Trp Levels Research Articles

Sustainable and efficient monitoring of tryptophan and tyrosine serum levels: a green HPTLC method as a biomarker for type 2 diabetes

In recent years, there has been considerable interest in using amino acids like tryptophan (Trp) and tyrosine (Tyr) as biomarkers for various diseases, including type 2 diabetes mellitus (T2D). In diseases like T2D, the metabolism of Trp and Tyr is altered. The activity of enzymes involved in Trp metabolism increases, leading to a decrease in its serum level. On the other hand, the serum level of Tyr increases due to the suppressed activity of its metabolizing enzymes. These observations suggest that Trp and Tyr metabolism may play a crucial role in the pathophysiology of type 2 diabetes. Our study highlights the potential utility of Trp and Tyr as biomarkers for the early detection, prognosis, and monitoring of this metabolic disorder. Given these observations, we aimed to develop a high-performance thin-layer chromatographic (HPTLC) method that is sensitive, selective, rapid, and environmentally friendly for estimating the concentrations of Trp and Tyr in biological fluids, particularly serum samples. To evaluate the method, we performed analysis using serum samples from controlled and streptozotocin-induced diabetic rats. Our main objective was to develop a method that is sensitive and selective for precisely determining Trp and Tyr serum levels, which could serve as potential biomarkers for T2D. Fluorescence and absorption modes were employed for densitometry scanning. We assessed the precision and high separation efficiency of the chromatographic system by calculating parameters such as separation and resolution factors, number of theoretical plates, and height equivalent to theoretical plates. To evaluate the environmental impact of our proposed method, we employed the AGREE (Analytical GREEnness metric) and GAPI (Green Analytical Procedure Index) greenness assessment tools. The results confirmed that our method is environmentally friendly and exhibits superior eco-friendliness and greenness compared to other reported methods.Graphical

Unveiling the influences of P fertilization on bioactive compounds and antioxidant activity in grains of four sorghum cultivars.

Phosphorus is a critical nutrient in agriculture, influencing plant growth and nutritional quality. This study, uniquely designed to investigate the effects of phosphorus (P) fertilization levels, sorghum cultivars, and growing locations on phytochemical content and antioxidant activity in sorghum grains, employed four sorghum cultivars (Hakeka, P954063, Tabat, and Tetron) grown under three P levels (0P, 1P, 2P) in two locations (Gezira and White Nile) in Sudan. In this study, four sorghum cultivars were grown in two distinct locations in Sudan, employing a split-plot design with three (P) fertilization levels. P was applied as triple super phosphate directly with the seeds, and additional fertilization included urea applied in two split doses. At physiological maturity, representative sorghum panicles were harvested, processed, and analyzed for bioactive compounds and antioxidant activities using standard extraction and quantification techniques such as Folin-Ciocalteu for phenolics and colorimetric flavonoid assays. Antioxidant activities were assessed through various assays, including DPPH and FRAP. Statistical analyses were performed using a three-way ANOVA to examine the effects of cultivar, P level, and location on the measured parameters, supplemented by multivariate analysis to further elucidate the interactions between these factors. Significant interactions (p<0.001) were observed among cultivars, P levels, and locations for total phenolic content (TPC), total flavonoid content (TFC), carotenoids, tannins, and various antioxidant activity measures (DPPH, FRAP, ABTS, TRP, H2O2). P fertilization significantly increased all measured phytochemicals and antioxidant activities compared to non-treated cultivars, except for H2O2, which decreased with P application. Among cultivars, Hakeka consistently exhibited the highest TFC, carotenoid content, and antioxidant activities (DPPH, FRAP, TRP, ABTS), particularly at the 2P level. P954063 showed the highest TPC and tannin concentrations. Tetron generally had the lowest phytochemical and antioxidant levels. White Nile showed higher TPC, carotenoids, DPPH, FRAP, TRP, and ABTS levels, while Gezira had higher TFC, tannins, and H2O2 concentrations. The impact of phosphorus fertilization often varies between locations. Strong positive correlations were found between TPC and all antioxidant assays (r = 0.68-0.90) and total carotenoids and antioxidant activities (r = 0.73-0.93). This study recommended cultivating the Tabat variety with 2P doses in Gezira. In addition, the Hakeka cultivar showed the highest increases in total flavonoid content, carotenoids, and antioxidant activities, particularly under the highest P level (2P). The findings highlight that P plays a critical role in enhancing sorghum's nutritional and health-promoting qualities, which are essential for leveraging this staple crop for food and nutrition security strategies in semi-arid regions.

