Chondral Differentiation of Induced Pluripotent Stem Cells Without Progression Into the Endochondral Pathway

Abstract

A major problem with chondrocytes derived in vitro from stem cells is undesired hypertrophic degeneration, to which articular chondrocytes (ACs) are resistant. As progenitors of all adult tissues, induced pluripotent stem cells (iPSCs) are in theory able to form stable articular cartilage. In vitro differentiation of iPSCs into chondrocytes with an AC-phenotype and resistance to hypertrophy has not been demonstrated so far. Here, we present a novel protocol that succeeded in deriving chondrocytes from human iPSCs without using pro-hypertrophic bone-morphogenetic-proteins. IPSC-chondrocytes had a high cartilage formation capacity and deposited two-fold more proteoglycans per cell than adult ACs. Importantly, cartilage engineered from iPSC-chondrocytes had similar marginal expression of hypertrophic markers (COL10A1, PTH1R, IBSP, ALPL mRNAs) like cartilage from ACs. Collagen X was barely detectable in iPSC-cartilage and 30-fold lower than in hypertrophic cartilage derived from mesenchymal stromal cells (MSCs). Moreover, alkaline phosphatase (ALP) activity remained at basal AC-like levels throughout iPSC chondrogenesis, in contrast to a well-known significant upregulation in hypertrophic MSCs. In line, iPSC-cartilage subjected to mineralizing conditions in vitro showed barely any mineralization, while MSC-derived hypertrophic cartilage mineralized strongly. Low expression of Indian hedgehog (IHH) like in ACs but rising BMP7 expression like in MSCs suggested that phenotype stability was linked to the hedgehog rather than the bone morphogenetic protein (BMP) pathway. Taken together, unlimited amounts of AC-like chondrocytes with a high proteoglycan production reminiscent of juvenile chondrocytes and resistance to hypertrophy and mineralization can now be produced from human iPSCs in vitro. This opens new strategies for cartilage regeneration, disease modeling and pharmacological studies.

Cartilage from human-induced pluripotent stem cells: comparison with neo-cartilage from chondrocytes and bone marrow mesenchymal stromal cells

“…Based on a pre-set threshold for expression levels of COL2A1, 79% of the hiCPC pellets deposited good neocartilage, while, in line with previous studies (Diederichs et al 2019;Diederichs and Tuan 2014), chondrogenesis with the hiMSCs was successful in 54% of the pellets. Among others, hiCPC-derived neo-cartilage showed significantly (13-fold) higher expression of COL2A1 compared to that from hPACs, which was in accordance with the COL2 protein expression as detected with immunohistochemistry.…”

Single-cell RNA seq analysis identifies the biomarkers and differentiation of chondrocyte in human osteoarthritis

“…Some researchers found SIN-1 could induce oxidative stress lead to necrosis in HTCs [34,31]. For cell proliferation and growth factor, some growth factor such as COL10A1 and ALP were high expression in HTCs and promoted the proliferation of HTCs [35,36]. Therefore, the candidate marker genes of HTCs may have close relationships with proliferation and differentiation of HTCs in OAs.…”

Engineering Prostate Cancer from Induced Pluripotent Stem Cells—New Opportunities to Develop Preclinical Tools in Prostate and Prostate Cancer Studies

“…For example, generation of human adipocytes (white, brown and beige) from iPSCs, exhibiting mature morphological and functional properties characteristic of in vivo fat tissue, has shed light on adipogenesis and provided a platform for the development of obesity-and diabetes-related therapies [85,86]. TGFβ-driven differentiation of human iPSCs into chondrocytes capable of forming cartilage has opened up new strategies for cartilage tissue engineering, disease modelling and pharmacological drug studies for osteoarthritis [87]. In contrast, the adult human heart harbours several different cell types.…”