Papers - SAITO Atsushi

Exploring the Potential of a P2X3 Receptor Antagonist: Gefapixant in the Management of Persistent Cough Associated with Interstitial Lung Disease

Tomoyuki Takahashi, Atsushi Saito, Takafumi Yorozuya, Hirotaka Nishikiori, Koji Kuronuma, Hirofumi Chiba

Medicina    2025.05

DOI

Rapid and Integrated Bacterial Evolution Analysis unveils gene mutations and clinical risk of Klebsiella pneumoniae

Kojiro Uemura, Toyotaka Sato, Soh Yamamoto, Noriko Ogasawara, Jirachaya Toyting, Kotaro Aoki, Akira Takasawa, Masayuki Koyama, Atsushi Saito, Takayuki Wada, Kaho Okada, Yurie Yoshida, Koji Kuronuma, Chie Nakajima, Yasuhiko Suzuki, Motohiro Horiuchi, Kenichi Takano, Satoshi Takahashi, Hirofumi Chiba, Shin-ichi Yokota

Nature Communications    2025.03

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Management of anti-melanoma differentiation-associated gene 5 antibody-induced refractory dermatomyositis complicated by interstitial pneumonia using tofacitinib and its outcomes: a case report.

Yui Imai, Takafumi Yorozuya, Taku Hatakeyama, Takumi Nishimaki, Tomoyuki Takahashi, Tatsuru Ishikawa, Shun Kondoh, Yuichiro Asai, Yuki Mori, Atsushi Saito, Hirotaka Nishikiori, Michiko Hosaka, Hirofumi Chiba

Journal of medical case reports   18 ( 1 ) 471 - 471  2024.09  [International journal]

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BACKGROUND: Clinical amyopathic dermatomyositis is characterized by cutaneous symptoms but lacks muscle symptoms. Anti-melanoma differentiation-associated gene 5 antibodies are frequently found in Japanese patients with clinical amyopathic dermatomyositis. Patients with rapidly progressive interstitial lung disease with positive anti-melanoma differentiation-associated gene 5 antibodies have poor prognoses, and majority of them are treated with combination immunosuppressive therapy; however, the best treatment is yet to be determined. CASE PRESENTATION: A 52-year-old Asian male patient presented with a chief complaint of dyspnea on exertion. He had a typical skin rash and rapidly progressive interstitial pneumonia. Additionally, anti-melanoma differentiation-associated gene 5 antibodies were detected; therefore, he was diagnosed with dermatomyositis-associated interstitial pneumonia. Respiratory failure worsened despite administering steroid pulse therapy, tacrolimus, and cyclophosphamide. Consequently, plasma exchange was performed on day 13 of admission. After a slight improvement, the patient's respiratory failure worsened. Thus, cyclophosphamide was replaced by tofacitinib on day 28. Although respiratory failure improved and the progression of interstitial pneumonia seemed under control, βD-glucan level increased and Aspergillus antigen was detected on day 49. Micafungin and voriconazole were administered, but the patient succumbed to worsening respiratory failure on day 61. The pathological autopsy revealed multiple nodular lesions with cavity formation in both lungs and the presence of Aspergillus with severe neutrophilic infiltration and necrosis, which supported the diagnosis of invasive pulmonary aspergillosis. CONCLUSION: The patient with anti-melanoma differentiation-associated gene 5 antibody-related rapidly progressive interstitial lung disease, whose disease was difficult to control after the administration of triple immunosuppressive therapy (steroids, tacrolimus, and cyclophosphamide), showed good response with tofacitinib. Unfortunately, the patient died of invasive pulmonary aspergillosis owing to severe immunosuppression; thus, the signs of complications should be promptly detected.

DOI PubMed

Therapeutic effect of long-acting muscarinic antagonist for treating uncontrolled asthma assessed using impulse oscillometry.

Hiroyuki Sugawara, Atsushi Saito, Saori Yokoyama, Hirofumi Chiba

Respiratory research   25 ( 1 ) 300 - 300  2024.08  [International journal]

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BACKGROUND: In recent years, the incorporation of LAMAs into asthma therapy has been expected to enhance symptom control. However, a significant number of patients with asthma continue to experience poorly managed symptoms. There have been limited investigations on LAMA-induced airway alterations in asthma treatment employing IOS. In this study, we administered a LAMA to patients with poorly controlled asthma, evaluated clinical responses and respiratory function, and investigated airway changes facilitated by LAMA treatments using the IOS. METHODS: Of a total of 1282 consecutive patients with asthma, 118 exhibited uncontrolled symptoms. Among them, 42 switched their treatment to high-dose fluticasone furoate/umeclidinium/vilanterol (FF/UMEC/VI) (ICS/LABA/LAMA). The patients were then assessed using AHQ-33 or LCQ and ACT. Spirometry parameters (such as FEV1 or MMEF) and IOS parameters (such as R20 or AX) were measured and compared before and after exacerbations and the addition of LAMA. RESULTS: Of the 42 patients, 17 who switched to FF/UMEC/VI caused by dyspnea exhibited decreased pulmonary function between period 1 and baseline, followed by an increase in pulmonary function between baseline and period 2. Significant differences were observed in IOS parameters such as R20, R5-R20, Fres, or AX between period 1 and baseline as well as between baseline and period 2. Among the patients who switched to inhaler due to cough, 25 were classified as responders (n = 17) and nonresponders (n = 8) based on treatment outcomes. Among nonresponders, there were no significant differences in spirometry parameters such as FEV1 or PEF and IOS parameters such as R20 or AX between period 1 and baseline. However, among responders, significant differences were observed in all IOS parameters, though not in most spirometry parameters, between period 1 and baseline. Furthermore, significant differences were noted between baseline and period 2 in terms of FEV1, %MMEF, %PEF, and all IOS parameters. CONCLUSION: ICS/LABA/LAMA demonstrates superiority over ICS/LABA in improving symptoms and lung function, which is primarily attributed to the addition of LAMA. Additionally, IOS revealed the effectiveness of LAMA across all airway segments, particularly in the periphery. Hence, LAMA can be effective against various asthma phenotypes characterized by airway inflammation, even in real-world cases.

DOI PubMed

N-glycan on N262 of FGFR3 regulates the intracellular localization and phosphorylation of the receptor.

Hashimoto, U, Fujitani, N, Uehara, Y, Okamoto, H, Saito, A, Ito, F, Ariki, S, Shiratsuchi, A, Hasegawa, Y, Takahashi, M

Biochim. Biophys. Acta Gen. Subj.   1868 ( 4 ) 130565 - 130565  2024.04  [Refereed]

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The impact of respiratory reactance in oscillometry on survival in patients with idiopathic pulmonary fibrosis.

Tatsuru Ishikawa, Hirotaka Nishikiori, Yuki Mori, Keiko Fujino, Atsushi Saito, Mamoru Takahashi, Koji Kuronuma, Shiro Hinotsu, Hirofumi Chiba

BMC pulmonary medicine   24 ( 1 ) 10 - 10  2024.01  [International journal]

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BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is a progressive disease with a poor prognosis. Pulmonary function tests (PFTs) aid in evaluating the disease status of IPF. The clinical significance of oscillometry measurements in interstitial lung diseases has recently been reported. Our previous study showed that respiratory reactance (Xrs) measured by oscillometry reflected disease severity and predicted subsequent lung capacity decline in patients with IPF. However, the direct impact of Xrs on survival needs to be determined, and there are currently no reference values in oscillometry to predict prognosis. Therefore, this study aimed to investigate the association between oscillometry measurements, particularly Xrs, and survival in patients with IPF and to determine the cutoff values of Xrs that predict 3-year survival. METHODS: We analyzed the relationship between the measured values of PFT and oscillometry derived from 178 patients with IPF. Univariate and multivariate Cox proportional hazards analyses were performed to investigate the relationships between clinical indices at the time of the first oscillometry and survival. We performed the time-dependent receiver operating characteristic (ROC) curve analysis to set the optimized cutoff values of Xrs for 3-year survival prediction. We examined the discriminating power of cutoff values of Xrs on survival using the Kaplan-Meier method and the log-rank test. RESULTS: Xrs components, especially in the inspiratory phase (In), significantly correlated with the PFT values. In the multivariate analyses, Xrs (all of reactance at 5 Hz [X5], resonant frequency [Fres], and low-frequency reactance area [ALX] in the inspiratory phase) had a significant impact on survival (X5, p = 0.003; Fres, p = 0.016; ALX, p = 0.003) independent of age, sex, and other prognostic factors derived from the univariate analysis. The area under the ROC curve was 0.765, 0.759, and 0.766 for X5 In, Fres In, and ALX In, with cutoff values determined at - 0.98, 10.67, and 5.32, respectively. We found significant differences in survival after dividing patients using each of the cutoff values of Xrs. CONCLUSIONS: In patients with IPF, Xrs measured by oscillometry significantly impacted survival. We also determined the cutoff values of Xrs to discriminate patients with poor prognoses.

DOI PubMed

Pseudo-outbreak of Mycobacterium lentiflavum at a general hospital in Japan.

