Exosomes and HB-EGF in Stem Cell-Mediated Therapy for Necrotizing Enterocolitis

描述(申请人提供)：尽管经过几十年的研究，坏死性小肠结肠炎(NEC)的发病率和死亡率仍然没有变化，这是因为我们对如何保护肠道免受这种疾病影响的理解存在根本差距。有证据表明，不成熟的肠道神经系统(ENS)可能使早产儿易患NEC。我们已经证明，在人类和啮齿动物NEC损伤的肠道中存在持久的ENS异常，这种异常在急性疾病明显恢复后很长一段时间内仍然存在。我们的初步数据表明，肝素结合的EGF样生长因子(HB-EGF)和干细胞(SC)移植共同起到保护肠道和ENS免受实验性NEC的作用。我们工作的长期目标是确定新的预防和治疗策略，以保护新生儿免受NEC的影响。目前更新申请的总体目标是确定HB-EGF与SC相互作用的关键元素，这些元素可用于改善对肠道的损伤保护。我们的中心假设是，HB-EGF保护SC的能力在其肠道细胞保护作用中起主要作用，SC的有益作用是由SC分泌的外切体介导的。Exosome是由多种细胞类型分泌的纳米囊泡，它包含microRNAs、mRNAs和反映其产生细胞的转录和/或翻译活动的蛋白质的复杂混合物。我们将客观地测试我们的 中心假说通过追求以下特定目标：目的1)确定在NEC期间，哪种生物来源的干细胞在保护肠道和ENS方面最有效。目的2)建立干细胞治疗的外切体依赖性及外切体HB-EGF的有益作用。目的3)探讨循环外切体的microRNA含量是否可作为NEC的生物标志物。这项拟议研究的意义在于，它将使我们更好地了解HB-EGF和SC在保护肠道和ENS方面的作用，使我们能够最好地设计潜在的基于HB-EGF和SC的临床疗法来治疗NEC。我们研究的积极影响将是为有患NEC风险的患者开发改进的治疗干预措施，并在了解生长因子-干细胞在肠道中的相互作用方面取得根本性进展。这项拟议的研究具有创新性，因为我们寻求利用新的实验疗法，通过联合使用肠道细胞保护性生长因子和干细胞来保护和再生肠道和ENS，还因为它将进一步研究HB-EGF作为促动剂的新观察。

DESCRIPTION (provided by applicant): Despite decades of research, the morbidity and mortality of necrotizing enterocolitis (NEC) remain unchanged due to a fundamental gap in our understanding of how to protect the intestines from this disease. Evidence suggests that an immature enteric nervous system (ENS) may predispose prematures to NEC. We have demonstrated protracted ENS abnormalities in human and rodent NEC-injured intestine that persist long after apparent recovery from the acute disease. Our preliminary data demonstrate that heparin-binding EGF-like growth factor (HB-EGF) and stem cell (SC) transplantation act collectively to protect the intestines and the ENS from experimental NEC. The long-term goal of our work is to identify novel prophylactic and therapeutic strategies to protect neonates from NEC. The overall objective of the current renewal application is to identify key elements of the interaction of HB-EGF with SC that may be utilized to improve protection of the intestines from injury. Our central hypothesis is that the ability of HB-EGF to protect SC plays a major role in it intestinal cytoprotective effects, and that the beneficial effects of SC are mediated by SC-secreted exosomes. Exosomes are nanovesicles that are secreted by many cell types and which contain a complex mixture of microRNAs, mRNAs and proteins that reflect the transcriptional and/or translational activity of their producer cells. We will objectively test our central hypothesis by pursuing the following specific aims: Aim 1) to determine which biological source of stem cells is most effective in protecting the intestine and the ENS from injury during NEC. Aim 2) to establish the exosome dependency of stem cell therapy and the beneficial effects of exosomal HB-EGF. Aim 3) to determine whether the microRNA content of circulating exosomes can be used as biomarkers of NEC. The significance of the proposed research is that it will lead to a better understanding of the effects of HB- EGF and SC on protection of the intestines and the ENS, allowing us to best design potential clinical HB-EGF- and SC-based therapies to treat NEC. The positive impact of our studies will be development of improved therapeutic interventions for patients at risk of developing NEC and fundamental advances in understanding growth factor-stem cell interactions in the intestines. The proposed research is innovative because we seek to utilize novel experimental therapies designed to protect and regenerate the intestine and the ENS through administration of an intestinal cytoprotective growth factor in conjunction with stem cells, and because it will further investigate the novel observation that HB-EGF acts as a pro-motility agent.