Haag, L. | bioRxiv Science

bioRxiv2024

JUNB O-GlcNAcylation-mediated promoter accessibility of metabolic genes modulates distinct epithelial lineage in pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a lethal disease with substantial unmet medical needs. While aberrant epithelial remodelling is a key factor in IPF progression, the molecular mechanisms behind this process remain elusive. Using a patient-derived 3D distal airway epithelial organoid model, we successfully recapitulate important IPF features, including the emergence of aberrant KRT5+/COL1A1+ basal cells and a metabolic shift towards increased O-linked {beta}-N-acetylglucosamine (O-GlcNAc) levels. Consistent with this, single-cell analysis of accessible chromatin reveals an increased chromatin accessibility in these aberrant basal cells, particularly at JUNB motif-enriched promoter regions of metabolic genes. O-GlcNAcylation shapes JUNB function and promotes a pro-fibrotic response to chronic injury, leading to aberrant epithelial remodelling. Site-specific deletion of O-GlcNAcylation on JUNB attenuates the metaplastic differentiation of basal cells, thereby aiding in the restoration of the alveolar lineage. Together, these data establish a novel link between metabolic dysregulation, mediated by the O-GlcNAc-JUNB axis, and bronchiolization in IPF, offering new therapeutic strategies to treat this fatal disease.

cell biology↗

bioRxiv2020

Pulmonary stromal expansion and intra-alveolar coagulation are primary causes of Covid-19 death

Most Covid-19 victims are old and die from unrelated causes. Here we present twelve complete autopsies, including two rapid autopsies of young patients where the cause of death was Covid-19 ARDS. The main virus induced pathology was in the lung parenchyma and not in the airways. Most coagulation events occurred in the intra-alveolar and not in the intra-vascular space and the few thrombi were mainly composed of aggregated thrombocytes. The dominant inflammatory response was the massive accumulation of CD163+ macrophages and the disappearance of T killer, NK and B-cells. The virus was replicating in the pneumocytes and macrophages but not in bronchial epithelium, endothel, pericytes or stromal cells. The lung consolidations were produced by a massive regenerative response, stromal and epithelial proliferation and neovascularization. We suggest that thrombocyte aggregation inhibition, angiogenesis inhibition and general proliferation inhibition may have a roll in the treatment of advanced Covid-19 ARDS.

pathology↗