PhD The Chinese University of Hong Kong (CUHK), Hong Kong
Abstract: A key feature of osteoarthritis is the depletion of glycosaminoglycans (GAGs), leading to impaired cartilage hydration, reduced compressive strength, and disrupted chondrocyte homeostasis. Stem cell-based tissue engineering holds promise for cartilage regeneration. To mimic the GAG-rich extracellular matrix (ECM) of native cartilage, we have developed a biomimetic scaffold, aminated collagen-GAG (aCol-GAG), allowing precise control over the GAG content (glycosaminoglycan-to-hydroxyproline ratio, GAG/HYP). Here, human mesenchymal stem cells(hMSCs) from commercial sources and human chondrocytes isolated from patients were expanded and encapsulated in scaffolds with different GAG incorporation, including Col, Col/aCol-GAG, and aCol-GAG with GAG/HYP ratios of 0, 2:1, and 5:1, respectively. Upon chondrogenic differentiation of hMSCs or encapsulation of human chondrocytes, histological and biochemical evaluations of the chondrogenic microtissues were performed to analyse cell viability, chondrogenic phenotype, and ECM deposition on days 7, 14 and 21. Immunohistochemical staining revealed that chondrocytes in GAG/HYP rich scaffolds (aCol-GAG, GAG:HYP = 5:1) exhibited greater type-II collagen expression at later time points as compared with Col (no GAG) and Col/aCol-GAG (low GAG) groups. Live-Dead staining revealed high cell viability. This work demonstrated the importance of engineering the GAG content of scaffolds in engineered chondrogenic microtissues. Delineating the cell-matrix interactions that lead to such phenotype changes in future investigations will contribute to better understanding of matrix niche engineering in tissue engineering and regenerative medicine.
Funding Source: This work was supported by Research Impact Fund (R7036-20) from RGC and ITF (ITS/293/21) from ITC, of the Hong Kong SAR government.
