Effect of platelet-activating factor on the growth of human erythroid and myeloid CD34+ progenitors.
We have assessed the effect of platelet-activating factor (PAF), a biologically active phospholipid present in the human marrow, on the growth of human marrow and blood CD34+ progenitors. While the metabolization rate of PAF by CD34+ cells is low (weak acetylhydrolase and acylation processes) it is readily catabolized by the acetylhydrolase activity present in the growth medium (10% fetal calf serum + 10% 5637-conditioned medium). Treatment of marrow CD34+ cells with the non-metabolizable PAF agonist C-PAF (1 nM to 100 nM) immediately before semi-solid culture significantly (P < 0.01) decreased the number of BFU-E but not of CFU-GM colonies. Treatment of marrow or blood CD34+ cells with C-PAF (10-100 nM) for 3 days in liquid medium before semi-solid culture significantly (P < 0.01) decreased the number of BFU-E and CFU-GM colonies. Treatment of blood CD34+ cells with the two PAF receptor antagonists CV 3988 and BN 52021 (1 microM) had no significant effect on the number of BFU-E and CFU-GM colonies suggesting no role of endogenous PAF in these processes. These results show that exogenous PAF downregulates human erythropoiesis and myelopoiesis, a result that might be of importance during inflammatory states.
Dupuis
F
F
Laboratoire d'Hématologie Expérimentale, Faculté de Médecine, Limoges, France.
Gachard
N
N
Allegraud
A
A
Dulery
C
C
Praloran
V
V
Denizot
Y
Y
D018952:Antigens, CD34; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D015672:Erythroid Precursor Cells / Q000187:drug effects*; D006801:Humans; D010972:Platelet Activating Factor / Q000494:pharmacology*
D018952:Antigens, CD34; D010972:Platelet Activating Factor