High-Throughput Drug Screening of ECM Deposition Inhibitors for Antifibrotic Drug Discovery

Idiopathic lung fibrosis (IPF) is a progressive interstitial lung disease with a median patient survival of 3 – 5 years. Up to now, no approved pharmacotherapeutic is able to stop the disease progression in IPF patients. Therefore, the discovery of novel potential IPF therapeutics represents a major medical need. A growing body of evidence indicates a pivotal role of excessive altered ECM deposition in IPF, which is driving disease progression and loss of lung function. We developed a new phenotypic high-throughput drug discovery assay for identifying novel fibrotic ECM deposition inhibitors. Primary IPF patient derived lung fibroblasts were activated by transforming growth factor β (TGFβ1) to trigger transdifferentiation into myofibroblasts and a concomitant increase in ECM deposition, both of which are defining hallmarks of IPF. Live immunolabeling of deposited ECM molecules and an automated confocal imaging in a 384-well plate format, coupled to an automated 3D image analysis, resulted in a confident assessment of the alterations in the ECMʼs deposition. Subsequent screening 1039 FDA/EMA approved drugs (Prestwick library) resulted in the identification of potential 22 ECM-deposition-inhibitors for drug repurposing. These hits clustered in drug classes, including cardiac glycosides and ACE inhibitors. In conclusion, we established a phenotypic screening pipeline for the discovery of novel potential antifibrotic pharmacotherapeutics and performed a proof-of-concept study. The identified drug candidates will be further validated in a fibrotic ex-vivo tissue culture system of human precision-cut-lung slices (PCLS) to select the best candidates for an in-vivo validation in a fibrosis animal model. In conclusion, we strongly believe that our innovative approach opens new paths for an unbiased antifibrotic drug discovery and furthermore is apt for the screening of large small molecule based libraries.