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1.
Nat Commun ; 14(1): 23, 2023 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-36635268

RESUMO

Sickle cell disease (SCD) is a heritable disorder caused by ß-globin gene mutations. Induction of fetal γ-globin is an established therapeutic strategy. Recently, epigenetic modulators, including G9a inhibitors, have been proposed as therapeutic agents. However, the molecular mechanisms whereby these small molecules reactivate γ-globin remain unclear. Here we report the development of a highly selective and non-genotoxic G9a inhibitor, RK-701. RK-701 treatment induces fetal globin expression both in human erythroid cells and in mice. Using RK-701, we find that BGLT3 long non-coding RNA plays an essential role in γ-globin induction. RK-701 selectively upregulates BGLT3 by inhibiting the recruitment of two major γ-globin repressors in complex with G9a onto the BGLT3 gene locus through CHD4, a component of the NuRD complex. Remarkably, BGLT3 is indispensable for γ-globin induction by not only RK-701 but also hydroxyurea and other inducers. The universal role of BGLT3 in γ-globin induction suggests its importance in SCD treatment.


Assuntos
Anemia Falciforme , RNA Longo não Codificante , Camundongos , Humanos , Animais , RNA Longo não Codificante/genética , RNA Longo não Codificante/metabolismo , gama-Globinas/genética , Células Eritroides/metabolismo , Anemia Falciforme/tratamento farmacológico , Anemia Falciforme/genética , Anemia Falciforme/metabolismo , Expressão Gênica , Hemoglobina Fetal/genética , Hemoglobina Fetal/metabolismo
2.
Front Immunol ; 13: 1051647, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36420267

RESUMO

Infection caused by extracellular single-celled trypanosomes triggers a lethal chronic wasting disease in livestock and game animals. Through screening of 10 Trypanosoma evansi field isolates, exhibiting different levels of virulence in mice, the current study identifies an experimental disease model in which infection can last well over 100 days, mimicking the major features of chronic animal trypanosomosis. In this model, despite the well-controlled parasitemia, infection is hallmarked by severe trypanosomosis-associated pathology. An in-depth scRNA-seq analysis of the latter revealed the complexity of the spleen macrophage activation status, highlighting the crucial role of tissue resident macrophages (TRMs) in regulating splenic extramedullary erythropoiesis. These new data show that in the field of experimental trypanosomosis, macrophage activation profiles have so far been oversimplified into a bi-polar paradigm (M1 vs M2). Interestingly, TRMs exert a double-sided effect on erythroid cells. On one hand, these cells express an erythrophagocytosis associated signature. On another hand, TRMs show high levels of Vcam1 expression, known to support their interaction with hematopoietic stem and progenitor cells (HSPCs). During chronic infection, the latter exhibit upregulated expression of Klf1, E2f8, and Gfi1b genes, involved in erythroid differentiation and extramedullary erythropoiesis. This process gives rise to differentiation of stem cells to BFU-e/CFU-e, Pro E, and Baso E subpopulations. However, infection truncates progressing differentiation at the orthochromatic erythrocytes level, as demonstrated by scRNAseq and flow cytometry. As such, these cells are unable to pass to the reticulocyte stage, resulting in reduced number of mature circulating RBCs and the occurrence of chronic anemia. The physiological consequence of these events is the prolonged poor delivery of oxygen to various tissues, triggering lactic acid acidosis and the catabolic breakdown of muscle tissue, reminiscent of the wasting syndrome that is characteristic for the lethal stage of animal trypanosomosis.


Assuntos
Anemia , Trypanosoma , Tripanossomíase , Camundongos , Animais , Eritropoese/fisiologia , Células Eritroides/patologia , Anemia/etiologia , Tripanossomíase/metabolismo , Diferenciação Celular
3.
Genes (Basel) ; 13(10)2022 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-36292612

