Uncovering the cellular and molecular changes in tendon stem/progenitor cells attributed to tendon aging and degeneration.
Bottom Line: These analyses revealed an intriguing transcriptomal shift in A-TSPC, where the most differentially expressed probesets encode for genes regulating cell adhesion, migration, and actin cytoskeleton.Time-lapse analysis showed that A-TSPC exhibit decelerated motion and delayed wound closure concomitant to a higher actin stress fiber content and a slower turnover of actin filaments.Lastly, based on the expression analyses of microarray candidates, we suggest that dysregulated cell-matrix interactions and the ROCK kinase pathway might be key players in TSPC aging.
Affiliation: Department of Surgery, Experimental Surgery and Regenerative Medicine, Ludwig Maximilians University Munich, Nussbaumstr. 20, 80336, Munich, Germany.Show MeSH
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Mentions: TSPC were successfully isolated from human Achilles tendon biopsies (Table S1) and characterized in vitro to validate their stem/progenitor character. We used FACS and immunocytochemistry to examine the expression of surface antigens and stem cell markers in TSPC based on the studies by Bi et al. (2007), Tempfer et al. (2009), and Mienaltowski et al. (2013). More than 98% of Y-TSPC and A-TSPC were positive for MSC-related surface antigens CD73, CD90, and CD105 (Fig. S1A). They were negative for hematopoietic and endothelial cell antigens CD19, CD34, CD45, and HLA-DRA, thus excluding possible contamination with such cells (Table S2 and S3). TSPC were also positive for STRO-1 (MSC marker), CD146 (pericyte marker), Musashi-1 (muscle, neural, and pericyte markers) (Fig. S1B), and CD44 (MSC marker, Fig.1H). Next, we performed quantitative and semi-quantitative PCR analyses of tendon-related genes, which confirmed the expression of the transcription factors scleraxis, Eya1, and Six1, the tendon marker gene tenomodulin and several extracellular matrix proteins abundant in tendon (collagen types I and III, COMP, decorin, and tenascin C) in both TSPC types (Fig. S1C-E).
Affiliation: Department of Surgery, Experimental Surgery and Regenerative Medicine, Ludwig Maximilians University Munich, Nussbaumstr. 20, 80336, Munich, Germany.