Mouse Lung Research Articles

Coinhibitory Molecule VISTA Play an Important Negative Regulatory Role in the Immunopathology of Bronchial Asthma.

To investigatethesignificanceofVISTAinbronchialasthma and its impact on the disease. Human peripheral blood of asthma children was gathered. The expressionconcentrationsofVISTA,IL-4,IL-6,CD25,CD40L,andPD-L2 in peripheral blood plasma were detected by ELISA. We established the mouse model of asthma and intervened with agonistic anti-VISTAmAb(4C11) and VISTA fusion protein. ELISA, flow cytometry, and Western blottingwereperformed todetectthe expressionlevels ofTh1,Th2,and Th17 cell subsets and related characteristic cytokines, as well as the protein levels of MAPKs, NF-κB, and TRAF6 in lung tissues. In addition, the infiltration of eosinophils and inflammatory cells, airway mucus secretion, and VISTA protein expression in lung histopathological sections of different groups of mice were analyzed. The concentration of VISTA in human asthma group decreased significantly (p < 0.05); A positive correlation was observed between VISTA and CD40L. The intervention of 4C11mAband fusion protein respectively during the induction period increase the differentiation of Th1cellsandthesecretionofIFN-γ,andinhibitthedifferentiationofTh2 and Th17cells, aswell as the secretion of IL-4, IL-5, IL-13 and IL-17, partially reduce the pathological changes of asthma in mouse lungs and correct the progress of asthma. The MAPK, NF-κB, and TRAF6 protein levels were the middle rangein the4C11mAbandfusion proteingroups (p < 0.05). ThefindingssuggestVISTAmayplayanegativeregulatory role in the occurrence and development of bronchial asthma.

The Effects of High-Fat Diet and Flaxseed Oil-Enriched Diet on the Lung Parenchyma of Obese Mice.

Omega-3 (ω3) fatty acids are widely investigated for their anti-inflammatory potential, however, there is little evidence regarding their action in the lung parenchyma in the context of obesity. The objective is to investigate the effects of flaxseed oil (FS), rich in α-linolenic (C18:3 - ω3), on the lungs of obese mice. Mice were fed a high-fat diet (HF) for 8 weeks to induce obesity. Subsequently, a part of these animals received HF containing FS oil for another 8 weeks. The HF consumption induced weight gain and hyperglycemia. The lung parenchyma shows a complete fatty acids profile, compared to the control group (CT). In the lung parenchyma, FS increases the ω3 content and, notwithstanding a reduction in the interleukins (IL) IL1β and IL18 contents compared to HF. However, FS promotedincreased alveolar spaces, followed by MCP1 (Monocytes Chemoattractant Protein-1) positive cell infiltration and a dramatic reduction in the anti-inflammatory cytokine, IL10. Despite reducing the pulmonary inflammatory response, the consumption of a food source of ω3 was associated with alterations in the lipid profile and histoarchitecture of the lung parenchyma, which can lead to the development of pulmonary complications. This study brings an alert against the indiscriminate use of ω3 supplements, warranting caution.

A combined treatment with Ursolic acid and Solasodine inhibits colorectal cancer progression through the AKT1/ERK1/2-GSK-3β-β-catenin axis

