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Extracellular vesicles (EVs) have a significant impact on the pathophysiological processes associated with various diseases such as tumors, inflammation, and infection. They exhibit molecular, biochemical, and entry control characteristics similar to viral infections. Viruses, on the other hand, depend on host metabolic machineries to fulfill their biosynthetic requirements. Due to potential advantages such as biocompatibility, biodegradation, and efficient immune activation, EVs have emerged as potential therapeutic targets against the SARS-CoV-2 infection. Studies on COVID-19 patients have shown that they frequently have dysregulated lipid profiles, which are associated with an increased risk of severe repercussions. Lipid droplets (LDs) serve as organelles with significant roles in lipid metabolism and energy homeostasis as well as having a wide range of functions in infections. The down-modulation of lipids, such as sphingolipid ceramide and eicosanoids, or of the transcriptional factors involved in lipogenesis seem to inhibit the viral multiplication, suggesting their involvement in the virus replication and pathogenesis as well as highlighting their potential as targets for drug development. Hence, this review focuses on the role of modulation of lipid metabolism and EVs in the mechanism of immune system evasion during SARS-CoV-2 infection and explores the therapeutic potential of EVs as well as application for delivering therapeutic substances to mitigate viral infections.
Assuntos
COVID-19 , Vesículas Extracelulares , Humanos , Metabolismo dos Lipídeos , SARS-CoV-2 , LipogêneseRESUMO
Sporotrichosis is a fungal infection caused by Sporothrix species, with Sporothrix brasiliensis as a prevalent pathogen in Latin America. Despite its clinical importance, the virulence factors of S. brasiliensis and their impact on the pathogenesis of sporotrichosis are still poorly understood. This study evaluated the morphostructural plasticity of S. brasiliensis, a fungus that causes sporotrichosis. Three cell surface characteristics, namely cell surface hydrophobicity, Zeta potential, and conductance, were assessed. Biofilm formation was also analyzed, with measurements taken for biomass, extracellular matrix, and metabolic activity. In addition, other potential and poorly studied characteristics correlated with virulence such as lipid bodies, chitin, and cell size were evaluated. The results revealed that the major phenotsypic features associated with fungal virulence in the studied S. brasiliensis strains were chitin, lipid bodies, and conductance. The dendrogram clustered the strains based on their overall similarity in the production of these factors. Correlation analyses showed that hydrophobicity was strongly linked to the production of biomass and extracellular matrix, while there was a weaker association between Zeta potential and size, and lipid bodies and chitin. This study provides valuable insights into the virulence factors of S. brasiliensis and their potential role in the pathogenesis of sporotrichosis.
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Paubrasilia echinata (brazilwood) is an endangered native tree from the Brazilian Atlantic Forest whose seeds tolerate maturation drying, but, unlike classic orthodox seeds, they quickly lose viability after shedding. This work analyzed the biochemical and ultrastructural changes during the maturation of brazilwood seeds, with particular attention to the cell walls and organization of the cellular components. The physiological seed maturity was accompanied by increased starch content and decreased soluble sugars. Arabinose increased considerably and was the predominant cell-wall sugar during maturation, suggesting a rise in arabinans that contribute to greater cell wall flexibility. This increase was consistent with the cell wall infolding observed in the hypocotyl axis and cotyledons during the maturation of brazilwood seeds. Ultrastructural analyses showed changes in the number and distribution of protein bodies and amyloplasts and the reorganization of lipid droplets into large drops or masses during seed desiccation. Our findings demonstrate that brazilwood seeds behave like other orthodox seeds during maturation, performing the cell wall and metabolic changes before the major decline in the seed water content. However, the high vacuolization and reorganization of lipid bodies observed at 65 DAA suggest that cell deterioration occurs to some extent at the end of the maturation period and could be responsible for reducing the longevity of the brazilwood dried seeds.
