Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 1.225
Filtrar
1.
Gene ; 760: 145020, 2020 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-32755656

RESUMO

Conserved sequences across species have always provided valuable insights to improve our understanding on the human genome's entity and the interplay among different loci. Lymphoma/leukemia related factor (LRF) is encoded by ZBTB7A gene and belongs to an evolutionarily conserved family of transcription factors, implicated in vital cellular functions. The present data, demonstrating the wide-spread and the high overlap of the LRF/ZBTB7A recognition sites with genomic segments identified as CpG islands in the human genome, suggest that its binding capacity strongly depends on a specific sequence-encoded feature within CpGs. We have previously shown that de-methylation of the CpG island 326 lying in the ZBTB7A gene promoter is associated with impaired pharmacological induction of fetal hemoglobin in ß-type hemoglobinopathies patients. Within this context we aimed to investigate the extent of the LRF/ZBTB7A conservation among primates and mouse genome, focusing our interest also on the CpG island flanking the gene's promoter region, in an effort to further establish its epigenetic regulatory role in human hematopoiesis and pharmacological involvement in hematopoietic disorders. Comparative analysis of the human ZBTB7A nucleotide and amino acid sequences and orthologous sequences among non-human primates and mouse, exhibited high conservation scores. Pathway analysis, clearly indicated that LRF/ZBTB7A influences conserved cellular processes. These data in conjunction with the high levels of expression foremost in hematopoietic tissues, highlighted LRF/ZBTB7A as an essential factor operating indisputably during hematopoiesis.


Assuntos
Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Doenças Hematológicas/genética , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Animais , Sítios de Ligação/genética , Diferenciação Celular/genética , Linhagem Celular Tumoral , Sequência Conservada/genética , Ilhas de CpG/genética , Bases de Dados Genéticas , Hemoglobina Fetal/genética , Hematopoese/genética , Humanos , Camundongos , Primatas/genética , Regiões Promotoras Genéticas/genética
2.
Ann Hematol ; 99(7): 1475-1483, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32524201

RESUMO

Large deletions in the ß-globin gene cluster lead to increased HbF levels by delaying the γ- to ß-globin switch process. However, these deletions when inherited as a homozygous condition or when co-inherited with ß-thalassemia result in variable clinical phenotypes. Individuals or families with a clinically presenting child, where the parents had HbF levels ≥ 10%, were further screened for the presence of large ß-globin cluster deletions. Six deletions in the ß-globin gene cluster were screened by GAP-PCR, and the uncharacterized deletions were further analyzed by gene dosage or by multiplex ligation-dependent probe amplification (MLPA). Among 192 individuals suspected for the inheritance of large deletions, 138 were heterozygous for large deletions, 45 were compound heterozygous of a large ß-globin cluster deletion and ß-thalassemia, and 9 were found to be homozygous for deletions. Among the heterozygotes, the Asian Indian inversion-deletion was found to be the most common deletion (39.9%), followed by the HPFH-3 deletion (30.0%). Other deletions 49.3 kb, δß-thalassemia (21.2%), and 32.6 kb deletion (4.4%) were also found to be prevalent in our population. Patients compound heterozygous or homozygous for HPFH-3 and 32.6 kb deletions showed a milder clinical presentation, as compared with the patients compound heterozygous or homozygous for the Asian Indian inversion-deletion and 49.3 kb δß-thalassemia. This comprehensive study highlights the mutation spectrum of large ß-globin cluster deletions and the clinical heterogeneity in the patients homozygous or compound heterozygous with ß-thalassemia, thus asserting the need for molecular characterization of these deletions.


Assuntos
Hemoglobina Fetal/genética , Estudos de Associação Genética , Heterogeneidade Genética , Talassemia beta/epidemiologia , Talassemia beta/genética , Talassemia delta/epidemiologia , Talassemia delta/genética , Idade de Início , Criança , Mortalidade da Criança , Pré-Escolar , Feminino , Hemoglobina Fetal/análise , Estudos de Associação Genética/estatística & dados numéricos , Humanos , Índia/epidemiologia , Lactente , Padrões de Herança/genética , Masculino , Talassemia beta/sangue , Talassemia beta/mortalidade , Talassemia delta/sangue , Talassemia delta/mortalidade
3.
Ann Hematol ; 99(9): 2027-2036, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32567028

RESUMO

Increased expression of fetal hemoglobin (HbF) improves the clinical severity of ß-thalassemia patients. EHMT1/2 histone methyltransferases are epigenetic modifying enzymes that are responsible for catalyzing addition of the repressive histone mark H3K9me2 at silenced genes, including the γ-globin genes. UNC0638, a chemical inhibitor of EHMT1/2, has been shown to induce HbF expression in human erythroid progenitor cell cultures. Here, we report the HbF-inducing activity of UNC0638 in erythroid progenitor cells from ß-thalassemia/HbE patients. UNC0638 treatment led to significant increases in γ-globin mRNA, HbF expression, and HbF-containing cells in the absence of significant cytotoxicity. Moreover, UNC0638 showed additive effects on HbF induction in combination with the immunomodulatory drug pomalidomide and the DNMT1 inhibitor decitabine. These studies provide a scientific proof of concept that a small molecule targeting EHMT1/2 epigenetic enzymes, used alone or in combination with pomalidomide or decitabine, is a potential therapeutic approach for HbF induction. Further development of structural analogs of UNC0638 with similar biological effects but improved pharmacokinetic properties may lead to promising therapies and possible clinical application for the treatment of ß-thalassemia.


