Erythropoietin fosters both intrinsic and extrinsic neuronal protection through modulation of microglia, Akt1, Bad, and caspase-mediated pathways - PubMed (original) (raw)
EPO protects neurons from injury through the modulation of caspase 8, caspase 1, and caspase 3-like activities. (a) Neurons were exposed to NO (NOC-9 or SNP, 300 μ
M
) and caspase 8-, caspase 1-, and caspase 3-like activities were assessed 12 h later through their respective colorimetric substrates. Pretreatment with EPO (1 U ml−1) or the caspase inhibitors (C-I, 50 μ
M
) for caspase 8 (IETD), caspase 1 (YVAD), and caspase 3 (DEVD) 1 h prior to NO significantly inhibited the increase in the activity of caspase 8, caspase 1, and caspase 3 induced by NO (*P<0.01 vs NO). (b) Neurons were pretreated with EPO (1 U ml−1) alone or in combination with an inhibitor of caspase 8 (IETD, 50 μ
M
), caspase 1 (YVAD, 50 μ
M
), or caspase 3 (DEVD, 50 μ
M
). No enhanced or synergistic protection was observed during the application of each caspase inhibitor combined with EPO when compared with cultures exposed to EPO and NO alone. (c) Neurons were pretreated with a caspase 8 inhibitor (IETD, 50 μ
M
), a caspase 1 inhibitor (YVAD, 50 μ
M
), or a caspase 3 inhibitor (DEVD, 50 μ
M
) 1 h prior to NO (NOC-9 or SNP, 300 μ
M
) and DNA fragmentation with TUNEL was determined 24 h following NO exposure (*P<0.01 vs NO). (d) Neurons were pretreated with a caspase 8 inhibitor (IETD, 50 μ
M
), a caspase 1 inhibitor (YVAD, 50 μ
M
), or a caspase 3 inhibitor (DEVD, 50 μ
M)
1 h prior to NO (NOC-9 or SNP, 300 μ
M
) and membrane PS exposure with annexin V PE was determined 24 h following NO exposure (*P<0.01 vs NO). In all cases, to simplify the figures, the results of the two NO donors were combined and control = untreated neurons.