Yuta Hayashi

Attenuation of Transforming Growth Factor–β–Stimulated Collagen Production in Fibroblasts by Quercetin-Induced Heme Oxygenase–1

Quercetin is a flavonoid with a wide variety of cytoprotective and modulatory functions. Heme oxygenase-1 (HO-1) is an inducible enzyme. Its reaction product, carbon monoxide (CO), confers cellular protection in a number of conditions and diseases associated with oxidative or inflammatory lung injury. Furthermore, quercetin was reported to be a potent inducer of HO-1 in several cell types. We hypothesized that quercetin suppresses the production of collagen in fibroblasts via the induction of HO-1. Here, we showed that quercetin suppresses transforming growth factor-β (TGF-β)-induced collagen production in NIH3T3 cells and in normal human lung fibroblasts. This suppressive effect of quercetin was mediated by quercetin-induced HO-1. The suppression of collagen production was conferred by the reaction product of HO-1, CO, but not by bilirubin. Furthermore, the translocation of the nuclear factor E2-related factor-2 (Nrf2), an important transcription factor that regulates the expression of HO-1 from the cytoplasm to the nuclei, was demonstrated in NIH3T3 cells by exposure to quercetin. Assessment of the signal transduction pathway involved in TGF-β signaling showed that quercetin stimulated the Smad and mitogen-activated protein kinase pathway to varying degrees. Our results demonstrate that quercetin exerts suppressive effects on the expression of collagen by the induction of HO-1. Idiopathic pulmonary fibrosis is the most lethal diffuse fibrosing lung disease, and is characterized by the deposition of extracellular matrix. Given that HO-1 is one of the important molecules emerging as a central player in diseases, quercetin or its derivatives, which effectively induced HO-1, will lead to new therapeutic strategies for promoting antifibrotic therapy in respiratory diseases.

A catheter-type flow sensor for measurement of aspirated- and inspired-air characteristics in the bronchial region

We developed a novel catheter-type flow sensor for measuring the aspirated- and inspired-air characteristics trans-bronchially. An on-wall in-tube thermal flow sensor is mounted inside the tube, and it is used as a measurement tool in a bronchoscope. The external diameter of the tube is less than a few mm, and therefore, it can evaluate the flow characteristics in the small bronchial region. We newly developed a fabrication process to miniaturize it to less than 2.0 mm in the external diameter by using a heat shrinkable tube. A film sensor fabricated by photolithography was inserted into the tube by hand. By applying a heat shrinking process, the film was automatically mounted on the inner wall surface, and the outer size of the tube was miniaturized to almost half its original size. The final inner and outer diameters of the tube were 1.0 mm and 1.8 mm, respectively. The relationship between the input power of the sensor and the flow rate obeyed Kings equation in both forward and reverse flow conditions. The sensor output dependence on ambient temperature was also studied, and the curve obtained at 39.2 °C was used as the calibration curve in animal experiments. The sensor characteristics under reciprocating flow were studied by using a ventilator, and we confirmed that the sensor was able to measure the reciprocating flow at 2.0 Hz. Finally, we successfully measured the aspirated- and inspired-air characteristics in the air passage of a rat.

Quercetin protects against pulmonary oxidant stress via heme oxygenase-1 induction in lung epithelial cells.

The lung is a primary target for oxygen toxicity because of its constant exposure to high oxygen levels and environmental oxidants. Quercetin is one of the most commonly found dietary flavonoids, and it provides cytoprotective actions via activation of specific transcriptional factors and upregulation of endogenous defensive pathways. In the present study, we showed that quercetin increased the levels of heme oxygenase (HO)-1 expression and protected against hydrogen peroxide (H(2)O(2))-induced cytotoxicity in lung epithelial cell lines. Quercetin suppressed H(2)O(2)-induced apoptotic events, including hypodiploid cells, activation of caspase 3 enzyme activity and lactate dehydrogenase release. This cytoprotective effect was attenuated by the addition of the HO inhibitor, tin protoporphyrin IX. In addition, the end products of heme metabolites catalyzed by HO-1, carbon monoxide and bilirubin, protect against H(2)O(2)-induced cytotoxicity in LA-4 cells. Quercetin may well be one of the promising substances to attenuate oxidative epithelial cell injury in lung inflammation.

Erythromycin-induced CXCR4 expression on microvascular endothelial cells

Although stromal-derived factor-1 (SDF-1) via its cognate receptor CXCR4 is assumed to play a critical role in migration of endothelial cells during new vessel formation after tissue injury, CXCR4 expression on endothelial cells is strictly regulated. Erythromycin (EM), a 14-membered ring macrolide, has an anti-inflammatory effect that may account for its clinical benefit in the treatment of chronic inflammatory diseases. However, the effects of EM on endothelial cells and especially their expression of CXCR4 have not been fully evaluated. In this study, we demonstrated that EM markedly induced CXCR4 surface expression on microvascular endothelial cells in vitro and lung capillary endothelial cells in vivo. This ability to induce CXCR4 surface expression on endothelial cells was restricted to 14-membered ring macrolides and was not observed in other antibiotics including a 16-membered ring macrolide, josamycin. Furthermore, this EM-induced expression of CXCR4 on endothelial cells was functionally significant as demonstrated by chemotaxis assays in vitro. These findings suggest that EM-induced CXCR4 surface expression on endothelial cells may promote migration of CXCR4-expressing endothelial cells into sites of tissue injury, which may be associated with the known anti-inflammatory activity of this macrolide.

