Cerebral Cavernous Malformation Proteins and MEKK3 Coordinately Modulate SMURF1 Abundance to Control RhoA-dependent Endothelial Cell Phenotypic State

Cerebral Cavernous Malformations (CCM), caused by loss of CCM1, CCM2 or CCM3 in endothelial cells (ECs), are leaky capillaries causing seizures and stroke. CCM protein loss gives overlapping changes in biomechanical and transcriptional properties of ECs, due to common RhoA-driven alterations in cytoskeletal organization and intracellular signaling. However, EC models of 3-D tube formation show loss of each CCM protein generates distinct morphological defects in tubular structures. Computational modeling, live-cell imaging and RNA sequencing revealed distinct functional roles of CCM1 and CCM3 in regulating EC-EC and EC-matrix interactions. CCM2 has an intermediate phenotype consistent with its interaction with CCM1 and CCM3. In ECs, CCM proteins regulate SMURF1 E3 ligase ubiquitination and degradation of RhoA. Loss of CCM proteins results in loss of SMURF1 and a concomitant increase of MEKK3, a negative regulator of SMURF1 expression. We propose CCM lesions develop because of dysregulated SMURF1 resulting in RhoA and MEKK3 gain-of-function. 29 experimental samples with replicates indicated in sample title

脑海绵状血管畸形（Cerebral Cavernous Malformations, CCM）是因内皮细胞（endothelial cells, ECs）中CCM1、CCM2或CCM3缺失所引发的疾病，以渗漏性毛细血管病变为核心病理表现，可诱发癫痫与脑卒中。CCM蛋白缺失会通过RhoA介导的细胞骨架组织与细胞内信号通路的共同改变，引发内皮细胞生物力学特性与转录特性的重叠性变化。但针对三维管腔形成的内皮细胞模型研究显示，不同CCM蛋白的缺失会对管腔结构造成各具特征的形态学缺陷。通过计算建模、活细胞成像与RNA测序技术，研究人员发现CCM1与CCM3在调控内皮细胞-内皮细胞及内皮细胞-细胞外基质相互作用中发挥着独特的功能作用；CCM2则呈现出中间表型，这与其同时与CCM1、CCM3存在相互作用的特性相符。在内皮细胞中，CCM蛋白可调控SMURF1 E3泛素连接酶（SMURF1 E3 ligase）对RhoA的泛素化与降解过程。CCM蛋白缺失会导致SMURF1表达水平下调，同时伴随其负调控因子MEKK3的表达升高。我们提出假说：CCM病变的发生源于SMURF1调控异常，进而引发RhoA与MEKK3的功能获得性改变。本数据集共包含29份实验样本，样本标题中标注了重复样本的相关信息。