Yutaro Nagano, Koji Kuronuma, Yasuo Kitamura, Kanami Nagano, Hayato Yabe, Sayaka Kudo, Toyotaka Sato, Shinya Nirasawa, Mami Nakae, Motohiro Horiuchi, Shin-Ichi Yokota, Yoshihiro Fujiya, Atsushi Saito, Satoshi Takahashi, Hirofumi Chiba

Infection control and hospital epidemiology   44 ( 11 ) 1 - 7  2023.04  [International journal]

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BACKGROUND: Mycobacterium lentiflavum is a slow-growing nontuberculous mycobacterium that is widely distributed in soil and water systems, but it is sometimes pathogenic to humans. Although cases of M. lentiflavum infections are rare, 22 isolates of M. lentiflavum were identified at a single hospital in Japan. We suspected a nosocomial outbreak; thus, we conducted transmission pattern and genotype analyses. METHODS: Cases of M. lentiflavum isolated at Kushiro City General Hospital in Japan between May 2020 and April 2021 were analyzed. The patient samples and environmental culture specimens underwent whole-genome sequencing (WGS). Additionally, we retrospectively collected clinical data from patient medical records. RESULTS: Altogether, 22 isolates of M. lentiflavum were identified from sputum and bronchoalveolar lavage samples. Clinically, the instances with M. lentiflavum isolates were considered contaminants. In the WGS analysis, 19 specimens, including 18 patient samples and 1 environmental culture from the hospital's faucet, showed genetic similarity. The frequency of M. lentiflavum isolation decreased after we prohibited the use of taps where M. lentiflavum was isolated. CONCLUSIONS: WGS analysis identified that the cause of M. lentiflavum pseudo-outbreak was the water used for patient examinations, including bronchoscopy.

DOI PubMed

ニボルマブおよびイピリムマブ療法における総腫瘍量と重症免疫関連有害事象の関連性

太田 雄介, 角 俊行, 道又 春彦, 永山 大貴, 越野 友太, 渡辺 裕樹, 山田 裕一, 齋藤 充史, 千葉 弘文

日本呼吸器学会誌 ( (一社)日本呼吸器学会 )  12 ( 増刊 ) 382 - 382  2023.03

ニボルマブおよびイピリムマブ療法における総腫瘍量と重症免疫関連有害事象の関連性

太田 雄介, 角 俊行, 道又 春彦, 永山 大貴, 越野 友太, 渡辺 裕樹, 山田 裕一, 齋藤 充史, 千葉 弘文

日本呼吸器学会誌 ( (一社)日本呼吸器学会 )  12 ( 増刊 ) 382 - 382  2023.03

The Soluble Lectin Families as Novel Biomarkers for COVID-19 Pneumonia.

Haruka Takenaka, Atsushi Saito, Koji Kuronuma, Keigo Moniwa, Hirotaka Nishikiori, Satoshi Takahashi, Hirofumi Chiba

In vivo (Athens, Greece)   37 ( 4 ) 1721 - 1728  2023  [International journal]

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BACKGROUND/AIM: The lung-specific soluble lectins, SP-A and SP-D have been clinically used to diagnose interstitial lung disease, but their clinical significance in COVID-19 remains controversial. This study was undertaken to determine their association with other lectins (MBL and FCN1), disease severity, and radiographs in COVID-19 patients. PATIENTS AND METHODS: A total of 131 patients with COVID-19 admitted in the Sapporo Medical University Hospital between May 22 and September 19, 2021, were enrolled in the study. Data including demographics, medical history, symptoms, signs, laboratory findings, and radiological images were collected from the patients' medical records. Chest computed tomography (CT) scanning was performed at admission. Serum levels of surfactant protein A and D (SP-A and SP-D), mannose-binding lectin (MBL) and ficolin1 (FCN1) were measured using enzyme-linked immunosorbent assay (ELISA) kits. RESULTS: Compared to the control group, the COVID-19 group had significantly higher serum SP-A and FCN1 levels on admission (SP-A: 59.60±38.89 vs. 35.61±11.22 ng/ml; p<0.01, FCN1: 542.45±506.04 vs. 250.6±161.1 ng/ml; p<0.01). The severe group in COVID-19 had significantly higher serum SP-D and lower MBL levels than the non-severe group (SP-D: 141.7±155.7 vs. 61.41±54.54 ng/ml; p<0.01, MBL: 1,670±1,240 vs. 2,170±1,140 ng/ml; p<0.05). SP-D strongly reflected the degree of imaging findings, whereas SP-A showed a significant correlation, albeit slightly weaker than SP-D. Conversely, MBL and FNC1 were not significantly correlated with imaging findings. CONCLUSION: Among soluble serum lectins, SP-A and SP-D may be more sensitive to CT findings than reported disease biomarkers such as IL-6, LDH, and CRP due to their lung-specific characteristics.

DOI PubMed

Serum Testosterone Is Associated With the Severity of COVID-19.

Ema Suzuki, Koji Kuronuma, Ryosei Murai, Yoshihiro Fujiya, Atsushi Saito, Hirofumi Chiba, Satoshi Takahashi

In vivo (Athens, Greece)   37 ( 5 ) 2314 - 2319  2023  [International journal]

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BACKGROUND/AIM: Coronavirus disease 2019 (COVID-19) is more likely to be severe in men than in women. Its association with sex hormones as an aggravating factor for male patients has been attracting attention. This study aimed to investigate whether serum testosterone is associated with the aggravation of COVID-19. PATIENTS AND METHODS: Serum testosterone concentrations in 116 male patients with COVID-19 and residual serum were measured and examined upon their admission to Sapporo Medical University Hospital between February 1, 2020 and March 31, 2021. RESULTS: Blood samples collected from these patients with COVID-19 were analyzed. The serum testosterone levels were 2.19±1.35, 1.29±0.88, and 0.75±0.58 ng/ml in mild, moderate, and severe groups, respectively. Patients with severe COVID-19 on admission had lower testosterone levels (p<0.001). At a cutoff level of 1.31 ng/ml, the area under the curve for the comparison of severe with non-severe cases was 0.825. Furthermore, serum testosterone levels negatively correlated with C-reactive protein and serum amyloid A levels but positively correlated with calcium, zinc, C3, and C4. CONCLUSION: In male patients with COVID-19, low serum testosterone levels correlated with disease severity, accompanied by a strong inflammatory reaction and proportion of complement consumption.

DOI PubMed

Protective effect of Bifidobacterium longum BB536 against nausea caused by pirfenidone in a mouse model of pellagra.

Koji Kuronuma, Natsumi Susai, Tomohiro Kuroita, Takeshi Yoshioka, Atsushi Saito, Hirofumi Chiba

Bioscience of microbiota, food and health   42 ( 3 ) 195 - 202  2023  [Domestic journal]

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Pellagra is caused by abnormal intake and/or use of nicotinic acid and is known in part to be induced by the use of medications such as isoniazid or pirfenidone. We previously investigated atypical phenotypes of pellagra, such as nausea, using a mouse model of pellagra and found that gut microbiota play an important role in the development of these phenotypes. Here, we investigated the effect of Bifidobacterium longum BB536 on pellagra-related nausea caused by pirfenidone in our mouse model. Our pharmacological data indicated that pirfenidone (PFD) causes modulation of the gut microbiota profile, which appeared to play an important role in the development of pellagra-related nausea. A gut microbiota-mediated protective effect of B. longum BB536 against nausea caused by PFD was also identified. Finally, the urinary ratio of nicotinamide/N-methylnicotinamide was shown to be a biomarker of pellagra-like adverse effects induced by PFD, and it may contribute to the prevention of these effects in patients with idiopathic pulmonary fibrosis.

DOI PubMed

Pneumocystis jirovecii Pneumonia Associated with COVID-19 in Patients with Interstitial Pneumonia.

Tomoyuki Takahashi, Atsushi Saito, Koji Kuronuma, Hirotaka Nishikiori, Hirofumi Chiba

Medicina (Kaunas, Lithuania)   58 ( 9 )  2022.08  [International journal]

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Here, we report two cases of patients with interstitial pneumonia (IP) on steroids who developed Pneumocystis jirovecii pneumonia (PJP) following coronavirus disease 2019 (COVID-19) infection. Case 1: A 69-year-old man on 10 mg of prednisolone (PSL) daily for IP developed new pneumonia shortly after his COVID-19 infection improved and was diagnosed with PJP based on chest computed tomography (CT) findings and elevated serum β-D-glucan levels. Trimethoprim-sulfamethoxazole (TMP-SMZ) was administered, and the pneumonia resolved. Case 2: A 70-year-old woman taking 4 mg/day of PSL for IP and rheumatoid arthritis developed COVID-19 pneumonia, which resolved mildly, but her pneumonia flared up and was diagnosed as PJP based on CT findings, elevated β-D-glucan levels, and positive polymerase chain reaction for P. jirovecii DNA in the sputum. The autopsy revealed diffuse alveolar damage, increased collagen fiver and fibrotic foci, mucinous component accumulation, and the presence of a P. jirovecii cyst. In conclusion, steroids and immunosuppressive medications are well-known risk factors for PJP. Patients with IP who have been taking these drugs for a long time are frequently treated with additional steroids for COVID-19; thus, PJP complications should be avoided in such cases.

DOI PubMed

Association between annual change in FEV1 and comorbidities or impulse oscillometry in chronic obstructive pulmonary disease.

Hiroyuki Sugawara, Atsushi Saito, Saori Yokoyama, Kazunori Tsunematsu, Hirofumi Chiba

BMC pulmonary medicine   22 ( 1 ) 185 - 185  2022.05  [International journal]

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BACKGROUND: Chronic obstructive pulmonary disease (COPD) is characterized by persistent respiratory symptoms and airflow limitation. The decline in forced expiratory volume in one second (FEV1) is considered to be one of the most important outcome measures for evaluating disease progression. However, the only intervention proven to improve COPD prognosis is smoking cessation. This study therefore investigated the factors associated with annual FEV1 decline in COPD. METHODS: This retrospective study followed up 65 patients treated for COPD for 5 years: 13 current smokers and 52 former smokers, 25 with pneumonia, 24 with asthma, 18 with cancer, and 17 with cardiovascular disease. The patients were divided into groups based on clinical cutoff parameters of the impulse oscillometry system (IOS): 11 high and 54 low R5, 8 high and 57 low R20, 21 high and 44 low R5-R20, 26 high and 39 low X5, 38 high and 27 low Fres, and 36 high and 29 low AX. We investigated whether the decline in FEV1 was associated with comorbidities and IOS parameters. RESULTS: The annual change in FEV1 over 5 years was significantly affected by smoking status (current - 66.2 mL/year vs. former - 5.7 mL/year, p < 0.01), pneumonia (with - 31.5 mL/year vs. without - 8.9 mL/year, p < 0.05), asthma (with - 30.2 mL/year vs. - 10.8 mL/year, p < 0.01), but not by cancer and cardiovascular disease. In the groups defined by IOS results, only the high AX group had significantly more annual decline in FEV1 and %FEV1 than the low AX group (- 22.1 vs. - 12.8, p < 0.05 and - 0.20 vs. 0.40, p < 0.05, respectively). CONCLUSIONS: Continuing smoking as well as complications in pneumonia and asthma would be risk factors for the progression of COPD. AX might be a suitable parameter to predict the prognosis of patients with COPD.

