The Role of Amino Acids in Neurotransmission and Fluorescent Tools for Their Detection

Amino acid transporters in neurological disorders and neuroprotective effects of cysteine derivatives

For most diseases and disorders occurring in the brain, the full causes behind them are yet unknown, but many show signs of dysfunction of amino acid transporters or abnormalities in amino acid metabolism. The blood-brain barrier (BBB) plays a key role in supporting the function of the central nervous system (CNS). Because of its unique structure, the BBB can maintain the optimal environment for CNS by controlling the passage of hydrophilic molecules from blood to the brain. Nutrients, such as amino acids, can cross the BBB via specific transporters. Many amino acids are essential for CNS function, and dysfunction of these amino acid transporters can lead to abnormalities in amino acid levels. This has been linked to causes behind certain genetic brain diseases, such as schizophrenia, autism spectrum disorder, and Huntington's disease (HD). One example of crucial amino acids is L-Cys, the rate-limiting factor in the biosynthesis of an important antioxidant, glutathione (GSH). Deficiency of L-Cys and GSH has been linked to oxidative stress and has been shown as a plausible cause behind certain CNS diseases, like schizophrenia and HD. This review presents the current status of potential L-Cys therapies and gives future directions that can be taken to improve amino acid transportation related to distinct CNS diseases.

Kinetic and Spectroscopic Investigation of the Y157F and C93G/Y157F Variants of Cysteine Dioxygenase: Dissecting the Roles of the Second-Sphere Residues C93 and Y157

In mammals, l-cysteine (Cys) homeostasis is maintained by the mononuclear nonheme iron enzyme cysteine dioxygenase (CDO), which oxidizes Cys to cysteine sulfinic acid. CDO contains a rare post-translational modification, involving the formation of a thioether cross-link between a Cys residue at position 93 (Mus musculus CDO numbering) and a nearby tyrosine at position 157 (Cys-Tyr cross-link). As-isolated CDO contains both the cross-linked and non-cross-linked isoforms, and formation of the Cys-Tyr cross-link during repeated enzyme turnover increases CDO's catalytic efficiency by ∼10-fold. Interestingly, while the C93G CDO variant lacks the Cys-Tyr cross-link, it is similarly active as cross-linked wild-type (WT) CDO. Alternatively, the Y157F CDO variant, which also lacks the cross-link but maintains the free thiolate at position 93, exhibits a drastically reduced catalytic efficiency. These observations suggest that the untethered thiolate moiety of C93 is detrimental to CDO activity and/or that Y157 is essential for catalysis. To further assess the roles of residues C93 and Y157, we performed a spectroscopic and kinetic characterization of Y157F CDO and the newly designed C93G/Y157F CDO variant. Our results provide evidence that the non-cross-linked C93 thiolate stabilizes a water at the sixth coordination site of Cys-bound Y157F Fe(II)CDO. A water is also present, though more weakly coordinated, in Cys-bound C93G/Y157F Fe(II)CDO. The presence of a water molecule, which must be displaced by cosubstrate O2, likely makes a significant contribution to the ∼15-fold and ∼7-fold reduced catalytic efficiencies of the Y157F and C93G/Y157F CDO variants, respectively, relative to cross-linked WT CDO.

Unveiling the multifaceted antiproliferative efficacy of Cichorium endivia root extract by dual modulation of apoptotic and inflammatory genes, inducing cell cycle arrest, and targeting COX-2

Chicory (Cichorium endivia L. divaricatum) is a renowned medicinal plant traditionally used for various ailments, yet the pharmacological potential of its roots, particularly in terms of antitumor activity, remains elusive. In the present study, we explore, for the first time, the metabolomic profile of ethanolic extract from Cichorium endivia roots (CIR) and further unveil its antiproliferative potential. The untargeted phytochemical analysis UPLC/T-TOF-MS/MS identified 131 metabolites in the CIR extract, covering acids, amino acids, flavonoids, alkaloids, nucleotides, and carbohydrates. The antiproliferative activity of the CIR extract was tested in 14 cancer cell lines, revealing significant cytotoxicity (IC50: 2.85-29.15 μg mL-1) and a high selectivity index. Among the cells examined, the CIR extract recorded the most potent antiproliferative activity and selectivity toward HepG2 and Panc-1 cells, with an IC50 of 2.85 μg mL-1 and 3.86 μg mL-1, respectively, and SI > 10. Insights into the mode of action of the antiproliferative activity revealed that CIR extract induces cell arrest in the S phase while diminishing cell distribution in the G0/G1 and G2/M phases in HepG-2 and Panc-1 cells. Flow cytometric and RT-PCR analysis revealed that the CIR extract significantly triggers apoptosis and modulates the expression of pro-apoptotic and anti-apoptotic genes. Furthermore, the CIR extract exhibited a pronounced anti-inflammatory activity, as evidenced by down-regulating key cytokines in LPS-induced RAW 264.7 cells and selectively inhibiting the COX-2 enzyme. Finally, the CIR extract showed a robust total antioxidant capacity, together with potent free radicals and metal scavenging properties, highlighting its role in alleviating oxidative stress. Taken together, this study highlights the multifaceted therapeutic potential of CIR extract as a natural-based antitumor supplement.

Regulatory mechanisms of amino acids in ferroptosis

Ferroptosis, an iron-dependent non-apoptotic regulated cell death process, is associated with the pathogenesis of various diseases. Amino acids, which are indispensable substrates of vital activities, significantly regulate ferroptosis. Amino acid metabolism is involved in maintaining iron and lipid homeostasis and redox balance. The regulatory effects of amino acids on ferroptosis are complex. An amino acid may exert contrasting effects on ferroptosis depending on the context. This review systematically and comprehensively summarized the distinct roles of amino acids in regulating ferroptosis and highlighted the emerging opportunities to develop clinical therapeutic strategies targeting amino acid-mediated ferroptosis.

Toxin-derived peptides: An unconventional approach to alleviating cerebral stroke burden and neurobehavioral impairments

Cerebral stroke is a pressing global health concern, ranking as the second leading cause of mortality and resulting in persistent neurobehavioral impairments. Cerebral strokes, triggered by various embolic events, initiate complex signaling pathways involving neuroexcitotoxicity, ionic imbalances, inflammation, oxidative stress, acidosis, and mitochondrial dysfunction, leading to programmed cell death. Currently, the FDA has approved tissue plasminogen activator as a relatively benign intervention for cerebral stroke, leaving a significant treatment gap. However, a promising avenue has emerged from Earth's toxic creatures. Animal venoms harbor bioactive molecules, particularly neuropeptides, with potential in innovative healthcare applications. These venomous components, affecting ion channels, receptors, and transporters, encompass neurochemicals, amino acids, and peptides, making them prime candidates for treating cerebral ischemia and neurological disorders. This review explores the composition, applications, and significance of toxin-derived peptides as viable therapeutic agents. It also investigates diverse toxins from select venomous creatures, with the primary objective of shedding light on current stroke treatments and paving the way for pioneering therapeutic strategies capable of addressing neurobehavioral deficits.

Metabolomic-Based Comparison of Daphnia magna and Japanese Medaka Responses After Exposure to Acetaminophen, Diclofenac, and Ibuprofen

Pharmaceuticals are found in aquatic environments due to their widespread use and environmental persistence. To date, a range of impairments to aquatic organisms has been reported with exposure to pharmaceuticals; however, further comparisons of their impacts across different species on the molecular level are needed. In the present study, the crustacean Daphnia magna and the freshwater fish Japanese medaka, common model organisms in aquatic toxicity, were exposed for 48 h to the common analgesics acetaminophen (ACT), diclofenac (DCF), and ibuprofen (IBU) at sublethal concentrations. A targeted metabolomic-based approach, using liquid chromatography-tandem mass spectrometry to quantify polar metabolites from individual daphnids and fish was used. Multivariate analyses and metabolite changes identified differences in the metabolite profile for D. magna and medaka, with more metabolic perturbations for D. magna. Pathway analyses uncovered disruptions to pathways associated with protein synthesis and amino acid metabolism with D. magna exposure to all three analgesics. In contrast, medaka exposure resulted in disrupted pathways with DCF only and not ACT and IBU. Overall, the observed perturbations in the biochemistry of both organisms were different and consistent with assessments using other endpoints reporting that D. magna is more sensitive to pollutants than medaka in short-term studies. Our findings demonstrate that molecular-level responses to analgesic exposure can reflect observations of other endpoints, such as immobilization and mortality. Thus, environmental metabolomics can be a valuable tool for selecting sentinel species for the biomonitoring of freshwater ecosystems while also uncovering mechanistic information. Environ Toxicol Chem 2024;43:1339-1351. © 2024 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Differential protein expression and metabolite profiling in glaucoma: Insights from a multi-omics analysis

Various substances within the aqueous humor (AH) can directly or indirectly impact intraocular tissues associated with intraocular pressure (IOP), a critical factor in glaucoma development. This study aims to investigate individual changes in these AH substances and the interactions among altered components through a multi-omics approach. LC/MS analysis was conducted on AH samples from patients with exfoliation syndrome (XFS, n = 5), exfoliation glaucoma (XFG, n = 4), primary open-angle glaucoma (POAG, n = 11), and cataracts (control group, n = 7). Subsequently, differentially expressed proteins and metabolites among groups, alterations in their network interactions, and their biological functions were examined. Both data-independent acquisition and data-dependent acquisition methods were employed to analyze the AH proteome and metabolome, and the results were integrated for a comprehensive analysis. In the proteomics analysis, proteins upregulated in both the XFG and POAG groups were associated with lipid metabolism, complement activation, and extracellular matrix regulation. Metabolomic analysis highlighted significant changes in amino acids related to antioxidant processes in the glaucoma groups. Notably, VTN, APOA1, C6, and L-phenylalanine exhibited significant alterations in the glaucoma groups. Integration of individual omics analyses demonstrated that substances associated with inflammation and lipid metabolism, altered in the glaucoma groups, showed robust interactions within a complex network involving PLG, APOA1, and L-phenylalanine or C3, APOD, and L-valine. These findings offer valuable insights into the molecular mechanisms governing IOP regulation and may contribute to the development of new biomarkers for managing glaucoma.

