RRC ID 1854
Author Martinet W, De Meyer GR, Andries L, Herman AG, Kockx MM.
Title In situ detection of starvation-induced autophagy.
Journal J. Histochem. Cytochem.
Abstract Autophagy is a regulated bulk degradation process involved in many different human pathologies. Transmission electron microscopy (TEM) is currently the only reliable method for monitoring autophagy in situ. Because TEM is labor intensive, we questioned whether useful marker proteins can be found for unambiguous detection of autophagy in tissue via routinely used colorimetric, immunohistochemical, or fluorescent techniques. Starved HepG2 hepatocytes and nutrient deprived liver tissue were used as a model for the initiation of autophagy. Our findings indicate that starvation-induced autophagy in HepG2 cells was associated neither with differential mRNA gene expression nor with changes in the expression level of known autophagy-related proteins. On the contrary, both transcription and translation were inhibited, suggesting that the identification of autophagy-specific biomarkers for tissue is highly compromised. Light chain 3 (LC3) protein, which is an attractive marker of autophagosomes, revealed a relatively low expression level in tissue and cultured cells, but could be detected via immunohistochemistry in liver from GFP-LC3 transgenic mice. The number of LC3 immunopositive dot-like structures was significantly upregulated in liver tissue from nutrient-deprived GFP-LC3 mice as compared with nonstarved control tissue. Our results suggest that LC3 immunostaining can be used as an alternative detection method for autophagy in situ, but only when this protein is overexpressed.
Volume 54(1)
Pages 85-96
Published 2006-1
DOI 10.1369/jhc.5A6743.2005
PII jhc.5A6743.2005
PMID 16148314
MeSH Animals Autophagy* Biomarkers / metabolism Cell Line, Tumor Hepatocytes / cytology* Hepatocytes / metabolism Hepatocytes / ultrastructure Humans Immunohistochemistry Liver / cytology* Liver / metabolism Liver / ultrastructure Mice Mice, Inbred C57BL Mice, Transgenic Microtubule-Associated Proteins / genetics Microtubule-Associated Proteins / metabolism Oligonucleotide Array Sequence Analysis Proteome / genetics Proteome / metabolism* RNA, Messenger / metabolism Rats Reverse Transcriptase Polymerase Chain Reaction Starvation* Up-Regulation
IF 2.816
Times Cited 91
Mice GFP-LC3#53