DOI PubMed

COVID-19肺炎重症度予測マーカーとしてのIL-6、INF-λ3、NGALの検討

黒沼 幸治, 中江 舞美, 藤谷 好弘, 高橋 聡, 齋藤 充史, 安田 健人, 千葉 弘文

日本化学療法学会雑誌 ( (公社)日本化学療法学会 )  70 ( Suppl.A ) 299 - 299  2022.05

COVID-19 臨床経過予測因子 COVID-19肺炎重症度予測マーカーとしてのIL-6、INF-λ3、NGALの検討

齋藤 充史, 安田 健人, 黒沼 幸治, 中江 舞美, 藤谷 好弘, 高橋 聡, 千葉 弘文

日本呼吸器学会誌 ( (一社)日本呼吸器学会 )  11 ( 増刊 ) 153 - 153  2022.04

N-glycosylation regulates MET processing and signaling.

Atsushi Saitou, Yoshihiro Hasegawa, Naoki Fujitani, Shigeru Ariki, Yasuaki Uehara, Ukichiro Hashimoto, Atsushi Saito, Koji Kuronuma, Kunio Matsumoto, Hirofumi Chiba, Motoko Takahashi

Cancer science   113 ( 4 ) 1292 - 1304  2022.04  [International journal]

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MET, the receptor for the hepatocyte growth factor (HGF), is strongly associated with resistance to tyrosine kinase inhibitors, key drugs that are used in the therapy of non-small cell lung cancer. MET contains 11 potential N-glycosylation sites, but the site-specific roles of these N-glycans have not been elucidated. We report herein that these N-glycans regulate the proteolytic processing of MET and HGF-induced MET signaling, and that this regulation is site specific. Inhibitors of N-glycosylation were found to suppress the processing and trafficking of endogenous MET in H1975 and EBC-1 lung cancer cells and exogenous MET in CHO-K1 cells. We purified the recombinant extracellular domain of human MET and determined the site-specific N-glycan structures and occupancy using mass spectrometry. The results indicated that most sites were fully glycosylated and that the dominant population was the complex type. To examine the effects of the deletion of N-glycans of MET, we prepared endogenous MET knockout Flp-In CHO cells and transfected them with a series of N-glycan-deletion mutants of MET. The results showed that several N-glycans are implicated in the processing of MET. The findings also suggested that the N-glycans of the SEMA domain of MET positively regulate HGF signaling, and the N-glycans of the region other than the SEMA domain negatively regulate HGF signaling. Processing, cell surface expression, and signaling were significantly suppressed in the case of the all-N-glycan-deletion mutant. The overall findings suggest that N-glycans of MET affect the status and the function of the receptor in a site-specific manner.

DOI PubMed

Treatment of air leakage using the VIO soft coagulation system: a mouse pulmonary air leak model.

Yuki Takahashi, Atsushi Saito, Yuji Sakuma, Makoto Tada, Ryunosuke Maki, Motoko Takahashi, Atsushi Watanabe

Surgery today   51 ( 9 ) 1521 - 1529  2021.09  [Domestic journal]

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PURPOSE: We aimed to compare the efficacy of the VIO soft coagulation system (VSCS) for the treatment of air leaks by sealing with fibrin glue, and also assess the histological alterations that occur after soft coagulation. METHODS: A mouse pulmonary air leak model was designed. The pulmonary fistula was subsequently coagulated with the VSCS or sealed with fibrin glue with polyglycolic acid (PGA) sheets. The burst pressure at air leak recurrence was measured in each group, and the results were compared. We also evaluated the histological alterations in the mouse pulmonary air leak model after soft coagulation with the VSCS. RESULTS: The burst pressure in the soft coagulation group (80 W/Effect 5) (median 42.8; range 35.4-53.8 cmH2O) was similar to that in the fibrin glue group (median 41.5; range 34.6-43.9 cmH2O) (p = 0.21). Histological examinations revealed that the visceral pleura remained torn, the structure of the pulmonary alveolus was maintained, and the coagulated fistula was covered with a fibrin membrane in the soft coagulation group. CONCLUSIONS: The pressure resistance following soft coagulation was equivalent to that after sealing using fibrin glue with PGA sheets. The air leaks were likely controlled by covering the fistula with a fibrin membrane after soft coagulation with the VSCS.

DOI PubMed

Integrated Structural Analysis of N-Glycans and Free Oligosaccharides Allows for a Quantitative Evaluation of ER Stress.

Naoki Fujitani, Shigeru Ariki, Yoshihiro Hasegawa, Yasuaki Uehara, Atsushi Saito, Motoko Takahashi

Biochemistry   60 ( 21 ) 1708 - 1721  2021.06  [International journal]

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Endoplasmic reticulum (ER) stress has been reported in a variety of diseases. Although ER stress can be detected using specific markers, it is still difficult to quantitatively evaluate the degree of stress and to identify the cause of the stress. The ER is the primary site for folding of secretory or transmembrane proteins as well as the site where glycosylation is initiated. This study therefore postulates that tracing the biosynthetic pathway of asparagine-linked glycans (N-glycans) would be a reporter for reflecting the state of the ER and serve as a quantitative descriptor of ER stress. Glycoblotting-assisted mass spectrometric analysis of the HeLa cell line enabled quantitative determination of the changes in the structures of N-glycans and degraded free oligosaccharides (fOSs) in response to tunicamycin- or thapsigargin-induced ER stress. The integrated analysis of neutral and sialylated N-glycans and fOSs showed the potential to elucidate the cause of ER stress, which cannot be readily done by protein markers alone. Changes in the total amount of glycans, increase in the ratio of high-mannose type N-glycans, increase in fOSs, and changes in the ratio of sialylated N-glycans in response to ER stress were shown to be potential descriptors of ER stress. Additionally, drastic clearance of accumulated N-glycans was observed in thapsigargin-treated cells, which may suggest the observation of ER stress-mediated autophagy or ER-phagy in terms of glycomics. Quantitative analysis of N-glycoforms composed of N-glycans and fOSs provides the dynamic indicators reflecting the ER status and the promising strategies for quantitative evaluation of ER stress.

DOI PubMed

新型コロナウイルス感染症が北海道内の病院・診療所の診療に与えた影響に関するアンケート調査

齋藤 充史, 千葉 弘文, 服部 健史, 黒沼 幸治, 中久保 祥, 鎌田 啓佑, 田代 典夫, 田中 裕士, 福家 聡, 今野 哲

日本呼吸器学会誌 ( (一社)日本呼吸器学会 )  10 ( 3 ) 245 - 250  2021.05

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北海道における新型コロナウイルス感染症(coronavirus disease 2019:COVID-19)流行の経験を全国の医療従事者と共有し、大病院と診療所/クリニックとの相違を明らかにすることで、今後の診療に役立てることを目的としてアンケート調査を実施した。診療所ではCOVID-19対策における物理的な制約や、経営的な影響、ストレスに感じる項目など、病院とは異なる影響や考え方があることが明らかとなった。今後それぞれの医療現場の立場・状況に応じてCOVID-19に対する方策を検討することの重要性が示唆された。(著者抄録)

臨床応用を目指した肺胞微石症の基礎および治療法の検討

齋藤 充史, 高宮 里奈, 藤谷 直樹, 有木 茂, 黒沼 幸治, 千葉 弘文, 高橋 素子, 高橋 弘毅

日本肺サーファクタント・界面医学会雑誌 ( 日本肺サーファクタント・界面医学会 )  51   32 - 33  2021.03

Characteristics of COVID-19 patients admitted into two hospitals in sapporo, Japan: Analyses and insights from two outbreak waves.

Takeshi Hattori, Atsushi Saito, Hirofumi Chiba, Koji Kuronuma, Masaru Amishima, Daisuke Morinaga, Yasuo Shichinohe, Yasuyuki Nasuhara, Satoshi Konno

Respiratory investigation   59 ( 2 ) 180 - 186  2021.01  [International journal]

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BACKGROUND: Coronavirus disease (COVID-19) emerged in January 2020 in Sapporo city, and the outbreak has shown two peaks. METHODS: A total of 260 COVID-19 patients were enrolled and categorized into three groups according to the pandemic pattern, jobs and situation, and disease severity. We compared clinical characteristics according to these categories. RESULTS: We found two pandemic peaks, and the proportion of patients and health providers who were infected in other hospitals had increased in the latter two periods (period 2: 49.6%, period 3: 32.7%). Particularly, the proportion of infected health providers was 27% in period 2, and they tended to be younger females with a mild condition. Severity of the disease (requirement of oxygen and/or mechanical ventilation) was associated with advanced age, and all the patients who died during admission were over 60 years old. CONCLUSIONS: We reported the temporal dynamics and characteristics of the COVID-19 pandemic in Sapporo city, Japan. This survey from the viewpoint of the hospital provides a new insight into and a better guide for the further management of the COVID-19 pandemic.

