Limits...
The effect of enterohemorrhagic E. coli infection on the cell mechanics of host cells.

Chen YQ, Su PT, Chen YH, Wei MT, Huang CH, Osterday K, del Álamo JC, Syu WJ, Chiou A - PLoS ONE (2014)

Bottom Line: When EHEC infects host cells, it releases translocated intimin receptor (Tir) and effector proteins inside the host cells, inducing the rearrangement and accumulation of the F-actin cytoskeleton, a phenotype leading to the formation of pedestals in the apical cell surface, and the growth of stress fibers at the base of the cells.Our results indicated that in EHEC-infected HeLa cells, the focal adhesion area increased and the actin stress fibers became thicker and more aligned.These changes in mechanobiological characteristics might modulate the attachments between EHEC and the host cell to withstand exfoliation, and between the host cell and the extracellular matrix, and might also alter epithelial integrity.

View Article: PubMed Central - PubMed

Affiliation: Institute of Biophotonics, National Yang-Ming University, Taipei, Taiwan, Republic of China.

ABSTRACT
Enterohaemorrhagic E. coli (EHEC) is a type of human pathogenic bacteria. The main virulence characteristics of EHEC include the formation of attaching and effacing lesions (A/E lesions) and the production of one or more Shiga-like toxins, which may induce human uremic complications. When EHEC infects host cells, it releases translocated intimin receptor (Tir) and effector proteins inside the host cells, inducing the rearrangement and accumulation of the F-actin cytoskeleton, a phenotype leading to the formation of pedestals in the apical cell surface, and the growth of stress fibers at the base of the cells. To examine the effect of EHEC infection on cell mechanics, we carried out a series of experiments to examine HeLa cells with and without EHEC infection to quantify the changes in (1) focal adhesion area, visualized by anti-vinculin staining; (2) the distribution and orientation of stress fibers; and (3) the intracellular viscoelasticity, via directional video particle tracking microrheology. Our results indicated that in EHEC-infected HeLa cells, the focal adhesion area increased and the actin stress fibers became thicker and more aligned. The cytoskeletal reorganization induced by EHEC infection mediated a dramatic increase in the cytoplasmic elastic shear modulus of the infected cells, and a transition in the viscoelastic behavior of the cells from viscous-like to elastic-like. These changes in mechanobiological characteristics might modulate the attachments between EHEC and the host cell to withstand exfoliation, and between the host cell and the extracellular matrix, and might also alter epithelial integrity.

Show MeSH

Related in: MedlinePlus

Immunofluorescence microscopy images of the apical region of HeLa cells without vs. with EHEC infection.(A) HeLa cells without EHEC infection; (B) HeLa cells, after being infected with EHEC for 6 hours. HeLa cells were fixed, permeated and stained: green, FITC-label phalloidin for actin; blue, rabbit anti-O157 and Alexa Fluor 405-goat anti-rabbit IgG for EHEC. The merged images in turquoise represent the EHEC induced pedestal formation.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4219835&req=5

pone-0112137-g003: Immunofluorescence microscopy images of the apical region of HeLa cells without vs. with EHEC infection.(A) HeLa cells without EHEC infection; (B) HeLa cells, after being infected with EHEC for 6 hours. HeLa cells were fixed, permeated and stained: green, FITC-label phalloidin for actin; blue, rabbit anti-O157 and Alexa Fluor 405-goat anti-rabbit IgG for EHEC. The merged images in turquoise represent the EHEC induced pedestal formation.

Mentions: We labeled EHEC by Alexa Fluor 405 (blue) and actin via FITC-phalloidin staining (green) and examined the apical and basal regions of HeLa cells without EHEC infection vs. cells that had been infected for 6 hours. The resulting images revealed actin accumulation consistent with the formation of pedestals in the apical region of the infected HeLa cells (Fig. 3B). As expected, the pedestals were not observed in the control HeLa cells (Fig. 3A). Besides, EHEC infection induced actin polymerization and bundling into stress fibers in the basal region of the cells (Fig. 4B), but the stress fibers were less discernable in the basal region of the non-infected cells (Fig. 4A).