BackgroundConventional chemotherapy medications are inadequate for managing the primary or acquired drug resistance, high toxicity, and adverse effects of colorectal cancer (CRC) treatment. Ursolic acid (UA) and Solasodine (Sol) are natural compounds found in a wide variety of traditional medicinal plants, as well as in many fruits and vegetables, such as Actinidia arguta (Sieb. & Zucc) Planch and Solanum nigrum L.. These compounds exhibit significant anti-tumor activity. Recent investigations have demonstrated that a combination strategy using natural products exhibits greater potential in CRC treatment compared to a single-drug strategy. PurposeThis study aimed to elucidate the potential of UA-Sol synergy against CRC and to investigate the mechanism of action involved in inducing apoptosis and inhibiting metastasis through the AKT1/ERK1/2-GSK-3β-β-catenin axis. MethodsThe optimal ratio of UA-Sol and its synergistic effects were explored using an MTT assay combined with the technique of Chou Talalay. The effects of UA-Sol on the apoptosis, autophagy, and metastasis of CRC cells were assessed using Annexin V-FITC/PI, TUNEL, Immunofluorescence, Wound healing, Transwell migration, and western blotting. The core mechanism of action of UA-Sol against CRC was investigated employing network pharmacology prediction combined with CETSA and plasmid transfection. Finally, in vivo validation was conducted using mouse xenograft tumor and lung metastasis models. ResultsThe combination of UA and Sol synergistically inhibited CRC cell viability at a molar ratio of 6:24. UA-Sol induced the expression of pro-apoptotic and autophagy genes such as Bax/Bcl-2 and LC3, ultimately leading to apoptosis and autophagy in CRC cells in vitro. In addition, this combination inhibited MMP-9 and promoted the expression of the adhesion protein E-cadherin, thereby inhibiting CRC cell metastasis. Mechanistically, UA-Sol regulated the expression of a downstream protein GSK-3β by targeting AKT1 and ERK1/2 inhibition. This induced a cross-talk between the MAPK cascade pathway and the PI3K/AKT pathway, thereby inhibiting the nuclear translocation of β-catenin and participating in the regulation of CRC cell processes. ConclusionUA-Sol inhibited the AKT1/ERK1/2-GSK-3β-β-catenin axis to induce apoptosis, autophagy and anti-metastasis by targeting AKT1 and ERK1/2 inhibition. This dual-target drug combination strategy provides promising insights into the development of novel, safe, and efficient drugs for the treatment of CRC.

Linoleic Acid Promotes Mitochondrial Biogenesis and Alleviates Acute Lung Injury.

Acute lung injury (ALI) is a critical and lethal medical condition. This syndrome is characterized by an imbalance in the body's oxidation stress and inflammation. Linoleic acid (LA), a polyunsaturated fatty acid, has been extensively studied for its potential health benefits, including anti-inflammatory and antioxidant activities. However, the therapeutic effects of LA on ALI remain unexplored. Lipopolysaccharide (LPS), found in gram-negative bacteria's outer membrane, was intraperitoneally injected to induce ALI in mice. Invitro model was established by LPS stimulation of mouse lung epithelial 12 (MLE-12) cells. LA treatment demonstrated a significant amelioration in LPS-induced hypothermia, poor state, and pulmonary injury in mice. LA treatment resulted in a reduction in the concentration of bronchoalveolar lavage fluid (BALF) protein and an increase in myeloperoxidase (MPO) activity in LPS-induced mice. LA treatment reduced the generation of white blood cells. LA treatment reduced cell-free (cfDNA) release and promote adenosine triphosphate (ATP) production. LA increased the levels of superoxide dismutase (SOD) and glutathione (GSH) but decreased the production of malondialdehyde (MDA). LA treatment enhanced mitochondrial membrane potential. LA attenuated LPS-induced elevations of inflammatory cytokines in both mice and cells. Additionally, LA exerted its protective effect against LPS-induced damage through activation of the peroxisome proliferator-activated receptor γ coactivator l alpha (PGC-1α)/nuclear respiratory factor 1 (NRF1)/transcription factor A of the mitochondrion (TFAM) pathway. LA may reduce inflammation and stimulate mitochondrial biogenesis in ALI mice and MLE-12 cells.

Evidence of Alveolar Macrophage Metabolic Shift Following Stereotactic Body Radiation Therapy -Induced Lung Fibrosis in Mice

Radiation-induced pneumopathy is the main dose-limiting factor in cases of chest radiation therapy. Macrophage infiltration is frequently observed in irradiated lung tissues and may participate in lung damage development. Radiation-induced lung fibrosis can be reproduced in rodent models using whole thorax irradiation but suffers from limits concerning the role played by unexposed lung volumes in damage development. Here, we used an accurate stereotactic body radiation therapy preclinical model irradiating 4% of the mouse lung. Tissue damage development and macrophage populations were followed by histology, flow cytometry, and single-cell RNA sequencing. Wild-type and CCR2 KO mice, in which monocyte recruitment is abrogated, were exposed to single doses of radiation, inducing progressive (60 Gy) or rapid (80 Gy) lung fibrosis. Numerous clusters of macrophages were observed around the injured area, during progressive as well as rapid fibrosis. The results indicate that probably CCR2-independent recruitment and/or in situ proliferation may be responsible for macrophage invasion. Alveolar macrophages experience a metabolic shift from fatty acid metabolism to cholesterol biosynthesis, directing them through a possible profibrotic phenotype. Depicted data revealed that the origin and phenotype of macrophages present in the injured area may differ from what has been previously described in preclinical models exposing large lung volumes, representing a potentially interesting trail in the deciphering of radiation-induced lung damage processes. Our study brings new possible clues to the understanding of macrophage implications in radiation-induced lung damage, representing an interesting area for exploration in future studies.

