Department of Physiology, Christian Medical College, Vellore, 632002, India; Centre for Stem Cell Research, (A unit of inStem, Bengaluru), Christian Medical College, Vellore, 632002, India.
Department of Physiology, Christian Medical College, Vellore, 632002, India.
Acta Histochem. 2021 May;123(4):151713. doi: 10.1016/j.acthis.2021.151713. Epub 2021 Apr 21.
Chondroprogenitors, a promising therapeutic modality in cell-based therapy, are routinely isolated from articular cartilage by fibronectin differential adhesion assay. However, there is paucity of information regarding their biological profile and the lack of a marker that can reliably distinguish them from cultured chondrocytes due to possible dedifferentiation. Since chondroprogenitors have been classified as mesenchymal stem cells(MSCs), the aim of our study was to compare bone marrow-MSCs, chondroprogenitors and chondrocytes, and assess superiority for cartilage repair. An additional objective was to also compare CD49b as a differentiating marker for isolating chondroprogenitors as a recent report demonstrated significantly high expression in the surfaceome of migratory articular chondroprogenitors.
Bone marrow aspirate and articular cartilage was obtained from three osteoarthritic knee joints. Study arms included a) bone marrow-MSCs, b) chondroprogenitors, c) cultured chondrocytes, d) chondrocytes cultured with additional growth factors and e) CD49b + sorted chondroprogenitors. Assessment parameters included population doubling, surface expression for positive, negative MSC markers and potential markers of chondrogenesis (CD29, CD49e, CD49b, CD166 and CD146), RT-PCR for markers of chondrogenesis and hypertrophy and trilineage differentiation.
Chondroprogenitors exhibited efficient chondrogenesis (SOX-9 and COL2A1) and significantly lower tendency for hypertrophy (RUNX2), which was also reflected in trilineage differentiation where progenitors displayed minimal calcified matrix, efficient glycosaminoglycan deposition and high collagen type II uptake. CD49b did not serve as a marker for isolation as sorted chondroprogenitors performed significantly poorer when compared to fibronectin assay derived cells. Emphasis on preclinical studies utilizing progenitors of higher purity is the future direction.
软骨祖细胞是细胞治疗中很有前途的治疗方式，通常通过纤维连接蛋白差异黏附试验从关节软骨中分离出来。然而，由于软骨祖细胞可能发生去分化，关于它们的生物学特性以及缺乏能够可靠地区分它们与培养的软骨细胞的标记物的信息很少。由于软骨祖细胞已被归类为间充质干细胞（MSCs），我们的研究目的是比较骨髓 MSC、软骨祖细胞和软骨细胞，并评估它们在软骨修复方面的优势。另一个目的是比较 CD49b 作为分离软骨祖细胞的分化标记物，因为最近的一份报告表明，它在迁移性关节软骨祖细胞的表面组中表达水平显著升高。
从三个骨关节炎膝关节中获得骨髓抽吸物和关节软骨。研究臂包括：a）骨髓 MSC；b）软骨祖细胞；c）培养的软骨细胞；d）用额外生长因子培养的软骨细胞；e）CD49b+分选的软骨祖细胞。评估参数包括倍增数、阳性和阴性 MSC 标记物以及软骨形成的潜在标记物（CD29、CD49e、CD49b、CD166 和 CD146）的表面表达、软骨形成和肥大的 RT-PCR 以及三系分化。
软骨祖细胞表现出高效的软骨形成（SOX-9 和 COL2A1）和明显较低的肥大倾向（RUNX2），这也反映在三系分化中，其中祖细胞显示出最小的钙化基质、高效的糖胺聚糖沉积和高胶原蛋白 II 摄取。CD49b 不作为分离的标记物，因为与纤维连接蛋白试验分离的细胞相比，分选的软骨祖细胞的性能明显较差。未来的方向是强调利用纯度更高的前体细胞进行临床前研究。
