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| Author(s): |
Bruno Rafael Barboza
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Ribeirão Preto. |
| Institution: | Universidade de São Paulo (USP). Faculdade de Medicina de Ribeirão Preto (PCARP/BC) |
| Defense date: | 2020-12-16 |
| Examining board members: |
Thiago Aparecido da Silva;
Eduardo Isidoro Carneiro Beltrão;
Fabíola Traina
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| Advisor: | Thiago Aparecido da Silva |
| Abstract | |
The ArtinM lectin, obtained from the saline extract of seeds of Artocarpus heterophyllus (jackfruit), is structurally characterized as a homotetramer of 16 kDa subunits, each each consisting of a CRD with primary binding site for Manα1-3[Manα1-6]Manβ1-4, structure present in the N-glycans core. ArtinM induces mast cell activation (via interaction with FcεRI), neutrophils (via interaction with CXCR2/TLR2), macrophages (via interaction with TLR2/CD14), and activation of CD4+ T and CD8+ T cells (via interaction with the gamma chain of CD3). The immunomodulatory activity of ArtinM on these cells results in a proinflammatory profile with the ability to combat infections by intracellular pathogens. Recently, murine B cells were included as targets of ArtinM that induced the production of IL-17 and IL- 12p40 in that cell type, independently manner of TLR2/CD14 recognition. Thus, the present study sought to characterize the effects of ArtinM in murine B cells and human non-Hodgkin lymphoma cell lines, highlighting the molecular mechanisms induced after carbohydrate recognition. Initially, murine B cells purified from C57BL/6 mice were incubated with different concentrations of ArtinM (0.312 - 5.0 μg/mL), and lectin did not induce cell proliferation and low levels of IL-2, IFN-ϒ and IL-12 were produced by B cells. However, the lectin concentrations tested, with emphasis on high concentrations, induced apoptosis of murine B cells. Therefore, ArtinM does not have an immunomodulatory effect on B cells that directs an immune response associated with the Th1 profile. Therefore, the cytotoxic effect of lectin on B cells originating from non-Hodgkin\'s lymphoma was evaluated, from the cell lines Raji and Daudi. When exploring the effect of ArtinM on these cell lines, we observed the ability of ArtinM to reduce cell growth and viability with different intensity for each cell type, with a more pronounced cytotoxic effect on Raji cells. Thus, when deepening the evaluation of the cytotoxic effect of ArtinM in Raji cells, we verified the absence of DNA fragmentation and a strong indication of the exclusion of the apoptosis cascade via mitochondrial and signaling molecules of the autophagy pathway. Thus, possible signaling molecules involved in the cytotoxic effect of ArtinM in non-Hodgkin\'s lymphoma cells were investigated with the use of specific pharmacological inhibitors for PKC, PTK, CD45 phosphatase activity in Lck, and kinases of Src family. This approach implied that the induction of apoptosis by ArtinM in Raji cells is related to the following molecular mechanisms, such as: (i) PTK and PKC downregulate the induction of apoptosis in Raji cells by ArtinM; (ii) the phosphatase activity of CD45 in Lck down-regulate the cytotoxic effect of ArtinM in Raji cells; (iii) Src kinases regulate positively the induction of Raji cell apoptosis by ArtinM. Therefore, ArtinM has a cytotoxic effect in non-Hodgkin\'s lymphoma B cell lines. The present work demonstrates the limitations of the immunomodulatory effect of ArtinM in murine B cells, and creates an important investigative area in the therapeutic field against non-Hodgkin\'s lymphoma cells through the recognition of carbohydrates. (AU) | |
| FAPESP's process: | 19/05867-9 - Effect of ArtinM on B and NK cells |
| Grantee: | Bruno Rafael Barboza |
| Support Opportunities: | Scholarships in Brazil - Master |