Macrophage Sprouty4 deficiency diminishes sepsis-induced acute lung injury in mice

Essential oil from Cinnamomum cassia Presl bark regulates macrophage polarization and ameliorates lipopolysaccharide-induced acute lung injury through TLR4/MyD88/NF-κB pathway

BACKGROUND

Cinnamomum cassia Presl, a traditional Chinese medicine recorded in "Shennong's Herbal Classic," has been historically used to treat respiratory diseases and is employed to address inflammation. The essential oil derived from Cinnamomum cassia bark is a primary anti-inflammatory agent. However, there remains ambiguity regarding the chemical composition of cinnamon bark essential oil (BCEO), its principal anti-inflammatory components, and their potential efficacy in typical inflammatory respiratory conditions, such as acute lung injury (ALI).

PURPOSE

This study aimed to unveil the chemical composition of BCEO. In addition, the mechanism of action of BCEO in ameliorating ALI and regulating macrophage polarization through the TLR4/MyD88/NF-κB pathway was elucidated.

METHODS

BCEO was extracted using supercritical fluid extraction (SFE) and characterized through gas chromatography-mass spectrometry (GC-MS) analysis. Acute oral toxicity was observed in C57BL/6 J mice. The pharmacological effects and underlying mechanisms of BCEO were evaluated in a mouse model of ALI, which was induced by administering 5 mg/kg of lipopolysaccharide (LPS) through intratracheal instillation.

RESULTS

GC-MS analysis revealed 99.08% of the constituents of BCEO. The primary components of BCEO were trans-cinnamaldehyde, o-methoxycinnamaldehyde, (+)-α-muurolene, δ-cadinene, and copaene. Oral acute toxicity tests indicated that the maximum tolerated dose of BCEO was 12 g/kg/day. BCEO treatment significantly reduced lung W/D ratio, total protein concentration in BALF, levels of TNF-α, IL-6, and IL-1β in BALF, WBC count and NEU% in peripheral blood, and lung histological damage. Pulmonary function, IL-10 levels, and LYM% in peripheral blood also showed improvement. BCEO effectively decreased the proportion of M1 phenotype macrophages in BALF, M1/M2 ratio, and apoptotic cells in the lung tissue while increasing the proportion of M2 phenotype macrophages in BALF. Furthermore, BCEO treatment led to reduced protein and mRNA levels of TLR4, MyD88, and p-p65, alongside increased p65 expression, suggesting its potential to impede the TLR4/MyD88/NF-κB signaling pathway.

CONCLUSION

SFE-extracted BCEO or its major constituents could serve as a viable treatment for ALI by reducing lung inflammation, improving pulmonary function, and protecting against LPS-induced ALI in mice. This therapeutic effect is achieved by inhibiting M1 macrophage polarization, promoting M2 macrophage polarization, and suppressing the TLR4/MyD88/NF-κB signaling pathway.

Regulation of YAP translocation by myeloid Pten deficiency alleviates acute lung injury via inhibition of oxidative stress and inflammation

BACKGROUND

Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) is intricately involved in modulating the inflammatory response in acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). Nevertheless, the myeloid PTEN governing Hippo-YAP pathway mediated oxidative stress and inflammation in lipopolysaccharide (LPS)-induced ALI remains to be elucidate.

METHODS

The floxed Pten (PtenFL/FL) and myeloid-specific Pten knockout (PtenM-KO) mice were intratracheal instill LPS (5 mg/kg) to establish ALI, then Yap siRNA mix with the mannose-conjugated polymers was used to knockdown endogenous macrophage YAP in some PtenM-KO mice before LPS challenged. The bone marrow-derived macrophages (BMMs) from PtenFL/FL and PtenM-KO mice were obtained, and BMMs were transfected with CRISPR/Cas9-mediated glycogen synthase kinase 3 Beta (GSK3β) knockout (KO) or Yes-associated protein (YAP) KO vector subjected to LPS (100 ng/ml) challenged or then cocultured with MLE12 cells.

