Nano-medicine therapy reprogramming metabolic network of tumour microenvironment: new opportunity for cancer therapies

Metabolic heterogeneity is one of the characteristics of tumour cells. In order to adapt to the tumour microenvironment of hypoxia, acidity and nutritional deficiency, tumour cells have undergone extensive metabolic reprogramming. Metabolites involved in tumour cell metabolism are also very different from normal cells, such as a large number of lactate and adenosine. Metabolites play an important role in regulating the whole tumour microenvironment. Taking metabolites as the target, it aims to change the metabolic pattern of tumour cells again, destroy the energy balance it maintains, activate the immune system, and finally kill tumour cells. In this paper, the regulatory effects of metabolites such as lactate, glutamine, arginine, tryptophan, fatty acids and adenosine were reviewed, and the related targeting strategies of nano-medicines were summarised, and the future therapeutic strategies of nano-drugs were discussed. The abnormality of tumour metabolites caused by tumour metabolic remodelling not only changes the energy and material supply of tumour, but also participates in the regulation of tumour-related signal pathways, which plays an important role in the survival, proliferation, invasion and metastasis of tumour cells. Regulating the availability of local metabolites is a new aspect that affects tumour progress. (The graphical abstract is by Figdraw).

Circular RNAs Mediate the Effects of Dietary Tryptophan on the Transformation of Muscle Fiber Types in Weaned Piglets

The nutritional composition of the diet significantly impacts the overall growth and development of weaned piglets. The current study aimed to explore the effects and underlying mechanisms of dietary tryptophan consumption on muscle fiber type transformation during the weaning period. Thirty weaned piglets with an average body weight of 6.12 ± 0.16 kg were randomly divided into control (CON, 0.14% Trp diet) and high Trp (HT, 0.35% Trp) groups and maintained on the respective diet for 28 days. The HT group of weaned piglets exhibited highly significant improvements in growth performance and an increased proportion of fast muscle fibers. Transcriptome sequencing revealed the potential contribution of differentially expressed circular RNAs toward the transformation of myofiber types in piglets and toward the regulation of expression of related genes by targeting the microRNAs, miR-34c and miR-182, to further regulate myofiber transformation. In addition, 145 DE circRNAs were identified as potentially protein-encoding, with the encoded proteins associated with a myofiber type transformation. In conclusion, the current study greatly advances and refines our current understanding of the regulatory networks associated with piglet muscle development and myofiber type transformation and also contributes to the optimization of piglet diet formulation.

Indole Propionic Acid Disturbs the Normal Function of Tryptophanyl-tRNA Synthetase in Mycobacterium tuberculosis

Tuberculosis (TB) is the leading infectious disease caused by Mycobacterium tuberculosis and the second-most contagious killer after COVID-19. The emergence of drug-resistant TB has caused a great need to identify and develop new anti-TB drugs with novel targets. Indole propionic acid (IPA), a structural analog of tryptophan (Trp), is active against M. tuberculosis in vitro and in vivo. It has been verified that IPA exerts its antimicrobial effect by mimicking Trp as an allosteric inhibitor of TrpE, which is the first enzyme in the Trp synthesis pathway of M. tuberculosis. However, other Trp structural analogs, such as indolmycin, also target tryptophanyl-tRNA synthetase (TrpRS), which has two functions in bacteria: synthesis of tryptophanyl-AMP by catalyzing ATP + Trp and producing Trp-tRNATrp by transferring Trp to tRNATrp. So, we speculate that IPA may also target TrpRS. In this study, we found that IPA can dock into the Trp binding pocket of M. tuberculosis TrpRS (TrpRSMtb), which was further confirmed by isothermal titration calorimetry (ITC) assay. The biochemical analysis proved that TrpRS can catalyze the reaction between IPA and ATP to generate pyrophosphate (PPi) without Trp as a substrate. Overexpression of wild-type trpS in M. tuberculosis increased the MIC of IPA to 32-fold, and knock-down trpS in Mycolicibacterium smegmatis made it more sensitive to IPA. The supplementation of Trp in the medium abrogated the inhibition of M. tuberculosis by IPA. We demonstrated that IPA can interfere with the function of TrpRS by mimicking Trp, thereby impeding protein synthesis and exerting its anti-TB effect.

High-Resolution Plasma Metabolomics Identifies Alterations in Fatty Acid, Energy, and Micronutrient Metabolism in Adults Across the Leprosy Spectrum

BACKGROUND

High-resolution metabolomics (HRM) is an innovative tool to study challenging infectious diseases like leprosy, where the pathogen cannot be grown with standard methods. Here, we use HRM to better understand associations between disease manifestations, nutrition, and host metabolism.

METHODS

From 2018 to 2019, adults with leprosy and controls were recruited in Minas Gerais, Brazil. Plasma metabolites were detected using an established HRM workflow and characterized by accurate mass, mass to charge ratio m/z and retention time. The mummichog informatics package compared metabolic pathways between cases and controls and between multibacillary (MB) and paucibacillary (PB) leprosy. Additionally, select individual metabolites were quantified and compared.

RESULTS

Thirty-nine cases (62% MB and 38% PB) and 25 controls were enrolled. We found differences (P < .05) in several metabolic pathways, including fatty acid metabolism, carnitine shuttle, retinol, vitamin D3, and C-21 steroid metabolism, between cases and controls with lower retinol and associated metabolites in cases. Between MB and PB, leukotrienes, prostaglandins, tryptophan, and cortisol were all found to be lower in MB (P < .05).

DISCUSSION

Metabolites associated with several nutrient-related metabolic pathways appeared differentially regulated in leprosy, especially MB versus PB. This pilot study demonstrates the metabolic interdependency of these pathways, which may play a role in the pathophysiology of disease.

Infant microbes and metabolites point to childhood neurodevelopmental disorders

This study has followed a birth cohort for over 20 years to find factors associated with neurodevelopmental disorder (ND) diagnosis. Detailed, early-life longitudinal questionnaires captured infection and antibiotic events, stress, prenatal factors, family history, and more. Biomarkers including cord serum metabolome and lipidome, human leukocyte antigen (HLA) genotype, infant microbiota, and stool metabolome were assessed. Among the 16,440 Swedish children followed across time, 1,197 developed an ND. Significant associations emerged for future ND diagnosis in general and for specific ND subtypes, spanning intellectual disability, speech disorder, attention-deficit/hyperactivity disorder, and autism. This investigation revealed microbiome connections to future diagnosis as well as early emerging mood and gastrointestinal problems. The findings suggest links to immunodysregulation and metabolism, compounded by stress, early-life infection, and antibiotics. The convergence of infant biomarkers and risk factors in this prospective, longitudinal study on a large-scale population establishes a foundation for early-life prediction and intervention in neurodevelopment.

Oral tryptophan activates duodenal aryl hydrocarbon receptor in healthy subjects: a crossover randomized controlled trial

Background and Aims: Tryptophan is an essential amino acid transformed by host and gut microbial enzymes into metabolites that regulate mucosal homeostasis through Aryl hydrocarbon receptor (AhR) activation. Alteration of tryptophan metabolism has been associated with chronic inflammation, however whether tryptophan supplementation affects the metabolite repertoire and AhR activation under physiologic conditions in humans, is unknown. Methods: We performed a randomized, double blind, placebo-controlled, crossover study in 20 healthy volunteers. Subjects on a low tryptophan background diet were randomly assigned to a 3-week L-tryptophan supplementation (3 g/day) or placebo, and after a 2-week washout switched to opposite interventions. We assessed gastrointestinal and psychological symptoms by validated questionnaires, AhR activation by cell reporter assay, tryptophan metabolites by liquid chromatography and high-resolution mass spectrometry, cytokine production in isolated monocytes by ELISA and microbiota profile by 16S rRNA Illumina technique. Results: Oral tryptophan supplementation was well tolerated, with no changes in gastrointestinal or psychological scores. Compared with placebo, tryptophan increased AhR activation capacity by duodenal contents, but not by feces. This was paralleled by higher urinary and plasma kynurenine metabolites and indoles. Tryptophan had a modest impact on fecal microbiome profiles, and no significant effect on cytokine production. Conclusions: At the doses used in this study, oral tryptophan supplementation in humans induces microbial indole and host kynurenine metabolic pathways in the small intestine, known to be immunomodulatory. The results should prompt tryptophan intervention strategies in inflammatory conditions of the small intestine where the AhR pathway is impaired.

Recent Advances in Current Uptake Situation, Metabolic and Nutritional Characteristics, Health, and Safety of Dietary Tryptophan

Tryptophan (Trp) is an essential amino acid which is unable to be synthesized in the body. Main sources of Trp are uptake of foods such as oats and bananas. In this review, we describe the status of current dietary consumption, metabolic pathways and nutritional characteristics of Trp, as well as its ingestion and downstream metabolites for maintaining body health and safety. This review also summarizes the recent advances in Trp metabolism, particularly the 5-HT, KYN, and AhR activation pathways, revealing that its endogenous host metabolites are not only differentially affected in the body but also are closely linked to health. More attention should be paid to targeting its specific metabolic pathways and utilizing food molecules and probiotics for manipulating Trp metabolism. However, the complexity of microbiota-host interactions requires further exploration to precisely refine targets for innovating the gut microbiota-targeted diagnostic approaches and informing subsequent studies and targeted treatments of diseases.

