In addition to the currently available lysosomotropic drugs and autophagy whole-body knockout mouse models, we provide alternative methods that enable the modulation and detection of autophagic flux in vivo, discussing advantages and disadvantages of each method.
With the autophagosome–lysosome fusion inhibitor colchicine in skeletal muscle and temporal downregulation of autophagy using a novel Autophagy related 5-short hairpin RNA (Atg5-shRNA) mouse model we mention two models that directly modulate autophagy flux in vivo. Furthermore, methods to quantify autophagy flux, such as mitophagy transgenic reporters, in situ immunofluorescent staining and multispectral imaging flow cytometry, in mature skeletal muscle and cells are addressed.
To achieve clinical benefit, less toxic, temporary and cell-type-specific modulation of autophagy should be pursued further. A temporary knockdown as described for the Atg5-shRNA mice could provide a first insight into possible implications of autophagy inhibition. However, it is also important to take a closer look into the methods to evaluate autophagy after harvesting the tissue. In particular caution is required when experimental conditions can influence the final measurement and this should be pretested carefully.
aDepartment of Molecular Toxicology, German Institute of Human Nutrition Potsdam-Rehbruecke (DIfE), Nuthetal
bGerman Center for Diabetes Research (DZD), Munich
cInstitute of Nutrition, University of Potsdam, Nuthetal
dDZHK (German Centre of Cardiovascular Research), partner site Berlin, Germany
Correspondence to Dr Christiane Ott, Department of Molecular Toxicology, German Institute of Human Nutrition Potsdam-Rehbruecke, Arthur-Scheunert-Allee 114-116, D-14558 Nuthetal, Germany. Tel: +49 0 33200/88 2352; e-mail: Christiane.Ott@dife.de