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1.
Heliyon ; 9(12): e22486, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38125408

RESUMO

This paper introduces a new trading strategy in investment: including the asset (Asset A) with the highest mean, the asset (Asset B) that stochastically dominates many other assets, and the asset (Asset C) with the smallest standard deviation in their portfolio to form portfolios in the efficient frontier for emerging and developed markets that could get higher expected utility and/or expected arbitrage opportunities. To test whether our proposed new trading strategy performs better, we set a few conjectures including the conjectures that investors should include any one, two, or three of Assets A, B, and C from emerging and developed markets. We test whether the conjectures hold by employing both mean-variance and stochastic dominance (SD) approaches to examine the performance of the portfolio formed by using hedge funds from emerging and developed markets with and without Assets A, B, and C, the naïve 1/N portfolio, and all other assets studied in our paper. We find that most of the portfolios with assets A, B, and C++ stochastically dominate the corresponding portfolio without any one, two, or all three of the A, B, and C strategies and dominate most, if not all, of the individual assets and the naïve 1/N portfolio in the emerging and developed markets, implying the existence of expected arbitrage opportunities in either emerging or developed markets and the market is inefficient. In addition, in this paper, we set a conjecture that combinations of portfolios with no arbitrage opportunity could generate portfolios that could have expected arbitrage opportunity. Our findings conclude that the conjecture holds and we claim that this phenomenon is a new anomaly in the financial market and our paper discovers a new anomaly in the financial market that expected arbitrage opportunity could be generated. We also conduct an out-of-sample analysis to check whether our proposed approach will work well in the out-of-sample period. Our findings also confirm our proposed new trading strategy to include Assets A, B, and C in the portfolio is the best strategy among all the other strategies used in our paper and gets the highest expected wealth and the highest expected utility for the emerging and developed markets. Our findings contribute to the literature on the emerging and developed markets of hedge funds and the reliability of alternative risk frameworks in the evaluation. Our findings also provide practical experience to academics, fund managers, and investors on how to choose assets in their portfolio to get significantly higher expected utility in emerging and developed markets.

2.
Pediatr Blood Cancer ; 70(1): e30067, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36250986

RESUMO

Unstable gamma globin variants can cause transient neonatal hemolytic anemia. We have identified a novel variant in a newborn who presented with jaundice and anemia requiring phototherapy and red blood cell transfusion. The patient was found to be heterozygous for the mutation HGB2:c.290T>C, p.Leu97Pro, which we have termed hemoglobin (Hb) Wareham. This substitution is expected to generate an unstable hemoglobin with increased oxygen affinity based on the homologous mutation previously described in the beta globin gene, which is termed as Hb Debrousse. The patient fully recovered by 9 months of age as expected with the transition from fetal to adult hemoglobin.


Assuntos
Anemia Hemolítica , Hemoglobinas Anormais , gama-Globinas , Humanos , Recém-Nascido , Anemia Hemolítica/genética , Globinas beta/genética , gama-Globinas/genética , Hemoglobinas Anormais/genética , Heterozigoto , Mutação , Lactente
3.
Br J Haematol ; 197(1): 97-109, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35118652

RESUMO

Sickle cell disease (SCD) is a genetic disorder that affects millions around the world. Enhancement of fetal γ-globin levels and fetal haemoglobin (HbF) production in SCD patients leads to diminished severity of many clinical features of the disease. We recently identified the transcriptional co-activator PGC-1α as a new protein involved in the regulation of the globin genes. Here, we report that upregulation of PGC-1α by infection with a lentivirus expressing PGC-1α or by the small-molecule PGC-1α agonist ZLN005 in human primary erythroid progenitor CD34+ cells induces both fetal γ-globin mRNA and protein expression as well as the percentage of HbF-positive cell (F cells) without significantly affecting cell proliferation and differentiation. We further found that the combination of ZLN005 and hydroxyurea (hydroxycarbamide) exhibited an additive effect on the expression of γ-globin and the generation of F cells from cultured CD34+ cells. In addition, ZLN005 induced robust expression of the murine embryonic ßh1-globin gene and to a lesser extent, human γ-globin gene expression in sickle mice. These findings suggest that activation of PGC-1α by ZLN005 might provide a new path for modulating HbF levels with potential therapeutic benefit in ß-hemoglobinopathies.


