Background: Recent analyses have described metabolomic markers for depression and suicidal ideation in non-pregnant adults. We examined the metabolomic profile of antepartum depression and suicidal ideation during mid-pregnancy, a time of high susceptibility to mood disorders. Methods: We collected fasting blood from 100 pregnant Peruvian women and profiled 307 plasma metabolites using liquid chromatography-mass spectrometry. We used the Patient Health Questionnaire 9 to define antepartum depression (score ≥ 10) and suicidal ideation (having thoughts that you would be better off dead, or of hurting yourself). Logistic regression was used to calculate odds ratios (ORs). Results: Three triacylglycerol metabolites (C48:5 triacylglycerol [OR = =1.89; 95% confidence interval (CI): 1.14–3.14], C50:6 triacylglycerol [OR = =1.88; 95%CI: 1.13–3.14], C46:4 triacylglycerol [OR = =1.89; 95%CI: 1.11–3.21]) were associated with higher odds of antepartum depression and 4 metabolites (betaine [OR = =0.56; 95%CI:0.33–0.95], citrulline [OR = =0.58; 95%CI: 0.34–0.98], C5 carnitine [OR = =0.59; 95%CI: 0.36–0.99], C5:1 carnitine [OR = =0.59; 95%CI: 0.35–1.00]) with lower odds of antepartum depression. Twenty-six metabolites, including 5-hydroxytryptophan (OR = =0.52; 95%CI: 0.30–0.92), phenylalanine (OR = =0.41; 95%CI: 0.19–0.91), and betaine (OR = =0.53; 95%CI: 0.28–0.99) were associated with lower odds of suicidal ideation. Limitations: Our cross-sectional study could not determine whether metabolites prospectively predict outcomes. No metabolites remained significant after multiple testing correction; these novel findings should be replicated in a larger sample. Conclusions: Antepartum suicidal ideation metabolomic markers are similar to markers of depression among non-pregnant adults, and distinct from markers of antepartum depression. Findings suggest that mood disorder in pregnancy shares metabolomic similarities to mood disorder at other times and may further understanding of these conditions’ pathophysiology. / Revisión por pares

Coral reefs are in global decline due to ocean warming and ocean acidification. While these stressors are commonly studied in climate change predictions, salinity, although being an important environmental factor, is not well understood. The response of the coral holobiont (the association of the coral host, its algal endosymbiont and a suit of other microbes) to changes in salinity and the contribution of each holobiont compartment underlying the necessary osmoadaptation remain especially elusive. Interestingly, we find some of the most thermotolerant corals in some of the most saline seas, e.g. the Red Sea and the Persian Arabian Gulf. This observation sparked the hypothesis of a link between osmoadaptation and coral thermotolerance. Here, we set out to elucidate the putative effects of high salinity on conveying thermotolerance and thereby a possible link to bleaching in the context of the coral holobiont. For this, we conducted a series of heat stress experiments at different salinities in the coral model Aiptasia and subsequently validated our findings in corals from the central Red Sea. We confirm a role of osmoadaptation in increased thermotolerance and reduced bleaching in Aiptasia and Red Sea corals. This salinity-conveyed thermotolerance was characterized by a reduction in algal endosymbiont loss, photosystem damage and leakage of damaging reactive oxygen species (ROS) in high salinity. Further analysis of the osmoadaptation response using targeted GC-MS uncovered high levels of the sugar floridoside at high salinity only in holobionts that show the salinity-conveyed thermotolerance. The increase of floridoside, an osmolyte capable of scavenging ROS, and the concurrent reduction of ROS argues for a mechanistic link of increased thermotolerance and reduced bleaching in high salinities. In addition, the restructuring of the microbiome at high salinity that aligned with the difference in thermotolerance in Aiptasia may be indicative of a microbial contribution towards a more beneficial holobiont composition. Hence, emphasizing the potential cumulative contribution of each holobiont compartment during stress-resilience, as well as highlighting the overall role of osmoadaptation in the thermotolerance of corals.

No description available.

