Department of Burns, the 3rd Xiangya Hospital, Central South University, Changsha, China.
J Surg Res. 2013 Nov;185(1):319-28. doi: 10.1016/j.jss.2013.05.062. Epub 2013 Jun 10.
High-mobility group box 1 protein (HMGB1), a downstream inflammatory response modifier in sepsis and endotoxemia, alters endotoxin tolerance by affecting cellular hyporesponsiveness and tumor necrosis factor α and interleukin 1 production.
Endogenous HMGB1 signaling mechanisms during low-dose lipopolysaccharide (LPS)-induced endotoxin tolerance were investigated.
BALB/c mice were preconditioned with either 0.1 mL low-dose LPS (0.2 mg/kg) or phosphate-buffered saline (PBS) (control) followed by treatment with three consecutive injections of anti-HMGB1, IgY (an nonspecific antibody), or PBS, at 2, 12, and 22 h, respectively, Mice were then subjected to 0.1 mL high-dose LPS (10 mg/kg) or PBS at 24 h. Serum and hepatic tissue samples were obtained 1 or 3 h after final treatments. Signaling mechanisms were further investigated in the serum and hepatic tissues of mice preconditioned with 0.1 mL HMGB1 (1 mg/kg), low-dose LPS (0.2 mg/kg), or PBS for 1 h, and then high-dose LPS treatment for 3 h.
The signaling mechanisms involved in low-dose LPS preconditioning required enhanced endogenous HMGB1 expression and secretion. Neutralizing endogenous HMGB1 with anti-HMGB1 antibodies following low-dose LPS preconditioning altered endotoxin tolerance by increasing serum tumor necrosis factor α, reducing hepatic interleukin-1R-associated kinase M expression, and partially restoring nuclear factor κB in vivo. The translocation from nucleus to cytoplasm of endogenous HMGB1 in RAW264.7 cells was also observed during low-dose LPS-induced endotoxin tolerance.
Increased interleukin-1R-associated kinase M and decreased nuclear factor κB activity in endotoxin tolerance is associated with endogenous HMGB1 expression after low-dose LPS preconditioning. These findings provide a basis for a better mechanistic understanding and the development of safer clinical therapeutics utilizing induced endotoxin tolerance.
高迁移率族蛋白 B1（HMGB1）是脓毒症和内毒素血症中下游炎症反应调节剂，通过影响细胞低反应性和肿瘤坏死因子α及白细胞介素 1 的产生，改变内毒素耐受。
研究低剂量脂多糖（LPS）诱导内毒素耐受过程中内源性 HMGB1 信号转导机制。
BALB/c 小鼠分别用 0.1mL 低剂量 LPS（0.2mg/kg）或磷酸盐缓冲盐水（PBS）（对照组）预处理，然后在 2、12 和 22h 分别用 3 次抗 HMGB1、IgY（非特异性抗体）或 PBS 处理。24h 时，再次用 0.1mL 高剂量 LPS（10mg/kg）或 PBS 处理。末次处理后 1 或 3h 时，采集血清和肝组织样本。在经 0.1mL HMGB1（1mg/kg）、低剂量 LPS（0.2mg/kg）或 PBS 预处理 1h 后，再用高剂量 LPS 处理 3h，进一步研究小鼠血清和肝组织中的信号转导机制。
低剂量 LPS 预处理所涉及的信号转导机制需要增强内源性 HMGB1 的表达和分泌。低剂量 LPS 预处理后用抗 HMGB1 抗体中和内源性 HMGB1，增加了血清肿瘤坏死因子α，减少了肝组织白细胞介素-1 受体相关激酶 M 的表达，并部分恢复了体内核因子 κB。在低剂量 LPS 诱导的内毒素耐受过程中，还观察到 RAW264.7 细胞内源性 HMGB1 从核转位到细胞质。
低剂量 LPS 预处理后内源性 HMGB1 的表达与内毒素耐受中的白细胞介素-1 受体相关激酶 M 增加和核因子 κB 活性降低有关。这些发现为更好地理解其机制和利用诱导内毒素耐受开发更安全的临床治疗方法提供了依据。