RESUMO

Gene editing (GE) is an efficient strategy for correcting genetic mutations in monogenic hereditary diseases, including ß-thalassemia. We have elsewhere reported that CRISPR-Cas9-based gene editing can be employed for the efficient correction of the ß039-thalassemia mutation. On the other hand, robust evidence demonstrates that the increased production of fetal hemoglobin (HbF) can be beneficial for patients with ß-thalassemia. The aim of our study was to verify whether the de novo production of adult hemoglobin (HbA) using CRISPR-Cas9 gene editing can be combined with HbF induction protocols. The gene editing of the ß039-globin mutation was obtained using a CRISPR-Cas9-based experimental strategy; the correction of the gene sequence and the transcription of the corrected gene were analyzed by allele-specific droplet digital PCR and RT-qPCR, respectively; the relative content of HbA and HbF was studied by high-performance liquid chromatography (HPLC) and Western blotting. For HbF induction, the repurposed drug rapamycin was used. The data obtained conclusively demonstrate that the maximal production of HbA and HbF is obtained in GE-corrected, rapamycin-induced erythroid progenitors isolated from ß039-thalassemia patients. In conclusion, GE and HbF induction might be used in combination in order to achieve the de novo production of HbA together with an increase in induced HbF.


Assuntos
Talassemia , Talassemia beta , Adulto , Humanos , Hemoglobina Fetal/genética , Hemoglobina Fetal/metabolismo , Edição de Genes/métodos , Talassemia beta/genética , Talassemia beta/terapia , Sistemas CRISPR-Cas/genética , Células Eritroides/metabolismo , Talassemia/genética , Sirolimo
4.
Toxicol Pathol ; 50(7): 881-882, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36062427

RESUMO

This session, held during the 41st Annual STP Symposium, focused on mechanisms of decreased erythropoiesis and erythroid cell injury. The speakers provided comprehensive overviews of physiologic and pathologic erythropoiesis, reviewed various mechanisms of erythroid cell injury, and shared innovative investigative research with the audience.


Assuntos
Eritropoese , Fator de Transcrição GATA1 , Eritropoese/fisiologia , Células Eritroides
5.
Dis Markers ; 2022: 1226697, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36065334

RESUMO

Erythropoiesis is a highly complex and sophisticated multistage process regulated by many transcription factors, as well as noncoding RNAs. Anthrax toxin receptor 1 (ANTXR1) is a type I transmembrane protein that binds the anthrax toxin ligands and mediates the entry of its toxic part into cells. It also functions as a receptor for the Protective antigen (PA) of anthrax toxin, and mediates the entry of Edema factor (EF) and Lethal factor (LF) into the cytoplasm of target cells and exerts their toxicity. Previous research has shown that ANTXR1 inhibits the expression of γ-globin during the differentiation of erythroid cells. However, the effect on erythropoiesis from a cellular perspective has not been fully determined. This study examined the role of ANTXR1 on erythropoiesis using K562 and HUDEP-2 cell lines as well as cord blood CD34+ cells. Our study has shown that overexpression of ANTXR1 can positively regulate erythrocyte proliferation, as well as inhibit GATA1 and ALAS2 expression, differentiation, and apoptosis in K562 cells and hematopoietic stem cells. ANTXR1 knockdown inhibited proliferation, promoted GATA1 and ALAS2 expression, accelerated erythrocyte differentiation and apoptosis, and promoted erythrocyte maturation. Our study also showed that ANTXR1 may regulate the proliferation and differentiation of hematopoietic cells, though the Wnt/ß-catenin pathway, which may help to establish a possible therapeutic target for the treatment of blood disorders.


Assuntos
Células Eritroides , Células-Tronco Hematopoéticas , Proteínas dos Microfilamentos , Receptores de Superfície Celular , Via de Sinalização Wnt , 5-Aminolevulinato Sintetase/metabolismo , Moléculas de Adesão Celular , Diferenciação Celular , Proliferação de Células , Células Eritroides/metabolismo , Células-Tronco Hematopoéticas/metabolismo , Humanos , Proteínas dos Microfilamentos/metabolismo , Receptores de Superfície Celular/metabolismo
6.
Nat Genet ; 54(9): 1417-1426, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35941187

RESUMO

The fetal-to-adult switch in hemoglobin production is a model of developmental gene control with relevance to the treatment of hemoglobinopathies. The expression of transcription factor BCL11A, which represses fetal ß-type globin (HBG) genes in adult erythroid cells, is predominantly controlled at the transcriptional level but the underlying mechanism is unclear. We identify HIC2 as a repressor of BCL11A transcription. HIC2 and BCL11A are reciprocally expressed during development. Forced expression of HIC2 in adult erythroid cells inhibits BCL11A transcription and induces HBG expression. HIC2 binds to erythroid BCL11A enhancers to reduce chromatin accessibility and binding of transcription factor GATA1, diminishing enhancer activity and enhancer-promoter contacts. DNA-binding and crystallography studies reveal direct steric hindrance as one mechanism by which HIC2 inhibits GATA1 binding at a critical BCL11A enhancer. Conversely, loss of HIC2 in fetal erythroblasts increases enhancer accessibility, GATA1 binding and BCL11A transcription. HIC2 emerges as an evolutionarily conserved regulator of hemoglobin switching via developmental control of BCL11A.


