NF-kappaB translocation and endothelial cell activation is potentiated by macrophage-released signals co-secreted with TNF-alpha and IL-1beta.
OBJECTIVE
Over-expression of the immune response can lead to pathological conditions such as septic shock or chronic inflammation. Endothelial cell activation by pro-inflammatory products of activated macrophages plays a key role in these conditions. Here we examine the response of primary human endothelial cells (HUVEC) to conditioned media (CM) obtained from LPS-activated macrophages. We further characterized the translocation of NF-kappaB in the presence of CM by studying the degradation rate of individual IkappaB isoforms.


RESULTS
We show that, as expected, CM induced NF-kappaB translocation, as well as adhesion capacity in HUVEC. We further show that this response is critically dependent on TNF-alpha and IL1beta naturally present in the CM. However, both the amplitude of NF-kappaB translocation and adhesiveness observed with CM were well beyond the saturation levels attained after the sole stimulation with recombinant TNF-alpha and IL-1beta, either separately or together. Our results show that CM induced a faster degradation of the IkappaB-beta and IkappaB-epsilon isoforms than the recombinant cytokines, leading to an enhanced recruitment of NF-kappaB activity.


CONCLUSIONS
The above results suggest that the physiological context of factors co-secreted by LPS-activated macrophages enhances TNF-alpha mediated endothelial activation.
López-Bojórquez
L N
LN
Departamento de Biología Celular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Circuito Interior S/N Ciudad Universitaria, PO Box 70-243, 04510, México DF, México. llopez@ifc.unam.mx
Arechavaleta-Velasco
F
F
Vadillo-Ortega
F
F
Móntes-Sánchez
D
D
Ventura-Gallegos
J L
JL
Zentella-Dehesa
A
A
D000818:Animals; D015153:Blotting, Western; D002448:Cell Adhesion; D002467:Cell Nucleus / Q000378:metabolism; D002478:Cells, Cultured; D017077:Culture Media, Conditioned / Q000494:pharmacology; D016207:Cytokines / Q000096:biosynthesis; D003593:Cytoplasm / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D042783:Endothelial Cells / Q000166:cytology*; D004730:Endothelium, Vascular / Q000737:chemistry / Q000166:cytology* / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D020672:I-kappa B Proteins / Q000737:chemistry; D007249:Inflammation; D007375:Interleukin-1 / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000737:chemistry; D008264:Macrophages / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism*; D020033:Protein Isoforms; D021381:Protein Transport; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*; D020298:U937 Cells; D014471:Umbilical Veins / Q000166:cytology
D017077:Culture Media, Conditioned; D016207:Cytokines; D020672:I-kappa B Proteins; D007375:Interleukin-1; D008070:Lipopolysaccharides; D016328:NF-kappa B; D020033:Protein Isoforms; D014409:Tumor Necrosis Factor-alpha