TRAIL regulates normal erythroid maturation through an ERK-dependent pathway
From the Department of Morphology and Embryology, Human Anatomy Section, University of Ferrara, Ferrara, Italy; The Children's Hospital and Biomedicum Helsinki, Program for Developmental and Reproductive Biology, University of Helsinki, Helsinki, Finland; the Department of Normal Human Morphology, University of Trieste, Trieste, Italy; and the Department of Transfusion Medicine, Study Center "E. Jucci Ciancarelli," "Santo Spirito" Hospital, Pescara, Italy.z[+@?4, 百拇医药
In order to investigate the biologic activity of tumor necrosis factor–related apoptosis-inducing ligand (TRAIL) on human erythropoiesis, glycophorin A (GPA)+ erythroid cells were generated in serum-free liquid phase from human cord blood (CB) CD34+ progenitor cells. The surface expression of TRAIL-R1 was weakly detectable in the early-intermediate phase of erythroid differentiation (days 4-6; dim-intermediate GPA expression), whereas a clear-cut expression of TRAIL-R2 was observed through the entire course of erythroid differentiation (up to days 12-14; bright GPA expression). On the other hand, surface TRAIL-R3 and -R4 were not detected at any culture time. Besides inducing a rapid but small increase of apoptotic cell death, which was abrogated by the pan-caspase inhibitor z-VAD-fmk, the addition of recombinant TRAIL at day 6 of culture inhibited the generation of morphologically mature erythroblasts. Among the intracellular pathways investigated, TRAIL significantly stimulated the extracellular signal-regulated kinase 1/2 (ERK1/2) but not the p38/mitogen-activated protein kinase (MAPK) or the c-Jun NH2-terminal kinase (JNK) pathway. Consistently with a key role of ERK1/2 in mediating the negative effects of TRAIL on erythroid maturation, PD98059, a pharmacologic inhibitor of the ERK pathway, but not z-VAD-fmk or SB203580z[+@?4, 百拇医药
, a pharmacologic inhibitor of p38/MAPK, reverted the antidifferentiative effect of TRAIL on CB-derived erythroblasts.(Paola Secchiero Elisabetta Melloni Markku HeikinheimoSusanna Mannisto Roberta Di Pietro Antonio Iaco)
In order to investigate the biologic activity of tumor necrosis factor–related apoptosis-inducing ligand (TRAIL) on human erythropoiesis, glycophorin A (GPA)+ erythroid cells were generated in serum-free liquid phase from human cord blood (CB) CD34+ progenitor cells. The surface expression of TRAIL-R1 was weakly detectable in the early-intermediate phase of erythroid differentiation (days 4-6; dim-intermediate GPA expression), whereas a clear-cut expression of TRAIL-R2 was observed through the entire course of erythroid differentiation (up to days 12-14; bright GPA expression). On the other hand, surface TRAIL-R3 and -R4 were not detected at any culture time. Besides inducing a rapid but small increase of apoptotic cell death, which was abrogated by the pan-caspase inhibitor z-VAD-fmk, the addition of recombinant TRAIL at day 6 of culture inhibited the generation of morphologically mature erythroblasts. Among the intracellular pathways investigated, TRAIL significantly stimulated the extracellular signal-regulated kinase 1/2 (ERK1/2) but not the p38/mitogen-activated protein kinase (MAPK) or the c-Jun NH2-terminal kinase (JNK) pathway. Consistently with a key role of ERK1/2 in mediating the negative effects of TRAIL on erythroid maturation, PD98059, a pharmacologic inhibitor of the ERK pathway, but not z-VAD-fmk or SB203580z[+@?4, 百拇医药
, a pharmacologic inhibitor of p38/MAPK, reverted the antidifferentiative effect of TRAIL on CB-derived erythroblasts.(Paola Secchiero Elisabetta Melloni Markku HeikinheimoSusanna Mannisto Roberta Di Pietro Antonio Iaco)