The effect of prebiotic supplementation on serum levels of tryptophan and kynurenine in obese women with major depressive disorder: a double-blinded placebo-controlled randomized clinical trial

ObjectiveThe objective of the present study was to examine the effect of calorie restricted diet (CRD) plus inulin supplementation on serum levels of tryptophan (Trp), kynurenine (Kyn) and Trp/Kyn ratio in obese women with major depressive disorder (MDD).ResultsIn this double-blind placebo-controlled randomized clinical trial, 51 obese women (BMI = 30–40 kg/m2) with mild MDD were assessed for depression level using Hamilton depression rating scale (HDRS). The patients were randomly allocated into either “Prebiotic group” (received 10 g/day inulin) or “Placebo group” (received 10 g/day maltodextrin). All participants also received individualized CRD. Fasting serum levels of Trp, Kyn, and Trp/Kyn ratio were assessed at baseline and after 8 weeks. Results showed slightly greater increases in serum levels of Trp and Trp/Kyn ratio as well as reductions in serum level of Kyn and HDRS score in prebiotic group than placebo group. However, between group differences in these parameters as well as HDRS score were not statistically significant after adjusting for baseline variables at the end of the trial. Results indicates that CRD accompanied by inulin supplementation (10 g/day) did not influence serum levels of Trp, Kyn and Trp/Kyn ratio as well as HDRS score after 8 weeks.Trial registration: The trial was registered in the Iranian registry of clinical trials at 2018-08-02 (https://www.irct.ir/; registration number: IRCT20100209003320N15).

Effects of Tryptophan and Physical Exercise on the Modulation of Mechanical Hypersensitivity in a Fibromyalgia-like Model in Female Rats.

Though the mechanisms are not fully understood, tryptophan (Trp) and physical exercise seem to regulate mechanical hypersensitivity in fibromyalgia. Here, we tested the impact of Trp supplementation and continuous low-intensity aerobic exercise on the modulation of mechanical hypersensitivity in a fibromyalgia-like model induced by acid saline in female rats. Twelve-month-old female Wistar rats were randomly divided into groups: [control (n = 6); acid saline (n = 6); acid saline + exercise (n = 6); acid saline + Trp (n = 6); and acid saline + exercise + Trp (n = 6)]. Hypersensitivity was caused using two intramuscular jabs of acid saline (20 μL; pH 4.0; right gastrocnemius), 3 days apart. The tryptophan-supplemented diet contained 7.6 g/hg of Trp. The three-week exercise consisted of progressive (30-45 min) treadmill running at 50 to 60% intensity, five times (Monday to Friday) per week. We found that acid saline induced contralateral mechanical hypersensitivity without changing the levels of Trp, serotonin (5-HT), and kynurenine (KYN) in the brain. Hypersensitivity was reduced by exercise (~150%), Trp (~67%), and its combination (~160%). The Trp supplementation increased the levels of Trp and KYN in the brain, and the activity of indoleamine 2,3-dioxygenase (IDO), and decreased the ratio 5-HT:KYN. Exercise did not impact the assessed metabolites. Combining the treatments reduced neither hypersensitivity nor the levels of serotonin and Trp in the brain. In conclusion, mechanical hypersensitivity induced by acid saline in a fibromyalgia-like model in female rats is modulated by Trp supplementation, which increases IDO activity and leads to improved Trp metabolism via the KYN pathway. In contrast, physical exercise does not affect mechanical hypersensitivity through brain Trp metabolism via either the KYN or serotonin pathways. Because this is a short study, generalizing its findings warrants caution.

