Sarabia-Sainz Héctor Manuel, Mata Haro Verónica, Sarabia Sainz José Andre-I, Vázquez-Moreno Luz, Montfort Gabriela Ramos-Clamont
Laboratorio de Bioquímica de Proteínas y Glicanos Coordinación de Ciencia de los Alimentos, Centro de Investigación en Alimentación y Desarrollo A.C., Hermosillo, Sonora 83304, México.
Departamento de Investigación en Física, Universidad de Sonora, Hermosillo Sonora 83000, México.
Acta Biochim Pol. 2017;64(4):679-686. doi: 10.18388/abp.2017_2199. Epub 2017 Dec 5.
Adhesion of enterotoxigenic (ETEC) E. coli to host intestinal cells is mediated by lectin-like fimbriae that bind to specific glycan moieties on the surfaces of enterocytes. To prevent in vitro binding of E. coli F4 fimbriae (F4 ETEC) to piglet enterocytes, neoglycans were synthesized by the Maillard reaction conjugating lactose (Lac), galacto-oligosaccharides (GOS) or chitin oligosaccharides (Ochit) to porcine serum albumin (PSA). Neoglycans were characterized by SDS-PAGE, intrinsic tryptophan fluorescence and recognition by plant lectins, as well as by F4 ETEC variants. Electrophoretic patterns suggested the binding to PSA of 63, 13 and 2 molecules of Lac, GOS and Ochit, respectively. All neoglycans displayed quenching of tryptophan fluorescence consistent with the degree of glycation estimated by SDS-PAGE. Plant lectins recognized the neoglycans according to their specificity, whereas antigenic variants of F4 ETEC (ab, ac and ad) recognized PSA-Ochit and PSA-Lac with higher affinity than that for GOS. Neoglycans partially hindered the in vitro binding of F4 ETEC to piglet enterocytes in a dose-dependent manner. The most effective blocking was observed with PSA-Lac that partially inhibited the adhesion of bacteria to enterocytes in a dose dependent manner, as quantified by flow cytometry. Increased production of the cytokines IL-6 and TNF-α was observed in response to F4 ETEC infection of enterocytes and production was reduced in the presence of PSA-Ochit and PSA-GOS. These results suggest that neoglycans synthesized by the Maillard reaction could be useful in the prophylaxis of diarrhea in piglets.
产肠毒素大肠杆菌(ETEC)与宿主肠道细胞的黏附是由凝集素样菌毛介导的,这些菌毛可与肠上皮细胞表面的特定聚糖部分结合。为了防止大肠杆菌F4菌毛(F4 ETEC)在体外与仔猪肠上皮细胞结合,通过美拉德反应将乳糖(Lac)、低聚半乳糖(GOS)或几丁质寡糖(Ochit)与猪血清白蛋白(PSA)结合,合成了新糖。通过SDS-PAGE、内源性色氨酸荧光、植物凝集素识别以及F4 ETEC变体对新糖进行了表征。电泳图谱表明,Lac、GOS和Ochit分别有63、13和2个分子与PSA结合。所有新糖均表现出色氨酸荧光猝灭,这与SDS-PAGE估计的糖基化程度一致。植物凝集素根据其特异性识别新糖,而F4 ETEC的抗原变体(ab、ac和ad)对PSA-Ochit和PSA-Lac的识别亲和力高于对GOS的识别亲和力。新糖以剂量依赖性方式部分阻碍了F4 ETEC在体外与仔猪肠上皮细胞的结合。通过流式细胞术定量分析发现,PSA-Lac的阻断效果最为显著,它以剂量依赖性方式部分抑制了细菌与肠上皮细胞的黏附。在F4 ETEC感染肠上皮细胞后,观察到细胞因子IL-6和TNF-α的产生增加,而在存在PSA-Ochit和PSA-GOS的情况下,其产生减少。这些结果表明,通过美拉德反应合成的新糖可能有助于预防仔猪腹泻。