Masakiyo Yatomi

Extracellular acidification induces connective tissue growth factor production through proton-sensing receptor OGR1 in human airway smooth muscle cells

Asthma is characterized by airway inflammation, hyper-responsiveness and remodeling. Extracellular acidification is known to be associated with severe asthma; however, the role of extracellular acidification in airway remodeling remains elusive. In the present study, the effects of acidification on the expression of connective tissue growth factor (CTGF), a critical factor involved in the formation of extracellular matrix proteins and hence airway remodeling, were examined in human airway smooth muscle cells (ASMCs). Acidic pH alone induced a substantial production of CTGF, and enhanced transforming growth factor (TGF)-β-induced CTGF mRNA and protein expression. The extracellular acidic pH-induced effects were inhibited by knockdown of a proton-sensing ovarian cancer G-protein-coupled receptor (OGR1) with its specific small interfering RNA and by addition of the G(q/11) protein-specific inhibitor, YM-254890, or the inositol-1,4,5-trisphosphate (IP(3)) receptor antagonist, 2-APB. In conclusion, extracellular acidification induces CTGF production through the OGR1/G(q/11) protein and inositol-1,4,5-trisphosphate-induced Ca(2+) mobilization in human ASMCs.

17(R)‐resolvin D1 ameliorates bleomycin‐induced pulmonary fibrosis in mice

Idiopathic pulmonary fibrosis (IPF) is a destructive inflammatory disease with limited therapeutic options. Inflammation plays an integral role in the development of pulmonary fibrosis. Unresolved inflammatory responses can lead to substantial tissue injury, chronic inflammation, and fibrosis. The resolvins are a family of endogenous ω‐3 fatty acid derived‐lipid mediators of inflammation resolution. Resolvin D1 (RvD1) displays potent anti‐inflammatory, pro‐resolving activity, without causing immunosuppression. Its epimer, 17(R)‐resolvin D1 (17(R)‐RvD1), exhibits equivalent functionality to RvD1. In addition, 17(R)‐RvD1 is resistant to rapid inactivation by eicosanoid oxidoreductases. In the present study, we tested the hypothesis that 17(R)‐RvD1 can provide a therapeutic benefit in IPF by reducing inflammation and pulmonary fibrosis, while leaving the normal immune response intact. Mice were exposed to bleomycin (BLM) via micro‐osmotic pump to induce pulmonary fibrosis, and were then treated with 17(R)‐RvD1 or vehicle by intraperitoneal injection. Administration of 17(R)‐RvD1 from the start of BLM treatment attenuated neutrophil alveolar infiltration, lung collagen content, and Interleukin‐1β (IL‐1β), transforming growth factor‐β1 (TGF‐β1), connective tissue growth factor (CTGF), and type I collagen mRNA expression, along with subsequent reduction in histologically detectable fibrosis. The 17(R)‐RvD1‐induced infiltration of inflammatory cells was inhibited by an antagonist of lipoxin A4 receptor/formyl peptide receptor 2 (ALX/FPR2). The administration of 17(R)‐RvD1 at the later fibrotic stage also improved the lung failure. These results suggest that 17(R)‐RvD1 attenuates pulmonary fibrosis by promoting the resolution of neutrophilic inflammation and also provides pulmonary restoration. These data highlight the therapeutic potential of 17(R)‐RvD1 in the management of this intractable disease.

Prevalence of asthma symptoms based on the European Community Respiratory Health Survey questionnaire and FENO in university students: gender differences in symptoms and FENO.

BackgroundThe fractional concentration of nitric oxide in exhaled air (FE NO) is used as a biomarker of eosinophilic airway inflammation. FE NO is increased in patients with asthma. The relationship between subjective asthma symptoms and airway inflammation is an important issue. We expected that the subjective asthma symptoms in women might be different from those in men. Therefore, we investigated the gender differences of asthma symptoms and FE NO in a survey of asthma prevalence in university students.MethodsThe information about asthma symptoms was obtained from answers to the European Community Respiratory Health Survey (ECRHS) questionnaire, and FE NO was measured by an offline method in 640 students who were informed of this study and consented to participate.ResultsThe prevalence of asthma symptoms on the basis of data obtained from 584 students (266 men and 318 women), ranging in age from 18 to 24 years, was analyzed. Wheeze, chest tightness, an attack of shortness of breath, or an attack of cough within the last year was observed in 13.2% of 584 students. When 38.0 ppb was used as the cut-off value of FE NO to make the diagnosis of asthma, the sensitivity was 86.8% and the specificity was 74.0%. FE NO was ≥ 38.0 ppb in 32.7% of students. FE NO was higher in men than in women. The prevalence of asthma symptoms estimated by considering FE NO was 7.2%; the prevalence was greater in men (9.4%) than women (5.3%). A FE NO ≥ 38.0 ppb was common in students who reported wheeze, but not in students, especially women, who reported cough attacks.ConclusionsThe prevalence of asthma symptoms in university students age 18 to 24 years in Japan was estimated to be 7.2% on the basis of FE NO levels as well as subjective symptoms. Gender differences were observed in both FE NO levels and asthma symptoms reflecting the presence of eosinophilic airway inflammation.Trial registration numberUMIN000003244

