Satoshi Kamata

Novel Monoclonal Antibody LpMab-17 Developed by CasMab Technology Distinguishes Human Podoplanin from Monkey Podoplanin

Podoplanin (PDPN) is a type-I transmembrane sialoglycoprotein, which possesses a platelet aggregation-stimulating (PLAG) domain in its N-terminus. Among the three PLAG domains, O-glycan on Thr52 of PLAG3 is critical for the binding with C-type lectin-like receptor-2 (CLEC-2) and is essential for platelet-aggregating activity of PDPN. Although many anti-PDPN monoclonal antibodies (mAbs) have been established, almost all mAbs bind to PLAG domains. We recently established CasMab technology to produce mAbs against membranous proteins. Using CasMab technology, we produced a novel anti-PDPN mAb, LpMab-17, which binds to non-PLAG domains. LpMab-17 clearly detected endogenous PDPN of cancer cells and normal cells in Western-blot, flow cytometry, and immunohistochemistry. LpMab-17 recognized glycan-deficient PDPN in flow cytometry, indicating that the interaction between LpMab-17 and PDPN is independent of its glycosylation. The minimum epitope of LpMab-17 was identified as Gly77-Asp82 of PDPN using enzyme-linked immunosorbent assay. Of interest, LpMab-17 did not bind to monkey PDPN, whereas the homology is 94% between human PDPN and monkey PDPN, indicating that the epitope of LpMab-17 is unique compared with the other anti-PDPN mAbs. The combination of different epitope-possessing mAbs could be advantageous for the PDPN-targeting diagnosis or therapy.

Histone deacetylase inhibitor restores surfactant protein-C expression in alveolar-epithelial type II cells and attenuates bleomycin-induced pulmonary fibrosis in vivo.

ABSTRACT Aim: Surfactant protein-C (SP-C) of alveolar epithelial type II cells (ATII) plays a key role in maintaining alveolar integrity and repair. Mutations or decreased expression of SFTPC, the gene encoding SP-C, causes ATII injury and aberrant repair of the lung tissue to develop pulmonary fibrosis. Histone deacetylases (HDACs) epigenetically remove acetyl groups from acetylated histones and regulate transcription. HDAC inhibitors attenuated epithelial-to-mesenchymal transition (EMT) and fibrotic disorders. The aim of this study is to investigate whether Trichostatin A (TSA), a pan-HDAC inhibitor, epigenetically exerts a protective effect on ATII against fibrotic changes via the restoration of SFTPC expression. Materials and Methods: We treated A549 cells with TGF-β1 to induce EMT, followed by TSA treatment. We evaluated SFTPC mRNA, histone acetylation levels in the SFTPC gene promoter region, and pro-SP-C protein. C57BL6/J mice were treated with intratracheal bleomycin instillation followed by TSA administration. Histological changes and Sftpc mRNA expression in isolated ATII were evaluated. Results: TGF-β1 treatment decreased SFTPC mRNA in A549 cells. TSA restored SFTPC mRNA, and increased histone H4 acetylation in the SFTPC promoter region in vitro. The administration of TSA partially attenuated BLM-induced pulmonary fibrosis and increased the Sftpc mRNA expression in isolated ATII from bleomycin-treated lungs in vivo. Conclusions: Decreased expression of SFTPC by TGF-β1 treatment was restored by TSA via hyperacetylation of histone H4 in the promoter region. TSA partially attenuated pulmonary fibrosis and increased Sftpc mRNA in ATII. Our findings suggest that the epigenetic restoration of SP-C would be a therapeutic target for pulmonary fibrosis.

Lung Squamous Cell Carcinoma Arising in a Patient with Adult-onset Recurrent Respiratory Papillomatosis

A 75-year-old male was admitted to our hospital in December 2011 with a mass in the right upper pulmonary lobe. He was incidentally diagnosed as having tracheal papillomas 10 years ago. Bronchoscopy revealed multiple polypoid papillomas in the dorsal lesion of the trachea. Polymerase chain reaction amplification detected human papillomavirus type 11 DNA in the papilloma tissues. A computed tomography scan demonstrated the occlusion of the right superior segment bronchus with distal consolidation. Furthermore, F-18 fluoro-2-deoxy-D-glucose positron emission tomography and computed tomography showed intense tracer uptake in the right superior segment of the lung. He underwent a right upper lobectomy. The tumor was seen as a rounded nodule, ≈ 2 cm in diameter. Histological examination of the tumor revealed squamous papilloma with papillary and solid architecture surrounded by accumulation of acute inflammatory cells. Furthermore, in a part of the tumor, squamous cell carcinoma was also present. The lymph nodes were free of tumor. After the surgery, he continued to undergo endoscopic microwave resection. Recurrent respiratory papillomatosis is a rare disease that can cause life-threatening airway compromise and malignant transformation. The present case indicates that F-18 fluoro-2-deoxy-D-glucose positron emission tomography and computed tomography is indispensable for early detection of lung cancer arising in a patient with recurrent respiratory papillomatosis.

