TRANSITION OF PODOSOMES INTO ZIPPER-LIKE STRUCTURES IN MACROPHAGE-DERIVED MULTINUCLEATED GIANT CELLS

ABSTRACTMacrophage fusion resulting in the formation of multinucleated giant cells (MGCs) is a multistage process that requires many adhesion-dependent steps and involves the rearrangement of the actin cytoskeleton. The diversity of actin-based structures and their role in macrophage fusion is poorly understood. In this study, we revealed hitherto unrecognized actin-based zipper-like structures (ZLSs) that arise between MGCs formed on the surface of implanted biomaterials. We established an in vitro model for the induction of these structures in mouse macrophages undergoing IL-4– mediated fusion. Using this model, we show that over time MGCs develop cell-cell contacts containing ZLSs. Live-cell imaging using macrophages isolated from mRFP- or GFP-Lifeact mice demonstrated that ZLSs are dynamic formations undergoing continuous assembly and disassembly and that podosomes are precursors of these structures. Immunostaining experiments showed that vinculin, talin, integrin αMβ2, and other components of podosomes are present in ZLSs. Macrophages deficient in WASp or Cdc42, two key molecules involved in actin core organization in podosomes, as well as cells treated with the inhibitors of the Arp2/3 complex failed to form ZLSs. Furthermore, E-cadherin and nectin-2 were found between adjoining membranes, suggesting that the transition of podosomes into ZLSs is induced by bridging plasma membranes by junctional proteins.

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Transition of podosomes into zipper-like structures in macrophage-derived multinucleated giant cells

Molecular Biology of the Cell ◽

10.1091/mbc.e19-12-0707 ◽

2020 ◽

Vol 31 (18) ◽

pp. 2002-2020

Author(s):

Arnat Balabiyev ◽

Nataly P. Podolnikova ◽

Aibek Mursalimov ◽

David Lowry ◽

Jason M. Newbern ◽

...

Keyword(s):

Plasma Membranes ◽

Giant Cells ◽

Multinucleated Giant Cells ◽

E Cadherin

Our study reveals previously unrecognized actin-based zipper-like structures (ZLSs) formed between macrophage-derived multinucleated giant cells undergoing fusion in vivo and in vitro. It is shown that podosomes are precursors of these structures. The transition of podosomes into ZLSs is induced by bridging plasma membranes by E-cadherin and nectin-2.

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TRANSFORMATION OF MONOCYTES IN TISSUE CULTURE INTO MACROPHAGES, EPITHELIOID CELLS, AND MULTINUCLEATED GIANT CELLS

The Journal of Cell Biology ◽

10.1083/jcb.28.2.303 ◽

1966 ◽

Vol 28 (2) ◽

pp. 303-332 ◽

Cited By ~ 306

Author(s):

Jerry S. Sutton ◽

Leon Weiss

Keyword(s):

Golgi Apparatus ◽

Plasma Membranes ◽

Giant Cells ◽

Progressive Increase ◽

Multinucleated Giant Cells ◽

Epithelioid Cells ◽

Cytoplasmic Filaments ◽

Monocytes And Macrophages ◽

Sequential Transformation

The sequential transformation of chicken monocytes into macrophages, epithelioid cells, and multinucleated giant cells in vitro was studied by electron microscopy after fixation and embedment in situ. The following changes occur. In the nucleus, margination of chromatin, evident in monocytes, decreases in later forms. Nucleoli become more complex and nuclear pores increase in number. In cytoplasm, a progressive increase in volume of the ectoplasm and endoplasm occurs in culture. Lysosomes increase in number and size prior to phagocytosis. During phagocytosis (most active from 1 to 3 days of culture) lysosome depletion occurs. Lysosomes are present in greatest number and show maximal structural variation in the epithelioid and young giant cells. Aging giant cells lose lysosomes. All stages possess variably large quantities of rough-surfaced endoplasmic reticulum and free ribosomes. The Golgi apparatus, small in monocytes, increases in size and complexity. Massive accumulations of lysosomes within the Golgi apparatus of macrophages and epithelioid cells suggest that lysosomes originate there. In giant cells, multiple Golgi regions occur, often ringing the nuclei. Monocytes and macrophages have few mitochondria. Mitochondria of epithelioid cells are larger, more numerous, and may have discontinuous outer membranes. Mitochondria are most numerous in giant cells where they increase with age and become polymorphous. Cytoplasmic filaments are approximately 50 to 60 A in diameter and of indeterminate length. They occur both singly and in bundles which touch cytoplasmic vesicles and mitochondria. Few filaments occur in monocytes and macrophages. A large increase in the number of filaments occurs in epithelioid cells, where filaments (90 to 100 A) surround the cytocentrum as a distinctive annular bundle often branching into the cytoplasm. The greatest concentration of filaments occurs in aged giant cells. Pseudopodia are always present. They are short and filiform in monocytes and giant cells, and broad, with abundant micropinocytotic vesicles, in macrophages and epithelioid cells. At every stage, the cell membrane contains dense cuplike structures. These may represent the membranous residue of lysosomes which have discharged to the outside, analogous to merocrine secretion. Contiguous epithelioid cells display elaborate cytoplasmic interdigitation. In places, the plasma membranes break down and epithelioid cells fuse to form giant cells.

