Title: Surfactant protein-D modulation of pulmonary macrophage phenotype is controlled by S-nitrosylation.

Authors: Guo, Chang-Jiang; Atochina-Vasserman, Elena N; Abramova, Elena; Smith, Ley Cody; Beers, Michael F; Gow, Andrew J

Published In Am J Physiol Lung Cell Mol Physiol, (2019 11 01)

Abstract: Surfactant protein-D (SP-D) is a regulator of pulmonary innate immunity whose oligomeric state can be altered through S-nitrosylation to regulate its signaling function in macrophages. Here, we examined how nitrosylation of SP-D alters the phenotypic response of macrophages to stimuli both in vivo and in vitro. Bronchoalveolar lavage (BAL) from C57BL6/J and SP-D-overexpressing (SP-D OE) mice was incubated with RAW264.7 cells ± LPS. LPS induces the expression of the inflammatory genes Il1b and Nos2, which is reduced 10-fold by SP-D OE-BAL. S-nitrosylation of the SP-D OE-BAL (SNO-SP-D OE-BAL) abrogated this inhibition. SNO-SP-D OE-BAL alone induced Il1b and Nos2 expression. PCR array analysis of macrophages incubated with SP-D OE-BAL (±LPS) shows increased expression of repair genes, Ccl20, Cxcl1, and Vcam1, that was accentuated by LPS. LPS increases inflammatory gene expression, Il1a, Nos2, Tnf, and Ptgs2, which was accentuated by SNO-SP-D OE-BAL but inhibited by SP-D OE-BAL. The transcription factor NF-κB was identified as a target for SNO-SP-D by IPA, which was confirmed by Trans-AM ELISA in vitro. In vivo, SP-D overexpression increases the burden of infection in a Pneumocystis model while increasing cellular recruitment. Expression of iNOS and the production of NO metabolites were significantly reduced in SP-D OE mice relative to C57BL6/J. Inflammatory gene expression was increased in infected C57BL6/J mice but decreased in SP-D OE. SP-D oligomeric structure was disrupted in C57BL6/J infected mice but unaltered within SP-D OE. Thus SP-D modulates macrophage phenotype and the balance of multimeric to trimeric SP-D is critical to this regulation.

PubMed ID: 31411060

MeSH Terms: Animals; Bronchoalveolar Lavage Fluid/chemistry; Bronchoalveolar Lavage Fluid/immunology; Chemokine CCL20/genetics; Chemokine CCL20/immunology; Chemokine CXCL1/genetics; Chemokine CXCL1/immunology; Cyclooxygenase 2/genetics; Cyclooxygenase 2/immunology; Female; Immunity, Innate; Interleukin-1beta/genetics; Interleukin-1beta/immunology; Lipopolysaccharides/pharmacology; Lung/immunology; Lung/metabolism; Lung/microbiology; Macrophages, Alveolar/drug effects; Macrophages, Alveolar/immunology*; Macrophages, Alveolar/microbiology; Male; Mice; Mice, Inbred C57BL; NF-kappa B/genetics; NF-kappa B/immunology; Nitric Oxide Synthase Type II/genetics; Nitric Oxide Synthase Type II/immunology; Nitroso Compounds/immunology; Nitroso Compounds/metabolism*; Phenotype; Pneumocystis Infections/genetics*; Pneumocystis Infections/immunology; Pneumocystis Infections/metabolism; Pneumocystis Infections/microbiology; Pneumocystis/growth & development; Pneumocystis/pathogenicity; Protein Processing, Post-Translational*; Pulmonary Surfactant-Associated Protein D/genetics; Pulmonary Surfactant-Associated Protein D/immunology; Pulmonary Surfactant-Associated Protein D/metabolism*; RAW 264.7 Cells; Tumor Necrosis Factor-alpha/genetics; Tumor Necrosis Factor-alpha/immunology; Vascular Cell Adhesion Molecule-1/genetics; Vascular Cell Adhesion Molecule-1/immunology