C16ORF70/MYTHO promotes healthy aging in C.elegans and prevents cellular senescence in mammals
Anais Franco-Romero, … , Eva Trevisson, Marco Sandri
Anais Franco-Romero, … , Eva Trevisson, Marco Sandri
Published June 13, 2024
Citation Information: J Clin Invest. 2024;134(15):e165814. https://doi.org/10.1172/JCI165814.
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C16ORF70/MYTHO promotes healthy aging in C.elegans and prevents cellular senescence in mammals

Abstract

The identification of genes that confer either extension of life span or accelerate age-related decline was a step forward in understanding the mechanisms of aging and revealed that it is partially controlled by genetics and transcriptional programs. Here, we discovered that the human DNA sequence C16ORF70 encodes a protein, named MYTHO (macroautophagy and youth optimizer), which controls life span and health span. MYTHO protein is conserved from Caenorhabditis elegans to humans and its mRNA was upregulated in aged mice and elderly people. Deletion of the orthologous myt-1 gene in C. elegans dramatically shortened life span and decreased animal survival upon exposure to oxidative stress. Mechanistically, MYTHO is required for autophagy likely because it acts as a scaffold that binds WIPI2 and BCAS3 to recruit and assemble the conjugation system at the phagophore, the nascent autophagosome. We conclude that MYTHO is a transcriptionally regulated initiator of autophagy that is central in promoting stress resistance and healthy aging.

Authors

Anais Franco-Romero, Valeria Morbidoni, Giulia Milan, Roberta Sartori, Jesper Wulff, Vanina Romanello, Andrea Armani, Leonardo Salviati, Maria Conte, Stefano Salvioli, Claudio Franceschi, Viviana Buonomo, Casey O. Swoboda, Paolo Grumati, Luca Pannone, Simone Martinelli, Harold B.J. Jefferies, Ivan Dikic, Jennifer van der Laan, Filipe Cabreiro, Douglas P. Millay, Sharon A. Tooze, Eva Trevisson, Marco Sandri

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Figure 5

Depletion of Mytho reduces autophagic flux in vitro and in vivo.

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Depletion of Mytho reduces autophagic flux in vitro and in vivo. (A) Lef...
(A) Left: Representative images of HEK293 cells transfected with MYTHO-GFP. Right: Representative image of endogenous MYTHO. Scale bars: 10 μm. (B) Left: FDB muscles transfected with MYTHO-GFP. Right: Endogenous Mytho in FDB fibers. Scale bars: 10 μm. (C) Endogenous HA-tagged Mytho coimmunoprecipitates with LC3B. The asterisk (*) indicates a nonspecific band. (D) LC3 lipidation was analyzed by immunoblot in WT and Mytho-KO C2C12 cells treated or not with chloroquine. LC3-II band was normalized to GAPDH (n = 8) (2-tailed Student’s t test). (E) Left: Representative fluorescence images of WT and Mytho-KO C2C12 cells transfected with Cherry-LC3B and treated with chloroquine or vehicle. Scale bars: 10 μm. Right: Quantification of LC3 puncta/area of the cell in each condition is shown (n > 15 cells/condition) (1-way ANOVA with Tukey’s multiple-comparison test). (F) Top: Representative fluorescence images of GFP:LGG-1 puncta in the posterior bulb of the pharynx of N2 (WT) and myt-1(pan8) I worms. Scale bar: 25 μm. Bottom: Autophagosomal pool quantification in WT (n = 26) and myt-1(pan8) I (n = 20) worms (N = 3) (2-tailed Student’s t test). (G and H) Top: Representative fluorescence images of mCherry:LGG-1 puncta in the posterior bulb of the pharynx (G) and in body wall muscle (H) of N2 (WT) and myt-1(pan8) I worms. Scale bars: 25 μm (G) and 50 μm (H). Bottom: Relative quantification of mCherry:LGG-1 puncta in basal condition (Fed) and after 24-hour starvation (Starved) in M9 buffer. WT Fed (n = 14), myt-1(pan8) I Fed (n = 22), WT STV 24 h (n = 17), myt-1(pan8) I STV 24 h (n = 27); N = 2 (2-tailed Student’s t test). (I) Top: Representative fluorescence images of single fibers from FDB muscle transfected with YFP-LC3/3xFlagMYTHO or YFP-LC3/Flag–empty vector in basal condition. Scale bars: 20 μm. Bottom: Quantification of LC3 puncta in more than 12 fibers (2-tailed Student’s t test). All bars indicate SEM. *P < 0.05; **P < 0.01; ***P < 0.001; ****P < 0.0001. N = number of independent experiments; n = number of cells/samples.