Erythroid induction of K562 cells treated with mithramycin is associated with inhibition of raptor gene transcription and mammalian target of rapamycin complex 1 (mTORC1) functions

Finotti, Alessia; Bianchi, Nicoletta; Fabbri, Enrica; Borgatti, Monica; Breveglieri, Giulia; Gasparello, Jessica; Gambari, Roberto

doi:10.1016/j.phrs.2014.11.005

Cited by 28 publications

(35 citation statements)

References 55 publications

(84 reference statements)

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“…Rapamycin did not significantly affect GATA1 , GATA2 , and SCL mRNA expression at most time points. Interestingly, α ‐, β ‐, and γ ‐globin mRNA levels were increased in rapamycin‐treated cells, which was consistent with results obtained in other cell lines used as models for studying erythroid differentiation and in erythroid precursors from healthy animals and human subjects, and patients with β‐thalassemia 11‐13,15,18,23,24 . These results suggested that inhibition of mTOR signaling did not affect the process of erythropoiesis.…”

Section: Resultssupporting

confidence: 89%

The opposing roles of the mTOR signaling pathway in different phases of human umbilical cord blood-derived CD34+ cell erythropoiesis

et al. 2020

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As an indispensable, even lifesaving practice, red blood cell (RBC) transfusion is challenging due to several issues, including supply shortage, immune incompatibility, and blood‐borne infections since donated blood is the only source of RBCs. Although large‐scale in vitro production of functional RBCs from human stem cells is a promising alternative, so far, no such system has been reported to produce clinically transfusable RBCs due to the poor understanding of mechanisms of human erythropoiesis, which is essential for the optimization of in vitro erythrocyte generation system. We previously reported that inhibition of mammalian target of rapamycin (mTOR) signaling significantly decreased the percentage of erythroid progenitor cells in the bone marrow of wild‐type mice. In contrast, rapamycin treatment remarkably improved terminal maturation of erythroblasts and anemia in a mouse model of β‐thalassemia. In the present study, we investigated the effect of mTOR inhibition with rapamycin from different time points on human umbilical cord blood‐derived CD34+ cell erythropoiesis in vitro and the underlying mechanisms. Our data showed that rapamycin treatment significantly suppressed erythroid colony formation in the commitment/proliferation phase of erythropoiesis through inhibition of cell‐cycle progression and proliferation. In contrast, during the maturation phase of erythropoiesis, mTOR inhibition dramatically promoted enucleation and mitochondrial clearance by enhancing autophagy. Collectively, our results suggest contrasting roles for mTOR in regulating different phases of human erythropoiesis.

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Section: Resultssupporting

confidence: 89%

The opposing roles of the mTOR signaling pathway in different phases of human umbilical cord blood-derived CD34+ cell erythropoiesis

et al. 2020

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“…In our previous study (Kaneko et al 2012), no significant change was observed in the (P) RR expression levels during TGF-β-induced erythropoiesis in YN-1-0-A cells. Finotti et al (2015) reported that the inhibition of mammalian TOR complex 1 (mTORC1) functions by mithramycin caused an erythroid induction of K562 cells. Elevated expression levels of (P)RR during rapamycin-induced erythropoiesis in the present study may, therefore, be mediated by the inhibitory action of rapamycin on mTORC1.…”

Section: Discussionmentioning

confidence: 99%

Expression of (Pro)renin Receptor During Rapamycin-Induced Erythropoiesis in K562 Erythroleukemia Cells and Its Possible Dual Actions on Erythropoiesis

Kaneko

Ohba

Hirose

et al. 2017

Tohoku J. Exp. Med.

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(Pro)renin receptor ((P)RR), a specific receptor for renin and prorenin, is expressed in erythroblastic cells. (P)RR has multiple biological actions: prorenin activation, stimulation of the intracellular signaling including extracellular signal-regulated kinases, and functional complex formation with vacuolar H + -ATPase (v-ATPase). However, the functional implication of (P)RR in erythroblast cells has not been clarified. The aim of the present study was to clarify changes of (P)RR expression during erythropoiesis and a role of (P) RR in the heme synthesis. (P)RR expression was studied during rapamycin-induced erythropoiesis in a human erythroleukemia cell line, K562. Treatment with rapamycin (100 nM) for 48 hours significantly increased %number of hemoglobin-producing cells, γ -globin mRNA levels, erythroid specific 5-aminolevulinate synthase (ALAS2) mRNA levels, and heme content in K562 cells. Both (P)RR protein and mRNA levels increased about 1.4-fold during rapamycin-induced erythropoiesis. Suppression of (P) RR expression by (P)RR-specific small interference RNA increased ALAS2 mRNA levels about 1.6-fold in K562 cells, compared to control using scramble RNA, suggesting that (P)RR may down-regulate ALAS2 expression. By contrast, treatment with bafilomycin A1, an inhibitor of v-ATPase, decreased greatly % number of hemoglobin-producing cells and heme content in K562 cells, indicating that the v-ATPase function is essential for hemoglobinization and erythropoiesis. Treatment with bafilomycin A1 increased (P) RR protein and mRNA levels. In conclusion, we propose that (P)RR has dual actions on erythropoiesis: the promotion of erythropoiesis via v-ATPase function and the down-regulation of ALAS2 mRNA expression. Thus, (P)RR may contribute to the homeostatic control of erythropoiesis.

