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Ischemia-induced apoptosis of intestinal epithelial cells correlates with altered integrin distribution and disassembly of F-actin triggered by calcium overload.

Jia Z, Chen Q, Qin H - J. Biomed. Biotechnol. (2012)

Bottom Line: Results.Verapamil attenuated both changes of integrins and F-actin.Conclusions.

View Article: PubMed Central - PubMed

Affiliation: Department of General Surgery, Shanghai Sixth People's Hospital, Shanghai Jiao Tong University, Shanghai 200233, China.

ABSTRACT
The present study examined intestinal epithelial cell (IEC) integrin distribution and disassembly of actin cytoskeleton in response to ischemia-anoxia. Protective effects of calcium channel blocker(CCB) were further examined to explore underlying mechanisms of cellular injury. Materials and Methods. Primary cultures of rat IECs and an in vitro model of ischemia/anoxia were established. IECs were exposed to ischemia/anoxia in the presence and absence of verapamil. The extent of exfoliation was determined using light microscopy while apoptosis rate was measured using flow cytometry. Changes in intracellular calcium, the distribution of integrins and the morphology of F-actin were assessed by confocal microscopy. Results. Detachment and apoptosis of IECs increased following ischemia/anoxia-induced injury. Treatment with verapamil inhibited the detachment and apoptosis. Under control conditions, the strongest fluorescent staining for integrins appeared on the basal surface of IECs while this re-distributed to the apical membrane in response to ischemic injury. Depolymerization of F-actin was also observed in the injured cells. Verapamil attenuated both changes of integrins and F-actin. Conclusions. Redistribution of integrins and disruption of F-actin under ischemia/anoxia injury is associated with IEC detachment and increased apoptosis. These events appeared to be triggered by an increase in Ca(2+)(i) suggesting a potential use for CCB in prevention and treatment of intestinal injury.

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F-actin visualization by phalloidin labeling as analyzed by confocal microscopy. Scale bar = 10 μm (A: control group; B: injury group; C: Verapamil-treated group).
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fig6: F-actin visualization by phalloidin labeling as analyzed by confocal microscopy. Scale bar = 10 μm (A: control group; B: injury group; C: Verapamil-treated group).

Mentions: The effect of ischemia/anoxia on organization of the actin cytoskeleton is shown in Figure 2. The control group showed a well-organized actin filament cytoskeleton consisting of thin bundles of stress fibers arranged across the cell bodies in a largely parallel pattern. In the ischemia/anoxia group, F-actin bundles were not apparent and only clumps of F-actin clumps were visible, indicating depolymerization of the actin cytoskeleton. In contrast, when ischemia/anoxia group was pretreated with verapamil, the F-actin bundles appeared very similar to that of control animals, indicating that the Ca2+ channel blocker prevented the ischemia-induced alterations in the actin cytoskeleton (Figure 6).


Ischemia-induced apoptosis of intestinal epithelial cells correlates with altered integrin distribution and disassembly of F-actin triggered by calcium overload.

Jia Z, Chen Q, Qin H - J. Biomed. Biotechnol. (2012)

F-actin visualization by phalloidin labeling as analyzed by confocal microscopy. Scale bar = 10 μm (A: control group; B: injury group; C: Verapamil-treated group).
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3369571&req=5

fig6: F-actin visualization by phalloidin labeling as analyzed by confocal microscopy. Scale bar = 10 μm (A: control group; B: injury group; C: Verapamil-treated group).
Mentions: The effect of ischemia/anoxia on organization of the actin cytoskeleton is shown in Figure 2. The control group showed a well-organized actin filament cytoskeleton consisting of thin bundles of stress fibers arranged across the cell bodies in a largely parallel pattern. In the ischemia/anoxia group, F-actin bundles were not apparent and only clumps of F-actin clumps were visible, indicating depolymerization of the actin cytoskeleton. In contrast, when ischemia/anoxia group was pretreated with verapamil, the F-actin bundles appeared very similar to that of control animals, indicating that the Ca2+ channel blocker prevented the ischemia-induced alterations in the actin cytoskeleton (Figure 6).

Bottom Line: Results.Verapamil attenuated both changes of integrins and F-actin.Conclusions.

View Article: PubMed Central - PubMed

Affiliation: Department of General Surgery, Shanghai Sixth People's Hospital, Shanghai Jiao Tong University, Shanghai 200233, China.

ABSTRACT
The present study examined intestinal epithelial cell (IEC) integrin distribution and disassembly of actin cytoskeleton in response to ischemia-anoxia. Protective effects of calcium channel blocker(CCB) were further examined to explore underlying mechanisms of cellular injury. Materials and Methods. Primary cultures of rat IECs and an in vitro model of ischemia/anoxia were established. IECs were exposed to ischemia/anoxia in the presence and absence of verapamil. The extent of exfoliation was determined using light microscopy while apoptosis rate was measured using flow cytometry. Changes in intracellular calcium, the distribution of integrins and the morphology of F-actin were assessed by confocal microscopy. Results. Detachment and apoptosis of IECs increased following ischemia/anoxia-induced injury. Treatment with verapamil inhibited the detachment and apoptosis. Under control conditions, the strongest fluorescent staining for integrins appeared on the basal surface of IECs while this re-distributed to the apical membrane in response to ischemic injury. Depolymerization of F-actin was also observed in the injured cells. Verapamil attenuated both changes of integrins and F-actin. Conclusions. Redistribution of integrins and disruption of F-actin under ischemia/anoxia injury is associated with IEC detachment and increased apoptosis. These events appeared to be triggered by an increase in Ca(2+)(i) suggesting a potential use for CCB in prevention and treatment of intestinal injury.

Show MeSH
Related in: MedlinePlus