El Gazzar M
Deparment of Medicine, University of Colorado Health Sciences Center, Denver, CO 80262, USA.
Inflamm Res. 2007 Apr;56(4):162-7. doi: 10.1007/s00011-006-6112-0.
As a late mediator of inflammation, high mobility group box 1 protein (HMGB1) amplifies the inflammatory responses to tissue injury and infection by inducing and extending the production of proinflammaory cytokines. The aim was to investigate whether HMGB1 mediates such effects by affecting the production of anti-inflammatory mediators.
The murine macrophage RAW 264.7 cells were stimulated with 0.5 microg/ml of LPS and the levels of HMGB1, TNFalpha, IL-1beta, IL-10 and TGF-beta1 in the culture supernatants were measured by ELISA. Also, the mRNA expression for IL-10 and TGF-beta1 was assessed by RT-PCR.
LPS induced HMGB1 release at 8 h and reached a peak at 48 h. Significant (p < 0.05) production of TNFalpha, IL-1beta, IL-10, and TGF-beta1 was seen after 8 h. However, while the levels of TNFalpha and IL-beta remained elevated, IL-10 and TGF-beta1 release markedly declined by 24 h after stimulation. When cells were stimulated in the presence of conditioned medium derived from a 24 h LPS-stimulated culture, the production of TNFalpha and IL-1beta was increased while IL-10 and TGF-beta1 release and mRNA transcripts were decreased. A neutralizing anti-HMGB1 antibody added to the conditioned media reveresed these responses.
HMGB1 modulates the inflammatory cascade in activated macrophages by inducing proinflammatory, while suppressing anti-inflammatory responses.
作为炎症的晚期介质，高迁移率族蛋白B1（HMGB1）通过诱导和延长促炎细胞因子的产生来放大对组织损伤和感染的炎症反应。本研究旨在探讨HMGB1是否通过影响抗炎介质的产生来介导上述效应。
用0.5μg/ml脂多糖（LPS）刺激小鼠巨噬细胞RAW 264.7，采用酶联免疫吸附测定（ELISA）法检测培养上清液中HMGB1、肿瘤坏死因子α（TNFα）、白细胞介素1β（IL-1β）、白细胞介素10（IL-10）和转化生长因子β1（TGF-β1）的水平。同时，采用逆转录-聚合酶链反应（RT-PCR）法评估IL-10和TGF-β1的mRNA表达。
LPS刺激8小时后诱导HMGB1释放，并在48小时达到峰值。8小时后可见TNFα、IL-1β、IL-10和TGF-β1显著（p<0.05）产生。然而，虽然TNFα和IL-β水平仍保持升高，但刺激后24小时IL-10和TGF-β1的释放明显下降。当细胞在来自24小时LPS刺激培养物的条件培养基存在下受到刺激时，TNFα和IL-1β的产生增加，而IL-10和TGF-β1的释放及mRNA转录物减少。向条件培养基中加入中和抗HMGB1抗体可逆转这些反应。
HMGB1通过诱导促炎反应同时抑制抗炎反应来调节活化巨噬细胞中的炎症级联反应。
