Prevention of bleomycin-induced pulmonary fibrosis by vaccination with the Tocilizumab mimotope.

Mimotope, a kind of peptide vaccine, is developed to bind natural receptor and inhibit the downstream signaling. We have demonstrated that the vaccination of Tocilizumab mimotopes could alleviate the renal fibrosis by interfering with both IL-6 and ferroptosis signaling. However, the effect of the vaccination of Tocilizumab mimotopes on the fibroblast was not investigated in previous study. Thus, we sought to explore the changes in the fibroblast induced by the Tocilizumab mimotopes vaccination. Bleomycin instillation was performed to construct the pulmonary fibrosis model after the immunization of Tocilizumab mimotopes. Lung histological analysis showed that the Tocilizumab mimotopes could significantly reduce the maladaptive repairment and abnormal remodeling. Immunoblotting assay and fluorescence staining showed that Immunization with the Tocilizumab mimotopes reduces the accumulation of fibrosis-related proteins. High level of lipid peroxidation product was observed in the animal model, while the Tocilizumab mimotopes vaccination could reduce the generation of lipid peroxidation product. Mechanism analysis further showed that Nrf-2 signaling, but not GPX-4 and FSP-1 signaling, was upregulated, and reduced the lipid peroxidation. Our results revealed that in the BLM-induced pulmonary fibrosis, high level of lipid peroxidation product was significantly accumulation in the lung tissues, which might lead to the occurrence of ferroptosis. The IL-6 pathway block therapy could inhibit lipid peroxidation product generation in the lung tissues by upregulating the Nrf-2 signaling, and further alleviate the pulmonary fibrosis.

Ivermectin ameliorates bleomycin-induced lung fibrosis in male rats by inhibiting the inflammation and oxidative stress.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is a pulmonary fibrotic disease characterized by a poor prognosis, which its pathogenesis involves the accumulation of abnormal fibrous tissue, inflammation, and oxidative stress. Ivermectin, a positive allosteric modulator of GABAA receptor, exerts anti-inflammatory and antioxidant properties in preclinical studies. The present study investigates the potential protective effects of ivermectin treatment in rats against bleomycin-induced IPF. MATERIALS AND METHODS: The present study involved 42 male Wistar rats, which were divided into five groups: control (without induction of IPF), bleomycin (IPF-induced by bleomycin 2.5 mg/kg, by intratracheal administration), and three fibrosis groups receiving ivermectin (0.5, 1, and 3 mg/kg). lung tissues were harvested for measurement of oxidative stress [via myeloperoxidase (MPO), superoxide dismutase (SOD), glutathione (GSH)] and inflammatory markers (tumor necrosis factor-α [TNF-α], interleukin-1ß [IL-1ß], and transforming growth factor-ß [TGF-ß]). Histological assessments of tissue damage were performed using hematoxylin-eosin (H&E) and Masson's trichrome staining methods. RESULTS: The induction of fibrosis via bleomycin was found to increase levels of MPO as well as TNF-α, IL-1ß, and TGF-ß while decrease SOD activity and GSH level. Treatment with ivermectin at a dosage of 3 mg/kg was able to reverse the effects of bleomycin-induced fibrosis on these markers. In addition, results from H&E and Masson's trichrome staining showed that ivermectin treatment at this same dose reduced tissue damage and pulmonary fibrosis. CONCLUSION: The data obtained from this study indicate that ivermectin may have therapeutic benefits for IPF, likely due to its ability to reduce inflammation and mitigate oxidative stress-induced toxicity.

Hydroxytyrosol Alleviates Methotrexate-Induced Pulmonary Fibrosis in Rats: Involvement of TGF-ß1, Tissue Factor, and VEGF.

