Uniacial Cyclic Stretching Promotes Chromatin Accessibility of Gene Loci Associated with Mesenchymal Stem Cells Morphogenesis and Osteogenesis

Our results showed that UCS induced cell reorientation and actin fibers realignment, and in turn caused nuclear reorientation and deformation. Furthermore, UCS promoted the expression of osteogenic and chondrogenic marker genes. Based on assay for transposase accessible chromatin with high throughput sequencing (ATAC-seq), gene loci with up-regulated chromatin accessibility under UCS were found associate with regulation of cell morphogenesis, ossification, and osteogenic differentiation signaling pathways. These findings demonstrated UCS increased the openness of gene loci associated with cell morphogenesis and osteogenesis as well as the corresponding transcription activities. Moreover, our findings also connect the changes in chromatin accessibility with cell reorientation, nuclear reorientation and deformation. Examination of different chromatin accessbility in mesenchymal stem cells with or without uniacial cyclic stretching