Resolving mediators as novel therapies for idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a common disease with a bleak prognosis. Half of all patients diagnosed with IPF will die within 3-4 years. A scarring process occurs in the lungs, eventually replacing normal healthy lung tissue with dense scar tissue which prevents oxygen passing into the blood and the normal lung expansion associated with breathing. As a result patients develop intractable cough, become extremely breathless, and finally die as a result of lung failure. The cause of IPF is unknown and there are no useful treatments which impact on either the life expectancy or quality of life of these patients.

Considerable evidence implicates cells known as myofibroblasts in the generation of lung scar tissue in IPF. These cells are important in normal wound healing and provide structure to healthy organs including lungs, but in disease they behave abnormally. It is myofibroblasts that produce the dense tissue that fills the lungs. In addition they move to abnormal locations and multiply, leading to dense collections of myofibroblasts and scar tissue that distort normal lung structure. A group of chemicals called resolving mediators are produced by the body in response to tissue injury, and return inflamed tissues to the healthy state. Based on work in other organs, and our own preliminary data studying human lung myofibroblasts, we believe that these resolving mediators may also be very effective at inhibiting the pro-scarring function of lung myofibroblasts and hence reduce the lung scarring process in IPF. Using human lung myofibroblasts obtained from healthy subjects and patients with IPF, together with lung tissue, we will investigate how effective resolving mediators are at inhibiting the myofibroblast processes which lead to lung scarring.

General experimental protocols:

Primary human lung myofibroblasts (PHLMF) are grown from the lung parenchyma of patients with IPF and healthy non-fibrotic control tissue removed at lung resection. Human fibrocytes are grown from peripheral blood progenitors. Human lung explant tissue is obtained from healthy areas of lung removed during surgery for carcinoma.

AIM 1: To examine the effect of resolving mediators on PHLMF and fibroblast progenitors (peripheral blood fibrocytes) collected from patients with IPF compared to non fibrotic controls. We will investigate:
a) The effects of LXA4 and RvD2 on PHLMF biology (FBS and basic FGF-dependent wound healing, proliferation, TGFbeta-dependent collagen secretion, constitutive alphaSMA expression, contraction).
b) The effects of LXA4 and RvD2 on primary human fibrocyte biology using established techniques as described previously (wound healing, collagen secretion, differentiation, migration).
c) Whether resolving mediators inhibit epithelial-mesenchymal transition (EMT) using immunofluorescence staining on epithelial cell lines and primary epithelial cells.
d) Whether resolving mediators inhibit TGFbeta1-dependent cell signaling in both PHLMF and epithelial cells using various complementary techniques including Western blot and ELISA assays, immunohistochemistry, flow cytometry, and a luciferase reporter construct.
e) Assessment of resolving mediator receptor expression on PHLMF and fibrocytes using real-time RT-PCR, flow cytometry or Western blot.

AIM 2: To examine the effect of resolving mediators on TGFbeta-dependent responses in ex vivo human lung parenchyma (collagen secretion, alphaSMA expression) using immunohistochemistry and the measurement of soluble mediators in the culture supernatant.

AIM 3: To measure the concentrations of resolving mediators in the BAL of IPF patients compared to healthy age and smoking matched controls using commercial ELISAs and liquid chromatography-mass spectrometry

Who will benefit from this research?

There will be numerous beneficiaries of this research including both respiratory academia and the wider scientific community, the pharmaceutical industry, patients and healthcare systems including the NHS.

How will they benefit from this research?

For academic beneficiaries please see "Academic Beneficiaries" section.

The research proposed will be of great interest to the pharmaceutical industry, and the may uncover several molecules with the potential to be used as therapies, either in their native form or as analogues. We have worked closely with the pharmaceutical industry over the last decade, both with respect to understanding the basic science driving chronic lung disease, and with the development and phenotype-specific targeting of novel therapies. We are therefore well-placed to ensure that the outcomes of this research are considered for translation to therapy where appropriate.

Longer term, it is anticipated that the development of new therapies derived from this research will improve the quality of life and health for patients and reduce the financial burden of respiratory disease on healthcare systems including the NHS. A realistic time-frame for the development of novel treatments for early phase-clinical studies is 4 -6 years from the onset of the study - for example, some molecules under study are already synthesised and could be given by inhalation relatively quickly with appropriate attention to quality control during manufacture. For implementation into clinical practice, 10 years from the onset of the study is feasible.