Methotrexate (MTX) is an indispensable drug used for the treatment of many autoimmune and cancerous diseases. However, its clinical use is associated with serious side effects, such as lung fibrosis. The main objective of this study is to test the hypothesis that hydroxytyrosol (HT) can mitigate MTX-induced lung fibrosis in rats while synergizing MTX anticancer effects. Pulmonary fibrosis was induced in the rats using MTX (14 mg/kg/week, per os (p.o.)). The rats were treated with or without HT (10, 20, and 40 mg/kg/d p.o.) or dexamethasone (DEX; 0.5 mg/kg/d, intraperitoneally (i.p.)) for two weeks concomitantly with MTX. Transforming growth factor beta 1 (TGF-ß1), interleukin-4 (IL-4), thromboxane A2 (TXA2), vascular endothelial growth factor (VEGF), 8-hydroxy-2-deoxy-guanosine (8-OHdG), tissue factor (TF) and fibrin were assessed using enzyme-linked immunosorbent assay (ELISA), immunofluorescence, and RT-PCR. Pulmonary fibrosis was manifested by an excessive extracellular matrix (ECM) deposition and a marked increase in TGF-ß1 and IL-4 in lung tissues. Furthermore, cotreatment with HT or dexamethasone (DEX) significantly attenuated MTX-induced ECM deposition, TGF-ß1, and IL-4 expression. Similarly, HT or DEX notably reduced hydroxyproline contents, TXA2, fibrin, and TF expression in lung tissues. Moreover, using HT or DEX downregulated the gene expression of TF. A significant decrease in lung contents of VEGF, IL-8, and 8-OHdG was also observed in HT + MTX- or DEX + MTX -treated animals in a dose-dependent manner. Collectively, the results of our study suggest that HT might represent a potential protective agent against MTX-induced pulmonary fibrosis.

Trigonelline mitigates bleomycin-induced pulmonary inflammation and fibrosis: Insight into NLRP3 inflammasome and SPHK1/S1P/Hippo signaling modulation.

AIMS: Pulmonary fibrosis (PF) is a chronic interstitial lung disease with an increasing incidence following the COVID-19 outbreak. Pirfenidone (Pirf), an FDA-approved pulmonary anti-fibrotic drug, is poorly tolerated and exhibits limited efficacy. Trigonelline (Trig) is a natural plant alkaloid with diverse pharmacological actions. We investigated the underlying prophylactic and therapeutic mechanisms of Trig in ameliorating bleomycin (BLM)-induced PF and the possible synergistic antifibrotic activity of Pirf via its combination with Trig. MATERIALS AND METHODS: A single dose of BLM was administered intratracheally to male Sprague-Dawley rats for PF induction. In the prophylactic study, Trig was given orally 3 days before BLM and then for 28 days. In the therapeutic study, Trig and/or Pirf were given orally from day 8 after BLM until the 28th day. Biochemical assay, histopathology, qRT-PCR, ELISA, and immunohistochemistry were performed on lung tissues. KEY FINDINGS: Trig prophylactically and therapeutically mitigated the inflammatory process via targeting NF-κB/NLRP3/IL-1ß signaling. Trig activated the autophagy process which in turn attenuated alveolar epithelial cells apoptosis and senescence. Remarkably, Trig attenuated lung SPHK1/S1P axis and its downstream Hippo targets, YAP-1, and TAZ, with a parallel decrease in YAP/TAZ profibrotic genes. Interestingly, Trig upregulated lung miR-375 and miR-27a expression. Consequently, epithelial-mesenchymal transition in lung tissues was reversed upon Trig administration. These results were simultaneously associated with profound improvement in lung histological alterations. SIGNIFICANCE: The current study verifies Trig's prophylactic and antifibrotic effects against BLM-induced PF via targeting multiple signaling. Trig and Pirf combination may be a promising approach to synergize Pirf antifibrotic effect.

Cinnamic acid mitigates methotrexate-induced lung fibrosis in rats: comparative study with pirfenidone.

