THE ROLE OF INTERFERON REGULATORY FACTORS IN THE PATHOGENESIS OF EXPERIMENTAL CEREBRAL MALARIA

Ph.DDOCTOR OF PHILOSOPH

Ultrasound-assisted extraction kinetics, fatty acid profile, total phenolic content and antioxidant activity of green solvents extracted passion fruit oil

The main objective of this current work was to evaluate the feasibility of green solvent's application on passion fruit oil extraction. In this study, the effects of green solvent on oil yield, fatty acid profile, oil physicochemical properties, total phenolic content and antioxidant activity associated with extracted oil were compared to those of conventional solvent, hexane application. Therefore, this study may provide supplementary information on previous studies that focused on oil recovery. Oilseeds' proximate composition and the influence of oilseeds-to-solvent (w/v) ratio on oil yield were investigated. The oilseeds contained high fibre, fat and protein. Oilseeds-to-solvent (w/v) ratio (1:8) provided the highest oil yield. Overall, acetone was suggested as a suitable hexane replacer due to its higher oil recovery, similar fatty acid profile and oil physicochemical properties with higher antioxidant activity. Ethanol-extracted oil contained higher amounts of omega-9 MUFA, which may indicate the influence of extraction solvent on final fatty acid composition and thus final oil application

Solution enhanced dispersion by supercritical fluids (SEDS): an approach in particle engineering to modify aqueous solubility of andrographolide from Andrographis paniculata extract

The objective of study is to improve aqueous solubility of andrographolide through particle engineering using Solution Enhanced Dispersion by Supercritical Fluids (SEDS) approach. The precipitation pattern of sticky crude Andrographis paniculata extract from CO2-acetone system and CO2-acetone:ethanol (v/v) 1:1 system as well as the aqueous solubility of andrographolide precipitated were first studied at different pressure (100, 150 bar) and temperature (40, 50 °C) combination (full factorial design). The modification of aqueous solubility of andrographolide was then attempted by manipulating its precipitation process from CO2-solvent systems consisting of single solvent and solvent mixture at different proportions (v/v) at the appropriate pressure-temperature combination. A. paniculata powder precipitated from CO2-acetone system at 150 bar, 40 °C was found to be large, irregularly shaped, less crystalline with the highest andrographolide aqueous solubility (twofold increment compared to crude extract) and recovery compared to those precipitated from CO2-ethanol system and other CO2-solvent mixture systems. Complete dissolution of andrographolide from A. paniculata powder precipitated from CO2-acetone system had been achieved within 90 min. For SEDS precipitation under solvent mixture system, with increment of proportion of ethanol from 25% to 75%, larger particles and change of powder morphology from stripes into plates were resulted. Based on the higher aqueous solubility and dissolution of andrographolide, recovery as well as a different morphology observed from the less crystalline A. paniculata powder precipitated from CO2-acetone system, less impurities could have co-precipitated with andrographolide

Role of polymers as crystal growth inhibitors in coprecipitation via solutionenhanced dispersion by supercritical fluids (SEDS) to improve andrographolide dissolution from standardized Andrographis paniculata extract

The poor aqueous solubility and dissolution rate of andrographolide in aqueous gastrointestinal fluids often cause low oral bioavailability. In this work, Andrographis paniculata extract containing 16% andrographolide was coprecipitated with Pluronic F127, Eudragit EPO, and Eudragit L100-55 via solution-enhanced dispersion by supercritical fluids (SEDS) to improve andrographolide dissolution in simulated intestinal fluid (pH 7.4). The SEDS working parameters were set constant as follows: 150 bar, 40 °C, CO2 flow rate 15 L/min (1 bar, 25 °C), liquid feed flow rate 0.5 mL/min, and 25 mg/mL of A. paniculata extract. SEDS coprecipitates formulated with lower Eudragit L100-55:A. paniculata mass ratios exhibited improved andrographolide dissolution in SIF (pH 7.4), while SEDS coprecipitates formulated with either Pluronic F127:A. paniculata or Eudragit EPO:A. paniculata at any mass ratio exhibited poorer andrographolide dissolution (<0.03 mg/mL released in 90 min) than SEDS-precipitated A. paniculata extract powder (0.06 mg/mL released in 90 min). In particular, SEDS coprecipitates formulated with a Eudragit L100-55:A. paniculata mass ratio of 6:25 were found to have the highest andrographolide release and dissolution rate in SIF (pH 7.4) (0.09 mg/mL released in 30 min). SEDS coprecipitation was successful, as indicated by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and Fourier-transform infrared (FTIR) analysis

The Sweet Surrender: How Myeloid Cell Metabolic Plasticity Shapes the Tumor Microenvironment

