Respiratory Epithelial Cells: More Than Just a Physical Barrier to Fungal Infections.

The respiratory epithelium is highly complex, and its composition varies along the conducting airways and alveoli. In addition to their primary function in maintaining the respiratory barrier and lung homeostasis for gas exchange, epithelial cells interact with inhaled pathogens, which can manipulate cell signaling pathways, promoting adhesion to these cells or hosting tissue invasion. Moreover, pathogens (or their products) can induce the secretion of chemokines and cytokines by epithelial cells, and in this way, these host cells communicate with the immune system, modulating host defenses and inflammatory outcomes.

Histoplasma capsulatum chemotypes I and II induce IL-8 secretion in lung epithelial cells in distinct manners.

The cell wall is one of the most important structures of pathogenic fungi, enabling initial interaction with the host and consequent modulation of immunological responses. Over the years, some researchers have shown that cell wall components of Histoplasma capsulatum vary among fungal isolates, and one of the major differences is the presence or absence of α-(1,3)-glucan, classifying wild-type fungi as chemotypes II or I, respectively. The present work shows that an isolate of H.

A tiered approach to assess effects of diclofenac on the brown mussel Perna perna: A contribution to characterize the hazard.

Pharmaceutical discharges into the aquatic ecosystem are of environmental concern and sewage treatment plants (STPs) have been pointed out as the major source of these compounds to coastal zones, where oceanic disposal of sewage occurs through submarine outfalls. Diclofenac (DCF) is one of the most frequently detected pharmaceuticals in water, but little is known about the effects on marine organisms. In this study, we employed a tiered approach involving the determination of environmental concentrations of DCF in marine water and the adverse biological effects for fertilization, embryo-larval development and biomarker responses of the mussel Perna perna.

Inositol Phosphorylceramide: Distinctive Sphingoid Base Composition.

Inositol phosphorylceramide (IPC), the major sphingolipid in the genus but not found in mammals, is considered a potentially useful target for chemotherapy against leishmaniasis. is endemic in Latin America and causes American tegumentary leishmaniasis. We demonstrated that IPCs are localized internally in parasites, using a specific monoclonal antibody.

Structural diversity and biological significance of glycosphingolipids in pathogenic and opportunistic fungi.

Glycosphingolipids (GSLs) are ubiquitous membrane components and have key roles in biological systems, acting as second messengers or modulators of signal transduction by affecting several events, ranging from cell adhesion, cell growth, cell motility, regulation of apoptosis and cell cycle. Over the last 20 years our laboratory and other research groups determined the glycan and ceramide structures of more than 20 GSLs from several pathogenic/opportunistic fungi, using a combination of gas chromatography, mass spectrometry, nuclear magnetic resonance as well as other immunochemical and biochemical techniques. Fungal GSLs can be divided in two major classes: neutral GSLs, galactosyl- and glucosylceramide (GlcCer), and acidic GSLs, the glycosylinositol-phosphorylceramides (GIPCs).

Glycolipid sensing and innate immunity in paracoccidioidomycosis.

Distinct glycolipid profiles are described in microorganisms, which have been shown to modulate the innate immune system. We tested the hypothesis that glycosphingolipids from Paracoccidioides brasiliensis have immunomodulatory properties on monocytes and dendritic cells of two groups of healthy individuals, one cured of paracoccidioidomycosis in the past (CUR-I) and the other nonexposed to P. brasiliensis (HNE-I).

Myriocin, a serine palmitoyltransferase inhibitor, blocks cytokinesis in Leishmania (Viannia) braziliensis promastigotes.

We studied the effect of myriocin, an inhibitor of serine palmitoyltransferase, on cultured Leishmania (Viannia) braziliensis promastigotes. Myriocin significantly reduced synthesis of inositol phosphorylceramide, the major sphingolipid expressed in promastigotes as characterized by thin layer chromatography and electrospray ionization mass spectrometry. Log-phase promastigotes treated with 1 μM myriocin showed a 52% reduction in growth rate and morphological alterations such as more rounded shape and shorter flagellum.

The impaired viability of prostate cancer cell lines by the recombinant plant kallikrein inhibitor.

Background: Kallikreins play a pivotal role in establishing prostate cancer.

Results: In contrast to the classical Kunitz plant inhibitor SbTI, the recombinant kallikrein inhibitor (rBbKIm) led to prostate cancer cell death, whereas fibroblast viability was not affected.

Conclusion: rBbKIm shows selective cytotoxic effect and angiogenesis inhibition against prostate cancer cells.

Paracoccidioides brasiliensis induces secretion of IL-6 and IL-8 by lung epithelial cells. Modulation of host cytokine levels by fungal proteases.

