Protective effect of skin-derived precursors on photoaging in nude mice

Facilitation of mouse skin-derived precursor growth and yield by optimizing plating density

Multiple methodologies have been reported to facilitate skin-derived precursor (SKP) growth, but the impact of plating density on SKP growth has not been studied. To determine the optimal plating density, we used six plating densities and two types of flasks for mouse SKP (mSKP) culture. On the 14th day, the number, diameter, and viability of mSKP spheres were compared by morphological assessment and cell counting kit 8, and we found the optimal plating density was 2.5 × 10⁵–5 × 10⁵ cells/mL. In addition, we investigated the correlation between the SKP spheres and the adherent cell colonies in the serum-free culture system. We treated the adherent cell colonies with two culture conditions and characterized the cells generated from two conditions by immunocytochemistry and induced differentiation, respectively. The results elucidated that the adherent cell colonies differentiated into either mSKPs or dermal mesenchymal stem cells under appropriate culture conditions. In conclusion, mSKP spheres differentiated from the adherent cell colonies. The optimal plating density significantly promoted and advanced the proliferation of adherent cell colonies, which optimized mSKP growth and yield. The adherent cell colonies possessed the capacity of differentiating into different types of cells under appropriate culture conditions.

Therapeutic Effects of Dipterocarpus tuberculatus with High Antioxidative Activity Against UV-Induced Photoaging of NHDF Cells and Nude Mice

To investigate the therapeutic effects of methanol extracts of Dipterocarpus tuberculatus Roxb. (MED) against UV-induced photoaging, we assessed for alterations in the antioxidant activity, anti-apoptotic effects, ECM modulation, skin appearances, and anti-inflammatory response in normal human dermal fibroblast (NHDF) cells and nude mice orally treated with MED. High levels of tannin content and high free radical scavenging activity to DPPH were determined in MED, while seven active components, namely, gallic acid, bergenin, ellagic acid, ε-viniferin, asiatic acid, oleanolic acid, and 2α-hydroxyursolic acid, were identified using LC–MS analyses. UV-induced alterations in the NO concentration, SOD activity, and Nrf2 expression were remarkably recovered in MED-treated NHDF cells. Moreover, the decreased number of apoptotic cells and G2/M phase arrest were observed in the UV + MED-treated groups. Similar recoveries were detected for β-galactosidase, MMP-2/9 expression, and intracellular elastase activity. Furthermore, MED treatment induced suppression of the COX-2-induced iNOS mediated pathway, expression of inflammatory cytokines, and inflammasome activation in UV-radiated NHDF cells. The anti-photoaging effects observed in NHDF cells were subsequently evaluated and validated in UV + MED-treated nude mice through skin phenotypes and histopathological structure analyses. Taken together, these results indicate that MED exerts therapeutic effects against UV-induced photoaging and has the potential for future development as a treatment for photoaging.

Mouse skin-derived precursors alleviates ultraviolet B irradiation damage via early activation of TGF-β/Smad pathway by thrombospondin1

Our previous research implied mouse skin-derived precursors (mSKPs) possessed the capacity of anti-ultraviolet B (UVB) irradiation damage, and the mechanisms might be associated with transforming growth factor-β (TGF-β) signaling pathway activation. In this study, we investigated and compared the response to UVB irradiation between mSKPs and dermal mesenchymal stem cells (dMSCs), and explored the underlying mechanisms. Irradiation damage such as decreased cell viability, cell senescence, and cell death was observed in both mSKPs and dMSCs at 24 h after UVB exposure. In mSKPs, change in cell morphology, viability, cell senescence and death at the following time points implied the recovery of UVB irradiation damage. Additionally, thrombospondin1 (TSP1) and TGF-β1 increased significantly in mSKPs' supernatant after UVB irradiation. The gene expression of TSP1, TGF-β1, metalloproteinase 1 (MMP1), and Collagen I elevated shortly after the UVB exposure. The protein expression of TSP1, TGF-β1, MMP1, Collagen I, smad2/3, and p-smad2/3 at multiple time points after the UVB exposure was consistent with the gene expression results. In dMSCs, no obvious recovery was noticed. Together, these results revealed that in mSKPs, one of the mechanisms to attenuate the UVB irradiation damage might be the early activation of TGF-β/Smad pathway by TSP1. Given that mSKPs could differentiate into fibroblast-like SKP-derived fibroblasts (SFBs) in vivo or with the presence of serum, mSKPs might serve as a therapeutic potential for fibroblasts supplement and UVB irradiation damage treatment.Abbreviations: SKPs: skin-derived precursors; mSKPs: mouse SKPs; UVB: ultraviolet B; TGF-β/Smad: transforming growth factor-β/Smad; TSP1: thrombospondin 1; MMP 13: metalloproteinases 13; TβRII: TGF-β receptor II; SFBs: SKP-derived fibroblasts; KEGG: Kyoto encyclopedia of genes and genomes; DEGs: differentially expressed genes; dMSCs: dermal mesenchymal stem cells; LM: light microscope; CCK-8: cell counting kit 8; ELISA: Enzyme-linked immuno sorbent assay; qRT-PCR: quantitative real-time polymerase chain reaction; TSPs: thrombospondins; ECM: extracellular matrix; R-smads: receptor-regulated smads.

Asiatic Acid Glucosamine Salt Alleviates Ultraviolet B-induced Photoaging of Human Dermal Fibroblasts and Nude Mouse Skin

Herbal extracts including asiatic acid (AA) have become popular candidates of anti-photoaging agents due to their anti-inflammatory and antioxidant properties and minimal side effect. Nevertheless, low bioavailability due to poor solubility limits their practical application. In this study, a highly bioavailable form of AA called AAGS (compounded by asiatic acid and glucosamine) was investigated for its anti-photoaging effect using both in vitro and in vivo models along with UVB irradiation. The results showed that AAGS alleviated UVB-induced cell proliferation inhibition by reducing G2 phase arrest and cell apoptosis rate as well as the gene expressions of P53, BAX, CASPASE 3 and CASPASE 9, but enhancing BCL-2 expression. It also reduced the production of reactive oxygen species along with increased gene expression of GPX-1 and downregulated the gene expression of IL-1β, IL-6, IL-8, IL-17 and TNF-α compared to nontreated cells. In vivo results demonstrated the antiphotodamaging effects by restoring skin thickness, collagen content and reducing MMPs expression, which are also supported by reduced MMPs gene expression and enhanced collagen I and TGF-β1 gene expression in vitro. Thus, AAGS may become a potential anti-photoaging agent for topical use due to its capability of self-assembling into a water gel.