Intracellular hydroxyproline imprinting following resolution of bleomycin-induced pulmonary fibrosis

Spatially Resolved Metabolomics Reveals Metabolic Heterogeneity Among Pulmonary Fibrosis

Pulmonary fibrosis (PF) is a chronic and progressive lung disease with fatal consequences. The study of PF is challenging due to the complex mechanism involved, the need to understand the heterogeneity and spatial organization within lung tissues. In this study, we investigate the metabolic heterogeneity between two forms of lung fibrosis: idiopathic pulmonary fibrosis (IPF) and silicosis, using advanced spatially-resolved metabolomics techniques. Employing high-resolution mass spectrometry imaging, we spatially mapped and identified over 260 metabolites in lung tissue sections from mouse models of IPF and silicosis. Histological analysis confirmed fibrosis in both models, with distinct pathological features: alveolar destruction and collagen deposition in IPF, and nodule formation in silicosis. Metabolomic analysis revealed significant differences between IPF and silicosis in key metabolic pathways, including phospholipid metabolism, purine/pyrimidine metabolism, and the TCA cycle. Notably, phosphocholine was elevated in silicosis but reduced in IPF, while carnitine levels decreased in both conditions. Additionally, glycolytic activity was increased in both models, but TCA cycle intermediates showed opposing trends. These findings highlight the spatial metabolic heterogeneity of PF and suggest potential metabolic targets for therapeutic intervention. Further investigation into the regulatory mechanisms behind these metabolic shifts may open new avenues for fibrosis treatment.

Targeted Collagen Degradation by an MRI Probe Facilitates siRNA Delivery for Sequential Theranostics in Pulmonary Fibrosis

Pulmonary fibrosis (PF) is characterized by dense collagen and mucus barriers that significantly limit drug delivery to the lungs. Clearing the collagen barrier can enhance drug delivery efficiency. Nevertheless, the heterogeneity of collagen states among patients poses a challenge. Therefore, real-time monitoring of the collagen clearance status is essential for PF personalized therapy. Herein, sequential theranostic platforms are proposed for collagen targeting and magnetic resonance imaging (MRI) monitoring to guide small interfering RNA (siRNA) delivery. First, for collagen barrier targeting-degrading, collagenase is conjugated with a collagen-targeting peptide capable of chelating the MRI contrast agent Gd(III), forming Col I T-D. This allows real-time, noninvasive MRI monitoring of the dynamic collagen clearance process. Second, guided by MRI, the zwitterionic polymer-based siRNA vectors (siTGF-β1@TZ) with mucus-penetrating and fibroblast-targeting capabilities are inhaled under an optimal state of collagen barrier. The sequential application of Col I T-D and siTGF-β1@TZ demonstrates significant lesion enrichment and therapeutic efficacy in PF treatment. Collectively, this study provides a novel perspective on dynamically monitoring collagen clearance status and guiding the sequential delivery of siRNA, offering a promising strategy for personalized PF therapy.

SIRT3/6/7: promising therapeutic targets for pulmonary fibrosis

Pulmonary fibrosis is a chronic progressive fibrosing interstitial lung disease of unknown cause, characterized by excessive deposition of extracellular matrix, leading to irreversible decline in lung function and ultimately death due to respiratory failure and multiple complications. The Sirtuin family is a group of nicotinamide adenine dinucleotide (NAD+) -dependent histone deacetylases, including SIRT1 to SIRT7. They are involved in various biological processes such as protein synthesis, metabolism, cell stress, inflammation, aging and fibrosis through deacetylation. This article reviews the complex molecular mechanisms of the poorly studied SIRT3, SIRT6, and SIRT7 subtypes in lung fibrosis and the latest research progress in targeting them to treat lung fibrosis.

Integrated network pharmacological analysis and multi-omics techniques to reveal the mechanism of polydatin in the treatment of silicosis via gut-lung axis

Silicosis is a pulmonary disease characterized by inflammation and progressive fibrosis. Previous studies have shown that polydatin (PD) has potential biological activity in key signaling pathways regulating inflammation and apoptosis. To investigate the effect of PD on rats with silicosis, this study used network pharmacology and molecular docking methods to determine the target of PD treatment for silicosis. The therapeutic effect of PD on silicosis was confirmed by measuring the lung injury score, hydroxyproline content, and mRNA expression levels of key targets. In addition, metagenomic sequencing and gas chromatography-mass spectrometry were used to determine the gut microbiota composition and targeted metabolomics analysis, respectively. The results showed that PD could inhibit the expression of inflammation-related indexes and apoptosis-related indexes at protein and mRNA levels. PD also regulates the diversity of the intestinal flora and the content of short-chain fatty acids. In conclusion, the current data suggest that PD has a protective effect against silica-induced lung injury and plays a protective role in regulating intestinal flora diversity and short-chain fatty acid levels through the gut-lung axis.

In silico, in vitro, and in vivo assessment of chitosan-diltiazem nanoparticles against pulmonary fibrosis

AIMS

Diltiazem (DIL), a calcium channel blocker, has demonstrated potential ininhibiting fibrosis-related processes, including TGF-β activation, collagen production, and epithelial-mesenchymal transition, making it a promising candidate for idiopathic pulmonary fibrosis (IPF). This study evaluates the anti-fibrotic efficacy of DIL-loaded chitosan (DIL-CHT) and trimethyl chitosan (DIL-TMC) nanoparticles through molecular and experimental approaches.

METHODS

DIL-CHT and DIL-TMC nanoformulations were developed and analyzed particle size, ζ-potential, entrapment efficiency, and in vitro release. Antifibrotic efficacy in bleomycin (BLM)-induced IPF rat model, was tested at subtherapeutic doses (3 mg/kg/day, i.t.) and DIL alone (10 mg/kg/day, p.o.). DFT (B3LYP/6-31 G**) optimization and molecular docking were conducted to assess electronic properties and interactions among CHT, TMC, and DIL.

RESULTS

DIL-TMC and DIL-CHT nanoparticles were 175.6 nm and 267.8 nm, with entrapment efficiencies of 81.72% and 66.0%, respectively; TMC showed a superior 24-hour sustained release. TMC's larger HOMO-LUMO gap (ΔE = -0.260 eV vs. -0.253 eV for CHT) suggests greater stability, supporting its enhanced interaction with DIL. TMC nanoparticles significantly reduced BLM-induced IPF symptoms, i.e. BLM induced increased lung index, hydroxyproline accumulation, oxidative stress in lung tissue, and blood pressure.

CONCLUSIONS

These findings indicate the strong therapeutic potential of DIL-TMC for IPF with minimal cardiovascular side effects.

Iguratimod improves bleomycin-induced pulmonary inflammation and fibrosis by regulating macrophage polarization through inhibiting the TLR4/NF-κB pathway

Introduction

Pulmonary fibrosis (PF) is a fatal pathological subtype of interstitial lung disease, frequently manifests as a pulmonary complication of connective tissue disease. Iguratimod (IGU) is a new class of anti-rheumatic drugs used in the treatment of rheumatoid arthritis (RA). Studies have reported that RA patients treated with IGU have better lung function, and IGU effectively ameliorates PF. However, the mechanism by which IGU improves PF is still unclear. This study aims to elucidate the therapeutic efficacy and mechanisms of IGU in PF through in vivo and in vitro investigations, so as to provide a new treatment method for PF.

Methods

In our research, bleomycin (BLM)-induced PF of mice were used to observe the therapeutic effect of different concentrations of IGU. And the effects of IGU on macrophage polarization and activation pathway TLR4/NF-κB in lung tissue were analyzed. In addition, Raw264.7 macrophages were induced to M1 and M2 polarization in vitro, and the effects of IGU on Raw264.7 macrophage polarization and related pathways were observed.

Results

In our study, database analysis suggested that macrophage polarization-relative genes and pathways as well as TLR4 activation played important roles in BLM-induced PF in mice. Besides, we found that IGU effectively ameliorated BLM-induced PF and epithelial-mesenchymal transition in mice, and inhibited the polarization of M1/M2 macrophages at different stages of PF. Moreover, In vitro studies further demonstrated that IGU suppressed M1 polarization of Raw264.7 and its activation pathway TLR4/NF-κB.

Discussion

In summary, IGU inhibits the activation of macrophages and M1 polarization through inhibiting the TLR4/NF-κB pathway, thereby improving BLM-induced pulmonary inflammation and fibrosis in mice. It is suggested that IGU may be a new therapeutic option for interstitial pulmonary fibrosis.

Targeted imaging of pulmonary fibrosis by a cyclic peptide LyP-1

Pulmonary fibrosis (PF) is an interstitial chronic lung disease characterized by interstitial inflammation and extracellular matrix deposition, resulting in progressive lung dysfunction and ultimate respiratory failure. However, lacking of precise and noninvasive tracers for fibrotic lesions limits timely diagnosis and treatment. Here, we identified LyP-1, a cyclic peptide, as a specific and sensitive tracer for PF detection using PET/CT imaging. FITC-LyP-1 selectively recognized fibrotic regions in bleomycin-induced PF mice, indicating its targeting capability. The colocalization of FITC-LyP-1 with extracellular collagen I within the fibrotic lesions validated its specificity, and further analysis revealed several potential target molecules. In the in vivo application studies, radiolabeled [68Ga]Ga-LyP-1 showed significantly increased lung uptake in PF mice, specifically enriching fibrotic regions on PET/CT imaging. Notably, compared to CT imaging that showed increased mean lung density throughout the phases after bleomycin-administration, lung uptake of [68Ga]Ga-LyP-1 was only increased in the later phase, indicating that LyP-1 recognizes the fibrous changes rather than the inflammatory cells in vivo. These results suggest that the new radiotracer [68Ga]Ga-LyP-1 specifically detects the extracellular matrix in fibrotic lungs. LyP-1 shows promise as a noninvasive tracer for assessing human pulmonary fibrosis, offering potential for improved diagnostic accuracy and timely intervention.

T1/T2 mapping as a non-invasive method for evaluating liver fibrosis based on correlation of biomarkers: a preclinical study

BACKGROUND

Given the inherent limitations of invasive biopsy and the insufficient accuracy of liver-related serum biomarkers, there is an urgent need for the development of reliable, non-invasive imaging techniques for the diagnosis of liver fibrosis. This study aims to investigate the correlation between magnetic resonance imaging (MRI) T1/T2 mapping sequences and biomarkers of collagen deposition and ongoing systemic inflammation, and to evaluate the potential of T1/T2 mapping as a non-invasive method for the accurate diagnosis of liver fibrosis.

