Title:Phenotypic and Genetic Evaluation of the Influence of Pseudomonas aeruginosa Culture Fractions on the Human Mesenchymal Stem Cells Viability, Apoptotic Pathways and Cytokine Profile
Volume: 12
Issue: 2
Author(s): Alina Maria Holban, Coralia Bleotu, Mariana Carmen Chifiriuc and Veronica Lazar
Affiliation:
Keywords:
Apoptosis, interleukins, mesenchymal stem cells, pathogenesis, Pseudomonas aeruginosa.
Abstract: The objective of this study was to investigate the effects of P. aeruginosa PAO1 cellular and
soluble culture fractions on human mesenchymal stem cells (MSCs) death signaling pathways and cytokine
profile. The bone marrow isolated MSCs, incubated for different periods of time with one of the
three P. aeruginosa PAO1 culture fractions, i.e. low density whole cultures, heat inactivated bacterial
cultures sediments and sterile supernatants, were submitted to the following assays: i) fluorescence microscopy
evaluation of cellular morphology and viability; ii) bax, caspase 9, relA and bcl-2 genes expression
analysis by qRT-PCR; and iii) quantification of the level of IL-1β, IL-6, IL-8 and IL-10 cytokines
released in the MSCs supernatants determined by ELISA. Results were statistically analyzed using the
GraphPad In Stat software. The PAO1 whole cultures exhibited the most relevant influences, impacting
on MSCs morphology and viability, interfering with apoptotic pathways and significantly stimulating the
production of IL-1β and IL-10, while decreasing the production of IL-6 and IL-8. The culture supernatants
increased the production of IL-1β and reduced the secretion of all other tested cytokines, while
heat-inactivated bacterial cells significantly stimulated both IL-1β and IL-10 production. These data could
suggest that in vivo, the fate of P. aeruginosa infection depends on the proportion between different bacterial
culture fractions (i.e. the number of viable bacterial cells, the number of dead cells and the amount
of bacterial soluble products accumulated locally) that could be influenced by the initial infective dose, by
the host defense mechanisms, and also by the administered antimicrobial treatment that may thus interfere
with the evolution and magnitude of the induced lesions.
