Sorokin S P, Hoyt R F, McNelly N A
Department of Anatomy and Neurobiology, Boston, University School of Medicine, MA 02118-2394, USA.
Anat Rec. 1996 Dec;246(4):481-97. doi: 10.1002/(SICI)1097-0185(199612)246:4<481::AID-AR8>3.0.CO;2-Y.
When fetal rat lungs are explanted to organ culture, precursor angular cells soon convert to nascent macrophages that multiply rapidly as they mature into efficient phagocytes. The present study examines the influence of proinflammatory early cytokines of the tumor necrosis factor-alpha (TNF alpha) cascade on this initial expression of the macrophage phenotype.
Fourteen- and 15-day fetal rat lungs were grown for varying periods on an agar-solidified medium with and without test factors added singly or in combination. Growth of the macrophage population was followed daily by light microscopy and quantified by measuring the area of coronas formed as cells emerged from explants.
TNF alpha interleukin-1 beta (IL-1 beta) stimulated growth of the macrophage population, as had macrophage- and granulocyte-macrophage colony-stimulating factors (M- and GM-CSFs) in prior studies. Inhibition was obtained by exposure to IL-1 receptor antagonist and antibodies neutralizing the CSFs. Only the effects of TNF alpha were sufficiently delayed to discount possible influence on conversion and growth of nascent macrophages. Two transcription blockers, dexamethasone and pyrrolidine dithiocarbamate (PDTC), an inhibitor of nuclear factor NF-kappa B, both profoundly suppressed macrophage growth without preventing conversion of precursors. Effects of dexamethasone were significantly ameliorated by IL-1 beta alone and combined with GM-CSF; those of PDTC were mitigated by M-CSF and a combination of IL-1 beta and TNF alpha but not by GM-CSF.
IL-1 beta, M-CSF, and GM-CSF all promote growth of the young macrophage population. TNF alpha is effective only later on, likely because early-stage cells lack its receptors which normally use intracellular signalling pathways similar to those for IL-1. The severity of PDTC inhibition to population growth indicates that NF-kappa B is important for transmitting proliferative signals in these cells.
当将胎鼠肺组织移植到器官培养体系中时，前体细胞很快会转变为新生巨噬细胞，这些巨噬细胞在成熟为高效吞噬细胞的过程中迅速增殖。本研究探讨肿瘤坏死因子-α（TNFα）级联反应中的促炎早期细胞因子对巨噬细胞表型初始表达的影响。
将14日龄和15日龄的胎鼠肺组织在添加或不添加单一或联合测试因子的琼脂固化培养基上培养不同时间。每天通过光学显微镜观察巨噬细胞群体的生长情况，并通过测量细胞从外植体中长出时形成的晕圈面积进行定量分析。
TNFα和白细胞介素-1β（IL-1β）刺激了巨噬细胞群体的生长，这与先前研究中巨噬细胞集落刺激因子（M-CSF）和粒细胞-巨噬细胞集落刺激因子（GM-CSF）的作用相同。通过暴露于IL-1受体拮抗剂和中和CSF的抗体可获得抑制效果。只有TNFα的作用被充分延迟，从而排除了对新生巨噬细胞转化和生长的可能影响。两种转录阻滞剂，地塞米松和核因子NF-κB的抑制剂吡咯烷二硫代氨基甲酸盐（PDTC），都能显著抑制巨噬细胞生长，但不阻止前体细胞的转化。单独使用IL-1β以及与GM-CSF联合使用可显著改善地塞米松的作用；PDTC的作用可被M-CSF以及IL-1β和TNFα的联合使用减轻，但不能被GM-CSF减轻。
IL-1β、M-CSF和GM-CSF均促进年轻巨噬细胞群体的生长。TNFα仅在后期有效，可能是因为早期细胞缺乏其受体，而这些受体通常使用与IL-1类似的细胞内信号通路。PDTC对群体生长的抑制程度表明NF-κB在这些细胞中传递增殖信号方面很重要。
