Multivariable analysis of host amino acids in plasma and liver during infection of malaria parasite Plasmodium yoelii

Possible microRNA-based mechanism underlying relationship between chronic spontaneous urticaria and Blastocystis

BACKGROUND

Blastocystis spp. has been proposed as a possible cause of extraintestinal clinical signs such as urticaria pathogenesis.

OBJECTIVES

The aim of this study was to investigate the differences between microRNA (miRNA) expression profiles of Chronic spontaneous urticaria (CSU) patients in the presence or absence of Blastocystis spp. as well as healthy controls. Additionally, cellular pathways which are affected in the presence of Blastocystis spp. were identified.

METHODS

Twenty patients diagnosed with CSU were enrolled in the study and divided into equally two groups according to the presence of Blastocystis spp. Besides, six healthy individuals were included in the study. The expression profiles of 372 human-derived miRNAs have been investigated in serum samples from CSU patients and healthy controls with miScript miRNA PCR Array Human miRBase Profiler.

RESULTS

Compared to Blastocystis-negative (BN)-CSU patients, expression of 3 miRNAs (hsa-miR-3183, hsa-miR-4469, hsa-miR-5191) were found to be downregulated by at least two-fold (p < 0.05) in Blastocystis-positive (BP)-CSU patients. Additionally, the miRNA expression profiles of six healthy individuals (n = 3 Blastocystis-positive, n = 3 Blastocystis-negative) were analyzed and it was determined that the expressions of 7 miRNAs (hsa-miR-4661-5p, hsa-miR-4666a-5p, hsa-miR-4803, hsa-miR-5587-5p, hsa-miR-4500, hsa-miR-5680, hsa-miR-382-3p) increased at least 3-fold in the serum of individuals with Blastocystis-positive compared to Blastocystis-negative subjects. Most down-regulated miRNAs, in BP-CSU patients, affect cell adhesion molecules (CAMs), and signaling pathways therefore, Blastocystis spp. presence may influence the clinical presentation of urticaria by leading to unbalanced immunity. In addition, Blastocystis spp. presence may be influenced TGF- β signaling pathway through altered miRNAs and may be laying the groundwork for the development of CSU in healthy individuals.

CONCLUSIONS

As a consequence, this is the first report to show that the miRNA expression profile is affected by the presence of Blastocystis spp. Further miRNA-based studies are needed in order to enlighten the exact underlying molecular mechanisms of the relationship between Blastocystis spp. and CSU.

Comparative Analysis of Host Metabolic Alterations in Murine Malaria Models with Uncomplicated or Severe Malaria

Malaria varies in severity, with complications ranging from uncomplicated to severe malaria. Severe malaria could be attributed to peripheral hyperparasitemia or cerebral malaria. The metabolic interactions between the host and Plasmodium species are yet to be understood during these infections of varied pathology and severity. An untargeted metabolomics approach utilizing the liquid chromatography-mass spectrometry platform has been used to identify the affected host metabolic pathways and associated metabolites in the serum of murine malaria models with uncomplicated malaria, hyperparasitemia, and experimental cerebral malaria. We report that mice with malaria share similar metabolic attributes like higher levels of bile acids, bile pigments, and steroid hormones that have been reported for human malaria infections. Moreover, in severe malaria, upregulated levels of metabolites like phenylalanine, histidine, valine, pipecolate, ornithine, and pantothenate, with decreased levels of arginine and hippurate, were observed. Metabolites of sphingolipid metabolism were upregulated in experimental cerebral malaria. Higher levels of 20-hydroxy-leukotriene B₄ and epoxyoctadecamonoenoic acids were found in uncomplicated malaria, with lower levels observed for experimental cerebral malaria. Our study provides insights into host biology during different pathological stages of malaria disease and would be useful for the selection of animal models for evaluating diagnostic and therapeutic interventions against malaria. The raw data files are available via MetaboLights with the identifier MTBLS4387.

Plasma amino acid levels in individuals with bacterial pneumonia and healthy controls

BACKGROUND & AIMS

Amino acids play an important role in immune responses and as neurotransmitters. During the course of a bacterial pneumonia episode, from the onset to the recovery phase, immune responses dramatically change, as does the metabolism of amino acids, a concept referred to as immuno-nutrition. We investigated the differences in plasma amino acid levels (PAA) between the acute and recovery phases in individuals with community-acquired pneumonia (CAP) and healthy controls.

METHODS

Two groups of participants were recruited: Healthy adults aged over 60 years and patients hospitalized with CAP. Samples were collected on Day 0 (the day of admission) and Day 7 (after 6-8 days treatment).

RESULTS

A total of 93 healthy adults and 60 patients with CAP participated in the study. Of those with CAP, 43 had their amino acids measured on Day 7. Patients with CAP had markedly decreased PAA of 12 amino acids on Day 0. Citrulline, histidine, and tryptophan remained low in male, while aspartic acid, asparagine, ornithine, proline, and threonine were higher on Day 7 in both males and females. Phenylalanine increased at Day 0 and Day7.

