Single-Islet Proteomics Maps Pseudo-Temporal Islet Immune Responses and Dysfunction in Stage 1 Type 1 Diabetes

Area of Science:

• Endocrinology and Metabolism
• Immunology
• Proteomics

Background:

• Progressive beta-cell dysfunction is key in type 1 diabetes (T1D) pathogenesis.
• Molecular drivers of early T1D remain unclear, with limited understanding of islet microenvironment heterogeneity.
• Single-cell RNA sequencing provides transcript-level data but lacks spatial proteomic insights.

Purpose of the Study:

• To define in situ protein signatures of pseudo-temporal islet dysfunction in early T1D.
• To profile intra-donor islet heterogeneity using a single-islet proteomics workflow.
• To investigate molecular mechanisms underlying early T1D development.

Main Methods:

• Applied a single-islet proteomics workflow to profile individual islets.
• Analyzed approximately 100 islets per donor from three stage 1 T1D cases and matched controls.
• Utilized proteome-wide analysis to identify molecular signatures and pathways associated with islet dysfunction.

Main Results:

• Consistent proteomic patterns reflecting pseudo-time progression of islet immune responses and beta-cell dysfunction were observed within donors.
• Identified pathways, including extracellular matrix remodeling and mRNA processing, associated with immune activation and beta-cell function loss.
• Demonstrated robust proteome-wide evidence for the progression of islet dysfunction.

Conclusions:

• Single-islet spatial proteomics is valuable for examining islet heterogeneity in T1D.
• Findings provide a resource for investigating early T1D mechanisms and identifying novel functional candidates.
• The study highlights the utility of proteomics in understanding pseudo-temporal islet dysfunction in T1D.