Takeshi Hisada

Resolvin E1 dampens airway inflammation and hyperresponsiveness in a murine model of asthma.

Resolvin E1 (RvE1; 5S, 12R, 18R-trihydroxyeicosapentaenoic acid) is an anti-inflammatory lipid mediator derived from the omega-3 fatty acid eicosapentaenoic acid (EPA). It has been recently shown that RvE1 is involved in the resolution of inflammation. However, it is not known whether RvE1 is involved in the resolution of asthmatic inflammation. To investigate the anti-inflammatory effect of RvE1 in asthma, a murine model of asthma was studied. After RvE1 was administered to mice intraperitoneally, there were decreases in: airway eosinophil and lymphocyte recruitment, specific Th2 cytokine, IL-13, ovalbumin-specific IgE, and airway hyperresponsiveness (AHR) to inhaled methacholine. Moreover, RvE1-treated mice had significantly lower mucus scores compared to vehicle-treated mice based on the number of goblet cells stained with periodic acid-schiff (PAS). These findings provide evidence that RvE1 is a pivotal counterregulatory signal in allergic inflammation and offer novel multi-pronged therapeutic approaches for human asthma.

l-type amino acid transporter 1 and CD98 expression in primary and metastatic sites of human neoplasms.

The significance of l‐type amino acid transporter (LAT) 1 expression remains unclear in the metastatic process of human neoplasms, whereas experimental studies have demonstrated that LAT1 is associated with the metastatic process of cancer cells. We compared the immunohistochemical expression of LAT1 and CD98 between the primary site and a concordant pulmonary metastatic site in 93 cancer patients, all of whom had undergone thoracotomy. LAT1, CD98, Ki‐67 labeling index, vascular endothelial growth factor (VEGF), CD31, and CD34 were analyzed by immunohistochemical staining in the resected tumors of 93 cancer patients: 45 colon cancers; nine breast cancers; eight head and neck cancers; 11 genital cancers; 14 soft‐tissue sarcomas; and six other cancers. The expression of these markers was significantly higher in the metastatic sites than in the primary sites. In total, the positive rates of LAT1, CD98, Ki‐67, VEGF, CD31, and CD34 were 40, 24, 56, 41, 45, and 39%, respectively, in the primary sites and 65, 45, 84, 67, 73, and 61%, respectively, in the metastatic sites. LAT1 expression was closely correlated with CD98 expression, angiogenesis, and cell proliferation. The association between LAT1 and CD98 expression was strongest in the primary and metastatic sites. The present study suggests that overexpression of LAT1 and CD98 has an important role to play in the metastatic process of variable human neoplasms. Moreover, LAT1 expression was significantly correlated with cell proliferation and angiogenesis. (Cancer Sci 2008; 99: 2380–2386)

Fluorine-18-α-Methyltyrosine Positron Emission Tomography for Diagnosis and Staging of Lung Cancer: A Clinicopathologic Study

Purpose:l-[3-18F]-α-Methyltyrosine ([18F]FMT) is an amino acid tracer for positron emission tomography (PET). We evaluated the diagnostic usefulness of [18F]FMT PET in non–small-cell lung cancer (NSCLC) patients. Tumor uptake of [18F]FMT was compared with that of 2-[18F]-fluoro-2-deoxy-d-glucose ([18F]FDG) and correlated with L-type amino acid transporter 1 (LAT1) expression. Experimental Design: Fifty NSCLC patients were enrolled in this study, and a pair of PET study with [18F]FMT and [18F]FDG was done. LAT1 expression and Ki-67 labeling index of the resected tumors were analyzed by immunohistochemical staining. Results: For the primary tumor detection, [18F]FMT PET exhibited a sensitivity of 90% whereas the sensitivity for [18F]FDG PET was 94%. For lymph node staging, the sensitivity and specificity of [18F]FMT PET were 57.8% and 100%, and those of [18F]FDG PET were 65.7% and 91%, respectively. The expression of LAT1 in squamous cell carcinoma and large cell carcinoma was significantly higher than that in adenocarcinoma. [18F]FMT uptake was also higher in squamous cell carcinoma and large cell carcinoma than in adenocarcinoma. Uptake of [18F]FMT in the tumor is closely correlated with LAT1 expression (ρ = 0.890). Conclusion: [18F]FMT PET had no false-positives in the detection of primary tumor and lymph node metastasis and could improve the diagnostic performance in NSCLC. Uptake of [18F]FMT correlated with the expression of LAT1 that showed a significant association with cellular proliferation.

