Reduced thymic IL-4 impairs negative T cell selection in nonobese diabetic mice
Alexis N. Cattin-Roy, … , Adam G. Schrum, Habib Zaghouani
Alexis N. Cattin-Roy, … , Adam G. Schrum, Habib Zaghouani
Published December 2, 2024
Citation Information: J Clin Invest. 2024;134(23):e163417. https://doi.org/10.1172/JCI163417.
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Research Article Autoimmunity

Reduced thymic IL-4 impairs negative T cell selection in nonobese diabetic mice

Abstract

Type 1 diabetes (T1D) develops spontaneously despite functional antigen presentation machinery in the thymus and a perceptible central tolerance process. We found that intrathymic enrichment with IL-4 fine tunes signaling through the IL-4/IL-13 heteroreceptor (HR) in early thymic progenitors (ETPs), augments negative selection of self-reactive T cells, sustains a diverse T cell repertoire devoid of clones expressing disease-associated T cell receptor (TCR) genes, and protects the nonobese diabetic (NOD) mouse from T1D. Indeed, optimal IL-4 activates STAT transcription factors to program ETP fate decision toward CD11c+CD8α+ dendritic cells (DCs) agile in negative T cell selection and clonal deletion of diabetogenic T cells. However, due to diminished invariant natural killer T (iNKT) 2 cell frequency in the NOD thymus, IL-4 is as suboptimal level, metering STAT activation to program ETP fate decision toward the T cell lineage leading to diminished negative selection, a clonally restricted TCR repertoire, and manifestation of spontaneous T1D. These insights uncover yet another interplay by which IL-4 affects T1D.

Authors

Alexis N. Cattin-Roy, Kimberly G. Laffey, Luan B. Le, Adam G. Schrum, Habib Zaghouani

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Figure 3

Diminished IL-4 in the NOD thymus parallels with a lower frequency of iNKT cells.

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Diminished IL-4 in the NOD thymus parallels with a lower frequency of iN...
(A) HR+ETPs from B6 and NOD mice were analyzed ex vivo for phosphorylation of different isoforms of STAT1 and STAT6 transcription factors. The upper panels show a representative experiment while the lower panels show the mean ± SD of results compiled from 3 experiments for each strain. B shows mRNA expression for Il7r (left panel), Notch1 (middle panel), and Cebpa (right panel) in HR+ETPs from NOD (circles) and B6 (squares) mice. RQ, relative quality. The results were compiled from 3 or 4 experiments. (C and D) Total thymocytes from 6–8 week-old mice were used to extract RNA or stimulated with PMA/Ionomycin. RQ, relative quality. (C) mRNA expression was analyzed by RT-PCR while (D) IL-4 and IL-13 secretion was determined by ELISA. The results were compiled from 3 experiments for each strain. (E) Percent of iNKT cells that stain positive for CD3 and α-GalCer analog tetramer (iNKT-tet) among fresh CD8-depleted thymocytes. (F) Number of iNKT cells in NOD (circles) and B6 (square) thymi. Each symbol represents an individual mouse. (G) The contour plots show intracellular IL-4 production by sorted iNKT cells (from 5 mice) that were stimulated with anti-CD3/anti-CD28. The graph on the right panel shows the mean number ± SD of iNKT cells staining for intracellular IL-4 from both strains. The results were compiled from 3 experiments for each strain. H shows the percentage of different subsets of iNKT cells including iNKT1 (CD122+ CD4+/– ICOS–), iNKT2 (CD122– CD4+ ICOS+), and iNKT17 (CD122– CD4– ICOS+) among all iNKT cells as determined by cell surface staining. The results were compiled from 4 experiments for each strain. I shows the percentage of intracellular IL-4–producing iNKT subsets among total iNKT cells. The data was compiled from 3 experiments. *P < 0.05, **P < 0.01, ***P < 0.001 as determined by 2-tailed, unpaired Student’s t test.