Long-term exposure to TNF-α leads human skin fibroblasts to a p38 MAPK- and ROS-mediated premature senescence
Tumor necrosis factor α (TNF-α) is an inflammatory mediator overexpressed in the skin as a response to ultraviolet radiation, as well as in chronic non-healing wounds. On the other hand, senescent fibroblasts have been shown to accumulate in the skin under these stressful conditions. Accordingly, here we assessed the putative implication of TNF-α in the induction of premature senescence of human adult dermal fibroblasts. We showed that TNF-α led to a rapid transient p38 MAPK activation, while elevation of reactive oxygen species (ROS) only occurred after a chronic exposure to TNF-α. Furthermore, in contrast to the majority of previous reports using various cell models and experimental settings, it was a long-term treatment with TNF-α that resulted in the premature senescence of human dermal fibroblasts, as shown by the reduced proliferative potential and the increased senescence associated β-galactosidase staining of the cells. TNF-α-senescent cells displayed a permanent phosphorylation of p38 MAPK and an inflammatory and catabolic phenotype. Increased ROS levels were also observed, possibly attributed to the weakened anti-oxidative response evidenced by the underexpression of the Nrf2-regulated genes encoding HO-1 and NQO1. These traits and the overall senescent phenotype were significantly reversed using the known anti-oxidant N-acetyl-l-cysteine or a specific p38 MAPK inhibitor, suggesting the participation of oxidative stress and of the p38 MAPK pathway in TNF-α-triggered premature senescence. Even more, the observed blockade of ROS accumulation in senescent skin fibroblasts by p38 MAPK inhibition indicates a possible link between these two separate events during the manifestation of TNF-α-induced senescence.
KeywordsDermal fibroblasts Inflammation Wound SA-β Gal p16INK4a Proliferation Nrf2 MMPs HO-1 NQO1
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Conflict of interest
The authors declare that they have no conflict of interest.
- Armatas AA, Pratsinis H, Mavrogonatou E, Angelopoulou MT, Kouroumalis A, Karamanos NK, Kletsas D (2014) The differential proliferative response of fetal and adult human skin fibroblasts to TGF-beta is retained when cultured in the presence of fibronectin or collagen. Biochim Biophys Acta 1840:2635–2642CrossRefGoogle Scholar
- Campisi J (1998) The role of cellular senescence in skin aging. J Investig Dermatol Symp Proc 3:1–5Google Scholar
- Dumont P, Balbeur L, Remacle J, Toussaint O (2000) Appearance of biomarkers of in vitro ageing after successive stimulation of WI-38 fibroblasts with IL-1alpha and TNF-alpha: senescence associated beta-galactosidase activity and morphotype transition. J Anat 197(4):529–537CrossRefPubMedCentralGoogle Scholar
- Kandhaya-Pillai R, Miro-Mur F, Alijotas-Reig J, Tchkonia T, Kirkland JL, Schwartz S (2017) TNFalpha-senescence initiates a STAT-dependent positive feedback loop, leading to a sustained interferon signature, DNA damage, and cytokine secretion. Aging (Albany NY) 9:2411–2435Google Scholar
- Lee JM, Johnson JA (2004) An important role of Nrf2-ARE pathway in the cellular defense mechanism. J Biochem Mol Biol 37:139–143Google Scholar
- Toussaint O et al (2001) Oxidative stress-induced cellular senescence. In: eLS. Wiley, ChichesterGoogle Scholar
- Zhang Y, Herbert BS, Rajashekhar G, Ingram DA, Yoder MC, Clauss M, Rehman J (2009) Premature senescence of highly proliferative endothelial progenitor cells is induced by tumor necrosis factor-alpha via the p38 mitogen-activated protein kinase pathway. FASEB J 23:1358–1365CrossRefPubMedCentralGoogle Scholar