HDAC3 deficiency protects against acute lung injury by maintaining epithelial barrier integrity through preserving mitochondrial quality control

OTUD1 inhibits macrophage ferroptosis via regulation of AMPK and GSK3β/β-catenin signaling pathways exerting protective effects in sepsis-induced acute lung injury

Sepsis is a life-threatening organ dysfunction caused by dysregulated inflammatory and immune responses to infection. Its global incidence and mortality remain high, posing a severe threat to public health. Acute lung injury (ALI) is a common and serious complication of sepsis. Current understanding of the pathogenesis and effective therapeutic strategies for sepsis-induced acute lung injury (SI-ALI) remains insufficient. This study aims to investigate the role and underlying mechanisms of the deubiquitinase OTUD1 in sepsis-induced pulmonary injury. Using a mouse model of sepsis-induced lung injury combined with genetic knockout techniques and ferroptosis inhibitors, we systematically analyzed the protective effects of OTUD1 in sepsis-related lung damage and explored the regulatory roles of AMPK and GSK3β/β-catenin signaling pathways. Results demonstrated that OTUD1 gene deletion exacerbated lung tissue damage and inflammatory responses in septic mice while increasing ferroptosis levels; pretreatment with the ferroptosis inhibitor Ferrostatin-1 significantly ameliorated these effects. Further mechanistic studies revealed that OTUD1 may regulate ferroptosis levels in lung tissue by modulating the activation status of AMPK and GSK3β/β-catenin pathways. Specifically, OTUD1 may remove K63-linked ubiquitin chains from AMPK, altering its protein conformation and subsequently promoting AMPK phosphorylation to regulate the GSK3β/β-catenin signaling cascade. Collectively, this study provides the first systematic elucidation of OTUD1's protective role in sepsis-induced lung injury and its relationship with ferroptosis, offering novel molecular targets and theoretical foundations for the treatment of sepsis-associated pulmonary damage.

LCMR1 deficiency exacerbates LPS‑induced lung injury in lung‑on‑a‑chip and mouse models

The oncogene lung cancer metastasis‑related protein 1 (LCMR1) is associated with neoplastic diseases and LCMR1 conditional knockout affects cell homeostasis. In the present study, the role of LCMR1 in lipopolysaccharide (LPS)‑induced acute lung injury (ALI) was investigated. Firstly, wild‑type C57BL/6 mice were used to establish an LPS‑induced ALI model via intratracheal injection of LPS, and the expression of LCMR1 was examined at 24, 48, 72 and 96 h after injury. The LPS‑induced lung injury model was subsequently constructed in mice with conditional knockout of LCMR1 in type II alveolar epithelial cells (AEC‑II). Subsequently, histopathological analysis, lung wet/dry weight ratio comparisons and lung function tests were performed; survival rates after LPS challenge of the conditional knockout mice were measured; bronchoalveolar lavage fluid (BALF) was collected, and the concentrations of protein and inflammatory cytokines in BALF were measured; and transmission electron microscopy of lung tissue was conducted to evaluate the degree of lung injury. To further investigate the mechanism, a lung‑on‑a‑chip model with overexpression or knockdown of LCMR1 was constructed to simulate the alveolar environment under LPS treatment. The expression levels of E‑cadherin and pro‑pulmonary surfactant C precursor (proSP‑C) in the chips were determined by immunofluorescence, and the integrity of the air‑blood barrier was analyzed using a permeability assay. In the mouse model, LCMR1 expression was downregulated in wild‑type mice with LPS‑induced lung injury. LCMR1 conditional knockout in AEC‑II caused increased mortality, impaired lung function, aggravated pathological damage and increased the inflammatory response in mice with LPS‑induced ALI. Furthermore, in the lung‑on‑a‑chip model, LCMR1 knockdown reduced the expression of E‑cadherin and proSP‑C, and impaired the air‑blood barrier function, whereas LCMR1 overexpression attenuated these effects, which may be related to cell differentiation dysfunction and enhanced apoptosis. In conclusion, the present study revealed that LCMR1 deficiency may exacerbate LPS‑induced ALI and could be considered a novel target for intervention in ALI.

Cornus officinalis loganin attenuates acute lung injury in mice via regulating the PI3K/AKT/NLRP3 axis

ETHNOPHARMACOLOGICAL RELEVANCE

Cornus officinalis (CO), a pharmaceutical and food product, can reduce inflammation, alleviate oxidative stress and lower blood sugar levels. In particular, CO has been used to treat severe COVID-19 patients during the pandemic, revealing its protective effects against pneumonia.

AIM

In this study, the mitigating effects of CO ethanol extract (COEE) on acute lung injury (ALI) and the molecular mechanism were investigated and the main active components of COEE were screened.

METHODS

The anti-inflammatory effects of CO on model animals assessed by evaluating the levels of proinflammatory factors and inflammasome components by HE staining technique, ELISA, RT-qPCR and immunofluorescence assays. Moreover, CCK8, LDH, and RT‒qPCR assays were also performed to assess the effect of CO on cell viability and its anti-inflammatory efficacy in vitro. The mRNA expression of inflammatory factors (IL-1β and TNF-α), and the protein expression of NLRP3 inflammasome members was evaluated. In addition, the molecular mechanisms and core pharmacodynamic components of CO were inferred by network pharmacology, and the relevant pathway targets were analysed and verified by immunohistochemistry, Western blotting and RT‒qPCR. In vivo and in vitro models were also established to verify the effects of the main active ingredient Loganin (LOG) on ALI and the related molecular mechanisms.

RESULTS

COEE significantly suppressed inflammation, mitigated lung tissue damage, and inhibited NLRP3 inflammasome activation in an LPS-induced murine ALI model and an inflammatory cell model. Network pharmacology screening and experimental data revealed that the PI3K/AKT signalling pathway is the direct target of CO, as COEE administration potently inhibited the activation of the PI3K/AKT/NLRP3 signalling pathway in vitro and in vivo, whereas the PI3K/AKT pathway agonist YS-49 apparently impaired the effects of COEE. Further studies revealed that LOG, a core ingredient in CO, mediated the effects of COEE via direct targeting of AKT1, and different doses of LOG had consistent and strong protective effects on ALI model mice.

CONCLUSION

COEE exerts therapeutic effects on LPS-induced ALI model mice by inhibiting the activation of the PI3K/AKT pathway and preventing the overactivation of the NLRP3 inflammasome, and LOG is the core medicinal substance. These findings also provide supporting evidence for the development of new nutraceuticals for the prevention and treatment of ALI.

Identification and validation of PARK7 as a novel mitochondria-related signature associated with immune microenvironment in asthma

BACKGROUND

Asthma is one of the most common respiratory diseases characterized by immune cell infiltration. However, the roles of mitochondria-related genes and their crosstalk with immune cell infiltration in asthma remain unclear. This study aimed to investigate the role and interaction of mitochondria-related genes and the immune cells in asthma through both bioinformatic analysis and experimental approaches.

METHODS

The microarray data GSE76262 was obtained from NCBI GEO datasets, and differentially expressed genes (DEGs) were acquired by GEO2R. DAVID database was used for Gene Ontology, and Kyoto Encyclopedia of Genes and Genomes enrichment analyses. Mitochondrial genes were downloaded from Human MitoCarta3.0, and then Mitochondria-related DEGs (MitoDEGs) were obtained. STRING database was used to construct the Protein-Protein Interaction network, and then the hub genes were identified. The receiver operating characteristic curves were used to assess the diagnostic effects of hub genes in asthma patients. The infiltration of immune cells was analyzed by using the ImmuCellAI database. The expression of hub MitoDEGs was validated in an HDM-induced animal model. The compound-23 was utilized to investigate the function of PARK7 both in vivo and in vitro.

RESULTS

Mitochondria were predicted to be involved in the pathology and physiology of asthma. The 47 MitoDEGs were identified, and three hub MitoDEGs (DNM1L, FIS1, and PARK7) were predicted to participate in asthma pathogenesis. Compared to DNM1L and FIS1, PARK7 had the most diagnostic effectiveness. The hub MitoDEGs were mainly positively associated with macrophages, monocytes, and CD8+T cells, while negatively associated with multiple CD4+T cells. Compared to the control group, the mRNA and protein expression levels of DNM1L, FIS1, and PARK7 were downregulated in the model group. Additionally, activating the function of PARK7 via compound-23 alleviated the mitochondrial damage, decreased the production of IL-25, IL-33, CCL17 and CCL20, subsequently improved the immune microenvironment and airway inflammation.

