Fig. 7. Effect of GTPase inhibition on actin polymerization induced by N. meningitidis. (A) HUVECs were infected for 4 hours with the ROU strain of N. meningitidis. Cells were labeled for bacteria, F-actin and RhoA, and xz section analysis was performed by confocal microscopy at magnification x300.

(B) HUVECs, pretreated with the Rho kinase inhibitor Y27632 at 30 µM in starvation medium for 1 hour, were infected for 4 hours in the presence of the inhibitor and stained for actin (right panel, xy section at magnification x63). The localization of the bacterial colony in the same field is shown by Nomarsky (left panel).

(C) HUVECs were microinjected with the cDNA encoding the dominant-negative form of Cdc42 (Cdc42N¹⁷) coupled to a myc tag, 5 hours prior to cell infection. Cells were then labeled for bacteria, F-actin and the myc tag. xy sections were performed by confocal microscopy at magnification x100. xz sections showed in the lower panels were performed along the indicated lines of the transfected cell and the non transfected cell as control at magnification x100.

(D) HUVECs were microinjected with the cDNA encoding the dominant-negative form of Rac1 (Rac1N¹⁷) coupled to a myc tag, 18 hours prior to cell infection. Cells were then labeled for bacteria, actin and the myc tag. xy sections were performed by confocal microscopy at magnification x63. The arrows in D localize the polymerized actin visible either on control cell or microinjected cell.

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