Assuntos
Hemoglobinas , Fatores de Transcrição Kruppel-Like , Proteínas Repressoras , Proteínas Supressoras de Tumor , Proteínas de Transporte/genética , Células Eritroides/metabolismo , Hemoglobinas/genética , Humanos , Fatores de Transcrição Kruppel-Like/metabolismo , Proteínas Repressoras/genética , Proteínas Repressoras/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Proteínas Supressoras de Tumor/metabolismo , Globinas beta/genética , Globinas beta/metabolismo , gama-Globinas/genética
7.
Genes (Basel) ; 13(8)2022 07 26.
Artigo em Inglês | MEDLINE | ID: mdl-35893070

RESUMO

CD71+ erythroid cells (CECs) were only known as erythrocyte progenitors not so long ago. In present times, however, they have been shown to be active players in immune regulation, especially in immunosuppression by the means of ROS, arginase-1 and arginase-2 production. Here, we uncover organ-of-origin differences in cytokine gene expression using NanoString and protein production using Bio-Plex between CECs from healthy human adult bone marrow and from human fetal liver parenchyma. Namely, healthy human adult bone marrow CECs both expressed and produced IFN-a, IL-1b, IL-8, IL-18 and MIF mRNA and protein, while human fetal liver parenchymaCECs expressed and produced IFN-a, IL15, IL18 and TNF-b mRNA and protein. We also detected TLR2 and TLR9 gene expression in both varieties of CECs and TLR1 and NOD2 gene expression in human fetal liver parenchymaCECs only. These observations suggest that there might be undiscovered roles in immune response for CECs.


Assuntos
Arginase , Medula Óssea , Adulto , Células Eritroides , Humanos , Fígado , RNA Mensageiro , Secretoma , Transcriptoma
8.
Int J Hematol ; 116(2): 174-181, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35776402

RESUMO

The hematopoietic transcription factor GATA1 induces heme accumulation during erythropoiesis by directly activating genes mediating heme biosynthesis. In addition to its canonical functions as a hemoglobin prosthetic group and enzyme cofactor, heme regulates gene expression in erythroid cells both transcriptionally and post-transcriptionally. Heme binding to the transcriptional repressor BACH1 triggers its proteolytic degradation. In heme-deficient cells, BACH1 accumulates and represses transcription of target genes, including α- and ß-like globin genes, preventing the accumulation of cytotoxic free globin chains. A recently described BACH1-independent mechanism of heme-dependent transcriptional regulation is associated with a DNA motif termed heme-regulated motif (HERM), which resides at the majority of loci harboring heme-regulated chromatin accessibility sites. Progress on these problems has led to a paradigm in which cell type-specific transcriptional mechanisms determine the expression of enzymes mediating the synthesis of small molecules, which generate feedback loops, converging upon the transcription factor itself and the genome. This marriage between transcription factors and the small molecules that they control is predicted to be a canonical attribute of regulatory networks governing cell state transitions such as differentiation in the hematopoietic system and more broadly.


Assuntos
Fatores de Transcrição de Zíper de Leucina Básica , Heme , Fatores de Transcrição de Zíper de Leucina Básica/genética , Células Eritroides , Globinas/metabolismo , Humanos , Fatores de Transcrição/metabolismo
9.
Cell Chem Biol ; 29(8): 1273-1287.e8, 2022 08 18.
Artigo em Inglês | MEDLINE | ID: mdl-35839780