RESULTS

Here, our findings demonstrate that myeloid-specific PTEN deficiency exerts a protective against LPS-induced oxidative stress and inflammation dysregulated in ALI model. Moreover, ablation of the PTEN-YAP axis in macrophages results in reduced nuclear factor-E2-related factor-2 (NRF2) expression, a decrease in antioxidant gene expression, augmented levels of free radicals, lipid and protein peroxidation, heightened generation of pro-inflammatory cytokines, ultimately leading to increased apoptosis in MLE12 cells. Mechanistically, it is noteworthy that the deletion of myeloid PTEN promotes YAP translocation and regulates NRF2 expression, alleviating LPS-induced ALI via the inhibition of GSK3β and MST1 binding.

CONCLUSIONS

Our study underscores the crucial role of the myeloid PTEN-YAP-NRF2 axis in governing oxidative stress and inflammation dysregulated in ALI, indicating its potential as a therapeutic target for ALI.

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.

Kaempferol mitigates sepsis-induced acute lung injury by modulating the SphK1/S1P/S1PR1/MLC2 signaling pathway to restore the integrity of the pulmonary endothelial cell barrier

Sepsis-induced acute lung injury (SALI) is the common complication of sepsis, resulting in high incidence and mortality rates. The primary pathogenesis of SALI is the interplay between acute inflammation and endothelial barrier damage. Studies have shown that kaempferol (KPF) has anti-sepsis properties. Sphingosine kinase 1 (SphK1)/sphingosine-1-phosphate (S1P) signaling pathway's significance in acute lung damage and S1P receptor 1 (S1PR1) agonists potential in myosin light chain 2 (MLC2) phosphorylation are documented. Whether KPF can regulate the SphK1/S1P/S1PR1/MLC2 signaling pathway to protect the lung endothelial barrier remains unclear. This study investigates the KPF's therapeutic effects and molecular mechanisms in repairing endothelial cell barrier damage in both LPS-induced sepsis mice and human umbilical vein endothelial cells (HUVECs). KPF significantly reduced lung tissue damage and showed anti-inflammatory effects by decreasing IL-6 and TNF-α synthesis in the sepsis mice model. Further, KPF administration can reduce the high permeability of the LPS-induced endothelial cell barrier and alleviate lung endothelial cell barrier injury. Mechanistic studies showed that KPF pretreatment can suppress MLC2 hyperphosphorylation and decrease SphK1, S1P, and S1PR1 levels. The SphK1/S1P/S1PR1/MLC2 signaling pathway controls the downstream proteins linked to endothelial barrier damage, and the Western blot (WB) showed that KPF raised the protein levels. These proteins include zonula occludens (ZO)-1, vascular endothelial (VE)-cadherin and Occludin. The present work revealed that in mice exhibiting sepsis triggered by LPS, KPF strengthened the endothelial barrier and reduced the inflammatory response. The SphK1/S1P/S1PR1/MLC2 pathway's modulation is the mechanism underlying this impact.

HMGB1 promotes neutrophil PD-L1 expression through TLR2 and mediates T cell apoptosis leading to immunosuppression in sepsis

Neutrophils and T lymphocytes are closely related to occurrence of immunosuppression in sepsis. Studies have shown that neutrophil apoptosis decreases and T lymphocyte apoptosis increases in sepsis immunosuppression, but the specific mechanism involved remains unclear. In the present study, we found Toll-like Receptor 2 (TLR2) and programmed death-ligand 1 (PD-L1) were significantly activated in bone marrow neutrophils of wild-type mice after LPS treatment and that they were attenuated by treatment with C29, an inhibitor of TLR2. PD-L1 activation inhibits neutrophil apoptosis, whereas programmed death protein 1 (PD-1)activation promotes apoptosis of T lymphocytes, which leads to immunosuppression. Mechanistically, when sepsis occurs, pro-inflammatory factors and High mobility group box-1 protein (HMGB1) passively released from dead cells cause the up-regulation of PD-L1 through TLR2 on neutrophils. The binding of PD-L1 and PD-1 on T lymphocytes leads to increased apoptosis of T lymphocytes and immune dysfunction, eventually resulting in the occurrence of sepsis immunosuppression. In vivo experiments showed that the HMGB1 inhibitor glycyrrhizic acid (GA) and the TLR2 inhibitor C29 could inhibit the HMGB1/TLR2/PD-L1 pathway, and improving sepsis-induced lung injury. In summary, this study shows that HMGB1 regulates PD-L1 and PD-1 signaling pathways through TLR2, which leads to immunosuppression.

