Lung Cell Apoptosis Research Articles

Evidence for Cytotoxicity and Mitochondrial Dysfunction in Human Lung Cells Exposed to Biomass Burning Aerosol Constituents: Levoglucosan and 4-Nitrocatechol

Biomass burning (BB) emissions are one of the largest sources of carbonaceous aerosol, posing a significant risk as an airway irritant. Important BB markers include wood pyrolysis emissions, such as levoglucosan (LG) that is an anhydrous sugar bearing a six-carbon ring structure (i.e., 1,6-anhydro-β-D-glucopyranose). Atmospheric chemical aging of BB-derived aerosol (BBA) in the presence of nitrogen oxides (NOx) can yield nitro-aromatic compounds, including 4-nitrocatechol (4NC). There is building evidence that NOx-mediated chemical aging of BBA poses a more serious exposure effect than primary pyrolysis emissions. This study provides a comparative toxicological assessment following the exposure to important BBA marker compounds in human lung cells (i.e., A549 and BEAS-2B) to determine whether aromatic 4NC is more toxic than BBA-bound anhydrous carbohydrate (i.e., LG). We determined inhibitory concentration-50 (IC50) and examined reactive oxygen species (ROS) changes, mitochondrial dysfunction, and apoptosis induction in the two cell lines following exposure to LG and 4NC in a dose-response manner. In the BEAS-2B cells, estimated IC50 values for 4NC were 33 and 8.8 μg mL-1, and for LG were 2546 and ∼ 3 × 107 μg mL-1 at 24 h and 48 h of exposure, respectively. A549 cells exhibited a much higher IC50 value than BEAS-2B cells. LG exposures resulted in mitochondrial stress with viability inhibition, but cells recovered with increasing exposure time. 4NC exposures at 200 μg mL-1 resulted in the induction of apoptosis at 6 h. Mitochondrial dysfunction and ROS imbalance induced the intrinsic apoptotic pathway induction following 4NC exposures. While increased ROS is caused by LG exposure in lung cells, 4NC is a marker of concern during BB emissions, as we observed apoptosis and high mitochondrial ROS in both lung cells at atmospherically-relevant aerosol concentrations. It may be associated with higher airway or inhalation pathologies in higher BBA emissions, such as wildfires or during wood combustion.

Sirt4 Overexpression Modulates the JAK2/STAT3 and PI3K/AKT/mTOR Axes to Alleviate Sepsis-Induced Acute Lung Injury.

Sepsis-induced acute lung injury (ALI) is a severe organ dysfunction characterized by lung inflammation and apoptosis. The mechanisms underlying sepsis-induced ALI remain poorly understood. Here, we determined the effects of sirtuin 4 (SIRT4) on sepsis-induced ALI. Lipopolysaccharide (LPS)-induced injury cell and cecal ligation and puncture (CLP) animal models were established. Overexpression vectors and lentiviral transfections were used to upregulate SIRT4 expression. Lung cell apoptosis, inflammation, and the levels of associated factors were evaluated. Changes in the PI3K/AKT/mTOR and JAK2/STAT3 pathways were measured, and their potential involvement was examined using LY294002 (PI3K inhibitor), 740 Y-P (PI3K agonist), AG490 (JAK2 inhibitor), and coumermycin A1 (JAK2 agonist). Lower SIRT4 expression was observed in LPS-exposed A549 cells and CLP rats. In LPS-induced A549 cells, Sirt4 overexpression enhanced cell viability, resisted apoptosis, restored the expression of apoptosis-associated proteins (HMB1, cleaved CASP3, BAX, and BCL), and reduced the secretion of pro-inflammatory cytokines (IL-6, IL-1β, and TNF-α). In CLP rats, Sirt4 overexpression prolonged survival time, alleviated lung histopathological damage, reduced pulmonary edema, mitigated lung infection, decreased lung apoptosis, and lowered serum levels of inflammatory cytokines. Furthermore, Sirt4 overexpression blocked JAK2/STAT3/AKT/mTOR phosphorylation. 740 Y-P and coumermycin A1 reversed the protective effects of Sirt4 overexpression in LPS-treated A549 cells, resulting in decreased cell viability and increased apoptosis. LY294002 and AG490 enhanced the protective effects of Sirt4 overexpression in LPS-treated A549 cells. SIRT4 alleviates sepsis-induced ALI by inhibiting JAK2/STAT3/PI3K/AKT/mTOR signaling. Upregulating SIRT4 expression may serve as an innovative therapeutic approach for lung injury management in sepsis.

