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| Author(s): |
Taccyanna Mikulski Ali
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Faculdade de Medicina (FM/SBD) |
| Defense date: | 2015-08-27 |
| Examining board members: |
Edecio Cunha Neto;
Flávia Afonso Lima
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| Advisor: | Edecio Cunha Neto |
| Abstract | |
INTRODUCTION: HIG2 molecule can act as an agonist of Wnt/?-catenin pathway, because it able to bind to Frizzled 10 receptor and induce the expression of the genes related to this pathway. Recent data from our group have shown differential expression of the HIG2 gene in peripheral blood mononuclear cells, and particularly in naive CD4 + T cells, but not in memory T cells in healthy individuals. We have also observed that inducing the CD4 + T lymphocytes from healthy individuals with HIG2 synthetic peptide in vitro, led to the activation of Wnt/beta-catenin pathway, HIG2 production and expression of other target genes of this pathway and the proliferation of naïve CD4 + T cells, suggesting that HIG2 may play a role in homeostatic proliferation of CD4+ T cells. HYPOTHESIS: As naïve CD4 + T cells are directly exported from the thymus, we have hypothesized that increased levels of HIG2 in this cell type is due to the activation of Wnt/beta-catenin pathway in the later stages of thymocyte differentiation. Therefore, naïve CD4 + T cells and CD4 single-positive thymocytes (CD4 SP) may share a similar pattern of gene expression of HIG2 and Wnt/beta-catenin genes (genes that encodes receptors and co-receptors, transcription factors, structural and target genes) when compared to other cell populations. AIM: our major aim is to evaluate the expression of HIG2 and other genes of the Wnt/beta-catenin in thymocytes, naïve CD4 + T lymphocytes and memory CD4+ T cells from mice. METHODS: We have isolated thymocytes double negative (DN) T cells, positive double positive (DP) T cells, CD4 and CD8 single-positive thymocytes (CD4 SP and CD8 SP) of thymus from BALB/c mice and we have also isolated naïve CD4 + T cells and memory CD4+ T cells of the spleen from the same mice we have used the thymus. We have analysed the expression of several genes of Wnt/beta-catenin by real time PCR RESULTS: In DN cells there was expression of the Frizzled 6, LRP5, TCF-1 and TCF-4 genes compared to other cell populations. In DP thymocytes it could be observed a greater expression of LRP5, LRP6, beta-catenin, GSK-3beta, TCF-1 and Bcl-XL genes compared to other populations. In CD4 SP thymocytes, it was detected differential expression of the Frizzled 10, LRP6, beta-catenin, LEF-1 HIG2 genes and in CD8 SP cells we could not observe significant expression of any gene of Wnt/?-catenin pathway. In naïve CD4 + T cells there was a significant expression of Frizzled5 and Frizzled 10 genes when compared to all the samples. In memory CD4 + T cells, we have detected higher expression of Frizzled 6, TCF-4, Bcl-XL and cyclin D1 genes than in any other populations. CONCLUSION: Each population has a distinct gene expression pattern. The biggest similarities occur between DN and DP thymocytes where the main differences are the expression of Frizzled 6 and cyclin D1.However, the pattern of gene expression in SP thymocytes is not similar to those presented by naïve CD4+ T cells. Moreover, we have not observed increased expression of HIG2 in naïve CD4 + lymphocytes compared to memory CD4+ T cells, which contrasts the results obtained previously by our group with human samples suggesting that mice might not regulate the HIG2 expression in CD4 + T lymphocytes as human beings do (AU) | |
| FAPESP's process: | 12/13584-8 - Gene expression profiles of Wnt/²-catenin pathway elements in thymocytes and CD4 + T lymphocytes of BALB/c mice |
| Grantee: | Taccyanna Mikulski Ali |
| Support Opportunities: | Scholarships in Brazil - Master |