Our group is broadly interested in translational research of rare lung diseases, which allows us to approach disease pathogenesis from the vantage point of a known molecular defect. Our goal is to develop new biomarkers and therapies with the potential to favorably impact human health in a short time frame. Many of our laboratory directions have been inspired by patients we have met, which gives our work purpose and meaning, and motivates us to ask questions that matter.

The McCormack laboratory is interested in genetic interstitial lung diseases and pulmonary innate immunity. Current projects are focused on lymphangioleiomyomatosis (LAM), pulmonary alveolar microlithiasis (PAM) and the role of the alveolar epithelium in influenza, mycobacterial and bacterial infection. We use animal models to develop biomarkers and strategies for trials, and try to focus on experimental plans that have a human trial on the horizon.

As an example, we developed the PAM mouse model by deleting the phosphate transporter, Npt2b, from the alveolar epithelium, as mutations in that protein are known to cause the disease in humans. The animals develop diffuse pulmonary alveolar microliths, which produce hyperdense infiltrates on radiographs and C/T scans that are easily measured and quantified. The cytokine MCP-1 is elevated in the lungs of the PAM animals, and also appears in their serum. We also found that the very large alveolar protein, surfactant protein D (SP-D), was elevated in PAM mouse serum, suggestive of lung injury and barrier dysfunction. We contacted a dozen PAM patients around the world to obtain blood, and found that MCP-1 and SP-D are also elevated in the serum of patients, and are now developing them as promising biomarkers for disease progression and response to therapy. We found that stones isolated from the lungs of the PAM mice readily dissolve in calcium chelators such as EGTA and EDTA, suggesting therapeutic chelation lavage as a treatment approach; an idea we intend to test in monkeys and bring to the bedside if proven safe. We have also found that a low phosphate diet reduces the stone burden in the lung, suggesting that a simple dietary intervention (perhaps together with a phosphate binder) could be developed as a treatment. Our lab is actively trying to understand the mechanism of stone clearance due to phosphate restriction, focusing on the effect of phosphate hormone mediators such as VitD3 and FGF-23 on expression of alternative phosphate transporters in the alveolar epithelium. We intend to conduct a trial in PAM patients through the NIH Rare Lung Disease Consortium, a network of 55 rare lung disease clinics located around the world, with Cincinnati as the hub, with co-investigators Bruce Trapnell, MD, and Frank McCormack, MD. The RLDC conducted the MILES trial for LAM, which demonstrated that sirolimus is an effective treatment. On the basis of the MILES result, the FDA approved sirolimus for LAM in 2015, and over 40 percent of LAM patients in North America are now taking the drug.

Other past and present Cincinnati-based RLDC projects have included developing a pathologic classification system for the pediatric interstitial lung diseases, developing diagnostic tests for pulmonary alveolar proteinosis, developing CT scanning as a biomarker of progression for alpha-1 antitrypsin deficiency, developing a longitudinal registry for LAM (MIDAS), and conducting a MILES-like trial of sirolimus in asymptomatic patients with LAM who have normal lung function (the MILED trial). McCormack and Trapnell have also developed a collaborative UC/CCHMC program called the Translational Pulmonary Science Center, which organizes the resources necessary for translational research in pulmonary disease and operates a CCTST-funded bronchoscopy core for the collection of lung samples.

Key accomplishments of the lab

1. Solution of the crystal structure of SP-A (with Barbara Seaton)
2. Characterization of the structure and function relationship of surfactant proteins A (SP-A) and D (SP-D)
3. Development of serum SP-A and VEGF-D as biomarkers in interstitial lung disease
4. Discovery of direct antimicrobial properties of SP-A and SP-D
5. Elucidation of the role of the pulmonary epithelium in fibrogenesis (in Hermansky Pudlak mouse models)
6. Identification of KGF as a promising therapeutic strategy for therapy of bacterial and mycobacterial infections
7. Elucidation of the molecular pathogenesis of pulmonary alveolar microlithiasis
8. Development of biomarkers and therapeutic targets for pulmonary alveolar microlithiasis
9. Discovery that the proliferative tone of alveolar type II epithelial cells determines susceptibility to influenza pneumonia

Publications resulting from our research

Current trials

1. Multicenter Interventional LAM Early Disease Trial (MILED).   Randomized controlled trial of early low dose sirolimus vs. placebo in LAM patients with normal lung function 

2. Multicenter International Durability of Sirolimus Trial (MIDAS).  Observational registry study of patients with LAM

Completed trials

1. Multicenter International LAM Efficacy of Sirolimus Trial (MILES).    Randomized controlled trial of sirolimus vs. placebo in LAM patients with abnormal lung function

2. Trial of an aromatase inhibitor in LAM (TRAIL).    Randomized controlled trial of letrozole vs. placebo in post-menopausal patients with LAM

Major projects in the lab

  • Development of biomarkers and treatments for pulmonary alveolar microlithiasis

  • The role of the pulmonary epithelium in susceptibility to viral, bacterial and mycobacterial infection.

  • Pulmonary collectins in innate host defense.

  • Use of mouse models to understand disease pathogenesis of lymphangioleiomyomatosis and other rare lung diseases.

 

Potential projects for students and fellows:

Interests: Rare lung diseases; development of diagnostic, predictive and prognostic biomarkers; interrogating clinical samples to elucidate molecular pathophysiologies underlying pulmonary diseases; factors that alter influenza susceptibility; differential diagnosis of lung diseases.

Potential projects: Clinical samples from patients with rare lung diseases have been collected.  Investigator-initiated projects could be permitted with approval.

Research skills acquired: Clinical research design and implementation, laboratory methods, biostatistical analysis, molecular basis of disease.

Training required or time delay: Dependent upon project.  For biomarker studies, sample procurement must be approved, fellow may need IRB training and approval.