Departments of Emergency Medicine.
Pharmacology.
Shock. 2024 Nov 1;62(5):728-735. doi: 10.1097/SHK.0000000000002461. Epub 2024 Aug 28.
Objective : Vascular endothelial cells (ECs) sense and respond to both trauma factors (histone proteins) and sepsis signals (bacterial lipopolysaccharide, LPS) with elevations in calcium (Ca 2+ ), but it is not clear if the patterns of activation are similar or different. We hypothesized that within seconds of exposure, histones but not LPS would produce a large EC Ca 2+ response. We also hypothesized that histones would produce different spatio-temporal patterns of Ca 2+ events in veins than in arteries. Methods : We studied cultured ECs (EA.hy926) and native endothelial cells from surgically opened murine blood vessels. High-speed live cell imaging of Ca 2+ events were acquired for 5 min before and after stimulation of cultured ECs with histones or LPS alone or in combination. Histone-induced EC Ca 2+ events were also compared in native endothelial cells from resistance-sized arteries and veins. Ca 2+ activity was quantified as "Ca 2+ prevalence" using custom spatiotemporal analysis. Additionally, cultured ECs were collected after 6 h of exposure to histones or LPS for RNA sequencing. Results : ECs-both in culture and in blood vessels-rapidly increased Ca 2+ activity within seconds of histone exposure. In contrast, LPS exposure produced only a slight increase in Ca 2+ activity in cultured ECs and no effect on blood vessels over 5-min recording periods. Histones evoked large aberrant Ca 2+ events (>30 s in duration) in both veins and arteries, but with different spatio-temporal patterns. Ca 2+ activity in arterial ECs often appeared as "rosettes", with Ca 2+ events that propagated from one cell to all adjacent surrounding cells. In veins, ECs responded individually without spreading. Surprisingly, exposure of cultured ECs to LPS for 5 min before histones potentiated EC Ca 2+ activity by an order of magnitude. Exposure of ECs to histones or LPS both increased gene expression, but different mRNAs were induced. Conclusions : LPS and histones activate ECs through mechanisms that are distinct and additive; only histones produce large aberrant Ca 2+ events. ECs in arteries and veins display different patterns of Ca 2+ responses to histones.
血管内皮细胞 (ECs) 可以感知和响应创伤因素（组蛋白蛋白）和脓毒症信号（细菌脂多糖，LPS），导致钙离子 (Ca 2+ ) 升高，但尚不清楚其激活模式是否相似或不同。我们假设，在暴露后的几秒钟内，组蛋白而不是 LPS 会引起 EC Ca 2+ 的大量反应。我们还假设，组蛋白会在静脉中产生不同于动脉的不同时空 Ca 2+ 事件模式。方法：我们研究了培养的 ECs（EA.hy926）和从手术切开的鼠血管中分离的内皮细胞。在用组蛋白或 LPS 单独或联合刺激培养的 ECs 之前和之后，用高速活细胞成像获取 Ca 2+ 事件 5 分钟。还比较了来自阻力大小的动脉和静脉的天然内皮细胞中组蛋白诱导的 EC Ca 2+ 事件。使用自定义时空分析将 Ca 2+ 活性量化为“Ca 2+ 流行率”。此外，在用组蛋白或 LPS 孵育 6 小时后收集培养的 ECs 进行 RNA 测序。结果：ECs-无论是在培养物中还是在血管中-在暴露于组蛋白后的几秒钟内迅速增加 Ca 2+ 活性。相比之下，在培养的 ECs 中，LPS 暴露仅轻微增加 Ca 2+ 活性，在 5 分钟记录期间对血管无影响。组蛋白在静脉和动脉中都引起了大的异常 Ca 2+ 事件（持续时间超过 30 秒），但具有不同的时空模式。动脉 ECs 中的 Ca 2+ 活动通常表现为“玫瑰花结”，Ca 2+ 事件从一个细胞传播到所有相邻的周围细胞。在静脉中，细胞单独反应而不扩散。令人惊讶的是，在用组蛋白孵育培养的 ECs 5 分钟之前用 LPS 孵育会使 EC Ca 2+ 活性增强一个数量级。用组蛋白或 LPS 孵育 ECs 均会增加基因表达，但诱导的 mRNAs 不同。结论：LPS 和组蛋白通过不同且相加的机制激活 ECs；只有组蛋白产生大的异常 Ca 2+ 事件。动脉和静脉中的 ECs 对组蛋白表现出不同的 Ca 2+ 反应模式。
