title: Mechanisms of uremic erythrocyte-induced adhesion of human monocytes to cultured endothelial cells.
abstract: In end-stage renal disease (ESRD) endothelium may represent a key target for the action of circulating elements, such as modified erythrocytes (RBC) and/or plasmatic factors, that may facilitate inflammation and the vasculopathy associated with uremia. We have previously demonstrated that phosphatidylserine (PS) exposure on the surface of RBC from ESRD patients increases RBC-human umbilical vein endothelial cell (HUVEC) interactions and causes decreased nitric oxide (NO) production. We postulated that, besides the pro-inflammatory effects due to decreased NO bio-availability, enhanced ESRD-RBC-HUVEC interactions might directly stimulate pro-inflammatory pathways leading to increased vascular adhesion molecule expression. ESRD-RBC-endothelial cell interactions induced a time-dependent up-regulation of VCAM-1 and ICAM-1 (measured by Western blot (WB) and real-time PCR), associated with mitogen-activated protein kinase (MAPK) activation and impairment of the Akt/endothelial nitric oxide synthase (eNOS) signaling cascade, measured by WB. In reconstitution experiments, normal RBC incubated with uremic plasma showed increased PS exposure and significantly increased VCAM-1 and ICAM-1 mRNA levels when incubated on HUVEC. Interestingly, ESRD-RBC induced increased expression of adhesion molecules was prevented by Annexin-V (AnV, able to mask PS on RBC surface), anti-integrin-alpha(v)beta3, anti-thrombospondin-1 (TSP-1), and PD98059 (a selective inhibitor of MAPK phosphorylation). Moreover, AnV reversed the ESRD-RBC effects on MAPK and Akt/eNOS signaling pathways. Our data demonstrate that, possibly via a direct interaction with the endothelial thrombospondin-(alpha(v)beta3) integrin complex, ESRD-RBC-HUVEC adhesion induces a vascular inflammatory phenotype. Thus, intervention targeting ESRD-RBC increased adhesion to endothelium and/or MAPK and Akt/eNOS pathways may have the potential to prevent vascular lesions under uremic conditions.
authors.affiliation: Department of Biomorphology, University G. d'Annunzio, Aging Research Center, Ce.S.I., G. d'Annunzio University Foundation, Chieti-Pescara, Italy. pandolfi@unich.it
authors.forename: Assunta
authors.initials: A
authors.lastname: Pandolfi
authors.forename: Natalia
authors.initials: N
authors.lastname: Di Pietro
authors.forename: Vittorio
authors.initials: V
authors.lastname: Sirolli
authors.forename: Annalisa
authors.initials: A
authors.lastname: Giardinelli
authors.forename: Sara
authors.initials: S
authors.lastname: Di Silvestre
authors.forename: Luigi
authors.initials: L
authors.lastname: Amoroso
authors.forename: Pamela
authors.initials: P
authors.lastname: Di Tomo
authors.forename: Fabio
authors.initials: F
authors.lastname: Capani
authors.forename: Agostino
authors.initials: A
authors.lastname: Consoli
authors.forename: Mario
authors.initials: M
authors.lastname: Bonomini
mesh_terms: D000368:Aged; D015153:Blotting, Western; D016022:Case-Control Studies; D002448:Cell Adhesion / Q000502:physiology*; D018929:Cell Culture Techniques; D002478:Cells, Cultured; D016895:Culture Media, Serum-Free; D042783:Endothelial Cells / Q000502:physiology*; D004730:Endothelium, Vascular / Q000166:cytology; D004912:Erythrocytes / Q000473:pathology / Q000502:physiology*; D005260:Female; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000032:analysis / Q000378:metabolism; D007676:Kidney Failure, Chronic / Q000097:blood / Q000150:complications / Q000201:enzymology; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D009000:Monocytes / Q000502:physiology*; D052250:Nitric Oxide Synthase Type III / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D012333:RNA, Messenger / Q000032:analysis; D013997:Time Factors; D020298:U937 Cells; D014471:Umbilical Veins / Q000166:cytology; D014511:Uremia / Q000097:blood* / Q000201:enzymology / Q000503:physiopathology; D019010:Vascular Cell Adhesion Molecule-1 / Q000032:analysis / Q000378:metabolism
chemical_list: D016895:Culture Media, Serum-Free; D012333:RNA, Messenger; D019010:Vascular Cell Adhesion Molecule-1; D018799:Intercellular Adhesion Molecule-1; D052250:Nitric Oxide Synthase Type III