División de Inmunología, Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, San Luis CP5700, Argentina.
Instituto Multidisciplinario de Investigaciones Biológicas (IMIBIO), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), San Luis C5700, Argentina.
Biomolecules. 2021 Nov 4;11(11):1636. doi: 10.3390/biom11111636.
(Ye) inserts outer proteins (Yops) into cytoplasm to infect host cells. However, in spite of considerable progress, the mechanisms implicated in this process, including the association of Yops with host proteins, remain unclear. Here, we evaluated the functional role of Galectin-1 (Gal1), an endogenous β-galactoside-binding protein, in modulating Yop interactions with host cells. Our results showed that Gal1 binds to Yops in a carbohydrate-dependent manner. Interestingly, Gal1 binding to Yops protects these virulence factors from trypsin digestion. Given that early control of Ye infection involves activation of macrophages, we evaluated the role of Gal1 and YopP in the modulation of macrophage function. Although Gal1 and YopP did not influence production of superoxide anion and/or TNF by Ye-infected macrophages, they coordinately inhibited nitric oxide (NO) production. Notably, recombinant Gal1 (rGal1) did not rescue NO increase observed in macrophages infected with the YopP mutant Ye ∆. Whereas NO induced apoptosis in macrophages, no significant differences in cell death were detected between Gal1-deficient macrophages infected with Ye ∆, and WT macrophages infected with Ye wt. Strikingly, increased NO production was found in WT macrophages treated with MAPK inhibitors and infected with Ye wt. Finally, rGal1 administration did not reverse the protective effect in Peyer Patches (PPs) of mice infected with Ye ∆. Our study reveals a cooperative role of YopP and endogenous Gal1 during Ye infection.
（叶）将外蛋白（Yops）插入细胞质以感染宿主细胞。然而，尽管取得了相当大的进展，但该过程中涉及的机制，包括 Yops 与宿主蛋白的关联，仍不清楚。在这里，我们评估了半乳糖凝集素-1（Gal1）的功能作用，半乳糖凝集素-1 是一种内源性β-半乳糖苷结合蛋白，可调节 Yop 与宿主细胞的相互作用。我们的结果表明，Gal1 以碳水化合物依赖的方式与 Yops 结合。有趣的是，Gal1 与 Yops 的结合保护这些毒力因子免受胰蛋白酶消化。鉴于 Ye 感染的早期控制涉及巨噬细胞的激活，我们评估了 Gal1 和 YopP 在调节巨噬细胞功能中的作用。尽管 Gal1 和 YopP 不影响 Ye 感染的巨噬细胞产生超氧阴离子和/或 TNF，但它们协同抑制一氧化氮（NO）的产生。值得注意的是，重组 Gal1（rGal1）不能挽救 YopP 突变体 Ye∆感染的巨噬细胞中观察到的 NO 增加。虽然 NO 诱导巨噬细胞凋亡，但在 Ye∆感染的 Gal1 缺陷型巨噬细胞和 Ye wt 感染的 WT 巨噬细胞之间未检测到细胞死亡的显著差异。引人注目的是，用 MAPK 抑制剂处理的 WT 巨噬细胞中观察到的 NO 产生增加，并感染了 Ye wt。最后，rGal1 的给药并没有逆转在 Ye∆感染的 小鼠的派尔斑（PPs）中观察到的保护作用。我们的研究揭示了 YopP 和内源性 Gal1 在 Ye 感染过程中的协同作用。