Metabolomic and Transcriptomic Correlative Analyses in Germ-Free Mice Link Lacticaseibacillus rhamnosus GG-Associated Metabolites to Host Intestinal Fatty Acid Metabolism and β-Oxidation

Intestinal microbiota confers susceptibility to diet-induced obesity, yet many probiotic species that synthesize tryptophan (trp) actually attenuate this effect, although the underlying mechanisms are unclear. We monocolonized germ-free mice with a widely consumed probiotic Lacticaseibacillus rhamnosus GG (LGG) under trp-free or -sufficient dietary conditions. We obtained untargeted metabolomics from the mouse feces and serum using liquid chromatography-mass spectrometry and obtained intestinal transcriptomic profiles via bulk-RNA sequencing. When comparing LGG-monocolonized mice with germ-free mice, we found a synergy between LGG and dietary trp in markedly promoting the transcriptome of fatty acid metabolism and β-oxidation. Upregulation was specific and was not observed in transcriptomes of trp-fed conventional mice and mice monocolonized with Ruminococcus gnavus. Metabolomics showed that fecal and serum metabolites were also modified by LGG-host-trp interaction. We developed an R-Script-based MEtabolome-TRanscriptome Correlation Analysis algorithm and uncovered LGG- and trp-dependent metabolites that were positively or negatively correlated with fatty acid metabolism and β-oxidation gene networks. This high-throughput metabolome-transcriptome correlation strategy can be used in similar investigations to reveal potential interactions between specific metabolites and functional or disease-related transcriptomic networks.

Dietary tryptophan alleviates intestinal inflammation caused by long photoperiod via gut microbiota derived tryptophan metabolites-NLRP3 pathway in broiler chickens

Light pollution is a potential risk factor for intestinal health. Tryptophan plays an important role in the inhibition of intestinal inflammation. However, the mechanism of tryptophan in alleviating intestinal inflammation caused by long photoperiod is still unclear. This study investigated the anti-inflammatory effect of dietary tryptophan on intestinal inflammatory damage induced by long photoperiod and its potential mechanism in broiler chickens. We found that dietary tryptophan mitigated long photoperiod-induced intestinal tissue inflammatory damage and inhibited the activation of Nucleotide-Binding Oligomerization Domain, Leucine-Rich Repeat and Pyrin Domain-Containing 3 inflammasome. Moreover, dietary tryptophan significantly increased the relative abundance of Faecalibacterium, Enterococcus, and Lachnospiraceae_NC2004_group were significantly decreased the relative abundance of Ruminococcus_torques_group and norank_f_UCG-010 under the condition of long photoperiod (P < 0.05). The results of tryptophan targeted metabolomics show that tryptophan significantly increased indole-3-acetic acid (IAA) and indole-3 lactic acid (ILA), and significantly decreased xanthurenic acid (XA) under long photoperiod (P < 0.05). In conclusion, the results indicated that dietary tryptophan alleviates intestinal inflammatory damage caused by long photoperiod via the inhibition of Nucleotide-Binding Oligomerization Domain, Leucine-Rich Repeat and Pyrin Domain-Containing 3 inflammasome activation, which was mediated by tryptophan metabolites. Therefore, tryptophan supplementation could be a promising way to protect the intestine health under the condition of long photoperiod.

Dual treatment with kynurenine pathway inhibitors and NAD+ precursors synergistically extends life span in Drosophila

Tryptophan catabolism is highly conserved and generates important bioactive metabolites, including kynurenines, and in some animals, NAD+. Aging and inflammation are associated with increased levels of kynurenine pathway (KP) metabolites and depleted NAD+, factors which are implicated as contributors to frailty and morbidity. Contrastingly, KP suppression and NAD+ supplementation are associated with increased life span in some animals. Here, we used DGRP_229 Drosophila to elucidate the effects of KP elevation, KP suppression, and NAD+ supplementation on physical performance and survivorship. Flies were chronically fed kynurenines, KP inhibitors, NAD+ precursors, or a combination of KP inhibitors with NAD+ precursors. Flies with elevated kynurenines had reduced climbing speed, endurance, and life span. Treatment with a combination of KP inhibitors and NAD+ precursors preserved physical function and synergistically increased maximum life span. We conclude that KP flux can regulate health span and life span in Drosophila and that targeting KP and NAD+ metabolism can synergistically increase life span.

Different Kynurenine Pathway Dysregulation in Systemic Sclerosis in Men and Women

Systemic sclerosis (SSc), a predominantly female-affected systemic autoimmune disease, requires tailored treatment strategies contingent on organ involvement and symptom severity. Given SSc's inflammatory nature, the involvement of the kynurenine pathway (KP) in its pathophysiology is underexplored. Our study aimed to investigate sex-related differences in KP activation among SSc patients and assess the impact of angiotensin-converting enzyme (ACE) inhibitors and estimated glomerular filtration rate (eGFR) on KP metabolite concentrations. We enrolled 48 SSc patients and 53 healthy controls, quantifying KP metabolites (tryptophan (TRP), kynurenine (KYN), and kynurenic acid (KYNA)) in serum via high-performance liquid chromatography. Separate multivariate analyses of covariance (MANCOVAs) for women and men were performed to ascertain mean differences between patients and healthy controls while correcting for age. For our secondary objective, we conducted a MANCOVA to explore disparities in ACE inhibitor users and non-users among patients, with BMI correction. Our findings revealed decreased TRP concentrations but increased KYNA/TRP ratio and KYN/TRP ratio in both male and female SSc patients compared to their respective controls. Unlike women, SSc males exhibited higher KYN concentrations and decreased KYNA/KYN ratio relative to their controls. Additionally, SSc patients using ACE inhibitors had higher serum KYNA levels than non-users. Notably, we established a significant correlation between eGFR and KYNA in SSc patients. These results indicate differential KP activation in male and female SSc patients, with males demonstrating heightened KP activation. While ACE inhibitors may influence the KP in SSc patients, further research is necessary to comprehensively understand their impact on symptoms and prognosis in the context of these KP alterations.

Is It Possible to Mitigate Fear of Fireworks in Dogs? A Study on the Behavioural and Physiological Effects of a Psychoactive Supplement

Canine fear of fireworks is a common problem worldwide, with serious implications for the welfare of both dogs and their owners. Therapies for the problem are available, and herbal and nutraceutical agents are increasingly suggested by professionals; nonetheless, studies on their real efficacy in reducing firework fear are lacking. In a randomised, double-blinded, placebo-controlled study, 44 dogs (25 in the "supplement" group and 19 in the "placebo" group) completed a long-term continuous treatment with either a supplement made of tryptophan, valerian, and passiflora or a placebo, including two real exposures to fireworks (on 2020 Christmas and 2021 New Years' Eve, after 42 and 48 days of treatment, respectively). Owners of both groups received the same general environmental management and food/toy offering recommendations for trying with their dogs on those nights. Behavioural (measured by LSSS-Lincoln Sound Sensitivity Scale and PANAS-Positive and Negative Activation scale, as rated by the owners) and stress (measured via salivary cortisol measures) reactions were evaluated. Significantly greater fear decrease (LSSS) was recorded in the "supplement" dogs, as compared to the "placebo" group. Cortisol dosages on New Year's Eve ("noisy" night) were in line with behavioural results; "supplement" dogs showed a smaller increase in the stress response from 22:30 to 00:30 h on New Year's Eve and a greater decrease in their stress response from 02:30 h to 10:30 h on New Year's Day compared to "placebo" dogs. Smaller cortisol levels were also shown by "supplement" dogs than "placebo" dogs on a controlled "quiet night" (27th December). Owners' rates on PANAS remained stable during the whole period of therapy for both groups. The evaluated supplement, a combination of tryptophan, valerian, and passiflora, showed satisfactory results and rare side effects when treating dogs fearful of fireworks.

Formation, Identification, and Occurrence of the Furan-Containing β-Carboline Flazin Derived from l-Tryptophan and Carbohydrates

β-Carbolines (βCs) are bioactive indole alkaloids found in foods and in vivo. This work describes the identification, formation, and occurrence in foods of the βC with a furan moiety flazin (1-[5-(hydroxymethyl)furan-2-yl]-9H-pyrido[3,4-b]indole-3-carboxylic acid). Flazin was formed by the reaction of l-tryptophan with 3-deoxyglucosone but not with 5-hydroxymethylfurfural. Its formation was favored in acidic conditions and heating (70-110 °C). The proposed mechanism of formation occurs through the formation of intermediates 3,4-dihydro-β-carboline-3-carboxylic acid (imines), followed by the oxidation to C═O in the carbohydrate chain and aromatization to βC ring with subsequent dehydration steps and cyclization to afford the furan moiety. Flazin is generated in the reactions of tryptophan with carbohydrates. Its formation from fructose was higher than from glucose, whereas sucrose gave flazin under acidic conditions and heating owing to hydrolysis. Flazin was identified in foods by HPLC-MS, and its content was determined by HPLC-fluorescence. It occurred in numerous processed foods, such as tomato products, including crushed tomato puree, fried tomato, ketchup, tomato juices, and jams, but also in soy sauce, beer, balsamic vinegar, fruit juices, dried fruits, fried onions, and honey. Their concentrations ranged from not detected to 22.3 μg/mL, with the highest mean levels found in tomato concentrate (13.9 μg/g) and soy sauce (9.4 μg/mL). Flazin was formed during the heating process, as shown in fresh tomato juice and crushed tomatoes. These results indicate that flazin is widely present in foods and is daily uptaken in the diet.

