Ferrostatin-1 alleviates ventilator-induced lung injury by inhibiting ferroptosis.

Ventilator-induced lung injury (VILI) has become an increasingly common complication in the clinic concerning mechanical ventilation. Previous research showed that VILI is the result of a response to cascade inflammation; however, the inflammatory mechanism involved remains unclear. As a newly recognized form of cell death, ferroptosis can release damage-related molecules (DAMPs) to trigger and amplify the inflammatory response and is involved in several inflammatory diseases. The present study aimed to investigate a previously unrecognized role of ferroptosis in VILI. A mouse model of VILI and a model of cyclic stretching (CS)-induced lung epithelial cell injury were established. Mice and cells were pretreated with ferrostain-1, an inhibitor of ferroptosis. Lung tissue and cells were then harvested to determine lung injury, inflammatory responses, indicators and protein expression associated with ferroptosis. Compared to the control group, mice subjected to high tidal volumes (HTV) for 4 h showed more severe pulmonary edema and inflammation and the activation of ferroptosis. Ferrostain-1 significantly ameliorated histological injury and inflammation in the VILI mouse and alleviated CS-induced lung epithelial cell injury. Mechanistically, ferrostain-1 markedly limited the activation of ferroptosis and recovered functionality of the SLC7A11/GPX4 axis both in vitro and in vivo, thus demonstrating its potential as a novel therapeutic target for VILI.

Identification of hub genes associated with acute kidney injury induced by renal ischemia-reperfusion injury in mice.

Background: Acute kidney injury (AKI) is a severe clinical syndrome, and ischemia-reperfusion injury is an important cause of acute kidney injury. The aim of the present study was to investigate the related genes and pathways in the mouse model of acute kidney injury induced by ischemia-reperfusion injury (IRI-AKI). Method: Two public datasets (GSE39548 and GSE131288) originating from the NCBI Gene Expression Omnibus (GEO) database were analyzed using the R software limma package, and differentially expressed genes (DEGs) were identified. Gene Ontology (GO) and Kyoto Encyclopedia of Genomes (KEGG) and gene set enrichment analysis (GSEA) were performed using the differentially expressed genes. Furthermore, a protein-protein interaction (PPI) network was constructed to investigate hub genes, and transcription factor (TF)-hub gene and miRNA-hub gene networks were constructed. Drugs and molecular compounds that could interact with hub genes were predicted using the DGIdb. Result: A total of 323 common differentially expressed genes were identified in the renal ischemia-reperfusion injury group compared with the control group. Among these, 260 differentially expressed genes were upregulated and 66 differentially expressed genes were downregulated. Gene Ontology enrichment and Kyoto Encyclopedia of Genes and Genomes analysis results showed that these common differentially expressed genes were enriched in positive regulation of cytokine production, muscle tissue development, and other biological processes, indicating that they were involved in mitogen-activated protein kinase (MAPK), PI3K-Akt, TNF, apoptosis, and Epstein-Barr virus infection signaling pathways. Protein-protein interaction analysis showed 10 hub genes, namely, Jun, Stat3, MYC, Cdkn1a, Hif1a, FOS, Atf3, Mdm2, Egr1, and Ddit3. Using the STRUST database, starBase database, and DGIdb database, it was predicted that 34 transcription factors, 161 mi-RNAs, and 299 drugs or molecular compounds might interact with hub genes. Conclusion: Our findings may provide novel potential biomarkers and insights into the pathogenesis of ischemia-reperfusion injury-acute kidney injury through a comprehensive analysis of Gene Expression Omnibus data, which may provide a reliable basis for early diagnosis and treatment of ischemia-reperfusion injury-acute kidney injury.

Inhibition of IP3R/Ca2+ Dysregulation Protects Mice From Ventilator-Induced Lung Injury via Endoplasmic Reticulum and Mitochondrial Pathways.

Rationale: Disruption of intracellular calcium (Ca2+) homeostasis is implicated in inflammatory responses. Here we investigated endoplasmic reticulum (ER) Ca2+ efflux through the Inositol 1,4,5-trisphosphate receptor (IP3R) as a potential mechanism of inflammatory pathophysiology in a ventilator-induced lung injury (VILI) mouse model. Methods: C57BL/6 mice were exposed to mechanical ventilation using high tidal volume (HTV). Mice were pretreated with the IP3R agonist carbachol, IP3R inhibitor 2-aminoethoxydiphenyl borate (2-APB) or the Ca2+ chelator BAPTA-AM. Lung tissues and bronchoalveolar lavage fluid (BALF) were collected to measure Ca2+ concentrations, inflammatory responses and mRNA/protein expression associated with ER stress, NLRP3 inflammasome activation and inflammation. Analyses were conducted in concert with cultured murine lung cell lines. Results: Lungs from mice subjected to HTV displayed upregulated IP3R expression in ER and mitochondrial-associated-membranes (MAMs), with enhanced formation of MAMs. Moreover, HTV disrupted Ca2+ homeostasis, with increased flux from the ER to the cytoplasm and mitochondria. Administration of carbachol aggravated HTV-induced lung injury and inflammation while pretreatment with 2-APB or BAPTA-AM largely prevented these effects. HTV activated the IRE1α and PERK arms of the ER stress signaling response and induced mitochondrial dysfunction-NLRP3 inflammasome activation in an IP3R-dependent manner. Similarly, disruption of IP3R/Ca2+ in MLE12 and RAW264.7 cells using carbachol lead to inflammatory responses, and stimulated ER stress and mitochondrial dysfunction. Conclusion: Increase in IP3R-mediated Ca2+ release is involved in the inflammatory pathophysiology of VILI via ER stress and mitochondrial dysfunction. Antagonizing IP3R/Ca2+ and/or maintaining Ca2+ homeostasis in lung tissue represents a prospective treatment approach for VILI.

TLR4/TRAF6/NOX2 signaling pathway is involved in ventilation-induced lung injury via endoplasmic reticulum stress in murine model.

In ventilation-induced lung injury (VILI), prolonged nonpathogen-mediated inflammation is triggered as a result of alveolar hyperinflation. In our previous study, we suggested that endoplasmic reticulum (ER) stress-mediated inflammation was involved in VILI, but how ER stress is triggered remains unknown. Toll-like receptor 4 (TLR4) activation plays an important role in mechanical ventilation (MV)-induced lung inflammation, however, it is unknown whether ER stress is activated by TLR4 to participate in VILI. In this study, C57BL/6 mice were exposed to MV with high tidal volumes (HTV 20 ml/kg). Mice were pretreated with TAK-242 the TLR4 inhibitor, C25-140, the TRAF6 inhibitor, or GSK2795039, the NOX2 inhibitor. Lung tissue and bronchoalveolar lavage fluid (BALF) were collected to measure lung injury, inflammatory responses and mRNA/protein expression associated with ER stress and the TLR4/TRAF6/NOX2 signaling pathway. Our results indicate that MV with HTV caused the TLR4/TRAF6/NOX2 signaling pathway activation and production of large amounts of ROS, which led to ER stress and NF-κB mediated inflammation in VILI. Furthermore, TLR4/TRAF6/NOX2 signaling pathway inhibition attenuated ER stress response and alleviate lung injury in mice.