PURPOSE: Lung fibrosis is a heterogeneous lung condition characterized by excessive accumulation of scarred tissue, leading to lung architecture destruction and restricted ventilation. The current work was conducted to examine the probable shielding influence of cinnamic acid against lung fibrosis induced by methotrexate. METHODS: Rats were pre-treated with oral administration of cinnamic acid (50 mg/kg/day) for 14 days, whereas methotrexate (14 mg/kg) was orally given on the 5th and 12th days of the experiment. Pirfenidone (50 mg/kg/day) was used as a standard drug. At the end of the experiment, oxidative parameters (malondialdehyde, myeloperoxidase, nitric oxide, and total glutathione) and inflammatory mediators (tumor necrosis factor-α and interleukin-8), as well as transforming growth factor-ß and collagen content, as fibrosis indicators, were measured in lung tissue. RESULTS: Our results revealed that cinnamic acid, as pirfenidone, effectively prevented the methotrexate-induced overt histopathological damage. This was associated with parallel improvements in oxidative, inflammatory, and fibrotic parameters measured. The outcomes of cinnamic acid administration were more or less the same as those of pirfenidone. In conclusion, pre-treatment with cinnamic acid protects against methotrexate-induced fibrosis, making it a promising prophylactic adjuvant therapy to methotrexate and protecting against its possible induction of lung fibrosis.

Glycyrrhetinic Acid Mitigates Radiation-Induced Pulmonary Fibrosis via Inhibiting the Secretion of TGF-ß1 by Treg Cells.

PURPOSE: Radiation-induced pulmonary fibrosis (RIPF) is a common side effect of radiation therapy for thoracic tumors without effective prevention and treatment methods at present. The aim of this study was to explore whether glycyrrhetinic acid (GA) has a protective effect on RIPF and the underlying mechanism. METHODS AND MATERIALS: A RIPF mouse model administered GA was used to determine the effect of GA on RIPF. The cocultivation of regulatory T (Treg) cells with mouse lung epithelial-12 cells or mouse embryonic fibroblasts and intervention with GA or transforming growth factor-ß1 (TGF-ß1) inhibitor to block TGF-ß1 was conducted to study the mechanism by which GA alleviates RIPF. Furthermore, injection of Treg cells into GA-treated RIPF mice to upregulate TGF-ß1 levels was performed to verify the roles of TGF-ß1 and Treg cells. RESULTS: GA intervention improved the damage to lung tissue structure and collagen deposition and inhibited Treg cell infiltration, TGF-ß1 levels, epithelial mesenchymal transition (EMT), and myofibroblast (MFB) transformation in mice after irradiation. Treg cell-induced EMT and MFB transformation in vitro were prevented by GA, as well as a TGF-ß1 inhibitor, by decreasing TGF-ß1. Furthermore, reinfusion of Treg cells upregulated TGF-ß1 levels and exacerbated RIPF in GA-treated RIPF mice. CONCLUSIONS: GA can improve RIPF in mice, and the corresponding mechanisms may be related to the inhibition of TGF-ß1 secreted by Treg cells to induce EMT and MFB transformation. Therefore, GA may be a promising therapeutic candidate for the clinical treatment of RIPF.

Histone deacetylase 3 deletion in alveolar type 2 epithelial cells prevents bleomycin-induced pulmonary fibrosis.