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Caesalpinia , Parede Celular , Dessecação , Germinação/fisiologia , Sementes/químicaRESUMO
Lipid droplets (LDs; lipid bodies) are intracellular sites of lipid storage and metabolism present in all cell types. Eukaryotic LDs are involved in eicosanoid production during several inflammatory conditions, including infection by protozoan parasites. In parasites, LDs play a role in the acquisition of cholesterol and other neutral lipids from the host. The number of LDs increases during parasite differentiation, and the biogenesis of these organelles use specific signaling pathways involving protein kinases. In addition, LDs are important in cellular protection against lipotoxicity. Recently, these organelles have been implicated in eicosanoid and specialised lipid metabolism. In this article, we revise the main functions of protozoan parasite LDs and discuss future directions in the comprehension of these organelles in the context of pathogen virulence.
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Lipid droplets (lipid bodies, LDs) are dynamic organelles that have important roles in regulating lipid metabolism, energy homeostasis, cell signaling, membrane trafficking, and inflammation. LD biogenesis, composition, and functions are highly regulated and may vary according to the stimuli, cell type, activation state, and inflammatory environment. Increased cytoplasmic LDs are frequently observed in leukocytes and other cells in a number of infectious diseases. Accumulating evidence reveals LDs participation in fundamental mechanisms of host-pathogen interactions, including cell signaling and immunity. LDs are sources of eicosanoid production, and may participate in different aspects of innate signaling and antigen presentation. In addition, intracellular pathogens evolved mechanisms to subvert host metabolism and may use host LDs, as ways of immune evasion and nutrients source. Here, we review mechanisms of LDs biogenesis and their contributions to the infection progress, and discuss the latest discoveries on mechanisms and pathways involving LDs roles as regulators of the immune response to protozoan infection.
Assuntos
Interações Hospedeiro-Parasita , Gotículas Lipídicas/imunologia , Metabolismo dos Lipídeos , Lipídeos/biossíntese , Biogênese de Organelas , Animais , Apresentação de Antígeno , Homeostase , Interações Hospedeiro-Patógeno , Humanos , Camundongos , Transporte Proteico , Infecções por Protozoários/imunologia , Transdução de Sinais/imunologiaRESUMO
During the onset of Trypanosoma cruzi infection, an effective immune response is necessary to control parasite replication and ensure host survival. Macrophages have a central role in innate immunity, acting as an important trypanocidal cell and triggering the adaptive immune response through antigen presentation and cytokine production. However, T. cruzi displays immune evasion mechanisms that allow infection and replication in macrophages, favoring its chronic persistence. One potential mechanism is the release of T. cruzi strain Y extracellular vesicle (EV Y), which participate in intracellular communication by carrying functional molecules that signal host cells and can modulate the immune response. The present work aimed to evaluate immune modulation by EV Y in C57BL/6 mice, a prototype resistant to infection by T. cruzi strain Y, and the effects of direct EV Y stimulation of macrophages in vitro. EV Y inoculation in mice prior to T. cruzi infection resulted in increased parasitemia, elevated cardiac parasitism, decreased plasma nitric oxide (NO), reduced NO production by spleen cells, and modulation of cytokine production, with a reduction in TNF-α in plasma and decreased production of TNF-α and IL-6 by spleen cells from infected animals. In vitro assays using bone marrow-derived macrophages showed that stimulation with EV Y prior to infection by T. cruzi increased the parasite internalization rate and release of infective trypomastigotes by these cells. In this same scenario, EV Y induced lipid body formation and prostaglandin E2 (PGE2) production by macrophages even in the absence of T. cruzi. In infected macrophages, EV Y decreased production of PGE2 and cytokines TNF-α and IL-6 24 h after infection. These results suggest that EV Y modulates the host response in favor of the parasite and indicates a role for lipid bodies and PGE2 in immune modulation exerted by EVs.