METHODS

A mouse model of carbon tetrachloride (CCl4)-induced liver fibrosis was established and T1/T2 mapping were performed at different weeks of treatment. The histopathological analysis, collagen quantification, and inflammatory factors measurements (IL-1, IL-6, TNF-α) were conducted to correlate MRI parameters with collagen deposition and inflammation. Statistical analysis was performed using IBM SPSS Statistics (version 22.0, Chicago, IL, USA) and Origin 2018 (OriginLab Corporation, Northampton, MA, USA).

RESULTS

The principal findings indicated that T1 and T2 values exhibited a progressive increase with the severity of fibrosis, demonstrating a positive correlation with collagen deposition and inflammatory factors, especially the hydroxyproline content (r = 0.880, P < 0.001). The HYP content exhibited a progressive increase with advancing fibrosis stages (ρ = 0.914, P < 0.001). Similarly, T1 values increased significantly across fibrosis stage(ρ = 0.854, P < 0.001). Statistical comparison of these coefficients revealed no significant difference (Z = 1.031, P = 0.303). ROC curve analysis showed that T1 mapping was more accurate than T2 mapping in detecting collagen deposition and inflammation.

CONCLUSIONS

This study highlighted the potential of T1/T2 mapping as non-invasive and quantitative biomarkers for diagnosing and staging liver fibrosis, providing new insights into the onset and progression of liver fibrosis.

Safety, Efficacy and Bio-Distribution Analysis of Exosomes Derived From Human Umbilical Cord Mesenchymal Stem Cells for Effective Treatment of Bronchopulmonary Dysplasia by Intranasal Administration in Mice Model

Purpose

Exosomes (Exos) derived from human umbilical cord mesenchymal stem cells (hUC-MSCs) hold great potential for treating bronchopulmonary dysplasia (BPD); however, safety concerns and effects of intranasal administration remain unexplored. This study aimed to explore the safety of hUC-MSCs and Exos and to investigate the efficacy and bio-distribution of repeated intranasal Exos administration in neonatal BPD models.

Methods

Characteristics of hUC-MSCs and Exos were analyzed. A subcutaneous tumor formation assay using a single dose of hUC-MSCs or Exos was conducted in Crl:NU-Foxn1nu mice. Vital signs, biochemical indices, pathological alterations, and 18F-FDG microPET/CT analysis were examined. Pulmonary pathology, three-dimensional reconstructions, ultrastructural structures, in vivo and ex vivo bio-distribution imaging analyses, enzyme-linked immunoassay assays, and reverse transcription-quantitative polymerase chain reaction analyses of lung tissues were all documented following intranasal Exos administration.

Results

Characteristics of hUC-MSCs and Exos satisfied specifications. Crl:NU-Foxn1nu mice did not exhibit overt toxicity or carcinogenicity following a single dose of hUC-MSCs or Exos after 60 days of observation. Repeated intranasal Exos administration effectively alleviated pathological injuries, restored pulmonary ventilation in three-dimensional reconstruction, and recovered endothelial cell layer integrity in ultrastructural analysis. Exos steadily accumulated in lung tissues from postnatal day 1 to 14. Exos also interrupted the epithelial-mesenchymal transition and inflammation reactions in BPD models.

Conclusion

As a nanoscale, non-cellular therapy, intranasal administration of Exos was an effective, noninvasive treatment for BPD. This approach was free from toxic, tumorigenic risks and repaired alveolar damage while interrupting epithelial-mesenchymal transition and inflammation in neonatal mice with BPD.

7-Hydroxy-3-(4'-methoxyphenyl) coumarin (C12) attenuates bleomycin-induced acute lung injury and fibrosis through activation of SIRT3

Silent mating-type information regulation 2 homology 3 (SIRT3) is a member of the sirtuins family expressed in mitochondria performs deacetylation of metabolic enzymes and promotes longevity. 7-hydroxy-3-(4'-methoxyphenyl) coumarin (C12) is a small molecule first ever known for its direct activation of SIRT3. SIRT3 performs its function by balancing the redox system by activating manganese superoxide dismutase (MnSOD) and 8-Oxoguanine glycosylase (OGG1). For the first time, we reported that activation of SIRT3 by C12 attenuated bleomycin (BLM)-)-induced acute lung injury and pulmonary fibrosis. C12 prevented the oxidative stress and injury caused by BLM in alveolar epithelial cells (BEAS-2B) in in vitro and inhibited the fibrosis in transforming growth factor-beta (TGF-β) induced fibrosis in fibroblasts (MRC-5). Additionally, activation of SIRT3 by C12 in vivo mice model alleviated BLM-induced inflammation, collagen accumulation, cellular infiltration, and restoration of alveolar architecture by inhibiting TGF-β, smooth muscle actin (α-SMA), collagen-1A, collagen-3A, and mesenchymal markers. The protective effect of C12 was through activation of MnSOD and OGG1 in both in vitro and in vivo models suggesting C12 can be a potent SIRT3 activator and helps to treat fibrotic-related diseases.

Inhalable siRNA Targeting IL-11 Nanoparticles Significantly Inhibit Bleomycin-Induced Pulmonary Fibrosis

For idiopathic pulmonary fibrosis (IPF), interleukin 11 (IL-11) is a pivotal cytokine that stimulates the transformation of fibroblasts into myofibroblasts, thus accelerating the progression of pulmonary fibrosis. Here, we develop an innovative inhalable small interfering RNA (siRNA) delivery system termed PEI-GBZA, which demonstrates impressive efficiency in loading siIL-11 targeting IL-11 (siIL-11) and substantially suppresses the differentiation of fibroblasts into myofibroblasts and epithelial-mesenchymal transition (EMT), reduces neutrophil and macrophage recruitment, and ultimately relieves the established fibrotic lesions in the IPF model. PEI-GBZA is prepared by modifying low-molecular-weight polyethylenimine (PEI) with 4-guanidinobenzoic acid (GBZA). The resulting PEI-GBZA may effectively encapsulate siIL-11 through a variety of interactions such as hydrophobic, hydrogen bonding, and electrostatic interactions, creating stable carrier/siIL-11 nanoparticles (PEI-GBZA/siIL-11 NPs). Upon inhalation, PEI-GBZA/siIL-11 NPs demonstrate effective retention in fibrotic lesions, leading to a marked mitigation of disease progression in a bleomycin-induced pulmonary fibrosis model. Impressively, this inhalation therapy exhibits negligible systemic toxicity. This work provides a universal and noninvasive RNA therapeutic delivery platform that holds significant promise for respiratory diseases. The potential for clinical application of this platform is substantial, offering a frontier for the treatment of IPF and potentially other pulmonary disorders.

Maternal nutrition and offspring lung health: sex-specific pathway modulation in fibrosis, metabolism, and immunity

Background

Maternal nutrition profoundly influences offspring health, impacting both prenatal and early postnatal development. Previous studies have demonstrated that maternal dietary habits can affect key developmental pathways in the offsprings, including those related to lung function and disease susceptibility. However, the sex-specific impact of a maternal high-salt diet (HSD) on offspring lung injury remains poorly understood.

Objective

This study aimed to investigate the sex-specific effects of maternal HSD on lung injury in mouse offsprings, focusing on pathways related to fibrosis, metabolism, immunity, and apoptosis.

Design

Pregnant C57BL/6J mice were subjected to either normal or HSD conditions during gestation. Lung tissues from the male and female offsprings were analyzed using high-throughput RNA sequencing and bioinformatics tools to examine transcriptomic changes. Wet-lab validation, including Masson trichrome staining, immunofluorescence for α-SMA, and qRT-PCR for fibrotic markers (α-SMA, collagen I, Fn1, and TGF-β), was conducted to confirm fibrosis and other injury markers. Lung structure and weight were also evaluated to assess physical alterations due to maternal diet.

Results

Maternal HSD significantly altered lung transcriptomes in a sex-specific manner. Male offsprings showed increased susceptibility to fibrosis, as confirmed by histological and molecular analyses, including elevated expression of α-SMA, collagen I, Fn1, and TGF-β. In contrast, female offsprings exhibited distinct changes in metabolic and immune pathways. These findings highlight the differential regulation of pulmonary injury mechanisms between male and female offsprings exposed to HSD.

Conclusions

Maternal HSD induces sex-specific lung injury in offsprings by disrupting critical pathways involved in fibrosis, metabolism, immunity, and apoptosis. The combination of transcriptomic and orthogonal data underscores the need for balanced maternal nutrition during pregnancy to promote long-term respiratory health in offsprings. These results provide new insights into the sex-specific vulnerabilities to lung disease arising from maternal diet.

Dietary Antrodia cinnamomea Polysaccharide Intervention Modulates Clinical Symptoms by Regulating Ovarian Metabolites and Restructuring the Intestinal Microbiota in Rats with Letrozole-Induced PCOS

Polycystic ovary syndrome (PCOS) is a prevalent endocrine and metabolic disorder. This study investigated the mitigating effects of the Antrodia cinnamomea polysaccharide (ACP) on a letrozole-induced PCOS rat model. Results demonstrated that ACP reduced obesity and ameliorated dyslipidemia in PCOS rats. Moreover, ACP restored estrous cycle regularity, suppressed polycystic ovarian changes, and regulated serum levels of sex hormones, SOD, and MDA. Furthermore, ACP increased the α-diversity and modulated the abundance of phyla (Bacteroidetes, Firmicutes, and Verrucomicrobia) and genera (Lactobacillus, Helicobacter, Akkermansia, Oscillospira, Coprococcus, Roseburia, Blautia, and Allobaculum) in the gut microbiota. ACP also restored compromised intestinal barriers by upregulating the expression of ZO1, Occludin, Claudin1, and Claudin7 in the colon. ACP mitigated ovarian fibrosis by preventing activation of the NLRP3 inflammasome, decreasing the expression of fibrotic markers (TGF-β1, collagen-I, α-SMA, and CTGF), and regulating four ovarian fibrosis-associated metabolomics pathways. Generally, dietary ACP effectively ameliorated clinical symptoms and inhibited ovarian fibrosis in PCOS rats.

