Dysregulated Treg repair responses lead to chronic rejection after heart transplantation
Jordan J.P. Warunek, … , Khodor I. Abou-Daya, Hēth R. Turnquist
Jordan J.P. Warunek, … , Khodor I. Abou-Daya, Hēth R. Turnquist
Published December 2, 2024
Citation Information: J Clin Invest. 2024;134(23):e173593. https://doi.org/10.1172/JCI173593.
View: Text | PDF
Research Article Immunology

Dysregulated Treg repair responses lead to chronic rejection after heart transplantation

Abstract

Chronic rejection (CR) after organ transplantation is alloimmune injury manifested by graft vascular remodeling and fibrosis that is resistant to immunosuppression. Single-cell RNA-Seq analysis of MHC class II–mismatched (MHCII-mismatched) heart transplants developing chronic rejection identified graft IL-33 as a stimulator of tissue repair pathways in infiltrating macrophages and Tregs. Using IL-33–deficient donor mice, we show that graft fibroblast–derived IL-33 potently induced amphiregulin (Areg) expression by recipient Tregs. The assessment of clinical samples also confirmed increased expression of Areg by intragraft Tregs also during rejection. Areg is an EGF secreted by multiple immune cells to shape immunomodulation and tissue repair. In particular, Areg is proposed to play a major role in Treg-mediated muscle, epithelium, and nerve repair. Assessment of recipient mice with Treg-specific deletion of Areg surprisingly uncovered that Treg secretion of Areg contributed to CR. Specifically, heart transplants from recipients with Areg-deficient Tregs showed less fibrosis, vasculopathy, and vessel-associated fibrotic niches populated by recipient T cells. Mechanistically, we show that Treg-secreted Areg functioned to increase fibroblast proliferation. In total, these studies identify how a dysregulated repair response involving interactions between IL-33+ fibroblasts in the allograft and recipient Tregs contributed to the progression of CR.

Authors

Jordan J.P. Warunek, Lu Fan, Xue Zhang, Sihua Wang, Steven M. Sanders, Tengfang Li, Lisa R. Mathews, Gaelen K. Dwyer, Michelle A. Wood-Trageser, Stephanie Traczek, Andrew Lesniak, Kassandra Baron, Hailey Spencer, Johnny Bou Saba, Emmanuel León Colón, Tracy Tabib, Robert Lafyatis, Mark A. Ross, Anthony J. Demetris, Simon C. Watkins, Steven A. Webber, Khodor I. Abou-Daya, Hēth R. Turnquist

×

Figure 6

Augmented Areg in Treg is observed during clinical graft rejection and chronic allograft vasculopathy.

Options: View larger image (or click on image) Download as PowerPoint
Augmented Areg in Treg is observed during clinical graft rejection and c...
(A–C) snRNA-Seq of heart samples from patients with severe CAV versus controls (GSE203548). (A) UMAP projection of all samples with T cell classifications labeled and highlighted by color. Heatmap depicts the expression of lineage markers used to assign neighborhoods. (B) Nuclei from the CAV samples or control samples were separated in the UMAP projection, respectively. (C) Counts of the T cell types in CAV and control samples and mean expression of Areg in the T cell types. (D and E) Assessment of EMBs for Areg (red), Foxp3 (green), and DAPI (blue). (D) Representative immunofluorescence images of an EMB displaying QuPath trainable cell detection to identify Tregs and Areg+ Tregs. White arrows indicate Areg staining. Scale bars: 50 μm. Insets present higher magnification of the indicated areas (original magnification, ~×2,000). (E) Number of Tregs and their level of Areg expression grouped by EMBs with minimal, mild, and moderate/severe allograft inflammation (n = 3–4 minimal, 7 = mild, 8 = moderate/severe). Large symbols depict the mean cell counts for individual patients, and color- and symbol-matched small symbols provide the cell values for each sample section. The thick bar and error bars represent the mean ± SD calculated from the individual patient means. *P ≤ 0.05 and **P ≤ 0.01, by 1-way ANOVA with Tukey’s multiple-comparison test.