Cell senescence has diverse, often opposing roles in organisms, and more surprises may lie ahead. Whereas its link to pathophysiological ageing has led to promising senotherapies, the protective role of senescence against cancer is tempered by its tumour-promoting properties. Nevertheless, senescence is essential in physiology, such as in mammalian development and in promoting cell proliferation and plasticity, which enhances tissue repair — functions that remain incompletely understood.

The importance of this study lies not only in demonstrating that cell senescence is necessary and sufficient for driving the reprogramming of somatic cells into pluripotent stem cells, but also in enabling regeneration in typically non-regenerative cells. A similar, though rudimentary, process occurs in mice, where SASPs promote cell reprogramming, including in refractory tissues such as skeletal muscle.