Combined Chemo- and Photothermal Therapies of Non-Small Cell Lung Cancer Using Polydopamine/Au Hollow Nanospheres Loaded with Doxorubicin.

The chemotherapeutic agent doxorubicin (DOX) is limited by its cardiotoxicity, posing challenges in its application for non-small cell lung cancer (NSCLC). This study aims to explore the efficacy of polydopamine/Au nanoparticles loaded with DOX for chemotherapy and photothermal therapy in NSCLC to achieve enhanced efficacy and reduced toxicity. Hollow polydopamine (HPDA)/Au@DOX was synthesized via polydopamine chemical binding sacrificial template method. Morphology was characterized using transmission electron microscopy, particle size and potential were determined using dynamic light scattering, and photothermal conversion efficiency was assessed using near-infrared (NIR) thermal imaging. Drug loading rate and in vitro drug release were investigated. In vitro, anti-tumor experiments were conducted using CCK-8 assay, flow cytometry, and live/dead cell staining to evaluate the cytotoxicity of HPDA/Au@DOX on A549 cells. Uptake of HPDA/Au@DOX by A549 cells was detected using the intrinsic fluorescence of DOX. The in vivo anti-metastasis and anti-tumor effects of HPDA/Au@DOX were explored in mouse lung metastasis and subcutaneous tumor models, respectively. HPDA/Au@DOX with a particle size of (164.26±3.25) nm, a drug loading rate of 36.31%, and an encapsulation efficiency of 90.78% was successfully prepared. Under 808 nm laser irradiation, HPDA/Au@DOX accelerated DOX release and enhanced uptake by A549 cells. In vitro photothermal performance assessment showed excellent photothermal conversion capability and stability of HPDA/Au@DOX under NIR laser irradiation. Both in vitro and in vivo experiments demonstrated that the photothermal-chemotherapy combination group (HPDA/Au@DOX+NIR) exhibited stronger anti-metastatic and anti-tumor activities compared to the monotherapy group (DOX). HPDA/Au@DOX nanosystem demonstrated excellent photothermal effect, inhibiting the growth and metastasis of A549 cells. This nanosystem achieves the combined effect of chemotherapy and photothermal, making it promising for NSCLC treatment.

Shengmai Powder regulates alveolar macrophage PPAR-γ and improves the chronic inflammatory state of chronic obstructive pulmonary disease.

This study examines the therapeutic effects of Shengmai Powder (SMP) on both in vitro and in vivo models of chronic obstructive pulmonary disease (COPD) and the underlying mechanisms. Cigarette smoke and cigarette extracts were used to create in vitro and in vivo models of COPD. ELISA was used to measure the levels of pro-inflammatory factors (IL-6, TNF-α, and IL-1β) in mouse lung tissue and alveolar macrophages. Flow cytometry assessed the phagocytic capacity of alveolar macrophage. Western blotting was used to analyze the expression of RhoA, PPARγ, IκBα, p-IκBα, P65, and p-P65 in alveolar. The results show that SMP reversed the increased levels of pro-inflammatory factors (IL-6, TNF-α, and IL-1β) in mouse lung tissue and alveolar macrophages induced by cigarette smoke and cigarette extract. SMP also restored the decreased fluorescence intensity and RhoA levels in alveolar macrophages caused by cigarette extract. Additionally, SMP increased PPARγ expression and decreased IκBα and P65 phosphorylation in alveolar macrophages exposed to cigarette extract. Also, the effects of SMP were reversed by PPARγ inhibitors. The study concluded that SMP regulates alveolar macrophage phagocytic function through the PPAR-γ/NF-κB pathway, thereby improving the chronic inflammatory state of COPD.

