhao Liu, Ralph Andre, Ulrike Trager, Lori A. Kennington, Kimberly Lo, Sipke Dijkstra, Douglas Macdonald, Gary R. Ostroff, Neil Aronin, Sarah J. Tabrizi Apr 2017

Allele-Selective Suppression Of Mutant Huntingtin In Primary Human Blood Cells, James R. C. Miller, Edith L. Pfister, Wanzhao Liu, Ralph Andre, Ulrike Trager, Lori A. Kennington, Kimberly Lo, Sipke Dijkstra, Douglas Macdonald, Gary R. Ostroff, Neil Aronin, Sarah J. Tabrizi

Open Access Articles

Post-transcriptional gene silencing is a promising therapy for the monogenic, autosomal dominant, Huntington's disease (HD). However, wild-type huntingtin (HTT) has important cellular functions, so the ideal strategy would selectively lower mutant HTT while sparing wild-type. HD patients were genotyped for heterozygosity at three SNP sites, before phasing each SNP allele to wild-type or mutant HTT. Primary ex vivo myeloid cells were isolated from heterozygous patients and transfected with SNP-targeted siRNA, using glucan particles taken up by phagocytosis. Highly selective mRNA knockdown was achieved when targeting each allele of rs362331 in exon 50 of the HTT transcript; this selectivity was ...


Large Family Cohorts Of Lymphoblastoid Cells Provide A New Cellular Model For Investigating Facioscapulohumeral Muscular Dystrophy, Takako I. Jones, Charis L. Himeda, Daniel P. Perez, Peter L. Jones Mar 2017

Large Family Cohorts Of Lymphoblastoid Cells Provide A New Cellular Model For Investigating Facioscapulohumeral Muscular Dystrophy, Takako I. Jones, Charis L. Himeda, Daniel P. Perez, Peter L. Jones

Open Access Articles

Facioscapulohumeral muscular dystrophy (FSHD) is associated with aberrant epigenetic regulation of the chromosome 4q35 D4Z4 macrosatellite repeat. The resulting DNA hypomethylation and relaxation of epigenetic repression leads to increased expression of the deleterious DUX4-fl mRNA encoded within the distal D4Z4 repeat. With the typical late onset of muscle weakness, prevalence of asymptomatic individuals, and an autosomal dominant mode of inheritance, FSHD is often passed on from one generation to the next and affects multiple individuals within a family. Here we have characterized unique collections of 114 lymphoblastoid cell lines (LCLs) generated from 12 multigenerational FSHD families, including 56 LCLs from ...


Autophagy Activation By Transcription Factor Eb (Tfeb) In Striatum Of Hdq175/Q7 Mice, Petr Vodicka, Kathryn O. Chase, Maria Iuliano, Adelaide Tousley, Dana T. Valentine, Ellen Sapp, Kimberly B. Kegel-Gleason, Miguel Sena-Esteves, Neil Aronin, Marian Difiglia Oct 2016

Autophagy Activation By Transcription Factor Eb (Tfeb) In Striatum Of Hdq175/Q7 Mice, Petr Vodicka, Kathryn O. Chase, Maria Iuliano, Adelaide Tousley, Dana T. Valentine, Ellen Sapp, Kimberly B. Kegel-Gleason, Miguel Sena-Esteves, Neil Aronin, Marian Difiglia

Open Access Articles

BACKGROUND: Mutant huntingtin (mHTT) is encoded by the Huntington's disease (HD) gene and its accumulation in the brain contributes to HD pathogenesis. Reducing mHTT levels through activation of the autophagosome-lysosomal pathway may have therapeutic benefit. Transcription factor EB (TFEB) regulates lysosome biogenesis and autophagy.

OBJECTIVE: To examine if increasing TFEB protein levels in HD mouse striatum induces autophagy and influences mHTT levels.

METHODS: We introduced cDNA encoding TFEB with an HA tag (TFEB-HA) under the control of neuron specific synapsin 1 promoter into the striatum of 3 month old HDQ175/Q7 mice using adeno-associated virus AAV2/9. The levels ...


Mmp-9 And Mmp-2 Contribute To Neuronal Cell Death In Ipsc Models Of Frontotemporal Dementia With Mapt Mutations, Md Helal Uddin Biswas, Sandra Almeida, Rodrigo Lopez-Gonzalez, Wenjie Mao, Zhijun Zhang, Anna M. Karydas, Michael D. Geschwind, Jacek Biernat, Eva-Maria Mandelkow, Kensuke Futai, Bruce L. Miller, Fen-Biao Gao Sep 2016

Mmp-9 And Mmp-2 Contribute To Neuronal Cell Death In Ipsc Models Of Frontotemporal Dementia With Mapt Mutations, Md Helal Uddin Biswas, Sandra Almeida, Rodrigo Lopez-Gonzalez, Wenjie Mao, Zhijun Zhang, Anna M. Karydas, Michael D. Geschwind, Jacek Biernat, Eva-Maria Mandelkow, Kensuke Futai, Bruce L. Miller, Fen-Biao Gao

Open Access Articles

How mutations in the microtubule-associated protein tau (MAPT) gene cause frontotemporal dementia (FTD) remains poorly understood. We generated and characterized multiple induced pluripotent stem cell (iPSC) lines from patients with MAPT IVS10+16 and tau-A152T mutations and a control subject. In cortical neurons differentiated from these and other published iPSC lines, we found that MAPT mutations do not affect neuronal differentiation but increase the 4R/3R tau ratio. Patient neurons had significantly higher levels of MMP-9 and MMP-2 and were more sensitive to stress-induced cell death. Inhibitors of MMP-9/MMP-2 protected patient neurons from stress-induced cell death and recombinant MMP-9 ...


