Mouse Model Of Pulmonary Fibrosis Research Articles

Taraxerone exerts antipulmonary fibrosis effect through Smad signaling pathway and antioxidant stress response in a Sirtuin1-dependent manner.

Idiopathic pulmonary fibrosis treatments are limited, often with severe side effects, highlighting the need for novel options. Taraxerone has diverse biomedical properties, but its mechanism remains unclear. This study investigates taraxerone's impact and the mechanisms involved in bleomycin-induced pulmonary fibrosis in mice. After establishing a pulmonary fibrosis mouse model, taraxerone was intraperitoneally injected continuously for 14-28 days. The in vivo antifibrotic and antioxidative stress effects of taraxerone were assessed. In vitro, the influence of taraxerone on transforming growth factor-β1-induced myofibroblast transformation and oxidative stress was investigated. Subsequently, quantitative polymerase chain reaction screened the histone deacetylase and Sirtuin family, and taraxerone's effects on SIRT1 were assessed. After SIRT1 siRNA treatment, changes in myofibroblast transformation and antioxidant capacity in response to taraxerone were observed. Acetylation and phosphorylation levels of Smad3 were evaluated. We also examined the binding levels of SIRT1 with Pho-Smad3 and Smad3, as well as the nuclear localization of Smad2/3. EX527 confirmed SIRT1's in vivo action in response to taraxerone. In vitro experiments suggested that taraxerone inhibited myofibroblast differentiation by activating SIRT1 and reducing oxidative stress. We also observed a new interaction between SIRT1 and the Smad complex. Taraxerone activates SIRT1, enabling it to bind directly to Smad3. This leads to reduced Smad complex phosphorylation and limited nuclear translocation. As a result, the transcription of fibrotic factors is reduced. In vivo validation confirms taraxerone's SIRT1-mediated antifibrotic effectiveness. This suggests that targeting SIRT1-mediated inhibition of myofibroblast differentiation could be a key strategy in taraxerone-based therapy for pulmonary fibrosis.

Lactate facilitated mitochondrial fission-derived ROS to promote pulmonary fibrosis via ERK/DRP-1 signaling

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, fibrotic interstitial lung diseases, which mainly existed in middle-aged and elderly people. The accumulation of reactive oxygen species (ROS) is a common characteristic of IPF. Previous research also shown that lactate levels can be abnormally elevated in IPF patients. Emerging evidence suggested a relationship between lactate and ROS in IPF which needs further elucidation. In this article, we utilized a mouse model of BLM-induced pulmonary fibrosis to detect alterations in ROS levels and other indicators associated with fibrosis. Lactate could induce mitochondrial fragmentation by modulating expression and activity of DRP1 and ERK. Moreover, Increased ROS promoted P65 translocation into nucleus, leading to expression of lung fibrotic markers. Finally, Ulixertinib, Mdivi-1 and Mito-TEMPO, which were inhibitor activity of ERK, DRP1 and mtROS, respectively, could effectively prevented mitochondrial damage and production of ROS and eventually alleviate pulmonary fibrosis. Taken together, these findings suggested that lactate could promote lung fibrosis by increasing mitochondrial fission-derived ROS via ERK/DRP1 signaling, which may provide novel therapeutic solutions for IPF.

Phospholipids of inhaled liposomes determine the in vivo fate and therapeutic effects of salvianolic acid B on idiopathic pulmonary fibrosis

Since phospholipids have an important effect on the size, surface potential and hardness of liposomes that decide their in vivo fate after inhalation, this research has systematically evaluated the effect of phospholipids on pulmonary drug delivery by liposomes. In this study, liposomes composed of neutral saturated/unsaturated phospholipids, anionic and cationic phospholipids were constructed to investigate how surface potential and the degree of saturation of fatty acid chains determined their mucus and epithelium permeability both in vitro and in vivo. Our results clearly indicated that liposomes composed of saturated neutral and anionic phospholipids possessed high stability and permeability, compared to that of liposomes composed of unsaturated phospholipids and cationic phospholipids. Furthermore, both in vivo imaging of fluorescence-labeled liposomes and biodistribution of salvianolic acid B (SAB) that encapsulated in liposomes were performed to estimate the effect of phospholipids on the lung exposure and retention of inhaled liposomes. Finally, inhaled SAB-loaded liposomes exhibited enhanced therapeutic effects in a bleomycin-induced idiopathic pulmonary fibrosis mice model via inhibition of inflammation and regulation on coagulation-fibrinolytic system. Such findings will be beneficial to the development of inhalable lipid-based nanodrug delivery systems for the treatment of respiratory diseases where inhalation is the preferred route of administration.

