Nrf2 Overexpression for the Protective Effect of Skin-Derived Precursors against UV-Induced Damage: Evidence from a Three-Dimensional Skin Model

Abstract

Background Skin photodamage is associated with ultraviolet- (UV-) induced reactive oxygen species (ROS) overproduction and nuclear factor erythroid 2-related factor 2 (Nrf2) inactivation. In our previous study, skin-derived precursors (SKPs) were shown to ameliorate a UV-induced damage in mice, probably through Nrf2 activation and ROS scavenging. Objective To clarify the mechanism underlying the photoprotective effect of SKPs against UV-induced damage in a three-dimensional (3D) skin model. Methods The Nrf2 gene in SKPs was modified using lentiviral infection, and 3D skin models were reconstructed with keratinocytes and fibroblasts on the basis of type I collagen. Subsequently, these models were divided into the following six groups: normal, model, overexpressed, control, silenced, and negative control groups. Prior to irradiation, respective SKPs were injected into the last four groups. Next, all groups except the normal group were exposed to UVA+UVB. Lastly, the pathological and molecular-biological techniques were employed to determine the parameters. Additionally, LY294002, a PI3K inhibitor, was used to investigate the roles of PI3K/Akt and Nrf2/hemeoxygenase-1 (HO-1) in SKP photoprotection. Results Normal 3D skin models appeared as milky-white analogs with a clear, well-arranged histological structure. After the skin was exposed to irradiation, it exhibited cell swelling and a disorganized structure and developed nuclear condensation with numerous apoptotic cells. The expressions of cellular protective genes and Nrf2/HO-1/PI3K/Akt proteins remarkably decreased, which were accompanied by increased oxidative stress and decreased antioxidants (P < 0.05). However, these phenomena were reversed by nrf2-overexpressing SKPs. The 3D skin in the overexpressed group showed mild swelling, neatly arranged cells, and few apoptotic cells. Cellular protective genes and Nrf2/HO-1/PI3K/Akt proteins were highly expressed, and the oxidative biomarkers were remarkably ameliorated (P < 0.05). Nevertheless, the expression of these proteins decreased after LY294002 pretreatment regardless of SKP treatment or not. Meanwhile, there were increases in both UV-induced apoptotic cells and ROS level accompanied with SOD and GPX decrease in the presence of LY294002. Conclusions Evidence from the 3D skin model demonstrates that the protection of SKPs against UV-mediated damage is primarily via the PI3K/Akt-mediated activation of the Nrf2/HO-1 pathway, indicating that SKPs may be a promising candidate for the treatment of photodermatoses.

Effects of Rutin on Wound Healing in Hyperglycemic Rats

“…Cells and tissues in a hyperglycemic environment induce the generation of ROS, promote inflammatory response, and delay wound healing [ 30 ]. NRF2 prevents oxidative stress and regulates the production of related antioxidant enzymes, such as SOD1, GPx, heme oxygenase 1 (HO-1), and catalase [ 31 , 32 ]. The results of this study also confirmed that rutin increases the production of antioxidant enzymes SOD1 and GPx by upregulating the expression of NRF2 ( Figure 6 A).…”

Combined Effects of Carotenoids and Polyphenols in Balancing the Response of Skin Cells to UV Irradiation

“…Contrary to the inhibition of the NFκB transcription system, the phytonutrient combinations resulted in a synergistic activation of the ARE/Nrf2 transcription system. UV-induced ROS generation is a major mechanism through which UV causes detrimental effects on skin [ 32 ] and, thus, activation of ARE/Nrf2 is one of the basic mechanisms to balance UV-induced skin damage, as was shown in a 3D skin model injected with Nrf2 over-expressing skin-derived precursor cells [ 33 ]. The inhibition of NFκB and activation of ARE/Nrf2 by various carotenoids and polyphenols was previously shown in several publications [ 22 , 26 , 34 , 35 ].…”

Laminarin Attenuates Ultraviolet-Induced Skin Damage by Reducing Superoxide Anion Levels and Increasing Endogenous Antioxidants in the Dorsal Skin of Mice

“…It has been well known that endogenous antioxidant enzymes, such as SODs, GPx, and CAT, scavenge ROS [ 31 ]. Recently, Xian et al (2019) have reported that UV irradiation significantly elevates the level of ROS, however, nuclear factor erythroid 2-related factor 2 (Nrf2) overexpression in the skin-derived precursors (SKP) significantly ameliorates UV-induced damage in mice via the remarkable elevation of SOD, CAT, GPx, and reduced glutathione mRNA and protein levels, through Nrf2/HO-1 and PI3K/Akt pathways in a three-dimensional skin model [ 32 ]. In addition, it has been reported that the anti-photoaging effects of natural antioxidants, such as sinapic acid [ 33 ] and juglanin [ 34 ], are mediated by decrease of ROS generation and increases of SOD1, SOD2, CAT, GPx, and Nrf2 gene expression levels in UVB irradiation-damaged HaCaT keratinocytes.…”