Buformin alleviates sepsis-induced acute lung injury via inhibiting NLRP3-mediated pyroptosis through an AMPK-dependent pathway

Bay-117082 treats sepsis by inhibiting neutrophil extracellular traps (NETs) formation through down-regulating NLRP3/N-GSDMD

During the inflammatory storm of sepsis, a significant quantity of neutrophil extracellular traps (NETs) are generated, which act as a double-edged sword and not only impede the invasion of foreign microorganisms but also exacerbate organ damage. This study provides evidence that NETs can cause damage to alveolar epithelial cells in vitro. The sepsis model developed in this study showed a significant increase in NETs in the bronchoalveolar lavage fluid (BALF). The development of NETs has been shown to increase the lung inflammatory response and aggravate injury to alveolar epithelial cells. Bay-117082, a well-known NF-κB suppressor, is used to modulate inflammation. This analysis revealed that Bay-117082 efficiently reduced total protein concentration, myeloperoxidase activity, and inflammatory cytokines in BALF. Moreover, Bay-117082 inhibited the formation of NETs, which in turn prevented the activation of the pore-forming protein gasdermin D (GSDMD). In summary, these results indicated that excessive NET production during sepsis exacerbated the onset and progression of acute lung injury (ALI). Therefore, Bay-117082 could serve as a novel therapeutic approach for ameliorating sepsis-associated ALI.

Autophagy modulation in cancer therapy: Challenges coexist with opportunities

Autophagy, a crucial intracellular degradation process facilitated by lysosomes, plays a pivotal role in maintaining cellular homeostasis. The elucidation of autophagy key genes and signaling pathways has significantly advanced our understanding of this process and has led to the exploration of autophagy as a promising therapeutic approach. This review comprehensively assesses the latest developments in small molecule modulators targeting autophagy. Moreover, the review delves into the most recent strategies for drug discovery, specifically focusing on selective agents that exploit autophagosomes and lysosomes for targeted protein degradation. Additionally, this article highlights the prevailing challenges and outlines potential future advancements in the field. By amalgamating the cutting-edge knowledge in the field, we aim to offer valuable insights and references for the anti-cancer drug development of autophagy-targeted therapies, thus contributing to the advancement of novel therapeutic interventions.

Activation of the AMPK/Nrf2 pathway ameliorates LPS-induced acute lung injury by inhibiting oxidative stress and reducing inflammation

BACKGROUND

Numerous diseases-related acute lung injury (ALI) contributed to high mortality. Currently, the therapeutic effect of ALI was still poor. The detailed mechanism of ALI remained elusive and this study aimed to elucidate the mechanism of ALI.

METHOD

This study was performed to expose the molecular mechanisms of AMPK/Nrf2 pathway regulating oxidative stress in LPS-induced AMI mice. The mouse ALI model was established via intraperitoneal injection of LPS, then the lung tissue and blood samples were obtained, followed by injection with Dimethyl fumarate (DMF). Finally, Western blot, HE staining, injury score, lung wet/dry ratio, reactive oxygen species (ROS) and ELISA were used to elucidate the mechanism of AMPK/Nrf2 pathway in LPS -induced acute lung injury by mediating oxidative stress.

RESULTS

The lung tissue injury score was evaluated, showing higher scores in the model group compared to the AMPK activator and control groups. DCFH-DA indicated that LPS increased ROS production, while AMPK activator DMF reduced it, with the model group exhibiting higher ROS levels than the control and AMPK activator groups. The lung wet/dry ratio was also higher in the model group. Western blot analysis revealed LPS reduced AMPK and Nrf2 protein levels, but DMF reversed this effect. ELISA results showed elevated IL-6 and IL-1β levels in the model group compared to the AMPK activator and control groups.

CONCLUSION

CONCLUSION: Activating the AMPK/Nrf2 pathway can improve LPS-induced acute lung injury by down-regulation of the oxidative stress and corresponding inflammatory factor level.

Pyroptosis in health and disease: mechanisms, regulation and clinical perspective

Pyroptosis is a type of programmed cell death characterized by cell swelling and osmotic lysis, resulting in cytomembrane rupture and release of immunostimulatory components, which play a role in several pathological processes. Significant cellular responses to various stimuli involve the formation of inflammasomes, maturation of inflammatory caspases, and caspase-mediated cleavage of gasdermin. The function of pyroptosis in disease is complex but not a simple angelic or demonic role. While inflammatory diseases such as sepsis are associated with uncontrollable pyroptosis, the potent immune response induced by pyroptosis can be exploited as a therapeutic target for anti-tumor therapy. Thus, a comprehensive review of the role of pyroptosis in disease is crucial for further research and clinical translation from bench to bedside. In this review, we summarize the recent advancements in understanding the role of pyroptosis in disease, covering the related development history, molecular mechanisms including canonical, non-canonical, caspase 3/8, and granzyme-mediated pathways, and its regulatory function in health and multiple diseases. Moreover, this review also provides updates on promising therapeutic strategies by applying novel small molecule inhibitors and traditional medicines to regulate pyroptosis. The present dilemmas and future directions in the landscape of pyroptosis are also discussed from a clinical perspective, providing clues for scientists to develop novel drugs targeting pyroptosis.

CircMAPK1 induces cell pyroptosis in sepsis-induced lung injury by mediating KDM2B mRNA decay to epigenetically regulate WNK1

BACKGROUND

Macrophage pyroptosis is a pivotal inflammatory mechanism in sepsis-induced lung injury, however, the underlying mechanisms remain inadequately elucidated.

METHODS

Lipopolysaccharides (LPS)/adenosine triphosphate (ATP)-stimulated macrophages and cecal ligation and puncture (CLP)-induced mouse model for sepsis were established. The levels of key molecules were examined by qRT-PCR, Western blotting, immunohistochemistry (IHC) and ELISA assay. The subcellular localization of circMAPK1 was detected by RNA fluorescence in situ hybridization (FISH). Cell viability, LDH release and caspase-1 activity were monitored by CCK-8, LDH assays, and flow cytometry. The bindings between KDM2B/H3K36me2 and WNK1 promoter was detected by chromatin immunoprecipitation (ChIP) assay and luciferase assay, and associations among circMAPK1, UPF1 and KDM2B mRNA were assessed by RNA pull-down or RNA immunoprecipitation (RIP) assays. The pathological injury of lung tissues was evaluated by lung wet/dry weight ratio and hematoxylin and eosin (H&E) staining.

RESULTS

CircMAPK1 was elevated in patients with septic lung injury. Knockdown of circMAPK1 protected against LPS/ATP-impaired cell viability and macrophage pyroptosis via WNK1/NLRP3 axis. Mechanistically, loss of circMAPK1 enhanced the association between KDM2B and WNK1 promoter to promote the demethylation of WNK1 and increase its expression. CircMAPK1 facilitated KDM2B mRNA decay by recruiting UPF1. Functional experiments showed that silencing of KDM2B or WNK1 counteracted circMAPK1 knockdown-suppressed macrophage pyroptosis. In addition, silencing of circMAPK1 alleviated CLP-induced lung injury in mice via KDM2B/WNK1/NLRP3 axis.

CONCLUSION

CircMAPK1 exacerbates sepsis-induced lung injury by destabilizing KDM2B mRNA to suppress WNK1 expression, thus facilitating NLRP3-driven macrophage pyroptosis.

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.

Anisodamine hydrobromide ameliorates acute lung injury via inhibiting pyroptosis in murine sepsis model

OBJECTIVE

Sepsis can have severe implications on lung function, leading to acute lung injury (ALI), a major contributor to sepsis-related mortality. Anisodamine hydrobromide (Ani HBr), a bioactive constituent derived from the root of Scopolia tangutica Maxim, a plant endemic to China, has demonstrated efficacy in treating septic shock. We aim to explore whether Ani HBr can alleviate sepsis-triggered ALI and elucidate the fundamental mechanisms involved.

MATERIALS AND METHOD

The protective effects of Ani HBr were assessed in two models: in vitro, lipopolysaccharide (LPS)-stimulated RAW264.7 cells, and in vivo, cecal ligation puncture (CLP)-induced sepsis. To measure the cell viability of RAW264.7 cells after Ani HBr treatment, we used the CCK-8 assay. We quantified the levels of pro-inflammatory cytokines expression using ELISA. We also measured the expression of pyrotosis indicators by quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR), Western blotting, and immunofluorescence.

RESULTS

Our study demonstrates that Ani HBr can alleviate pulmonary edema, bleeding, and excessive inflammation induced by CLP. Additionally, it exhibits protective effects against cytotoxicity induced by LPS in RAW264.7 macrophage cells. Furthermore, Ani HBr downregulates the mRNA and protein levels of NLRP3, Caspase-1, GSDMD, IL-18, and IL-1β in both animal models and cell cultures, thereby inhibiting pyroptosis in a similar mechanism to AC-YVAD-CMK (AYC)'s blockade of Caspase-1. Moreover, Ani HBr suppresses the production and release of proinflammatory cytokines.

CONCLUSION

These findings suggest that Ani HBr could serve as a protective agent against sepsis-induced ALI by suppressing pyroptosis.

Abscisic acid for acute respiratory distress syndrome therapy by suppressing alveolar macrophage pyroptosis via upregulating acyloxyacyl hydrolase expression

OBJECTIVE

Abscisic acid (ABA) is a phytohormone that inhibits airway inflammation in acute respiratory distress syndrome (ARDS) mouse models. However, the molecular mechanism underlying this phenomenon remains unclear.

