Human iPSC-MSC-Derived Xenografts Modulate Immune Responses by Inhibiting the Cleavage of Caspases.

Mesenchymal stem cells (MSCs) negatively modulate immune properties. Induced pluripotent stem cells (iPSCs)-derived MSCs are alternative source of MSCs. However, the effects of iPSC-MSCs on T cells phenotypes in vivo remain unclear. We established an iPSC-MSC-transplanted host versus graft reaction mouse model using subcapsular kidney injection. Th1, Th2, regulatory T cells (Treg), and Th17 phenotypes and their cytokines were investigated in vivo and in vitro. The role of caspases and the soluble factors involved in the effects of MSCs were examined. We found that iPSC-MSC grafts led to more cell survival and less infiltration of inflammatory cells in mice. iPSC-MSC transplantation inhibited T cell proliferation, decreased Th1 and Th2 phenotypes and cytokines, upregulated Th17 and Treg subsets. Moreover, iPSC-MSCs inhibited the cleavage of caspases 3 and 8 and inhibition of caspases downregulated Th1, Th2 responses and upregulated Th17, Treg responses. Soluble factors were determined using protein array and TGF-ß1/2/3, IL-10, and MCP-1 were found to be highly expressed in iPSC-MSCs. The administration of the soluble factors decreased Th1/2 response, upregulated Treg response and inhibited the cleavage of caspases. Our results demonstrate that iPSC-MSCs regulate T cell responses as a result of a combined action of the above soluble factors secreted by iPSC-MSCs. These factors suppress T cell responses by inhibiting the cleavage of caspases. These data provide a novel immunomodulatory mechanism for the underlying iPSC-MSC-based immunomodulatory effects on T cell responses. Stem Cells 2017;35:1719-1732.

[Gene expression and activities analysis of a new fusion protein (RGD) 3/tTF].

To develop a new fusion protein (RGD)3/tTF for the therapy of the selective thrombosis of tumor blood vessels. The fused gene (RGD) 3/tTF was reconstructed by PCR, was cloned into vector pET22 b(+), and expressed in E. coli BL21 (DE3). The fusion protein was purified through Nickel-affinity chromatography column. The tTF activity of the fusion protein was detected by clotting assay and F X activation assay. The specific binding of (RGD) 3/tTF to alphavbeta3 was analyzed by indirect ELISA. The recombinant plasmid pET22 b(+)/(RGD)3/tTF was obtained and expressed in E. coli BL21 (DE3). The purified fusion protein could induce blood coagulation, activiate F X. The ability of (RGD) 3/tTF binding specifically to alphavbeta3 was increased by 32%, compared with RGD/tTF. A new fusion protein (RGD) 3/tTF was successfully expressed in E. coli BL21 (DE3). The expressed proteins retained tTF activity and showed a higher binding to alphavbeta3 than that of RGD/tTF.

[Enhancement of glioma cell apoptosis induced by anti-human DR5/DR4 monoclonal antibodies by sub-toxic dose of doxorubicin in human].

AIM: To study the cytotoxic effects of doxorubicin on apoptosis in glioma cell lines U343, U138, U373 induced by anti-human DR4/DR5 monoclonal antibodies (FMU1.4/FMU1.5) and the underlying mechanism. METHODS: Expression of DR4/DR5 was quantitated by flow cytometry. Cytotoxicity exerted by FMU1.4/FMU1.5 on three cell lines was measured by MTT colorimetry and the induced apoptosis was determined by agarose gel electrophoresis. The expression of cytochrome C, FLIP and Ca2+ concentration were also measured. RESULTS: Following the treatment of doxorubicin DR4 and DR5 were highly expressed on the cell surface; The apoptosis of U138 and U373 induced by FMU1.4 and FMU1.5 was stronger. expression of cytochrome C and Ca2+ concentration were enhanced, whereas the expression of FLIP was downregulated. CONCLUSION: Subtoxic doxorubicin applied with antibodies caused higher cell death rate of glioma cells, which may be relevant to DR4/DR5, the release of cytochrome C and FLIP and Ca2+ concentration.

[Gene's construction, expression and activity analysis of humanized single-domain antibody against human lung cancer].

AIM: To construct the gene of humanized single-domain antibody hu3D3V(H) against human lung cancer, to express it in E.coli and analyze its activity. METHODS: The mAb3D3V(H) was humanized by using CDRs grafting technique. The hu3D3V(H) gene was assembled by overlapping PCR. The expression vector pET22(b+)/hu3D3V(H) was constructed and transformed into E.coli BL21(DE3) and the hu3D3V(H) protein was expressed under IPTG induction. After purification by Ni(2+)-affinity chromatographic column, the activity of hu3D3V(H) protein was analyzed by indirect ELISA and competitive inhibition ELISA. RESULTS: The target gene with correct sequence was obtained by overlapping PCR. The hu3D3V(H) protein was expressed as inclusion bodies with the yield of more than 30% of total bacterial proteins. After purification, the purity of hu3D3V(H) was more than 95%. The reactivity of purified protein was the same as parent antibody, and could inhibit the binding of mAb3D3 to L342 cells. CONCLUSION: The hu3D3V(H) still retains the reactivity and specificity of mAb3D3, which lays the foundation for its further clinical application.