DNA-PKcs modulates mouse lung homeostasis via the regulation of mitochondrial fission

BackgroundThe role of DNA-dependent protein kinase catalytic subunit (DNA-PKcs) is multifaceted, paradoxically promoting both cell survival and cell death across multiple organs. However, its impact on lung homeostasis remains elusive. Here, we investigate the function of DNA-PKcs in mouse lungs, aiming to elucidate its role for lung abnormalities associated with DNA-PKcs deficiency. Materials and methodsHistological assessment and immunohistochemistry were used to reveal the pathological changes of the lungs in DNA-PKcs-deficient mice. Transcriptomic analysis identified differentially expressed genes and pathways in DNA-PKcs-deficient lungs. Furthermore, mitochondrial dysfunction induced by DNA-PKcs deficiency was investigated by qPCR and immunoblotting. Mouse primary lung fibroblasts were used to evaluate the potential therapeutic effect of inhibiting mitochondrial fission with Mdivi-1. Key findingsIn DNA-PKcs-deficient mouse lungs, we observed pathological changes including alveolar septal thickening, capillary congestion and hemorrhage, along with lung cell proliferation. Transcriptome analysis revealed an upregulation of the reactive oxygen species (ROS) biosynthesis process and the apoptotic signaling pathway caused by DNA-PKcs deficiency. Further investigations demonstrated that DNA-PKcs deficiency led to mitochondrial dysfunction and increased oxidative stress, along with increased cell apoptosis in the mouse lungs. Notably, we detected enhanced phosphorylation of the mitochondrial fission protein DRP1 in DNA-PKcs-deficient mouse lungs. Intriguingly, inhibiting mitochondrial fission using Mdivi-1 suppressed cell death in primary mouse lung fibroblasts with siRNA-mediated DNA-PKcs knockdown. SignificanceOur study provides insights into the crucial role of DNA-PKcs in sustaining lung homeostasis via the maintenance of mitochondrial functionality and provides a therapeutic strategy targeting mitochondrial fission against DNA-PKcs deficiency-associated lung diseases.

Network pharmacology and phytochemical composition combined with validation in vivo and in vitro reveal the mechanism of platycodonis radix ameliorating PM2.5-induced acute lung injury

Ethnopharmacological relevancePlatycodonis radix (PR), the root of Platycodon grandiflorus (Jacq.) A. DC., is a traditional Chinese medicine recognized for its dual role as both a medicinal and dietary substance, exhibiting significant anti-inflammatory properties. It is frequently utilized in the treatment of lung diseases. However, the molecular mechanisms by which PR exerts its effects in the treatment of acute lung injury (ALI) remain unclear. Aim of the studyThis study presents a novel strategy that integrates network pharmacology, molecular docking, untargeted metabolomics analysis and experimental validation to investigate the molecular mechanisms through which PR treats ALI. Materials and methodInitially, the bioactive components of PR, along with its targets and pathways in the treatment of ALI, were identified using network pharmacology. Following this, preliminary validation was conducted through molecular docking. The active ingredients in the aqueous extract of PR were characterized using HPLC-MS. Finally, in vivo and in vitro experiments were performed to further validate the findings from the network pharmacology. ResultsA total of 14 bioactive components and 156 effective targets were identified using the TCMSP, DisGeNET, Genecard, OMIM databases and Venny 2.1.0. Protein-protein interaction (PPI) analysis revealed 22 core targets including TP53, AKT1, STAT3 and JUN. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses indicated that these targets primarily participate in the regulation of cellular apoptosis, lung cancer and inflammatory pathways. Molecular docking demonstrated that four bioactive components exhibited strong affinities with their respective docking targets. LC-MS analysis confirmed that the aqueous extract of PR contained 87 components, including two active ingredients identified through network pharmacology and molecular docking. Preliminary validation was conducted in mice with ALI induced by acute PM2.5 exposure, revealing that the aqueous extract of PR reduced inflammatory factor levels in bronchoalveolar lavage fluid, enhanced antioxidant capacity in lung tissue, and decreased lung cell apoptosis in PM2.5-exposed mice. Notably, PR alleviated PM2.5-induced ALI through the STAT3, JUN, and AKT1 signaling pathways. Similarly, the results of in vitro intervention experiments further confirmed that the aqueous extract of PR protected pulmonary epithelial cells against PM2.5 exposure through activating AKT1 sinalling pathway, and inhibiting STAT3 and JUN signalling pathways. ConclusionThis study identifies the active components of PR and elucidates the molecular mechanisms by which PR alleviates ALI, specifically by inhibiting the phosphorylation levels of STAT3 and c-JUN, or by activating the phosphorylation level of AKT1. These results provide a foundational basis for the application of PR in the treatment or prevention of lung injuries induced by particulate matter.

