2025-12-01 バッファロー大学(UB)
The advanced technology that Jun Qu and his team developed provides a more accurate and specific picture of how insulin production is changing and how the functions of beta cells in the pancreas become compromised at each stage of diabetes.
<関連情報>
- https://www.buffalo.edu/news/releases/2025/12/Jun-Qu-diabetes-research.html
- https://pubs.acs.org/doi/10.1021/acs.analchem.5c03256
抗体カクテルベースの免疫親和性LC-MS法は、循環プロインスリンプロテオフォームおよびCペプチドの超高感度かつ堅牢な定量を可能にしました An Antibody Cocktail-Based Immunoaffinity-LC-MS Method Enabled Ultra-Sensitive and Robust Quantification of Circulating Proinsulin Proteoforms and C-Peptide
Qingqing Shen,Wang Cao,Ming Zhang,Tai-Tu Lin,Gabriela S. F. Monaco,Lorenz Nierves,Tujin Shi,Cornelia Boeser,Scott Peterman,Carmella Evans-Molina,Emily K. Sims,Wei-Jun Qian,and Jun Qu
Analytical Chemistry Published: August 28, 2025
DOI:https://doi.org/10.1021/acs.analchem.5c03256
Abstract
Accurately measuring circulating proinsulin proteoforms is crucial for clinical investigation of diabetes, but was previously not feasible owing to limited assay specificity/sensitivity. Here we devised a highly sensitive LC-MS-based strategy to quantify intact proinsulin, des-31,32 and des-64,65 proinsulin, and C-peptide in circulation. The method involves: (i) quantitative, robust affinity capture using an optimized antibody cocktail, eliminating the severe quantitative bias across multiple proteoforms typically introduced when using a single antibody; (ii) Lys-C digestion producing unique signature peptides for each proteoform, and (iii) trapping-nano-LC coupled with FAIMS/dCV-MS for an ultrasensitive analysis. The selective trapping/delivery ensured sensitive/selective analysis of the targets while achieving excellent analytical robustness that is critical for clinical assays, and the FAIMS/dCV substantially reduces baseline noise/interferences, further enhancing S/N. The assay achieved exceptional sensitivity, with serum LOQs of 1.7, 2.3, and 3.6 pg/mL respectively for intact-proinsulin, des-31,32 and des-64,65, representing the first assay capable of sensitively quantifying these major circulating proinsulin proteoforms. We applied this assay to 78 subjects, including autoantibody positive (n = 20) and new-onset type 1 diabetes (T1D, n = 19) with respective age/sex/BMI-matched controls, enabling the first accurate profiling of proinsulin proteoforms in clinical groups. The assay results demonstrated a clear separation of control and new-onset T1D groups that a parallel total-proinsulin ELISA assay fails to capture. Furthermore, distinct expression patterns in relative abundance ratios among proteoforms were observed across clinical groups. This assay may provide valuable insights into the β-cell functions and the onset/progression of diabetes and other associated conditions. Moreover, the strategy is broadly applicable to targeted measurement of other biomarker proteoforms.