RNA-seq analysis and in vivo experiments identified the protective effect of kaempferol on idiopathic pulmonary fibrosis by regulating the PPARG/TNC signaling pathway to reduce ECM deposition

Idiopathic pulmonary fibrosis (IPF) is a chronic age-related lung disease with a high mortality rate. Kaempferol (KMP), an active ingredient in common plants and foods with anti-inflammatory, antioxidant and immunomodulatory properties, has been shown to be effective against fibrotic diseases. However, the molecular mechanisms underlying the treatment of IPF with KMP remain unclear. Therefore, IPF mice were established by intratracheal instillation of bleomycin (BLM) to explore the efficacy and underlying mechanism of KMP in the treatment of IPF. We found that KMP improved the body weight changes of BLM-induced IPF mice, alleviated inflammatory infiltration and collagen deposition, and decreased the expression levels of hydroxyproline, α-SMA, Col3a1, Mmp2, Timp1, Vim, Fn, TNF-α, TGF-β1, IL-6 and IL-8, while up-regulating the expression E-cadherin in lung tissues. The transcriptomic results showed that KMP may exert therapeutic effects against IPF by regulating the PPARG/TNC signaling pathway to reduce extracellular matrix (ECM) deposition. Interestingly, ROC curve analysis suggested that TNC and PPARG had good diagnostic performance for IPF, and TF prediction revealed that PPARG is an important upstream gene regulating TNC, and the IF experiment confirmed the co-localization of TNC and PPARG. Molecular docking showed that KMP bound well to PPARG and TNC, and IF results revealed that KMP significantly reduced the interaction between PPARG and TNC. Furthermore, RT-PCR, WB, IHC and IF experiments confirmed that KMP elevated the expression of PPARG and inhibited the expression of TNC, thus inhibiting the ECM-receptor interaction pathway and ultimately serving as a therapeutic treatment for IPF mice. These findings revealed that KMP reduced inflammatory infiltration and collagen deposition in the lungs of IPF mice and that the PPARG/TNC signaling pathway may be an important mechanism for the treatment of IPF with KMP, which provides a new perspective for the development of therapeutic approaches for IPF.

[18F]AlF-CBP imaging of type I collagen for non-invasive monitoring of pulmonary fibrosis in preclinical models

PURPOSE

Pulmonary fibrosis is an irreversible scar-forming condition for which there is a lack of non-invasive and specific methods for monitoring its progression and therapy efficacy. However, the disease is known to be accompanied by collagen accumulation. Here, we developed a novel positron emission tomography (PET) probe targeting type I collagen to evaluate its utility for the non-invasive assessment of pulmonary fibrosis.

METHODS

We designed a 18F-labeled PET probe ([18F]AlF-CBP) to target type I collagen and evaluated its binding affinity, specificity and stability in vitro. PET with [18F]AlF-CBP, CT, histopathology, immunofluorescence, and biochemical indice were performed to assess and quantify type I collagen levels and pulmonary fibrosis progression and treatment in murine models. Dynamic PET/CT studies of [18F]AlF-CBP were conducted to assess lung fibrosis in non-human primate models.

RESULTS

[18F]AlF-CBP was successfully prepared, and in vitro and in vivo tests showed high stability (> 95%) and type I collagen specificity (IC50 = 0.36 µM). The lungs of the fibrotic murine model showed more elevated probe uptake and retention compared to the control group, and there was a positive correlation between the radioactivity uptake signals and the degree of fibrosis (CT: R2 = 0.89, P < 0.0001; hydroxyproline levels: R2 = 0.89, P < 0.0001). PET signals also correlated well with mean lung density in non-human primate models of pulmonary fibrosis (R2 = 0.84, P < 0.0001).

CONCLUSION

[18F]AlF-CBP PET imaging is a promising non-invasive method for specific monitoring of lung fibrosis progression and therapy efficacy.

Inhalation of itraconazole mitigates bleomycin-induced lung fibrosis via regulating SPP1 and C3 signaling pathway pivotal in the interaction between phagocytic macrophages and diseased fibroblasts

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) stands as a significant contributor to global mortality rates. Presently, there exists a dearth of effective anti-fibrotic treatments for this condition. While itraconazole (ITR) has exhibited potential in mitigating pulmonary fibrosis, its oral administration is hampered by unfavorable pharmacokinetics, which elevate the risk of adverse reactions, thus limiting its clinical utility.

METHODS

An inhalable formulation of ITR were engineered which aimed at enhancing its pulmonary dispersion. First, pharmacokinetics were conducted to investigate the blood concentration and tissue residue of ITR after inhalation administration. In addition, bleomycin induced mouse pulmonary fibrosis model was used to compare the therapeutic effects of ITR administered by inhalation and intragastric administration. Finally, single-cell RNA sequencing (scRNAseq) was used to explore the mechanism of ITR inhalation administration.

RESULTS

We found that a large amount of drugs accumulated in the lung tissue for a long time after inhalation administration, thus maximizing the therapeutic effect of drugs. Inhalation of ITR daily at for 21 days significantly attenuated bleomycin-induced lung fibrosis and inflammation in murine models. Additionally, our findings revealed that ITR inhalation diminished the proportion of diseased fibroblasts while promoting reparative fibroblast populations in the murine model. Furthermore, it effectively reversed the proportion of activated phagocytic macrophages. Mechanistically, ITR inhalation exerted its effects by regulating SPP1 and C3 signaling pathway pivotal in the interaction between phagocytic macrophages and diseased fibroblasts.

CONCLUSIONS

These insights into the molecular mechanisms underlying ITR's therapeutic effects on IPF underscore the favorable pharmacokinetic profile conferred by inhalation, thus presenting a promising formulation poised for clinical translation.

Soybean Extract Ameliorates Lung Injury induced by Uranium Inhalation: An integrated strategy of network pharmacology, metabolomics, and transcriptomics

AIM

This study aimed to evaluate the protective effect of soybean extract (SE) against uranium-induced lung injury in rats.

MATERIALS AND METHODS

A rat lung injury model was established through nebulized inhalation of uranyl nitrate. Pretreatment with SE or sterile water (control group) by gavage for seven days before uranium exposure and until the experiment endpoints. The levels of uranium in lung tissues were detected by ICP-MS. Paraffin embedding-based hematoxylin & eosin staining and Masson's staining for the lung tissue were performed to observe the histopathological imaging features. A public database was utilized to analyze the network pharmacological association between SE and lung injury. The expression levels of proteins indicating fibrosis were measured by enzyme-linked immunosorbent assay. RNA-seq transcriptomic and LC-MS/MS targeted metabolomics were conducted in lung tissues.

RESULTS

Uranium levels in the lung tissues were lower in SE-pretreated rats than in the uranium-treated group. Inflammatory cell infiltration and the deposition of extracellular matrix were attenuated, and the levels of alpha-smooth muscle actin, transforming growth factor beta1, and hydroxyproline decreased in SE-pretreated rats compared to the uranium-treated group. Active ingredients of SE were related to inflammation, oxidative stress, and drug metabolism. A total of 67 differentially expressed genes and 39 differential metabolites were identified in the SE-pretreated group compared to the uranium-treated group, focusing on the drug metabolism-cytochrome P450, glutathione metabolism, IL-17 signaling pathway, complement, and coagulation cascades.

CONCLUSIONS

These findings suggest that SE may ameliorate uranium-induced pulmonary inflammation and fibrosis by regulating glutathione metabolism, chronic inflammation, and immune regulation.

Correlations between coagulation abnormalities and inflammatory markers in trauma-induced coagulopathy

Introduction

In multiple trauma patients, the occurrence of trauma-induced coagulopathy (TIC) is closely associated with tissue damage and coagulation function abnormalities in the pathophysiological process.

Methods

This study established a multiple trauma and shock model in Sprague-Dawley (SD) rats and comprehensively utilized histological staining and radiographic imaging techniques to observe injuries in the intestine, liver, skeletal muscles, and bones. Monitoring activated partial thromboplastin time (APTT), platelet (PLT) count, respiratory rate, blood pressure, and other physiological indicators revealed time-dependent alterations in coagulation function and physiological indicators. Enzyme-linked immunosorbent assay (ELISA) measurements of inflammatory factors Tumor Necrosis Factor-alpha (TNF-α), Interleukin-6 (IL-6) and vascular endothelial injury marker (Syndecan-1) were also conducted.

Results

Experimental results demonstrated significant changes in tissue structure after multiple traumas, although widespread necrosis or hemorrhagic lesions were not observed. There were time-dependent alterations in coagulation function and physiological indicators. ELISA measurements showed a strong positive correlation between the significant decrease in PLT count and the increase in TNF-α and IL-6 concentrations.

Discussion

The study provides crucial information for the early diagnosis and treatment of TIC. The findings suggest that structured monitoring of coagulation and inflammatory indicators can help in understanding the pathophysiological changes and aid in the management of TIC in multiple trauma patients.

Delineating, Imaging, and Assessing Pulmonary Fibrosis Remodeling via Collagen Hybridization

Idiopathic pulmonary fibrosis (IPF) is a progressive, life-threatening disease with no early detection, few treatments, and dismal outcomes. Although collagen overdeposition is a hallmark of lung fibrosis, current research mostly focuses on the cellular aspect, leaving collagen, particularly its dynamic remodeling (i.e., degradation and turnover), largely unexplored. Here, using a collagen hybridizing peptide (CHP) that specifically binds unfolded collagen chains, we reveal vast collagen denaturation in human IPF lungs and delineate the spatiotemporal progression of collagen denaturation three-dimensionally within fibrotic lungs in mice. Transcriptomic analyses support that lung collagen denaturation is strongly associated with up-regulated collagen catabolism in mice and patients. We thus show that CHP probing differentiates remodeling responses to antifibrotics and highlights the resolution of established fibrosis by agents up-regulating collagen catabolism. We further develop a radioactive CHP that detects fibrosis in vivo in mice as early as 7 days postlung-injury (Ashcroft score: 2-3) by positron emission tomography (PET) imaging and ex vivo in clinical lung specimens. These findings establish collagen denaturation as a promising marker of fibrotic remodeling for the investigation, diagnosis, and therapeutic development of pulmonary fibrosis.