RESUMO

Reactivation of fetal hemoglobin expression by the downregulation of BCL11A is a promising treatment for ß-hemoglobinopathies. A detailed understanding of BCL11A-mediated repression of γ-globin gene (HBG1/2) transcription is lacking, as studies to date used perturbations by shRNA or CRISPR-Cas9 gene editing. We leveraged the dTAG PROTAC degradation platform to acutely deplete BCL11A protein in erythroid cells and examined consequences by nascent transcriptomics, proteomics, chromatin accessibility, and histone profiling. Among 31 genes repressed by BCL11A, HBG1/2 and HBZ show the most abundant and progressive changes in transcription and chromatin accessibility upon BCL11A loss. Transcriptional changes at HBG1/2 were detected in <2 h. Robust HBG1/2 reactivation upon acute BCL11A depletion occurred without the loss of promoter 5-methylcytosine (5mC). Using targeted protein degradation, we establish a hierarchy of gene reactivation at BCL11A targets, in which nascent transcription is followed by increased chromatin accessibility, and both are uncoupled from promoter DNA methylation at the HBG1/2 loci.


Assuntos
Proteínas Nucleares , Proteoma , Proteínas de Transporte/metabolismo , Cromatina/genética , Cromatina/metabolismo , Células Eritroides/metabolismo , Proteínas Nucleares/metabolismo , Proteoma/metabolismo , Proteínas Repressoras/genética , Proteínas Repressoras/metabolismo , Fatores de Transcrição/metabolismo
10.
Exp Hematol ; 112-113: 9-14.e7, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35839944

RESUMO

The accumulation of unbound α-globin chains in red blood cells is a crucial pathophysiology of ß-thalassemia. IOX1 (5-carboxy-8-hydroxyquinoline) is a broad-spectrum 2-oxoglutarate (2OG)-dependent oxygenase inhibitor that can reduce α-globin mRNA expression in human cord blood erythroid progenitor cells. Therefore, IOX1 has been proposed as a potential compound for ß-thalassemia treatment through the decrease in α-globin chain synthesis. However, there is no empirical evidence regarding the consequences of IOX1 in ß-thalassemia. In this study, the therapeutic effects of IOX1 were investigated in ß0-thalassemia/hemoglobin E (HbE) erythroid progenitor cells during in vitro erythropoiesis. The results indicated that IOX1 had no impact on α-globin gene expression, but it led instead to significant decreases in γ-globin and fetal hemoglobin (HbF, α2γ2) production without affecting well-known globin regulators: KLF1, BCL11A, LRF, and GATA1. In addition, differential mRNA expression of several genes in the hypoxia response pathway revealed the induction of EGLN1, the PHD2-encoding gene, as a result of IOX1 treatment. These findings suggested that IOX1 fails to lower α-globin gene expression; on the contrary, it mediates γ-globin and HbF silencing in ß0-thalassemia/HbE erythroid progenitor cells. Because of the negative correlation of EGLN1 and γ-globin gene expression after IOX1 treatment, repurposing IOX1 to study the hypoxia response pathway and γ-globin regulation may provide beneficial information for ß-thalassemia.


Assuntos
Hemoglobina E , Talassemia , Talassemia beta , Adulto , Proteínas de Transporte/metabolismo , Células Eritroides/metabolismo , Células Precursoras Eritroides/metabolismo , Hemoglobina Fetal , Hemoglobina E/genética , Hemoglobina E/metabolismo , Humanos , Hipóxia/metabolismo , RNA Mensageiro/genética , Talassemia/metabolismo , alfa-Globinas/metabolismo , Talassemia beta/terapia , gama-Globinas/genética
11.
Xi Bao Yu Fen Zi Mian Yi Xue Za Zhi ; 38(6): 494-500, 2022 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-35732606

RESUMO

Objective To investigate the role of endothelial PAS domain-containing protein 1 (EPAS1) gene encoded hypoxia-inducible factor 2α (HIF-2α) in erythroid differentiation of K562 human erythroleukemia cells under hypoxic conditions. Methods K562 cells were treated with 40 µmol/L of hemin and 0.1 ng/mL of cytarabine for erythroid differentiation. After normoxic and hypoxic(50 mL/L O2) incubation, the ratio of CD235a+CD71+ cells was detected by flow cytometry. The percentage of hemoglobin-positive cells was detected by benzidine staining. The level of cell proliferation was detected by CCK-8 assay. The mRNA and protein levels of EPAS1, insulin receptor substrate 2 (IRS2) and γ-globin were detected by real-time quantitative PCR and Wester blot analysis. Besides, the changes in the erythroid differentiation of K562 cells were evaluated after knockdown of EPAS1. Results Hypoxia promoted the erythroid differentiation of K562 cells and upregulated the expression of EPAS1. After EPAS1 kncokdown, the ratio of CD235a+CD71+ cells and hemoglobin-positive cells decreased, and the expressions of IRS2 and γ-globin declined significantly. Conclusion Hypoxia can significantly up-regulate the expression of EPAS1 in K562 cells and promote the erythroid differentiation.


Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos , Diferenciação Celular , Hipóxia Celular , Células Eritroides , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Células Eritroides/citologia , Hemoglobinas , Humanos , Proteínas Substratos do Receptor de Insulina/genética , Células K562 , gama-Globinas/genética
12.
Int J Mol Sci ; 23(11)2022 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-35682828

RESUMO

Studies of the regulatory networks and signals controlling erythropoiesis have brought important insights in several research fields of biology and have been a rich source of discoveries with far-reaching implications beyond erythroid cells biology. The aim of this review is to highlight key recent discoveries and show how studies of erythroid cells bring forward novel concepts and refine current models related to genome and 3D chromatin organization, signaling and disease, with broad interest in life sciences.


Assuntos
Cromatina , Fatores de Transcrição , Cromatina/genética , Células Eritroides , Eritropoese/genética , Fatores de Transcrição/genética
13.
Blood ; 139(23): 3359-3360, 2022 06 09.
Artigo em Inglês | MEDLINE | ID: mdl-35679077
14.
Nat Immunol ; 23(7): 1109-1120, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35761081

RESUMO

Nonimmune cells can have immunomodulatory roles that contribute to healthy development. However, the molecular and cellular mechanisms underlying the immunomodulatory functions of erythroid cells during human ontogenesis remain elusive. Here, integrated, single-cell transcriptomic studies of erythroid cells from the human yolk sac, fetal liver, preterm umbilical cord blood (UCB), term UCB and adult bone marrow (BM) identified classical and immune subsets of erythroid precursors with divergent differentiation trajectories. Immune-erythroid cells were present from the yolk sac to the adult BM throughout human ontogenesis but failed to be generated in vitro from human embryonic stem cells. Compared with classical-erythroid precursors, these immune-erythroid cells possessed dual erythroid and immune regulatory networks, showed immunomodulatory functions and interacted more frequently with various innate and adaptive immune cells. Our findings provide important insights into the nature of immune-erythroid cells and their roles during development and diseases.


Assuntos
Células Precursoras Eritroides , Transcriptoma , Adulto , Diferenciação Celular/genética , Células Eritroides , Sangue Fetal , Humanos , Recém-Nascido , Saco Vitelino
15.
Nat Genet ; 54(6): 874-884, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35618846

RESUMO

The mechanisms by which the fetal-type ß-globin-like genes HBG1 and HBG2 are silenced in adult erythroid precursor cells remain a fundamental question in human biology and have therapeutic relevance to sickle cell disease and ß-thalassemia. Here, we identify via a CRISPR-Cas9 genetic screen two members of the NFI transcription factor family-NFIA and NFIX-as HBG1/2 repressors. NFIA and NFIX are expressed at elevated levels in adult erythroid cells compared with fetal cells, and function cooperatively to repress HBG1/2 in cultured cells and in human-to-mouse xenotransplants. Genomic profiling, genome editing and DNA binding assays demonstrate that the potent concerted activity of NFIA and NFIX is explained in part by their ability to stimulate the expression of BCL11A, a known silencer of the HBG1/2 genes, and in part by directly repressing the HBG1/2 genes. Thus, NFI factors emerge as versatile regulators of the fetal-to-adult switch in ß-globin production.


Assuntos
Hemoglobina Fetal , gama-Globinas , Animais , Proteínas de Transporte/genética , Células Eritroides/metabolismo , Hemoglobina Fetal/genética , Hemoglobina Fetal/metabolismo , Edição de Genes , Camundongos , Fatores de Transcrição NFI/genética , Fatores de Transcrição NFI/metabolismo , Fatores de Transcrição/genética , Globinas beta/genética , Globinas beta/metabolismo , gama-Globinas/genética , gama-Globinas/metabolismo
16.
Int J Hematol ; 116(2): 192-198, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35610497

RESUMO

Enucleation is a crucial event during the erythropoiesis, implicating drastic morphologic and transcriptomic/proteomic changes. While many genes deletion lead to failed or impaired enucleation have been identified, directly triggering the erythroid maturation, particularly enucleation, is still challenging. Inducing enucleation at the desired timing is necessary to develop efficient methods to generate mature, fully functional red blood cells in vitro for future transfusion therapies. However, there are considerable differences between primary erythroid cells and cultured cell sources, particularly pluripotent stem cell-derived erythroid cells and immortalized erythroid cell lines. For instance, the difference in the proliferative status between those cell types could be a critical factor, as cell cycle exit is closely connected to the terminal maturation of primary. In this review, we will discuss previous findings on the enucleation machinery and current challengings to trigger the enucleation of infinite erythroid cell sources.


