DNA Damage Response After Ionizing Radiation Exposure in Skin Keratinocytes Derived from Human-Induced Pluripotent Stem Cells

Abstract

Epidermal cells are positioned on the outermost layer of skin and thus risk exposure to environmental factors. The biological effect of ionizing radiation on the skin tissue is a significant problem in medical applications such as radiation therapy for cancer treatment. In this study, we established humaninduced pluripotent stem cells and skin keratinocytes and analyzed DNA damage response and cell senescence after exposure to ionizing radiation.Purpose: Epidermal cells are positioned on the body surface and thus risk being exposed to genotoxic stress, including ionizing radiation (IR), ultraviolet rays, and chemical compounds. The biological effect of IR on the skin tissue is a significant problem for medical applications such as radiation therapy. Keratinocyte stem cells and progenitors are at risk for IR-dependent tumorigenesis during radiation therapy for cancer treatment. To elucidate the molecular mechanism of genome stability in epidermal cells, we derived skin keratinocytes from human-induced pluripotent stem cells (iPSCs) and analyzed their DNA damage response (DDR). Methods and Materials: Skin keratinocytes were derived from iPSCs and designated as first-(P1), second-(P2), and third-(P3) passage cells to compare the differentiation states of DDR. After 2 Gy gamma-ray exposure, cells were immunostained with DNA double-strand break markers g-H2AX/53BP1 and cell senescence markers p16/p21 for DDR analysis. DDR protein expression level, cell survival, and apoptosis were analyzed by western blotting, WST-8 assay and TUNEL assay, respectively. DDR of constructed 3D organoid modeling was also analyzed. Results: P1, P2, and P3 keratinocytes were characterized with keratinocyte markers keratin 14 and p63 using immunofluorescence, and all cells were positive to both markers. Derived keratinocytes showed high expression of integrin a6 and CD71 (real-time (qRT)-PCR ratio: iPSCs: integrin a6: 1.

<p>Aptamer-Conjugated Gold Nanoparticles Targeting Epidermal Growth Factor Receptor Variant III for the Treatment of Glioblastoma</p>

“…Interestingly, treatment with U2-AuNP can decrease the expression level of 53BP1 (binding protein 1) and the phosphorylation level of ATM and Chk2, which are critical in the response to DNA damage. [38][39][40] In recent years, exposure to gold nanoparticles has been reported to cause transient DNA damage due to the generation of alkali-labile sites and oxidative stress with a decrease in glutathione. 41,42 However, the phosphorylation level of H2A.X showed no change after treatment with U2-AuNP 24 hr.…”

A Role for Neutral Sphingomyelinase in Wound Healing Induced by Keratinocyte Proliferation upon 1α, 25-Dihydroxyvitamin D3 Treatment

“…The epidermis, and therefore keratinocites, have the potential risk of being exposed to traumatic damage; genotoxic stress, including chemical compounds; ionizing radiation; ultraviolet rays [6]; and inflammatory agents [7], or having severe cutaneous adverse reactions to drugs [8].…”

Assessment of Chromosomal Damage in Umbilical Blood Lymphocytes of Newborns from Kragujevac in Central Serbia Born 18 Years after Environmental Contamination

“…The most research on cytogenetic damage in humans has focused on exposures to ionizing radiation (Miyake et al 2019;Tubic Vukajlovic et al 2021), heavy metals (Yadav et al 2019;Husain and Mahmood 2020) and PCBs (Wang et al 2018). There is not much data on the longterm effects of environmental exposure to contamination PCBs.…”