CONCLUSIONS

The findings suggest that the host response against bacterial infection changed the plasma amino acid levels. PAA on Day 7 (representing convalescence) continued to display an amino acid profile distinct from that observed in healthy individuals. Based on these findings, reconsideration for providing amino acids to patients with bacterial pneumonia should be needed depending on stage of the pneumonia from the perspective of immuno-nutrition.

Tissue/Biofluid Specific Molecular Cartography of Leishmania donovani Infected BALB/c Mice: Deciphering Systemic Reprogramming

Pathophysiology of visceral leishmaniasis (VL) is not fully understood and it has been widely accepted that the parasitic components and host immune response both contribute to the perpetuation of the disease. Host alterations during leishmaniasis is a feebly touched area that needs to be explored more to better understand the VL prognosis and diagnosis, which are vital to reduce mortality and post-infection sequelae. To address this, we performed untargeted metabolomics of Leishmania donovani (Ld) infected, uninfected and treated BALB/c mice’s tissues and biofluids to elucidate the host metabolome changes using gas chromatography–mass spectrometry. Univariate and multivariate data treatments provided numerous significant differential hits in several tissues like the brain, liver, spleen and bone marrow. Differential modulations were also observed in serum, urine and fecal samples of Ld-infected mice, which could be further targeted for biomarker and diagnostic validations. Several metabolic pathways were found to be upregulated/downregulated in infected (TCA, glycolysis, fatty acids, purine and pyrimidine, etcetera) and treated (arginine, fumaric acid, orotic acid, choline succinate, etcetera) samples. Results also illustrated several metabolites with different pattern of modulations in control, infected and treated samples as well as in different tissues/biofluids; for e.g. glutamic acid identified in the serum samples of infected mice. Identified metabolites include a range of amino acids, saccharides, energy-related molecules, etcetera. Furthermore, potential biomarkers have been identified in various tissues—arginine and fumaric acid in brain, choline in liver, 9-(10) EpOME in spleen and bone marrow, N-acetyl putrescine in bone marrow, etcetera. Among biofluids, glutamic acid in serum, hydrazine and deoxyribose in urine and 3-Methyl-2-oxo pentanoic acid in feces are some of the potential biomarkers identified. These metabolites could be further looked into for their role in disease complexity or as a prognostic marker. The presented profiling approach allowed us to attain a metabolic portrait of the individual tissue/biofluid modulations during VL in the host and represent a valuable system readout for further studies. Our outcomes provide an improved understanding of perturbations of the host metabolome interface during VL, including identification of many possible potential diagnostic and therapeutic targets.

Investigation of Proteus vulgaris and Elizabethkingia meningoseptica invasion on muscle oxidative stress and autophagy in Chinese soft-shelled turtle (Pelodiscus sinensis)

Muscle is an important structural tissue in aquatic animals and it is susceptible to bacterial and fungal infection, which could affect flesh quality and health. In this study, Chinese soft-shelled turtles were artificially infected with two pathogens, Proteus vulgaris and Elizabethkingia meningoseptica and the effects on muscle nutritional characteristics, oxidative stress and autophagy were assayed. Upon infection, the muscle nutritional composition and muscle fiber structure were notably influenced. Meanwhile, the mRNA expression of Nrf2 was down-regulated and Keap1 up-regulated, thus resulting in a decrease in antioxidant capacity and oxidative stress. However, with N-acetylcysteine treatment, the level of oxidative stress was decreased, accompanied by significant increases in antioxidant enzyme activities and the mRNA levels of SOD, CAT, GSTCD, and GSTO1. Interestingly, there was a significant increase in autophagy in the muscle tissue after the pathogen infection, but this increase could be reduced by N-acetylcysteine treatment. Our findings suggest that muscle nutritional characteristics were dramatically changed after pathogen infection, and oxidative stress and autophagy were induced by pathogen infection. However, N-acetylcysteine treatment could compromise the process perhaps by decreasing the ROS level and regulating Nrf2-antioxidant signaling pathways.

Vibrio parahaemolyticus infection impaired intestinal barrier function and nutrient absorption in Litopenaeus vannamei

The intestine is the primary target of pathogenic microbes during invasion. However, the interaction of Vibrio parahaemolyticus (V. parahaemolyticus) with intestinal epithelial cells and its effects on the intestinal function of Litopenaeus vannamei (L. vannamei) are poorly studied. Therefore, the aim of this study was to investigate the influence of V. parahaemolyticus infection on intestinal barrier function and nutrient absorption in L. vannamei. In the present study, a total of 90 shrimp were randomly divided into two groups including the control group and V. parahaemolyticus infection group (final concentration of 1 × 10⁵ CFU/mL), with three replicates per group. The result showed that compared with the control group, V. parahaemolyticus infection increased (P < 0.05) serum diamine oxidase activity and endotoxin quantification, and down-regulated (P < 0.05) the mRNA levels of intestinal peroxinectin, integrin, midline fasciclin at 48 h and 72 h; V. parahaemolyticus infection decreased (P < 0.05) the mRNA expression of intestinal amino acid transporter (CAT1, EAAT3 and ASCT1) and glucose transporter (SGLT-1, GLUT) at 24 h, 48 h and 72 h, and increased (P < 0.05) serum glucose and amino acid (Asp, Thr, Ser, Glu, Gly, Ala, Val, Ile, Leu, Tyr, Phe, Lys, His and Arg) concentration at 24 h. The results indicated that V. parahaemolyticus infection increased intestinal permeability, inhibited absorption of glucose and amino acid in L. vannamei.

