FIGURE 9.

FK-506-induced beta cell death is prevented by overexpression of Npas4. MIN6 cells or dispersed mouse islet cells were infected with control virus (Ad-eGFP) or Ad-Npas4 overnight at a multiplicity of infection of 20:1 or 10:1, respectively. The medium was replaced, and cells were given a 1-day recovery period. Following 24-h treatment with vehicle (DMSO) or clinically relevant doses of FK-506 (10 or 37 nm), expression of the apoptosis marker cleaved caspase-3 was assessed via Western blot analysis and quantified using densitometry, with GAPDH as a reference and normalizing to eGFP-transduced, DMSO-treated cells. A and B, Ad-eGFP infected MIN6 had significantly increased levels of cleaved caspase-3 after treatment with 10 and 37 nm FK-506 whereas Ad-Npas4-transduced MIN6 cells did not. C and D, after 24-h treatment with vehicle or 37 nm FK-506, dispersed islet cells infected with eGFP showed increased cleaved caspase-3 expression, whereas Npas4 transduction prevented it. Error bars represent mean ± S.E., and significance was determined using a one-way ANOVA with Bonferroni's multiple comparison test and Bartlett's test for equal variances (n = 5). ***, p ≤ 0.001.