Fibroblasts Derived From Idiopathic Pulmonary Fibrosis (IPF) Patients Are Epigenetically Programmed to Induce Fibrogenic Responses in a Cell Autonomous Manner

Abstract Idiopathic pulmonary fibrosis (IPF) is a fatal progressive interstitial lung disease characterized by fibrotic scaring of the lungs that eventually leads to respiratory failure. Although repetitive lung injury following exposure to toxic chemicals or various pathogens can lead to fibrotic lung conditions, the etiology and progressive nature of IPF is unclear. Furthermore, whether exogenous lung insults, maladaptive immune responses, or cell-intrinsic re-programming drive disease progression remains unknown. Accumulation of myofibroblasts and extensive extracellular matrix deposition within the interstitium of the lung is a major hallmark of IPF. In this study, we have identified that IPF-donor derived human lung fibroblasts (IPF-F) had retained significantly elevated levels of total STAT3 compared to healthy-donor derived lung fibroblasts (HD-F). IPF-F also constitutively secreted elevated levels of several cytokines associated with fibrosis including IL-8, CXCL10 and CCL2, compared to HD-F. To determine the extent of re-programming in IPF-F, we performed a global and phospho-proteomic analysis and have identified a suite of pro-fibrotic mediators that are retained in IPF-F. These data suggest that IPF-F are putatively pathogenic and retain a pro-fibrotic phenotype. To determine whether these proteomic changes are transcriptionally or epigenetically engrained we carried out single-nuclear-multiome-sequencing on IPF-F and HD-F at both steady state and following stimulation with pro-fibrotic cytokines, oncostatin M, TGF-beta1 or IL-13. Together these studies have identified that IPF-F are re-programmed at epigenetic, transcriptional and translational levels of their past even after several rounds of passaging. We are currently testing a new pathogenic model where IPF-F retain cell-intrinsic memory and have the capacity to drive progressive fibrosis in the absence of exogenous stimuli.