title: HDAC inhibitor 4-phenylbutyrate preserves immature phenotype of human embryonic midbrain stem cells: implications for the involvement of DNA methyltransferase.
abstract: Cell replacement and gene therapy using neural stem cells (NSCs) have been             widely touted as a promising treatment for CNS diseases including brain tumors.             Histone deacetylase (HDAC) inhibitors have been used to explore mechanisms behind             the lineage-specific differentiation of NSCs and as modulators of gene therapy.             We have used the human embryonic midbrain stem cell line NGC-407 and the HDAC             inhibitor 4-phenylbutyrate (4-PB) to investigate the differentiation from epigenetic             perspectives. NGC-407 cells can differentiate into both neurons and glial cells,             evidenced by morphological characteristics as well as up-regulation of the respective             markers β-tubulin III and glial fibrillary acidic protein (GFAP) and simultaneous             down-regulation of the NSC-marker nestin. Genomic DNA extracted from the differentiating             cells was globally more methylated than that of the proliferating cells. The differentiating             cells showed increased expression of the de novo DNA methyltransferase DNMT3B             along with strong immunoreactivity in the cell nuclei. When these cells were treated             with 4-PB, both the astrocytic and the neuronal differentiation phenotypes were             suppressed, which paralleled a substantially weakened DNMT3B immunoreactivity             in the cell nuclei. Importantly, 4-PB treatment preserves the immature phenotype             of these differentiating cells as indicated by Western blot analysis and immunocytochemical             analyses of the NSC markers, nestin and CD133. Nestin becomes entirely degraded             5 days after induction of differentiation, but upon exposure to 4-PB, some of             the differentiating cells retain the integrity of nestin and concurrently, CD133             is also up-regulated. Taken together, the data suggests that HDAC activity is             necessary for human embryonic NSC differentiation.
authors: Department of Clinical Neuroscience, Center for Molecular Medicine,                     Karolinska Institutet, Karolinska University Hospital, Solna, SE-17176                     Stockholm, Sweden.
authors: Zahidul
authors: Z
authors: Khan
authors: Monira
authors: M
authors: Akhtar
authors: Tomas J
authors: TJ
authors: Ekström
mesh_terms: D015415:Biomarkers / Q000032:analysis*; D001932:Brain Neoplasms / Q000235:genetics / Q000473:pathology / Q000628:therapy*; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D002460:Cell Line; D049109:Cell Proliferation; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000235:genetics / Q000378:metabolism*; D053595:Embryonic Stem Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D015316:Genetic Therapy / Q000379:methods*; D005904:Glial Fibrillary Acidic Protein / Q000032:analysis / Q000096:biosynthesis; D056572:Histone Deacetylase Inhibitors / Q000494:pharmacology; D006655:Histone Deacetylases / Q000378:metabolism*; D006801:Humans; D007381:Intermediate Filament Proteins / Q000032:analysis / Q000096:biosynthesis; D008636:Mesencephalon / Q000166:cytology* / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000032:analysis / Q000096:biosynthesis; D064231:Nestin; D009457:Neuroglia / Q000166:cytology / Q000378:metabolism; D009474:Neurons / Q000166:cytology / Q000378:metabolism; D010641:Phenotype; D010654:Phenylbutyrates / Q000494:pharmacology*; D033581:Stem Cell Transplantation; D014404:Tubulin / Q000032:analysis / Q000096:biosynthesis; D000097584:DNA Methyltransferase 3B
chemical_list: D015415:Biomarkers; D004248:DNA (Cytosine-5-)-Methyltransferases; D005904:Glial Fibrillary Acidic Protein; D056572:Histone Deacetylase Inhibitors; D006655:Histone Deacetylases; D007381:Intermediate Filament Proteins; D009419:Nerve Tissue Proteins; D064231:Nestin; D010654:Phenylbutyrates; D014404:Tubulin; D000097584:DNA Methyltransferase 3B; C577484:NES protein, human; C075773:4-phenylbutyric acid