School of Food Science and Engineering, Shaanxi University of Science and Technology, Xi'an 710000, China.
Tangdu Hospital, Air Force Military Medical University, Xi'an 710000, China.
J Agric Food Chem. 2024 Sep 25;72(38):21030-21040. doi: 10.1021/acs.jafc.4c05524. Epub 2024 Sep 16.
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.
哺乳动物乳源性外泌体 miRNAs 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，但特定的 miRNAs 以及 miRNA 介导的机制是否负责这些益处仍有待研究。本研究分离了绵羊乳源性外泌体（sheep MDEs），鉴定了绵羊 MDEs 中富含的 miRNAs，oar-miR-148a 和 oar-let-7b 作为靶向 TLR4 和 TRAF1 的关键成分，这通过双荧光素酶报告基因检测得到了验证。在葡聚糖硫酸钠诱导的结肠炎小鼠中，给予绵羊 MDEs 可缓解结肠炎症状，减轻结肠炎症和全身氧化应激，同时显著增加结肠 oar-miR-148a 和 oar-let-7b，同时降低 TLR4 和 TNF 受体相关因子 1（TRAF1）水平。在 TNF-α 刺激的 Caco-2 细胞中的进一步表征表明，这些 miRNAs 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 MDEs 通过 miRNA 介导的 TLR4 和 TRAF1 调节发挥胃肠道抗炎作用，突出了它们在管理结肠炎方面的潜力。
