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Koukouritaki SB, Thinn AMM, Ashworth KJ, Fang J, Slater HS, Du LM, Nguyen HTT, Pillois X, Nurden AT, Ng CJ, Di Paola J, Zhu J, Wilcox DA. A single F153Sβ3 mutation causes constitutive integrin αIIbβ3 activation in a variant form of Glanzmann thrombasthenia. Blood Adv 2023; 7:3180-3191. [PMID: 36884296 PMCID: PMC10338211 DOI: 10.1182/bloodadvances.2022009495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 02/27/2023] [Accepted: 02/27/2023] [Indexed: 03/09/2023] Open
Abstract
This report identifies a novel variant form of the inherited bleeding disorder Glanzmann thrombasthenia, exhibiting only mild bleeding in a physically active individual. The platelets cannot aggregate ex vivo with physiologic agonists of activation, although microfluidic analysis with whole blood displays moderate ex vivo platelet adhesion and aggregation consistent with mild bleeding. Immunocytometry shows reduced expression of αIIbβ3 on quiescent platelets that spontaneously bind/store fibrinogen, and activation-dependent antibodies (ligand-induced binding site-319.4 and PAC-1) report β3 extension suggesting an intrinsic activation phenotype. Genetic analysis reveals a single F153Sβ3 substitution within the βI-domain from a heterozygous T556C nucleotide substitution of ITGB3 exon 4 in conjunction with a previously reported IVS5(+1)G>A splice site mutation with undetectable platelet messenger RNA accounting for hemizygous expression of S153β3. F153 is completely conserved among β3 of several species and all human β-integrin subunits suggesting that it may play a vital role in integrin structure/function. Mutagenesis of αIIb-F153Sβ3 also displays reduced levels of a constitutively activated αIIb-S153β3 on HEK293T cells. The overall structural analysis suggests that a bulky aromatic, nonpolar amino acid (F,W)153β3 is critical for maintaining the resting conformation of α2- and α1-helices of the βI-domain because small amino acid substitutions (S,A) facilitate an unhindered inward movement of the α2- and α1-helices of the βI-domain toward the constitutively active αIIbβ3 conformation, while a bulky aromatic, polar amino acid (Y) hinders such movements and restrains αIIbβ3 activation. The data collectively demonstrate that disruption of F153β3 can significantly alter normal integrin/platelet function, although reduced expression of αIIb-S153β3 may be compensated by a hyperactive conformation that promotes viable hemostasis.
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Affiliation(s)
- Sevasti B. Koukouritaki
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI
- Children’s Research Institute, Children’s Wisconsin, Milwaukee, WI
| | - Aye Myat M. Thinn
- Versiti Blood Research Institute, Milwaukee, WI
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI
| | - Katrina J. Ashworth
- Department of Pediatrics, Division of Hematology & Oncology, Washington University School of Medicine, Washington University in St. Louis, St. Louis, MO
| | - Juan Fang
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI
- Children’s Research Institute, Children’s Wisconsin, Milwaukee, WI
| | - Haley S. Slater
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI
- Children’s Research Institute, Children’s Wisconsin, Milwaukee, WI
| | - Lily M. Du
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI
- Children’s Research Institute, Children’s Wisconsin, Milwaukee, WI
| | | | - Xavier Pillois
- Xavier Arnozan Hôpital, Institut de Rythmologie et de Modélisation Cardiaque, Pessac, France
| | - Alan T. Nurden
- Xavier Arnozan Hôpital, Institut de Rythmologie et de Modélisation Cardiaque, Pessac, France
| | - Christopher J. Ng
- Department of Pediatrics, Section of Hematology/Oncology/Bone Marrow Transplant, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Jorge Di Paola
- Department of Pediatrics, Division of Hematology & Oncology, Washington University School of Medicine, Washington University in St. Louis, St. Louis, MO
| | - Jieqing Zhu
- Versiti Blood Research Institute, Milwaukee, WI
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI
| | - David A. Wilcox
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI
- Children’s Research Institute, Children’s Wisconsin, Milwaukee, WI
- Versiti Blood Research Institute, Milwaukee, WI
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