Hyperosmolarity-induced cornification of human corneal epithelial cells is regulated by JNK MAPK
Hyperosmolarity-induced cornification of human corneal epithelial cells is regulated by JNK MAPK
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DOI：
10.1167/iovs.07-0569
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发表时间：
2008-02-01
影响因子：
4.4
通讯作者：
Pflugfelder, Stephen C.
中科院分区：
文献类型：
--
作者：
Chen, Zhuo;Tong, Louis;Pflugfelder, Stephen C.
目的.目的探讨高渗应激对原代培养的人角膜上皮细胞（PCHCE）表达角膜囊膜前体蛋白（CE）和转氨酶（TG）的影响，以及JNK MAPK在这一过程中的调节作用。在暴露于增加渗透压（350-450 mOsM）的培养基24、48和72小时的PCHCE细胞中评价CE前体和TG的表达。JNK 1和-2 MAPK的抑制通过添加短干扰（si）RNA。评估mRNA转录物和蛋白质的相对水平。在PCHCE细胞中检测TG活性、细胞存活率和凋亡，有或没有siRNA-JNKs. siRNA。PCHCE细胞暴露于高渗介质中3小时增加TG活性，6小时增加CE前体SPRR 1b和-2a和膜相关TG 1 mRNA水平，24小时增加组织型TG 2 mRNA水平。渗透压降低角膜上皮细胞的活力，这部分是由于刺激细胞凋亡和角化死亡。siRNA抑制PCHCE细胞JNK 2的产生可抑制SPRR的刺激和膜相关TG 1的产生及TG活性，提高细胞活力，而抑制JNK 1则可预防早期凋亡。渗透压促进某些CE蛋白和交联膜相关TG 1的产生，并通过JNK MAPK介导的途径降低细胞活力。抑制JNK产生的策略下调PCHCE细胞对渗透胁迫的角化反应。这些发现对于预防干眼病中高渗性泪膜引起的角膜上皮角化具有潜在的治疗意义。
PURPOSE. To evaluate the effects of hyperosmolar stress on expression of cornified envelope (CE) precursors and transglutaminases (TGs) by primary cultured human corneal epithelial (PCHCE) cells and the regulatory effects of JNK MAPK on this process.METHODS. Expression of CE precursors and TGs were evaluated in PCHCE cells exposed to media of increasing osmolarity (350-450 mOsM) for 24, 48, and 72 hours. JNK1 and -2 MAPKs were inhibited by addition of short interfering (si) RNA. Relative levels of mRNA transcripts and proteins were evaluated. TG activity, cell viability, and apoptosis were detected in PCHCE cells, with or without siRNA-JNKs.RESULTS. Exposure of PCHCE cells to hyperosmolar medium increased TG activity at 3 hours, levels of the CE precursors SPRR1b and -2a and membrane-associated TG1 mRNA at 6 hours, and tissue-type TG2 mRNA at 24 hours. Osmotic stress decreased corneal epithelial cell viability, which was due in part to stimulation of apoptosis and cornification death. Inhibiting JNK2 production by siRNA in osmotically stressed PCHCE cells prevented the stimulation of SPRR and membrane-associated TG1 production and TG activity, and improved cell viability, whereas inhibition of JNK1 prevented early apoptosis.CONCLUSIONS. Osmotic stress promotes production of certain CE proteins and cross-linking membrane-associated TG1 and decreases cell viability via JNK MAPK-mediated pathways. Strategies that inhibit JNK production downregulate the cornification response of PCHCE cells to osmotic stress. These findings have potential therapeutic implications for preventing cornification of the corneal epithelium in response to the hyperosmolar tear film in dry eye disease.