Publications by authors named "Allison C Ferguson"

3 Publications

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Acitretin mitigates uroporphyrin-induced bone defects in congenital erythropoietic porphyria models.

Sci Rep 2021 May 5;11(1):9601. Epub 2021 May 5.

Center for Advanced Biotechnology and Medicine, Rutgers University, Piscataway, 08854, USA.

Congenital erythropoietic porphyria (CEP) is a rare genetic disorder leading to accumulation of uro/coproporphyrin-I in tissues due to inhibition of uroporphyrinogen-III synthase. Clinical manifestations of CEP include bone fragility, severe photosensitivity and photomutilation. Currently there is no specific treatment for CEP, except bone marrow transplantation, and there is an unmet need for treating this orphan disease. Fluorescent porphyrins cause protein aggregation, which led us to hypothesize that uroporphyrin-I accumulation leads to protein aggregation and CEP-related bone phenotype. We developed a zebrafish model that phenocopies features of CEP. As in human patients, uroporphyrin-I accumulated in the bones of zebrafish, leading to impaired bone development. Furthermore, in an osteoblast-like cell line, uroporphyrin-I decreased mineralization, aggregated bone matrix proteins, activated endoplasmic reticulum stress and disrupted autophagy. Using high-throughput drug screening, we identified acitretin, a second-generation retinoid, and showed that it reduced uroporphyrin-I accumulation and its deleterious effects on bones. Our findings provide a new CEP experimental model and a potential repurposed therapeutic.
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http://dx.doi.org/10.1038/s41598-021-88668-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8100164PMC
May 2021

Disruption of the kringle 1 domain of prothrombin leads to late onset mortality in zebrafish.

Sci Rep 2020 03 4;10(1):4049. Epub 2020 Mar 4.

Department of Pediatrics, University of Michigan, Ann Arbor, MI, USA.

The ability to prevent blood loss in response to injury is a conserved function of all vertebrates. Complete deficiency of the central clotting enzyme prothrombin has never been observed in humans and is incompatible with postnatal life in mice, thus limiting the ability to study its role in vivo. Zebrafish are able to tolerate severe hemostatic deficiencies that are lethal in mammals. We have generated a targeted genetic deletion in the kringle 1 domain of zebrafish prothrombin. Homozygous mutant embryos develop normally into the mid-juvenile stage but demonstrate complete mortality by 2 months of age primarily due to internal hemorrhage. Mutants are unable to form occlusive venous and arterial thrombi in response to endothelial injury, a defect that was phenocopied using direct oral anticoagulants. Human prothrombin engineered with the equivalent mutation exhibits a severe reduction in secretion, thrombin generation, and fibrinogen cleavage. Together, these data demonstrate the conserved function of thrombin in zebrafish and provide insight into the role of kringle 1‚ÄČin prothrombin maturation and activity. Understanding how zebrafish are able to develop normally and survive into early adulthood without thrombin activity will provide important insight into its pleiotropic functions as well as the management of patients with bleeding disorders.
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http://dx.doi.org/10.1038/s41598-020-60840-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7055286PMC
March 2020

Analysis of factor V in zebrafish demonstrates minimal levels needed for early hemostasis.

Blood Adv 2019 06;3(11):1670-1680

Division of Pediatric Hematology/Oncology, Department of Pediatrics, University of Michigan School of Medicine, Ann Arbor, MI.

In humans, coagulation factor V (FV) deficiency is a rare, clinically heterogeneous bleeding disorder, suggesting that genetic modifiers may contribute to disease expressivity. Zebrafish possess many distinct advantages including high fecundity, optical clarity, external development, and homology with the mammalian hemostatic system, features that make it ideal for genetic studies. Our aim was to study the role of FV in zebrafish through targeted mutagenesis and apply the model to the study of human variants. CRISPR-mediated genome editing of the zebrafish locus was performed, generating mutants homozygous for a 49 base pair deletion in exon 4. Thrombus formation secondary to vascular endothelial injury was absent in mutant embryos and larvae. Despite this severe hemostatic defect, homozygous mutants survived before succumbing to severe hemorrhage in adulthood. Human variants of uncertain significance from patients with FV deficiency were evaluated, and the causative mutations identified and stratified by their ability to restore thrombus formation in larvae. Analysis of these novel mutations demonstrates variable residual FV function, with minimal activity being required to restore hemostasis in response to laser-induced endothelial injury. This in vivo evaluation may be beneficial for patients whose factor activity levels lack correlation with bleeding symptomatology, although limitations exist. Furthermore, homozygous mutant embryos tolerate what is a severe and lethal defect in mammals, suggesting the possibility of species-specific factors enabling survival, and allowing further study not possible in the mouse. Identification of these factors or other genetic modifiers could lead to novel therapeutic modalities.
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http://dx.doi.org/10.1182/bloodadvances.2018029066DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6560344PMC
June 2019