Modulation of Steroid Immunosuppression by Alveolar Efferocytosis

Study Overview
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Brief Summary
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The long-term goals of this study are (a) to understand the biological underpinnings for the increased incidence of community-acquired pneumonia in patients with chronic obstructive pulmonary disease (COPD) who are treated with inhaled corticosteroids; and (b) to develop novel therapies to treated this problem using over-expression of micro-RNAs (miRNAs).

Detailed Description
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Treating chronic obstructive pulmonary disease (COPD) patients with inhaled glucocorticosteroids has been convincingly shown to increase their risk of pneumonia, but the responsible mechanisms are undefined. Work from this laboratory suggests a possible mechanism, related to the increased numbers of cells dying by apoptosis in the lungs in COPD, especially in emphysema. Uptake of apoptotic cells (efferocytosis) suppresses the ability of alveolar macrophages (AM) to fight infections. By markedly increasing AM efferocytosis, glucocorticoids plus apoptotic cells cause greater immune defects than either stimulus alone. These defects include reductions in killing of Streptococcus pneumoniae by human AM and murine AM in vitro, and in clearance of viable pneumococci from lungs of mice. This effect is called glucocorticoid augmented efferocytosis (GCAE). MicroRNAs (miRNAs) are 19-25 nucleotide-long non-coding RNAs that coordinately target large numbers of genes and reduce their protein products. Preliminary data imply that defective AM function is caused by down-regulation of specific miRNAs by GCAE (but not by apoptotic cells alone or glucocorticosteroids alone). The long-term goal of this project is to develop novel inhalational treatments based on transient over-expression of these specifically decreased miRNAs, to reverse defective AM immune function when COPD patients taking inhaled glucocorticoids present with community-acquired pneumonia. This project will use both ex vivo investigation of AM from human volunteers (never-smokers; smokers with normal spirometry; and COPD subjects who are current or former smokers), and an established murine model of pneumococcal pneumonia. Its immediate goals are to: (a) confirm that GCAE increases pneumococcal pneumonia risk and severity, and in the process, validate a murine model for testing strategies to reverse those defects; (b) define GCAE-induced AM defects functionally and by whole-transcriptome analysis, identifying genes and miRNAs uniquely regulated by the GCAE x pneumococcus interaction; (c) validate and optimize miRNA-over-expression to reverse the adverse effects of GCAE on AM defensive functions. Successful completion of this project could lead to more precisely personalized therapies and better outcomes in COPD, currently the third leading cause of death in the USA

Official Title
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Modulation of Steroid Immunosuppression by Alveolar Efferocytosis

Conditions
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Pulmonary Disease, Chronic Obstructive, Pneumonia, Bacterial

Intervention / Treatment
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* Procedure: Bronchoscopy with bilateral bronchoalveolar lavages


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Inclusion Criteria for healthy subjects without COPD: Age 18-80 years, inclusive Males or females Never smoker (< 100 cigarettes in lifetime) OR Current smoker (>10 pack-years) with normal spirometry Able to perform satisfactory spirometry Abe to give informed consent Able to complete questionnaires Inclusion Criteria for COPD subjects: Age 18-80 years, inclusive Males or females Current smoker (>10 pack-years) & (≥1/2 pack/day) OR Former smoker (>10 pack-years) & (>6 months of non-smoking) Diagnosis of COPD by ATS/ERS1 criteria Able to perform satisfactory spirometry Able to give informed consent Able to complete questionnaires 1 ATS/ERS, American Thoracic Society/European Respiratory Society. Exclusion Criteria: Exclusion Criteria for healthy subjects without COPD: Unstable cardiovascular disease, including uncontrolled hypertension, CHF, angina Significant renal (creatinine >2.5) or hepatic dysfunction (Childs B or C) Mental incompetence/active psychiatric illness Prednisone or other immunosuppressive medications Participation in another interventional experimental protocol within 6 weeks Pregnancy Use of antibiotics for any reason within 42 days Judged to be unsuitable for bronchoscopy by PI Resting SaO2<93% FEV1 < 70% predicted Respiratory infections within 42 days regardless of antibiotic use Diagnosed COPD or Asthma Use of inhaled corticosteroids Active pulmonary tuberculosis or other serious chronic respiratory infection Diffuse panbronchiolitis or Cystic fibrosis Clinically significant bronchiectasis History of thoracic radiation therapy for any cause Other inflammatory or fibrotic lung disease Exclusion Criteria for COPD subjects: Unstable cardiovascular disease, including uncontrolled hypertension, CHF, angina Significant renal (creatinine >2.5) or hepatic dysfunction (Childs B or C) Mental incompetence/active psychiatric illness Prednisone or other immunosuppressive medications Participation in another interventional experimental protocol within 6 weeks Pregnancy Use of antibiotics for any reason within 42 days Judged to be unsuitable for bronchoscopy by PI Resting daytime SaO2<90% while breathing room air FEV1 < 50% predicted Respiratory infections within 42 days regardless of antibiotic use Use of inhaled corticosteroids Active pulmonary tuberculosis or other serious chronic respiratory infection Diffuse panbronchiolitis or Cystic fibrosis Clinically significant bronchiectasis History of thoracic radiation therapy for any cause Other inflammatory or fibrotic lung disease

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: This study will analyze both healthy subjects (never-smokers and current- or ex-smokers) in one arm, and also subjects with COPD (current- or ex-smokers).
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Healthy Participants<br>Procedure/Surgery: Bronchoscopy with bilateral bronchoalveolar lavages. Drugs: No test substances, only moderate conscious sedation using standard medications. Devices: No test devices. | Procedure: Bronchoscopy with bilateral bronchoalveolar lavages<br>* Bronchoscopy with bilateral bronchoalveolar lavages<br>|
| Experimental: COPD participants<br>Procedure/Surgery: Bronchoscopy with bilateral bronchoalveolar lavages. Drugs: No test substances, only moderate conscious sedation using standard medications. Devices: No test devices. | Procedure: Bronchoscopy with bilateral bronchoalveolar lavages<br>* Bronchoscopy with bilateral bronchoalveolar lavages<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Bactericidal activity of human alveolar macrophage against S. pneumoniae in vitro | Alveolar macrophages from volunteers will be be assayed for their ability to kill pneumococci in vitro following treatment with glucocorticoids, apoptotic cells or both. Participation of the subjects ends after bronchoscopy, and no clinical outcomes will be measured. | 24 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Mechanisms of human alveolar macrophage killing of S. pneumoniae in vitro | These same macrophages will also be assayed for production of mRNA and regulatory microRNAs (by RNA sequencing and quantitative real-time PCR and for cytokine and chemokine production. | 24 hours | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Apoptosis, Bronchoscopy, Human, Mice, inbred strains, Macrophages, Alveolar, MicroRNAs, Streptococcus pneumoniae, Fluticasone