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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.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.

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.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.

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