Chlorquinaldol Alleviates Lung Fibrosis in Mice by Inhibiting Fibroblast Activation through Targeting Methionine Synthase Reductase

Idiopathic pulmonary fibrosis (IPF) is a progressive interstitial lung disease with limited treatment options. Thus, it is essential to investigate potential druggable targets to improve IPF treatment outcomes. By screening a curated library of 201 small molecules, we have identified chlorquinaldol, a known antimicrobial drug, as a potential antifibrotic agent. Functional analyses have demonstrated that chlorquinaldol effectively inhibits the transition of fibroblasts to myofibroblasts in vitro and mitigates bleomycin-induced pulmonary fibrosis in mice. Using a mass spectrometry-based drug affinity responsive target stability strategy, we revealed that chlorquinaldol inhibited fibroblast activation by directly targeting methionine synthase reductase (MTRR). Decreased MTRR expression was associated with IPF patients, and its reduced expression in vitro promoted extracellular matrix deposition. Mechanistically, chlorquinaldol bound to the valine residue (Val-467) in MTRR, activating the MTRR-mediated methionine cycle. This led to increased production of methionine and s-adenosylmethionine, counteracting the fibrotic effect. In conclusion, our findings suggest that chlorquinaldol may serve as a novel antifibrotic medication, with MTRR-mediated methionine metabolism playing a critical role in IPF development. Therefore, targeting MTRR holds promise as a therapeutic strategy for pulmonary fibrosis.

A Pilot HRCT Follow-Up Study to Test the Feasibility of Predictive Efficacy of Serum Periostin in Idiopathic Pulmonary Fibrosis

Background

While serum periostin and Krebs von den Lungen-6 (KL-6) have been acknowledged as independent markers in idiopathic pulmonary fibrosis (IPF) diagnosis, the clinical combinatory potential of these biomarkers combined with high-resolution computed tomography (HRCT) has yet to be fully explored.

Methods

This retrospective study involved 78 participants, comprising 51 UIP-IPF patients and 27 healthy controls. All subjects underwent clinical and laboratory examinations, particularly the detection of periostin and KL-6 using ELISA with innovative HRCT fibrosis score evaluations at admission and discharge during hospitalization in UIP-IPF patients.

Results

In our cohort of patients with IPF, predominantly male, over an average follow-up period of 195.27 days. Serum levels of periostin and KL-6 were significantly elevated in IPF patients compared to healthy controls (*p < 0.05). Post-treatment, KL-6 levels decreased significantly, while periostin levels increased. Notably, periostin exhibited superior prognostic accuracy over KL-6, with a higher AUC of 0.875 than 0.639 in ROC analysis. An increase in periostin levels correlated with disease progression, as evidenced by worsened HRCT fibrotic scores and decreased survival probability. These findings underscore periostin's potential as a reliable biomarker for assessing IPF severity and therapeutic response.

Conclusion

Our findings underscore the preeminence of serum periostin over KL-6 in UIP-IPF diagnosis, particularly when conjoined with HRCT fibrosis score.

Harmine inhibits pulmonary fibrosis through regulating DNA damage repair-related genes and activation of TP53-Gadd45α pathway

BACKGROUND

Harmine has many pharmacological activities and has been found to significantly inhibit the fibrosis of keloid fibroblasts. DNA damage repair (DDR) is essential to prevent fibrosis. This study aimed to investigate the effects of harmine on pulmonary fibrosis and its underlying mechanisms.

METHODS

Bleomycin and TGF-β1 were used to construct pulmonary fibrosis models in vivo and in vitro, then treated with harmine to explore harmine's effects in treating experimental pulmonary fibrosis and its related mechanisms. Then, RNA sequencing was applied to investigate further the crucial DDR-related genes and drug targets of harmine against pulmonary fibrosis. Finally, the expression levels of DDR-related genes were verified by real-time quantitative PCR (RT-qPCR) and western blot.

RESULTS

Our in vivo experiments showed that harmine treatment could improve weight loss and lung function and reduce tissue fibrosis in mice with pulmonary fibrosis. The results confirmed that harmine could inhibit the viability and migration of TGF-β1-induced MRC-5 cells, induce their apoptosis, and suppress the F-actin expression, suggesting that harmine could suppress the phenotypic transition from lung fibroblasts to lung myoblasts. In addition, RNA sequencing identified 1692 differential expressed genes (DEGs), and 10 DDR-related genes were screened as critical DDR-related genes. RT-qPCR and western blotting showed that harmine could down-regulate the expression of CHEK1, ERCC1, ERCC4, POLD1, RAD51, RPA1, TOP1, and TP53, while up-regulate FEN1, H2AX and GADD45α expression.

CONCLUSIONS

Harmine may inhibit pulmonary fibrosis by regulating DDR-related genes and activating the TP53-Gadd45α pathway.

A nitroreductase responsive probe for early diagnosis of pulmonary fibrosis disease

Idiopathic pulmonary fibrosis (IPF) is a serious interstitial lung disease. However, the definitive diagnosis of IPF is impeded by the limited capabilities of current diagnostic methods, which may fail to capture the optimal timing for treatment. The main goal of this study is to determine the feasibility of a nitroreductase (NTR) responsive probe, 18F-NCRP, for early detection and deterioration monitoring of IPF. 18F-NCRP was obtained with high radiochemical purity (>95 %). BLM-injured mice were established by intratracheal instillation with bleomycin (BLM) and characterized through histological analysis. Longitudinal PET/CT imaging, biodistribution study and in vitro autoradiography were performed. The correlations between the uptake of 18F-NCRP and mean lung density (tested by CT), as well as histopathological characteristics were analyzed. In PET imaging study, 18F-NCRP exhibited promising efficacy in monitoring the progression of IPF, which was earlier than CT. The ratio of uptake in BLM-injured lung to control lung increased from 1.4-fold on D15 to 2.2-fold on D22. Biodistribution data showed a significant lung uptake of 18F-NCRP in BLM-injured mice. There was a strong positive correlation between the 18F-NCRP uptake in the BLM-injured lungs and the histopathological characteristics. Given that, 18F-NCRP PET imaging of NTR, a promising biomarker for investigating the underlying pathogenic mechanism of IPF, is attainable as well as desirable, which might lay the foundation for establishing an NTR-targeted imaging evaluation system of IPF.

Wogonin protects against bleomycin-induced mouse pulmonary fibrosis via the inhibition of CDK9/p53-mediated cell senescence

Pulmonary fibrosis (PF) is a fatal interstitial lung disease associated with declining pulmonary function but currently with few effective drugs. Cellular senescence has been implicated in the pathogenesis of PF and could be a potential therapeutic target. Emerging evidence suggests wogonin, the bioactive compound isolated from Scutellaria baicalensis, owns the anti-senescence properties, however, the possible impact of wogonin on PF and the potential mechanisms remain unclear. In this study, a well-established mouse model of PF was utilized which mice were administrated with bleomycin (BLM). Strikingly, wogonin treatment significantly reduced fibrosis deposition in the lung induced by BLM. In vitro, wogonin also suppressed fibrotic markers of cultured epithelial cells stimulated by BLM or hydrogen peroxide. Mechanistic investigation revealed that wogonin attenuated the expressions of DNA damage marker γ-H2AX and senescence-related markers including phosphorylated p53, p21, retinoblastoma protein (pRB), and senescence-associated β-galactosidase (SA-β-gal). Moreover, wogonin, as a direct and selective inhibitor of cyclin-dependent kinase 9 (CDK9), exhibited anti-fibrotic capacity by inhibiting CDK9 and p53/p21 signalling. In conclusion, wogonin protects against BLM-induced PF in mice through the inhibition of cell senescence via the regulation of CDK9/p53 and DNA damage pathway. This is the first study to demonstrate the beneficial effect of wogonin on PF, and its implication as a novel candidate for PF therapy.

Epithelium-derived exosomes promote silica nanoparticles-induced pulmonary fibroblast activation and collagen deposition via modulating fibrotic signaling pathways and their epigenetic regulations

BACKGROUND

In the context of increasing exposure to silica nanoparticles (SiNPs) and ensuing respiratory health risks, emerging evidence has suggested that SiNPs can cause a series of pathological lung injuries, including fibrotic lesions. However, the underlying mediators in the lung fibrogenesis caused by SiNPs have not yet been elucidated.

RESULTS

The in vivo investigation verified that long-term inhalation exposure to SiNPs induced fibroblast activation and collagen deposition in the rat lungs. In vitro, the uptake of exosomes derived from SiNPs-stimulated lung epithelial cells (BEAS-2B) by fibroblasts (MRC-5) enhanced its proliferation, adhesion, and activation. In particular, the mechanistic investigation revealed SiNPs stimulated an increase of epithelium-secreted exosomal miR-494-3p and thereby disrupted the TGF-β/BMPR2/Smad pathway in fibroblasts via targeting bone morphogenetic protein receptor 2 (BMPR2), ultimately resulting in fibroblast activation and collagen deposition. Conversely, the inhibitor of exosomes, GW4869, can abolish the induction of upregulated miR-494-3p and fibroblast activation in MRC-5 cells by the SiNPs-treated supernatants of BEAS-2B. Besides, inhibiting miR-494-3p or overexpression of BMPR2 could ameliorate fibroblast activation by interfering with the TGF-β/BMPR2/Smad pathway.

CONCLUSIONS

Our data suggested pulmonary epithelium-derived exosomes serve an essential role in fibroblast activation and collagen deposition in the lungs upon SiNPs stimuli, in particular, attributing to exosomal miR-494-3p targeting BMPR2 to modulate TGF-β/BMPR2/Smad pathway. Hence, strategies targeting exosomes could be a new avenue in developing therapeutics against lung injury elicited by SiNPs.

Pulmonary Fibrosis Ferret Model Demonstrates Sustained Fibrosis, Restrictive Physiology, and Aberrant Repair

Rationale

The role of MUC5B mucin expression in IPF pathogenesis is unknown. Bleomycin-exposed rodent models do not exhibit sustained fibrosis or airway remodeling. Unlike mice, ferrets have human-like distribution of MUC5B expressing cell types and natively express the risk-conferring variant that induces high MUC5B expression in humans. We hypothesized that ferrets would consequently exhibit aberrant repair to propagate fibrosis similar to human IPF.

Methods

Bleomycin (5U/kg) or saline-control was micro-sprayed intratracheally then wild-type ferrets were evaluated through 22 wks. Clinical phenotype was assessed with lung function. Fibrosis was assessed with µCT imaging and comparative histology with Ashcroft scoring. Airway remodeling was assessed with histology and quantitative immunofluorescence.