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Doença de Chagas/imunologia , Vesículas Extracelulares/imunologia , Interações Hospedeiro-Parasita/imunologia , Macrófagos Peritoneais/imunologia , Trypanosoma cruzi/imunologia , Animais , Doença de Chagas/parasitologia , Chlorocebus aethiops , Dinoprostona/imunologia , Dinoprostona/metabolismo , Modelos Animais de Doenças , Humanos , Evasão da Resposta Imune , Gotículas Lipídicas/imunologia , Gotículas Lipídicas/metabolismo , Ativação de Macrófagos/imunologia , Macrófagos Peritoneais/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Baço/citologia , Baço/imunologia , Trypanosoma cruzi/metabolismo , Células VeroRESUMO
The inflammatory process plays a major role in the prognosis of dengue. In this context, the eicosanoids may have considerable influence on the regulation of the Dengue virus-induced inflammatory process. To quantify the molecules involved in the cyclooxygenase and lipoxygenase pathways during Dengue virus infection, plasma levels of thromboxane A2, prostaglandin E2 and leukotriene B4; mRNA levels of thromboxane A2 synthase, prostaglandin E2 synthase, leukotriene A4 hydrolase, cyclooxygenase-2 and 5-lipoxygenase; and the levels of lipid bodies in peripheral blood leukocytes collected from IgM-positive and IgM-negative volunteers with mild dengue, and non-infected volunteers, were evaluated. Dengue virus infection increases the levels of thromboxane A2 in IgM-positive individuals as well as the amount of lipid bodies in monocytes in IgM-negative individuals. We suggest that increased levels of thromboxane A2 in IgM-positive individuals plays a protective role against the development of severe symptoms of dengue, such as vascular leakage.
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Vírus da Dengue/imunologia , Dengue/sangue , Dengue/imunologia , Imunoglobulina M/imunologia , Tromboxano A2/sangue , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos Transversais , Ciclo-Oxigenase 2/sangue , Ciclo-Oxigenase 2/genética , Dengue/diagnóstico , Dengue/virologia , Feminino , Humanos , Imunoglobulina M/sangue , Leucócitos/imunologia , Leucócitos/metabolismo , Masculino , Pessoa de Meia-Idade , Monócitos/imunologia , Monócitos/metabolismo , Tromboxano A2/genética , Carga Viral , Adulto JovemRESUMO
BACKGROUND: In cancer cells, autophagy can act as both tumor suppressor, when autophagic event eliminates cellular contends which exceeds the cellular capacity of regenerate promoting cell death, and as a pro-survival agent removing defective organelles and proteins and helping well-established tumors to maintain an accelerated metabolic state while still dealing with harsh conditions, such as inflammation. Many pathways can coordinate the autophagic process and one of them involves the transcription factors called PPARs, which also regulate cellular differentiation, proliferation and survival. The PPARγ activation and autophagy initiation seems to be interrelated in a variety of cell types. METHODS: Caco-2 cells were submitted to treatment with autophagy and PPARγ modulators and the relationship between both pathways was determined by western blotting and confocal microscopy. The effects of such modulations on Caco-2 cells, such as lipid bodies biogenesis, cell death, proliferation, cell cycle, ROS production and cancer stem cells profiling were analyzed by flow cytometry. RESULTS: PPARγ and autophagy pathways seem to be overlap in Caco-2 cells, modulating each other in different ways and determining the lipid bodies biogenesis. In general, inhibition of autophagy by 3-MA leaded to reduced cell proliferation, cell cycle arrest and, ultimately, cell death by apoptosis. In agreement with these results, ROS production was increased in 3-MA treated cells. Autophagy also seems to play an important role in cancer stem cells profiling. Rapamycin and 3-MA induced epithelial and mesenchymal phenotypes, respectively. CONCLUSIONS: This study helps to elucidate in which way the induction or inhibition of these pathways regulate each other and affect cellular properties, such as ROS production, lipid bodies biogenesis and cell survive. We also consolidate autophagy as a key factor for colorectal cancer cells survival in vitro, pointing out a potential side effect of autophagic inhibition as a therapeutic application for this disease and demonstrate a novel regulation of PPARγ expression by inhibition of PI3K III.