Aucubin Alleviates Chronic Obstructive Pulmonary Disease by Activating Nrf2/HO-1 Signaling Pathway.

Chronic obstructive pulmonary disease (COPD) is a common chronic respiratory disease with high death rates. Aucubin is an iridoid glycoside extracted from Eucommia ulmoides with antioxidative and anti-inflammatory properties in human diseases. This study aimed to investigate its specific function in mouse and cell models of COPD. The COPD mouse model was established by exposing mice to a long-term cigarette smoke (CS). The number of inflammatory cells and the contents of inflammatory factors tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6), and IL-8 in bronchoalveolar lavage fluid (BALF) of CS-exposed mice were measured. The levels of superoxide dismutase (SOD), glutathione (GSH), malondialdehyde (MDA), and myeloperoxidase (MPO) in the lung tissues were estimated. Masson staining and hematoxylin-eosin (H&E) staining were utilized to evaluate pulmonary fibrosis and emphysema in CS-treated mice. Cell apoptosis in the lung tissues was estimated by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) assay. Western blot was applied to quantify protein levels of nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), and apoptotic markers. COPD cell model was established by exposing mouse lung epithelial cells (MLE12) with cigarette smoke extract to further verify the properties of aucubin in vitro. Aucubin reduced the number of inflammatory cells and decreased the contents of TNF-α, IL-6, and IL-8 in BALF of CS-treated mice. The oxidative stress, lung emphysema, fibrosis, and lung cell apoptosis induced by CS exposure were ameliorated by aucubin administration. Aucubin activated the Nrf2/HO-1 signaling pathway in vitro and in vivo. Pretreatment with ML385, a specific Nrf2 inhibitor, antagonized the protective effects of aucubin on inflammation, oxidative stress, fibrosis, and cell apoptosis in COPD. Aucubin alleviates inflammation, oxidative stress, apoptosis, and pulmonary fibrosis in COPD mice and CSE-treated MLE12 cells by activating the Nrf2/HO-1 signaling pathway.

Gypenoside XLIX Activates the Sirt1/Nrf2 Signaling Pathway to Inhibit NLRP3 Inflammasome Activation to Alleviate Septic Acute Lung Injury.

Currently, treatment options for acute lung injury (ALI) are limited. Gypenoside XLIX (Gyp-XLIX) is known for its anti-inflammatory properties, but there is a lack of extensive research on its effects against ALI. This study induced ALI in mice through cecal ligation and puncture surgery and investigated the biological activity and potential mechanisms of Gypenoside XLIX (40mg/kg) by intraperitoneal injection. The in vitro ALI model was established using mouse lung epithelial (MLE-12) cells stimulated with lipopolysaccharide (LPS) and adenosine triphosphate (ATP). Various methods, including Hematoxylin and Eosin (H&E) staining, biochemical assay kits, Quantitative Polymerase Chain Reaction (qPCR) analysis, Western blotting, Terminal deoxynucleotidyl transferase dUTP Nick End Labeling (TUNEL) assay, immunofluorescence, and flow cytometry, were employed for this research. The results indicated that pretreatment with Gypenoside XLIX significantly alleviated pathological damage in mouse lung tissues and reduced the expression levels of inflammatory factors. Additionally, Gypenoside XLIX inhibited ROS levels and NLRP3 inflammasome, possibly mediated by the Sirt1/Nrf2 signaling pathway. Moreover, Gypenoside XLIX significantly inhibited sepsis-induced lung cell apoptosis and excessive autophagy of mitochondria. Specifically, it suppressed mitochondrial pathway apoptosis and the Pink1/Parkin pathway of mitochondrial autophagy. These findings reveal the multifaceted effects of Gypenoside XLIX in anti-inflammatory, antioxidative, and inhibition of cell apoptosis and autophagy. This provides strong support for its therapeutic potential in sepsis-related lung injuries.

Esaxerenone Inhibits Interferon-γ Induced Pyroptosis of Macrophages in the Lungs of Aldosterone-treated Mice.

