The nuclear import of the transcription factor MyoD is reduced in mesenchymal stem cells grown in a 3D micro-engineered niche

Emanuela Jacchetti,Valentina Parodi,Jose Felix Rodriguez Matas,Ramin Nasehi,Giulio Cerullo,Roberto Osellame,Alessandro Negro,Diego Albani,Lucia Boeri,Manuela Teresa Raimondi

doi:10.1038/s41598-021-81920-2

Abstract

Smart biomaterials are increasingly being used to control stem cell fate in vitro by the recapitulation of the native niche microenvironment. By integrating experimental measurements with numerical models, we show that in mesenchymal stem cells grown inside a 3D synthetic niche both nuclear transport of a myogenic factor and the passive nuclear diffusion of a smaller inert protein are reduced. Our results also suggest that cell morphology modulates nuclear proteins import through a partition of the nuclear envelope surface, which is a thin but extremely permeable annular portion in cells cultured on 2D substrates. Therefore, our results support the hypothesis that in stem cell differentiation, the nuclear import of gene-regulating transcription factors is controlled by a strain-dependent nuclear envelope permeability, probably related to the reorganization of stretch-activated nuclear pore complexes.

Highlights

In the last 2 decades, stem cells have generated a considerable interest in biomedicine with many potential applications such as regenerative and personalized medicine
Spatial organization of focal adhesions (FA) and actin filaments in Mesenchymal stem cells (MSCs) adhering to the Nichoid artificial niche
Immunofluorescence images show the cell morphology and cellular architecture of MSCs grown in the Nichoid with respect to cells grown on glass flat substrate, which we consider as the experimental 2D control (Control)

Summary

Introduction

In the last 2 decades, stem cells have generated a considerable interest in biomedicine with many potential applications such as regenerative and personalized medicine. Other techniques control cell adhesion on novel materials, either by modifying the material’s stiffness or by patterning the substrate with engineered micro/nanoscale features such as pits, protrusions, channels, and p illars[16,17]. The innovative approach of our study is to use a scaffold enabling the cells to self-organize into a three-dimensional configuration allowing a more realistic study of the nuclear import flows than in any 2D cell adhesion configuration. This scaffold is a micro-fabricated substrate, produced by two-photon polymerization technique of a biocompatible, inert and mechanically stable p hotoresin[19]. In this paper, these substrates will be called “Nichoid” for convenience

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