CD138 expression is a molecular signature but not a developmental requirement for RORγt+ NKT17 cells
Shunqun Luo, Juntae Kwon, Assiatu Crossman, Pyong Woo Park, Jung-Hyun Park
Shunqun Luo, Juntae Kwon, Assiatu Crossman, Pyong Woo Park, Jung-Hyun Park
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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 1

CD138 expression in thymocyte subpopulations.

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CD138 expression in thymocyte subpopulations. (A) CD138 expression was a...
(A) CD138 expression was assessed on BALB/c thymocyte subsets, identified by their distinct CD4, CD8, and TCRβ expression. Results are representative of 3 independent experiments. (B) CD138 expression among DN thymocytes (left). CD138+CD3+ DN thymocytes are mostly CD1dTet+ iNKT cells but also contain conventional αβ and γδ T cells (right). Results represent 3 independent experiments (total 6 BALB/c mice). (C) The dot plot and histogram show the identification and CD138 expression of thymic γδ T cells, respectively. Data represent 3 independent experiments (total 8 BALB/c mice). (D) The dot plot and histogram show the identification of iNKT cells and CD138 expression among thymic iNKT cells, respectively. Data summarize 4 independent experiments (total 9 BALB/c mice). (E) Individual iNKT subsets were identified by intranuclear transcription factor staining (dot plots), which were then assessed for CD138 expression (histograms). Numbers in dot plots indicate frequencies of each iNKT subset among CD24loCD1d Tet+ thymic iNKT cells. The results represent 3 independent experiments (total 4 BALB/c mice). (F) Dot plots show iNKT cell frequencies in Rorc–/– and WT littermate BALB/c thymocytes. Results represent 3 independent experiments with a total of 5 Rorc–/– and 4 littermate mice. (G) Thymic γδ T cell generation in Rorc–/– BALB/c mice. Dot plots are representative, and the bar graph shows the summary of γδ T cell frequencies in Rorc–/– and WT littermate BALB/c thymocytes. Results are from 3 independent experiments with a total of 5 Rorc–/– and 4 WT littermate mice. (H) Histogram shows the frequency of CD138+ γδ T cells in Rorc–/– and WT littermate BALB/c thymocytes. The results represent 3 independent experiments with a total of 5 Rorc–/– and 4 littermate mice. All data are presented as mean ± SEM. P values were determined by unpaired Student’s t test. **P < 0.01.