Pulmonary Fibrosis Augments CGRP-Dependent Hyperpolarization and Vasodilation of Mouse Pulmonary Arteries

Calcitonin gene related peptide (CGRP) hyperpolarizes membrane potential (Vm) of pulmonary arterial smooth muscle cells (SMCs) and endothelial cells (ECs) through PKA-dependent activation of KATP channels. CGRP can diminish the severity of pulmonary fibrosis (PF), however, the effects on vascular signaling were poorly defined. We hypothesized that hyperpolarization to CGRP would be augmented in a mouse model of PF. PF was induced by intratracheal delivery of bleomycin (3 wk), and saline was used as a control (sham). Pulmonary arteries (PAs; 100-150 μm diameter) from male C57BL/6J mice (age, ~5 mo), were cannulated, pressurized to 16 cmH2O, and studied at 37°C. Alternatively, intact endothelial tubes were studied at 32°C following dissociation of SMCs. Vm was recorded continuously using intracellular microelectrodes. At rest, Vm was similar for SMCs (bleomycin = -43±3 mV, sham = -44±3 mV; n = 5/group) and ECs (bleomycin = -45±4 mV, sham = -44±3 mV; n=5/group). Increasing concentrations of CGRP (10−10-10−6 M) evoked hyperpolarization of Vm with greater potency in SMCs (EC50: bleomycin = 2 nM, sham = 15 nM) and ECs (EC50: bleomycin = 3 nM, sham = 8 nM) from PF mice, without changing effcacy (SMCs: bleomycin ΔVm = -24±4 mV, sham ΔVm = -21±3 mV; ECs: bleomycin ΔVm = -26±2 mV, sham ΔVm=23±4 mV). Consistently, vasodilation to CGRP in PAs preconstricted with uridine triphosphate (UTP, 5 μM; EC50) was enhanced in PF (92±6% maximum dilation;) vs. sham (83±4% maximum dilation) mice (n=5/group). Greater vasodilation and hyperpolarization of SMCs to CGRP persisted in endothelium-disrupted PAs and during treatment with L-NAME (10−4 M) indicating that ECs are not required for greater responsiveness to CGRP in SMCs. With no effect on resting Vm, inhibition of KATP channels with 1 μM glibenclamide or PKA with protein kinase inhibitor [PKI-(14-22)-amide, myristoylated; 1 μM] significantly attenuated (p<0.05) hyperpolarization of SMCs and ECs (ΔVm ≤5 mV for all groups). Both glibenclamide and PKI attenuated vasodilation to CGRP in PAs and eliminated differences between groups. In a mouse model of PF, CGRP-dependent hyperpolarization of pulmonary arterial SMCs and ECs is augmented through increased PKA-dependent activation of KATP channels leading to increased vasodilator sensitivity. AHA CDA#931652. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

BACH1 transcriptionally upregulates FOSL2 to induce M2 macrophages phenotype by activating TGFβ/SMAD signaling to promote the transformation of lung fibroblasts into myofibroblasts

Pulmonary fibrosis is a chronic and progressive lung disorder. The pro-fibrosis factors induced by M2 macrophage phenotype promote the differentiation of fibroblasts into myofibroblasts, which is essential for pulmonary fibrosis. We aimed to explore the role and mechanism of BTB domain and CNC homology 1 (BACH1) in pulmonary fibrosis. BACH1 was knocked down in THP‐1 polarized M2 macrophages with or without FOS-like antigen 2 (FOSL2) overexpression, the expression of M2 macrophage markers was detected. Cell viability, migration, invasion and extracellular matrix (ECM) accumulation were estimated by CCK-8, wound healing, transwell, western bot and immunofluorescence staining. Luciferase reporter and chromatin immunoprecipitation assays were used to verify the binding of BACH1 to FOSL2 promotor region. In vivo, a bleomycin (BLM)-induced pulmonary fibrosis mice model was established to evaluate the effect of BACH1 silencing on the histopathological changes, M2 macrophage phenotype and extracellular matrix (ECM) deposition. Expression of proteins was assessed with western blot. Results indicated that BACH1 expression was upregulated in M2 macrophages polarized from THP-1 cells. BACH1 deficiency inhibited the polarization of THP-1 to the M2 macrophage phenotype to promote the transformation of lung fibroblasts into myofibroblasts. Additionally, BACH1 could transcriptionally activate FOSL2 expression in THP-1-derived macrophages to upregulate TGFβ/SMAD signaling in HFL-1 cells. The animal experiments indicated that BACH1 knockdown alleviated BLM-induced pulmonary fibrosis, M2 macrophage polarization and inactivated FOSL2/TGFβ/SMAD signaling in mice lung tissues. Together, this finding suggests BACH1/FOSL2 may be useful therapeutic targets for the treatment of pulmonary fibrosis.