Tryptophan metabolism and small fibre neuropathy: a correlation study

Small nerve fibres located in the epidermis sense pain. Dysfunction of these fibres decreases the pain threshold known as small fibre neuropathy. Diabetes mellitus is accompanied by metabolic changes other than glucose, synergistically eliciting small fibre neuropathy. These findings suggest that various metabolic changes may be involved in small fibre neuropathy. Herein, we explored the correlation between pain sensation and changes in plasma metabolites in healthy Japanese subjects. The pain threshold evaluated from the intraepidermal electrical stimulation was used to quantify pain sensation in a total of 1021 individuals in the 2017 Iwaki Health Promotion Project. Participants with a pain threshold evaluated from the intraepidermal electrical stimulation index <0.20 mA were categorized into the pain threshold evaluated from the intraepidermal electrical stimulation index-low group (n = 751); otherwise, they were categorized into the pain threshold evaluated from the intraepidermal electrical stimulation index-high group (n = 270). Metabolome analysis of plasma was conducted using capillary electrophoresis time-of-flight mass spectrometry. The metabolite set enrichment analysis revealed that the metabolism of tryptophan was significantly correlated with the pain threshold evaluated from the intraepidermal electrical stimulation index in all participants (P < 0.05). The normalized level of tryptophan was significantly decreased in participants with a high pain threshold evaluated from the intraepidermal electrical stimulation index. In addition to univariate linear regression analyses, the correlation between tryptophan concentration and the pain threshold evaluated from the intraepidermal electrical stimulation index remained significant after adjustment for multiple factors (β = -0.07615, P < 0.05). These findings indicate that specific metabolic changes are involved in the deterioration of pain thresholds. Here, we show that abnormal tryptophan metabolism is significantly correlated with an elevated pain threshold evaluated from the intraepidermal electrical stimulation index in the Japanese population. This correlation provides insight into the pathology and clinical application of small fibre neuropathy.

Coupling and regulation mechanisms of the flavin-dependent halogenase PyrH observed by infrared difference spectroscopy

Flavin-dependent halogenases are central enzymes in the production of halogenated secondary metabolites in various organisms and they constitute highly promising biocatalysts for regioselective halogenation. The mechanism of these monooxygenases includes formation of hypohalous acid from a reaction of fully reduced flavin with oxygen and halide. The hypohalous acid then diffuses via a tunnel to the substrate-binding site for halogenation of tryptophan and other substrates. Oxidized flavin needs to be reduced for regeneration of the enzyme, which can be performed in vitro by a photoreduction with blue light. Here, we employed this photoreduction to study characteristic structural changes associated with the transition from oxidized to fully reduced flavin in PyrH from Streptomyces rugosporus as a model for tryptophan-5-halogenases. The effect of the presence of bromide and chloride or the absence of any halides on the UV-vis spectrum of the enzyme demonstrated a halide-dependent structure of the flavin-binding pocket. Light-induced FTIR difference spectroscopy was applied and the signals assigned by selective isotope labeling of the protein moiety. The identified structural changes in α-helix and β-sheet elements were strongly dependent on the presence of bromide, chloride, the substrate tryptophan, and the product 5-chloro-tryptophan, respectively. We identified a clear allosteric coupling in solution at ambient conditions between cofactor-binding site and substrate-binding site that is active in both directions, despite their separation by a tunnel. We suggest that this coupling constitutes a fine-tuned mechanism for the promotion of the enzymatic reaction of flavin-dependent halogenases in dependence of halide and substrate availability.

Microbiota, Tryptophan and Aryl Hydrocarbon Receptors as the Target Triad in Parkinson's Disease-A Narrative Review

In the era of a steadily increasing lifespan, neurodegenerative diseases among the elderly present a significant therapeutic and socio-economic challenge. A properly balanced diet and microbiome diversity have been receiving increasing attention as targets for therapeutic interventions in neurodegeneration. Microbiota may affect cognitive function, neuronal survival and death, and gut dysbiosis was identified in Parkinson's disease (PD). Tryptophan (Trp), an essential amino acid, is degraded by microbiota and hosts numerous compounds with immune- and neuromodulating properties. This broad narrative review presents data supporting the concept that microbiota, the Trp-kynurenine (KYN) pathway and aryl hydrocarbon receptors (AhRs) form a triad involved in PD. A disturbed gut-brain axis allows the bidirectional spread of pro-inflammatory molecules and α-synuclein, which may contribute to the development/progression of the disease. We suggest that the peripheral levels of kynurenines and AhR ligands are strongly linked to the Trp metabolism in the gut and should be studied together with the composition of the microbiota. Such an approach can clearly delineate the sub-populations of PD patients manifesting with a disturbed microbiota-Trp-KYN-brain triad, who would benefit from modifications in the Trp metabolism. Analyses of the microbiome, Trp-KYN pathway metabolites and AhR signaling may shed light on the mechanisms of intestinal distress and identify new targets for the diagnosis and treatment in early-stage PD. Therapeutic interventions based on the combination of a well-defined food regimen, Trp and probiotics seem of potential benefit and require further experimental and clinical research.

Dual-directional regulation of spinal cord injury and the gut microbiota

There is increasing evidence that the gut microbiota affects the incidence and progression of central nervous system diseases via the brain-gut axis. The spinal cord is a vital important part of the central nervous system; however, the underlying association between spinal cord injury and gut interactions remains unknown. Recent studies suggest that patients with spinal cord injury frequently experience intestinal dysfunction and gut dysbiosis. Alterations in the gut microbiota can cause disruption in the intestinal barrier and trigger neurogenic inflammatory responses which may impede recovery after spinal cord injury. This review summarizes existing clinical and basic research on the relationship between the gut microbiota and spinal cord injury. Our research identified three key points. First, the gut microbiota in patients with spinal cord injury presents a key characteristic and gut dysbiosis may profoundly influence multiple organs and systems in patients with spinal cord injury. Second, following spinal cord injury, weakened intestinal peristalsis, prolonged intestinal transport time, and immune dysfunction of the intestine caused by abnormal autonomic nerve function, as well as frequent antibiotic treatment, may induce gut dysbiosis. Third, the gut microbiota and associated metabolites may act on central neurons and affect recovery after spinal cord injury; cytokines and the Toll-like receptor ligand pathways have been identified as crucial mechanisms in the communication between the gut microbiota and central nervous system. Fecal microbiota transplantation, probiotics, dietary interventions, and other therapies have been shown to serve a neuroprotective role in spinal cord injury by modulating the gut microbiota. Therapies targeting the gut microbiota or associated metabolites are a promising approach to promote functional recovery and improve the complications of spinal cord injury.

Application of Tryptophan and Methionine in Broccoli Seedlings Enhances Formation of Anticancer Compounds Sulforaphane and Indole-3-Carbinol and Promotes Growth

Broccoli is a popular cruciferous vegetable that is well known for its abundant health-promoting biochemicals. The most important of these beneficial biochemicals are glucosinolates, including glucoraphanin and glucobrassicin. Glucoraphanin and glucobrassicin can be broken down by myrosinases into sulforaphane and indole-3-carbinol, which have been demonstrated to have potent cancer-preventive properties. Efforts to increase glucoraphanin in broccoli seedlings have long been a focus; however, increasing glucoraphanin and glucobrassicin simultaneously, as well as enhancing myrosinase activity to release more sulforaphane and indole-3-carbinol, have yet to be investigated. This study aims to investigate the impact of the combined application of tryptophan and methionine on the accumulation of sulforaphane and indole-3-carbinol, as well as their precursors. Furthermore, we also examined whether this application has any effects on seedling growth and the presence of other beneficial compounds. We found that the application of methionine and tryptophan not only increased the glucoraphanin content by 2.37 times and the glucobrassicin content by 3.01 times, but that it also caused a higher myrosinase activity, resulting in a1.99 times increase in sulforaphane and a 3.05 times increase in indole-3-carbinol. In addition, better plant growth and an increase in amino acids and flavonoids were observed in broccoli seedlings with this application. In conclusion, the simultaneous application of tryptophan and methionine to broccoli seedlings can effectively enhance their health-promoting value and growth. Our study provides a cost-effective and multi-benefit strategy for improving the health value and yield of broccoli seedlings, benefiting both consumers and farmers.

Evaluation of inflammatory biomarkers and vitamins in hospitalized patients with SARS-CoV-2 infection and post-COVID syndrome

OBJECTIVES

Concentrations of neopterin, kynurenine and kynurenine/tryptophan ratios predict prognosis and the need for oxygen therapy in patients hospitalized for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. The aims of the present study were to evaluate the changes of these biomarkers early in the course of infection, the association with the prior coronavirus disease (COVID-19) vaccination and therapeutic administration of Anti-SARS-CoV-2 monoclonal antibodies, investigation of other potential biomarkers including neuropilin, 8-hydroxy-2-deoxyguanosine and 8-hydroxyguanosine in patients hospitalized with SARS-CoV-2 infection and an assessment of these biomarkers and vitamins A, E and D in patients with post-COVID syndrome.

METHODS

Urine and blood samples were obtained on the 1st to the 4th day and 4th to 7th day from 108 patients hospitalized with COVID-19. Chromatography tandem mass spectrometry methods were used to analyse neopterin, kynurenine, tryptophan, liposoluble vitamins, and DNA damage biomarkers.

RESULTS

A statistically significant decrease of neopterin, kynurenine and kynurenine/tryptophan ratios was observed on after 4th to 7th day of hospitalization, and concentrations of these biomarkers were increased in patients with poor prognosis and subsequent post-COVID syndrome. The concentrations of remaining biomarker and vitamins were not associated with outcomes, although markedly decreased concentrations of vitamin A, E and D were noted.

CONCLUSIONS

The concentrations of neopterin, kynurenine and kynurenine/tryptophan ratios decrease during the course of infection SARS-CoV-2 and are associated with the post-COVID syndrome. No other prognostic biomarkers were identified.