Results

Bleomycin ferrets exhibited sustained restrictive physiology including decreased inspiratory capacity, decreased compliance, and shifted Pressure-Volume loops through 22 wks. Volumetric µCT analysis revealed increased opacification of the lung bleomycin-ferrets. Histology showed extensive fibrotic injury that matured over time and MUC5B-positive cystic structures in the distal lung suggestive of honeycombing. Bleomycin ferrets had increased proportion of small airways that were double-positive for CCSP and alpha-tubulin compared to controls, indicating an aberrant 'proximalization' repair phenotype. Notably, this aberrant repair was associated with extent of fibrotic injury at the airway level.

Conclusions

Bleomycin-exposed ferrets exhibit sustained fibrosis through 22 wks and have pathologic features of IPF not found in rodents. Ferrets exhibited proximalization of the distal airways and other pathologic features characteristic of human IPF. MUC5B expression through native cell types may play a key role in promoting airway remodeling and lung injury in IPF.

Involvement of E3 ubiquitin ligase NEDD4-mediated YY1 ubiquitination in alleviating idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic and lethal lung disease characterized by progressive lung scarring. This study aims to elucidate the role of the E3 ubiquitin ligase NEDD4 in the ubiquitination of YY1 and its subsequent impact on TAB1 transcription, revealing a possible molecular mechanism in the development of IPF. Through bioinformatics analysis and both in vitro and in vivo experiments, we observed differential expression levels of NEDD4 and YY1 between normal and IPF samples, identifying NEDD4 as an upstream E3 ubiquitin ligase of YY1. Furthermore, binding sites for the transcription factor YY1 on the promoter region of TAB1 were discovered, indicating a direct interaction. In vitro experiments using HEPF cells showed that NEDD4 mediates the ubiquitination and degradation of YY1, leading to suppressed TAB1 transcription, thereby inhibiting cell proliferation and fibrogenesis. These findings were corroborated by in vivo experiments in an IPF mouse model, where the ubiquitination pathway facilitated by NEDD4 attenuated IPF progression through the downregulation of YY1 and TAB1 transcription. These results suggest that NEDD4 plays a crucial role in the development of IPF by modulating YY1 ubiquitination and TAB1 transcription, providing new insights into potential therapeutic targets for treating IPF.

Cadherin-11 targeted cell-specific liposomes enabled skin fibrosis treatment by inducing apoptosis

Continuous and aberrant activation of myofibroblasts is the hallmark of pathological fibrosis (e.g., abnormal wound healing). The deposition of excessive extracellular matrix (ECM) components alters or increases the stiffness of tissue and primarily accounts for multiple organ dysfunctions. Among various proteins, Cadherin-11 (CDH11) has been reported to be overexpressed on myofibroblasts in fibrotic tissues. Anti-apoptotic proteins such as (B cell lymphoma-2) (BCL-2) are also upregulated on myofibroblasts. Therefore, we hypothesize that CDH11 could be a targeted domain for cell-specific drug delivery and targeted inhibition of BCL-2 to ameliorate the development of fibrosis in the skin. To prove our hypothesis, we have developed liposomes (LPS) conjugated with CDH11 neutralizing antibody (antiCDH11) to target cell surface CDH11 and loaded these LPS with a BCL-2 inhibitor, Navitoclax (NAVI), to induce apoptosis of CDH11 expressing fibroblasts. The developed LPS were evaluated for physicochemical characterization, stability, in vitro therapeutic efficacy using dermal fibroblasts, and in vivo therapeutic efficacy in bleomycin-induced skin fibrosis model in mice. The findings from in vitro and in vivo studies confirmed that selectivity of LPS was improved towards CDH11 expressing myofibroblasts, thereby improving therapeutic efficacy with no indication of adverse effects. Hence, this novel research work represents a versatile LPS strategy that exhibits promising potential for treating skin fibrosis.

Combination of losartan with pirfenidone: a protective anti-fibrotic against pulmonary fibrosis induced by bleomycin in rats

Pirfenidone (PFD), one acceptable medication for treating idiopathic pulmonary fibrosis (IPF), is not well tolerated by patients at full doses. Hence, employing of some approaches such as combination therapy may be applicable for increasing therapeutic efficacy of PFD. Losartan (LOS), an angiotensin II receptor antagonist, could be a suitable candidate for combination therapy because of its stabilizing effect on the pulmonary function of IPF patients. Therefore, this study aimed to investigate the effects of LOS in combination with PFD on bleomycin (BLM)-induced lung fibrosis in rats. BLM-exposed rats were treated with LOS alone or in combination with PFD. The edema, pathological changes, level of transforming growth factor-β (TGF-β1), collagen content, and oxidative stress parameters were assessed in the lung tissues. Following BLM exposure, the inflammatory response, collagen levels, and antioxidant markers in rat lung tissues were significantly improved by PFD, and these effects were improved by combination with LOS. The findings of this in vivo study suggest that the combined administration of PFD and LOS may provide more potent protection against IPF than single therapy through boosting its anti-inflammatory, anti-fibrotic, and anti-oxidant effects. These results hold promise in developing a more effective therapeutic strategy for treating of lung fibrosis.

In vivo MRI and PET imaging in a translational ILD mouse model expressing non-resolving fibrosis and bronchiectasis-like pathology after repeated systemic exposure to bleomycin

Drug-induced interstitial lung disease (ILD) is crucial to detect early to achieve the best treatment outcome. Optimally, non-invasive imaging biomarkers can be used for early detection of disease progression and treatment follow-up. Therefore, reliable in vivo models are warranted in new imaging biomarker development to accelerate better-targeted treatment options. Single-dose bleomycin models have, for a long time, served as a reference model in fibrosis and lung injury research. Here, we aimed to use a clinically more relevant animal model by systemic exposure to bleomycin and assessing disease progression over time by combined magnetic resonance imaging (MRI) and positron emission tomography (PET) imaging.

Methods

C57BL/6 mice received bleomycin (i.p. 35iU/kg) or saline as control twice per week for 4 weeks. Mice were monitored until 2 weeks after cessation of bleomycin administration (w4 + 1 and w4 + 2), referred to as the resting period. MRI scans were performed in weeks 3 and 4 and during the resting weeks. [18F]FDG-PET was performed at the last week of dosing (w4) and 2 weeks after the last dosing (w4 + 2). Lung tissue sections were stained with Masson's trichrome and evaluated by modified Ashcroft scoring. Lung volume and lesion volumes were assessed using MRI, as well as 3D mapping of the central airways.

Results and discussion

Bleomycin-challenged mice showed increased lung weights (p < 0.05), while total lung volume was unchanged (w4 and onward). Histology analysis demonstrated fibrotic lesions emanating from the distal parts of the lung. Fibrosis progression was visualized by MRI with significantly increased high signal in bleomycin-exposed lungs compared to controls (p < 0.05). In addition, a significant increase in central airway diameter (p < 0.01) was displayed in bleomycin-exposed animals compared to controls and further continued to dilate as the disease progressed, comparing the bleomycin groups over time (p < 0.05-0.001). Lung [18F]FDG uptake was significantly elevated in bleomycin-exposed mice compared to controls (p < 0.05).

Conclusion

Non-invasive imaging displayed progressing lesions in the lungs of bleomycin-exposed mice, using two distinct MRI sequences and [18F]FDG-PET. With observed fibrosis progression emanating from distal lung areas, dilation of the central airways was evident. Taken together, this chronic bleomycin-exposure model is translationally more relevant for studying lung injury in ILD and particularly in the context of DIILD.

A novel tree shrew model of lipopolysaccharide-induced acute respiratory distress syndrome

INTRODUCTION

Acute respiratory distress syndrome (ARDS) is a leading cause of respiratory failure, with substantial attributable morbidity and mortality. The small animal models that are currently used for ARDS do not fully manifest all of the pathological hallmarks of human patients, which hampers both the studies of disease mechanism and drug development.

OBJECTIVES

To examine whether the phenotypic changes of primate-like tree shrews in response to a one-hit lipopolysaccharides (LPS) injury resemble human ARDS features.

METHODS

LPS was administered to tree shrews through intratracheal instillation; then, the animals underwent CT or PET/CT imaging to examine the changes in the structure and function of the whole lung. The lung histology was analyzed by H&E staining and immunohistochemical staining of inflammatory cells.

RESULTS

Results demonstrated that tree shrews exhibited an average survival time of 3-5 days after LPS insult, as well as an obvious symptom of dyspnea before death. The ratios of PaO2 to FiO2 (P/F ratio) were close to those of moderate ARDS in humans. CT imaging showed that the scope of the lung injury in tree shrews after LPS treatment were extensive. PET/CT imaging with 18F-FDG displayed an obvious inflammatory infiltration. Histological analysis detected the formation of a hyaline membrane, which is usually present in human ARDS.

CONCLUSION

This study established a lung injury model with a primate-like small animal model and confirmed that they have similar features to human ARDS, which might provide a valuable tool for translational research.

Regulation of miRNA-155-5p ameliorates NETosis in pulmonary fibrosis rat model via inhibiting its target cytokines IL-1β, TNF-α and TGF-β1

Idiopathic pulmonary fibrosis (IPF) is an age-related inflammatory disease with no cure up till now.It is accompanied by neutrophils infiltration as the main responders to inflammation and fibrosis. Importantly, neutrophils release neutrophil extracellular traps (NETs) through NETosis process. The function of microRNAs during inflammation became of great biological attention. Owing to microRNAs' central role in immune system, microRNA-155-5p (miR-155-5p) is intensely involved in the inflammatory response. Capsaicin (Cap) is a bioactive compound that exhibits antioxidative and anti-inflammatory functions. Recent studies have shown its role in regulation of certain microRNAs' expressions. Accordingly, the present study aims to investigate the effect of miR-155-5p regulation in suppressing NETs production via ameliorating its target inflammatory cytokines, IL-1ß, TNF-α and TGF-ß1, in bleomycin (BLM)-induced pulmonary fibrosis rat model treated by Cap. The obtained results demonstrated that miR-155-5p downregulation was associated with significant decrease in IL-1ß, TNF-α, TGF-β1, which consequently, reduced hydroxyproline (HYP), NETs activity markers as NE and PAD-4, and alleviated CTGF levels in lung tissues of animals treated by Cap. Furthermore, NETosis ultrastructure examination by transmission electron microscope (TEM), MPO immunohistochemical staining and histopathological studies confirmed an abolishment in NETs formation and an improvement in lung tissue architecture in Cap-treated rats. This study concluded that Cap quenched the inflammatory response through interrupting IL-1β, TNF-α and TGF-β1 pathway via modulating miR-155-5p expression. In addition, Cap was able to alleviate pulmonary NETosis markers by restraining NETs activity markers. These findings provide novel insight into the application of Cap-based treatment in ameliorating pulmonary damage in IPF.