Innovative Applications of Tenebrio molitor Larvae in the Production of Sustainable Meat Sausages: Quality and Safety Aspects

With the world's population continuing to grow, ensuring sustainable protein sources for everyone is becoming increasingly challenging. Despite meat being considered unsustainable, people find it challenging to abstain from consuming it. However, one solution to this dilemma could be the incorporation of mealworms into conventional meat products, i.e., sausages. The incorporation of mealworms into sausage formulations appears to shift the fatty acid profile towards higher levels of monounsaturated fats and polyunsaturated fatty acids (PUFAs), particularly omega-3s, potentially enhancing the nutritional value and offering health benefits. Therefore, our study aimed to improve the nutritional value and safety parameters of traditional sausages by enriching them with the flour of mealworm larvae. For this purpose, the larvae were reared on a sustainable substrate with brewery by-products, brewer's yeast, and carrots. They were used frozen and freeze-dried in sausage recipes, replacing pork in different proportions. The analysis of the product's chemical safety parameters (biogenic amines, nitrates and nitrites, volatile fatty acids (FA), and peroxide) and nutritional value (including collagen, cholesterol, amino acids, FA, and hydroxyproline) was carried out in an accredited laboratory. The results of our study have demonstrated that the incorporation of mealworms into sausages, particularly through freeze-drying, increased fat content and enhanced the profile of FA, including omega-3s while reducing protein and cholesterol levels, and altering collagen content, suggesting improved nutritional value and potential health benefits without compromising the safety of the product. Therefore, we are highlighting that the addition of mealworms influences the quality of amino acids positively and maintains biogenic amine levels within safe limits, alongside a negligible impact on nitrates and nitrites and a reduction in peroxide values. These findings indicate an overall improvement in sausage quality and safety without compromising safety.

Metabolomic Markers in Attention-Deficit/Hyperactivity Disorder (ADHD) among Children and Adolescents-A Systematic Review

Attention-Deficit/Hyperactivity Disorder (ADHD), characterized by clinical diversity, poses diagnostic challenges often reliant on subjective assessments. Metabolomics presents an objective approach, seeking biomarkers for precise diagnosis and targeted interventions. This review synthesizes existing metabolomic insights into ADHD, aiming to reveal biological mechanisms and diagnostic potentials. A thorough PubMed and Web of Knowledge search identified studies exploring blood/urine metabolites in ADHD-diagnosed or psychometrically assessed children and adolescents. Synthesis revealed intricate links between ADHD and altered amino acid metabolism, neurotransmitter dysregulation (especially dopamine and serotonin), oxidative stress, and the kynurenine pathway impacting neurotransmitter homeostasis. Sleep disturbance markers, notably in melatonin metabolism, and stress-induced kynurenine pathway activation emerged. Distinct metabolic signatures, notably in the kynurenine pathway, show promise as potential diagnostic markers. Despite limitations like participant heterogeneity, this review underscores the significance of integrated therapeutic approaches targeting amino acid metabolism, neurotransmitters, and stress pathways. While guiding future research, this overview of the metabolomic findings in ADHD suggests directions for precision diagnostics and personalized ADHD interventions.

Identification of key neuronal mechanisms triggered by dimethyl fumarate in SH-SY5Y human neuroblastoma cells through a metabolomic approach

Dimethyl fumarate (DMF) is an old drug used for psoriasis treatment that has recently been repurposed to treat relapse-remitting multiple sclerosis, mostly due to its neuro- and immunomodulatory actions. However, mining of a pharmacovigilance database recently ranked DMF as the second pharmaceutical most associated with cognitive adverse events. To our best knowledge, the signaling mechanisms underlying its therapeutic and neurotoxic outcomes remain mostly undisclosed. This work thus represents the first-hand assessment of DMF-induced metabolic changes in undifferentiated SH-SY5Y human neuroblastoma cells, through an untargeted metabolomic approach using gas chromatography-mass spectrometry (GC-MS). The endometabolome was analyzed following 24 h and 96 h of exposure to two pharmacologically relevant DMF concentrations (0.1 and 10 μM). None of these conditions significantly reduced metabolic activity (MTT reduction assay). Our data showed that 24 h-exposure to DMF at both concentrations tested mainly affected metabolic pathways involved in mitochondrial activity (e.g., citric acid cycle, de novo triacylglycerol biosynthesis), and the synthesis of catecholamines and serotonin by changing the levels of their respective precursors, namely phenylalanine (0.68-fold decrease for 10 μM DMF vs vehicle), and tryptophan (1.36-fold increase for 0.1 μM DMF vs vehicle). Interestingly, taurine, whose levels can be modulated via Nrf2 signaling (DMF's primary target), emerged as a key mediator of DMF's neuronal action, displaying a 3.86-fold increase and 0.27-fold decrease for 10 μM DMF at 24 h and 96 h, respectively. A 96 h-exposure to DMF seemed to mainly trigger pathways associated with glucose production (e.g., gluconeogenesis, glucose-alanine cycle, malate-aspartate shuttle), possibly related to the metabolism of DMF into monomethyl fumarate and its further conversion into glucose via activation of the citric acid cycle. Overall, our data contribute to improving the understanding of the events associated with neuronal exposure to DMF.

Comparative secretome metabolic dysregulation by six engineered dietary nanoparticles (EDNs) on the simulated gut microbiota

The potential use of engineered dietary nanoparticles (EDNs) in diet has been increasing and poses a risk of exposure. The effect of EDNs on gut bacterial metabolism remains largely unknown. In this study, liquid chromatography-mass spectrometry (LC-MS) based metabolomics was used to reveal significantly altered metabolites and metabolic pathways in the secretome of simulated gut microbiome exposed to six different types of EDNs (Chitosan, cellulose nanocrystals (CNC), cellulose nanofibrils (CNF) and polylactic-co-glycolic acid (PLGA); two inorganic EDNs including TiO2 and SiO2) at two dietary doses. We demonstrated that all six EDNs can alter the composition in the secretome with distinct patterns. Chitosan, followed by PLGA and SiO2, has shown the highest potency in inducing the secretome change with major pathways in tryptophan and indole metabolism, bile acid metabolism, tyrosine and phenol metabolism. Metabolomic alterations with clear dose response were observed in most EDNs. Overall, phenylalanine has been shown as the most sensitive metabolites, followed by bile acids such as chenodeoxycholic acid and cholic acid. Those metabolites might be served as the representative metabolites for the EDNs-gut bacteria interaction. Collectively, our studies have demonstrated the sensitivity and feasibility of using metabolomic signatures to understand and predict EDNs-gut microbiome interaction.

Spatial amine metabolomics and histopathology reveal localized brain alterations in subacute traumatic brain injury and the underlying mechanism of herbal treatment

INTRODUCTION

Spatial changes of amine metabolites and histopathology of the whole brain help to reveal the mechanism of traumatic brain injury (TBI) and treatment.

METHODS

A newly developed liquid microjunction surface sampling-tandem mass tag-ultra performance liquid chromatography-mass spectrometry technique is applied to profile brain amine metabolites in five brain regions after impact-induced TBI at the subacute stage. H&E, Nissl, and immunofluorescence staining are performed to spatially correlate microscopical changes to metabolic alterations. Then, bioinformatics, molecular docking, ELISA, western blot, and immunofluorescence are integrated to uncover the mechanism of Xuefu Zhuyu decoction (XFZYD) against TBI.

RESULTS

Besides the hippocampus and cortex, the thalamus, caudate-putamen, and fiber tracts also show differentiated metabolic changes between the Sham and TBI groups. Fourteen amine metabolites (including isomers such as L-leucine and L-isoleucine) are significantly altered in specific regions. The metabolic changes are well matched with the degree of neuronal damage, glia activation, and neurorestoration. XFZYD reverses the dysregulation of several amine metabolites, such as hippocampal Lys-Phe/Phe-Lys and dopamine. Also, XFZYD enhances post-TBI angiogenesis in the hippocampus and the thalamus.

