3D-bioprinted anti-senescence organoid scaffolds repair cartilage defect and prevent joint degeneration via miR-23b/ELOVL5-mediated metabolic rewiring

Osteoarthritis (OA) is the most prevalent degenerative disease worldwide and commonly occurs among the elderly. At present, there is no effective treatment for OA. When OA develops to the end stage, arthroplasty is generally operated to improve the life quality of patients. Targeting senescence has been considered as a therapeutic approach for OA in recent years. In this study, we have identified P16 gene as a novel target for anti-senescence strategy and harnessed small interfering RNA (siRNA) technology to fabricate P16-siRNA encapsulated PLGA microspheres. We combined this with our previously successful three-dimensional (3D) culture of functionally bioengineered chondrogenic synovial mesenchymal stromal cell (SMSC) organoids. This served as the primary component of the bio-ink for 3D bioprinting, culminating in the creation of P16-siRNA PLGA µS and SMSC organoid hydrogel-polymer composite scaffold (PPSOH). Its superior capabilities of cartilage repair were confirmed through in vivo and in vitro experimentations. In the rabbit model of knee cartilage defects, PPSOH not only restored the superior characteristics of native healthy hyaline cartilage but also maintained post-implanted joint function. It prevented development of joint degeneration resulting from cartilage defects by mitigating intra-articular inflammatory responses and cellular senescence. Our usage of miRNA and RNA sequencing reveals that PPSOH targets the miR-23b/ELOVL5 axis and rewired cellular metabolism, therefore regulating glycolysis and fatty acid oxidation. This effectively alleviates cellular senescence, promotes relief from OA, and facilitates cartilage regeneration. PPSOH scaffold could effectively alleviate cellular senescence, foster relief from OA, and facilitate cartilage regeneration. Further experiments disclosed that PPSOH targets the miR-23b/ELOVL5 axis and rewired cellular metabolism by regulating glycolysis and fatty acid oxidation. Therefore, PPSOH could be used as potential therapy for cartilage repair in osteoarthritic patients.