Toll-like receptor 4 mediates inflammatory signaling by bacterial lipopolysaccharide in human hepatic stellate cells
Toll-like receptor 4 mediates inflammatory signaling by bacterial lipopolysaccharide in human hepatic stellate cells
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DOI：
10.1053/jhep.2003.50182
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发表时间：
2003-05-01
期刊：
影响因子：
13.5
通讯作者：
Brenner, DA
中科院分区：
文献类型：
--
作者：
Paik, YH;Schwabe, RF;Brenner, DA
细菌脂多糖（LPS）刺激库普弗细胞并参与酒精性肝损伤的发病机制。然而，LPS 是否直接影响肝星状细胞 (HSC)（受损肝脏中主要的纤维化细胞类型）尚不清楚。本研究表征了活化的人 HSC 中 LPS 诱导的信号转导和促炎基因表达。培养激活的 HSC 和从丙型肝炎病毒诱导的肝硬化患者中分离的 HSC 表达 LPS 相关信号分子，包括 CD14、Toll 样受体 (TLR) 4 和 MD2。用 LPS 刺激培养物激活的 HSC 会导致 NF-kappaB 快速而显着的激活，通过 IkappaB 激酶 (IKK) 体外激酶测定、IkappaBα 稳态水平、p65 核易位、NF-kappaB 依赖性荧光素酶报告基因测定和电泳迁移率变动测定进行评估。脂质 A 以相似的方式诱导 NF-kappaB 活化 LPS 和脂质 A 诱导的 NF-kappaB 活化均可通过与抗 TLR4 阻断抗体 (HTA125) 或多粘菌素 B 预孵育来阻断。脂质 A 在 TILR4 充足 (C3H/OuJ) 小鼠的 HSC 中诱导 NF-kappaB 活化，但不能诱导 TILR4 缺陷小鼠的 HSC 活化(C3H/HeJ) 小鼠。根据体外激酶测定的评估，LPS 还可以激活 c-Jun N 末端激酶 (JNK)。 LPS 上调 IL-8 和 MCP-1 基因表达和分泌。 LPS 诱导的 IL-8 分泌被 IkappaB 超级阻遏物 (Ad5IkappaB) 完全抑制，并被特定 JNK 抑制剂 SP600125 部分抑制。 LPS 还上调细胞表面 ICAM-1 和 VCAM-1 的表达。总之，人类活化的 HSC 利用 TLR4 信号转导级联的成分来刺激 NF-kappaB 和 JNK，并上调趋化因子和粘附分子。因此，HSC 是 LPS 诱导的肝损伤的潜在介质。
Bacterial lipopolysaccharide (LPS) stimulates Kupffer cells and participates in the pathogenesis of alcohol-induced liver injury. However, it is unknown whether LPS directly affects hepatic stellate cells (HSCs), the main fibrogenic cell type in the injured liver. This study characterizes LPS-induced signal transduction and proinflammatory gene expression in activated human HSCs. Culture-activated HSCs and HSCs isolated from patients with hepatitis C virus-induced cirrhosis express LPS-associated signaling molecules, including CD14, toll-like receptor (TLR) 4, and MD2. Stimulation of culture-activated HSCs with LPS results in a rapid and marked activation of NF-kappaB, as assessed by in vitro kinase assays for IkappaB kinase (IKK), IkappaBalpha steadystate levels, p65 nuclear translocation, NF-kappaB-dependent luciferase reporter gene assays, and electrophoretic mobility shift assays. Lipid A induces NF-kappaB activation in asimilar manner Both LPS- and lipidA-induced NF-kappaB activation is blocked by preincubation with either anti-TLR4 blocking antibody (HTA125) or Polymyxin B. Lipid A induces NF-kappaB activation in HSCs from TILR4-sufficient (C3H/OuJ) mice but not from TILR4-deficient (C3H/HeJ) mice. LPS also activates c-Jun N-terminal kinase (JNK), as assessed by in vitro kinase assays. LPS up-regulates IL-8 and MCP-1 gene expression and secretion. LPS-induced IL-8 secretion is completely inhibited by the IkappaB super repressor (Ad5IkappaB) and partially inhibited by a specificJNK inhibitor, SP600125. LPS also up-regulates cell surface expression of ICAM-1 and VCAM-1. In conclusion, human activated HSCs utilize components of TLR4 signal transduction cascade to stimulate NF-kappaB and JNK and up-regulate chemokines and adhesion molecules. Thus, HSCs are a potential mediator of LPS-induced liver injury.