Immune cells are one of the most versatile cell types, as they can tailor their metabolic activity according to their required function. In response to diverse environmental cues, immune cells undergo metabolic reprogramming to support their differentiation, proliferation and pro-inflammatory effector functions. To meet a dramatic surge in energetic demand, immune cells rewire their metabolism to utilize aerobic glycolysis. This preferential use of glycolysis even under aerobic conditions is well established in tumor cells, and is known as the “Warburg effect.” Tumor cells avidly use glucose for aerobic glycolysis, thereby creating a nutrient-starved microenvironment, outcompeting T cells for glucose, and directly inhibiting T-cell anti-tumoral effector function. Given that both immune and tumor cells use similar modes of metabolism in the tumor stroma, it is imperative to identify a therapeutic window in which immune-cell and tumor-cell glycolysis can be specifically targeted. In this review, we focus on the Warburg metabolism as well as other metabolic pathways of myeloid cells, which comprise a notable niche in the tumor environment and promote the growth and metastasis of malignant tumors. We examine how differential immune-cell activation triggers metabolic fate, and detail how this forbidding microenvironment succeeds in shutting down the vigorous anti-tumoral response. Finally, we highlight emerging therapeutic concepts that aim to target immune-cell metabolism. Improving our understanding of immunometabolism and immune-cell commitment to specific metabolic fates will help identify alternative therapeutic approaches to battle this intractable disease

Co-infection with Chikungunya virus alters trafficking of pathogenic CD8(+) T cells into the brain and prevents Plasmodium-induced neuropathology

Arboviral diseases have risen significantly over the last 40 years, increasing the risk of co‐infection with other endemic disease such as malaria. However, nothing is known about the impact arboviruses have on the host response toward heterologous pathogens during co‐infection. Here, we investigate the effects of Chikungunya virus (CHIKV ) co‐infection on the susceptibility and severity of malaria infection. Using the Plasmodium berghei ANKA (PbA) experimental cerebral malaria (ECM ) model, we show that concurrent co‐infection induced the most prominent changes in ECM manifestation. Concurrent co‐infection protected mice from ECM mortality without affecting parasite development in the blood. This protection was mediated by the alteration of parasite‐specific CD8+ T‐cell trafficking through an IFN γ‐mediated mechanism. Co‐infection with CHIKV induced higher splenic IFN γ levels that lead to high local levels of CXCL 9 and CXCL 10. This induced retention of CXCR 3‐expressing pathogenic CD8+ T cells in the spleen and prevented their migration to the brain. This then averts all downstream pathogenic events such as parasite sequestration in the brain and disruption of blood–brain barrier that prevents ECM ‐induced mortality in co‐infected mice

CD8+ T Cells and IFN-γ Mediate the Time-Dependent Accumulation of Infected Red Blood Cells in Deep Organs during Experimental Cerebral Malaria

Background: Infection with Plasmodium berghei ANKA (PbA) in susceptible mice induces a syndrome called experimental cerebral malaria (ECM) with severe pathologies occurring in various mouse organs. Immune mediators such as T cells or cytokines have been implicated in the pathogenesis of ECM. Red blood cells infected with PbA parasites have been shown to accumulate in the brain and other tissues during infection. This accumulation is thought to be involved in PbA–induced pathologies, which mechanisms are poorly understood. Methods and Findings: Using transgenic PbA parasites expressing the luciferase protein, we have assessed by real-time in vivo imaging the dynamic and temporal contribution of different immune factors in infected red blood cell (IRBC) accumulation and distribution in different organs during PbA infection. Using deficient mice or depleting antibodies, we observed that CD8 + T cells and IFN-c drive the rapid increase in total parasite biomass and accumulation of IRBC in the brain and in different organs 6–12 days post-infection, at a time when mice develop ECM. Other cells types like CD4 + T cells, monocytes or neutrophils or cytokines such as IL-12 and TNF-a did not influence the early increase of total parasite biomass and IRBC accumulation in different organs. Conclusions: CD8 + T cells and IFN-c are the major immune mediators controlling the time-dependent accumulation of P. berghei-infected red blood cells in tissues

Involvement of chemokine receptors and adhesion molecules in the regulation of Experimental Cerebral Malaria.

Leukocytes in particular CD8+ T cells migration to the brain and parasite sequestration are involved in experimental cerebral malaria (ECM). We hypothesized that ECM is initiated by parasite sequestration in the brain, by adhering to endothelium and/or monocytes or macrophages. Firstly, we assessed the role of two chemokine receptors CCR2 and CCR5, in leukocyte trafficking to the brain and other organs in ECM and sequestration of infected red blood cells (iRBC). We infected CCR2-deficient mice (50% monocyte reduction) with PbAluc and treated with anti-M-CSF receptor mAb. CCR2-/- treated mice died of ECM with the same parasitemia and parasite biomass as non-treated mice. Next, we investigated the role of CCR5 in ECM. CCR5-deficient mice were as susceptible to ECM as WT mice with no difference in parasitemia and parasite accumulation. Lastly, we investigated the involvement of adhesion molecules (ICAM-1) in iRBC sequestration. Rag2-deficient and C57BL/6J mice treated with anti-ICAM-1 mAb showed an increase in parasitemia with no difference in bioluminescence imaging compared to non-treated mice. These results suggest that iRBC do not adhere to monocytes and/or macrophages; CCR5 is not involved in T cells recruitment; and ICAM-1 might not be the major determinant adhesion molecule during effector phase.Bachelor of Science in Biomedical Science

Interferons and Interferon Regulatory Factors in Malaria

10.1155/2014/243713Mediators of inflammation20141-2