Assuntos
Células Precursoras Eritroides/metabolismo , Hemoglobina Fetal/biossíntese , Hemoglobina E/metabolismo , Quinazolinas/farmacologia , Talassemia beta/metabolismo , Proliferação de Células/efeitos dos fármacos , Proliferação de Células/fisiologia , Células Cultivadas , Relação Dose-Resposta a Droga , Células Precursoras Eritroides/efeitos dos fármacos , Hemoglobina Fetal/genética , Expressão Gênica , Humanos , Talassemia beta/genética
4.
Ann Hematol ; 99(7): 1453-1463, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32447424

RESUMO

Fetal hemoglobin (HbF) ameliorates clinical severity of sickle cell anemia (SCA). The major loci regulating HbF levels are HBB cluster, BCL11A, and HMIP-2 (HBS1L-MYB). However, the impact of noncoding single-nucleotide polymorphisms (SNPs) in these loci on clinical outcomes and their functional role on regulating HbF levels should be better elucidated. Therefore, we performed comprehensive association analyses of 14 noncoding SNPs in five loci with HbF levels and with clinical outcomes in a cohort of 250 children with SCA from Southeastern Brazil, and further performed functional annotation of these SNPs. We found SNPs independently associated with HbF levels: rs4671393 in BCL11A (ß-coefficient = 0.28), rs9399137 in HMIP-2A (ß-coefficient = 0.16), and rs4895441 in HMIP-2B (ß-coefficient = 0.15). Patients carrying minor (HbF-boosting) alleles for rs1427407, rs93979137, rs4895441, rs9402686, and rs9494145 showed reduced count of reticulocytes (p < 0.01), while those carrying the T allele of rs9494145 showed lower white blood cell count (p = 0.002). Carriers of the minor allele for rs9402686 showed higher peripheral saturation of oxygen (p = 0.002). Patients carrying minor alleles in BCL11A showed lower risk of transfusion incidence rate ratio (IRR ≥ 1.3; p < 0.0001). This effect was independent of HbF effect (p = 0.005). Carriers of minor alleles for rs9399137 and rs9402686 showed lower risk of acute chest syndrome (IRR > 1.3; p ≤ 0.01). Carriers of the reference allele for rs4671393 showed lower risk of infections (IRR = 1.16; p = 0.01). In conclusion, patients carrying HbF-boosting alleles of BCL11A and HMIP-2 were associated with milder clinical phenotypes. Higher HbF concentration may underlie this effect.


Assuntos
Anemia Falciforme/diagnóstico , Anemia Falciforme/genética , Hemoglobina Fetal/metabolismo , Proteínas de Ligação ao GTP/genética , Genes myb , Polimorfismo de Nucleotídeo Único , Proteínas Repressoras/genética , Alelos , Anemia Falciforme/sangue , Anemia Falciforme/epidemiologia , Brasil/epidemiologia , Criança , Pré-Escolar , Estudos de Coortes , Feminino , Hemoglobina Fetal/genética , Predisposição Genética para Doença , Estudo de Associação Genômica Ampla , Humanos , Lactente , Recém-Nascido , Masculino , Prognóstico , Estudos Retrospectivos
5.
Ann Hematol ; 99(5): 925-935, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32157419

RESUMO

Sickle cell disease (SCD) is an autosomal recessive blood disorder which occurs due to point mutation in the ß-globin chain of hemoglobin. Since the past decades, various therapies have been put forth, which are based on obstructing pathophysiological mechanisms of SCD including inhibition of Gardos channel and cation fluxes which in turn prevents sickle erythrocyte destruction and dehydration. The pharmacological approaches are based on the mechanism of reactivating γ-globin expression by utilizing fetal hemoglobin (HbF)-inducing drugs such as hydroxyurea. In SCD, gene therapy could be considered as a promising tool which involves modifying mutation at the gene-specific target by either promoting insertion or deletion of globins. Although there are various therapies emerged so far in the treatment of SCD, many of them have faced a major setback in most of developing countries in terms of cost, unavailability of expertise, and suitable donor. Therefore, in addition to pathophysiological aspects, this review will discuss new advancements and approaches made in the therapeutic domain of SCD including a viewpoint of modulating hemoglobin in SCD by the intervention of probiotics.