The effect of enterohemorrhagic E. coli infection on the cell mechanics of host cells.

Chen YQ, Su PT, Chen YH, Wei MT, Huang CH, Osterday K, del Álamo JC, Syu WJ, Chiou A - PLoS ONE (2014)

Immunofluorescence microscopy images of the apical region of HeLa cells without vs. with EHEC infection.(A) HeLa cells without EHEC infection; (B) HeLa cells, after being infected with EHEC for 6 hours. HeLa cells were fixed, permeated and stained: green, FITC-label phalloidin for actin; blue, rabbit anti-O157 and Alexa Fluor 405-goat anti-rabbit IgG for EHEC. The merged images in turquoise represent the EHEC induced pedestal formation.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4219835&req=5

pone-0112137-g003: Immunofluorescence microscopy images of the apical region of HeLa cells without vs. with EHEC infection.(A) HeLa cells without EHEC infection; (B) HeLa cells, after being infected with EHEC for 6 hours. HeLa cells were fixed, permeated and stained: green, FITC-label phalloidin for actin; blue, rabbit anti-O157 and Alexa Fluor 405-goat anti-rabbit IgG for EHEC. The merged images in turquoise represent the EHEC induced pedestal formation.
Mentions: We labeled EHEC by Alexa Fluor 405 (blue) and actin via FITC-phalloidin staining (green) and examined the apical and basal regions of HeLa cells without EHEC infection vs. cells that had been infected for 6 hours. The resulting images revealed actin accumulation consistent with the formation of pedestals in the apical region of the infected HeLa cells (Fig. 3B). As expected, the pedestals were not observed in the control HeLa cells (Fig. 3A). Besides, EHEC infection induced actin polymerization and bundling into stress fibers in the basal region of the cells (Fig. 4B), but the stress fibers were less discernable in the basal region of the non-infected cells (Fig. 4A).

Bottom Line: When EHEC infects host cells, it releases translocated intimin receptor (Tir) and effector proteins inside the host cells, inducing the rearrangement and accumulation of the F-actin cytoskeleton, a phenotype leading to the formation of pedestals in the apical cell surface, and the growth of stress fibers at the base of the cells.Our results indicated that in EHEC-infected HeLa cells, the focal adhesion area increased and the actin stress fibers became thicker and more aligned.These changes in mechanobiological characteristics might modulate the attachments between EHEC and the host cell to withstand exfoliation, and between the host cell and the extracellular matrix, and might also alter epithelial integrity.

View Article: PubMed Central - PubMed

Affiliation: Institute of Biophotonics, National Yang-Ming University, Taipei, Taiwan, Republic of China.

ABSTRACT
Enterohaemorrhagic E. coli (EHEC) is a type of human pathogenic bacteria. The main virulence characteristics of EHEC include the formation of attaching and effacing lesions (A/E lesions) and the production of one or more Shiga-like toxins, which may induce human uremic complications. When EHEC infects host cells, it releases translocated intimin receptor (Tir) and effector proteins inside the host cells, inducing the rearrangement and accumulation of the F-actin cytoskeleton, a phenotype leading to the formation of pedestals in the apical cell surface, and the growth of stress fibers at the base of the cells. To examine the effect of EHEC infection on cell mechanics, we carried out a series of experiments to examine HeLa cells with and without EHEC infection to quantify the changes in (1) focal adhesion area, visualized by anti-vinculin staining; (2) the distribution and orientation of stress fibers; and (3) the intracellular viscoelasticity, via directional video particle tracking microrheology. Our results indicated that in EHEC-infected HeLa cells, the focal adhesion area increased and the actin stress fibers became thicker and more aligned. The cytoskeletal reorganization induced by EHEC infection mediated a dramatic increase in the cytoplasmic elastic shear modulus of the infected cells, and a transition in the viscoelastic behavior of the cells from viscous-like to elastic-like. These changes in mechanobiological characteristics might modulate the attachments between EHEC and the host cell to withstand exfoliation, and between the host cell and the extracellular matrix, and might also alter epithelial integrity.

Show MeSH
Related in: MedlinePlus