Dataset Information

The role of surfactant protein A in bleomycin-induced acute lung injury.

ABSTRACT:

Rationale

Surfactant protein A (SP-A) is a collectin family member that has multiple immunomodulatory roles in lung host defense. SP-A levels are altered in the bronchoalveolar lavage (BAL) fluid and serum of patients with acute lung injury and acute respiratory distress syndrome, suggesting the importance of SP-A in the pathogenesis of acute lung injury.

Objectives

Investigate the role of SP-A in the murine model of noninfectious lung injury induced by bleomycin treatment.

Methods

Wild-type (WT) or SP-A deficient (SP-A(-/-)) mice were challenged with bleomycin, and various indices of lung injury were analyzed.

Measurements and main results

On challenge with bleomycin, SP-A(-/-) mice had a decreased survival rate as compared with WT mice. SP-A(-/-) mice had a higher degree of neutrophil-dominant cell recruitment and the expression of the inflammatory cytokines in BAL fluid than did WT mice. In addition, SP-A(-/-) mice had increased lung edema as assessed by the increased levels of intravenously injected Evans blue dye leaking into the lungs. Terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling and active caspase-3 staining suggested the increased apoptosis in the lung sections from SP-A(-/-) mice challenged with bleomycin. SP-A also specifically reduced bleomycin-induced apoptosis in mouse lung epithelial 12 cells in vitro. Moreover, intratracheal administration of exogenous SP-A rescued the phenotype of SP-A(-/-) mice in vivo.

Conclusions

These data suggest that SP-A plays important roles in modulating inflammation, apoptosis, and epithelial integrity in the lung in response to acute noninfectious challenges.

SUBMITTER: Goto H

PROVIDER: S-EPMC2894409 | biostudies-literature | 2010 Jun

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

The role of surfactant protein A in bleomycin-induced acute lung injury.

Goto Hisatsugu H Ledford Julie G JG Mukherjee Sambuddho S Noble Paul W PW Williams Kristi L KL Wright Jo Rae JR

American journal of respiratory and critical care medicine 20100218 12

<h4>Rationale</h4>Surfactant protein A (SP-A) is a collectin family member that has multiple immunomodulatory roles in lung host defense. SP-A levels are altered in the bronchoalveolar lavage (BAL) fluid and serum of patients with acute lung injury and acute respiratory distress syndrome, suggesting the importance of SP-A in the pathogenesis of acute lung injury.<h4>Objectives</h4>Investigate the role of SP-A in the murine model of noninfectious lung injury induced by bleomycin treatment.<h4>Met ...[more]

PMID: 20167853

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Project description:Acute inflammatory exacerbations (AIEs) represent immune-driven deteriorations of many chronic lung conditions, including COPD, asthma, and pulmonary fibrosis (PF). The first line of therapy is represented by broad-spectrum immunomodulation. Among the several inflammatory populations mobilizing during AIEs, eosinophils have been identified as promising indicators of an active inflammatory exacerbation. To better study the eosinophil-parenchymal crosstalk during AIE-PF, this work leverages a clinically relevant model of inflammatory exacerbations triggered by inducible expression of a mutation in the alveolar epithelial type 2 cell Surfactant Protein-C gene [SP-CI73T]. Unbiased single-cell sequencing analysis of controls and SP-CI73T mutants at a time coordinated with peak eosinophilia (14 days) defined heightened inflammatory activation, chemotaxis, and survival signaling (IL-6, IL-4/13, STAT3, Glucocorticoid Receptor, mTOR, and MYC) in eosinophils. To study the impact of eosinophils in inflammatory exacerbations, the SP-CI73T line was crossed with eosinophil lineage deficient mice (GATA1Δdbl) to produce the SP-CI73TGATA1KO line. Time course analysis (7-42 days) demonstrated improved lung histology, survival, and reduced inflammation in SP-CI73TGATA1KO cohorts. Spectral flow cytometry of tissue digests confirmed eosinophil depletion in GATA1KO mice and the absence of a compensatory shift in neutrophils and immature monocyte recruitment. Eosinophil deletion resulted in progressive monocyte-derived macrophage accumulation (14 days post-injury), combined with declines in CD3+CD4+ lymphocyte and B220+ B cell abundance. Histochemical analysis revealed atypical inflammatory cell activation in SP-CI73TGATA1KO mice, with reduced numbers of Arg-1+ and iNOS+ cells, but increases in tgfb1 mRNA expression in bronchoalveolar lavage cells and tissue. Dexamethasone treatment (1 mg/kg daily, i.p.) was utilized to investigate corticosteroid efficacy in highly eosinophilic exacerbations induced by mutant SP-CI73T. Dexamethasone successfully reduced total and eosinophil (CD11b+SigF+CD11c-) counts at 14 days and was linked to reduced evidence of structural damage and perivascular infiltrate. Together, these results illustrate the deleterious role of eosinophils in inflammatory events preceding lung fibrosis and demonstrate the efficacy of corticosteroid treatment in highly eosinophilic exacerbations induced by mutant SP-CI73T.