Effects of different forms of amino acid supplementation on the performance and intestinal barrier function of laying hens fed a low-protein diet

The aim of this study was to investigate the effects of low-protein diets and the sustained release of synthetic amino acids (AA) on the performance, intestinal barrier function and nitrogen excretion of laying hens. Two hundred eighty-eight 39-week-old Hyline brown laying hens of were randomly divided into 3 groups with 8 replicates per group. The crude protein level in the control group (CON) was 16%, the crude protein levels in the crystal AA supplement group (LCP-CAA) and microencapsulated AA group (LCP-MAA) were both 13%, and the AA levels in the LCP-CAA and LCP-MAA groups were consistent with that in the CON group. The experiment lasted 12 wk, and production performance was assessed weekly. The FCR and ADFI values were significantly greater for the LCP-CAA group than for the CON and LCP-MAA groups (P < 0.05). Two hours after feeding, His levels were significantly greater in the LCP-CAA group than in the LCP-MAA group (P < 0.05); 4 h after feeding, the contents of Met, Thr, Leu and Val were significantly greater in blood from the LCP-MAA group (P < 0.05); 6 h after feeding, Trp, Ile and Arg levels were significantly greater in the LCP-MAA group (P < 0.05). The chylase content significantly decreased in the duodenum of the LCP-CAA group (P < 0.05), and the chylase and trypsin were contents increased in the ileum of the LCP-MAA group (P < 0.05). In the LCP-MAA group, significantly increased mRNA expression levels of Occludin, ZO-1 in duodenum; Occludin, ZO-1, y+LAT1 in jejunum; and ZO-1 in ileum were detected at 8 and 12 weeks (P < 0.05). The fecal nitrogen content significantly decreased in the low protein diet group (P < 0.01). In conclusion, reducing dietary crude protein levels and supplementing with microencapsulated AAs can improve intestinal barrier function, promote digestive enzyme secretion, increase the expression of AA transporters, improve dietary protein utilization efficiency, and reduce nitrogen emission in laying hens.

The association of aromatic amino acids with coronary artery disease and major adverse cardiovascular events in a Chinese population

This study aimed to evaluate the relationship between aromatic amino acids (AAAs), – phenylalanine (Phe), tyrosine (Tyr) and tryptophan (Trp) – and coronary artery disease (CAD) in a prospective study involving 2970 participants undergoing coronary angiography at Beijing Hospital. Serum levels of Phe, Tyr and Trp were analysed. The cross-sectional data revealed that serum Tyr and Trp levels were significantly and inversely associated with CAD. During a median follow-up period of 44 months, 343 major adverse cardiovascular events (MACEs) and 138 all-cause deaths were recorded. MACE included myocardial infarction, stroke, revascularisation and all-cause mortality. Low serum Trp levels predicted an increased risk of MACE and death. High serum Phe levels were linked to an increased risk of MACE, while low Tyr levels were associated with a higher risk of death. Collectively, our findings underscore a close correlation between AAAs and CAD, as well as their potential predictive value for adverse cardiovascular outcomes.