CONCLUSION

These results suggested that mitochondria-related genes were involved in the pathological processes of asthma, and verified the protective role of PARK7 in HDM-induced asthma models, which provided the potential insight into the clinical diagnosis and therapy of asthma.

Ophiopogonin D Alleviates Sepsis-Induced Acute Lung Injury Through Improving Microvascular Endothelial Barrier Dysfunction via Inhibition of HIF-1α-VEGF Pathway

Pulmonary endothelial barrier dysfunction is a hallmark of sepsis-induced acute lung injury (ALI). Ophiopogonin D (OP-D), isolated from the roots of Ophiopogon japonicus, is involved in regulating inflammation, apoptosis and intestinal permeability. However, the role of OP-D in ALI has not been reported and the related mechanisms remain unclear. In this study, cecal ligation and puncture (CLP) was used to establish a septic ALI model in mice. We found that OP-D effectively alleviated lung pathological damage. Moreover, OP-D decreased pulmonary microvascular permeability, restrained the inflammatory response and apoptosis in murine lung tissues and LPS-exposed PMVECs. Specifically, OP-D exerted the beneficial effects via mediating the inactivation of HIF-1α-VEGF pathway, which was partly abrogated by the overexpression of HIF-1α. Collectively, our findings showed that OP-D protected against sepsis-induced ALI through improving pulmonary microvascular endothelial barrier dysfunction via suppressing HIF-1α-VEGF pathway.

Compound C1 reduced inflammation and activated autophagy in alveolar macrophages in mice

The purpose of this study was to investigate the therapeutic effect of Compound C1 (Comp-C1) on lipopolysaccharide (LPS) -mediated sepsis acute lung injury (SALI) in vitro alveolar macrophage model and its regulatory mechanism. In vitro cultured mouse alveolar macrophages (MH-S) were treated with LPS. The expression and localization of transcription factor EB (TFEB) after LPS stimulation were detected. Then the cells were treated with LPS (1 μg/mL) and Comp-C1 (1 μM) for 24 h. RT-qPCR and Western Blot were used to detect the mRNA expression of inflammatory factors. Western blot was used to detect the expression of TFEB, lysosome-associated membrane protein 1 (LAMP1), P62 and microtubule-associated protein 1 light chain 3B (LC3B). TFEB-EGFP-Hela and mCherry-EGFP-LC3-Hela cells were used to detect the changes of TFEB nuclear expression and intracellular autophagic flux after Comp-C1 administration by immunofluorescence. The results showed that the expression of inflammatory factors was the highest after 1 μg / mL LPS stimulation for 24 hours. At the same time, the expression of TFEB gene and protein decreased after LPS stimulation, and the content of TFEB in cytoplasm and nucleus decreased by separating cytoplasmic and nuclear proteins. The content of LAMP1 decreased, and the expression of autophagy-related proteins reflected the inhibition of autophagy. After treatment with Comp-C1, the inflammatory factors were significantly decreased, the expression of TFEB and LAMP1 was significantly increased, and the expression of autophagy genes in the cells was restored. The up-regulation of TFEB nuclear expression after Comp-C1 administration was determined by TFEB-EGFP-Hela cells, and the recovery of autophagy flux and alveolar macrophage function after Comp-C1 administration was determined by mCherry-EGFP-LC3-Hela cells. Therefore, Comp-C1 can alleviate LPS-induced MH-S autophagy dysfunction and reduce inflammatory response by up-regulating TFEB in mouse alveolar macrophages, suggesting that Comp-C1 can be used as a potential drug for the treatment of SALI.

Reprogramming Lung Redox Homeostasis by NIR Driven Ultra-Small Pd Loaded Covalent Organic Framework Inhibits NF-κB Pathway for Acute Lung Injury Immunotherapy

Acute lung injury (ALI) refers to damage to lung related cells, typically caused by an uncontrollable inflammatory response, and over-generated reactive oxygen species (ROS). Increasing evidence suggests that reprogramming lung redox homeostasis holds significant potentials for the clinical treatment of ALI. Herein, the simple synthesis of ultra-small Pd loaded covalent organic framework (COF) (TP@Pd) is reported, which, when combined with near infrared (NIR) irradiation, exhibits nanozyme functionalities, including multiple enzyme mimicking activities and broad spectrum ROS scavenging, thereby promoting tissue repair for ALI immunotherapy. Mechanistically, through the therapeutic strategy of TP@Pd+NIR, the damaged cells and tissues are ameliorated by decreasing intracellular ROS levels (total ROS, ·OH and ·O2 -), downregulating inflammatory cytokines levels (IL-6, TNF-α and IL-1β), upregulating antioxidant factor level (SOD2), inducing macrophage M2 directional polarization (downregulation of iNOS and CD86, and upregulation of IL-10 and CD206), activating immunoregulation (CD4+/CD8+ ratio increase), promoting tissue repair factor levels (upregulation of HSP70 and CD31), and suppressing the NF-κB signaling pathway (downregulation of phosphorylated p65 and IκBα). Furthermore, following intravenous (IV) injection in rats, TP@Pd accumulated in lung tissue for 6 h, indicating the promising therapeutic efficacy via this administration route. Notably, the TP@Pd+NIR strategy demonstrated the excellent synergistic effects in alleviating lung inflammation storms, reducing diffuse alveolar damage, and accelerating lung tissue repair. Summarily, this work has designed a novel TP@Pd+NIR strategy for the synergistic enhancement of ALI amelioration, which may serve as a promising therapeutic approach for other ROS related diseases.

Selenium nanoparticles activate selenoproteins to mitigate septic lung injury through miR-20b-mediated RORγt/STAT3/Th17 axis inhibition and enhanced mitochondrial transfer in BMSCs

Sepsis-induced acute lung injury (ALI) remains a critical clinical challenge with complex inflammatory pathogenesis. While bone marrow mesenchymal stem cells (BMSCs) demonstrate therapeutic potential through anti-inflammatory and cytoprotective effects, their age-related functional decline limits clinical utility. This study developed chitosan-functionalized selenium nanoparticles (SeNPs@CS, 100 nm) to rejuvenate BMSCs through miR-20b-mediated selenoprotein biosynthesis. Mechanistic investigations revealed that SeNPs@CS-treated BMSCs exhibited enhanced mitochondrial transfer capacity, delivering functional mitochondria to damaged alveolar epithelial cells (AECII) for cellular repair. Concurrently, miR-20b upregulation suppressed the RORγt/STAT3/Th17 axis, reducing pro-inflammatory Th17 cell differentiation in CD4+ T lymphocytes. The dual-target mechanism integrates immunomodulation via Th17 pathway inhibition with mitochondrial rejuvenation therapy, representing a paradigm-shifting approach for ALI management. These engineered BMSCs mitigated inflammatory markers in murine models, demonstrating superior efficacy to conventional BMSC therapies. Our findings establish SeNPs@CS-modified BMSCs as a novel therapeutic platform combining nanotechnology-enhanced stem cell engineering with precision immunometabolic regulation, providing new avenues for the treatment of sepsis-induced ALI.

The Role of HDAC3 in Pulmonary Diseases

Histone deacetylases (HDACs), a class of enzymes involved in epigenetic modifications, play a pivotal role in modulating chromatin structure and gene expression. Among these, histone deacetylase 3 (HDAC3) has emerged as a key regulator in diverse cellular pathophysiological processes. The remarkable therapeutic potential of HDAC inhibitors in lung cancer has intensified research into the role of HDAC3 in pulmonary diseases. Through deacetylating histones and non-histone proteins, HDAC3 has been increasingly recognized for its critical involvement in regulating inflammatory responses, fibrotic processes, and oncogenic signaling pathways, positioning it as a compelling therapeutic target. This review systematically examines the structural and functional features of HDAC3 and discusses its multifaceted contributions to pulmonary pathologies, including lung injury, pulmonary fibrosis, and lung cancer. Additionally, we critically evaluate advances in HDAC inhibitor-based therapies for lung cancer, with emphasis on the development of HDAC3-targeted therapies. As a promising therapeutic target for pulmonary diseases, HDAC3 needs to be further investigated to elucidate its regulatory mechanisms and facilitate the development of selective inhibitors for clinical translation.

