Acute lung injury is a leading cause of death in bacterial sepsis due to the wholesale destruction of the lung endothelial barrier, which results in protein-rich lung edema, influx of proinflammatory leukocytes, and intractable hypoxemia. Pyroptosis is a form of programmed lytic cell death that is triggered by inflammatory caspases, but little is known about its role in EC death and acute lung injury. Here, we show that systemic exposure to the bacterial endotoxin lipopolysaccharide (LPS) causes severe endothelial pyroptosis that is mediated by the inflammatory caspases, human caspases 4/5 in human ECs, or the murine homolog caspase-11 in mice in vivo. In caspase-11-deficient mice, BM transplantation with WT hematopoietic cells did not abrogate endotoxemia-induced acute lung injury, indicating a central role for nonhematopoietic caspase-11 in endotoxemia. Additionally, conditional deletion of caspase-11 in ECs reduced endotoxemia-induced lung edema, neutrophil accumulation, and death. These results establish the requisite role of endothelial pyroptosis in endotoxemic tissue injury and suggest that endothelial inflammatory caspases are an important therapeutic target for acute lung injury.Caspase-11-mediated endothelial pyroptosis underlies endotoxemia-induced lung injury The Journal of Clinical Investigation R E S E A R C H A R T I C L E4 1 2 5 jci.org Volume 127 Number 11 November 2017the complex process of inflammation involves multiple programmed cell death pathways, depending on the type and magnitude of the inciting stimulus and cell type. From an evolutionary perspective, pyroptosis of cells harboring intracellular bacteria or in which LPS has breached the plasma membrane is an effective means of eliminating an intracellular bacterial niche and activating the host through release of inflammatory mediators such as IL-1β, while sparing uninfected neighboring cells (13,(28)(29)(30). Thus, pyroptosis induced by inflammatory caspases 1/4/5/11 is an innate immune response distinct from the canonical inflammasome activation pathway via cell-surface TLR4 (11,(31)(32)(33)(34). However, caspase-11 can also be immunopathologic in sepsis (35). Caspase-11-deficient mice were protected in endotoxemic shock (10,11), suggesting that in the setting of an overwhelming inflammatory response, the potentially protective pyroptotic mechanism activates an exaggerated pathologic response due to overwhelming cell lysis. The role of the inflammatory caspases 4/5/11 in mediating cytoplasmic LPS signaling and pyroptosis has until now been primarily studied in macrophages or dendritic cells (11,12,14,28,32,36). Their role in destroying the endothelial barrier through widespread endothelial death and pathogenesis of ALI remains unknown. Here, we tested the hypothesis that lung ECs are a primary target for pyroptosis via intracellular sensing of LPS by the inflammatory caspases 4/5/11 and that endothelial pyroptosis is required for the induction of ALI. Results LPS in ECs induces pyroptotic cell death via activation of inflammatory cas...

BackgroundThe anaplastic lymphoma kinase (ALK) gene is frequently involved in translocations that lead to gene fusions in a variety of human malignancies, including lymphoma and lung cancer. Fusion partners of ALK include NPM, EML4, TPM3, ATIC, TFG, CARS, and CLTC. Characterization of ALK fusion patterns and their resulting clinicopathological profiles could be of great benefit in better understanding the biology of lung cancer.ResultsRACE-coupled PCR sequencing was used to assess ALK fusions in a cohort of 103 non-small cell lung carcinoma (NSCLC) patients. Within this cohort, the EML4-ALK fusion gene was identified in 12 tumors (11.6%). Further analysis revealed that EML4-ALK was present at a frequency of 16.13% (10/62) in patients with adenocarcinomas, 19.23% (10/52) in never-smokers, and 42.80% (9/21) in patients with adenocarcinomas lacking EGFR and KRAS mutations. The EML4-ALK fusion was associated with non-smokers (P = 0.03), younger age of onset (P = 0.03), and adenocarcinomas without EGFR/KRAS mutations (P = 0.04). A trend towards improved survival was observed for patients with the EML4-ALK fusion, although it was not statistically significant (P = 0.20). Concurrent deletion in EGFR exon 19 and fusion of EML4-ALK was identified for the first time in a Chinese female patient with an adenocarcinoma. Analysis of ALK expression revealed that ALK mRNA levels were higher in tumors positive for the EML-ALK fusion than in negative tumors (normalized intensity of 21.99 vs. 0.45, respectively; P = 0.0018). However, expression of EML4 did not differ between the groups.ConclusionsThe EML4-ALK fusion gene was present at a high frequency in Chinese NSCLC patients, particularly in those with adenocarcinomas lacking EGFR/KRAS mutations. The EML4-ALK fusion appears to be tightly associated with ALK mRNA expression levels. RACE-coupled PCR sequencing is a highly sensitive method that could be used clinically for the identification of EML4-ALK-positive patients.

The relative EGFR mutation abundance could predict benefit from EGFR-TKI treatment for advanced NSCLC.