Figure 6.

TGF_β1 promotes Orai1/AKT-dependent proliferation through an autocrine positive feedback loop in human-activated PSCs. (A) TGF_β1 stimulation decreased AKT phosphorylation in Orai1 knocked-down cells. Orai1 knocked-down cells were FBS-starved overnight and then stimulated 30 min with TGF_β1, 72 h post-transfection. Representative Western blot of TGF_β1 stimulation on Orai1 knocked-down mediated AKT activation (Aa) and the quantification (* p < 0.05, at least N = 3, two-way ANOVA followed by Bonferroni post hoc test, (Ab). All values were first normalized to the referent protein GAPDH and then to siCtrl non-treated with TGF_β1 condition and reported as mean ± SEM. (B,C) Involvement of TGF_β1 in PS-1 cell proliferation and survival. Transfected cells were treated 48 h with TGF_β1 (20 ng/mL) within an FBS-free medium, and the proliferation rate, as well as the mortality rate, were evaluated by Trypan blue assay, 72 h post-transfection (* p < 0.05, *** p < 0.001, NS, N = 3, one-way ANOVA followed by Bonferroni multiple comparison tests). All values were normalized to siCtrl non-treated with TGF_β1 condition and reported as mean ± SEM. Cell mortality was calculated using the formula: % of cell death = number of dead cells/number of total cells, reported as mean ± SEM for each condition.