BPA promotes lung fibrosis in mice by regulating autophagy-dependent ferroptosis in alveolar epithelial cells

BackgroundBisphenol A (BPA) is an industrial chemical that is commonly found in daily consumer products. BPA is reportedly associated with lung diseases. However, the impact of BPA on pulmonary fibrosis (PF) and its possible mechanisms of action both remain unclear. MethodsA PF mouse model was induced by bleomycin (BLM). Mouse lung fibroblasts (MLG 2908) and mouse alveolar epithelial cells (MLE-12) were treated with BPA to establish a PF cell model. Tissue staining, CCK-8 assays, western blot experiments and relevant indicator kits were used to detect and evaluate the effect of BPA on PF. ResultsBPA dose-dependently promoted oxidative stress and induced ferroptosis, leading to PF. The ferroptosis inhibitor Fer-1 partly attenuated the effect of BPA. In addition, among the two main cell types associated with the progression of PF, MLE-12 cells are more sensitive to BPA than are MLG 2908 cells, and BPA induces ferroptosis in MLE-12 cells. Furthermore, BPA promoted autophagy-mediated ferroptosis by activating the AMPK/mTOR signaling pathway, thereby exacerbating the progression of PF. The autophagy inhibitor CQ1 partly attenuated the effect of BPA. ConclusionBPA promotes the progression of PF by promoting autophagy-dependent ferroptosis in alveolar epithelial cells, which provides a new theoretical basis for understanding BPA-induced PF.

Mimosa pudica L. extract ameliorates pulmonary fibrosis via modulation of MAPK signaling pathways and FOXO3 stabilization

Ethnopharmacological relevanceIdiopathic pulmonary fibrosis (IPF) is a progressive fibrosing pulmonary disorder that has a poor prognosis and high mortality. Although there has been extensive effort to introduce several new anti-fibrotic agents in the past decade, IPF remains an incurable disease. Mimosa pudica L., an indigenous Vietnamese plant, has been empirically used to treat respiratory disorders. Nevertheless, the therapeutic effects of M. pudica (MP) on lung fibrosis and the mechanisms underlying those effects remain unclear. Aim of the studyThis study investigated the protective effect of a crude ethanol extract of the above-ground parts of MP against pulmonary fibrogenesis. Materials and methodsInflammatory responses triggered by TNFα in structural lung cells were examined in normal human lung fibroblasts and A549 alveolar epithelial cells using Western blot analysis, reverse transcription–quantitative polymerase chain reaction assays, and immunocytochemistry. The epithelial-to-mesenchymal transition (EMT) was examined via cell morphology observations, F-actin fluorescent staining, gene and protein expression measurements, and a wound-healing assay. Anti-fibrotic assays including collagen release, differentiation, and measurements of fibrosis-related gene and protein expression levels were performed on TGFβ-stimulated human lung fibroblasts and lung fibroblasts derived from mice with fibrotic lungs. Finally, in vitro anti-fibrotic activities were validated using a mouse model of bleomycin-induced pulmonary fibrosis. ResultsMP alleviated the inflammatory responses of A549 alveolar epithelial cells and lung fibroblasts, as revealed by inhibition of TNFα-induced chemotactic cytokine and chemokine expression, along with inactivation of the MAPK and NFκB signalling pathways. MP also partially reversed the TGFβ-promoted EMT via downregulation of mesenchymal markers in A549 cells. Importantly, MP decreased the expression levels of fibrosis-related genes/proteins including collagen I, fibronectin, and αSMA; moreover, it suppressed collagen secretion and prevented myofibroblast differentiation in lung fibroblasts. These effects were mediated by FOXO3 stabilization through suppression of TGFβ-induced ERK1/2 phosphorylation. MP consistently protected mice from the onset and progression of bleomycin-induced pulmonary fibrosis. ConclusionThis study explored the multifaceted roles of MP in counteracting the pathobiological processes of lung fibrosis. The results suggest that further evaluation of MP could yield candidate therapies for IPF.

SEMA3B inhibits TGFβ-induced extracellular matrix protein production and its reduced levels are associated with a decline in lung function in IPF.

