Abstract Number: PB0130
Meeting: ISTH 2020 Congress
Background: The anatomical and temporal bioavailability of hemostatic components may control distinct (cellular) processes. However, tools to non-invasively visualize the expression dynamics and spatiotemporal distribution of such proteins at a systems level are scarce.
Aims: Here we set out (1) to generate a reporter-mouse model to interrogate the spatiotemporal dynamics of prothrombin (F2) expression, and (2) to explore the suitability of this model to identify cellular programs executed by extrahepatic expression of this central hemostatic component.
Methods: Utilizing a multimodal tagging strategy, a novel constitutive knock-in reporter-mouse model was created. This model is based on fluorescence and luminescence reporters separated by P2A peptides for tailored multicistronic expression. It enables simultaneous monitoring of the expression and secretion dynamics of prothrombin in its physiological context in a living animal with non-invasive optical imaging. Septicemia and tumor induction were used to validate the model. Complementary syngenic (primary) cell lines derived from this mouse model were used to deconvolute regulatory mechanisms in high resolution. The functional dimension of extrahepatic prothrombin was probed by targeted depletion in vivo and in vitro, coagulation assays and RNAseq.
Results: In a proof-of-concept, we confirm that this newly generated reporter-mouse model faithfully recapitulates established modifiers of F2 expression. We further discover extrahepatic F2 expression in emerging fibrosarcomas, resulting in significant amounts of functional tumor-derived prothrombin in the bloodstream. By selective ablation, we identify that tumor-derived prothrombin functionally contributes to a procoagulant and protumorigenic state. RNA expression analysis identifies central cellular programs perturbed by tumor-intrinsic prothrombin.
Conclusions: Using a newly generated reporter system, we uncover previously unknown sources of harmful F2 expression. Beyond discovering new functions of the hemostatic system, this model is widely applicable to identify rheostats involved in the cross-talk between gene expression and bioavailability of a secretory protein. It may also represent a resource to uncover novel (tissue-specific) therapeutic vulnerabilities.
To cite this abstract in AMA style:Schott LK, Pruschinski L, Khokar S, Eder L, Muhammad K, Tokalov S, Satrapa J, Klein M, Lackner K, Danckwardt S. Non-Invasive Optical in vivo Imaging Reveals Tumor-Derived Prothrombin with a Functional Role in Hemostasis and Tumor Progression [abstract]. Res Pract Thromb Haemost. 2020; 4 (Suppl 1). https://abstracts.isth.org/abstract/non-invasive-optical-in-vivo-imaging-reveals-tumor-derived-prothrombin-with-a-functional-role-in-hemostasis-and-tumor-progression/. Accessed May 6, 2021.
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