A novel zebrafish jak2a^V581F model shared features of human JAK2^V617F polycythemia vera

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• 作者：Alvin C.H. Ma ; August Fan ; Alister C. Ward ; Clifford Liongue ; Rowena S. Lewis ; Suk H. Cheng ; P.K. Chan ; Sze-Fai Yip ; Raymond Liang ; Anskar Y.H. Leung
• 刊名：Experimental Hematology
• 出版年：2009
• 出版时间：December 2009
• 年：2009
• 卷：37
• 期：12
• 页码：1379-1386.e4
• 全文大小：3624 K

文摘

Objective

The Janus kinase 2 (JAK2) is important for embryonic primitive hematopoiesis. A gain-of-function JAK2 (JAK2^V617F) mutation in human is pathogenetically linked to polycythemia vera (PV). In this study, we generated a zebrafish ortholog of human JAK2^V617F (referred herewith jak2a^V581F) by site-directed mutagenesis and examined its relevance as a model of human PV.

Materials and Methods

Zebrafish embryos at one-cell stage were injected with jak2a^V581F mRNA (200pg/embryo). In some experiments, the embryos were treated with a specific JAK2 inhibitor, TG101209. The effects of jak2a stimulation on hematopoiesis, jak/stat signaling, and erythropoietin signaling were evaluated at 18-somites.

Results

Injection with jak2a^V581F mRNA significantly increased erythropoiesis, as enumerated by flow cytometry based on gfp⁺ population in dissociated Tg(gata1:gfp) embryos. The response was reduced by stat5.1 morpholino coinjection (control: 4.37 % ± 0.08 % ; jak2a^V581F injected: 5.71 % ± 0.07 % , coinjecting jak2a^V581F mRNA and stat5.1 morpholino: 4.66 % ± 0.13 % ; p < 0.01). jak2a^V581F mRNA also upregulated gata1 (1.83 ± 0.08 fold; p = 0.005), embryonic α-hemoglobin (1.61 ± 0.12 fold; p = 0.049), and β-hemoglobin gene expression (1.65 ± 0.13–fold; p = 0.026) and increased stat5 phosphorylation. These responses were also ameliorated by stat5.1 morpholino coinjection or treatment with a specific JAK2 inhibitor, TG101209. jak2a^V581F mRNA significantly reduced erythropoietin gene (0.24 ± 0.03 fold; p = 0.006) and protein expression (control: 0.633 ± 0.11; jak2a^V581F mRNA: 0.222 ± 0.07 mIU/mL; p = 0.019).

Conclusion

The zebrafish jak2a^V581F model shared many features with human PV and might provide us with mechanistic insights of this disease.