CD138 expression is a molecular signature but not a developmental requirement for RORγt+ NKT17 cells
Shunqun Luo, … , Pyong Woo Park, Jung-Hyun Park
Shunqun Luo, … , Pyong Woo Park, Jung-Hyun Park
Published September 22, 2021
Citation Information: JCI Insight. 2021;6(18):e148038. https://doi.org/10.1172/jci.insight.148038.
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Research Article Immunology

CD138 expression is a molecular signature but not a developmental requirement for RORγt+ NKT17 cells

Abstract

Invariant NKT (iNKT) cells are potent immunomodulatory cells that acquire effector function during their development in the thymus. IL-17–producing iNKT cells are commonly referred to as NKT17 cells, and they are unique among iNKT cells to express the heparan sulfate proteoglycan CD138 and the transcription factor RORγt. Whether and how CD138 and RORγt contribute to NKT17 cell differentiation, and whether there is an interplay between RORγt and CD138 expression to control iNKT lineage fate, remain mostly unknown. Here, we showed that CD138 expression was only associated with and not required for the differentiation and IL-17 production of NKT17 cells. Consequently, CD138-deficient mice still generated robust numbers of IL-17–producing RORγt+ NKT17 cells. Moreover, forced expression of RORγt significantly promoted the generation of thymic NKT17 cells, but did not induce CD138 expression on non-NKT17 cells. These results indicated that NKT17 cell generation and IL-17 production were driven by RORγt, employing mechanisms that were independent of CD138. Therefore, our study effectively dissociated CD138 expression from the RORγt-driven molecular pathway of NKT17 cell differentiation.

Authors

Shunqun Luo, Juntae Kwon, Assiatu Crossman, Pyong Woo Park, Jung-Hyun Park

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Figure 2

iNKT cell development in CD138-deficient mice.

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iNKT cell development in CD138-deficient mice. (A) Identification of th...
(A) Identification of thymic iNKT cells in Sdc1–/– BALB/c mice. The dot plots are representative (left), and the iNKT frequency and number graphs show the summary (right) of 8 independent experiments with a total of 13 Sdc1–/– and 12 WT littermate BALB/c mice. Total thymocyte numbers are shown on top of the dot plots as mean ± SEM. Numbers in the box show frequencies of iNKT cells among total thymocytes. (B) iNKT subset distribution in Sdc1–/– BALB/c thymocytes. The frequencies of NKT1, NKT2, and NKT17 cells were determined by T-bet versus PLZF and RORγt versus PLZF expression. The dot plots are representative, and the graphs show the summary of 7 independent experiments with a total of 12 Sdc1–/– and 11 WT littermate BALB/c mice. (C) Thymic NKT2 and NKT17 cell numbers were determined in Sdc1–/– BALB/c thymocytes. The results show the summary of 7 independent experiments with a total of 12 Sdc1–/– and 11 WT littermate BALB/c mice. (D) Phenotypic analysis of Sdc1–/– NKT17 cells. Thymic NKT17 in Sdc1–/– and WT littermate BALB/c mice was assessed for CD138, PLZF, and RORγt expression. Histograms represent 7 independent experiments with a total of 12 Sdc1–/– and 11 WT littermate BALB/c mice. (E) IL-17 production by PLZF+ innate cells in Sdc1–/– BALB/c thymocytes. Intracellular IL-17 was assessed among PLZF+ cells of freshly isolated Sdc1–/– BALB/c thymocytes upon PMA and ionomycin stimulation for 5 hours. Dot plots are representative, and the graph shows the summary of 3 independent experiments with a total of 4 Sdc1–/– and 4 WT littermate BALB/c mice. All data are presented as mean ± SEM. P values were determined by unpaired 2-tailed Student’s t test. *P < 0.05; NS, not significant.