Deletion of tetraspanin CD9 diminishes lymphangiogenesis in vivo and in vitro.

Tetraspanins have emerged as key players in malignancy and inflammatory diseases, yet little is known about their roles in angiogenesis, and nothing is known about their involvement in lymphangiogenesis. We found here that tetraspanins are abundantly expressed in human lymphatic endothelial cells (LEC). After intrathoracic tumor implantation, metastasis to lymph nodes was diminished and accompanied by decreased angiogenesis and lymphangiogenesis in tetraspanin CD9-KO mice. Moreover, lymphangiomas induced in CD9-KO mice were less pronounced with decreased lymphangiogenesis compared with those in wild-type mice. Although mouse LEC isolated from CD9-KO mice showed normal adhesion, lymphangiogenesis was markedly impaired in several assays (migration, proliferation, and cable formation) in vitro and in the lymphatic ring assay ex vivo. Consistent with these findings in mouse LEC, knocking down CD9 in human LEC also produced decreased migration, proliferation, and cable formation. Immunoprecipitation analysis demonstrated that deletion of CD9 in LEC diminished formation of functional complexes between VEGF receptor-3 and integrins (α5 and α9). Therefore, knocking down CD9 in LEC attenuated VEGF receptor-3 signaling, as well as downstream signaling such as Erk and p38 upon VEGF-C stimulation. Finally, double deletion of CD9/CD81 in mice caused abnormal development of lymphatic vasculature in the trachea and diaphragm, suggesting that CD9 and a closely related tetraspanin CD81 coordinately play an essential role in physiological lymphangiogenesis. In conclusion, tetraspanin CD9 modulates molecular organization of integrins in LEC, thereby supporting several functions required for lymphangiogenesis.

Validation of noninvasive morphological and diffusion imaging in mouse emphysema by micro-computed tomography and hyperpolarized (129)Xe magnetic resonance imaging.

Animal disease models are pivotal in investigating the pathogenesis of emphysema and developing novel drugs, but the modalities to evaluate murine emphysema models have been of limited validity and sensitivity. In this study, we evaluated hyperpolarized (129)Xe magnetic resonance imaging (MRI) and micro-computed tomography (micro-CT) compared with traditional methods, such as plethysmography and histology. Elastase-treated mice and adiponectin knockout mice were used as murine emphysema models to evaluate these modalities. Three weeks after elastase administration, significant and heterogeneous emphysema was evaluated according to the mean linear intercept and plethysmography parameters. Notably, the distribution of low-density areas, as examined by micro-CT, correlated with the mean linear intercept and plethysmography parameters in whole lungs. These correlations were also observed in regional areas. Furthermore, we introduced hyperpolarized (129)Xe MRI, which can evaluate gas exchange between the alveoli and blood during spontaneous breathing. Parameters of gas exchange (fD) and alveolar size (Vs/Va) were significantly decreased in elastase-treated mice, and moderately correlated with the plethysmography parameters. Of importance, we could detect a decrease of the fD value in low-density areas with micro-CT, suggesting that gas exchange decreased in emphysematous lesions. Likewise, these parameters (fD and Vs/Va) were also decreased in adiponectin knockout mice, which exhibit emphysema with a homogeneous distribution. We demonstrated the feasibility of (129)Xe MRI and micro-CT in combination with traditional modalities. These noninvasive modalities provide complementary data that can be used for repeated estimations of regional gas exchange and lung morphology.

Tetraspanin CD151 protects against pulmonary fibrosis by maintaining epithelial integrity.

RATIONALE: Idiopathic pulmonary fibrosis (IPF) is a chronic pulmonary disorder of unknown etiology with few treatment options. Although tetraspanins are involved in various diseases, their roles in fibrosis have not been determined. OBJECTIVES: To investigate the role of tetraspanin CD151 in pulmonary fibrosis. METHODS: CD151 knockout (KO) mice were studied by histological, biochemical, and physiological analyses and compared with wild-type mice and CD9 KO mice. Further mechanistic analyses were performed in vitro, in vivo, and on samples from patients with IPF. MEASUREMENTS AND MAIN RESULTS: A microarray study identified an enrichment of genes involved in connective tissue disorders in the lungs of CD151 KO mice, but not in CD9 KO mice. Consistent with this, CD151 KO mice spontaneously exhibited age-related pulmonary fibrosis. Deletion of CD151 did not affect pulmonary fibroblast functions but instead degraded epithelial integrity via attenuated adhesion strength on the basement membrane; CD151-deleted alveolar epithelial cells exhibited increased α-SMA expression with activation of p-Smad2, leading to fibrotic changes in the lungs. This loss of epithelial integrity in CD151 KO lungs was further exacerbated by intratracheal bleomycin exposure, resulting in severe fibrosis with increased mortality. We also observed decreased numbers of CD151-positive alveolar epithelial cells in patients with IPF. CONCLUSIONS: CD151 is essential for normal function of alveolar epithelial cells; loss of CD151 causes pulmonary fibrosis as a result of epithelial disintegrity. Given that CD151 may protect against fibrosis, this protein represents a novel target for the treatment of fibrotic diseases.

