A method for long-term live imaging of tissue macrophages in adipose tissue explants
A method for long-term live imaging of tissue macrophages in adipose tissue explants
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DOI：
10.1152/ajpendo.00075.2015
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发表时间：
2015-06-01
影响因子：
5.1
通讯作者：
Eilers, Jens
中科院分区：
文献类型：
--
作者：
Gericke, Martin;Weyer, Ulrike;Eilers, Jens
肥胖通常与脂肪组织（AT）内的慢性低度炎症有关。虽然AT炎症中缺少经典的炎症体征，但巨噬细胞显著增加，其他免疫细胞如T细胞、B细胞、肥大细胞和嗜中性粒细胞也显著增加，但程度较轻。这些细胞的空间和时间激活以及它们在AT中的积累似乎与所谓的冠状结构（CLS）紧密相关。CLS是死亡脂肪细胞周围脂肪组织巨噬细胞（ATM）的积聚，被认为反映了清道夫反应。目前，关于CLS生命周期的数据缺失。为了更好地了解AT炎症的细胞事件，我们开发了一种方法，允许在活AT外植体内对ATM、脂肪细胞和CLS进行长期成像。我们测试了三个假定的报告小鼠骨髓细胞系在其适用性的活成像。因此，我们鉴定了来自CSF 1 R-eGFP小鼠的ATM，以显示最稳健的eGFP表达。来自这些小鼠的AT外植体允许稳定的活体成像超过7天，而没有显著的光毒性。因此，长期成像显示死亡的脂肪细胞周围的ATM的积累，AT内的ATM的迁移，以及死亡的脂肪细胞的脂质残留物的降解。在AT炎症的背景下观察到的ATM行为与以前的研究一致，但首次提供了关于单个ATM的特定行为和CLS生命周期的数据，具有前所未有的时空分辨率。
Obesity is frequently associated with a chronic low-grade inflammation within adipose tissue (AT). Although classical signs of inflammation are missing in AT inflammation, there is a significant increase in macrophages and, to a lesser extent, other immune cells, such as T cells, B cells, mast cells, and neutrophils. The spatial and temporal activation of these cells as well as their accumulation in the AT seem to be tightly linked to so-called crown-like structures (CLS). CLS are accumulations of adipose tissue macrophages (ATMs) around dead adipocytes and are thought to reflect a scavenger response. At present, data on the life cycle of CLS are missing. To better understand the cellular events underlying AT inflammation, we developed an approach that allows long-term imaging of ATMs, adipocytes, and CLS within live AT explants. We tested three putative reporter mouse lines for myeloid cells in regard to their suitability for live imaging. Thereby, we identified ATMs from CSF1R-eGFP mice to exhibit the most robust expression of eGFP. AT explants from these mice allowed stable live imaging for more than 7 days without significant phototoxicity. Long-term imaging thus revealed the accumulation of ATMs around dying adipocytes, migration of ATMs within AT, and also the degradation of the lipid remnants of perishing adipocytes. The observed behavior of ATMs in the context of AT inflammation is in line with previous studies but for the first time provides data on the specific behavior of individual ATMs and on the life cycle of CLS with unprecedented spatiotemporal resolution.