Culture of mouse peritoneal macrophages with mouse serum induces lipid bodies that associate with the parasitophorous vacuole and decrease their microbicidal capacity against Toxoplasma gondii

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.

Produção de peróxido de hidrogênio e atividade de enzimas antioxidantes de macrófagos peritoneais em resposta ao BCG (Bacilo de Calmette-guérin) em modelo murínico de desnutrição proteico-energética / Hydrogen peroxide production and activity of antioxidant enzymes of peritoneal macrophages in response to BCG (Bacillus Calmette-guérin) in a murine model of protein-energy malnutrition

units of BCG (Bacillus Calmette-guérin) and after 7 days they were used in the experiments. We evaluated the complete blood count, peritoneal cellularity and hydrogen peroxide production, besides the activities of glutathione peroxidase, superoxide dismutase and catalase in peritoneal macrophages stimulated with BCG. Malnourished animals presented anemia, leukopenia and severe reduction of peritoneal cellularity. The production of hydrogen peroxide and the activity of glutathione peroxidase, superoxide dismutase and catalase were found to be significantly lower in macrophages from malnourished animals. These findings suggest that malnourished animals present a deficient response to BCG. These findings may be partly responsible for a decrease in the bactericidal and fungicidal activities observed in the malnourished mice. These data lead us to infer that the nutritional status interferes with the activation of macrophages and with the capacity tomount an immune response.Protein-energy malnutrition (PEM) modifies resistance to infection, impairing a number of physiological processes, changing specific and nonspecific immune responses. Macrophages, which are directly involved in several aspects of immunity, may have their functions altered in the malnourishment condition, possibly playing a significant role in the immune deficiency observed in malnourished individuals. Two-month-old male Swiss mice were induced to PEM with a low-protein diet containing 4% protein as compared to 20% protein in the control diet. When the experimental group had lost about 20% of their original body weight the animals from both groups received intraperitoneal injections of 10

unidades de BCG (Bacilo de Calmetteguérin), por vía intraperitoneal, y después de 7 días los animales fueron sacrificados para evaluación de diversos índices: hemograma, celularidad peritoneal, la producción deperóxido de hidrógeno y las actividades glutatión peroxidada, superóxido dismutasa, y catalasa en macrófagos peritonea les estimulados con BCG. Los animales subalimentados presentaron anemia, leucopenia y reducción de la celularidad peritoneal. La producción de peróxido de hidrógeno y la actividad de las enzimas glutatión peroxidada, superóxido dismutasa, y catalasa fue más baja en macrófagos de animales desnutridos. Los resultados sugieren que los ratos desnutridos presentan una respuesta deficiente a BCG lo que explica en parte la disminución de la actividad bactericida y fungicida observada en animales desnutridos. Estos resultados permiten deducir que el estado nutricional interfiere en la actividad de los macrófagos y en su capacidadde respuesta inmunológica.La desnutrición proteico-energética modifica la resistencia a infecciones, alterando diversos procesos fisiológicos, mudando la capacidad de respuesta inmune, específica y no específica. Los macrófagos, células implicadas directamente en varios aspectos de la inmunidad, pueden tener sus funciones alteradas en condiciones de desnutrición desempeñando posiblemente un papel significativo en la deficiencia inmune observada en individuos desnutridos. En este estudio se utilizaron ratos Swiss machos, de 2 meses de edad, en los cuales fue inducida desnutrición proteico-energética por mediode una dieta que contenía 4% de proteína. El grupo control recibió una dieta estándar con 20% de proteína. Cuando el grupo experimental presentó una pérdida de 20% desu peso corporal original, se le administraron 10

unidades de BCG (Bacilo de Calmetteguérin) e após 7 dias foram sacrificados e utilizados nos experimentos. Avaliamos o hemograma, a celularidade peritoneal assim como a produção de peróxido de hidrogênio e a atividade da glutationa peroxidase, superóxido dismutase e catalase em resposta ao BCG em macrófagos peritoneais. Os animais desnutridos apresentaram anemia, leucopenia e a redução severa da celularidade peritoneal. A produção de peróxido de hidrogênio e a atividade das enzimas glutationa peroxidase, super óxido dismutase e catalase foi significativamente menor nos macrófagos de animais desnutridos. Estes resultados sugerem que os animais desnutridos apresentem uma resposta deficiente ao BCG, e que, em parte, podem explicar a diminuição nas atividades bactericidas e fungicidas observadas em animais desnutridos. Estes dados permitem deduzir que o estado nutricional interfere na ativação dos macrófagos e na sua capacidadede resposta imune.A desnutrição proteico-energética (DPE) altera a capacidade de resistência à infecção, alterando diversos processos fisiológicos, mudando a capacidade de respostas imunes específicas e não específicas. Os macrófagos são células envolvidas diretamente em diversos aspectos da imunidade, podem ter suas funções alteradas em condições de desnutrição desempenhando, possivelmente, um papel significativo na imunodeficiência observada nesses indivíduos. Camundongos Swiss, machos, de dois meses de idade, foram induzidos a DPE com uma dieta contendo baixa concentração deproteína (4%) em comparação à dieta controle (20%). Quando o grupo experimental perdeu aproximadamente 20% de seu peso corpóreo original, estes foram considerados aptos aos experimentos. Animais de ambos os grupos receberam injeção intraperitoneal contendo10

Enumeration of macrophage carbohydrates in protein-deficient rats: relation to cell surface properties.

In order to study the effect of protein malnutrition on macrophage glycoproteins the carbohydrate composition of peritoneal macrophages from protein-deficient rats has been studied by paper chromatography and HPLC. The results show that the carbohydrate content of resident cells recovered from protein-deficient group was significantly greater than control and decreased on prolonged incubation. In the protein-deficient samples there was a significant decrease in the content of galactose, fucose and galactosamine known to be binding to specific ligands and increase in glucose and mannosamine. In both control and deficient groups, thioglycollate (TG) elicitation resulted in higher total sialic acid content. Prolonged incubation (18 hr) caused an elevation of sialic acid levels in the resident cells, whereas a drastic reduction was observed in the TG elicited cells. In the protein-fed (20%) group, the cell surface sialic acid which contributes to the negative charge of the cells, reduced significantly on culturing the TG cells but not the resident cells. In the protein-deficient group, this effect was seen in the resident cells also; in the TG cells the cell surface sialic acid was significantly low at the isolation stage suggesting that these cells had become comparatively more positively charged in vivo itself. This observed reduction could be correlated to the enhanced sialidase levels in these cells. These protein deficiency related changes in the carbohydrate composition of macrophages could lead to modification of their receptor activity and charge related functions.