Institute of Inflammation, Infection and Immunity, Gastrointestinal Research Group, Department of Physiology and Pharmacology, University of Calgary, Alberta, Canada.
J Leukoc Biol. 2011 Jun;89(6):945-53. doi: 10.1189/jlb.0809546. Epub 2011 Mar 10.
GM-CSF is well recognized as a proliferative agent for hematopoietic cells and exerts a priming function on neutrophils. The aim of this study was to determine if GM-CSF has a role as a neutrophil chemoattractant in vivo and if it can contribute to recruitment during intestinal inflammation. Initial studies in vitro, using the under-agarose gel assay, determined that GM-CSF can induce neutrophil migration at a much lower molar concentration than the fMLP-like peptide WKYMVm (33.5-134 nM vs. 1-10 μM). GM-CSF-induced neutrophil migration was ablated (<95%) using neutrophils derived from GMCSFRβ(-/-) mice and significantly attenuated by 42% in PI3Kγ(-/-)neutrophils. In vivo, a significant increase in leukocyte recruitment was observed using intravital microscopy 4 h post-GM-CSF (10 μg/kg) injection, which was comparable with leukocyte recruitment induced by KC (40 μg/kg). GM-CSF-induced recruitment was abolished, and KC-induced recruitment was maintained in GMCSFRβ(-/-) mice. Furthermore, in vivo migration of extravascular leukocytes was observed toward a gel containing GM-CSF in WT but not GMCSFRβ(-/-) mice. Finally, in a model of intestinal inflammation (TNBS-induced colitis), colonic neutrophil recruitment, assessed using the MPO assay, was attenuated significantly in anti-GM-CSF-treated mice or GMCSFRβ(-/-) mice. These data demonstrate that GM-CSF is a potent chemoattractant in vitro and can recruit neutrophils from the microvasculature and induce extravascular migration in vivo in a β subunit-dependent manner. This property of GM-CSF may contribute significantly to recruitment during intestinal inflammation.
GM-CSF 被公认为造血细胞的增殖剂，并对中性粒细胞发挥启动作用。本研究旨在确定 GM-CSF 是否在体内作为中性粒细胞趋化因子发挥作用，以及它是否可以在肠道炎症期间有助于招募。体外的初步研究使用琼脂糖凝胶测定法确定，GM-CSF 可以在比 fMLP 样肽 WKYMVm（33.5-134 nM 比 1-10 μM）低得多的摩尔浓度下诱导中性粒细胞迁移。GM-CSF 诱导的中性粒细胞迁移在 GMCSFRβ(-/-) 小鼠衍生的中性粒细胞中被消融（<95%），并且在 PI3Kγ(-/-)中性粒细胞中被显著衰减 42%。在体内，使用活体显微镜观察到 GM-CSF（10 μg/kg）注射后 4 小时白细胞募集显著增加，与 KC（40 μg/kg）诱导的白细胞募集相当。GM-CSF 诱导的募集被废除，而 KC 诱导的募集在 GMCSFRβ(-/-) 小鼠中得以维持。此外，在 WT 小鼠中观察到血管外白细胞向含有 GM-CSF 的凝胶中趋化的现象，但在 GMCSFRβ(-/-) 小鼠中则没有。最后，在肠道炎症模型（TNBS 诱导的结肠炎）中，使用 MPO 测定法评估的结肠中性粒细胞募集在抗 GM-CSF 处理的小鼠或 GMCSFRβ(-/-) 小鼠中显著减弱。这些数据表明 GM-CSF 是一种有效的体外趋化因子，可以从微血管募集中性粒细胞并以β亚基依赖性方式诱导体内血管外迁移。GM-CSF 的这种特性可能在肠道炎症期间的招募中具有重要意义。
