PQQ Modulates Cell Cycle and DNA Replication Programs to Alleviate Replicative Senescence in Human Umbilical Cord Mesenchymal Stromal Cells.

Abstract

Human Umbilical Cord-derived Mesenchymal Stromal Cells (hUC-MSCs) represent a promising candidate for regenerative medicine, though their therapeutic potential is constrained by replicative senescence. Pyrroloquinoline quinone (PQQ), a redox-active coenzyme, has been reported to protect against cellular aging. However, its precise role and mechanism of action in mitigating replicative senescence of hUC-MSCs remain to be elucidated. This study employed an integrated approach of phenotypic screening and transcriptomic profiling to systematically evaluate the anti-senescence effects of PQQ on replicatively senescent hUC-MSCs. Our results indicated that PQQ treatment enhanced proliferative capacity, reduced senescence-associated β-galactosidase (SA-β-gal) activity, and attenuated G1 phase cell cycle arrest. Moreover, PQQ improved mitochondrial membrane potential, reduced intracellular reactive oxygen species (ROS) accumulation, and attenuated telomere attrition. RNA sequencing analysis suggests that PQQ treatment appears to alleviate senescence-related transcriptional features, which is consistent with the observed phenotypic improvements. Gene Set Enrichment Analysis (GSEA) revealed a significant upregulation of pathways governing cell cycle progression and DNA replication following PQQ intervention. Key Driver Analysis (KDA) further identified regulators within these pathways, including PLK1, MCM5, and CDC6. Subsequent qPCR validation showed that the expression of these genes, which are critical for DNA replication initiation and mitotic progression, was downregulated in senescent cells and increased following PQQ treatment. In conclusion, the effect of PQQ on the replicative senescence of hUC-MSCs may be related to the upregulation of genes associated with the cell cycle and DNA replication.