HEPES activates a MiT/TFE-dependent lysosomal-autophagic gene network in cultured cells: A call for caution.

HEPES activates a MiT/TFE-dependent lysosomal-autophagic gene network in cultured cells: A call for caution. Autophagy. 2018 Feb 17;:1-13 Authors: Tol MJ, van der Lienden MJC, Gabriel TL, Hagen JJ, Scheij S, Veenendaal T, Klumperman J, Donker-Koopman WE, Verhoeven AJ, Overkleeft H, Aerts JM, Argmann CA, van Eijk M Abstract In recent years, the lysosome has emerged as a highly dynamic, transcriptionally regulated organelle that is integral to nutrient-sensing and metabolic rewiring. This is coordinated by a lysosome-to-nucleus signaling nexus in which MTORC1 controls the subcellular distribution of the microphthalmia-transcription factor E (MiT/TFE) family of "master lysosomal regulators". Yet, despite the importance of the lysosome in cellular metabolism, the impact of traditional in vitro culture media on lysosomal dynamics and/or MiT/TFE localization has not been fully appreciated. Here, we identify HEPES, a chemical buffering agent that is broadly applied in cell culture, as a potent inducer of lysosome biogenesis. Supplementation of HEPES to cell growth media is sufficient to decouple the MiT/TFE family members-TFEB, TFE3 and MITF-from regulatory mechanisms that control their cytosolic retention. Increased MiT/TFE nuclear import in turn drives the expression of a global network of lysosomal-autophagic and innate host-immune response genes, altering lysosomal dynamics, proteolytic capacity, autophagic flux, and inflammatory signal...
Source: Autophagy - Category: Cytology Authors: Tags: Autophagy Source Type: research