González Roldán Nestor, Lunding Lars P, Fujimoto Yukari, Düpow Sylvia, Schwudke Dominik, Wegmann Michael, Duda Katarzyna A
Research Group of Biofunctional Metabolites and Structures, Research Center Borstel, Leibniz Lung Center, Research Center Borstel, Airway Research North (ARCN), German Center for Lung Research (DZL), Borstel, Germany.
Research Group of Lung Immunology, Research Center Borstel, Leibniz Lung Center, Research Center Borstel, Airway Research North (ARCN), German Center for Lung Research (DZL), Borstel, Germany.
Front Immunol. 2025 Jun 17;16:1532773. doi: 10.3389/fimmu.2025.1532773. eCollection 2025.
Grass pollen triggers nearly 30% of bronchial allergic asthma cases. While most Q8 research focuses on pollen allergens, pollen lipids may also influence allergic reactions. Previous studies demonstrated that Timothy grass (TG, Phleum pratense) lipids, such as phytoprostanes, can activate immune cells, promoting pro-allergic responses. However, the role of water-insoluble pollen glycolipids in allergic airway inflammation remains unclear. Thus, this study aimed to isolate and characterize glycolipids from TG pollen and evaluate their bioactivity in allergic airway inflammation.
Lipids were extracted from the water-insoluble pollen fraction, separated by silica gel, and fractionated by HPLC. GC-MS, HR ESI-MS, and NMR confirmed the presence of di-galactosyldiacylglycerol (DGDG). The biological activity of fractions containing DGDG (DGDG-3 and DGDG-4) and synthetic DGDG variants was tested in vitro in murine and human cell systems and in vivo in mice.
Fraction 4 induced strong proliferation of murine NKT cells and upregulated CD69 expression in human NKT cells. Synthetic DGDG variants (DGDG-1, DGDG-2, and DGDG-3) with defined acylation profiles stimulated robust NKT-cell proliferation, with DGDG-2 and DGDG-3 increasing IL-13 production, one of the key Th2 cytokines. In vivo, only these variants caused lung inflammation marked by eosinophil infiltration but did not increase airway resistance.
This study reveals for the first time the structure-dependent role of DGDG of TG pollen grains in immune cell recognition in the context of allergic inflammation. Our data may pave the way for therapies targeting lipid components in combination with protein allergens.
草花粉引发了近30%的支气管过敏性哮喘病例。虽然大多数研究集中在花粉过敏原上，但花粉脂质也可能影响过敏反应。先前的研究表明，梯牧草（TG，早熟禾）脂质，如植物前列腺素，可激活免疫细胞，促进过敏反应。然而，水不溶性花粉糖脂在过敏性气道炎症中的作用仍不清楚。因此，本研究旨在从TG花粉中分离和鉴定糖脂，并评估其在过敏性气道炎症中的生物活性。
从水不溶性花粉组分中提取脂质，通过硅胶分离，并用高效液相色谱法分级分离。气相色谱-质谱联用仪（GC-MS）、高分辨电喷雾电离质谱（HR ESI-MS）和核磁共振（NMR）证实了二半乳糖基二酰基甘油（DGDG）的存在。在小鼠和人类细胞系统中体外测试了含有DGDG的组分（DGDG-3和DGDG-4）以及合成DGDG变体的生物活性，并在小鼠体内进行了测试。
组分4诱导小鼠NKT细胞强烈增殖，并上调人NKT细胞中CD69的表达。具有特定酰化谱的合成DGDG变体（DGDG-1、DGDG-2和DGDG-3）刺激NKT细胞强劲增殖，其中DGDG-2和DGDG-3增加白细胞介素-13的产生，白细胞介素-13是关键的Th2细胞因子之一。在体内，只有这些变体引起以嗜酸性粒细胞浸润为特征的肺部炎症，但并未增加气道阻力。
本研究首次揭示了TG花粉粒中DGDG在过敏性炎症背景下免疫细胞识别中的结构依赖性作用。我们的数据可能为针对脂质成分与蛋白质过敏原联合治疗的方法铺平道路。
