Aging‐Regulating Microspheres for Enhancing Mitochondrial Biogenesis in Early Senescence and Clearing Late Senescent Cells

Targeting senescent cells represents a promising strategy for treating degenerative diseases. Within the senescent microenvironment of degenerating tissues, two distinct types of senescent cells coexist: early senescent cells, characterized by functionally reversible oxidative stress, and late senescent cells, which have permanently exited the cell cycle. This study employed membrane proteomics to identify differences in membrane protein expression between early and late senescent nucleus pulposus cells, highlighting aquaporin 1 (AQP1) as a potential marker for oxidatively stressed early senescent cells. Based on this marker, immunoliposomes (Ab‐Lipos) specifically targeting early senescent cells are developed. Through microfluidic technology, Ab‐Lipos and Forkhead Box O4‐D‐ Retro‐Inverso (FOXO4‐DRI) peptides are encapsulated into HAMA/FOXO4‐DRI/Ab‐Lipos hydrogel microspheres. Ab‐Lipos specifically target mitochondrially dysfunctional early senescent cells, delivering ZLN005 to activate the PGC‐1α‐NRF1/2‐TFAM pathway. This activation restores endogenous mitochondrial biogenesis and improves cellular energy metabolism, thereby reversing cellular senescence. The FOXO4‐DRI peptide competitively binds to p53, which is highly expressed in late senescent cells, releasing p53 from functional inhibition. This reactivation restores the p53/BCL‐2/Caspase‐3 signaling pathway, promoting the removal of late senescent cells and reducing the production of senescence‐associated secretory phenotype (SASP) factors. In a rat model of intervertebral disc degeneration, the HAMA/FOXO4‐DRI/Ab‐Lipos hydrogel microspheres effectively mitigated the progression of disc degeneration.