BACKGROUND: Epithelial mesenchymal transformation (EMT) in alveolar type 2 epithelial cells (AT2) is closely associated with pulmonary fibrosis (PF). Histone deacetylase 3 (HDAC3) is an important enzyme that regulates protein stability by modulating the acetylation level of non-histones. Here, we aimed to explore the potential role and regulatory mechanisms associated with HDAC3 in PF. METHODS: We quantified HDAC3 expression both in lung tissues from patients with PF and from bleomycin (BLM)-treated mice. HDAC3 was also detected in TGF-ß1-treated AT2. The mechanistic activity of HDAC3 in pulmonary fibrosis and EMT was also explored. RESULTS: HDAC3 was highly expressed in lung tissues from patients with PF and bleomycin (BLM)-treated mice, especially in AT2. Lung tissues from AT2-specific HDAC3-deficient mice stimulated with BLM showed alleviative fibrosis and EMT. Upstream of HDAC3, TGF-ß1/SMAD3 directly promoted HDAC3 transcription. Downstream of HDAC3, we also found that genetic or pharmacologic inhibition of HDAC3 inhibited GATA3 expression at the protein level rather than mRNA. Finally, we found that intraperitoneal administration of RGFP966, a selective inhibitor of HDAC3, could prevent mice from BLM-induced pulmonary fibrosis and EMT. CONCLUSION: TGF-ß1/SMAD3 directly promoted the transcription of HDAC3, which aggravated EMT in AT2 and pulmonary fibrosis in mice via deacetylation of GATA3 and inhibition of its degradation. Our results suggest that targeting HDAC3 in AT2 may provide a new therapeutic target for the prevention of PF.

Baicalin alleviates bleomycin-induced early pulmonary fibrosis in mice via the mitoKATP signaling pathway.

Bleomycin (BLM), a frequently employed chemotherapeutic agent, exhibits restricted clinical utility owing to its pulmonary toxicity. Meanwhile, baicalin (BA)-an active ingredient extracted from the roots of Scutellaria baicalensis Georgi -has been shown to alleviate BLM-induced pulmonary fibrosis (PF). Hence, the objective of this study was to examine the protective effects of BA in the context of BLM-induced early PF in mice and elucidate the underlying mechanism(s). We established an in vivo BLM (3.5 mg/kg)-induced PF murine model and in vitro BLM (35 µM)-damaged MLE-12 cell model. On Day 14 of treatment, the levels of fibrosis and apoptosis were evaluated in mouse lungs via hydroxyproline analysis, western blotting (COL1A1, TGF-ß, Bax, Bcl-2, cleaved caspase-3), and Masson, immunohistochemical (α-SMA, AIF, Cyto C), and TUNEL staining. Additionally, in vitro, apoptosis was assessed in MLE-12 cells exposed to BLM for 24 h using the Annexin V/PI assay and western blotting (Bax, Bcl-2, cleaved caspase-3, AIF, Cyto C). To elucidate the role of the mitochondrial ATP-sensitive potassium channel (mitoKATP) in the protective effect of BA, we utilised diazoxide (DZX)-a mitoKATP agonist-and 5-hydroxydecanoate sodium (5-HD)-a mitoKATP inhibitor. Results revealed the involvement of mitoKATP in the protective effect of BA in BLM-induced PF. More specifically, mitoKATP activation can attenuate BLM-induced PF progression and mitigate alveolar epithelial type II cell death by reducing mitochondrial ROS, maintaining the mitochondrial membrane potential, and impeding the mitochondrial apoptotic pathway. Collectively, the findings offer pharmacological support to use BA for the treatment or prevention of BLM-induced PF and suggest that mitoKATP might serve as an effective therapeutic target for this condition.

CD5L Deficiency Protects Mice Against Bleomycin-Induced Pulmonary Fibrosis.

BACKGROUND: Pulmonary fibrosis (PF), the most common clinical type of irreversible interstitial lung disease with one of the worse prognoses, has a largely unknown molecular mechanisms that underlies its progression. CD5 molecule-like (CD5L) functions in an indispensable role during inflammatory responses; however, whether CD5L functions in regulating bleomycin (BLM)-induced lung fibrosis is less clear. METHODS: Herein, we describe the engineering of Cd5l knockout mice using CRISPR/Cas9 gene editing technology. The BLM-induced model of acute lung injury represents the most widely used experimental rodent model for PF. RESULTS: Taking advantage of this model, we demonstrated that both CD5L mRNA and protein were enriched in the lungs of mice following BLM-induced pulmonary fibrosis. Inhibition of CD5L prevented mice from BLM-induced lung fibrosis and injury. In particular, a lack of CD5L significantly attenuated inflammatory response and promoted M2 polarization in the lung of this pulmonary fibrosis model as well as suppressing macrophage apoptosis. CONCLUSIONS: Collectively, our data support that CD5L deficiency can suppress the development of pulmonary fibrosis, and also provides new molecular targets for the use of immunotherapy to treat lung fibrosis.