Advancements in omics technologies: Molecular mechanisms of acute lung injury and acute respiratory distress syndrome (Review)

Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) is an inflammatory response arising from lung and systemic injury with diverse causes and associated with high rates of morbidity and mortality. To date, no fully effective pharmacological therapies have been established and the relevant underlying mechanisms warrant elucidation, which may be facilitated by multi‑omics technology. The present review summarizes the application of multi‑omics technology in identifying novel diagnostic markers and therapeutic strategies of ALI/ARDS as well as its pathogenesis.

The role of TBC1D15 in sepsis-induced acute lung injury: Regulation of mitochondrial homeostasis and mitophagy

Mitochondrial quality control is crucial in sepsis-induced acute lung injury (SI-ALI). Our study investigates how the intracellular protein TBC1D15 regulates mitochondrial quality to improve SI-ALI. We found TBC1D15 levels significantly decreased in the whole blood of sepsis patients, monocytes, lung tissue from SI-ALI mice, and the MLE-12 cellular model (mouse lung epithelial cells). Overexpression of TBC1D15 using adeno-associated viral and lentiviral vectors alleviated lung injury and inflammation in both mouse models and MLE-12 cells, while silencing TBC1D15 exacerbated inflammatory responses. Mechanistically, TBC1D15 overexpression dissociated mitochondria-lysosome contact duration, promoted mitophagy, and restored mitochondrial function. The protective effects of TBC1D15 were reversed by the mitophagy inhibitor Bafilomycin A1. Additionally, TBC1D15 knockdown prolonged mitochondria-lysosome contact time, resulting in worsened mitochondrial dysfunction and increased oxidative stress. Our findings indicate that SI-ALI is characterized by prolonged mitochondria-lysosome contact and impaired mitophagy. Thus, TBC1D15 overexpression presents a promising therapeutic strategy to mitigate mitochondrial dysfunction and reduce lung injury in septic conditions, suggesting potential clinical applications for SI-ALI treatment.

Plant-derived natural compounds for the treatment of acute lung injury: A systematic review of their anti-inflammatory effects in animal models

BACKGROUNDS AND AIMS

Acute lung injury (ALI) is a complex pulmonary disease characterized by a severe inflammatory response. The management of ALI presents a formidable challenge due to the intricate nature of its inflammatory cascade. Numerous studies have highlighted the potential therapeutic benefits of plant-derived natural compounds (PNCs) in treating inflammatory diseases. Our study aims to provide robust current evidence regarding the anti-inflammatory effects and underlying molecular mechanisms of PNCs for ALI treatment.

MATERIALS AND METHODS

The systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, and the protocol was registered in PROSPERO (CRD42024468401). A comprehensive search was conducted in electronic databases including PubMed, Scopus, Web of Science, Embase, China National Knowledge Infrastructure (CNKI), Chinese Scientific Journal database (VIP), Wanfang database, and China biomedical literature service system (SinoMed) up until November 2023. Preclinical studies published in both English and Chinese were included.

RESULTS

Our research encompassed 81 studies, comprising a total of 71 PNCs, including flavonoids, phenylpropanoids, terpenoids, polyphenols, alkaloids, saponins, glycosides, and miscellaneous compounds. This systematic review demonstrated that PNCs played a beneficial role on ALI by regulating the immune response and reducing the release of inflammatory mediators and cytokines. The molecular mechanisms were partially associated with the regulation of Th17/Treg responses, promotion of the polarization of M1-type macrophages to M2-type macrophages, induction of immune cell apoptosis, reversal of microbial dysbiosis in the lungs and the gut, epigenetic modification, and the modulation of inflammatory pathways, including NF-κB, MAPK, TLR4/MyD88, NLRP3/Caspase-1, TGF-β/Smad, Nrf2/HO-1, Rho/ROCK, TLR7/MyD88, and PI3K/AKT, thereby alleviating inflammatory responses and lung damage.

CONCLUSION

The therapeutic effects of PNCs on ALI are mediated through the modulation of immunity and inflammatory pathways. In light of their potential, PNCs represent a promising pharmacological intervention for the treatment of ALI.

Identification and Characterization of Genes Associated with Intestinal Ischemia-Reperfusion Injury and Oxidative Stress: A Bioinformatics and Experimental Approach Integrating High-Throughput Sequencing, Machine Learning, and Validation

Purpose

Intestinal ischemia-reperfusion injury (IIRI) occurs as a result of temporary blood flow interruption, leading to tissue damage upon reperfusion. Oxidative stress plays a critical role in this process, instigating inflammation and cell death. Identifying and characterizing genes associated with the oxidative stress response can offer valuable insights into potential therapeutic targets for managing IIRI.

Patients and Methods

The IIRI dataset was sourced from the NCBI Gene Expression Omnibus Database (GEO), while oxidative stress genes were obtained from the Genecards database. Following the acquisition of differentially expressed genes in IIRI, they were cross-linked with oxidative stress genes to yield IIRI oxidative stress related genes (IOSRGs). The least absolute shrinkage and selection operator, as well as the support vector machine with random forest algorithm, were utilized for machine learning. Subsequently, the PPI network was established, and the Degree and MNC algorithms of the Cytohuba plugin were integrated with the genes obtained through the machine learning algorithms to identify hub IOSRGs (HIOSRGs). A mouse IIRI model and ROC curve were employed to verify the accuracy of HIOSRGs. Finally, siRNA was utilized to suppress the expression of HDAC3 in Caco2 cells, and the changes in oxidative stress levels before and after hypoxia-reoxygenation in Caco2 cells were observed.

Results

A total of 277 OSRGs and 4 HIOSRGs were obtained. Concurrently, in vivo experimental results of IIRI in C57BL/6 mice, and the establishment of ROC curves, reflected the accuracy and specificity of HIOSRGs. The knockdown of HDAC3 in Caco2 cells resulted in increased oxidative stress levels before and after hypoxia-reoxygenation, underscoring the significant role of HDAC3 in IIRI.

Conclusion

This study elucidates the interplay between oxidative stress genes and IIRI, offering novel insights into the potential pathogenesis of IIRI and medical interventions for IIRI.

SARS-CoV-2 N protein induces alveolar epithelial apoptosis via NLRP3 pathway in ARDS

Acute Respiratory Distress Syndrome (ARDS) is a severe inflammatory condition often resulting from sepsis and viral infections, including (Severe Acute Respiratory Syndrome Coronavirus 2) SARS-CoV-2. This study investigates the molecular mechanisms by which the SARS-CoV-2 nucleocapsid (N) protein influences alveolar macrophage activation, leading to alveolar epithelial cell apoptosis and exacerbating ARDS. Single-cell RNA sequencing data from ARDS patients were analyzed to identify cell subpopulations and their interactions, revealing significant macrophage-epithelial cell communication through the (NOD-like receptor family pyrin domain containing 3) NLRP3 pathway. Differential gene expression in SARS-CoV-2-infected macrophages highlighted key genes, with WGCNA pinpointing core modules. In vitro experiments demonstrated that N protein overexpression in MH-S macrophages activates the NLRP3 pathway, promoting M1 macrophage polarization and inducing apoptosis in co-cultured MLE-12 epithelial cells. Immunoprecipitation, pull-down assays, Enzyme-Linked Immunosorbent Assay (ELISA), RT-qPCR, Western blotting, and flow cytometry confirmed these findings. In vivo, ARDS mouse models induced by CLP surgery or N protein administration showed increased M1 macrophage infiltration, heightened inflammatory responses, and significant epithelial cell damage, as evidenced by H&E staining, immunofluorescence, RNA-ISH, and ELISA. These results suggest that the SARS-CoV-2 N protein activates the NLRP3 signaling pathway, driving M1 macrophage polarization and the release of pro-inflammatory factors, thereby inducing alveolar epithelial cell apoptosis and worsening ARDS. Targeting this pathway may provide new therapeutic avenues for treating ARDS associated with SARS-CoV-2.

Oxidative stress controls lncRNA-mediated sow granulosa cell functions in a FoxO1-dependent manner

BACKGROUND

Oxidative stress (OS) is involved in low female fertility by altering multi-omics such as the transcriptome, miRome, and lncRNome in follicular cells and follicular fluid. However, the mechanism by which OS affects multi-omics dynamics remains largely unknown. Here, we report that OS induces lncRNome dynamics in sow granulosa cells (sGCs), which is partially dependent on the transcription factor activity of its effector, FoxO1.

