title: K+ channel antisense oligodeoxynucleotides inhibit cytokine-induced expansion of human hemopoietic progenitors.
abstract: Primitive human hemopoietic progenitor cells identified by surface membrane markers CD33-CD34+ are capable of expansion into lineage-restricted precursors following in vitro stimulation by hemopoietic regulators such as stem cell factor (SCF) and interleukin-3 (IL-3). In search of ionic currents involved in cytokine-induced progenitor cell growth and differentiation, human umbilical cord blood CD33-CD34+ cells were subjected to perforated patch-clamp recordings following overnight incubation with SCF and/or IL-3. An inward rectifying potassium channel (Kir) was found in 33% of control unstimulated cells, in 34% of cells incubated with IL-3, in 31% of cells incubated with SCF and in 75% of cells incubated with IL-3 plus SCF. Kir activity increased with elevation of extracellular potassium and was blocked by extracellular Cs+ or Ba2+ Antisense oligodeoxynucleotides directed against Kir blocked both mRNA and functional expression of Kir channels. Kir antisense also inhibited the in vitro expansion of cytokine-stimulated CD33-CD34+ cells into erythroid (BFU-E) and myeloid (GM-CFU) progenitors in 7-day suspension cultures. Extracellular Cs+ or Ba2+ induced a similar degree of inhibition (40-60%) of progenitor cell generation. These findings strongly suggest an essential role for Kir in the process of cytokine-induced primitive progenitor cell growth and differentiation.
authors.affiliation: Bruce Rappaport Faculty of Medicine, Dept. Biophysics and Physiology and Haemopoiesis Unit,Technion, Haifa, Israel.
authors.forename: O
authors.initials: O
authors.lastname: Shirihai
authors.forename: S
authors.initials: S
authors.lastname: Merchav
authors.forename: B
authors.initials: B
authors.lastname: Attali
authors.forename: D
authors.initials: D
authors.lastname: Dagan
mesh_terms: D015703:Antigens, CD / Q000032:analysis; D018952:Antigens, CD34 / Q000032:analysis; D015214:Antigens, Differentiation, Myelomonocytic / Q000032:analysis; D001483:Base Sequence; D002455:Cell Division / Q000276:immunology; D016207:Cytokines / Q000494:pharmacology*; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000276:immunology / Q000502:physiology*; D006801:Humans; D007473:Ion Channels / Q000037:antagonists & inhibitors; D008969:Molecular Sequence Data; D016376:Oligonucleotides, Antisense / Q000494:pharmacology*; D018408:Patch-Clamp Techniques; D015221:Potassium Channels / Q000737:chemistry / Q000502:physiology*; D063268:Sialic Acid Binding Ig-like Lectin 3
chemical_list: D015703:Antigens, CD; D018952:Antigens, CD34; D015214:Antigens, Differentiation, Myelomonocytic; C571163:CD33 protein, human; D016207:Cytokines; D007473:Ion Channels; D016376:Oligonucleotides, Antisense; D015221:Potassium Channels; D063268:Sialic Acid Binding Ig-like Lectin 3