A-064 Improved Insulin production in Advanced glycation end-products (AGEs)-induced RIN-m5F pancreatic β-cells by using a Flavonoid-Rich Medicinal Plant, Kaempferia parviflora treatment

Abstract

Background Advanced glycation end-products (AGEs) are glycated proteins that react with reducing sugar which causes the damages of function and cellular signaling of insulin production in insulinoma cells. AGEs also contribute to hyperglycemia-induced insulin resistance in type 2 diabetes. AGEs gradually form during the chronic high blood glucose condition, which is a major risk factor and harmful to β-cells function and survival, and could alter the insulin signaling and downregulate the insulin-responsive transcription factors including PDX-1, Glut-2, GCK, and Pre-INS. Kaempferia parviflora, also known as black ginger and flavonoid-rich medicinal plant, has beneficial properties for type 2 diabetes patients as a counteracts the detrimental effects of AGEs and improves the insulin production in pancreatic β-cells. Thus, we hypothesize that treated β-cells with K. parviflora, which is the most effective flavonoid-containing plant might protect against the damage of AGEs-induced insulin impairment, and these effects are also responsible for improved insulin synthesis and the essential transcription factors in pancreatic β-cells. Methods Rat pancreatic β-cell line RIN-m5F (ATCC CRL-2058) were maintained and cultured in RPMI 1640 medium containing 10% (v/v) FBS, 1% penicillin-streptomycin at 37◦C in a humidified atmosphere containing 5% CO2. RIN-m5F cells were pre-treated with the K. parviflora at concentrations 0, 25, and 50 µg/ml for 48 hours, and afterward, exposure to 250 µg/ml AGEs treatment. To quantify the bioactive compound of K. parviflora, total phenolic and flavonoid content assays were performed and the transcriptional changes of insulin-related genes (PDX-1, Glut-2, GCK, and Pre-INS) were determined by using real-time qRT-PCR. Results K. parviflora has shown a high phenolic content and flavonoid content was 50.43 ± 1.74, 26.66 ± 1.18 mg GAE/g Dry weight of sample, respectively. For the transcriptional changes of insulin-related genes, the levels of gene expression in the regulators of insulin secreting pathway (PDX-1, Glut-2, GCK, and Pre-INS) were significantly downregulated after exposure to AGEs-treated, while the pre-treatment of K. parviflora was showed statistically difference. PDX-1, Glut-2, GCK, and Pre-INS expressions were significantly upregulated after pre-treated with 50 µg/ml K. parviflora. However, under the AGEs-treated alone condition, the transcriptional levels were significantly decreased as compared to the control (untreated). Taken together, these results suggest K. parviflora could be a potential natural medicine to ameliorate the damage of insulin production in AGEs-induced β-cell damage and highlight promising alternatives for therapeutic avenue against diabetes. Conclusions Treated RIN-m5F pancreatic β-cells with K. parviflora, a flavonoid-rich medicinal plant, could upregulate the insulin-responsive transcription factors and improve the insulin production in damaging AGEs-induced pancreatic β-cells. Our findings provide a novel strategy related metabolic disease and insights into the regulation of insulin synthesis by using K. parviflora treatment as a therapeutic agent against type 2 diabetes.