RESULTS

A total of 2,283 putative FoxO recognition elements (FREs) were identified in the promoters of 394 lncRNAs, accounting for 91.20% (394/432) of the lncRNAs regulated by OS. ChIP and reporter assays showed that the effector FoxO1 mediated OS regulation of lncRNA transcription in a transcription factor activity-dependent manner. In sGCs, OS induces the transcription and function (e.g., apoptosis) of NORSF (non-coding RNA involved in sow fertility), a nuclear lncRNA involved in sGC function via FoxO1. Furthermore, FoxO1 has been identified as a transcriptional activator of NORSF in sGCs that interacts with the FRE motif of its promoter. Meanwhile, OS downregulates the transcription of CYP19A1, which encodes an essential enzyme for estrogen synthesis and 17β-estradiol (E2) release by sGCs via the FoxO1 and NORSF axis. Phenotypically, dysregulation of NORSF transcription caused by 2 novel adjacent transitions in the promoter leads to decreased sow fertility.

CONCLUSION

These results suggest a model of OS-stimulated lncRNome dynamics in sGCs and a new signaling pathway of OS that influences sGC function and sow fertility.

Bifidobacterium longum Metabolite Indole-3-Carboxaldehyde Blocks HDAC3 and Inhibits Macrophage NLRP3 Inflammasome Activation in Intestinal Ischemia/Reperfusion Injury

Indole-3-carboxaldehyde (3-IAld), a tryptophan metabolite derived from gut microbiota, has been reported to protect the intestine against radiation injury. This study aimed to clarify the role of Bifidobacterium longum (B. longum) and its metabolite indole-3-carboxaldehyde (3-IAld) in the pathophysiology of intestinal ischemia/reperfusion (II/R) injury. Superior mesenteric artery occlusion and reperfusion were performed to establish II/R mice, and pathological injury in II/R mice was evaluated. II/R mice showed impaired gut microbiota diversity and reduced abundance of B. longum in the intestines. Transplantation of B. longum mitigated II/R injury by protecting the integrity of the intestinal barrier and reducing inflammatory response. The 3-IAld level increased after transplantation of B. longum, and 3-IAld treatment inhibited the inflammatory response of bone marrow-derived macrophages (BMDM). Histone deacetylase 3 (HDAC3) was a target of 3-IAld, and HDAC3 was translocated to mitochondria to promote mitochondrial fatty acid oxidation (FAO) during macrophage inflammasome formation. HDAC3 overexpression promoted the formation of macrophage inflammasomes in intestinal tissues. Overall, this study confirmed the beneficial effects of B. longum in combating II/R injury through HDAC3-mediated control of mitochondrial FAO and macrophage inflammasome formation via 3-IAld.

ROS responsive nanozyme loaded with STING silencing for the treatment of sepsis-induced acute lung injury

Acute lung injury (ALI) is a common complication of sepsis and a leading cause of mortality in septic patients. Studies indicate that STING may play a crucial role in the pathogenesis of sepsis-induced ALI by interacting with the PARP-1/NLRP3 pathway. Therefore, targeting STING inhibition has potential as a novel therapeutic strategy for ALI. However, effective inhibition remains challenging due to the widespread expression of STING across various tissues. In this study, we developed a nanozyme-based drug delivery system, DSPE-TK-mPEG-MnO2@siSTING (abbreviated as DTmM@siSTING), using DSPE-TK-mPEG-MnO2 as the carrier, and characterized it via scanning electron microscopy, dynamic light scattering, nanoparticle size analysis, and gel electrophoresis. To evaluate the therapeutic effects of DTmM@siSTING, an in vitro ALI cell model and an in vivo ALI mouse model were established, assessing the nanozyme's impact on ROS levels, inflammatory responses, and the PARP-1/NLRP3 pathway in sepsis-induced ALI. Results demonstrated that DTmM@siSTING exhibited good physiological stability. In vitro, DTmM@siSTING significantly reduced ROS levels, myeloperoxidase activity, and expression of inflammatory cytokines, while also inhibiting PARP-1/NLRP3 pathway activation. In vivo experiments further revealed that DTmM@siSTING effectively delivered siSTING to the lungs, mitigating sepsis-induced ALI and associated inflammatory responses. Additionally, DTmM@siSTING displayed excellent biocompatibility. In summary, our findings suggest that DTmM@siSTING significantly enhances the therapeutic efficacy of siSTING, alleviating ALI by inhibiting ROS production, inflammatory responses, and activation of the PARP-1/NLRP3 pathway. This novel approach presents a promising therapeutic avenue for sepsis-induced ALI.

Inhibition of the FOXO1-ROCK1 axis mitigates cardiomyocyte injury under chronic hypoxia in Tetralogy of Fallot by maintaining mitochondrial quality control

INTRODUCTION

Persistent chronic myocardial hypoxia causes disturbances in mitochondrial quality control (MQC), ultimately leading to increased cardiomyocyte injury in patients with Tetralogy of Fallot (TOF). The present study aimed to identify the key effector molecules of cardiomyocyte injury under chronic hypoxia in TOF.

METHODS

Clinical data from TOF patients were collected and whole transcriptome sequencing was performed on myocardial samples. Chronic hypoxia models were established in cardiac-specific knockout mice and cardiomyocytes, and a series of molecular experiments were used to determine the specific mechanisms involved.

RESULTS

Clinical cohort data and whole-transcriptome sequencing analysis of myocardial samples from TOF patients revealed that forkhead box O1 (FOXO1) plays an important role in chronic hypoxic cardiomyocyte injury. In a model of chronic hypoxia established in FOXO1 cardiac-specific knockout mice and FOXO1 gene-deficient cardiomyocytes, the AMPK signaling pathway regulates the expression of FOXO1, which in turn disrupts MQC by regulating the transcriptional activation of Rho-associated protein kinase 1 (ROCK1), and increasing the production of mitochondrial ROS, thereby exacerbating damage to cardiomyocytes. Excessive reactive oxygen species (ROS) production during MQC dysfunction further activates Cox7a2L to increase the assembly of the respiratory chain supercomplex. In addition, we found that miR-27b-3p partially binds to the 3' untranslated region of FOXO1 to exert a protective effect.

CONCLUSIONS

Maintenance of MQC under chronic hypoxia is achieved through a series of injury-protection mechanisms, suggesting that FOXO1 inhibition may be crucial for future mitigation of chronic hypoxic cardiomyocyte injury in TOF.

Natural pachypodol integrated, lung targeted and inhaled lipid nanomedicine ameliorates acute lung injury via anti-inflammation and repairing lung barrier

Acute lung injury (ALI) or acute respiratory distress syndrome (ARDS) is a high-mortality disease caused by multiple disorders such as COVID-19, influenza, and sepsis. Current therapies mainly rely on the inhalation of nitric oxide or injection of pharmaceutical drugs (e.g., glucocorticoids); however, their toxicity, side effects, or administration routes limit their clinical application. In this study, pachypodol (Pac), a hydrophobic flavonol with anti-inflammatory effects, was extracted from Pogostemon cablin Benth and intercalated in liposomes (Pac@liposome, Pac-lipo) to improve its solubility, biodistribution, and bioavailability, aiming at enhanced ALI/ARDS therapy. Nanosized Pac-lipo was confirmed to have stable physical properties, good biodistribution, and reliable biocompatibility. In vitro tests proved that Pac-lipo has anti-inflammatory property and protective effects on endothelial and epithelial barriers in lipopolysaccharide (LPS)-induced macrophages and endothelial cells, respectively. Further, the roles of Pac-lipo were validated on treating LPS-induced ALI in mice. Pac-lipo showed better effects than did Pac alone on relieving ALI phenotypes: It significantly attenuated lung index, improved pulmonary functions, inhibited cytokine expression such as TNF-α, IL-6, IL-1β, and iNOS in lung tissues, alleviated lung injury shown by HE staining, reduced protein content and total cell number in bronchoalveolar lavage fluid, and repaired lung epithelial and vascular endothelial barriers. As regards the underlying mechanisms, RNA sequencing results showed that the effects of the drugs were associated with numerous immune- and inflammation-related signaling pathways. Molecular docking and western blotting demonstrated that Pac-lipo inhibited the activation of the TLR4-MyD88-NF-κB/MAPK signaling pathway. Taken together, for the first time, our new drug (Pac-lipo) ameliorates ALI via inhibition of TLR4-MyD88-NF-κB/MAPK pathway-mediated inflammation and disruption of lung barrier. These findings may provide a promising strategy for ALI treatment in the clinic.

