Ultraviolet B Preconditioning Enhances the Hair Growth-Promoting Effects of Adipose-Derived Stem Cells Via Generation of Reactive Oxygen Species

Abstract

Hypoxia induces the survival and regenerative potential of adipose-derived stem cells (ASCs), but there are tremendous needs to find alternative methods for ASC preconditioning. Therefore, this work investigated: (1) the ability of low-dose ultraviolet B (UVB) radiation to stimulate the survival, migration, and tube-forming activity of ASCs in vitro; (2) the ability of UVB preconditioning to enhance the hair growth-promoting capacity of ASCs in vivo; and (3) the mechanism of action for ASC stimulation by UVB. Although high-dose UVB decreased the proliferation of ASCs, low-dose (10 or 20 mJ/cm 2 ) treatment increased their survival, migration, and tube-forming activity. In addition, low-dose UVB upregulated the expression of ASC-derived growth factors, and a culture medium conditioned by UVB-irradiated ASCs increased the proliferation of dermal papilla and outer root sheet cells. Notably, injection of UVB-preconditioned ASCs into C 3 H/HeN mice significantly induced the telogen-to-anagen transition and increased new hair weight in vivo. UVB treatment significantly increased the generation of reactive oxygen species (ROS) in cultured ASCs, and inhibition of ROS generation by diphenyleneiodonium chloride (DPI) significantly attenuated UVB-induced ASC stimulation. Furthermore, NADPH oxidase 4 (Nox4) expression was induced in ASCs by UVB irradiation, and Nox4 silencing by small interfering RNA, like DPI, significantly reduced UVB-induced ROS generation. These results suggest that the primary involvement of ROS generation in UVB-mediated ASC stimulation occurs via the Nox4 enzyme. This is the first indication that a low dose of UVB radiation and/or the control of ROS generation could potentially be incorporated into a novel ASC preconditioning method for hair regeneration.

The Molecular Mechanism Underlying the Proliferating and Preconditioning Effect of Vitamin C on Adipose-Derived Stem Cells

“…The regenerative potential of ASCs and the paracrine effect of ASCs differ according to the stimulators used [12,15,[45][46][47]. For example, hypoxia upregulated VEGF and bFGF, which enhanced wound healing and hair-regenerative potential of ASCs [12].…”

“…An area on the back of 7-week-old C 3 H/HeN mice in the telogen stage of the hair cycle was shaved with clippers and electric shaver, and special care was taken to avoid damaging the bare skin [15,26]. Before injection into the mice, ASCs were treated with vitamin C (200 mM).…”

“…Hypoxia also increases ASC survival, and hypoxia preconditioning upregulated growth factor expression and induced a regenerative potential in animal experiments [12][13][14]. Alternatively, low-dose UVB treatment before transplantation increased the survival and hair growth promoting effect of ASCs in vivo [15]. We previously investigated the key mediators and signaling pathways involved in ASC stimulation under hypoxia, and found that reactive oxygen species (ROS) generation, the PI3K/Akt pathway, the mitogen-activated protein kinase (MAPK) pathway, and miR-210 play key roles in ASC stimulation [16][17][18].…”

Ultraviolet Radiation in Wound Care: Sterilization and Stimulation

“…31 The keratinocytederived vascular endothelial growth factor (VEGF, also known as VPF or vascular permeability factor) provides the major cutaneous angiogenic activity in epidermal keratinocytes and its overexpression results in hyperpermeable dermal capillaries. 32 34 In a previous study, hypoxia through generation of ROS was shown to increase the survival of human ASCs, and the conditioned medium derived from hypoxiapreconditioned ASCs supported endothelial cell survival and endothelial tube formation. 35 Hypoxia preconditioning also enhanced the wound-healing capacities of ASCs.…”

“…36 Low-dose UVB pretreatment of ASCs in vitro, just as in hypoxia preconditioning, induced ASC survival, migration, angiogenesis, and growth factor stimulation and this was attributed to Nox4-induced ROS generation. 34 Upon absorption of UVB photons, 7-dehydrocholesterol located within keratinocytes is converted to previtamin D3, which is then isomerized to vitamin D3 and later on converted to active form of vitamin D-1,25(OH) 2 D. 1,25(OH) 2 D in the skin activates innate immune responses, such as the production of antimicrobial peptides, which can enhance microbial killing and the stimulation of macrophage differentiation and phagocytosis. 37 …”