Assuntos
Anemia Falciforme , Eritrócitos Anormais , Hemoglobina Fetal , Hidroxiureia/uso terapêutico , Canais de Potássio Ativados por Cálcio de Condutância Intermediária , Probióticos/uso terapêutico , Anemia Falciforme/tratamento farmacológico , Anemia Falciforme/genética , Anemia Falciforme/metabolismo , Anemia Falciforme/fisiopatologia , Eritrócitos Anormais/metabolismo , Eritrócitos Anormais/patologia , Hemoglobina Fetal/genética , Hemoglobina Fetal/metabolismo , Humanos , Canais de Potássio Ativados por Cálcio de Condutância Intermediária/genética , Canais de Potássio Ativados por Cálcio de Condutância Intermediária/metabolismo
6.
BMC Med Genet ; 21(1): 43, 2020 02 28.
Artigo em Inglês | MEDLINE | ID: mdl-32111191

RESUMO

BACKGROUND: Individuals with δß-thalassemia/HPFH and ß-thalassemia usually present with intermedia or thalassemia major. No large-scale survey on HPFH/δß-thalassemia in southern China has been reported to date. The purpose of this study was to examine the molecular epidemiology and hematologic characteristics of these disorders in Guangzhou, the largest city in Southern China, to offer advice for thalassemia screening programs and genetic counseling. METHODS: A total of 125,661 couples participated in pregestational thalassemia screening. 654 subjects with fetal hemoglobin (HbF) level ≥ 5% were selected for further investigation. Gap-PCR combined with Multiplex ligation dependent probe amplification (MLPA) was used to screen for ß-globin gene cluster deletions. Gene sequencing for the promoter region of HBG1 /HBG2 gene was performed for all those subjects. RESULTS: A total of 654 individuals had hemoglobin (HbF) levels≥5, and 0.12% of the couples were found to be heterozygous for HPFH/δß-thalassemia, including Chinese Gγ (Aγδß)0-thal, Southeast Asia HPFH (SEA-HPFH), Taiwanese deletion and Hb Lepore-Boston-Washington. The highest prevalence was observed in the Huadu district and the lowest in the Nansha district. Three cases were identified as carrying ß-globin gene cluster deletions, which had not been previously reported. Two at-risk couples (0.0015%) were required to receive prenatal diagnosis. We also found 55cases of nondeletional-HPFH (nd-HPFH), including 54 with Italian nd-HPFH and one with the Aγ-197C-T heterozygous state. It is difficult to discriminate between Chinese Gγ (Aγδß)0-thal and Italian nd-HPFH carriers using hemoglobin (Hb) analysis. CONCLUSIONS: This study is the first to describe the familial prevalence of HPFH/δß-thalassemia and the high-risk rate in Greater Guangzhou Area, and the findings will support the implementation of thalassemia screening for three common deletions by gap-PCR. We also presented a systematic description of genotype-phenotype relationships which will be useful for genetic counseling and prenatal diagnostic services for ß-thalassemia intermedia.


Assuntos
Hemoglobina Fetal/genética , Talassemia beta/epidemiologia , Talassemia beta/genética , Talassemia delta/epidemiologia , Talassemia delta/genética , Adulto , Grupo com Ancestrais do Continente Asiático/genética , China/epidemiologia , Cidades/epidemiologia , Família , Feminino , Hemoglobinas Anormais/genética , Humanos , Masculino , Pessoa de Meia-Idade , Epidemiologia Molecular , Prevalência , Adulto Jovem , Globinas beta/genética , Talassemia beta/sangue , Talassemia delta/sangue
7.
Ann Hematol ; 99(1): 23-29, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31776727

RESUMO

Hemoglobin (Hb) F has a modulatory effect on the clinical phenotype of ß-thalassemia disease. High expression of Hb F in Hb E-related disorders has been noted, but the mechanism is not well understood. We have examined the association of a novel SNP rs11759328 on ARHGAP 18 gene and other known modulators with a variability of Hb F in Hb E-related disorders. Genotyping of SNP rs11759328 (G/A) was performed based on high-resolution melting analysis. The rs11759328 (A allele) was shown to be significantly associated with Hb F levels (p < 0.05) in heterozygous and homozygous Hb E. High levels of Hb F in both heterozygous and homozygous Hb E were also found to be associated with SNPs in the study of other modifying genes including KLF 1 mutation, rs7482144 (Gγ-XmnI), rs4895441, rs9399137 of (HBS1L-MYB), and rs4671393 (BCL11A). Multivariate analysis showed that KLF1 mutation and SNP rs11759328 (GA) (ARHGAP18) modulated Hb F expression in heterozygous Hb E. For homozygous Hb E, this was found to be related to five modifying factors, i.e., KLF1 mutation, rs4895441 (GG), rs9399137 (CC), rs4671393 (AA), and rs4671393 (GA). These results indicate that a novel SNP rs11759328 is a genetically modifying factor associated with increased Hb F in Hb E disorder.


