Lionetti P, Pazzaglia A, Moriondo M, Azzari C, Resti M, Amorosi A, Vierucci A
Department of Pediatrics, University of Florence, Italy.
J Pediatr Gastroenterol Nutr. 1999 Sep;29(3):308-13. doi: 10.1097/00005176-199909000-00013.
Growth-inhibitory autocrine polypeptides such as transforming growth factor (TGF)-beta may play a role in the control of normal epithelial cell proliferation and differentiation. In addition, TGF-beta has a central role in extracellular matrix homeostasis and regulates the immune response at the local level. In this study immunohistochemistry was used to examine the pattern of TGF-beta protein distribution and quantitative reverse transcription-polymerase chain reaction (RT-PCR) to determine levels of TGF-beta messenger RNA expression in normal intestinal mucosa and in the flat mucosa of children with celiac disease.
Small intestinal biopsies were performed in children with active celiac disease and in histologically normal control subjects. Frozen sections were single stained using an anti-TGF-beta monoclonal antibody and were double stained for TGF-beta and T cell, macrophages, and the activation marker CD25. Total RNA was extracted from frozen specimens and competitive quantitative RT-PCR performed for TGF-beta mRNA using internal synthetic standard RNA.
In normal intestinal mucosa, by immunohistochemistry, TGF-beta expression was most prominent in the villous tip epithelium, whereas in the lamina propria, weak immunoreactivity was present. The celiac mucosa showed weak and patchy epithelial TGF-beta immunoreactivity. In contrast, an intense staining positivity was present in the lamina propria localized mostly in the subepithelial region where T cells, macrophages, and CD25+ cells were detected by double staining. By quantitative RT-PCR, levels of TGF-beta mRNA transcripts appeared to be increased in celiac intestinal mucosa compared with that in control subjects, although the difference did not reach statistical significance.
These observations suggest that TGF-beta expression is associated with differentiated enterocyte function. In celiac disease the lower TGF-beta epithelial cell expression could be a consequence of the preponderance of a less differentiated epithelial cell phenotype also present in the surface epithelium. In contrast, the prominent TGF-beta positivity of the subepithelial lamina propria suggests an association with the local immune and inflammatory response, as well as a potential role of these peptides in mesenchymal-epithelial cell interaction.
生长抑制性自分泌多肽，如转化生长因子（TGF）-β，可能在正常上皮细胞增殖和分化的控制中发挥作用。此外，TGF-β在细胞外基质稳态中起核心作用，并在局部水平调节免疫反应。在本研究中，采用免疫组织化学检测TGF-β蛋白的分布模式，并通过定量逆转录-聚合酶链反应（RT-PCR）来确定正常肠黏膜和乳糜泻患儿扁平黏膜中TGF-β信使核糖核酸的表达水平。
对患有活动性乳糜泻的儿童和组织学正常的对照受试者进行小肠活检。冰冻切片用抗TGF-β单克隆抗体进行单染色，并对TGF-β与T细胞、巨噬细胞及活化标志物CD25进行双重染色。从冰冻标本中提取总RNA，并使用内部合成标准RNA对TGF-β信使核糖核酸进行竞争性定量RT-PCR。
在正常肠黏膜中，通过免疫组织化学检测，TGF-β表达在绒毛顶端上皮最为显著，而在固有层中，免疫反应较弱。乳糜泻黏膜显示上皮TGF-β免疫反应较弱且呈斑片状。相比之下，固有层中存在强烈的染色阳性，主要位于上皮下区域，通过双重染色可检测到T细胞、巨噬细胞和CD25+细胞。通过定量RT-PCR，与对照受试者相比，乳糜泻肠黏膜中TGF-β信使核糖核酸转录本水平似乎有所增加，尽管差异未达到统计学意义。
这些观察结果表明，TGF-β表达与分化的肠上皮细胞功能相关。在乳糜泻中，上皮细胞TGF-β表达较低可能是表面上皮中分化程度较低的上皮细胞表型占优势的结果。相比之下，上皮下固有层中显著的TGF-β阳性表明其与局部免疫和炎症反应相关，以及这些肽在间充质-上皮细胞相互作用中的潜在作用。
