Myelination of axons in the nervous system is critical for not only conduction of action potentials, but also for providing tropic support to ensure long term survival of neurons in both the central and peripheral nervous systems. Myelin disorders are a major cause of neurological disease, and can be caused by genetic disorders, infectious disease, and inflammation. Therefore, understanding the pathways that control gene expression patterns in myelinating cells is a critical step in not only elucidating developmental pathways, but also to provide insight into means by which remyelination after nerve injury can be accelerated. The genetic control of myelination has been a major focus of research, and critical transcription factors and their target gene networks have begun to be elucidated. Interestingly, recent studies have demonstrated that formation of myelin-and it longs term maintenance-depends upon not only gene activation, but also downregulation of genes that inhibit myelin formation. Although substantial progress has been made to identify gene expression changes that coordinate myelination, there have been relatively few studies examining the chromatin modifications required for myelination. For example, myelin maintenance depends upon a program of gene repression, but practically nothing is known regarding the role of histone/DNA methylation in this vital aspect of myelination. The long term objective of our laboratory is to elucidate an integrated mechanism of myelination based on critical genetic and epigenetic switches required for myelin formation and maintenance. Specifically, this proposal focuses on testing the involvement of the polycomb epigenetic pathway in peripheral nerve myelination. Chromatin immunoprecipitation analyses will be used to determine the developmental regulation of epigenetic markers in response to injury and aging. The analysis will focus on epigenetic changes that occur in gene loci that are repressed during the myelination process, and test for the first time the involvement of the polycomb pathway in formation and long term maintenance of myelin. Finally, this proposal also takes advantage of several unique aspects of peripheral nerve, which facilitate the epigenetic analysis that we have proposed here.

Public Health Relevance

Formation of the myelin sheath that insulates nerves is critical for nervous system development and for recovery of the nervous system from injury. This proposal will characterize chromatin modifications that occur are required for long term stability of myelination in vivo. The proposed analysis of epigenetic regulation will provide a genome-wide framework for elucidating how genetic pathways are coordinately regulated to achieve proper myelination.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS075269-03
Application #
8508095
Study Section
Cellular and Molecular Biology of Glia Study Section (CMBG)
Program Officer
Morris, Jill A
Project Start
2011-07-01
Project End
2016-06-30
Budget Start
2013-07-01
Budget End
2014-06-30
Support Year
3
Fiscal Year
2013
Total Cost
$336,458
Indirect Cost
$104,724
Name
University of Wisconsin Madison
Department
Biology
Type
Schools of Veterinary Medicine
DUNS #
161202122
City
Madison
State
WI
Country
United States
Zip Code
53715
Ma, Ki H; Duong, Phu; Moran, John J et al. (2018) Polycomb repression regulates Schwann cell proliferation and axon regeneration after nerve injury. Glia 66:2487-2502
Rodríguez-Molina, José F; Lopez-Anido, Camila; Ma, Ki H et al. (2017) Dual specificity phosphatase 15 regulates Erk activation in Schwann cells. J Neurochem 140:368-382
Duncan, Ian D; Bugiani, Marianna; Radcliff, Abigail B et al. (2017) A mutation in the Tubb4a gene leads to microtubule accumulation with hypomyelination and demyelination. Ann Neurol 81:690-702
Ma, Ki H; Hung, Holly A; Svaren, John (2016) Epigenomic Regulation of Schwann Cell Reprogramming in Peripheral Nerve Injury. J Neurosci 36:9135-47
Poitelon, Yannick; Lopez-Anido, Camila; Catignas, Kathleen et al. (2016) YAP and TAZ control peripheral myelination and the expression of laminin receptors in Schwann cells. Nat Neurosci 19:879-87
Lopez-Anido, Camila; Poitelon, Yannick; Gopinath, Chetna et al. (2016) Tead1 regulates the expression of Peripheral Myelin Protein 22 during Schwann cell development. Hum Mol Genet 25:3055-3069
Ma, Ki H; Svaren, John (2016) Epigenomic reprogramming in peripheral nerve injury. Neural Regen Res 11:1930-1931
Ma, Ki H; Hung, Holly A; Srinivasan, Rajini et al. (2015) Regulation of Peripheral Nerve Myelin Maintenance by Gene Repression through Polycomb Repressive Complex 2. J Neurosci 35:8640-52
Hung, Holly A; Sun, Guannan; Keles, Sunduz et al. (2015) Dynamic regulation of Schwann cell enhancers after peripheral nerve injury. J Biol Chem 290:6937-50
Lopez-Anido, Camila; Sun, Guannan; Koenning, Matthias et al. (2015) Differential Sox10 genomic occupancy in myelinating glia. Glia 63:1897-1914

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