Endothelial anthrax toxin receptor 2 plays a protective role in liver fibrosis

Hepatocellular carcinoma is one of the leading cancers worldwide and is a potential consequence of fibrosis. Therefore, the identification of key cellular and molecular mechanisms involved in liver fibrosis is an important goal for the development of new strategies to control liver-related diseases. Here, single-cell RNA sequencing data (GSE136103 and GES181483) of clinical liver non-parenchymal cells were analyzed to identify cellular and molecular mechanisms of liver fibrosis. The proportion of endothelial subpopulations in cirrhotic livers was significantly higher than that in healthy livers. Gene ontology and gene set enrichment analysis of differentially expressed genes in the endothelial subgroups revealed that extracellular matrix (ECM)-related pathways were significantly enriched. Since anthrax toxin receptor 2 (ANTXR2) interacts with the ECM, the expression of ANTXR2 in the liver endothelium was analyzed. ANTXR2 expression in the liver endothelium of wild-type (WT) mice significantly decreased after a 4-time sequential injection of carbon tetrachloride (CCl4) to induce liver fibrosis. Next, conditional knockout mice selectively lacking Antxr2 in endothelial cells were generated. After endothelial-specific Antxr2 knockout mice were subjected to the CCl4 model, the degree of liver fibrosis in the knockout group was significantly more severe than that in the control group. In addition, ANTXR2 in human umbilical vein endothelial cells promoted matrix metalloproteinase 2 (MMP2) activation to degrade the ECM in vitro. Finally, endothelial-specific overexpression of Antxr2 alleviated the development of liver fibrosis following adeno-associated virus treatment. Collectively, these results suggested that endothelial ANTXR2 plays a protective role in liver fibrosis. This function of ANTXR2 may be achieved by promoting MMP2 activation to degrade the ECM.

Tuberostemonine may enhance the function of the SLC7A11/glutamate antiporter to restrain the ferroptosis to alleviate pulmonary fibrosis

ETHNOPHARMACOLOGICAL RELEVANCE

Stemona is a medicinal plant that has been used in China for thousands of years to treat respiratory diseases such as cough and tuberculosis. The tuberostemonine is the component of the Stemona tuberosa Lour., Stemona sessilifolia (Miq.) Miq. or Stemona japonica (Blume) Miq. (The plant name has been checked with http://www.theplantlist.org), of which multiple biological activities has been verified. However, whether it may alleviate pulmonary fibrosis via regulating ferroptosis mechanism has not been confirmed.

AIM OF THE STUDY

The aim of this study is to observe whether tuberostemonine alleviates pulmonary fibrosis by enhancing the function of the SLC7A11/glutamate antiporter to restrain the ferroptosis.

MATERIALS AND METHODS

We validated the effects of tuberostemonine and ferroptosis on TGF-β1-induced proliferation of human lung fibroblast and bleomycin-induced pulmonary fibrosis in mice. In vitro, the ferroptosis effect of TGF-β1 on human lung fibroblast were examined and the activity of ɑ-SMA, collagen, hydroxyproline and ferrous ions in cells were also examined. In vivo, ferroptosis impacts respiratory function. Inflammatory manifestations, hydroxyproline, collagen activity and ferrous ions in the lung or blood were subject to evaluation.

RESULTS

Tuberostemonine significantly improved respiratory function in mice with bleomycin-induced pulmonary fibrosis, decreased cellular and lung hydroxyproline content, reduced inflammation and collagen deposition in cells and lung, and promoted an increase in the SLC7A11 and GPX4 proteins. Tuberostemonine inhibits the ferroptosis phenomenon, up-regulates SLC7A11, GPX4 and GSH, and down-regulates the accumulation of iron and ROS.

CONCLUSIONS

Tuberostemonine significantly inhibited ferroptosis and improved pulmonary fibrosis both in vivo and vitro.

Pulmonary administration of tetrandrine loaded Zinc-Alginate nanogels attenuates pulmonary fibrosis in rats

Pulmonary fibrosis is a chronic and progressive disease, current systemic administration is not fully effective with many side effects, such as gastrointestinal and liver injury. The pulmonary delivery system for pulmonary fibrosis may contribute to maximize therapeutic benefit. Natural compounds might have prominence as potential drug candidates, but the low bioavailabilities affect their clinical use. Tetrandrine is a natural alkaloid with good anti-inflammatory, antifibrogenetic and antioxidant effects, and it is used as a clinical therapeutic drug for the treatment of silicosis in China. In the present study, we explore a new strategy of pulmonary delivery system to improve low solubility and pesticide effect of tetrandrine. Tetrandrine was loaded into alginate nanogels by reverse microemulsion method. The release behavior of tetrandrine reached zero-order kinetics release and the maximum free radical clearance rates reached up to 90%. The pulmonary fibrosis rats were treated with tetrandrine nanogels by using ultrasonic atomizing inhalation. Tetrandrine nanogels decreased the development and progression of fibrosis by reducing inflammation response and bating the deposition of extra cellular matrix. In conclusion, ultrasonic atomizing inhalation of tetrandrine nanogels provided a new therapeutic strategy for pulmonary fibrosis.

Unveiling Vaginal Fibrosis: A Novel Murine Model Using Bleomycin and Epithelial Disruption

Objective

Develop, validate, and characterize a fibrotic murine vaginal wound healing model using bleomycin instillations and epithelial disruption.

Approach

We tested the effect of repeated bleomycin instillations with mucosal layer disruption on induction of vaginal fibrosis. Tissue samples collected at various time points were analyzed for fibrosis-related gene expression changes and collagen content.

Results

Low (1.5U/kg) and high-dose (2.5U/kg) bleomycin instillations alone did not induce fibrosis, but when high-dose bleomycin was combined with epithelial disruption, increased pro-fibrotic gene expression and trichrome staining were observed. To evaluate spatial and temporal changes in the ECM structure and gene expression, tissue samples were collected at 1 day, 3 weeks, and 6 weeks after bleomycin and epithelial disruption. Data analyses revealed a significant decrease in matrix metabolizing genes and an increase in pro-fibrotic genes and inhibitors of matrix metabolizing genes in the bleomycin plus epithelial disruption group at 3 weeks. Elevated levels of the profibrotic genes Acta2 , Col1a1 , and Col3a were exclusively detected in this group at 3 weeks, and trichrome staining confirmed increased collagen content after 3 weeks. Hydroxyproline levels showed a tendency towards elevation at 3 weeks (p=0.12) and 6 weeks (p=0.14), indicating fibrosis manifestation at 3 weeks and resolution by 6 weeks post-instillation and epithelial disruption.

Innovation

We combined bleomycin instillations with epithelial disruption to induce fibrosis and understand the mechanisms of the vaginal repair process.

Conclusions

Epithelial disruption combined with bleomycin induces murine vaginal fibrosis within three weeks, characterized by increased collagen synthesis. Remarkably, the vaginal tissue fully recovers within six weeks, elucidating the regenerative capacity of the vagina.

Cellular and molecular mechanisms of fibrosis and resolution in bleomycin-induced pulmonary fibrosis mouse model revealed by spatial transcriptome analysis

The bleomycin-induced pulmonary fibrosis mouse model is commonly used in idiopathic pulmonary fibrosis research, but its cellular and molecular changes and efficiency as a model at the molecular level are not fully understood. In this study, we used spatial transcriptome technology to investigate the cellular and molecular changes in the lungs of bleomycin-induced pulmonary fibrosis mouse models. Our analyses revealed cell dynamics during fibrosis in epithelial cells, mesenchymal cells, immunocytes, and erythrocytes with their spatial distribution available. We confirmed the differentiation of the alveolar type II (AT2) cell type expressing Krt8, and we inferred their trajectories from both the AT2 cells and club cells. In addition to the fibrosis process, we also noticed evidence of self-resolving, especially to identify possible self-resolving related genes, including Prkca. Our findings provide insights into the cellular and molecular mechanisms underlying fibrosis resolution and represent the first spatiotemporal transcriptome dataset of the bleomycin-induced fibrosis mouse model.

Inhalation Lenalidomide-Loaded Liposome for Bleomycin-Induced Pulmonary Fibrosis Improvement

Idiopathic pulmonary fibrosis (IPF) is a progressive, fibrotic interstitial lung disease with unclear etiology and increasing prevalence. Pulmonary administration can make the drug directly reach the lung lesion location and reduce systemic toxic and side effects. The effectiveness of lenalidomide (Len) liposomal lung delivery in idiopathic pulmonary fibrosis was investigated. Len liposomes (Len-Lip) were prepared from soybean lecithin, cholesterol (Chol), and medicine in different weight ratios by thin film hydration method. The Len-Lip were spherical in shape with an average size of 226.7 ± 1.389 nm. The liposomes with a higher negative zeta potential of around - 34 mV, which was conducive to improving stability by repelling each other. The drug loading and encapsulation rate were 2.42 ± 0.07% and 85.47 ± 2.42%. Len-Lip had little toxicity at the cellular level and were well taken up by cells. At bleomycin-induced pulmonary fibrosis model mice, inhalation Len-Lip could improve lung function and decrease lung hydroxyproline contents, and alleviate pulmonary fibrosis state. Inhalation Len-Lip provided a reference for the treatment of idiopathic pulmonary fibrosis.

Therapeutic effects of fatty acid binding protein 1 in mice with pulmonary fibrosis by regulating alveolar epithelial regeneration

INTRODUCTION

Idiopathic pulmonary fibrosis is a progressive fibrotic lung disease with limited therapeutic options and high lethality, related to alveolar type II epithelial (ATII) cell dysregulation, the abnormal repair of alveolar epithelial cells and activation of fibroblasts promote the development of pulmonary fibrosis. Fatty acid binding protein 1 (FABP1) was significantly downregulated in the fibrotic state by proteomics screening in our previous date, and the ATII cell dysregulation can be mediated by FABP1 via regulating fatty acid metabolism and intracellular transport. The aim of this study was to evaluate the role and potential mechanism of FABP1 in the development of pulmonary fibrosis.

