| 研究課題/領域番号 |
20K10425
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| 研究機関 | 北海道大学 |
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研究代表者 |
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| 研究分担者 |
荒木 敦子 北海道大学, 環境健康科学研究教育センター, 特任教授 (00619885)
今野 哲 北海道大学, 医学研究院, 教授 (20399835)
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| 研究期間 (年度) |
2020-04-01 – 2023-03-31
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| キーワード | Asthma / Obesity / Adults and children / Airway inflammation / Club cell protein (CC16) |
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| 研究実績の概要 |
Background and Aim: Club cell protein (CC16), also known as CC10, is expressed primarily in the respiratory tract and is a potent anti-inflammatory agent that protects the airway from inflammation. Given that CC16 is a major anti-inflammatory protein in the airway, coupled with the relationship between CC16 and obesity and asthma, we hypothesized that CC16 is involved in the pathogenesis of obese asthma phenotype.
Methods: We measured serum CC16 in asthma patients by ELISA (n=206). The recruitment of Japanese patients with asthma has been previously described (Konno et al. 2018).The diagnosis of severe asthma was based on the American Thoracic Society (ATS) criteria for refractory asthma in 2000, with slight modifications (Konno et al. 2018, Goudarzi et al. 2019). A total of 206 participants (127 with severe asthma and 79 with mild-to-moderate asthma) were included in this study.
Results: The serum CC16 levels in asthmatic patients were significantly lower in females vs. males, and in patients with severe asthma vs. non-severe asthma. In our primary data analysis, we found an inverse correlation between BMI and serum CC16 in asthmatic patients. Additionally, I found an inverse significant association of BMI tertile with serum CC16 in crude model as well as two adjusted models.
Conclusion and future plan: Obesity may reduce CC16 protein which is one of main anti-inflammatory proteins in the airway. For extension of the potential effects of obesity on CC16 levels in general populations, we also examine association between BMI and circulating CC16 levels in children.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
1: 当初の計画以上に進展している
理由
Currently, we have two stablished cohort studies; i) Adult asthma cohort, ii) a birth cohort. Therefore, the recruitment of participants and biospecimen collection have previously performed. We have collected sociodemographic characteristics of the participants. Serum or plasma samples were stored at －80 °C until assayed for CC16.
For allergic condition assessment in children, follow-up questionnaires were distributed to children aged 1, 2, 4, 7 and 9-11 years old, which included questions pertaining to wheeze, rhinitis and eczema from the “International Study of Asthma and Allergies in Childhood” (ISAAC) questionnaires. Currently, we have information on outcome assessment of allergic diseases in children with samples size of 428 mother-child pairs, in addition to T helper 2 biomarkers (blood eosinophils, serum IgE, and fractional exhaled nitric oxide). Also, information on anthropometric measures, doctor-diagnosis of asthma, and confounders are extracted from the same questionnaires. Therefore, we have progressed in our epidemiological section of our project.
However, we have faced some difficulties last year. For providing strong evidence regarding causal relationship between BMI and CC16, we need to do in vivo studies (not only epidemiological studies) which is a time- and energy- consuming process and we need to collaborating with international groups to receive Cc16 knockout mice and hire or ask some technicians to help us to use mice models. We are designing detailed mice studies to get valid and convincing data in the future, supporting our epidemiological data.
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| 今後の研究の推進方策 |
1) Epidemiological studies: We are going to measure CC16 in cord blood. After this measurement, because of our smooth progress in human studies, I will be able to do several statistical analysis in our birth cohort. I will assess assocaition of BMI and circulatory CC16 with cross-sectional and prospective approach. I also examine association of CC16 with asthma phenotypes and Th2 biomarkers in children. Finally, I will examine association of early life CC16 with development of obese asthma.
2) Animal studies: One strategy is using Cc16 knockout mice; however, we do not have it and need to ask a foreign university or institute for an international collaboration. C57BL/6 Cc16-/- and wild-type mice will be used (n=10 for each group). Wild-type and Cc16-/- mice randomly will be divided into two subgroups given as libitum access to normal chow or a high fat diet for 12 weeks. Therefore, we will have four mice groups (n=5 for each subgroup): wild-type mice with normal or high-fat diet, Cc16-/- mice with normal or high-fat diet. After scarification, inflammatory cells will be quantified in bronchoalveolar lavage (BAL) fluid. Eosinophilic inflammatory biomarkers (IL-4, IL-5, and IL-13) will be examined in BAL fluid by ELISA (R&D Systems). Small airway remodeling will be examined on lung sections examining fibrosis and immunostained for type-I collagen and fibronectin. Additionally, small airways will be immunostained for CC16 and MUC5AC proteins. Number of cells expressing target proteins in randomly selected fields will be manually counted to assess percentage of positive cells.
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| 次年度使用額が生じた理由 |
In FY 2020, I could get an internal grant from Hokkaido university and could pay for buying ELISA kits. Also, recruitment of children, distribution of ISAAC questionnaires, and blood samples have been performed by Hokkaido university Center for Environmental and Health Sciences. Therefore, we did not use significant amount of budget in FY 2020. However, we are going to measure several biomarkers in children and perform animal studies in FY 2021. Accordingly, we are going to use significant part of the provided grant in this FY.
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