Novel Therapeutic Target for ALI/ARDS: Forkhead Box Transcription Factors

ALI/ARDS can be a pulmonary manifestation of a systemic inflammatory response or a result of overexpression of the body's normal inflammatory response involving various effector cells, cytokines, and inflammatory mediators, which regulate the body's immune response through different signalling pathways. Forkhead box transcription factors are evolutionarily conserved transcription factors that play a crucial role in various cellular processes, such as cell cycle progression, proliferation, differentiation, migration, metabolism, and DNA damage response. Transcription factors control protein synthesis by regulating gene transcription levels, resulting in diverse biological outcomes. The Fox family plays a role in activating or inhibiting the expression of various molecules related to ALI/ARDS through phosphorylation, acetylation/deacetylation, and control of multiple signalling pathways. An in-depth analysis of the integrated Fox family's role in ALI/ARDS can aid in the development of potential diagnostic and therapeutic targets for the condition.

The involvement of HDAC3 in the pathogenesis of lung injury and pulmonary fibrosis

Acute lung injury (ALI) and its severe counterpart, acute respiratory distress syndrome (ARDS), are critical respiratory conditions with high mortality rates due primarily to acute and intense pulmonary inflammation. Despite significant research advances, effective pharmacological treatments for ALI and ARDS remain unavailable, highlighting an urgent need for therapeutic innovation. Notably, idiopathic pulmonary fibrosis (IPF) is a chronic, progressive disease characterized by the irreversible progression of fibrosis, which is initiated by repeated damage to the alveolar epithelium and leads to excessive extracellular matrix deposition. This condition is further complicated by dysregulated tissue repair and fibroblast dysfunction, exacerbating tissue remodeling processes and promoting progression to terminal pulmonary fibrosis. Similar to that noted for ALI and ARDS, treatment options for IPF are currently limited, with no specific drug therapy providing a cure. Histone deacetylase 3 (HDAC3), a notable member of the HDAC family with four splice variants (HD3α, -β, -γ, and -δ), plays multiple roles. HDAC3 regulates gene transcription through histone acetylation and adjusts nonhistone proteins posttranslationally, affecting certain mitochondrial and cytoplasmic proteins. Given its unique structure, HDAC3 impacts various physiological processes, such as inflammation, apoptosis, mitochondrial homeostasis, and macrophage polarization. This article explores the intricate role of HDAC3 in ALI/ARDS and IPF and evaluates its therapeutic potential the treatment of these severe pulmonary conditions.

Loureirin C improves mitochondrial function by promoting NRF2 nuclear translocation to attenuate oxidative damage caused by renal ischemia-reperfusion injury

Acute kidney injury (AKI) is a common clinical syndrome worldwide, with no effective treatment strategy. Renal ischemia-reperfusion (IR) injury is one of the main AKI features, and the excessive reactive oxygen species (ROS) production during reperfusion causes severe oxidative damage to the kidney. Loureirin C (LC), an active ingredient in the traditional Chinese medicine Chinese dragon's blood, possesses excellent antioxidative properties, but its role in renal IR injury is not clear. In this study, we evaluated the protective effects of LC against renal IR injury in vivo and in vitro by establishing a mice renal IR injury model and a human proximal renal tubular epithelial cell (HK-2) hypoxia/reoxygenation (HR) model. We found that LC ameliorated renal function and tissue structure injury and inhibited renal oxidative stress and ferroptosis in vivo. In vitro, LC scavenged ROS and attenuated mitochondrial dysfunction in HK-2 cells, thereby inhibiting oxidative cellular injury. Furthermore, we found that LC effectively promoted nuclear factor erythroid 2-related factor 2 (NRF2) nuclear translocation and activated downstream target genes heme oxygenase 1 (HO-1) and NADPH quinone oxidoreductase-1 (NQO-1) to enhance cellular antioxidant function. Moreover, NRF2 knockdown and pharmacological inhibition of NRF2 partially eliminated the protective effect of LC. These results confirm that LC can effectively inhibit renal IR injury, and the mechanism may be associated with NRF2 activation by LC.

Relationship between ferroptosis and mitophagy in acute lung injury: a mini-review

Acute lung injury (ALI) is one of the most deadly and prevalent diseases in the intensive care unit. Ferroptosis and mitophagy are pathological mechanisms of ALI. Ferroptosis aggravates ALI, whereas mitophagy regulates ALI. Ferroptosis and mitophagy are both closely related to reactive oxygen species (ROS). Mitophagy can regulate ferroptosis, but the specific relationship between ferroptosis and mitophagy is still unclear. This study summarizes previous research findings on ferroptosis and mitophagy, revealing their involvement in ALI. Examining the functions of mTOR and NLPR3 helps clarify the connection between ferroptosis and mitophagy in ALI, with the goal of establishing a theoretical foundation for potential therapeutic approaches in the future management of ALI.

Neutrophil extracellular traps trigger alveolar epithelial cell necroptosis through the cGAS-STING pathway during acute lung injury in mice

Extensive loss of alveolar epithelial cells (AECs) undergoing necroptosis is a crucial mechanism of acute lung injury (ALI), but its triggering mechanism needs to be thoroughly investigated. Neutrophil extracellular traps (NETs) play a significant role in ALI. However, the effect of NETs on AECs' death has not been clarified. Our study found that intratracheal instillation of NETs disrupted lung tissue structure, suggesting that NETs could induce ALI in mice. Moreover, we observed that NETs could trigger necroptosis of AECs in vivo and in vitro. The phosphorylation levels of RIPK3 and MLKL were increased in MLE12 cells after NETs treatment (P < 0.05). Mechanistically, NETs taken up by AECs through endocytosis activated the cGAS-STING pathway and triggered AECs necroptosis. The expression of cGAS, STING, TBK1 and IRF3 were increased in MLE12 cells treated with NETs (P < 0.05). Furthermore, the cGAS inhibitor RU.521 inhibited NETs-triggered AECs necroptosis and alleviated the pulmonary damage induced by NETs in mice. In conclusion, our study demonstrates that NETs taken up by AECs via endocytosis can activate the cGAS-STING pathway and trigger AECs necroptosis to promote ALI in mice. Our findings indicate that targeting the NETs/cGAS-STING/necroptosis pathway in AECs is an effective strategy for treating ALI.

BRD3308 suppresses macrophage oxidative stress and pyroptosis via upregulating acetylation of H3K27 in sepsis-induced acute lung injury

Background

Sepsis-induced acute lung injury (ALI) leads to severe hypoxemia and respiratory failure, contributing to poor prognosis in septic patients. Endotoxin dissemination triggers oxidative stress and the release of inflammatory cytokines in macrophages, initiating diffuse alveolar damage. The role of epigenetic histone modifications in organ injury is increasingly recognized. The present study aimed to investigate the use of a histone modification inhibitor to alleviate sepsis-induced ALI, revealing a new strategy for improving sepsis patient survival.

Methods

In vivo models of ALI were established through the intraperitoneal injection of lipopolysaccharide and cecal ligation and puncture surgery. Furthermore, the disease process was simulated in vitro by stimulating Tamm-Horsfall protein-1 (THP-1) cells with lipopolysaccharide. Hematoxylin and eosin staining, blood gas analysis and pulmonary function tests were utilized to assess the extent of lung tissue damage. Western blot analysis, real-time polymerase chain reaction, enzyme-linked immunosorbent assay and immunofluorescence were used to measure the levels and distribution of the indicated indicators within cells and tissues. Reactive oxygen species and autophagic flux alterations were detected using specific probes.

Results

BRD3308, which is a inhibitor of histone deacetylase 3, improved lung tissue damage, inflammatory infiltration and edema in ALI by inhibiting Nod-like receptor protein3-mediated pyroptosis in macrophages. By upregulating autophagy, BRD3308 improved the disruption of redox balance in macrophages and reduced the accumulation of reactive oxygen species. Mechanistically, BRD3308 inhibited histone deacetylase 3 activity by binding to it and altering its conformation. Following histone deacetylase 3 inhibition, acetylation of H3K27 was significantly increased. Moreover, the increase in H3K27Ac led to the upregulation of autophagy-related gene 5, a key component of autophagosomes, thereby activating autophagy.

Conclusions

BRD3308 inhibits oxidative stress and pyroptosis in macrophages by modulating histone acetylation, thereby preventing sepsis-induced ALI. The present study provides a potential strategy and theoretical basis for the clinical treatment of sepsis-induced ALI.

