RESUMO
Mast cells play a central role in the early clearance of the intestinal parasite Giardia lamblia. In a previous study, we reported that G. lamblia live trophozoites or trophozoite-derived total soluble extract induced direct activation (IgE-independent) of mast cells and release of IL-6 and TNF-α. To identify the Giardia molecules and the mast cell receptors involved in this activation, trophozoite-derived total soluble proteins separated into three fractions (F1-F3) were evaluated for its ability to activate mast cells in vitro. F2 activated mast cells in a greater extent than F1 and F3. Furthermore, F2 induced the release of IL-6 and TNF-α by mast cells. TLR2 and TLR4 expression increased slightly after mast cell stimulation with either F2 or total soluble extract; however, these receptors were not involved in F2 or total soluble extract-induced proinflammatory cytokine production. Proteins present in F2 as unique and high-intensity bands identified by liquid chromatography coupled with tandem mass spectrometry, include molecules with important biological activities such as enolase and arginine deiminase (ADI). Recombinant ADI and enolase were tested for their ability to activate mast cells, but only ADI induced a significant release of IL-6 and TNF-α. ADI product, citrulline but not ammonium, also induced mast cell release of TNF-α. Interestingly, recombinant ADI still stimulated the secretion of TNF-α by mast cells in a arginine-free medium, although in a lower extend that in the presence of arginine, indicating that either ADI itself can stimulate mast cells or through its metabolic product, citrulline.
Assuntos
Extratos Celulares/imunologia , Citrulina/imunologia , Giardia lamblia/imunologia , Hidrolases/imunologia , Mastócitos/imunologia , Animais , Arginina , Linhagem Celular , Giardíase/imunologia , Giardíase/parasitologia , Interleucina-6/imunologia , Interleucina-6/metabolismo , Fosfopiruvato Hidratase/metabolismo , Ratos , Ratos Sprague-Dawley , Receptor 2 Toll-Like/imunologia , Receptor 4 Toll-Like/imunologia , Trofozoítos/imunologia , Fator de Necrose Tumoral alfa/imunologia , Fator de Necrose Tumoral alfa/metabolismoRESUMO
Se sintetizó una serie de sólidosnanoestructurados obtenidos de laintercalación de nanopartículas de TiO2y Fe-TiO2 en los espacios interlaminaresde un mineral de arcilla esmectítico. Losnuevos materiales se prepararon mediantela modificación simultánea de dos mineralesnaturales: bentonita e ilmenita. Los materialesobtenidos se caracterizaron por fluorescenciade rayos X (FRX), espectroscopia infrarroja(IR), difracción de rayos X (DRX),microscopia electrónica de barrido (SEM)y sortometría de nitrógeno. Los resultadosdel análisis químico (FRX) confirmaronclaramente la incorporación de titanio y dehierro en los materiales sintetizados. Losanálisis por DRX, SEM y sortometría denitrógeno verificaron la modificación delmineral de arcilla por incorporación deespecies de dióxido de titanio y la generaciónde estructuras mesoporosas delaminadas oexfoliadas con incremento en los valores deárea superficial y porosidad controlada.
A set of nanostructured porous solids was synthesized by intercalation of TiO2 and Fe- TiO2 into the interlayer sites of a smectite clay mineral. The new materials were prepared through simultaneous modification of two natural minerals: bentonite and ilmenite. Synthesized materials were characterized by X-ray fluorescence (XRF), infrared spectroscopy (IR), X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and N2-adsorption technique. Results of chemical analysis (XRF) clearly confirmed the incorporation of titanium and iron in the synthesized materials. Modification of clay mineral by incorporation of titanium dioxide species was verified by XRD, SEM and N2- adsorption analyses, showing the formation of mesoporous delaminated structures with increased surface areas and controlled porosity.
Uma serie de sólidos nanoestruturadosforam sintetizados, obtidos pela intercalaçãode nanopartículas de TiO2 e Fe-TiO2 nosespaços interlaminares de um mineralde argila esmectítica. Os novos materiaisforam preparados mediante a modificaçãosimultânea de dois minerais naturais:uma bentonita e uma ilmenita. Osmateriais obtidos foram caracterizadospor fluorescência de raios X (FRX),espectroscopia infra-vermelho (IR), difraçãode raios X (DRX), microscopia eletrônica devarredura (SEM) e sortometria de nitrogênio.Os resultados da análise química (FRX)confirmaram claramente a incorporação detitânio e de ferro nos materiais sintetizados.A análise por DRX, SEM e sortometriade nitrogênio verificaram a modificaçãodo mineral de argila por incorporação deespécies de dióxido de titânio, demonstrandoa geração de estruturas mesoporosasdelaminadas ou esfoliadas com incrementonos valores de área superficial e porosidade controlada.