High-dimensional analysis reveals a pathogenic role of inflammatory monocytes in experimental diffuse alveolar hemorrhage
Pui Y. Lee, … , Westley H. Reeves, Peter A. Nigrovic
Pui Y. Lee, … , Westley H. Reeves, Peter A. Nigrovic
Published August 8, 2019
Citation Information: JCI Insight. 2019;4(15):e129703. https://doi.org/10.1172/jci.insight.129703.
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Research Article Pulmonology

High-dimensional analysis reveals a pathogenic role of inflammatory monocytes in experimental diffuse alveolar hemorrhage

Abstract

Diffuse alveolar hemorrhage (DAH) is a life-threatening pulmonary complication associated with systemic lupus erythematosus, vasculitis, and stem cell transplant. Little is known about the pathophysiology of DAH, and no targeted therapy is currently available. Pristane treatment in mice induces systemic autoimmunity and lung hemorrhage that recapitulates hallmark pathologic features of human DAH. Using this experimental model, we performed high-dimensional analysis of lung immune cells in DAH by mass cytometry and single-cell RNA sequencing. We found a large influx of myeloid cells to the lungs in DAH and defined the gene expression profile of infiltrating monocytes. Bone marrow–derived inflammatory monocytes actively migrated to the lungs and homed adjacent to blood vessels. Using 3 models of monocyte deficiency and complementary transfer studies, we established a central role of inflammatory monocytes in the development of DAH. We further found that the myeloid transcription factor interferon regulatory factor 8 is essential to the development of both DAH and type I interferon–dependent autoimmunity. These findings collectively reveal monocytes as a potential treatment target in DAH.

Authors

Pui Y. Lee, Nathan Nelson-Maney, Yuelong Huang, Anaïs Levescot, Qiang Wang, Kevin Wei, Pierre Cunin, Yi Li, James A. Lederer, Haoyang Zhuang, Shuhong Han, Edy Y. Kim, Westley H. Reeves, Peter A. Nigrovic

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Figure 5

Irf8 is required for the development of pristane-induced autoimmunity.

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Irf8 is required for the development of pristane-induced autoimmunity. (...
(A) Flow cytometry analysis of peripheral blood monocytes and neutrophils in WT and Irf8–/– mice in response to pristane treatment (n = 4 per group). (B) Flow cytometry analysis of Sca-1 expression on B lymphocytes (B220+) in WT and Irf8–/– mice 2 weeks after pristane treatment (n = 4 per group). (C) Flow cytometry analysis and quantification of peritoneal exudate cells (n = 4 per group). Blue gate, Ly6Chi monocytes; green gate, Ly6Clo monocytes; red gate, Ly6C-intermediate Ly6G+ neutrophils. (D) Heatmap comparison of IFN-I–regulated gene expression. (E) GSEA of differentially regulated genes in WT and Irf8–/– mice 2 weeks after pristane treatment. Gene sets were filtered by nominal P < 0.0001 and FDR < 0.01 and ranked by normalized enrichment score. (F) Total serum IgG levels, (G) ANA levels by fluorescence microscopy, (H) anti-U1RNP levels by ELISA, and (I) immunofluorescence of glomerular IgG and C3 staining in WT and Irf8–/– mice (n = 8–10 per group) 6 months after pristane treatment. Scale bar: 100 μm. Data are representative of 2 independent experiments (A–C) or pooled from 2 independent experiments (F–I). Statistical analysis was performed using paired Student’s t test (A and B) and unpaired Student’s t test (C and F–I). *P < 0.05.