METHODS

Serum ABA level in patients and mice was measured via liquid chromatography-tandem mass spectrometry (LC-MS/MS). In-depth molecular mechanism was investigated through transmission electron microscopy, RNA-sequencing, and molecular docking in ARDS mice and cultured primary alveolar macrophages (AMs).

RESULTS

We found that the serum ABA level was remarkably decreased in ARDS mice and patients. ABA inhibited lipopolysaccharide (LPS)-induced airway inflammation in mice; moreover, it downregulated genes associated with pyroptosis, as shown by RNA-sequencing and lung protein immunoblots. ABA inhibited the formation of membrane pores in AMs and suppressed the cleavage of gasdermin D (GSDMD) and the activation of caspase-11 and caspase-1 in vivo and in vitro; however, the overexpression of caspase-11 reversed the protective effect of ABA on LPS-induced pyroptosis of primary AMs. ABA inhibited intra-AM LPS accumulation while increasing the level of acyloxyacyl hydrolase (AOAH) in AMs, whereas AOAH deficiency abrogated the suppressive action of ABA on inflammation, pyroptosis, and intra-AM LPS accumulation in vivo and in vitro. Importantly, ABA promoted its intracellular receptor lanthionine C-like receptor 2 interacting with transcription factor peroxisome proliferator-activated receptor γ, which ultimately leading to increase AOAH expression to inactivate LPS and inhibit pyroptosis in AMs.

CONCLUSIONS

ABA protected against LPS-induced lung injury by inhibiting pyroptosis in AMs via proliferator-activated receptor γ-mediated AOAH expression.

Role and mechanisms of autophagy, ferroptosis, and pyroptosis in sepsis-induced acute lung injury

Sepsis-induced acute lung injury (ALI) is a major cause of death among patients with sepsis in intensive care units. By analyzing a model of sepsis-induced ALI using lipopolysaccharide (LPS) and cecal ligation and puncture (CLP), treatment methods and strategies to protect against ALI were discussed, which could provide an experimental basis for the clinical treatment of sepsis-induced ALI. Recent studies have found that an imbalance in autophagy, ferroptosis, and pyroptosis is a key mechanism that triggers sepsis-induced ALI, and regulating these death mechanisms can improve lung injuries caused by LPS or CLP. This article summarized and reviewed the mechanisms and regulatory networks of autophagy, ferroptosis, and pyroptosis and their important roles in the process of LPS/CLP-induced ALI in sepsis, discusses the possible targeted drugs of the above mechanisms and their effects, describes their dilemma and prospects, and provides new perspectives for the future treatment of sepsis-induced ALI.

Qi Huang Fang improves intestinal barrier function and intestinal microbes in septic mice through NLRP3 inflammasome-mediated cellular pyroptosis

OBJECTIVE

Sepsis has a high incidence, morbidity, and mortality rate and is a great threat to human safety. Gut health plays an important role in sepsis development. Qi Huang Fang (QHF) contains astragalus, rhubarb, zhishi, and atractylodes. It is used to treat syndromes of obstructive qi and deficiency of righteousness. This study aimed to investigate whether QHF improves intestinal barrier function and microorganisms in mice through NLRP3 inflammatory vesicle-mediated cellular focal death.

METHODS

A mouse model of sepsis was constructed by cecal ligation and puncture (CLP) of specific pathogen-free (SPF)-grade C57BL/6 mice after continuous gavage of low, medium, and high doses of astragalus formula or probiotics for 4 weeks. Twenty-four hours postoperatively, the mechanism of action of QHF in alleviating septic intestinal dysfunction and restoring intestinal microecology, thereby alleviating intestinal injury, was evaluated by pathological observation, immunohistochemistry, western blotting, ELISA, and 16S rDNA high-throughput sequencing.

RESULTS

Different doses of QHF and probiotics ameliorated intestinal injury and reduced colonic apoptosis in mice to varying degrees (P < 0.05). Meanwhile, different doses of QHF and probiotics were able to reduce the serum levels of IL-6, IL-1β, and TNF-α (P < 0.05); down-regulate the protein expression of NLRP3, caspase-1, and caspase-11 (P < 0.05); and up-regulate the protein expression of zonula occluden-1 (ZO-1) and occludin (P < 0.05), which improved the intestinal barrier function in mice. In addition, QHF decreased the relative abundance of harmful bacteria (Firmicutes, Muribaculaceae, Campilobacterota, Helicobacter, and Alistipes) and increased the relative abundance of beneficial bacteria (Bacteroidetes and Actinobacteria) (P < 0.05).

CONCLUSION

QHF improves intestinal barrier function and gut microbiology in mice via NLRP3 inflammasome-mediated cellular pyroptosis.

Targeting the AMPK/Nrf2 Pathway: A Novel Therapeutic Approach for Acute Lung Injury

ALI(acute lung injury) is a severe respiratory dysfunction caused by various intrapulmonary and extrapulmonary factors. It is primarily characterized by oxidative stress and affects the integrity of the pulmonary barrier. In severe cases, ALI can progress to ARDS(acute respiratory distress syndrome), a condition that poses a serious threat to the lives of affected patients. To date, the etiological mechanisms underlying ALI remain elusive, and available therapeutic options are quite limited. AMPK(AMP-activated protein kinase), an essential serine/threonine protein kinase, performs a pivotal function in the regulation of cellular energy levels and cellular regulatory mechanisms, including the detection of redox signals and mitigating oxidative stress. Meanwhile, Nrf2(nuclear factor erythroid 2-related factor 2), a critical transcription factor, alleviates inflammation and oxidative responses by interacting with multiple signaling pathways and contributing to the modulation of oxidative enzymes associated with inflammation and programmed cell death. Indeed, AMPK induces the dissociation of Nrf2 from Keap1(kelch-like ECH-associated protein-1) and facilitates its translocation into the nucleus to trigger the transcription of downstream antioxidant genes, ultimately suppressing the expression of inflammatory cells in the lungs. Given their roles, AMPK and Nrf2 hold promise as novel treatment targets for ALI. This study aimed to summarise the current status of research on the AMPK/Nrf2 signaling pathway in ALI, encompassing recently reported natural compounds and drugs that can activate the AMPK/Nrf2 signaling pathway to alleviate lung injury, and provide a theoretical reference for early intervention in lung injury and future research on lung protection.

Metformin Mitigates Sepsis-Induced Acute Lung Injury and Inflammation in Young Mice by Suppressing the S100A8/A9-NLRP3-IL-1β Signaling Pathway

Background

Globally, the subsequent complications that accompany sepsis result in remarkable morbidity and mortality rates. The lung is among the vulnerable organs that incur the sepsis-linked inflammatory storm and frequently culminates into ARDS/ALI. The metformin-prescribed anti-diabetic drug has been revealed with anti-inflammatory effects in sepsis, but the underlying mechanisms remain unclear. This study aimed to ascertain metformin's effects and functions in a young mouse model of sepsis-induced ALI.

Methods

Mice were randomly divided into 4 groups: sham, sham+ Met, CLP, and CLP+ Met. CLP was established as the sepsis-induced ALI model accompanied by intraperitoneal metformin treatment. At day 7, the survival state of mice was noted, including survival rate, weight, and M-CASS. Lung histological pathology and injury scores were determined by hematoxylin-eosin staining. The pulmonary coefficient was used to evaluate pulmonary edema. Furthermore, IL-1β, CCL3, CXCL11, S100A8, S100A9 and NLRP3 expression in tissues collected from lungs were determined by qPCR, IL-1β, IL-18, TNF-α by ELISA, caspase-1, ASC, NLRP3, P65, p-P65, GSDMD-F, GSDMD-N, IL-1β and S100A8/A9 by Western blot.

Results

The data affirmed that metformin enhanced the survival rate, lessened lung tissue injury, and diminished the expression of inflammatory factors in young mice with sepsis induced by CLP. In contrast to sham mice, the CLP mice were affirmed to manifest ALI-linked pathologies following CLP-induced sepsis. The expressions of pro-inflammatory factors, for instance, IL-1β, IL-18, TNF-α, CXCL11, S100A8, and S100A9 are markedly enhanced by CLP, while metformin abolished this adverse effect. Western blot analyses indicated that metformin inhibited the sepsis-induced activation of GSDMD and the upregulation of S100A8/A9, NLRP3, and ASC.

Conclusion

Metformin could improve the survival rate, lessen lung tissue injury, and minimize the expression of inflammatory factors in young mice with sepsis induced by CLP. Metformin reduced sepsis-induced ALI via inhibiting the NF-κB signaling pathway and inhibiting pyroptosis by the S100A8/A9-NLRP3-IL-1β pathway.

Peficitinib alleviated acute lung injury by blocking glycolysis through JAK3/STAT3 pathway

Peficitinib is a selective Janus kinase (JAK3) inhibitor recently developed and approved for the treatment of rheumatoid arthritis in Japan. Glycolysis in macrophages could induce NOD-like receptor (NLR) family and pyrin domain-containing protein 3 (NLRP3) inflammasome activation, thus resulting in pyroptosis and acute lung injury (ALI). The aim of our study was to investigate whether Peficitinib could alleviate lipopolysaccharide (LPS)-induced ALI by inhibiting NLRP3 inflammasome activation. Wild type C57BL/6J mice were intraperitoneally injected with Peficitinib (5 or 10 mg·kg-1·day-1) for 7 consecutive days before LPS injection. The results showed that Peficitinib pretreatment significantly relieved LPS-induced pulmonary edema, inflammation, and apoptosis. NLRP3 inflammasome and glycolysis in murine lung tissues challenged with LPS were also blocked by Peficitinib. Furthermore, we found that the activation of JAK3/signal transducer and activator of transcription 3 (STAT3) was also suppressed by Peficitinib in mice with ALI. However, in Jak3 knockout mice, Peficitinib did not show obvious protective effects after LPS injection. In vitro experiments further showed that Jak3 overexpression completely abolished Peficitinib-elicited inhibitory effects on pyroptosis and glycolysis in LPS-induced RAW264.7 macrophages. Finally, we unveiled that LPS-induced activation of JAK3/STAT3 was mediated by toll-like receptor 4 (TLR4) in RAW264.7 macrophages. Collectively, our study proved that Peficitinib could protect against ALI by blocking JAK3-mediated glycolysis and pyroptosis in macrophages, which may serve as a promising candidate against ALI in the future.