Insights into Ligand-Mediated Activation of an Oligomeric Ring-Shaped Gene-Regulatory Protein from Solution- and Solid-State NMR

The 91 kDa oligomeric ring-shaped ligand binding protein TRAP (trp RNA binding attenuation protein) regulates the expression of a series of genes involved in tryptophan (Trp) biosynthesis in bacilli. When cellular Trp levels rise, the free amino acid binds to sites buried in the interfaces between each of the 11 (or 12, depending on the species) protomers in the ring. Crystal structures of Trp-bound TRAP show the Trp ligands are sequestered from solvent by a pair of loops from adjacent protomers that bury the bound ligand via polar contacts to several threonine residues. Binding of the Trp ligands occurs cooperatively, such that successive binding events occur with higher apparent affinity but the structural basis for this cooperativity is poorly understood. We used solution methyl-TROSY NMR relaxation experiments focused on threonine and isoleucine sidechains, as well as magic angle spinning solid-state NMR 13C–13C and 15N-13C chemical shift correlation spectra on uniformly labeled samples recorded at 800 and 1200 MHz, to characterize the structure and dynamics of the protein. Methyl 13C relaxation dispersion experiments on ligand-free apo TRAP revealed concerted exchange dynamics on the µs-ms time scale, consistent with transient sampling of conformations that could allow ligand binding. Cross-correlated relaxation experiments revealed widespread disorder on fast timescales. Chemical shifts for methyl-bearing side chains in apo- and Trp-bound TRAP revealed subtle changes in the distribution of sampled sidechain rotameric states. These observations reveal a pathway and mechanism for induced conformational changes to generate homotropic Trp-Trp binding cooperativity.

Functional analysis of the novel mitochondrial tRNATrp and tRNASer(AGY) variants associated with type 2 diabetes mellitus.

Mutations in mitochondrial tRNA (mt-tRNA) genes that result in mitochondrial dysfunction play important roles in type 2 diabetes mellitus (T2DM). We pre-viously reported a large Chinese pedigree with maternally inherited T2DM that harbors novel mt-tRNA Trp A5514G and tRNA Ser(AGY) C12237T variants, however, the effects of these mt-tRNA variants on T2DM progression are largely unknown. To assess the potential pathogenicity of T2DM-associated m.A5514G and m.C12237T variants at genetic, molecular, and biochemical levels. Cytoplasmic hybrid (cybrid) cells carrying both m.A5514G and m.C12237T variants, and healthy control cells without these mitochondrial DNA (mtDNA) variants were generated using trans-mitochondrial technology. Mitochondrial features, including mt-tRNA steady-state level, levels of adenosine triphosphate (ATP), mitochondrial membrane potential (MMP), reactive oxygen species (ROS), mtDNA copy number, nicotinamide adenine dinucleotide (NAD+)/NADH ratio, enzymatic activities of respiratory chain complexes (RCCs), 8-hydroxy-deo-xyguanine (8-OhdG), malondialdehyde (MDA), and superoxide dismutase (SOD) were examined in cell lines with and without these mt-tRNA variants. Compared with control cells, the m.A5514G variant caused an approximately 35% reduction in the steady-state level of mt-tRNA Trp (P < 0.0001); however, the m.C12237T variant did not affect the mt-tRNA Ser(AGY) steady-state level (P = 0.5849). Biochemical analysis revealed that cells with both m.A5514G and m.C12237T variants exhibited more severe mitochondrial dysfunctions and elevated oxidative stress than control cells: ATP, MMP, NAD+/NADH ratio, enzyme activities of RCCs and SOD levels were markedly decreased in mutant cells (P < 0.05 for all measures). By contrast, the levels of ROS, 8-OhdG and MDA were significantly increased (P < 0.05 for all measures), but mtDNA copy number was not affected by m.A5514G and m.C12237T variants (P = 0.5942). The m.A5514G variant impaired mt-tRNA Trp metabolism, which subsequently caused mitochondrial dysfunction. The m.C12237T variant did not alter the steady-state level of mt-tRNA Ser(AGY), indicating that it may be a modifier of the m.A5514G variant. The m.A5514G variant may exacerbate the pathogenesis and progression of T2DM in this Chinese pedigree.

A metabolic constraint in the kynurenine pathway drives mucosal inflammation in IBD.

