NARILIS PhD student, Marie Toutfaire, among the Poster Prize Winners at the ESDR 2015!

Marie Toutfaire is a PhD student at the Laboratory of Cellular Biology of UNamur (URBC) who conducts research on skin aging under the mentorship of Florence Chainiaux. She studies the impact of environmental stress and more precisely of UVB on skin cells.

Simplified in vitro models, based on stress-induced premature senescence of human skin fibroblasts, have been developed at the URBC lab. The goal of Marie Toutfaire’s work is to unravel the signaling pathways leading to cellular senescence in order to better understand skin photo-aging.

In September 2015, Marie Toutfaire participated to the 45^th annual meeting of the European Society for Dermatological Research (ESDR) in Rotterdam, which is a renowned international meeting covering the latest developments in cutaneous biology, clinical and experimental dermatology.

During this conference, Marie Toutfaire presented a poster entitled "Signal transduction in UVB- or TGF-beta1-induced premature senescence of human dermal fibroblasts" (see abstract below). Her poster was selected for a guided “Poster Walk”, on the theme of Photobiology and accompanied by Thierry Passeron, dermatologist at the CHU of Nice and Professor at the University of Nice-Sophia Antipolis. And most importantly, Marie Toutfaire was awarded a poster prize at this 2015 edition of the ESDR meeting!

Picture of ESDR 2015 Poster Prize Winners: Marie Toutfaire (second from the left)

ABSTRACT

Signal transduction in UVB- or TGF-beta1-induced premature senescence of human dermal fibroblasts

M Toutfaire, E Descamps, O Toussaint and F Debacq-Chainiaux Biology (URBC), UNamur, Namur, Belgium

In vitro, most of proliferative cell types are characterised by a progressive loss of cell divisions leading to irreversible growth arrest. This mechanism refers to cellular ageing named replicative senescence. Stresses can also trigger the premature appearance of a senescent-like phenotype coined Stress Induced Premature Senescence (SIPS). SIPS displays several features of replicative senescence but the signaling pathways implicated in the appearance of the biomarkers of senescence remain unclear. We developed models of SIPS induced by UVB exposures or TGF-beta1 stimulation in human dermal fibroblasts. Human dermal fibroblasts were exposed to UVB radiation twice a day for five days or stimulated with TGF-beta1 for three days. We investigated in these models the signaling pathways implicated in the appearance of biomarkers of senescence such as senescence associated β-galactosidase (SA-ßgal) activity and Senescent Associated Secretory Phenotype (SASP), among which expression of inflammatory cytokines, metalloproteinases and growth factors. We investigated the TGF-beta signaling pathway and focused especially on Smad-dependent and Smad-independent pathways. We also analysed ERK and p38 MAPK signaling pathways. Our results suggest that Smad-dependent and Smad-independent pathways are partially modified during UVB- and TGF-beta1-induced premature senescence. These pathways could have a key role in the appearance of SIPS biomarkers.