Preclinical evidence using synthetic compounds and natural products indicates that AMPK represents a potential pharmacological target for the therapy of pulmonary diseases

Adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) is a highly conserved eukaryotic enzyme discovered as a key regulator of cellular energy homeostasis, with anti-inflammation, antioxidative stress, anticancer, and antifibrosis beneficial effects. AMPK is dysregulated in human pulmonary diseases such as acute lung injury, nonsmall cell lung cancer, pulmonary fibrosis, chronic obstructive pulmonary disease, and asthma. This review provides an overview of the beneficial role of natural, synthetic, and Chinese traditional medicines AMPK modulators in pulmonary diseases, and highlights the role of the AMPK signaling pathway in the lung, emphasizing the importance of finding lead compounds and drugs that can target and modulate AMPK to treat the lung diseases.

Mangiferin alleviates diabetic pulmonary fibrosis in mice via inhibiting endothelial-mesenchymal transition through AMPK/FoxO3/SIRT3 axis

Diabetes mellitus results in numerous complications. Diabetic pulmonary fibrosis (DPF), a late pulmonary complication of diabetes, has not attracted as much attention as diabetic nephropathy and cardiomyopathy. Mangiferin (MF) is a natural small molecular compound that exhibits a variety of pharmacological effects including anti-inflammatory, anti-cancer, anti-diabetes, and anti-fibrosis effects. In this study, we investigated whether long-term diabetes shock induces DPF, and explored whether MF had a protective effect against DPF. We first examined the lung tissues and sections of 20 diabetic patients obtained from discarded lung surgical resection specimens and found that pulmonary fibrosis mainly accumulated around the pulmonary vessels, accompanied by significantly enhanced endothelial-mesenchymal transition (EndMT). We established a mouse model of DPF by STZ injections. Ten days after the final STZ injection, the mice were administered MF (20, 60 mg/kg, i.g.) every 3 days for 4 weeks, and kept feeding until 16 weeks and euthanized. We showed that pulmonary fibrotic lesions were developed in the diabetic mice, which began around the pulmonary vessels, while MF administration did not affect long-term blood glucose levels, but dose-dependently alleviated diabetes-induced pulmonary fibrosis. In human umbilical vein endothelial cells (HUVECs), exposure to high glucose (33.3 mM) induced EndMT, which was dose-dependently inhibited by treatment with MF (10, 50 μM). Furthermore, MF treatment promoted SIRT3 expression in high glucose-exposed HUVECs by directly binding to AMPK to enhance the activity of FoxO3, which finally reversed diabetes-induced EndMT. We conclude that MF attenuates DPF by inhibiting EndMT through the AMPK/FoxO3/SIRT3 axis. MF could be a potential candidate for the early prevention and treatment of DPF.

ANGPTL2 knockdown induces autophagy to relieve alveolar macrophage pyroptosis by reducing LILRB2-mediated inhibition of TREM2

Acute lung injury (ALI) is featured with a robust inflammatory response. Angiopoietin-like protein 2 (ANGPTL2), a pro-inflammatory protein, is complicated with various disorders. However, the role of ANGPTL2 in ALI remains to be further explored. The mice and MH-S cells were administrated with lipopolysaccharide (LPS) to evoke the lung injury in vivo and in vitro. The role and mechanism of ANGPTL was investigated by haematoxylin-eosin, measurement of wet/dry ratio, cell count, terminal deoxynucleotidyl transferase deoxyuridine triphosphate (dUTP) nick end labeling, reverse transcription quantitative polymerase chain reaction, immunofluorescence, enzyme-linked immunosorbent assay, detection of autophagic flux and western blot assays. The level of ANGPTL2 was upregulated in lung injury. Knockout of ANGPTL2 alleviated LPS-induced pathological symptoms, reduced pulmonary wet/dry weight ratio, the numbers of total cells and neutrophils in BALF, apoptosis rate and the release of pro-inflammatory mediators, and modulated polarization of alveolar macrophages in mice. Knockdown of ANGPTL2 downregulated the level of pyroptosis indicators, and elevated the level of autophagy in LPS-induced MH-S cells. Besides, downregulation of ANGPTL2 reversed the LPS-induced the expression of leukocyte immunoglobulin (Ig)-like receptor B2 (LILRB2) and triggering receptor expressed on myeloid cells 2 (TREM2), which was reversed by the overexpression of LILRB2. Importantly, knockdown of TREM2 reversed the levels of autophagy- and pyroptosis-involved proteins, and the contents of pro-inflammatory factors in LPS-induced MH-S cells transfected with si ANGPTL2, which was further inverted with the treatment of rapamycin. Therefore, ANGPTL2 silencing enhanced autophagy to alleviate alveolar macrophage pyroptosis via reducing LILRB2-mediated inhibition of TREM2.

Songorine inhibits oxidative stress-related inflammation through PI3K/AKT/NRF2 signaling pathway to alleviate lipopolysaccharide-induced septic acute lung injury

OBJECTIVE

The present study aimed to investigate the protective action and mechanism of songorine on sepsis-induced acute lung injury (ALI).

METHODS

The sepsis-induced ALI mouse and cell models were established by lipopolysaccharide (LPS) induction. Lung injury was assayed by hematoxylin and eosin staining, lung injury score, and lung wet-to-dry (W/D) weight ratio. Apoptosis in lung tissues was evaluated by TUNEL assay, and the expression of apoptosis-related markers (Bcl2, Bax, and caspase-3) was measured by western blotting. Levels of pro-inflammatory factors and oxidative stress markers in the bronchoalveolar lavage fluid (BALF) of mice were measured by ELISA and RT-qPCR. The expression of PI3K/AKT/NRF2 pathway-related proteins was analyzed by western blotting.

RESULTS

Songorine treatment at 40 mg/kg mitigated sepsis-induced ALI, characterized by improved histopathology, lung injury score, and lung W/D weight ratio (p < 0.05). Moreover, songorine markedly attenuated sepsis-induced apoptosis in lung tissues; this was evidenced by an increase in Bcl2 levels and a decrease in Bax and caspase-3 levels (p < 0.01). Also, songorine reduced levels of proinflammatory cytokines (TNF-α, IL-6, IL-1β and MPO) and oxidative stress regulators (SOD and GSH) in the BALF of LPS-induced sepsis mice and RAW264.7 cells (p < 0.05). In addition, songorine upregulated the PI3K/AKT/NRF2 pathway-related proteins in LPS-induced sepsis mice and RAW264.7 cells (p < 0.05). Furthermore, LY294002 (a PI3K inhibitor) treatment reversed the protective effect of songorine on sepsis-induced ALI.

CONCLUSION

Songorine inhibits oxidative stress-related inflammation in sepsis-induced ALI via the activation of the PI3K/AKT/NRF2 signaling pathway.

LL-37 improves sepsis-induced acute lung injury by suppressing pyroptosis in alveolar epithelial cells

BACKGROUND

LL-37 (also known as murine CRAMP) is a human antimicrobial peptide that plays a crucial role in innate immune defence against sepsis through various mechanisms. However, its involvement in sepsis-induced lung injury remains unclear.

OBJECTIVES

This work investigates the impact of LL-37 on pyroptosis generated by LPS in alveolar epithelial cells. The research utilizes both in vivo and in vitro sepsis-associated acute lung injury (ALI) models to understand the underlying molecular pathways.

METHODS

In vivo, an acute lung injury model induced by sepsis was established by intratracheal administration of LPS in C57BL/6J mice, which were subsequently treated with low-dose CRAMP (recombinant murine cathelicidin, 2.5 mg.kg-1) and high-dose CRAMP (5.0 mg.kg-1). In vitro, pyroptosis was induced in a human alveolar epithelial cell line (A549) by stimulation with LPS and ATP. Treatment was carried out with recombinant human LL-37, or LL-37 was knocked out in A549 cells using small interfering RNA (siRNA). Subsequently, haematoxylin and eosin staining was performed to observe the histopathological changes in lung tissues in the control group and sepsis-induced lung injury group. TUNEL and PI staining were used to observe DNA fragmentation and pyroptosis in mouse lung tissues and cells in the different groups. An lactate dehydrogenase (LDH) assay was performed to measure the cell death rate. The expression levels of NLRP3, caspase1, caspase 1 p20, GSDMD, NT-GSDMD, and CRAMP were detected in mice and cells using Western blotting, qPCR, and immunohistochemistry. ELISA was used to assess the levels of interleukin (IL)-1β and IL-18 in mouse serum, bronchoalveolar lavage fluid (BALF) and lung tissue and cell culture supernatants.

