ELOVL6 deficiency aggravates allergic airway inflammation through the ceramide-S1P pathway in mice.

BACKGROUND: Elongation of very-long-chain fatty acids protein 6 (ELOVL6), an enzyme regulating elongation of saturated and monounsaturated fatty acids with C12 to C16 to those with C18, has been recently indicated to affect various immune and inflammatory responses; however, the precise process by which ELOVL6-related lipid dysregulation affects allergic airway inflammation is unclear. OBJECTIVES: This study sought to evaluate the biological roles of ELOVL6 in allergic airway responses and investigate whether regulating lipid composition in the airways could be an alternative treatment for asthma. METHODS: Expressions of ELOVL6 and other isoforms were examined in the airways of patients who are severely asthmatic and in mouse models of asthma. Wild-type and ELOVL6-deficient (Elovl6-/-) mice were analyzed for ovalbumin-induced, and also for house dust mite-induced, allergic airway inflammation by cell biological and biochemical approaches. RESULTS: ELOVL6 expression was downregulated in the bronchial epithelium of patients who are severely asthmatic compared with controls. In asthmatic mice, ELOVL6 deficiency led to enhanced airway inflammation in which lymphocyte egress from lymph nodes was increased, and both type 2 and non-type 2 immune responses were upregulated. Lipidomic profiling revealed that the levels of palmitic acid, ceramides, and sphingosine-1-phosphate were higher in the lungs of ovalbumin-immunized Elovl6-/- mice compared with those of wild-type mice, while the aggravated airway inflammation was ameliorated by treatment with fumonisin B1 or DL-threo-dihydrosphingosine, inhibitors of ceramide synthase and sphingosine kinase, respectively. CONCLUSIONS: This study illustrates a crucial role for ELOVL6 in controlling allergic airway inflammation via regulation of fatty acid composition and ceramide-sphingosine-1-phosphate biosynthesis and indicates that ELOVL6 may be a novel therapeutic target for asthma.

Negative-pressure pulmonary Hemorrhaging Due to Severe Obstructive Sleep Apnea.

A 24-year-old man with a history of bloody sputum for 6 months was referred to our hospital with suspected alveolar hemorrhaging due to vasculitis. Chest computed tomography showed ground-glass opacities in both lungs, and an examination of his bronchoalveolar lavage fluid showed alveolar hemorrhaging. However, no evidence of vasculitis was found, and subsequent polysomnographic testing confirmed that he had severe obstructive sleep apnea (OSA). Since the alveolar hemorrhaging improved after the initiation of continuous positive airway pressure treatment, the diagnosis was negative-pressure alveolar hemorrhaging due to severe OSA.

A case of ROS1-rearranged lung adenocarcinoma exhibiting pleural effusion caused by crizotinib.

Reports of crizotinib-induced pleural effusion in non-small cell lung cancer (NSCLC) are limited. A 35-year-old Japanese woman was diagnosed with ROS1-rearranged lung adenocarcinoma (primary left lower lobe, cT4N3M1c). Crizotinib was administered as first-line therapy, and the primary and mediastinal hilar lymph node metastases rapidly shrank. On the fourth day of treatment, chest X-ray demonstrated contralateral pleural effusion. On the 41st day of treatment, crizotinib was discontinued because of grade 3 neutropenia. Examination including surgical thoracoscopy did not reveal causative findings, and the continued cessation of drug administration enabled the right pleural effusion to decrease gradually and disappear, suggesting that this event was a side effect of crizotinib. The disease did not progress even though the drug was withdrawn for more than one year. In conclusion, crizotinib was considered to cause pleural effusion as an adverse event in a case of ROS1-rearranged lung adenocarcinoma with a complete response.