Dept. of Pediatrics, Univ. of Arizona, Tucson, 85724-5073, USA.
Am J Physiol Gastrointest Liver Physiol. 2010 Sep;299(3):G614-22. doi: 10.1152/ajpgi.00076.2010. Epub 2010 Jun 10.
Necrotizing enterocolitis (NEC) is a devastating intestinal disease of premature infants. Epidermal growth factor (EGF) is one of the most promising candidates in NEC prophylaxis. Autophagy regulates cell homeostasis, but uncontrolled activation of autophagy may lead to cellular injury. The aim was to evaluate the effects of EGF on intestinal autophagy in epithelial cells and in the rat NEC model and measure autophagy in NEC patients. Intestinal epithelial cells (IEC-6) and the rat NEC model were used to study the effect of EGF on intestinal autophagy. Protein levels of Beclin 1 and LC3II were measured in the intestinal epithelium in both in vivo and in vitro models. Ultrastructural changes in intestinal epithelium were studied by electron microscopy. Expression of Beclin 1, LC3II, and p62 protein was evaluated in biopsies from NEC patients. Autophagy was induced in IEC-6 cells and inhibited by adding EGF into the culture. In the rat NEC model, EGF treatment of NEC reduced expression of Beclin 1 and LC3II in ileal epithelium. Morphologically, typical signs of autophagy were observed in the epithelium of the NEC group, but not in the EGF group. A strong signal for Beclin 1 and LC3II was detected in the intestine from patients with NEC. Autophagy is activated in the intestinal epithelium of NEC patients and in the ileum of NEC rats. Supplementation of EGF blocks intestinal autophagy in both in vivo and in vitro conditions. Results from this study indicate that EGF-mediated protection against NEC injury is associated with regulation of intestinal autophagy.
坏死性小肠结肠炎（NEC）是早产儿的一种严重肠道疾病。表皮生长因子（EGF）是预防 NEC 最有希望的候选药物之一。自噬可调节细胞内稳态，但自噬的失控激活可能导致细胞损伤。本研究旨在评估 EGF 对肠上皮细胞和大鼠 NEC 模型中肠自噬的影响，并测量 NEC 患者的自噬情况。使用肠上皮细胞（IEC-6）和大鼠 NEC 模型来研究 EGF 对肠自噬的影响。在体内和体外模型中测量肠上皮细胞中 Beclin 1 和 LC3II 的蛋白水平。通过电子显微镜研究肠上皮细胞的超微结构变化。评估 NEC 患者活检组织中 Beclin 1、LC3II 和 p62 蛋白的表达。在 IEC-6 细胞中诱导自噬，并通过向培养物中添加 EGF 来抑制自噬。在大鼠 NEC 模型中，EGF 处理可降低回肠上皮中 Beclin 1 和 LC3II 的表达。形态学上，在 NEC 组的上皮中观察到典型的自噬迹象，但在 EGF 组中没有。在 NEC 患者的肠道中检测到强烈的 Beclin 1 和 LC3II 信号。NEC 患者的肠上皮和 NEC 大鼠的回肠中均激活了自噬。EGF 的补充在体内和体外条件下均可阻断肠自噬。本研究结果表明，EGF 介导的对 NEC 损伤的保护作用与调节肠自噬有关。
