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Bieker JJ, Philipsen S. Erythroid Krüppel-Like Factor (KLF1): A Surprisingly Versatile Regulator of Erythroid Differentiation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2024; 1459:217-242. [PMID: 39017846 DOI: 10.1007/978-3-031-62731-6_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/18/2024]
Abstract
Erythroid Krüppel-like factor (KLF1), first discovered in 1992, is an erythroid-restricted transcription factor (TF) that is essential for terminal differentiation of erythroid progenitors. At face value, KLF1 is a rather inconspicuous member of the 26-strong SP/KLF TF family. However, 30 years of research have revealed that KLF1 is a jack of all trades in the molecular control of erythropoiesis. Initially described as a one-trick pony required for high-level transcription of the adult HBB gene, we now know that it orchestrates the entire erythroid differentiation program. It does so not only as an activator but also as a repressor. In addition, KLF1 was the first TF shown to be directly involved in enhancer/promoter loop formation. KLF1 variants underlie a wide range of erythroid phenotypes in the human population, varying from very mild conditions such as hereditary persistence of fetal hemoglobin and the In(Lu) blood type in the case of haploinsufficiency, to much more serious non-spherocytic hemolytic anemias in the case of compound heterozygosity, to dominant congenital dyserythropoietic anemia type IV invariably caused by a de novo variant in a highly conserved amino acid in the KLF1 DNA-binding domain. In this chapter, we present an overview of the past and present of KLF1 research and discuss the significance of human KLF1 variants.
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Affiliation(s)
- James J Bieker
- Department of Cell, Developmental, and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
| | - Sjaak Philipsen
- Department of Cell Biology, Erasmus MC, Rotterdam, The Netherlands.
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Catapano R, Sessa R, Trombetti S, Cesaro E, Russo F, Izzo P, Makis A, Grosso M. Identification and Functional Analysis of Known and New Mutations in the Transcription Factor KLF1 Linked with β-Thalassemia-like Phenotypes. BIOLOGY 2023; 12:biology12040510. [PMID: 37106711 PMCID: PMC10135830 DOI: 10.3390/biology12040510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 03/16/2023] [Accepted: 03/24/2023] [Indexed: 03/31/2023]
Abstract
The erythroid transcriptional factor Krüppel-like factor 1 (KLF1) is a master regulator of erythropoiesis. Mutations that cause KLF1 haploinsufficiency have been linked to increased fetal hemoglobin (HbF) and hemoglobin A2 (HbA2) levels with ameliorative effects on the severity of β-thalassemia. With the aim of determining if KLF1 gene variations might play a role in the modulation of β-thalassemia, in this study we screened 17 subjects showing a β-thalassemia-like phenotype with a slight or marked increase in HbA2 and HbF levels. Overall, seven KLF1 gene variants were identified, of which two were novel. Functional studies were performed in K562 cells to clarify the pathogenic significance of these mutations. Our study confirmed the ameliorative effect on the thalassemia phenotype for some of these variants but also raised the notion that certain mutations may have deteriorating effects by increasing KLF1 expression levels or enhancing its transcriptional activity. Our results indicate that functional studies are required to evaluate the possible effects of KLF1 mutations, particularly in the case of the co-existence of two or more mutations that could differently contribute to KLF1 expression or transcriptional activity and consequently to the thalassemia phenotype.
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Affiliation(s)
- Rosa Catapano
- Department of Molecular Medicine and Medical Biotechnology, School of Medicine, University of Naples Federico II, 80131 Naples, Italy
| | - Raffaele Sessa
- Department of Molecular Medicine and Medical Biotechnology, School of Medicine, University of Naples Federico II, 80131 Naples, Italy
| | - Silvia Trombetti
- Department of Molecular Medicine and Medical Biotechnology, School of Medicine, University of Naples Federico II, 80131 Naples, Italy
- Department of Veterinary Medicine and Animal Productions, University of Naples Federico II, 80137 Naples, Italy
| | - Elena Cesaro
- Department of Molecular Medicine and Medical Biotechnology, School of Medicine, University of Naples Federico II, 80131 Naples, Italy
| | - Filippo Russo
- Department of Molecular Medicine and Medical Biotechnology, School of Medicine, University of Naples Federico II, 80131 Naples, Italy
| | - Paola Izzo
- Department of Molecular Medicine and Medical Biotechnology, School of Medicine, University of Naples Federico II, 80131 Naples, Italy
| | - Alexandros Makis
- Department of Pediatrics, University Hospital of Ioannina, Faculty of Medicine, School of Health Sciences, University of Ioannina, 45110 Ioannina, Greece
| | - Michela Grosso
- Department of Molecular Medicine and Medical Biotechnology, School of Medicine, University of Naples Federico II, 80131 Naples, Italy
- Correspondence:
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Moradi K, Alibakhshi R, Shafieenia S, Azimi A. Problem of borderline hemoglobin A2 levels in an Iranian population with a high prevalence of α- and β-thalassemia carriers. EGYPTIAN JOURNAL OF MEDICAL HUMAN GENETICS 2022. [DOI: 10.1186/s43042-022-00279-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
It is difficult to classify a small fraction of α- and β-thalassemia (α- and β-thal) carriers based on their Hb A2 levels. Here, we report the results of a molecular investigation in a cohort of thalassemia carriers with borderline Hb A2 levels originated from western Iran.