Up-regulation of surfactant protein production in a mouse model of secondary pulmonary alveolar proteinosis.

Although Pneumocystis infection might be one of the causes of secondary pulmonary alveolar proteinosis (PAP), the mechanism of its pathogenesis is uncertain. We analyzed a mouse model of secondary PAP resulting from Pneumocystis infection using mice deficient in CD40 (CD40KO), and evaluated the mechanism of the pathogenesis of secondary PAP from the viewpoint of surfactant-associated protein (SP) homeostasis, the overproduction of SP by type II alveolar epithelial cells, and the phagocytic function of alveolar macrophages (AMs). The effect of CD40 on SP production was also investigated in vitro using the H441 cell line, which has a phenotype similar to type II alveolar epithelial cells and primary alveolar epithelial cells. After long-term exposure to ovalbumin, CD40KO mice showed Pneumocystis infection and accumulation of surfactants in the alveoli (ApCD40KO). The amounts of SP production were up-regulated in ApCD40KO mice compared with wild-type mice treated using the same procedure. On the other hand, AMs from ApCD40KO mice did not show either phagocytic dysfunction or down-regulation of PU.1 expression. Furthermore, the stimulation of CD40-CD40 ligand (CD154) pathway regulated the production of SPs in H441 cells or primary alveolar epithelial cells. These results suggested that CD40KO mice could be one of the models useful for developing secondary PAP resulting from Pneumocystis infection. Surfactant accumulation was due to the overproduction in our model of secondary PAP. The CD40-CD154 interaction plays an important role in the regulation of surfactant-associated protein production.

Bronchial occlusion with Endobronchial Watanabe Spigots for massive hemoptysis in a patient with pulmonary Mycobacterium avium complex infection

The safety of occlusion with Endobronchial Watanabe Spigots (EWS) for the management of hemoptysis associated with chronic respiratory tract infection has not yet been established. A 57-year-old woman diagnosed as having pulmonary Mycobacterium avium complex (MAC) infection presented to our hospital with hemoptysis. She underwent bronchoscopy for bronchial occlusion with EWS, which resulted in the resolution of hemoptysis. Subsequently, she underwent bronchial artery embolization and then EWS were removed. During placement of EWS, no worsening of infection was observed. After removal of EWS, there was no recurrence of hemoptysis. Bronchial occlusion with EWS for hemoptysis associated with pulmonary MAC infection can be performed safely.

Catheter type of flow sensor for trans-bronchial measurement forlung functions

We propose a novel catheter type of flow sensor as a tool for trans-bronchial measurement. An on-wall in-tube thermal flow sensor is mounted on the inside of a tube, and it is used as a diagnostic tool in a bronchoscope. The external diameter of the tube is less than a few mm, and therefore, it can evaluate the flow characteristics in the bronchiole. The relationship between the input power of the sensor and the flow rate obeyed Kings equation. The sensor output dependence on ambient temperature was also studied, and the curve obtained at 39.2 °C was used as the calibration curve in animal experiments. The sensor characteristics under reciprocating flow were studied by using a ventilator, and we confirmed that the sensor was able to measure the reciprocating flow at of 2.0 Hz. Finally, we successfully measured the inspired and expired air characteristics in rats in vivo.

Clinico-microbiological analysis of 121 patients with pulmonary Mycobacteroides abscessus complex disease in Japan – An NTM-JRC study with RIT

RATIONALE No comprehensive analysis has previously been performed to evaluate the clinical aspects of and microbiological evidence associated with Mycobacteroides abscessus complex (MABC) infection in a region, such as Japan, with a low MABC incidence. OBJECTIVES This study aimed to clarify the clinicopathological characteristics of MABC, which included clinical relatedness to erm(41) sequevar, phenotype (as colony morphology and minimum inhibitory concentration), and genotype. METHODS A total of 121 MABC patients (68 with M. abscessus subsp. abscessus and 53 with M. abscessus subsp. massiliense) were recruited into this retrospective clinical-biological study from tertiary hospitals in Japan between 2004 and 2014. RESULTS Approximately 30% of MABC patients had a history of previous nontuberculous mycobacterium (NTM) disease. Furthermore, 24.8% of the patients had another concomitant NTM infection after they were diagnosed with MABC. Fewer than 10% of the patients in the M. abscessus group had T28C in erm(41). While we observed a higher conversion rate for M. massiliense than for M. abscessus (72.4% and 34.8%, respectively, p = 0.002), recurrence remained relatively common for M. massiliense (31.0%). In the M. abscessus patients, the MIC of clarithromycin (CLR) was significantly lower on day 3 in patients with a better treatment response than in refractory patients (The median MIC; 0.75 μg/ml v.s 2.0 μg/ml, p = 0.03). There was no significant relation between clinical manifestations and variable number of tandem repeat genotypes. CONCLUSIONS Because the history and simultaneous isolation of other NTM in MABC infection are relatively common, these information should be carefully translated into clinical actions. The evaluation of early CLR resistance in M. abscessus and the erm(41) functions should be important to improve the treatment strategy.