Assuntos
Hemoglobina Fetal/biossíntese , Proteínas Ativadoras de GTPase/genética , Regulação da Expressão Gênica , Hemoglobinúria/genética , Mutação , Polimorfismo de Nucleotídeo Único , Hemoglobina Fetal/genética , Proteínas Ativadoras de GTPase/metabolismo , Hemoglobina E/genética , Hemoglobina E/metabolismo , Hemoglobinúria/sangue , Humanos , Fatores de Transcrição Kruppel-Like/genética , Fatores de Transcrição Kruppel-Like/metabolismo , Tailândia
8.
J Clin Pathol ; 73(8): 511-513, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31879269

RESUMO

We describe a dominant ß-thalassaemia caused by a deletion of G at nucleotide position 364 in exon 3 of the ß-globin gene. The heterozygosity of this mutation was found in a 36-year-old Thai patient who had moderate hypochromic microcytic anaemia with haemolytic blood picture. Haemoglobin (Hb) analysis revealed relatively higher Hbs A2 (6.8%) and F (4.7%) as compared with those of ß0-thalassaemia (n=278) and ß+-thalassaemia (n=55) carriers in our series. Secondary structure prediction of the elongated ß-globin chain showed that the α-helix at the C-terminal is disrupted dramatically by the random coil and ß-sheet, which should result in a highly unstable ß-globin variant, undetectable in peripheral blood and a dominant clinical phenotypic feature.


Assuntos
Éxons/genética , Hemoglobina Fetal/metabolismo , Hemoglobina A2/metabolismo , Deleção de Sequência/genética , Globinas beta/genética , Talassemia beta/genética , Adulto , DNA/análise , Hemoglobina Fetal/genética , Mutação da Fase de Leitura/genética , Hemoglobina A2/genética , Heterozigoto , Humanos , Masculino , Estrutura Secundária de Proteína/genética , Globinas beta/química
9.
Indian J Med Res ; 150(2): 161-166, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31670271

RESUMO

Background & objectives: Swiss-type hereditary persistence of foetal haemoglobin (HPFH) has been shown to be responsible for the wide range of F cell levels in healthy Thai adults. However, a survey for F cells in healthy Thai adults has not been performed. This study was conducted to determine the F cell distribution in adult Thai blood donors and to assess the possible involvement of ß-thalassaemia and haemoglobin E (HbE) carriers in increased HbF levels. Methods: Thai blood donors (n=375, 205 males and 170 females) were included in the study. Blood samples were collected for measuring haemoglobin (Hb) concentration and haematocrit (Hct) and F cell levels. Hb and Hct levels were determined by automated blood counter, while F cells were quantified by flow cytometric analysis of F cells stained by fluorescein isothiocyanate-conjugated anti γ-globin monoclonal antibody. Finally, F cell levels were compared between blood samples having mean corpuscular volume (MCV ) <80 fl and ≥80 fl as well as between ß-haemoglobinopathies (HbE and ß-thalassaemia carriers) and normal adults. Results: F cell levels varied markedly spanning 0.80-39.2 per cent with a positively skewed distribution. Thirty two per cent of these individuals had F cell levels more than the 4.5 per cent cut-off point. F cell levels in females were significantly higher than those in males (P<0.05). F cell levels in individuals having MCV <80 fl were significantly higher than those having MCV ≥80 fl (P<0.05). ß-haemoglobinopathy (HbE and ß-thalassaemia carriers) had significantly higher F cell levels than normal individuals (P<0.05). Interpretation & conclusions: The present results showed that besides Swiss-type HPFH, the ß-haemoglobinopathy was expected to be involved in increased F cell levels in adult Thais. Thus, influence of ß-haemoglobinopathy must be considered in interpreting F cell levels in area endemic of this globin disorder.


Assuntos
Hemoglobina Fetal/genética , Hemoglobina E/genética , Hemoglobinopatias/genética , Talassemia beta/genética , Adulto , Anemia Falciforme/sangue , Anemia Falciforme/epidemiologia , Anemia Falciforme/genética , Anemia Falciforme/patologia , Doadores de Sangue , Pré-Escolar , Índices de Eritrócitos/genética , Feminino , Hemoglobinopatias/sangue , Hemoglobinopatias/epidemiologia , Hemoglobinopatias/patologia , Heterozigoto , Humanos , Lactente , Recém-Nascido , Masculino , Fenótipo , Tailândia , Talassemia beta/sangue , Talassemia beta/epidemiologia , Talassemia beta/patologia
10.
Med Sci Monit ; 25: 7079-7086, 2019 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-31541070

