Journal: Blood Advances
Article Title: The alarmin interleukin-33 modulates platelet proteome, function, and biogenesis
doi: 10.1182/bloodadvances.2025018363
Figure Lengend Snippet: IL-33 treatment in vivo modifies platelet morphology and activation, expands the MK-biased LT-HSC pool, and enhances platelet release within lung capillaries. (A) Schematic overview of the IL-33 treatment protocol: WT mice received 3 intranasal doses of recombinant human IL-33 or PBS. (B) Flow cytometry analysis of platelet morphology in WT mice following IL-33 or PBS treatment. (C) Quantification of platelet counts by flow cytometry in IL-33- or PBS-treated WT mice. Data are from n = 14 mice per group, collected across 3 independent experiments. (D) Flow cytometry assessment of platelet degranulation, measuring alpha granule (P-selectin) and dense granule (CD63) expression after IL-33 or PBS administration. (E) Plasma levels of sCD40L, measured by ELISA in IL-33–treated or PBS-treated WT mice. (D-E) Data are from n = 8 to 9 mice per group, collected across 2 independent experiments. (F) Quantification of BM LT-HSC, separated into CD41 ˗ (canonical) and CD41 + (MK-biased) populations, shown as a percentage of LSK cells. Data are obtained from n = 22 mice per group, collected across 5 independent experiments. (G) Lung intravital microscopy was performed in PF4-mTmG mice treated with IL-33 or PBS, 24 hours after the first (IL-33 1×) or third (IL-33 3×) administration to assess MKs/proplatelets generating platelets. (H) Representative time-lapse intravital lung microscopy images showing PF4 + small proplatelets and large proplatelet/MK structures releasing platelets within pulmonary capillaries. Scale bar, 50 μm. (I-J) Quantification of proplatelet structures producing platelets per hour per ROI in the lung, categorized as small (<200 platelet volume equivalent), medium (200-1000 platelets), and large (>1000 platelets). (K) Total platelet release per hour across the entire lung. Statistical analysis was performed using t test; # P < .05, ## P < .01. A total of n = 5 to 21 videos were analyzed, collected from 3 to 11 mice per group across 5 independent experiments. ns, not significant. Figure created with biorender.com . Blanchard L. (2026) https://BioRender.com/qdgtyov .
Article Snippet: However, IL-33 mRNA and protein have not been detected in previous platelet transcriptomic or proteomic studies., To resolve these discrepancies, we performed analyses with a polyclonal goat anti-mouse IL-33 antibody (R&D Systems, catalog no. AF3626) that has been validated for immunofluorescence, flow cytometry, and western blot analyses in previous studies , including several studies by our team., , , IL-33 is a nuclear cytokine and the Ab AF3626 stains the nucleus of IL-33 producing cells in WT mice but not in IL-33KO mice.
Techniques: In Vivo, Activation Assay, Recombinant, Flow Cytometry, Expressing, Clinical Proteomics, Enzyme-linked Immunosorbent Assay, Intravital Microscopy, Microscopy