Lung Microenvironments and Disease Progression in Fibrotic Hypersensitivity Pneumonitis
Laurens J. De Sadeleer, John E. McDonough, Jonas C. Schupp, Xiting Yan, Arno Vanstapel, Anke Van Herck, Stephanie Everaerts, Vincent Geudens, Annelore Sacreas, Tinne Goos, Celine Aelbrecht, Tim S. Nawrot, Dries S. Martens, Dominique Schols, Sandra Claes, Johny A. Verschakelen, Eric K. Verbeken, Maximilian Ackermann, Anabelle Decottignies, Manon Mahieu, Tillie-Louise Hackett, James C. Hogg, Bart M. Vanaudenaerde, Stijn E. Verleden, Naftali Kaminski, Wim A. Wuyts
Abstract
Abstract Rationale Fibrotic hypersensitivity pneumonitis (fHP) is an interstitial lung disease caused by sensitization to an inhaled allergen. Objectives To identify the molecular determinants associated with progression of fibrosis. Methods Nine fHP explant lungs and six unused donor lungs (as controls) were systematically sampled (4 samples/lung). According to microcomputed tomography measures, fHP cores were clustered into mild, moderate, and severe fibrosis groups. Gene expression profiles were assessed using weighted gene co-expression network analysis, xCell, gene ontology, and structure enrichment analysis. Gene expression of the prevailing molecular traits was also compared with idiopathic pulmonary fibrosis (IPF). The explant lung findings were evaluated in separate clinical fHP cohorts using tissue, BAL samples, and computed tomography scans. Measurements and Main Results We found six molecular traits that associated with differential lung involvement. In fHP, extracellular matrix and antigen presentation/sensitization transcriptomic signatures characterized lung zones with only mild structural and histological changes, whereas signatures involved in honeycombing and B cells dominated the transcriptome in the most severely affected lung zones. With increasing disease severity, endothelial function was progressively lost, and progressive disruption in normal cellular homeostatic processes emerged. All six were also found in IPF, with largely similar associations with disease microenvironments. The molecular traits correlated with in vivodisease behavior in a separate clinical fHP cohort. Conclusions We identified six molecular traits that characterize the morphological progression of fHP and associate with in vivoclinical behavior. Comparing IPF with fHP, the transcriptome landscape was determined considerably by local disease extent rather than by diagnosis alone.