Association of tryptophan pathway metabolites with mortality and effectiveness of nutritional support among patients at nutritional risk: secondary analysis of a randomized clinical trial

Tryptophan is an essential amino acid and is the precursor of many important metabolites and neurotransmitters. In malnutrition, the availability of tryptophan is reduced, potentially putting patients at increased risks. Herein, we investigated the prognostic implications of the tryptophan metabolism in a secondary analysis of the Effect of Early Nutritional Support on Frailty, Functional Outcomes, and Recovery of Malnourished Medical Inpatients Trial (EFFORT), a randomized, controlled trial comparing individualized nutritional support to usual care in patients at risk for malnutrition. Among 238 patients with available measurements, low plasma levels of metabolites were independently associated with 30-day mortality with adjusted hazard ratios (HR) of 1.77 [95% CI 1.05-2.99, p 0.034] for tryptophan, 3.49 [95% CI 1.81-6.74, p < 0.001] for kynurenine and 2.51 [95% CI 1.37-4.63, p 0.003] for serotonin. Nutritional support had more beneficial effects on mortality in patients with high tryptophan compared to patients with low tryptophan levels (adjusted HR 0.61 [95% CI 0.29-1.29] vs. HR 1.72 [95% CI 0.79-3.70], p for interaction 0.047). These results suggest that sufficient circulating levels of tryptophan might be a metabolic prerequisite for the beneficial effect of nutritional interventions in this highly vulnerable patient population.

The regulatory effects of (p)ppGpp and indole on cAMP synthesis in Escherichia coli cells

Bacterial stress adaptive response is formed due to changes in the cell gene expression profile in response to alterations in environmental conditions through the functioning of regulatory networks. The mutual influence of network signaling molecules represented by cells' natural metabolites, including indole and second messengers (p) ppGpp and cAMP, is hitherto not well understood, being the aim of this study. E. coli parent strain BW25141 ((p) ppGpp+) and deletion knockout BW25141ΔrelAΔspoT which is unable to synthesize (p)ppGpp ((p)ppGpp0) were cultivated in M9 medium supplemented with different glucose concentrations (5.6 and 22.2 mM) in the presence of tryptophan as a substrate for indole synthesis and in its absence. The glucose content was determined with the glucose oxidase method; the indole content, by means of HPLC; and the cAMP concentration, by ELISA. The onset of an increase in initially low intracellular cAMP content coincided with the depletion of glucose in the medium. Maximum cAMP accumulation in the cells was proportional to the concentration of initially added glucose. At the same time, the (p) ppGpp0 mutant showed a decrease in maximum cAMP levels compared to the (p)ppGpp+ parent, which was the most pronounced in the medium with 22.2 mM glucose. So, (p)ppGpp was able to positively regulate cAMP formation. The promoter of the tryptophanase operon responsible for indole biosynthesis is known to be under the positive control of catabolic repression. Therefore, in the cells of the (p)ppGpp+ strain grown in the tryptophan-free medium that were characterized by a low rate of spontaneous indole formation, its synthesis significantly increased in response to the rising cAMP level just after glucose depletion. However, this was not observed in the (p)ppGpp0 mutant cells with reduced cAMP accumulation. When tryptophan was added to the medium, both of these strains demonstrated high indole production, which was accompanied by a decrease in cAMP accumulation compared to the tryptophan-free control. Thus, under glucose depletion, (p)ppGpp can positively regulate the accumulation of both cAMP and indole, while the latter, in its turn, has a negative effect on cAMP formation.

Verification studies of tryptophan and kynurenine determination using HPLC and evaluation of the kynurenine pathway and neopterin levels in human colostrum samples

Colostrum, the first breast fluid produced by mammals after giving birth, is followed by breast milk, which serves as the sole source of nutrients for breastfed newborns and infants. Tryptophan, an essential amino acid, plays a crucial role in the development and maturation of the central nervous system in infants. Tryptophan is primarily degraded through the kynurenine pathway. Owing to its sensitivity to dietary intake, immune-mediated tryptophan degradation is assessed by the kynurenine-to-tryptophan ratio, with a focus on one of the rate-limiting enzymes in the pathway. This study involved the validation of the simultaneous determination of tryptophan and kynurenine using HPLC. The validated method was then used to detect levels of tryptophan and kynurenine, as well as to calculate the kynurenine-to-tryptophan ratio in colostrum samples. Simultaneously, these results were compared with colostrum neopterin levels measured using commercial enzyme-linked immunosorbent assay kits. The mean levels for tryptophan, kynurenine, and neopterin were 17.3 ± 62.4 μM, 0.45 ± 0.03 μM, and 28.9 ± 2.6 nM, respectively. This study is among the few that have evaluated these parameters in colostrum samples. Neopterin levels secreted by the mammary gland were found not to be correlated with tryptophan degradation, a process influenced by the mother's nutritional status.

Intestinal Translocation of Live Porphyromonas gingivalis Drives Insulin Resistance

Periodontitis has been emphasized as a risk factor of insulin resistance-related systemic diseases. Accumulating evidence has suggested a possible "oral-gut axis" linking oral infection and extraoral diseases, but it remains unclear whether periodontal pathogens can survive the barriers of the digestive tract and how they play their pathogenic roles. The present study established a periodontitis mouse model through oral ligature plus Porphyromonas gingivalis inoculation and demonstrated that periodontitis aggravated diet-induced obesity and insulin resistance, while also causing P. gingivalis enrichment in the intestine. Metabolic labeling strategy validated that P. gingivalis could translocate to the gastrointestinal tract in a viable state. Oral administration of living P. gingivalis elicited insulin resistance, while administration of pasteurized P. gingivalis had no such effect. Combination analysis of metagenome sequencing and nontargeted metabolomics suggested that the tryptophan metabolism pathway, specifically indole and its derivatives, was involved in the pathogenesis of insulin resistance caused by oral administration of living P. gingivalis. Moreover, liquid chromatography-high-resolution mass spectrometry analysis confirmed that the aryl hydrocarbon receptor (AhR) ligands, mainly indole acetic acid, tryptamine, and indole-3-aldehyde, were reduced in diet-induced obese mice with periodontitis, leading to inactivation of AhR signaling. Supplementation with Ficz (6-formylindolo (3,2-b) carbazole), an AhR agonist, alleviated periodontitis-associated insulin resistance, in which the restoration of gut barrier function might play an important role. Collectively, these findings reveal that the oral-gut translocation of viable P. gingivalis works as a fuel linking periodontitis and insulin resistance, in which reduction of AhR ligands and inactivation of AhR signaling are involved. This study provides novel insight into the role of the oral-gut axis in the pathogenesis of periodontitis-associated comorbidities.

Unique Patterns in Amino Acid Sequences of Aging-Related Proteins

Aging has strong genetic components and the list of genes that may regulate the aging process is collected in the GenAge database. There may be characteristic patterns in the amino acid sequences of aging-related proteins that distinguish them from other proteins and this information will lead to a better understanding of the aging process. To test this hypothesis, human protein sequences are extracted from the UniProt database and the relative frequency of every amino acid residue in aging-related proteins and the remaining proteins is calculated. The main observation is that the mean relative frequency of aspartic acid (D) is consistently higher, while the mean relative frequencies of tryptophan (W) and leucine (L) are consistently lower in aging-related proteins compared to the non-aging-related proteins for the human and four examined model organisms. It is also observed that the mean relative frequency of aspartic acid is higher, while the mean relative frequency of tryptophan is lower in pro-longevity proteins compared to anti-longevity proteins in model organisms. Finally, it is found that aging-related proteins tend to be longer than non-aging-related proteins. It is hoped that this analysis initiates further computational and experimental research to explore the underlying mechanisms of these findings.

Untargeted metabolomic profiling in children identifies novel pathways in asthma and atopy

BACKGROUND

Asthma and other atopic disorders can present with varying clinical phenotypes marked by differential metabolomic manifestations and enriched biological pathways.

OBJECTIVE

We sought to identify these unique metabolomic profiles in atopy and asthma.

METHODS

We analyzed baseline nonfasted plasma samples from a large multisite pediatric population of 470 children aged <13 years from 3 different sites in the United States and France. Atopy positivity (At+) was defined as skin prick test result of ≥3 mm and/or specific IgE ≥ 0.35 IU/mL and/or total IgE ≥ 173 IU/mL. Asthma positivity (As+) was based on physician diagnosis. The cohort was divided into 4 groups of varying combinations of asthma and atopy, and 6 pairwise analyses were conducted to best assess the differential metabolomic profiles between groups.

RESULTS

Two hundred ten children were classified as At-As-, 42 as At+As-, 74 as At-As+, and 144 as At+As+. Untargeted global metabolomic profiles were generated through ultra-high-performance liquid chromatography-tandem mass spectroscopy. We applied 2 independent machine learning classifiers and short-listed 362 metabolites as discriminant features. Our analysis showed the most diverse metabolomic profile in the At+As+/At-As- comparison, followed by the At-As+/At-As- comparison, indicating that asthma is the most discriminant condition associated with metabolomic changes. At+As+ metabolomic profiles were characterized by higher levels of bile acids, sphingolipids, and phospholipids, and lower levels of polyamine, tryptophan, and gamma-glutamyl amino acids.

CONCLUSION

The At+As+ phenotype displays a distinct metabolomic profile suggesting underlying mechanisms such as modulation of host-pathogen and gut microbiota interactions, epigenetic changes in T-cell differentiation, and lower antioxidant properties of the airway epithelium.