Knockdown of KBTBD7 attenuates septic lung injury by inhibiting ferroptosis and improving mitochondrial dysfunction

Lung injury in sepsis is caused by an excessive inflammatory response caused by the entry of pathogenic microorganisms into the body. It is also accompanied by the production of large amounts of ROS. Ferroptosis and mitochondrial dysfunction have also been shown to be related to sepsis. Finding suitable sepsis therapeutic targets is crucial for sepsis research. BTB domain-containing protein 7 (KBTBD7) is involved in regulating inflammatory responses, but its role and mechanism in the treatment of septic lung injury are still unclear. In this study, we evaluated the role and related mechanisms of KBTBD7 in septic lung injury. In in vitro studies, we established an in vitro model by inducing human alveolar epithelial cells with lipopolysaccharide (LPS) and found that KBTBD7 was highly expressed in the in vitro model. KBTBD7 knockdown could reduce the inflammatory response by inhibiting the secretion of pro-inflammatory factors and inhibit the production of ROS, ferroptosis and mitochondrial dysfunction. Mechanistic studies show that KBTBD7 interacts with FOXA1, promotes FOXA1 expression, and indirectly inhibits SLC7A11 transcription. In vivo studies have shown that knocking down KBTBD7 improves lung tissue damage in septic lung injury mice, inhibits inflammatory factors, ROS production and ferroptosis. Taken together, knockdown of KBTBD7 shows an alleviating effect on septic lung injury in vitro and in vivo, providing a potential therapeutic target for the treatment of septic lung injury.

Role of SPRY4 in health and disease

SPRY4 is a protein encoding gene that belongs to the Spry family. It inhibits the mitogen-activated protein kinase (MAPK) signaling pathway and plays a role in various biological functions under normal and pathological conditions. The SPRY4 protein has a specific structure and interacts with other molecules to regulate cellular behavior. It serves as a negative feedback inhibitor of the receptor protein tyrosine kinases (RTK) signaling pathway and interferes with cell proliferation and migration. SPRY4 also influences inflammation, oxidative stress, and cell apoptosis. In different types of tumors, SPRY4 can act as a tumor suppressor or an oncogene. Its dysregulation is associated with the development and progression of various cancers, including colorectal cancer, glioblastoma, hepatocellular carcinoma, perihilar cholangiocarcinoma, gastric cancer, breast cancer, and lung cancer. SPRY4 is also involved in organ development and is associated with ischemic diseases. Further research is ongoing to understand the expression and function of SPRY4 in specific tumor microenvironments and its potential as a therapeutic target.

Identification and Analysis of PANoptosis-Related Genes in Sepsis-Induced Lung Injury by Bioinformatics and Experimental Verification

Purpose

Sepsis-induced lung injury (SLI) is a serious complication of sepsis. PANoptosis, a novel form of inflammatory programmed cell death that is not yet to be fully investigated in SLI. Our research aims to screen and validate the signature genes of PANoptosis in SLI by bioinformatics and in vivo experiment.

Methods

SLI-related datasets were downloaded from NCBI Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) of SLI were identified and intersected with the PANoptosis gene set to obtain DEGs related to PANoptosis (SPAN_DEGs). Then, Protein-Protein Interaction (PPI) network and functional enrichment analysis were conducted based on SPAN_DEGs. SVM-REF, LASSO and RandomForest three algorithms were combined to identify the signature genes. The Nomogram and ROC curves were performed to predict diagnostic value. Immune infiltration analysis, correlation analysis and differential expression analysis were used to explore the immunological characterization, correlation and expression levels of the signature genes. Finally, H&E staining and qRT-PCR were conducted for further verification in vivo experiment.

