RESUMO
Ageing is a degenerative process that leads to tissue dysfunction and death. A proposed cause of ageing is the accumulation of epigenetic noise that disrupts gene expression patterns, leading to decreases in tissue function and regenerative capacity1-3. Changes to DNA methylation patterns over time form the basis of ageing clocks4, but whether older individuals retain the information needed to restore these patterns-and, if so, whether this could improve tissue function-is not known. Over time, the central nervous system (CNS) loses function and regenerative capacity5-7. Using the eye as a model CNS tissue, here we show that ectopic expression of Oct4 (also known as Pou5f1), Sox2 and Klf4 genes (OSK) in mouse retinal ganglion cells restores youthful DNA methylation patterns and transcriptomes, promotes axon regeneration after injury, and reverses vision loss in a mouse model of glaucoma and in aged mice. The beneficial effects of OSK-induced reprogramming in axon regeneration and vision require the DNA demethylases TET1 and TET2. These data indicate that mammalian tissues retain a record of youthful epigenetic information-encoded in part by DNA methylation-that can be accessed to improve tissue function and promote regeneration in vivo.
Assuntos
Envelhecimento/genética , Reprogramação Celular/genética , Metilação de DNA , Epigênese Genética , Olho , Regeneração Nervosa/genética , Visão Ocular/genética , Visão Ocular/fisiologia , Envelhecimento/fisiologia , Animais , Axônios/fisiologia , Linhagem Celular Tumoral , Sobrevivência Celular , Proteínas de Ligação a DNA/genética , Dependovirus/genética , Dioxigenases , Modelos Animais de Doenças , Olho/citologia , Olho/inervação , Olho/patologia , Feminino , Vetores Genéticos/genética , Glaucoma/genética , Glaucoma/patologia , Humanos , Fator 4 Semelhante a Kruppel , Fatores de Transcrição Kruppel-Like/genética , Camundongos , Camundongos Endogâmicos C57BL , Fator 3 de Transcrição de Octâmero/genética , Traumatismos do Nervo Óptico/genética , Proteínas Proto-Oncogênicas/genética , Células Ganglionares da Retina/citologia , Fatores de Transcrição SOXB1/genética , Transcriptoma/genéticaRESUMO
DNA repair is essential for life, yet its efficiency declines with age for reasons that are unclear. Numerous proteins possess Nudix homology domains (NHDs) that have no known function. We show that NHDs are NAD+ (oxidized form of nicotinamide adenine dinucleotide) binding domains that regulate protein-protein interactions. The binding of NAD+ to the NHD domain of DBC1 (deleted in breast cancer 1) prevents it from inhibiting PARP1 [poly(adenosine diphosphate-ribose) polymerase], a critical DNA repair protein. As mice age and NAD+ concentrations decline, DBC1 is increasingly bound to PARP1, causing DNA damage to accumulate, a process rapidly reversed by restoring the abundance of NAD+ Thus, NAD+ directly regulates protein-protein interactions, the modulation of which may protect against cancer, radiation, and aging.