TLR4-Dependent Secretion by Hepatic Stellate Cells of the Neutrophil-Chemoattractant CXCL1 Mediates Liver Response to Gut Microbiota.
TLR4-Dependent Secretion by Hepatic Stellate Cells of the Neutrophil-Chemoattractant CXCL1 Mediates Liver Response to Gut Microbiota.
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DOI：
10.1371/journal.pone.0151063
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发表时间：
2016
期刊：
影响因子：
3.7
通讯作者：
Crispe IN
中科院分区：
文献类型：
--
作者：
Bigorgne AE;John B;Ebrahimkhani MR;Shimizu-Albergine M;Campbell JS;Crispe IN
肠道微生物群显着影响肝脏免疫。对于肝细胞在稳定状态下介导肠道微生物识别的精确机制知之甚少。在这里，我们测试了特定肝细胞群作为传感器的假设，我们的目的是破译 TLR4 通路激活介导肝脏对肠道微生物群反应的机制。使用微阵列，我们比较了 WT 小鼠与 TLR4 缺陷小鼠的总肝脏基因表达。我们对主要候选蛋白 CXCL1 进行了原位定位。通过基于细胞分选的创新技术，我们从同一肝脏中收获了 KC、LSEC 和 HSC 的富集部分。对低水平 LPS (1ng/mL) 的细胞因子分泌谱进行定量。在 TLR4 激活后，体外测定了星状细胞衍生的 CXCL1 对中性粒细胞的趋化活性。 TLR4 缺陷的肝脏会降低一种独特的趋化因子 CXCL1 的水平，并随后导致中性粒细胞计数减少。肠道微生物群的消耗模仿了 TLR4 缺陷表型，即肝脏中中性粒细胞计数减少。所有肝细胞均对低水平的 LPS 产生反应，但肝星状细胞是 CXCL1 趋化水平的主要来源。中性粒细胞向分泌型肝星状细胞迁移需要 TLR4 依赖的 CXCL1 分泌。通过显示 TLR4 的特异性激活和一种主要功能性趋化因子 CXCL1（人 IL-8- 的同源物）的分泌，我们阐明了一种新机制，其中肝星状细胞在稳态下肝脏识别肠道微生物中发挥核心作用。
The gut microbiota significantly influences hepatic immunity. Little is known on the precise mechanism by which liver cells mediate recognition of gut microbes at steady state. Here we tested the hypothesis that a specific liver cell population was the sensor and we aimed at deciphering the mechanism by which the activation of TLR4 pathway would mediate liver response to gut microbiota. Using microarrays, we compared total liver gene expression in WT versus TLR4 deficient mice. We performed in situ localization of the major candidate protein, CXCL1. With an innovative technique based on cell sorting, we harvested enriched fractions of KCs, LSECs and HSCs from the same liver. The cytokine secretion profile was quantified in response to low levels of LPS (1ng/mL). Chemotactic activity of stellate cell-derived CXCL1 was assayed in vitro on neutrophils upon TLR4 activation. TLR4 deficient liver had reduced levels of one unique chemokine, CXCL1 and subsequent decreased of neutrophil counts. Depletion of gut microbiota mimicked TLR4 deficient phenotype, i.e., decreased neutrophils counts in the liver. All liver cells were responsive to low levels of LPS, but hepatic stellate cells were the major source of chemotactic levels of CXCL1. Neutrophil migration towards secretory hepatic stellate cells required the TLR4 dependent secretion of CXCL1. Showing the specific activation of TLR4 and the secretion of one major functional chemokine—CXCL1, the homolog of human IL-8-, we elucidate a new mechanism in which Hepatic Stellate Cells play a central role in the recognition of gut microbes by the liver at steady state.