Bioimaging: An Useful Tool to Monitor Differentiation of Human Embryonic Stem Cells into Chondrocytes

To improve the recovery of damaged cartilage tissue, pluripotent stem cell-based therapies are being intensively explored. A number of techniques exist that enable monitoring of stem cell differentiation, including immunofluorescence staining. This simple and fast method enables changes to be observed during the differentiation process. Here, two protocols for the differentiation of human embryonic stem cells into chondrocytes were used (monolayer cell culture and embryoid body formation). Cells were labeled for markers expressed during the differentiation process at different time points (pluripotent: NANOG, SOX2, OCT3/4, E-cadherin; prochondrogenic: SOX6, SOX9, Collagen type II; extracellular matrix components: chondroitin sulfate, heparan sulfate; beta-catenin, CXCR4, and Brachyury). Comparison of the signal intensity of differentiated cells to control cell populations (articular cartilage chondrocytes and human embryonic stem cells) showed decreased signal intensities of pluripotent markers, E-cadherin and beta-catenin. Increased signal intensities of prochondrogenic markers and extracellular matrix components were observed. The changes during chondrogenic differentiation monitored by evaluation of pluripotent and chondrogenic markers signal intensity were described. The changes were similar to several studies over chondrogenesis. These results were confirmed by semi-quantitative analysis of IF signals. In this research we indicate a bioimaging as a useful tool to monitor and semi-quantify the IF pictures during the differentiation of hES into chondrocyte-like.