Cannabis sativa has a complex history of classification and traditional use. Cannabis sativa ssp. sativa and spp. indica are the two major lineages of cannabis and, through artificial selection, many strains or cultivars are found within each group are bred together to yield hybrid plants. New methods of classification based on Δ⁹-Tetrahydrocannbinol (THC) and Cannabidiol (CBD) content as well as minor cannabinoids and terpenes have emerged as a more effective classification of cannabis. However, the fidelity of cannabis varieties relative to their respective strain names and lineages (indica, sativa and hybrid) based on chemistry has been brought into question. THC and more recently CBD are collectively responsible for the psychoactive and therapeutic effects of cannabis and minor cannabinoids and terpenes are emerging as having their own unique bioactivity or synergistic effects in vitro. Considering the variation in cannabis chemical profile and infidelity to strain names or lineages, we investigated the cannabinoid, terpene and metabolomic profiles of 33 THC-dominant strains (113 samples) to evaluate existing and alternative chemistry-based classification systems using multivariate analyses. Here, we conclude that Indica-Sativa-Hybrid designations are insufficient in describing variation in cannabinoid, terpene and metabolomic data, and that a terpene-based profile classification revealed robust groupings in cannabinoid-terpene data. However, terpene profiles were not discernable in metabolomic data. To investigate how chemical complexity and variability impacts bioactivity, we compared the activity of cannabis extracts to that of pure THC (and CBD) to determine if THC alone is driving activity. THC, CBD, and plant extracts were tested in vitro for cytotoxicity in BEAS-2Bs cells and for cannabinoid receptor signalling activity using a human CB₁-HEK293 cell model. THC did not completely dictate 24-hour toxicity in BEAS-2B cells suggesting that other extract components (beyond THC and CBD) are contributing to cytotoxicity. While CBD alone was 2x more toxic than THC alone, THC:CBD do no predict toxic concentration. THC within extracts appeared to drive efficacy at CB₁ receptors by reducing intracellular cAMP accumulation but did not dictate variation in EC₅₀. THC in extract also appeared to increase percent cAMP reduction in cells regardless of low CBD content but a 1:1 balanced THC/CBD extract revealed reduced percent cAMP reduction. Pure compounds compared to extracts of the same THC/CBD ratio performed very similarly at CB1 receptors besides 1:1 extract preparation having reduced % reduction of cAMP compared to 1:1 pure compounds suggestive of NAM by extract components. Regression modelling of THC within extract revealed a significant positive relationship in % cAMP reduction (Emax) but no significance in TC₅₀ and EC₅₀. This work demonstrates the importance of rigorous analysis of cannabis chemistry as well as evaluation of extracts in bioactivity assays.

Helminths are parasitic worms that can establish long-lived infections by modulating host immune responses. Helminth infection has been associated with a reduced prevalence of allergic disease in human populations, and impaired immunity to co-infecting pathogens. Several human and mouse studies suggest that helminths may impair host responses to concurrent bacterial infection. In this thesis, we study the extent to which helminth infection affects Salmonella colonization and how anthelmintic treatment (deworming) impacts immunity to Salmonella in a mouse model of co-infection. We find that helminth co-infection allows Salmonella to establish in the lumen of the small intestine. Further, we find that deworming prior to bacterial infection restores impaired immunity to Salmonella in the small intestine, however, deworming after Salmonella has established during helminth co-infection does not revert elevated bacterial burdens. To ensure their longevity in the host, helminths release immunomodulatory molecules, and modulate immunity through changes in the gut microbiota. The microbiota is known to influence mucosal immunity through the production of metabolites, but metabolites have not received much attention in the context of helminth modification of immune responses. This thesis uncovers the impact of helminth infection on levels of short-chain fatty acids (SCFAs) and bile acids, two groups of metabolites with immunomodulatory potential. We found that helminth infection increases small intestinal levels of the branched-chain SCFA isovalerate and lowers the small intestinal bile acid concentration. We next explored the consequences of these metabolite shifts on susceptibility to bacterial infection, helminth fitness and regulatory T cells. Collectively, these results contribute to the understanding of host-pathogen interactions in a co-infection scenario, which ultimately, will help to inform strategies for disease control in helminth-endemic areas. Further, our data contributes to the characterization of the helminth-modified intestinal metabolome, which future work can build on to reveal novel immunomodulatory pathways that can be targeted to relieve symptoms in inflammatory diseases such as allergic asthma. / Graduate / 2022-12-06

Widespread sedentary lifestyle and unhealthy eating habits in the last few decades have resulted in a dramatic increase of the number of people affected by obesity, type 2 diabetes, and cardiovascular diseases. The study of these pathological conditions revealed that impaired metabolism often causes these disorders. Lipid metabolism research has contributed significantly to determining mechanisms underlying metabolic disorders. Omega-3 fatty acids are an interesting target for lipidomics studies because they were shown to lower risk of cardiovascular diseases and are hypothesized to regulate lipid metabolism. In this work, I optimized lipid extraction and chemical modification methods for analysis of fatty acids profile of tissue samples and biofluids using comprehensive two-dimensional gas chromatography coupled to mass spectrometry (GCxGC-MS). At first, I evaluated the relative amount of omega-3 fatty acids in red blood cells (Omega-3 index) of people living in Czech Republic in either the capital city (n=476) or the rural region (n=388). For this large-scale project, I extracted phospholipids from red blood cell (RBC) membranes, transesterified them into fatty acid methyl esters (FAMEs), and measured their profile by GCxGC-MS. The mean Omega-3 index was 3.56 mol % and I detected no significant...

