Title

Heterogeneity of Islet-Infiltrating IL-21+ CD4 T Cells in a Mouse Model of Type 1 Diabetes.

Document Type

Article

Publication Date

4-1-2023

Keywords

JMG, SS1, Mice, Animals, Diabetes Mellitus, Type 1, CD4-Positive T-Lymphocytes, Mice, Inbred NOD, Islets of Langerhans

JAX Source

J Immunol. 2023;210(7):935-46

ISSN

1550-6606

PMID

36762954

DOI

https://doi.org/10.4049/jimmunol.2200712

Grant

This work was supported by the National Institute of Diabetes and Digestive and Kidney Diseases Grants DK107541 and AI144360 and National Institute of Allergy and Infectious Diseases Grant DK121747 (to Y.-G.C.), National Institute of Diabetes and Digestive and Kidney Diseases Grant DK097605 (to A.M.G. and Y.-G.C.), and National Institute of Diabetes and Digestive and Kidney Diseases Grant DK118786 (to A.E.C.).

Abstract

IL-21 is essential for type 1 diabetes (T1D) development in the NOD mouse model. IL-21-expressing CD4 T cells are present in pancreatic islets where they contribute to T1D progression. However, little is known about their phenotype and differentiation states. To fill this gap, we generated, to our knowledge, a novel IL-21 reporter NOD strain to further characterize IL-21+ CD4 T cells in T1D. IL-21+ CD4 T cells accumulate in pancreatic islets and recognize β cell Ags. Single-cell RNA sequencing revealed that CD4 T effector cells in islets actively express IL-21 and they are highly diabetogenic despite expressing multiple inhibitory molecules, including PD-1 and LAG3. Islet IL-21+ CD4 T cells segregate into four phenotypically and transcriptionally distinct differentiation states, that is, less differentiated early effectors, T follicular helper (Tfh)-like cells, and two Th1 subsets. Trajectory analysis predicts that early effectors differentiate into both Tfh-like and terminal Th1 cells. We further demonstrated that intrinsic IL-27 signaling controls the differentiation of islet IL-21+ CD4 T cells, contributing to their helper function. Collectively, our study reveals the heterogeneity of islet-infiltrating IL-21+ CD4 T cells and indicates that both Tfh-like and Th1 subsets produce IL-21 throughout their differentiation process, highlighting the important sources of IL-21 in T1D pathogenesis.

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