Using human tissue models to illuminate the biology of fibrosis and to unlock new drug targets

Abstract

Organ fibrosis is a common endpoint for a broad spectrum of chronic diseases and represents a major cause of morbidity and mortality worldwide. Metabolic dysfunction-associated steatohepatitis (MASH), the fastest growing cause of liver fibrosis and idiopathic pulmonary fibrosis (IPF), the most common and severe interstitial lung disease, are prominent fibrotic diseases which pose an increasing socioeconomic burden. At present, therapeutic approaches are extremely limited and there is an urgent need to better understand mechanisms driving fibrosis to support development of new anti-fibrotics. There is spatial and temporal heterogeneity of pathological changes within human liver and lung tissue during fibrogenesis, which may correlate to changes in pathophysiological mediators of disease and clinical progression. In this project, we utilised cutting edge single nuclei RNA sequencing (snRNAseq) and 'omics technology to comprehensively characterise human liver and lung tissue at different stages of disease progression to identify key cellular phenotypes and molecular pathways driving fibrosis in MASH and IPF. Specifically, snRNAseq was performed on patient samples selected to represent the spectrum of MASH from F1–F4 fibrosis stage and cirrhosis, resulting in the identification of 9 targets of interest which were almost exclusively upregulated in disease-associated, high collagen type 1 expressing mesenchymal cell subpopulations. Concurrently, 'omics approaches were employed to dissect the molecular landscape of IPF by comparing macroscopically distinct regions of tissue from within the same IPF lung. Interrogation of protein heterogeneity identified novel proteins/pathways that are significantly upregulated in actively remodelling tissue for further investigation. To validate the translational relevance of these targets to human disease, precision-cut slices were generated from human liver and IPF lungs and challenged with candidate inhibitors targeting these proteins/pathways to assess anti-fibrotic and anti- inflammatory efficacy. Overall, our findings shed light on the complex cellular and molecular mechanisms underlying fibrosis progression and highlight promising targets for further development as novel anti- fibrotic therapies.