Fishing for answers to hemostatic and thrombotic disease: Genome editing in zebrafish.

Over the past two decades, the teleost vertebrate Danio rerio (zebrafish) has emerged as a model for hemostasis and thrombosis. At genomic and functional levels, there is a high degree of conservation of the hemostatic system with that of mammals. Numerous features of the fish model offer unique advantages for investigating hemostasis and thrombosis. These include high fecundity, rapid and external development, optical transparency, and extensive functional homology with mammalian hemostasis and thrombosis. Zebrafish are particularly suited to genome-wide mutagenesis experiments for the study of modifier genes. They are also amenable to whole-organism small-molecule screens, a feature that is exceptionally relevant to hemostasis and thrombosis. Zebrafish coagulation factor knockouts that are in utero or neonatal lethal in mammals survive into adulthood before succumbing to hemorrhage or thrombosis, enabling studies not possible in mammals. In this illustrated review, we outline how zebrafish have been employed for the study of hemostasis and thrombosis using modern genome editing techniques, coagulation assays in larvae, and in vivo evaluation of patient-specific variants to infer causality and demonstrate pathogenicity. Zebrafish hemostasis and thrombosis models will continue to serve as a clinically directed basic research tool and powerful alternative to mammals for the development of new diagnostic markers and novel therapeutics for coagulation disorders through high-throughput genetic and small-molecule studies.

The zebrafish hemostatic system is highly conserved with mammals genomically and functionally.

Hemostatic disease models produced using genome editing show conservation with human disorders.

Zebrafish coagulation factor mutants that are early lethal in mammals survive into adulthood.

Potential disease‐causing variants can be rapidly assessed in vivo using zebrafish knockouts.

AUTHOR CONTRIBUTIONS

AR and JS developed the concepts and wrote the manuscript. AR and AF produced the illustrations. AR, AF, and JS approved the final content.

FUNDING INFORMATION

This work was supported by the National Hemophilia Foundation Judith Graham Pool Postdoctoral Fellowship Award (AR), and National Institutes of Health grants R35HL150784 and R01ES032255 (JAS). JAS is the Henry and Mala Dorfman Family Professor of Pediatric Hematology/Oncology.

RELATIONSHIP DISCLOSURE

JAS has been a consultant for Sanofi, Takeda, CSL Behring, HEMA Biologics, and Bayer. AR and ACF report no conflicts of interest.