Fig 1: The effect of vasoactive intestinal peptide (VIP) on the phosphorylation of PTEN and PI3K/AKT in Splenic lymphocyte cells (SPLCs). (A) SPLCs were isolated from the nonobese diabetic (NOD) mice and plated for 12 or 24 h with different doses of VIP. A CCK-8 assay was used to detect the optical density (OD) value of each group. The data were analyzed by a mixed-effects model approach with Geisser-Greenhouse correction. Tukey's multiple comparisons post hoc test was conducted following analysis of variance (ANOVA). (B) SPLCs were transfected with 5 pM mpten931 (siRNA targeting PTEN). At 24 h post-transfection, the knockdown efficiency of mpten931 was determined by qRT-PCR. (C) Cells were treated with 125 ng/µL VIP for the indicated times at 24 h post-transfection. The data were analyzed with one-way ANOVA. (D) Representative WB experiments. Cells were transfected or not with mpten931 followed by treatment with 0 or 125 ng/µL VIP for 12 h. (E–G) Protein expression levels of total AKT, phosphorylated AKT, total PI3K, phosphorylated PI3K, and phosphorylated PTEN were analyzed by Western immunoblotting (WB). Cumulative data from three independent experiments. *p < 0.05, **p < 0.01.