RESULTS

The expression of NLRP3, caspase1 p20, NT-GSDMD, IL 18 and IL1β in the lung tissue of mice with septic lung injury was increased, which indicated activation of the canonical pyroptosis pathway and coincided with an increase in CRAMP expression. Treatment with recombinant CRAMP improved pyroptosis in mice with lung injury. In vitro, treatment with LPS and ATP upregulated these classic pyroptosis molecules, LL-37 knockdown exacerbated pyroptosis, and recombinant human LL-37 treatment alleviated pyroptosis in alveolar epithelial cells.

CONCLUSION

These findings indicate that LL-37 protects against septic lung injury by modulating the expression of classic pyroptotic pathway components, including NLRP3, caspase1, and GSDMD and downstream inflammatory factors in alveolar epithelial cells.

CGRP is essential for protection against alveolar epithelial cell necroptosis by activating the AMPK/L-OPA1 signaling pathway during acute lung injury

Alveolar epithelial cell (AEC) necroptosis is critical to disrupt the alveolar barrier and provoke acute lung injury (ALI). Here, we define calcitonin gene-related peptide (CGRP), the most abundant endogenous neuropeptide in the lung, as a novel modulator of AEC necroptosis in lipopolysaccharide (LPS)-induced ALI. Upon LPS-induced ALI, overexpression of Cgrp significantly mitigates the inflammatory response, alleviates lung tissue damage, and decreases AEC necroptosis. Similarly, CGRP alleviated AEC necroptosis under the LPS challenge in vitro. Previously, we identified that long optic atrophy 1 (L-OPA1) deficiency mediates mitochondrial fragmentation, leading to AEC necroptosis. In this study, we discovered that CGRP positively regulated mitochondrial fusion through stabilizing L-OPA1. Mechanistically, we elucidate that CGRP activates AMP-activated protein kinase (AMPK). Furthermore, the blockade of AMPK compromised the protective effect of CGRP against AEC necroptosis following the LPS challenge. Our study suggests that CRGP-mediated activation of the AMPK/L-OPA1 axis may have potent therapeutic benefits for patients with ALI or other diseases with necroptosis.

Knockdown of angiopoietin-like 4 suppresses sepsis-induced acute lung injury by blocking the NF-κB pathway activation and hindering macrophage M1 polarization and pyroptosis

OBJECTIVE

Sepsis-induced acute lung injury (ALI) is a life-threatening disease. Macrophage pyroptosis has been reported to exert function in ALI. We aimed to investigate the mechanisms of ANGPTL4-mediated cell pyroptosis in sepsis-induced ALI, thus providing new insights into the pathogenesis and prevention and treatment measures of sepsis-induced ALI.

METHODS

In vivo animal models and in vitro cell models were established by cecal ligation and puncture (CLP) method and lipopolysaccharide-induced macrophages RAW264.7. ANGPTL4 was silenced in CLP mice or macrophages, followed by the determination of ANGPTL4 expression in bronchoalveolar lavage fluid (BALF) or macrophages. Lung histopathology was observed by H&E staining, with pathological injury scores evaluated and lung wet and dry weight ratio recorded. M1/M2 macrophage marker levels (iNOS/CD86/Arg1), inflammatory factor (TNF-α/IL-6/IL-1β/iNOS) expression in BALF, cell death and pyroptosis, NLRP3 inflammasome, cell pyroptosis-related protein (NLRP3/Cleaved-caspase-1/caspase-1/GSDMD-N) levels, NF-κB pathway activation were assessed by RT-qPCR/ELISA/flow cytometry/Western blot, respectively.

RESULTS

ANGPTL4 was highly expressed in mice with sepsis-induced ALI, and ANGPTL4 silencing ameliorated sepsis-induced ALI in mice. In vivo, ANGPTL4 silencing repressed M1 macrophage polarization and macrophage pyroptosis in mice with sepsis-induced ALI. In vitro, ANGPTL4 knockout impeded LPS-induced activation and pyroptosis of M1 macrophages and hindered LPS-induced activation of the NF-κB pathway in macrophages.

CONCLUSION

Knockdown of ANGPTL4 blocks the NF-κB pathway activation, hinders macrophage M1 polarization and pyroptosis, thereby suppressing sepsis-induced ALI.

An integrated RNA-Seq and network pharmacology approach for exploring the preventive effect of Corydalis bungeana Turcz. Extract and Acetylcorynoline on LPS-induced acute lung injury

ETHNOPHARMACOLOGICAL RELEVANCE

Corydalis bungeana Turcz. (KDD) is a Chinese herbal medicine with anti-inflammatory, lung cleansing, detoxification and other functions. Clinically, it is commonly used to treat respiratory infections. This study uses ALI as the research model, which is consistent with the clinical use of KDD. Acetylcorynoline (AC) is the main alkaloid component of the KDD extracts, and network pharmacology studies suggest that it may be the main active ingredient in the prevention of ALI.

AIM OF THE STUDY

The aim of this study is to explore the underlying mechanisms and to study the efficacy material basis of KDD in anti-ALI effect by LPS-induced mice and using a combination of RNA sequencing (RNA-Seq) technology and network pharmacology.

MATERIALS AND METHODS

Establish a mouse model of ALI by intraperitoneal injection of LPS (5 mg/kg). The main active ingredients of KDD were identified and analyzed by high performance liquid chromatography with quadrupole time-of-flight mass spectrometry (HPLC-QTOF-MS) and network pharmacology. IL-18, IL-1β, and IL-6 levels in serum and bronchoalveolar lavage fluid (BALF), lung histopathological changes, and lung myeloperoxidase (MPO) activity were assessed. We investigated the possible molecular mechanisms of KDD and AC in an LPS-induced mouse ALI models with RNA-Seq technology. In addition, the anti-inflammatory effect of AC was verified in vitro by establishing an LPS-stimulated RAW264.7 inflammation model. Molecular docking further validated AC as the efficacy material basis of KDD in anti-ALI.

RESULTS

Based on HPLC-QTOF-MS technology and network pharmacology, KDD is more strongly associated with lung tissue, and that AC may be the main active ingredient of KDD. Subsequently, in vivo experiments results showed that KDD and AC reduced the levels of pro-inflammatory cytokines in serum and BALF, reduced MPO levels and reduced inflammatory damage in the lungs. To elucidate its underlying mechanism, based on RNA-Seq analysis techniques performed in lung tissue, enrichment analysis showed that KDD and AC intervened through the NLR signaling pathway, thereby mitigating LPS-induced ALI. Then, RT-qPCR, IF, WB and other technologies were used to verify the anti-ALI core difference genes of KDD and AC from the gene transcription and protein expression levels of the NLR signaling pathway, and confirmed the anti-ALI. In vitro experimental results also showed that AC has anti-inflammatory effects in RAW264.7. Finally, the biotransformation and molecular docking results also further indicated that AC is the active ingredient of KDD in anti-ALI.

CONCLUSIONS

Studies have shown that KDD has a good therapeutic effect on ALI, and AC is the main pharmacodynamic material basis for its therapeutic effect in ALI.

Pyroptosis in septic lung injury: Interactions with other types of cell death

Sepsis is a life-threatening systemic inflammatory response syndrome caused by the host imbalanced response to infection. Lung injury is the most common complication of sepsis and one of the leading causes of patient death. Pyroptosis is a specific programmed cell death characterized by the release of inflammatory cytokines. Appropriate pyroptosis can reduce tissue damage and exert a protective effect against infection during sepsis. However, overactivated pyroptosis results in massive cell death, leading to septic shock, multiple organ dysfunction syndrome, and even an increased risk of secondary infection. Recent studies suggest that pyroptosis can interact with and cross-regulate other types of cell death programs to establish a complex network of cell death, which participates in the occurrence and development of septic lung injury. This review will focus on the interactions between pyroptosis and other types of cell death, including apoptosis, necroptosis, PANoptosis, NETosis, autophagy, and ferroptosis, to summarize the role of pyroptosis in sepsis-induced lung injury, and will discuss the potential therapeutic strategies of targeting pyroptosis during sepsis treatment.

METTL14 knockdown inhibits the pyroptosis in the sepsis-induced acute lung injury through regulating the m6A modification of NLRP3

Background: Sepsis has become one of the main factors inducing the development of acute lung injury (ALI) in clinical practice. Currently, inhibiting the activation of NLRP3 mediated pyroptosis is the target of multiple drugs in the treatment of sepsis induced ALI. This study aimed to explore the effects of METTL14 on the pyroptosis in the sepsis induced ALI progression.Methods: LPS-stimulated A549 cells and cecal ligation and puncture (CLP)-treated mice were used to establish the ALI model in vitro and in vivo. Then, the cell viability was measured by CCK-8 assay. ELISA kits were used to determine the IL-18 and IL-1β contents. Pyroptosis rate was tested by flow cytometry. M6A dot blot was conducted to analyze the global m6A levels and MeRIP assay was performed to detect the m6A levels of NLRP3. The relationship between METTL14 and NLRP3 was confirmed by RIP and dual-luciferase report assays.Results: The global m6A levels were significantly increased in the LPS-stimulated A549 cells and CLP-treated mice. METTL14 knockdown decreased the cell viability, IL-18 and IL-1β contents, and pyroptosis rate of the LPS-stimulated A549 cells. Furthermore, the increase of pyroptosis-related proteins in LPS-stimulated A549 cells was significantly decreased after METTL14 knockdown. Additionally, METTL14 knockdown decreased the m6A and mRNA levels of NLRP3, and NLRP3 overexpression reversed the effects of METTL14 knockdown on the pyroptosis in the LPS-stimulated A549 cells. In CLP-treated mice, METTL14 knockdown relieved the injury and decreased the IL-18 and IL-1β contents in the lung tissues, serum and bronchoalveolar lavage fluid.Conclusion: This study demonstrated that METTL14 knockdown inhibited the pyroptosis in the sepsis-induced ALI progression through decreasing the NLRP3 levels dependent on m6A methylation modification.

