Mitochondrial Dysfunction and Autophagy in Hepatic Ischemia/Reperfusion Injury

Figure 3

Autophagy in primary mouse hepatocytes. (a) Confocal microscopy with green fluorescent protein-labeled microtubule-associated protein 1 light chain 3 (GFP-LC3) and TMRM in normoxic hepatocytes. Under the basal condition of normoxia, GFP-LC3 predominantly localizes in the cytosol. After autophagy induction, hepatocytes show numerous punctate GFP-LC3, indicative of autophagosomes. Note that some red fluorescing mitochondria are entrapped by GFP-LC3, an event signifying the onset of mitophagy. The bottom panels represent magnified images of the square inserts at the top panels. (b) Loss of autophagy after I/R. Hepatocytes were labeled with GFP-LC3 and subjected to 4 hours of simulated ischemia. After 5 minutes of reperfusion, some autophagosomes (green fluorescing punctate structures) were evident but unable to sequester abnormal mitochondria (top panels). This cell was dead after 17 minutes, as indicated by PI labeling in the nuclei (yellow arrows). In striking contrast, when autophagy was stimulated prior to ischemia, hepatocytes executed a robust autophagy to clear abnormal mitochondria and remained viable after 2 hours of reperfusion. Empty arrows display the autophagosomes surrounding the mitochondria.

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