Assuntos
Células-Tronco Pluripotentes , Proteômica , Diferenciação Celular/genética , Eritrócitos , Células Eritroides , Eritropoese/genética , Humanos
17.
J Toxicol Sci ; 47(4): 125-138, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35370240

RESUMO

Fetal rat anemia from flumioxazin, an N-phenylimide herbicide, is caused by suppression of heme synthesis resulting from inhibition of protoporphyrinogen oxidase (PPO). A series of studies to investigate the effects of flumioxazin have revealed that developmental toxicity is caused in rats but not in rabbits, and the adverse effects are not likely to occur in humans. In this study, as a final weight-of-evidence approach for assessing the human safety of flumioxazin, we compared the toxic potential of inhibition of heme synthesis leading to anemia between human and rat embryonic erythroid cells, which were degenerated as the target of flumioxazin in the rat developmental toxicity. To obtain embryonic erythroid cells, we established respective differentiation methods for embryonic erythroid cells from both human and rat pluripotent stem cells. Derived human and rat embryonic erythroid cells were treated with flumioxazin or dihydroartemisinin (DHA), an anti-malarial drug that causes reduction of embryonic erythroid cells and leads to anemia without species differences. In the human embryonic erythroid cells, DHA inhibited cell proliferation and heme synthesis, whereas there were no effects on heme content or cell proliferation with flumioxazin. In the rat embryonic erythroid cells, however, a dose-related reduction in heme synthesis occurred with treatment of flumioxazin and of DHA. These results confirmed that flumioxazin has no effect on heme synthesis in human embryonic erythroid cells. The present data were in accordance with the results of previous studies and demonstrated that there are no concerns in humans regarding the developmental toxicity of flumioxazin observed in rats.


Assuntos
Ftalimidas , Células-Tronco Pluripotentes , Animais , Benzoxazinas , Células Eritroides , Heme/toxicidade , Humanos , Ftalimidas/toxicidade , Coelhos , Ratos
18.
Front Immunol ; 13: 830025, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35251018

RESUMO

BACKGROUND: Immune suppression contributes to nosocomial infections (NIs) and poor prognosis in sepsis. Recent studies revealed that CD71+ erythroid cells had unappreciated immunosuppressive functions. This study aimed to investigate the values of CD71+ erythroid cells (CECs) in predicting NIs and prognosis among adult septic patients. The potential factors associated with the expansion of CECs were also explored. METHODS: In total, 112 septic patients and 32 critically ill controls were enrolled. The frequencies of CD71+ cells, CD71+CD235a+ cells, and CD45+ CECs were measured by flow cytometry. The associations between CECs and NIs and 30-day mortality were assessed by ROC curve analysis and Cox and competing-risk regression models. Factors associated with the frequency of CECs were identified by linear regression analysis. RESULTS: The percentage of CD71+ cells, CECs, and CD45+ CECs were higher in septic patients than critically ill controls. In septic patients, the percentages of CD71+ cells, CECs, and CD45+ CECs were associated with NI development, while CD71+ cells and CECs were independently associated with 30-day mortality. Linear regression analysis showed that the levels of interleukin (IL)-6 and interferon (IFN)-γ were positively associated with the frequencies of CD71+ cells, CECs, and CD45+ CECs, while IL-10 was negatively associated with them. Additionally, the levels of red blood cells (RBCs) were negatively associated with the percentage of CD45+ CECs. CONCLUSIONS: CECs were expanded in sepsis and can serve as independent predictors of the development of NI and 30-day mortality. Low levels of RBCs and high levels of IL-6 and IFN-γ may contribute to the expansion of CECs in sepsis. TRIAL REGISTRATION: ChiCTR, ChiCTR1900024887. Registered 2 August 2019, http://www.chictr.org.cn/showproj.aspx?proj=38645.


