Chromatin Reprogramming via Contact Guidance-Induced Nuclear Deformation Promotes Stem Cell Differentiation

Abstract

Efficient manipulation of cell fate is important for regenerative engineering applications. Lineage-specific differentiation of stem cells is particularly challenging due to their inherent plasticity. Engineered topographies may alter cellular plasticity through contact guidance. However, the ability to rationally design topographies to regulate phenotypic outcomes has been hindered in part by the lack of tools to quantify nanoscale chromatin structure reorganization in live cells. Herein we use micropillars, molecular, and nanostructural quantification tools to investigate how nuclear morphology in human mesenchymal stem cells (hMSCs) affects chromatin conformation and osteogenic differentiation. We show that micropillar-induced contact guidance is transduced via the cytoskeleton and impacts nuclear architecture, lamin A/C multimerization, histone modifications, and the 3-D conformation of chromatin within packing domains, a key regulator of transcriptional responsiveness. Micropillars repressed expression of genes associated with developmental processes and enhanced lineage-specific responsiveness, thereby decreasing cell plasticity and off-target differentiation, and facilitating osteogenic differentiation of hMSCs. Altogether, these findings reveal that chromatin reprogramming through contact guidance-induced nuclear deformation can be an efficient way to manipulate cell fate.