Idiopathic pulmonary fibrosis (IPF) is marked by the activation of fibroblasts, leading to excessive production and deposition of extracellular matrix (ECM) within the lung parenchyma. Despite the pivotal role of ECM overexpression in IPF, potential negative regulators of ECM production in fibroblasts have yet to be identified. Semaphorin class 3B (SEMA3B), a secreted protein highly expressed in lung tissues, has established roles in axonal guidance and tumor suppression. However, the role of SEMA3B in ECM production by fibroblasts in the pathogenesis of IPF remains unexplored. Here, we show the downregulation of SEMA3B and its cognate binding receptor, neuropilin 1 (NRP1) in IPF lungs compared with healthy controls. Notably, the reduced expression of SEMA3B and NRP1 is associated with a decline in lung function in IPF. The downregulation of SEMA3B and NRP1 transcripts was validated in the lung tissues of patients with IPF, and two alternative mouse models of pulmonary fibrosis. In addition, we show that TGFβ functions as a negative regulator of SEMA3B and NRP1 expression in lung fibroblasts. Furthermore, we demonstrate the anti-fibrotic effects of SEMA3B against TGFβ-induced ECM production in IPF lung fibroblasts. Overall, our findings uncovered a novel role of SEMA3B in the pathogenesis of pulmonary fibrosis and provided novel insights into modulating the SEMA3B-NRP1 axis to attenuate pulmonary fibrosis.

Aging of alveolar type 2 cells induced by Lonp1 deficiency exacerbates pulmonary fibrosis.

Idiopathic pulmonary fibrosis (IPF) is a progressive and chronic disease that significantly impacts patient quality of life, and its incidence is on the rise. The pathogenesis of IPF remains poorly understood. Alveolar type 2 (AT2) cells are crucial in the onset and progression of IPF, yet the specific mechanisms involved are not well defined. Lon protease 1 (LONP1), known for its critical roles in various diseases, has an unclear function in IPF. Our research investigated the impact of Lonp1 gene deletion on AT2 cell functionality and its subsequent effect on IPF development. We generated a bleomycin-induced pulmonary fibrosis mouse model with a targeted Lonp1 knockout in AT2 cells and assessed the consequences on AT2 cell function and fibrosis progression. Additionally, we constructed the MLE12 cells with stable Lonp1 knockdown and utilized transcriptome sequencing to identify pathways altered by the Lonp1 knockdown. Our results indicated that mice with AT2 cell-specific Lonp1 knockout exhibited more severe fibrosis compared to controls. These mice exhibited a reduction in AT2 and AT1 cell populations, along with an increase in p53- and p21-positive AT2 cells. Lonp1 knockdown in MLE12 cells led to the upregulation of aging-associated pathways, with fibroblast growth factor 2 (Fgf2) gene emerging as a central gene interconnecting these pathways. Therefore, loss of Lonp1 appears to promote AT2 cell aging and exacerbate bleomycin-induced pulmonary fibrosis. Fgf2 emerges as a pivotal downstream gene associated with cellular senescence. This study uncovers the role of the Lonp1 gene in pulmonary fibrosis, presenting a novel target for investigating the pathological mechanisms and potential therapeutic approaches for IPF.

407 The OGT/O-GlcNAc Axis Regulates Fibrosis Resolution in Idiopathic Pulmonary Fibrosis

OBJECTIVES/GOALS: Idiopathic pulmonary fibrosis (IPF) is a chronic lung disease characterized by dysregulated collagen accumulation in the lung parenchyma. Our goal is to investigate the role of O-linked N-Acetylglucosamine (O-GlcNAc) transferase (OGT) in pulmonary fibrosis to ultimately discover novel therapies for fibrosis resolution. METHODS/STUDY POPULATION: Lung tissue from IPF and non-IPF donors was subjected to immunohistochemistry (IHC) to assess O-GlcNAc levels. Primary human lung fibroblasts were treated with OGT or O-GlcNAcase (OGA) inhibitors followed by transforming growth factor-beta 1 (TGF-β1) stimulation to assess O-GlcNAc regulation of fibroblast-to-myofibroblast transition (FMT) markers [alpha smooth muscle actin (α-SMA) and type 1 and type 3 collagen (COL1α1, COL3α1)] In Drosophila melanogaster, OGT knockdown (KD)/overexpression (OE) was conditionally induced to assess pericardin, a type IV collagen-like protein, regulation by immunofluorescence. Lastly, a mouse model of bleomycin-induced pulmonary fibrosis was examined following OGT KD and assessed for fibrosis resolution via histology, hydroxyproline assay, and western blotting. RESULTS/ANTICIPATED RESULTS: O-GlcNAc staining was increased in IPF lung tissue compared to non-IPF control lungs. In primary human lung fibroblasts, TGF-α1 administration resulted in increased FMT markers (α-SMA, COL1α1, and COL3α1), which were reduced or increased by OGT or OGA inhibition, respectively. Genetic manipulation in the Drosophila models showed decreased pericardin expression with OGT KD compared to the wild-type, whereas OGT OE increased pericardin compared to control. Additionally, OGT KD in bleomycin treated aged mice resulted in reduced collagen levels at the transcript and protein level and concurrent fibrosis resolution as assessed by Masson’s trichrome staining and total hydroxyproline analysis. Collectively, showing OGT/O-GlcNAc regulating collagen in fibrosis resolution. DISCUSSION/SIGNIFICANCE: These data suggest that the OGT/O-GlcNAc axis regulates collagen deposition in pulmonary fibrosis, and we show that O-GlcNAc is implicated in the pathogenesis of IPF. We identified OGT as a therapeutic target to overcome current drug limitations, opening new horizons for biomedical treatment.

