Figure 1.
Lamin B1 loss and senescence in UV-exposed keratinocytes in vitro. (a) Representative western blot showing lamin B1 (LMNB1), lamin A (LMNA) and lamin C (LMNC) levels in primary keratinocytes exposed to increasing doses of UVB, in the presence of a plate covered in non-SPF base cream (left panels) or SPF50+ sunscreen (right panels). (b) Quantification of LMNB1 and LMNA/C intensity (normalized to GAPDH and no UV-treated controls; n = 3 different keratinocyte lines; n.s.; non-significant). (c) Representative immunofluorescence images of LMNB1 (green) and LMNA/C (purple) expression in 0.14 J/cm2 UVB-treated and SPF50+ sunscreen-protected keratinocytes (actin, red; DAPI, blue). Bars, 10 µm. Right panels: Quantification of LMNB1 and LMNA/C levels. n = 3 different keratinocyte lines; ***P < 0.001 n.s.; non-significant. (d) Representative phase contrast (phase) and bright-field (BF) images of senescence-associated beta-galactosidase (SA-β-gal) staining in 0.14 J/cm2 UVB-treated and SPF50 + sunscreen-protected keratinocytes. Bars, 20 µm. Right panel: Quantification of SA-β-gal-positive cells. n = 3 different keratinocyte lines; all graphs show mean ± SD, ***P < 0.001.