Pulmonary Embolism Due to Popliteal Venous Aneurysm

A 33-year-old man was admitted to our hospital for shortness of breath on exertion. His symptoms started suddenly a week before admission when he was driving a car and worsened daily. He was amateur football player and had no history of hypertension, dyslipidemia, diabetes mellitus, smoking, or leg injury. On admission, an arterial pulse oxygen saturation monitor showed that his arterial blood oxygen saturation was 94% with room air. His blood pressure was 114/82 mm Hg and his pulse rate was 92/min with regular rhythm. His height was 162 cm and body weight was 62 kg. No other outstanding physical abnormalities were observed. Laboratory data showed slightly an elevated C-reactive protein level of 0.87 mg/dL with a normal white blood cell count of 6100 cells/mL. Arterial blood sampling revealed a normal CO2 level of 41 mm Hg and pH of 7.42 with low oxygen tension (52 mm Hg). An ECG showed a small S wave in lead I and a small Q wave and inverted T wave in …

Reoperative minimally invasive axillocoronary artery bypass to the obtuse marginal branch

A 73-year-old man was admitted with unstable angina, having severe coronary artery disease involving 3 vessels. He had undergone coronary artery bypass grafting to the left anterior descending artery and the obtuse marginal branch using saphenous vein grafts in 1979. Computed tomography showed severe calcium deposition and atherosclerosis in the ascending and descending aorta. We conducted axillocoronary artery bypass to the obtuse marginal branch and left internal thoracic artery as an in situ graft to the left anterior descending artery without cardiopulmonary bypass. Grafts were satisfactory and clinical results good.

Expression of cytochrome P450 mRNAs in Type II alveolar cells from subjects with chronic obstructive pulmonary disease

Inhaled drugs are critical for the treatment of inflammatory airway diseases such as chronic obstructive pulmonary disease (COPD). To develop better therapeutics for pulmonary disease it is of potential importance to understand molecular mechanisms of local biotransformation in the lung. Alveolar epithelial type II (ATII) cells have a key role in homeostasis in the lung, but little is known about expression patterns of genes encoding cytochrome P450 (CYP) enzymes in ATII cells. In addition, alteration of CYP gene expression has not been fully defined in COPD. We previously established a method to purify ATII cells from the adult human lung using fluorescence‐activated cell sorting. By employing this technique we determined gene expression patterns of 14 CYP enzymes in ATII cells from nonsmokers (n = 4) and smokers (n = 4), both having normal pulmonary function. Although most CYP genes are highly expressed in primary hepatocytes, we found that CYP1B1 mRNA expression was 7.2‐fold higher in ATII compared to hepatocytes (P = .0275). Additionally we noted a 3.0‐fold upregulation of CYP2C19 and 50% reduction in CYP2J2 mRNA expressions in ATII cells isolated from patients with COPD (n = 3) compared to smokers without COPD (n = 4). These data, for the first time, detail a comprehensive set of genes encoding CYP enzymes in human ATII cells and highlights differentially expressed CYP mRNAs of patients with COPD. Such understanding may have important implications for the development of novel inhaled drugs.

The Role of Lysophosphatidic Acid on Airway Epithelial Cell Denudation in a Murine Heterotopic Tracheal Transplant Model.

Background Chronic rejection is the major leading cause of morbidity and mortality after lung transplantation. Obliterative bronchiolitis (OB), a fibroproliferative disorder of the small airways, is the main manifestation of chronic lung allograft rejection. However, there is currently no treatment for the disease. We hypothesized that lysophosphatidic acid (LPA) participates in the progression of OB. The aim of this study was to reveal the involvement of LPA on the lesion of OB. Methods Ki16198, an antagonist specifically for LPA1 and LPA3, was daily administered into the heterotopic tracheal transplant model mice at the day of transplantation. At days 10 and 28, the allografts were isolated and evaluated histologically. The messenger RNA levels of LPAR in microdissected mouse airway regions were assessed to reveal localization of lysophosphatidic acid receptors. The human airway epithelial cell was used to evaluate the mechanism of LPA-induced suppression of cell adhesion to the extracellular matrix (ECM). Results The administration of Ki16198 attenuated airway epithelial cell loss in the allograft at day 10. Messenger RNAs of LPA1 and LPA3 were detected in the airway epithelial cells of the mice. Lysophosphatidic acid inhibited the attachment of human airway epithelial cells to the ECM and induced cell detachment from the ECM, which was mediated by LPA1 and Rho-kinase pathway. However, Ki16198 did not prevent obliteration of allograft at day 28. Conclusions The LPA signaling is involved in the status of epithelial cells by distinct contribution in 2 different phases of the OB lesion. This finding suggests a role of LPA in the pathogenesis of OB.

Mid-Term Results of the Use of Radial Artery Graft for Coronary Artery Bypass (Radial Artery Graft Versus Saphenous Vein Graft).

術後1年以上経過した左回旋枝もしくは対角枝に橈骨動脈を用いたCABG134例を対象に術後中期遠隔成績を大伏在静脈と比較し検討した.平均観察期間は2年4ヵ月.RAは108本,SVGは42本をこの領域にバイパスした.吻合部位はRA群がPLに69本,OMに29本,DBに10本のバイパスを施行した.SVG群はそれぞれ26本,14本,2本であった.早期グラフト開存率はRA群では97.9%,SVG群では91.7%であった.術後1年ごとのTMTによる評価ではRA群では99.0%が,SVGでは90.9%が陰性であった.冠動脈造影での開存率はRA群では92.9%で,SVG群では50.0%であった.左回旋枝,対角枝に対するCABGのグラフトとしてRAは有用と考えられた.