Identification of a potent neurotrophic substance for ciliary ganglionic neurons in fetal calf serum as insulin-like growth factor II.
When fetal calf serum (FCS) alone is used as a trophic support for cultured chicken parasympathetic ciliary ganglionic (cCG) neurons, it does not show any survival-promoting effects on these neurons. When FCS is applied to heparin-affinity chromatography, however, potent survival-promoting activity is obtained in the fraction eluted with 0.5 M NaCl. Using cCG neurons as a bioassay system, this neurotrophic activity was purified by a combination of heparin-affinity chromatography, gel filtration chromatography, and Sep-Pak C18 cartridge. The 40-50-kDa fractions from the gel filtration column with strong survival-promoting activity were shown to contain insulin-like growth factor II (IGF-II) by immunoblot analysis. By acidification, the survival-promoting activity and IGF-II were translocated together from the 40-50-kDa to the 7-10-kDa fractions, and the survival-promoting activity in the 7-10-kDa fractions was blocked by an anti-IGF-II neutralizing monoclonal antibody. These results indicate that the neurotrophic substance in 0.5 M NaCl-eluate from heparin-affinity chromatography is IGF-II and that mechanisms may exist in vivo for the activation of latent IGF-II, whose biological effects may be blocked by its specific binding proteins.
Motoike
T
T
Neuroanatomy, University of Heidelberg, Germany.
Unsicker
K
K
D000818:Animals; D000911:Antibodies, Monoclonal; D015153:Blotting, Western; D002417:Cattle; D002470:Cell Survival / Q000187:drug effects; D002642:Chick Embryo; D002846:Chromatography, Affinity; D002850:Chromatography, Gel; D020934:Ciliary Neurotrophic Factor; D004305:Dose-Response Relationship, Drug; D004815:Epidermal Growth Factor / Q000494:pharmacology; D005726:Ganglia, Parasympathetic / Q000166:cytology*; D006493:Heparin / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology; D007335:Insulin-Like Growth Factor II / Q000037:antagonists & inhibitors / Q000302:isolation & purification* / Q000494:pharmacology*; D008970:Molecular Weight; D009414:Nerve Growth Factors / Q000302:isolation & purification* / Q000494:pharmacology; D009419:Nerve Tissue Proteins / Q000494:pharmacology; D009474:Neurons / Q000166:cytology / Q000187:drug effects*; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology
D000911:Antibodies, Monoclonal; D020934:Ciliary Neurotrophic Factor; D009414:Nerve Growth Factors; D009419:Nerve Tissue Proteins; D010982:Platelet-Derived Growth Factor; D004815:Epidermal Growth Factor; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II; D006493:Heparin