Lung immune cells such as lymphocytes and macrophages can induce an inflammatory response due to the activation of mineralocorticoid receptor (MR), which is manifested by the infiltration of inflammatory cells and the secretion of inflammatory cytokines and subsequent apoptosis, pyroptosis and necrosis of intrinsic lung cells and immune cells. Macrophages are immune cells that are abundant in the lung and act as the first line of defense against pathogens but are also aggravating factors of infection. The activation of the renin-angiotensin-aldosterone system (RAAS), especially aldosterone-stimulated MR activation, can induce macrophage and CD8+T cell aggregation and the secretion of cytokines such as tumor necrosis factor-α (TNF-α) and interferon-gamma (IFN-γ). Increased IFN-γ secretion can induce macrophage pyroptosis and the release of interleukin 1-β (IL-1β), aggravating lung injury. In this study, lung injury in C57BL/6 mice was induced by subcutaneous micro-osmotic pump infusion of aldosterone. After 12weeks of administration, the kidney, heart, blood vessels and lungs all showed obvious inflammatory injury, which manifested as rapid accumulation of macrophages. The overexpression of IFN-γ in the lungs of aldosterone-treated mice and the stimulation of MH-S and RAW264.7 alveolar macrophages (AMs) with aldosterone in vitro showed that IFN-γ induced pyroptosis of macrophages via the activation of the inflammasome, and the MR blocker esaxerenone effectively inhibited this effect and alleviated lung injury. In addition, IFN-γ secreted by CD8+T cells is associated with macrophage pyroptosis. In conclusion, the inhibition of macrophage pyroptosis can effectively alleviate lung injury.

Treadmill training improves lung function and inhibits alveolar cell apoptosis in spinal cord injured rats

Secondary lung injury after SCI is a major cause of patient mortality, with apoptosis playing a key role. This study aimed to explore the impact of treadmill training and miR145-5p on the MAPK/Erk signaling pathway and apoptosis in rats with complete SCI. SD rats were used to establish T10 segmental complete SCI models and underwent treadmill training 3, 7, or 14 days postinjury. Various techniques including arterial blood gas analysis, lung wet/dry weight ratio, HE staining, immunofluorescence staining, immunohistochemical staining, qRT-PCR, and Western blotting were employed to assess alterations in lung function and the expression levels of crucial apoptosis-related factors. In order to elucidate the specific mechanism, the impact of miR145-5p on the MAPK/Erk pathway and its role in apoptosis in lung cells were confirmed through miR145-5p overexpression and knockdown experiments. Following spinal cord injury (SCI), an increase in apoptosis, activation of the MAPK/Erk pathway, and impairment of lung function were observed in SCI rats. Conversely, treadmill training resulted in a reduction in alveolar cell apoptosis, suppression of the MAPK/Erk pathway, and enhancement of lung function. The gene MAP3K3 was identified as a target of miR145-5p. The influence of miR145-5p on the MAPK/Erk pathway and its impact on apoptosis in alveolar cells were confirmed through the manipulation of miR145-5p expression levels. The upregulation of miR145-5p in spinal cord injury (SCI) rats led to a reduction in MAP3K3 protein expression within lung tissues, thereby inhibiting the MAPK/Erk signaling pathway and decreasing apoptosis. Contrarily, rats with miR145-5p knockdown undergoing treadmill training exhibited an increase in miR145-5p expression levels, resulting in the inhibition of MAP3K3 protein expression in lung tissues, suppression of the MAPK/Erk pathway, and mitigation of lung cell apoptosis. Ultimately, the findings suggest that treadmill training may attenuate apoptosis in lung cells post-spinal cord injury by modulating the MAP3K3 protein through miR145-5p to regulate the MAPK/Erk signaling pathway.

Nano-microflora Interaction Inducing Pulmonary Inflammation by Pyroptosis.