DOI PubMed

Acute eosinophilic pneumonia accompanied with COVID-19: a case report.

Koutaro Murao, Atsushi Saito, Koji Kuronuma, Yoshihiro Fujiya, Satoshi Takahashi, Hirofumi Chiba

Respirology case reports   8 ( 9 ) e00683  2020.12  [International journal]

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We report a case of acute eosinophilic pneumonia (AEP) triggered by coronavirus disease 2019 (COVID-19) infection. A 77-year-old man experienced left-sided chest pain and shortness of breath. Reverse transcription-polymerase chain reaction (RT-PCR) for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) revealed a positive result, and he was treated with favipiravir, ciclesonide, and lascufloxacin, but he showed poor improvement. On the other hand, computed tomography (CT) images were atypical for COVID-19 infection, and the elevation of eosinophil was found in blood and the fluid obtained by bronchoscopy. So, we clinically diagnosed this case as AEP. Administration of prednisolone dramatically improved the patient's clinical condition and chest radiograph findings, which were consistent with the clinical course of AEP. This case suggests the importance of considering the complications of AEP when treating patients with COVID-19 infection.

DOI PubMed

Acrolein in cigarette smoke attenuates the innate immune responses mediated by surfactant protein D.

Rina Takamiya, Motoko Takahashi, Toshitaka Maeno, Atsushi Saito, Masaki Kato, Takahiro Shibata, Koji Uchida, Shigeru Ariki, Miyako Nakano

Biochimica et biophysica acta. General subjects   1864 ( 11 ) 129699 - 129699  2020.11  [International journal]

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BACKGROUND: Surfactant proteins (SP) A and D belong to collectin family proteins, which play important roles in innate immune response in the lung. We previously demonstrated that cigarette smoke (CS) increases the acrolein modification of SP-A, thereby impairing the innate immune abilities of this protein. In this study, we focused on the effects of CS and its component, acrolein, on the innate immunity role of another collectin, SP-D. METHODS: To determine whether aldehyde directly affects SP-D, we examined the lungs of mice exposed to CS for 1 week and detected aldehyde-modified SP-D using an aldehyde reactive probe. The structural changes in CS extract (CSE) or acrolein-exposed recombinant human (h)SP-D were determined by western blot, liquid chromatography-electrospray ionization tandem mass spectrometry, and blue native-polyacrylamide gel electrophoresis analyses. Innate immune functions of SP-D were determined by bacteria growth and macrophage phagocytosis. RESULTS: Aldehyde-modified SP-D as well as SP-A was detected in the lungs of mice exposed to CS for 1 week. Exposure of hSP-D to CSE or acrolein induced an increased higher-molecular -weight of hSP-D and acrolein induced modification of five lysine residues in hSP-D. These modifications led to disruption of the multimer structure of SP-D and attenuated its ability to inhibit bacterial growth and activate macrophage phagocytosis. CONCLUSION: CS induced acrolein modification in SP-D, which in turn induced structural and functional defects in SP-D. GENERAL SIGNIFICANCE: These results suggest that CS-induced structural and functional defects in SP-D contribute to the dysfunction of innate immune responses in the lung following CS exposure.

DOI PubMed

高周波凝固法が有効であった多発気管・気管支乳頭腫の1例

宮坂 友紀, 宮島 さつき, 関川 元基, 佐々原 正幸, 小玉 賢太郎, 斎藤 充史, 高橋 守, 黒沼 幸治, 千葉 弘文

気管支学 ( (NPO)日本呼吸器内視鏡学会 )  42 ( 6 ) 575 - 575  2020.11

オシメルチニブからエルロチニブに変更することでEGFR-TKIを継続し得た慢性心不全合併肺腺癌の一例

関川 元基, 宮坂 友紀, 林 智宏, 小玉 賢太郎, 齋藤 充史, 宮島 さつき, 高橋 守, 千葉 弘文

肺癌 ( (NPO)日本肺癌学会 )  60 ( 6 ) 764 - 764  2020.10

治療開始7ヵ月後にParadoxical reactionを来した粟粒結核の1例

今井 優衣, 宮島 さつき, 鎌田 弘毅, 佐々原 正幸, 宮坂 友紀, 林 智弘, 小玉 賢太郎, 吉川 匠, 斎藤 充史, 高橋 守, 千葉 弘文, 高橋 弘毅

日本サルコイドーシス/肉芽腫性疾患学会雑誌 ( 日本サルコイドーシス )  40 ( 1-2 ) 57 - 57  2020.10

肺胞微石症IIb型ナトリウムリン酸共輸送体(Npt2b)欠損マウスを用いた臨床応用に向けた肺胞微石症の病態解析

高宮 里奈, 三木 寿美, 村上 誠, 高橋 弘毅, 齋藤 充史

日本生化学会大会プログラム・講演要旨集 ( (公社)日本生化学会 )  93回   [P - 608]  2020.09

A retrospective analysis of usefulness of impulse oscillometry system in the treatment of asthma.

Hiroyuki Sugawara, Atsushi Saito, Saori Yokoyama, Kazunori Tsunematsu, Hirofumi Chiba, Hiroki Takahashi

Respiratory research   21 ( 1 ) 226 - 226  2020.08  [International journal]

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BACKGROUND: Bronchial asthma (BA) has different phenotypes, and it requires a clinically effective subtype classification system. The impulse oscillometry system (IOS) is an emerging technique device used in respiratory functional tests. However, its efficacy has not been validated. Therefore, this study aimed to assess the relationship between BA and the IOS parameters, and the difference in the therapeutic effects of inhaled corticosteroids (ICSs) among the subtype classifications was evaluated using the IOS. METHODS: Of the 245 patients with bronchial asthma who were screened, 108 were enrolled in this study. These patients were divided based on three subtypes according to the IOS result as follows: central predominant type (n = 34), peripheral predominant type (n = 58), and resistless type (n = 16). Then, the following ICSs were randomly prescribed in daily medical care: coarse-particle ICS (fluticasone propionate [FP]), fine-particle ICS (mometasone furoate [MF]), and moderate-particle ICS (budesonide [BUD]). The treatment effects were assessed using the Asthma Health Questionnaire (AHQ) and the Asthma Control Test (ACT) and were compared among the three subtypes. RESULTS: In the central predominant type, the AHQ score of the MF group was significantly higher than that of the FP group (15.4 vs. 3.6, p < 0.01) and the BUD group (15.4 vs. 8.8, p < 0.05); the ACT score of the FP group was significantly higher than that of the MF and BUD groups (24.3 vs. 21.7, 22.3, respectively, p < 0.05) at 4 weeks after treatment. In the peripheral predominant type, the AHQ score of the FP group was significantly higher than that of the MF group (14.1 vs. 3.4, p < 0.05); the ACT score of the FP group was lower than that of the MF and BUD groups (22.8 vs. 24.6, 24.4, respectively, p < 0.01) at 4 weeks after treatment. CONCLUSIONS: An association was observed between IOS subtype classification and ICS particle size in terms of therapeutic efficacy in BA. This result indicates that the IOS could be an effective tool in the selection of ICS and the evaluation of the BA phenotype.

DOI PubMed

本邦における肺胞微石症の一症例とモデルマウスを用いた病態解析

齋藤 充史, 高宮 里奈, 有木 茂, 黒沼 幸治, 千葉 弘文, 高橋 弘毅

日本呼吸器学会誌 ( (一社)日本呼吸器学会 )  9 ( 増刊 ) 254 - 254  2020.08

METの部位特異的糖鎖構造の解析

齋藤 淳, 横山 早織, 藤谷 直樹, 齋藤 充史, 有木 茂, 千葉 弘文, 高橋 弘毅, 高橋 素子

日本呼吸器学会誌 ( (一社)日本呼吸器学会 )  9 ( 増刊 ) 303 - 303  2020.08

Real-world efficacy of the impulse oscillometry system for the management of bronchial asthma

Hiroyuki Sugawara, Atsushi Saito, Saori Yokoyama, Kazunori Tsunematsu, Hirofumi Chiba, Hiroki Takahashi

   2020.04

DOI

Real-world efficacy of the impulse oscillometry system for the management of bronchial asthma

Hiroyuki Sugawara, Atsushi Saito, Saori Yokoyama, Kazunori Tsunematsu, Hirofumi Chiba, Hiroki Takahashi

   2020.04

DOI

Comparison of therapeutic effects of inhaled corticosteroids on three subtypes of cough variant asthma as classified by the impulse oscillometry system

Hiroyuki Sugawara, Atsushi Saito, Saori Yokoyama, Kazunori Tsunematsu, Hiroki Takahashi

Respiratory Research ( Springer Science and Business Media {LLC} )  20 ( 1 ) 41  2019.12  [Refereed]

DOI PubMed

Insufficient serum L-ficolin is associated with disease presence and extent of pulmonary Mycobacterium avium complex disease.

