Directing iPSC Differentiation into iTenocytes Using Combined Scleraxis Overexpression and Cyclic Loading

This study developed a strategy to generate tenocyte-like cells from induced pluripotent stem cell–derived mesenchymal stromal cells (iMSCs) through the combined use of stable scleraxis (Scx) overexpression and cyclic mechanical loading. While Scx overexpression alone promoted early tenogenic marker expression, the addition of uniaxial cyclic stretch significantly enhanced cytoskeletal alignment, extracellular matrix deposition, and upregulation of late tendon markers. Cyclic loading induced pronounced nuclear reorientation, actin filament alignment perpendicular to the loading axis, and increased collagen-I deposition, indicating mechanically guided maturation toward a tenocyte phenotype. The results demonstrate that synergistic biological and mechanical cues are required to efficiently direct iPSC-derived cells toward functional tendon-like lineages.