EDUARDO MILTON RAMOS SANCHEZ
Projetos de Pesquisa
Unidades Organizacionais
LIM/38 - Laboratório de Epidemiologia e Imunobiologia, Hospital das Clínicas, Faculdade de Medicina
4 resultados
Resultados de Busca
Agora exibindo 1 - 4 de 4
conferenceObject Analysis of global gene expression of Leishmania infantum under Insulin-like growth factor I stimulus(2015) RAMOS-SANCHEZ, E. M.; NERLAND, A. H.; GOTO, H.- Insulin-Like Growth Factor-I as an Effector Element of the Cytokine IL-4 in the Development of a Leishmania major Infection(2018) REIS, Luiza C.; RAMOS-SANCHEZ, Eduardo Milton; PETITTO-ASSIS, Fabricio; NERLAND, Audun H.; HERNANDEZ-VALLADARES, Maria; SELHEIM, Frode; FLOETER-WINTER, Lucile Maria; GOTO, HiroCertain cytokines modulate the expression of insulin-like growth factor-(IGF-) I. Since IL-4 and IGF-I promote growth of the protozoan Leishmania major, we here addressed their interaction in downregulating the expression of Igf-I mRNA using small interfering RNA (siRNA) in Leishmania major-infected macrophages. Parasitism was decreased in the siRNA-treated cells compared with the nontreated cells, reversed by the addition of recombinant IGF-I (rIGF-I). In IL-4-stimulated macrophages, parasitism and the Igf-I mRNA amount were increased, and the effects were nullified upon siRNA transfection. IGF-I downregulation inhibited both parasite and macrophage arginase activation even in IL-4-stimulated cells. Searching for intracellular signaling components shared by IL-4 and IGF-I, upon siRNA transfection, phosphorylated p44, p38, and Akt proteins were decreased, affecting the phosphatidylinositol-3-kinase (PI3K)/Akt pathway. In L. major-infected C57BL6-resistant mice, the preincubation of the parasite with rIGF-I changed the infection profile to be similar to that of susceptible mice. We conclude that IGF-I constitutes an effector element of IL-4 involving the PI3K/Akt pathway during L. major infection.
conferenceObject INSULIN-LIKE GROWTH FACTOR-I AS EFFECTOR ELEMENT OF IL-4 EFFECT LEADING TO SUSCEPTIBILITY TO LEISHMANIA MAJOR INFECTION(2018) GOTO, Hiro; REIS, Luiza; RAMOS-SANCHEZ, Eduardo; PETITTO-ASSIS, Fabricio; NERLAND, Audun; HERNANDEZ-VALLADARES, Maria; SELHEIM, Frode; FLOETER-WINTER, Lucile- Characterization of a Novel Endoplasmic Reticulum Protein Involved in Tubercidin Resistance in Leishmania major(2016) AOKI, Juliana Ide; COELHO, Adriano Cappellazzo; MUXEL, Sandra Marcia; ZAMPIERI, Ricardo Andrade; SANCHEZ, Eduardo Milton Ramos; NERLAND, Audun Helge; FLOETER-WINTER, Lucile Maria; COTRIM, Paulo CesarBackground Tubercidin (TUB) is a toxic adenosine analog with potential antiparasitic activity against Leishmania, with mechanism of action and resistance that are not completely understood. For understanding the mechanisms of action and identifying the potential metabolic pathways affected by this drug, we employed in this study an overexpression/selection approach using TUB for the identification of potential targets, as well as, drug resistance genes in L. major. Although, TUB is toxic to the mammalian host, these findings can provide evidences for a rational drug design based on purine pathway against leishmaniasis. Methodology/Principal findings After transfection of a cosmid genomic library into L. major Friedlin (LmjF) parasites and application of the overexpression/selection method, we identified two cosmids (cosTUB1 and cosTU2) containing two different loci capable of conferring significant levels of TUB resistance. In the cosTUB1 contained a gene encoding NUPM1-like protein, which has been previously described as associated with TUB resistance in L. amazonensis. In the cosTUB2 we identified and characterized a gene encoding a 63 kDa protein that we denoted as tubercidin-resistance protein (TRP). Functional analysis revealed that the transfectants were less susceptible to TUB than LmjF parasites or those transfected with the control vector. In addition, the trp mRNA and protein levels in cosTUB2 transfectants were higher than LmjF. TRP immunolocalization revealed that it was co-localized to the endoplasmic reticulum (ER), a cellular compartment with many functions. In silico predictions indicated that TRP contains only a hypothetical transmembrane domain. Thus, it is likely that TRP is a lumen protein involved in multidrug efflux transport that may be involved in the purine metabolic pathway. Conclusions/Significance This study demonstrated for the first time that TRP is associated with TUB resistance in Leishmania. The next challenge is to determine how TRP mediates TUB resistance and whether purine metabolism is affected by this protein in the parasite. Finally, these findings may be helpful for the development of alternative anti-leishmanial drugs that target purine pathway.