A transgenic zebrafish model expressing KIT‐D816V recapitulates features of aggressive systemic mastocytosis

Abstract

SummarySystemic mastocytosis (SM) is a rare myeloproliferative disease without curative therapy. Despite clinical variability, the majority of patients harbour a KIT-D816V mutation, but efforts to inhibit mutant KIT with tyrosine kinase inhibitors have been unsatisfactory, indicating a need for new preclinical approaches to identify alternative targets and novel therapies in this disease. Murine models to date have been limited and do not fully recapitulate the most aggressive forms of SM. We describe the generation of a transgenic zebrafish model expressing the human KIT-D816V mutation. Adult fish demonstrate a myeloproliferative disease phenotype, including features of aggressive SM in haematopoeitic tissues and high expression levels of endopeptidases, consistent with SM patients. Transgenic embryos demonstrate a cell-cycle phenotype with corresponding expression changes in genes associated with DNA maintenance and repair, such as reduced dnmt1. In addition, epcam was consistently downregulated in both transgenic adults and embryos. Decreased embryonic epcam expression was associated with reduced neuromast numbers, providing a robust in vivo phenotypic readout for chemical screening in KIT-D816V-induced disease. This study represents the first zebrafish model of a mast cell disease with an aggressive adult phenotype and embryonic markers that could be exploited to screen for novel agents in SM.

Branchial Pathomorphology of Southern Bluefin Tuna Thunnus maccoyii (Castelnau, 1872) Infected by Helminth and Copepodan Parasites

“…Sections were transferred after cooling to buffer (PBS + 1% BSA) then endogenous peroxidase activity was blocked (DAKO Envision System kit, K4006). Sections were rinsed in dH 2 O, immersed in buffer and incubated (30 min, room temp, 1:100) with mouse anti-human mast cell tryptase (DAKO M7052), which cross reacts with perciforme mast cells (Balla et al, 2010; Balci et al, 2014). Zebrafish gills served as a tissue control and a universal negative control (DAKO IR75066) was used for isotype control.…”

In vivo model for mastocytosis: A comparative review

“…More recently, Balci et al generated the first transgenic zebrafish model of a MC disease with an aggressive adult phenotype (expressing human KIT-D816V mutation and high levels of endopeptidases) and embryonic markers (expressing changes in genes associated with DNA repair and decreased epcam) [70]. Interestingly, this zebrafish model, representing fundamental features of aggressive SM, could be exploited to evaluate novel drugs in SM [70].…”

“…Interestingly, this zebrafish model, representing fundamental features of aggressive SM, could be exploited to evaluate novel drugs in SM [70].…”

Comparison of lesional skin c-KIT mutations with clinical phenotype in patients with mastocytosis

“…5 Many adults and some children with mastocytosis show expression of a somatic c-KIT mutation with a substitution of aspartic acid to valine at the 816 locus (D816V), 6,7 which has been shown to result in constitutively activated KIT and SCFindependent mast cell growth both in vitro and in experimental animals. 8,9 Other activating c-KIT mutations, including V560G and 502-503dupAY, have also been identified in a few patients with nodular mastocytosis and mast cell leukaemia, respectively. 10,11 However, the correlation of these c-KIT mutations with clinical phenotypes and disease persistence has been poorly characterized.…”