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Lipid bodies (LBs) are intracellular accumulations of neutral lipids surrounded by a single membrane. These organelles are involved in the production of eicosanoids, which modulate immunity by either promoting or dampening inflammatory responses. Leishmania infantum, the etiological agent of visceral leishmaniasis in Brazil, is an intracellular parasite that causes disease by suppressing macrophage microbicidal responses. C57BL/6 mouse bone marrow-derived macrophages infected with L. infantum strain LcJ had higher numbers of LB+ cells (P<.0001) and total LBs than noninfected cultures. Large (>3 µm) LBs were present inside parasitophorous vacuoles (PVs). These results contrast with those of L. infantum-infected BALB/c macrophages, in which the only LBs are derived from parasite, not macrophage origin. Increased LBs in C57BL/6 macrophages in close association with parasites would position host LBs where they could modulate L. infantum infection. These results imply a potential influence of the host genetics on the role of LBs in host-pathogen interactions. Overall, our data support a model in which the expression, and the role of LBs upon infection, ultimately depends on the specific combination of host-pathogen interactions.
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Leishmania infantum/imunologia , Leishmaniose Visceral/imunologia , Gotículas Lipídicas/metabolismo , Macrófagos/microbiologia , Animais , Brasil , Feminino , Leishmaniose Visceral/patologia , Macrófagos/imunologia , Macrófagos/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BLRESUMO
Proinflammatory responses are associated with the severity of cerebral malaria. NO, H2O2, eicosanoid and PPAR-γ are involved in proinflammatory responses, but regulation of these factors is unclear in malaria. This work aimed to compare the expression of eicosanoid-forming-enzymes in cerebral malaria-susceptible CBA and C57BL/6 and -resistant BALB/c mice. Mice were infected with Plasmodium berghei ANKA, and the survival rates and parasitemia curves were assessed. On the sixth day post-infection, cyclooxygenase-2 and 5-lipoxygenase in brain sections were assessed by immunohistochemistry, and, NO, H2O2, lipid bodies, and PPAR-γ expression were assessed in peritoneal macrophages. The C57BL/6 had more severe disease with a lower survival time, higher parasitemia and lower production of plasmodicidal NO and H2O2 molecules than BALB/c. Enhanced COX-2 and 5-LOX expression were observed in brain tissue cells and vessels from C57BL/6 mice, and these mice expressed higher constitutive PPAR-γ levels. There was no translocation of PPAR-γ from cytoplasm to nucleus in macrophages from these mice. CBA mice had enhanced COX-2 expression in brain tissue cells and vessels and also lacked PPAR-γ cytoplasm-to-nucleus translocation. The resistant BALB/c mice presented higher survival time, lower parasitemia and higher NO and H2O2 production on the sixth day post-infection. These mice did not express either COX-2 or 5-LOX in brain tissue cells and vessels. Our data showed that besides the high parasite burden and lack of microbicidal molecules, an imbalance with high COX-2 and 5-LOX eicosanoid expression and a lack of regulatory PPAR-γ cytoplasm-to-nucleus translocation in macrophages were observed in mice that develop cerebral malaria.
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Araquidonato 5-Lipoxigenase/metabolismo , Ciclo-Oxigenase 2/metabolismo , Suscetibilidade a Doenças , Gotículas Lipídicas/metabolismo , Malária Cerebral/metabolismo , PPAR gama/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Animais , Araquidonato 5-Lipoxigenase/genética , Encéfalo/metabolismo , Encéfalo/parasitologia , Encéfalo/patologia , Ciclo-Oxigenase 2/genética , Expressão Gênica , Macrófagos Peritoneais/metabolismo , Malária Cerebral/mortalidade , Malária Cerebral/parasitologia , Malária Cerebral/patologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos CBA , Microglia/metabolismo , Óxido Nítrico/metabolismo , Nitritos/metabolismo , Plasmodium berghei , Transporte ProteicoRESUMO
Chlamydomonas acidophila LAFIC-004 is an acidophilic strain of green microalgae isolated from coal mining drainage. In the present work, this strain was cultivated in acidic medium (pH 3.6) under phototrophic, mixotrophic, and heterotrophic regimes to determine the best condition for growth and lipid production, simultaneously assessing possible morphological and ultrastructural alterations in the cells. For heterotrophic and mixotrophic treatments, two organic carbon sources were tested: 1 % glucose and 1 % sodium acetate. Lipid content and fatty acid profiles were only determined in phototrophic condition. The higher growth rates were achieved in phototrophic conditions, varying from 0.18 to 0.82 day-1. Glucose did not result in significant growth increase in either mixotrophic or heterotrophic conditions, and acetate proved to be toxic to the strain in both conditions. Oil content under phototrophic condition was 15.9 % at exponential growth phase and increased to 54.63 % at stationary phase. Based on cell morphology (flow cytometry and light microscopy) and ultrastructure (transmission electron microscopy), similar characteristics were observed between phototrophic and mixotrophic conditions with glucose evidencing many lipid bodies, starch granules, and intense fluorescence. Under the tested conditions, mixotrophic and heterotrophic modes did not result in increased neutral lipid fluorescence. It can be concluded that the strain is a promising lipid producer when grown until stationary phase in acidic medium and under a phototrophic regime, presenting a fatty acid profile suitable for biodiesel production. The ability to grow this strain in acidic mining residues suggests a potential for bioremediation with production of useful biomass.
