Glia are thought to play an important role in determining the success or failure of axonal growth. For example, primitive glia in the developing nervous system are believed to guide growing axons and assist in neuronal migrations. In contrast, astroglia found at sites of injury in mammalian adult brain are thought to retard or inhibit axonal regeneration. The factors which regulate glial support of neurons are poorly understood. We have recently identified Interleukin-1 (IL-1) as a potent mitogen for astroglia. IL-1 is a pluripotent growth factor, released by mononuclear phagocytes, which affects the inflammatory process. Our findings show that IL-1 levels in the brain are elevated following injury or during early development, and suggest an important regulatory relationship between brain IL-1 and astroglia. We believe that release of IL-1 helps to control the proliferation, growth and differentiation of astroglia in the developing and injured CNS. We propose to characterize the role of IL-1 in the developing brain by measuring the IL-1 levels during embryogenesis, by identifying cells that secrete IL-1, by monitoring growth effects of IL-1 upon embryonic brain glia in vitro, and by monitoring glial growth in vivo in developing brain after IL-1 injections. We will investigate the significance of IL-1 in the brain during injury and disease by measuring IL-1 production after brain infarction, by measuring IL-1 production after axonal degeneration, by measuring IL-1 production after brain inflammation, and by monitoring glial growth in vivo in adult brain after IL-1 injections. We will also examine in vitro the effects of IL-1 upon glia by monitoring protease production in astroglia, by monitoring effects of IL-1 upon glial cells, and by screening for IL-1 dependent astroglial cell lines. If astroglia do in fact mediate neuronal development and axonal growth, peptides that control astroglial populations become clinically important. Therapies to accelerate axonal outgrowth or reduce glial scarring might arise from IL-1 related research.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
1R01NS023113-01A1
Application #
3406258
Study Section
Neurological Sciences Subcommittee 1 (NLS)
Project Start
1986-07-01
Project End
1989-06-30
Budget Start
1986-07-01
Budget End
1987-06-30
Support Year
1
Fiscal Year
1986
Total Cost
Indirect Cost
Name
Baylor College of Medicine
Department
Type
Schools of Medicine
DUNS #
074615394
City
Houston
State
TX
Country
United States
Zip Code
77030
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Giulian, D; Li, J; Li, X et al. (1994) The impact of microglia-derived cytokines upon gliosis in the CNS. Dev Neurosci 16:128-36
Giulian, D; Corpuz, M (1993) Microglial secretion products and their impact on the nervous system. Adv Neurol 59:315-20
Vaca, K; Wendt, E (1992) Divergent effects of astroglial and microglial secretions on neuron growth and survival. Exp Neurol 118:62-72
Giulian, D; Ingeman, J E (1988) Colony-stimulating factors as promoters of ameboid microglia. J Neurosci 8:4707-17
Giulian, D; Woodward, J; Young, D G et al. (1988) Interleukin-1 injected into mammalian brain stimulates astrogliosis and neovascularization. J Neurosci 8:2485-90
Giulian, D; Young, D G; Woodward, J et al. (1988) Interleukin-1 is an astroglial growth factor in the developing brain. J Neurosci 8:709-14
Lachman, L B; Brown, D C; Dinarello, C A (1987) Growth-promoting effect of recombinant interleukin 1 and tumor necrosis factor for a human astrocytoma cell line. J Immunol 138:2913-6
Giulian, D (1987) Ameboid microglia as effectors of inflammation in the central nervous system. J Neurosci Res 18:155-71, 132-3

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