# 5-Azacitidine Partially Resets the Subcellular Localization of YAP in Human Bone Marrow-Derived Mesenchymal Stem Cells

## TL;DR

Treating mesenchymal stem cells with 5-azacitidine helps reset their response to mechanical cues, potentially improving their use in therapies.

## Contribution

Transient 5-azacitidine treatment partially resets mechanical memory in MSCs by modulating YAP localization and ECM gene expression.

## Key findings

- 5-azacitidine shifts YAP localization toward the cytoplasm in MSCs without affecting pluripotency markers.
- RNA-seq shows broad downregulation of extracellular matrix-related genes after 5-azacitidine exposure.
- 5-azacitidine-treated MSCs restore YAP relocalization on soft substrates despite prior expansion on stiff surfaces.

## Abstract

What are the main findings?
Transient 5-azacitidine partially resets mechanically sustained nuclear YAP localization in human bone marrow-derived MSCs.RNA-seq indicates broad downregulation of extracellular matrix-related genes after 5-azacitidine exposure.

Transient 5-azacitidine partially resets mechanically sustained nuclear YAP localization in human bone marrow-derived MSCs.

RNA-seq indicates broad downregulation of extracellular matrix-related genes after 5-azacitidine exposure.

What are the implications of the main findings?
Epigenetic modulation may represent a simple strategy to attenuate culture-induced mechanical memory during ex vivo expansion.This approach may improve consistency of mechanosensitive YAP regulation during MSC preparation for therapeutic applications.

Epigenetic modulation may represent a simple strategy to attenuate culture-induced mechanical memory during ex vivo expansion.

This approach may improve consistency of mechanosensitive YAP regulation during MSC preparation for therapeutic applications.

Mesenchymal stem cells (MSCs) sense biophysical cues from their microenvironment, which regulate cytoskeletal organization and the nuclear–cytoplasmic distribution of the mechanotransducer Yes-associated protein (YAP), thereby shaping cellular behavior. Prolonged ex vivo culture on non-physiologically rigid substrates induces persistent nuclear YAP localization, a phenomenon often referred to as mechanical memory. We therefore examined whether transient epigenetic modulation could modulate YAP subcellular localization in human bone marrow-derived MSCs. Treatment with the DNA methyltransferase inhibitor 5-azacitidine (5-Aza) shifted YAP localization toward the cytoplasm in MSCs, without overt changes in pluripotency marker expression or neural differentiation capacity. RNA sequencing revealed broad down-regulation of extracellular matrix (ECM)-related genes following 5-Aza treatment. Independent suppression of ECM production via TGF-β signaling similarly promoted cytoplasmic YAP localization. When subsequently transferred to soft substrates, 5-Aza–treated MSCs restored YAP relocalization despite prior expansion on stiff surfaces. Together, these findings suggest that transient 5-Aza treatment can partially alleviate mechanically induced YAP regulation associated with mechanical memory. Thus, simple and transient administration of 5-Aza may offer a practical means to improve the quality of MSCs during ex vivo expansion for cell-based therapies.