Dataset Information

The alveolar epithelium determines susceptibility to lung fibrosis in Hermansky-Pudlak syndrome.

ABSTRACT:

Rationale

Hermansky-Pudlak syndrome (HPS) is a family of recessive disorders of intracellular trafficking defects that are associated with highly penetrant pulmonary fibrosis. Naturally occurring HPS mice reliably model important features of the human disease, including constitutive alveolar macrophage activation and susceptibility to profibrotic stimuli.

Objectives

To decipher which cell lineage(s) in the alveolar compartment is the predominant driver of fibrotic susceptibility in HPS.

Methods

We used five different HPS and Chediak-Higashi mouse models to evaluate genotype-specific fibrotic susceptibility. To determine whether intrinsic defects in HPS alveolar macrophages cause fibrotic susceptibility, we generated bone marrow chimeras in HPS and wild-type mice. To directly test the contribution of the pulmonary epithelium, we developed a transgenic model with epithelial-specific correction of the HPS2 defect in an HPS mouse model.

Measurements and main results

Bone marrow transplantation experiments demonstrated that both constitutive alveolar macrophage activation and increased susceptibility to bleomycin-induced fibrosis were conferred by the genotype of the lung epithelium, rather than that of the bone marrow-derived, cellular compartment. Furthermore, transgenic epithelial-specific correction of the HPS defect significantly attenuated bleomycin-induced alveolar epithelial apoptosis, fibrotic susceptibility, and macrophage activation. Type II cell apoptosis was genotype specific, caspase dependent, and correlated with the degree of fibrotic susceptibility.

Conclusions

We conclude that pulmonary fibrosis in naturally occurring HPS mice is driven by intracellular trafficking defects that lower the threshold for pulmonary epithelial apoptosis. Our findings demonstrate a pivotal role for the alveolar epithelium in the maintenance of alveolar homeostasis and regulation of alveolar macrophage activation.

SUBMITTER: Young LR

PROVIDER: S-EPMC3530211 | biostudies-literature | 2012 Nov

REPOSITORIES: biostudies-literature

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Publications

The alveolar epithelium determines susceptibility to lung fibrosis in Hermansky-Pudlak syndrome.

Young Lisa R LR Gulleman Peter M PM Bridges James P JP Weaver Timothy E TE Deutsch Gail H GH Blackwell Timothy S TS McCormack Francis X FX

American journal of respiratory and critical care medicine 20121004 10

<h4>Rationale</h4>Hermansky-Pudlak syndrome (HPS) is a family of recessive disorders of intracellular trafficking defects that are associated with highly penetrant pulmonary fibrosis. Naturally occurring HPS mice reliably model important features of the human disease, including constitutive alveolar macrophage activation and susceptibility to profibrotic stimuli.<h4>Objectives</h4>To decipher which cell lineage(s) in the alveolar compartment is the predominant driver of fibrotic susceptibility i ...[more]

PMID: 23043085

Similar Datasets

Project description:RationaleIndividuals with Hermansky-Pudlak syndrome type 1 (HPS-1), an autosomal recessive disorder characterized by defective biogenesis of lysosome-related organelles, develop an accelerated form of progressive fibrotic lung disease. The etiology of pulmonary fibrosis associated with HPS-1 is unknown.ObjectivesTo investigate the potential pathogenesis of pulmonary fibrosis in HPS-1, lung cells and proteins from individuals with HPS-1 were studied.MethodsForty-one subjects with HPS-1 with and without pulmonary fibrosis were evaluated with pulmonary function tests, high-resolution computed tomography scan, and bronchoscopy. Bronchoalveolar lavage cells and analytes were analyzed.Measurements and main resultsConcentrations of total bronchoalveolar lavage cells and alveolar macrophages were significantly higher in epithelial lining fluid from subjects with HPS-1 with and without pulmonary fibrosis compared with healthy research volunteers. Concentrations of cytokines and chemokines (i.e., monocyte chemoattractant protein-1, macrophage inflammatory protein-1alpha, and granulocyte-macrophage colony-stimulating factor) in alveolar epithelial lining fluid were significantly higher in subjects with HPS-1 with and without pulmonary fibrosis compared with healthy research volunteers (P < 0.001). In vitro, HPS-1 pulmonary fibrosis alveolar macrophages, which did not express HPS1 mRNA, secreted significantly higher concentrations of monocyte chemoattractant protein-1, macrophage inflammatory protein-1alpha, and regulated upon activation, normal T cell expressed and secreted (RANTES) protein compared with normal cells (P = 0.001, P = 0.014, and P = 0.011, respectively). Pirfenidone suppressed HPS-1 alveolar macrophage cytokine and chemokine secretion in vitro in a dose-dependent manner.ConclusionsIn HPS-1, alveolar inflammation predominantly involves macrophages and is associated with high lung concentrations of cytokines and chemokines. HPS-1 alveolar macrophages provide a model system in which to study the pathogenesis and treatment of HPS pulmonary fibrosis.

Dataset Information

The alveolar epithelium determines susceptibility to lung fibrosis in Hermansky-Pudlak syndrome.

Rationale

Objectives

Methods

Measurements and main results

Conclusions

Publications

The alveolar epithelium determines susceptibility to lung fibrosis in Hermansky-Pudlak syndrome.

Similar Datasets

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