A drug-induced accelerated senescence (DIAS) is a possibility to study aging in time lapse

Abstract

Currently, the oxidative stress (or free radical) theory of aging is the most popular explanation of how aging occurs at the molecular level. Accordingly, a stress-induced senescence-like phenotype of human dermal fibroblasts can be induced in vitro by the exposure of human diploid fibroblasts to subcytotoxic concentrations of hydrogen peroxide. However, several biomarkers of replicative senescence e.g. cell cycle arrest and enlarged morphology are abrogated 14 days after treatment, indicating that reactive oxygen species (ROS) rather acts as a trigger for short-term senescence (1-3 days) than being responsible for the maintenance of the senescence-like phenotype. Further, DNAdamaging factors are discussed resulting in a permanent senescent cell type. To induce long-term premature senescence and to understand the molecular alterations occurring during the aging process, we analyzed mitomycin C (MMC) as an alkylating DNA-damaging agent and ROS producer. Human dermal fibroblasts (HDF), used as model for skin aging, were exposed to noncytotoxic concentrations of MMC and analyzed for potential markers of cellular aging, for example enlarged morphology, activity of senescenceassociated-ß-galactosidase, cell cycle arrest, increased ROS production and MMP1-activity, which are welldocumented for HDF in replicative senescence. Our data show that mitomycin C treatment results in a drug-induced accelerated senescence (DIAS) with long-term expression of senescence markers, demonstrating that a combination of different susceptibility factors, here ROS and DNA alkylation, are necessary to induce a permanent senescent cell type.

A three‐dimensional skin equivalent reflecting some aspects of in vivo aged skin

“…To be sure that the MMC treatment of HDF in 3D skin equivalents induces similar effects as in monolayer cultures , resulting in a premature and stable senescence, fibroblasts were isolated out of the skin equivalents and analysed for ageing markers, which are well documented for replicative senescent fibroblasts (Fig. a–g).…”

“…By contrast, treatment with MMC resulted in an irregular, enlarged cell shape (Fig. 3a) which is typical for senescent fibroblasts (7,29).…”

“…3d), in contrast to isolated cells out of MMC-treated skin equivalents (DIAS), where only 5% of the cells were Ki67 positive. Next to Ki67, the activity of the tumor suppressor protein p53 is upregulated in senescent cells (7,32,33). A 3.7-fold increased activity of p53 was measured after MMC treatment (DIAS) in comparison with untreated isolated fibroblasts (mitotic) (Fig.…”

“…Our previous work showed that MMC is able to induce a premature accelerated and permanent senescent cell type (drug‐induced accelerated senescence, DIAS), which mimics the ageing process in time lapse . However, DIAS was studied in fibroblast monolayer cultures so far.…”

Senescent cell death as an aging resistance mechanism in naked mole-rat

“…To evaluate the response of NMR cells to other cellular senescence-inducing stimuli, we treated fibroblasts with a low concentration of mitomycin C (MMC), a DNA-damaging alkylating agent that induces premature senescence at low concentration 40 . 10 days after the MMC treatment, both mouse and NMR fibroblasts upregulated cellular senescence markers, however, only in NMR fibroblasts but not in mouse-fibroblasts, the activation of cell death was observed (Supplementary Supplementary Fig.…”