Gab2在SHP-2酪氨酸磷酸酶激活突变所致小鼠髓系异常增殖中的作用

AIM: To investigate whether Gab2, the key adapter protein in the SHP-2 signaling pathway, is involved in murine myeloid abnormal proliferation induced by SHP-2D61G/+ mutation. METHODS: Four kinds mouse model genotyped as WT, Gab2-/-, SHP-2D61G/+, SHP-2D61G/+/Gab2-/- was generated from crossbreeding of Gab2-/- and SHP-2D61G/+ mouse. The mouse spleen size was analyzed. The number of peripheral blood leukocytes was counted by cell counting and the percentage of myeloid cell (Mac-1 or Gr-1 positive) in bone marrow was detected by flow cytometry. The proliferation ability of bone marrow hematopoietic stem/ progenitor cell under cytokine was assay by colony formation. The expression of p-Erk and p-Akt and the binding capacity of SHP-2 with Gab2 in bone marrow derived mast cells stimulated with IL-3 was detected by Western blotting and IP. RESULTS: The phenotype of myeloid proliferation disorder, such as enlarged spleen size, increased leukocyte number and high percentage of myeloid cell in SHP-2D61G/+ mutant mice was found dramatically improved in SHP-2D61G/+,Gab2-/- double mutation mouse. Furthermore, compared with SHP-2D61G/ + mutation mouse, significantly decreased colony formation ability of bone marrow cell with IL-3 stimulation was found in SHP-2D61G/+/Gab2-/- double mutation mouse. A reduced phosphorylation level of Erk/Akt, and SHP-2 without binding with Gab2 was found in SHP-2D61G/+/Gab2-/- bone marrow-derived mast cells with IL-3 stimulation. CONCLUSIONS: Gab2 knockout can significantly reduce the murine myeloid abnormal proliferation induced by SHP-2D61G/+ mutation. The molecular mechanism may be associated with reduced binding with SHP-2D61G/+ under Gab2 knockout, and further weakened the activation of downstream signaling pathways Erk and Akt .