Exosomes derived from mature chondrocytes facilitate subcutaneous stable ectopic chondrogenesis of cartilage progenitor cells

Abstract

BackgroundDeveloping cartilage constructed with the appropriate matrix composition and persistent chondrogenesis remains an enduring challenge in cartilage defects. Cartilage progenitor cell (CPC)-based tissue engineering has attracted recent attention because of its strong chondrogenic differentiation capacity. However, due to the lack of a suitable chondrogenic niche, the clinical application of CPC-regenerated cartilage in the subcutaneous environment remains a challenge. In this study, exosomes derived from chondrocytes (CC-Exos) were used to provide the CPC constructs with a cartilage signal in subcutaneous environments for efficient ectopic cartilage regeneration.MethodsRabbit CPC-alginate constructs were prepared and implanted subcutaneously in nude mice. CC-Exos were injected into the constructs at the same dose (30 μg exosomes per 100 μL injection) after surgery and thereafter weekly for a period of 12 weeks. Exosomes derived from bone mesenchymal stem cells (BMSC-Exos) were used as the positive control. The mice in the negative control were administered with the same volume of PBS. At 4 and 12 weeks after implantation, the potential of CC-Exos and BMSC-Exos to promote chondrogenesis and stability of cartilage tissue in a subcutaneous environment were analyzed by histology, immunostaining, and protein analysis. The influences of BMSC-Exos and CC-Exos on chondrogenesis and angiogenic characteristics in vitro were assessed via coculturing with CPCs and human umbilical vein endothelial cells.ResultsThe CC-Exos injection increased collagen deposition and minimized vascular ingrowth in engineered constructs, which efficiently and reproducibly developed into cartilage. The generated cartilage was phenotypically stable with minimal hypertrophy and vessel ingrowth up to 12 weeks, while the cartilage formed with BMSC-Exos was characterized by hypertrophic differentiation accompanied by vascular ingrowth. In vitro experiments indicated that CC-Exos stimulated CPCs proliferation and increased expression of chondrogenesis markers while inhibiting angiogenesis.ConclusionsThese findings suggest that the novel CC-Exos provides the preferable niche in directing stable ectopic chondrogenesis of CPCs. The use of CC-Exos may represent an off-the-shelf and cell-free therapeutic approach for promoting cartilage regeneration in the subcutaneous environment.

Articular chondrocyte-derived exosomes promote cartilage differentiation of human umbilical cord mesenchymal stem cells by activation of autophagy

“…In our study, we found that C-EXOs could promote the chondrogenesis of HUCMSCs and exert a therapeutic effect on cartilage defects, suggesting that the C-EXOs a pleasant micro-ecological environment for cartilage repair. This nding is consistent with previous studies that exosomes derived from mature chondrocytes can promote the formation of ectopic cartilage in the subcutaneous environment of cartilage progenitor cells 18 . Exosomes, as important paracrine components, are involved in maintaining normal physiological functions, mediating inter-cell communication, and inducing changes in cell functions and processes by delivering various types of bioactive microRNAs, proteins, and unique gene products 9,10,24 .…”

“…These ndings indicate that exosomes retain the multiple biological activities of homologous cells 17 . Another study found that exosomes derived from rabbit chondrocytes can promote the formation of ectopic cartilage in the subcutaneous environment of cartilage progenitor cells 18 , suggesting that chondrocyte-derived exosomes play a crucial role in chondrogenesis of cartilage progenitor cells. Thus, human articular chondrocytes-derived exosomes (C-EXOs) may be promising substitutes for TGF-β to guide chondrogenic differentiation of MSCs.…”

A Role for Exosomes in Craniofacial Tissue Engineering and Regeneration

“…Additionally, chondrocyte-derived exosomes directed the experimental subcutaneous formation of cartilage-like tissues. It was suggested that maintaining a favorable chondrogenic "niche" was the result of antiangiogenic factors of chondrogenic exosomes (Chen et al, 2018). Many exosomes possess immunomodulatory function that is essential to the process of cartilage regeneration (Toh et al, 2017).…”

Exosomes in osteoarthritis and cartilage injury: advanced development and potential therapeutic strategies

“…They found both exosomes attenuated OA in the mouse OA model, but iMSC-Exos had a superior therapeutic effect compares to SMMMSC derived exosomes, and iMSC-Exos exerted a stronger effect on chondrocyte migration and proliferation in vitro. In another study, Chen et al found that exosomes derived from chondrocytes (CC-Exos) increased collagen deposition and minimized vascular ingrowth in engineered constructs, and efficiently and reproducibly developed into cartilage, while the BMSC-Exos treated tissue engineered construct was characterized with hypertrophic differentiation accompanied by vascular ingrowth [43] . In vitro, CC-Exos could stimulate cartilage progenitor cells proliferation and significantly promoted chondrogenesis-related factors at the mRNA and protein levels.…”