miR-4739 mediates pleural fibrosis by targeting bone morphogenetic protein 7.

BACKGROUND: Pleural fibrosis is defined as excessive depositions of matrix components that result in pleural tissue architecture destruction and dysfunction. In severe cases, the progression of pleural fibrosis leads to lung entrapment, resulting in dyspnea and respiratory failure. However, the mechanism of pleural fibrosis is poorly understood. METHODS: miR-4739 levels were detected by miRNA array and real-time PCR. Real-time PCR, western blotting and immunofluorescence were used to identify the expression profile of indicators related to fibrosis. Target gene of miR-4739 and promoter activity assay was measured by using dual-luciferase reporter assay system. In vivo, pleural fibrosis was evaluated by Masson staining and miR-4739 level was detected by In situ hybridization histochemistry. FINDINGS: We found that bleomycin induced up-regulation of miR-4739 in pleural mesothelial cells (PMCs). Over-regulated miR-4739 mediated mesothelial-mesenchymal transition and increased collagen-I synthesis in PMCs. Investigation on the clinical specimens revealed that high levels of miR-4739 and low levels of bone morphogenetic protein 7 (BMP-7) associated with pleural fibrosis in patients. Then we next identified that miR-4739 targeted and down-regulated BMP-7 which further resulted in unbalance between Smad1/5/9 and Smad2/3 signaling. Lastly, in vivo studies revealed that miR-4739 over-expression induced pleural fibrosis, and exogenous BMP-7 prevented pleural fibrosis in mice. INTERPRETATION: Our data indicated that miR-4739 targets BMP-7 which mediates pleural fibrosis. The miR-4739/BMP-7 axis is a promising therapeutic target for the disease. FUND: The National Natural Science Foundation of China.

Cigarette smoking aggravates bleomycin-induced experimental pulmonary fibrosis.

Idiopathic pulmonary fibrosis (IPF) is a chronic progressive lung disease that typically leads to respiratory failure and death. The cause of IPF is poorly understood. Although several environmental and occupational factors are considered as risk factors in IPF, cigarette smoking seems to be the most strongly associated risk factor. Here firstly, we treated mice with cigarette (16 mg tar, 1.0 mg nicotine in each cigarette) smoking and tried to explore the role of cigarette smoking in pulmonary fibrosis. Mice were continuously subjected to smoke for about 1 h each day (12 cigarettes per day, 5 days per week) during 40 days. Bleomycin was administrated by intraperitoneal injection at a dose of 40 mg/kg on days 1, 5, 8, 11 and 15. We found bleomycin induced pulmonary fibrosis in mice, and cigarette smoking augmented bleomycin-induced fibrosis reflected by both in fibrotic area and percentages of collagen in the lungs. Then we prepared and employed cigarette smoke extract (CSE) in cell models and found that CSE could induce the activation of p-Smad2/3 and p-Akt, as well as collagen-I synthesis and cell proliferation in lung fibroblasts and pleural mesothelial cells (PMCs). TGF-ß1 signaling mediated CSE-induced PMCs migration. Moreover, in vitro studies revealed that CSE had superimposed effect on bleomycin-induced activation of TGF-ß-Smad2/3 and -Akt signaling. TGF-ß-Smad2/3 and -Akt signaling were further augmented by cigarette smoking in the lung of bleomycin-treated mice. Taken together, these findings represent the first evidence that cigarette smoking aggravated bleomycin-induced pulmonary fibrosis via TGF-ß1 signaling.

A unique case report of endobronchial cryptococcosis and review of the literature.

Cryptococcosis is an infection caused by the yeast-like fungus Cryptococcus neoformans. Pulmonary cryptococcosis is typically identified as a single mass or as multiple nodules, while endobronchial lesions are quite rare. Here we report an uncommon case of pulmonary cryptococcosis presenting as endobronchial lesion in an immunocompetent patient. A 49-year-old male patient complained of intermittent cough with hemoptysis for two years. Computerized tomography of the chest showed a filling defect in the basal segment of the right lower lobe bronchus. A flexible bronchoscopic examination revealed a white smooth-surfaced polypoid lesion completely occluding the medial basal segment of the right lower lobe bronchus. The diagnosis was confirmed by bronchial biopsy under bronchoscopy, and the histopathologic findings showed the organisms were Cryptococcal neoformans. The patient was treated with fluconazole at a dose of 400 mg daily. The endobronchial lesion was found rapidly diminished after 18 days of therapy, and disappeared after 6.5 months of therapy by repeated fiberoptic bronchoscopy. Then the patient continued fluconazole for another 2.5 months. During the total 16 months' follow-up visits, the patient repeated CT scanning for five times, the results of which were all normal. The patient's symptoms disappeared as well, and now he is still under follow-up. This case highlights the fact that pulmonary cryptococcosis can present as endobronchial lesions even in immunocompetent subjects, mimicking lung tumor. Pathological confirmation is important to establish the definite diagnosis.

Medical thoracoscopy in China-the present status and the future.

Medical thoracoscopy (MT) refers to a minimally invasive procedure to inspect and perform a biopsy of the pleural space, as well as to perform therapeutic interventions, in a nonintubated patient under local anesthesia. This procedure provides the physician a window into the pleural space. Over the past two decades, MT has been developed very rapidly in China. We performed a review of the published data on MT in China, and estimated the present status, the challenges, and future perspectives of MT. From the data we conduct that MT is widely used well in China, not only in the diagnosis of exudative pleural effusions, but also in the management of pleural diseases, such as tuberculous pleural effusion, malignant pleural effusion and spontaneous pneumothorax. Meanwhile, it is noteworthy that few prospective clinical trials, lack of routine follow-up of MT are current domestic problems for diagnosis and management in pleural effusion. Consequently, more prospective, randomized clinical trials are needed to assess the diagnostic value and treatment superiorities of MT compared with traditional methods or other subjects in China in the future.