Protective Role of Proton-Sensing TDAG8 in Lipopolysaccharide-Induced Acute Lung Injury

Acute lung injury is characterized by the infiltration of neutrophils into lungs and the subsequent impairment of lung function. Here we explored the role of TDAG8 in lung injury induced by lipopolysaccharide (LPS) administrated intratracheally. In this model, cytokines and chemokines released from resident macrophages are shown to cause neutrophilic inflammation in the lungs. We found that LPS treatment increased TDAG8 expression in the lungs and confirmed its expression in resident macrophages in bronchoalveolar lavage (BAL) fluids. LPS administration remarkably increased neutrophil accumulation without appreciable change in the resident macrophages, which was associated with increased penetration of blood proteins into BAL fluids, interstitial accumulation of inflammatory cells, and damage of the alveolar architecture. The LPS-induced neutrophil accumulation and the associated lung damage were enhanced in TDAG8-deficient mice as compared with those in wild-type mice. LPS also increased several mRNA and protein expressions of inflammatory cytokines and chemokines in the lungs or BAL fluids. Among these inflammatory mediators, mRNA and protein expression of KC (also known as CXCL1), a chemokine of neutrophils, were significantly enhanced by TDAG8 deficiency. We conclude that TDAG8 is a negative regulator for lung neutrophilic inflammation and injury, in part, through the inhibition of chemokine production.

A phase I dose escalation study of biweekly gemcitabine and carboplatin in completely resected stage IB-IIIA nonsmall cell lung cancer.

Objective:We conducted a phase I dose escalation study to determine the maximum tolerated dose, recommended dose, and safety profile of a biweekly gemcitabine and carboplatin combination regimen in the treatment of patients with completely resected nonsmall cell lung cancer (NSCLC). Patients and Methods:Patients with completely resected pathologically documented stage IB, II, or IIIA NSCLC, performance status (ECOG) 0–1, with adequate bone marrow, renal, liver, and cardiac functions, were treated with gemcitabine and carboplatin. The starting dose was gemcitabine 800 mg/m2 on days 1 and 15 and carboplatin area under the time-concentration curve (AUC) 4 mg/mL/min on day 1. Gemcitabine was increased to 1000 mg/m2 (level 3). Carboplatin was increased to AUC 5 (level 2, 3). The regimen was performed every 4 weeks. The dose-limiting toxicity of the regimen was assessed during the first chemotherapy cycle. Results:Nine patients were enrolled in this study. All patients were assessed for safety. Grade 3 leukopenia occurred in 1 patient (11%) and grade 3/4 neutropenia occurred in 3 patients (33%). No other grade 3/4 toxicity was observed. No dose-limiting toxicity was experienced at dose levels 1, 2, and 3 of this schedule. Conclusion:Maximum tolerated dose was not reached in this study. Considering treatment continuation, the recommended dose for a phase II study is gemcitabine 1000 mg/m2 on days 1 and 15 and carboplatin AUC 5 on day 1, every 4 weeks. Biweekly administration of gemcitabine and carboplatin is a feasible and well-tolerated regimen for the treatment of patients with completely resected NSCLC as adjuvant chemotherapy.

CREB regulates TNF-α-induced GM-CSF secretion via p38 MAPK in human lung fibroblasts

