Articles by Joong-Myung Lee in JoVE
A Protocol to Acquire the Degenerative Tenocyte from Humans Soo-Hong Han*1, Hyung Kyung Kim*2, Jong-Ho Ahn*1, Dong Hyeon Lee3, Minjung Baek1, Geunhee Ye1, Joong-Myung Lee1, Kyunghoon Min4, Chihoon Oh1, Soonchul Lee1 1Department of Orthopaedic Surgery, CHA Bundang Medical Center, CHA University School of Medicine, 2Department of Pathology, Kyung Hee University Hospital at Gangdong, Kyung Hee University School of Medicine, 3Department of Physiology, CHA University School of Medicine, 4Department of Rehabilitation, CHA Bundang Medical Center, CHA University School of Medicine In vitro use of degenerative tenocytes is essential when investigating the efficacy of novel treatment on tendinopathy. However, most research studies use only the animal model or a healthy tenocyte. We propose the following protocol to isolate human degenerative tenocytes during surgery.
Other articles by Joong-Myung Lee on PubMed
Enhancement of Matrix Metalloproteinase-2 (MMP-2) As a Potential Chondrogenic Marker During Chondrogenic Differentiation of Human Adipose-Derived Stem Cells International Journal of Molecular Sciences. | Pubmed ID: 27322256 Human adipose-derived stem cells (hASCs) have a capacity to undergo adipogenic, chondrogenic, and osteogenic differentiation. Recently, hASCs were applied to various fields including cell therapy for tissue regeneration. However, it is hard to predict the direction of differentiation of hASCs in real-time. Matrix metalloproteinases (MMPs) are one family of proteolytic enzymes that plays a pivotal role in regulating the biology of stem cells. MMPs secreted by hASCs are expected to show different expression patterns depending on the differentiation state of hASCs because biological functions exhibit different patterns during the differentiation of stem cells. Here, we investigated proteolytic enzyme activity, especially MMP-2 activity, in hASCs during their differentiation. The activities of proteolytic enzymes and MMP-2 were higher during chondrogenic differentiation than during adipogenic and osteogenic differentiation. During chondrogenic differentiation, mRNA expression of MMP-2 and the level of the active form of MMP-2 were increased, which also correlated with Col II. It is concluded that proteolytic enzyme activity and the level of the active form of MMP-2 were increased during chondrogenic differentiation, which was accelerated in the presence of Col II protein. According to our findings, MMP-2 could be a candidate maker for real-time detection of chondrogenic differentiation of hASCs.
Down-Regulation of Transglutaminase 2 Stimulates Redifferentiation of Dedifferentiated Chondrocytes Through Enhancing Glucose Metabolism International Journal of Molecular Sciences. | Pubmed ID: 29112123 Expansion of chondrocytes for repair of articular cartilage can lead to dedifferentiation, making it difficult to obtain a sufficient quantity of chondrocytes. Although previous studies have suggested that culture in a three-dimensional environment induces redifferentiation of dedifferentiated chondrocytes, its underlying mechanisms are still poorly understood in terms of metabolism compared with a two-dimensional environment. In this study, we demonstrate that attenuation of transglutaminase 2 (TG2), a multifunctional enzyme, stimulates redifferentiation of dedifferentiated chondrocytes. Fibroblast-like morphological changes increased as TG2 expression increased in passage-dependent manner. When dedifferentiated chondrocytes were cultured in a pellet culture system, TG2 expression was reduced and glycolytic enzyme expression up-regulated. Previous studies demonstrated that TG2 influences energy metabolism, and impaired glycolytic metabolism causes chondrocyte dedifferentiation. Interestingly, TG2 knockdown improved chondrogenic gene expression, glycolytic enzyme expression, and lactate production in a monolayer culture system. Taken together, down-regulation of TG2 is involved in redifferentiaton of dedifferentiated chondrocytes through enhancing glucose metabolism.