Immunochemistry Laboratory, Instituto Butantan, São Paulo, Brazil.
Farmabrasilis, Campinas, Brazil.
Mediators Inflamm. 2020 Nov 24;2020:8831389. doi: 10.1155/2020/8831389. eCollection 2020.
P-MAPA is a complex compound, derived from cultures, that has shown immunomodulatory properties in infection and cancer animal models. Despite promising results in these models, the mechanisms of cellular activation by P-MAPA, suggested to be Toll-like receptor- (TLR-) dependent, and its effect on human immune cells, remain unclear. Using an model of human whole blood, the effects of P-MAPA on complement system activation, production of cytokines, and the expression of complement receptors (CD11b, C5aR, and C3aR), TLR2, TLR4, and the coreceptor CD14 were analyzed in neutrophils and monocytes. P-MAPA induced complement activation in human blood, detected by increased levels of C3a, C5a, and SC5b-9 in plasma. As a consequence, CD11b expression increased and C5aR decreased upon activation, while C3aR expression remained unchanged in leukocytes. TLR2 and TLR4 expressions were not modulated by P-MAPA treatment on neutrophils, but TLR4 expression was reduced in monocytes, while CD14 expression increased in both cell types. P-MAPA also induced the production of TNF-, IL-8, and IL-12 and oxidative burst, measured by peroxynitrite levels, in human leukocytes. Complement inhibition with compstatin showed that P-MAPA-induced complement activation drives modulation of C5aR, but not of CD11b, suggesting that P-MAPA acts through both complement-dependent and complement-independent mechanisms. Compstatin also significantly reduced the peroxynitrite generation. Altogether, our results show that P-MAPA induced proinflammatory response in human leukocytes, which is partially mediated by complement activation. Our data contribute to elucidate the complement-dependent and complement-independent mechanisms of P-MAPA, which ultimately result in immune cell activation and in its immunomodulatory properties in infection and cancer animal models.
P-MAPA 是一种从 培养物中提取的复杂化合物，在感染和癌症动物模型中显示出免疫调节特性。尽管在这些模型中取得了有希望的结果，但 P-MAPA 激活细胞的机制，据推测是 Toll 样受体-（TLR-）依赖性的，以及它对人类免疫细胞的影响仍不清楚。使用人类全血 模型，分析了 P-MAPA 对补体系统激活、细胞因子产生以及补体受体（CD11b、C5aR 和 C3aR）、TLR2、TLR4 和共受体 CD14 在中性粒细胞和单核细胞中的表达的影响。P-MAPA 在人类血液中诱导补体激活，通过血浆中 C3a、C5a 和 SC5b-9 水平的升高来检测。结果，白细胞中的 CD11b 表达增加，C5aR 减少，而 C3aR 表达在白细胞中保持不变。P-MAPA 处理对中性粒细胞中 TLR2 和 TLR4 的表达没有调节作用，但在单核细胞中 TLR4 的表达减少，而在两种细胞类型中 CD14 的表达增加。P-MAPA 还诱导 TNF-、IL-8 和 IL-12 的产生和活性氧爆发，通过过氧亚硝酸盐水平来测量。用 compstatin 抑制补体表明，P-MAPA 诱导的补体激活驱动 C5aR 的调节，但不驱动 CD11b 的调节，表明 P-MAPA 通过补体依赖和补体非依赖机制发挥作用。compstatin 也显著降低了过氧亚硝酸盐的产生。总之，我们的结果表明，P-MAPA 诱导了人类白细胞的促炎反应，这部分是通过补体激活介导的。我们的数据有助于阐明 P-MAPA 的补体依赖和补体非依赖机制，这些机制最终导致免疫细胞的激活及其在感染和癌症动物模型中的免疫调节特性。