Prognostic significance of L-type amino acid transporter 1 (LAT1) and 4F2 heavy chain (CD98) expression in stage I pulmonary adenocarcinoma

BACKGROUND The purpose of this study was to evaluate the prognostic value of l-type amino acid transporter 1 (LAT1) and 4F2 heavy chain (CD98) expression in patients with stage I pulmonary adenocarcinoma. METHODS A total of 139 consecutive patients with pathologic stage I pulmonary adenocarcinoma were retrospectively reviewed. Expression of LAT1, CD98, Ki-67 labeling index, vascular endothelial growth factor (VEGF) and microvessel density (MVD) was also evaluated immunohistochemically and correlated with the prognosis of patients after complete resection of the tumor. RESULTS LAT1 and CD98 expression were positive in 23% (32/139) and 22% (31/139), respectively (p=0.887). LAT1 with CD98 expression was recognized in 15% (21/139). LAT1 expression was significantly correlated with CD98, Ki-67 labeling index, VEGF, and MVD. The 5-year survival rates of LAT1-positive and -negative patients and CD98-positive and -negative patients, were 60.2 and 95.2% (p<0.0001) and 72.5 and 93.4% (p=0.0008), respectively. Univariate analysis disclosed that cellular proliferation and MVD in the tumor were significant prognostic factors. However, multivariate analysis confirmed that positive expression of LAT1 and CD98 was an independent factor for predicting a poor prognosis. CONCLUSION The overexpression of LAT1 and CD98 is a pathological factor to predict the prognosis in patients with resectable stage I pulmonary adenocarcinoma.

Atrial natriuretic peptide inhibits tumor necrosis factor-alpha production by interferon-gamma-activated macrophages via suppression of p38 mitogen-activated protein kinase and nuclear factor-kappa B activation.

We investigated whether the atrial natriuretic peptide (ANP) might have an inhibitory effect on inflammatory cells. Treatment of RAW264.7 macrophages with interferon-gamma (IFN- gamma) caused a significant increase in tumor necrosis factor-alpha (TNF-alpha) and nitric oxide (NO) production. Activation of p38 mitogen-activated protein (MAP) kinase was observed 30 to 120 min after IFN-gamma, and transcription factor nuclear factor-kappa B (NF-kappaB) was activated about 7 to 9 times of the basal activity. Human ANP(99-126) and a specific p38 MAP kinase inhibitor SB203580 inhibited the IFN-gamma-induced TNF-alpha production in a dose-dependent manner without affecting NO production. ANP inhibited the IFN-gamma-induced p38 MAP kinase activation, and ANP and SB203580 inhibited NF-kappaB activation. To study the involvement of oxidative stress in this system, the effects of allopurinol and acetovanillone, inhibitors of xanthine oxidase and NADPH oxidase, respectively, were studied. Allopurinol or acetovanillone did not inhibit the IFN-gamma-induced production of TNF-alpha or NO, suggesting little involvement of oxidative stress in this system. This is the first evidence in vitro that ANP has an anti-inflammatory activity on IFN-gamma-activated macrophages by suppressing signal transduction pathway leading to p38 MAP kinase and NF-kappaB activation.

Protective effect of resolvin E1 on the development of asthmatic airway inflammation.

Resolvin E1 (RvE1) is an anti-inflammatory lipid mediator derived from the omega-3 fatty acid eicosapentaenoic acid (EPA), and strongly acts in the resolution of inflammation. We previously reported that RvE1 dampens airway inflammation and hyperresponsiveness in a murine model of asthma. In the present study, to elucidate the effects of RvE1 on the development of asthmatic airway inflammation, we investigated whether RvE1 acts on different phases of an OVA-sensitized and -challenged mouse model of asthma. RvE1 treatments at the time of either OVA sensitization or at the time of OVA challenge were investigated and compared with RvE1 treatments at the time of both OVA sensitization and challenge. After RvE1 was administered to mice intraperitoneally at the time of both OVA sensitization and challenge, there were decreases in airway eosinophil and lymphocyte recruitment, as well as a reduction in Th2 cytokine and airway hyperresponsiveness. RvE1 treatment at the time of either OVA sensitization or challenge also improved AHR and airway inflammation. Our results suggest that RvE1 acts on several phases of asthmatic inflammation and may have anti-inflammatory effects on various cell types.