Results
The documents of 5956 α- or β-thal carriers were reviewed. The frequency of individuals with borderline Hb A2 levels in this cohort was 436 (7.32%). A total of 12 different α-thal and 27 different β-thal variants were identified in this study.
Conclusions
Our data showed that individuals with borderline Hb A2 are not uncommon in our population. Moreover, preselection of α- and β-thal carriers with borderline Hb A2 levels based on Hb A2, mean corpuscular volume (MCV), and mean cell hemoglobin (MCH) is not advisable in our population. Therefore, it is necessary to investigate both α- and β-globin genes in cases with borderline Hb A2 levels, especially if the partner is a carrier of β-thal or α0-thal.
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Tepakhan W, Kanjanaopas S, Srewaradachpisal K. Association Between Genetic Polymorphisms and Hb F Levels in Heterozygous β-Thalassemia 3.5 kb Deletions. Hemoglobin 2020; 44:338-343. [PMID: 32878504 DOI: 10.1080/03630269.2020.1811117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Single nucleotide polymorphisms (SNPs) in several genetic modifying factors have been related to Hb F levels, including Gγ XmnI polymorphism, B-cell lymphoma/leukemia 11 A (BCL11A), HBS1L-MYB intergenic polymorphism (HMIP) and a mutation in the Krüppel-like factor 1 (KLF1). This study aimed to determine whether genetic variability of these modifying factors affects Hb F levels in heterozygous β-thalassemia (β-thal) 3.5 kb deletion (NC_000011.10: g.5224302-5227791del13490bp). A total of 111 β-thal 3.5 kb deletion carriers with Hb F levels ranging from 0.9 to 18.4% was recruited for this study. Genotyping of SNPs including HBG2 rs7482144, HMIP rs4895441 and rs9399137, BCL11A rs4671393 and KLF1 rs2072596 was identified. Multiple regression analyses showed that only two SNPs (HMIP rs4895441 and rs9399137) influenced Hb F levels. Interestingly, a combination of these two SNPs was associated with higher Hb F levels. Our study is the first to demonstrate that the rs4895441, rs9399137 of HMIP are associated with elevated Hb F levels in the heterozygous β-thal 3.5 kb deletion.
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Affiliation(s)
- Wanicha Tepakhan
- Department of Pathology, Faculty of Medicine, Prince of Songkla University, Hat Yai, Songkhla, Thailand
| | - Sataron Kanjanaopas
- Department of Pathology, Faculty of Medicine, Prince of Songkla University, Hat Yai, Songkhla, Thailand
| | - Korntip Srewaradachpisal
- Department of Pathology, Faculty of Medicine, Prince of Songkla University, Hat Yai, Songkhla, Thailand
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Jiang H, Jiang F, Li J, Tang F, Li DZ. Congenital Nonspherocytic Hemolytic Anemia Caused by Krüppel-Like Factor 1 Gene Variants: Another Case Report. Hemoglobin 2019; 43:292-295. [PMID: 31645145 DOI: 10.1080/03630269.2019.1680384] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
In this study, we report on a compound heterozygote for variants in the key erythroid transcription factor Krüppel-like factor 1 (KLF1) gene in a patient who presented with severe, transfusion-dependent hemolytic anemia. The red cells were normochromic and normocytic, and resembled those seen in patients with congenital nonspherocytic hemolytic anemia (CNSHA). Next generation sequencing (NGS) revealed that the patient was a compound heterozygote for the KLF1 frameshift variant c.519_525dup (p.Gly176ArgfsTer179) and a missense variant c.1012C>A (p.Pro338Thr). This report adds to the wide clinical spectrum of KLF1 gene variants. We suggest that loss of KLF1 should be considered in otherwise unexplained cases of congenital hemolytic anemia.