Paracoccidioides brasiliensis is a pathogenic, dimorphic fungus that causes paracoccidioidomycosis, a systemic human mycosis that is highly prevalent in Latin America. In this study, we demonstrated that P. brasiliensis yeasts induced interleukin (IL)-8 and IL-6 secretion by human lung epithelial A549 cells.

Membrane microdomain components of Histoplasma capsulatum yeast forms, and their role in alveolar macrophage infectivity.

Analysis of membrane lipids of Histoplasma capsulatum showed that ~40% of fungal ergosterol is present in membrane microdomain fractions resistant to treatment with non-ionic detergent at 4°C. Specific proteins were also enriched in these fractions, particularly Pma1p a yeast microdomain protein marker (a plasma membrane proton ATPase), a 30kDa laminin-binding protein, and a 50kDa protein recognized by anti-α5-integrin antibody. To better understand the role of ergosterol-dependent microdomains in fungal biology and pathogenicity, H.

Phospholipase-D activity and inflammatory response induced by brown spider dermonecrotic toxin: endothelial cell membrane phospholipids as targets for toxicity.

Brown spider dermonecrotic toxins (phospholipases-D) are the most well-characterized biochemical constituents of Loxosceles spp. venom. Recombinant forms are capable of reproducing most cutaneous and systemic manifestations such as dermonecrotic lesions, hematological disorders, and renal failure.

Effect of anti-glycosphingolipid monoclonal antibodies in pathogenic fungal growth and differentiation. Characterization of monoclonal antibody MEST-3 directed to Manpalpha1-->3Manpalpha1-->2IPC.

Background: Studies carried out during the 1990's demonstrated the presence of fungal glycoinositol phosphorylceramides (GIPCs) with unique structures, some of them showed reactivity with sera of patients with histoplasmosis, paracoccidioidomycosis or aspergillosis. It was also observed that fungal GIPCs were able to inhibit T lymphocyte proliferation "in vitro", and studies regarding the importance of these molecules to fungal survival showed that many species of fungi are vulnerable to inhibitors of sphingolipid biosynthesis.

Results: In this paper, we describe a detailed characterization of an IgG2a monoclonal antibody (mAb), termed MEST-3, directed to the Paracoccidioides brasiliensis glycolipid antigen Pb-2 (Manpalpha1-->3Manpalpha1-->2IPC).

Current relevance of fungal and trypanosomatid glycolipids and sphingolipids: studies defining structures conspicuously absent in mammals.

Recently, glycosphingolipids have been attracting attention due to their role on biological systems as second messengers or modulators of signal transduction, affecting several events, which range from apoptosis to regulation of the cell cycle. In pathogenic fungi, glycolipids are expressed in two classes: neutral monohexosylceramides (glucosyl-or galactosylceramide) and acidic glycosylinositol phosphorylceramides (the latter class carries longer glycan chains). It is worth to mention that monohexosylceramides exhibit significant structural differences in their lipid moieties compared to their mammalian counterparts, whereas the glycosylinositol phosphorylceramides exhibit remarkable structural differences in their carbohydrate moieties in comparison to mammal glycosphingolipids counterpart.

Modulation of the type I hypersensitivity late phase reaction to OVA by Propionibacterium acnes-soluble polysaccharide.

Late phase reaction (LPR) of immediate hypersensitivity is a Th2 response characterized by eosinophil recruitment and related to allergic asthma pathogenesis. Several strategies were developed trying to control the tissue damage observed in this reaction. Recently, we verified that killed Propionibacterium acnes (P.

Interaction of epithelial cell membrane rafts with Paracoccidioides brasiliensis leads to fungal adhesion and Src-family kinase activation.

Membrane rafts are cholesterol- and sphingolipid-enriched cell membrane domains, which are ubiquitous in mammals and play an essential role in different cellular functions, including host cell-pathogen interaction. In this work, by using several approaches, we demonstrated the involvement of epithelial cell membrane rafts in adhesion process of the pathogenic fungus Paracoccidioides brasiliensis. This conclusion was supported by the localization of ganglioside GM1, a membrane raft marker, at P.

Trypanosomatid and fungal glycolipids and sphingolipids as infectivity factors and potential targets for development of new therapeutic strategies.

Several (glyco)(sphingo)lipids from different human pathogens have been characterized, and frequently many of these molecules are participating in host-pathogen interaction. In Leishmania (Leishmania) amazonensis, for example, amastigotes present on their surface glycosphingolipids (GSLs) with the structure Galbeta1-3Galalpha, which is recognized by 30 kDa receptor of macrophages. Furthermore, other Leishmania species, such as Leishmania (Leishmania) major and Leishmania (Viannia) braziliensis present glycosylinositolphospholipids (GIPLs) which are involved in Leishmania-macrophage interaction.