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A new visible-light-excitable ICT-CHEF-mediated fluorescence ‘turn-on’ probe for the selective detection of Cd2+ in a mixed aqueous system with live-cell imaging

Dalton Transactions ◽

10.1039/c4dt02463j ◽

2015 ◽

Vol 44 (12) ◽

pp. 5763-5770 ◽

Cited By ~ 58

Author(s):

Shyamaprosad Goswami ◽

Krishnendu Aich ◽

Sangita Das ◽

Chitrangada Das Mukhopadhyay ◽

Deblina Sarkar ◽

...

Keyword(s):

Visible Light ◽

Live Cell Imaging ◽

Cell Imaging ◽

Aqueous System ◽

Live Cell ◽

Selective Detection ◽

Turn On ◽

Fluorescence Turn On

A new quinoline based sensor was developed and applied for the selective detection of Cd2+ both in vitro and in vivo.

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tdLanYFP, a yellow, bright, photostable and pH insensitive fluorescent protein for live cell imaging and FRET-based sensing strategies

10.1101/2021.04.27.441613 ◽

2021 ◽

Author(s):

Y. Bousmah ◽

H. Valenta ◽

G. Bertolin ◽

U. Singh ◽

V. Nicolas ◽

...

Keyword(s):

Single Molecule ◽

Live Cell Imaging ◽

Cell Imaging ◽

Fluorescent Protein ◽

Fluorescent Proteins ◽

Yellow Fluorescent Protein ◽

Resonance Energy ◽

Live Cell ◽

Live Cells

AbstractYellow fluorescent proteins (YFP) are widely used as optical reporters in Förster Resonance Energy Transfer (FRET) based biosensors. Although great improvements have been done, the sensitivity of the biosensors is still limited by the low photostability and the poor fluorescence performances of YFPs at acidic pHs. In fact, today, there is no yellow variant derived from the EYFP with a pK1/2 below ∼5.5. Here, we characterize a new yellow fluorescent protein, tdLanYFP, derived from the tetrameric protein from the cephalochordate B. lanceolatum, LanYFP. With a quantum yield of 0.92 and an extinction coefficient of 133 000 mol−1.L.cm−1, it is, to our knowledge, the brightest dimeric fluorescent protein available, and brighter than most of the monomeric YFPs. Contrasting with EYFP and its derivatives, tdLanYFP has a very high photostability in vitro and preserves this property in live cells. As a consequence, tdLanYFP allows the imaging of cellular structures with sub-diffraction resolution with STED nanoscopy. We also demonstrate that the combination of high brightness and strong photostability is compatible with the use of spectro-microscopies in single molecule regimes. Its very low pK1/2 of 3.9 makes tdLanYFP an excellent tag even at acidic pHs. Finally, we show that tdLanYFP can be a FRET partner either as donor or acceptor in different biosensing modalities. Altogether, these assets make tdLanYFPa very attractive yellow fluorescent protein for long-term or single-molecule live-cell imaging that is also suitable for FRET experiment including at acidic pH.

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BMP4-induced symmetry breaking in a 3D model of the human epiblast

10.21203/rs.2.9730/v1 ◽

2019 ◽

Cited By ~ 1

Author(s):

Mijo Simunovic ◽

Ali H. Brivanlou ◽

Eric D. Siggia

Keyword(s):

Live Cell Imaging ◽

3D Model ◽

Epithelial To Mesenchymal Transition ◽

Cell Imaging ◽

Embryonic Stem ◽

Primitive Streak ◽

Mesenchymal Transition ◽

Pluripotency Markers ◽

Anterior Posterior

Abstract We describe the protocol of generating a 3D stem-cell-based model of the human pre-gastrulation epiblast by culturing human embryonic stem cells in a mix of hydrogel and Matrigel. Much like the epiblast of an in vitro attached day-10 human embryo, this model is an epithelial sphere with a cavity at its center, it is expressing key pluripotency markers, and it displays apico-basal polarity. The 3D colonies can further be differentiated with morphogens and in the case of intermediate concentrations of BMP4, they break the anterior-posterior symmetry characterized by an asymmetric expression of a primitive streak marker and showing signs of epithelial to mesenchymal transition. The protocol described here is suitable for immunofluorescence staining and for live-cell imaging.

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A small-molecule with a large two-photon absorption cross-section serves as a membrane-permeable ribonucleic acid (RNA) probe for live cell imaging

New Journal of Chemistry ◽

10.1039/c8nj02425a ◽

2018 ◽

Vol 42 (17) ◽

pp. 14325-14331 ◽

Cited By ~ 2

Author(s):

Ruiqing Feng ◽

Longlong Li ◽

Bing Li ◽

Jinhui Li ◽

Dan Peng ◽

...

Keyword(s):

Cross Section ◽

Cross Sections ◽

Live Cell Imaging ◽

Plasma Membranes ◽

Cell Imaging ◽

Photon Absorption ◽

Absorption Cross ◽

High Permeability ◽

Two Photon Absorption ◽

Two Photon

DMI could light up the RNA of the nucleus and the cytoplasm in living systems, which not only exhibits larger two-photon absorption cross-sections (981 GM), but also displays high-permeability to plasma membranes of vigorous cells.

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