Potential Therapeutic Targets of Resveratrol in the Prevention and Treatment of Pulmonary Fibrosis.

Pulmonary fibrosis (PF) is a feared component in over 200 interstitial pulmonary diseases, which are characterized by increased alveolar wall thickness, excessive scarring, and aberrant extracellular matrix restructuring that, ultimately, affect lung compliance and capacity. As a result of its broad range of biological activities, including antioxidant, anti-inflammatory, antiapoptotic, and many others, resveratrol has been shown to be an effective treatment for respiratory system diseases, including interstitial lung disease, infectious diseases, and lung cancer. This work reviews the known molecular therapeutic targets of resveratrol and its potential mechanisms of action in attenuating PF in respiratory diseases, including cancer, COVID-19, interstitial lung diseases (ILDs) of known etiologies, idiopathic interstitial pneumonia, and ILDs associated with systemic disorders, such as rheumatoid arthritis, systemic sclerosis, Schrödinger's syndrome, systemic lupus erythematosus, and pulmonary hypertension. The current issues and controversies related to the possible use of resveratrol as a pharmaceutical drug or supplement are also discussed.

Paroxetine protects against bleomycin-induced pulmonary fibrosis by blocking GRK2/Smad3 pathway.

G protein-coupled receptor kinase-2 (GRK2) is involved in TGF-ß1-induced activation of lung fibroblasts, which could give rise to the pathogenesis of pulmonary fibrosis. Paroxetine (PRXT) serves as a selective GRK2 inhibitor which is widely used to treat anxiety and depression for several decades. However, whether PRXT could inhibit TGF-ß1-induced activation of lung fibroblasts and combat bleomycin-induced pulmonary fibrosis remains unclear. Here, we investigated the effects of PRXT on pulmonary fibrosis in C57/BL6 caused by bleomycin as well as on the activation of murine primary lung fibroblasts stimulated with TGF-ß1. The results demonstrated that PRXT markedly improved the pulmonary function and 21-day survival in bleomycin-induced mice. Meanwhile, PRXT significantly decreased collagen deposition, inflammation, and oxidative stress in lung tissues from bleomycin-induced mice. Furthermore, we found that PRXT could inhibit the protein and mRNA expression of GRK2 and Smad3 in lung tissues from bleomycin-induced mice. In vitro experiments also PRXT could inhibit cell activation and collagen synthesis in a concentration-dependent manner in TGF-ß1-induced lung fibroblasts. In addition, we found that Smad3 overexpression by adenovirus transfection could offset anti-fibrotic and antioxidative effects from PRXT in TGF-ß1-induced lung fibroblasts, which showed no effects on the protein expression of GRK2. In conclusion, PRXT mediates the inhibition of GRK2, which further blocks the transcription of Smad3 in TGF-ß1-induced lung fibroblasts, providing an attractive therapeutic target for pulmonary fibrosis.

Astragaloside IV protects against lung injury and pulmonary fibrosis in COPD by targeting GTP-GDP domain of RAS and downregulating the RAS/RAF/FoxO signaling pathway.

