Department of Reproductive Endocrinology, University Hospital Zurich, 8952 Schlieren, Switzerland.
ID Scientific IT Services, ETH Zurich, 8092 Zurich, Switzerland.
Cells. 2021 Sep 4;10(9):2314. doi: 10.3390/cells10092314.
Stroke is the third leading cause of mortality in women and it kills twice as many women as breast cancer. A key role in the pathophysiology of stroke plays the disruption of the blood-brain barrier (BBB) within the neurovascular unit. While estrogen induces vascular protective actions, its influence on stroke remains unclear. Moreover, experiments assessing its impact on endothelial cells to induce barrier integrity are non-conclusive. Since pericytes play an active role in regulating BBB integrity and function, we hypothesize that estradiol may influence BBB by regulating their activity. In this study using human brain vascular pericytes (HBVPs) we investigated the impact of estradiol on key pericyte functions known to influence BBB integrity. HBVPs expressed estrogen receptors (ER-α, ER-β and GPER) and treatment with estradiol (10 nM) inhibited basal cell migration but not proliferation. Since pericyte migration is a hallmark for BBB disruption following injury, infection and inflammation, we investigated the effects of estradiol on TNFα-induced PC migration. Importantly, estradiol prevented TNFα-induced pericyte migration and this effect was mimicked by PPT (ER-α agonist) and DPN (ER-β agonist), but not by G1 (GPR30 agonist). The modulatory effects of estradiol were abrogated by MPP and PHTPP, selective ER-α and ER-β antagonists, respectively, confirming the role of ER-α and ER-β in mediating the anti-migratory actions of estrogen. To delineate the intracellular mechanisms mediating the inhibitory actions of estradiol on PC migration, we investigated the role of AKT and MAPK activation. While estradiol consistently reduced the TNFα-induced MAPK and Akt phosphorylation, only the inhibition of MAPK, but not Akt, significantly abrogated the migratory actions of TNFα. In transendothelial electrical resistance measurements, estradiol induced barrier function (TEER) in human brain microvascular endothelial cells co-cultured with pericytes, but not in HBMECs cultured alone. Importantly, transcriptomics analysis of genes modulated by estradiol in pericytes showed downregulation of genes known to increase cell migration and upregulation of genes known to inhibit cell migration. Taken together, our findings provide the first evidence that estradiol modulates pericyte activity and thereby improves endothelial integrity.
中风是女性死亡的第三大原因，其导致的女性死亡人数是乳腺癌的两倍。在神经血管单元中，血脑屏障（BBB）的破坏在中风的病理生理学中起着关键作用。虽然雌激素诱导血管保护作用，但它对中风的影响尚不清楚。此外，评估其对诱导内皮细胞屏障完整性的影响的实验尚无定论。由于周细胞在调节 BBB 完整性和功能方面发挥着积极的作用，我们假设雌激素可能通过调节其活性来影响 BBB。在这项使用人脑血管周细胞（HBVPs）的研究中，我们研究了雌激素对已知影响 BBB 完整性的关键周细胞功能的影响。HBVPs 表达雌激素受体（ER-α、ER-β 和 GPER），用雌二醇（10 nM）处理可抑制基础细胞迁移，但不抑制增殖。由于周细胞迁移是损伤、感染和炎症后 BBB 破坏的标志，我们研究了雌二醇对 TNFα 诱导的 PC 迁移的影响。重要的是，雌二醇可防止 TNFα 诱导的周细胞迁移，而 PPT（ER-α 激动剂）和 DPN（ER-β 激动剂）可模拟这种作用，但 G1（GPR30 激动剂）则不行。用 MPP 和 PHTPP（分别为选择性 ER-α 和 ER-β 拮抗剂）阻断雌二醇的调节作用，证实了 ER-α 和 ER-β 在介导雌激素的抗迁移作用中的作用。为了描绘介导雌二醇对 PC 迁移的抑制作用的细胞内机制，我们研究了 AKT 和 MAPK 激活的作用。尽管雌二醇始终降低 TNFα 诱导的 MAPK 和 Akt 磷酸化，但只有 MAPK 的抑制，而不是 Akt 的抑制，显著阻断了 TNFα 的迁移作用。在跨内皮电阻测量中，雌二醇诱导与人脑微血管内皮细胞共培养的周细胞的屏障功能（TEER），但不在单独培养的 HBMECs 中诱导。重要的是，对雌二醇在周细胞中调节的基因进行转录组分析表明，下调已知增加细胞迁移的基因，并上调已知抑制细胞迁移的基因。综上所述，我们的研究结果首次提供了证据，表明雌二醇调节周细胞活性，从而改善内皮完整性。