Bone morphogenetic protein 4 ameliorates bleomycin-induced pulmonary fibrosis in mice by repressing NLRP3 inflammasome activation and epithelial-mesenchymal transition.

Idiopathic pulmonary fibrosis (IPF) is a progressive and deadly lung disease with limited therapeutic options. Bone morphogenetic protein 4 (BMP4), a multifunctional growth factor that belongs to the transforming growth factor-β superfamily, is able to relieve pulmonary fibrosis in mice; nevertheless, the potential mechanism of action remains largely unknown. Growing evidence supports the notion that reiterant damage to the alveolar epithelial cells (AECs) is usually the "prime mover" for pulmonary fibrosis. Here, we examined the effect and mechanisms of BMP4 on bleomycin (BLM)-induced activation of NLR family pyrin domain containing 3 (NLRP3) inflammasome and epithelial-mesenchymal transition (EMT) in vivo and in vitro. The in vivo impact of BMP4 was investigated in a BLM mouse model. Histopathologic changes were analyzed by hematoxylin-eosin (H&E) and Masson's trichrome staining. The NLRP3 inflammasome activation was determined by quantitative real time polymerase chain reaction (qRT-PCR) and immunofluorescence staining. Biomarkers of EMT were measured by qRT-PCR, Western blot and immunofluorescence staining. The in vitro impact of BMP4 on BLM-induced NLRP3 inflammasome activation and EMT was explored in A549 AECs. We also evaluated whether BMP4 inhibited BLM-activated ERK1/2 signaling to address the possible molecular mechanisms. BMP4 was significantly downregulated in the mouse lungs from BLM-induced pulmonary fibrosis. BMP4+/- mice presented with more severe lung fibrosis in response to BLM, and accelerated NLRP3 inflammasome activation and EMT process compared with that in BMP4+/+ mice. Whereas overexpression of BMP4 by injecting adeno-associated virus (AAV) 9 into mice attenuated BLM-induced fibrotic changes, NLRP3 inflammasome activation, and EMT in the mouse lungs, thus exerting protective efficacy against lung fibrosis. In vitro, BMP4 significantly reduced BLM-induced activation of NLRP3 inflammasome and EMT in human alveolar epithelial A549 cells. Mechanically, BMP4 repressed BLM-induced activation of ERK1/2 signaling in vivo and in vitro, suggesting that ERK1/2 inactivation contributes to BMP4-induced effects on BLM-induced activation of NLRP3 inflammasome and EMT. Our findings suggest that BMP4 can suppress NLRP3 inflammasome activation and EMT in AECs via inhibition of ERK1/2 signaling pathway, thus has a potential for the treatment of pulmonary fibrosis.

Gammaherpesvirus Infection Stimulates Lung Tumor-Promoting Inflammation.

Lung tumor-promoting environmental exposures and γherpesvirus infections are associated with Type 17 inflammation. To test the effect of γherpesvirus infection in promoting lung tumorigenesis, we infected mutant K-Ras-expressing (K-RasLA1) mice with the murine γherpesvirus MHV68 via oropharyngeal aspiration. After 7 weeks, the infected mice displayed a more than 2-fold increase in lung tumors relative to their K-RasLA1 uninfected littermates. Assessment of cytokines in the lung revealed that expression of Type 17 cytokines (Il-6, Cxcl1, Csf3) peaked at day 7 post-infection. These observations correlated with the post-infection appearance of known immune mediators of tumor promotion via IL-17A in the lungs of tumor-bearing mice. Surprisingly, Cd84, an immune cell marker mRNA, did not increase in MHV68-infected wild-type mice lacking lung tumors. Csf3 and Cxcl1 protein levels increased more in the lungs of infected K-RasLA1 mice relative to infected wild-type littermates. Flow cytometric and transcriptomic analyses indicated that the infected K-RasLA1 mice had increased Ly6Gdim/Ly6Chi immune cells in the lung relative to levels seen in uninfected control K-RasLA1 mice. Selective methylation of adenosines (m6A modification) in immune-cell-enriched mRNAs appeared to correlate with inflammatory infiltrates in the lung. These observations implicate γherpesvirus infection in lung tumor promotion and selective accumulation of immune cells in the lung that appears to be associated with m6A modification of mRNAs in those cells.

