Action of modified erithropoietins on endothelial cells in a proinflammatory environment.

CHAMORRO MARÍA EUGENIA; SCHIAVINATTO DANIELA; MALTANERI ROMINA EUGENIA; SCHIAPPACASSE AGUSTINA; NESSE ALCIRA; VITTORI DANIELA

CABA

Congreso; LXII Reunión Científica Anual de la Sociedad Argentina de Investigación Clínica; 2017

SAIC

Erythropoietin (Epo), the erythropoiesis growthfactor, is also known as an antiapoptotic agent. In this context, carbamylated Epo(cEpo) maintains the neuroprotective effect but fails to stimulateerythropoiesis. Despite the benefit of Epo treatment to overcome anemiaassociated to different pathologies, a significant number of patients,particularly those with cardiovascular or chronic renal diseases, fail torespond. This may be related to the simultaneous presence of other independentrisk factors, such as hyperhomocysteinemia. This study was aimed at identifyingEpo structural changes due to carbamylation and N-homocysteinylation, and investigating whether these changes couldaffect Epo activity on EA.hy926 endothelial cells in a proinflammatoryenvironment. cEpo was prepared by reaction with potassium cyanatewhile homocysteine thiolactone was incubated with Epo to yield the N-homocysteinylated protein. Analysis bygel and capillary electrophoresis revealed structural changes with respect tothe native protein. Wound healing assays showed a stimulatory effect of TNF-αon cell migration which was significantly increased by TNF-α+Epo combination (C21±2%, *TNF-α 44±3%, Epo 30±2%, *EpoTNF-α 66±4%, *P<0.05, n=6),mediated by amechanism involving EpoR induction. A similar effectof TNF-α+Epo was found on VCAM and ICAM mRNA expression (Real Time PCR, respectto C=1; VCAM: *TNF-α 22±3%, Epo 2±1%, *EpoTNF-α 36±2%, *P<0.01; ICAM: *TNF-α76±9%, Epo 3±1%, *EpoTNF-α 123±5%, *P<0.05, n=3) as well as in monocytic celladhesion assays (Fluorescence microscopy and fluorometric quantification withmonocytic THP1 cells, n=6).The fact that no such activities were shown by themodified Epos suggests altered Epo function due to structural changes. Insummary, the proangiogenic ability of Epo, enhanced in the presence ofproinflammatory factors, might favor its action as a vascular protectant inischemia and a mediator of lymphocyte migration dependent of adhesionmolecules.