Studies of regulatory signaling molecule SMAD in pediatric allergic and chronic inflammatory diseases

辅助性T细胞主要根据其细胞因子的产生情况分为三大类：Th1、Th2和Th3细胞。Thi1细胞产生IL-2、干扰素-γ和肿瘤坏死因子-α，主要参与细胞介导的免疫反应。Th2细胞产生IL-4、IL-5、IL-9、IL-10和IL-13，促进嗜酸性粒细胞增多，并通常增强抗体反应，包括IgE介导的过敏症患者。最后，Th3细胞通过产生转化生长因子β来调节Th1和Th2细胞因子的产生。转化生长因子-β具有广泛的调节活性，包括诱导口服耐受性、强大的抗炎作用、粘膜免疫球蛋白A的表达以及对上皮细胞的增殖和分化的影响。转化生长因子-β通过受体丝氨酸激酶发出信号，然后丝氨酸激酶磷酸化，从而激活转录因子Smad2和Smad3。Smad4是一种常见的介质，然后与这些激活的分子结合，并向细胞核发送信号。Smad7分子也可能作为拮抗剂Smad7发挥作用，并可能抑制…更多t转化生长因子-β介导的Smad3磷酸化减弱转化生长因子-β信号进入细胞核。在这个项目中，我们组织了一系列研究，以检验转化生长因子-β在慢性炎症性疾病中的作用。我们还研究了转化生长因子-β信号在婴儿早期的免疫学发展。我们第一次调查了一名患有特应性皮炎、肾病综合征、胰岛素依赖型糖尿病和原田氏病的女孩。由于Th1和Th2介导的慢性炎症性疾病在单个患者中存在，因此对转化生长因子-β/Smad调节信号进行了研究。为评价早产儿的免疫发育状况，我们检测了早产儿在出生后第0、14、28天血清细胞因子水平及Th2型和Th1型趋化因子受体CCR4和CCR5的表达。血清IL-4水平在第14天有所升高，但在第28天降至初始水平。血清转化生长因子-β_1水平在第14天显著升高，但在第28天降至初始水平。逆转录-聚合酶链式反应证实CCR5-mRNA在出生后不久即有表达，而CCR4-mRNA未见表达。此后，CCR4-mRNA的表达显著增加，至第28天达到CCR5-mRNA的表达水平。因此，从第0天到第28天，CCR4+CD4^+细胞显著增加，而FACS未检测到CCR5+CD4^+细胞。IL-4和转化生长因子-β_1的合成增加以及CCR4^+CD4^+细胞的增加表明，在母体外的情况下，即使早产儿在分娩后不久也有倾向于Th2型反应的倾向，而他们可能在出生后不久就能够产生Th1介导的反应。然后，我们研究了益生菌短双歧杆菌对早产儿免疫系统的影响。B.breve组血清转化生长因子-β_1水平在第14天开始升高，第28天仍维持在较高水平。与第28天的对照组相比，B.breve给药后Smad3的mRNA表达水平升高，Smad7(拮抗剂Smad)的mRNA表达水平降低。这些结果表明，给早产儿使用B.breve可以上调转化生长因子-β-1信号，可能有助于减轻早产儿的炎症和过敏反应。较少

Helper T cells are classified mainly into three broad types according to their cytokine production profile : Th1,Th2, and Th3 cells. Thi1 cells produce IL-2,IFN-γ and TNF-α and mainly involve cell-mediated immunological reactions. Th2 cells produce IL-4,IL-5,IL-9,IL-10, and IL-13, which promote eosinophilia and generally boost antibody responses including IgE-mediated allergic patients. Lastly, Th3 cells regulate Th1 and Th2 cytokine production by producing TGF-β. TGF-β has a broad spectrum of activities in regulation, including induction of oral tolerance, potent anti-inflammatory effects, mucosal IgA expression, and effects on epithelial cell proliferation and differentiation. TGF-β signals through a receptor serine kinase that then phosphorylates and thereby activates transcription factors Smad2 and Smad3. Smad4, a common mediator, then binds to these activated molecules and can send signals to the nucleus. The Smad7 molecule may also function as an antagonistic Smad, and may inhibi … More t TGF-β-mediated Smad3 phosphorylation to attenuate TGF-β signaling to the nucleus. In this project, we organized a series of studies to examine the effects of TGF-β in chronic inflammatory diseases. We have also investigated the immunological development if TGF-β signaling in early infancy.We have first investigated a girl with atopic dermatitis, nephrotic syndrome, insulin dependent diabetes mellitus, and Harada's disease. Since Th1- and Th2-mediated chronic inflammatory diseases are present in a single patient, a TGF-β/Smad regulatory signal was investigated. Enhanced expression of Smad7, an antagonist for TGF-β signaling, was confirmed, suggested that lack of regulatory signaling might contribute chronic inflammatory diseases including her disease status.To evaluate the immunological development of preterm infants, we examined the serum cytokine levels and the expression of Th2 and Th1 chemokine receptors, CCR4 and CCR5, on day 0, 14, and 28 in preterm infants. Serum IL-4 levels exhibited an increase on day 14, but decreased to the initial level on day 28. The significant elevation of serum TGF-β_1 levels was confirmed on day 14 but decreased to the initial level on day 28. The RT-PCR confirmed the expression of CCR5-mRNA soon after birth, while there was no expression of CCR4-mRNA. Thereafter, the expression of CCR4-mRNA increased significantly and reached the level of CCR5-mRNA expression on day 28. Thus, CCR4^+CD4^+ cells were significantly increased from day 0 to 28, while CCR5^+CD4^+ cells were not analyzed by FACS. Increased IL-4 and TGF-β_1 synthesis as well as increased CCR4^+CD4^+ cells suggest that, under extra-maternal circumstances, there is a shift in bias toward Th2 responses even in preterm infants soon after delivery, while they may be capable of developing Th1 mediated responses soon after birth.We, then, examined the effect of probiotics, Bifidobacterium breve, on the immunological system of preterm infants. Serum TGF-β_1 level was elevated on day 14 and remained elevated on day 28 in the B.breve group. Level of mRNA expression was enhanced for Smad3 and reduced for Smad7 (antagonistic Smad) after B.breve administration relative to levels in Controls on day 28. These results demonstrated that the administration of B.breve to preterm infants can up-regulate TGF-β1 signaling and may possibly be beneficial in attenuating inflammatory and allergic reactions in these infants. Less