Results

Twenty-four SPAN_DEGs were identified by intersecting 675 DEGs with the 277 PANoptosis genes. Four signature genes (CD14, GSDMD, IL1β, and FAS) were identified by three machine learning algorithms, which were highly expressed in the SLI group, and had high diagnostic value in the diagnostic model. Moreover, immune infiltration analysis showed that most immune cells and immune-related functions were higher in the SLI group than those in the control group and were closely associated with the signature genes. Finally, it was confirmed that the cecum ligation and puncture (CLP) group mice showed significant pathological damage in lung tissues, and the mRNA expression levels of CD14, IL1β, and FAS were significantly higher than the sham group.

Conclusion

CD14, FAS, and IL1β may be the signature genes in PANoptosis to drive the progression of SLI and involved in regulating immune processes.

CHRONIC CRITICAL ILLNESS-INDUCED MUSCLE ATROPHY: INSIGHTS FROM A TRAUMA MOUSE MODEL AND POTENTIAL MECHANISM MEDIATED VIA SERUM AMYLOID A

ABSTRACT

Background: Chronic critical illness (CCI), which was characterized by persistent inflammation, immunosuppression, and catabolism syndrome (PICS), often leads to muscle atrophy. Serum amyloid A (SAA), a protein upregulated in critical illness myopathy, may play a crucial role in these processes. However, the effects of SAA on muscle atrophy in PICS require further investigation. This study aims to develop a mouse model of PICS combined with bone trauma to investigate the mechanisms underlying muscle weakness, with a focus on SAA. Methods: Mice were used to examine the effects of PICS after bone trauma on immune response, muscle atrophy, and bone healing. The mice were divided into two groups: a bone trauma group and a bone trauma with cecal ligation and puncture group. Tibia fracture surgery was performed on all mice, and PICS was induced through cecal ligation and puncture surgery in the PICS group. Various assessments were conducted, including weight change analysis, cytokine analysis, hematological analysis, grip strength analysis, histochemical staining, and immunofluorescence staining for SAA. In vitro experiments using C2C12 cells (myoblasts) were also conducted to investigate the role of SAA in muscle atrophy. The effects of inhibiting receptor for advanced glycation endproducts (RAGE) or JAK2 on SAA-induced muscle atrophy were examined. Bioinformatic analysis was conducted using a dataset from the GEO database to identify differentially expressed genes and construct a coexpression network. Results: Bioinformatic analysis confirmed that SAA was significantly upregulated in muscle tissue of patients with intensive care unit-induced muscle atrophy. The PICS animal models exhibited significant weight loss, spleen enlargement, elevated levels of proinflammatory cytokines, and altered hematological profiles. Evaluation of muscle atrophy in the animal models demonstrated decreased muscle mass, grip strength loss, decreased diameter of muscle fibers, and significantly increased expression of SAA. In vitro experiment demonstrated that SAA decreased myotube formation, reduced myotube diameter, and increased the expression of muscle atrophy-related genes. Furthermore, SAA expression was associated with activation of the FOXO signaling pathway, and inhibition of RAGE or JAK2/STAT3-FOXO signaling partially reversed SAA-induced muscle atrophy. Conclusions: This study successfully develops a mouse model that mimics PICS in CCI patients with bone trauma. Serum amyloid A plays a crucial role in muscle atrophy through the JAK2/STAT3-FOXO signaling pathway, and targeting RAGE or JAK2 may hold therapeutic potential in mitigating SAA-induced muscle atrophy.

