Fractionated Electron Irradiation Induces Human Adipose Tissue Stem Cell Senescence

• Published in: Cytotherapy (Oxford, England) Vol. 27; no. 5; p. e5
• Main Authors: Baranovskii, D., Lyamina, S., Kalish, S., Kozhevnikova, E., Ivanova, T., Kisel, A., Isaeva, E., Govorun, V., Klabukov, I.
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.05.2025
• Subjects: Advanced Basic Science; inflammaging; Irradiation; Other; Senescence; Irradiation; Senescence; inflammaging
• ISSN: 1465-3249
• DOI: 10.1016/j.jcyt.2025.04.010

The cellular and molecular mechanisms underlying aging are currently the subject of increasing interest, with a focus on chronic aseptic nonspecific inflammation linked to aging. Adipose Tissue Stem Cells (ATSCs) influence the immune system through both paracrine signalling and direct intercellular interactions. ATSCs have a limited proliferative capacity and are subject to aging, eventually entering a state of senescence. The aim of this study was to investigate whether fractionated electron irradiation can induce stable senescence in human ATSCs. The study used ATSCs at Passage 8, divided into five groups: an Intact group, Control normoxic group, Control hypoxic group, Irradiated normoxic group and irradiated hypoxic group. Intact group presented as initial cell population and not cultured within experimental study. Irradiated groups were exposed to an electron beam irradiation by a Novac-11 accelerator, administered in two fractions of 3 Gy each, with a 7-day interval between fractions, resulting in a total absorbed dose of 6 Gy; both Control groups were not irradiated. Irradiated and Control groups were cultured for 14 days in a serum-free medium under normoxic (5% carbon dioxide (CO2), 21% oxygen (O2)) or hypoxic (5% CO2, 6.5% O2) conditions. Phenotyping of ATSCs was performed on day 14 of culture for the Control and Irradiated groups and on day 0 for the Intact group. Cellular senescence was assessed by conventional β-galactosidase staining, flow cytometry used to analyze the presence of CD90 and CD105. RNA was extracted for qPCR analysis in each group to quantify the expression of IL-6, IL-8, p16, p21, TGF-β; the housekeeping genes used were Actin-b, RPL0, GUSB. The highest percentage of senescent cells (approximately 60%) was documented in the Irradiated hypoxic group. The percentage of CD90+ and CD105+ cells, as well as the percentage of CD90+CD105+ cells, were significantly lower compared to the Intact group as well as to the Control normoxic group. At 14 days, the expression levels of p16 and p21 in the Irradiated normoxic group did not differ from the Control groups; the expression levels of IL6 and TGF-β1 were higher in the Irradiated groups. Culturing ATSCs in serum-free medium and under hypoxic conditions, that mimic the physiological partial pressure of oxygen in adipose tissue, effectively promotes cellular senescence. Fractionated irradiation is a viable method to induce a stable state of senescence in ATSCs.