Deciphering the dynamics: Exploring the impact of mechanical forces on histone acetylation

Living cells navigate a complex landscape of mechanical cues that influence their behavior and fate, originating from both internal and external sources. At the molecular level, the translation of these physical stimuli into cellular responses relies on the intricate coordination of mechanosensors and transducers, ultimately impacting chromatin compaction and gene expression. Notably, epigenetic modifications on histone tails govern the accessibility of gene-regulatory sites, thereby regulating gene expression. Among these modifications, histone acetylation emerges as particularly responsive to the mechanical microenvironment, exerting significant control over cellular activities. However, the precise role of histone acetylation in mechanosensing and transduction remains elusive due to the complexity of the acetylation network. To address this gap, our aim is to systematically explore the key regulators of histone acetylation and their multifaceted roles in response to biomechanical stimuli. In this review, we initially introduce the ubiquitous force experienced by cells and then explore the dynamic alterations in histone acetylation and its associated co-factors, including HDACs, HATs, and acetyl-CoA, in response to these biomechanical cues. Furthermore, we delve into the intricate interactions between histone acetylation and mechanosensors/mechanotransducers, offering a comprehensive analysis. Ultimately, this review aims to provide a holistic understanding of the nuanced interplay between histone acetylation and mechanical forces within an academic framework.

Gut-derived memory γδ T17 cells exacerbate sepsis-induced acute lung injury in mice

Sepsis is a critical global health concern linked to high mortality rates, often due to acute lung injury (ALI)/acute respiratory distress syndrome (ARDS). While the gut-lung axis involvement in ALI is recognized, direct migration of gut immune cells to the lung remains unclear. Our study reveals sepsis-induced migration of γδ T17 cells from the small intestine to the lung, triggering an IL-17A-dominated inflammatory response in mice. Wnt signaling activation in alveolar macrophages drives CCL1 upregulation, facilitating γδ T17 cell migration. CD44+ Ly6C- IL-7Rhigh CD8low cells are the primary migratory subtype exacerbating ALI. Esketamine attenuates ALI by inhibiting pulmonary Wnt/β-catenin signaling-mediated migration. This work underscores the pivotal role of direct gut-to-lung memory γδ T17 cell migration in septic ALI and clarifies the importance of localized IL-17A elevation in the lung.

Fasudil attenuates oxidative stress-induced partial epithelial-mesenchymal transition of tubular epithelial cells in hyperuricemic nephropathy via activating Nrf2

Anti-partial epithelial-mesenchymal transition (pEMT) treatment of renal tubular epithelial cells (TECs) represents a promising therapeutic approach. Hyperuricemia nephropathy (HN) arises as a consequence of hyperuricemia (HUA)-induced tubulointerstitial fibrosis (TIF). Studies have suggested that the Ras homolog member A (RhoA)/Rho-associated kinase (ROCK) pathway is a crucial signaling transduction system in renal fibrosis. Fasudil, a RhoA/ROCK inhibitor, has exhibited the potential to prevent fibrosis progress. However, its impact on the pEMT of TECs in HN remains unclear. Here, an HN rat model and an uric acid (UA)-stimulated human kidney 2 (HK2) cell model were established and treated with Fasudil to explore its effects. Furthermore, the underlying mechanism of action involved in the attenuation of pEMT in TECs by Fasudil during HN was probed by using multiple molecular approaches. The HN rat model exhibited significant renal dysfunction and histopathological damage, whereas in vitro and in vivo experiments further confirmed the pEMT status accompanied by RhoA/ROCK pathway activation and oxidative stress in tubular cells exposed to UA. Notably, Fasudil ameliorated these pathological changes, and this was consistent with the trend of ROCK silencing in vitro. Mechanistically, we identified the Neh2 domain of nuclear factor erythroid 2-related factor 2 (Nrf2) as a target of Fasudil for the first time. Fasudil targets Nrf2 activation and antagonizes oxidative stress to attenuate the pEMT of TECs in HN. Our findings suggest that Fasudil attenuates oxidative stress-induced pEMT of TECs in HN by targeting Nrf2 activation. Thus, Fasudil is a potential therapeutic agent for the treatment of HN.

KLF13 Attenuates Lipopolysaccharide-Induced Alveolar Epithelial Cell Damage by Regulating Mitochondrial Quality Control via Binding PGC-1α

Sepsis is a clinically life-threatening syndrome, and acute lung injury is the earliest and most serious complication. We aimed to assess the role of kruppel-like factor 13 (KLF13) in lipopolysaccharide (LPS)-induced human alveolar type II epithelial cell damage and to reveal the possible mechanism related to peroxisome proliferator-activated receptor-γ co-activator 1-α (PGC-1α). In LPS-treated A549 cells with or without KLF13 overexpression or PGC-1α knockdown, cell viability was measured by a cell counting kit-8 assay. Enzyme-linked immunosorbent assay kits detected the levels of inflammatory factors, and terminal deoxynucleotidyl transferase dUTP nick-end labeling staining measured cell apoptosis. Besides, mitochondrial reactive oxygen species (MitoSOX) and mitochondrial membrane potential were detected using MitoSOX red- and JC-1 staining. Expression of proteins related to mitochondrial quality control (MQC) was evaluated by western blot. Co-immunoprecipitation (Co-IP) assay was used to analyze the interaction between KLF13 and PGC-1α. Results indicated that KLF13 was highly expressed in LPS-treated A549 cells. KLF13 upregulation elevated the viability and reduced the levels of inflammatory factors in A549 cells exposed to LPS. Moreover, KLF13 gain-of-function inhibited LPS-induced apoptosis of A549 cells, accompanied by upregulated BCL2 expression and downregulated Bax and cleaved caspase3 expression. Furthermore, MQC was improved by KLF13 overexpression, as evidenced by decreased MitoSOX, JC-1 monomers and increased JC-1 aggregates, coupled with the changes of proteins related to MQC. In addition, Co-IP assay confirmed the interaction between KLF13 and PGC-1α. PGC-1α deficiency restored the impacts of KLF13 upregulation on the inflammation, apoptosis, and MQC in LPS-treated A549 cells. In conclusion, KLF13 attenuated LPS-induced alveolar epithelial cell inflammation and apoptosis by regulating MQC via binding PGC-1α.

Advances in nanomaterial-targeted treatment of acute lung injury after burns

Acute lung injury (ALI) is a common complication in patients with severe burns and has a complex pathogenesis and high morbidity and mortality rates. A variety of drugs have been identified in the clinic for the treatment of ALI, but they have toxic side effects caused by easy degradation in the body and distribution throughout the body. In recent years, as the understanding of the mechanism underlying ALI has improved, scholars have developed a variety of new nanomaterials that can be safely and effectively targeted for the treatment of ALI. Most of these methods involve nanomaterials such as lipids, organic polymers, peptides, extracellular vesicles or cell membranes, inorganic nanoparticles and other nanomaterials, which are targeted to reach lung tissues to perform their functions through active targeting or passive targeting, a process that involves a variety of cells or organelles. In this review, first, the mechanisms and pathophysiological features of ALI occurrence after burn injury are reviewed, potential therapeutic targets for ALI are summarized, existing nanomaterials for the targeted treatment of ALI are classified, and possible problems and challenges of nanomaterials in the targeted treatment of ALI are discussed to provide a reference for the development of nanomaterials for the targeted treatment of ALI.

Hydrogen alleviates impaired lung epithelial barrier in acute respiratory distress syndrome via inhibiting Drp1-mediated mitochondrial fission through the Trx1 pathway

Acute respiratory distress syndrome (ARDS) is an acute and severe clinical complication lacking effective therapeutic interventions. The disruption of the lung epithelial barrier plays a crucial role in ARDS pathogenesis. Recent studies have proposed the involvement of abnormal mitochondrial dynamics mediated by dynamin-related protein 1 (Drp1) in the mechanism of impaired epithelial barrier in ARDS. Hydrogen is an anti-oxidative stress molecule that regulates mitochondrial function via multiple signaling pathways. Our previous study confirmed that hydrogen modulated oxidative stress and attenuated acute pulmonary edema in ARDS by upregulating thioredoxin 1 (Trx1) expression, but the exact mechanism remains unclear. This study aimed to investigate the effects of hydrogen on mitochondrial dynamics both in vivo and in vitro. Our study revealed that hydrogen inhibited lipopolysaccharide (LPS)-induced phosphorylation of Drp1 (at Ser616), suppressed Drp1-mediated mitochondrial fission, alleviated epithelial tight junction damage and cell apoptosis, and improved the integrity of the epithelial barrier. This process was associated with the upregulation of Trx1 in lung epithelial tissues of ARDS mice by hydrogen. In addition, hydrogen treatment reduced the production of reactive oxygen species in LPS-induced airway epithelial cells (AECs) and increased the mitochondrial membrane potential, indicating that the mitochondrial dysfunction was restored. Then, the expression of tight junction proteins occludin and zonula occludens 1 was upregulated, and apoptosis in AECs was alleviated. Remarkably, the protective effects of hydrogen on the mitochondrial and epithelial barrier were eliminated after applying the Trx1 inhibitor PX-12. The results showed that hydrogen significantly inhibited the cell apoptosis and the disruption of epithelial tight junctions, maintaining the integrity of the epithelial barrier in mice of ARDS. This might be related to the inhibition of Drp1-mediated mitochondrial fission through the Trx1 pathway. The findings of this study provided a new theoretical basis for the application of hydrogen in the clinical treatment of ARDS.

