Figure 4.

PDX1 is involved in SIRT5-mediated pancreatic β-cell proliferation and insulin secretion. PDX1 was overexpressed in MIN6 and INS-1 cells. Following 48 h transfection, PDX1 (A) mRNA and (B) protein levels were assessed using reverse transcription quantitative polymerase chain reaction and western blotting, respectively. MIN6 and INS-1 cells were transfected with an empty plasmid vector, a SIRT5 expression plasmid or with expression plasmids containing SIRT5 and PDX1 simultaneously. Following 48 h transfection, cells were incubated with 1 or 20 mM glucose for 90 min and (C) the secretion of insulin was assessed in each group. (D) A CCK-8 assay was performed on the same groups of MIN6 and INS-1 cells, to assess the effects of SIRT5 on cell proliferation. Each experiment was repeated three times. The results are presented as the mean ± standard deviation. *P<0.05 vs. Vector and ^#P<0.05 vs. SIRT5. PDX1, pancreatic and duodenal homeobox 1; SIRT5, sirtuin 5; OD, optical density; Vector, pcDNA3.1 plasmid vector.