GM2 promotes ciliary neurotrophic factor-dependent rescue of immortalized motor neuron-like cell (NSC-34)

We have examined whether ciliary neurotrophic factor (CNTF) can alter serum-free cell survival of immortalized motor neuron-like cells, which were established by fusing mouse neuroblastoma N18TG2 with mouse motor neurons. One of the cell lines, NSC-34 exhibited cell survival in the presence of CNTF. NSC-34 preserves the most characteristics of motor neurons, such as the formation of neuromuscular junctions on co-cultured myotube. GM2 ganglioside is characteristic of motor neurons, and expressed highly in NSC-34. When NSC-34 was cultured with exogenous GM2 ganglioside and CNTF, GM2 facilitated the cell survival effect of CNTF. In the addition, beta 1,4 N-acetylgalactosaminyltransferase (GM2 synthase) activity was enhanced up to 3.9-fold by culture in the presence of CNTF. GM2 might be a functional modulator of CNTF in motor neurons. It might be presented to cell surface by its enzyme activation, and become a signal of early stage, when CNTF rescues motor neurons.