Department of Laboratory Medicine, Chinese PLA General Hospital, Beijing 100853, China; Nankai University School of Medicine, Nankai University, Tianjin 300071, China.
Department of Laboratory Medicine, Chinese PLA General Hospital, Beijing 100853, China.
Cytokine. 2021 Feb;138:155377. doi: 10.1016/j.cyto.2020.155377. Epub 2020 Dec 18.
Bloodstream infection (BSI) is usually accompanied with the changes of varieties of inflammation proteins. In our previous study, we identified that inter-α-trypsin inhibitor heavy chain H4 (ITIH4) was highly expressed in the infection arms than the normal control arm. However, the correlated verification and mechanism remain obscure. Escherichia coli infected mice model and clinical serum samples were used to validate the concentration of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), interleukin-10 (IL-10), as well as ITIH4, in ELISA method. Cytokines (IL-6, TNF-α, IL-10 and lipopolysaccharide (LPS)) were used to stimulate the HepG2 cell model to explore which cytokines influence the expression of ITIH4. JAK/STAT inhibitor was treated before IL-6 and LPS stimulation. Westernblot, as well as real-time PCR were performed to detect the expression of ITIH4 in liver tissue from protein and transcription levels. Immunohistochemistry analysis was used to observe the expression of ITIH4 in mice liver tissue. In mice model, IL-6, TNF-α, as well as IL-10 increased in the infection arms than the normal control arm. ITIH4 in serum and liver tissue of mice model increased from 1 h to 128 h, which were remarkably different from that of the normal control arm. Besides, ITIH4 increased in the bacterial infection arm greatly than the fungemia arm, mycoplasma pneumoniae (MP) arm and febrile arm in clinical serum samples. Furthermore, using the HepG2 cell line, we demonstrated that ITIH4 was up-regulated at both protein and mRNA levels upon dose- and time- response treatments with IL-6, as well as LPS. Moreover, IL-6 or LPS mediated induction of ITIH4 expression could be significantly decreased by treatment with an JAK/STAT inhibitor in protein or mRNA level. No changes were observed after TNF-α or IL-10 stimulation. ITIH4 might be a critical inflammatory biomarker which correlated with the development of BSI, especially with bacterial bloodstream infection. It is expected that this study would provide some insights into potential functional mechanisms underlying BSI.
血流感染（BSI）通常伴随着炎症蛋白种类的变化。在我们之前的研究中，我们发现α-胰蛋白酶抑制剂重链 H4（ITIH4）在感染组中的表达明显高于正常对照组。然而，相关的验证和机制仍不清楚。本研究采用大肠杆菌感染小鼠模型和临床血清样本，通过 ELISA 法验证白细胞介素 6（IL-6）、肿瘤坏死因子-α（TNF-α）、白细胞介素 10（IL-10）和 ITIH4 的浓度。用细胞因子（IL-6、TNF-α、IL-10 和脂多糖（LPS））刺激 HepG2 细胞模型，探讨哪些细胞因子影响 ITIH4 的表达。在 IL-6 和 LPS 刺激前用 JAK/STAT 抑制剂处理。采用 Western blot 和实时 PCR 检测肝组织中 ITIH4 的表达，从蛋白和转录水平进行检测。采用免疫组化分析观察 ITIH4 在小鼠肝组织中的表达。在小鼠模型中，感染组的 IL-6、TNF-α和 IL-10 均高于正常对照组。从 1 小时到 128 小时，小鼠模型血清和肝组织中的 ITIH4 增加，与正常对照组有显著差异。此外，在临床血清样本中，细菌感染组的 ITIH4 明显高于真菌血症组、肺炎支原体（MP）组和发热组。此外，我们通过 HepG2 细胞系证明，IL-6 和 LPS 剂量和时间反应处理均可使 ITIH4 在蛋白和 mRNA 水平上调。此外，用 JAK/STAT 抑制剂处理可显著降低 IL-6 或 LPS 介导的 ITIH4 表达诱导，而 TNF-α 或 IL-10 刺激后无变化。ITIH4 可能是与 BSI 尤其是细菌性血流感染发展相关的关键炎症生物标志物。本研究有望为 BSI 的潜在功能机制提供一些见解。
