Department of Biomedical Engineering, Rowan University, Glassboro, NJ, USA.
Department of Pathology and Laboratory Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, USA.
J Neuroimmune Pharmacol. 2021 Dec;16(4):722-728. doi: 10.1007/s11481-021-10029-0. Epub 2021 Oct 23.
The SARS-CoV-2 spike protein has been shown to disrupt blood-brain barrier (BBB) function, but its pathogenic mechanism of action is unknown. Whether angiotensin converting enzyme 2 (ACE2), the viral binding site for SARS-CoV-2, contributes to the spike protein-induced barrier disruption also remains unclear. Here, a 3D-BBB microfluidic model was used to interrogate mechanisms by which the spike protein may facilitate barrier dysfunction. The spike protein upregulated the expression of ACE2 in response to laminar shear stress. Moreover, interrogating the role of ACE2 showed that knock-down affected endothelial barrier properties. These results identify a possible role of ACE2 in barrier homeostasis. Analysis of RhoA, a key molecule in regulating endothelial cytoskeleton and tight junction complex dynamics, reveals that the spike protein triggers RhoA activation. Inhibition of RhoA with C3 transferase rescues its effect on tight junction disassembly. Overall, these results indicate a possible means by which the engagement of SARS-CoV-2 with ACE2 facilitates disruption of the BBB via RhoA activation. Understanding how SARS-CoV-2 dysregulates the BBB may lead to strategies to prevent the neurological deficits seen in COVID-19 patients.
SARS-CoV-2 的刺突蛋白已被证明会破坏血脑屏障（BBB）的功能，但其致病作用机制尚不清楚。血管紧张素转换酶 2（ACE2）是否是 SARS-CoV-2 的病毒结合位点，也不清楚其是否有助于刺突蛋白诱导的屏障破坏。在这里，使用 3D-BBB 微流控模型来研究刺突蛋白可能促进屏障功能障碍的机制。刺突蛋白在上皮细胞层切应力的刺激下上调 ACE2 的表达。此外，研究 ACE2 的作用表明，敲低 ACE2 会影响内皮屏障特性。这些结果确定了 ACE2 在屏障稳态中的可能作用。分析 RhoA，一种调节内皮细胞细胞骨架和紧密连接复合物动力学的关键分子，表明刺突蛋白触发 RhoA 的激活。用 C3 转移酶抑制 RhoA 可挽救其对紧密连接解聚的作用。总的来说，这些结果表明，SARS-CoV-2 与 ACE2 的结合可能通过 RhoA 激活促进 BBB 的破坏。了解 SARS-CoV-2 如何使 BBB 失调可能会导致预防 COVID-19 患者出现神经功能缺损的策略。
