Faculty of Pharmacy and Pharmaceutical Sciences, Josai University, 1-1 Keyakidai, Sakado, Saitama 350-0295, Japan.
School of Pharmacy, Aichi Gakuin University, 1-100 Kusumoto-cho, Chikusa-ku, Nagoya, Aichi 464-8650, Japan.
Int J Mol Sci. 2024 Aug 10;25(16):8725. doi: 10.3390/ijms25168725.
Galectins are β-galactoside-binding animal lectins involved in various biological functions, such as host defense. Galectin-2 and -3 are members of the galectin family that are expressed in the stomach, including the gastric mucosa and surface mucous cells. Galectin-3 exhibits aggregation and bactericidal activity against in a β-galactoside-dependent manner. We previously reported that galectin-2 has the same activity under neutral pH conditions. In this study, the aggregation activity of galectin-2 was examined under weakly acidic conditions, in which survived. Galectin-2 agglutinated even at pH 6.0, but not at pH 5.0, correlating with its structural stability, as determined using circular dichroism. Additionally, galectin-2 binding to the lipopolysaccharide (LPS) of cultured under weakly acidic conditions was investigated using affinity chromatography and Western blotting. Galectin-2 could bind to LPS containing H type I, a Lewis antigen, in a β-galactoside-dependent manner. In contrast, galectin-3 was structurally more stable than galectin-2 under acidic conditions and bound to LPS containing H type I and Lewis X. In conclusion, galectin-2 and -3 might function cooperatively in the defense against in the stomach under different pH conditions.
半乳糖凝集素是一类能与β-半乳糖苷结合的动物凝集素，参与多种生物学功能，如宿主防御。半乳糖凝集素-2 和 -3 是在胃中表达的半乳糖凝集素家族的成员，包括胃黏膜和表面黏液细胞。半乳糖凝集素-3 以β-半乳糖苷依赖的方式表现出对 的聚集和杀菌活性。我们之前报道过，在中性 pH 条件下，半乳糖凝集素-2 也具有相同的活性。在这项研究中，在酸性条件下（在此条件下 可以存活），研究了半乳糖凝集素-2 的 聚集活性。半乳糖凝集素-2 在 pH 6.0 时可以聚集 ，但在 pH 5.0 时不能聚集，这与其结构稳定性有关，通过圆二色性测定可以确定。此外，还使用亲和层析和 Western blot 研究了半乳糖凝集素-2 在酸性条件下与培养的 的脂多糖 (LPS) 的结合。半乳糖凝集素-2 可以以β-半乳糖苷依赖的方式结合含有 H 型 I（Lewis 抗原）的 LPS。相比之下，在酸性条件下，半乳糖凝集素-3 的结构比半乳糖凝集素-2 更稳定，并且可以结合含有 H 型 I 和 Lewis X 的 LPS。总之，半乳糖凝集素-2 和 -3 可能在不同 pH 条件下协同作用于胃中的防御。
