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Neurotrophic activity of interphotoreceptor matrix on human Y79 retinoblastoma cells
J Tombran-Tink1, A Li, M A Johnson
1Laboratory of Retinal Cell and Molecular Biology, National Eye Institute, National Institutes of Health, Bethesda, Maryland 20892.
Abstract:
A neurotrophic activity of adult monkey and bovine interphotoreceptor matrix (IPM) was examined by using cultured human Y79 retinoblastoma cells as a model system. The cells were stimulated for 7 days in suspension culture with soluble IPM components and then attached to poly-D-lysine substratum. IPMs from both species induced greater than 80% neuronal differentiation of Y79 cell aggregates after 11 days of attachment as adjudged morphologically by the extension of lengthy, neurite-like processes. Immunocytochemical studies indicate that differentiated Y79 cells had an increased level of expression of neuron-specific enolase and a concomitant decreased expression of glial fibrillary acidic protein. This neurotrophic activity cannot be ascribed to nerve growth factor, platelet-derived growth factor, fibroblast growth factor, epidermal growth factor, or transforming growth factor beta. Although the nature of the factor and its cellular source have yet to be characterized, it may be related to a recently described neurotrophic protein secreted by human fetal retinal pigment epithelial cells in culture. Our findings provide evidence supporting the neuroblastic potential of the Y79 cell line and indicate that the IPM contains a potent neurotrophic activity. Such factors may be important to normal differentiation and maintenance of function of the neural retina.
Insights
Interphotoreceptor matrix (IPM) from monkeys and cows promotes neuronal differentiation in cultured retinoblastoma cells. This suggests IPM contains potent neurotrophic factors crucial for retinal development and function.
Area of Science:
- Ophthalmology
- Neuroscience
- Cell Biology
Background:
- The interphotoreceptor matrix (IPM) is an extracellular matrix in the retina.
- Its role in neural differentiation is not fully understood.
- Retinoblastoma cell lines offer a model for studying neuronal development.
Purpose of the Study:
- To investigate the neurotrophic activity of adult monkey and bovine IPM.
- To determine if IPM can induce neuronal differentiation in Y79 retinoblastoma cells.
- To characterize the nature of the neurotrophic factor within IPM.
Main Methods:
- Cultured human Y79 retinoblastoma cells were stimulated with soluble IPM components.
- Cells were cultured in suspension for 7 days, then attached to a poly-D-lysine substratum.
- Morphological and immunocytochemical analyses were performed after 11 days of attachment.
Main Results:
- IPM from both monkey and bovine sources induced >80% neuronal differentiation in Y79 cells.
- Differentiated cells exhibited neurite-like processes and increased neuron-specific enolase expression.
- Glial fibrillary acidic protein expression decreased, indicating a shift away from glial differentiation.
Conclusions:
- The IPM contains a potent neurotrophic activity capable of inducing neuronal differentiation in Y79 retinoblastoma cells.
- This activity is distinct from known growth factors like NGF, PDGF, FGF, EGF, and TGF-β.
- The findings suggest IPM-derived factors are important for neural retina differentiation and function.