CONCLUSION

This study reveals the local amine-metabolite and histological changes in the subacute stage of TBI. XFZYD may promote TBI recovery by normalizing amine metabolites and spatially promoting dopamine production and angiogenesis.

Impact of prolonged storage on quality assessment properties and constituents of honey: A systematic review

This systematic review paper aims to discuss the trend in quality assessment properties and constituents of honey at different storage conditions and confer the possible whys and wherefores associated with the significant changes. Initially, a literature search was conducted through Google Scholar, ScienceDirect, PubMed, and Scopus databases. In total, 43 manuscripts published between 2001 and 2023 that met the inclusion and exclusion criteria were chosen for the review. As an outcome of this review, prolonged honey storage could deteriorate sensory, nutritional, and antioxidant properties and promote fermentation, granulation, microbial growth, carcinogenicity, organotoxicity, and nephrotoxicity. This systematic review also recognized that diastase activity, invertase activity, 5-hydroxymethylfurfural content, proline content, sugar content, amino acids, and vitamins could be used as indicators to distinguish fresh and stored honey based on the significant test (p-value) in the reported studies. However, all the reported studies used the simplest approach (one-way ANOVA) to identify the significant differences in the analyzed parameter during the storage period and none of them reported an approach to identify the most influential parameter at different storage conditions. In conclusion, orthogonal partial least squares discriminant analysis (supervised multivariate statistical tool) has to be employed in future studies to find the most influential parameter and could be used to potent chemical markers to distinguish fresh and stored honey because this analysis is incorporated with S-plot, variable importance of projection, and one-way ANOVA, which can produce the most accurate and precise results rather solely depending on one-way ANOVA.

Salivary Biomarkers for Alzheimer's Disease: A Systematic Review with Meta-Analysis

Alzheimer's Disease (AD) is the most common neurodegenerative disease which manifests with progressive cognitive impairment, leading to dementia. Considering the noninvasive collection of saliva, we designed the systematic review to answer the question "Are salivary biomarkers reliable for the diagnosis of Alzheimer's Disease?" Following the inclusion and exclusion criteria, 30 studies were included in this systematic review (according to the PRISMA statement guidelines). Potential biomarkers include mainly proteins, metabolites and even miRNAs. Based on meta-analysis, in AD patients, salivary levels of beta-amyloid42 and p-tau levels were significantly increased, and t-tau and lactoferrin were decreased at borderline statistical significance. However, according to pooled AUC, lactoferrin and beta-amyloid42 showed a significant predictive value for salivary-based AD diagnosis. In conclusion, potential markers such as beta-amyloid42, tau and lactoferrin can be detected in the saliva of AD patients, which could reliably support the early diagnosis of this neurodegenerative disease.

Branched-chain amino acids as adjunctive-alternative treatment in patients with autism: a pilot study

The branched-chain amino acid (BCAA) is a group of essential amino acids that are involved in maintaining the energy balance of a human being as well as the homoeostasis of GABAergic, glutamatergic, serotonergic and dopaminergic systems. Disruption of these systems has been associated with the pathophysiology of autism while low levels of these amino acids have been discovered in patients with autism. A pilot open-label, prospective, follow-up study of the use of BCAA in children with autistic behaviour was carried out. Fifty-five children between the ages of 6 and 18 participated in the study from May 2015 to May 2018. We used a carbohydrate-free BCAA-powdered mixture containing 45·5 g of leucine, 30 g of isoleucine and 24·5 g of valine in a daily dose of 0·4 g/kg of body weight which was administered every morning. Following the initiation of BCAA administration, children were submitted to a monthly psychological examination. Beyond the 4-week mark, BCAA were given to thirty-two people (58·18 %). Six of them (10·9 %) discontinued after 4-10 weeks owing to lack of improvement. The remaining twenty-six children (47·27 %) who took BCAA for longer than 10 weeks displayed improved social behaviour and interactions, as well as improvements in their speech, cooperation, stereotypy and, principally, their hyperactivity. There were no adverse reactions reported during the course of the treatment. Although these data are preliminary, there is some evidence that BCAA could be used as adjunctive treatment to conventional therapeutic methods for the management of autism.

Plasma amino acids in major depressive disorder: between pathology to pharmacology

Addressing the formidable challenge posed by the development of effective and personalized interventions for major depressive disorder (MDD) necessitates a comprehensive comprehension of the intricate role that plasma amino acids play and their implications in MDD pathology and pharmacology. Amino acids, owing to their indispensable functions in neurotransmission, metabolism, and immune regulation, emerge as pivotal entities in this intricate disorder. Our primary objective entails unraveling the underlying mechanisms and unveiling tailored treatments through a meticulous investigation into the interplay between plasma amino acids, MDD, and pharmacological strategies. By conducting a thorough and exhaustive review of the existing literature, we have identified pertinent studies on plasma amino acids in MDD, thereby uncovering noteworthy disturbances in the profiles of amino acids among individuals afflicted by MDD when compared to their healthy counterparts. Specifically, disruptions in the metabolism of tryptophan, phenylalanine, and tyrosine, which serve as precursors to essential neurotransmitters, have emerged as prospective biomarkers and critical contributors to the pathophysiology of depression. Amnio acids play an essential role in MDD and could represent an attractive pharmacological target, more studies are further required to fully reveal their underlying mechanisms.

Quantifying acute changes in neurometabolism following blast-induced traumatic brain injury

Brain health is largely dependent on the metabolic regulation of amino acids. Brain injuries, diseases, and disorders can be detected through alterations in free amino acid (FAA) concentrations; and thus, mapping the changes has high diagnostic potential. Common methods focus on optimizing neurotransmitter quantification; however, recent focus has expanded to investigate the roles of molecular precursors in brain metabolism. An isocratic method using high performance liquid chromatography with electrochemical cell detection was developed to quantify a wide range of molecular precursors and neurotransmitters: alanine, arginine, aspartate, serine, taurine, threonine, tyrosine, glycine, glutamate, glutamine, and γ-Aminobutyric acid (GABA) following traumatic brain injury. First, baseline concentrations were determined in the serum, cerebrospinal fluid, hippocampus, cortex, and cerebellum of naïve male Sprague Dawley rats. A subsequent study was performed investigating acute changes in FAA concentrations following blast-induced traumatic brain injury (bTBI). Molecular precursor associated FAAs decreased in concentration at 4 h after injury in both the cortex and hippocampus while those serving as neurotransmitters remained unchanged. In particular, the influence of oxidative stress on the observed changes within alanine and arginine pathways following bTBI should be further investigated to elucidate the full therapeutic potential of these molecular precursors at acute time points.

Predictive Ability of Serum Amino Acid Levels to Differentiate Fibromyalgia Patients from Healthy Subjects

BACKGROUND

Fibromyalgia is a complex illness to diagnose and treat.

OBJECTIVES

To evaluate a broad range of circulating free amino acid (AA) levels in fibromyalgia patients as well as the ability of the AAs to differentiate fibromyalgia patients from healthy subjects.

DESIGN

We carried out a case-control study to evaluate AA levels in 62 patients with fibromyalgia and 78 healthy subjects. This study adheres to the STROBE guidelines.

METHODS

AAs content was assayed by HPLC in serum samples. The predictive value of AA levels in fibromyalgia was determined by receiver operating characteristic (ROC) curve and forward binary logistic regression analyses.

RESULTS

Fibromyalgia patients showed higher serum levels of aspartic acid, glutamic acid, aminoadipic acid, asparagine, histidine, 3-methyl-histidine, 5-methyl-histidine, glycine, threonine, taurine, tyrosine, valine, methionine, isoleucine, phenylalanine, leucine, ornithine, lysine, branched chain AAs (BCAAs), large neutral AAs, essential AAs (EAAs), non-essential AAs (NEAAs), basic AAs, EAAs/NEAAs ratio, phenylalanine/tyrosine ratio, and global arginine bioavailability ratio than the controls. Serum alanine levels were lower in patients than in controls. According to ROC analysis, most of these AAs may be good markers for differentiating individuals with fibromyalgia from healthy subjects. Results of logistic regression showed that the combination of glutamic acid, histidine, and alanine had the greatest predictive ability to diagnose fibromyalgia.

CONCLUSIONS

Our results show an imbalance in serum levels of most AAs in patients with fibromyalgia, which suggest a metabolic disturbance. The determination of serum levels of these AAs may aid in the diagnosis of fibromyalgia, in combination with clinical data of the patient.

