Nubile Mario, Lanzini Manuela, Calienno Roberta, Mastropasqua Rodolfo, Curcio Claudia, Mastropasqua Alessandra, Agnifili Luca, Mastropasqua Leonardo
Department of Medicine and Science of Ageing, Ophthalmology Clinic, University G. D'Annunzio Chieti-Pescara, Italy.
Mol Vis. 2013;19:146-52. Epub 2013 Jan 28.
To study the expression of S100 A and B family proteins in normal human limbus and to analyze modification of the expression in inflammatory conditions.
The total expression of members of the S100 family and the expression of A4, A8, A9, and B individually were evaluated in nine normal human corneal limbi, collected from cadaver healthy donors, in particular in the limbal epithelial crypts (LECs), and in five inflamed limbi obtained from enucleated eyes. S100 protein distribution was determined with immunohistochemistry staining analysis.
Cytoplasmic expression of total S100 proteins was observed in 100% of LECs; in contrast, the inflamed tissues were completely negative, and faint positivity was observed in only one case. Moreover, cytoplasmic expression of S100 A4 and A9 was uniformly found in the entire LECs in all samples analyzed, while S100 A8 positivity was observed in only 44.4% of cases and only in the cells localized in the central area of the LEC. Positivity for S100 B was not observed in all samples analyzed.
As reported in the literature, normal limbal epithelial cells show strong expression of S100 proteins. A novel finding of this study was the expression for the limbal epithelial crypts. In particular, S100 A4 and A9, which are normally involved in regulating a wide range of biologic effects, including cell motility, survival, and differentiation, are the most expressed members in healthy limbal crypts. In inflamed tissues, expression of S100 proteins was dramatically decreased. S100 proteins, and in particular S100 A4 and S100 A9, can be useful as markers of early changes in stem cell niches due to inflammation.
研究S100 A和B家族蛋白在正常人角膜缘的表达，并分析炎症状态下表达的变化。
对从尸体健康供体获取的9个正常人角膜缘组织，特别是角膜缘上皮隐窝（LECs），以及5个从摘除眼球获取的炎症角膜缘组织，评估S100家族成员的总表达以及A4、A8、A9和B的单独表达。通过免疫组织化学染色分析确定S100蛋白分布。
在100%的LECs中观察到S100蛋白的细胞质表达；相比之下，炎症组织完全阴性，仅1例观察到微弱阳性。此外，在所分析的所有样本的整个LECs中均一致发现S100 A4和A9的细胞质表达，而仅在44.4%的病例中观察到S100 A8阳性，且仅在位于LEC中心区域的细胞中观察到。在所分析的所有样本中均未观察到S100 B阳性。
如文献报道，正常角膜缘上皮细胞显示S100蛋白的强表达。本研究的一个新发现是角膜缘上皮隐窝的表达。特别是，通常参与调节广泛生物学效应（包括细胞运动、存活和分化）的S100 A4和A9是健康角膜缘隐窝中表达最多的成员。在炎症组织中，S100蛋白的表达显著降低。S100蛋白，特别是S100 A4和S100 A9，可作为炎症导致干细胞微环境早期变化的标志物。
