Dimasi David P, Pitson Stuart M, Bonder Claudine S
Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, South Australia, Australia.
School of Medicine, University of Adelaide, Adelaide, South Australia, Australia.
Microcirculation. 2016 Apr;23(3):248-65. doi: 10.1111/micc.12271.
A key mediator of vascular EC barrier integrity, S1P, is derived from phosphorylation of sphingosine by the SK-1 and SK-2. While previous work indicates that SK-1 can regulate EC barrier integrity, whether SK-2 has a similar role remains to be determined.
A cell impedance assay was used to assess human umbilical vein EC and bone marrow EC barrier integrity in vitro, with application of the SK inhibitors ABC294640, PF543, SKi, and MP-A08. In vivo studies were conducted using intravital microscopy to assess EC barrier integrity in SK-1 (Sphk1(-/-)) and SK-2 (Sphk2(-/-)) knock-out mice.
Only ABC294640 and MP-A08, which can both inhibit SK-2, caused a decrease in EC barrier integrity in vitro in both cell types. Intravital microscopy revealed that Sphk1(-/-) mice had reduced EC barrier integrity compared to WT mice, whereas no change was evident in Sphk2(-/-) mice.
Our data suggest that in vitro inhibition of SK-2, can compromise the integrity of the EC monolayer, while SK-1 exerts a more dominant control in vivo. These data may have clinical implications and could aid in the development of new treatments for disorders of vascular barrier function.
血管内皮细胞（EC）屏障完整性的关键介质鞘氨醇-1-磷酸（S1P）由鞘氨醇激酶1（SK-1）和鞘氨醇激酶2（SK-2）磷酸化鞘氨醇产生。虽然先前的研究表明SK-1可调节EC屏障完整性，但SK-2是否具有类似作用仍有待确定。
使用细胞阻抗测定法，通过应用SK抑制剂ABC294640、PF543、SKi和MP-A08，在体外评估人脐静脉内皮细胞和骨髓内皮细胞的屏障完整性。体内研究采用活体显微镜检查，评估SK-1基因敲除（Sphk1(-/-)）小鼠和SK-2基因敲除（Sphk2(-/-)）小鼠的内皮细胞屏障完整性。
仅能抑制SK-2的ABC294640和MP-A08，在体外均可导致两种细胞类型的内皮细胞屏障完整性降低。活体显微镜检查显示，与野生型小鼠相比，Sphk1(-/-)小鼠的内皮细胞屏障完整性降低，而Sphk2(-/-)小鼠未见明显变化。
我们的数据表明，体外抑制SK-2会损害内皮细胞单层的完整性，而SK-1在体内发挥更主要的调控作用。这些数据可能具有临床意义，并有助于开发针对血管屏障功能障碍的新疗法。
