Institute of Bioengineering and Nanotechnology, A*STAR, #04-01, 31 Biopolis Way, 138669 Singapore, Singapore; Department of Biomedical Engineering, National University of Singapore, 9 Engineering Drive 1, EA #03-12, Singapore 117575, Singapore.
Institute of Bioengineering and Nanotechnology, A*STAR, #04-01, 31 Biopolis Way, 138669 Singapore, Singapore; Mechanobiology Institute, National University of Singapore, T-Lab, #10-01, 5A Engineering Drive 1, Singapore 117411, Singapore.
Biomaterials. 2015 May;50:87-97. doi: 10.1016/j.biomaterials.2015.01.019. Epub 2015 Feb 16.
Heterogeneity in human pluripotent stem cell (PSC) fates is partially caused by mechanical asymmetry arising from spatial polarization of cell-cell and cell-matrix adhesions. Independent studies have shown that integrin and E-cadherin adhesions promote opposing differentiation and pluripotent fates respectively although their crosstalk mechanism in modulating cell fate heterogeneity remains unknown. Here, we demonstrated that spatial polarization of integrin and E-cadherin adhesions in a human PSC colony compete to recruit Rho-ROCK activated myosin II to different localities to pattern pluripotent-differentiation decisions, resulting in spatially heterogeneous colonies. Cell micropatterning was used to modulate the spatial polarization of cell adhesions, which enabled us to prospectively determine localization patterns of activated myosin II and mesoendoderm differentiation. Direct inhibition of Rho-ROCK-myosin II activation phenocopied E-cadherin rather than integrin inhibition to form uniformly differentiated colonies. This indicated that E-cadherin was the primary gatekeeper to differentiation progression. This insight allows for biomaterials to be tailored for human PSC maintenance or differentiation with minimal heterogeneity.
人多能干细胞（PSC）命运的异质性部分是由细胞-细胞和细胞-基质黏附的空间极化引起的机械不对称性造成的。独立的研究表明，整合素和 E-钙黏蛋白黏附分别促进相反的分化和多能命运，尽管它们在调节细胞命运异质性方面的串扰机制尚不清楚。在这里，我们证明了人 PSC 集落中整合素和 E-钙黏蛋白黏附的空间极化竞争招募 Rho-ROCK 激活的肌球蛋白 II 到不同的位置，以形成多能-分化决定，从而导致空间异质的集落。细胞微图案化用于调节细胞黏附的空间极化，这使我们能够前瞻性地确定激活的肌球蛋白 II 和中胚层分化的定位模式。Rho-ROCK-肌球蛋白 II 的直接抑制作用模拟了 E-钙黏蛋白而不是整合素抑制作用，从而形成均匀分化的集落。这表明 E-钙黏蛋白是分化进展的主要守门员。这一见解使得生物材料可以针对人 PSC 的维持或分化进行定制，以最小的异质性。