Hordeum vulgare CYP76M57 catalyzes C2 shortening of tryptophan side chain by C-N bond rearrangement in gramine biosynthesis

The indole alkaloid gramine, 3-(dimethylaminomethyl)indole, is a defensive specialized metabolite found in some barley cultivars. In its biosynthetic process, the tryptophan (Trp) side chain is shortened by two carbon atoms to produce 3-(aminomethyl)indole (AMI), which is then methylated by N-methyltransferase (HvNMT) to produce gramine. Although side chain shortening is one of the crucial scaffold formation steps of alkaloids originating from aromatic amino acids, the gene and enzyme involved in the Trp-AMI conversion reactions are unknown. In this study, through RNA-seq analysis, 35 transcripts were shown to correlate with gramine production; among them, an uncharacterized cytochrome P450 (CYP) gene, CYP76M57, and HvNMT were identified as candidate genes for gramine production. Transgenic Arabidopsis thaliana and rice overexpressing CYP and HvNMT accumulate AMI, N-methyl-AMI, and gramine. CYP76M57, heterologously expressed in Pichia pastoris, was able to act on Trp to produce AMI. Furthermore, the amino group nitrogen of Trp was retained during the CYP76M57-catalyzed reaction, indicating that the C2 shortening of Trp proceeds with an unprecedented biosynthetic process, the removal of the carboxyl group and Cα and the rearrangement of the nitrogen atom to Cβ . In some gramine-non-accumulating barley cultivars, arginine 104 in CYP76M57 is replaced by threonine, which abolished the catalytic activity of CYP76M57 to convert Trp into AMI. These results uncovered the missing committed enzyme of gramine biosynthesis in barley and contribute to the elucidation of the potential functions of CYPs in plants and undiscovered specialized pathways.

Exploring the interplay between running exercises, microbial diversity, and tryptophan metabolism along the microbiota-gut-brain axis

The emergent recognition of the gut-brain axis connection has shed light on the role of the microbiota in modulating the gut-brain axis's functions. Several microbial metabolites, such as serotonin, kynurenine, tryptamine, indole, and their derivatives originating from tryptophan metabolism have been implicated in influencing this axis. In our study, we aimed to investigate the impact of running exercises on microbial tryptophan metabolism using a mouse model. We conducted a multi-omics analysis to obtain a comprehensive insight into the changes in tryptophan metabolism along the microbiota-gut-brain axis induced by running exercises. The analyses integrated multiple components, such as tryptophan changes and metabolite levels in the gut, blood, hippocampus, and brainstem. Fecal microbiota analysis aimed to examine the composition and diversity of the gut microbiota, and taxon-function analysis explored the associations between specific microbial taxa and functional activities in tryptophan metabolism. Our findings revealed significant alterations in tryptophan metabolism across multiple sites, including the gut, blood, hippocampus, and brainstem. The outcomes indicate a shift in microbiota diversity and tryptophan metabolizing capabilities within the running group, linked to increased tryptophan transportation to the hippocampus and brainstem through circulation. Moreover, the symbiotic association between Romboutsia and A. muciniphila indicated their potential contribution to modifying the gut microenvironment and influencing tryptophan transport to the hippocampus and brainstem. These findings have potential applications for developing microbiota-based approaches in the context of exercise for neurological diseases, especially on mental health and overall well-being.

Tryptophan, an important link in regulating the complex network of skin immunology response in atopic dermatitis

Atopic dermatitis (AD) is a common chronic relapsing inflammatory skin disease, of which the pathogenesis is a complex interplay between genetics and environment. Although the exact mechanisms of the disease pathogenesis remain unclear, the immune dysregulation primarily involving the Th2 inflammatory pathway and accompanied with an imbalance of multiple immune cells is considered as one of the critical etiologies of AD. Tryptophan metabolism has long been firmly established as a key regulator of immune cells and then affect the occurrence and development of many immune and inflammatory diseases. But the relationship between tryptophan metabolism and the pathogenesis of AD has not been profoundly discussed throughout the literatures. Therefore, this review is conducted to discuss the relationship between tryptophan metabolism and the complex network of skin inflammatory response in AD, which is important to elucidate its complex pathophysiological mechanisms, and then lead to the development of new therapeutic strategies and drugs for the treatment of this frequently relapsing disease.

Regulatory mechanism of the six-method massage antipyretic process on lipopolysaccharide-induced fever in juvenile rabbits: A targeted metabolomics approach

Objective

To investigate the mechanism of the six-method massage antipyretic process (SMAP) and its influence on the body's metabolic state.

Methods

The random number table method was used to divide 24 New Zealand 2-month-old rabbits with qualified basal body temperature into a control group, model group and massage group (n = 8 per group). The model group and massage groups were injected with 0.5 μg/ml lipopolysaccharide (1 ml/kg) into the auricular vein, and the control group was injected with the same amount of normal saline at the same temperature. One hour after modelling, the massage group was given SMAP (opening Tianmen, pushing Kangong, rubbing Taiyang, rubbing Erhougaogu, clearing the Tianheshui and pushing the spine). The change of anal temperature 5 h after moulding was recorded to clarify the antipyretic effect.

Results

After modelling, the rectal temperature of the juvenile rabbits in the three groups increased. The rectal temperature of the model group was higher than that of the control group 5 h after modelling, and the rectal temperature of the massage group was lower than that of the model group (P < 0.05). The antipyretic mechanism is related to the regulation of the synthesis of phenylalanine, tyrosine and tryptophan, as well as the pentose phosphate pathway. Compared with the model group, the plasma interleukin (IL)-1, IL-6, interferon-gamma, toll-like receptor 4, nuclear factor κB, the mechanistic target of rapamycin complex 1, indoleamine 2,3-dioxygenase 1, aryl hydrocarbon receptor, liver aspartate transaminase (AST), alanine transaminase (ALT) and l-glutamate dehydrogenase (L-GLDH) expression in the massage group were significantly decreased (P < 0.05). Compared with the model group, the massage group had significantly reduced AST, ALT and L-GLDH expression in plasma (P < 0.05).

Conclusion

The mechanism of SMAP therapy is related to regulating the expression of peripheral inflammatory factors and metabolic pathways.

Tryptophan Seed Treatment Improves Morphological, Biochemical, and Photosynthetic Attributes of the Sunflower under Cadmium Stress

Tryptophan, as a signal molecule, mediates many biotic and environmental stress-induced physiological responses in plants. Therefore, an experiment was conducted to evaluate the effect of tryptophan seed treatment in response to cadmium stress (0, 0.15, and 0.25 mM) in sunflower plants. Different growth and biochemical parameters were determined to compare the efficiency of the treatment agent. The results showed that cadmium stress reduced the growth attributes, including root and shoot length, dry and fresh weight, rate of seed germination, and the number of leaves. Cadmium stress also significantly reduced the contents of chlorophyll a, b, and total chlorophyll, carotenoid contents, phenolics, flavonoids, anthocyanin, and ascorbic acid. Whereas cadmium stress (0.15 and 0.25 mM) enhanced the concentrations of malondialdehyde (45.24% and 53.06%), hydrogen peroxide (-11.07% and 5.86%), and soluble sugars (28.05% and 50.34%) compared to the control. Tryptophan treatment decreased the effect of Cd stress by minimizing lipid peroxidation. Seed treatment with tryptophan under cadmium stress improved the root (19.40%) and shoot length (38.14%), root (41.90%) and shoot fresh weight (13.58%), seed germination ability (13.79%), average leaf area (24.07%), chlorophyll b (51.35%), total chlorophyll (20.04%), carotenoids (43.37%), total phenolic (1.47%), flavonoids (19.02%), anthocyanin (26.57%), ascorbic acid (4%), and total soluble proteins (12.32%) compared with control conditions. Overall, the tryptophan seed treatment showed positive effects on sunflower plants' growth and stress tolerance, highlighting its potential as a sustainable approach to improve crop performance.

Association between altered tryptophan metabolism, plasma aryl hydrocarbon receptor agonists, and inflammatory Chagas disease

Introduction

Chagas disease causes a cardiac illness characterized by immunoinflammatory reactions leading to myocardial fibrosis and remodeling. The development of Chronic Chagas Cardiomyopathy (CCC) in some patients while others remain asymptomatic is not fully understood, but dysregulated inflammatory responses are implicated. The Aryl hydrocarbon receptor (AhR) plays a crucial role in regulating inflammation. Certain tryptophan (Trp) metabolites have been identified as AhR ligands with regulatory functions.

Methods results and discussion

We investigated AhR expression, agonist response, ligand production, and AhR-dependent responses, such as IDO activation and regulatory T (Treg) cells induction, in two T. cruzi-infected mouse strains (B6 and Balb/c) showing different polymorphisms in AhR. Furthermore, we assessed the metabolic profile of Trp catabolites and AhR agonistic activity levels in plasma samples from patients with chronic Chagas disease (CCD) and healthy donors (HD) using a luciferase reporter assay and liquid chromatography-mass spectrophotometry (LC-MS) analysis. T. cruzi-infected B6 mice showed impaired AhR-dependent responses compared to Balb/c mice, including reduced IDO activity, kynurenine levels, Treg cell induction, CYP1A1 up-regulation, and AhR expression following agonist activation. Additionally, B6 mice exhibited no detectable AhR agonist activity in plasma and displayed lower CYP1A1 up-regulation and AhR expression upon agonist activation. Similarly, CCC patients had decreased AhR agonistic activity in plasma compared to HD patients and exhibited dysregulation in Trp metabolic pathways, resulting in altered plasma metabolite profiles. Notably, patients with severe CCC specifically showed increased N-acetylserotonin levels in their plasma. The methods and findings presented here contribute to a better understanding of CCC development mechanisms and may identify potential specific biomarkers for T. cruzi infection and the severity of associated heart disease. These insights could be valuable in designing new therapeutic strategies. Ultimately, this research aims to establish the AhR agonistic activity and Trp metabolic profile in plasma as an innovative, non-invasive predictor of prognosis for chronic Chagas disease.

