Sca-1 is involved in the adhesion of myosphere cells to αVβ3 integrin

• Main Authors: Ashley Penvose, Karen A. Westerman
• Format: Article
• Language: English
• Published: The Company of Biologists 2012-07-01
• Series: Biology Open
• Subjects: αVβ3 integrin; Sca-1; Myosphere; Muscle stem cells
• Online Access: http://bio.biologists.org/content/1/9/839

Summary A myosphere cell is a unique type of muscle stem cell that is able to maintain its pre-myogenic state in culture over time. These cells are propagated in culture as free-floating, non-adherent spheres. We believe that the 3-dimensional adhesive cell-cell interactions involved in maintaining the sphere-like myosphere structures are also involved in maintaining their longevity in culture. We found that Sca-1, which is highly expressed by myosphere cells, plays a role in the growth and the formation of the myospheres. In comparing adhesion molecules expressed by 3-dimensionally grown myosphere cells to those expressed by 2-dimensionally grown primary myoblasts, we found that there was a distinct difference in the expression of β3 integrin. Upon further investigation we discovered that there is an adhesive interaction between Sca-1+ cells and αVβ3 integrin. Here we show that Sca-1+ cells (myosphere cells and NIH3T3 cells) adhere to αVβ3 integrin and that Sca-1− cells (primary myoblasts) do not adhere. The interaction between Sca-1 and αVβ3 integrin was confirmed using antibody blocking, shRNA knockdown of Sca-1 in Sca-1+ cells, and by expressing Sca-1 cDNA in Sca-1− cells, which demonstrated that the level of adhesion of these cells to αVβ3 integrin was dependent on the presence of Sca-1. Additionally, we found that the co-expression of Sca-1 and β3 resulted in significantly greater adhesion of Sca-1+ cells to αVβ3 integrin. In conclusion, our data indicate that Sca-1 is involved in maintaining the 3-dimensional myosphere cell-cell contacts and that Sca-1 is involved in the binding of cells to αVβ3 integrin.