Extracellular acidification stimulates IL-6 production and Ca2+ mobilization through proton-sensing OGR1 receptors in human airway smooth muscle cells

The asthmatic airway has been shown to be an acidic environment that may be involved in the pathophysiological features of asthma. However, the mechanism by which an acidic pH modulates the cellular activities involved in the asthmatic airway remains elusive. Here, we characterized acidic pH-induced actions in human airway smooth muscle cells (ASMCs). Extracellular acidification stimulates the mRNA expression and protein production of IL-6, a proinflammatory cytokine, in association with the phosphorylation of extracellular signal-regulated kinase (ERK) and p38MAPK, reflecting the activation of the enzymes. Acidification-induced cytokine production was inhibited by inhibitors of ERK and p38MAPK. Acidification also increased intracellular Ca(2+) concentration, which was accompanied by cell rounding, most likely reflecting contraction. In ASMCs, OGR1 is expressed at by far the highest levels among proton-sensing G protein-coupled receptors. The knockdown of OGR1 and G(q/11) protein with their specific small interfering RNAs and an inhibition of G(q/11) protein with YM-254890 attenuated the acidification-induced actions. We conclude that extracellular acidification stimulates IL-6 production and Ca(2+) mobilization through proton-sensing OGR1 receptors/G(q/11) proteins in human ASMCs.

Correlation of angiogenesis with 18F-FMT and 18F-FDG uptake in non-small cell lung cancer

L‐[3‐18F]‐α‐methyltyrosine (18F‐FMT) is an amino‐acid tracer for positron‐emission tomography (PET). We have conducted a clinicopathologic study to elucidate the correlation of angiogenesis with 18F‐FMT and 2‐[18F]‐fluoro‐2‐deoxy‐D‐glucose (18F‐FDG) uptake in patients with non‐small cell lung cancer (NSCLC). Thirty‐seven NSCLC patients were enrolled in this study, and two PET studies with 18F‐FMT and 18F‐FDG were performed. Uptake of PET tracers was evaluated with standardized uptake value. Vascular endothelial growth factor (VEGF), CD31, CD34, L‐type amino acid transporter 1 (LAT1) and Ki‐67 labeling index of the resected tumors were analyzed by immunohistochemical staining, and correlated with the clinicopathologic variables and the uptake of PET tracers. The median VEGF rate was 45% (range, 10–78%). High expression was seen in 30 patients (81%, 30/37). VEGF expression was statistically associated with progressively growing microvessel count. VEGF showed a correlation with LAT1 expression (P = 0.04) and Ki‐67 labeling index (P = 0.01). However, it showed no correlation with age, gender, disease stage, tumor size, and histology. Microvessel density (MVD) showed no correlation with any parameters. 18F‐FMT and 18F‐FDG uptake correlated significantly with VEGF (P < 0.0001, P = 0.026, respectively), whereas the correlation of 18F‐FMT and VEGF was more meaningful. The present study demonstrated that the metabolic activity of primary tumors as evaluated by PET study with 18F‐FMT and 18F‐FDG is related to tumor angiogenesis and the proliferative activity in NSCLC. (Cancer Sci 2009; 100: 753–758)

Mechanism of gastroesophageal reflux in patients with obstructive sleep apnea syndrome.

Background  It has been reported that the prevalence of gastroesophageal reflux (GER) disease is high in patients with obstructive sleep apnea (OSA). End‐inspiratory intra‐esophageal pressure decreases progressively during OSA, which has been thought to facilitate GER in OSA patients. The aim of our study was to clarify the mechanisms of GER during sleep (sleep‐GER) in OSA patients.

PI3K p110β Positively Regulates Lipopolysaccharide-Induced IL-12 Production in Human Macrophages and Dendritic Cells and JNK1 Plays a Novel Role

The PI3K family is thought to participate in TLR signaling, and it has been reported to be a negative regulator of TLR-mediated production of IL-12, a key inducer of Th1 responses. However, the role of individual PI3K subtypes in IL-12 production remains obscure. We defined the distinct regulation of LPS-mediated IL-12 production by p110α and p110β catalytic subunits of PI3K in human APCs. We observed that knockdown of PI3K p110β by small interfering RNA (siRNA) suppressed both LPS-induced IL-12 protein production and mRNA expression in monocyte-derived macrophages and dendritic cells (DCs). Knockdown of PI3K p110α by siRNA reduced LPS-induced IL-12 protein production in both cell types. Conversely, knockdown of PI3K p110α suppressed LPS-induced IL-12 mRNA expression in monocyte-derived macrophages but minimally affected monocyte-derived DCs. PI3K p110β siRNA inhibited JNK activation, but not p38 MAPK or ERK activation, stimulated by LPS, while PI3K p110α siRNA did not affect LPS-induced JNK, p38 MAPK, or ERK activation in both cell types. Transfection of siRNA against JNK1, JNK2, and both decreased LPS-induced IL-12 production. Furthermore, PI3K p110β siRNA attenuated LPS-induced JNK1 phosphorylation, while not affecting JNK2 phosphorylation. Our findings indicate that PI3K p110β positively controls LPS-induced IL-12 production through the JNK1-dependent pathway in human macrophages and DCs.