Autophagy
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Autophagy, a highly conserved cellular mechanism wherein various cellular components are broken down and recycled through lysosomes, has been implicated in the development of heart failure. However, tools to measure autophagic flux in vivo have been limited. Here, we tested whether monodansylcadaverine (MDC) and the lysosomotropic drug chloroquine could be used to measure autophagic flux in both in vitro and in vivo model systems. ⋯ Using transgenic mice expressing 3 mCherry-LC3 exposed to rapamycin for 4 hr, we observed an increase in mCherry-LC3-labeled autophagosomes in myocardium, which was further increased by concurrent administration of chloroquine, thus allowing determination of flux as a more precise measure of autophagic activity in vivo. MDC injected 1 hr before sacrifice colocalized with mCherry-LC3 puncta, validating its use as a marker of autophagosomes. This study describes a method to measure autophagic flux in vivo even in non-transgenic animals, using MDC and chloroquine.