CDC42 Deletion Elicits Cerebral Vascular Malformations via Increased MEKK3-Dependent KLF4 Expression
CDC42 Deletion Elicits Cerebral Vascular Malformations via Increased MEKK3-Dependent KLF4 Expression
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DOI：
10.1161/circresaha.118.314300
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发表时间：
2019-04-12
影响因子：
20.1
通讯作者：
Gaengel, Konstantin
中科院分区：
文献类型：
--
作者：
Castro, Marco;Lavina, Barbara;Gaengel, Konstantin
目的：我们研究了CDC42(细胞分裂周期42)在血管形态发生中的作用及其在脑血管畸形发生中的相对重要性。方法和结果：为了避免通常与胚胎基因缺失相关的继发性全身效应，我们建立了一种内皮特异性的、可诱导的基因敲除方法来研究小鼠出生后的脑血管形成。出生后内皮细胞特异性的CDC42缺失会引起脑血管畸形，使人联想到脑海绵状畸形(CCM)。在细胞水平上，脑内皮细胞(ECs)中CDC42功能的丧失损害了它们的萌发、分支形态发生、轴向极性和在脑组织中的正常弥散。CDC42的干扰不会改变EC的增殖，但在大脑发育过程中EC增殖最明显的地方--出生后的小脑--会发生畸形，这表明自然发生的高EC增殖为这些畸形的出现提供了一种允许的状态。在机制上，内皮细胞中的CD42缺失引起MEKK3(丝裂原活化蛋白激酶3)-MEK5(丝裂原活化蛋白激酶5)-ERK5(细胞外信号调节激酶5)信号的增加，从而导致KLF(Kruppel-like factor2)和KLF4的有害过度表达，概括了CCM发病的标志性机制。通过遗传方法，我们证明了KLF4的协同激活降低了CDC42突变小鼠血管畸形的严重程度。此外，我们还发现CDC42与CCM相互作用，并且CCM3促进内皮细胞中CDC42的活性。结论：我们发现内皮特异性的CDC42缺失会导致CCM样脑血管畸形，而CDC42参与CCM信号网络，从而抑制MEKK3-MEK5-ERK5-KLF2/4通路。
Rationale: Aberrant formation of blood vessels precedes a broad spectrum of vascular complications; however, the cellular and molecular events governing vascular malformations are not yet fully understood.Objective: Here, we investigated the role of CDC42 (cell division cycle 42) during vascular morphogenesis and its relative importance for the development of cerebrovascular malformations.Methods and Results: To avoid secondary systemic effects often associated with embryonic gene deletion, we generated an endothelial-specific and inducible knockout approach to study postnatal vascularization of the mouse brain. Postnatal endothelial-specific deletion of Cdc42 elicits cerebrovascular malformations reminiscent of cerebral cavernous malformations (CCMs). At the cellular level, loss of CDC42 function in brain endothelial cells (ECs) impairs their sprouting, branching morphogenesis, axial polarity, and normal dispersion within the brain tissue. Disruption of CDC42 does not alter EC proliferation, but malformations occur where EC proliferation is the most pronounced during brain development-the postnatal cerebellum-indicating that a high, naturally occurring EC proliferation provides a permissive state for the appearance of these malformations. Mechanistically, CDC42 depletion in ECs elicited increased MEKK3 (mitogen-activated protein kinase kinase kinase 3)-MEK5 (mitogen-activated protein kinase kinase 5)-ERK5 (extracellular signal-regulated kinase 5) signaling and consequent detrimental overexpression of KLF (Kruppel-like factor) 2 and KLF4, recapitulating the hallmark mechanism for CCM pathogenesis. Through genetic approaches, we demonstrate that the coinactivation of Klf4 reduces the severity of vascular malformations in Cdc42 mutant mice. Moreover, we show that CDC42 interacts with CCMs and that CCM3 promotes CDC42 activity in ECs.Conclusions: We show that endothelial-specific deletion of Cdc42 elicits CCM-like cerebrovascular malformations and that CDC42 is engaged in the CCM signaling network to restrain the MEKK3-MEK5-ERK5-KLF2/4 pathway.