The Influence of Kynurenine Metabolites on Neurodegenerative Pathologies

As the kynurenine pathway's links to inflammation, the immune system, and neurological disorders became more apparent, it attracted more and more attention. It is the main pathway through which the liver breaks down Tryptophan and the initial step in the creation of nicotinamide adenine dinucleotide (NAD+) in mammals. Immune system activation and the buildup of potentially neurotoxic substances can result from the dysregulation or overactivation of this pathway. Therefore, it is not shocking that kynurenines have been linked to neurological conditions (Depression, Parkinson's, Alzheimer's, Huntington's Disease, Schizophrenia, and cognitive deficits) in relation to inflammation. Nevertheless, preclinical research has demonstrated that kynurenines are essential components of the behavioral analogs of depression and schizophrenia-like cognitive deficits in addition to mediators associated with neurological pathologies due to their neuromodulatory qualities. Neurodegenerative diseases have been extensively associated with neuroactive metabolites of the kynurenine pathway (KP) of tryptophan breakdown. In addition to being a necessary amino acid for protein synthesis, Tryptophan is also transformed into the important neurotransmitters tryptamine and serotonin in higher eukaryotes. In this article, a summary of the KP, its function in neurodegeneration, and the approaches being used currently to target the route therapeutically are discussed.

Identification of novel biomarkers for frailty diagnosis via serum amino acids metabolomic analysis using UPLC-MS/MS

PURPOSE

This study was aimed to analyze serum amino acid metabolite profiles in frailty patients, gain a better understanding of the metabolic mechanisms in frailty, and assess the diagnostic value of metabolomics-based biomarkers of frailty.

EXPERIMENTAL DESIGN

This study utilized the ultra-performance liquid chromatography tandem mass spectrometry to examine amino acids associated with frailty. Additionally, we employed multivariate statistical methods, metabolomic data analysis, receiver operating characteristic (ROC) curve analysis, and pathway enrichment analysis.

RESULTS

Among the assayed amino acid metabolites, we identified biomarkers for frailty. ROC curve analysis for frailty diagnosis based on the modified Fried's frailty index showed that the areas under ROC curve of tryptophan, phenylalanine, aspartic acid, and combination were 0.775, 0.679, 0.667, and 0.807, respectively. ROC curve analysis for frailty diagnosis based on Frail Scale showed that the areas under ROC curve of cystine, phenylalanine, and combination of amino acids (cystine, L-Glutamine, citrulline, tyrosine, kynurenine, phenylalanine, glutamin acid) were 0.834, 0.708, and 0.854 respectively.

CONCLUSION AND CLINICAL RELEVANCE

In this study, we explored the serum amino acid metabolite profiles in frailty patients. These present metabolic analyses may provide valuable information on the potential biomarkers and the possible pathogenic mechanisms of frailty.

CLINICAL SIGNIFICANCE

Frailty is a clinical syndrome, as a consequence it is challenging to identify at early course of the disease, even based on the existing frailty scales. Early diagnosis and appropriate patient management are the key to improve the survival and limit disabilities in frailty patients. Proven by the extensive laboratory and clinical studies on frailty, comprehensive analysis of metabolic levels in frail patients, identification of biomarkers and study of pathogenic pathways of metabolites contribute to the prediction and early diagnosis of frailty. In this study, we explored the serum amino acid metabolite profiles in frailty patients. These present metabolic analyses may provide valuable information on the potential biomarkers and the possible pathogenic mechanisms of frailty.

Lactobacillus rhamnosus ameliorates acne vulgaris in SD rats via changes in gut microbiota and associated tryptophan metabolism

Background

The depletion of beneficial bacteria in the gut has been found in patients with acne vulgaris, and in previous studies, the supplement of Lactobacillus rhamnosus led to the improvement of adult acne. Nevertheless, the potential mechanism of L. rhamnosus in the amelioration of acne vulgaris has not been elucidated yet.

Methods

To mimic the human intestinal environment, a pseudo-germ-free rat model was used, and then gut microbiota from healthy individuals and acne patients were transplanted into rats. The effects of L. rhamnosus and tryptophan (Trp) metabolites on a rat acne model were investigated by gavage. Then, 16S rRNA analysis and targeted measurement of metabolites were performed to discover the differences in gut microbiota and metabolites between groups. Finally, HaCaT cells pretreated with Cutibacterium acnes were employed to validate the effect and mechanism of Trp metabolites on acne.

Results

L. rhamnosus significantly improved acne-like symptoms in rats by suppressing the level of inflammatory cytokines such as IL-1β, IL-6, and TNF-α. L. rhamnosus induced an increase in the production of indole-3-acetic acid (IAA) and indole via targeted Trp metabolic analyses. Furthermore, L. rhamnosus promoted bacterial diversity and also enhanced the Firmicutes/Bacteroidota (F/B) ratio, which was positively related to both IAA and indole. Finally, the roles of IAA and indole in alleviating acne vulgaris were confirmed both in vitro and in vivo, which could be reversed by AhR inhibitors.

Conclusion

Our study demonstrated that L. rhamnosus could exert its therapeutic effects on acne vulgaris by modulating the gut microbiota and regulating associated Trp metabolites.

Chronic Ethanol Intake Impairs Niacin Nutritional Status in Mice

Niacin is involved in many biological reactions relating energy metabolism, redox reactions, DNA repair and longevity. Since niacin deficiency has been reported in alcoholic patients, and niacin coenzyme NAD is used as substrate to dehydrogenate ethanol in the liver, ethanol consumption can be a factor to impair niacin nutritional status. We have recently established the niacin insufficient model mice using kynurenine 3-monooxygenase knock out (KMO-/-) mice with niacin-limited diet, which lack the de novo NAD synthesis pathway from tryptophan. To evaluate the effects of chronic ethanol intake on niacin nutritional status, 4 wk old KMO-/- mice were fed 4 or 30 mg/kg nicotinic acid containing diets with or without 15% ethanol for 35 d. The mice fed 4 mg/kg nicotinic acid diet with ethanol showed lower body weight gain and niacin nutritional markers such as liver and blood NAD, and urine nicotinamide metabolites than the mice without ethanol. These animals did not show any difference in the NAD synthesis, NAD salvage and nicotinamide catabolic pathways. Chronic ethanol intake failed to affect any indices in the mice fed the 30 mg/kg nicotinic acid diet. When the diet was exchanged the 4 mg/kg for 30 mg/kg nicotinic acid diet to the mice showed chronic ethanol-induced growth retardation, their body weight rapidly increased. These results show that chronic ethanol intake impairs niacin nutritional status in the niacin insufficient mice, and enough niacin intake can prevent this impairment. Our findings also suggest that chronic ethanol intake increases niacin requirement by increase of NAD consumption.

Plasma serotonin precursors and metabolite are correlated with bone mineral density and bone turnover markers in patients with postmenopausal osteoporosis

BACKGROUND

Serotonin (5-HT) precursors regulate bone remodeling. This study aims to investigate the correlation of plasma 5-HT precursors and metabolite with bone mineral density (BMD) and bone turnover markers in postmenopausal osteoporosis (PMOP) patients.

METHODS

The age, body mass index (BMI), and years since menopause (YSM) were documented for 348 postmenopausal women in normal/osteopenia/osteoporosis (OP) groups, with lumbar spine and femoral neck BMD measured. Serum bone turnover markers (PINP/β-CTX) and plasma 5-HT, 5-HT precursors (Trp/5-HTP) and metabolite (5-HIAA) were measured by ELISA. OP patients were allocated to high/low expression groups following ROC analysis of 5-HT/Trp/5-HTP/5-HIAA. The relationship of plasma 5-HT/Trp/5-HTP/5-HIAA, BMD, and bone turnover markers with PMOP was analyzed using logistic regression analysis. The correlation of plasma 5-HT/Trp/5-HTP/5-HIAA with BMD and bone turnover markers was analyzed using Pearson's correlation analysis, followed by logistic regression analysis of the relationship between plasma 5-HT/Trp/5-HTP/5-HIAA and BMD, bone turnover markers and PMOP.

RESULTS

BMI, YSM, BMD and PINP, and β-CTX levels differed among groups. Levels of plasma 5-HT precursors/metabolite were increased in OP patients. Individuals with high 5-HT precursors/metabolite levels had low BMD and high PINP/β-CTX levels. The 5-HT precursors/metabolite negatively-correlated with BMD and positively-correlated with PINP/β-CTX. BMI, YSM, BMD, and PINP/β-CTX/Trp/5-HTP/5-HT related to PMOP and were independent risk factors for OP.

CONCLUSION

Plasma 5-HT precursors and metabolite negatively-correlate with BMD and positively-correlate with PINP/β-CTX in PMOP patients. Peripheral 5-HT precursors and metabolite level may be a new direction of treatment of PMOP and bone metabolism-related disorders.

A High-Tryptophan Diet Alleviated Cognitive Impairment and Neuroinflammation in APP/PS1 Mice through Activating Aryl Hydrocarbon Receptor via the Regulation of Gut Microbiota

SCOPE

Recent studies have highlighted the vital role of gut microbiota in the pathogenesis of Alzheimer's disease (AD). However, the effect of the regulation of gut microbiota by dietary components on AD remains unknown. Thus, the study explored that a high-tryptophan (Trp) diet alleviates cognitive impairment by regulating microbiota.

METHODS AND RESULTS

Male APP/PS1 mice are fed 0.5% Trp diet for 4 weeks, and then cognitive function, amyloid-β (Aβ) deposition, microglial activation, proinflammatory cytokines production, and gut microbiota are detected. Moreover, the level of aryl hydrocarbon receptor (AhR) and NF-κB pathway related protein are determined. The results show that high-Trp diet significantly alleviates cognitive impairment and Aβ deposits. Moreover, high-Trp diet significantly inhibits activation of microglia, decreases the level of cluster of differentiation 11b (CD11b), and restrains the activation markers of microglia, such as cyclooxygenase-2 (Cox-2), interleukin (IL)-1β, and IL-6. Notably, high-Trp diet significantly activates AhR, inhibits the phosphorylation of p65, and improves microbiota dysbiosis.