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“…The two-phase liquid culture procedure was employed as previously described [ 26 , 27 ]. The erythroid differentiation status of ErPCs was verified analyzing transferrin receptor (TrfR) and glycophorin A (GYPA) expression by FACS (fluorescence-activated cell sorting) using the BD FACScan™ system (Becton, Dickinson & Company, Franklin Lakes, NJ, USA) and anti-human CD71 (TrfR) FITC-conjugated antibody (Miltenyi Biotec GmbH, Bergisch Gladbach, Germany) and anti-human CD235a (GYPA) antibody PE-conjugated (Miltenyi Biotec GmbH) as described elsewhere [ 28 , 29 ]. Production of hemoglobins was assessed by high performance liquid chromatography (HPLC) as described elsewhere [ 11 , 28 ].…”

Section: Methodsmentioning

confidence: 99%

An Aγ-globin G->A gene polymorphism associated with β039 thalassemia globin gene and high fetal hemoglobin production

et al. 2017

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BackgroundIncrease of the expression of γ-globin gene and high production of fetal hemoglobin (HbF) in β-thalassemia patients is widely accepted as associated with a milder or even asymptomatic disease. The search for HbF-associated polymorphisms (such as the XmnI, BCL11A and MYB polymorphisms) has recently gained great attention, in order to stratify β-thalassemia patients with respect to expectancy of the first transfusion, need for annual intake of blood, response to HbF inducers (the most studied of which is hydroxyurea).MethodsAγ-globin gene sequencing was performed on genomic DNA isolated from a total of 75 β-thalassemia patients, including 31 β039/β039, 33 β039/β+IVSI-110, 9 β+IVSI-110/β+IVSI-110, one β0IVSI-1/β+IVSI-6 and one β039/β+IVSI-6.ResultsThe results show that the rs368698783 polymorphism is present in β-thalassemia patients in the 5’UTR sequence (+25) of the Aγ-globin gene, known to affect the LYAR (human homologue of mouse Ly-1 antibody reactive clone) binding site 5′-GGTTAT-3′. This Aγ(+25 G->A) polymorphism is associated with the Gγ-globin-XmnI polymorphism and both are linked with the β039-globin gene, but not with the β+IVSI-110-globin gene. In agreement with the expectation that this mutation alters the LYAR binding activity, we found that the Aγ(+25 G->A) and Gγ-globin-XmnI polymorphisms are associated with high HbF in erythroid precursor cells isolated from β039/β039 thalassemia patients.ConclusionsAs a potential explanation of our findings, we hypothesize that in β-thalassemia the Gγ-globin-XmnI/Aγ-globin-(G->A) genotype is frequently under genetic linkage with β0-thalassemia mutations, but not with the β+-thalassemia mutation here studied (i.e. β+IVSI-110) and that this genetic combination has been selected within the population of β0-thalassemia patients, due to functional association with high HbF. Here we describe the characterization of the rs368698783 (+25 G->A) polymorphism of the Aγ-globin gene associated in β039 thalassemia patients with high HbF in erythroid precursor cells.

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Erythroid induction of K562 cells treated with mithramycin is associated with inhibition of raptor gene transcription and mammalian target of rapamycin complex 1 (mTORC1) functions

Abstract: Graphical abstract

Cited by 28 publications

References 55 publications

The opposing roles of the mTOR signaling pathway in different phases of human umbilical cord blood-derived CD34+ cell erythropoiesis

The opposing roles of the mTOR signaling pathway in different phases of human umbilical cord blood-derived CD34+ cell erythropoiesis

Expression of (Pro)renin Receptor During Rapamycin-Induced Erythropoiesis in K562 Erythroleukemia Cells and Its Possible Dual Actions on Erythropoiesis

An Aγ-globin G->A gene polymorphism associated with β039 thalassemia globin gene and high fetal hemoglobin production

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