Edible Herbal Medicines as an Alternative to Common Medication for Sleep Disorders: A Review Article

Insomnia is repeated difficulty in falling asleep, maintaining sleep, or experiencing lowquality sleep, resulting in some form of daytime disturbance. Sleeping disorders cause daytime fatigue, mental confusion, and over-sensitivity due to insufficient recovery from a sound sleep. There are some drugs, such as benzodiazepines and anti-histaminic agents, which help to sleep induction and insomnia cure. However, the prolonged administration is unsuitable because of tolerance and dependence. Therefore, the researchers attempt to find new medicines with lesser adverse effects. Natural products have always been good sources for developing new therapeutics for managing diseases such as cancer, cardiovascular disease, diabetes, insomnia, and liver and renal problems. Ample research has justified the acceptable reason and relevance of the use of these herbs in the treatment of insomnia. It is worth noting that in this study, we looked into various Persian herbs in a clinical trial and in vivo to treat insomnia, such as Artemisia annua, Salvia reuterana, Viola tricolor, Passiflora incarnata, lettuce, and Capparis spinose. According to research, herb extracts and fractions, particularly n-butanol fractions with non-polar agents, impact the benzodiazepine receptors and have hypnotic properties. Also, alkaloids, glycosides, flavonoids, saponins, and tannins in practically every plant are mentioned making them the popular natural compounds to help with sleep disorders and promote calmness.

Metabolic profiling of Alzheimer's disease: Untargeted metabolomics analysis of plasma samples

Alzheimer's disease (AD) is often not recognized or is diagnosed very late, which significantly reduces the effectiveness of available pharmacological treatments. Metabolomic analyzes have great potential for improving existing knowledge about the pathogenesis and etiology of AD and represent a novel approach towards discovering biomarkers that could be used for diagnosis, prognosis, and therapy monitoring. In this study, we applied the untargeted metabolomic approach to investigate the changes in biochemical pathways related to AD pathology. We used gas chromatography and liquid chromatography coupled to mass spectrometry (GC-MS and LC-MS, respectively) to identify metabolites whose levels have changed in subjects with AD diagnosis (N = 40) compared to healthy controls (N = 40) and individuals with mild cognitive impairment (MCI, N = 40). The GC-MS identified significant differences between groups in levels of metabolites belonging to the classes of benzene and substituted derivatives, carboxylic acids and derivatives, fatty acyls, hydroxy acids and derivatives, keto acids and derivatives, and organooxygen compounds. Most of the compounds identified by the LC-MS were various fatty acyls, glycerolipids and glycerophospholipids. All of these compounds were decreased in AD patients and in subjects with MCI compared to healthy controls. The results of the study indicate disturbed metabolism of lipids and amino acids and an imbalance of metabolites involved in energy metabolism in individuals diagnosed with AD, compared to healthy controls and MCI subjects.

Identifying subgroups of childhood obesity by using multiplatform metabotyping

Introduction: Obesity results from an interplay between genetic predisposition and environmental factors such as diet, physical activity, culture, and socioeconomic status. Personalized treatments for obesity would be optimal, thus necessitating the identification of individual characteristics to improve the effectiveness of therapies. For example, genetic impairment of the leptin-melanocortin pathway can result in rare cases of severe early-onset obesity. Metabolomics has the potential to distinguish between a healthy and obese status; however, differentiating subsets of individuals within the obesity spectrum remains challenging. Factor analysis can integrate patient features from diverse sources, allowing an accurate subclassification of individuals. Methods: This study presents a workflow to identify metabotypes, particularly when routine clinical studies fail in patient categorization. 110 children with obesity (BMI > +2 SDS) genotyped for nine genes involved in the leptin-melanocortin pathway (CPE, MC3R, MC4R, MRAP2, NCOA1, PCSK1, POMC, SH2B1, and SIM1) and two glutamate receptor genes (GRM7 and GRIK1) were studied; 55 harboring heterozygous rare sequence variants and 55 with no variants. Anthropometric and routine clinical laboratory data were collected, and serum samples processed for untargeted metabolomic analysis using GC-q-MS and CE-TOF-MS and reversed-phase U(H)PLC-QTOF-MS/MS in positive and negative ionization modes. Following signal processing and multialignment, multivariate and univariate statistical analyses were applied to evaluate the genetic trait association with metabolomics data and clinical and routine laboratory features. Results and Discussion: Neither the presence of a heterozygous rare sequence variant nor clinical/routine laboratory features determined subgroups in the metabolomics data. To identify metabolomic subtypes, we applied Factor Analysis, by constructing a composite matrix from the five analytical platforms. Six factors were discovered and three different metabotypes. Subtle but neat differences in the circulating lipids, as well as in insulin sensitivity could be established, which opens the possibility to personalize the treatment according to the patients categorization into such obesity subtypes. Metabotyping in clinical contexts poses challenges due to the influence of various uncontrolled variables on metabolic phenotypes. However, this strategy reveals the potential to identify subsets of patients with similar clinical diagnoses but different metabolic conditions. This approach underscores the broader applicability of Factor Analysis in metabotyping across diverse clinical scenarios.

Traumatic brain injury, abnormal growth hormone secretion, and gut dysbiosis

The gut microbiome has been implicated in a variety of neuropathologies with recent data suggesting direct effects of the microbiome on host metabolism, hormonal regulation, and pathophysiology. Studies have shown that gut bacteria impact host growth, partially mediated through the growth hormone (GH)/insulin-like growth factor 1 (IGF-1) axis. However, no study to date has examined the specific role of GH on the fecal microbiome (FMB) or the changes in this relationship following a traumatic brain injury (TBI). Current literature has demonstrated that TBI can lead to either temporary or sustained abnormal GH secretion (aGHS). More recent literature has suggested that gut dysbiosis may contribute to aGHS leading to long-term sequelae now known as brain injury associated fatigue and cognition (BIAFAC). The aGHS observed in some TBI patients presents with a symptom complex including profound fatigue and cognitive dysfunction that improves significantly with exogenous recombinant human GH treatment. Notably, GH treatment is not curative as fatigue and cognitive decline typically recur upon treatment cessation, indicating the need for additional studies to address the underlying mechanistic cause.

Fish oil supplementation counteracts the effect of high-fat and high-sucrose diets on the carbonylated proteome in the rat cerebral cortex

High daily intake of saturated fats and refined carbohydrates, which often leads to obesity and overweight, has been associated with cognitive impairment, premature brain aging and the aggravation of neurodegenerative diseases. Although the molecular pathology of obesity-related brain damage is not fully understood, the increased levels of oxidative stress induced by the diet seem to be definitively involved. Being protein carbonylation determinant for protein activity and function and a main consequence of oxidative stress, this study aims to investigate the effect of the long-term high-fat and sucrose diet intake on carbonylated proteome of the cerebral cortex of Sprague-Dawley rats. To achieve this goal, the study identified and quantified the carbonylated proteins and lipid peroxidation products in the cortex, and correlated them with biometrical, biochemical and other redox status parameters. Results demonstrated that the obesogenic diet selectively increased oxidative damage of specific proteins that participate in fundamental pathways for brain function, i.e. energy production, glucose metabolism and neurotransmission. This study also evaluated the antioxidant properties of fish oil to counteract diet-induced brain oxidative damage. Fish oil supplementation demonstrated a stronger capacity to modulate carbonylated proteome in the brain cortex. Data indicated that fish oils did not just decrease carbonylation of proteins affected by the obesogenic diet, but also decreased the oxidative damage of other proteins participating in the same metabolic functions, reinforcing the beneficial effect of the supplement on those pathways. The results could help contribute to the development of successful nutritional-based interventions to prevent cognitive decline and promote brain health.

Fluorescent-Based Neurotransmitter Sensors: Present and Future Perspectives

Neurotransmitters (NTs) are endogenous low-molecular-weight chemical compounds that transmit synaptic signals in the central nervous system. These NTs play a crucial role in facilitating signal communication, motor control, and processes related to memory and learning. Abnormalities in the levels of NTs lead to chronic mental health disorders and heart diseases. Therefore, detecting imbalances in the levels of NTs is important for diagnosing early stages of diseases associated with NTs. Sensing technologies detect NTs rapidly, specifically, and selectively, overcoming the limitations of conventional diagnostic methods. In this review, we focus on the fluorescence-based biosensors that use nanomaterials such as metal clusters, carbon dots, and quantum dots. Additionally, we review biomaterial-based, including aptamer- and enzyme-based, and genetically encoded biosensors. Furthermore, we elaborate on the fluorescence mechanisms, including fluorescence resonance energy transfer, photon-induced electron transfer, intramolecular charge transfer, and excited-state intramolecular proton transfer, in the context of their applications for the detection of NTs. We also discuss the significance of NTs in human physiological functions, address the current challenges in designing fluorescence-based biosensors for the detection of NTs, and explore their future development.

Simultaneous, Real-Time Detection of Glutamate and Dopamine in Rat Striatum Using Fast-Scan Cyclic Voltammetry

Glutamate and dopamine (DA) represent two key contributors to striatal functioning, a region of the brain that is essential to motor coordination and motivated behavior. While electroanalytical techniques can be utilized for rapid, spatially resolved detection of DA in the interferent-rich brain environment, glutamate, a nonelectroactive analyte, cannot be directly detected using electroanalytical techniques. However, it can be probed using enzyme-based sensors, which generate an electroactive reporter in the presence of glutamate. The vast majority of glutamate biosensors have relied on amperometric sensing, which is an inherently nonselective detection technique. This approach necessitates the use of complex and performance-limiting modifications to ensure the desired single-analyte specificity. Here, we present a novel glutamate microbiosensor fabricated on a carbon-fiber microelectrode substrate and coupled with fast-scan cyclic voltammetry (FSCV) to enable the simultaneous quantification of glutamate and DA at single recording sites in the brain, which is impossible when using typical amperometric approaches. The glutamate microbiosensors were characterized for sensitivity, stability, and selectivity by using a voltammetric waveform optimized for the simultaneous detection of both species. The applicability of these sensors for the investigation of neural circuits was validated in the rat ventral striatum. Electrically evoked glutamate and DA release were recorded at single-micrometer-scale locations before and after pharmacological manipulation of glutamatergic signaling. Our novel glutamate microbiosensor advances the state of the art by providing a powerful tool for probing coordination between these two species in a way that has previously not been possible.

