The Impact of Pro-Inflammatory Cytokines on Alternative Splicing Patterns in Human Islets.

Area of Science:

• Immunology
• Molecular Biology
• Endocrinology

Background:

• Alternative splicing (AS) in pancreatic beta cells is a potential mechanism contributing to type 1 diabetes (T1D) pathogenesis.
• AS may generate novel immunogenic epitopes, triggering autoimmune responses against beta cells.

Purpose of the Study:

• To computationally identify and prioritize pathogenic AS events in human islets under inflammatory conditions mimicking T1D.
• To predict RNA binding proteins (RBPs) involved in AS and validate key splicing alterations in T1D models.

Main Methods:

• Computational analysis of AS events in cytokine-treated human islets (IL-1β + IFN-γ).
• K-mer based approach to predict RBPs. ExonImpact tool for predicting structural protein impact.
• Targeted qPCR and single-molecule RNA FISH to validate AS events in human islets and pancreatic tissues.

Main Results:

• Identified 969 AS events, with skipped exons being most common (44.8%).
• 129 AS events predicted to impact protein structure, frequently in MHC Class II-related mRNAs.
• Validated reduced inclusion of Exon5 in HLA-DMB and increased HLA-DMB splicing in T1D patient tissues.
• SRSF2 implicated in 37.2% of pathogenic AS events, including HLA-DMB Exon5 exclusion.

Conclusions:

• Dynamic regulation of AS is involved in the beta cell response to inflammatory signals during T1D.
• Specific AS events, like in HLA-DMB, may contribute to T1D autoimmunity by altering immunogenic epitopes.