一种乳源内源性多肽PDC190用于新生儿坏死性小肠结肠炎防治的应用基础研究

PDC190 is a novel endogenous peptide derived from beta-casein without any function report, which was identified by mass spectrometry in human colostrum. Our previous study indicates that PDC190 antagonized the effects of LPS, and thus restored enterocyte cell proliferation capacity, inhibited apoptosis and inflammation cytokine production. And PDC190 maintained the integrity of the intestinal mucosa in the necrotizing enterocolitis (NEC) rat model. Further study reveals that it exerts its function through suppressing aberrant activation of NF-κB signaling which is closely associated with cell proliferation, apoptosis and inflammation. So we hypothesize that PDC190 protects the intestinal mucosa during the pathogenesis of NEC by regulating NF-κB signaling pathway. To systematically evaluate the feasibility and possibility of PDC190 for prevention and treatment of neonatal NEC, we will detect the content of PDC190 in different human milk, evaluate its stability and side effect and explore the protection effects of PDC190 on epithelial damage repair and experimental NEC. Furthermore, we will further illustrate the molecular mechanism of PDC190 in protecting against NEC through inhibiting of NF-κB signaling pathway by pull down assay and so on. These studies may provide a new strategy for the treatment of NEC.

PDC190是我们从母乳中借助质谱技术新发现的、β-酪蛋白来源、功能未知的内源性多肽。前期发现，PDC190可恢复LPS抑制的肠上皮细胞增殖、抑制LPS诱导的细胞凋亡和炎症因子分泌，动物实验则证实PDC190具有保护NEC肠道粘膜完整性的作用，其作用与机制可能与抑制NF-κB信号通路的异常活化有关。已知NF-κB信号通路与细胞增殖、凋亡以及炎症因子密切相关，因此我们提出PDC190通过调控NF-κB信号通路保护NEC肠道粘膜的假说。研究拟通过检测不同母乳中PDC190含量的变化、评估PDC190的稳定性和毒副作用，论证PDC190防治NEC的可行性；通过细胞与动物实验，系统论证PDC190对肠上皮细胞功能的损伤修复作用及治疗NEC的可能性；通过Pull-down等实验，深入阐明PDC190通过抑制NF-κB信号通路保护NEC的分子机制。研究可望为新生儿NEC防治提供新手段。

坏死性小肠结肠炎是新生儿特别是早产儿死亡的重要原因。目前NEC的临床治疗主要采用禁食、静脉注射抗生素为主的内科干预和以剖腹探查和肠切除为主的外科干预方法为主；但内科干预并不能完全防止NEC 的恶化，而手术愈后往往伴有严重的后遗症如肠狭窄和短肠综合征等。近年来NEC 的发病逐年增加，因此寻找NEC 有效的防治措施极为迫切。临床诊疗指南明确指出母乳喂养可降低 NEC 的发病率。PDC190是我们从母乳中借助质谱技术新发现的、β-酪蛋白来源、功能未知的内源性多肽。我们的研究发现，①早产儿初乳中PDC190多肽含量显著高于足月儿产妇初乳，且毒副作用小；② PDC190可恢复LPS抑制的肠上皮细胞（FHC和IEC-6细胞）迁移和增殖，抑制LPS诱导的炎症因子分泌；③NEC小鼠模型实验则证实PDC190可以恢复小肠上皮细胞的增殖，抑制炎症因子的产生，减少炎症细胞的浸润，具有保护NEC肠道粘膜完整性的作用；④ 揭示了PDC190通过抑制PI3K-Akt信号通路发挥保护NEC的作用，PI3K的激动剂ys49可显著增高PDC190抑制的p-Akt和p-PI3K的减少，进一步阐明了PDC190保护NEC的作用和分子机制。母乳内源性多肽多肽毒副作用小、经济成本低，且在抗菌、免疫调节等方面均有作用，因此，PDC190有望成为防治NEC的最佳治疗手段，具有潜在的经济价值和较大的社会价值。