Fig. 7.

HLA-E expression by senescent fibroblasts in human skin during ageing. a Histological sections from healthy donors were stained for DAPI (blue), TelC (red punctate intranuclear), γH2AX S139 (green) and p16^INK4A (white). Telomere-associated γH2AX foci (TAF) are shown (white arrow heads) in non-senescent (NSEN; top panels) and senescent (SEN; bottom panels) cells in the dermis of the human skin. Original image shown in Supplementary Fig. 7E and provided in the Source Data file. Scatterplot showing the relationship between the frequency of p16^INK4A+ cells (b) and donor age (c) with the frequency of TAF⁺ cells in the interstitial dermis of the human skin. d Skin sections were stained for DAPI (blue), TelC (red punctate intranuclear), γH2AX S139 (green) and HLA-E (white). Telomere-associated γH2AX foci (TAF) are shown (white arrow heads) in senescent HLA-E⁺ cells (yellow asterisks) of the human dermis. The signal intensity of TelC and γH2AX along lines (a) and (b) are represented in histogram format and both signals overlap in the senescent, but not the non-senescent cell. e Correlation of HLA-E⁺ cells and TAF⁺ cells in the interstitial dermis of human skin. f Correlation of HLA-E⁺ cells and p16^INK4A+ cells in the interstitial dermis of the human skin. g The frequency of HLA-E⁺ cells present in the superficial dermis of young (n = 4) and old (n = 5) human skin. h The frequency of HLA-E⁺ cells in the TAF⁺ and TAF⁻ populations in the dermis of young (n = 4) and old (n = 5) human skin. The data are represented as mean ± SEM. Statistical significance calculated with Mann–Whitney U test. *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001