Immunogenicity and Protective Efficacy of a Multi-Antigen Mycobacterium tuberculosis Subunit Vaccine in Mice.

There is an urgent need for an effective TB vaccine capable of controlling both acute and chronic Mycobacterium tuberculosis infection in populations with diverse genetic backgrounds. In this study, we characterised the immunogenicity and protective efficacy of a novel protein-in-adjuvant subunit vaccine. The protein component is a fusion protein of three different M. tuberculosis antigens, which we termed CysVac5: CysD, a major component of the M. tuberculosis sulfate activation pathway that is highly expressed during the chronic stage of M. tuberculosis infection, is fused with two major secreted mycobacterial antigens, Ag85B and MPT83. Vaccination of C57BL/6 mice with CysVac5, formulated in a monophosphoryl lipid A (MPLA) and dimethyldioctadecylammonium (DDA) adjuvant combination, resulted in the potent generation of polyfunctional CD4+ T cells secreting multiple cytokines, including IFN-γ, IL-2, TNF and IL-17, against each of the three components of the fusion protein. Furthermore, vaccination with CysVac5-MPLA/DDA conferred significant protection against infection in mouse lungs, which was greater than that afforded by BCG at extended time points post-challenge. The generation of antigen-specific and protective immunity was also observed in CysVac5 vaccinated BALB/c mice, indicating the vaccine could display efficacy across multiple genetic backgrounds. These results indicate that the CysVac5 vaccine has broad immunogenicity, is effective in controlling both acute and chronic phases of M. tuberculosis infection in mice, and warrants further investigation to assess its potential to control pulmonary TB.

Macrophage targeted graphene oxide nanosystem synergize antibiotic killing and host immune defense for Tuberculosis Therapy

Tuberculosis (TB), a deadly disease caused by Mycobacterium tuberculosis (Mtb) infection, remains one of the top killers among infectious diseases worldwide. How to increase targeting effects of current anti-TB chemotherapeutics and enhance anti-TB immunological responses remains a big challenge in TB and drug-resistant TB treatment. Here, mannose functionalized and polyetherimide protected graphene oxide system (GO-PEI-MAN) was designed for macrophage-targeted antibiotic (rifampicin) and autophagy inducer (carbamazepine) delivery to achieve more effective Mtb killings by combining targeted drug killing and host immunological clearance. GO-PEI-MAN system demonstrated selective uptake by in vitro macrophages and ex vivo macrophages from macaques. The endocytosed GO-PEI-MAN system would be transported into lysosomes, where the drug loaded Rif@Car@GO-PEI-MAN system would undergo accelerated drug release in acidic lysosomal conditions. Rif@Car@GO-PEI-MAN could significantly promote autophagy and apoptosis in Mtb infected macrophages, as well as induce anti-bacterial M1 polarization of Mtb infected macrophages to increase anti-bacterial IFN-γ and nitric oxide production. Collectively, Rif@Car@GO-PEI-MAN demonstrated effectively enhanced intracellular Mtb killing effects than rifampicin, carbamazepine or GO-PEI-MAN alone in Mtb infected macrophages, and could significantly reduce mycobacterial burdens in the lung of infected mice with alleviated pathology and inflammation without systemic toxicity. This macrophage targeted nanosystem synergizing increased drug killing efficiency and enhanced host immunological defense may be served as more effective therapeutics against TB and drug-resistant TB.

Classical dendritic cells contribute to hypoxia-induced pulmonary hypertension.

