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

Area of Science:

• Cell Biology
• Epigenetics
• Biomaterials Science

Background:

• Mesenchymal stem cells (MSCs) respond to biophysical cues, influencing their behavior via mechanotransduction.
• Prolonged ex vivo culture on rigid substrates induces a 'mechanical memory' by causing persistent nuclear YAP localization.
• This mechanical memory can negatively impact MSC function in cell-based therapies.

Purpose of the Study:

• To investigate if transient epigenetic modulation can alter YAP subcellular localization in human bone marrow-derived MSCs.
• To determine if epigenetic modification can overcome the effects of mechanical memory in MSCs.
• To assess the potential of 5-azacitidine (5-Aza) as a method to improve MSC quality for therapeutic applications.

Main Methods:

• Human bone marrow-derived MSCs were treated with 5-azacitidine (5-Aza), a DNA methyltransferase inhibitor.
• YAP subcellular localization was assessed using microscopy.
• RNA sequencing was performed to analyze gene expression changes, particularly related to the extracellular matrix (ECM).
• MSCs were cultured on substrates of varying stiffness to evaluate YAP relocalization dynamics.

Main Results:

• 5-Aza treatment shifted YAP localization from the nucleus to the cytoplasm in MSCs.
• This shift occurred without significant changes in pluripotency markers or neural differentiation potential.
• RNA sequencing revealed down-regulation of ECM-related genes post-5-Aza treatment.
• 5-Aza-treated MSCs demonstrated restored YAP relocalization to the cytoplasm upon transfer to soft substrates, even after prior stiff substrate culture.

Conclusions:

• Transient 5-Aza treatment can partially reverse mechanically induced YAP regulation and alleviate MSC mechanical memory.
• Suppression of ECM production, either by 5-Aza or TGF-β inhibition, promotes cytoplasmic YAP localization.
• Simple, transient 5-Aza administration offers a potential strategy to enhance MSC quality during ex vivo expansion for cell therapies.