BACKGROUND: Pulmonary fibrosis is a chronic progressive interstitial lung disease characterized by the replacement of lung parenchyma with fibrous scar tissue, usually as the final stage of lung injury like COPD. Astragaloside IV (AST), a bioactive compound found in the Astragalus membranaceus (Fisch.) used in traditional Chinese medicine, has been shown to improve pulmonary function and exhibit anti-pulmonary fibrosis effects. However, the exact molecular mechanisms through which it combats pulmonary fibrosis, especially in COPD, remain unclear. PURPOSE: This study aimed to identify the potential therapeutic target and molecular mechanisms for AST in improving lung injury especially treating COPD type pulmonary fibrosis both in vivo and in vitro. METHODS: Multi lung injury models were established in mice using lipopolysaccharide (LPS), cigarette smoke (CS), or LPS plus CS to simulate the processes of pulmonary fibrosis in COPD. The effect of AST on lung function protection was evaluated, and proteomic and metabolomic analysis were applied to identify the signaling pathway affected by AST and to find potential targets of AST. The interaction between AST and wild-type and mutant RAS proteins was studied. The RAS/RAF/FoxO signaling pathway was stimulated in BEAS-2B cells and in mice lung tissues by LPS plus CS to investigate the anti-pulmonary fibrosis mechanism of AST analyzed by western blotting. The regulatory effects of AST on the RAS/RAF/FoxO pathway dependent on RAS were further confirmed using RAS siRNA. RESULTS: RAS was predicted and identified as the target protein of AST in anti-pulmonary fibrosis in COPD and improving lung function. The administration of AST was observed to impede the conversion of fibroblasts into myofibroblasts, reduce the manifestation of inflammatory factors and extracellular matrix, and hinder the activation of epithelial mesenchymal transition (EMT). Furthermore, AST significantly suppressed the RAS/RAF/FoxO signaling pathway in both in vitro and in vivo settings. CONCLUSION: AST exhibited lung function protection and anti-pulmonary fibrosis effect by inhibiting the GTP-GDP domain of RAS, which downregulated the RAS/RAF/FoxO signaling pathway. This study revealed AST as a natural candidate molecule for the protection of pulmonary fibrosis in COPD.

TLR4/ MyD88/NF-κB signaling pathway involved in the protective effect of diacerein against lung fibrosis in rats.

PURPOSE: Pulmonary fibrosis (PF) is an inescapable problem. Diacerein, a chondro-protective drug, has antioxidant and anti-inflammatory effects. Its effect on PF injury has not yet been fully clarified. Therefore, the current study aimed to detect its protective effect on lung tissue with the explanation of possible underlying mechanisms. METHODS: Adult male albino rats were assigned to four groups: control group, diacerein control group, PF non-treated group, and PF diacerein pretreated group. Lung tissue oxidative stress parameters, inflammatory biomarkers mainly Toll-like receptors-4 (TLR4), and myeloid differentiation factor 88 (MyD88) levels were determined. Histopathological examination of lung tissue and immunohistochemical studies of nuclear factor-kappa B (NF-κB), and transforming growth factor- ß (TGF-ß) were also done. RESULTS: Diacerein pretreatment has the ability to restore the PF damaging effect, proved by the reduction of the oxidative stress and lung tissue inflammation via downregulation of TLR4/NF-κB signaling pathway together with the restoration of TGF-ß level and improvement of the histopathological and immunohistochemical study findings in the lung tissue. CONCLUSION: These results suggested the protective effect of diacerein on PF relies on its antioxidant and anti-inflammatory effects reducing TLR4/NF-κB signaling pathway.

Prolyl oligopeptidase inhibition ameliorates experimental pulmonary fibrosis both in vivo and in vitro.