Pulmonary hypertension (PH) is a chronic and progressive disease with significant morbidity and mortality. It is characterized by remodeled pulmonary vessels associated with perivascular and intravascular accumulation of inflammatory cells. Although there is compelling evidence that bone marrow-derived cells, such as macrophages and T cells, cluster in the vicinity of pulmonary vascular lesions in humans and contribute to PH development in different animal models, the role of dendritic cells in PH is less clear. Dendritic cells' involvement in PH is likely since they are responsible for coordinating innate and adaptive immune responses. We hypothesized that dendritic cells drive hypoxic PH. We demonstrate that a classical dendritic cell (cDC) subset (cDC2) is increased and activated in wild-type mouse lungs after hypoxia exposure. We observe significant protection after the depletion of cDCs in ZBTB46 DTR chimera mice before hypoxia exposure and after established hypoxic PH. In addition, we find that cDC depletion is associated with a reduced number of two macrophage subsets in the lung (FolR2+ MHCII+ CCR2+ and FolR2+ MHCII+ CCR2-). We found that depleting cDC2s, but not cDC1s, was protective against hypoxic PH. Finally, proof-of-concept studies in human lungs show increased perivascular cDC2s in patients with Idiopathic Pulmonary Arterial Hypertension (IPAH). Our data points to an essential role of cDCs, particularly cDC2s, in the pathophysiology of experimental PH.

High throughput screening of airway constriction in mouse lung slices

The level of airway constriction in thin slices of lung tissue is highly variable. Owing to the labor-intensive nature of these experiments, determining the number of airways to be analyzed in order to allocate a reliable value of constriction in one mouse is challenging. Herein, a new automated device for physiology and image analysis was used to facilitate high throughput screening of airway constriction in lung slices. Airway constriction was first quantified in slices of lungs from male BALB/c mice with and without experimental asthma that were inflated with agarose through the trachea or trans-parenchymal injections. Random sampling simulations were then conducted to determine the number of airways required per mouse to quantify maximal constriction. The constriction of 45 ± 12 airways per mouse in 32 mice were analyzed. Mean maximal constriction was 37.4 ± 32.0%. The agarose inflating technique did not affect the methacholine response. However, the methacholine constriction was affected by experimental asthma (p = 0.003), shifting the methacholine concentration–response curve to the right, indicating a decreased sensitivity. Simulations then predicted that approximately 35, 16 and 29 airways per mouse are needed to quantify the maximal constriction mean, standard deviation and coefficient of variation, respectively; these numbers varying between mice and with experimental asthma.

Inhibiting endothelial Rhoj blocks profibrotic vascular intussusception and angiocrine factors to sustain lung regeneration.

Lung regeneration after fibrosis requires formation of functional new vasculature, which is essential for gas exchange and cellular cross-talk with other lung cells. It remains unknown how the lung vasculature can be regenerated without fibrosis. Here, we tested the role of N6-methyladenosine (m6A) modification of forkhead box protein O1 (Foxo1) mRNA in lung regeneration after pneumonectomy (PNX) in mice, a model for lung regrowth after surgical resection. Endothelial cell (EC)-specific knockout of methyltransferase-like 3 (Mettl3) and Foxo1 caused nonproductive intussusceptive angiogenesis (IA), which impaired regeneration and enhanced fibrosis. This nonproductive IA was characterized by enhanced endothelial proliferation and increased vascular splitting with increased numbers of pillar ECs. Endothelial-selective knockout of Mettl3 in mice stimulated nonproductive IA and up-regulation of profibrotic factors after PNX, promoting regeneration to fibrotic transition. EC-specific mutation of m6A modification sites in the Foxo1 gene in mice revealed that endothelial Mettl3 modified A504 and A2035 sites in the Foxo1 mRNA to maintain pro-regenerative endothelial glycolysis, ensuring productive IA and lung regeneration without fibrosis. Suppression of Mettl3-Foxo1 signaling stimulated a subset of hyperglycolytic and hyperproliferative 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (Pfkfb3)+, Ras homolog family member J (Rhoj)+, and platelet-derived growth factor subunit B (Pdgfb)+ ECs in both human and mouse lungs with fibrosis. Inhibiting this Pfkfb3+Rhoj+Pdgfb+ EC subset normalized IA, alleviated fibrosis, and restored regeneration in bleomycin (BLM)-injured mouse lungs. We found that m6A modification of Foxo1 in the mouse vasculature promoted lung regeneration over fibrosis after PNX and BLM injury.

