TY - JOUR
T1 - Novel variants in Krueppel like factor 1 that cause persistence of fetal hemoglobin in In(Lu) individuals
AU - Eernstman, Jesse
AU - Veldhuisen, Barbera
AU - Ligthart, Peter
AU - von Lindern, Marieke
AU - van der Schoot, C. Ellen
AU - van den Akker, Emile
N1 - Funding Information: We would like to thank Rob van Zwieten and Martijn Veldthuis (Sanquin, dept. Blood Cell Research) for the technical assistance and data acquisition regarding the HPLC data, and the Central Facility of Sanquin for their assistance regarding FCM analysis. This work was supported by grants from The Netherlands Organization for Health Research and Development (ZonMw-TOP, 40-00812-98-12128 to SH) and by Sanquin (PPOR:15-30; JE). Publisher Copyright: © 2021, The Author(s).
PY - 2021/12/1
Y1 - 2021/12/1
N2 - Beta-hemoglobinopathies become prominent after birth due to a switch from γ-globin to the mutated β-globin. Haploinsufficiency for the erythroid specific indispensable transcription factor Krueppel-like factor 1 (KLF1) is associated with high persistence of fetal hemoglobin (HPFH). The In(Lu) phenotype, characterized by low to undetectable Lutheran blood group expression is caused by mutations within KLF1 gene. Here we screened a blood donor cohort of 55 Lutheran weak or negative donors for KLF1 variants and evaluated their effect on KLF1 target gene expression. To discriminate between weak and negative Lutheran expression, a flow cytometry (FCM) assay was developed to detect Lu antigen expression. The Lu(a−b−) (negative) donor group, showing a significant decreased CD44 (Indian blood group) expression, also showed increased HbF and HbA2 levels, with one individual expressing HbF as high as 5%. KLF1 exons and promoter sequencing revealed variants in 80% of the Lutheran negative donors. Thirteen different variants plus one high frequency SNP (c.304 T > C) were identified of which 6 were novel. In primary erythroblasts, knockdown of endogenous KLF1 resulted in decreased CD44, Lu and increased HbF expression, while KLF1 over-expressing cells were comparable to wild type (WT). In line with the pleiotropic effects of KLF1 during erythropoiesis, distinct KLF1 mutants expressed in erythroblasts display different abilities to rescue CD44 and Lu expression and/or to affect fetal (HbF) or adult (HbA) hemoglobin expression. With this study we identified novel KLF1 variants to be include into blood group typing analysis. In addition, we provide further insights into the regulation of genes by KLF1.
AB - Beta-hemoglobinopathies become prominent after birth due to a switch from γ-globin to the mutated β-globin. Haploinsufficiency for the erythroid specific indispensable transcription factor Krueppel-like factor 1 (KLF1) is associated with high persistence of fetal hemoglobin (HPFH). The In(Lu) phenotype, characterized by low to undetectable Lutheran blood group expression is caused by mutations within KLF1 gene. Here we screened a blood donor cohort of 55 Lutheran weak or negative donors for KLF1 variants and evaluated their effect on KLF1 target gene expression. To discriminate between weak and negative Lutheran expression, a flow cytometry (FCM) assay was developed to detect Lu antigen expression. The Lu(a−b−) (negative) donor group, showing a significant decreased CD44 (Indian blood group) expression, also showed increased HbF and HbA2 levels, with one individual expressing HbF as high as 5%. KLF1 exons and promoter sequencing revealed variants in 80% of the Lutheran negative donors. Thirteen different variants plus one high frequency SNP (c.304 T > C) were identified of which 6 were novel. In primary erythroblasts, knockdown of endogenous KLF1 resulted in decreased CD44, Lu and increased HbF expression, while KLF1 over-expressing cells were comparable to wild type (WT). In line with the pleiotropic effects of KLF1 during erythropoiesis, distinct KLF1 mutants expressed in erythroblasts display different abilities to rescue CD44 and Lu expression and/or to affect fetal (HbF) or adult (HbA) hemoglobin expression. With this study we identified novel KLF1 variants to be include into blood group typing analysis. In addition, we provide further insights into the regulation of genes by KLF1.
UR - http://www.scopus.com/inward/record.url?scp=85115393309&partnerID=8YFLogxK
U2 - https://doi.org/10.1038/s41598-021-97149-y
DO - https://doi.org/10.1038/s41598-021-97149-y
M3 - Article
C2 - 34535703
SN - 2045-2322
VL - 11
JO - Scientific reports
JF - Scientific reports
IS - 1
M1 - 18557
ER -