METHODS

Proteomics screening was used to detect changes of the protein profiles in two different types (induced by bleomycin and silica, respectively) of pulmonary fibrosis models. The localisation of FABP1 in mouse lung was detected by Immunofluorescence and immunohistochemistry. Experimental methods such as lung pathology, micro-CT, western blotting, small animal imaging in vivo, EdU, etc were used to verify the role of FABP1 in pulmonary fibrosis.

RESULTS

The expression of FABP1 in the mouse lung was significantly reduced in the model of pulmonary fibrosis from our proteomic analysis and immunological methods, the double immunofluorescence staining showed that FABP1 was mainly localised in type II alveolar epithelial cells. Additionally, the expression of FABP1 was negatively correlated with the progression of pulmonary fibrosis. Further in vivo and in vitro experiments showed that overexpression of FABP1 alleviated pulmonary fibrosis by protecting alveolar epithelium from injury and promoting cell survival.

CONCLUSION

Our findings provide a proof-of-principle that FABP1 may represent an effective treatment for pulmonary fibrosis by regulating alveolar epithelial regeneration, which may be associated with the fatty acid metabolism in ATII cells.

AS1411 aptamer tagged PEGylated liposomes as a smart nanocarrier for tumor-specific delivery of Withaferin A for mitigating pulmonary metastasis

Metastasis is the most challenging health problem contributing to about 90 % of cancer-related deaths worldwide. Metastatic tumors are highly aggressive and resistant to the most available therapeutic options. Hence, innovative therapeutic approaches are required to target metastatic tumors selectively. In this study, we prepared AS1411 functionalized Withaferin A loaded PEGylated nanoliposomes (ALW) and investigated its therapeutic effect in B16F10 induced in pulmonary metastasis mice models. The prepared formulations' size and morphological properties were evaluated using dynamic light scattering system and Transmission electron microscope. ALW had spherical-shaped nanosized particles with a size of 118 nm and an encapsulation efficacy of 82.5 %. TEM analysis data indicated that ALW has excellent dispersibility and uniform spherical nano-size particles. ALW inhibited cell viability, and induced cell apoptosis of B16F10. In vivo, the pulmonary metastasis study in C57BL/6 mice revealed that the ALW significantly (p < 0.01) improved the encapsulated WA anti-metastatic activity and survival rate compared to WA or LW treated groups. ALW significantly (p < 0.01) downregulated the levels of IL-6, TNF-α, and IL-1β and significantly reduced the lung collagen hydroxyproline, hexosamine, and uronic acid content in metastatic tumor bearing animals compared to WA or LW. Gene expression levels of MMPs and NF-κB were downregulated in ALW treated metastatic pulmonary tumor-bearing mice. These findings demonstrate that the AS1411 functionalized Withaferin A loaded PEGylated nanoliposomes could be a promising nanoliposomal formulation for targeting metastatic tumors.

The Value of Micro-CT in the Diagnosis of Lung Carcinoma: A Radio-Histopathological Perspective

Micro-computed tomography (micro-CT) is a relatively new imaging modality and the three-dimensional (3D) images obtained via micro-CT allow researchers to collect both quantitative and qualitative information on various types of samples. Micro-CT could potentially be used to examine human diseases and several studies have been published on this topic in the last decade. In this study, the potential uses of micro-CT in understanding and evaluating lung carcinoma and the relevant studies conducted on lung and other tumors are summarized. Currently, the resolution of benchtop laboratory micro-CT units has not reached the levels that can be obtained with light microscopy, and it is not possible to detect the histopathological features (e.g., tumor type, adenocarcinoma pattern, spread through air spaces) required for lung cancer management. However, its ability to provide 3D images in any plane of section, without disturbing the integrity of the specimen, suggests that it can be used as an auxiliary technique, especially in surgical margin examination, the evaluation of tumor invasion in the entire specimen, and calculation of primary and metastatic tumor volume. Along with future developments in micro-CT technology, it can be expected that the image resolution will gradually improve, the examination time will decrease, and the relevant software will be more user friendly. As a result of these developments, micro-CT may enter pathology laboratories as an auxiliary method in the pathological evaluation of lung tumors. However, the safety, performance, and cost effectiveness of micro-CT in the areas of possible clinical application should be investigated. If micro-CT passes all these tests, it may lead to the convergence of radiology and pathology applications performed independently in separate units today, and the birth of a new type of diagnostician who has equal knowledge of the histological and radiological features of tumors.

An evaluation of the effects of glabridin and dexamethasone in bleomycin-induced pulmonary fibrosis: The role of BKCa channels

Pulmonary fibrosis is a refractory entity with a progressive course and no effective therapeutic options. The purpose of this study was to investigate the potential involvement of both glabridin and dexamethasone (Dex) in inflammatory and fibrotic responses in a bleomycin (BLM)-induced pulmonary fibrosis model. The role of Ca+2-activated K+ channels (BKCa) in the anti-inflammatory effects of glabridin was also examined. Adult female Wistar rats were divided into six groups: saline control, BLM, BLM+Gla (BLM+glabridin), BLM+IbTX+Gla (BLM+iberiotoxin+Gla, BKCa channel blocker), BLM+Dex, and BLM+Veh (BLM+dimethylsulfoxide). Inflammatory cell count values, and interleukin (IL)- 6, tumor necrosis factor (TNF)-α, glutathione (GSH), and malondialdehyde (MDA) levels were measured in bronchoalveolar lavage (BAL) fluid in order to measure fibrosis and the extent of tissue damage, in addition to stereological, immunohistochemical and histopathological examinations. Whole-body plethysmography was used to evaluate pulmonary function. Treatments with glabridin and Dex significantly reduced pathological injury and fibrosis in lung tissue, levels of TNF-α and IL-6 increased by BLM, oxidative stress, and fibrillin-1 scoring. Glabridin and Dex also reversed the increases observed in neutrophil, lymphocyte, and macrophage counts in BAL fluid induced by BLM. Glabridin and Dex were found to ameliorate the abnormal course of PIF, PEF, EV, TV, f, and Penh values caused by BLM. Our findings suggest that glabridin and Dex may exert anti-fibrotic effects by suppressing oxidative stress and inhibiting the inflammatory response, and that glabridin may improve pulmonary function through activation of BKCa channels. Both glabridin and Dex may therefore be of therapeutic use in pulmonary fibrosis.

Longitudinal assessment of bleomycin-induced pulmonary fibrosis by evaluating TGF-β1/Smad2, Nrf2 signaling and metabolomic analysis in mice

INTRODUCTION

Pulmonary fibrosis (PF) is characterized by an increase in collagen synthesis and deposition of extracellular matrix. Several factors, including transforming growth factor-β1 (TGF-β1), mothers against decapentaplegic homolog family proteins (Smad), and alpha-smooth muscle actin (α-SMA) trigger extracellular matrix (ECM) accumulation, fibroblast to myofibroblasts conversion, and epithelial-to-mesenchymal-transition (EMT) leading to PF. However, the role of cellular defense mechanisms such as the role of nuclear factor erythroid 2-related factor 2 (Nrf2) signaling during the onset and progression of PF is not understood completely.

AIM

The present study aims to analyze the involvement of TGF-β1/Smad signaling, and Nrf2 in the EMT and metabolic alterations that promote fibrosis in a time-dependent manner using bleomycin (BLM)-induced PF model in C57BL/6 mice.

KEY FINDINGS

Histopathological studies revealed loss of lung architecture and increased collagen deposition in BLM-exposed mice. BLM upregulated TGF-β1/Smad signaling and α-SMA at all time-points. The gradual increase in the accumulation of α-SMA and collagen implied the progression of PF. BLM exposure raises Nrf2 throughout each specified time-point, which suggests that Nrf2 activation might be responsible for TGF-β1-induced EMT and the development of PF. Further, metabolomic studies linked the development of PF to alterations in metabolic pathways. The pentose phosphate pathway (PPP) was consistently enriched across all the time-points. Additionally, alterations in 22 commonly enriched pathways, associated with fatty acid (FA) and amino acid metabolism were observed in 30- and 60-days.

SIGNIFICANCE

This study elucidates the association of TGF-β1/Smad and Nrf2 signaling in the EMT and metabolic alterations associated with the etiology and progression of PF.

Untargeted Metabolomics Reveals Alterations of Rhythmic Pulmonary Metabolism in IPF

Idiopathic pulmonary fibrosis (IPF) is a chronic and progressive condition characterized by the impairment of alveolar epithelial cells. Despite continued research efforts, the effective therapeutic medication is still absent due to an incomplete understanding of the underlying etiology. It has been shown that rhythmic alterations are of significant importance in the pathophysiology of IPF. However, a comprehensive understanding of how metabolite level changes with circadian rhythms in individuals with IPF is lacking. Here, we constructed an extensive metabolite database by utilizing an unbiased reference system culturing with 13C or 15N labeled nutrients. Using LC-MS analysis via ESI and APCI ion sources, 1300 potential water-soluble metabolites were characterized and applied to evaluate the metabolic changes with rhythm in the lung from both wild-type mice and mice with IPF. The metabolites, such as glycerophospholipids and amino acids, in WT mice exhibited notable rhythmic oscillations. The concentrations of phospholipids reached the highest during the fast state, while those of amino acids reached their peak during fed state. Similar diurnal variations in the metabolite rhythm of amino acids and phospholipids were also observed in IPF mice. Although the rhythmic oscillation of metabolites in the urea cycle remained unchanged, there was a significant up-regulation in their levels in the lungs of IPF mice. 15N-ammonia in vivo isotope tracing further showed an increase in urea cycle activity in the lungs of mice with IPF, which may compensate for the reduced efficiency of the hepatic urea cycle. In sum, our metabolomics database and method provide evidence of the periodic changes in lung metabolites, thereby offering valuable insights to advance our understanding of metabolic reprogramming in the context of IPF.

