Nuclear barrier induction as a new modality of cellular senescence

Blocking of nucleocytoplasmic trafficking is an essential feature of replicative senescence (RS). However, whether nuclear barrier per se causes cellular senescence still remains elusive. Here, we show that nuclear barrier induced by blocking nucleocytoplasmic trafficking, especially nuclear export, elicits RS-like changes in SA-β-gal activity, DNA damage, and expression of cell cycle regulators. Comparative transcriptome analysis revealed that nuclear barrier-induced senescence (NBIS) was most similar in gene expression changes to RS compared to senescence induced by stresses (oxidative stress, DNA damage and oncogene), implying that nuclear barrier induces RS-like physiological senescence-associated changes. Shared senescence-related processes between NBIS and RS included lysosomal degradation, nuclear transport, and translation, resulting in coordinated reduction in transmission of extrinsic signals to nucleus and intracellular protein supply from nucleus. Notably, these processes were conserved in yeast aging. Therefore, we propose NBIS as a novel modality of cellular senescence, representing the fundamental nature of physiological aging in eukaryotes. We performed seven comparisons as follows: 1) RS HDFs (n=3; passage=53) versus young (n=3; passage=12) HDFs (RS/Young); 2) WGA-treated HDFs (n=3) versus young HDFs (n=3) (WGA/Young); 3) LMB-treated HDFs (n=3) versus young HDFs (n=3) (LMB/Young); 4) RCC1 shRNA-treated (n=3) versus control shRNA-treated HDFs (n=3) (RCC1-KD/Control); 5) HDFs overexpressing RasV12 (n=3) versus control ORF (n=3) (RasV12/Control ORF); 6) H2O2-treated HDFs (n=3) versus young HDFs (n=2) (H2O2/Young); and 7) doxorubicin-treated HDFs (n=3) versus young HDFs (n=2) (Doxorubicin/Young), where n indicates the number of replicates for each condition. The comparison 1-3 used the samples of young HDFs in batch 1 as the controls, and the comparison 6-7 used those in batch 3 (see description and characteristics: batch).