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In 2023, UNamur opened a fourth CaNDLE call funded through the joint support of the Fonds Jérôme pour le développement durable and the Assemblée des Cercles of UNamur students. Discover one of the 7 selected projects.

Summary: Impact of the UPR pathway on the establishment of the UVB-induced senescent phenotype Skin aging, influenced by a combination of intrinsic and extrinsic factors, leads to damage capable of altering skin functions. Among extrinsic factors, ultraviolet (UV) radiation is responsible for skin photoaging. In particular, these elements lead to an accumulation of senescent cells capable of contributing to the development of age-related pathologies such as skin cancers. Indeed, senescence is accompanied by profound morphological and molecular changes within the cell. This includes a modification of its secretome, which becomes enriched with pro-inflammatory cytokines, growth factors and extracellular matrix remodeling enzymes, altering the characteristics of tissues as they age. Nevertheless, the precise mechanisms leading to the senescent phenotype induced by UVB remain largely unknown. In this context, the main objective of this work was to identify molecular mechanisms underlying the establishment of UVB-induced senescence in normal human dermal fibroblasts (NHDFs), mechanisms that could contribute to skin aging. In vitro, we confirmed that repeated UVB exposures induce premature senescence in NHDFs and that this state is associated with activation of the three branches of the UPR (Unfolded Protein Response) pathway responsible for maintaining homeostasis of the endoplasmic reticulum (ER), the primary secretory compartment. These observations were supported by transcriptomic analysis, revealing regulatory elements linked to major senescence pathways and ER functions in UVB-exposed NHDFs. Subsequently, we showed that the ATF6α branch plays a central role in the occurrence of biomarkers of the UVB-induced senescent phenotype. Indeed, ATF6α invalidation not only protects against UVB-induced morphological changes, but reduces the percentage of SA-βgalactosidase (SA-βgal)-positive cells, prevents persistent DNA damage, and alters the expression of major factors of the senescence-associated secretory phenotype (SASP). As SASP exerts, among other things, a pro-tumoral action, we sought to assess whether the conditioned medium (CM) of UVB-exposed fibroblasts invalidated for ATF6α could impact the migration and invasion potential of melanoma-derived cells. However, we did not observe any ATF6α-dependent pro-migratory or pro-invasive effects.To highlight a potential role for ATF6α in another biological process, we exploited our transcriptomic and secretomic analyses and identified a possible effect of ATF6α on the paracrine control of the skin environment. To explore this, we focused on SASP factors (cytokines and metalloproteases) regulated by ATF6α and whose impact on the tissue environment was known. Next, we treated a reconstructed human epidermis (RHE) model with MC derived from NHDFs exposed to UVB or not, and invalidated or not for ATF6α. Surprisingly, we observed that MC from UVB-exposed NHDFs increased RHE thickness and basal keratinocyte proliferation, via an ATF6α-dependent mechanism. Finally, we identified IL8 as a major paracrine factor involved in this process, since IL-8 blockade by neutralizing antibodies prevents excessive keratinocyte proliferation. In conclusion, we report the role of ATF6α in UVB-induced senescence as well as its impact on the preservation of skin homeostasis under stress conditions notably through the regulation of the expression of SASP components. This suggests that ATF6α and its effectors could be promising targets controlling the effects of skin aging.Abstract: Impact of the UPR pathway on the establishment of the senescent phenotype induced by UVBSkin aging, influenced by a combination of intrinsic and extrinsic factors, can result in damage that has the potential to alter skin functions. Among extrinsic factors, ultraviolet (UV) radiation is responsible for skin photoaging. These factors notably contribute to the accumulation of senescent cells which in turn can contribute to the development of age-related pathologies, including skin cancers. Indeed, senescence is characterized by profound morphological and molecular changes within the cell. This includes a modification of its secretome, which becomes enriched in pro-inflammatory cytokines, growth factors, and matrix-remodeling enzymes, altering tissue characteristics during aging. However, the exact mechanisms driving the senescent phenotype induced by UVB remain largely unknown. In this context, the main objective of this work was to identify the underlying molecular mechanisms responsible for the establishment of UVB-induced senescence in normal human dermal fibroblasts (NHDFs), mechanisms that may play a role in skin aging. In vitro, we confirmed that repeated exposures to UVB induce premature senescence of NHDFs and that this state is associated with the activation of the three branches of the Unfolded Protein Response (UPR), which are responsible for maintaining endoplasmic reticulum (ER) homeostasis, the primary cellular secretion compartment. These observations were supported by transcriptomic analysis, revealing regulatory elements related to major senescence pathways and ER functions in UVB-exposed NHDFs. Subsequently, we demonstrated that the ATF6α branch plays a central role in the development of the UVB-induced senescent phenotype. Indeed, the silencing of ATF6α not only protects against morphological changes induced by UVB, but also reduces the percentage of senescence-associated β-galactosidase (SA-βgal) positive cells, prevents the persistence of DNA damage, and alters the expression of major factors associated with the senescence-associated secretory phenotype (SASP).The SASP, exerting a pro-tumoral action, led us to assess whether the conditioned medium (CM) from UVB-exposed fibroblasts invalidated for ATF6α could impact the migration and invasion potential of melanoma cells. However, we did not observe any ATF6α-dependent pro-migratory or pro-invasive effects. To highlight a potential role of ATF6α in another biological process, we further analyzed our transcriptomic and secretomic analyses and identified a possible effect of ATF6α on the paracrine control of the skin environment. To explore this, we focused on SASP factors (cytokines and metalloproteinases) regulated by ATF6α and whose impact on tissue environment was known. Subsequently, we treated a reconstructed human epidermis (RHE) model with CM from NHDFs exposed or not to UVB and invalidated or not for ATF6α. Surprisingly, we observed that the CM from UVB-exposed NHDFs increased the thickness of the RHE as well as the proliferation of basal keratinocytes, via an ATF6α-dependent mechanism. Finally, we identified IL8 as a major paracrine factor involved in this process, as blocking IL-8 with neutralizing antibodies prevented excessive proliferation of keratinocytes. In conclusion, we report the role of ATF6α in UVB-induced senescence and its impact on the preservation of skin homeostasis under stress conditions, particularly through the regulation of the expression of SASP components. This suggests that ATF6α and its effectors could be promising targets for controlling the effects of skin aging. Jury Prof. Yves POUMAY (Department of Medicine, UNamur), chairmanProf. Florence CHAINIAUX (Department of Biology, UNamur), promoter and secretaryProf. Olivier PLUQUET (Canther, University of Lille), co-promoterProf. Isabelle PETROPULOS (Adaptation Biologique et Vieillissement, Sorbonne Université)Prof. Jérôme LAMARTINE (Laboratoire de Biologie Tissulaire et d'Ingénierie thérapeutique, Université Claude Bernard Lyon 1)Prof. Fabienne FOUFELLE (Maladies métaboliques, diabète et comorbidités, Sorbonne Université)