Systemic perturbations in amino acids/amino acid derivatives and tryptophan pathway metabolites associated with murine influenza A virus infection

BACKGROUND

Influenza A virus (IAV) is the only influenza virus causing flu pandemics (i.e., global epidemics of flu disease). Influenza (the flu) is a highly contagious disease that can be deadly, especially in high-risk groups. Worldwide, these annual epidemics are estimated to result in about 3 to 5 million cases of severe illness and in about 290,000 to 650,000 respiratory deaths. We intend to reveal the effect of IAV infection on the host's metabolism, immune response, and neurotoxicity by using a mouse IAV infection model.

METHODS

51 metabolites of murine blood plasma (33 amino acids/amino acid derivatives (AADs) and 18 metabolites of the tryptophan pathway) were analyzed by using Ultra-High-Performance Liquid Chromatography-Mass Spectrometry with Electrospray Ionization at the acute (7 days post-infection (dpi)), resolution (14 dpi), and recovery (21 dpi) stages of the virus infection in comparison with controls.

RESULTS

Among the 33 biogenic amino acids/AADs, the levels of five amino acids/AADs (1-methylhistidine, 5-oxoproline, α-aminobutyric acid, glutamine, and taurine) increased by 7 dpi, whereas the levels of ten amino acids/AADs (4-hydroxyproline, alanine, arginine, asparagine, cysteine, citrulline, glycine, methionine, proline, and tyrosine) decreased. By 14 dpi, the levels of one AAD (3-methylhistidine) increased, whereas the levels of five amino acids/AADs (α-aminobutyric acid, aminoadipic acid, methionine, threonine, valine) decreased. Among the 18 metabolites from the tryptophan pathway, the levels of kynurenine, quinolinic acid, hydroxykynurenine increased by 7 dpi, whereas the levels of indole-3-acetic acid and nicotinamide riboside decreased.

CONCLUSIONS

Our data may facilitate understanding the molecular mechanisms of host responses to IAV infection and provide a basis for discovering potential new mechanistic, diagnostic, and prognostic biomarkers and therapeutic targets for IAV infection.

Neuromodulators as Interdomain Signaling Molecules Capable of Occupying Effector Binding Sites in Bacterial Transcription Factors

Hormones and neurotransmitters are important components of inter-kingdom signaling systems that ensure the coexistence of eukaryotes with their microbial community. Their ability to affect bacterial physiology, metabolism, and gene expression was evidenced by various experimental approaches, but direct penetration into bacteria has only recently been reported. This opened the possibility of considering neuromodulators as potential effectors of bacterial ligand-dependent regulatory proteins. Here, we assessed the validity of this assumption for the neurotransmitters epinephrine, dopamine, and norepinephrine and two hormones (melatonin and serotonin). Using flexible molecular docking for transcription factors with ligand-dependent activity, we assessed the ability of neuromodulators to occupy their effector binding sites. For many transcription factors, including the global regulator of carbohydrate metabolism, CRP, and the key regulator of lactose assimilation, LacI, this ability was predicted based on the analysis of several 3D models. By occupying the ligand binding site, neuromodulators can sterically hinder the interaction of the target proteins with the natural effectors or even replace them. The data obtained suggest that the direct modulation of the activity of at least some bacterial transcriptional factors by neuromodulators is possible. Therefore, the natural hormonal background may be a factor that preadapts bacteria to the habitat through direct perception of host signaling molecules.

Metabolomics in severe traumatic brain injury: a scoping review

BACKGROUND

Diagnosis and prognostication of severe traumatic brain injury (sTBI) continue to be problematic despite years of research efforts. There are currently no clinically reliable biomarkers, though advances in protein biomarkers are being made. Utilizing Omics technology, particularly metabolomics, may provide new diagnostic biomarkers for sTBI. Several published studies have attempted to determine the specific metabolites and metabolic pathways involved; these studies will be reviewed.

AIMS

This scoping review aims to summarize the current literature concerning metabolomics in sTBI, review the comprehensive data, and identify commonalities, if any, to define metabolites with potential clinical use. In addition, we will examine related metabolic pathways through pathway analysis.

METHODS

Scoping review methodology was used to examine the current literature published in Embase, Scopus, PubMed, and Medline. An initial 1090 publications were identified and vetted with specific inclusion criteria. Of these, 20 publications were selected for further examination and summary. Metabolic data was classified using the Human Metabolome Database (HMDB) and arranged to determine the 'recurrent' metabolites and classes found in sTBI. To help understand potential mechanisms of injury, pathway analysis was performed using these metabolites and the Kyoto Encyclopedia of Genes and Genomes (KEGG) Pathway Database.

RESULTS

Several metabolites related to sTBI and their effects on biological pathways were identified in this review. Across the literature, proline, citrulline, lactate, alanine, valine, leucine, and serine all decreased in adults post sTBI, whereas both octanoic and decanoic acid increased. Hydroxy acids and organooxygen compounds generally increased following sTBI, while most carboxylic acids decreased. Pathway analysis showed significantly affected glycine and serine metabolism, glycolysis, branched-chain amino acid (BCAA) metabolism, and other amino acid metabolisms. Interestingly, no tricarboxylic acid cycle metabolites were affected.

CONCLUSION

Aside from a select few metabolites, classification of a metabolic profile proved difficult due to significant ambiguity between study design, sample size, type of sample, metabolomic detection techniques, and other confounding variables found in sTBI literature. Given the trends found in some studies, further metabolomics investigation of sTBI may be useful to identify clinically relevant metabolites.

Plasma Amino Acid Neurotransmitters and Ischemic Stroke Prognosis: A Multicenter Prospective Study

BACKGROUND

Plasma amino acid neurotransmitter dysregulation is suggested to be implicated in the development of ischemic stroke, but its prognostic value for ischemic stroke remains controversial.

OBJECTIVE

We aimed to prospectively investigate the associations between plasma amino acid neurotransmitters levels and adverse outcomes after ischemic stroke in a large-scale multicenter cohort study.

METHODS

We measured 4 plasma amino acid neurotransmitters (glutamic acid, aspartic acid, gamma-aminobutyric acid, and glycine) among 3486 patients with ischemic stroke from 26 hospitals across China. The primary outcome is the composite outcome of death or major disability (modified Rankin Scale score ≥3) at 3 mo after ischemic stroke.

RESULTS

After multivariate adjustment, the odds ratios of death or major disability for the highest versus the lowest quartile were 2.04 (95% confidence interval [CI]: 1.60,2.59; P-trend < 0.001) for glutamic acid, 2.03 (95% CI: 1.59, 2.59; P-trend < 0.001) for aspartic acid, 1.35 (95% CI: 1.06, 1.71; P-trend = 0.016) for gamma-aminobutyric acid, and 0.54 (95% CI: 0.42, 0.69; P-trend < 0.001) for glycine. Each standard deviation increment of log-transformed glutamic acid, aspartic acid, gamma-aminobutyric acid, and glycine was associated with a 34%, 34%, and 9% increased risk, and a 23% decreased risk of death or major disability, respectively (all P < 0.05), in a linear fashion as indicated by spline regression analyses (all P for linearity < 0.05). Addition of the 4 plasma amino acid neurotransmitters to conventional risk factors significantly improved the risk reclassification, as evidenced by integrated discrimination improvement and net reclassification improvement (all P < 0.05).

CONCLUSIONS

Increased glutamic acid, aspartic acid, and gamma-aminobutyric acid and decreased glycine in plasma are associated with adverse outcomes after ischemic stroke, suggesting that plasma amino acid neurotransmitters may be potential intervention targets for improving prognosis of ischemic stroke. The CATIS trial was registered at clinicaltrials.gov (registration number: NCT01840072; URL: ===https://clinicaltrials.gov/ct2/show/NCT01840072?cond=NCT01840072&draw=2&rank=1).