Antimicrobial nanomaterials frequently induce inflammatory reactions within lung tissues and prompt apoptosis in lung cells, yielding a paradox due to the inherent anti-inflammatory character of apoptosis. This paradox accentuates the elusive nature of the signaling cascade underlying nanoparticle (NP)-induced pulmonary inflammation. In this study, we unveil the pivotal role of nano-microflora interactions, serving as the crucial instigator in the signaling axis of NP-induced lung inflammation. Employing pulmonary microflora-deficient mice, we provide compelling evidence that a representative antimicrobial nanomaterial, silver (Ag) NPs, triggers substantial motility impairment, disrupts quorum sensing, and incites DNA leakage from pulmonary microflora. Subsequently, the liberated DNA molecules recruit caspase-1, precipitating the release of proinflammatory cytokines and activating N-terminal gasdermin D (GSDMD) to initiate pyroptosis in macrophages. This pyroptotic cascade culminates in the emergence of severe pulmonary inflammation. Our exploration establishes a comprehensive mechanistic axis that interlinks the antimicrobial activity of Ag NPs, perturbations in pulmonary microflora, bacterial DNA release, macrophage pyroptosis, and consequent lung inflammation, which helps to gain an in-depth understanding of the toxic effects triggered by environmental NPs.

Erythropoietin alleviates lung ischemia-reperfusion injury by activating the FGF23/FGFR4/ERK signaling pathway.

The purpose of the present study was to investigate the effect of erythropoietin (EPO) on lung ischemia-reperfusion injury (LIRI). Sprague Dawley rats and BEAS-2B cells were employed to construct an ischemia-reperfusion (I/R)-induced model in vivo and in vitro, respectively. Afterward, I/R rats and tert-butyl hydroperoxide (TBHP)-induced cells were treated with different concentrations of EPO. Furthermore, 40 patients with LIRI and healthy controls were enrolled in the study. It was observed that lung tissue damage, cell apoptosis and the expression of BAX and caspase-3 were higher in the LIRI model in vivo and in vitro than in the control group, nevertheless, the Bcl-2, FGF23 and FGFR4 expression level was lower than in the control group. EPO administration significantly reduced lung tissue damage and cell apoptosis while also up-regulating the expression of FGF23 and FGFR4. Rescue experiments indicated that EPO exerted a protective role associated with the FGF23/FGFR4/p-ERK1/2 signal pathway. Notably, the expression of serum EPO, FGF23, FGFR4 and Bcl-2 was decreased in patients with LIRI, while the expression of caspase-3 and BAX was higher. EPO could effectively improve LIRI, which might be related to the activation of the FGF23/FGFR4/p-ERK1/2 signaling pathway.

S100A9 exacerbates sepsis-induced acute lung injury via the IL17-NFκB-caspase-3 signaling pathway

BackgroundSepsis-induced acute lung injury (ALI) is associated with considerable morbidity and mortality in critically ill patients. S100A9, a key endothelial injury factor, is markedly upregulated in sepsis-induced ALI; however, its specific mechanism of action has not been fully elucidated. MethodsThe Gene Expression Omnibus database transcriptome data for sepsis-induced ALI were used to screen for key differentially expressed genes (DEGs). Using bioinformatics analysis methods such as Gene Ontology, Kyoto Encyclopedia of Genes and Genomes, and protein-protein interaction network analyses, the pathogenesis of sepsis-induced ALI was revealed. Intratracheal infusion of lipopolysaccharide (LPS, 10 mg/kg) induced ALI in wild-type (WT) and S100A9 knockout mice. Multiomics analyses (transcriptomics and proteomics) were performed to investigate the potential mechanisms by which S100A9 exacerbates acute lung damage. Hematoxylin-eosin, Giemsa, and TUNEL staining were used to evaluate lung injury and cell apoptosis. LPS (10 μg/mL)-induced murine lung epithelial MLE-12 cells were utilized to mimic ALI and were modulated by S100A9 lentiviral transfection. The impact of S100A9 on cell apoptosis and inflammatory responses were identified using flow cytometry and PCR. The expression of interleukin (IL)-17–nuclear factor kappa B (NFκB)–caspase-3 signaling components was identified using western blotting. ResultsSix common DEGs (S100A9, S100A8, IFITM6, SAA3, CD177, and MMP9) were identified in the six datasets related to ALI in sepsis. Compared to WT sepsis mice, S100A9 knockout significantly alleviated LPS-induced ALI in mice, with reduced lung structural damage and inflammatory exudation, decreased exfoliated cell and protein content in the lung lavage fluid, and reduced apoptosis and necrosis of pulmonary epithelial cells. Transcriptomic analysis revealed that knocking out S100A9 significantly affected 123 DEGs, which were enriched in immune responses, defense responses against bacteria or lipopolysaccharides, cytokine-cytokine receptor interactions, and the IL-17 signaling pathway. Proteomic analysis revealed that S100A9 knockout alleviated muscle contraction dysfunction and structural remodeling in sepsis-induced ALI. Multiomics analysis revealed that S100A9 may be closely related to interferon-induced proteins with tetratricopeptide repeats and oligoadenylate synthase-like proteins. LPS decreased MLE12 cell activity, accompanied by high expression of S100A9. The expression of IL-17RA, pNFκB, and cleaved-caspase-3 were increased by S100A9 overexpression and reduced by S100A9 knockdown in LPS-stimulated MLE12 cells. S100A9 knockdown decreases transcription of apoptosis-related markers Bax, Bcl and caspase-3, alleviating LPS-induced apoptosis. ConclusionsS100A9 as a key biomarker of sepsis-induced acute lung injury, and exacerbates lung damage and epithelial cell apoptosis induced by LPS via the IL-17–NFκB–caspase-3 signaling pathway.

