Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, 14040-903, Brazil.
Departamento de Bioquímica e Imunologia, Faculdade de Medicina de Ribeirão Preto, Ribeirão Preto, 14049-900, Brazil.
Inflamm Res. 2022 Dec;71(12):1535-1546. doi: 10.1007/s00011-022-01641-8. Epub 2022 Oct 25.
Our research aimed to investigate the role of CD14 in pulmonary infection by Achromobacter xylosoxidans in an experimental murine model.
C57Bl/6 or CD14-deficient mice were infected intratracheally with non-lethal inoculum of A. xylosoxidans. At times 1, 3 and 7 days after infection, lungs, bronchoalveolar lavage and blood were collected. CD14 gene expression was determined by RT-PCR. The bacterial load in the lungs was assessed by counting colony forming units (CFU). Cytokines, chemokines, lipocalin-2 and sCD14 were quantified by the ELISA method. Inflammatory infiltrate was observed on histological sections stained with HE, and leukocyte subtypes were assessed by flow cytometry. In another set of experiments, C57Bl/6 or CD14-deficient mice were inoculated with lethal inoculum and the survival rate determined.
CD14-deficient mice are protected from A. xylosoxidans-induced death, which is unrelated to bacterial load. The lungs of CD14-deficient mice presented a smaller area of tissue damage, less neutrophil and macrophage infiltration, less pulmonary edema, and a lower concentration of IL-6, TNF-α, CXCL1, CCL2 and CCL3 when compared with lungs of C57Bl/6 mice. We also observed that A. xylosoxidans infection increases the number of leukocytes expressing mCD14 and the levels of sCD14 in BALF and serum of C57Bl/6-infected mice.
In summary, our data show that in A. xylosoxidans infection, the activation of CD14 induces intense pulmonary inflammatory response resulting in mice death.
我们的研究旨在探讨 CD14 在实验性小鼠气单胞菌肺部感染中的作用。
C57Bl/6 或 CD14 缺陷小鼠经气管内感染低致死量气单胞菌。感染后 1、3 和 7 天，收集肺、支气管肺泡灌洗液和血液。采用 RT-PCR 检测 CD14 基因表达。通过菌落形成单位（CFU）计数评估肺部细菌负荷。采用 ELISA 法检测细胞因子、趋化因子、脂钙蛋白-2 和 sCD14。用 HE 染色的组织切片观察炎症浸润，用流式细胞术评估白细胞亚型。在另一组实验中，用致死量接种 C57Bl/6 或 CD14 缺陷小鼠，测定存活率。
CD14 缺陷小鼠免受气单胞菌诱导的死亡保护，与细菌负荷无关。与 C57Bl/6 小鼠相比，CD14 缺陷小鼠的肺部组织损伤面积较小，中性粒细胞和巨噬细胞浸润较少，肺水肿较轻，IL-6、TNF-α、CXCL1、CCL2 和 CCL3 浓度较低。我们还观察到，气单胞菌感染增加了表达 mCD14 的白细胞数量和 BALF 及血清中 sCD14 的水平。
综上所述，我们的数据表明，在气单胞菌感染中，CD14 的激活诱导强烈的肺部炎症反应，导致小鼠死亡。