Ursodeoxycholic acid alleviates sepsis-induced lung injury by blocking PANoptosis via STING pathway

Acute lung injury (ALI), a progressive lung disease mostly caused by sepsis, is characterized by uncontrolled inflammatory responses, increased oxidative stress, pulmonary barrier dysfunction, and pulmonary edema. Ursodeoxycholic acid (UDCA) is a natural bile acid with various pharmacological properties and is extensively utilized in clinical settings for the management of hepatobiliary ailments. Nonetheless, the potential protective effects and mechanism of UDCA on sepsis-induced lung injuries remain unknown. In this study, we reported that UDCA effectively inhibited pulmonary edema, inflammatory cell infiltration, pro-inflammatory cytokines production, and oxidative stress. Furthermore, UDCA treatment significantly alleviated the damage of pulmonary barrier and enhanced alveolar fluid clearance. Importantly, UDCA treatment potently suppressed PANoptosis-like cell death which is demonstrated by the block of apoptosis, pyroptosis, and necroptosis. Mechanistically, UDCA treatment prominently inhibited STING pathway. And the consequential loss of STING substantially impaired the beneficial effects of UDCA treatment on the inflammatory response, pulmonary barrier, and PANoptosis. These results indicate that STING plays a pivotal role in the UDCA treatment against sepsis-induced lung injury. Collectively, our findings show that UDCA treatment can ameliorate sepsis-induced lung injury and verified a previously unrecognized mechanism by which UDCA alleviated sepsis-induced lung injury through blocking PANoptosis-like cell death via STING pathway.

Bisdemethoxycurcumin alleviates LPS-induced acute lung injury via activating AMPKα pathway

OBJECTIVE

Inflammation and oxidative stress contribute to the pathogenesis of acute lung injury (ALI), and subsequently result in rapid deterioration in health. Considering the indispensable role of bisdemethoxycurcumin (BDMC) in inflammation and oxidative stress, the present study aims to examine the effect of BDMC on sepsis-related ALI.

METHODS

C57BL/6 mice were administered with BDMC (100 mg/kg) or an equal volume of vehicle, and then injected with lipopolysaccharides (LPS) to induce ALI. We assessed the parameters of lung injury, inflammatory response and oxidative stress in lung tissues. Consistently, the macrophages with or without BDMC treatment were exposed to LPS to verify the effect of BDMC in vitro.

RESULTS

BDMC suppressed LPS-induced lung injury, inflammation and oxidative stress in vivo and in vitro. Mechanistically, BDMC increased the phosphorylation of AMPKα in response to LPS stimulation, and AMPK inhibition with Compound C almost completely blunted the protective effect of BDMC in LPS-treated mice and macrophages. Moreover, we demonstrated that BDMC activated AMPKα via the cAMP/Epac pathway.

CONCLUSION

Our study identifies the protective effect of BDMC against LPS-induced ALI, and the underlying mechanism may be related to the activation of cAMP/Epac/AMPKα signaling pathway.

Tiliroside Attenuates NLRP3 Inflammasome Activation in Macrophages and Protects against Acute Lung Injury in Mice

The Nod-like receptor family PYRIN domain containing 3 (NLRP3) inflammasome is a multiprotein signaling complex that plays a pivotal role in innate immunity, and the dysregulated NLRP3 inflammasome activation is implicated in various diseases. Tiliroside is a natural flavonoid in multiple medicinal and dietary plants with known anti-inflammatory activities. However, its role in regulating NLRP3 inflammasome activation and NLRP3-related disease has not been evaluated. Herein, it was demonstrated that tiliroside is inhibitory in activating the NLRP3 inflammasome in macrophages. Mechanistically, tiliroside promotes AMP-activated protein kinase (AMPK) activation, thereby leading to ameliorated mitochondrial damage as evidenced by the reduction of mitochondrial reactive oxygen species (ROS) production and the improvement of mitochondrial membrane potential, which is accompanied by attenuated NLRP3 inflammasome activation in macrophages. Notably, tiliroside potently attenuated lipopolysaccharide (LPS)-induced acute lung injury in mice, which has been known to be NLRP3 inflammasome dependent. For the first time, this study identified that tiliroside is an NLRP3 inflammasome inhibitor and may represent a potential therapeutic agent for managing NLRP3-mediated inflammatory disease.

Autophagy in sepsis-induced acute lung injury: Friend or foe?

Sepsis-induced acute lung injury (ALI) is a life-threatening syndrome with high mortality and morbidity, resulting in a heavy burden on family and society. As a key factor that maintains cellular homeostasis, autophagy is regarded as a self-digesting process by which damaged organelles and useless proteins are recycled for cell metabolism, and it thus plays a crucial role during physiological and pathological processes. Recent studies have indicated that autophagy is involved in the pathophysiological process of sepsis-induced ALI, including cell apoptosis, inflammation, and mitochondrial dysfunction, which indicates that regulating autophagy may be beneficial for this disease. However, the role of autophagy in the etiology and treatment of sepsis-induced ALI is not well characterized. This review summarizes the autophagy-related signaling pathways in sepsis-induced ALI, as well as focuses on the dual role of autophagy and its regulation by non-coding RNAs during disease progression, for the development of potential therapeutic strategies in this disease.

GBP2 upregulated in LPS-stimulated macrophages-derived exosomes accelerates septic lung injury by activating epithelial cell NLRP3 signaling

Macrophages infiltration is a crucial factor causing Sepsis-associated acute lung injury (ALI). Accumulating evidence suggests macrophages-alveolar epithelial cells communication is proven to be critical in ALI. However, little is known regarding how activated macrophages regulated sepsis-associated ALI. To explore the role of macrophages-alveolar epithelial cells communication in the ALI process, our data revealed that Lipopolysaccharides-induced macrophages-derived exosomes (L-Exo) induced sepsis-associated ALI and caused alveolar epithelial cells damage. Moreover, Guanylate-binding protein 2 (GBP2) was significantly upregulated in L-Exo, and NLRP3 inflammasomes was the direct target of GBP2. Further experimentation showed that GBP2 inhibition in vitro and in vivo reserves L-Exo effects, while GBP2 overexpression in vitro and in vivo promotes L-Exo effects. These results demonstrated that L-Exo contains excessive GBP2 and promotes inflammation through targeting NLRP3 inflammasomes, which induced alveolar epithelial cells dysfunction and pyroptosis. These findings demonstrate that L-Exo exerted a deleterious effect on ALI by regulating the GBP2/NLRP3 axis, which might provide new insight on ALI prevention and treatment.

Transcriptome analysis reveals the mechanism of pyroptosis-related genes in septic cardiomyopathy

Background

Septic cardiomyopathy (SC) is characterized by myocardial dysfunction caused by sepsis and constitutes one of the serious complications of sepsis. Pyroptosis is a unique proinflammatory programmed cell death process. However, the role of pyroptosis in the development of SC remains unclear, and further study is required. The purpose of this study is to identify pyroptosis-related genes (PRGs) in SC and explore the mechanism of pyroptosis involved in the regulation of SC formation and progression.

Methods

Differential expression analysis and enrichment analysis were performed on the SC-related dataset GSE79962 to identify differentially expressed genes (DEGs). PRGs were screened by intersecting genes associated with pyroptosis in previous studies with the DEGs obtained from GSE79962. The expression pattern of them was studied based on their raw expression data. Additionally, corresponding online databases were used to predict miRNAs, transcription factors (TFs) and therapeutic agents of PRGs. Lipopolysaccharide (LPS)-induced cell damage models in H9C2 and AC16 cell lines were constructed, cell activity was detected by CCK-8 and cell pyroptosis were detected by Hoechst33342/PI staining. Furthermore, these PRGs were verified in the external datasets (GSE53007 and GSE142615) and LPS-induced cell damage model. Finally, the effect of siRNA-mediated PRGs knockdown on the pyroptosis phenotype was examined.

Results

A total of 1,206 DEGs were screened, consisting of 663 high-expressed genes and 543 low-expressed genes. Among them, ten PRGs (SOD2, GJA1, TIMP3, TAP1, TIMP1, NOD1, TP53, CPTP, CASP1 and SAT1) were identified, and they were mainly enriched in "Pyroptosis", "Ferroptosis", "Longevity regulating pathway", and "NOD-like receptor signaling pathway". A total of 147 miRNAs, 31 TFs and 13 therapeutic drugs were predicted targeting the PRGs. The expression trends of SOD2 were confirmed in both the external datasets and LPS-induced cell damage models. Knockdown of SOD2 induced increased pyroptosis in the AC16 LPS-induced cell damage model.

Conclusions

In this study, we demonstrated that SOD2 is highly expressed in both the SC and LPS-induced cell damage models. Knockdown of SOD2 led to a significant increase in pyroptosis in the AC16 LPS-induced cell damage model. These findings suggest that SOD2 may serve as a potential target for the diagnosis and treatment of SC.

Apelin alleviates sepsis-induced acute lung injury in part by modulating the SIRT1/NLRP3 pathway to inhibit endothelial cell pyroptosis

BACKGROUND

Sepsis, an intricate systemic inflammatory syndrome, gives rise to various life-threatening complications, with acute lung injury (ALI) being prominently encountered. ALI, clinically characterized by pulmonary infiltration, hypoxemia, and edema, stands as a prevailing consequence of sepsis. This work sought to elucidate the mechanism of Apelin in mitigating sepsis-induced ALI (siALI).

