Figure 2

SFC reduces palmitate (PA)-induced lipotoxicity in HepG2 hepatocytes. (a) SFC reduces PA-induced lipid accumulation in HepG2 cells. HepG2 cells were exposed on 0.1 mM PA for 24 hrs in the presence or absence of 0.2 mM SFC, and the intracellular lipid was then observed by Nile Red staining (540 as excitation and 630 as emission). TG per 1 μg of cellular protein was quantified by using TG assay kit. ***p < 0.001 vs. PA-untreated cells. ^###p < 0.001 vs. PA-treated cells. (b) Viability reduction by PA treatment (0.3 mM, 15 h) in HepG2 cells and protective effect of SFC on the viability reduction was determined by MTT viability assay. **p < 0.01 vs. PA-untreated cells. ^##p < 0.01; ^###p < 0.001 vs. PA-treated cells. (c) Cell death by PA treatment (0.3 mM, 15 hrs) in HepG2 cells and protective effect of SFC on cell death was determined by Cell Death Detection enzyme-linked immunosorbent assay. **p < 0.01 vs. PA-untreated cells. ^##p < 0.01; ^###p < 0.001 vs. PA-treated cells. (d) Cell death was determined by measuring level of cleaved caspase 3 in immunoblotting. ***p < 0.001 vs. PA-untreated cells. ^##p < 0.01; ^###p < 0.001 vs. PA-treated cells. Full-length blots are included in Supplementary Fig. 4 of Supplementary Information (SI). (e) Stress and inflammatory signal activation by PA treatment (0.3 mM, 12 h) and protective effect of SFC on the activation were determined by measuring levels of phospho-N-terminal C-JUN kinase (p-JNK) and phospho-P65 subunit of NFkB (p-p65) in immunoblotting. **p < 0.01 vs. PA-untreated cells. ^##p < 0.01; ^###p < 0.001 vs. PA-treated cells. Full-length blots are included in Supplementary Fig. 5 of SI. (f) Insulin resistance by PA treatment and protective effect of SFC on the insulin resistance were determined by measuring levels of phospho-protein kinase B (p-AKT) and phospho-glycogen synthase kinase 3b (p-GSK3b) in immunoblotting after 30 min insulin stimulation. **p < 0.01; ***p < 0.01 vs. insulin-unstimulated cells. ^##p < 0.01; ^###p < 0.001 vs. insulin-stimulated and PA-untreated cells. ^$$p < 0.01 vs. insulin-stimulated and PA-treated cells. Full-length blots are included in Supplementary Fig. 6. (g) Inflammatory gene induction by PA treatment and preventive effect of SFC on the induction were determined by real-time PCR. *p < 0.05; ***p < 0.001 vs. PA-untreated cells. ^##p < 0.01 vs. PA-treated cells.