TY - JOUR
T1 - Cerebellar neurons lacking complex gangliosides degenerate in the presence of depolarizing levels of potassium
AU - Wu, G.
AU - Xie, X.
AU - Lu, Z. H.
AU - Ledeen, R. W.
PY - 2001/1/2
Y1 - 2001/1/2
N2 - Mice engineered to lack GM2/GD2 synthase (GalNAc-T), with resultant deficit of GM2, GD2, and all gangliotetraose gangliosides, were originally described as showing a relatively normal phenotype with only a slight reduction in nerve conduction. However, a subsequent study showed that similar animals suffer axonal degeneration, myelination defects, and impaired motor coordination. We have examined the behavior of cerebellar granule neurons from these neonatal knockouts in culture and have found evidence of impaired capacity for Ca2+ regulation. These cells showed relatively normal behavior when grown in the presence of physiological or moderately elevated K+ but gradually degenerated in the presence of high K+. This degeneration in depolarizing medium was accompanied by progressive elevation of intracellular calcium and onset of apoptosis, phenomena not observed with normal cells. No differences were detected in cells from normal vs. heterozygous mice. These findings suggest that neurons from Gal-NAc-T knockout mice are lacking a calcium regulatory mechanism that is modulated by one or more of the deleted gangliosides, and they support the hypothesis that maintenance of calcium homeostasis is one function of complex gangliosides during, and perhaps subsequent to, neuronal development.
AB - Mice engineered to lack GM2/GD2 synthase (GalNAc-T), with resultant deficit of GM2, GD2, and all gangliotetraose gangliosides, were originally described as showing a relatively normal phenotype with only a slight reduction in nerve conduction. However, a subsequent study showed that similar animals suffer axonal degeneration, myelination defects, and impaired motor coordination. We have examined the behavior of cerebellar granule neurons from these neonatal knockouts in culture and have found evidence of impaired capacity for Ca2+ regulation. These cells showed relatively normal behavior when grown in the presence of physiological or moderately elevated K+ but gradually degenerated in the presence of high K+. This degeneration in depolarizing medium was accompanied by progressive elevation of intracellular calcium and onset of apoptosis, phenomena not observed with normal cells. No differences were detected in cells from normal vs. heterozygous mice. These findings suggest that neurons from Gal-NAc-T knockout mice are lacking a calcium regulatory mechanism that is modulated by one or more of the deleted gangliosides, and they support the hypothesis that maintenance of calcium homeostasis is one function of complex gangliosides during, and perhaps subsequent to, neuronal development.
KW - Cerebellar granule neurons
KW - GM1 ganglioside
KW - Ganglioside-deficient neurons
KW - Intracellular calcium
KW - Neuritogenesis
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U2 - 10.1073/pnas.98.1.307
DO - 10.1073/pnas.98.1.307
M3 - Article
C2 - 11134519
AN - SCOPUS:0035793084
SN - 0027-8424
VL - 98
SP - 307
EP - 312
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 1
ER -