| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2004: ¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 2003: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Research Abstract |
Cell-cell and cell-matrix interactions provide essential information for controlling cell fate in terms of migration, growth, death, and differentiation. Cell surface receptors are instrumental in coordinating these interactions between cells and their microenvironment, which induces growth factors, hormones, and extracellular matrix components. In the developing nervous system, extending axons are directed toward their appropriate targets by a myriad of attractive and repulsive guidance molecules. Semaphorins are a large family of secreted and membrane-associated molecules with widespread expression during development, especially in axonal guidance, fasciculation, branching and synapse formation. Sema3A, the vertebrate secreted semaphorin, binds to neuropilin-1, which together with plexins constitutes the functional receptor.
In an attempt to investigate the role of target cells for the differentiation of nerve cells, we have co-cultured NG108cells with vascular smooth muscle cells (SM
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-3). The outgrowth of nerve fibers was promoted, but their growth cones were repelled by SM-3 cells. DNA microarray, to analyze factors involved in these phenomena, indicated that NG108cells up-regulated several characteristic genes, related in cell survival and growth, but also cytoskeletons, axonal transports and repulsive receptors for adhesion. Neuropilin-1 was one of the most characteristic up-regulated molecules. To investigate whether Sema3A and neuropilln-1 are involved in such repulsion as NG108cells showed toward SM-3cells, we confirmed protein expressions with polyclonal antibodys against neuropilin-1 or Sema3A. Westernblotting and immunochemical analysis indicated that NG108cells stably expressed neuropilin-1 in regardless with SM-3cells, but that SM-3cells didn't Sema3A. Our results suggest that SM-3cells promote NG108cells to change neuronal phenotype, and the possibility is indicated that neuropilin-1 is related in neuronal differentiation, but the repulsion observed in this co-culture system may occurred by other diffusible protein and/or adhesion molecules. Less
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