Vanadium Induces Autophagy Via Endoplasmic Reticulum Stress-mediated PERK/ATF4/CHOP Signaling Pathway In Duck Renal Tubular Epithelial Cells

The study aims to investigate the regulatory relationship between endoplasmic reticulum（ER）stress-mediated PERK/ATF4/CHOP signaling pathway and autophagy in the mechanism of vanadium-induced nephrotoxicity in ducks.In this experiment,the primary duck renal tubular epithelial cells were used as the research object,and sodium metavanadate（Na VO₃）was used as the vanadium（V）source to construct an in vitro model of V exposure.Experimental methods such as transmission electron microscopy,flow cytometry,immunofluorescence,western blot,and real-time fluorescence quantification were used to detect the morphology of the ER,intracellular Ca²⁺concentration,the number of autophagosomes and acidic vesicular organelles（AVOs）,and related m RNA and protein levels to evaluate the ER stress and autophagy.At the same time,PERK inhibitor（GSK,1μM）and autophagy inhibitor（chloroquine,50μM）were selected to explore the relationship between PERK/ATF4/CHOP signaling pathway of ER stress and autophagy.The results showed that exposure to V caused the dilatation and swelling of the ER and intracellular calcium overload,and upregulated PERK,e IF2α,ATF4 and CHOP m RNA levels and p-PERK and CHOP protein levels associated with ER stress in cells（P<0.05）.Additionally,excess V markedly increased the number of autophagosomes,AVOs and LC3puncta,as well as the m RNA levels of Beclin1,Atg5,Atg12,LC3A and LC3B and protein levels of Beclin1,Atg5 and LC3B-II/LC3B-I,but decreased the m RNA and protein levels of p62（P<0.05）.However,the combination of PERK inhibitor and V significantly alleviated the changes in autophagy-related factors induced by V,while the combination of autophagy inhibitor and V significantly exacerbated the changes in endoplasmic reticulum stress-related factors induced by V（P<0.05）.In conclusion,excessive V could induce ER stress and autophagy in duck renal tubular epithelial cells.ER stress might promote V-induced autophagy via the PERK/ATF4/CHOP signaling pathway,and inhibition of autophagy may aggravate V-induced ER stress.