ORAI1 Activates Proliferation of Lymphatic Endothelial Cells in Response to Laminar Flow Through Krüppel-Like Factors 2 and 4.
ORAI1 Activates Proliferation of Lymphatic Endothelial Cells in Response to Laminar Flow Through Krüppel-Like Factors 2 and 4.
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DOI：
10.1161/circresaha.116.309548
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发表时间：
2017-04-28
影响因子：
20.1
通讯作者：
Hong YK
中科院分区：
文献类型：
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作者：
Choi D;Park E;Jung E;Seong YJ;Hong M;Lee S;Burford J;Gyarmati G;Peti-Peterdi J;Srikanth S;Gwack Y;Koh CJ;Boriushkin E;Hamik A;Wong AK;Hong YK
淋巴管的功能是从各种组织中排出间质液。虽然已知流体流动产生的剪切应力触发淋巴扩张和重塑，但流动诱导的淋巴生长的分子基础尚不清楚。我们的目的是获得一个更好的了解层流剪应力激活淋巴增殖的机制。将来自真皮血管和淋巴管的原代内皮细胞（BEC和LEC）暴露于低速稳定层流。剪切应力诱导的分子和细胞反应的定义和验证使用各种突变小鼠模型。稳态层流诱导的经典剪切应力响应通常在BEC和LEC。然而，令人惊讶的是，只有LEC通过调节VEGF-A、VEGF-C、FGFR 3和p57/CDKN 1C基因显示出增强的细胞增殖。钙释放激活钙通道（calciumrelease-activatedcalcium channel，CRAC）的一个孔道亚基ORAI 1作为早期信号介导因子，被鉴定为诱导晶状体上皮细胞对流体流动的剪切应力表型和细胞增殖。从机制上讲，ORAI 1诱导KLF 2和KLF 4在流动激活的LEC中上调，并且两种KLF蛋白通过结合到基因的调节区来协同调节VEGF-A、VEGF-C、FGFR 3和p57。一致地，从Orai 1敲除胚胎新鲜分离的LEC显示KLF 2、KLF 4、VEGF-A、VEGF-C和FGFR 3的表达降低，以及p57的表达升高。因此，缺乏Orai 1、Klf 2或Klf 4的小鼠胚胎显示出显著降低的淋巴密度和受损的淋巴发育。我们的研究确定了层流激活LEC增殖的分子机制。
Lymphatic vessels function to drain interstitial fluid from a variety of tissues. Although shear stress generated by fluid flow is known to trigger lymphatic expansion and remodeling, the molecular basis underlying flow-induced lymphatic growth is unknown. We aimed to gain a better understanding of the mechanism by which laminar shear stress activates lymphatic proliferation. Primary endothelial cells from dermal blood and lymphatic vessels (BECs and LECs) were exposed to low-rate steady laminar flow. Shear stress-induced molecular and cellular responses were defined and verified using various mutant mouse models. Steady laminar flow induced the classic shear stress responses commonly in BECs and LECs. Surprisingly, however, only LECs showed enhanced cell proliferation by regulating the VEGF-A, VEGF-C, FGFR3, and p57/CDKN1C genes. As an early signal mediator, ORAI1, a pore subunit of the calcium release-activated calcium (CRAC) channel, was identified to induce the shear stress phenotypes and cell proliferation in LECs responding to the fluid flow. Mechanistically, ORAI1 induced upregulation of KLF2 and KLF4 in the flow-activated LECs and the two KLF proteins cooperate to regulate VEGF-A, VEGF-C, FGFR3 and p57 by binding to the regulatory regions of the genes. Consistently, freshly isolated LECs from Orai1 knockout embryos displayed reduced expression of KLF2, KLF4, VEGF-A, VEGF-C, and FGFR3, and elevated expression of p57. Accordingly, mouse embryos deficient of Orai1, Klf2, or Klf4 showed a significantly reduced lymphatic density and impaired lymphatic development. Our study identified a molecular mechanism for laminar flow-activated LEC proliferation.