Expression and regulation of cornified envelope proteins in human corneal epithelium
Expression and regulation of cornified envelope proteins in human corneal epithelium
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DOI：
10.1167/iovs.05-1129
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发表时间：
2006-05-01
影响因子：
4.4
通讯作者：
Pflugfelder, Stephen C.
中科院分区：
文献类型：
--
作者：
Tong, Louis;Corrales, Rosa M.;Pflugfelder, Stephen C.
目的。复层鳞状上皮细胞在其外围组装特殊的保护屏障结构，称为角化包膜。本研究的目的是评估人角膜上皮中角质化包膜前体的存在和分布、其在人角膜上皮细胞培养物中的表达，以及紫外线辐射（UVB）和转谷氨酰胺酶（TG）抑制对其表达的影响。方法。通过免疫荧光染色研究了富含脯氨酸的小蛋白（SPRR）以及聚丝蛋白和外皮蛋白在人角膜切片中的组织分布。来自角膜缘外植体的原代人角膜上皮细胞（HCEC）用于细胞培养实验。在存在或不存在单丹酰尸胺 (MDC)（一种 TG 抑制剂）的情况下，使用单剂量 20 mJ/cm(2) 的 UVB 刺激这些细胞。通过免疫荧光染色和蛋白质印迹分析研究 SPRR2 和外皮蛋白水平。通过半定量逆转录聚合酶链式反应研究了12种蛋白质的基因表达。结果。在人角膜组织中，在角膜中央和周边以及角膜缘上皮中检测到SPRR1、SPRR2、聚丝蛋白和外皮蛋白的表达。在 HCEC 中，在胞质部分中检测到 SPRR2 和外皮蛋白，并且外皮蛋白水平在 UVB 后增加。在 MDC 存在的情况下，SPRR2 和外皮蛋白水平都会累积。 HCEC 表达 9 个基因，包括外皮蛋白、SPRR（1A、1B、2A、2B 和 3 型）、晚期包膜蛋白 (LEP) 1 和 16 以及聚丝蛋白。未检测到 SPRR 4、兜甲蛋白和 LEP 6 转录物。 UVB 下调 SPRR (2A, 2B) 和 LEP 1 转录本。结论。各种包膜前体在人角膜上皮和 HCEC 中表达，急性 UVB 应激会差异性地改变它们在 HCEC 中的表达。包膜前体的表达及其通过 UVB 的快速调节支持这些蛋白质在眼表应激调节中的作用。 TG 功能可能与 UVB 刺激的角膜上皮中可溶性前体的调节有关。
PURPOSE. Stratified squamous epithelial cells assemble a specialized protective barrier structure on their periphery, termed the cornified envelope. The purpose of this study was to evaluate the presence and distribution of cornified envelope precursors in human corneal epithelium, their expression in human corneal epithelial cell cultures, and the effect of ultraviolet radiation (UVB) and transglutaminase (TG) inhibition on their expression.METHODS. Tissue distribution of small proline-rich proteins (SPRRs) and filaggrin and involucrin was studied in human cornea sections by immunofluorescence staining. Primary human corneal epithelial cells (HCECs) from limbal explants were used in cell culture experiments. A single dose of UVB at 20 mJ/cm(2) was used to stimulate these cells, in the presence or absence of mono-dansyl cadaverine (MDC), a TG inhibitor. SPRR2 and involucrin protein levels were studied by immunofluorescence staining and Western blot analysis. Gene expression of 12 proteins was investigated by semiquantitative reverse transcription-polymerase chain reaction.RESULTS. In human cornea tissue, SPRR1, SPRR2, filaggrin, and involucrin protein expression were detected in the central and peripheral corneal and limbal epithelium. In HCECs, SPRR2 and involucrin proteins were detected in the cytosolic fraction, and involucrin levels increased after UVB. Both SPRR2 and involucrin levels accumulated in the presence of MDC. Nine genes including involucrin, SPRR (types 1A, 1B, 2A, 2B, and 3), late envelope protein (LEP) 1 and 16, and filaggrin were expressed by HCECs. SPRR 4, loricrin, and LEP 6 transcripts were not detected. UVB downregulated SPRR (2A, 2B) and LEP 1 transcripts.CONCLUSIONS. Various envelope precursors are expressed in human corneal epithelium and in HCECs, acute UVB stress differentially alters their expression in HCECs. The expression of envelope precursors and their rapid modulation by UVB supports the role of these proteins in the regulation of ocular surface stress. TG function may be relevant in the regulation of soluble precursors in UVB-stimulated corneal epithelium.