CTRP13 alleviates palmitic acid-induced inflammation, oxidative stress, apoptosis and endothelial cell dysfunction in HUVECs

C1q/tumor necrosis factor-related protein 13 (CTRP13) has been reported to participate in cardiovascular diseases. However, the role and molecular mechanism of CTRP13 in obesity-induced endothelial cell damage is still unclear. In palmitic acid (PA)-induced human umbilical vein endothelial cells (HUVECs), qRT-PCR and western blot were used to examine CTRP13 expression. CCK-8 and TUNEL assays were adopted to assess cell viability and apoptosis, respectively. ROS level and MDA content were evaluated by their commercial kits and inflammatory cytokines were measured using ELISA. Endothelial cell dysfunction was evaluated by detecting NO production and eNOS expression, and tube formation assay was performed to assess angiogenesis. AMPK pathway-related proteins were detected by western blot. The results showed that CTRP13 was downregulated in PA-induced HUVECs. CTRP13 overexpression reduced PA-induced cell viability loss and oxidative stress in HUVECs. Moreover, CTRP13 overexpression suppressed PA-induced inflammation and apoptosis, improved angiogenesis ability, and alleviated endothelial cell dysfunction in HUVECs. In addition, CTRP13 overexpression activated AMPK pathway and regulated the expressions of downstream NOX1/p38 and KLF2. Furthermore, compound C countervailed the impacts of CTRP13 overexpression on cell viability, oxidative stress, inflammation, apoptosis and endothelial function in PA-induced HUVECs. To sum up, CTRP13 overexpression may alleviate PA-induced endothelial cell damage.

Xuanbai Chengqi Decoction alleviates acute lung injury by inhibiting NLRP3 inflammasome

ETHNOPHARMACOLOGICAL RELEVANCE

Acute lung injury/acute respiratory distress syndrome (ALI/ARDS) is a prevalent critical respiratory disorder caused mostly by infection and other factors. However, effective drug therapies are currently lacking. Xuanbai Chengqi Decoction (XCD), a traditional Chinese medicine (TCM) prescription, is commonly employed to treat lung diseases. It has been recommended by Chinese health authorities as one of the TCM prescriptions for COVID-19. Nonetheless, its underlying mechanism for the treatment of ALI has not been fully understood.

AIM OF THE STUDY

The study aims to investigate the therapeutic effect of XCD on lipopolysaccharide (LPS) -induced ALI in mice and explore its anti-inflammatory mechanism involving pyroptosis.

MATERIALS AND METHODS

Ultra-performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS) was employed to identify the active compounds of XCD, and quantitative analysis of the main compounds was conducted. Male C57BL/6J mice were given different doses of XCD (4.5 and 9.0 g/kg/day) or dexamethasone (5 mg/kg/day) by oral gavage for 5 consecutive days. Subsequently, ALI was induced by injecting LPS (20 mg/kg) intraperitoneally 2 h after the last administration, and serum and lung tissues were collected 8 h later. J774A.1 cells were pretreated with different doses of XCD (100, 200, 400 μg/ml) for 12 h, then incubated with LPS (1 μg/ml) for 4 h and ATP (1 mM) for 2 h to induce pyroptosis. Supernatant and cells were collected. Moreover, J774A.1 cells were transfected with an NLRP3 overexpression plasmid for 24 h, followed by subsequent experiments with XCD (400 μg/ml). Lung histopathological changes were evaluated using hematoxylin and eosin (HE) staining. To assess the efficacy of XCD on ALI/ARDS, the levels of inflammatory factors, chemokines, and proteins associated with NLRP3 inflammasome signaling pathway were evaluated.

RESULTS

XCD was found to ameliorate lung inflammation injury in ALI mice, and reduce the protein expression of TNF-α, IL-1β, and IL-6 in both mouse serum and J774A.1 cell supernatant. Meanwhile, XCD significantly decreased the mRNA levels of IL-1β, pro-IL-1β, CXCL1, CXCL10, TNF-α, NLRP3, NF-κB P65, and the protein expression of NLRP3, Cleaved-Caspase1, and GSDMD-N in the lung and J774A.1 cells. These effects were consistent with the NLRP3 inhibitor MCC950. Furthermore, overexpression of NLRP3 reversed the anti-inflammatory effect of XCD.

CONCLUSION

The therapeutic mechanism of XCD in ALI treatment may involve alleviating inflammatory responses in lung tissues by inhibiting the activation of the NLRP3 inflammasome-mediated pyroptosis in macrophages.

