title: Alteration of heme metabolism in a cellular model of Diamond-Blackfan anemia.
abstract: Diamond-Blackfan anemia (DBA) is a congenital pure red cell aplasia often associated with skeletal malformations. Mutations in ribosomal protein coding genes, mainly in RPS19, account for the majority of DBA cases. The molecular mechanisms underlying DBA pathogenesis are still not completely understood. Alternative spliced isoforms of FLVCR1 (feline leukemia virus subgroup C receptor 1) transcript coding for non-functional proteins have been reported in some DBA patients. Consistently, a phenotype very close to DBA has been described in animal models of FLVCR1 deficiency. FLVCR1 gene codes for two proteins: the plasma membrane heme exporter FLVCR1a and the mitochondrial heme exporter FLVCR1b. The coordinated expression of both FLVCR1 isoforms regulates an intracellular heme pool, necessary for proper expansion and differentiation of erythroid precursors. Here, we investigate the role of FLVCR1 isoforms in a cellular model of DBA. RPS19-downregulated TF1 cells show reduced FLVCR1a and FLVCR1b mRNA levels associated with heme overload. The downregulation of FLVCR1 isoforms affects cell cycle progression and apoptosis in differentiating K562 cells, a phenotype similar to DBA. Taken together, these data suggest that alteration of heme metabolism could play a role in the pathogenesis of DBA.
authors.affiliation: Department of Molecular Biotechnology and Health Sciences, Molecular Biotechnology Center, University of Torino, Torino, Italy.
authors.forename: Sonia
authors.initials: S
authors.lastname: Mercurio
authors.affiliation: Department of Health Sciences, University of Eastern Piedmont, Novara, Italy.
authors.forename: Anna
authors.initials: A
authors.lastname: Aspesi
authors.affiliation: Department of Molecular Biotechnology and Health Sciences, Molecular Biotechnology Center, University of Torino, Torino, Italy.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Silengo
authors.affiliation: Department of Molecular Biotechnology and Health Sciences, Molecular Biotechnology Center, University of Torino, Torino, Italy.
authors.forename: Fiorella
authors.initials: F
authors.lastname: Altruda
authors.affiliation: Department of Health Sciences, University of Eastern Piedmont, Novara, Italy.
authors.forename: Irma
authors.initials: I
authors.lastname: Dianzani
authors.affiliation: Department of Molecular Biotechnology and Health Sciences, Molecular Biotechnology Center, University of Torino, Torino, Italy.
authors.forename: Deborah
authors.initials: D
authors.lastname: Chiabrando
mesh_terms: D017398:Alternative Splicing; D029503:Anemia, Diamond-Blackfan / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D017209:Apoptosis; D002453:Cell Cycle; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000378:metabolism; D015973:Gene Expression Regulation, Leukemic; D006418:Heme / Q000819:agonists / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D006801:Humans; D020014:K562 Cells; D026901:Membrane Transport Proteins / Q000235:genetics* / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism; D008954:Models, Biological; D009154:Mutation; D020033:Protein Isoforms / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D011991:Receptors, Virus / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D012269:Ribosomal Proteins / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism
chemical_list: C492690:FLVCR1 protein, human; D026901:Membrane Transport Proteins; D020033:Protein Isoforms; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D011991:Receptors, Virus; D012269:Ribosomal Proteins; C040343:ribosomal protein S19; D006418:Heme
keywords: Diamond-Blackfan anemia; FLVCR1a; FLVCR1b; RPS19; heme