Kobayashi T, Kuronuma K, Saito A, Ikeda K, Ariki S, Saitou A, Otsuka M, Chiba H, Takahashi S, Takahashi M, Takahashi H

Respiratory research   20 ( 1 ) 224 - 224  2019.10  [Refereed]  [International journal]

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BACKGROUND: The incidence of infectious disease caused by nontuberculous mycobacteria is increasing worldwide. Pulmonary Mycobacterium avium complex (MAC) disease is difficult to treat with chemotherapy, and its mechanism of infection, infection route, disease onset, and severity remain unknown. Ficolins are oligomeric defense lectins. L-ficolin plays an important role in innate immunity. This study's aim was to identify L-ficolin's role in patients with pulmonary MAC disease. METHODS: Between April 2011 and September 2017, 61 Japanese patients with pulmonary MAC disease were seen at our hospital. A control group, comprising 30 healthy individuals, without respiratory disease were enrolled in our study. The relationship between serum L-ficolin levels and disease severity was assessed, and L-ficolin's antibacterial role was examined. RESULTS: Serum L-ficolin levels were significantly lower in patients with pulmonary MAC disease than in healthy subjects (1.69 ± 1.27 μg/ml vs. 3.96 ± 1.42 μg/ml; p < 0.001). The cut-off value, based on receiver operating characteristic (ROC) analysis results, was 2.48 μg/ml (area under the curve (AUC) 0.90, sensitivity and specificity 83.6 and 86.7%, respectively). Serum L-ficolin levels were significantly lower in the patients with nodular bronchiectatic type disease compared with the patients with fibrocavitary type disease and were lower in the high-resolution computed tomography high-scoring group compared with low-scoring group. An in vitro analysis showed that purified recombinant L-ficolin bound to M. avium and its major cell wall component, lipoarabinomannan, in a concentration-dependent manner. In addition, recombinant L-ficolin suppressed M. avium growth in a concentration-dependent manner. CONCLUSIONS: Insufficient serum L-ficolin is associated with disease progression in pulmonary MAC disease, and the level of serum L-ficolin is a possible biomarker. TRIAL REGISTRATION: This study is registered with UMIN ( UMIN000022392 ).

DOI PubMed

ErbB3の糖鎖による物性制御メカニズム

高橋 素子, 加藤 公児, 藤谷 直樹, 斎藤 充史, 和田 芳直, 姚 閔

日本生化学会大会プログラム・講演要旨集 ( (公社)日本生化学会 )  92回   [1T10m - 01]  2019.09

Autoimmune Pulmonary Alveolar Proteinosis Diagnosed after Exposure to a Fire Extinguisher Containing Silica Powder.

Yorozuya T, Ikeda K, Chiba H, Saito A, Kuronuma K, Nishikiori H, Miyajima S, Takahashi M, Yoshikawa T, Takahashi Y, Taya T, Mori Y, Umeda Y, Otsuka M, Moriyama H, Takahashi H

Internal medicine (Tokyo, Japan)   58 ( 14 ) 2067 - 2072  2019.07  [Refereed]  [Domestic journal]

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We herein report a case of autoimmune pulmonary alveolar proteinosis (PAP) diagnosed after one-time exposure to silica powder. Owing to the misuse of a silica-containing fire extinguisher and the inhalation of large amounts of its powder, the patient experienced prolonged cough and visited our hospital. The findings of chest computed tomography and surgical lung biopsy specimens led to the diagnosis of PAP. Interestingly, the presence of anti-GM-CSF antibody was detected; therefore, both autoimmune characteristics and exposure to large amounts of silica may have caused the development of PAP in this patient. This case provides important insight into the mechanisms leading to the onset of PAP.

DOI PubMed

Characterization of distal airway stem-like cells expressing N-terminally truncated p63 and thyroid transcription factor-1 in the human lung.

Tanaka Y, Yamaguchi M, Hirai S, Sumi T, Tada M, Saito A, Chiba H, Kojima T, Watanabe A, Takahashi H, Sakuma Y

Experimental cell research   372 ( 2 ) 141 - 149  2018.11  [Refereed]  [International journal]

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Distal airway stem cells (DASCs) in the mouse lung can differentiate into bronchioles and alveoli. However, it remains unclear whether the same stem cells exist in the human lung. Here, we found that human lung epithelial (HuL) cells, derived from normal, peripheral lung tissue, in monolayer, mostly express both the N-terminally truncated isoform of p63 (∆Np63), a marker for airway basal cells, and thyroid transcription factor-1 (TTF-1), a marker for alveolar epithelial cells, even though these two molecules are usually expressed in a mutually exclusive way. Three-dimensionally cultured HuL cells differentiated to form bronchiole-like and alveolus-like organoids. We also uncovered a few bronchiolar epithelial cells expressing both ∆Np63 and TTF-1 in the human lung, suggesting that these cells are the cells of origin for HuL cells. Taken together, ΔNp63+ TTF-1+ peripheral airway epithelial cells are possibly the human counterpart of mouse DASCs and may offer potential for future regenerative medicine.

DOI PubMed

Response to pneumococcal vaccine in interstitial lung disease patients: Influence of systemic immunosuppressive treatment.

Koji Kuronuma, Hiroyuki Honda, Tessei Mikami, Atsushi Saito, Kimiyuki Ikeda, Mitsuo Otsuka, Hirofumi Chiba, Gen Yamada, Toyotaka Sato, Shin-Ichi Yokota, Hiroki Takahashi

Vaccine   36 ( 33 ) 4968 - 4972  2018.08  [Refereed]  [International journal]

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BACKGROUND: Interstitial lung diseases (ILD) are severe respiratory diseases, and ILD patients are treated with corticosteroid and immunosuppressive agents. However, it is unclear whether these medications influence the response of pneumococcal vaccine. OBJECTIVES: We examined the immunogenicity of pneumococcal vaccines (PPSV23 and PCV13) in ILD patients undergoing immunosuppressive treatment. METHODS: ILD patients who were regularly followed at the outpatient clinic were enrolled. Sera were collected before and 4-8 weeks after vaccination. Serotype-specific immunoglobulin G (IgG) concentrations against pneumococcal serotype 19F were measured by ELISA. RESULTS: IgG concentrations to serotype 19F were increased in all groups in response to the vaccine. Both PCV13 and PPSV23 induced IgG concentrations in patients immunized for the first time. Response rates for the ILD group were comparable with those for the ILD group undergoing corticosteroid therapy. Only idiopathic pulmonary fibrosis patients undergoing immunosuppressive therapy had a significantly lower response.

DOI PubMed

Impaired diversity of the lung microbiome predicts progression of idiopathic pulmonary fibrosis.

Youhei Takahashi, Atsushi Saito, Hirofumi Chiba, Koji Kuronuma, Kimiyuki Ikeda, Tomofumi Kobayashi, Shigeru Ariki, Motoko Takahashi, Yasushi Sasaki, Hiroki Takahashi

Respiratory research   19 ( 1 ) 34 - 34  2018.02  [Refereed]  [International journal]

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BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is the most frequent and severe form of idiopathic interstitial pneumonias. Although IPF has not been thought to be associated with bacterial communities, recent papers reported the possible role of microbiome composition in IPF. The roles of microbiomes in respiratory functions and as clinical biomarkers for IPF remain unknown. In this study, we aim to identify the relationship between the microbial environment in the lung and clinical findings. METHODS: Thirty-four subjects diagnosed with IPF were included in this analysis. The 16S rDNA was purified from bronchoalveolar lavage fluid obtained at the time of diagnosis and analyzed using next-generation sequencing techniques to characterize the bacterial communities. Furthermore, microbiomes from mice with bleomycin-induced lung fibrosis were analyzed. RESULTS: The most prevalent lung phyla were Firmicutes, Proteobacteria and Bacteroidetes. Decreased microbial diversity was found in patients with low forced vital capacity (FVC) and early mortality. Additionally, the diversity and relative abundance of Firmicutes, Streptococcaceae, and Veillonellaceae were significantly associated with FVC, 6-min walk distance, and serum surfactant protein D. Bleomycin-induced lung fibrosis resulted in decrease of diversity and alteration of microbiota in PCoA analysis. These results support the observations in human specimens. CONCLUSIONS: This study identified relationships between specific taxa in BALF and clinical findings, which were also supported by experiments in a mouse model. Our data suggest the possibility that loss of microbial diversity is associated with disease activities of IPF.

DOI PubMed

肺サーファクタントタンパク質Dは変異型EGFRの活性化を阻害し、肺腺がんの進展を抑制する

長谷川 喜弘, 梅田 泰淳, 大塚 満雄, 有木 茂, 高宮 里奈, 齋藤 充史, 高橋 弘毅, 黒木 由夫, 高橋 素子

生命科学系学会合同年次大会 ( 生命科学系学会合同年次大会運営事務局 )  2017年度   [1P - 0948]  2017.12

タバコ煙中のアクロレインが肺サーファクタントタンパク質A(SP-A)の機能や構造に及ぼす影響

高宮 里奈, 内田 浩二, 柴田 貴広, 前野 敏孝, 有木 茂, 長谷川 喜弘, 齊藤 充史, 黒木 由夫, 高橋 素子

生命科学系学会合同年次大会 ( 生命科学系学会合同年次大会運営事務局 )  2017年度   [3P - 1166]  2017.12

Surfactant protein A down-regulates epidermal growth factor receptor by mechanisms different from those of surfactant protein D

Yoshihiro Hasegawa, Motoko Takahashi, Shigeru Ariki, Atsushi Saito, Yasuaki Uehara, Rina Takamiya, Koji Kuronuma, Hirofumi Chiba, Yuji Sakuma, Hiroki Takahashi, Yoshio Kuroki

JOURNAL OF BIOLOGICAL CHEMISTRY ( AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC )  292 ( 45 ) 18565 - 18576  2017.11  [Refereed]

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We recently reported that the lectin surfactant protein D (SP-D) suppresses epidermal growth factor receptor (EGFR) signaling by interfering with ligand binding to EGFR through an interaction between the carbohydrate-recognition domain (CRD) of SP-D and N-glycans of EGFR. Here, we report that surfactant protein A (SP-A) also suppresses EGF signaling in A549 human lung adenocarcinoma cells and in CHOK1 cells stably expressing human EGFR and that SP-A inhibits the proliferation and motility of the A549 cells. Results with I-125-EGF indicated that SP-A interferes with EGF binding to EGFR, and a ligand blot analysis suggested that SP-A binds EGFR in A549 cells. We also found that SP-A directly binds the recombinant extracellular domain of EGFR (soluble EGFR or sEGFR), and this binding, unlike that of SP-D, was not blocked by EDTA, excess mannose, or peptide:N-glycosidase F treatment. We prepared a collagenase-resistant fragment (CRF) of SP-A, consisting of CRD plus the neck domain of SP-A, and observed that CRF directly binds sEGFR but does not suppress EGF-induced phosphorylation of EGFR in or proliferation of A549 cells. These results indicated that SP-A binds EGFR and down-regulates EGF signaling by inhibiting ligand binding to EGFR as well as SP-D. However, unlike for SP-D, SP-A lectin activity and EGFR N-glycans were not involved in the interaction between SP-A and EGFR. Furthermore, our results suggested that oligomerization of SP-A is necessary to suppress the effects of SP-A on EGF signaling.

