Cartilage tissue engineering using differentiated and purified induced pluripotent stem cells

Abstract

The development of regenerative therapies for cartilage injury has been greatly aided by recent advances in stem cell biology. Induced pluripotent stem cells (iPSCs) have the potential to provide an abundant cell source for tissue engineering, as well as generating patient-matched in vitro models to study genetic and environmental factors in cartilage repair and osteoarthritis. However, both cell therapy and modeling approaches require a purified and uniformly differentiated cell population to predictably recapitulate the physiological characteristics of cartilage. Here, iPSCs derived from adult mouse fibroblasts were chondrogenically differentiated and purified by type II collagen (Col2)-driven green fluorescent protein (GFP) expression. Col2 and aggrecan gene expression levels were significantly up-regulated in GFP+ cells compared with GFP− cells and decreased with monolayer expansion. An in vitro cartilage defect model was used to demonstrate integrative repair by GFP+ cells seeded in agarose, supporting their potential use in cartilage therapies. In chondrogenic pellet culture, cells synthesized cartilagespecific matrix as indicated by high levels of glycosaminoglycans and type II collagen and low levels of type I and type X collagen. The feasibility of cell expansion after initial differentiation was illustrated by homogenous matrix deposition in pellets from twicepassaged GFP+ cells. Finally, atomic force microscopy analysis showed increased microscale elastic moduli associated with collagen alignment at the periphery of pellets, mimicking zonal variation in native cartilage. This study demonstrates the potential use of iPSCs for cartilage defect repair and for creating tissue models of cartilage that can be matched to specific genetic backgrounds.chondrocyte | bone morphogenetic proteins | transforming growth factor-beta | cartilage micromechanics | cartilage regeneration

Immune Modulation to Improve Tissue Engineering Outcomes for Cartilage Repair in the Osteoarthritic Joint

“…122 iPSCs generated from the reprogramming of mouse fibroblasts have been successfully differentiated toward the chondrogenic linage, and shown to integrate with native cartilage tissue and produce cartilage matrix in an in vitro cartilage defect model. 123 Furthermore, chondrogenic differentiation of MSC-like cells derived from human iPSCs has been shown by Guzzo et al to result in a cellular phenotype that more closely resembles articular chondrocytes, compared with undifferentiated iPSCs. 124 iPSCderived MSCs inhibit lymphocyte proliferation and suppress Th2-associated cytokine production in a similar manner to MSCs, and have been found to elicit a comparable immunomodulatory effect in a mouse model of allergic inflammation.…”

Pluripotent stem cells and their use in hearing loss

“…A typical example of cartilage regenerative medicine is autologous chondrocyte implantation, in which chondrocytes isolated from the patient's cartilage or derived from mesenchymal stem cells are cultured and injected into the cartilage defects in liquid or gel form. The mesenchymal stem cells inhibit the release of proinflammatory cytokines and are helpful in cartilage repair and osteoarthritis (Diekman et al, 2012). The ear and nose cartilage tissue has high regeneration capacity and future therapy with iPS may not be needed for these problems.…”

“…However, the capacity of articular cartilage for repair and regeneration is extremely poor. iPS cells have the potential to provide an abundant cell source for tissue engineering and the generation of patient-matched in vitro models to study genetic and environmental factors in cartilage repair (Diekman et al, 2012).…”

Induced Pluripotent and Mesenchymal Stem Cells as a Promising Tool for Articular Cartilage Regeneration

“…Moreover, in this study the stem cell derived-cells did not reveal the tumorigenic risk in a mouse fracture model. In the other study, the usefulness of murine iPSCs in cartilagerepair therapies was demonstrated [57]. After initial chondrogenic differentiation, iPSCs were treated with type II collagen-driven green fluorescent protein (GFP) and the GFP positive cells were seeded onto 1% agarose, delivered to the defect and chondrogenic differentiation was successfully performed for 21 days.…”

“…These cells differentiate into several cell lineages including osteogenic and chondrogenic [8,9]. More recently described induced pluripotent stem cells (iPSCs) have the potential to differentiate into somatic cells, including chondrocytes [10][11][12].…”