Bleomycin

Idiopathic pulmonary fibrosis (IPF) is a progressive lung disease with poor prognosis and limited treatment options. Efforts to identify effective treatments are thwarted by limited understanding of IPF pathogenesis and poor translatability of available preclinical models. Here we generated spatially resolved transcriptome maps of human IPF (n = 4) and bleomycin-induced mouse pulmonary fibrosis (n = 6) to address these limitations. We uncovered distinct fibrotic niches in the IPF lung, characterized by aberrant alveolar epithelial cells in a microenvironment dominated by transforming growth factor beta signaling alongside predicted regulators, such as TP53 and APOE. We also identified a clear divergence between the arrested alveolar regeneration in the IPF fibrotic niches and the active tissue repair in the acutely fibrotic mouse lung. Our study offers in-depth insights into the IPF transcriptional landscape and proposes alveolar regeneration as a promising therapeutic strategy for IPF.

Spermidine is an endogenous biological polyamine that plays various longevity-extending roles and exerts antioxidative, antiaging, and cell growth-promoting effects. We previously reported that spermidine levels were significantly reduced in idiopathic pulmonary fibrosis (IPF) of the lung. The present study assessed the potential beneficial effects of spermidine on lung fibrosis and investigated the possible mechanism. Lung fibrosis was established in mice using bleomycin (BLM), and exogenous spermidine was administered daily by intraperitoneal injection (50 mg/kg in phosphate-buffered saline). BLM-induced alveolar epithelial cells showed significant increases in apoptosis and endoplasmic reticulum stress (ERS)-related mediators, and spermidine attenuated BLM-induced apoptosis and activation of the ERS-related pathway. Senescence-associated β-gal staining and decreased expression of p16 and p21 showed that spermidine ameliorated BLM-induced premature cellular senescence. In addition, spermidine enhanced beclin-1-dependent autophagy and autophagy modulators in IPF fibroblasts and BLM-induced mouse lungs, in which inflammation and collagen deposition were significantly decreased. This beneficial effect was related to the antiapoptotic downregulation of the ERS pathway, antisenescence effects, and autophagy activation. Our findings suggest that spermidine could be a therapeutic agent for IPF treatment.

BackgroundIdiopathic pulmonary fibrosis (IPF) is a progressive and irreversible disease characterized by excessive fibroblast to myofibroblast differentiation with limited therapeutic options. Curdione, a sesquiterpene compound extracted from the essential oil of Curcuma aromatica Salisb, has anti-inflammatory and anti-tumor effects. However, the role of curdione in IPF is still unclear.MethodsThe effects of curdione were evaluated in a bleomycin (BLM)-induced pulmonary fibrosis mouse model. C57BL/6 mice were treated with BLM on day 0 by intratracheal injection and intraperitoneal administered curdione or vehicle. In vitro study, expression of fibrotic protein was examined and the transforming growth factor (TGF)-β-related signaling was evaluated in human pulmonary fibroblasts (HPFs) treated with curdione following TGF-β1 stimulation.ResultsHistological and immunofluorescent examination showed that curdione alleviated BLM-induced lung injury and fibrosis. Specifically, curdione significantly attenuated fibroblast to myofibroblast differentiation in the lung in BLM induced mice. Furthermore, curdione also decreased TGF-β1 induced fibroblast to myofibroblast differentiation in vitro, as evidenced by low expression of α-SMA, collagen 1 and fibronectin in a dose dependent manner. Mechanistically, curdione suppressed the phosphorylation of Smad3 following TGF-β1 treatment, thereby inhibiting fibroblast differentiation.ConclusionsOverall, curdione exerted therapeutic effects against pulmonary fibrosis via attenuating fibroblast to myofibroblast differentiation. As curdione had been shown to be safe and well-tolerated in BLM-induced mouse model, curdione might be useful for developing novel therapeutics for IPF.

Pulmonary fibrosis (PF) is a disease characterized by dysregulated extracellular matrix deposition and aberrant fibroblast activation. Emerging evidence implicates that dysregulated copper metabolism contributed to fibrotic pathogenesis, yet its role and the therapeutic potential of copper modulation remain underexplored. This study investigated the involvement of cuproptosis, a programmed cell death induced by intracellular copper overload, in PF and evaluated the therapeutic efficacy of the copper chelator tetrathiomolybdate (TTM). In a bleomycin (BLM)-induced murine PF model, intratracheal BLM administration elevated lung copper levels, upregulated oligomerized DLAT, and exacerbated fibrosis, as evidenced by collagen deposition, α-smooth muscle actin, and transforming growth factor-beta expression. TTM treatment significantly attenuated fibrotic progression, reduced oxidative stress, and suppressed Olig-DLAT accumulation. In vitro, copper ionophores induced cuproptosis in bronchial epithelial cells, characterized by reduced viability, elevated intracellular Cu⁺, and Olig-DLAT aggregation, which were reversed by TTM. Furthermore, TTM mitigated TGF-β-driven epithelial-mesenchymal transition (EMT) and fibroblast-to-myofibroblast transition (FMT), downregulating collagen-1 and restoring E-cadherin expression. These findings establish cuproptosis as a novel mechanistic contributor to PF and highlight TTM's dual role in restoring copper homeostasis and inhibiting fibrogenic pathways, offering a promising therapeutic strategy for fibrotic lung diseases.