Green tea polyphenols inhibit TBBPA-induced lung injury via enhancing antioxidant capacity and modulating the NF-κB pathway in mice.

Tetrabromobisphenol A (TBBPA) is a global pollutant. When TBBPA is absorbed by the body through various routes, it can have a wide range of harmful effects on the body. Green tea polyphenols (GTPs) can act as antioxidants, resisting the toxic effects of TBBPA on animals. The effects and mechanisms of GTP and TBBPA on oxidative stress, inflammation and apoptosis in the mouse lung are unknown. Therefore, we established in vivo and in vitro models of TBBPA exposure and GTP antagonism using C57 mice and A549 cells and examined the expression of factors related to oxidative stress, autophagy, inflammation and apoptosis. The results of the study showed that the increase in reactive oxygen species (ROS) levels after TBBPA exposure decreased the expression of autophagy-related factors Beclin1, LC3-II, ATG3, ATG5, ATG7 and ATG12 and increased the expression of p62; oxidative stress inhibits autophagy levels. The increased expression of the pro-inflammatory factors IL-1β, IL-6 and TNF-α decreased the expression of the anti-inflammatory factor IL-10 and activation of the NF-κB p65/TNF-α pathway. The increased expression of Bax, caspase-3, caspase-7 and caspase-9 and the decreased expression of Bcl-2 activate apoptosis-related pathways. The addition of GTP attenuated oxidative stress levels, restored autophagy inhibition and reduced the inflammation and apoptosis levels. Our results suggest that GTP can attenuate the toxic effects of TBBPA by modulating ROS, reducing oxidative stress levels, increasing autophagy and attenuating inflammation and apoptosis in mouse lung and A549 cells. These results provide fundamental information for exploring the antioxidant mechanism of GTP and further for studying the toxic effects of TBBPA.

Aflatoxin B1 administration causes inflammation and apoptosis in the lungs and spleen

Aflatoxin is a naturally occurring mycotoxin that has numerous toxic effects. The main aim of the present study was to evaluate the toxic effects of aflatoxin B1 (AFB1) on the lungs and spleen. Mice were repeatedly exposed to AFB1 (0.3 mg/kg body weight) on alternate days for four weeks via oral route. The histopathological data in AFB1-treated mice show alveolar epithelial hyperplasia with inflammation and the presence of numerous alveolar macrophages with minimal hemorrhage. There was an increase in vascular neutrophils and interstitial inflammation. The branching of vessels was plugged with neutrophils. AFB1 administration also causes splenomegaly. The AFB1-treated spleen shows the tingible body macrophages (TBM) scattered within the splenic white pulp. Apoptosis may lead to atrophy in a selected region of the white pulp area. There is a decrease in cellularity within the periarteriolar lymphatic sheath (PALS). The inflammation causes the congestion of red pulp with the increase in nuclear debris, and vacuoles are also visible. The flow cytometry data further suggests enhanced apoptosis in lung and spleen cells.

CIAP1/2 can regulate the inflammatory response and lung injury induced by apoptosis in septic rats.

Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS), induced by sepsis, is predominantly caused by inflammation injury. However, there is no clear consensus on how to regulate the inflammatory response. The TNF pathway is one of the primary inflammatory pathways activated in sepsis. cIAP1/2, an essential E3 ubiquitin ligase in the TNF pathway, plays a pivotal role in positively regulating the activation of nuclear factor κB (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways to promote inflammation while inhibiting apoptosis. We found that Birc2 is the only differential expression gene in TNF pathway, and both cIAP1/2 upregulated in lung lysate with worsen lung injury. However, upon inhibiting cIAP1/2 using AZD5582, lung cell apoptosis was reactivated, and a significant improvement in lung injury was observed. Our study shows that cIAP1/2 expression increased in the lung tissue of a CLP rat ALI model. Inhibiting cIAP1/2 with AZD5582, a second mitochondria-derived activator of caspases (SMAC) mimetic, induced increased apoptosis and reduced lung injury. Therefore, inhibiting cIAP1/2 can alleviate sepsis-induced ALI, providing a new target for regulating organ damage induced by sepsis-induced inflammatory responses.

PEDF inhibits LPS-induced acute lung injury in rats and promotes lung epithelial cell survival by upregulating PPAR-γ

BackgroundThe progression of acute lung injury (ALI) involves numerous pathological factors and complex mechanisms, and cause the destruction of epithelial and endothelial barriers. Pigment epithelium-derived factor (PEDF) is an angiogenesis inhibitor and a potential anti-inflammatory factor. The purpose of this study was to investigate the effect of PEDF on lipopolysaccharide (LPS)-induced ALI in rats.MethodsIn vivo, pathological and injury related factors examination were performed on rat lung to investigate the effect of PEDF on ALI. In vitro, the effect of PEDF on inflammatory injury and apoptosis of lung epithelial type II RLE-6TN cell was evaluated, and the expression of inflammatory factors and related pathway proteins and PPAR-γ (in the presence or absence of PPAR-γ inhibitors) were analyzed.ResultsIn vivo results showed that PEDF inhibited the inflammatory factor expression (TNF-α, IL-6 and IL-1β) and progression of ALI and reduced lung cell apoptosis in rats. In vitro results showed that PEDF could effectively inhibit LPS-stimulated inflammatory damage and apoptosis of RLE-6TN cells. PEDF inhibited the RLE-6TN cell injury by enhancing the expression of PPAR-γ.ConclusionsPEDF is an anti-inflammatory factor, which can inhibit apoptosis of lung epithelial cells by upregulating the expression of PPAR-γ and reducing LPS-induced ALI in rats.

Neutrophil extracellular traps induce persistent lung tissue damage via thromboinflammation without altering virus resolution in a mouse coronavirus model

BackgroundDuring infection, neutrophil extracellular traps (NETs) are associated with severity of pulmonary diseases such as acute respiratory disease syndrome. NETs induce subsequent immune responses, are directly cytotoxic to pulmonary cells, and are highly procoagulant. Anticoagulation treatment was shown to reduce in-hospital mortality, indicating thromboinflammatory complications. However, data are sparsely available on the involvement of NETs in secondary events after virus clearance, which can lead to persistent lung damage and postacute sequelae with chronic fatigue and dyspnea. ObjectivesThis study focuses on late-phase events using a murine model of viral lung infection with postacute sequelae after virus resolution. MethodsC57BL/6JRj mice were infected intranasally with the betacoronavirus murine coronavirus (MCoV, strain MHV-A95), and tissue samples were collected after 2, 4, and 10 days. For NET modulation, mice were pretreated with OM-85 or GSK484 and DNase I were administered intraperitoneally between days 2 to 5 and days 4 to 7, respectively. ResultsRapid, platelet-attributed thrombus formation was followed by a second, late phase of thromboinflammation. This phase was characterized by negligible virus titers but pronounced tissue damage, apoptosis, oxidative DNA damage, and presence of NETs. Inhibition of NETs during the acute phase did not impact virus burden but decreased lung cell apoptosis by 67% and oxidative stress by 94%. Prevention of neutrophil activation by immune training before virus infection reduced damage by 75%, NETs by 31%, and pulmonary thrombi by 93%. ConclusionNETs are detrimental inducers of tissue damage during respiratory virus infection but do not contribute to virus clearance.

