Pulmonary fibrosis has emerged as the leading cause of death in patients with systemic sclerosis (SSc)/scleroderma, yet currently available therapies are only marginally effective. While recent work from several groups of investigators suggests a key role for lung macrophages in the development of pulmonary fibrosis in patients with SSc, this remains an area of controversy as the specific population(s) of lung macrophages that drive fibrosis and the molecular mechanisms by which they do so remain largely unknown. In advance of this proposal, we have developed novel tools to elucidate macrophage heterogeneity in the mouse and human lung including lineage tagging, flow cytometry and transcriptional profiling in order to examine the differential role of tissue-resident alveolar macrophages, as compared to the monocyte-derived alveolar macrophages recruited to the lung, in the pathogenesis of fibrosis. Using unbiased transcriptional analysis (RNAseq) of flow-sorted macrophage populations over the course of the development of experimental fibrosis, we identified genetic signatures of monocyte to alveolar macrophage differentiation and fibrosis. Moreover, we have developed a murine model, which lacks the pathogenic monocyte-derived macrophage and is thus unable to develop lung fibrosis. Specifically, mice with macrophage-specific deletion of caspase-8, a cysteine-aspartic acid protease originally identified as a key initiator of the apoptotic death receptor pathway and suppressor of necroptosis (CreLysMCasp8fl/fl or CreCD11cCasp8fl/fl), showed significantly attenuated fibrosis and an inability for recruited monocytes to differentiate into pro-fibrotic monocyte-derived Siglec Flow macrophages following intratracheal treatment with either bleomycin or an adenovirus encoding an active form of TGF-? as compared to Casp8fl/fl, CreLysM or CreCD11c mice. Thus, this model is an ideal to tool to understand the differentiation of monocytes into pro-fibrotic alveolar macrophages in response to lung injury. These model systems will allow us to apply the transcriptional data to the study of monocytes from patients with SSc differentiated into alveolar macrophages in the lungs of humanized mice and alveolar macrophages obtained from patients with SSc at the time of lung transplantation. Our studies will test the hypothesis that monocyte differentiation into pro-fibrotic Siglec Flow alveolar macrophages is essential for the development of lung fibrosis in both mice and humans in three interrelated specific aims.

Public Health Relevance

Tissue resident and monocyte-derived alveolar macrophages are present in lungs from patients with SSc; however, the role that these populations play in disease development is unknown. We now show that mice deficient in caspase-8 specifically in macrophages have markedly less lung fibrosis and reduced monocyte derived alveolar macrophages than their littermate controls. Thus, in this application, we suggest a new paradigm for fibrosis in which monocyte-derived alveolar macrophages are critical for development of lung fibrosis.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL134375-02
Application #
9412514
Study Section
Special Emphasis Panel (ZRG1)
Program Officer
Craig, Matt
Project Start
2017-02-01
Project End
2021-01-31
Budget Start
2018-02-01
Budget End
2019-01-31
Support Year
2
Fiscal Year
2018
Total Cost
Indirect Cost
Name
Northwestern University at Chicago
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
005436803
City
Chicago
State
IL
Country
United States
Zip Code
60611
Mehta, Manan M; Weinberg, Samuel E; Steinert, Elizabeth M et al. (2018) Hexokinase 2 is dispensable for T cell-dependent immunity. Cancer Metab 6:10
Chalmers, Samantha A; Wen, Jing; Doerner, Jessica et al. (2018) Highly selective inhibition of Bruton's tyrosine kinase attenuates skin and brain disease in murine lupus. Arthritis Res Ther 20:10
Mandelin 2nd, Arthur M; Homan, Philip J; Shaffer, Alexander M et al. (2018) Transcriptional Profiling of Synovial Macrophages Using Minimally Invasive Ultrasound-Guided Synovial Biopsies in Rheumatoid Arthritis. Arthritis Rheumatol 70:841-854
Donlin, Laura T; Rao, Deepak A; Wei, Kevin et al. (2018) Methods for high-dimensonal analysis of cells dissociated from cyropreserved synovial tissue. Arthritis Res Ther 20:139
Coates, Bria M; Staricha, Kelly L; Koch, Clarissa M et al. (2018) Inflammatory Monocytes Drive Influenza A Virus-Mediated Lung Injury in Juvenile Mice. J Immunol 200:2391-2404
Brazee, Patricia L; Soni, Pritin N; Tokhtaeva, Elmira et al. (2017) FXYD5 Is an Essential Mediator of the Inflammatory Response during Lung Injury. Front Immunol 8:623
Ross, E A; Naylor, A J; O'Neil, J D et al. (2017) Treatment of inflammatory arthritis via targeting of tristetraprolin, a master regulator of pro-inflammatory gene expression. Ann Rheum Dis 76:612-619
Misharin, Alexander V; Morales-Nebreda, Luisa; Reyfman, Paul A et al. (2017) Monocyte-derived alveolar macrophages drive lung fibrosis and persist in the lung over the life span. J Exp Med 214:2387-2404
MacLauchlan, Susan; Zuriaga, Maria A; Fuster, José J et al. (2017) Genetic deficiency of Wnt5a diminishes disease severity in a murine model of rheumatoid arthritis. Arthritis Res Ther 19:166
Zheng, Zhikun; Chiu, Stephen; Akbarpour, Mahzad et al. (2017) Donor pulmonary intravascular nonclassical monocytes recruit recipient neutrophils and mediate primary lung allograft dysfunction. Sci Transl Med 9:

Showing the most recent 10 out of 15 publications