Tangeretin attenuates acute lung injury in septic mice by inhibiting ROS-mediated NLRP3 inflammasome activation via regulating PLK1/AMPK/DRP1 signaling axis

OBJECTIVE

NLRP3 inflammasome-mediated pyroptosis of macrophage acts essential roles in the progression of sepsis-induced acute lung injury (ALI). Tangeretin (TAN), enriched in citrus fruit peel, presents anti-oxidative and anti-inflammatory effects. Here, we aimed to explore the potentially protective effect of TAN on sepsis-induced ALI, and the underlying mechanism of TAN in regulating NLRP3 inflammasome.

MATERIAL AND METHODS

The effect of TAN on sepsis-induced ALI and NLRP3 inflammasome-mediated pyroptosis of macrophage were examined in vivo and in vitro using a LPS-treated mice model and LPS-induced murine macrophages, respectively. The mechanism of TAN regulating the activation of NLRP3 inflammasome in sepsis-induced ALI was investigated with HE staining, Masson staining, immunofluorescent staining, ELISA, molecular docking, transmission electron microscope detection, qRT-PCR, and western blot.

RESULTS

TAN could evidently attenuate sepsis-induced ALI in mice, evidenced by reducing pulmonary edema, pulmonary congestion and lung interstitial fibrosis, and inhibiting macrophage infiltration in the lung tissue. Besides, TAN significantly suppressed inflammatory cytokine IL-1β and IL-18 expression in the serum or bronchoalveolar lavage fluid (BALF) samples of mice with LPS-induced ALI, and inhibited NLRP3 inflammasome-mediated pyroptosis of macrophages. Furthermore, we found TAN inhibited ROS production, preserved mitochondrial morphology, and alleviated excessive mitochondrial fission in LPS-induced ALI in mice. Through bioinformatic analysis and molecular docking, Polo-like kinase 1 (PLK1) was identified as a potential target of TAN for treating sepsis-induced ALI. Moreover, TAN significantly inhibited the reduction of PLK1 expression, AMP-activated protein kinase (AMPK) phosphorylation, and Dynamin related protein 1 (Drp1) phosphorylation (S637) in LPS-induced ALI in mice. In addition, Volasertib, a specific inhibitor of PLK1, abolished the protective effects of TAN against NLRP3 inflammasome-mediated pyroptosis of macrophage and lung injury in the cell and mice septic models.

CONCLUSION

TAN attenuates sepsis-induced ALI by inhibiting ROS-mediated NLRP3 inflammasome activation via regulating PLK1/AMPK/DRP1 signaling axis, and TAN is a potentially therapeutic candidate against ALI through inhibiting pyroptosis.

Network Pharmacology and Experimental Validation of the Anti-Inflammatory Effect of Tingli Dazao Xiefei Decoction in Acute Lung Injury Treatment

Purpose

Tingli Dazao Xiefei Decoction (TDXD) is a Traditional Chinese Medicine (TCM) formula used to treat acute lung injury (ALI). However, the precise mechanism of TDXD in treating ALI remains unclear. We investigated the therapeutic mechanism of TDXD against ALI using a complementary approach combining network pharmacology, molecular docking, and in vitro and in vivo experiments.

Material and Methods

Potential drug targets of TDXD and relevant target genes associated with ALI were retrieved from Chinese medicines and disease genes databases. Bioinformatics technology was employed to screen potential active ingredients and core targets. Validation experiments were conducted using a lipopolysaccharide (LPS)-induced ALI mouse (C57BL/6J) model, LPS-induced inflammatory RAW264.7 cells, and molecular docking between active compounds of TDXD and potential targets.

