Медицинская иммунология (Oct 2017)
EFFECT OF ARGININE DEIMINASE FROM STREPTOCOCCUS PYOGENES ON CYTOSKELETON STRUCTURE AND MIGRATION ACTIVITY OF HUMAN ENDOTHELIAL CELLS
Abstract
There is a growing body of data about the cytopathic effect of bacterial arginine deiminase on human endothelial cells, but the precise mechanisms of endothelial dysfunction caused by the activity of the enzyme remain poorly understood. Activity of arginine deiminase causes arginine depletion in the microenvironment of the host organism cells. In view that arginylation of beta-actin regulates actin cytoskeleton structure and cell motility, we proposed that the cytopathic effect of arginine deiminase may be associated with disruption of actin in the cytoskeleton of endothelial cells. The aim of this study was to investigate the effect of arginine deiminase from S. pyogenes on migration and actin cytoskeleton structure of the human endothelial cells, line EA.hy926. The supernatant of sonicated S. pyogenes M49-16, its isogenic mutant with a deletion of the arginine deiminase gene (S. pyogenes M49-16delAD), supernatant of sonicated S. pyogenes M22, and arginine deiminase isolated from the latter strain were used. The effect of bacterial factors on migration activity of endothelial cells was studied in the model of "wound healing" in vitro. To analyze the influence of bacterial factors on the actin cytoskeleton structure, cells were stained with phalloidin-rhodamine. It was shown that supernatants of destroyed S. pyogenes, as well as arginine deiminase significantly reduced the migration activity of endothelial cells and altered the structure of their actin cytoskeleton. The supernatants of destroyed S. pyogenes M49-16delAD with deleted gene of arginine deiminase showed a significantly reduced ability to suppress cell migration as compared with the supernatant of sonicated S. pyogenes M49-16. No significant differences were revealed in the structure of actin filaments in cells cultured in the presence of supernatants of destroyed S. pyogenes M19-16, and cells cultured in the presence of isogenic mutant S. pyogenes M4916delAD. Adding exogenous arginine to the cells cultured with supernatants of destroyed S. pyogenes did not restore their migratory activity and the structure of their actin cytoskeleton. However, if arginine deficiency caused by the activity of arginine deiminase was compensated, endothelial cells migration activity was restored, and the structure of actin cytoskeleton was recovered. A decrease of migration activity of endothelial cells under the influence of streptococcal arginine deiminase was due to the disruption of actin cytoskeleton structure.
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