Integrative Stem Cell Center, China Medical University Hospital, Taichung 404, Taiwan.
Drug Development Center, Institute of Translational Medicine and New Drug Development, School of Medicine, China Medical University, Taichung 406, Taiwan.
Cells. 2022 Oct 21;11(20):3324. doi: 10.3390/cells11203324.
It has been known that senescence-associated secretory phenotype (SASP) triggers senescence of the surrounding normal cells. However, SASP signaling regarding mesenchymal stromal cell aging remains to be fully elucidated. Therefore, the present study aimed to clarify the molecular mechanism of late (passage) MSC-induced paracrine SASP-mediated senescence of early (passage) MSCs during ex vivo expansion. Here, we conducted an extensive characterization of senescence features in bone-marrow (BM)-derived MSCs from healthy human donors. Late MSCs displayed an enlarged senescent-like morphology, induced SASP-related proinflammatory cytokines (IL-1α and IL-8), and reduced clonogenic capacity and osteogenic differentiation when compared to early MSCs. Of note, paracrine effects of SASP-related IL-1α and IL-8 from late MSCs induced cellular senescence of early MSCs via an NF-κB-dependent manner. Moreover, cellular senescence of early MSCs was promoted by the synergistic action of IL-1α and IL-8. However, inhibition of NF-κB by shRNA transfection or using inhibitors in early MSCs blocked early MSCs cellular senescence caused by paracrine SASP of late MSCs. In conclusion, these findings reveal that late MSCs display features of senescence and that, during ex vivo expansion, SASP-related proinflammatory cytokines contribute to activate a cellular senescence program in early MSCs that may ultimately impair their functionality.
衰老相关分泌表型 (SASP) 可引发周围正常细胞衰老，这一点已广为人知。然而，关于间充质基质细胞衰老的 SASP 信号仍有待充分阐明。因此，本研究旨在阐明在体外扩增过程中晚期（传代）MSC 诱导的旁分泌 SASP 介导早期（传代）MSC 衰老的分子机制。在此，我们对来自健康供体的骨髓（BM）来源 MSC 的衰老特征进行了广泛的表征。与早期 MSC 相比，晚期 MSC 呈现出增大的衰老样形态，诱导 SASP 相关促炎细胞因子（IL-1α 和 IL-8），并降低克隆形成能力和成骨分化能力。值得注意的是，晚期 MSC 的 SASP 相关细胞因子 IL-1α 和 IL-8 的旁分泌作用通过 NF-κB 依赖性方式诱导早期 MSC 发生细胞衰老。此外，IL-1α 和 IL-8 的协同作用促进了早期 MSC 的细胞衰老。然而，早期 MSC 中 NF-κB 的抑制通过 shRNA 转染或使用抑制剂可阻断晚期 MSC 旁分泌 SASP 引起的早期 MSC 细胞衰老。总之，这些发现表明晚期 MSC 表现出衰老特征，并且在体外扩增过程中，SASP 相关的促炎细胞因子有助于激活早期 MSC 的细胞衰老程序，这可能最终损害其功能。