Analysis of glycosylinositol phosphorylceramides expressed by the opportunistic mycopathogen Aspergillus fumigatus.

Acidic glycosphingolipid components were extracted from the opportunistic mycopathogen Aspergillus fumigatus and identified as inositol phosphorylceramide and glycosylinositol phosphorylceramides (GIPCs). Using nuclear magnetic resonance sppectroscopy, mass spectrometry, and other techniques, the structures of six major components were elucidated as Ins-P-Cer (Af-0), Manp(alpha1-->3)Manp(alpha1-->2)Ins-P-Cer (Af-2), Manp(alpha1-->2)Manp(alpha1-->3)Manp(alpha1-->2)Ins-P-Cer (Af-3a), Manp(alpha1-->3)[Galf(beta1-->6)]Manp(alpha1-->2)-Ins-P-Cer (Af-3b), Manp(alpha1-->2)-Manp(alpha1-->3)[Galf(beta1-->6)]Manp(alpha1-->2)Ins-P-Cer (Af-4), and Manp(alpha1-->3)Manp(alpha1-->6)GlcpN(alpha1-->2)Ins-P-Cer (Af-3c) (where Ins = myo-inositol and P = phosphodiester). A minor A.

Effect of ganglioside and tetraspanins in microdomains on interaction of integrins with fibroblast growth factor receptor.

The functional interaction ("cross-talk") of integrins with growth factor receptors has become increasingly clear as a basic mechanism in cell biology, defining cell growth, adhesion, and motility. However, no studies have addressed the microdomains in which such interaction takes place nor the effect of gangliosides and tetraspanins (TSPs) on such interaction. Growth of human embryonal WI38 fibroblasts is highly dependent on fibroblast growth factor (FGF) and its receptor (FGFR), stably associated with ganglioside GM3 and TSPs CD9 and CD81 in the ganglioside-enriched microdomain.

Sphingosine-dependent apoptosis: a unified concept based on multiple mechanisms operating in concert.

Exposure of 3T3/A31 cells to serum-free medium, one type of apoptotic stimulus, causes a rapid increase in the sphingosine (Sph) level, which initiates a series of processes: (i) activation of caspase 3 through an enhanced "cascade" of caspases, (ii) release of the C-terminal-half kinase domain of PKCdelta (PKCdelta KD) by caspase 3, and (iii) activation of Sph-dependent kinase 1 (SDK1), which was previously identified as PKCdelta KD. The activation of caspase 3 and release of PKCdelta KD are inhibited strongly by the incubation of cells with the ceramidase inhibitor D-erythro-2-tetradecanoylamino-1-phenyl-1-propanol and, to a much lesser extent, by L-cycloserine, an inhibitor of de novo ceramide synthesis. Exogenous addition of Sph or N,N-dimethyl-Sph to U937 cells causes caspase 3 activation and release of PKCdelta KD (SDK1), leading to apoptosis.

Cell growth regulation through GM3-enriched microdomain (glycosynapse) in human lung embryonal fibroblast WI38 and its oncogenic transformant VA13.

Cell growth control mechanisms were studied based on organization of components in glycosphingolipid-enriched microdomain (GEM) in WI38 cells versus their oncogenic transformant VA13 cells. Levels of fibroblast growth factor receptor (FGFR) and cSrc were 4 times and 2-3 times higher, respectively, in VA13 than in WI38 GEM, whereas the level of tetraspanin CD9/CD81 was 3-5 times higher in WI38 than in VA13 GEM. Csk, the physiological inhibitor of cSrc, was present in WI38 but not in VA13 GEM.

Role of beta-D-galactofuranose in Leishmania major macrophage invasion.

The role of glycosylinositol phospholipid 1 (GIPL-1) of Leishmania (Leishmania) major in the interaction of promastigotes and amastigotes with macrophages was analyzed. Monoclonal antibody MEST-1, which recognizes glycolipids containing terminal galactofuranose (Galf) residues (E. Suzuki, M.

Disruption of the glucosylceramide biosynthetic pathway in Aspergillus nidulans and Aspergillus fumigatus by inhibitors of UDP-Glc:ceramide glucosyltransferase strongly affects spore germination, cell cycle, and hyphal growth.

The opportunistic mycopathogen Aspergillus fumigatus expresses both glucosylceramide and galactosylceramide (GlcCer and GalCer), but their functional significance in Aspergillus species is unknown. We here identified and characterized a GlcCer from Aspergillus nidulans, a non-pathogenic model fungus. Involvement of GlcCer in fungal development was tested on both species using a family of compounds known to inhibit GlcCer synthase in mammals.