Attenuation of fibroblast activation and fibrosis by adropin in systemic sclerosis.

Fibrotic diseases impose a major socioeconomic challenge on modern societies and have limited treatment options. Adropin, a peptide hormone encoded by the energy homeostasis-associated (ENHO) gene, is implicated in metabolism and vascular homeostasis, but its role in the pathogenesis of fibrosis remains enigmatic. Here, we used machine learning approaches in combination with functional in vitro and in vivo experiments to characterize adropin as a potential regulator involved in fibroblast activation and tissue fibrosis in systemic sclerosis (SSc). We demonstrated consistent down-regulation of adropin/ENHO in skin across multiple cohorts of patients with SSc. The prototypical profibrotic cytokine TGFβ reduced adropin/ENHO expression in a JNK-dependent manner. Restoration of adropin signaling by therapeutic application of bioactive adropin34-76 peptides in turn inhibited TGFβ-induced fibroblast activation and fibrotic tissue remodeling in primary human dermal fibroblasts, three-dimensional full-thickness skin equivalents, mouse models of bleomycin-induced pulmonary fibrosis and sclerodermatous chronic graft-versus-host-disease (sclGvHD), and precision-cut human skin slices. Knockdown of GPR19, an adropin receptor, abrogated the antifibrotic effects of adropin in fibroblasts. RNA-seq demonstrated that the antifibrotic effects of adropin34-76 were functionally linked to deactivation of GLI1-dependent profibrotic transcriptional networks, which was experimentally confirmed in vitro, in vivo, and ex vivo using cultured human dermal fibroblasts, a sclGvHD mouse model, and precision-cut human skin slices. ChIP-seq confirmed adropin34-76-induced changes in TGFβ/GLI1 signaling. Our study characterizes the TGFβ-induced down-regulation of adropin/ENHO expression as a potential pathomechanism of SSc as a prototypical systemic fibrotic disease that unleashes uncontrolled activation of profibrotic GLI1 signaling.

Tetrandrine alleviates pulmonary fibrosis by inhibiting alveolar epithelial cell senescence through PINK1/Parkin-mediated mitophagy

Idiopathic pulmonary fibrosis (IPF) is a fatal and insidious interstitial lung disease. So far, there are no effective drugs for preventing the disease process. Cellular senescence plays a critical role in the development of IPF, with the senescence and insufficient mitophagy of alveolar epithelial cells being implicated in its pathogenesis. Tetrandrine is a natural alkaloid which is now produced synthetically. It was known that the tetrandrine has anti-fibrotic effects, but the efficacy and mechanisms are still not well evaluated. Here, we reveal the roles of tetrandrine on AECs senescence and the antifibrotic effects by using a bleomycin challenged mouse model of pulmonary fibrosis and a bleomycin-stimulated mouse alveolar epithelial cell line (MLE-12). We performed the β-galactosidase staining, immunohistochemistry and fluorescence to assess senescence in MLE-12 cells. The mitophagy levels were detected by co-localization of LC3 and COVIX. Our findings indicate that tetrandrine suppressed bleomycin-induced fibroblast activation and ultimately blocked the increase of collagen deposition in mouse model lung tissue. It has significantly inhibited the bleomycin-induced senescence and senescence-associated secretory phenotype (SASP) in alveolar epithelial cells (AECs). Mechanistically, tetrandrine suppressed the decrease of mitochondrial autophagy-related protein expression to rescue the bleomycin-stimulated impaired mitophagy in MLE-12 cells. We revealed that knockdown the putative kinase 1 (PINK1) gene by a short interfering RNA (siRNA) could abolish the ability of tetrandrine and reverse the MLE-12 cells senescence, which indicated the mitophagy of MLE-12 cells is PINK1 dependent. Our data suggest the tetrandrine could be a novel and effective drug candidate for lung fibrosis and senescence-related fibrotic diseases.

