Role of mononuclear phagocyte-epithelium crosstalk in alveolar repair
Final Report Abstract
The central aims of the Project were (1) to dissect the contribution of distinct subsets/differentiation stages of lung resident and newly recruited mononuclear phagocytes to the repair of alveolar surface structures following acute lung injury (ALI) and (2) to identify the signals by which mononuclear phagocytes induce such repair programs and the molecules that mediate mononuclear phagocyte-driven alveolar epithelial repair. We focused on Influenza A Virus (IAV)-induced acute lung injury/acute respiratory distress syndrome (ARDS) characterized by severe inflammation in the alveolar compartment of the lung, associated with apoptotic injury of the alveolar epithelium, resulting in loss of barrier function, edema formation and impaired gas exchange capacity with respiratory failure.!We identified a pool of local lung epithelial stem/progenitor cells (EpiSPC) which were found to be crucial for bronchoalveolar tissue regeneration after IV-induced injury. Their regenerative response depended on cooperation with mesenchymal cells of the stem cell niche and involved a βcatenin/FGF10/FGFR2b signaling axis, as well as epithelial GM-CSF. We demonstrated that IV infection of the stem cell niche critically impacts on the EpiSPC capacity to mediate coordinated tissue repair and established of murine three dimensional 3D in vitro lung organoid model based on FACS-sorting of self-renewing EpiSPC and co-culture with subsets of lung mesenchymal cells reproducing the 3D structure and cellular composition of the bronchoalveolar compartment. Regarding mononuclear phagocytes, we discovered that bone marrow derived macrophages recruited to the alveolar space during inflammation reveal high functional plasticity during IAV-induced ALI/ARDS. Distinct M1 and M2 polarized exudate macrophage (ExMa) immunophenotypes were defined and separated by a newly established FACS gating strategy, allowing analyses of their gene expression profiles and correlation with functional properties. Sequential flow cytometric quantification of ExMa revealed that in the early phase of IAV infection large numbers of M1 ExMa infiltrate the alveolar and, to lesser extent, the interstitial space of the lung. Later on, ExMa numbers decline but increasing proportions of M2 ExMa are present. Bone marrow chimeric mouse models and adoptive intratracheal ExMa transfer studies into ExMa recruitment-deficient CCR2-/- mice demonstrated that transferred M2 ExMa contribute to the regeneration of the alveolar epithelium and improve epithelial barrier function in IAV-induced ALI/ARDS. Transcriptomic profiling of lung recruited M1 versus M2 ExMa revealed highly distinct gene expression profiles, with M1 ExMa expressing pro-inflammatory/pro-apoptotic and host defense-associated genes, whereas M2 ExMa upregulate anti-inflammatory/anti-apoptotic genes and a high number of epithelial growth factors. The most highly upregulated gene in M2 versus M1 ExMa was found to be Placenta-expressed transcript 1 (Plet1), a growth factor previously associated with development of epithelial layers, epithelial cell proliferation and formation of epithelial tight junctions. Together, these data indicate that M1 and M2 ExMa are functionally distinct phenotypes evolving during IAV infection, and that M2 programming of ExMa in vivo is protective with respect to alveolar barrier function due to expression of distinct growth factors acting on AEC and EpiSPC. Therefore, therapeutic intervention by either macrophage reprogramming strategies or by alveolar delivery of in vitro M2 programmed/preconditioned macrophages or of M2 macrophage derived growth factors such as Plet1 might be useful strategies to improve epithelium regeneration and outcome of ALI/ARDS in humans.
Publications
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Macrophage tumor necrosis factor-alpha induces epithelial expression of granulocyte macrophage- colony stimulating factor: impact on alveolar epithelial repair. Am J Respir Crit Care Med. 180:521-32, 2009
Cakarova L, Marsh, Wilhelm J, Mayer K, Grimminger F, Seeger W, Lohmeyer J, Herold S
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Surface expression of CD74 by type II alveolar epithelial cells: a potential mechanism for MIF-induced epithelial repair. Am J Physiol Lung Cell Mol Physiol. 296:L442- 452, 2009
Marsh L, Cakarova L, Kwapiszewska G, von Wulffen W, Herold S, Seeger W, Lohmeyer J
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Acute lung injury: How macrophages orchestrate resolution of inflammation and tissue repair. Front Immun. 2:65, 2011
Herold S, Mayer K, Lohmeyer J
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Exudate macrophages attenuate epithelial injury by the release of IL-1 receptor antagonist in gramnegative pneumonia. Am J Respir Crit Care Med. 183:1380-1390, 2011
Herold S, Shafiei Tabar T, Janßen H, Högner K, Cabanski M, Lewe-Schlosser P, Albrecht J, Driever F, Vadasz I, Seeger W, Steinmüller M, Lohmeyer J
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Alveolar epithelial cells orchestrate dendritic cell functions by release of GM-CSF in murine viral pneumonia. J Clin Invest. 122 (10):3652- 64, 2012
Unkel B, Hoegner K, Clausen BE, Lewe-Schlosser P, Bodner J, Gattenloehner S, Janßen H, Seeger W, Lohmeyer J, Herold S
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Streptococcus pneumoniae stimulates a STING- and IFN regulatory factor 3-dependent type I IFN production in macrophages, which regulates RANTES production in macrophages, cocultured alveolar epithelial cells, and mouse lungs. J Immunol.188:811-7, 2012
Koppe U, Högner K, Doehn JM, Müller HC, Witzenrath M, Gutbier B, Bauer S, Pribyl T, Hammerschmidt S, Lohmeyer J, Suttorp N, Herold S, Opitz B
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Macrophage-expressed IFN-β mediates apoptotic alveolar epithelial cell injury in severe influenza virus pneumonia. PLoS Pathog. 9(2):e1003188, 2013
Hoegner K, Wolff T, Pleschka S, Plog S, Gruber AD, Kalinke U, Walmrath HD, Bodner J, Gattenloehner S, Lewe-Schlosser P, Matrosovich M, Seeger W, Lohmeyer J, Herold S
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Inhaled GM-CSF as treatment of pneumonia-associated acute respiratory distress syndrome. Am J Respir Crit Care Med. 189(5):609-11, 2014
Herold S, Hoegner K, Vadász I, Gessler T, Wilhelm J, Mayer K, Morty RE, Walmrath HD, Seeger W, Lohmeyer J
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Evidence for the involvement of fibroblast growth factor 10 in lipofibroblast formation during embryonic lung development. Development. 142(23):4139-50, 2015
Al Alam D, El Agha E, Sakurai R, Kheirollahi V, Moiseenko A, Danopoulos S, Shrestha A, Schmoldt C, Quantius J, Herold S, Chao CM, Tiozzo C, De Langhe S, Plikus MV, Thornton M, Grubbs B, Minoo P, Rehan VK, Bellusci S
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Influenza virus infects epithelial stem/progenitor cells of the distal lung: impact on Fgfr2bdriven epithelial repair. Plos Pathog. 12(6):e1005544, 2016
Quantius J, Schmoldt C, Becker C, El Agha E, Wilhelm J, Morty RE, Vadasz I, Mayer K, Gattenloehner S, Fink L, Matrosovich M, Seeger W, Lohmeyer J, Bellusci S, Herold S
