Objective: To study the effects of cadmium on autophagy in germ cells (GC-2 spd cells) through Ca2+ and IRE1 pathway.
Methods: The viability of GC-2 spd cells was determined using a CCK-8 assay to establish the concentration of cadmium treating . MDC staining was employed to assess autophagosome formation. Laser confocal microscopy and flow cytometry were utilized to measure cytoplasmic and endoplasmic reticulum (ER) Ca2+ levels. Western blot was conducted to evaluate the expression levels of proteins associated with the IRE1 signaling pathway and autophagy.
Results: As the concentration of cadmium increased, cell viability gradually decreased. The concentrations of cadmium were determined to be 2.5, 5, and 10 μmol/L. Compared with the control group, the IOD values of MDC fluorescence intensity within the cadmium group were all elevated (P<0.05), accompanied by elevated ratios of autophagy markers LC3-II/LC3-I and up-regulation of Beclin-1 protein expression (P<0.05). Cytoplasm Ca2+ levels gradually increased, while ER Ca2+ levels decreased (P<0.05). The expression of IP3R protein, the ER Ca2+ release pathway, was up-regulated (P<0.05). Additionally, the expressions of IRE1, XBP1s, CHOP, and GRP78 were up-regulated in the cadmium group (P<0.05).
Conclusion: Cadmium exposure can induce dysregulation of calcium homeostasis in GC-2spd cells, activates the ER stress-induced IRE1 signaling pathway, and ultimately induces the occurrence of autophagy in GC-2spd cells.
Keywords: cadmium; GC-2 spd cells; calcium; inositol requiring enzyme; autophagy.