Abstract
Glucagon-like peptide-1 (GLP-1) receptor agonists are effective hypoglycemic
agents for type 2 diabetes mellitus (T2DM). It was reported that T2DM was
implicated in pancreatic β-cell senescence. Whether loxenatide regulates
cellular senescence of pancreatic β-cells is to be investigated. Our results
revealed that high glucose (HG)-induced cellular senescence and elevated
expression of SASP factors inhibited cell proliferation and stimulated DNA
damage, which were reversed by loxenatide treatment. In addition, HG induction
resulted in promoted insulin secretion and insulin synthesis of pancreatic
β-cells and loxenatide treatment further strengthened these influences. In
addition, loxenatide could inactivate the PERK/eIF2α signaling pathway via
decreasing the levels of p-PERK and p-eIF2α in HG-induced pancreatic β-cells.
Furthermore, CCT020312, an activator of the PERK/eIF2α signaling pathway,
abolished loxenatide-mediated inhibiting cellular senescence, elevating cell
proliferation and improving DNA damage and enhancing insulin secretion of
HG-induced pancreatic β-cells. In conclusion, our results indicated that
loxenatide impeded cellular senescence, promoted cell proliferation, improved
DNA damage, enhanced insulin secretion and insulin synthesis of HG-induced
pancreatic β-cells through modulating the PERK/eIF2α signaling pathway.
Keywords
loxenatide - cellular senescence - insulin secretion - the PERK/eIF2α signaling pathway - type 2 diabetes mellitus