Neutrophil extracellular trap fragments stimulate innate immune responses that prevent lung transplant tolerance.

Abstract

Neutrophil extracellular traps (NETs) have been shown to worsen acute pulmonary injury including after lung transplantation. The breakdown of NETs by DNAse-1 can help restore lung function, but whether there is an impact on allograft tolerance remains less clear. Using intravital 2-photon microscopy, we analyzed the effects of DNAse-1 on NETs in mouse orthotopic lung allografts damaged by ischemia-reperfusion injury. Although DNAse-1 treatment rapidly degrades intragraft NETs, the consequential release of NET fragments induces prolonged interactions between infiltrating CD4+ T cells and donor-derived antigen presenting cells. DNAse-1 generated NET fragments also promote human alveolar macrophage inflammatory cytokine production and prime dendritic cells for alloantigen-specific CD4+ T cell proliferation through activating toll-like receptor (TLR) - Myeloid Differentiation Primary Response 88 (MyD88) signaling pathways. Furthermore, and in contrast to allograft recipients with a deficiency in NET generation due to a neutrophil-specific ablation of Protein Arginine Deiminase 4 (PAD4), DNAse-1 administration to wild-type recipients promotes the recognition of allo- and self-antigens and prevents immunosuppression-mediated lung allograft acceptance through a MyD88-dependent pathway. Taken together, these data show that the rapid catalytic release of NET fragments promotes innate immune responses that prevent lung transplant tolerance.

• Authors: Davide Scozzi, Xingan Wang, Fuyi Liao, Zhiyi Liu, Jihong Zhu, Katy Pugh, Mohsen Ibrahim, Hsi-Min Hsiao, Mark J Miller, Guo Yizhan, Thalachallour Mohanakumar, Alexander S Krupnick, Daniel Kreisel, Andrew E Gelman
• Journal: American journal of transplantation : official journal of the American Society of Transplantation and the American Society of Transplant Surgeons (Am J Transplant) Vol. 19 Issue 4 Pg. 1011-1023 (04 2019) ISSN: 1600-6143 [Electronic] United States
• PMID: 30378766 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)
• Copyright: © 2018 The American Society of Transplantation and the American Society of Transplant Surgeons.

Chemical References

• Inflammation Mediators
• Deoxyribonucleases

Topics

• Animals
• Cells, Cultured
• Dendritic Cells (immunology)
• Deoxyribonucleases (metabolism)
• Enzyme-Linked Immunosorbent Assay
• Extracellular Traps (immunology, metabolism)
• Humans
• Immunity, Innate (immunology)
• Inflammation Mediators (metabolism)
• Lung Transplantation
• Macrophages, Alveolar (cytology, immunology, metabolism)
• Mice
• Mice, Inbred BALB C
• Reperfusion Injury
• Transplantation Tolerance