Isoform Usage as a Distinct Regulatory Layer Driving Nutrient-Responsive Metabolic Adaptation

Transcriptome modulation is essential for metabolic adaptation to nutrient environments. However, the role of isoform usage, a crucial transcriptome component, is not yet fully understood. This study outlines the landscape of isoform usage modulations across major metabolic organs in both mice and monkeys, spanning diverse metabolic states. Our in-depth analysis identifies numerous isoform-usage events, intricately influenced by nutrient challenges and largely independent of gene expression regulation. Comparative analyses of mice and monkeys highlight hundreds of conserved isoform events that exhibit consistent responses to nutrient challenges across species and correlate with human metabolic traits. When analysing splicing factor-binding motifs in nutrient-regulated events, HuR emerges as the predominant orchestrator of the isoform network in adipocytes, which is validated using an adipose tissue-specific knockout and an Ap2-promoter-driven transgenic mouse model. In summary, our results offer a comprehensive perspective on isoform usage in metabolic regulation, setting a platform for future functional inquiries.