title: Dynamic regulation of Schwann cell enhancers after peripheral nerve injury.
abstract: Myelination of the peripheral nervous system is required for axonal function and long term stability. After peripheral nerve injury, Schwann cells transition from axon myelination to a demyelinated state that supports neuronal survival and ultimately remyelination of axons. Reprogramming of gene expression patterns during development and injury responses is shaped by the actions of distal regulatory elements that integrate the actions of multiple transcription factors. We used ChIP-seq to measure changes in histone H3K27 acetylation, a mark of active enhancers, to identify enhancers in myelinating rat peripheral nerve and their dynamics after demyelinating nerve injury. Analysis of injury-induced enhancers identified enriched motifs for c-Jun, a transcription factor required for Schwann cells to support nerve regeneration. We identify a c-Jun-bound enhancer in the gene for Runx2, a transcription factor induced after nerve injury, and we show that Runx2 is required for activation of other induced genes. In contrast, enhancers that lose H3K27ac after nerve injury are enriched for binding sites of the Sox10 and early growth response 2 (Egr2/Krox20) transcription factors, which are critical determinants of Schwann cell differentiation. Egr2 expression is lost after nerve injury, and many Egr2-binding sites lose H3K27ac after nerve injury. However, the majority of Egr2-bound enhancers retain H3K27ac, indicating that other transcription factors maintain active enhancer status after nerve injury. The global epigenomic changes in H3K27ac deposition pinpoint dynamic changes in enhancers that mediate the effects of transcription factors that control Schwann cell myelination and peripheral nervous system responses to nerve injury.
authors.affiliation: From the Waisman Center, Cellular and Molecular Pathology Graduate Program, and.
authors.forename: Holly A
authors.initials: HA
authors.lastname: Hung
authors.affiliation: Departments of Biostatistics and Medical Informatics and.
authors.forename: Guannan
authors.initials: G
authors.lastname: Sun
authors.affiliation: Departments of Biostatistics and Medical Informatics and.
authors.forename: Sunduz
authors.initials: S
authors.lastname: Keles
authors.affiliation: From the Waisman Center, Comparative Biosciences, University of Wisconsin-Madison, Madison, Wisconsin 53705 jpsvaren@wisc.edu.
authors.forename: John
authors.initials: J
authors.lastname: Svaren
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D050659:Core Binding Factor Alpha 1 Subunit / Q000235:genetics / Q000378:metabolism; D003711:Demyelinating Diseases / Q000150:complications / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D051767:Early Growth Response Protein 2 / Q000235:genetics / Q000378:metabolism; D004742:Enhancer Elements, Genetic; D044127:Epigenesis, Genetic; D005786:Gene Expression Regulation; D006657:Histones / Q000235:genetics / Q000378:metabolism; D008297:Male; D051379:Mice; D009186:Myelin Sheath / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D059348:Peripheral Nerve Injuries / Q000150:complications / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D016755:Proto-Oncogene Proteins c-jun / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D055757:SOXE Transcription Factors / Q000235:genetics / Q000378:metabolism; D012583:Schwann Cells / Q000378:metabolism* / Q000473:pathology; D012584:Sciatic Nerve / Q000293:injuries / Q000378:metabolism / Q000473:pathology; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D050659:Core Binding Factor Alpha 1 Subunit; D051767:Early Growth Response Protein 2; D006657:Histones; D016755:Proto-Oncogene Proteins c-jun; D055757:SOXE Transcription Factors; D014157:Transcription Factors
keywords: ChIP Sequencing (ChIP-seq); Chromatin Immunoprecipitation (ChiP); Glial Cell; Histone Modification; Neurobiology; Schwann Cells