Mitochondrial quality control in human health and disease

Mitochondria, the most crucial energy-generating organelles in eukaryotic cells, play a pivotal role in regulating energy metabolism. However, their significance extends beyond this, as they are also indispensable in vital life processes such as cell proliferation, differentiation, immune responses, and redox balance. In response to various physiological signals or external stimuli, a sophisticated mitochondrial quality control (MQC) mechanism has evolved, encompassing key processes like mitochondrial biogenesis, mitochondrial dynamics, and mitophagy, which have garnered increasing attention from researchers to unveil their specific molecular mechanisms. In this review, we present a comprehensive summary of the primary mechanisms and functions of key regulators involved in major components of MQC. Furthermore, the critical physiological functions regulated by MQC and its diverse roles in the progression of various systemic diseases have been described in detail. We also discuss agonists or antagonists targeting MQC, aiming to explore potential therapeutic and research prospects by enhancing MQC to stabilize mitochondrial function.

Research hotspots and evolving trends of barrier dysfunction in acute lung injury and acute respiratory distress syndrome

Endothelial and epithelial barrier dysfunction due to increased permeability and heightened inflammatory reactions influences the emergence of acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). Nevertheless, bibliometric research comparing endothelial and epithelial barriers is limited. Therefore, this bibliometric study analyzed the Web of Science Core Collection (WoSCC) of the Science Citation Index Expanded literature to explore present research priorities and development tendencies within this field. We conducted a comprehensive search (October 18, 2023) on WoSCC from January 1, 2010, to October 18, 2023, focusing on articles related to endothelial and epithelial barriers in ALI and ARDS. Retrieved data were visualized and analyzed using R-bibliometrix, VOS viewer 1.6.19, and CiteSpace 6.2. R4. Functional enrichment analysis of gene targets identified in the keyword list using Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene ontology databases, and based on the STRING database to construct a PPI network to predict core genes. A total of 941 original articles and reviews were identified. The United States had the highest number of publications and citations and the highest H-index and G-index. According to the Collaboration Network Analysis graph, the United States and China had the strongest collaboration. Birukova AA had the most publications and citations among all authors, while eight of the top ten institutions with mediator centrality were located in the United States. The American Journal of Physiology-Lung Cellular and Molecular Physiology was the leading journal and had the most well-established publication on endothelial and epithelial barriers in ALI and ARDS. Bibliometric analysis revealed that the most frequently used keywords were acute lung injury, ARDS, activation, expression, and inflammation. RHOA appeared most frequently among gene-related keywords, and the PI3K-AKT signaling pathway had the highest count in KEGG pathway enrichment. Research on endothelial versus epithelial barriers in ALI and ARDS remains preliminary. This bibliometric study examined cooperative network connections among countries, authors, journals, and network associations in the cited references. Investigation of the functions of the endothelial and epithelial barriers in ALI/ARDS associated with COVID-19 has recently gained significant attention.

Mitochondrial (mt)DNA-cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) signaling promotes pyroptosis of macrophages via interferon regulatory factor (IRF)7/IRF3 activation to aggravate lung injury during severe acute pancreatitis

BACKGROUND

Macrophage proinflammatory activation contributes to the pathology of severe acute pancreatitis (SAP) and, simultaneously, macrophage functional changes, and increased pyroptosis/necrosis can further exacerbate the cellular immune suppression during the process of SAP, where cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) plays an important role. However, the function and mechanism of cGAS-STING in SAP-induced lung injury (LI) remains unknown.

METHODS

Lipopolysaccharide (LPS) was combined with caerulein-induced SAP in wild type, cGAS -/- and sting -/- mice. Primary macrophages were extracted via bronchoalveolar lavage and peritoneal lavage. Ana-1 cells were pretreated with LPS and stimulated with nigericin sodium salt to induce pyroptosis in vitro.

RESULTS

SAP triggered NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3) inflammasome activation-mediated pyroptosis of alveolar and peritoneal macrophages in mouse model. Knockout of cGAS/STING could ameliorate NLRP3 activation and macrophage pyroptosis. In addition, mitochondrial (mt)DNA released from damaged mitochondria further induced macrophage STING activation in a cGAS- and dose-dependent manner. Upregulated STING signal can promote NLRP3 inflammasome-mediated macrophage pyroptosis and increase serum interleukin (IL)-6, IL-1β, and tumor necrosis factor (TNF)-α levels and, thus, exacerbate SAP-associated LI (SAP-ALI). Downstream molecules of STING, IRF7, and IRF3 connect the mtDNA-cGAS-STING axis and the NLRP3-pyroptosis axis.

CONCLUSIONS

Negative regulation of any molecule in the mtDNA-cGAS-STING-IRF7/IRF3 pathway can affect the activation of NLRP3 inflammasomes, thereby reducing macrophage pyroptosis and improving SAP-ALI in mouse model.

Vaporization of perfluorocarbon attenuates sea-water-drowning-induced acute lung injury by deactivating the NLRP3 inflammasomes in canines

Seawater-drowning-induced acute lung injury (SD-ALI) is a life-threatening disorder characterized by increased alveolar-capillary permeability, an excessive inflammatory response, and refractory hypoxemia. Perfluorocarbons (PFCs) are biocompatible compounds that are chemically and biologically inert and lack toxicity as oxygen carriers, which could reduce lung injury in vitro and in vivo. The aim of our study was to explore whether the vaporization of PFCs could reduce the severity of SD-ALI in canines and investigate the underlying mechanisms. Eighteen beagle dogs were randomly divided into three groups: the seawater drowning (SW), perfluorocarbon (PFC), and control groups. The dogs in the SW group were intratracheally administered seawater to establish the animal model. The dogs in the PFC group were treated with vaporized PFCs. Probe-based confocal laser endomicroscopy (pCLE) was performed at 3 h. The blood gas, volume air index (VAI), pathological changes, and wet-to-dry (W/D) lung tissue ratios were assessed. The expression of heme oxygenase-1 (HO-1), nuclear respiratory factor-1 (NRF1), and NOD-like receptor family pyrin domain containing-3 (NLRP3) inflammasomes was determined by means of quantitative real-time polymerase chain reaction (qRT-PCR) and immunological histological chemistry. The SW group showed higher lung injury scores and W/D ratios, and lower VAI compared to the control group, and treatment with PFCs could reverse the change of lung injury score, W/D ratio and VAI. PFCs deactivated NLRP3 inflammasomes and reduced the release of caspase-1, interleukin-1β (IL-1β), and interleukin-18 (IL-18) by enhancing the expression of HO-1 and NRF1. Our results suggest that the vaporization of PFCs could attenuate SD-ALI by deactivating NLRP3 inflammasomes via the HO-1/NRF1 pathway.

A deep insight into ferroptosis in lung disease: facts and perspectives

In the last decade, ferroptosis has received much attention from the scientific research community. It differs from other modes of cell death at the morphological, biochemical, and genetic levels. Ferroptosis is mainly characterized by non-apoptotic iron-dependent cell death caused by iron-dependent lipid peroxide excess and is accompanied by abnormal iron metabolism and oxidative stress. In recent years, more and more studies have shown that ferroptosis is closely related to the occurrence and development of lung diseases. COPD, asthma, lung injury, lung fibrosis, lung cancer, lung infection and other respiratory diseases have become the third most common chronic diseases worldwide, bringing serious economic and psychological burden to people around the world. However, the exact mechanism by which ferroptosis is involved in the development and progression of lung diseases has not been fully revealed. In this manuscript, we describe the mechanism of ferroptosis, targeting of ferroptosis related signaling pathways and proteins, summarize the relationship between ferroptosis and respiratory diseases, and explore the intervention and targeted therapy of ferroptosis for respiratory diseases.