Rapid Discrimination of Malaria- and Dengue-Infected Patients Sera Using Raman Spectroscopy

Malaria and dengue have overlapping clinical symptoms and are prevalent in the same geographic region (tropical and subtropical), hence precise diagnosis is challenging. The high mortality rate associated with both malaria and dengue could be attributed to "false", "delayed", or "missed" diagnosis. The present study thus aims to stratify malaria and dengue using Raman spectroscopy (RS). In total, 130 human sera were analyzed for model development and double-blinded testing. Principal components linear discriminant analysis (PC-LDA) of acquired RS-spectra could classify malaria and dengue with a minor overlap of 16.7%. Receiver operating characteristic (ROC) analysis of test samples showed sensitivity/specificity of 0.9529 for malaria vs healthy controls (HC) and 0.9584 for dengue vs HC. The Raman findings were complemented by mass spectroscopy (MS)-based metabolite analysis of 8 individuals, each from malaria, dengue, and HC. Several of the metabolites, including amino acids, cell-free DNA, creatinine, and bilirubin, assigned for the predominant RS-bands were also identified by MS and showed similar trends. Our data clearly indicates that RS-based serum analysis using a microprobe has immense potential for early, accurate, and automated detection and discrimination of malaria and dengue, and in the future, it could be extrapolated in field-settings combined with hand-held RS. Further, this approach might be extended to diagnose other closely related infections with similar clinical manifestations.

Amino Acids As Mediators of Metabolic Cross Talk between Host and Pathogen

The interaction between host and pathogen decidedly shapes the outcome of an infection, thus understanding this interaction is critical to the treatment of a pathogen-induced infection. Although research in this area of cell biology has yielded surprising findings regarding interactions between host and pathogen, understanding of the metabolic cross talk between host and pathogen is limited. At the site of infection, host and pathogen share similar or identical nutritional substrates and generate common metabolic products, thus metabolic cross talk between host and pathogen could profoundly affect the pathogenesis of an infection. In this review, we present results of a recent discovery of a metabolic interaction between host and pathogen from an amino acid (AA) metabolism-centric point of view. The host depends on AA metabolism to support defensive responses against pathogens, while the pathogens modulate AA metabolism for its own advantage. Some AA, such as arginine, asparagine, and tryptophan, are central points of competition between the host and pathogen. Thus, a better understanding of AA-mediated metabolic cross talk between host and pathogen will provide insight into fruitful therapeutic approaches to manipulate and prevent progression of an infection.

Efficacy and safety of artemisinin combination therapy (ACT) for non-falciparum malaria: a systematic review

Background

Artemisinin combination therapy (ACT) is recommended as first-line treatment for uncomplicated Plasmodium falciparum malaria, whereas chloroquine is still commonly used for the treatment of non-falciparum species (Plasmodium vivax, Plasmodium ovale and Plasmodium malariae). A more simplified, more uniform treatment approach across all malaria species is worthwhile to be considered both in endemic areas and for malaria as an imported condition alike.

Methods

A PROSPERO-registered systematic review to determine the efficacy and safety of ACT for the treatment of non-falciparum malaria was conducted, following PRISMA guidelines. Without language restrictions, Medline/PubMed, Embase, Cochrane Central Register of Controlled Trials, Web of Science, LILACS, Biosis Previews and the African Index Medicus were searched for studies published up to November 2014.

Results

The literature search identified 986 reports; 40 publications were found eligible for inclusion, all of them on non-falciparum malaria in endemic areas. Most evidence was available for P. vivax (n = 35). Five clinical trials in total were identified evaluating ACT for P. ovale, P. malariae and Plasmodium knowlesi. Most ACT presentations have high efficacy against P. vivax parasites; artemisinin-based combinations have shorter parasite and fever clearance times compared to chloroquine. ACT is as effective as chloroquine in preventing recurrent parasitaemia before day 28. Artemisinin-based combinations with long half-lives show significantly fewer recurrent parasitaemia up to day 63. The limited evidence available supports both the use of chloroquine and an ACT for P. ovale and P. malariae. ACT seems to be preferable for optimal treatment of P. knowlesi.

Conclusion

ACT is at least equivalent to chloroquine in effectively treating non-falciparum malaria. These findings may facilitate development of simplified protocols for treating all forms of malaria with ACT, including returning travellers. Obtaining comprehensive efficacy and safety data on ACT use for non-falciparum species particularly for P. ovale, P. malariae and P. knowlesi should be a research priority.

Trial registration

CRD42014009103

Electronic supplementary material

The online version of this article (doi:10.1186/1475-2875-13-463) contains supplementary material, which is available to authorized users.