RESUMO

BACKGROUND Higher fetal hemoglobin (HbF) levels can ameliorate the clinical severity of ß-thalassemia. The use of integrative strategies to combine results from gene microarray expression profiling, experimental evidence, and bioinformatics helps reveal functional long noncoding RNAs (lncRNAs) in ß-thalassemia and HbF induction. MATERIAL AND METHODS In a previous study, a microarray profiling was performed of 7 individuals with high HbF levels and 7 normal individuals. Thirteen paired samples were used for validation. lncRNA NR_001589 and uc002fcj.1 were chosen for further research. The quantitative reverse transcription-PCR was used to detect the expression levels of 2 lncRNAs. The Spearman correlation test was employed. The nuclear and cytoplasmic distribution experiment in K562 cells was used to verify the subcellular localization of 2 lncRNAs. Potential relationships among lncRNAs, predicted microRNAs (miRNAs), and target gene HBG1/2 were based on competitive endogenous RNA theory and bioinformatics analysis. RESULTS Average expression levels of NR_001589 and uc002fcj.1 were significantly higher in the high-HbF group than in the control group. A positive correlation existed between NR_001589, uc002fcj.1, and HbF. The expression of NR_001589 was in both the cytoplasm and the nucleus, mostly (77%) in the cytoplasm. The expression of uc002fcj.1 was in both the cytoplasm and the nucleus; the cytoplasmic proportion was 43% of the total amount. A triple lncRNA-miRNA-mRNA network was established. CONCLUSIONS Novel candidate genetic factors associated with the HBG1/2 expression were identified. Further functional investigation of NR_001589 and uc002fcj.1 can help deepen the understanding of molecular mechanisms in ß-thalassemia.


Assuntos
Hemoglobina Fetal/genética , RNA Longo não Codificante/genética , Talassemia beta/genética , Regulação da Expressão Gênica , Humanos , Células K562 , MicroRNAs/genética , MicroRNAs/metabolismo , RNA Longo não Codificante/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Reprodutibilidade dos Testes , Frações Subcelulares/metabolismo
11.
Ann Hematol ; 98(12): 2673-2681, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31478061

RESUMO

Sickle cell anemia (SCA) is an autosomal recessive monogenic disease with significant clinical variability. Cerebrovascular disease, particularly ischemic stroke, is one of the most severe complications of SCA in children. This study aimed to investigate the influence of genetic variants on the levels of fetal hemoglobin (Hb F) and biochemical parameters related with chronic hemolysis, as well as on ischemic stroke risk, in ninety-one unrelated SCA patients, children of sub-Saharan progenitors. Our results show that a higher Hb F level has an inverse relationship with the occurrence of stroke, since the group of patients who suffered stroke presents a significantly lower mean Hb F level (5.34 ± 4.57% versus 9.36 ± 6.48%; p = 0.024). Furthermore, the co-inheritance of alpha-thalassemia improves the chronic hemolytic pattern, evidenced by a decreased reticulocyte count (8.61 ± 3.58% versus 12.85 ± 4.71%; p < 0.001). In addition, our findings have confirmed the importance of HBG2 and BCL11A loci in the regulation of Hb F expression in sub-Saharan African SCA patients, as rs7482144_A, rs11886868_C, and rs4671393_A alleles are significantly associated with a considerable increase in Hb F levels (p = 0.019, p = 0.026, and p = 0.028, respectively). Concerning KLF1, twelve different variants were identified, two of them novel. Seventy-three patients (80.2%) presented at least one variant in this gene. However, no correlation was observed between the presence of these variants and Hb F level, severity of hemolysis, or stroke occurrence, which is consistent with their in silico-predicted minor functional consequences. Thus, we conclude that the prevalence of functional KLF1 variants in a sub-Saharan African background does not seem to be relevant to SCA clinical modulation.


Assuntos
Grupo com Ancestrais do Continente Africano , Anemia Falciforme , Isquemia Encefálica , Hemoglobina Fetal , Regulação da Expressão Gênica , Acidente Vascular Cerebral , Adolescente , Anemia Falciforme/complicações , Anemia Falciforme/etnologia , Anemia Falciforme/genética , Anemia Falciforme/metabolismo , Isquemia Encefálica/etnologia , Isquemia Encefálica/etiologia , Isquemia Encefálica/genética , Isquemia Encefálica/metabolismo , Criança , Pré-Escolar , Feminino , Hemoglobina Fetal/biossíntese , Hemoglobina Fetal/genética , Loci Gênicos , Humanos , Masculino , Acidente Vascular Cerebral/etnologia , Acidente Vascular Cerebral/etiologia , Acidente Vascular Cerebral/genética , Acidente Vascular Cerebral/metabolismo
12.
Yi Chuan ; 41(8): 669-676, 2019 Aug 20.
Artigo em Chinês | MEDLINE | ID: mdl-31447418

RESUMO

ß-thalassemia (ß-thal) is a fatal and disabling inherited blood disorder with diverse phenotypes. The same or similar genotype of ß-thal can manifest variable clinical severities. It is the hotspot and emphasis in the field of hematopathy and genetic diseases to explore genetic modifiers that influence the phenotype of ß-thal. This review illustrates the deteriorating and amelioratig modifiers from two aspects: genotypes of α-globin and quantitative trait locus of fetal hemoglobin (Hb F). Variations of transcription factors which reactive the γ-globin gene expression and ß-globin cluster cis-acting elements were introduced emphatically. Finally, clinical applications and future development prospects of ß-thal genetic modifiers are introduced by examples.