DOI PubMed

Surfactant protein D inhibits activation of non-small cell lung cancer-associated mutant EGFR and affects clinical outcomes of patients

Y. Umeda, Y. Hasegawa, M. Otsuka, S. Ariki, R. Takamiya, A. Saito, Y. Uehara, H. Saijo, K. Kuronuma, H. Chiba, H. Ohnishi, Y. Sakuma, H. Takahashi, Y. Kuroki, M. Takahashi

ONCOGENE ( NATURE PUBLISHING GROUP )  36 ( 46 ) 6432 - 6445  2017.11  [Refereed]

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Tyrosine kinase inhibitor (TKI)-sensitive and TKI-resistant mutations of epidermal growth factor receptor (EGFR) are associated with lung adenocarcinoma. EGFR mutants were previously shown to exhibit ligand-independent activation. We have previously demonstrated that pulmonary surfactant protein D (SP-D, SFTPD) suppressed wild-type EGFR signaling by blocking ligand binding to EGFR. We herein demonstrate that SFTPD downregulates ligand-independent signaling in cells harboring EGFR mutations such as TKI-sensitive exon 19 deletion (Ex19del) and L858R mutation as well as TKI-resistant T790M mutation, subsequently suppressing cellular growth and motility. Lectin blotting and ligand blotting in lung cancer cell lines suggested that EGFR mutants express oligomannose-type N-glycans and interact with SFTPD directly. Cross-linking assay indicated that SFTPD inhibits ligand-independent dimerization of EGFR mutants. We also demonstrated that SFTPD reduced dimerization-independent phosphorylation of Ex19del and T790M EGFR mutants using point mutations that disrupted the asymmetric dimer interface. It was confirmed that SFTPD augmented the viability-suppressing effects of EGFR-TKIs. Furthermore, retrospective analysis of 121 patients with lung adenocarcinoma to examine associations between serum SFTPD levels and clinical outcome indicated that in TKI-treated patients with lung cancer harboring EGFR mutations, including Ex19del or L858R, high serum SFTPD levels correlated with a lower number of distant metastases and prolonged overall survival and progression-free survival. These findings suggest that SFTPD downregulates both TKI-sensitive and -resistant EGFR mutant signaling, and SFTPD level is correlated with clinical outcome. These findings illustrate the use of serum SFTPD level as a potential marker to estimate the efficacy of EGFR-TKIs.

DOI PubMed

Serum surfactant protein D predicts the outcome of patients with idiopathic pulmonary fibrosis treated with pirfenidone

Kimiyuki Ikeda, Masanori Shiratori, Hirofumi Chiba, Hirotaka Nishikiori, Keiki Yokoo, Atsushi Saito, Yoshihiro Hasegawa, Koji Kuronuma, Mitsuo Otsuka, Gen Yamada, Hiroki Takahashi

RESPIRATORY MEDICINE ( W B SAUNDERS CO LTD )  131   184 - 191  2017.10  [Refereed]

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Background: Idiopathic pulmonary fibrosis (IPF) is a fatal pulmonary disease with poor prognosis. Pirfenidone, the first antifibrotic drug, suppresses the decline in forced vital capacity (FVC) and improves prognosis in some, but not all, patients with IPF; therefore, an indicator for identifying improved outcomes in pirfenidone therapy is desirable. This study aims to clarify whether baseline parameters can be predictors of disease progression and prognosis in patients with IPF treated with pirfenidone. Methods: We retrospectively investigated patients with IPF who started treatment with pirfenidone between December 2008 and November 2014 at the Sapporo Medical University Hospital. Patients treated with pirfenidone for >6 months were enrolled in this study and were observed until November 2015. We investigated the association of clinical characteristics, pulmonary function test results, and blood examination results at the start of pirfenidone with the outcome of patients. Results: Sixty patients were included in this study. In multivariate logistic regression analysis, % predicted FVC and serum surfactant protein (SP)-D levels were predictors of a >10% decline in FVC in the initial 12 months. In the Cox proportional hazards model, these two factors predicted progression-free survival. Pack-years, % predicted diffusing capacity for carbon monoxide, and SP-D levels predicted overall survival. Conclusions: The serum SP-D level was a predictor of disease progression and prognosis in patients with IPF treated with pirfenidone. In addition, this analysis describes the relative usefulness of other clinical parameters at baseline in estimating the prognosis of patients with IPF who are candidates for pirfenidone therapy. (C) 2017 Elsevier Ltd. All rights reserved.

DOI PubMed

Disruption of the structural and functional features of surfactant protein A by acrolein in cigarette smoke

Rina Takamiya, Koji Uchida, Takahiro Shibata, Toshitaka Maeno, Masaki Kato, Yoshiki Yamaguchi, Shigeru Ariki, Yoshihiro Hasegawa, Atsushi Saito, Soichi Miwa, Hiroki Takahashi, Takaaki Akaike, Yoshio Kuroki, Motoko Takahashi

SCIENTIFIC REPORTS ( NATURE PUBLISHING GROUP )  7 ( 1 ) 8304  2017.08  [Refereed]

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The extent to which defective innate immune responses contribute to chronic obstructive pulmonary disease (COPD) is not fully understood. Pulmonary surfactant protein A (SP-A) plays an important role in regulating innate immunity in the lungs. In this study, we hypothesised that cigarette smoke (CS) and its component acrolein might influence pulmonary innate immunity by affecting the function of SP-A. Indeed, acrolein-modified SP-A was detected in the lungs of mice exposed to CS for 1 week. To further confirm this finding, recombinant human SP-A (hSP-A) was incubated with CS extract (CSE) or acrolein and then analysed by western blotting and nanoscale liquid chromatography-matrix-assisted laser desorption/ionisation time-of-flight tandem mass spectrometry. These analyses revealed that CSE and acrolein induced hSP-A oligomerisation and that acrolein induced the modification of six residues in hSP-A: His39, His116, Cys155, Lys180, Lys221, and Cys224. These modifications had significant effects on the innate immune functions of hSP-A. CSE- or acrolein-induced modification of hSP-A significantly decreased hSP-A's ability to inhibit bacterial growth and to enhance macrophage phagocytosis. These findings suggest that CS-induced structural and functional defects in SP-A contribute to the dysfunctional innate immune responses observed in the lung during cigarette smoking.

DOI PubMed

Mitogenic stimulation accelerates influenza-induced mortality by increasing susceptibility of alveolar type II cells to infection

Nikolaos M. Nikolaidis, John G. Noel, Lori B. Pitstick, Jason C. Gardner, Yasuaki Uehara, Huixing Wu, Atsushi Saito, Kara E. Lewnard, Huan Liu, Mitchell R. White, Kevan L. Hartshorn, Francis X. McCormack

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA ( NATL ACAD SCIENCES )  114 ( 32 ) E6613 - E6622  2017.08  [Refereed]

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Development of pneumonia is the most lethal consequence of influenza, increasing mortality more than 50-fold compared with uncomplicated infection. The spread of viral infection from conducting airways to the alveolar epithelium is therefore a pivotal event in influenza pathogenesis. We found that mitogenic stimulation with keratinocyte growth factor (KGF) markedly accelerated mortality after infectious challenge with influenza A virus (IAV). Coadministration of KGF with IAV markedly accelerated the spread of viral infection from the airways to alveoli compared with challenge with IAV alone, based on spatial and temporal analyses of viral nucleoprotein staining of lung tissue sections and dissociated lung cells. To better define the temporal relationship between KGF administration and susceptibility to IAV infection in vivo, we administered KGF 120, 48, 24, and 0 h before intrapulmonary IAV challenge and assessed the percentages of proliferating and IAV-infected, alveolar type II (AECII) cells in dispersed lung cell populations. Peak AECII infectivity coincided with the timing of KGF administration that also induced peak AECII proliferation. AECII from mice that were given intrapulmonary KGF before isolation and then infected with IAV ex vivo exhibited the same temporal pattern of proliferation and infectious susceptibility. KGF-induced increases in mortality, AECII proliferation, and enhanced IAV susceptibility were all reversed by pretreatment of the animals with the mTOR inhibitor rapamycin before mitogenic stimulation. Taken together, these data suggest mTOR signalingdependent, mitogenic conditioning of AECII is a determinant of host susceptibility to infection with IAV.

