Nicotinic receptor-induced apoptotic cell death of hippocampal progenitor cells - PubMed (original) (raw)

Nicotine induces apoptosis in undifferentiated HC2S2 cells. The effect of treatment with 0.5 μ

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nicotine for 12 hr on the survival of undifferentiated HC2S2 cells was examined by the following methods. A, DNA laddering. DNA was extracted from cells 12 hr after no treatment (Con) or after treatment with 0.5 μ

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nicotine (Nic 0.5), 50 μ

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nicotine (Nic 50), or 0.5 μ

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nicotine in the presence of 100 n

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α-Bgt (Nic +Bgt). Nicotine-induced DNA fragmentation characteristic of apoptosis was seen in undifferentiated HC2S2 cells and was prevented by pretreatment with α-Bgt. The arrow shows the position of the 247 bp DNA marker. B, Fluorescence and immunocytochemistry. Nicotine-induced cell death in undifferentiated HC2S2 cells is apoptotic as seen by nuclear fragmentation (arrow) visualized by staining undifferentiated cells with DAPI 12 hr after exposure to 0.5 μ

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nicotine (bottom panel). Immunofluorescence on the same field of cells indicates the induction of p53 (red) and p21 (green) or p53 and p21 (yellow) expression (top panel). In the presence of bungarotoxin, neither nuclear fragmentation nor the induction of p53/p21 is seen (insets). Scale bar, 25 μm. C, Western blotting. Western blots of untreated cells (lane 1,C), cells treated with 0.5 μ

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nicotine in the presence of 100 n

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α-Bgt (lane 2,N + Bgt) or with nicotine alone at 0.5 μ

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(lane 3, N) revealed the induction of both p53 and p21 proteins by nicotine. No induction was observed in control cells or in cells treated with nicotine in the presence of α-Bgt. In differentiated HC2S2 cells (lanes 4, 5) no p53 signal was seen in either control (lane 4, C) or in cells treated with 0.5 μ

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nicotine (lane 5,N). Differentiated cells showed endogenous levels of p21 under both conditions and in a manner independent of the expression of p53. All lanes were probed with an actin antibody to estimate the approximate amounts loaded.