Reprogramming alveolar macrophage responses to TGF-β reveals CCR2+ monocyte activity that promotes bronchiolitis obliterans syndrome
Zhiyi Liu, Fuyi Liao, Jihong Zhu, Dequan Zhou, Gyu Seong Heo, Hannah P. Leuhmann, Davide Scozzi, Antanisha Parks, Ramsey Hachem, Derek E. Byers, Laneshia K. Tague, Hrishikesh S. Kulkarni, Marlene Cano, Brian W. Wong, Wenjun Li, Howard J. Huang, Alexander S. Krupnick, Daniel Kreisel, Yongjian Liu, Andrew E. Gelman
Zhiyi Liu, Fuyi Liao, Jihong Zhu, Dequan Zhou, Gyu Seong Heo, Hannah P. Leuhmann, Davide Scozzi, Antanisha Parks, Ramsey Hachem, Derek E. Byers, Laneshia K. Tague, Hrishikesh S. Kulkarni, Marlene Cano, Brian W. Wong, Wenjun Li, Howard J. Huang, Alexander S. Krupnick, Daniel Kreisel, Yongjian Liu, Andrew E. Gelman
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Research Article Immunology Inflammation

Reprogramming alveolar macrophage responses to TGF-β reveals CCR2+ monocyte activity that promotes bronchiolitis obliterans syndrome

Abstract

Bronchiolitis obliterans syndrome (BOS) is a major impediment to lung transplant survival and is generally resistant to medical therapy. Extracorporeal photophoresis (ECP) is an immunomodulatory therapy that shows promise in stabilizing BOS patients, but its mechanisms of action are unclear. In a mouse lung transplant model, we show that ECP blunts alloimmune responses and inhibits BOS through lowering airway TGF-β bioavailability without altering its expression. Surprisingly, ECP-treated leukocytes were primarily engulfed by alveolar macrophages (AMs), which were reprogrammed to become less responsive to TGF-β and reduce TGF-β bioavailability through secretion of the TGF-β antagonist decorin. In untreated recipients, high airway TGF-β activity stimulated AMs to express CCL2, leading to CCR2+ monocyte-driven BOS development. Moreover, we found TGF-β receptor 2–dependent differentiation of CCR2+ monocytes was required for the generation of monocyte-derived AMs, which in turn promoted BOS by expanding tissue-resident memory CD8+ T cells that inflicted airway injury through Blimp-1–mediated granzyme B expression. Thus, through studying the effects of ECP, we have identified an AM functional plasticity that controls a TGF-β–dependent network that couples CCR2+ monocyte recruitment and differentiation to alloimmunity and BOS.

Authors

Zhiyi Liu, Fuyi Liao, Jihong Zhu, Dequan Zhou, Gyu Seong Heo, Hannah P. Leuhmann, Davide Scozzi, Antanisha Parks, Ramsey Hachem, Derek E. Byers, Laneshia K. Tague, Hrishikesh S. Kulkarni, Marlene Cano, Brian W. Wong, Wenjun Li, Howard J. Huang, Alexander S. Krupnick, Daniel Kreisel, Yongjian Liu, Andrew E. Gelman

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Figure 8

Mo-AM generation promotes TRM cell activation and expansion.

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Mo-AM generation promotes TRM cell activation and expansion. (A) A repre...
(A) A representative FACS plot set from 4 transplants where MFI is shown for TR-AM and Mo-AM MHC I H-2Kq, CD80, CD86, and PD-L1 expression levels. FMO, fluorescence-minus-one control. (B and C) Representative FACS plots and histograms for n = 4/group for the expression of TRM cell markers with FMO (black lines). (D) FACS-sorted 3T-FVB TR-AMs, Mo-AMs, and B6 AMs were cultured with FACS-sorted 3T-FVB allograft PD-1+CD49a+CD8+ T cells with 10 μg/ml control rat Ig or PD-L1–neutralizing Abs and then assessed for IFN-γ production by ELISA 72 hours later. Data shown are representative results from 2 experiments. (E) FACS-sorted, CFSE-labeled 3T-FVB allograft PD-1+CD49a+CD8+ T cells (green) were intratracheally administered to FVB (allogeneic) or B6 (syngeneic) lung transplants of B6 recipients. Eighteen hours later, transplants were imaged by 2-photon intravital microscopy immediately following the administration of Siglec F Abs to identify AMs (red). Representative intravital image from 1 of 4 FVB-transplanted lung studies. Arrows denote long-lasting contacts between TRM cells and AMs. Right panel shows violin plot of individual AM-TRM cell contact times from pooled data from 4 FVB (allogeneic) or B6 (syngeneic) transplanted lungs. (F) 2T-FVB allografts of B6 Thy1.1+ recipients were FACS-sorted for PD-1+CD49a+ and PD-1–CD49a– CD8+ T cells and intratracheally delivered into B6 Thy1.2+ recipients of 2T-FVB allografts and euthanized 1 month later. Shown are representative FACS plot results of Thy1.1+ cell percentage of abundance and cell count for indicated tissues (n = 4 per adoptive transfer). (G) 2T-FVB allograft FACS-sorted Thy1.1 PD-1+CD49a+CD8+ T cells were intratracheally administered into tamoxifen-treated TGF-βR2fl/fl and TGF-βR2Δ/Δ recipients of 3T-FVB allografts 3 days after DOX ingestion. Seventy-two hours later, recipients were euthanized. Data shown are representative FACS plots from n = 4/group for allograft percentage of abundance and cell counts. Data are represented as mean ± SD. Two-sided Mann-Whitney U test (A and G); 1-way ANOVA with Dunnett’s multiple-comparison test (D). *P < 0.05; **P < 0.01; ***P < 0.001.