Fig. 6.

Impact of nicotine on processes involved in cell stress, damage, and fate and gene expression changes in young and old HAoSMCs. A The response to various concentrations (log₁₀ scale) of aqueous extracts is plotted as the fold change in intensity (log₂ and original scales on left and right y-axes, respectively) in young (filled gray triangles) and old cells (filled black squares) relative to the control (C) of young cells. Statistical analyses: black crosses at the top of the plot indicate statistical differences in pairwise comparisons between young and old cells at a significance level of 0.05. Stars at the bottom of the plot indicate whether the cell response for each treatment condition is statistically different from its respective control for young (gray stars) and old (black stars) cells separately (*p  <  0.05). Points reflect the mean of N independent experiments including n =  2 replicates within each plate. Error bars correspond to their standard error of the mean. B SRPs are visualized as volcano plots, with the magnitude of gene expression changes (x-axis) expressed as the fold change in log₂ scale and the statistical significance (y-axis) represented as − log₁₀ (adjusted p value: FDR; N  =  3–4 independent experiments). The horizontal line represents the statistical significance threshold (FDR) of 0.05. C control; Nico nicotine; O old; Y young