Abstract
The effect of gold nanoparticles (GNPs) synthesized in marine algae has been described in the context of skin, where they have shown potential benefit. Ecklonia stolonifera (ES) is a brown algae that belongs to the Laminariaceae family, and is widely used as a component of food and medicine due to its biological activities. However, the role of GNPs underlying cellular senescence in the protection of Ecklonia stolonifera gold nanoparticles (ES-GNPs) against UVA irradiation is less well known. Here, we investigate the antisenescence effect of ES-GNPs and the underlying mechanism in UVA-irradiated human dermal fibroblasts (HDFs). The DPPH and ABTS radical scavenging activity of ES extracts was analyzed. These analyses showed that ES extract has potent antioxidant properties. The facile and optimum synthesis of ES-GNPs was established using UV-vis spectra. The surface morphology and crystallinity of ES-GNPs were demonstrated using high resolution transmission electron microscopy (HR-TEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FT-IR). ES-GNPs presented excellent photocatalytic activity, as shown by the photo-degradation of methylene blue and rhodamine B. A cellular senescence model was established by irradiating HDFs with UVA. UVA-irradiated HDFs exhibited increased expression of senescence-associated β-galactosidase (SA-β-galactosidase). However, pretreatment with ES-GNPs resulted in reduced SA-β-galactosidase activity in UVA-irradiated HDFs. Intracellular ROS levels and G1 arrest in UVA-irradiated HDFs were checked against the background of ES-GNP treatment to investigate the antisenescence effects of ES-GNPs. The results showed that ES-GNPs significantly inhibit UVA-induced ROS levels and G1 arrest. Importantly, ES-GNPs significantly downregulated the transcription and translation of MMP (matrix metalloproteinases)-1/-3, which regulate cellular senescence in UVA-irradiated HDFs. These findings indicate that our optimal ES-GNPs exerted an antisenescence effect on UVA-irradiated HDFs by inhibiting MMP-1/-3 expression. Collectively, we posit that ES-GNPs may potentially be used to treat photoaging of the skin.
Highlights
Skin photoaging happens as a result of exposure to ultraviolet (UV) light
When human dermal fibroblasts (HDFs) are exposed to UVA irradiation, there is an increase in the production of reactive oxygen species (ROS), which leads to apoptosis, upregulation of matrix metalloproteinases (MMPs) expression, and the induction of senescence
The Ecklonia stolonifera extract can serve as a metal nanoparticle reducing agent due to the presence of many phlorotannins, phenolic compounds, terpenoids, steroids, and vitamins that can be used during the reduction, capsulation, and stabilization of ES-gold nanoparticles (GNPs)
Summary
Skin photoaging happens as a result of exposure to ultraviolet (UV) light. Only 5% of solar radiation reaches the Earth’s surface, comprising wavelengths in the ranges of 315–400 nm (ultraviolet A (UVA)), 280–315 nm (UVB), 100-280 nm (UVC). Repeated exposure of human dermal fibroblasts (HDFs) to UVA irradiation has been established as a cellular senescence model to investigate certain characteristics of epidermal and dermal skin photoaging. When HDFs are exposed to UVA irradiation, there is an increase in the production of ROS, which leads to apoptosis, upregulation of matrix metalloproteinases (MMPs) expression, and the induction of senescence. UVA irradiation has been reported to directly or indirectly lead to the release of inflammatory mediators, as well as pro-inflammatory cytokines. All these UVA-induced factors are responsible for macro- and micro- structural deterioration of human skin [5,6,7]
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