Effects of UVB-induced oxidative stress on protein expression and specific protein oxidation in normal human epithelial keratinocytes: a proteomic approach

Abstract

BackgroundThe UVB component of solar ultraviolet irradiation is one of the major risk factors for the development of skin cancer in humans. UVB exposure elicits an increased generation of reactive oxygen species (ROS), which are responsible for oxidative damage to proteins, DNA, RNA and lipids. In order to examine the biological impact of UVB irradiation on skin cells, we used a parallel proteomics approach to analyze the protein expression profile and to identify oxidatively modified proteins in normal human epithelial keratinocytes.ResultsThe expression levels of fifteen proteins - involved in maintaining the cytoskeleton integrity, removal of damaged proteins and heat shock response - were differentially regulated in UVB-exposed cells, indicating that an appropriate response is developed in order to counteract/neutralize the toxic effects of UVB-raised ROS. On the other side, the redox proteomics approach revealed that seven proteins - involved in cellular adhesion, cell-cell interaction and protein folding - were selectively oxidized.ConclusionsDespite a wide and well orchestrated cellular response, a relevant oxidation of specific proteins concomitantly occurs in UVB-irradiated human epithelial Keratinocytes. These modified (i.e. likely dysfunctional) proteins might result in cell homeostasis impairment and therefore eventually promote cellular degeneration, senescence or carcinogenesis.

Kindlin-1 and -2 Have Overlapping Functions in Epithelial Cells

“…Gene regulation by UV irradiation is well studied in human skin and keratinocytes. A ninefold increase of ␣ 3 integrin and a 20-fold decrease of actin protein levels by UV-B 25 have been reported. Interestingly, in sun-exposed skin, expression of ␤ 1 integrin protein by epidermal basal cells was reduced, paralleling a down-regulation of ␤ 1 integrin mRNA.…”

Heat stress: A risk factor for skin carcinogenesis

“…ROS can covalently bind or directly oxidise proteins and can cause reversible or irreversible modifications including protein-protein cross linking, carbonylation, formation of adducts with lipid peroxidation products, and nitration (Perluigi et al, 2010;Vidal et al, 2014). These modifications often result in changes in stability, as well as functional and structural changes in proteins, which can lead to loss of protein function, protein aggregation and degradation, in turn causing DNA missense mutations.…”

Involvement of P2Y receptors in the protective effect of ATP towards the cell damage in HaCaT cells exposed to H2O2

“…There is growing evidence that plasma membrane-bound NADPH oxidase is a major source of ROS production induced by UV radiation in keratinocytes (Beak et al, 2004;Park et al, 2006) and that ROS generation requires elevation of intracellular Ca 2+ level in keratinocytes (Goldman et al, 1997;Masaki et al, 2009). ROS are highly reactive and are capable of causing oxidative DNA damage (Ehlers et al, 1999), altering membrane potential (Ehlers et al, 1999), peroxidizing proteins (Perluigi et al, 2010) and lipids (Punnonen et al, 1991), and inducing apoptosis (Clayton et al, 1974). Production of ROS contributes to several patho-physiological processes, such as cancer (Lopez-Torres et al, 1994), aging (Wallace et al, 1998), neurodegenerative diseases (Albers and Beal, 2000) and inflammatory disorders (Trenam et al, 1991).…”