Assuntos
Anemia Falciforme , Hemoglobinopatias , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/metabolismo , Anemia Falciforme/tratamento farmacológico , Anemia Falciforme/genética , Animais , Hemoglobina Fetal/metabolismo , Expressão Gênica , Regulação da Expressão Gênica , Humanos , Camundongos , gama-Globinas/genética
6.
Hemoglobin ; 45(3): 212-214, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-34167424

RESUMO

We report a novel frameshift ß-thalassemia (ß-thal) mutation due to a two-nucleotide deletion at codon 118 of the ß-globin gene (HBB: c.356_357delTT) in a 4-year-old Iraqi Kurd female presenting as transfusion-dependent ß-thal. This frameshift mutation, unlike many others involving the third exon, behaved as a recessive ß0 defect and not as dominant ß-thal mutation.


Assuntos
Globinas beta , Talassemia beta , Pré-Escolar , Códon , Feminino , Mutação da Fase de Leitura , Humanos , Iraque , Globinas beta/genética , Talassemia beta/diagnóstico , Talassemia beta/etnologia , Talassemia beta/genética
7.
Clin Case Rep ; 9(1): 291-293, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33489176

RESUMO

This case report highlights the importance for health care providers to be aware of the αlpha-thalassemia syndromes, their relevance to clinical care and family counseling, appropriate diagnostic algorithm for definitive diagnosis.

9.
Nucleic Acids Res ; 49(D1): D1192-D1196, 2021 01 08.
Artigo em Inglês | MEDLINE | ID: mdl-33125055

RESUMO

HbVar (http://globin.bx.psu.edu/hbvar) is a widely-used locus-specific database (LSDB) launched 20 years ago by a multi-center academic effort to provide timely information on the numerous genomic variants leading to hemoglobin variants and all types of thalassemia and hemoglobinopathies. Here, we report several advances for the database. We made clinically relevant updates of HbVar, implemented as additional querying options in the HbVar query page, allowing the user to explore the clinical phenotype of compound heterozygous patients. We also made significant improvements to the HbVar front page, making comparative data querying, analysis and output more user-friendly. We continued to expand and enrich the regular data content, involving 1820 variants, 230 of which are new entries. We also increased the querying potential and expanded the usefulness of HbVar database in the clinical setting. These several additions, expansions and updates should improve the utility of HbVar both for the globin research community and in a clinical setting.


Assuntos
Bases de Dados Genéticas , Hemoglobinas/genética , Mutação , Software , Talassemia/genética , Expressão Gênica , Loci Gênicos , Genoma Humano , Genômica/métodos , Genótipo , Hemoglobinas/química , Hemoglobinas/metabolismo , Heterozigoto , Humanos , Internet , Fenótipo , Talassemia/classificação , Talassemia/patologia
10.
Blood Adv ; 3(20): 2995-3001, 2019 10 22.
Artigo em Inglês | MEDLINE | ID: mdl-31648320

RESUMO

Fetal hemoglobin (HbF) expression is partially governed by the trans-acting quantitative trait loci BCL11A and MYB and a cis-acting locus linked to the HBB gene cluster. Our previous analysis of the Genotype-Tissue Expression database suggested that BCL2L1 was associated with HbF gene expression. In erythroid progenitors from patients with sickle cell disease, BCL2L1 messenger RNA (mRNA) levels were positively correlated with HBG mRNA and total HbF concentration (r2 = 0.72, P = .047 and r2 = 0.68, P = .01, respectively). Inhibition of BCL2L1 protein activity in HbF-expressing HUDEP-1 cells decreased HBG expression in a dose-dependent manner. Overexpression of BCL2L1 in these cells increased HBG expression fourfold (P < .05) and increased F cells by 13% (P < .05). Overexpression of BCL2L1 in erythroid progenitors derived from primary adult CD34+ cells upregulated HBG expression 11-fold (P < .05), increased F cells by 18% (P < .01), did not significantly affect cell differentiation or proliferation, and had a minor effect on survival. Although the mechanism remains unknown, our results suggest that BCL2L1 is associated with HbF gene activation.


Assuntos
Regulação da Expressão Gênica , Proteína bcl-X/metabolismo , gama-Globinas/genética , Anemia Falciforme/genética , Antineoplásicos/farmacologia , Biomarcadores , Diferenciação Celular/genética , Linhagem Celular , Proliferação de Células/genética , Sobrevivência Celular/genética , Expressão Ectópica do Gene , Células Precursoras Eritroides/citologia , Células Precursoras Eritroides/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Células-Tronco Hematopoéticas/metabolismo , Humanos , Proteína bcl-X/antagonistas & inibidores
14.
Blood ; 133(21): 2255-2262, 2019 05 23.
Artigo em Inglês | MEDLINE | ID: mdl-30704988

