Fig. 1

Sialylation of glycoproteins decreased during the process to senescence in skin fibroblasts. a Mean values of forward scatter (FSC) relative to early-passage (EP) fibroblasts are shown. Results are presented as means ± SD from three independent experiments. b The doubling time of the cells is shown. Results are presented as means ± SD from three independent experiments. c, d Cell surface glycans in EP and late-passage (LP) fibroblasts were analyzed by FACS using lectins. Three independent experiments were performed, and representative results are shown (c). Controls are presented in gray. Mean fluorescent intensities (MFIs) (after recalculation in relation to cell size as described in the Results section) relative to those of EP fibroblasts are shown (d). Results are presented as means ± SD from three or four independent experiments. *P < 0.05, **P < 0.02. e Real-time PCR analysis of NEU1 was performed using cDNA derived from EP and LP fibroblasts. The results are shown after normalization to the values obtained for EP fibroblasts (value = 1). Results are presented as means ± SD from four independent experiments. *P < 0.05. f, g Western blot analysis of NEU1 was performed in EP and LP fibroblasts. The histogram (g) shows the mean densitometric analysis ± SD of NEU1 normalized to the loading control (β-actin). The values were obtained from three independent experiments. h Cell surface NEU1 in EP and LP fibroblasts was analyzed by FACS using anti-NEU1 antibody. Three independent experiments were performed, and representative results are shown. Controls are presented in gray. i MFIs relative to those of EP fibroblasts are shown. Results are presented as means ± SD from three independent experiments