Investigating the role of platelets and platelet-derived transforming growth factor-β in idiopathic pulmonary fibrosis

Transforming growth factor-β1 (TGFβ1) is the key profibrotic cytokine in idiopathic pulmonary fibrosis (IPF), but the primary source of this cytokine in this disease is unknown. Platelets have abundant stores of TGFβ1, although the role of these cells in IPF is ill-defined. In this study, we investigated whether platelets, and specifically platelet-derived TGFβ1, mediate IPF disease progression. Patients with IPF and non-IPF patients were recruited to determine platelet reactivity, and separate cohorts of patients with IPF were followed for mortality. To study whether platelet-derived TGFβ1 modulates pulmonary fibrosis (PF), mice with a targeted deletion of TGFβ1 in megakaryocytes and platelets (TGFβ1fl/fl.PF4-Cre) were used in the well-characterized bleomycin-induced pulmonary fibrosis (PF) animal model. In a discovery cohort, we found significantly higher mortality in patients with IPF who had elevated platelet counts within the normal range. However, our validation cohort did not confirm this observation, despite significantly increased platelets, neutrophils, active TGFβ1, and CCL5, a chemokine produced by inflammatory cells, in the blood, lung, and bronchoalveolar lavage (BAL) of patients with IPF. In vivo, we showed that despite platelets being readily detected within the lungs of bleomycin-treated mice, neither the degree of pulmonary inflammation nor fibrosis was significantly different between TGFβ1fl/fl.PF4-Cre and control mice. Our results demonstrate for the first time that platelet-derived TGFβ1 does not significantly mediate inflammation or fibrosis in a PF animal model. Furthermore, our human studies revealed blood platelet counts do not consistently predict mortality in IPF but other platelet-derived mediators, such as C-C chemokine ligand 5 (CCL5), may promote neutrophil recruitment and human IPF.NEW & NOTEWORTHY Platelets are a rich source of profibrotic TGFβ; however, the role of platelets in idiopathic pulmonary fibrosis (IPF) is unclear. We identified that patients with IPF have significantly more platelets, neutrophils, and active TGFβ in their airways than control patients. Using an animal model of IPF, we demonstrated that platelet-derived TGFβ does not significantly drive lung fibrosis or inflammation. Our findings offer a better understanding of platelets in both human and animal studies of IPF.

Omentin-1 induces mechanically activated fibroblasts lipogenic differentiation through pkm2/yap/pparγ pathway to promote lung fibrosis resolution

Idiopathic pulmonary fibrosis (IPF) is a progressive and fatal lung disease characterized by extensive extracellular matrix (ECM) deposition by activated myofibroblasts, which are specialized hyper-contractile cells that promote ECM remodeling and matrix stiffening. New insights on therapeutic strategies aimed at reversing fibrosis by targeting myofibroblast fate are showing promise in promoting fibrosis resolution. Previously, we showed that a novel adipocytokine, omentin-1, attenuated bleomycin (BLM)-induced lung fibrosis by reducing the number of myofibroblasts. Apoptosis, deactivation, and reprogramming of myofibroblasts are important processes in the resolution of fibrosis. Here we report that omentin-1 reverses established lung fibrosis by promoting mechanically activated myofibroblasts dedifferentiation into lipofibroblasts. Omentin-1 promotes myofibroblasts lipogenic differentiation by inhibiting dimerization and nuclear translocation of glycolytic enzymes pyruvate kinase isoform M2 (PKM2) and activation of the downstream Yes-associated protein (YAP) by increasing the cofactor fructose-1,6-bisphosphate (F1, 6BP, FBP). Moreover, omentin-1 activates proliferator-activated receptor gamma (PPARγ) signaling, the master regulator of lipogenesis, and promotes the upregulation of the lipogenic differentiation-related protein perilipin 2 (PLIN2) by suppressing the PKM2-YAP pathway. Ultimately, omentin-1 facilitates myofibroblasts transformation into the lipofibroblast phenotype, with reduced collagen synthesis and enhanced degradation properties, which are crucial mechanisms to clear the ECM deposition in fibrotic tissue, leading to fibrosis resolution. Our results indicate that omentin-1 targets mechanical signal accelerates fibrosis resolution and reverses established lung fibrosis by promoting myofibroblasts lipogenic differentiation, which is closely associated with ECM clearance in fibrotic tissue. These findings suggest that targeting mechanical force to promote myofibroblast lipogenic differentiation is a promising therapeutic strategy against persistent lung fibrosis.

Relaxin-Loaded Inhaled Porous Microspheres Inhibit Idiopathic Pulmonary Fibrosis and Improve Pulmonary Function Post-Bleomycin Challenges

Idiopathic pulmonary fibrosis (IPF) causes worsening pulmonary function, and no effective treatment for the disease etiology is available now. Recombinant Human Relaxin-2 (RLX), a peptide agent with anti-remodeling and anti-fibrotic effects, is a promising biotherapeutic candidate for musculoskeletal fibrosis. However, due to its short circulating half-life, optimal efficacy requires continuous infusion or repeated injections. Here, we developed the porous microspheres loading RLX (RLX@PMs) and evaluated their therapeutic potential on IPF by aerosol inhalation. RLX@PMs have a large geometric diameter as RLX reservoirs for a long-term drug release, but smaller aerodynamic diameter due to their porous structures, which were beneficial for higher deposition in the deeper lungs. The results showed a prolonged release over 24 days, and the released drug maintained its peptide structure and activity. RLX@PMs protected mice from excessive collagen deposition, architectural distortion, and decreased compliance after a single inhalation administration in the bleomycin-induced pulmonary fibrosis model. Moreover, RLX@PMs showed better safety than frequent gavage administration of pirfenidone. We also found RLX-ameliorated human myofibroblast-induced collagen gel contraction and suppressed macrophage polarization to the M2 type, which may be the reason for reversing fibrosis. Hence, RLX@PMs represent a novel strategy for the treatment of IPF and suggest clinical translational potential.

Empagliflozin Ameliorates Bleomycin-Induced Pulmonary Fibrosis in Rats by Modulating Sesn2/AMPK/Nrf2 Signaling and Targeting Ferroptosis and Autophagy

Pulmonary fibrosis (PF) is a life-threatening disorder that severely disrupts normal lung architecture and function, resulting in severe respiratory failure and death. It has no definite treatment. Empagliflozin (EMPA), a sodium-glucose cotransporter 2 (SGLT2) inhibitor, has protective potential in PF. However, the mechanisms underlying these effects require further elucidation. Therefore, this study aimed to evaluate the ameliorative effect of EMPA against bleomycin (BLM)-induced PF and the potential mechanisms. Twenty-four male Wister rats were randomly divided into four groups: control, BLM treated, EMPA treated, and EMPA+BLM treated. EMPA significantly improved the histopathological injuries illustrated by both hematoxylin and eosin and Masson's trichrome-stained lung tissue sections, as confirmed by electron microscopic examination. It significantly reduced the lung index, hydroxyproline content, and transforming growth factor β1 levels in the BLM rat model. It had an anti-inflammatory effect, as evidenced by a decrease in the inflammatory cytokines' tumor necrosis factor alpha and high mobility group box 1, inflammatory cell infiltration into the bronchoalveolar lavage fluid, and the CD68 immunoreaction. Furthermore, EMPA mitigated oxidative stress, DNA fragmentation, ferroptosis, and endoplasmic reticulum stress, as evidenced by the up-regulation of nuclear factor erythroid 2-related factor expression, heme oxygenase-1 activity, glutathione peroxidase 4 levels, and a decrease in C/EBP homologous protein levels. This protective potential could be explained on the basis of autophagy induction via up-regulating lung sestrin2 expression and the LC3 II immunoreaction observed in this study. Our findings indicated that EMPA protected against BLM-induced PF-associated cellular stress by enhancing autophagy and modulating sestrin2/adenosine monophosphate-activated protein kinase/nuclear factor erythroid 2-related factor 2/heme oxygenase 1 signaling.

The Chemistry and Biology of Collagen Hybridization

Collagen provides mechanical and biological support for virtually all human tissues in the extracellular matrix (ECM). Its defining molecular structure, the triple-helix, could be damaged and denatured in disease and injuries. To probe collagen damage, the concept of collagen hybridization has been proposed, revised, and validated through a series of investigations reported as early as 1973: a collagen-mimicking peptide strand may form a hybrid triple-helix with the denatured chains of natural collagen but not the intact triple-helical collagen proteins, enabling assessment of proteolytic degradation or mechanical disruption to collagen within a tissue-of-interest. Here we describe the concept and development of collagen hybridization, summarize the decades of chemical investigations on rules underlying the collagen triple-helix folding, and discuss the growing biomedical evidence on collagen denaturation as a previously overlooked ECM signature for an array of conditions involving pathological tissue remodeling and mechanical injuries. Finally, we propose a series of emerging questions regarding the chemical and biological nature of collagen denaturation and highlight the diagnostic and therapeutic opportunities from its targeting.

The longitudinal and regional analysis of bleomycin-induced pulmonary fibrosis in mice by microcomputed tomography

Introduction

Microcomputed tomography (micro-CT) is powerful for assessment of the progression of lung fibrosis in animal model, but current whole lung analysis (WLA) methods are time-consuming. Here, a longitudinal and regional analysis (LRA) method was developed to assess fibrosis easily and quickly by micro-CT.

Method

Firstly, we investigated the distribution pattern of lesions in BLM-induced pulmonary fibrosis mice. Then, the VOIs for LRA were selected based on the anatomical locations and we compared the robustness, accuracy, repeatability, analysis time of LRA to WLA. Additionally, LRA was applied to assess different stages of pulmonary fibrosis, and was validated with conventional endpoint measurements (such as lung hydroxyproline and histopathology).

Results

The lesions of fibrosis in 66 bleomycin (BLM)-induced pulmonary fibrosis mice were mostly in the middle and upper parts of lungs. By applying LRA, the percentages of high-density voxels in selected volumes of interest (VOIs) were well correlated with that in WLA both at Day 7 and Day 21 after bleomycin induction (R² = 0.8784 and 0.8464, respectively). The relative standard deviation (RSD) of the percentage of high-density voxels in the VOIs was lower than that of WLA (P < 0.05). The cost time of LRA was shorter than that of WLA (P < 0.05) and the accuracy of LRA was further confirmed by the histological analysis and biochemical quantification of hydroxyproline.

Conclusion

LRA is probably an easier and more time-saving method to assess fibrosis formation and evaluate treatment efficacy.