Assuntos
Talassemia beta/genética , Hemoglobina Fetal/genética , Genótipo , Humanos , Fenótipo , Fatores de Transcrição/genética , alfa-Globinas/genética , Globinas beta/genética , gama-Globinas/genética
13.
Ann Hematol ; 98(10): 2257-2265, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31440871

RESUMO

Vascular complications of sickle cell anemia (SCA) are influenced by many factors. Elevated plasma homocysteine (Hcy) is supposed to be an independent risk factor and is either genetic or nutritional origin. The present study evaluated the plasma Hcy level, MTHFR C677T gene polymorphism, effect of folic acid (FA) supplementation' and hemato-biochemical parameters in SCA and their effect on the vaso-occlusive crisis (VOC) in SCA patients of an Asian-Indian haplotype population. One hundred twenty cases of SCA (HbSS) and 50 controls with normal hemoglobin(HbAA) were studied. It was found that the plasma Hcy level is significantly higher (p < 0.0001) in patients with SCA (22.41 ± 7.8 µmol/L) compared to controls (13.2 ± 4.4 µmol/L). Moreover, patients without FA supplementation had a significantly (p < 0.001) higher Hcy level (27 ± 7 µmol/L) compared to those with supplementation (17.75 ± 5.7 µmol/L). Turkey-Kramer multiple comparison tests show that there is a significant difference (p < 0.05) in HbF percent, hemoglobin (Hb), platelet count, serum bilirubin (direct:Bil-D and total:Bil-T), aspartate transaminase (AST), lactate dehydrogenase (LDH), and plasma Hcy levels between mild and severe VOC. Between moderate VOC and severe VOC, there was a significant difference (p < 0.05) in HbF%, Bil-D, AST, Hcy. Pearson correlation revealed that plasma Hcy had a significantly (p < 0.05) positive correlation with AST, serum bilirubin (indirect and total), LDH, jaundice, stroke, VOC per year, and hospitalization per year whereas it was inversely correlated with HbF percentage, Hb level, and FA treatment. In the study population, increased plasma Hcy level, hemolysis, and platelet activation were found to influence VOC in SCA.


Assuntos
Anemia Falciforme , Homocisteína/sangue , Metilenotetra-Hidrofolato Redutase (NADPH2)/genética , Polimorfismo Genético , Doenças Vasculares , Adolescente , Adulto , Anemia Falciforme/sangue , Anemia Falciforme/complicações , Anemia Falciforme/genética , Anemia Falciforme/fisiopatologia , Aspartato Aminotransferases/sangue , Bilirrubina/sangue , Plaquetas/metabolismo , Feminino , Hemoglobina Fetal/genética , Hemoglobina Fetal/metabolismo , Hemólise , Homocisteína/genética , Humanos , L-Lactato Desidrogenase/sangue , Masculino , Metilenotetra-Hidrofolato Redutase (NADPH2)/sangue , Pessoa de Meia-Idade , Ativação Plaquetária , Contagem de Plaquetas , Doenças Vasculares/sangue , Doenças Vasculares/etiologia , Doenças Vasculares/genética , Doenças Vasculares/fisiopatologia
14.
Pharmacogenomics ; 20(11): 791-801, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31393228

RESUMO

Aim: ß-Type hemoglobinopathies are characterized by vast phenotypic diversity as far as disease severity is concerned, while differences have also been observed in hydroxyurea (HU) treatment efficacy. These differences are partly attributed to the residual expression of fetal hemoglobin (HbF) in adulthood. The Krüppel-like family of transcription factors (KLFs) are a set of zinc finger DNA-binding proteins which play a major role in HbF regulation. Here, we explored the possible association of variants in KLF gene family members with response to HU treatment efficacy and disease severity in ß-hemoglobinopathies patients. Materials & methods: Six tag single nucleotide polymorphisms, located in four KLF genes, namely KLF3, KLF4, KLF9 and KLF10, were analyzed in 110 ß-thalassemia major patients (TDT), 18 nontransfusion dependent ß-thalassemia patients (NTDT), 82 sickle cell disease/ß-thalassemia compound heterozygous patients and 85 healthy individuals as controls. Results: Our findings show that a KLF4 genomic variant (rs2236599) is associated with HU treatment efficacy in sickle cell disease/ß-thalassemia compound heterozygous patients and two KLF10 genomic variants (rs980112, rs3191333) are associated with persistent HbF levels in NTDT patients. Conclusion: Our findings provide evidence that genomic variants located in KLF10 gene may be considered as potential prognostic biomarkers of ß-thalassemia clinical severity and an additional variant in KLF4 gene as a pharmacogenomic biomarker, predicting response to HU treatment.


