title: Gene expression profiling of erythroblasts from refractory anaemia with ring sideroblasts (RARS) and effects of G-CSF.
abstract: Refractory anaemia with ring sideroblasts (RARS) is characterized by anaemia, erythroid apoptosis, cytochrome c release and mitochondrial ferritin accumulation. Granulocyte-colony-stimulating factor (G-CSF) inhibits the first three of these features in vitro and in vivo. To dissect the molecular mechanisms underlying the RARS phenotype and anti-apoptotic effects of G-CSF, erythroblasts generated from normal (NBM) and RARS marrow CD34(+) cells were cultured +/-G-CSF and subjected to gene expression analysis (GEP). Several erythropoiesis-associated genes that were deregulated in RARS CD34(+) cells showed normal expression in erythroblasts, underscoring the importance of differentiation-specific GEP. RARS erythroblasts showed a marked deregulation of several pathways including apoptosis, DNA damage repair, mitochondrial function and the JAK/Stat pathway. ABCB7, transporting iron from mitochondria to cytosol and associated with inherited ring sideroblast formation was severely suppressed and expression decreased with differentiation, while increasing in NBM cultures. The same pattern was observed for the mitochondrial integrity gene MFN2. Other downregulated key genes included STAT5B, HSPA5, FANCC and the negative apoptosis regulator MAP3K7. Methylation status of key downregulated genes was normal. The mitochondrial pathway including MFN2 was significantly modified by G-CSF, and several heat shock protein genes were upregulated, as evidence of anti-apoptotic protection of erythropoiesis. By contrast, G-CSF had no effect on iron-transport or erythropoiesis-associated genes.
authors.affiliation: Centre of Experimental Haematology, Department of Medicine (Huddinge), Karolinska Institute, Stockholm, Sweden.
authors.forename: Maryam
authors.initials: M
authors.lastname: Nikpour
authors.forename: Andrea
authors.initials: A
authors.lastname: Pellagatti
authors.forename: Anquan
authors.initials: A
authors.lastname: Liu
authors.forename: Mohsen
authors.initials: M
authors.lastname: Karimi
authors.forename: Luca
authors.initials: L
authors.lastname: Malcovati
authors.forename: Vladimir
authors.initials: V
authors.lastname: Gogvadze
authors.forename: Ann-Mari
authors.initials: AM
authors.lastname: Forsblom
authors.forename: James S
authors.initials: JS
authors.lastname: Wainscoat
authors.forename: Mario
authors.initials: M
authors.lastname: Cazzola
authors.forename: Boris
authors.initials: B
authors.lastname: Zhivotovsky
authors.forename: Alf
authors.initials: A
authors.lastname: Grandien
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Boultwood
authors.forename: Eva
authors.initials: E
authors.lastname: Hellström-Lindberg
mesh_terms: D000368:Aged; D000753:Anemia, Refractory / Q000378:metabolism*; D000756:Anemia, Sideroblastic / Q000378:metabolism*; D017209:Apoptosis / Q000235:genetics; D002454:Cell Differentiation / Q000235:genetics; D002470:Cell Survival / Q000235:genetics; D002478:Cells, Cultured; D000091342:Endoplasmic Reticulum Chaperone BiP; D004900:Erythroblasts / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D015672:Erythroid Precursor Cells / Q000473:pathology; D004920:Erythropoiesis / Q000235:genetics; D005260:Female; D020869:Gene Expression Profiling / Q000379:methods; D005786:Gene Expression Regulation; D016179:Granulocyte Colony-Stimulating Factor / Q000494:pharmacology*; D006801:Humans; D007501:Iron / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D008928:Mitochondria / Q000502:physiology; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D015398:Signal Transduction / Q000235:genetics
chemical_list: D000091342:Endoplasmic Reticulum Chaperone BiP; C000717247:HSPA5 protein, human; D016179:Granulocyte Colony-Stimulating Factor; D007501:Iron