RESUMO

The thalassemias are compelling targets for therapeutic genome editing in part because monoallelic correction of a subset of hematopoietic stem cells (HSCs) would be sufficient for enduring disease amelioration. A primary challenge is the development of efficient repair strategies that are effective in HSCs. Here, we demonstrate that allelic disruption of aberrant splice sites, one of the major classes of thalassemia mutations, is a robust approach to restore gene function. We target the IVS1-110G>A mutation using Cas9 ribonucleoprotein (RNP) and the IVS2-654C>T mutation by Cas12a/Cpf1 RNP in primary CD34+ hematopoietic stem and progenitor cells (HSPCs) from ß-thalassemia patients. Each of these nuclease complexes achieves high efficiency and penetrance of therapeutic edits. Erythroid progeny of edited patient HSPCs show reversal of aberrant splicing and restoration of ß-globin expression. This strategy could enable correction of a substantial fraction of transfusion-dependent ß-thalassemia genotypes with currently available gene-editing technology.


Assuntos
Edição de Genes , Regulação da Expressão Gênica , Células-Tronco Hematopoéticas , Sítios de Splice de RNA , Splicing de RNA , Globinas beta , Talassemia beta , Sistemas CRISPR-Cas , Células-Tronco Hematopoéticas/metabolismo , Células-Tronco Hematopoéticas/patologia , Humanos , Mutação Puntual , Globinas beta/biossíntese , Globinas beta/genética , Talassemia beta/genética , Talassemia beta/metabolismo , Talassemia beta/terapia
15.
Int J Lab Hematol ; 41(1): 87-93, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30216683

RESUMO

INTRODUCTION: Fetal hemoglobin (HbF) is the major modifier for sickle cell disease (SCD) severity. HbF is modulated mainly by three major quantitative trait loci (QTL) on chromosomes 2, 6, and 11. METHODS: Five SNPs in the three QTLs (HBG2, rs7482144; BCL11A, rs1427407 and rs10189857; and HBS1L-MYB intergenic region, rs28384513 and rs9399137) were investigated by multiplex PCR and reverse hybridization, and their roles in HbF and clinical phenotype variability in Iraqi Kurds with SCD were assessed. RESULTS: HBG2 rs7482144 with minor allele frequency (MAF) of 0.133 was the most significant contributor to HbF variability, contributing 18.1%, followed by rs1427407 (MAF of 0.266) and rs9399137 (MAF of 0.137) at 14.3% and 8.8%, respectively. The other two SNPs were not significant contributors. Furthermore, when the cumulative numbers of minor alleles in the three contributing SNPs were assessed, HbF% and hemoglobin concentration increased with increasing number of minor alleles (P < 0.0005 and 0.001, respectively), while serum lactic dehydrogenase, reticulocytes, leukocytes, transfusion, and pain frequencies decreased (P = 0.003, 0.004, <0.0005, <0.0005, and 0.017, respectively). CONCLUSIONS: It was demonstrated that SNPs in all three major HbF QTLs contribute significantly to HbF and clinical variability in Iraqi Kurds with SCD and that the cumulative number of minor alleles at contributing SNPs may serve as a better predictor of such variability in this population.


Assuntos
Anemia Falciforme/genética , Hemoglobina Fetal/genética , Fenótipo , Polimorfismo de Nucleotídeo Único , Alelos , Proteínas de Transporte/genética , Humanos , Iraque/etnologia , Proteínas Nucleares/genética , Locos de Características Quantitativas , Proteínas Repressoras
16.
Blood Adv ; 2(15): 1998-2011, 2018 08 14.
Artigo em Inglês | MEDLINE | ID: mdl-30108108

RESUMO

Robust ß-globin expression in erythroid cells derived from induced pluripotent stem cells (iPSCs) increases the resolution with which red blood cell disorders such as sickle cell disease and ß thalassemia can be modeled in vitro. To better quantify efforts in augmenting ß-globin expression, we report the creation of a ß-globin reporter iPSC line that allows for the mapping of ß-globin expression throughout human erythropoietic development in real time at single-cell resolution. Coupling this tool with single-cell RNA sequencing (scRNAseq) identified features that distinguish ß-globin-expressing cells and allowed for the dissection of the developmental and maturational statuses of iPSC-derived erythroid lineage cells. Coexpression of embryonic, fetal, and adult globins in individual cells indicated that these cells correspond to a yolk sac erythromyeloid progenitor program of hematopoietic development, representing the onset of definitive erythropoiesis. Within this developmental program, scRNAseq analysis identified a gradient of erythroid maturation, with ß-globin-expressing cells showing increased maturation. Compared with other cells, ß-globin-expressing cells showed a reduction in transcripts coding for ribosomal proteins, increased expression of members of the ubiquitin-proteasome system recently identified to be involved in remodeling of the erythroid proteome, and upregulation of genes involved in the dynamic translational control of red blood cell maturation. These findings emphasize that definitively patterned iPSC-derived erythroblasts resemble their postnatal counterparts in terms of gene expression and essential biological processes, confirming their potential for disease modeling and regenerative medicine applications.