DOI PubMed

Surfactant Protein A Inhibits Growth and Adherence of Uropathogenic Escherichia coli To Protect the Bladder from Infection

Jiro Hashimoto, Motoko Takahashi, Atsushi Saito, Masaki Murata, Yuichiro Kurimura, Chiaki Nishitani, Rina Takamiya, Yasuaki Uehara, Yoshihiro Hasegawa, Yoshiki Hiyama, Norimasa Sawada, Satoshi Takahashi, Naoya Masumori, Yoshio Kuroki, Shigeru Ariki

JOURNAL OF IMMUNOLOGY ( AMER ASSOC IMMUNOLOGISTS )  198 ( 7 ) 2898 - 2905  2017.04  [Refereed]

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Surfactant protein A (SP-A) is a multifunctional host defense collectin that was first identified as a component of pulmonary surfactant. Although SP-A is also expressed in various tissues, including the urinary tract, its innate immune functions in nonpulmonary tissues are poorly understood. In this study, we demonstrated that adherence of uropathogenic Escherichia coli (UPEC) to the bladder was enhanced in SP-A-deficient mice, which suggests that SP-A plays an important role in innate immunity against UPEC. To understand the innate immune functions of SP-A in detail, we performed in vitro experiments. SP-A directly bound to UPEC in a Ca2+-dependent manner, but it did not agglutinate UPEC. Our results suggest that a bouquet-like arrangement seems unsuitable to agglutinate UPEC. Meanwhile, SP-A inhibited growth of UPEC in human urine. Furthermore, the binding of SP-A to UPEC decreased the adherence of bacteria to urothelial cells. These results indicate that direct action of SP-A on UPEC is important in host defense against UPEC. Additionally, adhesion of UPEC to urothelial cells was decreased when the cells were preincubated with SP-A. Adhesion of UPEC to urothelial cells is achieved via interaction between FimH, an adhesin located at bacterial pili, and uroplakin Ia, a glycoprotein expressed on the urothelium. SP-A directly bound to uroplakin Ia and competed with FimH for uroplakin Ia binding. These results lead us to conclude that SP-A plays important roles in host defense against UPEC.

DOI PubMed

Surfactant protein A (SP-A) and SP-A-derived peptide attenuate chemotaxis of mast cells induced by human beta-defensin 3

Yasuaki Uehara, Motoko Takahashi, Masaki Murata, Atsushi Saito, Rina Takamiya, Yoshihiro Hasegawa, Koji Kuronuma, Hirofumi Chiba, Jiro Hashimoto, Norimasa Sawada, Hiroki Takahashi, Yoshio Kuroki, Shigeru Ariki

BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS ( ACADEMIC PRESS INC ELSEVIER SCIENCE )  485 ( 1 ) 107 - 112  2017.03  [Refereed]

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Human beta-defensin 3 (hBD3) is known to be involved in mast cell activation. However, molecular mechanisms underlying the regulation of hBD3-induced mast cell activation have been poorly understood. We previously reported that SP-A and SP-A-derived peptide 01 (SAP01) regulate the function of hBD3. In this study, we focused on the effects of SP-A and SAP01 on the activation of mast cells induced by hBD3. SAP01 directly bound to hBD3. Mast cell-mediated vascular permeability and edema in hBD3 administered rat ears were decreased when injected with SP-A or SAP01. Compatible with the results in rat ear model, both SP-A and SAP01 inhibited hBD3-induced chemotaxis of mast cells in vitro. Direct interaction between SP-A or SAP01 and hBD3 seemed to be responsible for the inhibitory effects on chemotaxis. Furthermore, SAP01 attenuated hBD3-induced accumulation of mast cells and eosinophils in tracheas of the OVA-sensitized inflammatory model. SP-A might contribute to the regulation of inflammatory responses mediated by mast cells during infection. (C) 2017 Elsevier Inc. All rights reserved.

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非HIV患者におけるST合剤使用困難ニューモシスチス肺炎に対するアトバコンの使用経験

小林 智史, 齊藤 充史, 錦織 博貴, 黒沼 幸治, 高橋 弘毅

感染症学雑誌 ( (一社)日本感染症学会 )  91 ( 1 ) 93 - 93  2017.01

Pulmonary Alveolar Microlithiasis

Atsushi Saito, Francis X. McCormack

CLINICS IN CHEST MEDICINE ( W B SAUNDERS CO-ELSEVIER INC )  37 ( 3 ) 441 - +  2016.09  [Refereed]

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Pulmonary alveolar microlithiasis (PAM) is a genetic lung disorder that is characterized by the accumulation of calcium phosphate deposits in the alveolar spaces of the lung. Mutations in the type II sodium phosphate cotransporter, NPT2b, have been reported in patients with PAM. PAM progresses gradually, often producing incremental dyspnea on exertion, desaturation in young adulthood, and respiratory insufficiency by late middle age. Treatment remains supportive, including supplemental oxygen therapy. For patients with end-stage disease, lung transplantation is available as a last resort. The recent development of a laboratory animal model has revealed several promising treatment approaches for future trials.

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Keratinocyte growth factor supports pulmonary innate immune defense through maintenance of alveolar antimicrobial protein levels and macrophage function

Jason C. Gardner, Huixing Wu, John G. Noel, Benjamin J. Ramser, Lori Pitstick, Atsushi Saito, Nikolaos M. Nikolaidis, Francis X. McCormack

AMERICAN JOURNAL OF PHYSIOLOGY-LUNG CELLULAR AND MOLECULAR PHYSIOLOGY ( AMER PHYSIOLOGICAL SOC )  310 ( 9 ) L868 - L879  2016.05  [Refereed]

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Keratinocyte growth factor (KGF) is an epithelial mitogen that has been reported to protect the lungs from a variety of toxic and infectious insults. In prior studies we found that recombinant human KGF accelerates clearance of bacteria from the murine lung by augmenting the function of alveolar macrophages (AM). In this study we tested the hypothesis that endogenous KGF plays a role in the maintenance of innate pulmonary defense against gram-negative bacterial infections. KGF-deficient mice exhibited delayed clearance of Escherichia coli from the lungs, attenuated phagocytosis by AM, and decreased antimicrobial activity in bronchoalveolar lavage (BAL) fluid, due in part to reductions in levels of surfactant protein A, surfactant protein D, and lysozyme. These immune deficits were accompanied by lower alveolar type II epithelial cell counts and reduced alveolar type II epithelial cell expression of collectin and lysozyme genes on a per cell basis. No significant between-group differences were detected in selected inflammatory cytokines or BAL inflammatory cell populations at baseline or after bacterial challenge in the wild-type and KGF-deficient mice. A single intranasal dose of recombinant human KGF reversed defects in bacterial clearance, AM function, and BAL fluid antimicrobial activity. We conclude that KGF supports alveolar innate immune defense through maintenance of alveolar antimicrobial protein levels and functions of AM. Together these data demonstrate a role for endogenous KGF in maintenance of normal pulmonary innate immune function.

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Modeling pulmonary alveolar microlithiasis by epithelial deletion of the Npt2b sodium phosphate cotransporter reveals putative biomarkers and strategies for treatment

Atsushi Saito, Nikolaos M. Nikolaidis, Hassane Amlal, Yasuaki Uehara, Jason C. Gardner, Kathleen LaSance, Lori B. Pitstick, James P. Bridges, Kathryn A. Wikenheiser-Brokamp, Dennis W. McGraw, Jason C. Woods, Yves Sabbagh, Susan C. Schiavi, Goksel Altinisik, Marko Jakopovic, Yoshikazu Inoue, Francis X. McCormack

SCIENCE TRANSLATIONAL MEDICINE ( AMER ASSOC ADVANCEMENT SCIENCE )  7 ( 313 ) 313ra181  2015.11  [Refereed]

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Pulmonary alveolar microlithiasis (PAM) is a rare, autosomal recessive lung disorder associated with progressive accumulation of calcium phosphate microliths. Inactivating mutations in SLC34A2, which encodes the NPT2b sodium-dependent phosphate cotransporter, has been proposed as a cause of PAM. We show that epithelial deletion of Npt2b in mice results in a progressive pulmonary process characterized by diffuse alveolar microlith accumulation, radiographic opacification, restrictive physiology, inflammation, fibrosis, and an unexpected alveolar phospholipidosis. Cytokine and surfactant protein elevations in the alveolar lavage and serum of PAM mice and confirmed in serum from PAM patients identify serum MCP-1 (monocyte chemotactic protein 1) and SP-D (surfactant protein D) as potential biomarkers. Microliths introduced by adoptive transfer into the lungs of wild-typemice produce marked macrophage-rich inflammation and elevation of serum MCP-1 that peaks at 1 week and resolves at 1 month, concomitant with clearance of stones. Microliths isolated by bronchoalveolar lavage readily dissolve in EDTA, and therapeutic whole-lung EDTA lavage reduces the burden of stones in the lungs. A low-phosphate diet prevents microlith formation in young animals and reduces lung injury on the basis of reduction in serum SP-D. The burden of pulmonary calcium deposits in established PAM is also diminished within 4 weeks by a low-phosphate diet challenge. These data support a causative role for Npt2b in the pathogenesis of PAM and the use of the PAM mouse model as a preclinical platform for the development of biomarkers and therapeutic strategies.

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Surfactant protein D suppresses lung cancer progression by downregulation of epidermal growth factor signaling

Y. Hasegawa, M. Takahashi, S. Ariki, D. Asakawa, M. Tajiri, Y. Wada, Y. Yamaguchi, C. Nishitani, R. Takamiya, A. Saito, Y. Uehara, J. Hashimoto, Y. Kurimura, H. Takahashi, Y. Kuroki

ONCOGENE ( NATURE PUBLISHING GROUP )  34 ( 7 ) 838 - 845  2015.02  [Refereed]

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Surfactant protein D (SP-D) is a member of the collectin family that has an important role in maintaining pulmonary homeostasis. In this study, we demonstrated that SP-D inhibited the proliferation, migration and invasion of A549 human lung adenocarcinoma cells. We found that SP-D suppressed epidermal growth factor (EGF) signaling in A549 cells, H441 human lung adenocarcinoma cells and human EGF receptor (EGFR) stable expression CHO-K1 cells. A binding study using I-125-EGF demonstrated that SP-D downregulated the binding of EGF to EGFR. A ligand blot indicated that SP-D bound to EGFR, and a lectin blot suggested that EGFR in A549 cells had both high-mannose type and complex type N-glycans. We purified the recombinant extracellular domain of EGFR (soluble EGFR=soluble EGFR (sEGFR)), and demonstrated that SP-D directly bound to sEGFR in a Ca2+-dependent manner. The binding of SP-D to sEGFR was suppressed by EDTA, mannose or N-glycopeptidase F treatment. Mass spectrometric analysis indicated that N-glycans in domain III of EGFR were of a high-type. These data suggest that SP-D reduces EGF binding to EGFR through the interaction between the carbohydrate recognition domain of SP-D and N-glycans of EGFR, and downregulates EGF signaling. Our finding suggests the novel type of regulation system of EGF signaling involving lectin-to-carbohydrate interaction and downregulation of ligand binding.