Involvement of endothelial apoptosis underlying chronic obstructive pulmonary disease-like phenotype in adiponectin-null mice: implications for therapy.

RATIONALE: Chronic obstructive pulmonary disease is frequently complicated with comorbidities, such as cardiovascular disease, osteoporosis, and body weight loss, but the causal link remains unclear. OBJECTIVES: To investigate the role of adiponectin in the pathogenesis of chronic obstructive pulmonary disease and its potential use in therapy. METHODS: Adiponectin localization and dynamics in the lung were analyzed in an elastase-induced emphysema model. Next, the lung of adiponectin-knockout mice, extrapulmonary effects, and the underlying mechanism were investigated. Finally, we tested whether exogenous adiponectin could ameliorate the emphysematous change in adiponectin-knockout mice. MEASUREMENTS AND MAIN RESULTS: Adiponectin expression in lung vasculature and plasma concentration of adiponectin were reduced after elastase-instillation. Notably, adiponectin-knockout mice showed progressive alveolar enlargement and increased lung compliance. They further exhibited not only systemic inflammation, but also extrapulmonary phenotype, such as body weight loss, fat atrophy, and osteoporosis. Moreover, endothelial apoptosis was enhanced in the lungs of adiponectin-knockout mice, as evidenced by caspase-3 activity. Consistent with this, expressions of vascular endothelial growth factor receptor-2 and platelet endothelial cell adhesion molecule-1 on endothelial cells were decreased in the adiponectin-knockout mice. Finally, adenovirus-mediated adiponectin supplementation ameliorated the emphysematous phenotype. CONCLUSIONS: Adiponectin-knockout mice develop progressive chronic obstructive pulmonary disease-like phenotype with systemic inflammation and extrapulmonary phenotypes. Hypoadiponectinemia could thus play a critical role in the progression of chronic obstructive pulmonary disease and concomitant comorbidities through endothelial dysfunction. Together, adiponectin could be a novel target for chronic obstructive pulmonary disease therapy.

Tetraspanin CD9 negatively regulates lipopolysaccharide-induced macrophage activation and lung inflammation.

Tetraspanins facilitate the formation of multiple molecular complexes at specialized membrane microdomains and regulate cell activation and motility. In the present study, the role of tetraspanin CD9 in LPS-induced macrophage activation and lung inflammation was investigated in vitro and in vivo. When CD9 function was ablated with mAb treatment, small interfering RNA transfection, or gene knockout in RAW264.7 cells or bone marrow-derived macrophages, these macrophages produced larger amounts of TNF-alpha, matrix metalloproteinase-2, and -9 upon stimulation with LPS in vitro, when compared with control cells. Sucrose gradient analysis revealed that CD9 partly colocalized with the LPS-induced signaling mediator, CD14, at low-density light membrane fractions. In CD9 knockout macrophages, CD14 expression, CD14 and TLR4 localization into the lipid raft, and their complex formation were increased whereas IkappaBalpha expression was decreased when compared with wild-type cells, suggesting that CD9 prevents the formation of LPS receptor complex. Finally, deletion of CD9 in mice enhanced macrophage infiltration and TNF-alpha production in the lung after intranasal administration of LPS in vivo, when compared with wild-type mice. These results suggest that macrophage CD9 negatively regulates LPS response at lipid-enriched membrane microdomains.

[A case of lung adenocarcinoma effectively treated with sivelestat and corcicosteroid for drug-induced lung disease due to gefitinib].

A 70-year-old Japanese man was re-admitted because of relapse of adenocarcinoma of the lung. He received daily administration of gefitinib as second-line chemotherapy. He was given a diagnosis of drug-induced lung disease due to gefitinib on day 6 because of hypoxemia and ground glass opacities in the bilateral lung fields. There was no response to corticosteroid pulse therapy. Continuous administration of sivelestat was intravenously added from day 9. Although mechanical ventilation was required for 10 days, lung infiltrates and hypoxia gradually improved. Sivelestat and corcicosteroid was apparently effective in this case and may be useful treatment for drug-induced lung disease due to gefitinib.

Double deletion of tetraspanins CD9 and CD81 in mice leads to a syndrome resembling accelerated aging.