METHODS

A mouse sepsis model was constructed by cecal ligation and puncture surgery, followed utilizing histopathological analysis using HE staining. mRNA levels of inflammatory cytokines (IL-1β, IL-6, and TNF-α) were assessed utilizing qRT-PCR, while ELISA was employed to measure the levels of vWF, VEGF, IL-1β, and IL-18. Western blot was conducted to examine protein levels of NLRP3, Caspase-1 p20, GSDMD-N, and SIRT1. To evaluate the extent of endothelial cell (EC) pyroptosis, immunofluorescence co-staining of CD31, NLRP3, and Caspase-1 p20 was fulfilled. Furthermore, TUNEL staining was utilized to ascertain the degree of plasma membrane damage and cell death.

RESULTS

Apelin demonstrated its potential in ameliorating siALI in mice by diminishing mRNA expression levels of pro-inflammatory cytokines (IL-1β, IL-6, TNF-α) as well as expression levels of vWF and VEGF. Apelin inhibited protein expression of NLRP3, Caspase-1 p20, and GSDMD-N, indicating that EC pyroptosis was suppressed. Finally, Apelin could upregulate the protein expression of SIRT1. This upregulation led to the inhibition of protein expression of NLRP3, Caspase-1 p20, and GSDMD-N, consequently suppressing EC pyroptosis. As a result, a reduction in the expression of inflammatory cytokines IL-1β and IL-18 ultimately alleviated siALI.

CONCLUSION

Apelin was confirmed to alleviate siALI partially by modulating SIRT1/NLRP3 pathway to inhibit EC pyroptosis, which dawned on the molecular mechanism of siALI and had important clinical significance for treating ALI effectively.

Pretreatment with Kahweol Attenuates Sepsis-Induced Acute Lung Injury via Improving Mitochondrial Homeostasis in a CaMKKII/AMPK-Dependent Pathway

SCOPE

It is well-established that dysregulated mitochondrial homeostasis in macrophages leads to inflammation, oxidative stress, and tissue damage, which are essential in the pathogenesis of sepsis-induced acute lung injury (ALI). Kahweol, a natural diterpene extracted from coffee beans, reportedly possesses anti-inflammatory and mitochondrial protective properties. Herein, the study investigates whether Kahweol can alleviate sepsis-induced ALI and explore the underlying mechanisms.

METHODS AND RESULTS

C57BL/6J mice are intraperitoneally injected with lipopolysaccharide (LPS) for 12 h to induce ALI. Pretreatment with kahweol by gavage for 5 days significantly alleviates lung pathological injury, inflammation, and oxidative stress, accompanied by shifting the dynamic process of mitochondria from fission to fusion, enhancing mitophagy, and activating AMPK. To investigate the underlying molecular mechanisms, differentiated THP-1 cells are cultured in a medium containing Kahweol for 12 h prior to LPS exposure, yielding consistent findings with the in vivo results. Moreover, AMPK inhibitors abrogate the above effects, indicating Kahweol acts in an AMPK-dependent manner. Furthermore, the study explores how Kahweol activates AMPK and finds that this process is mediated by CamKK II.

CONCLUSION

Pretreatment with Kahweol attenuates sepsis-induced acute lung injury via improving mitochondrial homeostasis in a CaMKKII/AMPK-dependent pathway and may be a potential candidate to prevent sepsis-induced ALI.

SIRT3 alleviates sepsis-induced acute lung injury by inhibiting pyroptosis via regulating the deacetylation of FoxO3a

OBJECTIVE

This study mainly analyzes the mechanism of SIRT3 alleviating sepsis-induced acute lung injury (ALI) by regulating the deacetylation of FoxO3a and inhibiting pyroptosis.

METHODS

SIRT3-overexpressing and silenced BEAS-2B cells were used to evaluate the effect of SIRT3 on apoptosis in LPS-treated lung epithelial cells. FoxO3a-silenced BEAS-2B cells were also used to verify the mechanism by which SIRT3 inhibited oxidative stress and pyroptosis in vitro in ALI. 3-TYP was used to inhibit the deacetylation function of SIRT3 in vivo. Pyroptosis was assessed by detecting GSDMD-N and LDH efflux.

RESULTS

In CLP-induced ALI mice, GSDMD-N and LDH levels were elevated, pyroptosis was induced. Silencing of SIRT3 exacerbated oxidative stress, NLRP3 activation and pyroptosis, and inhibited the deacetylation of FoxO3a. Overexpression of SIRT3 attenuated pyroptosis, induced deacetylation and restored the expression of FoxO3a and MnSOD. Silencing FoxO3a aggravated pyroptosis. Overexpression of SIRT3 restored the reduced FoxO3a expression and suppressed pyroptosis. 3-TYP blocked the promotion of FoxO3a by SIRT3 and the inhibitory effect of SIRT3 on pyroptosis.

CONCLUSION

The reduction of SIRT3 in sepsis caused hyperacetylation of FoxO3a, which in turn exacerbates oxidative stress and induces pyroptosis of ALI. Increasing the level of SIRT3 promotes FoxO3a through deacetylation, thereby inhibiting pyroptosis and relieving ALI.

ANGPTL2 aggravates LPS-induced septic cardiomyopathy via NLRP3-mediated inflammasome in a DUSP1-dependent pathway

Angiopoietin-like protein 2 (ANGPTL2) was implicated in various cardiovascular diseases; however, its role in lipopolysaccharide (LPS)-related septic cardiomyopathy remains unclear. Herein, mice were exposed to LPS to generate septic cardiomyopathy, and adeno-associated viral vector was employed to overexpress ANGPTL2 in the myocardium. Besides, mice were treated with adenoviral vector to knock down ANGPTL2 in hearts. ANGPTL2 expressions in hearts and cardiomyocytes were upregulated by LPS challenge. ANGPTL2 overexpression aggravated, while ANGPTL2 silence ameliorated LPS-associated cardiac impairment and inflammation. Mechanically, we found that ANGPTL2 activated NLRP3 inflammasome via suppressing DUSP1 signaling, and NLRP3 knockdown abrogated the detrimental role of ANGPTL2 in aggravating LPS-induced cardiac inflammation. Furthermore, DUSP1 overexpression significantly inhibited ANGPTL2-mediated NLRP3 activation, and subsequently improved LPS-related cardiac dysfunction. In summary, ANGPTL2 exacerbated septic cardiomyopathy via activating NLRP3-mediated inflammation in a DUSP1-dependent manner, and our study uncovered a promising therapeutic target in preventing septic cardiomyopathy.

Lianhua Qingke ameliorates lipopolysaccharide-induced lung injury by inhibiting neutrophil extracellular traps formation and pyroptosis

LHQK is a patented Traditional Chinese Medicine (TCM) which is clinically used for acute tracheobronchitis, cough, and other respiratory diseases. Recent studies have proved that LHQK exhibits excellent clinical efficacy in the treatment of acute lung injury (ALI). However, the corresponding mechanisms remain largely unexplored. In this study, we investigated the effects and the underlying mechanisms of LHQK on lipopolysaccharide (LPS)-induced ALI in mice. The pathological examination, inflammatory cytokines assessments, and mucus secretion evaluation indicated that administration of LHQK ameliorated LPS-induced lung injury, and suppressed the secretion of Muc5AC and pro-inflammatory cytokines (IL-6, TNF-α, and IL-1β) in plasma and BALF. Furthermore, the results of cell-free DNA level showed that LHQK significantly inhibited LPS-induced NETs formation. Western blot revealed that LHQK effectively inhibited LPS-triggered pyroptosis in the lung. In addition, RNA-Seq data analysis, relatively bioinformatic analysis, and network pharmacology analysis revealed that LHQK and relative components may play multiple protective functions in LPS-induced ALI/acute respiratory distress syndrome (ARDS) by regulating multiple targets directly or indirectly related to NETs and pyroptosis. In conclusion, LHQK can effectively attenuate lung injury and reduce lung inflammation by inhibiting LPS-induced NETs formation and pyroptosis, which may be regulated directly or indirectly by active compounds of LHQK.

A bibliometric analysis of programmed cell death in acute lung injury/acute respiratory distress syndrome from 2000 to 2022

Acute lung injury (ALI) is a prevalent critical disorder that disrupts the body's homeostasis in patients. The progression from ALI to acute respiratory distress syndrome (ARDS) is often accompanied by programmed cell death (PCD). However, there has been a lack of systematic research and comprehensive analysis on the role of different types of PCD in ALI/ARDS. This study aims to analyze the research status, trends, research hotspots, and compare the contribution of publications from different countries, institutions, journals and authors in the field of PCD in ALI/ARDS using bibliometric analysis. We collected publications regard to PCD and ALI/ARDS from Web of Science during 2000-2022. VOSviewer, Citespace, Scimago Graphica, Pajek, and GraphPad Prism 9.0 software were used for further analyzed and visualized. We identified a total of 3495 publications. The number of publications has increased since the beginning of the new century. China produced the most publications (1965), while the United States ranks first in the number of citations (40141). Shanghai Jiao Tong University and American Journal of Physiology-Lung Cellular and Molecular Physiology were the most prolific institution and journal, respectively. Wang, Ping has published most papers (23) while publications from Lee, Pj have most citations (2016). In terms of keywords, "apoptosis" and "inflammation" are the most frequently occurring, but there has been a recent shift from "apoptosis" and "autophagy" to "necroptosis", "pyroptosis", and "ferroptosis". Additionally, COVID-19 and long noncoding RNA (lncRNA) have become research hotspots in recent years. In conclusion, this bibliometric analysis reveals the research directions and frontier hotspots of PCD in ALI/ARDS. China and the United States have made important contributions to the development of this field. The research hotspots have recently focused on necroptosis, pyroptosis, ferroptosiss, COVID-19 and lncRNA.

