Effect of transgenic Leishmania major expressing mLLO-Bax-Smac fusion gene in the apoptosis of the infected macrophages

Objective(s): Leishmaniasis is a complex infection against which no confirmed vaccine has been reported so far. Transgenic expression of proteins involved in macrophage apoptosis-like BAX through the parasite itself accelerates infected macrophage apoptosis and prevents Leishmania differentiation. So, in the present research, the impact of the transgenic Leishmania major including mLLO-BAX-SMAC proapoptotic proteins was assayed in macrophage apoptosis acceleration. Materials and Methods: The coding sequence mLLO-Bax-Smac was designed and integrated into the pLexyNeo2 plasmid. The designed sequence was inserted under the 18srRNA locus into the L. major genome using homologous recombination. Then, mLLO-BAX-SMAC expression was studied using the Western blot, and the transgenic parasite pathogenesis was investigated compared with wild-type L. major in vitro and also in vivo. Results: Western blot and PCR results approved mLLO-BAX-SMAC expression and proper integration of the mLLO-Bax-Smac fragment under the 18srRNA locus of L. major, respectively. The flow cytometry results revealed faster apoptosis of transgenic Leishmania-infected macrophages compared with wildtype parasite-infected macrophages. Also, the mild lesion with the less parasitic burden of the spleen was observed only in transgenic Leishmania-infected mice. The delayed progression of leishmaniasis was obtained in transgenic strain-injected mice after challenging with wild-type Leishmania. Conclusion: This study recommended transgenic L. major including mLLO-BAX-SMAC construct as a pilot model for providing a protective vaccine against leishmaniasis

Phenotypic Characterizations and Comparison of Adult Dental Stem Cells with Adipose-Derived Stem Cells

Objectives: Mesenchymal stem cells or ′′multipotent stromal cells′′ are heterogeneous cell population with self-renewal and multi-linage differentiation. The aim of this study was to examine and compare the expression of important stem cell surface mark-ers on two populations of mesenchymal stem cells, one derived from human exfoliated deciduous teeth and the other derived from human adipose tissue. These new stem cells will offer a promising avenue for prevention and reversal of many human diseases such as type 1 diabetes and prevention of liver fibrotic process. Methods: Mesenchymal stem cells were isolated and cultured from human adipose tissue and dental pulp of human exfoliated deciduous teeth. The cultured cells then were harvested and stained by different fluorescent labeled monoclonal antibodies against surface markers and were analyzed using flow cytometry. Results: Both different cell populations expressed CD44, CD90 and CD13 (stem cell markers) with similar intensity. They did not express hematopoietic markers (CD11b, CD19 and CD34), and lymphocyte or leukocyte antigens CD3, CD7, CD20, CD14, CD45, CCR5 (CD195), CD11b and CD10 on their surfaces. Two different cell types demonstrated different levels of expression in CD56 and CD146. Mesenchymal stem cells from human exfoli-ated deciduous teeth were positive for CD105 and were negative for CCR3 and CCR4 expression. Conclusions: Both cell populations derived from adipose tissue and dental pulp showed common phenotypic markers of mesenchymal stem cells. In conclusion, mesenchymal stem cells could be isolated and cultured successfully from dental pulp of human exfo-liated deciduous teeth, they are very good candidates for treatment and prevention of human diseases