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Chlamydomonas/metabolismo , Chlamydomonas/ultraestrutura , Ácidos Graxos/biossíntese , Glucose/metabolismo , Processos Heterotróficos/fisiologia , Processos Fototróficos/fisiologia , Biodegradação Ambiental , Biocombustíveis , Chlamydomonas/crescimento & desenvolvimento , Minas de Carvão , Gotículas Lipídicas/metabolismo , Microalgas/classificação , Microalgas/metabolismo , Microscopia Eletrônica de TransmissãoRESUMO
Rhodococcus opacus PD630 and Rhodococcus jostii RHA1 are oleaginous bacteria able to synthesize and accumulate triacylglycerols (TAG) in lipid bodies (LB). Highly relevant to the structure of LB is a protein homologous to heparin-binding hemagglutinin (HBHA) (called TadA in rhodococci), which is a virulence factor found in Mycobacterium tuberculosis. HBHA is an adhesin involved in binding to non-phagocytic cells and extrapulmonary dissemination. We observed a conserved synteny of three genes encoding a transcriptional regulator (TR), the HBHA protein and a membrane protein (MP) between TAG-accumulating actinobacteria belonging to Rhodococcus, Mycobacterium, Nocardia and Dietzia genera, among others. A 354 bp-intergenic spacing containing a SigF-binding site was found between hbha and the TR genes in M. tuberculosis, which was absent in genomes of other investigated actinobacteria. Analyses of available "omic" information revealed that TadA and TR were co-induced in rhodococci under TAG-accumulating conditions; whereas in M. tuberculosis and Mycobacterium smegmatis, HBHA and TR were regulated independently under stress conditions occurring during infection. We also found differences in protein lengths, domain content and distribution between HBHA and TadA proteins from mycobacteria and rhodococci, which may explain their different roles in cells. Based on the combination of results obtained in model actinobacteria, we hypothesize that HBHA and TadA proteins originated from a common ancestor, but later suffered a process of functional divergence during evolution. Thus, rhodococcal TadA probably has maintained its original role; whereas HBHA may have evolved as a virulence factor in pathogenic mycobacteria.
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Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Evolução Molecular , Lectinas/genética , Lectinas/metabolismo , Mycobacterium tuberculosis/genética , Sequência de Aminoácidos , Proteínas de Bactérias/química , Genômica , Lectinas/química , Filogenia , SinteniaRESUMO
Lipid bodies [lipid droplets (LBs)] are lipid-rich organelles involved in lipid metabolism, signalling and inflammation. Recent findings suggest a role for LBs in host response to infection; however, the potential functions of this organelle in Toxoplasma gondii infection and how it alters macrophage microbicidal capacity during infection are not well understood. Here, we investigated the role of host LBs in T. gondii infection in mouse peritoneal macrophages in vitro. Macrophages cultured with mouse serum (MS) had higher numbers of LBs than those cultured in foetal bovine serum and can function as a model to study the role of LBs during intracellular pathogen infection. LBs were found in association with the parasitophorous vacuole, suggesting that T. gondii may benefit from this lipid source. Moreover, increased numbers of macrophage LBs correlated with high prostaglandin E2 (PGE2) production and decreased nitric oxide (NO) synthesis. Accordingly, LB-enriched macrophages cultured with MS were less efficient at controlling T. gondii growth. Treatment of macrophages cultured with MS with indomethacin, an inhibitor of PGE2 production, increased the microbicidal capacity against T. gondii. Collectively, these results suggest that culture with MS caused a decrease in microbicidal activity of macrophages against T. gondii by increasing PGE2 while lowering NO production.