BACKGROUND Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a cytokine that mediates eosinophilic differentiation, migration and survival, causing respiratory tract inflammation. GM-CSF is also known to be secreted from respiratory tract structural cells. However, the mechanisms of GM-CSF secretion have not been well established. METHODS Human fetal lung fibroblasts and human primary asthmatic lung fibroblasts were used for the study of tumor necrosis factor alpha (TNF-α)-induced GM-CSF secretion. GM-CSF secretion and mRNA expression were measured by enzyme-linked immunosorbent assay and quantitative real-time reverse transcription polymerase chain reaction, respectively. Knockdown of cAMP response element-binding protein (CREB) in fibroblasts was carried out by using specific small interfering RNAs of CREB. RESULTS Among respiratory tract structural cells, pulmonary fibroblasts exhibited increased GM-CSF secretion and mRNA expression after stimulation with TNF-α in a concentration-dependent manner. Moreover, a p38 mitogen-activated protein kinase (MAPK) inhibitor controlled TNF-α-induced GM-CSF secretion, and roflumilast and rolipram, inhibitors of phosphodiesterase-4, suppressed TNF-α-induced GM-CSF secretion. Consistent with this, forskolin also completely blocked GM-CSF secretion, and similar results were observed in response to cAMP treatment, suggesting that cAMP signaling suppressed TNF-α-induced GM-CSF secretion in human lung fibroblasts. Furthermore, CREB was phosphorylated through p38 MAPK but not cAMP signaling after TNF-α stimulation, and GM-CSF secretion was inhibited by CREB knockdown. Finally, these effects were also demonstrated in human primary lung fibroblasts in a patient with asthma. CONCLUSIONS CREB signaled independent of cAMP signaling and was phosphorylated by p38 MAPK following TNF-α stimulation, playing a critical role in GM-CSF secretion in human lung fibroblasts.

Acidic environment augments FcεRI-mediated production of IL-6 and IL-13 in mast cells

Although blood pH is maintained in a narrow range of around pH 7.4 in living organisms, inflammatory loci are characterized by acidic conditions. Mast cells tend to reside close to the surface of the body in areas such as the mucosa and skin where they may be exposed to exogenous acids, and they play an important role in immune responses. However, little is known about the effects of extracellular acidification on the functions of mast cell. Here, we found that extracellular acidification increased the dinitrophenyl-conjugated human serum albumin (DNP-HSA)-induced production of interleukin (IL)-6 and IL-13 in MC/9 cells or bone marrow-derived mouse mast cells sensitized with anti-DNP IgE. Extracellular acidification also inhibited migration of MC/9 cells toward DNP-HSA. In addition, acidic pH stimulated antigen-induced activation of p38 mitogen-activated protein kinase (MAPK) and protein kinase B (Akt). These findings suggest that extracellular acidification augmented antigen/IgE-induced and FcεRI-mediated production of IL-6 and IL-13 in mast cells, and that this was associated with the enhancement of p38 MAPK and Akt activation.

Elemental and immunohistochemical analysis of the lungs and hilar lymph node in a patient with asbestos exposure, a pilot study

ObjectivesStudies have shown that inhaled mine dust, such as asbestos, can be translocated to various organs including the lymph nodes. Recently, we have established a protocol that enables us to identify inhaled elements using paraffin embedded lung specimens by in-air microparticle-induced X-ray emission (micro-PIXE). However, little research has examined the concentration of these inhaled fibers in various organs or the mechanisms of their translocation. In this study, we compared the concentration of inhaled fibers in the lung parenchyma to the concentration in the hilar lymph node as well as to determine the elemental spatial distribution of the inhaled fibers in a patient with occupational asbestos exposure.MethodsLung tissues and hilar lymph node in a patient with asbestos exposure were used in this study. Elemental analysis was performed by in-air micro-PIXE. Immunohistochemical analysis was performed using anti CD163, smooth muscle actin, vimentin and β-catenin antibody.ResultsThe analysis revealed that the amount of inhaled silicon was approximately 6 times higher in the lymph node than in the lungs. The spatial analysis showed that silicon, iron and aluminium were co-localized in the hilar lymph node. The immunohistochemical analysis showed localized agreement of the inhaled fibers with macrophages, smooth muscle actin, and vimentin in the hilar lymph node.ConclusionsThis study showed that in-air micro-PIXE could be useful for analyzing the elemental distribution and quantification of inhaled fibers in the human body. Furthermore, immunohistochemistry in combination with in-air micro-PIXE analyses may help to determine the mechanism of mine dust distribution in vivo.

The Onset of Eosinophilic Pneumonia Preceding Anti-synthetase Syndrome

A 66-year-old man had been treated with prednisolone for eosinophilic pneumonia for 8 years. His slowly progressing cough and dyspnea were accompanied by elevated levels of fibrotic serological markers and an increased reticular shadow on chest computed tomography images. The patient had recently tested positive for anti-EJ antibodies, a type of anti-aminoacyl-tRNA synthetase antibody; therefore, we diagnosed him with an exacerbation of interstitial pneumonia due to anti-synthetase syndrome (ASS). He was treated with tacrolimus and an increased prednisolone dosage. We herein present the first reported case of eosinophilic pneumonia preceding anti-EJ antibody-positive ASS.