Vancheri, Carlo

Idiopathic pulmonary fibrosis (IPF) is a fatal, aging-related disease characterized by persistent lung fibroblast activation, progressive lung scarring, and several vascular abnormalities. We have previously demonstrated that aging-associated vascular dysfunction drives maladaptive endothelial responses to injury and exacerbates lung fibrosis via secretion of profibrotic endothelial cell–derived factors. However, regulatory mechanisms governing endothelial dysfunction during progressive lung fibrosis remain poorly understood. Here, using preclinical mouse models of progressive lung fibrosis as well as human IPF lungs, we demonstrate that miR-205-5p was overexpressed in lung endothelial cells (ECs) from fibrotic lungs and coordinated gene expression programs implicated in endothelial dysfunction and progressive fibrosis. Mechanistically, miR-205-5p induced senescence in lung ECs, mirroring the senescent phenotype of IPF lung ECs. Consistently, conditioned medium derived from lung ECs overexpressing miR-205-5p promoted lung fibroblast activation. Importantly, miR-205-5p inhibition in IPF lung ECs attenuated endothelial senescence and limited paracrine fibroblast activation. Finally, inhibition of miR-205-5p in vivo preserved the pulmonary vascular network and attenuated lung fibrosis progression in aged mice challenged with bleomycin. Collectively, our findings support what we believe to be a novel connection among lung endothelial miR-205-5p, endothelial senescence, and profibrotic alteration of the endothelial secretome and highlight miR-205-5p inhibition as a potential therapeutic intervention for pulmonary fibrosis.

This study demonstrates that circulating extracellular vesicles (cEVs) isolated from young mice reverse the transcriptional alterations of the aged mouse pulmonary vasculature, leading to a more youthful endothelial transcriptional phenotype. As a result of this vascular phenotype, aged mice are protected from bleomycin-induced pulmonary fibrosis. These findings highlight the therapeutic potential of targeting vascular aging to alleviate pulmonary fibrosis.

Abstract RATIONALE: Vascular dysfunction contributes to pathological tissue remodeling in aging-associated disease such as Idiopathic Pulmonary Fibrosis (IPF). IPF is an incurable lung disease characterized by progressive accumulation of scar-forming fibroblasts and several vascular alterations, including endothelial transcriptional changes leading to a pro-fibrotic endothelial secretory phenotype. To date, the mechanisms governing these transcriptional changes remain largely unexplored. To fill this gap, we sought to investigate whether microRNAs (miRNAs), small non-coding RNA that function as key gene expression regulators, modulate the transcriptional changes of the endothelium associated with progressive pulmonary fibrosis. METHODS AND RESULTS: miRNA expression profiling of lung ECs (LECs) sorted from aged mice with persistent lung fibrosis revealed upregulation of miR-205-5p. Further analysis demonstrated that endothelial miR-205-5p was strongly upregulated in an additional mouse model of progressive lung fibrosis induced by repetitive bleomycin dose as well as in human LECs purified from IPF lungs. RNA-seq analysis of normal human LECs overexpressing miR-205-5p revealed reduction of genes associated to endothelial identity (e.g. PECAM1, ERG, NOS3), and an increase of genes encoding for soluble pro-inflammatory and pro-fibrotic molecules, including TGFBI, TGFB2, TGFB3, CXCL10, CCL5, IL1B and FAS compared to normal LECs transfected with a control mimic. Consistently, conditioned medium from miR-205-5p overxpressing LECs exerted a pro-fibrotic activity on quiescent human lung fibroblasts, as demonstrated by upregulation of a panel of profibrotic transcripts (e.g. COL1A1, CTHRC1, FN1 and TNC) and elevated Collagen I deposition compared to human lung fibroblasts exposed to conditioned medium generated by human LECs transfected with a control mimic. CONCLUSION: Altogether, our findings suggest that lung endothelail miR-205-5p induces loss of endothelial cell identity and drives the secretion of pro-fibrotic molecules that promote the transition of quiescent fibroblasts into scar-forming fibroblast through paracrine signal. Our data set the stage for further investigations into the role of miR-205-5p and associated pathways in lung vascular injury responses, with the long term goal of targeting endothelial dysfunction for slowing the progression of pulmonary fibrosis.

Abstract Rationale Lung biopsy (LBx) has a relevant role in the prediction of prognosis of interstitial lung diseases (ILDs), but its impact on the clinical management of patients remains unexplored. Objectives This study evaluates whether LBx may change the therapeutic strategy and assesses the effect of diagnostic reclassification after LBx on long-term prognosis. Methods We evaluated the LBx of 426 consecutive patients with ILDs, without a definite usual interstitial pneumonia pattern on high-resolution computed tomographic imaging. A total of 266 patients underwent transbronchial lung cryobiopsy (TBLC), and 160 patients underwent surgical lung biopsy (SLB). The multidisciplinary team (MDT) determined a diagnosis with high or low confidence, and a management strategy, both before and after the LBx data. Results Final MDT diagnoses were 189 idiopathic pulmonary fibrosis (IPF), 143 non-IPF fibrotic ILDs, and 94 nonfibrotic ILDs. LBx data changed the management strategy in 145 cases (34%), with similar results for TBLC and SLB (the treatment strategy changed in 31.5% of TBLC cases, 84/266, P < 0.001, and in 38% of SLB, 61/160, P < 0.001). After LBx, the MDT was less inclined to “wait and see” (from 15% to 4% of cases, P < 0.001) or to prescribe steroids only (from 54% to 37%, P < 0.001) and was more confident to treat with antifibrotics (from 23% to 44%, P < 0.001) or immunosuppressive drugs (from 7% to 14%, P < 0.001). The therapeutic strategy changed in 70% of reclassified cases (60/85) and in 59% of cases in which LBx increased the MDT confidence (84/142). Reclassification significantly impacted the outcome. The cases classified as non-IPF by clinician and radiologist and then reclassified to be IPF after LBx showed a significantly worse survival compared with non-IPF confirmed cases (adjusted hazard ratio [HR], 3.8; 95% confidence interval [CI], 1.75–8.3); P = 0.001. Cases initially classified as IPF and then reclassified as non-IPF after LBx showed a better prognosis compared with IPF confirmed cases (HR, 0.41; 95% CI, 0.18–0.94; P = 0.03). Conclusions Reclassification of cases with LBx data increased diagnostic confidence and changed the therapeutic strategy in one-third of cases. Pathologic reclassification of cases refined prognosis prediction. Patients classified as non-IPF by clinician and radiologist and then reclassified IPF after LBx had worse prognosis compared with the non-IPF confirmed cases.