ERYTHROPOIETIN DIFFERENTIAL ACTION ON MATURE AND IMMATURE SH-SY5YCELL CULTURES

WENKER SHIRLEY; CHAMORRO M EUGENIA; VOTA DAIANA; VITTORI DANIELA; NESSE ALCIRA

Córdoba, Argentina

Congreso; I Reunión Conjunta de Neurociencias (IRCN) Taller Argentino de Neurociencias y a la Sociedad Argentina de Investigación en Neurociencias; 2009

SAN y TAN

Erythropoietin (Epo) has emerged as a multifunctional factor that could play animportant role in tissues outside the hematopoietic system. In previous works, we foundan Epo antiapoptotic action on undifferentiated neuronal SH-SY5Y cells againstcytotoxicity induced by stauroporine (STP) or TNF-alpha. Then, we investigatedwhether the protective effect of Epo could be detected in neuronal cells differentiated byretinoic acid (RA). Immature and mature stages of SH-SY5Y cells were exposed toproapoptotic agents. In immature cell cultures, STP, TNF-alpha or hypoxia significantlyreduced cell viability (MTT assay) and increased apoptosis (Hoechst staining) (STP49±3, TNF 49±3, H 28±2, P0.05 vs. Control). However, cell resistance was observedafter RA differentiated cells (RA-STP 28±3, RA-TNF 15±3, RA-H 7±2, P0.05 vs.Control). Pretreatment of undifferentiated cells with Epo significantly (P0.05) preventedcell death against STP (23±3), TNF (20±6), or hypoxia (7±2). These effects can bepartially explained by Bcl-xL and Bcl-2 upregulation (RT-PCR and Western Blotting).Instead, no additional effect of Epo was observed upon differentiated cells. Inhibition ofJak-2 pathway and ARNm analysis of the erythropoietin receptor (Real time PCR)suggest that this lack of response could be associated to receptor downregulation. Inconclusion, Epo is able to protect immature SH-SY5Y cells from cell death induced bySTP, TNF-alpha or hypoxia but is uncapable to affect RA-differentiated cells. A closedependence of the Epo neuroprotective action on the degree of cell differentiation couldbe one explanation. This differential behavior of immature and mature neuronal cellscould be important in the pharmacological effect of Epo.Key words: Erythropoietin, Neuroprotection, Differentiation