Chronic obstructive pulmonary disease (COPD) has been recently characterized as a disease of accelerated lung aging, but the mechanism remains unclear. Tetraspanins have emerged as key players in malignancy and inflammatory diseases. Here, we found that CD9/CD81 double knockout (DKO) mice with a COPD-like phenotype progressively developed a syndrome resembling human aging, including cataracts, hair loss, and atrophy of various organs, including thymus, muscle, and testis, resulting in shorter survival than wild-type (WT) mice. Consistent with this, DNA microarray analysis of DKO mouse lungs revealed differential expression of genes involved in cell death, inflammation, and the sirtuin-1 (SIRT1) pathway. Accordingly, expression of SIRT1 was reduced in DKO mouse lungs. Importantly, siRNA knockdown of CD9 and CD81 in lung epithelial cells additively decreased SIRT1 and Foxo3a expression, but reciprocally upregulated the expression of p21 and p53, leading to reduced cell proliferation and elevated apoptosis. Furthermore, deletion of these tetraspanins increased the expression of pro-inflammatory genes and IL-8. Hence, CD9 and CD81 might coordinately prevent senescence and inflammation, partly by maintaining SIRT1 expression. Altogether, CD9/CD81 DKO mice represent a novel model for both COPD and accelerated senescence.

[A case of spontaneous resolution of sarcoidosis with primary pulmonary cavitations].

On routine physical checkup, a 27-year-old man with productive cough was found to have multiple nodules with cavitation in the bilateral lung fields and mediastinal and hilar lymph adenopathy on chest X-ray film and CT scan. Serum levels of angiotensin converting enzyme and lysozyme were high. Tuberculin reaction was negative. Non-caseous epitheloid granulomas were confirmed in the bronchial wall specimens obtained by trans-bronchial biopsy. The number of lymphocytes and the CD4/CD8 ratio of lymphocytes in bronchoalveolar lavage fluid was increased. Therefore, pulmonary sarcoidosis was diagnosed, and the lung nodules with cavitation were considered due to sarcoidosis. The walls of the cavitations gradually thinned and had almost completely vanished after 6 months of careful observation without steroid therapy.

[A case of pneumonitis suspected to be induced by Oseltamivir].

A 33-year-old man had a high fever and was given Cefcapene and Oseltamivir without a definite diagnosis of influenza. Three days later an abnormal chest shadow was pointed out. Chest CT revealed ground-glass opacities and air-space consolidation in bilateral lung fields. Although he was given antibiotics, lung infiltrates increased and his symptoms worsened. Therefore, he was transferred to our hospital. Corticosteroid pulse-therapy resulted in prompt improvement of chest infiltrates and his symptoms. The drug-induced lymphocyte stimulating test results indicated 170% of oseltamivir and 150% of cefcapene. Considering the clinical course and laboratory data, this was probably drug-induced lung injury caused by oseltamivir.

[Case of lung cancer with chylothorax].

A 42-year-old man had swelling in the right side of the neck, cough and chest pain. On admission, an abnormal shadow was detected in the right upper lung field and squamous cell carcinoma of the lung with superior vena cava (SVC) syndrome was diagnosed. Concurrent radiotherapy and systemic chemotherapy consisting of cisplatin and vinorelbine induced a partial response. At 15 months after diagnosis, he was re-admitted because of bilateral pleural effusion and facial edema due to relapse of SVC syndrome. Examination of the milky right pleural effusion revealed chylothorax (959mg/dl of beta-lipoprotein and 675mg/dl of triglyceride). The right effusion was finally controlled by pleurodesis with OK-432. Non-traumatic chylothorax is a rare complication of lung cancer.

Simultaneous bilateral spontaneous pneumothorax observed during the administration of gefitinib for lung adenocarcinoma with multiple lung metastases.

A 41-year-old man with productive cough was admitted to our hospital. His chest roentgenogram showed multiple small nodules in the bilateral lung fields. The nodules were revealed as intrapulmonary metastases of the adenocarcinoma of the lung. Systemic chemotherapy with paclitaxel and carboplatin was not effective, and continuous oral gefitinib therapy was initiated. Twenty-one days later, spontaneous pneumothorax was found in the left lung, and four days after that, in the right lung as well. The extent of the pneumothorax was slight; therefore, he recovered without drainage within several days. Spontaneous pneumothorax, especially bilateral pneumothorax, is a rare complication of chemotherapy for lung cancer.

[A case of lung cancer with cranial neuropathy as the first sign of onset due to metastatic leptomeningeal carcinomatosis].

A 68-year-old man suffered right facial palsy and left deafness, however, his condition was considered to be idiopathic and he was followed. Three months later, bloody sputum and hoarseness caused him to be admitted to our hospital. An abnormal shadow was detected in the right upper lung field and adenocarcinoma of the lung with multiple brain metastases was diagnosed. He underwent gamma-knife radiosurgery for the brain lesions and subsequent systemic chemotherapy consisting of combined carboplatin and paclitaxel, which were not effective. Subsequently various neurological symptoms appeared, such as muscle weakness of the extremities, dizziness, and gait disturbance. Adenocarcinoma cells confirmed in the cerebrospinal fluid were similar to those in the obtained by transbronchial curetting. Whole-brain irradiation was performed, however, the neurological symptoms worsened and he died. Leptomeningeal carcinomatosis is difficult to diagnose while the patient is alive. It is thought that cranial neuropathy due to leptomeningeal carcinomatosis is a rare form of onset for lung cancer.