Combination therapy with budesonide and acetylcysteine alleviates LPS-induced acute lung injury via the miR-381/NLRP3 molecular axis

BACKGROUND

Acute lung injury (ALI) usually has a high morbidity and mortality rate, but the current treatment is relatively scarce. Both budesonide (Bud) and N-acetylcysteine (NAC) exhibit protective effects in ALI, so we further investigated whether they have a synergistic effect on ALI when used together.

METHODS

Establishment of a rat model of ALI with Lipopolysaccharide (LPS). Bud and NAC were administered by nebulized inhalation alone or in combination. Subsequently, HE staining was performed to observe the pathological changes in lungs of rat. Evans blue staining was implemented to assess alveolar permeability, and the pulmonary edema was assessed by measuring the ratio of wet to dry weight of the lung. Moreover, a TUNEL kit was served to test apoptosis in lung tissues. Western blot and immunohistochemistry were analyzed for expression of scorch-related proteins and NLRP3 in lung tissue, respectively. ELISA was implemented to detect inflammatory factor levels in BALF. and RT-qPCR was utilized to assess the expression level of miR-381. After stable transfection of miR-381 inhibitor or OE-NLRP3 in BEAS-2B treated with LPS, Bud and NAC, miR-381 expression was assessed by RT-qPCR, scorch death-related protein expression was measured by western blot, cell proliferation/viability was assayed by CCK-8, apoptosis was measured by flow cytometry, and ELISA was implemented to assess inflammatory factor levels. Furthermore, the Dual-luciferase assay was used to verify the targeting relationship.

RESULTS

Bud and NAC treatment alone or in combination with nebulized inhalation attenuated the increased alveolar permeability, pulmonary edema, inflammatory response and scorching in LPS-induced ALI rats, and combined treatment with Bud and NAC was the most effective. In addition, combined treatment with Bud and NAC upregulated miR-381 expression and inhibited NLRP3 expression in cellular models and LPS-induced ALI rats. Transfection of the miR-381 inhibitor and OE-NLRP3 partially reversed the protective effects of Bud and NAC combination treatment on BEAS-2B cell proliferation inhibition, apoptosis, focal death and the inflammatory response.

CONCLUSION

Combined Bud and NAC nebulization therapy alleviates LPS-induced ALI by modulating the miR-381/NLRP3 molecular axis.

HDAC3 promotes macrophage pyroptosis via regulating histone deacetylation in acute lung injury

Activated inflammation and pyroptosis in macrophage are closely associated with acute lung injury (ALI). Histone deacetylase 3 (HDAC3) serves as an important enzyme that could repress gene expression by mediating chromatin remodeling. In this study, we found that HDAC3 was highly expressed in lung tissues of lipopolysaccharide (LPS)-treated mice. Lung tissues from macrophage HDAC3-deficient mice stimulated with LPS showed alleviative lung pathological injury and inflammatory response. HDAC3 silencing significantly blocked the activation of cyclic GMP-AMP synthase (cGAS)/stimulator of interferon genes (STING) pathway in LPS-induced macrophage. LPS could recruit HDAC3 and H3K9Ac to the miR-4767 gene promoter, which repressed the expression of miR-4767 to promote the expression of cGAS. Taken together, our findings demonstrated that HDAC3 played a pivotal role in mediating pyroptosis in macrophage and ALI by activating cGAS/STING pathway through its histone deacetylation function. Targeting HDAC3 in macrophage may provide a new therapeutic target for the prevention of LPS-induced ALI.

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

Sepsis is one common cause of acute lung injury (ALI) and acute respiratory distress syndrome (ARDS), which is closely associated with high mortality in intensive care units (ICU). Histone deacetylase 3 (HDAC3) serves as an important epigenetic modifying enzyme which could affect chromatin structure and transcriptional regulation. Here, we explored the effects of HDAC3 in type II alveolar epithelial cells (AT2) on lipopolysaccharide (LPS)-induced ALI and shed light on potential molecular mechanisms. We generated ALI mouse model with HDAC3 conditional knockout mice (Sftpc-cre; Hdac3^f/f) in AT2 and the roles of HDAC3 in ALI and epithelial barrier integrity were investigated in LPS-treated AT2. The levels of HDAC3 were significantly upregulated in lung tissues from mice with sepsis and in LPS-treated AT2. HDAC3 deficiency in AT2 not only decreased inflammation, apoptosis, and oxidative stress, but also maintained epithelial barrier integrity. Meanwhile, HDAC3 deficiency in LPS-treated AT2 preserved mitochondrial quality control (MQC), evidenced by the shift of mitochondria from fission into fusion, decreased mitophagy, and improved fatty acid oxidation (FAO). Mechanically, HDAC3 promoted the transcription of Rho-associated protein kinase 1 (ROCK1) in AT2. In the context of LPS stimulation, the upregulated ROCK1 elicited by HDAC3 could be phosphorylated by Rho-associated (RhoA), thus disturbing MQC and triggering ALI. Furthermore, we found that forkhead box O1 (FOXO1) was one of transcription factors of ROCK1. HDAC3 directly decreased the acetylation of FOXO1 and promoted its nuclear translocation in LPS-treated AT2. Finally, HDAC3 inhibitor RGFP966 alleviated epithelial damage and improved MQC in LPS-treated AT2. Altogether, HDAC3 deficiency in AT2 alleviated sepsis-induced ALI by preserving mitochondrial quality control via FOXO1-ROCK1 axis, which provided a potential strategy for the treatment of sepsis and ALI.

A cross-talk between sestrins, chronic inflammation and cellular senescence governs the development of age-associated sarcopenia and obesity

The rapid increase in both the lifespan and proportion of older adults is accompanied by the unprecedented rise in age-associated chronic diseases, including sarcopenia and obesity. Aging is also manifested by increased susceptibility to multiple endogenous and exogenous stresses enabling such chronic conditions to develop. Among the main physiological regulators of cellular adaption to various stress stimuli, such as DNA damage, hypoxia, and oxidative stress, are sestrins (Sesns), a family of three evolutionarily conserved proteins, Sesn1, 2, and 3. Age-associated sarcopenia and obesity are characterized by two key processes: (i) accumulation of senescent cells in the skeletal muscle and adipose tissue and (ii) creation of a systemic, chronic, low-grade inflammation (SCLGI). Presumably, failed SCLGI resolution governs the development of these chronic conditions. Noteworthy, Sesns activate senolytics, which are agents that selectively eliminate senescent cells, as well as specialized pro-resolving mediators, which are factors that physiologically provide inflammation resolution. Sesns reveal clear beneficial effects in pre-clinical models of sarcopenia and obesity. Based on these observations, we propose a novel treatment strategy for age-associated sarcopenia and obesity, complementary to the conventional therapeutic modalities: Sesn activation, SCLGI resolution, and senescent cell elimination.

Targeting immunometabolism against acute lung injury

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are life-threatening conditions triggered by multiple intra- and extra-pulmonary injury factors, characterized by complicated molecular mechanisms and high mortality. Great strides have been made in the field of immunometabolism to clarify the interplay between intracellular metabolism and immune function in the past few years. Emerging evidence unveils the crucial roles of immunometabolism in inflammatory response and ALI. During ALI, both macrophages and lymphocytes undergo robust metabolic reprogramming and discrete epigenetic changes after activated. Apart from providing ATP and biosynthetic precursors, these metabolic cellular reactions and processes in lung also regulate inflammation and immunity.In fact, metabolic reprogramming involving glucose metabolism and fatty acidoxidation (FAO) acts as a double-edged sword in inflammatory response, which not only drives inflammasome activation but also elicits anti-inflammatory response. Additionally, the features and roles of metabolic reprogramming in different immune cells are not exactly the same. Here, we outline the evidence implicating how adverse factors shape immunometabolism in differentiation types of immune cells during ALI and summarize key proteins associated with energy expenditure and metabolic reprogramming. Finally, novel therapeutic targets in metabolic intermediates and enzymes together with current challenges in immunometabolism against ALI were discussed.

Kirenol inhibits inflammation challenged by lipopolysaccharide through the AMPK-mTOR-ULK1 autophagy pathway

Kirenol is a bioactive substance isolated from Herba Siegesbeckiae. Although the anti-inflammatory activity of kirenol has been well documented, its role in autophagy remains unknown. The present study aimed to investigate the protective role of kirenol on inflammation challenged by lipopolysaccharide (LPS) in acute lung injury (ALI) cell and mouse models and unravel the underlying mechanisms, with a particular focus on autophagy. For this purpose, an ALI cell and mouse models were established, and the effects of kirenol on the expression of molecules related to inflammation and autophagy were examined. The present results revealed that kirenol could significantly inhibit inflammatory cytokines secretion in cells and in the mice injured by LPS; this effect may be attributed to enhanced autophagy as evidenced by the up-regulation of LC3-II and the down-regulation of p62 both in vitro and in vivo. Phosphorylated AMPK and ULK1 increased, while phosphorylated mTOR decreased in the kirenol-treated ALI cell model. Moreover, inhibition of autophagy using AMPK inhibitor or 3-MA or chloroquine (CQ) reversed the anti-inflammatory and autophagy-enhancement effects of kirenol exposure in vitro, indicating that kirenol could enhance autophagy by activating the AMPK-mTOR-ULK1 pathway. The results of RNA sequencing suggested that kirenol was strongly related to the biological functions of acute inflammatory response and the AMPK signaling pathway. Further in vivo ALI mouse model studies demonstrated the protective role of kirenol against lung inflammation, such as improved histopathology, decreased lung edema, and leukocyte infiltration were abolished by 3-MA. These findings implicate that kirenol can inhibit LPS-induced inflammation via the AMPK-mTOR-ULK1 autophagy pathway.

