Human neuroblastoma cells transfected with two Chinese presenilin 1 mutations are sensitized to trophic factor withdrawal and protected by insulin-like growth factor-1.

ABSTRACT

BACKGROUND: Two novel presenilin 1 (PS1) mutations, V97L and A136G, were recently found to be involved in the early-onset of Alzheimer's disease in two Chinese families. This research aimed to verify their pathological effects. METHODS: The human neuroblastoma SH-SY5Y cells stably transfected with these two Chinese presenilin 1 mutations were established to explore whether they are sensitive to, or influenced by, serum deprivation and protected by insulin-like growth factor-1 (IGF-1). Apoptosis rate, glucose uptake of the cells and the expression of glucose transport protein 1 (GLUT1) on cell membranes were examined. RESULTS: The V97L or A136G mutants significantly decreased the cells viability and increased the apoptosis rate when compare to PS1wt and mock transfected cells. IGF-1 was found to improve the viability of these two kinds of mutant cells significantly, and to show a protective effect for the mutants when they were treated with trophic deprivation. The glucose uptake of each transfected cell line increased to about 25% after IGF-1 treatment, GLUT1 expression on the cell membrane increased modestly by about 15% - 20%. CONCLUSIONS: Enhanced sensitivity to trophic withdrawal in the cells transfected with the two Chinese PS1 mutations may contribute to the neuron apoptosis. IGF-1 provided a protective effect to cells, possibly through an enhanced glucose transport and mitochondrial activities.