CELF1 Downregulation Promotes Cardiomyocyte Hypertrophy via Regulating Alternative Splicing of Tead1

Area of Science:

• Molecular Biology
• Cardiovascular Research
• Gene Regulation

Background:

• The RNA-binding protein CELF1 is essential for normal cardiac development.
• The specific function of CELF1 in cardiomyocyte hypertrophy remains largely unknown.
• Understanding CELF1's role is critical for addressing cardiac pathologies.

Purpose of the Study:

• To investigate the impact of acute CELF1 knockdown on cardiomyocyte hypertrophy.
• To identify alternative splicing events regulated by CELF1 in cardiomyocytes.
• To elucidate the molecular mechanisms underlying CELF1's function in cardiac cells.

Main Methods:

• Neonatal rat cardiomyocytes (NRCMs) were subjected to CELF1 knockdown using siRNAs.
• Hypertrophy was quantified by cell size measurements and analysis of hypertrophic marker gene expression (qPCR, Western blot).
• RNA sequencing (RNA-seq) was employed to identify global alternative splicing changes, with subsequent mechanistic studies in HeLa cells.

Main Results:

• CELF1 knockdown significantly increased cardiomyocyte size and upregulated key hypertrophic markers.
• RNA-seq analysis revealed altered alternative splicing patterns upon CELF1 depletion, notably a shift in Tead1 splicing.
• Tead1 splicing shifted from the full-length Tead1-L isoform to the exon 4-skipped Tead1-S isoform; CELF1 interacts with hnRNPC and influences m6A abundance.

Conclusions:

• CELF1 plays a regulatory role in controlling hypertrophic phenotypes within cardiomyocytes.
• The alternative splicing of the Tead1 transcription factor is a key mechanism modulated by CELF1.
• These findings highlight CELF1 as a potential therapeutic target for cardiac hypertrophy.