Effect of nicotinamide mononucleotide on insulin secretion and gene expressions of PDX-1 and FoxO1 in RIN-n5f cells / 中南大学学报(医学版)

ABSTRACT

Objective To investigate the effect of nicotinamide mononucleotide (NMN) on insulin secretion and gene expressions of pancreatic and duodenal homeobox 1 ( PDX-1 ) and forkhead box-containing protein O-1 ( FoxO1 ),which were important transcription factors for insulin secretion.Methods Insulin secretion level in RIN-m5f cells was detected by rat insulin ELISA detection kit.The mRNA expression levels of PDX-1 and FoxO1 in RIN-m5f cells were analyzed by real-time PCR.The protein expression of PDX-1 was measured by Western blot.Results Insulin secretion levels in RIN-m5f cells treated with repaglinide ( 10 nmol/L) plus NMN ( 100 μnol/L) was significantly higher than those in the blank control,the DMSO control group,and the NMN (50μmol/L) treated group (P ＜0.05 ).The mRNA expression levels of PDX-1 in RIN-m5f cells treated with NMN ( 10,50 and 100 μmol/L) for 36 h were significantly higher than those in the control group (P ＜0.05,P ＜ 0.01,and P ＜ 0.001,respectively).There was marked differences in the mRNA expression levels of PDX-1 among different concentrations of NMN (P ＜0.001 ),but no significant differences in the mRNA expression level of FoxO1 ( P ＞ 0.05).No significant difference was found in the protein expression levels of PDX-1 in RIN-m5f cells treated by NMN (50,100,and 200 μmol/L) for 36 or 48 h compared with the control group (P ＞ 0.05).Conclusion NMN can stimulate insulin secretion and upregulate the mRNA expression of PDX-1 in RIN-m5f cells.