Ultraviolet Radiation‐Induced Skin Aging: The Role of DNA Damage and Oxidative Stress in Epidermal Stem Cell Damage Mediated Skin Aging

Abstract

Skin is the largest human organ. Skin continually reconstructs itself to ensure its viability, integrity, and ability to provide protection for the body. Some areas of skin are continuously exposed to a variety of environmental stressors that can inflict direct and indirect damage to skin cell DNA. Skin homeostasis is maintained by mesenchymal stem cells in inner layer dermis and epidermal stem cells (ESCs) in the outer layer epidermis. Reduction of skin stem cell number and function has been linked to impaired skin homeostasis (e.g., skin premature aging and skin cancers). Skin stem cells, with self-renewal capability and multipotency, are frequently affected by environment. Ultraviolet radiation (UVR), a major cause of stem cell DNA damage, can contribute to depletion of stem cells (ESCs and mesenchymal stem cells) and damage of stem cell niche, eventually leading to photoinduced skin aging. In this review, we discuss the role of UV-induced DNA damage and oxidative stress in the skin stem cell aging in order to gain insights into the pathogenesis and develop a way to reduce photoaging of skin cells.

Effect of Adipose-Derived Stem Cells on Induced Photoaging in the Skin of Adult Guinea Pig: Histological and Immunohistochemical Study

“…The UVB detrimental effects were attributed to the upregulation of mitochondrial cytochrome C which was responsible for UVB-induced reactive oxygen species (ROS) formation and the activation of caspases that initiated a proteolytic cascade leading to UVB-induced cell death [34] . Elevated ROS levels were also claimed to be responsible for premature aging of the epidermal stem cells through damaging both nuclear and mitochondrial DNA with defective DNA repair mechanisms [35] . Disrupted hemidesmosomes detected in the present study was in accordance with previous investigators who explained this effect by secretion of large amounts of matrix metalloproteinase enzymes (MMPs) by dermal fibroblasts.…”

Transportation of Mesenchymal Stem Cells for Clinical Applications

“…There are three types of UVR by wavelength: UV-A (315-400 nm), UV-B (280-315 nm), and UV-C (100-280 nm). UV-A and UV-B can reach the Earth's surface, but the ozone layer ilters out UV-C [33]. Ageing of skin associated with UVR exposure is referred to as photoageing.…”

“…Ageing of skin associated with UVR exposure is referred to as photoageing. Sun-exposed areas of the skin, such as the face and neck, undergo premature ageing [33]. UV-A induces production of reactive oxygen species (ROS) and activates cell cycle checkpoint proteins such as p53 and p21 [34].…”

“…UV-B exposure causes structural rearrangement of nucleotides that leads to defects in DNA strands. The UVR-induced ROS production and DNA damage to epidermal stem cells lead to photoageing [33]. Although there are many reports about the harmful efects of UVR on epidermal stem cells, there is litle information about UVR efects on MSCs.…”

Review of Soybean Phytochemicals and Their Bioactive Properties Relevant for Skin Health

“…The skin is the largest organ of the human body [6], and forms an environmental barrier to protect the body. As perhaps the most important feature of our appearance, the condition of our skin is directly related to perceived attractiveness and health [7].…”