辅助性大麻素受体 2 激动剂调节实验性肺炎球菌性脑膜炎中小胶质细胞向非炎症表型的极化。

BACKGROUND: Microglia initiates and sustains the inflammatory reaction that drives the pathogenesis of pneumococcal meningitis. The expression of the G-protein cannabinoid receptor type 2 (CB2) in the brain is low, but is upregulated in glial cells during infection. Its activation down-regulates pro-inflammatory processes, driving microglia towards an anti-inflammatory phenotype. CB2 agonists are therefore therapeutic candidates in inflammatory conditions like pneumococcal meningitis. We evaluated the effects of JWH-133, a specific CB2 agonist on microglial cells, inflammation, and damage driven by and in experimental pneumococcal meningitis. MATERIALS/METHODS: Primary mixed glial cultures were stimulated with live or heat-inactivated , or lipopolysaccharide and treated with JWH-133 or vehicle. Nitric oxide and cytokines levels were measured in the supernatant. , pneumococcal meningitis was induced by intracisternal injection of live in 11 days old Wistar rats. Animals were treated with antibiotics (Ceftriaxone, 100 mg/kg, s.c. bid) and JWH-133 (1 mg/kg, i.p. daily) or vehicle (10% Ethanol in saline, 100 µl/25g body weight) at 18 h after infection. Brains were harvested at 24 and 42 h post infection (hpi) for histological assessment of hippocampal apoptosis and cortical damage and determination of cyto/chemokines in tissue homogenates. Microglia were characterized using Iba-1 immunostaining. Inflammation in brain homogenates was determined using membrane-based antibody arrays. RESULTS: , nitric oxide and cytokines levels were significantly lowered by JWH-133 treatment. , clinical parameters were not affected by the treatment. JWH-133 significantly lowered microglia activation assessed by quantification of cell process length and endpoints per microglia. Animals treated with JWH-133 demonstrated significantly lower parenchymal levels of chemokines (CINC-1, CINC-2α/β, and MIP-3α), TIMP-1, and IL-6 at 24 hpi, and CINC-1, MIP-1α, and IL-1α at 42 hpi. Quantitative analysis of brain damage did not reveal an effect of JWH-133. CONCLUSIONS: JWH-133 attenuates microglial activation and downregulates the concentrations of pro-inflammatory mediators in pneumococcal infection and . However, we didn't observe a reduction in cortical or hippocampal injury. This data provides evidence that inhibition of microglia by adjuvant CB2 agonists therapy effectively downmodulates neuroinflammation but does not reduce brain damage in experimental pneumococcal meningitis.

背景：小胶质细胞启动并维持了导致肺炎球菌性脑膜炎发病机制的炎症反应。大脑中的 G 蛋白大麻素受体 2（CB2）表达水平较低，但在感染期间胶质细胞中上调。其激活可下调促炎过程，使小胶质细胞向抗炎表型转化。因此，CB2 激动剂是肺炎球菌性脑膜炎等炎症性疾病的治疗候选药物。我们评估了特异性 CB2 激动剂 JWH-133 对实验性肺炎球菌性脑膜炎中和诱导的小胶质细胞炎症和损伤的影响。

材料/方法：用活的或热灭活的或脂多糖刺激原代混合神经胶质细胞，并使用 JWH-133 或载体处理。测量上清液中的一氧化氮和细胞因子水平。通过向 11 天大的 Wistar 大鼠的侧脑室内注射活诱导肺炎球菌性脑膜炎。感染后 18 小时，动物用抗生素（头孢曲松，100mg/kg，皮下注射，每日 2 次）和 JWH-133（1mg/kg，腹腔注射，每日 1 次）或载体（10%乙醇生理盐水，100µl/25g 体重）治疗。感染后 24 和 42 小时（hpi）收获大脑，用于海马凋亡和皮质损伤的组织学评估，并测定组织匀浆中的细胞因子/趋化因子。使用 Iba-1 免疫染色鉴定小胶质细胞。使用基于膜的抗体阵列测定脑匀浆中的炎症。

结果：用 JWH-133 处理可显著降低和的一氧化氮和细胞因子水平。JWH-133 处理并未影响临床参数。用 JWH-133 处理可显著降低小胶质细胞激活，这通过量化细胞过程长度和每个小胶质细胞的终点来评估。用 JWH-133 治疗的动物在 24 hpi 时脑实质中的趋化因子（CINC-1、CINC-2α/β 和 MIP-3α）、TIMP-1 和 IL-6 水平以及在 42 hpi 时 CINC-1、MIP-1α 和 IL-1α 水平显著降低。JWH-133 定量分析未显示对皮质或海马损伤有影响。

结论：JWH-133 可减轻和感染中小胶质细胞的激活，并下调促炎介质的浓度。然而，我们没有观察到皮质或海马损伤的减少。该数据表明，辅助 CB2 激动剂治疗抑制小胶质细胞可有效下调神经炎症，但不能减轻实验性肺炎球菌性脑膜炎中的脑损伤。