Schizophrenia-Like Behaviors Arising from Dysregulated Proline Metabolism Are Associated with Altered Neuronal Morphology and Function in Mice with Hippocampal PRODH Deficiency

Despite decades of research being conducted to understand what physiological deficits in the brain are an underlying basis of psychiatric diseases like schizophrenia, it has remained difficult to establish a direct causal relationship between neuronal dysfunction and specific behavioral phenotypes. Moreover, it remains unclear how metabolic processes, including amino acid metabolism, affect neuronal function and consequently modulate animal behaviors. PRODH, which catalyzes the first step of proline degradation, has been reported as a susceptibility gene for schizophrenia. It has consistently been shown that PRODH knockout mice exhibit schizophrenia-like behaviors. However, whether the loss of PRODH directly impacts neuronal function or whether such neuronal deficits are linked to schizophrenia-like behaviors has not yet been examined. Herein, we first ascertained that dysregulated proline metabolism in humans is associated with schizophrenia. We then found that PRODH was highly expressed in the oreins layer of the mouse dorsal hippocampus. By using AAV- mediated shRNA, we depleted PRODH expression in the mouse dorsal hippocampus and subsequently observed hyperactivity and impairments in the social behaviors, learning, and memory of these mice. Furthermore, the loss of PRODH led to altered neuronal morphology and function both in vivo and in vitro. Our study demonstrates that schizophrenia-like behaviors may arise from dysregulated proline metabolism due to the loss of PRODH and are associated with altered neuronal morphology and function in mice.

Serum Amino Acid Profiling in Children with Autistic Spectrum Disorder: Insights from a Single-Center Study in Southern Romania

The objective of this study was to analyze the serum amino acid profile in children diagnosed with autistic spectrum disorder (ASD) in southern Romania. The analysis aimed to provide insights into the underlying metabolic dysregulations associated with ASD. ASD is a neurodevelopmental disorder characterized by impaired social interaction, communication deficits, and restricted repetitive behaviors. Although the exact cause of ASD is largely unknown, recent evidence suggests that abnormalities in amino acid metabolism may contribute to its pathogenesis. Therefore, studying the amino acid profile in children with ASD could offer valuable information for understanding the metabolic disturbances associated with this complex disorder. This single-center study examined serum samples from children diagnosed with ASD, utilizing advanced analytical techniques to quantify the levels of different amino acids, amino acid derivatives, and amino acid-like substances. The results showed a lower level of taurine and a higher level of asparagine and leucine in the ASD group versus the control group. In the ASD group, we observed significant differences in tryptophan and alpha-aminobutyric acid levels based on age, with higher tryptophan levels in children older than 7 years when compared to children younger than 7 years; however, no significant correlations were found with the ASD group older than 7 years old. Additionally, younger children with ASD exhibited higher levels of alpha-aminobutyric acid than older children with ASD. The findings from this study contribute to the growing body of knowledge on the metabolic aspects of ASD, highlighting potential biomarkers and therapeutic targets for improving the management and treatment of ASD in children.

Determination of underivatized amino acids in human plasma using ion pair liquid chromatography/tandem mass spectrometry

Accurate quantification of amino acids (AA) is essential for several applications, including clinical research, food analysis, and pharmaceutical studies. In this study, we developed an analytical method based on liquid chromatography with electrospray ionization coupled to tandem mass spectrometry detection (LC-ESI-MS/MS). This method was devised to accurately quantify a spectrum of amino acids, notably taurine, creatinine, glutathione (GSH), and sulfur-containing amino acids (SAAs) such as methionine, cysteine, and homocysteine, using only 10 μL of human plasma. A stable isotope derivative of each AA is used as an internal standard (IS) for accurate quantification. For retention and separation on a C18 column, heptafluorobutyric acid (HFBA) was employed as an ion pair agent. Multiple reaction monitoring (MRM) in positive mode with the precursor-to-product ion transitions at m/z is used for quantification. The method showed excellent linearity for all AA with a high correlation coefficient (r > 0.9927). The linear fit indicates that the detector response is linear over the tested range of standard concentrations. The accuracy and precision of the method were within the acceptable range of 92-110% and < 15%, respectively. The limit of detection (LOD) and limit of quantification (LOQ) were in the range of 0.001-1.80 µM and 0.004-6.0 µM, respectively. No significant ion suppression or carry over was observed. In conclusion, the assay was validated and found to have adequate accuracy, precision, linearity, sensitivity and selectivity. The assay has been successfully applied to the analysis of human plasma.

Transition metal ions and neurotransmitters: coordination chemistry and implications for neurodegeneration

Neurodegeneration is characterized by a disturbance in neurotransmitter-mediated signaling pathways. Recent studies have highlighted the significant role of transition metal ions, including Cu(i/ii), Zn(ii), and Fe(ii/iii), in neurotransmission, thereby making the coordination chemistry of neurotransmitters a growing field of interest in understanding signal dysfunction. This review outlines the physiological functions of transition metal ions and neurotransmitters, with the metal-binding properties of small molecule-based neurotransmitters and neuropeptides. Additionally, we discuss the structural and conformational changes of neurotransmitters induced by redox-active metal ions, such as Cu(i/ii) and Fe(ii/iii), and briefly describe the outcomes arising from their oxidation, polymerization, and aggregation. These observations have important implications for neurodegeneration and emphasize the need for further research to develop potential therapeutic strategies.

Multi-level analysis of the gut-brain axis shows autism spectrum disorder-associated molecular and microbial profiles

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by heterogeneous cognitive, behavioral and communication impairments. Disruption of the gut-brain axis (GBA) has been implicated in ASD although with limited reproducibility across studies. In this study, we developed a Bayesian differential ranking algorithm to identify ASD-associated molecular and taxa profiles across 10 cross-sectional microbiome datasets and 15 other datasets, including dietary patterns, metabolomics, cytokine profiles and human brain gene expression profiles. We found a functional architecture along the GBA that correlates with heterogeneity of ASD phenotypes, and it is characterized by ASD-associated amino acid, carbohydrate and lipid profiles predominantly encoded by microbial species in the genera Prevotella, Bifidobacterium, Desulfovibrio and Bacteroides and correlates with brain gene expression changes, restrictive dietary patterns and pro-inflammatory cytokine profiles. The functional architecture revealed in age-matched and sex-matched cohorts is not present in sibling-matched cohorts. We also show a strong association between temporal changes in microbiome composition and ASD phenotypes. In summary, we propose a framework to leverage multi-omic datasets from well-defined cohorts and investigate how the GBA influences ASD.

Synthesis, Characterization, and Antibacterial Activity of Ni-Substituted Krebs-type Sandwich-Tungstobismuthates Functionalized with Amino Acids

Four new Ni-substituted Krebs-type sandwich-tungstobismuthates, K₄Ni₂[{Ni(β-ala)(H₂O)₂}₂{Ni(H₂O)}₂{Ni(H₂O)(η²-β-ala)}₂(B-β-BiW₉O₃₃)₂]·49H₂O {(β-ala)₄(Ni₃)₂(BiW₉)₂}, K_3.5Na_6.5[{Ni(η³-L-asp)}₂(WO₂)₂(B-β-BiW₉O₃₃)₂]·36H₂O·L-asp {(L-asp)₂(NiW)₂(BiW₉)₂}, K₄Na₆[{Ni(gly)(H₂O)₂}₂(WO₂)₂(B-β-BiW₉O₃₃)₂]·86H₂O {(gly)₂(NiW)₂(BiW₉)₂}, and K₂Na₈[{Ni(η²-serinol) (H₂O)}₂{Ni(H₂O)₂}₂(B-β-BiW₉O₃₃)₂]·42H₂O {(serinol)₂Ni₄(BiW₉)₂} have been synthesized by one-pot solution methods. All compounds have been characterized in the solid state by single-crystal X-ray diffraction (SXRD), powder X-ray diffraction (PXRD), elemental and thermogravimetric analyses, and infrared spectroscopy (IR), as well as by UV-vis spectroscopy in solution. The antibacterial activity of all compounds was studied against four bacterial strains by the determination of the minimum inhibitory concentration (MIC). The results showed that only {(β-ala)₄(Ni₃)₂(BiW₉)₂} demonstrates antibacterial activity (MIC is in the range from 8 to 256 μg/mL) compared to three other Ni-Krebs sandwiches.

Pharmacometabolic Effects of Pteryxin and Valproate on Pentylenetetrazole-Induced Seizures in Zebrafish Reveal Vagus Nerve Stimulation

Zebrafish (Danio rerio) assays provide a versatile pharmacological platform to test compounds on a wide range of behaviors in a whole organism. A major challenge lies in the lack of knowledge about the bioavailability and pharmacodynamic effects of bioactive compounds in this model organism. Here, we employed a combined methodology of LC-ESI-MS/MS analytics and targeted metabolomics with behavioral experiments to evaluate the anticonvulsant and potentially toxic effects of the angular dihydropyranocoumarin pteryxin (PTX) in comparison to the antiepileptic drug sodium valproate (VPN) in zebrafish larvae. PTX occurs in different Apiaceae plants traditionally used in Europe to treat epilepsy but has not been investigated so far. To compare potency and efficacy, the uptake of PTX and VPN into zebrafish larvae was quantified as larvae whole-body concentrations together with amino acids and neurotransmitters as proxy pharmacodynamic readout. The convulsant agent pentylenetetrazole (PTZ) acutely reduced the levels of most metabolites, including acetylcholine and serotonin. Conversely, PTX strongly reduced neutral essential amino acids in a LAT1 (SLCA5)-independent manner, but, similarly to VPN specifically increased the levels of serotonin, acetylcholine, and choline, but also ethanolamine. PTX dose and time-dependent manner inhibited PTZ-induced seizure-like movements resulting in a ~70% efficacy after 1 h at 20 µM (the equivalent of 4.28 ± 0.28 µg/g in larvae whole-body). VPN treated for 1 h with 5 mM (the equivalent of 18.17 ± 0.40 µg/g in larvae whole-body) showed a ~80% efficacy. Unexpectedly, PTX (1-20 µM) showed significantly higher bioavailability than VPN (0.1-5 mM) in immersed zebrafish larvae, possibly because VPN in the medium dissociated partially to the readily bioavailable valproic acid. The anticonvulsive effect of PTX was confirmed by local field potential (LFP) recordings. Noteworthy, both substances specifically increased and restored whole-body acetylcholine, choline, and serotonin levels in control and PTZ-treated zebrafish larvae, indicative of vagus nerve stimulation (VNS), which is an adjunctive therapeutic strategy to treat refractory epilepsy in humans. Our study demonstrates the utility of targeted metabolomics in zebrafish assays and shows that VPN and PTX pharmacologically act on the autonomous nervous system by activating parasympathetic neurotransmitters.