CSE reduces OTUD4 triggering lung epithelial cell apoptosis via PAI-1 degradation

Ovarian tumor family deubiquitinase 4 (OTUD4), a member of the OTU deubiquitinating enzyme, is implicated to decrease in cancer to regulate cell apoptosis. However, the role of OTUD4 in cigarette smoke induced epithelial cell apoptosis and its mechanism have not been elucidated. In this study, we showed that OTUD4 protein reduced in CSE treated mice and airway epithelial cells. OTUD4 silence aggravated cell apoptosis and emphysematous change in the lung tissue of cigarette smoke extract (CSE) treated mice. Additionally, restoration of OTUD4 in the lung of mice alleviated CSE induced apoptosis and emphysematous morphology change. The effect of OTUD4 on cell apoptosis was also confirmed in vitro. Through protein profile screening, we identified that OTUD4 may interact with plasminogen activator inhibitor 1(PAI-1). We further confirmed that OTUD4 interacted with PAI-1 for de-ubiquitination and inhibiting CSE induced PAI-1 degradation. Furthermore, the protective role of OTUD4 in airway epithelial cells apoptosis was blocked by PAI-1 deactivation. Taken together, our data suggest that OTUD4 regulates cigarette smoke (CS)-triggered airway epithelial cell apoptosis via modulating PAI-1 degradation. Targeting OUTD4/PAI-1 signaling might potentially provide a therapeutic target against the lung cell apoptosis in cigarette smoke (CS)-induced emphysema.

Inhibitors Targeting the F-BOX Proteins.

F-box proteins are involved in multiple cellular processes through ubiquitylation and consequent degradation of targeted substrates. Any significant mutation in F-box protein-mediated proteolysis can cause human malformations. The various cellular processes F-box proteins involved include cell proliferation, apoptosis, invasion, angiogenesis, and metastasis. To target F-box proteins and their associated signaling pathways for cancer treatment, researchers have developed thousands of F-box inhibitors. The most advanced inhibitor of FBW7, NVD-BK M120, is a powerful P13 kinase inhibitor that has been proven to bring about apoptosis in cancerous human lung cells by disrupting levels of the protein known as MCL1. Moreover, F-box Inhibitors have demonstrated their efficacy for treating certain cancers through targeting particular mutated proteins. This paper explores the key studies on how F-box proteins act and their contribution to malignancy development, which fabricates an in-depth perception of inhibitors targeting the F-box proteins and their signaling pathways that eventually isolate the most promising approach to anti-cancer treatments.

Research progress of extracellular vesicles and exosomes derived from mesenchymal stem cells in the treatment of oxidative stress-related diseases.

There is growing evidence that mesenchymal stem cell-derived extracellular vesicles and exosomes can significantly improve the curative effect of oxidative stress-related diseases. Mesenchymal stem cell extracellular vesicles and exosomes (MSC-EVs and MSC-Exos) are rich in bioactive molecules and have many biological regulatory functions. In this review, we describe how MSC-EVs and MSC-Exos reduce the related markers of oxidative stress and inflammation in various systemic diseases, and the molecular mechanism of MSC-EVs and MSC-Exos in treating apoptosis and vascular injury induced by oxidative stress. The results of a large number of experimental studies have shown that both local and systemic administration can effectively inhibit the oxidative stress response in diseases and promote the survival and regeneration of damaged parenchymal cells. The mRNA and miRNAs in MSC-EVs and MSC-Exos are the most important bioactive molecules in disease treatment, which can inhibit the apoptosis, necrosis and oxidative stress of lung, heart, kidney, liver, bone, skin and other cells, and promote their survive and regenerate.

LncRNA H19 aggravates primary graft dysfunction after lung transplantation via KLF5-mediated activation of CCL28

The present study aims to elucidate the possible involvement of H19 in primary graft dysfunction (PGD) following lung transplantation (LT) and the underlying mechanism. The transcriptome data were obtained through high-throughput sequencing analysis, and the differential long noncoding RNAs and messenger RNAs were screened for coexpression analysis. The interaction among H19, KLF5 and CCL28 was analyzed. A hypoxia-induced human pulmonary microvascular endothelial cell injury model was established, in which H19 was knocked down to elucidate its effect on the lung function, inflammatory response, and cell apoptosis. An orthotopic left LT model was constructed for in vivo mechanistic validation. High-throughput transcriptome sequencing analysis revealed the involvement of the H19/KLF5/CCL28 signaling axis in PGD. Silencing of H19 reduced inflammatory response and thus improved PGD. CCL28 secreted by human pulmonary microvascular endothelial cells after LT recruited neutrophils and macrophages. Mechanistic investigations indicated that H19 augmented the expression of CCL28 by binding to the transcription factor KLF5. Abundant expression of CCL28 reversed the alleviating effect of H19 silencing on PGD. In conclusion, the results point out that H19 exerts a promoting effect on PGD through increasing KLF5 expression and the subsequent CCL28 expression. Our study provides a novel insight into the mechanism of action of H19.