Impact of chronic cold exposure on lung inflammation, pyroptosis and oxidative stress in mice

Chronic cold exposure, which is the main inducer of lung diseases in high latitudes, affects production efficiency and restricts the development of aquaculture. Although the relationship between cold exposure and susceptibility to the lungs is widely accepted, but the influence between them has not been fully explored. The aim of this study is to understand the underlying mechanism. In the present study, the mice, which are used to establish cold stress (CS)-induced lung injury model, are exposed to cold temperature (4 °C) for 3 h each day for 4 weeks. The results indicate that the expression of heat shock protein 70 (HSP70) is augmented by cold exposure. In addition, chronic cold exposure aggravate the formation of malondialdehyde (MDA) and lead to a significant decrease in the contents of micrococcus catalase (CAT) and glutathione (GSH). Moreover, chronic cold exposure significantly exacerbates the expression of inflammation- and apoptosis-related proteins. The activation of Bax and caspase-3 are significantly augmented. However, that of Bcl-2 is decreased. These results are different from those in room team. The results show that chronic cold exposure plays an important roles in the activation of multiple signaling pathways, such as pyroptosis-related, inflammation-related and oxidative stress-regulated signaling pathways. In summary, these investigations support that chronic cold exposure increase the risk of lung injury by activating inflammation, oxidative stress and pyroptosis.

Genome-wide exploration of a pyroptosis-related gene module along with immune cell infiltration patterns in bronchopulmonary dysplasia

Pyroptosis plays a crucial role in bronchopulmonary dysplasia (BPD) and is associated with various lung injury illnesses. However, the function of pyroptosis-related genes (PRGs) in BPD remains poorly understood. The gene expression omnibus (GEO) database was searched for information on genes associated with BPD. Twenty-five BPD-related DE-PRGs were identified, all of which were closely associated with pyroptosis regulation and immunological response. LASSO and SVM-RFE algorithms identified CHMP7, NLRC4, NLRP2, NLRP6, and NLRP9 among the 25 differentially expressed PRGs as marker genes with acceptable diagnostic capabilities. Using these five genes, we also generated a nomogram with excellent predictive power. Annotation enrichment analyses revealed that these five genes may be implicated in BPD and numerous BPD-related pathways. In addition, the ceRNA network showed an intricate regulatory link based on the marker genes. In addition, CIBERSORT-based studies revealed that alterations in the immunological microenvironment of BPD patients may be associated with the marker genes. We constructed a diagnostic nomogram and gave insight into the mechanism of BPD. Its diagnostic value for BPD must be evaluated in further research before it can be used in clinical practice.

Growth Differentiation Factor 7 Prevents Sepsis-Induced Acute Lung Injury in Mice

Objective

Acute lung injury (ALI) is a life-threatening complication during sepsis and contributes to multiple organ failure and high mortality for septic patients. The present study aims to investigate the role and molecular basis of growth differentiation factor 7 (GDF7) in sepsis-induced ALI.

Methods

Mice were subcutaneously injected with recombinant mouse GDF7 Protein (rmGDF7) and then intratracheally injected with lipopolysaccharide (LPS) to generate sepsis-induced ALI. Primary peritoneal macrophages were isolated to further evaluate the role and underlying mechanism of GDF7 in vitro.

Results

GDF7 was downregulated in LPS-stimulated lung tissues, and rmGDF7 treatment significantly inhibited inflammation and oxidative stress in ALI mice, thereby preventing LPS-induced pulmonary injury and dysfunction. Mechanistically, we found that rmGDF7 activated AMP-activated protein kinase (AMPK), and AMPK inhibition significantly blocked the anti-inflammatory and antioxidant effects of rmGDF7 during LPS-induced ALI. Further findings revealed that rmGDF7 activated AMPK through a downregulated stimulator of interferon gene (STING) in vivo and in vitro.

Conclusion

GDF7 prevents LPS-induced inflammatory response, oxidative stress, and ALI by regulating the STING/AMPK pathway. Our findings for the first time identify GDF7 as a potential agent for the treatment of sepsis-induced ALI.

The role of AMPK-Sirt1-autophagy pathway in the intestinal protection process by propofol against regional ischemia/reperfusion injury in rats

Intestinal ischemia/reperfusion (II/R) is a clinical event associated with high morbidity and mortality. AMP-activated protein kinase (AMPK), a central cellular energy sensor, is associated with oxidative stress and inflammation. However, whether the AMPK is involved in the II/R-induced intestinal injury and the underlying mechanism is yet to be elucidated. Propofol has a protective effect on organs; yet, its specific mechanism of action remains unclear. This study explored the role of the AMPK-Sirt1-autophagy pathway in intestinal injury, and whether propofol could reduce intestinal injury and investigated the mechanisms in a rat model of II/R injury as well as a cell model (IEC-6 cells) of hypoxia/reoxygenation (H/R). Propofol, AMPK agonist (AICAR) and AMPK inhibitor (Compound C) were then administered, respectively. The histopathological changes, cell viability and apoptosis were detected. Furthermore, the levels of proinflammatory factors, the activities of oxidative stress, diamine oxidase, and signaling pathway were also analyzed. The results demonstrated that the AMPK-Sirt1-autophagy pathway of intestine was activated after II/R or H/R. Propofol could further activate the pathway, which reduced intestinal injury, inhibited apoptosis, reversed inflammation and oxidative stress, and improved the 24-hour survival rate in II/R rats in vivo, and attenuated H/R-induced IEC-6 cell injury, oxidative stress, and apoptosis in vitro, as fine as changes in AICAR treatment. Compound C abrogated the protective effect of propofol on II/R and H/R-induced injury. These results suggested a crucial effect of AMPK on the mechanism of intestinal injury and might provide a new insight into the mechanism of propofol reducing II/R injury.

Progress in preclinical studies of macrophage autophagy in the regulation of ALI/ARDS

Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) is a critical clinical syndrome with high morbidity and mortality that poses a major challenge in critical care medicine. The development of ALI/ARDS involves excessive inflammatory response, and macrophage autophagy plays an important role in regulating the inflammatory response in ALI/ARDS. In this paper, we review the effects of autophagy in regulating macrophage function, discuss the roles of macrophage autophagy in ALI/ARDS, and highlight drugs and other interventions that can modulate macrophage autophagy in ALI/ARDS to improve the understanding of the mechanism of macrophage autophagy in ALI/ARDS and provide new ideas and further research directions for the treatment of ALI/ARDS.

Molecular mechanisms and functions of pyroptosis in sepsis and sepsis-associated organ dysfunction

Sepsis, a life-threatening organ dysfunction caused by a dysregulated host response to infection, is a leading cause of death in intensive care units. The development of sepsis-associated organ dysfunction (SAOD) poses a threat to the survival of patients with sepsis. Unfortunately, the pathogenesis of sepsis and SAOD is complicated, multifactorial, and has not been completely clarified. Recently, numerous studies have demonstrated that pyroptosis, which is characterized by inflammasome and caspase activation and cell membrane pore formation, is involved in sepsis. Unlike apoptosis, pyroptosis is a pro-inflammatory form of programmed cell death that participates in the regulation of immunity and inflammation. Related studies have shown that in sepsis, moderate pyroptosis promotes the clearance of pathogens, whereas the excessive activation of pyroptosis leads to host immune response disorders and SAOD. Additionally, transcription factors, non-coding RNAs, epigenetic modifications and post-translational modifications can directly or indirectly regulate pyroptosis-related molecules. Pyroptosis also interacts with autophagy, apoptosis, NETosis, and necroptosis. This review summarizes the roles and regulatory mechanisms of pyroptosis in sepsis and SAOD. As our understanding of the functions of pyroptosis improves, the development of new diagnostic biomarkers and targeted therapies associated with pyroptosis to improve clinical outcomes appears promising in the future.

Pyroptosis in inflammation-related respiratory disease

Pyroptosis is commonly induced by the gasdermin (GSDM) family and is accompanied by the release of inflammatory cytokines such as IL-1β and IL-18. Recently, increasing evidence suggests that pyroptosis plays a role in respiratory diseases. This review aimed to summarize the roles and mechanisms of pyroptosis in inflammation-related respiratory diseases. There are several pathways involved in pyroptosis, such as the canonical inflammasome-induced pathway, non-canonical inflammasome-induced pathway, caspase-1/3/6/7/GSDMB pathway, caspase-8/GSDMC pathway, caspase-8/GSDMD pathway, and caspase-3/GSEME pathway. Pyroptosis may be involved in asthma, chronic obstructive pulmonary disease (COPD), lung cancer, acute lung injury (ALI), silicosis, pulmonary hypertension (PH), and tuberculosis (TB), in which the NLRP3 inflammasome-induced pathway is mostly highlighted. Pyroptosis contributes to the deterioration of asthma, COPD, ALI, silicosis, and PH. In addition, pyroptosis has dual effects on lung cancer and TB. Additionally, whether pyroptosis participates in cystic fibrosis (CF) and sarcoidosis or not is largely unknown, though the activation of NLRP3 inflammasome is found in CF and sarcoidosis. In conclusion, pyroptosis may play a role in inflammation-related respiratory diseases, providing new therapeutic targets.