Cognitive and hippocampal effects of adult male mice exposure to environmentally relevant doses of phthalates

We recently showed that chronic exposure of adult male mice to environmental doses of DEHP alone or in a phthalate mixture altered blood brain barrier integrity and induced an inflammatory profile in the hippocampus. Here, we investigate whether such exposure alters hippocampus-dependent behavior and underlying cellular mechanisms. Adult C57BL/6 J male mice were continuously exposed orally to the vehicle or DEHP alone (5 or 50 μg/kg/d) or to DEHP (5 μg/kg/d) in a phthalate mixture. In the Morris water maze, males showed reduced latencies across days to find the platform in the cue and spatial reference memory tasks, regardless of their treatment group. In the probe test, DEHP-50 exposed males displayed a higher latency to find the platform quadrant. In the temporal order memory test, males exposed to DEHP alone or in a phthalate mixture were unable to discriminate between the most recently and previously seen objects. They also displayed reduced ability to show a preference for the new object in the novel object recognition test. These behavioral alterations were associated with a lowered dendritic spine density and protein levels of glutamate receptors and postsynaptic markers, and increased protein levels of the presynaptic synaptophysin in the hippocampus. Metabolomic analysis of the hippocampus indicated changes in amino acid levels including reduced tryptophan and L-kynurenine and elevated NAD + levels, respectively, a precursor, intermediate and endproduct of the kynurenine pathway of tryptophan metabolism. Interestingly, the protein amounts of the xenobiotic aryl hydrocarbon receptor, a target of this metabolic pathway, were elevated in the CA1 area. These data indicate that chronic exposure of adult male mice to environmental doses of DEHP alone or in a phthalate mixture impacted hippocampal function and structure, associated with modifications in amino acid metabolites with a potential involvement of the kynurenine pathway of tryptophan metabolism.

Nano-melatonin and-histidine modulate adipokines and neurotransmitters to improve cognition in HFD-fed rats: A formula to study

The established correlation between obesity and cognitive impairment portrays pharmacological products aimed at both disorders as an important therapeutic advance. Modulation of dysregulated adipokines and neurotransmitters is hence a critical aspect of the assessment of in-use drugs. At the cellular level, repairments in brain barrier integrity and cognitive flexibility are the main checkpoints. The aim of this study was to investigate whether melatonin and histidine, alone or in combination, could produce weight loss, meanwhile improve the cognitive processes. In this study, obese rat model was established by feeding high fat diet (HFD) composed of 25% fats (soybean oil) for 8 weeks, accompanied by melatonin (10 mg/kg), histidine (780 mg/kg), and combination of both in conventional form and nanoform. At the end of the study, adiposity hormones, neuronal monoamines and amino acids, brain derived neurotrophic factor (BDNF) and zonula occluden-1 (ZO-1) were assessed. HFD feeding resulted in significant weight gain and poor performance on cognitive test. Coadministration of histidine in the nanoform increased the level of ZO-1; an indicator of improving the brain barrier integrity, along with adjusting the adipokines and neurotransmitters levels, which had a positive impact on learning tasks. Cotreatment with melatonin resulted in an increase in the level of BDNF, marking ameliorated synaptic anomalies and learning disabilities, while reducing weight gain. On the other hand, the combination of melatonin and histidine reinstated the synaptic plasticity as well as brain barrier junctions, as demonstrated by increased levels of BDNF and ZO-1, positively affecting weight loss and the intellectual function.

The Influence of Sensory Characteristics of Game Meat on Consumer Neuroperception: A Narrative Review

Game meat contains bioactive compounds that directly influence the formation of a rich reservoir of flavor precursors that produce specific sensory properties. Quality is considered one of the most influential determinants of consumer behavior, but the interpretation of this concept differs between consumers. Although recognized for its quality, its unique sensory characteristics (smell, taste, aroma) may have a major impact on consumer perception. The aim of this review is to describe the consumer behavior regarding game meat through elements of neuroperception, using methods of analysis, observation, and interpretation of scientific information from the literature. Following the analysis of published papers on this topic, it was shown that external factors influencing the biological basis of behavior could provide explanations for the acceptance or rejection of this type of meat and solutions. Neuroperception can explain the mechanism behind consumer decision-making. The influence of extrinsic factors (environment, mood, emotions, stress) shapes the perception of the quality attributes of game meat, the unique sensory characteristics of game meat passing through a primary filter of sensory receptors (eyes, nose, tongue, etc). Game meat is darker and tougher (compared to meat from domestic animals), and the taste and smell have the power to trigger memories and change the mood, influencing consumer behavior. Understanding consumer attitudes towards game meat in relation to quality attributes and the physiology of sensory perception can provide important insights for food industry professionals, processors, sensory evaluators, and researchers.

Concentrations of Plasma Amino Acids and Neurotransmitters in Participants with Functional Gut Disorders and Healthy Controls

Amino acids are important in several biochemical pathways as precursors to neurotransmitters which impact biological processes previously linked to functional gastrointestinal disorders (FGIDs). Dietary protein consumption, metabolic host processes, and the gut microbiome can influence the plasma concentration of amino acids and neurotransmitters, and their uptake by tissues. The aim of this analysis was to quantify 19 proteogenic and 4 non-proteogenic amino acids and 19 neurotransmitters (including precursors and catabolites, herein referred to as neurotransmitters) to ascertain if their circulating concentrations differed between healthy participants and those with FGIDs. Plasma proteogenic and non-proteogenic amino acids and neurotransmitters were measured using ultra-performance liquid chromatography and liquid chromatography-mass spectrometry, respectively, from 165 participants (Rome IV: irritable bowel syndrome (IBS-constipation, IBS-diarrhea), functional constipation, functional diarrhea, and healthy controls). There were significant differences (p < 0.05) in pairwise comparisons between healthy controls and specific FGID groups for branched-chain amino acids (BCAAs), ornithine, and alpha-aminobutyric acid. No other significant differences were observed for the neurotransmitters or any other amino acids analyzed. Multivariate and bivariate correlation analyses between proteogenic and non-proteogenic amino acids and neurotransmitters for constipation (constipation (IBS-C and functional constipation) and phenotypes diarrhea (IBS-D and functional diarrhea)) and healthy controls suggested that associations between BCAAs, 5-hydroxytryptophan, and kynurenine in combination with tyrosine, 3,4-dihydroxyphenylalanine, and 3,4-dihydroxyphenylacetic acid and associations with gamma-aminobutyric acid, glutamate, asparagine, and serine are likely disrupted in FGID phenotypes. In conclusion, although correlations were evident between some proteogenic and non-proteogenic amino acids and neurotransmitters, the results showed minor concentration differences in plasma proteogenic and non-proteogenic amino acids, amino acid-derived metabolites, and neurotransmitters between FGID phenotypes and healthy controls.

On-chip microfluidic dual detection of amino acid metabolism disorders using cell-free protein synthesis

Various metabolic diseases are associated with the accumulation of specific amino acids due to abnormal metabolic pathways, and thus can be diagnosed by measuring the level of amino acids in body fluids. However, present methods for amino acid analysis are not readily accessible because they require a complex experimental setup, expensive equipment, and a long processing time. Here, we present a dual sensing microfluidic device that enables fast, portable, and quantitative analysis of target amino acids, harnessing the biological mechanism of protein synthesis. In this device, the working principle of a finger-actuated pumping unit is applied, and the microchannels are designed to perform cell-free synthesis of a reporter protein in response to the target amino acids in the assay samples. Multiple steps required for the translational assay are controlled by the simple operation of two pushbuttons on the device. It is demonstrated that the developed microfluidic device provides precise quantification of two amino acids (methionine and phenylalanine) within 30 min at room temperature. We expect that the application of the presented device can be readily extended to the point-of-care testing of other metabolic compounds.

Is It Time to Reconsider the U.S. Recommendations for Dietary Protein and Amino Acid Intake?

