@article {64784,
	title = {An actin-based protrusion originating from a podosome-enriched region initiates macrophage fusion.},
	journal = {Molecular Biology of the Cell},
	volume = {30},
	year = {2019},
	month = {2019 Aug 1},
	pages = {2254-67},
	abstract = {<p>Macrophage fusion resulting in the formation of multinucleated giant cells occurs in a variety of chronic inflammatory diseases, yet the mechanism responsible for initiating macrophage fusion is unknown. Here, we used live cell imaging to show that actin-based protrusions at the leading edge initiate macrophage fusion. Phase contrast video microscopy demonstrated that in the majority of events, short protrusions (3 {\textpm} 1 μm) between two closely apposed cells initiated fusion, but occasionally we observed long protrusions (16 {\textpm} 7 μm). Using macrophages isolated from LifeAct mice and imaging with lattice light sheet microscopy, we further found that fusion-competent actin-based protrusions formed at sites enriched in podosomes. Inducing fusion in mixed populations of GFP- and mRFP-LifeAct macrophages showed rapid spatial overlap between GFP and RFP signal at the site of fusion. Cytochalasin B strongly reduced fusion and when rare fusion events occurred, protrusions were not observed. Fusion of macrophages deficient in Wiskott-Aldrich syndrome protein and Cdc42, key molecules involved in the formation of actin-based protrusions and podosomes, was also impaired both in vitro and in vivo. Finally, inhibiting the activity of the Arp2/3 complex decreased fusion and podosome formation. Together these data indicate that an actin-based protrusion formed at the leading edge macrophage fusion.</p>
},
	doi = {10.1101/538314},
	author = {Faust, James J and Balabiyev, Arnat and Heddleston, John M and Podolnikova, Nataly P and Baluch, Debra Page and Chew, Teng-Leong and Ugarova, Tatiana P}
}
@article {49129,
	title = {Fabricating optical-quality glass surfaces to study macrophage fusion.},
	journal = {Journal of Visualized Experiments : JoVE},
	year = {2018},
	month = {2018 Mar 14},
	abstract = {<p>Visualizing the formation of multinucleated giant cells (MGCs) from living specimens has been challenging due to the fact that most live imaging techniques require propagation of light through glass, but on glass macrophage fusion is a rare event. This protocol presents the fabrication of several optical-quality glass surfaces where adsorption of compounds containing long-chain hydrocarbons transforms glass into a fusogenic surface. First, preparation of clean glass surfaces as starting material for surface modification is described. Second, a method is provided for the adsorption of compounds containing long-chain hydrocarbons to convert non-fusogenic glass into a fusogenic substrate. Third, this protocol describes fabrication of surface micropatterns that promote a high degree of spatiotemporal control over MGC formation. Finally, fabricating glass bottom dishes is described. Examples of use of this in vitro cell system as a model to study macrophage fusion and MGC formation are shown.</p>
},
	issn = {1940-087X},
	doi = {10.3791/56866},
	author = {Faust, James J and Christenson, Wayne and Doudrick, Kyle and Heddleston, John and Chew, Teng-Leong and Lampe, Marko and Balabiyev, Arnat and Ros, Robert and Ugarova, Tatiana P}
}