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Animais , Bovinos , Masculino , Camundongos , Gotículas Lipídicas/parasitologia , Ativação de Macrófagos/fisiologia , Macrófagos Peritoneais/parasitologia , Toxoplasma/fisiologia , Vacúolos/parasitologia , Interações Hospedeiro-Parasita , Indometacina/farmacologia , Gotículas Lipídicas/fisiologia , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Macrófagos Peritoneais/química , Macrófagos Peritoneais/fisiologia , Macrófagos Peritoneais/ultraestrutura , Óxido Nítrico/biossíntese , Cultura Primária de Células , Prostaglandinas E/antagonistas & inibidores , Prostaglandinas E/biossíntese , Vacúolos/fisiologiaRESUMO
In the present work, we analyzed the histochemical aspects of Passiflora edulis seeds reserve mobilization during the first ten days of germination. Our results showed that mainly lipids present in the endosperm are used as a reserve source, and their levels reduce at the same time the radicle protrudes, between the fourth and sixth day of sowing. Furthermore, protein bodies are present in the cotyledons, which are degraded as germination occurs and are almost depleted by the time of radicle protrusion. Starch grains also appear in the late germination period, and it is not clear if there is any reserve wall polysaccharide consumption in the endosperm.(AU)
No presente trabalho analisamos os aspectos histoquímicos da mobilização de reservas das sementes de Passiflora edulis, durante os primeiros dez dias de germinação. Nossos resultados mostraram que principalmente lipídios presentes no endosperma são utilizados como reserva, com o seu nível começando a diminuir ao mesmo tempo em que ocorre a protrusão da radícula, entre o quarto e sexto dia do início da embebição. Corpos proteicos também estão presentes nos cotilédones, e são degradados à medida que ocorre a germinação e são consumidos quase totalmente quando da protrusão da radícula. Grãos de amido também aparecem no período tardio de germinação, e não está claro se há ou não consumo de polissacarídeos de reserva de parede no endosperma.(AU)
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Germinação/fisiologia , Passiflora/embriologia , Sementes/química , Cotilédone/fisiologia , Endosperma/fisiologia , Histocitoquímica , Passiflora/química , Proteínas de Plantas/fisiologia , Proteínas de Armazenamento de Sementes , Sementes/embriologiaRESUMO
In the present work, we analyzed the histochemical aspects of Passiflora edulis seeds reserve mobilization during the first ten days of germination. Our results showed that mainly lipids present in the endosperm are used as a reserve source, and their levels reduce at the same time the radicle protrudes, between the fourth and sixth day of sowing. Furthermore, protein bodies are present in the cotyledons, which are degraded as germination occurs and are almost depleted by the time of radicle protrusion. Starch grains also appear in the late germination period, and it is not clear if there is any reserve wall polysaccharide consumption in the endosperm.
No presente trabalho analisamos os aspectos histoquímicos da mobilização de reservas das sementes de Passiflora edulis, durante os primeiros dez dias de germinação. Nossos resultados mostraram que principalmente lipídios presentes no endosperma são utilizados como reserva, com o seu nível começando a diminuir ao mesmo tempo em que ocorre a protrusão da radícula, entre o quarto e sexto dia do início da embebição. Corpos proteicos também estão presentes nos cotilédones, e são degradados à medida que ocorre a germinação e são consumidos quase totalmente quando da protrusão da radícula. Grãos de amido também aparecem no período tardio de germinação, e não está claro se há ou não consumo de polissacarídeos de reserva de parede no endosperma.