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In Vivo Imaging and Quantitative Analysis of Leukocyte Directional Migration and Polarization in Inflamed Tissue
Directional migration of transmigrated leukocytes to the site of injury is a central event in the inflammatory response. Here, we present an in vivo chemotaxis assay enabling the visualization and quantitative analysis of subtype-specific directional motility and polarization of leukocytes in their...
Autores principales: | , , , , , |
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Formato: | Texto |
Lenguaje: | English |
Publicado: |
Public Library of Science
2009
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2649502/ https://www.ncbi.nlm.nih.gov/pubmed/19259262 http://dx.doi.org/10.1371/journal.pone.0004693 |
Sumario: | Directional migration of transmigrated leukocytes to the site of injury is a central event in the inflammatory response. Here, we present an in vivo chemotaxis assay enabling the visualization and quantitative analysis of subtype-specific directional motility and polarization of leukocytes in their natural 3D microenvironment. Our technique comprises the combination of i) semi-automated in situ microinjection of chemoattractants or bacteria as local chemotactic stimulus, ii) in vivo near-infrared reflected-light oblique transillumination (RLOT) microscopy for the visualization of leukocyte motility and morphology, and iii) in vivo fluorescence microscopy for the visualization of different leukocyte subpopulations or fluorescence-labeled bacteria. Leukocyte motility parameters are quantified off-line in digitized video sequences using computer-assisted single cell tracking. Here, we show that perivenular microinjection of chemoattractants [macrophage inflammatory protein-1α (MIP-1α/Ccl3), platelet-activating factor (PAF)] or E. coli into the murine cremaster muscle induces target-oriented intravascular adhesion and transmigration as well as polarization and directional interstitial migration of leukocytes towards the locally administered stimuli. Moreover, we describe a crucial role of Rho kinase for the regulation of directional motility and polarization of transmigrated leukocytes in vivo. Finally, combining in vivo RLOT and fluorescence microscopy in Cx3CR1(gfp/gfp) mice (mice exhibiting green fluorescent protein-labeled monocytes), we are able to demonstrate differences in the migratory behavior of monocytes and neutrophils. Taken together, we propose a novel approach for investigating the mechanisms and spatiotemporal dynamics of subtype-specific motility and polarization of leukocytes during their directional interstitial migration in vivo. |
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