What environmental impact can a contraceptive molecule have? Recent work by Professor Patrick Kestemont, Director of UNamur's Environmental and Evolutionary Biology Research Unit (URBE) and his team answers this question, and has just been published in the journal Environment International. The article's lead author is Sébastien Baekelandt, postdoctoral researcher at URBE.

The F.R.S.-FNRS published on June 25, 2024, the list of winners of the various doctoral and postdoctoral mandates. Among them, 16 researchers from the University of Namur have obtained funding.

In 2023, UNamur opened a fourth CaNDLE call funded through the joint support of the Fonds Jérôme pour le développement durable and the Assemblée des Cercles of UNamur students. Discover one of the 7 selected projects.

In 2025-2026, UNamur's Faculty of Sciences has the honor and privilege of hosting Professor Sander Jacobs on the occasion of a Francqui Chair awarded to him by the Francqui Foundation: "Repairing our relationship with Nature to transform our societies". Sander Jacobs is Senior Researcher at INBO (Institute for Nature and Forest), Nature & Society research group, Coordinator of the Urban Nature research program and Visiting Professor at Ghent University.

Located in the Indian Ocean, Madagascar is an island with a rich natural heritage and multiple cultural influences. For over 15 years, researchers from the University of Namur have been working with a number of Madagascan universities and institutes on a variety of themes, including environmental preservation, water management and institutional capacity building. Focus on some of these projects.

In late November, the Mont-Saint-Guibert-based company Cellistic® donated equipment it no longer used to UNamur. By enabling the university to give this equipment a second life, Cellistic is making an important gesture in support of the development of university research.

A program for every discipline During late August and early September, UNamur offers rheto students preparatory courses tailored to their future training.These revision sessions are specially designed to support students in their transition to university. By reinforcing their foundations in the key subjects of their future discipline, they enable them to approach their first year with confidence. These preparatory courses are also an excellent opportunity to discover the campus, meet future classmates and familiarize themselves with the learning methods specific to higher education. Discover the preparatory courses Preparation for the medical entrance exam For students wishing to begin studying medicine, two sessions are also organized according to a specific timetable to prepare for the entrance exam. Discover the preparatory courses for the entrance exam to medicine

Since September 2023, Marc Hennequart, Professor of Biochemistry and Cell Biology at UNamur, has been conducting groundbreaking research into pancreatic cancer. His team, based at the Faculty of Medicine and the Institut Narilis, studies the early stages of oncogenesis (the process of transforming a normal cell into a cancerous one) to better understand the metabolic changes behind this particularly aggressive cancer.

The Lab of Environmental Change and Community Ecology (LEEE) is directed by Professor Frédéric De Laender. It is one of 4 laboratories belonging to the Environmental and Evolutionary Biology Research Unit (URBE) within the Biology Department. The LEEE is also a member of the Institute of Life, Earth and Environment (ILEE).

Space has become a major economic and strategic issue. As a member of the European UNIVERSEH Alliance, UNamur explores this space theme in its various departments, from physics to geology, via mathematics, computer science or philosophy. Without forgetting to address the general public, who still dream of the stars...