Thesis Boğaç Erçığ

Op 21 mei 2021 verdedigde Boğaç Erçığ zijn thesis 'A sweet touch on ADAMTS13: Insights into the pathophysiology of immune TTP'.

Promotoren: Prof JJ Voorberg PhD en prof K Vanhoorelbeke PhD
Copromotoren: Prof CPM Reutelingsperger PhD en GAF Nicolaes PhD
Locatie: Universiteit van Amsterdam, Agnietenkapel en online

Summary

Cover thesis Boğaç Erçığ

Thrombotic thrombocytopenic purpura is a rare, life-threatening disease which is portrayed by profound thrombocytopenia, microangiopathic hemolytic anemia and severe organ failures. TTP is classified as a thrombotic microangiopathy (TMA), and only ADAMTS13 deficiency distinguishes TTP from the rest of TMAs. ADAMTS13 deficiency is rarely caused by mutations in the ADAMTS13 gene (congenital TTP; cTTP) or commonly due to the development of anti-ADAMTS13 autoantibodies (immune-mediated TTP; iTTP). 
The main focus of this thesis is to improve the understanding on the structure and function of ADAMTS13 which provides novel insights on how the enzyme performs at molecular level to maintain hemostasis and to design novel therapeutic options for iTTP patients. In overall, we established a structure and the function relationship for ADAMTS13 and discovered the effects of cTTP causing mutations on ADAMTS13 structure. Additionally, we succeeded to generate novel ADAMTS13 spacer mutants which were able to resist against the autoantibodies while maintaining proteolytic activity. Next, we further observed the conformational changes of ADAMTS13 to better explain the interplay with its substrate VWF. Furthermore, we shared our strategic insights to modulate the protein-protein interactions and gave an example of how these strategies can be applied in the concept of TTP where the VWF and platelet interactions can be inhibited by structure-based design of a peptide inhibitor to prevent thrombocytopenia.  
In conclusion, our studies on the structure and function relationship of ADAMTS13 provided several insights to tackle the unmet needs of iTTP patients and they hold a significant potential to be included in the therapeutic arsenal of iTTP treatment. 

Chapters

Chapter 1
General introduction

Chapter 2
Insights into 3D-structure of ADAMTS13: a stepping stone towards novel therapeutic treatment of TTP Abstract

Chapter 3
Child‐onset thrombotic thrombocytopenic purpura caused by p. R498C and p. G259PfsX133 mutations in ADAMTS13 Abstract

Chapter 4
Modifying ADAMTS13 to modulate binding of pathogenic autoantibodies of patients with acquired thrombotic thrombocytopenic purpura Abstract

Chapter 5
N-glycan mediated shielding of ADAMTS13 prevents binding of pathogenic autoantibodies in immune-mediated TTP Abstract

Chapter 6
Modelling-assisted identification of CUB1/2 domain residues involved in maintaining ADAMTS13 in a closed conformation

Chapter 7
Conformational plasticity of ADAMTS13 in immune TTP;a blood-based remake of Dr. Jekyll and Mr. Hyde

Chapter 8
Rational modulator design by exploitation of protein-protein complex structures Abstract

Chapter 9
Structure-based design of cyclic glycoprotein Ibα-derived peptides affecting platelet interaction with von Willebrand factor under shear conditions

Chapter 10
General discussion

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Download PhD thesis (from university repository)