title: DOT1L Activity Promotes Proliferation and Protects Cortical Neural Stem Cells from Activation of ATF4-DDIT3-Mediated ER Stress In Vitro.
abstract: Growing evidence suggests that the lysine methyltransferase DOT1L/KMT4 has important roles in proliferation, survival, and differentiation of stem cells in development and in disease. We investigated the function of DOT1L in neural stem cells (NSCs) of the cerebral cortex. The pharmacological inhibition and shRNA-mediated knockdown of DOT1L impaired proliferation and survival of NSCs. DOT1L inhibition specifically induced genes that are activated during the unfolded protein response (UPR) in the endoplasmic reticulum (ER). Chromatin-immunoprecipitation analyses revealed that two genes encoding for central molecules involved in the ER stress response, Atf4 and Ddit3 (Chop), are marked with H3K79 methylation. Interference with DOT1L activity resulted in transcriptional activation of both genes accompanied by decreased levels of H3K79 dimethylation. Although downstream effectors of the UPR, such as Ppp1r15a/Gadd34, Atf3, and Tnfrsf10b/Dr5 were also transcriptionally activated, this most likely occurred in response to increased ATF4 expression rather than as a direct consequence of altered H3K79 methylation. While stem cells are particularly vulnerable to stress, the UPR and ER stress have not been extensively studied in these cells yet. Since activation of the ER stress program is also implicated in directing stem cells into differentiation or to maintain a proliferative status, the UPR must be tightly regulated. Our and published data suggest that histone modifications, including H3K4me3, H3K14ac, and H3K79me2, are implicated in the control of transcriptional activation of ER stress genes. In this context, the loss of H3K79me2 at the Atf4- and Ddit3-promoters appears to mark a point-of-no-return that activates the death program in NSCs.
authors: Department of Molecular Embryology, Institute of Anatomy and Cell Biology, Albert-Ludwigs-University, Freiburg, Freiburg, Germany.|Hermann Staudinger Graduate School, Albert-Ludwigs-University, Freiburg, Freiburg, Germany.
authors: Deborah
authors: D
authors: Roidl
authors: Department of Molecular Embryology, Institute of Anatomy and Cell Biology, Albert-Ludwigs-University, Freiburg, Freiburg, Germany.
authors: Nicole
authors: N
authors: Hellbach
authors: Department of Molecular Embryology, Institute of Anatomy and Cell Biology, Albert-Ludwigs-University, Freiburg, Freiburg, Germany.|Faculty of Biology, Albert-Ludwigs-University, Freiburg, Freiburg, Germany.
authors: Patrick P
authors: PP
authors: Bovio
authors: Department of Molecular Embryology, Institute of Anatomy and Cell Biology, Albert-Ludwigs-University, Freiburg, Freiburg, Germany.
authors: Alejandro
authors: A
authors: Villarreal
authors: Department of Molecular Embryology, Institute of Anatomy and Cell Biology, Albert-Ludwigs-University, Freiburg, Freiburg, Germany.
authors: Stefanie
authors: S
authors: Heidrich
authors: Department of Neuroanatomy, Institute of Anatomy and Cell Biology, Albert-Ludwigs-University, Freiburg, Freiburg, Germany.
authors: Sigrun
authors: S
authors: Nestel
authors: Bioinformatics Group, Department of Computer Science, Albert-Ludwigs-University, Freiburg, Freiburg, Germany.|Pharmaceutical Bioinformatics, Institute of Pharmaceutical Science, Albert-Ludwigs-University Freiburg, Freiburg, Germany.
authors: Björn A
authors: BA
authors: Grüning
authors: Deep Sequencing Facility, Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany.
authors: Ulrike
authors: U
authors: Boenisch
authors: Department of Molecular Embryology, Institute of Anatomy and Cell Biology, Albert-Ludwigs-University, Freiburg, Freiburg, Germany.
authors: Tanja
authors: T
authors: Vogel
mesh_terms: D051701:Activating Transcription Factor 4 / Q000378:metabolism*; D000818:Animals; D001562:Benzimidazoles / Q000494:pharmacology; D002454:Cell Differentiation; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology*; D004721:Endoplasmic Reticulum / Q000378:metabolism / Q000648:ultrastructure; D059865:Endoplasmic Reticulum Stress / Q000187:drug effects / Q000235:genetics; D005786:Gene Expression Regulation / Q000187:drug effects; D011495:Histone-Lysine N-Methyltransferase; D006657:Histones / Q000378:metabolism; D008239:Lysine; D008745:Methylation / Q000187:drug effects; D008780:Methyltransferases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D051379:Mice; D058953:Neural Stem Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D000066829:Neuroprotection / Q000187:drug effects; D051742:Transcription Factor CHOP / Q000378:metabolism*; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: C081452:Atf4 protein, mouse; D001562:Benzimidazoles; C497250:Ddit3 protein, mouse; C583893:EPZ-5676; D006657:Histones; D051701:Activating Transcription Factor 4; D051742:Transcription Factor CHOP; C481527:Dot1l protein, mouse; D008780:Methyltransferases; D011495:Histone-Lysine N-Methyltransferase; D008239:Lysine
keywords: Cerebral cortex; Endoplasmic reticulum stress; H3K79; Histone H3 methylation; Neural stem cells; Unfolded protein response