Melatonin prevents histopathologies stem from cadmium chloride in pregnant mice lungs.

Heavy metals may cause structural and functional changes in organs. Cadmium, taken into the body through oral and respiratory routes, can lead to lesions. Cadmium may lead to lesions by accumulating in organs. The lungs are significantly affected by cadmium. Melatonin, an antioxidant hormone with therapeutic effects, is secreted by the pineal gland. The aim of the study is to treat cadmium-induced lesions in the lungs of pregnant mice with Melatonin. Four groups were created with 24 pregnant mice, named Control, Cadmium Chloride, Melatonin, and Melatonin + Cadmium Chloride groups (n: 6) Cadmium Chloride (2mg/kg/bw) and Melatonin (3mg/kg/bw) were given orally through gavage during pregnancy (21 days) After routine histological procedures, the lung tissues were stained with Hematoxylin-Eosin and evaluated under a light and electron microscope. ANOVA tests were applied for one-way analysis of variance, and LSD tests were applied for pairwise comparisons (p < 0.05) The average lung weight decreased in the Cadmium Chloride group (p: 0.03) The average lung weight in the Cadmium Chloride + Melatonin group was found to be close to the control group (p: 0.06) Cadmium Chloride caused thickening of the lung alveolar wall, inflammatory cell infiltration, and fibrin deposition. Because the lesions were not observed in the Melatonin group, lesions may be prevented by melatonin. Additional studies may be useful to determine the protective effect of Melatonin at different doses of Cadmium Chloride.

MYOCD and SRF-mediated MLCK transcription prevents polymorphonuclear neutrophils from ferroptosis in sepsis-related acute lung injury.

Persistent activation of polymorphonuclear neutrophils (PMNs) plays a crucial role in the development of sepsis-related acute lung injury (ALI). This study investigated key molecular mechanisms involved in the hyperactivation of PMNs during ALI. A mouse model of sepsis-related ALI was generated by lipopolysaccharide (LPS) injection. RNA sequencing identified myosin light chain kinase (MLCK) as the most significant differentially expressed gene (DEG) between PMNs isolated from model and control mice. Myocardin (MYOCD) and serum response factor (SRF) were two of the DEGs that could promote transcription of MLCK by binding to its promoter. Either knockdown of MLCK, MYOCD, or SRF ameliorated dysfunction and edema in the lungs of LPS-treated mice. Kyoto Encyclopedia of Genes and Genomes enrichment analysis suggested that the DEGs are enriched in a ferroptosis-related signaling pathway. The MLCK, MYOCD, or SRF knockdown increased contents of ROS, MDA, ferritin, and ferrous iron, and reduced levels of GSH and GPX4 in the PMNs. However, the MLCK overexpression restored ferroptosis resistance and activity of the PMNs, resulting in increased lung injury. Collectively, this study demonstrates that MYOCD and SRF-mediated MLCK upregulation is correlated with ferroptosis resistance and hyperactivation of PMNs in sepsis-related ALI.

CCL28 modulates neutrophil responses during infection with mucosal pathogens.

The chemokine CCL28 is highly expressed in mucosal tissues, but its role during infection is not well understood. Here, we show that CCL28 promotes neutrophil accumulation in the gut of mice infected with Salmonella and in the lung of mice infected with Acinetobacter. Neutrophils isolated from the infected mucosa expressed the CCL28 receptors CCR3 and, to a lesser extent, CCR10, on their surface. The functional consequences of CCL28 deficiency varied between the two infections: Ccl28-/- mice were highly susceptible to Salmonella gut infection but highly resistant to otherwise lethal Acinetobacter lung infection. In vitro, unstimulated neutrophils harbored pre-formed intracellular CCR3 that was rapidly mobilized to the cell surface following phagocytosis or inflammatory stimuli. Moreover, CCL28 stimulation enhanced neutrophil antimicrobial activity, production of reactive oxygen species, and formation of extracellular traps, all processes largely dependent on CCR3. Consistent with the different outcomes in the two infection models, neutrophil stimulation with CCL28 boosted the killing of Salmonella but not Acinetobacter. CCL28 thus plays a critical role in the immune response to mucosal pathogens by increasing neutrophil accumulation and activation, which can enhance pathogen clearance but also exacerbate disease depending on the mucosal site and the infectious agent.