Human Ipsc-Derived Neuronal Model Of Tau-A152t Frontotemporal Dementia Reveals Tau-Mediated Mechanisms Of Neuronal Vulnerability, M. Catarina Silva, Sandra Almeida, Md Helal Uddin Biswas, Zhijun Zhang, Fen-Biao Gao, Stephen J. Haggarty Sep 2016

Human Ipsc-Derived Neuronal Model Of Tau-A152t Frontotemporal Dementia Reveals Tau-Mediated Mechanisms Of Neuronal Vulnerability, M. Catarina Silva, Sandra Almeida, Md Helal Uddin Biswas, Zhijun Zhang, Fen-Biao Gao, Stephen J. Haggarty

Open Access Articles

Frontotemporal dementia (FTD) and other tauopathies characterized by focal brain neurodegeneration and pathological accumulation of proteins are commonly associated with tau mutations. However, the mechanism of neuronal loss is not fully understood. To identify molecular events associated with tauopathy, we studied induced pluripotent stem cell (iPSC)-derived neurons from individuals carrying the tau-A152T variant. We highlight the potential of in-depth phenotyping of human neuronal cell models for pre-clinical studies and identification of modulators of endogenous tau toxicity. Through a panel of biochemical and cellular assays, A152T neurons showed accumulation, redistribution, and decreased solubility of tau. Upregulation of tau was coupled ...


Ggggcc Microsatellite Rna Is Neuritically Localized, Induces Branching Defects, And Perturbs Transport Granule Function, Alondra Schweizer Burguete, Sandra Almeida, Fen-Biao Gao, Robert Kalb, Michael R. Akins, Nancy M. Bonini Dec 2015

Ggggcc Microsatellite Rna Is Neuritically Localized, Induces Branching Defects, And Perturbs Transport Granule Function, Alondra Schweizer Burguete, Sandra Almeida, Fen-Biao Gao, Robert Kalb, Michael R. Akins, Nancy M. Bonini

Open Access Articles

Microsatellite expansions are the leading cause of numerous neurodegenerative disorders. Here we demonstrate that GGGGCC and CAG microsatellite repeat RNAs associated with C9orf72 in ALS/FTD and with polyglutamine diseases, respectively, localize to neuritic granules that undergo active transport into distal neuritic segments. In cultured mammalian spinal cord neurons, the presence of neuritic GGGGCC repeat RNA correlates with neuronal branching defects and the repeat RNA localizes to granules that label with FMRP, a transport granule component. Using a Drosophila GGGGCC expansion disease model, we characterize dendritic branching defects that are modulated by FMRP and Orb2. The human orthologues of these ...


Individual Epigenetic Status Of The Pathogenic D4z4 Macrosatellite Correlates With Disease In Facioscapulohumeral Muscular Dystrophy, Takako I. Jones, Oliver D. King, Charis L. Himeda, Sachiko Homma, Jennifer C. J. Chen, Mary Lou. Beermann, Chi Yan, Charles P. Emerson Jr., Jeffrey B. Miller, Kathryn R. Wagner, Peter L. Jones Mar 2015

Individual Epigenetic Status Of The Pathogenic D4z4 Macrosatellite Correlates With Disease In Facioscapulohumeral Muscular Dystrophy, Takako I. Jones, Oliver D. King, Charis L. Himeda, Sachiko Homma, Jennifer C. J. Chen, Mary Lou. Beermann, Chi Yan, Charles P. Emerson Jr., Jeffrey B. Miller, Kathryn R. Wagner, Peter L. Jones

Open Access Articles

BACKGROUND: Both forms of facioscapulohumeral muscular dystrophy (FSHD) are associated with aberrant epigenetic regulation of the chromosome 4q35 D4Z4 macrosatellite. Chromatin changes due to large deletions of heterochromatin (FSHD1) or mutations in chromatin regulatory proteins (FSHD2) lead to relaxation of epigenetic repression and increased expression of the deleterious double homeobox 4 (DUX4) gene encoded within the distal D4Z4 repeat. However, many individuals with the genetic requirements for FSHD remain asymptomatic throughout their lives. Here we investigated family cohorts of FSHD1 individuals who were either affected (manifesting) or without any discernible weakness (nonmanifesting/asymptomatic) and their unaffected family members to determine ...