Mehdi Syed J, Zhang Haihong, Sun Ravi W, Richter Gresham T, Strub Graham M
Arkansas Children's Research Institute (ACRI), Little Rock, AR 72202, USA.
Department of Otolaryngology-Head and Neck Surgery, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, AR 72202, USA.
Cells. 2024 Dec 21;13(24):2122. doi: 10.3390/cells13242122.
Extracranial arteriovenous malformations (eAVMs) are complex vascular lesions characterized by anomalous arteriovenous connections, vascular instability, and disruptions in endothelial cell (EC)-to-mural cell (MC) interactions. This study sought to determine whether eAVM-MCs could induce endothelial-to-mesenchymal transition (EndMT), a process known to disrupt vascular integrity, in the eAVM microenvironment. eAVM and paired control tissues were analyzed using RT-PCR for EC (, , and ) and EndMT-specific markers (, , , /. Immunohistochemistry (IHC) was also performed to analyze MC- (PDGFR-β and α-SMA), EC (CD31, CD34, and CDH5), and EndMT-specific markers (CDH2 and SNAI1) in sequential paraffin-embedded sections of eAVM patient biopsies and in adjacent normal tissue biopsies from the same patients. Furthermore, eAVM-MCs and MCs from normal paired tissues (NMCs) were then isolated from fresh human surgical samples using flow cytometry and co-cultured with normal human umbilical vein vascular endothelial cells (HUVECs), followed by analysis of CD31 by immunofluorescence. RT-PCR analysis did not show a significant difference in the expression of EC markers between eAVM tissues and controls, whereas expression of EndMT-specific markers was upregulated in eAVM tissues compared to controls. IHC of eAVMs and paired control tissues demonstrated regions of significant perivascular eAVM-MC expansion (PDGFR-β+, and α-SMA+) surrounding dilated, morphologically abnormal vessels. These regions contained endothelium undergoing EndMT as evidenced by loss of CD31, CD34, and CDH5 expression and upregulation of the EndMT-associated genes CDH2 and SNAI1. Isolated eAVM-MCs induced loss of CD31 in HUVECs when grown in co-culture, while NMCs did not. This study suggests that the eAVM endothelium surrounded by expanded eAVM-MCs undergoes EndMT, potentially leading to the formation of dilated and fragile vessels, and implicates the eAVM-MCs in EndMT initiation and eAVM pathology.
颅外动静脉畸形（eAVM）是一种复杂的血管病变，其特征为异常的动静脉连接、血管不稳定以及内皮细胞（EC）与壁细胞（MC）相互作用的破坏。本研究旨在确定eAVM-MC是否能在eAVM微环境中诱导内皮-间充质转化（EndMT），这是一个已知会破坏血管完整性的过程。使用逆转录聚合酶链反应（RT-PCR）分析eAVM和配对的对照组织中EC标志物（ 、 、 和 ）以及EndMT特异性标志物（ 、 、 、 / ）。还进行了免疫组织化学（IHC）分析，以检测eAVM患者活检组织及同一患者相邻正常组织活检的连续石蜡包埋切片中的MC标志物（血小板衍生生长因子受体-β（PDGFR-β）和α-平滑肌肌动蛋白（α-SMA））、EC标志物（CD31、CD34和钙黏蛋白5（CDH5））以及EndMT特异性标志物（钙黏蛋白2（CDH2）和锌指蛋白SNAI1）。此外，使用流式细胞术从新鲜的人类手术样本中分离出eAVM-MC和来自正常配对组织的MC（NMC），并与正常人脐静脉血管内皮细胞（HUVEC）共培养，随后通过免疫荧光分析CD31。RT-PCR分析显示，eAVM组织和对照之间EC标志物的表达没有显著差异，而与对照相比，EndMT特异性标志物在eAVM组织中的表达上调。eAVM及其配对对照组织的IHC显示，在扩张的、形态异常的血管周围存在明显的血管周围eAVM-MC扩张区域（PDGFR-β+和α-SMA+）。这些区域包含正在经历EndMT的内皮，表现为CD31、CD34和CDH5表达丧失以及EndMT相关基因CDH2和SNAI1上调。共培养时，分离出的eAVM-MC可诱导HUVEC中CD31丧失，而NMC则不会。本研究表明，被扩张的eAVM-MC包围的eAVM内皮会经历EndMT，这可能导致扩张且脆弱的血管形成，并提示eAVM-MC在EndMT起始和eAVM病理过程中起作用。
