K-CL co-transport plays an important role in normal and beta thalassemic erythropoiesis.
OBJECTIVE
Cell volume changes are hallmarks of both cell maturation and apoptosis, and are paralleled by modulation of membrane ion transport pathways. We evaluated the possible role of K-Cl co-transport (KCC) in both normal and beta-thalassemic erythropoiesis in vitro.


METHODS
We studied the effects of the KCC inhibitor, DIOA, on cell proliferation and differentiation, on expression of KCC mRNA and polypeptides, and on expression of cell cycle and apoptosis genes in in vitro liquid-cultures of CD34(+) cells from normal and beta-thalassemic subjects.


RESULTS
beta-thalassemic erythroid precursors showed increased abundance of KCC1-3 mRNA and of KCC polypeptides in late erythropoiesis. DIOA markedly modified the composition of normal erythroid precursors, promoting differentiation and arrest at the polychromatic erythroblast stage and resulting in a precursor distribution profile similar to that of untreated beta-thalassemic cells. DIOA up-regulated cyclin-D mRNA levels in late erythropoiesis in both cell models, paralleling changes in the percentage of S-phase-cells. Caspase-3 activity in late erythropoiesis declined to similar degrees in both cell models. DIOA did not modify caspase-3 or -8 mRNA levels.


CONCLUSIONS
Ineffective erythropoiesis of in vitro cultured beta-thalassemic cells is likely related to impaired cell maturation. KCC activity appears to contribute to erythroid cell growth during late erythropoiesis.
De Franceschi
Lucia
L
Department of Clinical and Experimental Medicine, University of Verona, Italy.
Ronzoni
Luisa
L
Cappellini
Maria Domenica
MD
Cimmino
Flora
F
Siciliano
Angela
A
Alper
Seth L
SL
Servedio
Veronica
V
Pozzobon
Christian
C
Iolascon
Achille
A
D015415:Biomarkers; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D041905:Erythroid Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D004920:Erythropoiesis; D006262:Health; D006801:Humans; D026902:Potassium Channel Blockers / Q000494:pharmacology; D011189:Potassium Chloride / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D049994:Sodium Potassium Chloride Symporter Inhibitors; D028021:Sodium-Potassium-Chloride Symporters / Q000235:genetics / Q000378:metabolism*; D017086:beta-Thalassemia / Q000378:metabolism*
D015415:Biomarkers; D026902:Potassium Channel Blockers; D012333:RNA, Messenger; D049994:Sodium Potassium Chloride Symporter Inhibitors; D028021:Sodium-Potassium-Chloride Symporters; D011189:Potassium Chloride