The Mechanism Of Activating Mutant Tyrosine Phosphatase SHP-2 Involved In Mouse Myeloproliferative Disorders

AIM: Study to demostrate whether activating mutant tyrosine phosphatase SHP-2 (PT- PN11) involved in mouse myeloproliferative disorders or not, a preliminary study of the possible molecular mechanism about SHP-2 participates in myeloproliferative disorders.METHODS: First comparised with the number of peripheral blood leukocytes in WT (wild-type) and SHP-2D61G / + mice, and with the change of week-old growth in relation- ships(That is to compare with the number of 8-week-old and 16-week-old mice peri- pheral blood leukocyte).Used the spleen of 16-week-old WT and SHP-2D61G / + mice to compare the spleen size,and calculated SI (spleen index= spleen weight (mg) / mouse weight) to determine the extent of relative increase in the spleen with the spleen of 8- week-old and16-week-old mice. FCM(Flow Cytometry)was applied to measure Mac- 1and Gr-1 on the peripheral blood leukocyte surface of WT and SHP-2 D61G / + mice,and counted the positive cell rate of Mac-1 and the positive cell rate of Ter119 (Erythroid), Mac-1and Gr-1 (Myeloid),CD3(T Lymphocytes) ,B220(B Lymphocytes) in the Bone marrow cells. We used BM CFU (Bone Marrow Colony forming Units) to analyse bone marrow proliferation of WT and SHP-2 D61G / + mice and observed the cell proliferation differences by counting . Gained mast cells by separating and culturing from Myeloid cells, MTS was used to observe cell proliferation of mast cells in IL3 (Interleukin -3 also known as multi-colony-stimulating factor, multi-F) stimulation. Detected the level of expression and phosphorylation of Erk and Art in the bone marrow-derived mast cells by SDS-PAGE and Western blot. Detected the binding capacity of SHP-2 with Gab-2 in IL-3 stimulation by Western blott and IP. The number of leukocytes in the peripheral blood was increaser(P<0.05), spleens were bigger in SHP-2 D61G / + than in WT. SI was heigher in 8-week-old and 16-week-old SHP-2 D61G / + than in WT. FCM showed that Mac-1and Gr-1 of the peripheral blood leukocytes were increased in 16-week-old SHP-2 D61G / +,Mac-1 positive cell rate was increased, Mac-1 and Gr-1 positive cell rate was also increased in the bone marrow cells of SHP-2D61G / + than WT,while surface marker positive cell rate of the erythroid and the lymphocyte did not change obviously. Two groups of mice with myeloid cells after induction with IL3, the colony-forming ability of bone marrow cells increased more obviously ,the phosphorylation level of Erk and Akt in the mast cells was higher in SHP-2 D61G / + than in WT . The binding capacity of SHP-2D61G/+ with Gab2 improved obviously.These point out that SHP-2 D61G / + leads to the proliferation of Myeloid cells,and gives rise to increase the phosphorylation level of Erk ,Art and the binding capacity of mutant SHP-2 with Gab2.CONCLUSIONS: The activating mutant SHP-2 D61G/+ involved in mouse myeloproli- ferative disorders, the molecular mechanism may be associated with SHP-2 D61G / + promotes the binding ability of Gab2,and further participates in theIL3-mediated Ras- Erk, PI3K-Akt signaling pathways .So SHP-2 could be the key element of the high value-added signal-regulated in myeloid cells and a important regulatory in the pathog- enesis of myeloproliferative disorders.