Assuntos
Eritroblastos/metabolismo , Eritropoese , Regulação da Expressão Gênica , Células-Tronco Pluripotentes Induzidas/metabolismo , Globinas beta/biossíntese , Linhagem Celular Transformada , Eritroblastos/citologia , Humanos , Células-Tronco Pluripotentes Induzidas/citologia
17.
Pediatr Blood Cancer ; 65(9): e27220, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29749692

RESUMO

Alpha thalassemia due to nondeletional mutations usually leads to more severe disease than that caused by deletional mutations. Devastating outcomes such as hydrops fetalis can occur with two nondeletional mutations, therefore warranting DNA-based workup for suspected carriers with subtle hematological abnormalities for family counseling purposes. We describe three cases with hemoglobin (Hb) Adana, a nondeletional alpha chain mutation, compounded with an alpha globin gene deletion resulting in thalassemia intermedia. We review the literature, draw genotype-phenotype correlations from published cases of Hb Adana, and propose that this correlation can be used by clinicians to help direct diagnostic studies and urge hematologists to thoroughly workup high-risk patients.


Assuntos
Hemoglobinas Anormais/genética , alfa-Globinas/genética , Talassemia alfa/genética , Pré-Escolar , Códon/genética , Feminino , Deleção de Genes , Estudos de Associação Genética , Aconselhamento Genético , Humanos , Hidropisia Fetal/etiologia , Hidropisia Fetal/genética , Masculino , Mutação Puntual , Deleção de Sequência
18.
Stem Cells ; 36(7): 1004-1019, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29569827

RESUMO

Induced pluripotent stem cells (iPSCs) stand to revolutionize the way we study human development, model disease, and eventually, treat patients. However, these cell sources produce progeny that retain embryonic and/or fetal characteristics. The failure to mature to definitive, adult-type cells is a major barrier for iPSC-based disease modeling and drug discovery. To directly address these concerns, we have developed a chemically defined, serum and feeder-free-directed differentiation platform to generate hematopoietic stem-progenitor cells (HSPCs) and resultant adult-type progeny from iPSCs. This system allows for strict control of signaling pathways over time through growth factor and/or small molecule modulation. Through direct comparison with our previously described protocol for the production of primitive wave hematopoietic cells, we demonstrate that induced HSPCs are enhanced for erythroid and myeloid colony forming potential, and strikingly, resultant erythroid-lineage cells display enhanced expression of adult ß globin indicating definitive pathway patterning. Using this system, we demonstrate the stage-specific roles of two key signaling pathways, Notch and the aryl hydrocarbon receptor (AHR), in the derivation of definitive hematopoietic cells. We illustrate the stage-specific necessity of Notch signaling in the emergence of hematopoietic progenitors and downstream definitive, adult-type erythroblasts. We also show that genetic or small molecule inhibition of the AHR results in the increased production of CD34+ CD45+ HSPCs while conversely, activation of the same receptor results in a block of hematopoietic cell emergence. Results presented here should have broad implications for hematopoietic stem cell transplantation and future clinical translation of iPSC-derived blood cells. Stem Cells 2018;36:1004-1019.


Assuntos
Hematopoese/fisiologia , Células-Tronco Pluripotentes Induzidas/metabolismo , Receptores de Hidrocarboneto Arílico/metabolismo , Receptores Notch/genética , Diferenciação Celular , Humanos , Transdução de Sinais
19.
J Pediatr Hematol Oncol ; 40(3): e145-e147, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29309373

RESUMO

ß thalassemia is characterized by a deficient production of functional ß-globin chains and a relative excess of α-globin chains. An extremely diverse clinical spectrum-asymptomatic to transfusion-dependent-is primarily due to homozygosity or compound heterozygosity for the very large number of ß-thalassemia-causing mutations, along with interacting mutations that affect the α-globin and γ-globin genes and their expression. We report a case of a 16-month-old boy who was initially diagnosed with iron deficiency anemia until he was later found to be homozygous for a severe ß-thalassemia genotype with a mild hematologic phenotype. This was likely as a result of his ability to produce high levels of fetal hemoglobin.


Assuntos
Talassemia beta , Anemia/genética , Hemoglobina Fetal/biossíntese , Genótipo , Homozigoto , Humanos , Lactente , Masculino , Mutação , Fenótipo , Talassemia beta/complicações , Talassemia beta/genética
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