Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, Virginia.
Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania; Department, Thornton Tomasetti, New York City, New York.
Biophys J. 2022 Feb 15;121(4):620-628. doi: 10.1016/j.bpj.2022.01.004. Epub 2022 Jan 6.
Hutchinson-Gilford progeria syndrome (HGPS) is a rare premature aging disease caused by a single-point mutation in the lamin A gene, resulting in a truncated and farnesylated form of lamin A. This mutant lamin A protein, known as progerin, accumulates at the periphery of the nuclear lamina, resulting in both an abnormal nuclear morphology and nuclear stiffening. Patients with HGPS experience rapid onset of atherosclerosis, with death from heart attack or stroke as teenagers. Progerin expression has been shown to cause dysfunction in both vascular smooth muscle cells and endothelial cells (ECs). In this study, we examined how progerin-expressing endothelial cells adapt to fluid shear stress, the principal mechanical force from blood flow. We compared the response to shear stress for progerin-expressing, wild-type lamin A overexpressing, and control endothelial cells to physiological levels of fluid shear stress. Additionally, we also knocked down ZMPSTE24 in endothelial cells, which results in increased farnesylation of lamin A and similar phenotypes to HGPS. Our results showed that endothelial cells either overexpressing progerin or with ZMPSTE24 knockdown were unable to adapt to shear stress, experiencing significant cell loss at a longer duration of exposure to shear stress (3 days). Endothelial cells overexpressing wild-type lamin A also exhibited similar impairments in adaptation to shear stress, including similar levels of cell loss. Quantification of nuclear morphology showed that progerin-expressing endothelial cells had similar nuclear abnormalities in both static and shear conditions. Treatment of progerin-expressing cells and ZMPSTE24 KD cells with lonafarnib and methystat, drugs previously shown to improve HGPS nuclear morphology, resulted in improvements in adaptation to shear stress. Additionally, the prealignment of cells to shear stress before progerin-expression prevented cell loss. Our results demonstrate that changes in nuclear lamins can affect the ability of endothelial cells to properly adapt to shear stress.
亨廷顿舞蹈病-早老综合征（HGPS）是一种罕见的过早衰老疾病，由 lamin A 基因突变引起，导致 lamin A 截短和法尼基化。这种突变的 lamin A 蛋白，称为 progerin，在核膜层的外周积累，导致核形态异常和核僵硬。HGPS 患者会迅速出现动脉粥样硬化，青少年时期死于心脏病发作或中风。已经表明 progerin 的表达会导致血管平滑肌细胞和内皮细胞（ECs）功能障碍。在这项研究中，我们研究了表达 progerin 的内皮细胞如何适应流体切应力，这是血流产生的主要机械力。我们比较了表达 progerin 的内皮细胞、过表达野生型 lamin A 的内皮细胞和对照内皮细胞对生理水平的流体切应力的反应。此外，我们还敲低了内皮细胞中的 ZMPSTE24，这会导致 lamin A 的法尼基化增加，并出现类似于 HGPS 的表型。我们的结果表明，过表达 progerin 或 ZMPSTE24 敲低的内皮细胞无法适应切应力，在更长时间暴露于切应力（3 天）时会经历显著的细胞损失。过表达野生型 lamin A 的内皮细胞在适应切应力方面也表现出类似的损伤，包括类似水平的细胞损失。核形态的定量分析表明，表达 progerin 的内皮细胞在静态和切应力条件下都有类似的核异常。用 lonafarnib 和 methystat 处理表达 progerin 的细胞和 ZMPSTE24 KD 细胞，这两种药物以前被证明可以改善 HGPS 的核形态，导致对切应力的适应能力提高。此外，在表达 progerin 之前将细胞预先对准切应力可以防止细胞损失。我们的结果表明，核层粘连蛋白的变化会影响内皮细胞正确适应切应力的能力。
