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The new anti-actin agent dihydrohalichondramide reveals fenestrae-forming centers in hepatic endothelial cells.

Braet F, Spector I, Shochet N, Crews P, Higa T, Menu E, de Zanger R, Wisse E - BMC Cell Biol. (2002)

Bottom Line: In this study, we investigated the effects of two new actin-binding agents on fenestrae dynamics.Dihydrohalichondramide induces fenestrae-forming centers, whereas halichondramide only revealed fenestrae-forming centers without attached rows of fenestrae with increasing diameter.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. (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.

View Article: PubMed Central - HTML - PubMed

Affiliation: Laboratory for Cell Biology and Histology, Free University of Brussels (VUB), Laarbeeklaan 103, 1090 Brussels-Jette, Belgium. filipbra@cyto.vub.ac.be

ABSTRACT

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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Diameter distribution of fenestrae, showing values for control, HALI, and di-h-HALI – treated LSECs, extending the data of fenestrae diameter of Table1. From this graph, we can conclude that treatment of LSECs with HALI or di-h-HALI results in smaller fenestrae diameters.
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Figure 4: Diameter distribution of fenestrae, showing values for control, HALI, and di-h-HALI – treated LSECs, extending the data of fenestrae diameter of Table1. From this graph, we can conclude that treatment of LSECs with HALI or di-h-HALI results in smaller fenestrae diameters.

Mentions: We also measured the effect of the agents on fenestrae diameter at the end of treatment (Table 1 and Fig. 4). Fenestrae of HALI- or Di-h-HALI-treated LSECs have a mean diameter of 182 ± 75 nm and 165 ± 60 nm, respectively. A significant difference was found between the control and HALI- or Di-h-HALI-treated LSECs at the 0.0001 confidence level (Table 1, Fig. 4).


The new anti-actin agent dihydrohalichondramide reveals fenestrae-forming centers in hepatic endothelial cells.

Braet F, Spector I, Shochet N, Crews P, Higa T, Menu E, de Zanger R, Wisse E - BMC Cell Biol. (2002)

Diameter distribution of fenestrae, showing values for control, HALI, and di-h-HALI – treated LSECs, extending the data of fenestrae diameter of Table1. From this graph, we can conclude that treatment of LSECs with HALI or di-h-HALI results in smaller fenestrae diameters.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC101387&req=5

Figure 4: Diameter distribution of fenestrae, showing values for control, HALI, and di-h-HALI – treated LSECs, extending the data of fenestrae diameter of Table1. From this graph, we can conclude that treatment of LSECs with HALI or di-h-HALI results in smaller fenestrae diameters.
Mentions: We also measured the effect of the agents on fenestrae diameter at the end of treatment (Table 1 and Fig. 4). Fenestrae of HALI- or Di-h-HALI-treated LSECs have a mean diameter of 182 ± 75 nm and 165 ± 60 nm, respectively. A significant difference was found between the control and HALI- or Di-h-HALI-treated LSECs at the 0.0001 confidence level (Table 1, Fig. 4).

Bottom Line: In this study, we investigated the effects of two new actin-binding agents on fenestrae dynamics.Dihydrohalichondramide induces fenestrae-forming centers, whereas halichondramide only revealed fenestrae-forming centers without attached rows of fenestrae with increasing diameter.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. (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.

View Article: PubMed Central - HTML - PubMed

Affiliation: Laboratory for Cell Biology and Histology, Free University of Brussels (VUB), Laarbeeklaan 103, 1090 Brussels-Jette, Belgium. filipbra@cyto.vub.ac.be

ABSTRACT

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.

Show MeSH
Related in: MedlinePlus