Danzhi Jiangtang Capsule Mediates NIT-1 Insulinoma Cell Proliferation and Apoptosis by GLP-1Akt Signaling Pathway

الملخص EN

Objective.

This study aimed to investigate the effects of Danzhi Jiangtang Capsule (DJC) on the proliferation and apoptosis functions of NIT-1 pancreatic β-cells exposed to high-glucose load through GLP-1 activated Akt/ FoxO1 signaling pathway.

Methods.

Cellular apoptosis of NIT-1 pancreatic β-cells was induced by culturing in medium with 33.3mmol/L high glucose (HG).

Then low-dose DJC (HG +LD), high-dose DJC (HG +HD), high-dose DJC+ GLP-1 inhibition (HG +HD +GI), and high-dose DJC+AKT inhibition (HG +HD+AI) were added, respectively.

Cellular proliferation was accessed by cell counting kit (CCK-8) and cellular apoptosis was measured by Annexin V-FITC/PI staining.

The protein levels of phosphorylated phosphatidylinositol-3-kinase (p-PI3K), phosphorylated AKT (p-AKT), phosphorylated Forkhead box protein O1 (p-FoxO1), and cleaved caspase-3 were detected by Western blotting.

The mRNA expression of pancreatic duodenal homeobox-1 (PDX-1), CyclinD1, Bcl-2, and insulin was tested by Q-PCR.

Results.

Comparing to HG group, (HG+HD) group showed a significantly increased cellular proliferation.

The apoptosis of NIT-1 cells also was obviously reduced, with downregulated cleaved caspase-3 protein level and upregulated PDX-1, CyclinD1, and Bcl-2 mRNA levels (P<0.05).

Additionally, (HG+HD) group manifested increased insulin mRNA expression; the protein levels of p-PI3K and p-AKT were markedly increased and p-FoxO1 was decreased.

All of the above therapeutic effects by DJC intervention had been reversed by GLP-1 inhibition in (HG+HD+GI) group or AKT inhibition in (HG+HD+AI) group.

Conclusion.

DJC was able to attenuate the toxicity of high-glucose load in NIT-1 pancreatic β-cells, ascribed to the improvement of cellular proliferation and apoptosis by GLP-1/Akt signaling pathway.

This study could supply a new mechanism of DJC effects on type 2 diabetes mellitus (T2DM) treatment.