Aw Wen Yih, Sawhney Aanya, Rathod Mitesh, Whitworth Chloe P, Doherty Elizabeth L, Madden Ethan, Lu Jingming, Westphal Kaden, Stack Ryan, Polacheck William J
Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill, North Carolina 27514, USA.
Department of Genetics and Molecular Biology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina 27599, USA.
APL Bioeng. 2025 Feb 5;9(1):016106. doi: 10.1063/5.0234507. eCollection 2025 Mar.
Somatic activating mutations in are common drivers of vascular and lymphatic malformations. Despite common biophysical signatures of tissues susceptible to lesion formation, including compliant extracellular matrix and low rates of perfusion, lesions vary in clinical presentation from localized cystic dilatation to diffuse and infiltrative vascular dysplasia. The mechanisms driving the differences in disease severity and variability in clinical presentation and the role of the biophysical microenvironment in potentiating progression are poorly understood. Here, we investigate the role of hemodynamic forces and the biophysical microenvironment in the pathophysiology of vascular malformations (VMs), and we identify hemodynamic shear stress and defective endothelial cell mechanotransduction as key regulators of lesion progression. We found that constitutive PI3K activation impaired flow-mediated endothelial cell alignment and barrier function. We show that defective shear stress sensing in endothelial cells is associated with reduced myosin light chain phosphorylation, junctional instability, and defective recruitment of vinculin to cell-cell junctions. Using three dimensional (3D) microfluidic models of the vasculature, we demonstrate that microvessels apply reduced traction forces and are unaffected by flow interruption. We further found that draining transmural flow resulted in increased sprouting and invasion responses in microvessels. Mechanistically, constitutive PI3K activation decreased cellular and nuclear elasticity resulting in defective cellular tensional homeostasis in endothelial cells which may underlie vascular dilation, tissue hyperplasia, and hypersprouting in -driven venous and lymphatic malformations. Together, these results suggest that defective nuclear mechanics, impaired cellular mechanotransduction, and maladaptive hemodynamic responses contribute to the development and progression of -driven vascular malformations.
体细胞激活突变是血管和淋巴管畸形的常见驱动因素。尽管易发生病变的组织具有共同的生物物理特征，包括顺应性细胞外基质和低灌注率，但病变的临床表现各不相同，从局限性囊性扩张到弥漫性浸润性血管发育异常。导致疾病严重程度差异和临床表现变异性的机制以及生物物理微环境在促进疾病进展中的作用尚不清楚。在这里，我们研究了血流动力学力和生物物理微环境在血管畸形（VMs）病理生理学中的作用，并确定血流动力学剪切应力和内皮细胞机械转导缺陷是病变进展的关键调节因素。我们发现组成型PI3K激活会损害血流介导的内皮细胞排列和屏障功能。我们表明，内皮细胞中剪切应力感知缺陷与肌球蛋白轻链磷酸化减少、连接不稳定以及纽蛋白向细胞间连接的募集缺陷有关。使用血管的三维（3D）微流体模型，我们证明微静脉施加的牵引力降低，并且不受血流中断的影响。我们进一步发现，引流跨壁血流会导致微静脉中芽生和侵袭反应增加。从机制上讲，组成型PI3K激活会降低细胞和细胞核弹性，导致内皮细胞中细胞张力稳态缺陷，这可能是PI3K驱动的静脉和淋巴管畸形中血管扩张、组织增生和过度芽生的基础。总之，这些结果表明，核力学缺陷、细胞机械转导受损和适应不良的血流动力学反应有助于PI3K驱动的血管畸形的发生和发展。