Identification and validation of anti-protein arginine methyltransferase 5 (PRMT5) antibody as a novel biomarker for systemic sclerosis (SSc)

ObjectivesIn the complex panorama of autoimmune diseases, the characterisation of pivotal contributing autoantibodies that are involved in disease progression remains challenging. This study aimed to employ a global antibody profiling...

Iron-laden macrophage-mediated paracrine profibrotic signaling induces lung fibroblast activation.

Idiopathic pulmonary fibrosis (IPF) is a devastating condition characterized by progressive lung scarring and uncontrolled fibroblast proliferation, inevitably leading to organ dysfunction and mortality. Although elevated iron levels have been observed in patients and animal models of lung fibrosis, the mechanisms linking iron dysregulation to lung fibrosis pathogenesis, particularly the role of macrophages in orchestrating this process, remain poorly elucidated. Here we evaluate iron metabolism in macrophages during pulmonary fibrosis using both in vivo and in vitro approaches. In murine bleomycin- and amiodarone-induced pulmonary fibrosis models, we observed significant iron deposition and lipid peroxidation in pulmonary macrophages. Intriguingly, the ferroptosis regulator glutathione peroxidase 4 (GPX4) was upregulated in pulmonary macrophages following bleomycin instillation, a finding corroborated by single-cell RNA sequencing analysis. Moreover, macrophages isolated from fibrotic mouse lungs exhibited increased transforming growth factor (TGF)-β1 expression that correlated with lipid peroxidation. In vitro, iron overload in bone marrow-derived macrophages triggered lipid peroxidation and TGF-β1 upregulation, which was effectively suppressed by ferroptosis inhibitors. When cocultured with iron-overloaded macrophages, lung fibroblasts exhibited heightened activation, evidenced by increased α-smooth muscle actin and fibronectin expression. Importantly, this profibrotic effect was attenuated by treating macrophages with a ferroptosis inhibitor or blocking TGF-β receptor signaling in fibroblasts. Collectively, our study elucidates a novel mechanistic paradigm in which the accumulation of iron within macrophages initiates lipid peroxidation, thereby amplifying TGF-β1 production, subsequently instigating fibroblast activation through paracrine signaling. Thus, inhibiting iron overload and lipid peroxidation warrants further exploration as a strategy to suppress fibrotic stimulation by disease-associated macrophages. NEW & NOTEWORTHY This study investigates the role of iron in pulmonary fibrosis, specifically focusing on macrophage-mediated mechanisms. Iron accumulation in fibrotic lung macrophages triggers lipid peroxidation and an upregulation of transforming growth factor (TGF)-β1 expression. Coculturing iron-laden macrophages activates lung fibroblasts in a TGF-β1-dependent manner, which can be mitigated by ferroptosis inhibitors. These findings underscore the potential of targeting iron overload and lipid peroxidation as a promising strategy to alleviate fibrotic stimulation provoked by disease-associated macrophages.

Acid-degradable lipid nanoparticles enhance the delivery of mRNA.

Lipid nanoparticle (LNP)-mRNA complexes are transforming medicine. However, the medical applications of LNPs are limited by their low endosomal disruption rates, high toxicity and long tissue persistence times. LNPs that rapidly hydrolyse in endosomes (RD-LNPs) could solve the problems limiting LNP-based therapeutics and dramatically expand their applications but have been challenging to synthesize. Here we present an acid-degradable linker termed 'azido-acetal' that hydrolyses in endosomes within minutes and enables the production of RD-LNPs. Acid-degradable lipids composed of polyethylene glycol lipids, anionic lipids and cationic lipids were synthesized with the azido-acetal linker and used to generate RD-LNPs, which significantly improved the performance of LNP-mRNA complexes in vitro and in vivo. Collectively, RD-LNPs delivered mRNA more efficiently to the liver, lung, spleen and brains of mice and to haematopoietic stem and progenitor cells in vitro than conventional LNPs. These experiments demonstrate that engineering LNP hydrolysis rates in vivo has great potential for expanding the medical applications of LNPs.