Neutrophil Extracellular Traps Upregulate p21 and Suppress Cell Cycle Progression to Impair Endothelial Regeneration after Inflammatory Lung Injury

Background: Sepsis is a major cause of ICU admissions, with high mortality and morbidity. The lungs are particularly vulnerable to infection and injury, and restoration of vascular endothelial homeostasis after injury is a crucial determinant of outcome. Neutrophil extracellular trap (NET) release strongly correlates with the severity of lung tissue damage. However, little is known about whether NETs affect endothelial cell (EC) regeneration and repair. Methods: Eight- to ten-week-old male C57BL/6 mice were injected intraperitoneally with a sublethal dose of LPS to induce acute lung inflammatory injury or with PBS as a control. Blood samples and lung tissues were collected to detect NET formation and lung endothelial cell proliferation. Human umbilical vein endothelial cells (HUVECs) were used to determine the role of NETs in cell cycle progression in vitro. Results: Increased NET formation and impaired endothelial cell proliferation were observed in mice with inflammatory lung injury following septic endotoxemia. Degradation of NETs with DNase I attenuated lung inflammation and facilitated endothelial regeneration. Mechanistically, NETs induced p21 upregulation and cell cycle stasis to impair endothelial repair. Conclusions: Our findings suggest that NET formation impairs endothelial regeneration and vascular repair through the induction of p21 and cell cycle arrest during inflammatory lung injury.

LGK974 suppresses the formation of deep vein thrombosis in mice with sepsis

BACKGROUND

Sepsis is a disorder characterized by host inflammation and is caused by systemic infection. The inflammatory cytokine storm results in platelet overactivation, leading to coagulation dysfunction and thrombosis, but the underlying mechanism remains poorly understood. Recent evidence has shown that the Wnt/β-catenin signaling pathway is related to sepsis, but its role and mechanism in sepsis complicated with deep vein thrombosis (DVT) are unclear.

METHODS

In this study, a cecal ligation and puncture (CLP)-induced sepsis model and DVT mouse model were constructed by inferior vena cava ligation. The levels of serum inflammatory factors and adhesion molecules were measured in each group, and the thrombus weight and size, hematoxylin-eosin staining, collagen fiber tissue, and transcriptome of the venous wall were analyzed. The activation of the Wnt/β-catenin signal was evaluated by quantitative real-time polymerase chain reaction, Western blotting, ELISA, and immunohistochemical and immunofluorescence methods.

RESULTS

Sepsis significantly promoted the formation of venous wall collagen fibers and DVT. In addition, Porcn significantly upregulated and activated the Wnt/β-catenin signaling pathway in sepsis mouse models with DVT. In contrast, the Wnt signaling inhibitor LGK974 was found to improve the survival rate, decrease thrombosis, and inhibit the expression of inflammation and adhesion molecules in sepsis mice with DVT. Therefore, activation of the Wnt/β-catenin signal may promote the formation of DVT in sepsis mice.

CONCLUSIONS

LGK974 protects against DVT formation in sepsis mice by inhibiting the activation of the Wnt/β-catenin signal and down-regulating the production of proinflammatory cytokines, PAI-1, and adhesion molecules. LGK974 may be a new candidate for the treatment of sepsis complicated with DVT.

Inhibition of METTL3 alleviated LPS-induced alveolar epithelial cell apoptosis and acute lung injury via restoring neprilysin expression

AIMS

To investigate the role and mechanisms of methyltransferase-like 3 (METTL3) in the pathogenesis of lipopolysaccharide (LPS)-induced acute lung injury (ALI).

MAIN METHODS

LPS intratracheally instillation was applied in alveolar epithelial cell METTL3 conditional knockout (METTL3-CKO) mice and their wild-type littermates. In addition, METTL3 inhibitor STM2457 was used. LPS treatment on mouse lung epithelial 12 (MLE-12) cell was applied to establish an in vitro model of LPS-induced ALI. H&E staining, lung wet-to-dry ratio, and total broncho-alveolar lavage fluid (BALF) concentrations were used to evaluate lung injury. Overall, the m6A level was determined with the m6A RNA Methylation Quantification Kit and dot blot assay. Expression of METTL3 and neprilysin were measured with immunohistochemistry, immunofluorescence, immunofluorescence-fluorescence in situ hybridization, and western blot. Apoptosis was detected with TUNEL, western blot, and flow cytometry. The interaction of METTL3 and neprilysin was determined with RIP-qPCR and MeRIP.

KEY FINDINGS

METTL3 expression and apoptosis were increased in alveolar epithelial cells of mice treated with LPS, and METTL3-CKO or METTL3 inhibitor STM2457 could alleviate apoptosis and LPS-induced ALI. In MLE-12 cells, LPS-Induced METTL3 expression and apoptosis. Knockdown of METTL3 alleviated, while overexpression of METTL3 exacerbated LPS-induced apoptosis. LPS treatment reduced neprilysin expression, the intervention of neprilysin expression negatively regulated apoptosis without affecting METTL3 expression, and mitigated the promoting effect of METTL3 on LPS-induced apoptosis. Additionally, METTL3 could bind to the mRNA of neprilysin, and reduce its expression.

SIGNIFICANCE

Our findings revealed that inhibition of METTL3 could exert anti-apoptosis and ALI-protective effects via restoring neprilysin expression.

Mitochondrial transfer between cell crosstalk - An emerging role in mitochondrial quality control

Intercellular signaling and component conduction are essential for multicellular organisms' homeostasis, and mitochondrial transcellular transport is a key example of such cellular component exchange. In physiological situations, mitochondrial transfer is linked with biological development, energy coordination, and clearance of harmful components, remarkably playing important roles in maintaining mitochondrial quality. Mitochondria are engaged in many critical biological activities, like oxidative metabolism and biomolecular synthesis, and are exclusively prone to malfunction in pathological processes. Importantly, severe mitochondrial damage will further amplify the defects in the mitochondrial quality control system, which will mobilize more active mitochondrial transfer, replenish exogenous healthy mitochondria, and remove endogenous damaged mitochondria to facilitate disease outcomes. This review explores intercellular mitochondrial transport in cells, its role in cellular mitochondrial quality control, and the linking mechanisms in cellular crosstalk. We also describe advances in therapeutic strategies for diseases that target mitochondrial transfer.

Bezafibrate attenuates acute lung injury by preserving mitochondrial dynamics equilibrium in pulmonary epithelial cells

Acute lung injury (ALI) serves as a common life-threatening clinical syndrome with high mortality rates, which is characterized by disturbed mitochondrial dynamics in pulmonary epithelial barrier. Peroxisome proliferator-activated receptor-γ (PPAR-γ) is one of the critical nuclear receptors, exerting important roles in preserving mitochondrial dynamics equilibrium. Previous studies have suggested that bezafibrate (BEZ), a PPAR-γ agonist, could improve obesity and insulin resistance. In the present study, we explored whether bezafibrate could attenuate lipopolysaccharide (LPS)-induced ALI in vivo and in vitro. Using C57BL/6 mice exposed to LPS, we observed that BEZ pretreatment (100 mg/kg) for 7 days decreased lung pathologic injury, reduced oxidative stress, suppressed inflammation and apoptosis, accompanied by shifting the dynamic course of mitochondria from fission into fusion. Meanwhile, we observed that BEZ could reverse the inhibition of PPAR-γ in lung tissues from LPS-treated mice. In vitro experiments also disclosed that BEZ could improve cell viability in primary pulmonary epithelial cells in a concentration-dependent manner. And BEZ (80 μM) treatment could not only inhibit oxidative stress but also preserve mitochondrial dynamics equilibrium in primary pulmonary epithelial cells. However, PPAR-γ knockdown partially abolished BEZ-mediated antioxidation and completely offset its regulatory effects on mitochondrial dynamics in primary pulmonary epithelial cells. In PPAR-γ-deficient mice, BEZ lost its pulmonary protection including anti-inflammatory and antioxidative effects in mice with ALI. Taken together, BEZ could attenuate ALI by preserving mitochondrial dynamics equilibrium in pulmonary epithelial cells in a PPAR-γ-dependent manner.