Evandro F, Fang, Yujun, Hou, Sofie, Lautrup, Martin Borch, Jensen, Beimeng, Yang, Tanima, SenGupta, Domenica, Caponio, Rojyar, Khezri, Tyler G, Demarest, Yahyah, Aman, David, Figueroa, Marya, Morevati, Ho-Joon, Lee, Hisaya, Kato, Henok, Kassahun, Jong-Hyuk, Lee, Deborah, Filippelli, Mustafa Nazir, Okur, Aswin, Mangerich, Deborah L, Croteau, Yoshiro, Maezawa, Costas A, Lyssiotis, Jun, Tao, Koutaro, Yokote, Tor Erik, Rusten, Mark P, Mattson, Heinrich, Jasper, Hilde, Nilsen, and Vilhelm A, Bohr
Metabolic dysfunction is a primary feature of Werner syndrome (WS), a human premature aging disease caused by mutations in the gene encoding the Werner (WRN) DNA helicase. WS patients exhibit severe metabolic phenotypes, but the underlying mechanisms are not understood, and whether the metabolic deficit can be targeted for therapeutic intervention has not been determined. Here we report impaired mitophagy and depletion of NAD+, a fundamental ubiquitous molecule, in WS patient samples and WS invertebrate models. WRN regulates transcription of a key NAD+ biosynthetic enzyme nicotinamide nucleotide adenylyltransferase 1 (NMNAT1). NAD+ repletion restores NAD+ metabolic profiles and improves mitochondrial quality through DCT-1 and ULK-1-dependent mitophagy. At the organismal level, NAD+ repletion remarkably extends lifespan and delays accelerated aging, including stem cell dysfunction, in Caenorhabditis elegans and Drosophila melanogaster models of WS. Our findings suggest that accelerated aging in WS is mediated by impaired mitochondrial function and mitophagy, and that bolstering cellular NAD+ levels counteracts WS phenotypes., The molecular mechanisms of mitochondrial dysfunction in the premature ageing Werner syndrome were elusive. Here the authors show that NAD+ depletion-induced impaired mitophagy contributes to this phenomenon, shedding light on potential therapeutics.