During development, mammalian neurons can extend long axonal process, but with maturation, lose the capacity to express this growth within the central nervous system (CNS). Consequently, when severed, adult CNS axons fail to regenerate resulting in permanent dysfunction. Most recent work has focused on the possibility that glia mature so as to prevent the regeneration of CNS axons. In contrast, these proposed studies will explore the possibility that neurons themselves mature so as to become unable to grow within the CNS environment even though they retain considerable intrinsic capacity for growth. This possibility is supported by preliminary evidence showing that with maturation axons undergo several functional and molecular changes that likely compromise their ability to grow within a glial environment. - The proposed studies make extensive use of the in vitro retinal explant system developed in this laboratory to elicit regenerative growth of adult optic axons in tissue culture. This system will be used to compare the cellular function and molecular constitution of regenerating adult optic axons with growing embryonic axons. Three areas relevant to regeneration will be investigated. The first is cell surface molecules involved in the regulation neurite growth on astrocytes. Specifically, the presence and function of integrins, N-cadherin, N-CAM and Thy-1 will be compared in adult and embryonic optic fibers. The second area is intracellular molecules that are associated with and thought to be required for axons growth. One in particular, GAP-43, will be assayed for its expression in adult axons and for possible down-regulation by glia. The third area is cellular interactions between optic fibers and glia. The possibility will be tested that adult optic axons, in marked contrast to embryonic axons, are deficient in their ability to grow over astroglia in culture. Initial characterization of the basis of this differential interaction will be explored. These studies will identify differences between adult and embryonic growing axons that are important for understanding regenerative failure in the adult CNS and for developing future therapies for promoting axonal regeneration.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS026750-06
Application #
2266081
Study Section
Neurology B Subcommittee 2 (NEUB)
Program Officer
Chiu, Arlene Y
Project Start
1988-12-01
Project End
1998-12-31
Budget Start
1996-01-01
Budget End
1998-12-31
Support Year
6
Fiscal Year
1996
Total Cost
Indirect Cost
Name
University of California Irvine
Department
Anatomy/Cell Biology
Type
Schools of Arts and Sciences
DUNS #
161202122
City
Irvine
State
CA
Country
United States
Zip Code
92697
Miotke, Jill A; MacLennan, A John; Meyer, Ronald L (2007) Immunohistochemical localization of CNTFRalpha in adult mouse retina and optic nerve following intraorbital nerve crush: evidence for the axonal loss of a trophic factor receptor after injury. J Comp Neurol 500:384-400
Becker, C G; Becker, T; Meyer, R L (2001) Increased NCAM-180 immunoreactivity and maintenance of L1 immunoreactivity in injured optic fibers of adult mice. Exp Neurol 169:438-48
Becker, T; Anliker, B; Becker, C G et al. (2000) Tenascin-R inhibits regrowth of optic fibers in vitro and persists in the optic nerve of mice after injury. Glia 29:330-46
Becker, C G; Becker, T; Meyer, R L et al. (1999) Tenascin-R inhibits the growth of optic fibers in vitro but is rapidly eliminated during nerve regeneration in the salamander Pleurodeles waltl. J Neurosci 19:813-27
Bates, C A; Becker, C G; Miotke, J A et al. (1999) Expression of polysialylated NCAM but not L1 or N-cadherin by regenerating adult mouse optic fibers in vitro. Exp Neurol 155:128-39
Bates, C A; Meyer, R L (1997) The neurite-promoting effect of laminin is mediated by different mechanisms in embryonic and adult regenerating mouse optic axons in vitro. Dev Biol 181:91-101
Bates, C A; Meyer, R L (1996) Heterotrimeric G protein activation rapidly inhibits outgrowth of optic axons from adult and embryonic mouse, and goldfish retinal explants. Brain Res 714:65-75
Bates, C A; Meyer, R L (1994) Differential effect of serum on laminin-dependent outgrowth of embryonic and adult mouse optic axons in vitro. Exp Neurol 125:99-105
Meyer, R L; Miotke, J A; Benowitz, L I (1994) Injury induced expression of growth-associated protein-43 in adult mouse retinal ganglion cells in vitro. Neuroscience 63:591-602
Bates, C A; Trinh, N; Meyer, R L (1993) Distribution of microtubule-associated proteins (MAPs) in adult and embryonic mouse retinal explants: presence of the embryonic map, MAP5/1B, in regenerating adult retinal axons. Dev Biol 155:533-44

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