The Pathologic And Physiologic Role Of Zfyve16 In Hematopoietic System

Background: Acute myeloid leukemia(AML)is a type of hematopoietic malignancy caused by myeloid cells with abnormal differentiation and proliferation.More than 30% of AML patients harbor various FLT3 mutations.,FLT3 is a tyrosine kinase receptor specifically expressed on the surface of hematopoietic stem and progenitor cells and plays an important role in cell proliferation,growth and differentiation.Due to the poor prognosis of AML patients with FLT3 mutations,the pathogenesis of FLT3 mutations and their targeted therapy have been enthusiastically investigated in the field of AML treatment.To indentify potential novel therapeutic targets in regulating the leukemogenesis of FLT3 mutations,we analyze the mRNA sequencing data of some AML patients from the TCGA database(The Cancer Genome Atlas,USA).We found that,in a group of the patients with FLT3 mutations that had better prognosis,ZFYVE16 gene expression was significantly increased.It is reported that ZFYVE16 is involved in many signaling pathways such as TGF-β,EGFR,BMP,etc.TGF-β signaling pathway plays a negative regulatory role in hematopoietic cell proliferation and differentiation.When ZFYVE16 overexpressed,the negative effect of TGF-β signaling this effect might inhibit FLT3.Therefore,we hypothesize that the elevation of ZFYVE16 might suppress the relapse of AML caused by FLT3 mutations to a certain extent.Methods: To investigate the biological interaction between ZFYVE16 and FLT3-ITD at the cellular level,we established the co-expressed cell lines infected by retrovirus.Meantime,we also generated a Zfyve16 gene knockout mouse line to analyze the physiological and pathological role of Zfyve16 in hematopoietic system.Results:(1)In the cellular level,we found the overexpression of ZFYVE16 gene may affect aggressive cell proliferation of FLT3-ITD to some extent,which was confirmed by Western blotting results;(2)In mouse,we found Zfyve16 is widely expressed in the bone marrow,spleen,liver,and other hematopoietic organs.(3)By using the cell proliferation assay and colony formation assay,we discovered that self-renewal capability of pre-B cell is weakened and TGF-β signaling in pre-B cell is also diminished in Zfyve16 deficient mice.(4)However,during an 8-month consecutive followup study,we found Zfyve16 knockout mice appear normal in a homeostatic hematopoietic system.There are no major differences in the quantity and quality of hematopoietic stem cells between wildtype and knockout mice.