Expression of Apoptosis- and Autophagy-Related Genes in Passaged Normal Human Dermal Fibroblasts = Expression of Apoptosis- and Autophagy-Related Genes in Passaged Normal Human Dermal Fibroblasts

다국어 초록 (Multilingual Abstract)

Purpose: Apoptosis, autophagy, and replication senescence play important roles in cellular responses. This study was performed to investigate the expression of apoptosis- and autophagy-related genes with increasing passage number in normal human dermal fibroblasts.
Methods: The levels of mRNA were examined by real-time polymerase chain reaction and expression levels of proteins were measured by western blotting analysis.
Results: Among the cell cycle-related genes, the levels of cyclin D1, p16, and p21 mRNA were increased at passage number 10 compared to passage number 5, while all were decreased at passage number 15. The level of p27 mRNA was reduced with increasing number of passages. Among apoptosis-related genes, the levels of Bcl-2, Bax, caspase-3, and p53 protein were enhanced with increasing number of passages. The levels of PARP protein were decreased. Among autophagy-related genes, the levels of LC3 II, mTOR p62, Atg5, and AMPK protein were significantly enhanced with increasing number of passages, while levels of Akt protein were slightly enhanced and levels of Beclin 1 protein were reduced at passage number 15.
Conclusion: Our data suggested that aging normal fibroblasts undergo G1 arrest due to increased cell cycle gene expression during cellular senescence, with enhanced apoptosis and autophagy occurring in association with increasing passage number.