3D environment modulates persistent lamin distribution and the biomechanical signature of the nucleus.

The interplay between cells and their surrounding microenvironment drives multiple cellular functions, including migration, proliferation, and cell fate transitions. The nucleus is a mechanosensitive organelle that adapts external mechanical and biochemical signals provided by the environment into nuclear changes with functional consequences for cell biology. However, the morphological and functional changes of the nucleus induced by 3D extracellular signals remain unclear. Here, we demonstrated that cells derived from 3D conditions conserve changes from cell confinement and show an aberrant nuclear morphology and localization of lamin B1, even in the absence of cellular confinement. We found that actin polymerization and protein kinase C (PKC) activity mediate the abnormal distribution of lamin B1 in 3D conditions-derived cells. These cells present altered chromatin compaction, gene transcription and cellular functions such as cell viability and migration. By combining biomechanical techniques and single-nucleus analysis, we have determined that the nucleus from 3D conditions-derived cells shows a different mechanical behavior and biophysical signature than the nucleus from control cells. Together, our work substantiates novel insights into how the extracellular environment alters the cell biology by promoting permanent changes in the chromatin, morphology, lamin B1 distribution, and the mechanical response of the nucleus.