Results

Network pharmacology suggested that the mechanism of TDXD against ALI involved phosphoinositide 3-kinase (PI3K) / protein kinase B (AKT) / phosphatase and tensin homolog (PTEN) and Janus kinase 2 (JAK2) / signal transducer and activator of transcription 3 (STAT3) pathways. Quercetin, β-sitosterol, kaempferol, isorhamnetin, and L-stepholidine were identified as the main active compounds of TDXD that exerted anti-ALI effects. Molecular docking indicated that these compounds exhibited good binding capabilities (≤ -5kcal/mol) to key targets in PI3K/AKT/PTEN and JAK2/STAT3 signaling pathways. In the animal model, TDXD alleviated injuries and inflammatory responses in lung tissues, accompanied by inhibition of expression of tumor necrosis factor-α (TNF-α), Interleukin-6 (IL-6), STAT3, and Suppressor of Cytokine Signaling 3 (SOCS3) mRNA, and key proteins in PI3K/AKT/PTEN and JAK2/STAT3 pathways (all P values < 0.05). Cell based experiments showed that TDXD dose-dependently inhibited the expression of essential proteins in PI3K/AKT/PTEN and JAK2/STAT3 pathways (P < 0.05).

Conclusion

This study revealed that the mechanism of TDXD in ALI treatment might involve simultaneous regulation of PI3K/AKT/PTEN and JAK2/STAT3 pathways.

Sirtuin1 Mediates the Protective Effects of Echinacoside against Sepsis-Induced Acute Lung Injury via Regulating the NOX4-Nrf2 Axis

Currently, the treatment for sepsis-induced acute lung injury mainly involves mechanical ventilation with limited use of drugs, highlighting the urgent need for new therapeutic options. As a pivotal aspect of acute lung injury, the pathologic activation and apoptosis of endothelial cells related to oxidative stress play a crucial role in disease progression, with NOX4 and Nrf2 being important targets in regulating ROS production and clearance. Echinacoside, extracted from the traditional Chinese herbal plant Cistanche deserticola, possesses diverse biological activities. However, its role in sepsis-induced acute lung injury remains unexplored. Moreover, although some studies have demonstrated the regulation of NOX4 expression by SIRT1, the specific mechanisms are yet to be elucidated. Therefore, this study aimed to investigate the effects of echinacoside on sepsis-induced acute lung injury and oxidative stress in mice and to explore the intricate regulatory mechanism of SIRT1 on NOX4. We found that echinacoside inhibited sepsis-induced acute lung injury and oxidative stress while preserving endothelial function. In vitro experiments demonstrated that echinacoside activated SIRT1 and promoted its expression. The activated SIRT1 was competitively bound to p22 phox, inhibiting the activation of NOX4 and facilitating the ubiquitination and degradation of NOX4. Additionally, SIRT1 deacetylated Nrf2, promoting the downstream expression of antioxidant enzymes, thus enhancing the NOX4-Nrf2 axis and mitigating oxidative stress-induced endothelial cell pathologic activation and mitochondrial pathway apoptosis. The SIRT1-mediated anti-inflammatory and antioxidant effects of echinacoside were validated in vivo. Consequently, the SIRT1-regulated NOX4-Nrf2 axis may represent a crucial target for echinacoside in the treatment of sepsis-induced acute lung injury.

Self-Propelled Proteomotors with Active Cell-Free mtDNA Clearance for Enhanced Therapy of Sepsis-Associated Acute Lung Injury

Acute lung injury (ALI) is a frequent and serious complication of sepsis with limited therapeutic options. Gaining insights into the inflammatory dysregulation that causes sepsis-associated ALI can help develop new therapeutic strategies. Herein, the crucial role of cell-free mitochondrial DNA (cf-mtDNA) in the regulation of alveolar macrophage activation during sepsis-associated ALI is identified. Most importantly, a biocompatible hybrid protein nanomotor (NM) composed of recombinant deoxyribonuclease I (DNase-I) and human serum albumin (HSA) via glutaraldehyde-mediated crosslinking is prepared to obtain an inhalable nanotherapeutic platform targeting pulmonary cf-mtDNA clearance. The synthesized DNase-I/HSA NMs are endowed with self-propulsive capability and demonstrate superior performances in stability, DNA hydrolysis, and biosafety. Pulmonary delivery of DNase-I/HSA NMs effectively eliminates cf-mtDNAs in the lungs, and also improves sepsis survival by attenuating pulmonary inflammation and lung injury. Therefore, pulmonary cf-mtDNA clearance strategy using DNase-I/HSA NMs is considered to be an attractive approach for sepsis-associated ALI.