Acute myeloid leukemia (AML) is characterized by a blockage in the differentiation of myeloid cells at different stages. CD44-ligation using anti-CD44 monoclonal antibodies (mAbs) has been shown to reverse the blockage of differentiation and to inhibit the proliferation of blasts in most AML-subtypes. However, the molecular mechanisms underlying this property have not been fully elucidated. Here, we sought to I) analyze the effects of anti-CD44 mAbs on downstream signaling pathways, including the ERK1/2 (extracellular signal-regulated kinase 1 and 2) and mTOR (mammalian target of rapamycin) pathways and II) use state-of-the-art Nuclear Magnetic Resonance (NMR) technology to determine the global metabolic changes during differentiation induction of AML cells using anti-CD44 mAbs and other two previously reported differentiation agents. In the first objective (Chapter 4), our studies provide evidence that CD44-ligation with specific mAbs in AML cells induced an increase in ERK1/2 phosphorylation. The use of the MEK inhibitor (U0126) significantly inhibited the CD44-induced differentiation of HL60 cells, suggesting that ERK1/2 is critical for the CD44-triggered differentiation in AML. In addition, this was accompanied by a marked decrease in the phosphorylation of the mTORC1 and mTORC2 complexes, which are strongly correlated with the inhibition of the PI3K/Akt pathway. In the second objective (Chapter 5), 1H NMR experiments demonstrated that considerable changes in the metabolic profiles of HL60 cells were induced in response to each differentiation agent. These most notable metabolites that significantly changed upon CD44 ligation were involved in the tricarboxylic acid (TCA) cycle and glycolysis such as, succinate, fumarate and lactate. Therefore, we sought to analyze the mechanisms underlying their alterations. Our results revealed that anti-CD44 mAbs treatment induced upregulation in fumarate hydratase (FH) expression and its activity which was accompanied by a decrease in succinate dehydrogenase (SDH) activity. Interestingly, our results indicated that FH induced by anti-CD44 mAb is regulated through the activation of the ERK1/2 pathway. Therefore, our findings highlight new elements in support for the use of anti-CD44 mAbs in AML therapies and open new perspectives to use metabolic profiling as a tool to support the potential possibilities for the development of CD44-targeted therapy of AML.

No description available.

No description available.

<p> Biological thiols are a class of labile and redox-active metabolite with significant interest to biomedical research due to their involvement in redox mechanisms of cell signaling and physiological control. As a result of oxidative stress, levels of various reduced thiols and oxidized disulfides are altered, which disrupts major cellular regulation pathways modulating protein function and gene expression. Thus, analysis of thiols in biological fluids is essential for understanding the role of oxidative stress and thiol dysregulation in aging and human diseases. However, reliable ex-vivo thiol determination is challenging due to their low abundance and susceptibility to auto-oxidation and thiol-disulfide exchange reactions. In this thesis, capillary electrophoresis-electrospray ionization-mass spectrometry (CE-ESI-MS) in conjunction with maleimide labeling is developed as an integrative strategy for comprehensive plasma thiol redox status analysis for metabolomics. Maleimide labeling helps to address both major constraints in thiol analysis by stabilizing free sulfhydryl groups as their thioether adducts while improving ionization efficiency and analytical sensitivity. This enhancement in ionization efficiency can be quantitatively predicted based on relative changes in fundamental physicochemical properties of thiols that occur upon covalent derivatization when using multivariate calibration. On-line sample preconcentration together with thiol-selective labeling using a cationic quaternary ammonium maleimide analog allowed for simultaneous analysis of reduced thiols and intact oxidized disulfides by CE-ESI-MS with low nanomolar detection limits of 8-30 nM. Improved identification of unknown low abundance thiols and other classes of polar metabolites is also demonstrated by prediction of relative migration times in CE that is complementary to ESI-MS. Comprehensive plasma thiol speciation together with untargeted profiling of polar metabolites provides a novel platform for holistic understanding of complex changes in metabolic networks associated with thiol dysregulation and/or nutritional intervention for the prevention or treatment of human disorders. </p> / Thesis / Master of Science (MSc)