Mammalian milk exosomal miRNAs play an important role in maintaining intestinal immune homeostasis and protecting epithelial barrier function, but the specific miRNAs and whether miRNA-mediated mechanisms are responsible for these benefits remain a matter of investigation. This study isolated sheep milk-derived exosomes (sheep MDEs), identifying the enriched miRNAs in sheep MDEs, oar-miR-148a, and oar-let-7b as key components targeting TLR4 and TRAF1, which was validated by a dual-luciferase reporter assay. In dextran sulfate sodium-induced colitis mice, administration of sheep MDEs alleviated colitis symptoms, reduced colonic inflammation, and systemic oxidative stress, as well as significantly increased colonic oar-miR-148a and oar-let-7b while reducing toll-like receptor 4 (TLR4) and TNF-receptor-associated factor 1 (TRAF1) level. Further characterization in TNF-α-challenged Caco-2 cells showed that overexpression of these miRNAs suppressed the TLR4/TRAF1-IκBα-p65 pathway and reduced IL-6 and IL-12 production. These findings indicate that sheep MDEs exert gastrointestinal anti-inflammatory effects through the miRNA-mediated modulation of TLR4 and TRAF1, highlighting their potential in managing colitis.

中文翻译：

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绵羊（绵羊）乳汁外泌体 miRNA 通过抑制 TLR4 和 TRAF-1 减轻葡聚糖硫酸钠诱导的小鼠结肠炎


哺乳动物乳汁外泌体 miRNA 在维持肠道免疫稳态和保护上皮屏障功能方面发挥着重要作用，但具体的 miRNA 以及 miRNA 介导的机制是否负责这些益处仍然是一个研究问题。本研究分离了羊奶来源的外​​泌体（羊 MDE），鉴定了羊 MDE 中富集的 miRNA、oar-miR-148a 和 oar-let-7b 作为靶向 TLR4 和 TRAF1 的关键成分，并通过双荧光素酶报告基因验证化验。在葡聚糖硫酸钠诱导的结肠炎小鼠中，给予绵羊 MDE 可缓解结肠炎症状，减少结肠炎症和全身氧化应激，并显着增加结肠 oar-miR-148a 和 oar-let-7b，同时减少 Toll 样受体 4 (TLR4) 和 TNF 受体相关因子 1 (TRAF1) 水平。 TNF-α 攻击的 Caco-2 细胞中的进一步表征表明，这些 miRNA 的过表达抑制了 TLR4/TRAF1-IκBα-p65 通路并减少了 IL-6 和 IL-12 的产生。这些发现表明，绵羊 MDE 通过 miRNA 介导的 TLR4 和 TRAF1 调节发挥胃肠道抗炎作用，凸显了它们在治疗结肠炎方面的潜力。