Cellular Senescence in Glial Cells: Implications for Multiple Sclerosis

Aging is the most common risk factor for Multiple Sclerosis (MS) disease progression. Cellular senescence, the irreversible state of cell cycle arrest, is the main driver of aging and has been found to accumulate prematurely in neurodegenerative diseases, including Alzheimer's and Parkinson's disease. Cellular senescence in the central nervous system of MS patients has recently gained attention, with several studies providing evidence that demyelination induces cellular senescence, with common hallmarks of p16INK4A and p21 expression, oxidative stress, and senescence-associated secreted factors. Here we discuss the current evidence of cellular senescence in animal models of MS and different glial populations in the central nervous system, highlighting the major gaps in the field that still remain. As premature senescence in MS may exacerbate demyelination and inflammation, resulting in inhibition of myelin repair, it is critical to increase understanding of cellular senescence in vivo, the functional effects of senescence on glial cells, and the impact of removing senescent cells on remyelination and MS. This emerging field holds promise for opening new avenues of treatment for MS patients.