Jiangsu Province Key Laboratory for Molecular and Medicine Biotechnology, College of Life Science, Nanjing Normal University, Nanjing, Jiangsu, PR China.
Jiangsu Province Key Laboratory for Molecular and Medicine Biotechnology, College of Life Science, Nanjing Normal University, Nanjing, Jiangsu, PR China; Collaborative Innovation Center of Biomedicine for Public Hygiene Emergency and Critical Care, Jiangsu Life Sciences & Technology Innovation Park, Nanjing, Jiangsu, PR China.
PLoS One. 2014 Mar 6;9(3):e89634. doi: 10.1371/journal.pone.0089634. eCollection 2014.
High mobility group box 1(HMGB1) was first recognized as a nuclear protein that increased the chromatin remodeling and regulates transcription of many genes. In recent years, HMGB1 has been identified as a critical "late" pro-inflammatory mediator due to its unique secretion pattern and lethal effects in sepsis. Therefore, preventing the active release and inhibiting the pro-inflammatory activity of HMGB1 become promising strategies for the treatment of sepsis. Here, we reported the therapeutic effects of Gu-4, a lactosyl derivative, on sepsis and the underlying molecular mechanisms.
METHODOLOGY/PRINCIPAL FINDINGS: In an experimental rat model of sepsis caused by cecal ligation and puncture (CLP), Gu-4 administration prominently attenuated lung injury and improved the survival of the septic animals, which was positively correlated with the decrease of the serum HMGB1 level. Using RAW264.7 macrophage cell line, we further showed that Gu-4 significantly suppressed the lipopolysaccharide (LPS)-induced release and cytoplasmic translocation of HMGB1. Moreover, Gu-4 not only dose-dependently attenuated recombinant human (rhHMGB1)-induced production of TNF-α, IL-6, and IL-1β in THP-1 cells, but also greatly inhibited the adhesion of rhHMGB1-challenged THP-1 cells to HUVECs. Analyses of flow cytometry demonstrated that Gu-4 could effectively reduce the activation of CD11b elicited by rhHMGB1. Western blot analyses revealed that Gu-4 treatment could partially block the rhHMGB1-induced activation of ERK and NF-κB signalings. Meanwhile, CD11b knockdown also obviously attenuated the rhHMGB1-induced phosphorylations of ERK and IKKα/β.
CONCLUSIONS/SIGNIFICANCE: Taken together, our results suggest that Gu-4 possesses a therapeutic potential in the treatment of sepsis probably via inhibiting the LPS-induced release of HMGB1 from macrophages and via suppressing the pro-inflammatory activity of HMGB1.
高迁移率族蛋白 B1（HMGB1）最初被认为是一种核蛋白，可增加染色质重塑并调节许多基因的转录。近年来，由于其独特的分泌模式和在败血症中的致死作用，HMGB1 已被鉴定为一种关键的“晚期”促炎介质。因此，防止 HMGB1 的主动释放并抑制其促炎活性成为治疗败血症的有前途的策略。在这里，我们报告了乳糖基衍生物 Gu-4 对败血症的治疗作用及其潜在的分子机制。
方法/主要发现：在盲肠结扎和穿孔（CLP）引起的败血症实验大鼠模型中，Gu-4 给药可明显减轻肺损伤并改善败血症动物的存活率，这与血清 HMGB1 水平的降低呈正相关。使用 RAW264.7 巨噬细胞系，我们进一步表明 Gu-4 可显著抑制脂多糖（LPS）诱导的 HMGB1 释放和细胞质易位。此外，Gu-4 不仅剂量依赖性地减弱了重组人（rhHMGB1）诱导的 THP-1 细胞中 TNF-α、IL-6 和 IL-1β的产生，而且还大大抑制了 rhHMGB1 挑战的 THP-1 细胞与 HUVECs 的粘附。流式细胞术分析表明，Gu-4 可以有效地减少 rhHMGB1 引起的 CD11b 的激活。Western blot 分析表明，Gu-4 处理可以部分阻断 rhHMGB1 诱导的 ERK 和 NF-κB 信号转导的激活。同时，CD11b 敲低也明显减弱了 rhHMGB1 诱导的 ERK 和 IKKα/β的磷酸化。
结论/意义：综上所述，我们的结果表明，Gu-4 通过抑制巨噬细胞中 LPS 诱导的 HMGB1 释放和抑制 HMGB1 的促炎活性，具有治疗败血症的潜力。
