Waithe O'lisa Yaa, Anderson Aliyah, Muthusamy Saravanakumar, Seplovich Gabriela M, Tharakan Binu
Department of Surgery and Neuroscience Institute, Morehouse School of Medicine, Atlanta, Georgia, USA.
Microcirculation. 2025 Jul;32(5):e70019. doi: 10.1111/micc.70019.
The amino acid homocysteine (HCY) has been implicated in the pathobiology of several conditions, including spaceflight-associated neuro-ocular syndrome (SANS)-a collection of symptoms affecting near vision in astronauts. Blood-retinal barrier (BRB) and blood-brain barrier (BBB) dysfunctions are implicated in the pathobiology of SANS. Our objective was to assess how HCY affects BRB/BBB permeability and the role of the NLRP3 inflammasome in the modulation of such effects.
Human brain and retinal microvascular endothelial cells (HBMECs and HRMECs) were treated with 100 μM HCY alone or in conjunction with NLRP3 inflammasome inhibitor MCC950 at 1 μM. The assays performed included fluorometric assays to measure cell viability, an enzyme assay for caspase-1, expression of BRB/BBB tight junction protein zonula occludens-1 (ZO-1) by RT-PCR, and barrier permeability using FITC-dextran.
In HRMECs and HBMECs, HCY-induced endothelial monolayer hyperpermeability significantly (p < 0.05). In HBMECs, the effect was attenuated by MCC950 (p < 0.05). Increased Caspase-1 activity was observed in both cell types following the addition of HCY. Following HCY addition, gene expression results denoting barrier damage were observed, particularly that of ZO-1 (p < 0.05).
HCY induces hyperpermeability in retinal and brain endothelial cells. NLRP3-mediation in HCY-induced microvascular permeability is prominent in brain endothelial cells compared to retinal endothelial cells.
氨基酸同型半胱氨酸（HCY）与多种病症的病理生物学有关，包括航天相关神经-眼综合征（SANS）——一组影响宇航员近视力的症状。血视网膜屏障（BRB）和血脑屏障（BBB）功能障碍与SANS的病理生物学有关。我们的目的是评估HCY如何影响BRB/BBB通透性以及NLRP3炎性小体在调节此类作用中的作用。
用人脑和视网膜微血管内皮细胞（HBMECs和HRMECs）分别单独用100μM HCY处理，或与1μM的NLRP3炎性小体抑制剂MCC950联合处理。所进行的检测包括用于测量细胞活力的荧光检测、半胱天冬酶-1的酶检测、通过逆转录聚合酶链反应检测BRB/BBB紧密连接蛋白闭合蛋白-1（ZO-1）的表达，以及使用异硫氰酸荧光素-葡聚糖检测屏障通透性。
在HRMECs和HBMECs中，HCY诱导的内皮细胞单层通透性显著增加（p<0.05）。在HBMECs中该作用被MCC950减弱（p<0.05）。添加HCY后，在两种细胞类型中均观察到半胱天冬酶-1活性增加。添加HCY后，观察到表明屏障损伤的基因表达结果，特别是ZO-1的表达（p<0.05）。
HCY诱导视网膜和脑内皮细胞通透性增加。与视网膜内皮细胞相比，NLRP3在HCY诱导的微血管通透性中的介导作用在脑内皮细胞中更为突出。