Inflammatory bowel disease (IBD) is associated with perturbed metabolism of the essential amino acid tryptophan (Trp). Whether increased degradation of Trp directly fuels mucosal inflammation or acts as a compensatory attempt to restore cellular energy levels via de-novo nicotinamide adenine dinucleotide (NAD + ) synthesis is not understood. Employing a systems medicine approach on longitudinal IBD therapy intervention cohorts and targeted screening in preclinical IBD models, we discover that steady increases in Trp levels upon therapy success coincide with a rewiring of metabolic processes within the kynurenine pathway (KP). In detail, we identify that Trp catabolism in IBD is metabolically constrained at the level of quinolinate phosphorybosyltransferase (QPRT), leading to accumulation of quinolinic acid (Quin) and a decrease of NAD + . We further demonstrate that Trp degradation along the KP occurs locally in the inflamed intestinal mucosa and critically depends on janus kinase / signal transducers and activators of transcription (JAK/STAT) signalling. Subsequently, knockdown of QPRT in-vitro induces NAD + depletion and a pro-inflammatory state, which can largely be rescued by bypassing QPRT via other NAD + precursors. We hence propose a model of impaired de-novo NAD + synthesis from Trp in IBD. These findings point towards the replenishment of NAD + precursors as a novel therapeutic pathway in IBD.

Effects of phototherapy on biopterin, neopterin, tryptophan, and behavioral neuroinflammatory reaction in patients with post-stroke depression

The aim of this study was to investigate the overall effects of phototherapy on biopterin (BH4), neopterin (BH2), tryptophan (Trp), and behavioral neuroinflammatory reaction in patients with post-stroke depression. There involved a total of 100 hospitalized patients with post-stroke depression at our hospital from February 2021 to December 2022. The participants enrolled were randomly assigned to either the control group or the experimental group. The control group received routine treatment, including medication and psychological support, while the experimental group received 30 min of phototherapy daily for 8 weeks. All participantsvoluntarily participated in the study and provided informed consent. Baseline characteristics of the patients were statistically analyzed. The severity of depressive symptoms was evaluated using the hamilton depression scale (HAMD) and the beck depression inventory (BDI). Levels of amino acid neurotransmitters, including gamma-aminobutyric acid (GABA), aspartic acid (Asp), and glutamic acid (Glu), were measured using radioimmunoassay. Plasma levels of neuroinflammatory factors, such as TNF-α, IL-6, and IL-1β were, determined using ELISA. Plasma levels of BH4, BH2, and Trp were detected by HPLC. Levels of SOD, GPx, CAT, and MDA in plasma were measured using corresponding kits and colorimetry. Quality of life was assessed using the SF-36 scale. There were no differences in baseline characteristic between the two groups (P > 0.05). The HAMD and BDI scores in the experimental group were lower than those in the control group (P < 0.05), indicating phototherapy could reduce the severity of post-stroke depression. The levels of GABA, Glu, and Asp in both groups significantly increased after treatment compared to their respective levels before treatment (P < 0.01).The levels of GABA in the experimental group were higher than those in the control group (P < 0.01),while the levels of Glu, and Asp were lower than those in the control group (P < 0.01). The plasma levels of TNF-α, IL-6, and IL-1β in the experimental group were evidently lower than those in the control group (P < 0.05). Moreover, the levels of BH4 and Trp in experimental group were significantly higher than those in the control group (P < 0.05), while the levelsof BH2 in the experimental group were significantly lower than the control group (P < 0.05). Additionally, the levels of SOD, GPx, and CAT in the experimental group were evidently higher than those in the control group (P < 0.05), whereas the levels of MDA in the experimental group were significantly lower than control group (P < 0.05). The experimental group showed higher scores in physical function, mental health, social function, and overall health compared to the control group (P < 0.05). Phototherapy exerted a profound impact on the metabolism of BH4, BH2, and Trp, as well as on behavioral neuroinflammatory reactions and the quality of life in patients suffering from post-stroke depression. Through its ability to optimize the secretion and synthesis of neurotransmitters, phototherapy effectively regulated neuroinflammatory reactions, improved biochemical parameters, enhancedantioxidant capacity, and alleviated depressive symptoms. As a result, phototherapy was considered a valuable adjuvant therapeutic approach for patients with post-stroke depression.

