Casein Kinase 1δ/ε Inhibitor, PF670462 Attenuates the Fibrogenic Effects of Transforming Growth Factor-β in Pulmonary Fibrosis.

Christine R Keenan,Glen P Westall,Trudi Harris,Danica Prodanovic,Meina Li,Alastair G Stewart,Bryan Gao,Jade Jaffar,Michael J Schuliga,Qianyu Chen,Yuxiu Xia,Shenna Y Langenbach,Fernando Jativa,Peter V S Lee,Asres Berhan,Yan Tu

doi:10.3389/fphar.2018.00738

Abstract

Transforming growth factor-beta (TGF-β) is a major mediator of fibrotic diseases, including idiopathic pulmonary fibrosis (IPF). However, therapeutic global inhibition of TGF-β is limited by unwanted immunosuppression and mitral valve defects. We performed an extensive literature search to uncover a little-known connection between TGF-β signaling and casein kinase (CK) activity. We have examined the abundance of CK1 delta and epsilon (CK1δ/ε) in lung tissue from IPF patients and non-diseased controls, and investigated whether inhibition of CK1δ/ε with PF670462 inhibits pulmonary fibrosis. CK1δ/ε levels in lung tissue from IPF patients and non-diseased controls were assessed by immunohistochemistry. Anti-fibrotic effects of the CK1δ/ε inhibitor PF670462 were assessed in pre-clinical models, including acute and chronic bleomycin mouse models and in vitro experiments on spheroids made from primary human lung fibroblast cells from IPF and control donors, and human A549 alveolar-like adenocarcinoma-derived epithelial cells. Increased expression of CK1δ and ε in IPF lungs compared to non-diseased controls was accompanied by increased levels of the product, phospho-period 2. In vitro, PF670462 prevented TGF-β-induced epithelial-mesenchymal transition. The stiffness of IPF-derived spheroids was reduced by PF670462 and TGF-β-induced fibrogenic gene expression was inhibited. The CK1δ/ε inhibitor PF670462 administered systemically or locally by inhalation prevented both acute and chronic bleomycin-induced pulmonary fibrosis in mice. PF670462 administered in a ‘therapeutic’ regimen (day 7 onward) prevented bleomycin-induced lung collagen accumulation. Elevated expression and activity of CK1 δ and ε in IPF and anti-fibrogenic effects of the dual CK1δ/ε inhibitor, PF670462, support CK1δ/ε as novel therapeutic targets for IPF.

Highlights

Fibrosis, a common feature of most chronic diseases, contributes to up to 45% of deaths in the industrialized world (Friedman et al, 2013)
Primary human parenchymal fibroblast cells were cultured from parenchyma of lung resection specimens from non-transplanted lungs of donors without chronic respiratory disease and those of idiopathic pulmonary fibrosis (IPF) patients diagnosed by multidisciplinary review (HREC #336/13; Alfred Hospital, Melbourne VIC, Australia), as previously described (Schuliga et al, 2009, 2017)
The distribution and level of immunoreactive CK1δ and CK1ε are altered in IPF (Figure 1), with each showing a striking increase in level at the cellular level

Summary

Introduction

A common feature of most chronic diseases, contributes to up to 45% of deaths in the industrialized world (Friedman et al, 2013). Idiopathic pulmonary fibrosis (IPF) is an irreversible, progressive and usually fatal lung disease characterized by fibrosis of the lung parenchyma and progressive loss of lung function, with a median survival following diagnosis of 2.5–3.5 years (Ley et al, 2011). The proliferation and migration of mesothelial cells and pericytes contribute to the development of fibroblast foci that form a complex, three-dimensional reticulum from the pleural surface into the lung parenchyma. The quantitative contribution of these respective sources of activated fibroblasts to the overall fibroplasia is controversial (see reviews: Kage and Borok, 2012; Bartis and Thickett, 2014; Bartis et al, 2014; Wolters et al, 2014; Mora et al, 2017), but unresolved in this condition which remains idiopathic. The mechanical changes lead to increased lung elasticity, restrictive ventilation impairment, and to respiratory failure (Raghu et al, 2011)

Methods

Results

Conclusion