Project description:Acute inflammatory exacerbations (AIEs) represent immune-driven deteriorations of many chronic lung conditions, including COPD, asthma, and pulmonary fibrosis (PF). The first line of therapy is represented by broad-spectrum immunomodulation. Among the several inflammatory populations mobilizing during AIEs, eosinophils have been identified as promising indicators of an active inflammatory exacerbation. To better study the eosinophil-parenchymal crosstalk during AIE-PF, this work leverages a clinically relevant model of inflammatory exacerbations triggered by mutation in the alveolar epithelial type 2 cell Surfactant Protein-C gene [SP-CI73T]. Unbiased single-cell sequencing analysis of controls and SP-CI73T mutants at a time coordinated with peak eosinophilia (14 d) defined heightened inflammatory activation, chemotaxis, and survival signaling (IL-6, IL-4/13, STAT3, Glucocorticoid Receptor, mTOR, and MYC) in eosinophils. To study the impact of eosinophils in inflammatory exacerbations, the SP-CI73T line was crossed with eosinophil lineage deficient mice (GATA1Δdbl, SP-CI73TGATA1KO). Time course analysis (7-42 d) demonstrated improved lung histology, survival, and reduced inflammation in SP-CI73TGATA1KO cohorts. Spectral flow cytometry of tissue digests confirmed eosinophil depletion in GATA1KO mice and the absence of a compensatory shift in neutrophils and immature monocyte recruitment. Eosinophil deletion was seen to boost accumulation of total monocyte-derived macrophages, 14 d post-injury, while declines in CD3+CD4+ lymphocyte abundance observed during SP-CI73T-induced injury were limited in SP-CI73TGATA1KO mice. Histochemical analysis 14 d post-injury revealed atypical inflammatory cell activation in SP-CI73TGATA1KO mice, with reduced numbers of Arg-1+ and iNOS+ cells, but increases in mcp1 and tgfb1 mRNA expression in BAL cells and tissue. To study corticosteroid efficacy in highly eosinophilic exacerbations, SP-CI73T mice received dexamethasone (1 mg/kg daily, i.p) starting 5 d post-induction. Dexamethasone successfully reduced total and eosinophil (CD11b+SigF+CD11c-) counts at 14 d and was linked to reduced evidence of structural damage and perivascular infiltrate. Together, these results illustrate the deleterious role of eosinophils in inflammatory events preceding lung fibrosis and demonstrate the efficacy of corticosteroid treatment in highly eosinophilic exacerbations induced by mutant SP-CI73T.

Dataset Information

The role of surfactant protein A in bleomycin-induced acute lung injury.

Rationale

Objectives

Methods

Measurements and main results

Conclusions

Publications

The role of surfactant protein A in bleomycin-induced acute lung injury.

Similar Datasets

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