CEFISES Seminar: Maël Lemoine, “Can the aging of an organism be reduced to the aging of its cells?”

Series: MolDevBio

Speaker: Maël Lemoine (Université de Bordeaux)

Title: “Can the aging of an organism be reduced to the aging of its cells?”

Abstract

Contemporary biogerontology is largely driven by “aging cell reductionism”: the hypothesis that intracellular degradations ultimately explain other aspects of the aging of organisms (typically, Lopez-Otin 2013). Indeed, “cell-autonomous” processes are not caused by extrinsic influence of the tissue (e.g., by concentration of byproducts of other cells, alteration of the extracellular matrix, etc.). The question is whether they really cause all aspects of aging. Experimental research programs generally presuppose it and investigate cell-autonomous processes or admit that non-cell-autonomous processes are derived from them. However, alternative theories could state that just like a population self-maintains by renewing degraded individuals, some tissues may self-maintain by renewing degraded cells. I want to develop 3 arguments to establish that some version of this population theory should be accepted by default for evolutionary reasons, instead of cell reductionism for mainly experimental reasons, and that the study of “cell-autonomous” processes of aging should be interpreted in the light of a cell-population theory. The first argument revolves around the origin of multicellular organisms in a perpetual population dynamic of colonies of unicellular organisms. The second argument revolves around whether a first layer of mechanisms of cell degradation that are known to exist in similar forms in all eukaryotes, unicellular and multicellular (Lemoine 2021), is likely to cause cumulative damage beyond the cell membrane. The third argument denies the plausibility that some mechanisms of unicellular aging have evolved de novo in the environment of a tissue.

Lemoine, M. (2021). The Evolution of the Hallmarks of Aging. Frontiers in Genetics, 12, 693071.

López-Otín, C., Blasco, M. A., Partridge, L., Serrano, M., & Kroemer, G. (2013). The Hallmarks of Aging. Cell, 153(6), 1194-1217.