Background: Liver sinusoidal endothelial cells (LSECs) react to different anti-actin agents by increasing their number of fenestrae. A new structure related to fenestrae formation could be observed when LSECs were treated with misakinolide. In this study, we investigated the effects of two new actin-binding agents on fenestrae dynamics. High-resolution microscopy, including immunocytochemistry and a combination of fluorescence- and scanning electron microscopy was applied.
Results: Halichondramide and dihydrohalichondramide disrupt microfilaments within 10 minutes and double the number of fenestrae in 30 minutes. Dihydrohalichondramide induces fenestrae-forming centers, whereas halichondramide only revealed fenestrae-forming centers without attached rows of fenestrae with increasing diameter. Correlative microscopy showed the absence of actin filaments (F-actin) in sieve plates and fenestrae-forming centers. Comparable experiments on umbilical vein endothelial cells and bone marrow sinusoidal endothelial cells revealed cell contraction without the appearance of fenestrae or fenestrae-forming centers.
Conclusion: (I) A comparison of all anti-actin agents tested so far, revealed that the only activity that misakinolide and dihydrohalichondramide have in common is their barbed end capping activity; (II) this activity seems to slow down the process of fenestrae formation to such extent that it becomes possible to resolve fenestrae-forming centers; (III) fenestrae formation resulting from microfilament disruption is probably unique to LSECs.
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http://dx.doi.org/10.1186/1471-2121-3-7 | DOI Listing |
Hepatology
February 2019
Centre for Nanometer-Scale Science and Advanced Materials (NANOSAM), Faculty of Physics, Astronomy, and Applied Computer Science, Jagiellonian University, Krakow, Poland.
The fenestrae of liver sinusoidal endothelial cells (LSECs) allow passive transport of solutes, macromolecules, and particulate material between the sinusoidal lumen and the liver parenchymal cells. Until recently, fenestrae and fenestrae-associated structures were mainly investigated using electron microscopy on chemically fixed LSECs. Hence, the knowledge about their dynamic properties has remained to date largely elusive.
View Article and Find Full Text PDFMicrosc Res Tech
March 2007
Australian Key Centre for Microscopy and Microanalysis, The University of Sydney, New South Wales, Australia.
Correlative microscopy has become increasingly important for the analysis of the structure, function, and dynamics of cells. This is largely due to the result of recent advances in light-, probe-, laser- and various electron microscopy techniques that facilitate three-dimensional studies. Furthermore, the improved understanding in the past decade of imaging cell compartments in the third dimension has resulted largely from the availability of powerful computers, fast high-resolution CCD cameras, specifically developed imaging analysis software, and various probes designed for labeling living and or fixed cells.
View Article and Find Full Text PDFLiver Int
December 2004
Australian Key Centre for Microscopy and Microanalysis, Electron Microscope Unit, University of Sydney, Sydney, NSW 2006, Australia.
This review discusses the current state of knowledge about the ultrastructure of hepatic endothelial fenestrae. The application of different high-resolution correlative microscopic methods during the past decade facilitated the accumulation of new insights in the morpho-functional and structural organization of the liver sieve. The data gathered unambiguously show the involvement of special domains in de novo formation and disappearance of fenestrae, and focuses future research into the (supra)molecular structure of the fenestrae-forming center, defenestration center and fenestrae-associated cytoskeleton ring by using cryo-electron microscopic tomography.
View Article and Find Full Text PDFBMC Cell Biol
March 2002
Laboratory for Cell Biology and Histology, Free University of Brussels (VUB), Laarbeeklaan 103, 1090 Brussels-Jette, Belgium.
Background: Liver sinusoidal endothelial cells (LSECs) react to different anti-actin agents by increasing their number of fenestrae. A new structure related to fenestrae formation could be observed when LSECs were treated with misakinolide. In this study, we investigated the effects of two new actin-binding agents on fenestrae dynamics.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
November 1998
Laboratory for Cell Biology and Histology, Free University of Brussels, Laarbeeklaan 103, 1090 Brussels-Jette, Belgium.
Hepatic endothelial fenestrae are dynamic structures that act as a sieving barrier to control the extensive exchange of material between the blood and the liver parenchyma. Alterations in the number or diameter of fenestrae by drugs, hormones, toxins, and diseases can produce serious perturbations in liver function. Previous studies have shown that disassembly of actin by cytochalasin B or latrunculin A caused a remarkable increase in the number of fenestrae and established the importance of the actin cytoskeleton in the numerical dynamics of fenestrae.
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