Assuntos
Anemia Falciforme/tratamento farmacológico , Fatores de Transcrição de Resposta de Crescimento Precoce/genética , Hemoglobinopatias/tratamento farmacológico , Fatores de Transcrição Kruppel-Like/genética , Talassemia beta/tratamento farmacológico , Anemia Falciforme/sangue , Anemia Falciforme/epidemiologia , Anemia Falciforme/genética , Biomarcadores Farmacológicos/metabolismo , Feminino , Hemoglobina Fetal/genética , Estudos de Associação Genética , Hemoglobinopatias/sangue , Hemoglobinopatias/epidemiologia , Hemoglobinopatias/genética , Humanos , Hidroxiureia/administração & dosagem , Hidroxiureia/efeitos adversos , Masculino , Polimorfismo de Nucleotídeo Único/genética , Índice de Gravidade de Doença , Resultado do Tratamento , Talassemia beta/sangue , Talassemia beta/epidemiologia , Talassemia beta/genética
15.
Blood ; 134(15): 1203-1213, 2019 10 10.
Artigo em Inglês | MEDLINE | ID: mdl-31467062

RESUMO

ß-Thalassemia and sickle cell disease (SCD) are the most prevalent monogenic diseases. These disorders are caused by quantitative or qualitative defects in the production of adult hemoglobin. Gene therapy is a potential treatment option for patients lacking an allogenic compatible hematopoietic stem cell (HSC) donor. New-generation lentiviral vectors (LVs) carrying a ß-globin-like gene have revolutionized this field by allowing effective HSC transduction, with no evidence of genotoxicity to date. Several clinical trials with different types of vector are underway worldwide; the initial results are encouraging with regard to the sustained production of therapeutic hemoglobin, improved biological parameters, a lower transfusion requirement, and better quality of life. Long-term follow-up studies will confirm the safety of LV-based gene therapy. The optimization of patient conditioning, HSC harvesting, and HSC transduction has further improved the therapeutic potential of this approach. Novel LV-based strategies for reactivating endogenous fetal hemoglobin (HbF) are also promising, because elevated HbF levels can reduce the severity of both ß-thalassemia and SCD. Lastly, genome-editing approaches designed to correct the disease-causing mutation or reactivate HbF are currently under investigation. Here, we discuss the clinical outcomes of current LV-based gene addition trials and the promising advantages of novel alternative therapeutic strategies.


Assuntos
Hemoglobina Fetal/genética , Edição de Genes/métodos , Terapia Genética/métodos , Hemoglobinopatias/terapia , Globinas beta/genética , Anemia Falciforme/genética , Anemia Falciforme/terapia , Animais , Ensaios Clínicos como Assunto , Terapia Genética/efeitos adversos , Vetores Genéticos/genética , Vetores Genéticos/uso terapêutico , Hemoglobinopatias/genética , Humanos , Lentivirus/genética , Talassemia beta/genética , Talassemia beta/terapia
16.
Anal Bioanal Chem ; 411(29): 7669-7680, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31273412

RESUMO

There is a general agreement that pharmacologically mediated stimulation of human γ-globin gene expression and increase of production of fetal hemoglobin (HbF) is a potential therapeutic approach in the experimental therapy of ß-thalassemia and sickle cell anemia. Here, we report the development and characterization of cellular biosensors carrying enhanced green fluorescence protein (EGFP) and red fluorescence protein (RFP) genes under the control of the human γ-globin and ß-globin gene promoters, respectively; these dual-reporter cell lines are suitable to identify the induction ability of screened compounds on the transcription in erythroid cells of γ-globin and ß-globin genes by FACS with efficiency and reproducibility. Our experimental system allows to identify (a) HbF inducers stimulating to different extent the activity of the γ-globin gene promoter and (b) molecules that stimulate also the activity of the ß-globin gene promoter. A good correlation does exist between the results obtained by using the EGFP/RFP clones and experiments performed on erythroid precursor cells from ß-thalassemic patients, confirming that this experimental system can be employed for high-throughput screening (HTS) analysis. Finally, we have demonstrated that this dual-reporter cell line can be used for HTS in 384-well plate, in order to identify novel HbF inducers for the therapy of ß-thalassemia and sickle cell anemia. Graphical abstract.


Assuntos
Técnicas Biossensoriais , Diferenciação Celular/efeitos dos fármacos , Eritrócitos/efeitos dos fármacos , Ensaios de Triagem em Larga Escala/métodos , Regiões Promotoras Genéticas , Transcrição Genética , Globinas beta/genética , gama-Globinas/genética , Eritrócitos/citologia , Hemoglobina Fetal/genética , Proteínas de Fluorescência Verde/genética , Humanos , Células K562 , Reprodutibilidade dos Testes
17.
Pediatr Blood Cancer ; 66(10): e27934, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31322815

