LSBR Anniversary Grant

LSBR ANNIVERSARY GRANT

HEMOTWIN-BD: Dissecting Proteoforms in Bleeding Disorders

The HemoTwin-BD project will investigate how qualitative and quantitative variants of hemostatic proteins (proteoforms) present in plasma, platelets and endothelial cells contribute to the variability of bleeding phenotypes in patients with congenital bleeding disorders (CBDs) or bleeding disorders of unknown cause (BDUC). A key unresolved challenge in the management of these disorders is why some individuals experience severe bleeding while others with the same diagnosis or similar laboratory results do not. This variability within disorders remains largely unexplained because the underlying molecular mechanisms—at the protein level—are not captured by current genetic and functional diagnostics.

Bleeding disorders are traditionally studied within isolated diagnostic categories, limiting the ability to uncover shared disease mechanisms. Particularly, heavy menstrual bleeding (HMB) is considered a major clinical challenge in the field. Although evidence suggests that HMB may be linked to bleeding severity, there is a lack of evidence for congenital deficiencies in this group. Current diagnostic laboratory testing fails to define any abnormalities responsible for the bleeding phenotype seen in these women, and they are often classified as a BDUC. However, it is likely that different levels and/or proteoforms of critical hemostatic proteins underly HMB. In addition, other clinical features, including postpartum hemorrhage, peri-operative bleeding and joint damage, are observed across different bleeding disorders and may occur independent of traditional diagnostic classifications. This suggests the existence of common proteoform variants or shared biological modifiers that influence bleeding risk across different diagnoses. HemoTwin-BD aims to address these knowledge gaps by applying a systems-level approach that combines deep proteomic phenotyping with the integration of nationwide, well-characterized clinical cohorts. By analyzing these cohorts both individually and in combination, the project seeks to resolve outstanding questions within specific bleeding disorders and to enable the discovery of shared mechanisms underlying bleeding variability.

The work plan is structured around four work packages (WPs). WP1 maps Willebrand factor (VWF) proteoforms and their impact on trafficking and function in von Willebrand Disease (VWD). WP2 quantifies variant coagulation factor proteoforms and assesses their contribution to stage-specific defects in secondary hemostasis and fibrinolysis. WP3 defines proteomic signatures in BDUC using multi-omic profiling of plasma, platelet, and endothelial proteins. WP4 integrates clinical, diagnostic, and molecular data into an AI-driven platform - HemoTwin-BD - to improve bleeding severity stratification and predict treatment response.

Together, these WPs will create an in-depth, individualized map of bleeding risk and treatment response, moving diagnostics beyond “one-size-fits-all” to a tailored, proteoform-level understanding for patient stratification, and individualized treatment planning. Leveraging advanced mass spectrometry-based multi-proteomics for in-depth molecular profiling with Artificial Intelligence (AI)-guided machine learning, the project will identify key molecular determinants of bleeding variability and support improved risk assessment and therapeutic decision-making. Building on nationwide collaboration among Dutch hematologists as well as the continuous advancement of technological innovation at Sanquin, this consortium is uniquely positioned to deliver translational impact on care for individuals with a bleeding disorder.

This project builds on an established research line at Sanquin Research within the Medical Priority Bleeding & Hemostasis, specifically the group led by Dr. Maartje van den Biggelaar, which focuses on Proteomics and Biomolecular Mass Spectrometry of Hemostatic Processes. The group investigates how molecular diversity in hemostatic proteins—including post-translational modifications, receptor interactions, and structural variants—affects protein function, trafficking, and ultimately bleeding risk in patients with hemostatic disorders. Over recent years, this line of investigation has evolved to apply mass spectrometry-based approaches to study VWF, Factor VIII, and other hemostatic proteins in clinical and experimental contexts. Equally critical to the foundation of this project are the longstanding research lines of the Dutch HTCs, which serve as national expertise centers and play a pivotal role in the clinical and translational research agenda for all inherited bleeding disorders in the Netherlands.

Erasmus UMC: Dr. Ferdows Atiq and Dr. Ruben Bierings (Hematology) focus on the pathophysiology and clinical variability of VWD.

Hemophilia Treatment Center Nijmegen-Eindhoven-Maastricht (HBC-NEM), location Radboudumc: Dr. Saskia Schols leads the national RBiN study.

Treatment Center Nijmegen-Eindhoven-Maastricht (HBC-NEM), location MUMC+: Dr. Floor Heubel-Moenen leads national research efforts in BDUC through the retro-BDUC-iN and prospective BDUC-iN cohort studies.

Amsterdam UMC: Dr. Samantha Gouw leads research in HA and HB, with a focus on treatment optimization, phenotypic heterogeneity, and personalized therapeutic strategies in children.

UMC Utrecht: Dr. Rolf Urbanus leads mechanistic research in PFDs, including the TiN study.

This program will offer the unique opportunity to take the next step and integrate AI in the research lines. We will collaborate with the Informatics Institute at the University of Amsterdam (Prof. Dr. Alfons Hoekstra). The institute is on the forefront of fundamental scientific research and innovation in Information Sciences, with a focus on Artificial Intelligence, Data Science, Systems and Security, and Computational and Complexity Sciences.