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Affiliation(s)
- Hua Jiang
- Department of Pediatric Hematology-Oncology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, People's Republic of China
| | - Fan Jiang
- Prenatal Diagnostic Center, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, People's Republic of China
| | - Jian Li
- Prenatal Diagnostic Center, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, People's Republic of China
| | - Fang Tang
- Neonatal Screening Center, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, People's Republic of China
| | - Dong-Zhi Li
- Prenatal Diagnostic Center, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, People's Republic of China
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Nicolau M, Vargas S, Silva M, Coelho A, Ferreira E, Mendonça J, Vieira L, Kjöllerström P, Maia R, Silva R, Dias A, Ferreira T, Morais A, Soares IM, Lavinha J, Faustino P. Genetic modulators of fetal hemoglobin expression and ischemic stroke occurrence in African descendant children with sickle cell anemia. Ann Hematol 2019; 98:2673-2681. [PMID: 31478061 DOI: 10.1007/s00277-019-03783-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Accepted: 08/11/2019] [Indexed: 02/06/2023]
Abstract
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.
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Affiliation(s)
- Marta Nicolau
- Departamento de Genética Humana, Instituto Nacional de Saúde Dr. Ricardo Jorge, Lisbon, Portugal
| | - Sofia Vargas
- Departamento de Genética Humana, Instituto Nacional de Saúde Dr. Ricardo Jorge, Lisbon, Portugal
| | - Marisa Silva
- Departamento de Genética Humana, Instituto Nacional de Saúde Dr. Ricardo Jorge, Lisbon, Portugal
| | - Andreia Coelho
- Departamento de Genética Humana, Instituto Nacional de Saúde Dr. Ricardo Jorge, Lisbon, Portugal
| | - Emanuel Ferreira
- Departamento de Genética Humana, Instituto Nacional de Saúde Dr. Ricardo Jorge, Lisbon, Portugal
| | - Joana Mendonça
- Departamento de Genética Humana, Instituto Nacional de Saúde Dr. Ricardo Jorge, Lisbon, Portugal
| | - Luís Vieira
- Departamento de Genética Humana, Instituto Nacional de Saúde Dr. Ricardo Jorge, Lisbon, Portugal.,ToxOmics, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisbon, Portugal
| | - Paula Kjöllerström
- Unidade de Hematologia, Hospital de Dona Estefânia, Centro Hospitalar Universitário de Lisboa Central (CHULC), Lisbon, Portugal
| | - Raquel Maia
- Unidade de Hematologia, Hospital de Dona Estefânia, Centro Hospitalar Universitário de Lisboa Central (CHULC), Lisbon, Portugal
| | - Rita Silva
- Unidade de Neuropediatria, Hospital de Dona Estefânia, CHULC, Lisbon, Portugal
| | - Alexandra Dias
- Núcleo de Hematologia, Departamento de Pediatria, Hospital Prof. Doutor Fernando Fonseca, Amadora, Portugal
| | - Teresa Ferreira
- Núcleo de Hematologia, Departamento de Pediatria, Hospital Prof. Doutor Fernando Fonseca, Amadora, Portugal
| | - Anabela Morais
- Departamento de Pediatria, Hospital de Santa Maria, Centro Hospitalar Universitário de Lisboa Norte, Lisbon, Portugal
| | | | - João Lavinha
- Departamento de Genética Humana, Instituto Nacional de Saúde Dr. Ricardo Jorge, Lisbon, Portugal.,BioISI, Faculdade de Ciências, Universidade de Lisboa, Lisbon, Portugal
| | - Paula Faustino
- Departamento de Genética Humana, Instituto Nacional de Saúde Dr. Ricardo Jorge, Lisbon, Portugal. .,Instituto de Saúde Ambiental (ISAMB), Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal. .,Unidade de Investigação e Desenvolvimento, Departamento de Genética Humana, Instituto Nacional de Saúde Dr. Ricardo Jorge, Avenida Padre Cruz, 1649-016, Lisbon, Portugal.
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