Cuproptosis-associated hub gene identification and immune cell infiltration patterns in silicosis

Recent research has hinted at a potential connection between silicosis, a fibrotic lung disease caused by exposure to crystalline silica particles, and cuproptosis. The aim of the study was to explore how cuproptosis-related genes (CRGs) may influence the development of silicosis and elucidate the underlying mechanisms. An analysis of genes associated with both silicosis and cuproptosis was conducted. Key gene identification was achieved through the application of two machine learning techniques. Additionally, the correlation between these key genes and immune cell populations was explored and the critical pathways were discerned. To corroborate our findings, the expression of key genes was verified in both a publicly available silica-induced mouse model and our own silicosis mouse model. A total of 12 differentially expressed CRGs associated with silicosis were identified. Further analysis resulted in the identification of 6 CRGs, namely LOX, SPARC, MOXD1, ALB, MT-CO2, and AOC2. Elevated immune cell infiltration of CD8 T cells, regulatory T cells, M0 macrophages, and neutrophils in silicosis patients compared to healthy controls was indicated. Validation in a silica-induced pulmonary fibrosis mouse model supported SPARC and MT-CO2 as potential signature genes for the prediction of silicosis. These findings highlight a strong association between silicosis and cuproptosis. Among CRGs, LOX, SPARC, MOXD1, ALB, MT-CO2, and AOC2 emerged as pivotal players in the context of silicosis by modulating CD8 T cells, regulatory T cells, M0 macrophages, and neutrophils.

Niclosamide - encapsulated lipid nanoparticles for the reversal of pulmonary fibrosis

Pulmonary fibrosis (PF) is a serious and progressive fibrotic interstitial lung disease that is possibly life-threatening and that is characterized by fibroblast accumulation and collagen deposition. Nintedanib and pirfenidone are currently the only two FDA-approved oral medicines for PF. Some drugs such as antihelminthic drug niclosamide (Ncl) have shown promising therapeutic potentials for PF treatment. Unfortunately, poor aqueous solubility problems obstruct clinical application of these drugs. Herein, we prepared Ncl-encapsulated lipid nanoparticles (Ncl-Lips) for pulmonary fibrosis therapy. A mouse model of pulmonary fibrosis induced by bleomycin (BLM) was generated to assess the effects of Ncl-Lips and the mechanisms of reversing fibrosis in vivo. Moreover, cell models treated with transforming growth factor β1 (TGFβ1) were used to investigate the mechanism through which Ncl-Lips inhibit fibrosis in vitro. These findings demonstrated that Ncl-Lips could alleviate fibrosis, consequently reversing the changes in the levels of the associated marker. Moreover, the results of the tissue distribution experiment showed that Ncl-Lips had aggregated in the lung. Additionally, Ncl-Lips improved the immune microenvironment in pulmonary fibrosis induced by BLM. Furthermore, Ncl-Lips suppressed the TGFβ1-induced activation of fibroblasts and epithelial−mesenchymal transition (EMT) in epithelial cells. Based on these results, we demonstrated that Ncl-Lips is an efficient strategy for reversing pulmonary fibrosis via drug-delivery.

Repositioning of ezetimibe for the treatment of idiopathic pulmonary fibrosis.

We previously identified ezetimibe, an inhibitor of Niemann-Pick C1-like intracellular cholesterol transporter 1 and European Medicines Agency-approved lipid-lowering agent, as a potent autophagy activator. However, its efficacy against pulmonary fibrosis has not yet been evaluated. This study aimed to determine whether ezetimibe has therapeutic potential against idiopathic pulmonary fibrosis. Primary lung fibroblasts isolated from both humans and mice were employed for mechanistic in vitro experiments. mRNA sequencing of human lung fibroblasts and gene set enrichment analysis were performed to explore the therapeutic mechanism of ezetimibe. A bleomycin-induced pulmonary fibrosis mouse model was used to examine in vivo efficacy of the drug. Tandem fluorescent-tagged microtubule-associated protein 1 light chain 3 transgenic mice were used to measure autophagic flux. Finally, the medical records of patients with idiopathic pulmonary fibrosis from three different hospitals were retrospectively reviewed, and analyses on survival and lung function were conducted to determine the benefits of ezetimibe. Ezetimibe inhibited myofibroblast differentiation by restoring the mechanistic target of rapamycin complex 1-autophagy axis with fine control of intracellular cholesterol distribution. Serum response factor, a potential autophagic substrate, was identified as a primary downstream effector in this process. Similarly, ezetimibe ameliorated bleomycin-induced pulmonary fibrosis in mice by inhibiting mechanistic target of rapamycin complex 1 activity and increasing autophagic flux, as observed in mouse lung samples. Patients with idiopathic pulmonary fibrosis who regularly used ezetimibe showed decreased rates of all-cause mortality and lung function decline. In conclusion, our study presents ezetimibe as a potential novel therapeutic for idiopathic pulmonary fibrosis.

