Department of Physiology, China Pharmaceutical University, Tongjia Xiang 24, Nanjing, Jiangsu 210009, People's Republic of China.
Atherosclerosis. 2011 Nov;219(1):40-8. doi: 10.1016/j.atherosclerosis.2011.07.010. Epub 2011 Jul 20.
We investigated whether 8-dihydroxy-3-methyl-isochromanone (XJP-1), a novel angiotensin-converting enzyme inhibitor (ACEI), exhibited inhibitory activity to lipopolysaccharide (LPS)-accelerated vascular inflammation.
Human umbilical vein endothelial cells (HUVECs) were isolated from human umbilical cords and cultured. The direct effect of XJP-1 on the activation of endothelial cells was measured using MTT assay. Nitric oxide (NO) in the culture medium was measured using Griess method. The expression of cell adhesion molecules (ICAM-1 and VCAM-1) was determined by flow cytometry and RT-PCR. The protein expression levels of tumor necrosis factor-α (TNF-α), monocyte chemotactic protein (MCP)-1, and endothelin-1 (ET-1) secretion were measured using ELISA. Quantitative analysis of eNOS, iNOS, inhibitory factor NF-κB (IκB) and MAPKs were determined using Western blot analysis. The translocation of NF-κB from the cytoplasm to the nucleus was determined using immunofluorescence.
XJP-1 significantly inhibited LPS-mediated endothelial cell dysfunction, as measured by NO production, iNOS expression, adhesion molecule (ICAM-1, VCAM-1) expression, and chemokine (TNF-α, MCP-1) production in vitro. It up-regulated eNOS expression in the same experimental setting. XJP-1 alone was found non-cytotoxic at the concentration up to 1000μM. The mechanistic investigations of XJP-1 suppression LPS-induced inflammation in HUVECs revealed that XJP-1 blocked NF-κB nuclear entry in an IκB-dependent manner, as well as inhibited MAPK activation induced by LPS. XJP-1 reduced endothelin-1 secretion and increased nitric oxide metabolite production by HUVECs. However, the effect of XJP-1 on nitric oxide and endothelin-1 metabolite production is mediated by the activation of bradykinin B(2) receptor being counteracted, at least in part, by a specific antagonist.
XJP-1 inhibited LPS-induced cytotoxicity and inflammatory response. The mechanism underlying this protective effect might be related to the inhibition of MAPK and NF-κB signaling pathway activation, suggesting the potential inhibition of the atherosclerotic process by suppressing the expression of chemoattractant molecules and monocyte adhesion. XJP-1 also has an effect in improving endothelin-1 through activating bradykinin B(2) receptor. These findings indicated that XJP-1 is potentially a novel therapeutic candidate for the treatment of atherosclerosis.
研究新型血管紧张素转化酶抑制剂（ACEI）8-二羟基-3-甲基异苯并呋喃-1（3H）-酮（XJP-1）是否具有抑制脂多糖（LPS）加速血管炎症的作用。
从人脐带中分离并培养人脐静脉内皮细胞（HUVEC）。采用 MTT 法测定 XJP-1 对内皮细胞激活的直接作用。用格里斯法测定培养基中一氧化氮（NO）的含量。采用流式细胞术和 RT-PCR 测定细胞间黏附分子（ICAM-1 和 VCAM-1）的表达。采用 ELISA 法测定肿瘤坏死因子-α（TNF-α）、单核细胞趋化蛋白-1（MCP-1）和内皮素-1（ET-1）的分泌蛋白表达水平。采用 Western blot 分析定量检测内皮型一氧化氮合酶（eNOS）、诱导型一氧化氮合酶（iNOS）、抑制因子 NF-κB（IκB）和 MAPKs 的表达。采用免疫荧光法测定 NF-κB 从细胞质向核内的转位。
XJP-1 显著抑制 LPS 介导的内皮细胞功能障碍，表现在体外 NO 生成、iNOS 表达、黏附分子（ICAM-1、VCAM-1）表达和趋化因子（TNF-α、MCP-1）产生方面。在相同的实验条件下，XJP-1 还能上调 eNOS 的表达。在高达 1000μM 的浓度下，XJP-1 本身无细胞毒性。XJP-1 抑制 LPS 诱导的 HUVECs 炎症的机制研究表明，XJP-1 通过 IκB 依赖性方式阻断 NF-κB 核内进入，并抑制 LPS 诱导的 MAPK 激活。XJP-1 减少内皮素-1 的分泌并增加 HUVECs 中一氧化氮代谢物的产生。然而，XJP-1 对一氧化氮和内皮素-1 代谢物产生的影响是通过激活缓激肽 B2 受体介导的，至少部分被特异性拮抗剂拮抗。
XJP-1 抑制 LPS 诱导的细胞毒性和炎症反应。这种保护作用的机制可能与 MAPK 和 NF-κB 信号通路激活的抑制有关，提示通过抑制趋化因子分子和单核细胞黏附的表达，抑制动脉粥样硬化过程的发生。XJP-1 还通过激活缓激肽 B2 受体对内皮素-1 有改善作用。这些发现表明，XJP-1 可能是一种治疗动脉粥样硬化的新型治疗候选药物。