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Surfactant protein D suppresses lung cancer progression by downregulation of epidermal growth factor signalling (vol 34, pg 838, 2014)

Hasegawa Y, Takahashi M, Ariki S, Asakawa D, Tajiri M, Wada Y, Yamaguchi Y, Nishitani C, Takamiya R, Saito A, Uehara Y, Hashimoto J, Kurimura Y, Takahashi H, Kuroki Y

Oncogene   34 ( 32 ) 4285 - 4286  2015  [Refereed]

DOI

Surfactant Protein D Inhibits Adherence of Uropathogenic Escherichia coli to the Bladder Epithelial Cells and the Bacterium-induced Cytotoxicity A POSSIBLE FUNCTION IN URINARY TRACT

Yuichiro Kurimura, Chiaki Nishitani, Shigeru Ariki, Atsushi Saito, Yoshihiro Hasegawa, Motoko Takahashi, Jiro Hashimoto, Satoshi Takahashi, Taiji Tsukamoto, Yoshio Kuroki

JOURNAL OF BIOLOGICAL CHEMISTRY ( AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC )  287 ( 47 ) 39578 - 39588  2012.11  [Refereed]

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The adherence of uropathogenic Escherichia coli (UPEC) to the host urothelial surface is the first step for establishing UPEC infection. Uroplakin Ia (UPIa), a glycoprotein expressed on bladder urothelium, serves as a receptor for FimH, a lectin located at bacterial pili, and their interaction initiates UPEC infection. Surfactant protein D (SP-D) is known to be expressed on mucosal surfaces in various tissues besides the lung. However, the functions of SP-D in the non-pulmonary tissues are poorly understood. The purposes of this study were to investigate the possible function of SP-D expressed in the bladder urothelium and the mechanisms by which SP-D functions. SP-D was expressed in human bladder mucosa, and its mRNA was increased in the bladder of the UPEC infection model in mice. SP-D directly bound to UPEC and strongly agglutinated them in a Ca2+-dependent manner. Co-incubation of SP-D with UPEC decreased the bacterial adherence to 5637 cells, the human bladder cell line, and the UPEC-induced cytotoxicity. In addition, preincubation of SP-D with 5637 cells resulted in the decreased adherence of UPEC to the cells and in a reduced number of cells injured by UPEC. SP-D directly bound to UPIa and competed with FimH for UPIa binding. Consistent with the in vitro data, the exogenous administration of SP-D inhibited UPEC adherence to the bladder and dampened UPEC-induced inflammation in mice. These results support the conclusion that SP-D can protect the bladder urothelium against UPEC infection and suggest a possible function of SP-D in urinary tract.

DOI PubMed

Pulmonary Surfactant Protein A Protects Lung Epithelium from Cytotoxicity of Human beta-Defensin 3

Atsushi Saito, Shigeru Ariki, Hitoshi Sohma, Chiaki Nishitani, Kanako Inoue, Nobutaka Ebata, Motoko Takahashi, Yoshihiro Hasegawa, Koji Kuronuma, Hiroki Takahashi, Yoshio Kuroki

JOURNAL OF BIOLOGICAL CHEMISTRY ( AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC )  287 ( 18 ) 15034 - 15043  2012.04  [Refereed]

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Defensins are important molecules in the innate immune system that eliminate infectious microbes. They also exhibit cytotoxicity against host cells in higher concentrations. The mechanisms by which hosts protect their own cells from cytotoxicity of defensins have been poorly understood. We found that the cytotoxicity of human beta-defensin 3 (hBD3) against lung epithelial cells was dose-dependently attenuated by pulmonary surfactant protein A (SP-A), a collectin implicated in host defense and regulation of inflammatory responses in the lung. The direct interaction between SP-A and hBD3 may be an important factor in decreasing this cytotoxicity because preincubation of epithelial cells with SP-A did not affect the cytotoxicity. Consistent with in vitro analysis, intratracheal administration of hBD3 to SP-A(-/-) mice resulted in more severe tissue damage compared with that in WT mice. These data indicate that SP-A protects lung epithelium from tissue injury caused by hBD3. Furthermore, we found that the functional region of SP-A lies within Tyr(161)-Lys(201). Synthetic peptide corresponding to this region, tentatively called SP-A Y161-G200, also inhibited cytotoxicity of hBD3 in a dose-dependent manner. The SP-A Y161-G200 is a candidate as a therapeutic reagent that prevents tissue injury during inflammation.

DOI PubMed

肺コレクチンはレジオネラ感染により誘導されるオートファジーを抑制する

齋藤 充史, 有木 茂, 長谷川 喜弘, 栗村 雄一郎, 西谷 千明, 高橋 素子, 高橋 弘毅, 黒木 由夫

日本肺サーファクタント・界面医学会雑誌 ( 日本肺サーファクタント・界面医学会 )  42   32 - 32  2011.10

Pulmonary Collectins Play Distinct Roles in Host Defense against Mycobacterium avium

Shigeru Ariki, Takashi Kojima, Shinsei Gasa, Atsushi Saito, Chiaki Nishitani, Motoko Takahashi, Takeyuki Shimizu, Yuichiro Kurimura, Norimasa Sawada, Nobuhiro Fujii, Yoshio Kuroki

JOURNAL OF IMMUNOLOGY ( AMER ASSOC IMMUNOLOGISTS )  187 ( 5 ) 2586 - 2594  2011.09  [Refereed]

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Pulmonary collectins, surfactant protein A (SP-A) and surfactant protein D (SP-D), play important roles in the innate immunity of the lung. Mycobacterium avium is one of the well-known opportunistic pathogens that can replicate within macrophages. We examined the effects of pulmonary collectins in host defense against M. avium infection achieved via direct interaction between bacteria and collectins. Although both pulmonary collectins bound to M. avium in a Ca(2+)-dependent manner, these collectins revealed distinct ligand-binding specificity and biological activities. SP-A and SP-D bound to a methoxy group containing lipid and lipoarabinomannan, respectively. Binding of SP-D but not SP-A resulted in agglutination of M. avium. A chimeric protein with the carbohydrate recognition domain of SP-D, which chimera revealed a bouquet-like arrangement similar to SP-A, also agglutinated M. avium. The ligand specificity of the carbohydrate recognition domain of SP-D seems to be necessary for agglutination activity. The binding of SP-A strongly inhibited the growth of M. avium in culture media. Although pulmonary collectins did not increase membrane permeability of M. avium, they attenuated the metabolic rate of the bacteria. Observations under a scanning electron microscope revealed that SP-A almost completely covers bacterial surfaces, whereas SP-D binds to certain areas like scattered dots. These observations suggest that a distinct binding pattern of collectins correlates with the difference of their biological activities. Furthermore, the number of bacteria phagocytosed by macrophages was significantly increased in the presence of SP-D. These data indicate that pulmonary collectins play critical roles in host defense against M. avium. The Journal of Immunology, 2011, 187: 2586-2594.

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Pulmonary Collectins Protect Macrophages against Pore-forming Activity of Legionella pneumophila and Suppress Its Intracellular Growth

Kaku Sawada, Shigeru Ariki, Takashi Kojima, Atsushi Saito, Masami Yamazoe, Chiaki Nishitani, Takeyuki Shimizu, Motoko Takahashi, Hiroaki Mitsuzawa, Shin-ichi Yokota, Norimasa Sawada, Nobuhiro Fujii, Hiroki Takahashi, Yoshio Kuroki

JOURNAL OF BIOLOGICAL CHEMISTRY ( AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC )  285 ( 11 ) 8434 - 8443  2010.03  [Refereed]

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Pulmonary collectins, surfactant proteins A (SP-A) and D (SP-D), play important roles in innate immunity of the lung. Legionella pneumophila is a bacterial respiratory pathogen that can replicate within macrophages and causes opportunistic infections. L. pneumophila possesses cytolytic activity, resulting from insertion of pores in the macrophage membrane upon contact. We examined whether pulmonary collectins play protective roles against L. pneumophila infection. SP-A and SP-D bound to L. pneumophila and its lipopolysaccharide (LPS) and inhibited the bacterial growth in a Ca(2+)-dependent manner. The addition of LPS in the culture blocked the inhibitory effects on L. pneumophila growth by the collectins, indicating the importance of LPS-collectin interaction. When differentiated THP-1 cells were infected with L. pneumophila in the presence of SP-A and SP-D, the number of permeable cells was significantly decreased, indicating that pulmonary collectins inhibit pore-forming activity of L. pneumophila. The number of live bacteria within the macrophages on days 1-4 after infection was significantly decreased when infection was performed in the presence of pulmonary collectins. The phagocytosis experiments with the pH-sensitive dye-labeled bacteria revealed that pulmonary collectins promoted bacterial localization to an acidic compartment. In addition, SP-A and SP-D significantly increased the number of L. pneumophila co-localized with LAMP-1. These results indicate that pulmonary collectins protect macrophages against contact-dependent cytolytic activity of L. pneumophila and suppress intracellular growth of the phagocytosed bacteria. The promotion of lysosomal fusion with Legionella-containing phagosomes constitutes a likely mechanism of L. pneumophila growth suppression by the collectins.

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