Dept. Immunology, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, RJ, Brazil.
Dept. Pediatrics, Instituto Nacional de Saúde da Mulher, da Criança e do Adolescente Fernandes Figueira, FIOCRUZ, RJ, Brazil.
Int Immunopharmacol. 2017 Apr;45:79-89. doi: 10.1016/j.intimp.2017.02.001. Epub 2017 Feb 10.
Despite the close relationship of eosinophils and neutrophils, these granulocyte lineages respond to distinct cytokines and play unique roles in immune responses. They nevertheless respond to shared physiological/pharmacological regulators, including glucocorticoids and retinoids, and to ubiquitous mediators, including NO. Others showed that, in humans, all-trans retinoic acid (ATRA) suppresses eosinophil differentiation, but promotes neutrophil differentiation. Mechanisms of dual co-regulation of physiological granulopoiesis were here examined in murine bone-marrow, a model system suitable for exploration of immunopharmacological mechanisms, given the availability of experimental resources, including mutant/knockout mouse strains. We examined the effects of ATRA on mouse eosinophil and neutrophil production, using wild-type (BALB/c, C57BL/6) and mutant (iNOS-, CD95L-, or CD95-KO) bone-marrow cultures, further assessing the modification of ATRA activity by dexamethasone and iNOS blockade. ATRA (10-10M) significantly decreased eosinophil production relative to IL-5 controls. This effect was iNOS-independent, but CD95L- and caspase-dependent, and prevented by dexamethasone (10M in vitro; 1-20mg·kg in vivo). In myeloid colony formation assays, ATRA markedly suppressed GM-CSF-responsive progenitors, through an iNOS-dependent, CD95-independent, dexamethasone-sensitive mechanism. By contrast, ATRA potently enhanced GM-CSF-dependent neutropoiesis in liquid culture from BALB/c or C57BL/6 bone-marrow. This novel stimulatory effect was resistant to dexamethasone and abolished in iNOS-KO bone-marrow. ATRA injections also induced lineage- and stage-selective effects on granulopoiesis in vivo. ATRA therefore co-regulates eosinophil and neutrophil production in murine bone-marrow through multiple lineage- and stage-selective mechanisms.
尽管嗜酸性粒细胞和中性粒细胞密切相关，但这两种粒细胞谱系对不同的细胞因子作出反应，并在免疫反应中发挥独特的作用。然而，它们对共同的生理/药理学调节剂（包括糖皮质激素和类视黄醇）以及普遍存在的介质（包括 NO）作出反应。其他人表明，在人类中，全反式视黄酸（ATRA）抑制嗜酸性粒细胞分化，但促进中性粒细胞分化。在此，我们研究了生理粒细胞生成的双重共同调节机制，在该模型系统中，由于实验资源的可用性，包括突变/敲除小鼠品系，因此适合探索免疫药理学机制。我们使用野生型（BALB/c、C57BL/6）和突变型（iNOS-、CD95L-或 CD95-KO）骨髓培养物研究了 ATRA 对小鼠嗜酸性粒细胞和中性粒细胞产生的影响，进一步评估了地塞米松和 iNOS 阻断对 ATRA 活性的修饰。ATRA（10-10M）与 IL-5 对照相比，显著降低了嗜酸性粒细胞的产生。这种作用与 iNOS 无关，但与 CD95L 和半胱天冬酶依赖性有关，并被地塞米松（体外 10M；体内 1-20mg·kg）所预防。在髓样集落形成测定中，ATRA 通过一种 iNOS 依赖性、CD95 独立性、地塞米松敏感性机制显著抑制 GM-CSF 反应性祖细胞。相比之下，ATRA 强力增强 BALB/c 或 C57BL/6 骨髓的 GM-CSF 依赖性中性粒细胞生成。这种新的刺激作用对地塞米松有抗性，并在 iNOS-KO 骨髓中被消除。ATRA 注射还在体内诱导粒细胞生成的谱系和阶段选择性效应。因此，ATRA 通过多种谱系和阶段选择性机制共同调节小鼠骨髓中的嗜酸性粒细胞和中性粒细胞产生。