Mitochondrial DNA Variations Modulate Alveolar Epithelial Mitochondrial Function and Oxidative Stress in Newborn Mice Exposed to Hyperoxia

Oxidative stress is an important contributor to bronchopulmonary dysplasia (BPD), a form of chronic lung disease that is the most common morbidity in very preterm infants. Mitochondrial functional differences due to inherited and acquired mutations influence the pathogenesis of disorders in which oxidative stress plays a critical role. We previously showed using mitochondrial-nuclear exchange (MNX) mice that mitochondrial DNA (mtDNA) variations modulate hyperoxia-induced lung injury severity in a model of BPD. In this study, we studied the effects of mtDNA variations on mitochondrial function including mitophagy in alveolar epithelial cells (AT2) from MNX mice. We also investigated oxidant and inflammatory stress as well as transcriptomic profiles in lung tissue in mice and expression of proteins such as PINK1, Parkin and SIRT3 in infants with BPD. Our results indicate that AT2 from mice with C57 mtDNA had decreased mitochondrial bioenergetic function and inner membrane potential, increased mitochondrial membrane permeability and were exposed to higher levels of oxidant stress during hyperoxia compared to AT2 from mice with C3H mtDNA. Lungs from hyperoxia-exposed mice with C57 mtDNA also had higher levels of pro-inflammatory cytokines compared to lungs from mice with C3H mtDNA. We also noted changes in KEGG pathways related to inflammation, PPAR and glutamatergic signaling, and mitophagy in mice with certain mito-nuclear combinations but not others. Mitophagy was decreased by hyperoxia in all mice strains, but to a greater degree in AT2 and neonatal mice lung fibroblasts from hyperoxia-exposed mice with C57 mtDNA compared to C3H mtDNA. Finally, mtDNA haplogroups vary with ethnicity, and Black infants with BPD had lower levels of PINK1, Parkin and SIRT3 expression in HUVEC at birth and tracheal aspirates at 28 days of life when compared to White infants with BPD. These results indicate that predisposition to neonatal lung injury may be modulated by variations in mtDNA and mito-nuclear interactions need to be investigated to discover novel pathogenic mechanisms for BPD.

miR-125b-5p in adipose derived stem cells exosome alleviates pulmonary microvascular endothelial cells ferroptosis via Keap1/Nrf2/GPX4 in sepsis lung injury

BACKGROUND

Sepsis is a fatal disease with a high rate of morbidity and mortality, during which acute lung injury is the earliest and most serious complication. Injury of pulmonary microvascular endothelial cells (PMVECs) induced by excessive inflammation plays an important role in sepsis acute lung injury. This study is meant to explore the protective effect and mechanism of ADSCs exosomes on excessive inflammation PMVECs injury.

RESULTS

We successfully isolated ADSCs exosomes, the characteristic of which were confirmed. ADSCs exosomes reduced excessive inflammatory response induced ROS accumulation and cell injury in PMVECs. Besides, ADSCs exosomes inhibited excessive inflammatory response induced ferroptosis while upregulated expression of GPX4 in PMVECs. And further GPX4 inhibition experiments revealed that ADSCs exosomes alleviated inflammatory response induced ferroptosis via upregulating GPX4. Meanwhile, ADSCs exosomes could increase the expression and nucleus translocation of Nrf2, while decrease the expression of Keap1. miRNA analysis and further inhibition experiments verified that specific delivery of miR-125b-5p by ADSCs exosomes inhibited Keap1 and alleviated ferroptosis. In CLP induced sepsis model, ADSCs exosomes could relieve the lung tissue injury and reduced the death rate. Besides, ADSCs exosomes alleviated oxidative stress injury and ferroptosis of lung tissue, while remarkably increase expression of Nrf2 and GPX4.

CONCLUSION

Collectively, we illustrated a novel potentially therapeutic mechanism that miR-125b-5p in ADSCs exosomes could alleviate the inflammation induced PMVECs ferroptosis in sepsis induced acute lung injury via regulating Keap1/Nrf2/GPX4 expression, hence improve the acute lung injury in sepsis.