CONCLUSIONS

These findings demonstrated that high-Trp diet exerts anti-inflammatory effects via upregulating AhR and suppressing NF-κB pathway, and its mechanisms may be mediated by regulating gut microbiota, suggesting that Trp diet may be a potential strategy for AD intervention.

Photocrosslinked Co-Assembled Amino Acid Nanoparticles for Controlled Chemo/Photothermal Combined Anticancer Therapy

Nanostructures formed from the self-assembly of amino acids are promising materials in many fields, especially for biomedical applications. However, their low stability resulting from the weak noncovalent interactions between the amino acid building blocks limits their use. In this work, nanoparticles co-assembled by fluorenylmethoxycarbonyl (Fmoc)-protected tyrosine (Fmoc-Tyr-OH) and tryptophan (Fmoc-Trp-OH) are crosslinked by ultraviolet (UV) light irradiation. Two methods are investigated to induce the dimerization of tyrosine, irradiating at 254 nm or at 365 nm in the presence of riboflavin as a photo-initiator. For the crosslinking performed at 254 nm, both Fmoc-Tyr-OH and Fmoc-Trp-OH generate dimers. In contrast, only Fmoc-Tyr-OH participates in the riboflavin-mediated dimerization under irradiation at 365 nm. The participation of both amino acids in forming the dimers leads to more stable crosslinked nanoparticles, allowing also to perform further chemical modifications for cancer applications. The anticancer drug doxorubicin (Dox) is adsorbed onto the crosslinked nanoparticles, subsequently coated by a tannic acid-iron complex, endowing the nanoparticles with glutathione-responsiveness and photothermal properties, allowing to control the release of Dox. A remarkable anticancer efficiency is obtained in vitro and in vivo in tumor-bearing mice thanks to the combined chemo- and photothermal treatment.

The Effects of Ferulic Acid, Tryptophan, and L-Glutamine on the Cryopreservation of Mouse Spermatozoa

In this study, the effects of ferulic acid (0.1, 1, ve 10 mM), tryptophan (5, 25, ve 50 mM), and L-glutamine (10, 50, ve 100 mM) at different doses added to 18% raffinose + 3% skimmed milk powder sperm extender on the freezing of mouse spermatozoa in liquid nitrogen were investigated. The combination of 18% raffinose + 3% skimmed milk powder without additives was used as the control group. Frozen spermatozoa were thawed in a 37°C water bath for 30 seconds. After freeze-thawing, motility, dead spermatozoa ratio, plasma membrane integrity, abnormal acrosome ratio, motility endurance (for 4 hours), and cell apoptosis tests were performed in Human Tubal Fluid (HTF). Compared with the control group after freezing and thawing, the highest motility and plasma membrane integrity were obtained in the 10 mM L-glutamine group with 56.6% ± 2.11% and 77.8% ± 0.87%, respectively (p < 0.05). In addition, when compared to the control group, the lowest rate of dead spermatozoa and abnormal acrosome was found in the 10 mM L-glutamine group as 26.0% ± 1.46% and 6.3% ± 1.09%, respectively (p < 0.05). The highest motility values for spermatozoa endurance were determined in the 10 and 50 mM L-glutamine groups up to the 4th hour compared to the control group (p < 0.05). In the evaluation of apoptosis in semen samples, there was no significant difference between the control, 0.1 mM ferulic acid, and 10 mM L-glutamine groups (p > 0.05). As a result, it was determined that the addition of 10 mM L-glutamine to the spermatozoa extender increased the motility, viable spermatozoa, functional membrane integrity, intact acrosome ratios, or motility endurance after freeze-thawing and could be used successfully in the freezing extender of mouse spermatozoa.

Development of an efficient Agrobacterium-mediated transformation method and its application in tryptophan pathway modification in Catharanthus roseus

The biosynthetic pathway of Catharanthus roseus vinca alkaloids has a long research history, including not only identification of metabolic intermediates but also the mechanisms of inter-cellular transport and accumulation of biosynthesized components. Vinca alkaloids pathway begins with strictosidine, which is biosynthesized by condensing tryptamine from the tryptophan pathway and secologanin from the isoprenoid pathway. Therefore, increasing the supply of precursor tryptophan may enhance vinca alkaloid content or their metabolic intermediates. Many reports on the genetic modification of C. roseus use cultured cells or hairy roots, but few reports cover the production of transgenic plants. In this study, we first investigated a method for stably producing transgenic plants of C. roseus, then, using this technique, we modified the tryptophan metabolism system to produce transgenic plants with increased tryptophan content. Transformed plants were obtained by infecting cotyledons two weeks after sowing with Agrobacterium strain A13 containing a plant expression vector, then selecting with 1/2 B5 medium supplemented with 50 mg l-1 kanamycin and 20 mg l-1 meropenem. Sixty-eight regenerated plants were obtained from 4,200 cotyledons infected with Agrobacterium, after which genomic PCR analysis using NPTII-specific primers confirmed gene presence in 24 plants with a transformation rate of 0.6%. Furthermore, we performed transformation into C. roseus using an expression vector to join trpE8 and aroG4 genes, which are feedback-resistant mutant genes derived from Escherichia coli. The resulting transformed plants showed exactly the same morphology as the wild-type, albeit with a marked increase in tryptophan and alkaloids content, especially catharanthine in leaves.

Tryptophan Metabolism in Postmenopausal Women with Functional Constipation

Constipation belongs to conditions commonly reported by postmenopausal women, but the mechanism behind this association is not fully known. The aim of the present study was to determine the relationship between some metabolites of tryptophan (TRP) and the occurrence and severity of abdominal symptoms (Rome IV) in postmenopausal women with functional constipation (FC, n = 40) as compared with age-adjusted postmenopausal women without FC. All women controlled their TRP intake in their daily diet. Urinary levels of TRP and its metabolites, 5-hydroxyindoleacetic acid (5-HIAA), kynurenine (KYN), and 3-indoxyl sulfate (indican, 3-IS), were determined by liquid chromatography/tandem mass spectrometry. Dysbiosis was assessed by a hydrogen-methane breath test. Women with FC consumed less TRP and had a lower urinary level of 5-HIAA, but higher levels of KYN and 3-IS compared with controls. The severity of symptoms showed a negative correlation with the 5-HIAA level, and a positive correlation with the 3-IS level. In conclusion, changes in TRP metabolism may contribute to FC in postmenopausal women, and dysbiosis may underlie this contribution.

Developmental and Nutritional Dynamics of Malpighian Tubule Autofluorescence in the Asian Tiger Mosquito Aedes albopictus

Malpighian tubules (MTs) are arthropod excretory organs crucial for the osmoregulation, detoxification and excretion of xenobiotics and metabolic wastes, which include tryptophan degradation products along the kynurenine (KYN) pathway. Specifically, the toxic intermediate 3-hydroxy kynurenine (3-HK) is metabolized through transamination to xanthurenic acid or in the synthesis of ommochrome pigments. Early investigations in Drosophila larval fat bodies revealed an intracellular autofluorescence (AF) that depended on tryptophan administration. Subsequent observations documented AF changes in the MTs of Drosophila eye-color mutants genetically affecting the conversion of tryptophan to KYN or 3-HK and the intracellular availability of zinc ions. In the present study, the AF properties of the MTs in the Asian tiger mosquito, Aedes albopictus, were characterized in different stages of the insect's life cycle, tryptophan-administered larvae and blood-fed adult females. Confocal imaging and microspectroscopy showed AF changes in the distribution of intracellular, brilliant granules and in the emission spectral shape and amplitude between the proximal and distal segments of MTs across the different samples. The findings suggest AF can serve as a promising marker for investigating the functional status of MTs in response to metabolic alterations, contributing to the use of MTs as a potential research model in biomedicine.

Design, Synthesis and Gene Modulation Insights into Pigments Derived from Tryptophan-Betaxanthin, Which Act against Tumor Development in Caenorhabditis elegans

The use of betalains, which are nitrogenous plant pigments, by the food industry is widespread and reflects their safety after intake. The recent research showed outstanding results for L-tryptophan-betaxanthin, a phytochemical present in traditional Chinese medicine, as an antitumoral agent when the activity was evaluated in the animal model Caenorhabditis elegans. Thus, L-tryptophan-betaxanthin is now presented as a lead compound, from which eleven novel structurally related betaxanthins have been designed, biotechnologically produced, purified, and characterized. The antitumoral effect of the derived compounds was evaluated on the JK1466 tumoral strain of C. elegans. All the tested molecules significantly reduced the tumoral gonad sizes in a range between 31.4% and 43.0%. Among the novel compounds synthesized, tryptophan methyl ester-betaxanthin and tryptophan benzyl ester-betaxanthin, which are the first betalains to contain an ester group in their structures, caused tumor size reductions of 43.0% and 42.6%, respectively, after administration to the model animal. Since these were the two most effective molecules, their mechanism of action was investigated by microarray analysis. Differential gene expression analysis showed that tryptophan methyl ester-betaxanthin and tryptophan benzyl ester-betaxanthin were able to down-regulate the key genes of the mTOR pathway, such as daf-15 and rict-1.