Gefitinib in patients with brain metastases from non-small-cell lung cancer: review of 15 clinical cases.

The clinical efficacy of gefitinib, a tyrosine kinase inhibitor of epidermal growth factor receptor (EGFR), on brain metastases (BMs) from non-small-cell lung cancer (NSCLC) was evaluated. Fifteen patients with recurrent NSCLC with metastasis to the brain were treated with gefitinib. The objective tumor response rate (60%; 9 of 15 patients) for BM was the same as for primary tumors. The median time to response of BM was 26 days. In 8 of 9 patients who exhibited partial response in the thoracic lesion, BM showed dramatic regression, including 1 complete response. One patient with stable primary tumor also exhibited partial response in BM with this monotherapy. Brain metastasis-related neurologic symptoms such as hemiparesis, dysarthria, dysphagia, and vertigo improved or disappeared with the objective response of BM as confirmed by magnetic resonance imaging. Central nervous system toxicities were not observed during the treatment. Four of the 9 BM responders are still under treatment with neither adverse events nor disease progression. Two discontinued the treatment because of severe hepatic toxicity and 3 died because of acquired resistance in pulmonary lesions, even though partial response was observed in the BMs. Finally, median duration of response of BM was 8.7 months and median overall survival was 8.3 months (range, 1.8 to > 15.7 months). Molecular targeted therapy against EGFR could be an option for the treatment of BM from NSCLC refractory to conventional chemotherapy plus radiation therapy because it has demonstrated a distinct therapeutic potential against BM compared with primary lung tumor and extracranial metastases.

Statins decrease lung inflammation in mice by upregulating tetraspanin CD9 in macrophages.

Tetraspanins organize protein complexes in tetraspanin-enriched membrane microdomains that are distinct from lipid rafts. Our previous studies suggested that reduction in the levels of tetraspanins CD9 and CD81 may be involved in the progression of inflammatory lung diseases, especially COPD. To search for agents that increase the levels of these tetraspanins, we screened 1,165 drugs in clinical use and found that statins upregulate CD9 and CD81 in RAW264.7 macrophages. The lipophilic statins, fluvastatin and simvastatin, reversed LPS-induced downregulation of CD9 and CD81, simultaneously preventing TNF-α and matrix metalloproteinase-9 production and spreading of RAW264.7 cells. These statins exerted anti-inflammatory effects in vitro in wild-type macrophages but not in CD9 knockout macrophages, and decreased lung inflammation in vivo in wild-type mice but not in CD9 knockout mice, suggesting that their effects are dependent on CD9. Mechanistically, the statins promoted reverse transfer of the LPS-signaling mediator CD14 from lipid rafts into CD9-enriched microdomains, thereby preventing LPS receptor formation. Finally, upregulation of CD9/CD81 by statins was related to blockade of GTPase geranylgeranylation in the mevalonate pathway. Our data underscore the importance of the negative regulator CD9 in lung inflammation, and suggest that statins exert anti-inflammatory effects by upregulating tetraspanin CD9 in macrophages.

Double deficiency of tetraspanins CD9 and CD81 alters cell motility and protease production of macrophages and causes chronic obstructive pulmonary disease-like phenotype in mice.

CD9 and CD81 are closely related tetraspanins that regulate cell motility and signaling by facilitating the organization of multimolecular membrane complexes, including integrins. We show that CD9 and CD81 are down-regulated in smoking-related inflammatory response of a macrophage line, RAW264.7. When functions of CD9 and CD81 were ablated with monoclonal antibody treatment, small interfering RNA transfection, or gene knock-out, macrophages were less motile and produced larger amounts of matrix metalloproteinase (MMP)-2 and MMP-9 than control cells in vitro. In line with this, CD9/CD81 double-knock-out mice spontaneously developed pulmonary emphysema, a major pathological component of chronic obstructive pulmonary disease (COPD). The mutant lung contained an increased number of alveolar macrophages with elevated activities of MMP-2 and MMP-9 and progressively displayed enlarged airspace and disruption of elastic fibers in the alveoli. Secretory cell metaplasia, a finding similar to goblet cell metaplasia in cigarette smokers, was also observed in the epithelium of terminal bronchioles. With aging, the double-knockout mice showed extrapulmonary phenotypes, including weight loss, kyphosis, and osteopenia. These results suggest that the tetraspanins CD9 and CD81 regulate cell motility and protease production of macrophages and that their dysfunction may underlie the progression of COPD.