Changes and significance of autophagy in hypoxic intestinal epithelial cells

CHEN Gang; SUN Chun-hong; YAN Bai-gang

Abstract：Objective To study the changes of autophagy in intestinal epithelial cells under hypoxic condi-tion.Methods The cultured human intestinal epithelial cell lines Caco-2 were divided into normoxia group ( nor-mal control group) and hypoxia group.In the hypoxia group,cells were exposed to hypoxia for 0.5,1,2,6, 12 and 24 hours,respectively.The protein expression of Beclin1,mircrotublue-assoliated protein 1 light chain 3( LC3) and P62 was assayed by Western blotting.The cellular autophagy lysosomals were detected by transmission electron mi-croscopy.GFP-LC3B fusion protein was employed to visualize autophagosome formation in intestinal epithelial cells.Results The protein expression of both Beclin1 and LC3 began to increase at 0.5h in hypoxic intestinal epi-thelial cells when compared with those in normal control group,peaked at 12h,and was still higher than those in nor-mal control group at 24h.The expression of P62 decreased gradually after hypoxia,with the lowest at 24h.Under transmission electron microscopy, it was observed that the number of autophagy lysosomal increased significantly in hy-poxic intestinal epithelial cells.GFP-LC3B fusion protein tracer also showed that autophagosome formation was quite evident in hypoxic intestinal epithelial cells.Conclusion The autophagy in intestinal epithelial cells is significantly enhanced by hypoxia and may contribute to the regulation of hypoxia-induced damage in intestinal epithelial cells.