BACTERIAL EPITHELIAL CROSSTALK IN DEVELOPING INTESTINE

这个实验室二十年来一直研究肠道宿主防御的发展。 定植和入侵微生物、它们的毒素和外来抗原。我们已经证明了 在许多情况下，未成熟的人类肠道细胞不能抵御病原体，或者对微生物/微生物毒素--肠道细胞“串扰”做出不适当的反应。在过去的研究期间，我们已经证明了外毒素(霍乱毒素)和内毒素(脂多糖)的反应都是过度的，由于未成熟的肠细胞表达IkappaB的不足，未成熟的人的肠细胞无法区分共生和病理的定植细菌。基于这些先前的观察，我们假设未成熟的(不适当的)肠道细胞对定植细菌的反应可能是与年龄相关的胃肠道感染/炎症性疾病的原因。为了验证这一假说，我们将研究发育中的肠道中细菌-上皮“串扰”的分子特征，即上皮对细菌的反应及其保守的病原体相关分子模式(PAMPs)。因此，我们的具体目标是通过使用未成熟的肠上皮细胞与成熟的肠上皮细胞。A1.目的：探讨IkappaB在肠道发育调控表达的机制。A2.目的：探讨干扰素-γ在发育中肠道免疫成熟及调节肠道炎症中的作用。A3.探讨TOII样受体(TLR)家族(尤其是TLR2、4、5)在肠道定植和炎症刺激后的表达及对PAMPs反应的发育差异，以探讨TLR家族在这一过程中的作用。这些研究的结果应该可以更好地了解定植细菌如何与发育中的肠道相互作用，并可能建立激活正常微生物上皮“串扰”和预防与年龄相关的新生儿胃肠道疾病的策略。

This laboratory has for two decades studied the development of intestinal host defense against colonizing and invading microorganisms, their toxins and foreign antigens. We have shown that the immature human enterocyte in many instances fails to protect against pathogens or responds inappropriately to microbial/microbial toxin-enterocyte "crosstalk". During the last research period, we have shown that both the exotoxin (cholera toxin) and endotoxin (lipopolysaccharide) responses are excessive and immature human enterocytes fail to distinguish between commensal and pathologic colonizing bacteria due to an underexpression of IkappaB by immature enterocytes. Based on these previous observations, we hypothesize that an immature (inappropriate) enterocyte response to colonizing bacteria may account for age-related gastrointestinal infectious/inflammatory diseases. To test this hypothesis, we will study bacterial-epithelial "crosstalk" in the developing intestine with regard to the molecular characterization of the epithelial response to bacteria and their conserved pathogen-associated molecule pattern (PAMPs). Accordingly, our specific aims are by using immature vs. mature intestinal epithelial cells. A1. To determine the mechanistic basis for the developmentally-regulated expression of IkappaB in the intestine. A2. To evaluate the role of IFN-gamma in immunologic maturation of the developing intestine and in regulating intestinal inflammation. A3. To study of the role of the TOII-like receptor (TLR) family (particularly TLR2, 4, 5) in this process by determining developmental differences between fetal and mature enterocytes in TLR expression and response to PAMPs after colonization and inflammatory stimulation. The results of these studies should provide a better understanding of how colonizing bacteria interact with the developing gut and may establish strategies for activating normal microbial epithelial "crosstalk" and preventing age-related neonatal gastrointestinal disease.