MATERIALS AND METHODS: Human adipose-derived stem cells at passage 4 were evaluated by flow cytometry to examine the expression of surface markers. These adipose-derived stem cells were tested for adipogenic and osteogenic differentiation capacity. Ribonucleic acid was extracted from the cells for quantitative polymerase chain reaction analysis to determine the expression levels of chondrogenic genes after chondrogenic induction.
RESULTS: Human adipose-derived stem cells were strongly positive for the mesenchymal markers CD90, CD73, CD44, CD9, and histocompatibility antigen and successfully differentiated into adipogenic and osteogenic lineages. The human adipose-derived stem cells aggregated and formed a dense matrix after chondrogenic induction. The expression of chondrogenic genes (collagen type II, aggrecan core protein, collagen type XI, COMP, and ELASTIN) was significantly higher after the first week of induction. However, a significantly elevated expression of collagen type X was observed after three weeks of chondrogenic induction.
CONCLUSION: Human adipose-derived stem cells retain stem cell characteristics after expansion in culture to passage 4 and serve as a feasible source of cells for cartilage regeneration. Chondrogenesis in human adipose-derived stem cells was most prominent after one week of chondrogenic induction.
RESULTS: Several ascending and descending monotonic key genes were identified by Monotonic Feature Selector. The identified descending monotonic key genes are related to stemness or regulation of cell cycle while ascending monotonic key genes are associated with the functions of mesangial cells. The TFs were arranged in a co-expression network in order of time by Time-Ordered Gene Co-expression Network (TO-GCN) analysis. TO-GCN analysis can classify the differentiation process into three stages: differentiation preparation, differentiation initiation and maturation. Furthermore, it can also explore TF-TF-key genes regulatory relationships in the muscle contraction process.
CONCLUSIONS: A systematic analysis for transcriptomic profiling of MSC differentiation into mesangial cells has been established. Key genes or biomarkers, TFs and pathways involved in differentiation of MSC-mesangial cells have been identified and the related biological implications have been discussed. Finally, we further elucidated for the first time the three main stages of mesangial cell differentiation, and the regulatory relationships between TF-TF-key genes involved in the muscle contraction process. Through this study, we have increased fundamental understanding of the gene transcripts during the differentiation of MSC into mesangial cells.
METHODS: We compared the ability of Dulbecco's Modified Eagle's Medium/F12 (DMEM/F12) and Alpha Minimum Essential Medium (α-MEM) with Glutamax (GL) (α-MEM/GL) to expand hUCM cells. For this purpose, hUCM cells were cultured in plates containing different culture media supplemented with 10% fetal bovine serum (FBS). Culture dishes were left undisturbed for 10-14 days to allow propagation of the newly formed hUCM cells. The expansion properties, CD marker expression, differentiation potential, population doubling time (PDT) and cell activity were compared between the two groups.
RESULTS: The hUCM cells harvested from each group were positive for MSC markers, including CD44, CD90 and CD105, while they were negative for the hematopoietic cell surface marker CD34. Differentiation into adipogenic and osteogenic lineages was confirmed for both treatments. Cell activity was higher in the α-MEM/GL group than the DMEM/F12 group. PDT was calculated to be 60 h for the DMEM/F12 group, while for the α-MEM/GL group it was 47 h.
CONCLUSIONS: Our data reveal that α-MEM/GL with 10% FBS supports hUCM cell growth more strongly than DMEM/F12 with 10% FBS.