Open AccessDetrimental effects of Bartonella henselae are counteracted by l -arginine and nitric oxide in human endothelial progenitor cells
Author(s) -
Paola Salvatore,
Amelia Casamassimi,
Linda Sommese,
Carmela Fiorito,
Alfredo Ciccodicola,
Raffaele Rossiello,
Bice Avallone,
Vincenzo Grimaldi,
Valerio Costa,
Monica Rienzo,
Roberta Colicchio,
Sharon Williams-Ignarro,
Caterina Pagliarulo,
Maria Evelina Prudente,
Ciro Abbondanza,
Florentia Lamberti,
Adone Baroni,
Elisabetta Buommino,
Bartolomeo Farzati,
Maria Antonietta Tufano,
Louis J. Ignarro,
Claudio Napoli
Publication year - 2008
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.0803602105
Subject(s) - bartonella henselae , biology , immune system , progenitor cell , angiogenesis , immunology , tumor necrosis factor alpha , stem cell , microbiology and biotechnology , cancer research , antibody , serology
The recruitment of circulating endothelial progenitor cells (EPCs) might have a beneficial effect on the clinical course of several diseases. Endothelial damage and detachment of endothelial cells are known to occur in infection, tissue ischemia, and sepsis. These detrimental effects in EPCs are unknown. Here we elucidated whether human EPCs internalize Bartonella henselae constituting a circulating niche of the pathogen. B. henselae invades EPCs as shown by gentamicin protection assays and transmission electron microscopy (TEM). Dil-Ac-LDL/lectin double immunostaining and fluorescence-activated cell sorting (FACS) analysis of EPCs revealed EPC bioactivity after infection with B. henselae. Nitric oxide (NO) and its precursor l-arginine (l-arg) exert a plethora of beneficial effects on vascular function and modulation of immune response. Therefore, we tested also the hypothesis that l-arg (1-30 mM) would affect the infection of B. henselae or tumor necrosis factor (TNF) in EPCs. Our data provide evidence that l-arg counteracts detrimental effects induced by TNF or Bartonella infections via NO (confirmed by DETA-NO and L-NMMA experiments) and by modulation of p38 kinase phosphorylation. Microarray analysis indicated several genes involved in immune response were differentially expressed in Bartonella-infected EPCs, whereas these genes returned in steady state when cells were exposed to sustained doses of l-arg. This mechanism may have broad therapeutic applications in tissue ischemia, angiogenesis, immune response, and sepsis.