BACKGROUND: Pulmonary fibrosis is a progressive disease characterized by lung remodeling due to excessive deposition of extracellular matrix. Although the etiology remains unknown, aberrant angiogenesis and inflammation play an important role in the development of this pathology. In this context, recent scientific research has identified new molecules involved in angiogenesis and inflammation, such as the prolyl oligopeptidase (PREP), a proteolytic enzyme belonging to the serine protease family, linked to the pathology of many lung diseases such as pulmonary fibrosis. Therefore, the aim of this study was to investigate the effect of a selective inhibitor of PREP, known as KYP-2047, in an in vitro and in an in vivo model of pulmonary fibrosis. METHODS: The in vitro model was performed using human alveolar A549 cells. Cells were exposed to lipopolysaccharide (LPS) 10 µg/ml and then, cells were treated with KYP-2047 at the concentrations of 1 µM, 10 µM and 50 µM. Cell viability was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium (MTT) bromide colorimetric assay, while inflammatory protein expression was assessed by western blots analysis. The in vivo model was induced in mice by intra-tracheal administration of bleomycin (1 mg/kg) and then treated intraperitoneally with KYP-2047 at doses of 1, 2.5 and 5 mg/kg once daily for 12 days and then mice were sacrificed, and lung tissues were collected for analyses. RESULTS: The in vitro results demonstrated that KYP-2047 preserved cell viability, reduced inflammatory process by decreasing IL-18 and TNF-α, and modulated lipid peroxidation as well as nitrosative stress. The in vivo pulmonary fibrosis has demonstrated that KYP-2047 was able to restore histological alterations reducing lung injury. Our data demonstrated that KYP-2047 significantly reduced angiogenesis process and the fibrotic damage modulating the expression of fibrotic markers. Furthermore, KYP-2047 treatment modulated the IκBα/NF-κB pathway and reduced the expression of related pro-inflammatory enzymes and cytokines. Moreover, KYP-2047 was able to modulate the JAK2/STAT3 pathway, highly involved in pulmonary fibrosis. CONCLUSION: In conclusion, this study demonstrated the involvement of PREP in the pathogenesis of pulmonary fibrosis and that its inhibition by KYP-2047 has a protective role in lung injury induced by BLM, suggesting PREP as a potential target therapy for pulmonary fibrosis. These results speculate the potential protective mechanism of KYP-2047 through the modulation of JAK2/STAT3 and NF-κB pathways.

N-Acetylglucosamine mitigates lung injury and pulmonary fibrosis induced by bleomycin.

Lung injury and pulmonary fibrosis contribute to morbidity and mortality, and, in particular, are characterized as leading cause on confirmed COVID-19 death. To date, efficient therapeutic approach for such lung diseases is lacking. N-Acetylglucosamine (NAG), an acetylated derivative of glucosamine, has been proposed as a potential protector of lung function in several types of lung diseases. The mechanism by which NAG protects against lung injury, however, remains unclear. Here, we show that NAG treatment improves pulmonary function in bleomycin (BLM)-induced lung injury model measured by flexiVent system. At early phase of lung injury, NAG treatment results in silenced immune response by targeting ARG1+ macrophages activation, and, consequently, blocks KRT8+ transitional stem cell in the alveolar region to stimulate PDGF Rß+ fibroblasts hyperproliferation, thereby attenuating the pulmonary fibrosis. This combinational depression of immune response and extracellular matrix deposition within the lung mitigates lung injury and pulmonary fibrosis induced by BLM. Our findings provide novel insight into the protective role of NAG in lung injury.

CD45 alleviates airway inflammation and lung fibrosis by limiting expansion and activation of ILC2s.

Group 2 innate lymphoid cells (ILC2s) are critical for the immune response against parasite infection and tissue homeostasis and involved in the pathogenesis of allergy and inflammatory diseases. Although multiple molecules positively regulating ILC2 development and activation have been extensively investigated, the factors limiting their population size and response remain poorly studied. Here, we found that CD45, a membrane-bound tyrosine phosphatase essential for T cell development, negatively regulated ILC2s in a cell-intrinsic manner. ILC2s in CD45-deficient mice exhibited enhanced proliferation and maturation in the bone marrow and hyperactivated phenotypes in the lung with high glycolytic capacity. Furthermore, CD45 signaling suppressed the type 2 inflammatory response by lung ILC2s and alleviated airway inflammation and pulmonary fibrosis. Finally, the interaction with galectin-9 influenced CD45 signaling in ILC2s. These results demonstrate that CD45 is a cell-intrinsic negative regulator of ILC2s and prevents lung inflammation and fibrosis via ILC2s.