High S100A9 level predicts poor survival, and the S100A9 inhibitor paquinimod is a candidate for treating idiopathic pulmonary fibrosis

BackgroundS100A9 is a damage-associated molecular pattern protein that may play an important role in the inflammatory response and fibrotic processes. Paquinimod is an immunomodulatory compound that prevents S100A9 activity. Its...

Platycodin D improves pulmonary fibrosis in mice by down-regulating TRPC6 expression and reducing ROS production in lung fibroblasts

To assess the effect of platycodin D (PD) for alleviating pulmonary fibrosis in mice and explore the underlying mechanism. C57BL/6J mouse models of pulmonary fibrosis induced by bleomycin injection into the airway were treated with daily intragastric administration of 10 mg/kg PD for 28 days. The changes of pulmonary fibrosis and the expression and distribution of transient receptor potential cation channel subfamily C member 6 (TRPC6) were evaluated with immunohistochemistry, HE staining and Sirius Red staining. Western blotting was used to detect α-SMA expression in the lung tissues of the mice. Primary cultures of mouse lung fibroblasts were pretreated with PD (2.5, 5.0, and 10 μmol/L) or larixyl acetate (LA; 10 μmol/L) before exposure to 10 ng/mL transforming growth factor-β1 (TGF-β1), and the changes in cell survival rate, expressions of collagen Ⅰ, α-SMA and TRPC6, reactive oxygen species (ROS) production, mitochondrial membrane potential, and cell proliferation capacity were assessed. Network pharmacology analysis was performed to explore the mechanism by which PD alleviated pulmonary fibrosis. PD treatment significantly alleviated pulmonary fibrosis and reduced α-SMA expression in BLM-induced mouse models (P<0.05). In TGF-β1-induced primary mouse lung fibroblasts, PD effectively inhibited the cell proliferation, reduced ROS production (P<0.0001), rescued the reduction of mitochondrial membrane potential (P<0.001), and inhibited the expressions of α-SMA and collagen Ⅰ (P<0.05). Network pharmacology analysis suggested that TRPC6 mediated the effect of PD for alleviating pulmonary fibrosis. Immunohistochemistry showed that PD significantly reduced TRPC6 expression in the lung tissues of BLM-induced mice. In primary mouse lung fibroblasts, PD significantly inhibited TGF-β1-induced TRPC6 expression (P<0.05), and LA treatment obviously lowered the expression levels of TRPC6, α-SMA and collagenⅠ (P<0.05). PD alleviated pulmonary fibrosis in mice possibly by down-regulating TRPC6 and reducing ROS production.

Alpinetin ameliorates bleomycin-induced pulmonary fibrosis by repressing fibroblast differentiation and proliferation

ObjectiveIdiopathic pulmonary fibrosis (IPF) is a progressive and irreversible interstitial lung disease with a poor prognosis. Alpinetin (ALP), derived from Alpinia katsumadai Hayata, has shown potential as a therapeutic measure of various diseases. However, the utilization of ALP in managing pulmonary fibrosis and its underlying mechanisms are still not fully understood. MethodsA well-established mouse model of pulmonary fibrosis induced by bleomycin (BLM) was used in this study. The antifibrotic effects of ALP on histopathologic manifestations and expression levels of fibrotic markers were examined. Subsequently, the impact of ALP on fibroblast differentiation, proliferation, apoptosis, and associated signaling pathways was investigated to elucidate the underlying mechanisms. ResultsIn the present study, we observed that ALP effectively mitigated BLM-induced pulmonary fibrosis in mice, as evidenced by histopathological manifestations and the expression levels of fibrotic markers. Furthermore, the in vitro experiments demonstrated that ALP treatment attenuated the ability of fibroblasts to differentiate into myofibroblasts. Mechanically, our findings provided evidence that ALP suppressed fibroblast-to-myofibroblast differentiation by repressing TGF-β/ALK5/Smad signaling pathway. ALP was found to possess the capability of inhibiting fibroblast proliferation and promoting apoptosis of fibroblasts induced by TGF-β. ConclusionIn general, ALP may exert therapeutic effects on pulmonary fibrosis by modulating the differentiation, proliferation, and apoptosis of fibroblasts. Although its safety has been demonstrated in mice, further studies are required to investigate the efficacy of ALP in treatment of patients with IPF.

