Meprin A impairs epithelial barrier function, enhances monocyte migration, and cleaves the tight junction protein occludin
Meprin A impairs epithelial barrier function, enhances monocyte migration, and cleaves the tight junction protein occludin
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DOI：
10.1152/ajprenal.00179.2012
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发表时间：
2013-09-01
影响因子：
4.2
通讯作者：
Bond, Judith S.
中科院分区：
文献类型：
--
作者：
Bao, Jialing;Yura, Renee E.;Bond, Judith S.
Meprin金属蛋白酶在肠和肾的腔界面处以及在某些白细胞中高度表达。Meprins在体外切割多种底物，包括细胞外基质蛋白、粘附连接蛋白和细胞因子，并且已经涉及许多炎性疾病。然而，体外结果与发病机制之间的联系尚未阐明。本研究旨在确定是否meprins是破坏上皮屏障功能的决定性因素。活性meprin A或meprin B应用于Madin-Darby犬肾（MDCK）细胞单层增加了对异硫氰酸荧光素-葡聚糖的渗透性，并破坏了紧密连接蛋白occludin的免疫染色，但没有claudin-4。在MDCK单层中，Meprin A而不是meprin B切割闭合蛋白。用重组occludin进行的实验表明，meprin A在第一胞外环上的Gly（100）和Ser（101）之间切割蛋白质。体内实验表明，注入小鼠膀胱的meprin A增加了上皮细胞对荧光素钠的通透性。此外，来自C57 BL/6背景的meprin敲除小鼠的单核细胞比来自其野生型对应物的单核细胞更不能够通过MDCK单层迁移。这些结果证明了meprin A破坏上皮屏障的能力，并表明occludin是meprin A调节炎症的重要靶点之一。
Meprin metalloproteases are highly expressed at the luminal interface of the intestine and kidney and in certain leukocytes. Meprins cleave a variety of substrates in vitro, including extracellular matrix proteins, adherens junction proteins, and cytokines, and have been implicated in a number of inflammatory diseases. The linkage between results in vitro and pathogenesis, however, has not been elucidated. The present study aimed to determine whether meprins are determinative factors in disrupting the barrier function of the epithelium. Active meprin A or meprin B applied to Madin-Darby canine kidney (MDCK) cell monolayers increased permeability to fluorescein isothiocyanate-dextran and disrupted immunostaining of the tight junction protein occludin but not claudin-4. Meprin A, but not meprin B, cleaved occludin in MDCK monolayers. Experiments with recombinant occludin demonstrated that meprin A cleaves the protein between Gly(100) and Ser(101) on the first extracellular loop. In vivo experiments demonstrated that meprin A infused into the mouse bladder increased the epithelium permeability to sodium fluorescein. Furthermore, monocytes from meprin knockout mice on a C57BL/6 background were less able to migrate through an MDCK monolayer than monocytes from their wild-type counterparts. These results demonstrate the capability of meprin A to disrupt epithelial barriers and implicate occludin as one of the important targets of meprin A that may modulate inflammation.