Characterization of the m⁶A Epitranscriptome in Fibroblast Senescence

Area of Science:

• Epitranscriptomics
• Molecular Biology
• Aging Research

Background:

• Cell senescence is a key process in aging and disease, involving growth arrest and altered gene expression.
• N6-methyladenosine (m6A) is a crucial RNA modification regulating gene expression, but its role in senescence is not fully understood.

Purpose of the Study:

• To investigate the global m6A RNA modification landscape in proliferating versus senescent human fibroblasts.
• To understand how m6A patterns change during cellular senescence and affect senescence-associated pathways.

Main Methods:

• Epitranscriptomic microarray analysis to map m6A modifications.
• m6A-crosslinking and immunoprecipitation followed by sequencing (CLIP-Seq) to identify m6A sites.
• Analysis of gene expression and correlation with m6A levels, including manipulation of METTL3.

Main Results:

• Global m6A levels remained stable, but specific transcripts showed altered methylation in senescent cells, particularly in cell cycle, DNA repair, and inflammation pathways.
• m6A preferentially shifted to 3'-untranslated regions (UTRs) in senescent cells, correlating positively with transcript abundance.
• m6A was enriched in mRNAs encoding senescence-associated secretory phenotype (SASP) factors; METTL3 inhibition decreased SASP mRNA stability (e.g., IL6).

Conclusions:

• m6A plays a selective role in fine-tuning the senescent transcriptome, particularly SASP factor expression.
• These findings offer insights into the epitranscriptomic regulation of senescence.
• m6A represents a potential therapeutic target for age-related diseases influenced by senescent cells.