Insulin-like growth factor binding protein-1 is pre-synaptic at mouse neuromuscular synapses and is transported in nerve
In a previous study, we localized insulin-like growth factor binding protein 1 (IGFBP-1) to mouse neuromuscular junctions, and intramuscular nerves. To determine if pre-synaptic accumulation of IGFBP-1 occurred, we used double ligation of sciatic nerve in adult mice at different time points. IGFBPs were deteced by Western ligand blot (WLB) with125I-IGF-I. WLB and Western immunoblot (WIB) analysis of extracts from double-ligated nerves showed a delayed (6 days) increase of IGFBP-1 in the soluble fraction between the ligatures and distal to the distal ligature. For comparison we evaluated transport of neurofilament components, using WIB and confirmed the primarily anterograde transport of these intraaxonal proteins. These data suggest that expression of IGFBP-1 is both by activated Schwann cells as well as retrograde axonal transport with likely entry into the axon at the synapse.
Key WordsNeurotrophic paracrine regeneration nerve muscle ligation transport diabetes neuropathy ALS
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- 2.Baskin, D. G., Wilcox, B. J., Figlewitz, D. P., Dorsa, D. M. 1988. Insulin and insulin-like growth factors in the CNS. Trends Neurosci. 11:608–612.Google Scholar
- 4.Blum, W. F., Jenne, E. W., Reppin, F., Kietzmann, K., Ranke, M. B. and Bierich, J. R. 1989. Insulin-like growth factor I (IGF-I)-binding protein complex is a better mitogen than free IGF-I. Endocrinol. 25:766–772.Google Scholar
- 5.McGuire, W. L., Jr., Jackson, J. G., Figueroa, J. A., Shimasaki, S., Powell, D. R. and Yee, D. 1992. Regulation of Insulin-like growth factor-binding protein (IGFBP) expression by breast cancer cells: use of IGFBP-1 as an inhibitor of insulin-like growth factor action. J. National Cancer Institute 84:1336–1341.Google Scholar
- 10.Hantaï, D., Rao, S. J., and Festoff, B. W. 1990. Rapid neural regulation of muscle urokinase-like plasminogen activator as defined by nerve crush. Pro. Natl. Acad. Sci. 87:2926–2930.Google Scholar
- 12.Laemmli, U. K. 1970. Cleavage of structural proteins during the assembly of the head of bacteriophage T4. Nature (Lond.) 227:680–685.Google Scholar
- 13.Hossenlopp, P., Seurin, D., Segovia-Quinson, B., Hardouin, S., and Binoux, M. 1986. Analysis of serum insulin-like growth factor binding proteins using Western Blotting: Use of the method for titration of the binding proteins and competitive binding studies. Anal. Biochem. 154:138–143.PubMedGoogle Scholar
- 16.Wu, J. S., Hogan, G. R., and Morris, J. D. 1985. Modified methods for preparation of cryostal sections of skeletal muscle. Muscle & Nerve, 8:664–666.Google Scholar
- 20.Ocrant, I., Fay, C. T., and Pormelee, J. T. 1990. Characterization of insulin-like growth factor binding protein produced in rat central nervous system. Endocrinol. 127:1260–1267.Google Scholar
- 26.Oyler, G. A., Higgins, G. A., Hart, R. A., Battenberg, E., Billingsley, M., Bloom, F. E., and Wilson, M. C. 1989. The identification of a novel synaptosomal-associated protein SNAP-25, differentially expressed by neuronal subpopulations. J. Cell Biology 109:3039–52.Google Scholar