Exploring the Interaction of Indole-3-Acetonitrile with Neuroblastoma Cells: Understanding the Connection with the Serotonin and Dopamine Pathways

Indole-3-acetonitrile, a compound produced by bacteria and plants as a defense and survival signal in response to attacks, has been recently discovered as a metabolite produced by human cancer cells. This discovery suggests a potential association between IAN and cancer progression in patients. Consequently, the aim of this work was to study the effects of IAN on a specific cancer cell line, SH-SY5Y, and elucidate its connection to the serotonin and dopamine pathways by examining the precursors of these neurotransmitters. To achieve this, a cellular viability assay was conducted, along with a morphological evaluation of the cells under both normal and stress conditions. Our results demonstrated that for the highest concentrations in our study, IAN was able to reduce the cellular viability of the cells. Furthermore, when IAN was combined with the amino acids that originate the neurotransmitters, it was possible to observe that in both combinations there was a decrease in the viability of the cells. Thus, IAN may in fact have some influence on both the serotonin and dopamine pathways since changes in cell viability were observed when it was added together with the amino acids. This preliminary study indicates the presence of an interaction between IAN and neuroblastoma cells that justifies further exploration and study.

Stability Studies of Kynurenine Pathway Metabolites in Blood Components Define Optimal Blood Processing Conditions

The kynurenine pathway (KP) is the main pathway of tryptophan (TRP) metabolism that generates energy for multiple cellular processes. The activity of this pathway has been shown to be dysregulated in multiple human diseases. The resultant modulation of metabolites has been suggested to comprise biomarkers to track disease progression or could identify new therapeutic targets. While metabolite changes can be measured readily in blood, there is limited knowledge on the effect of blood matrices and sample processing time may have on the stability of KP metabolites. Understanding the stability of KP metabolites in blood is integral to obtaining accurate KP data to correlate with clinical pathology. Hence, the aim of this study was to assess the concentration of KP metabolites in matched whole blood, plasma and serum. The impact of pre-analytical sample processing time in the various blood matrices was also analysed. Serum and plasma had the higher concentration of KP metabolites compared to whole blood. Furthermore, concentrations of KP metabolites declined when the collected blood was processed after 24 hours storage at 4°C. Our study shows that that type of blood matrix and the time to processing have an impact on the stability of the KP metabolites. Serum or plasma are the preferred choice of matrix and the isolation of these matrices from whole blood is best performed immediately after collection for optimal analytical KP data.

Tryptophan extends the life of cytochrome P450

Powerfully oxidizing enzymes need protective mechanisms to prevent self-destruction. The flavocytochrome P450 BM3 from Priestia megaterium (P450BM3) is a self-sufficient monooxygenase that hydroxylates fatty acid substrates using O2 and NADPH as co-substrates. Hydroxylation of long-chain fatty acids (≥C14) is well coupled to O2 and NADPH consumption, but shorter chains (≤C12) are more poorly coupled. Hydroxylation of p-nitrophenoxydodecanoic acid by P450BM3 produces a spectrophotometrically detectable product wherein the coupling of NADPH consumption to product formation is just 10%. Moreover, the rate of NADPH consumption is 1.8 times that of O2 consumption, indicating that an oxidase uncoupling pathway is operative. Measurements of the total number of enzyme turnovers before inactivation (TTN) indicate that higher NADPH concentrations increase TTN. At lower NADPH levels, added ascorbate increases TTN, while a W96H mutation leads to a decrease. The W96 residue is about 7 Å from the P450BM3 heme and serves as a gateway residue in a tryptophan/tyrosine (W/Y) hole transport chain from the heme to a surface tyrosine residue. The data indicate that two oxidase pathways protect the enzyme from damage by intercepting the powerfully oxidizing enzyme intermediate (Compound I) and returning it to its resting state. At high NADPH concentrations, reducing equivalents from the flavoprotein are delivered to Compound I by the usual reductase pathway. When NADPH is not abundant, however, oxidizing equivalents from Compound I can traverse a W/Y chain, arriving at the enzyme surface where they are scavenged by reductants. Ubiquitous tryptophan/tyrosine chains in highly oxidizing enzymes likely perform similar protective functions.

Niacin - a scoping review for Nordic Nutrition Recommendations 2023

Niacin is the precursor to pyridine nucleotides NAD (nicotinamide adenine dinucleotide) and NADP (nicotinamide adenine dinucleotide phosphate). Niacin (vitamin B3) is the common term for nicotinic acid, nicotinamide and derivatives that exhibit the biological activity of nicotinamide. Furthermore, the indispensable amino acid tryptophan is the substrate for de novo synthesis of NAD. Thus, the requirements and intake of niacin are expressed as niacin equivalents (NE). The focus of interest for niacin over the last decade has primarily been on pharmacological doses of nicotinic acid as a lipid-lowering agent and other NAD precursors as potential enhancers of cellular NAD+ concentrations. None of these studies, however, makes a useful contribution to understanding dietary requirements in healthy populations. The requirement for niacin is estimated based on the relationship between intake and biochemical indices of niacin status, primarily urinary excretion of nicotinamide metabolites.

Decreased Plasma Levels of Kynurenine and Kynurenic Acid in Previously Treated and First-Episode Antipsychotic-Naive Schizophrenia Patients

Tryptophan (TRP) catabolites exert neuroactive effects, with the plethora of evidence suggesting that kynurenic acid (KYNA), a catabolite of the kynurenine pathway (KP), acts as the regulator of glutamate and acetylcholine in the brain, contributing to the schizophrenia pathophysiology. Newer evidence regarding measures of KP metabolites in the blood of schizophrenia patients and from the central nervous system suggest that blood levels of these metabolites by no means could reflect pathological changes of TRP degradation in the brain. The aim of this study was to investigate plasma concentrations of TRP, kynurenine (KYN) and KYNA at the acute phase and remission of schizophrenia in a prospective, case-control study of highly selected and matched schizophrenia patients and healthy individuals. Our study revealed significantly decreased KYN and KYNA in schizophrenia patients (p < 0.001), irrespective of illness state, type of antipsychotic treatment, number of episodes or illness duration and no differences in the KYN/TRP ratio between schizophrenia patients and healthy individuals. These findings could be interpreted as indices that kynurenine pathway might not be dysregulated in the periphery and that other factors contribute to observed disturbances in concentrations, but as our study had certain limitations, we cannot draw definite conclusions. Further studies, especially those exploring other body compartments that participate in kynurenine pathway, are needed.

Therapeutic effects of in vivo administration of an inhibitor of tryptophan 2,3-dioxygenase (680c91) for the treatment of fibroids: a preclinical study

OBJECTIVE

Fibroids are characterized by marked overexpression of tryptophan 2,3 dioxygenase (TDO2). The objective of this study was to determine the effectiveness of in vivo administration of an inhibitor of TDO2 (680C91) on fibroid size and gene expression.

DESIGN

Animal and ex vivo human study.

SETTING

Academic Research Institution.

SUBJECTS

Severe combined immunodeficiency mice bearing human fibroid xenografts treated with vehicle and TDO2 inhibitor.

INTERVENTION

Daily intraperitoneal administration of 680C91 or vehicle for 2 months and in vitro studies with fibroid explants.

MAIN OUTCOME MEASURES

Tumor weight and gene expression profile of xenografts and in vitro mechanistic experiments using fibroid explants.

RESULTS

Compound 680C91 was well-tolerated with no effects on blood chemistry and body weight. Treatment of mice with 680C91 resulted in 30% reduction in the weight of fibroid xenografts after 2 months of treatment and as expected lower levels of kynurenine, the byproduct of tryptophan degradation and an endogenous ligand of aryl hydrocarbon receptor (AhR) in the xenografts. The expression of cytochrome P450 family 1 subfamily B member 1 (CYP1B1), transforming growth factor β3 (TGF-β3), fibronectin (FN1), cyclin-dependent kinase 2 (CDK2), E2F transcription factor 1 (E2F1), interleukin 8 (IL-8) and secreted protein acidic and cysteine rich (SPARC) mRNA were lower in the xenografts of mice treated with 680C91 compared with vehicle controls. Similarly, the protein abundance of collagen, FN1, CYP1B1, and SPARC were lower in the xenografts of 680C9- treated mice compared with vehicle controls. Immunohistochemical analysis of xenografts indicated decreased expression of collagen, Ki67 and E2F1 but no significant changes in cleaved caspase 3 expression in mice treated with 680C91. The levels of kynurenine in the xenografts showed a direct correlation with the tumor weight and FN1 levels. In vitro studies with fibroid explants showed a significant induction of CYP1B1, TGF-β3, FN1, CDK2, E2F1, IL8, and SPARC mRNA by tryptophan, which could be blocked by cotreatment with 680C91 and the AhR antagonist CH-223191.

CONCLUSION

The results indicate that correction of aberrant tryptophan catabolism in fibroids could be an effective treatment through its effect to reduce cell proliferation and extracellular matrix accumulation.

C-undecylcalix[4]resorcinarene Langmuir-Blodgett/Porous Reduced Graphene Oxide Composite Film as a Electrochemical Sensor for the Determination of Tryptophan

In this study, a composite film was developed for the electrochemical sensing of tryptophan (Trp). Porous reduced graphene oxide (PrGO) was utilized as the electron transfer layer, and a C-undecylcalix[4]resorcinarene Langmuir-Blodgett (CUCR-LB) film served as the molecular recognition layer. Atomic force microscopy (AFM), transmission electron microscopy (TEM), Raman spectroscopy, scanning electron microscopy (SEM), and electrochemical experiments were employed to analyze the characteristics of the CUCR-LB/PrGO composite film. The electrochemical behavior of Trp on the CUCR-LB/PrGO composite film was investigated, revealing a Trp linear response range of 1.0 × 10-7 to 3.0 × 10-5 mol L-1 and a detection limit of 3.0 × 10-8 mol L-1. Furthermore, the developed electroanalytical method successfully determined Trp content in an amino acid injection sample. This study not only introduces a rapid and reliable electrochemical method for the determination of Trp but also presents a new strategy for constructing high-performance electrochemical sensing platforms.