Assuntos
Infecção Hospitalar , Sepse , Adulto , Estado Terminal , Células Eritroides , Humanos , Prognóstico
19.
Blood ; 139(23): 3439-3449, 2022 06 09.
Artigo em Inglês | MEDLINE | ID: mdl-35349664

RESUMO

We follow a patient with Diamond-Blackfan anemia (DBA) mosaic for a pathogenic RPS19 haploinsufficiency mutation with persistent transfusion-dependent anemia. Her anemia remitted on eltrombopag (EPAG), but surprisingly, mosaicism was unchanged, suggesting that both mutant and normal cells responded. When EPAG was withheld, her anemia returned. In addition to expanding hematopoietic stem/progenitor cells, EPAG aggressively chelates iron. Because DBA anemia, at least in part, results from excessive intracellular heme leading to ferroptotic cell death, we hypothesized that the excess heme accumulating in ribosomal protein-deficient erythroid precursors inhibited the growth of adjacent genetically normal precursors, and that the efficacy of EPAG reflected its ability to chelate iron, limit heme synthesis, and thus limit toxicity in both mutant and normal cells. To test this, we studied Rpl11 haploinsufficient (DBA) mice and mice chimeric for the cytoplasmic heme export protein, FLVCR. Flvcr1-deleted mice have severe anemia, resembling DBA. Mice transplanted with ratios of DBA to wild-type marrow cells of 50:50 are anemic, like our DBA patient. In contrast, mice transplanted with Flvcr1-deleted (unable to export heme) and wild-type marrow cells at ratios of 50:50 or 80:20 have normal numbers of red cells. Additional studies suggest that heme exported from DBA erythroid cells might impede the nurse cell function of central macrophages of erythroblastic islands to impair the maturation of genetically normal coadherent erythroid cells. These findings have implications for the gene therapy of DBA and may provide insights into why del(5q) myelodysplastic syndrome patients are anemic despite being mosaic for chromosome 5q deletion and loss of RPS14.


Assuntos
Anemia de Diamond-Blackfan , Anemia , Anemia/patologia , Anemia de Diamond-Blackfan/metabolismo , Animais , Deleção Cromossômica , Células Eritroides/metabolismo , Eritropoese/genética , Feminino , Heme/metabolismo , Humanos , Ferro/metabolismo , Camundongos , Proteínas Ribossômicas/genética , Proteínas Ribossômicas/metabolismo
20.
J Cell Mol Med ; 26(8): 2404-2416, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35249258

RESUMO

Red blood cells (RBCs) generated ex vivo have the potential to be used for transfusion. Human embryonic stem cells (ES) and induced pluripotent stem cells (iPS) possess unlimited self-renewal capacity and are the preferred cell sources to be used for ex vivo RBC generation. However, their applications are hindered by the facts that the expansion of ES/iPS-derived erythroid cells is limited and the enucleation of ES/iPS-derived erythroblasts is low compared to that derived from cord blood (CB) or peripheral blood (PB). To address this, we sought to investigate the underlying mechanisms by comparing the in vitro erythropoiesis profiles of CB CD34+ and ES CD34+ cells. We found that the limited expansion of ES CD34+ cell-derived erythroid cells was associated with defective cell cycle of erythroid progenitors. In exploring the cellular and molecular mechanisms for the impaired enucleation of ES CD34+ cell-derived orthochromatic erythroblasts (ES-ortho), we found the chromatin of ES-ortho was less condensed than that of CB CD34+ cell-derived orthochromatic erythroblasts (CB-ortho). At the molecular level, both RNA-seq and ATAC-seq analyses revealed that pathways involved in chromatin modification were down-regulated in ES-ortho. Additionally, the expression levels of molecules known to play important role in chromatin condensation or/and enucleation were significantly lower in ES-ortho compared to that in CB-ortho. Together, our findings have uncovered mechanisms for the limited expansion and impaired enucleation of ES CD34+ cell-derived erythroid cells and may help to improve ex vivo RBC production from stem cells.


Assuntos
Eritropoese , Sangue Fetal , Antígenos CD34/metabolismo , Diferenciação Celular , Cromatina/metabolismo , Células-Tronco Embrionárias/metabolismo , Células Eritroides , Humanos
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