RESUMO

BACKGROUND: Our objective was to investigate the combined and differential effects of alpha-thalassemia -3.7 kb deletion and HbF-promoting quantitative trait loci (HbF-QTL) in Senegalese hydroxyurea (HU)-free children and young adults with sickle cell anemia (SCA). PROCEDURE: Steady-state biological parameters and vaso-occlusive crises (VOC) requiring emergency admission were recorded over a 2-year period in 301 children with SCA. The age of the first hospitalized VOC was also recorded. These data were correlated with the alpha-globin and HbF-QTL genotypes. For the latter, three different genetic loci were studied (XmnI, rs7482144; BCL11A, rs1427407; and the HBS1L-MYB region, rs28384513) and a composite score was calculated, ranging from zero (none of these three polymorphisms) to six (all three polymorphisms at the homozygous state). RESULTS: A positive clinical impact of the HbF-QTL score on VOC rate, HbF, leucocytes, and C-reactive protein levels was observed only for patients without alpha-thalassemia deletion. Conversely, combination of homozygous -3.7 kb deletion with three to six HbF-QTL was associated with a higher VOC rate. The age of the first hospitalized VOC was delayed for patients with one or two alpha-thalassemia deletions and at least two HbF-QTL. CONCLUSION: Alpha-thalassemia -3.7 kb deletion and HbF-QTL are modulating factors of SCA clinical severity that interact with each other. They should be studied and interpreted together and not separately, at least in HU-free children.


Assuntos
Anemia Falciforme/genética , Hemoglobina Fetal/genética , Talassemia alfa/genética , Criança , Feminino , Genótipo , Hemoglobina H/genética , Humanos , Masculino , Locos de Características Quantitativas , Senegal
18.
Blood Cells Mol Dis ; 79: 102345, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31351219

RESUMO

Pharmacologic induction of fetal hemoglobin (HbF) is an effective strategy for treating sickle cell disease (SCD) by ameliorating disease severity. Hydroxyurea is the only FDA-approved agent that induces HbF, but significant non-responders and requirement for frequent monitoring of blood counts for drug toxicity limit clinical usefulness. Therefore, we investigated a novel prodrug conjugate of butyric acid (BA) and δ-aminolevulinate (ALA) as a potential HbF inducing agent, using erythroid precursors and a preclinical ß-YAC mouse model. We observed significantly increased γ-globin gene transcription and HbF expression mediated by AN-233 in K562 cells. Moreover, AN-233 stimulated mild heme biosynthesis and inhibited expression of heme-regulated eIF2α kinase involved in silencing γ-globin expression. Studies using primary erythroid precursors generated from sickle peripheral blood mononuclear cells verified the ability of AN-233 to induce HbF, increase histone H3 and H4 acetylation levels at the γ-globin promoter and reduce erythroid precursor sickling by 50%. Subsequent drug treatment of ß-YAC transgenic mice confirmed HbF induction in vivo by AN-233 through an increase in the percentage of HbF positive red blood cells and HbF levels measured by flow cytometry. These data support the potential development of AN-233 for the treatment of SCD.


Assuntos
Anemia Falciforme/terapia , Células Precursoras Eritroides/metabolismo , Hemoglobina Fetal/efeitos dos fármacos , Ácidos Levulínicos/farmacologia , Pró-Fármacos/farmacologia , Animais , Hemoglobina Fetal/genética , Hemoglobina Fetal/metabolismo , Humanos , Células K562 , Ácidos Levulínicos/uso terapêutico , Camundongos , Camundongos Transgênicos , Ativação Transcricional , gama-Globinas/genética
19.
Nat Genet ; 51(7): 1149-1159, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31253978

RESUMO

Developmental silencing of fetal globins serves as both a paradigm of spatiotemporal gene regulation and an opportunity for therapeutic intervention of ß-hemoglobinopathy. The nucleosome remodeling and deacetylase (NuRD) chromatin complex participates in γ-globin repression. We used pooled CRISPR screening to disrupt NuRD protein coding sequences comprehensively in human adult erythroid precursors. Essential for fetal hemoglobin (HbF) control is a non-redundant subcomplex of NuRD protein family paralogs, whose composition we corroborated by affinity chromatography and proximity labeling mass spectrometry proteomics. Mapping top functional guide RNAs identified key protein interfaces where in-frame alleles resulted in loss-of-function due to destabilization or altered function of subunits. We ascertained mutations of CHD4 that dissociate its requirement for cell fitness from HbF repression in both primary human erythroid precursors and transgenic mice. Finally we demonstrated that sequestering CHD4 from NuRD phenocopied these mutations. These results indicate a generalizable approach to discover protein complex features amenable to rational biochemical targeting.


Assuntos
Cromatina/genética , Células Eritroides/metabolismo , Hemoglobina Fetal/metabolismo , Regulação da Expressão Gênica , Complexo Mi-2 de Remodelação de Nucleossomo e Desacetilase/metabolismo , Mutagênese , Animais , Cromatina/metabolismo , Células Eritroides/citologia , Hemoglobina Fetal/genética , Humanos , Complexo Mi-2 de Remodelação de Nucleossomo e Desacetilase/genética , Camundongos , Camundongos Transgênicos , Domínios e Motivos de Interação entre Proteínas
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA