Department of Laboratory Medicine, University of California, San Francisco, San Francisco, CA.
Department of Pediatrics, University of California, San Francisco, San Francisco, CA.
Blood Adv. 2023 Apr 11;7(7):1241-1257. doi: 10.1182/bloodadvances.2022007409.
Platelets (PLTs) stored at 4°C exhibit equivalent or superior hemostatic function compared with 22°C PLTs, but have shorter circulation times and a decreased ability to modulate vascular permeability. These differences may be due to morphological changes and storage-induced activation. Using a proteomics-based approach, we found that 4°C-stored PLTs express decreased α-tubulin, a key PLT structural protein. PLT activation is characterized by α-tubulin deacetylation, which is regulated by histone deacetylase-6 (HDAC-6). We hypothesized that inhibition of HDAC-6 in stored PLTs will improve their ability to regulate vascular permeability through reduced activation and α-tubulin deacetylation. In an in vivo model of vascular permeability, treatment of 4°C PLTs with the HDAC-6 inhibitor tubacin enhanced the vasculoprotective properties of untreated 4°C PLTs. 4°C PLT circulation, however, was unchanged by tubacin treatment, suggesting that circulation time may not be a critical factor in determining the vasculoprotective effects of PLTs. Assessing the factor content of stored PLTs revealed that angiopoietin-1 (Ang-1) increased in 4°C PLTs over time, which was further enhanced by tubacin treatment. In addition, angiopoietin-2, an inducer of vascular leak and antagonist of Ang-1, inhibited PLT barrier protection, suggesting involvement of the Tie-2 pathway. This study demonstrates that HDAC-6 inhibition with tubacin attenuates the diminished vasculo-protective properties of 4°C PLTs, and these properties may be independent of PLT circulation time.
在 4°C 下储存的血小板 (PLT) 表现出与 22°C PLT 相当或更好的止血功能，但循环时间更短，调节血管通透性的能力下降。这些差异可能是由于形态变化和储存诱导的激活。使用基于蛋白质组学的方法，我们发现 4°C 储存的 PLT 表达减少的α-微管蛋白，这是一种关键的 PLT 结构蛋白。PLT 的激活特征是α-微管蛋白去乙酰化，这受组蛋白去乙酰化酶-6 (HDAC-6) 调控。我们假设在储存的 PLT 中抑制 HDAC-6 将通过减少激活和α-微管蛋白去乙酰化来改善其调节血管通透性的能力。在血管通透性的体内模型中，用 HDAC-6 抑制剂 tubacin 处理 4°C PLT 增强了未经处理的 4°C PLT 的血管保护特性。然而，4°C PLT 的循环不受 tubacin 处理的影响，这表明循环时间可能不是决定 PLT 血管保护作用的关键因素。评估储存的 PLT 的因子含量显示，Angiopoietin-1 (Ang-1) 随时间在 4°C PLT 中增加，并用 tubacin 处理进一步增强。此外，血管渗漏诱导因子和 Ang-1 的拮抗剂血管生成素-2 抑制 PLT 屏障保护，提示 Tie-2 途径的参与。这项研究表明，用 tubacin 抑制 HDAC-6 可减轻 4°C PLT 减弱的血管保护特性，并且这些特性可能与 PLT 循环时间无关。
