The CRM1 nuclear export receptor controls pathological cardiac gene expression

Area of Science:

• Cardiovascular Biology
• Molecular Cardiology
• Epigenetics

Background:

• Pathological cardiac remodeling involves myocyte hypertrophy, leading to heart failure.
• Subcellular distribution of transcriptional regulators controls pathological cardiac hypertrophy.
• Nuclear export of transcription factors like NFAT and GATA is CRM1-dependent.

Purpose of the Study:

• To investigate the role of histone deacetylase 5 (HDAC5) nuclear export in pathological cardiac hypertrophy.
• To determine if CRM1 mediates HDAC5 nuclear export in response to hypertrophic stimuli.
• To evaluate the therapeutic potential of targeting CRM1-dependent nuclear export.

Main Methods:

• Studied the subcellular localization of HDAC5 in cardiomyocytes under hypertrophic conditions.
• Utilized CRM1 antagonists to block nuclear export of HDAC5.
• Assessed the effects of CRM1 inhibition on pathological gene expression and cardiomyocyte hypertrophy.
• Compared CRM1's role in pathological vs. non-pathological cardiac gene activation.

Main Results:

• HDAC5 is exported from the cardiomyocyte nucleus via a CRM1-mediated pathway in response to hypertrophic signals.
• CRM1 antagonists inhibit agonist-induced HDAC5 nuclear export, repressing pathological gene expression and hypertrophy.
• CRM1 activity is not required for non-pathological cardiac gene activation by thyroid hormone and IGF-1.

Conclusions:

• CRM1 selectively promotes pathological cardiac gene expression by enabling the nuclear export of antihypertrophic factors like HDAC5.
• Targeting CRM1-dependent nuclear export offers a potential therapeutic strategy for heart failure by suppressing maladaptive cardiac remodeling.