ABSTRACT
【Objective】 To observe the penetration and biological activity of PTD4-Cu, Zn-SOD into human astrocytes and whether it can mitigate hypoxia damages. 【Methods】 ①Immunohistochemistry and fluorescence test: We labeled the Cu, Zn-SOD by a monoclonal antibody, combined it with the fluorescent secondary antibody labeled with fluorescein isothiocyanate (FITC) to observe the effect of transduced PTD4-Cu, Zn-SOD on the viability of human astrocytes. ② The experimental group: After hypoxic damage model, the cells were divided into three groups: blank control, group Cu, Zn-SOD, and group PTD4-Cu, Zn-SOD. Group blank was added with DMEM medium (excluding serum) as control; DMEM medium was added to the other two for one hour (excluding serum) with its fusion proteins (Cu, Zn-SOD and PTD4 -Cu, Zn-SOD) with the final concentration of 2 μmoL/L. After the intervention, we used SOD and MDA test kits to observe PTD4-Cu, Zn-SOD and Cu, Zn-SOD in astrocytes after fusion protein intervention. 【Results】 The PTD4-Cu, Zn-SOD fusion protein could have aggregation distribution in the nucleus by FITC fluorescently labeled. After the intervention, it could increase the SOD activity in astrocytes in group PTD4-Cu, Zn-SOD and group Cu, Zn-SOD compared with control group, but the SOD activity was more obvious in the fusion proteins PTD4-Cu, Zn-SOD group. And the dose of MDA was reduced in group PTD4-Cu, Zn-SOD compared with group Cu, Zn-SOD and control group. 【Conclusion】 PTD4-Cu, Zn-SOD fusion protein can transcellular membrane of human astrocytes. The fusion protein PTD4-Cu, Zn-SOD can increase the SOD activity and reduce the content of MDA by human astrocytes from hypoxia injury.
ABSTRACT
Acute myeloid leukaemia (AML) is a haematological malignancy characterized by a poor prognosis. Bone marrow mesenchymal stromal cells (BM MSCs) support leukaemic cells in preventing chemotherapy-induced apoptosis. This encouraged us to investigate leukaemia-BM niche-associated signalling and to identify signalling cascades supporting the interaction of leukaemic cells and BM MSC. Our study demonstrated functional differences between MSCs originating from leukaemic (AML MSCs) and healthy donors (HD MSCs). The direct interaction of leukaemic and AML MSCs was indispensable in influencing AML cell proliferation. We further identified an important role for Notch expression and its activation in AML MSCs contributing to the enhanced proliferation of AML cells. Supporting this observation, overexpression of the intracellular Notch domain (Notch ICN) in AML MSCs enhanced AML cells' proliferation. From a therapeutic point of view, dexamethasone treatment impeded Notch signalling in AML MSCs resulting in reduced AML cell proliferation. Concurrent with our data, Notch inhibitors had only a marginal effect on leukaemic cells alone but strongly influenced Notch signalling in AML MSCs and abrogated their cytoprotective function on AML cells. In vivo, dexamethasone treatment impeded Notch signalling in AML MSCs leading to a reduced number of AML MSCs and improved survival of leukaemic mice. In summary, targeting the interaction of leukaemic cells and AML MSCs using dexamethasone or Notch inhibitors might further improve treatment outcomes in AML patients.
