Cellular rejuvenation protects neurons from inflammation mediated cell death (ATAC-seq).

In multiple sclerosis (MS), invasion of the central nervous system by peripheral immune cells, activation of resident microglia and astrocytes, and demyelination occur as a cascade of events that trigger neuronal damage and death. The molecular signals in neurons that activate damage in response to the complex immune environment have not been fully characterized. Retinal ganglion cell neurons (RGCs) of the central nervous system (CNS) undergo axonal injury and cell death in MS and this is recapitulated in the experimental autoimmune encephalomyelitis (EAE) mouse model of MS. To profile the molecular landscape of pathologically inflamed neurons, we isolated RGCs from mice that were subjected to the EAE protocol and performed RNA-sequencing and ATAC-sequencing analysis. Pathway analysis of the RNA-sequencing data revealed that RGCs exhibited a molecular signature reminiscent of aged neurons with features of senescence. Pathway level analysis of single-nucleus RNA-sequencing analysis of human MS neurons also demonstrated a similar senescence-like phenotype. Immunofluorescence analyses confirmed alterations to various markers of senescence in RGCs in EAE mice, including alterations to the nuclear envelope, changes to chromatin marks, and accumulation of DNA damage. Transduction of RGCs with an Oct4-Sox2-Klf4 transgene to rejuvenate neurons to a younger epigenetic and transcriptomic state in the EAE model was sufficient to increase survival of RGCs. Together, this work reveals a novel senescent like phenotype in neurons in a model of pathological inflammation and in neurons from MS patients. Rejuvenation of the aged transcriptome improves visual acuity and neuronal survival in the EAE model supporting the notion that anti-aging therapies and/or senotherapeutic agents may directly target neurons for neuroprotection in autoimmune disorders.