Leech extract alleviates idiopathic pulmonary fibrosis by TGF-β1/Smad3 signaling pathway

Ethnopharmacological relevanceLeech, as a traditional Chinese medicine for the treatment of blood circulation and blood stasis, was also widely used to cure pulmonary fibrosis in China. In clinical practice, some traditional Chinese medicine preparation such as Shui Zhi Xuan Bi Hua Xian Tang and Shui Zhi Tong Luo Capsule composed of leech, could improve the clinical symptoms and pulmonary function in patients with idiopathic pulmonary fibrosis (IPF). However, the material basis of the leech in the treatment of IPF were not yet clear. Aim of the studyScreen out the components of leech that have the anti-pulmonary fibrosis effects, and further explore the therapeutic mechanism of the active components. Materials and methodsIn this study, the different molecular weight components of leech extract samples were prepared using the semi-permeable membranes with different pore sizes. The therapeutic effects of the leech extract groups with molecular weight greater than 10 KDa (>10 KDa group), between 3 KDa and 10 KDa (3–10 KDa group), and less than 3 KDa (<3 KDa group) on pulmonary fibrosis were firstly investigated by cell proliferation and cytotoxicity assay (MTT), cell wound healing assay, immunofluorescence staining (IF) and Western blot (WB) assay through the TGF-β1-induced fibroblast cell model. Then bleomycin-induced pulmonary fibrosis (BML-induced PF) mouse model was constructed to investigate the pharmacological activities of the active component group of leech extract in vivo. Pathological changes of the mouse lung were observed by hematoxylin-eosin staining (H&E) and Masson's trichrome staining (Masson). The hydroxyproline (HYP) content of lung tissues was quantified by HYP detection kit. The levels of extracellular matrix-related fibronectin (FN) and collagen type Ⅰ (Collagen Ⅰ), pyruvate kinase M2 (PKM2) monomer and Smad7 protein were determined via WB method. PKM2 and Smad7 protein were further characterized by IF assays. ResultsUsing TGF-β1-induced HFL1 cell line as a PF cell model, the in vitro results demonstrated that the >10 KDa group could significantly inhibited the cell proliferation and migration, downregulated the expression level of cytoskeletal protein vimentin and α-smooth muscle actin (α-SMA), and reduced the deposition of FN and Collagen Ⅰ. In the BML-induced PF mouse model, the >10 KDa group significantly reduced the content of HYP, downregulated the expression levels of FN and Collagen Ⅰ in lung tissues, and delayed the pathological changes of lung tissue structure. The results of WB and IF assays further indicated that the >10 KDa group could up-regulate the expression level of PKM2 monomer and Smad7 protein in the cellular level, thereby delaying the progression of pulmonary fibrosis. ConclusionsOur study revealed that the >10 KDa group was the main material basis of the leech extract that inhibited pulmonary fibrosis through TGF-β1/Smad3 signaling pathway.

Characterization of transient and progressive pulmonary fibrosis by spatially correlated phase contrast microCT, classical histopathology and atomic force microscopy

Pulmonary fibrosis (PF) is a severe and progressive condition in which the lung becomes scarred over time resulting in pulmonary function impairment. Classical histopathology remains an important tool for micro-structural tissue assessment in the diagnosis of PF. A novel workflow based on spatial correlated propagation-based phase-contrast micro computed tomography (PBI-microCT), atomic force microscopy (AFM) and histopathology was developed and applied to two different preclinical mouse models of PF - the commonly used and well characterized Bleomycin-induced PF and a novel mouse model for progressive PF caused by conditional Nedd4-2 KO. The aim was to integrate structural and mechanical features from hallmarks of fibrotic lung tissue remodeling. PBI-microCT was used to assess structural alteration in whole fixed and paraffin embedded lungs, allowing for identification of fibrotic foci within the 3D context of the entire organ and facilitating targeted microtome sectioning of planes of interest for subsequent histopathology. Subsequently, these sections of interest were subjected to AFM to assess changes in the local tissue stiffness of previously identified structures of interest. 3D whole organ analysis showed clear morphological differences in 3D tissue porosity between transient and progressive PF and control lungs. By integrating the results obtained from targeted AFM analysis, it was possible to discriminate between the Bleomycin model and the novel conditional Nedd4-2 KO model using agglomerative cluster analysis. As our workflow for 3D spatial correlation of PBI, targeted histopathology and subsequent AFM is tailored around the standard procedure of formalin-fixed paraffin-embedded (FFPE) tissue specimens, it may be a powerful tool for the comprehensive tissue assessment beyond the scope of PF and preclinical research.