Since the U.S. Institute of Medicine's recommendations on protein and amino acid intake in 2005, new information supports the need to re-evaluate these recommendations. New lines of evidence include: (1) re-analysis/re-interpretation of nitrogen balance data; (2) results from indicator amino acid oxidation studies; (3) studies of positive functional outcomes associated with protein intakes higher than recommended; (4) dietary guidance and protein recommendations from some professional nutrition societies; and (5) recognition that the synthesis of certain dispensable amino acids may be insufficient to meet physiological requirements more often than previously understood. The empirical estimates, theoretical calculations and clinical functional outcomes converge on a similar theme, that recommendations for intake of protein and some amino acids may be too low in several populations, including for older adults (≥65 years), pregnant and lactating women, and healthy children older than 3 years. Additional influential factors that should be considered are protein quality that meets operational sufficiency (adequate intake to support healthy functional outcomes), interactions between protein and energy intake, and functional roles of amino acids which could impact the pool of available amino acids for use in protein synthesis. Going forward, the definition of "adequacy" as it pertains to protein and amino acid intake recommendations must take into consideration these critical factors.

Genetically encoded fluorescent sensors for imaging neuronal dynamics in vivo

The brain relies on many forms of dynamic activities in individual neurons, from synaptic transmission to electrical activity and intracellular signaling events. Monitoring these neuronal activities with high spatiotemporal resolution in the context of animal behavior is a necessary step to achieve a mechanistic understanding of brain function. With the rapid development and dissemination of highly optimized genetically encoded fluorescent sensors, a growing number of brain activities can now be visualized in vivo. To date, cellular calcium imaging, which has been largely used as a proxy for electrical activity, has become a mainstay in systems neuroscience. While challenges remain, voltage imaging of neural populations is now possible. In addition, it is becoming increasingly practical to image over half a dozen neurotransmitters, as well as certain intracellular signaling and metabolic activities. These new capabilities enable neuroscientists to test previously unattainable hypotheses and questions. This review summarizes recent progress in the development and delivery of genetically encoded fluorescent sensors, and highlights example applications in the context of in vivo imaging.

A novel screening method for free non-standard amino acids in human plasma samples using AccQ·Tag reagents and LC-MS/MS

There are at least 500 naturally occurring amino acids, of which only 20 standard proteinogenic amino acids are used universally across all organisms in the synthesis of peptides and proteins. Non-standard amino acids can be incorporated into proteins or are intermediates and products of metabolic pathways. While the analysis of standard amino acids is well-defined, the analysis of non-standard amino acids can be challenging due to the wide range of physicochemical properties, and the lack of both reference standards and information in curated databases to aid compound identification. It has been shown that the use of an AccQ·Tag™ derivatization kit along with LC-MS/MS is an attractive option for the analysis of free standard amino acids in complex samples because it is fast, sensitive, reproducible, and selective. It has been demonstrated that the most abundant quantitative transition for MS/MS analysis of 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC) derivatized amino acids corresponds to the fragmentation of the molecule at the 6-aminoquinoline carbonyl group producing a common m/z 171 fragment ion and occurs at similar mass spectrometry collision energy and cone voltages. In this study, the unique properties of AQC derivatized amino acids producing high intensity common fragment ions, along with chromatographic separation of amino acids under generic chromatography conditions, were used to develop a novel screening method for the detection of trace levels of non-standard amino acids in complex matrices. Structural elucidation was carried out by comparing the MS/MS fragment ion mass spectra generated with in silico predicted fragmentation spectra to enable a putative identification, which was confirmed using an appropriate analytical standard. This workflow was applied to screen human plasma samples for bioactive thiol-group modified cysteine amino acids and S-allylmercaptocysteine (SAMC), S-allylcysteine sulfoxide (SACS or alliin) and S-propenylcysteine (S1PC) are reported for the first time to be present in human plasma samples after the administration of garlic supplements.

Acute Benefits of Acidified Milk Drinks with 10-g and 15-g Protein on Shifting and Updating Performances in Young Adults: A Randomized Controlled Trial

BACKGROUND

Accumulating evidence has shown that protein-rich milk drinks can rapidly improve cognitive performance. However, the optimum doses of milk protein that are needed to improve cognitive function remain to be investigated.

OBJECTIVE

This study aimed to determine whether acidified milk drinks with 10-g and 15-g milk protein have acute benefits on key cognitive functions in healthy young adults.

DESIGN

In this double-blinded randomized control trial, 66 young adults were randomly assigned to one of three groups (0-g, 10-g, and 15-g milk protein groups). Key cognitive functions (processing speed, inhibition, shifting, updating, and working memory capacity) were assessed before and 15 and 60 min after the drink intake.

RESULTS

We found that the shifting performance improved at 15 min after intake of the acidified 10-g and 15-g milk protein drinks compared to intake of the 0-g milk protein drink, and this acute effect of the acidified 15-g milk protein drink lasted for 60 min. In addition, updating performance improved at 60 min after intake of the acidified 10-g and 15-g milk protein drinks compared to intake of the 0-g milk protein drink.

CONCLUSION

Our findings suggest that the acidified 10-g and 15-g milk protein drinks have an acute benefit on shifting and updating performance in healthy young adults.

Advanced theragnostics for the central nervous system (CNS) and neurological disorders using functional inorganic nanomaterials

Various types of inorganic nanomaterials are capable of diagnostic biomarker detection and the therapeutic delivery of a disease or inflammatory modulating agent. Those multi-functional nanomaterials have been utilized to treat neurodegenerative diseases and central nervous system (CNS) injuries in an effective and personalized manner. Even though many nanomaterials can deliver a payload and detect a biomarker of interest, only a few studies have yet to fully utilize this combined strategy to its full potential. Combining a nanomaterial's ability to facilitate targeted delivery, promote cellular proliferation and differentiation, and carry a large amount of material with various sensing approaches makes it possible to diagnose a patient selectively and sensitively while offering preventative measures or early disease-modifying strategies. By tuning the properties of an inorganic nanomaterial, the dimensionality, hydrophilicity, size, charge, shape, surface chemistry, and many other chemical and physical parameters, different types of cells in the central nervous system can be monitored, modulated, or further studies to elucidate underlying disease mechanisms. Scientists and clinicians have better understood the underlying processes of pathologies for many neurologically related diseases and injuries by implementing multi-dimensional 0D, 1D, and 2D theragnostic nanomaterials. The incorporation of nanomaterials has allowed scientists to better understand how to detect and treat these conditions at an early stage. To this end, having the multi-modal ability to both sense and treat ailments of the central nervous system can lead to favorable outcomes for patients suffering from such injuries and diseases.

Chemotherapy-Induced Peripheral Neuropathy

Chemotherapy-induced peripheral neuropathy (CIPN) is a debilitating side effect of many common anti-cancer agents that can lead to dose reduction or treatment discontinuation, which decrease chemotherapy efficacy. Long-term CIPN can interfere with activities of daily living and diminish the quality of life. The mechanism of CIPN is not yet fully understood, and biomarkers are needed to identify patients at high risk and potential treatment targets. Metabolomics can capture the complex behavioral and pathophysiological processes involved in CIPN. This chapter is to review the CIPN metabolomics studies to find metabolic pathways potentially involved in CIPN. These potential CIPN metabolites are then investigated to determine whether there is evidence from studies of other neuropathy etiologies such as diabetic neuropathy and Leber hereditary optic neuropathy to support the importance of these pathways in peripheral neuropathy. Six potential biomarkers and their putative mechanisms in peripheral neuropathy were reviewed. Among these biomarkers, histidine and phenylalanine have clear roles in neurotransmission or neuroinflammation in peripheral neuropathy. Further research is needed to discover and validate CIPN metabolomics biomarkers in large clinical studies.

Plasma Amino Acid Concentrations in Children With Severe Malaria Are Associated With Mortality and Worse Long-term Kidney and Cognitive Outcomes

BACKGROUND

Global changes in amino acid levels have been described in severe malaria (SM), but the relationship between amino acids and long-term outcomes in SM has not been evaluated.

METHODS

We measured enrollment plasma concentrations of 20 amino acids using high-performance liquid chromatography in 500 Ugandan children aged 18 months to 12 years, including 122 community children and 378 children with SM. The Kidney Disease: Improving Global Outcomes criteria were used to define acute kidney injury (AKI) at enrollment and chronic kidney disease (CKD) at 1-year follow-up. Cognition was assessed over 2 years of follow-up.

RESULTS

Compared to laboratory-defined, age-specific reference ranges, there were deficiencies in sulfur-containing amino acids (methionine, cysteine) in both community children and children with SM. Among children with SM, global changes in amino acid concentrations were observed in the context of metabolic complications including acidosis and AKI. Increases in threonine, leucine, and valine were associated with in-hospital mortality, while increases in methionine, tyrosine, lysine, and phenylalanine were associated with postdischarge mortality and CKD. Increases in glycine and asparagine were associated with worse attention in children <5 years of age.

CONCLUSIONS

Among children with SM, unique amino acid profiles are associated with mortality, CKD, and worse attention.