CXCL12+ fibroblastic reticular cells in lymph nodes facilitate immune tolerance by regulating T cell–mediated alloimmunity
Yuta Yamamura, Gianmarco Sabiu, Jing Zhao, Sungwook Jung, Andy J. Seelam, Xiaofei Li, Yang Song, Marina W. Shirkey, Lushen Li, Wenji Piao, Long Wu, Tianshu Zhang, Soyeon Ahn, Pilhan Kim, Vivek Kasinath, Jamil R. Azzi, Jonathan S. Bromberg, Reza Abdi
Yuta Yamamura, Gianmarco Sabiu, Jing Zhao, Sungwook Jung, Andy J. Seelam, Xiaofei Li, Yang Song, Marina W. Shirkey, Lushen Li, Wenji Piao, Long Wu, Tianshu Zhang, Soyeon Ahn, Pilhan Kim, Vivek Kasinath, Jamil R. Azzi, Jonathan S. Bromberg, Reza Abdi
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Research Article Immunology

CXCL12+ fibroblastic reticular cells in lymph nodes facilitate immune tolerance by regulating T cell–mediated alloimmunity

Abstract

Fibroblastic reticular cells (FRCs) are the master regulators of the lymph node (LN) microenvironment. However, the role of specific FRC subsets in controlling alloimmune responses remains to be studied. Single-cell RNA sequencing (scRNA-Seq) of naive and draining LNs (DLNs) of heart-transplanted mice and human LNs revealed a specific subset of CXCL12hi FRCs that expressed high levels of lymphotoxin-β receptor (LTβR) and are enriched in the expression of immunoregulatory genes. CXCL12hi FRCs had high expression of CCL19, CCL21, indoleamine 2,3-dioxygenase (IDO), IL-10, and TGF-β1. Adoptive transfer of ex vivo–expanded FRCs resulted in their homing to LNs and induced immunosuppressive environments in DLNs to promote heart allograft acceptance. Genetic deletion of LTβR and Cxcl12 in FRCs increased alloreactivity, abrogating the effect of costimulatory blockade in prolonging heart allograft survival. As compared with WT recipients, CXCL12+ FRC–deficient recipients exhibited increased differentiation of CD4+ T cells into Th1 cells. Nano delivery of CXCL12 to DLNs improved allograft survival in heart-transplanted mice. Our study highlights the importance of DLN CXCL12hi FRCs in promoting transplant tolerance.

Authors

Yuta Yamamura, Gianmarco Sabiu, Jing Zhao, Sungwook Jung, Andy J. Seelam, Xiaofei Li, Yang Song, Marina W. Shirkey, Lushen Li, Wenji Piao, Long Wu, Tianshu Zhang, Soyeon Ahn, Pilhan Kim, Vivek Kasinath, Jamil R. Azzi, Jonathan S. Bromberg, Reza Abdi

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Figure 4

Ablation of CXCL12 of FRCs abrogates anti-CD40L mediated transplant tolerance.

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Ablation of CXCL12 of FRCs abrogates anti-CD40L mediated transplant tole...
(A) Flow cytometry analysis of T cell compartments in naive LNs (n = 3 mice/group). (B) Representative intravital images of CMFDA-labeled CD3+ T cells injected into naive LNs. Yellow and white arrows indicate the migration of transferred CMFDA+ CD3+ T cells from inside HEVs into the parenchyma. Representative trajectories of transferred CD3+ T cells (gray, cyan, and magenta lines) and quantitative analysis of cell migration from inside HEVs toward the parenchyma for 20 minutes (n = 3). Scale bars: 100 μm. (C) In vivo T cell migration assay in a skin transplantation model. Representative images and quantitative analysis of CMFDA-labeled CD3+ T cells in DLNs (n = 5). Scale bars: 100 μm. (D) Comparison of heart allograft survival among the recipients under CTLA4 Ig treatment (n = 7 mice/group). Graft survival data were combined from 2 independent experiments. (E) Representative images and comparison of CD3-, CD11c-, and collagen 1–stained heart allografts (n = 5 mice/group). Scale bars: 200 μm. (F) Flow cytometry analysis of DLNs (n = 5 mice/group). log-rank test for graft survival. Student’s t test for comparisons between 2 groups. Data are represented as means ± SEM. *P < 0.05; **P < 0.01; ***P < 0.001; ****P < 0.0001.