GM1 ganglioside treatment of PC12 cells stimulates ganglioside, glycolipid, and lipid, but not glycoprotein synthesis independently from the effects of nerve growth factor.
The incorporation of radioactive precursors into gangliosides and other glycolipids, glycoproteins, and total lipids has been studied in rat pheochromocytoma PC12 cells. Starting with the same PC12 cell pool, cultures displaying different degrees of neuritic expression in response to nerve growth factor (NGF) and combinations of serum ganglioside GM1 were produced. Attempts were then made to correlate neuritic regulation with biochemical performances of these cells. NGF stimulates the incorporation of [3H]galactose into gangliosides and other glycolipids and glycoproteins and [14C]acetate into total lipids, regardless of the serum concentration. NGF both increased their initial labeling rates and promoted additional and more extensive labeling from culture day 4 onward. Unexpectedly, exogenous GM1 also elicited an increase in ganglioside labeling as well as that of the other lipid classes, but not of glycoproteins. The GM1-induced increase was evident at higher serum concentrations (1%) regardless of the presence or absence of NGF, but not apparent in low (0.15%) serum. Serum levels themselves did not affect labeling patterns in the absence of NGF and GM1. GM1-induced stimulation of labeling reflects an increase in the synthetic activities of the cells, and not increased precursor uptake or reduced product degradation. For all constituents stimulated by GM1, concurrent treatment with NGF produces cumulative effects, suggesting independent mechanisms of action by the two molecules.
D000085:Acetates / Q000378:metabolism; D019342:Acetic Acid; D000310:Adrenal Gland Neoplasms / Q000378:metabolism*; D000818:Animals; D002455:Cell Division; D002460:Cell Line; D004305:Dose-Response Relationship, Drug; D005677:G(M1) Ganglioside / Q000494:pharmacology*; D005690:Galactose / Q000378:metabolism; D005732:Gangliosides / Q000096:biosynthesis; D006017:Glycolipids / Q000096:biosynthesis; D008055:Lipids / Q000096:biosynthesis; D008297:Male; D051379:Mice; D009414:Nerve Growth Factors / Q000494:pharmacology*; D010673:Pheochromocytoma / Q000378:metabolism*; D013997:Time Factors
D000085:Acetates; D005732:Gangliosides; D006017:Glycolipids; D008055:Lipids; D009414:Nerve Growth Factors; D005677:G(M1) Ganglioside; D019342:Acetic Acid; D005690:Galactose