Defining the structural and functional properties of select agricultural fibers underlying their immunomodulatory actions

定义精选农业纤维的免疫调节作用的结构和功能特性

• 批准号: RGPIN-2022-03612
• 负责人: Armstrong, Heather
• 金额: $ 2.04万
• 依托单位: University of Manitoba
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=757670
• 关键词: Defining; structural; functional; properties; select

The long-term goal of this program is to define the physiologically relevant microbe-mediated fermentation pathways for select fibers of interest, sourced from different common agricultural products and to uncover the biochemical mechanisms underlying fiber-associated immunomodulatory pathways in various environmental settings. Fibers are nondigestible carbohydrates that rely on fermentation by intestinal microorganisms (bacteria and fungi) for their decomposition into byproducts that can be utilized by human cells (e.g., short chain fatty acids). Our previous work showed specific dysbiotic microbial communities (altered microbe abundance/diversity), and more significantly, altered microbe functions (enzymes) were associated with reduced ß-fructan fibre fermentation. This altered fermentation was associated with reduced production of SCFA and increased immunomodulatory interactions of unfermented ß-fructans with leukocytes (macrophages, T cells, and neutrophils), particularly through Th17 cellular pathways. Our preliminary findings suggest that the structure of these fibers, which differs between fiber subtypes and the agricultural source from which they are isolated, plays a role in their fermentability and in leukocyte response processes, as the degree of polymerization (DP; length of the fiber) was associated with inflammasome (NLRP3:IL-1ß) activation; higher DP fibres increased cytokine secretion and expression of inflammasome genes (e.g., IL-1ß, IL-23). The short-term objectives of the proposed research are: (1) profile the structural features (e.g., phenolic content, degree polymerization) of dietary fibres (e.g., ß-glucans, galatooligosaccharides, inulins); fibres will be either purchased or extracted from agricultural food sources. Structural features will be correlated with the cellular pathways of leukocyte responses to each of the dietary fibre compounds, examined using mesoscale discovery and ELISA; (2) identify gut microenvironment factors (e.g., pH, metabolites) involved in regulating the functions (enzymes) of microbiota cultures that mediate their fibre fermentation activities; (3) reveal the role of specific microbial enzymes in mediating fibre fermentation processes; and (4) provide mechanistic insight into how fibre-microbe interactions impact leukocyte response (modulation of inflammasome pathways) using targeted microscopy and pathway analysis (qPCR, western blotting, ELISA). This program will advance our fundamental understanding of the role of dietary fibre physical properties in regulating interactions with leukocytes and fermentative microbes while providing multidisciplinary training opportunities for HQP in food chemistry, microbiology and immunology. Our work will aid to improve understanding of interactions that occur, between environmental factors (microenvironment and agricultural products) and leukocyte cell populations that reside in the intestinal mucosa, the physiological site of fibre fermentation.

该计划的长期目标是为来自不同常见农产品的特定纤维定义生理相关的微生物介导的发酵途径，并揭示各种环境条件下纤维相关免疫调节途径的生化机制。不可消化的碳水化合物依靠肠道微生物（细菌和真菌）的发酵分解成可供人体细胞利用的副产品（例如，短链脂肪酸）。特定的失调微生物群落（改变微生物丰度/多样性），更重要的是，改变微生物功能（酶）与β-果聚糖纤维发酵减少有关，这种发酵与 SCFA 产量减少和未发酵 β-果聚糖的免疫调节相互作用增加有关。与白细胞（巨噬细胞、T 细胞和中性粒细胞）的相互作用，特别是通过 Th17 细胞途径，我们的初步研究结果表明这些细胞的结构。纤维在纤维亚型和分离它们的农业来源之间有所不同，在其发酵性和白细胞反应过程中发挥着作用，因为聚合度（DP；纤维长度）与炎性体相关（NLRP3：IL） -1ß）激活；较高的 DP 纤维增加细胞因子分泌和炎性体基因（例如 IL-1ß、IL-23）的表达。 (1) 分析膳食纤维（例如β-葡聚糖、低聚半乳糖、菊粉）的结构特征（例如，酚含量、聚合度）；纤维将从农业食品来源中购买或提取。使用中尺度发现和 ELISA 检查白细胞对每种膳食纤维化合物反应的细胞途径（2）识别肠道微环境因素； （例如，pH、代谢物）参与调节微生物群培养物的功能（酶），从而介导纤维发酵活动；（3）揭示特定微生物酶在介导纤维发酵过程中的作用；以及（4）提供关于如何介导纤维发酵过程的机制见解；使用靶向显微镜和通路分析（qPCR、蛋白质印迹、ELISA）研究纤维-微生物相互作用影响白细胞反应（炎症小体通路的调节）。我们对膳食纤维物理特性在调节与白细胞和发酵微生物相互作用中的作用的基本了解，同时为 HQP 在食品化学、微生物学和免疫学方面提供多学科培训机会，我们的工作将有助于提高对环境因素之间发生的相互作用的理解。微环境和农产品）和驻留在肠粘膜（纤维发酵的生理部位）中的白细胞细胞群。