Atractylodinol prevents pulmonary fibrosis through inhibiting TGF-ß receptor 1 recycling by stabilizing vimentin.

Pirfenidone and nintedanib are only anti-pulmonary fibrosis (PF) drugs approved by the FDA. However, they are not target specific, and unable to modify the disease status. Therefore, it is still desirable to discover more effective agents against PF. Vimentin (VIM) plays key roles in tissue regeneration and wound healing, but its molecular mechanism remains unknown. In this work, we demonstrated that atractylodinol (ATD) significantly inhibits TGF-ß1-induced epithelial-mesenchymal transition and fibroblast-to-myofibroblast transition in vitro. ATD also reduces bleomycin-induced lung injury and fibrosis in mice models. Mechanistically, ATD inhibited TGF-ß receptor I recycling by binding to VIM (KD = 454 nM) and inducing the formation of filamentous aggregates. In conclusion, we proved that ATD (derived from Atractylodes lancea) modified PF by targeting VIM and inhibiting the TGF-ß/Smad signaling pathway. Therefore, VIM is a druggable target and ATD is a proper drug candidate against PF. We prove a novel VIM function that TGF-ß receptor I recycling. These findings paved the way to develop new targeted therapeutics against PF.

Incomplete Knockdown of MyD88 Inhibits LPS-Induced Lung Injury and Lung Fibrosis in a Mouse Model.

Acute lung injury (ALI) is a life-threatening disorder stemmed mainly from an uncontrolled inflammatory response. Lipopolysaccharide (LPS) is commonly used to induce ALI animal models. Toll-like receptor 4 (TLR4) is the main receptor for LPS, and myeloid differentiation factor 88 (MyD88) is a key adaptor protein molecule in the Toll-like receptor (TLR) signaling pathway. Thus, MyD88 knockdown heterozygous mice (MyD88+/-) were used to investigate the effect of incomplete knockout of the MyD88 gene on indirect LPS-induced ALI through intraperitoneal injection of LPS. The LPS-induced ALI significantly upregulated MyD88 expression, and heterozygous mice with incomplete knockout of the MyD88 gene (MyD88+/-) ameliorated LPS-induced histopathological injury and collagen fiber deposition. Heterozygous mice with incomplete knockout of the MyD88 gene (MyD88+/-) inhibited LPS-induced nuclear factor-κB (NF-κB) pathway activation, but TLR-4 expression tended to be upregulated. Incomplete knockdown of the MyD88 gene also downregulated LPS-induced expression of IL1-ß, IL-6, TNF-α, TGF-ß, SMAD2, and α-SMA. The transcriptome sequencing also revealed significant changes in LPS-regulated genes (such as IL-17 signaling pathway genes) after the incomplete knockdown of MyD88. In conclusion, this paper clarified that LPS activates the downstream NF-κB pathway depending on the MyD88 signaling pathway, which induces the secretion of inflammatory cytokines such as IL-1ß/IL-6/TNF-α and ultimately triggers ALI. Incomplete knockdown of the MyD88 reverses LPS-induced lung fibrosis, which confirmed the vital role of MyD88 in LPS-induced ALI.

[Radiation-induced pulmonary fibrosis: New potential targets]. / Fibrose pulmonaire radio-induite : nouvelles cibles pour demain.

Radiation-induced pulmonary fibrosis (RIPF) is one of the major and late complications of radiotherapy (RT) with an average incidence rate between 16 and 28% after RT. RIPF significantly affects the function of the affected tissues/organs as well as the quality of life and survival of patients. The process of radiation fibrogenesis is initiated by a very complex signaling network that involves several cellular and molecular factors and the development of effective treatments relies on a better understanding of the involved mechanisms. Despite a major advance in the field, to date there is no clinical treatment that has really shown efficacy in the prevention or treatment of RIPF. In the present review, we will discuss potential new therapeutic avenues that could effectively treat RIPF.