Exploring the kynurenine pathway in mild traumatic brain injury: A longitudinal study.

A potential source of novel biomarkers for mTBI is the kynurenine pathway (KP), a metabolic pathway of tryptophan (Trp), that is up-regulated by neuroinflammation and stress. Considering that metabolites of the KP (kynurenines) are implicated in various neuropsychiatric diseases, exploration of this pathway could potentially bridge the gap between physiological and psychological factors in the recovery process after mTBI. This study, therefore, set out to characterize the KP after mTBI and to examine associations with long-term outcome. Patients were prospectively recruited at the emergency department (ED), and blood samples were obtained in the acute phase (<24 h; N = 256) and at 1-month follow-up (N = 146). A comparison group of healthy controls (HC; N = 32) was studied at both timepoints. Trp, kynurenines, and interleukin (IL)-6 and IL-10 were quantified in plasma. Clinical outcome was measured at six months post-injury. Trp, xanthurenic acid (XA), and picolinic acid (PA) were significantly reduced in patients with mTBI relative to HC, corrected for age and sex. For Trp (d = -0.57 vs. d = -0.29) and XA (d = -0.98 vs. d = -0.32), larger effects sizes were observed during the acute phase compared to one-month follow-up, while for PA (d = -0.49 vs. d = -0.52) effect sizes remained consistent. Findings for other kynurenines (e.g., kynurenine, kynurenic acid, and quinolinic acid) were non-significant after correction for multiple testing. Within the mTBI group, lower acute Trp levels were significantly related to incomplete functional recovery and higher depression scores at 6 months post-injury. No significant relationships were found for Trp, XA, and PA with IL-6 or IL-10 concentrations. In conclusion, our findings indicate that perturbations of the plasma KP in the hyperacute phase of mTBI and 1 month later are limited to the precursor Trp, and glutamate system modulating kynurenines XA and PA. Correlations between acute reductions of Trp and unfavorable outcomes may suggest a potential substrate for pharmacological intervention.

Tryptophan regulates sorghum root growth and enhances low nitrogen tolerance

Over evolutionary time, plants have developed sophisticated regulatory mechanisms to adapt to fluctuating nitrogen (N) environments, ensuring that their growth is balanced with their responses to N stress. This study explored the potential of L-tryptophan (Trp) in regulating sorghum root growth under conditions of N limitation. Here, two distinct sorghum genotypes (low-N tolerance 398B and low-N sensitive CS3541) were utilized for investigating effect of low-N stress on root morphology and conducting a comparative transcriptomics analysis. Our foundings indicated that 398B exhibited longer roots, greater root dry weights, and a higher Trp content compared to CS3541 under low-N conditions. Furthermore, transcriptome analysis revealed substantial differences in gene expression profiles related to Trp pathway and carbon (C) and N metabolism pathways between the two genotypes. Additional experiments were conducted to assess the effects of exogenous Trp treatment on the interplay between sorghum root growth and low-N tolerance. Our observations showed that Trp-treated plants developed longer root and had elevated levels of Trp and IAA under low-N conditons. Concurrently, these plants demonstrated stronger physiological activities in C and N metabolism when subjected to low-N stress. These results underscored the pivotal role of Trp on root growth and low-N stress responses by balancing IAA levels and C and N metabolism. This study not only deepens our understanding of how plants maintain growth plasticity during environmental stress but also provides valuable insights into the availability of amino acid in crops, which could be instrumental in developing strategies for promoting crop resilience to N deficiency.

PSV-15 Effect of functional amino acids and fiber on growth performance of post-weaning pigs

Abstract This study evaluated the effect of increasing levels of functional amino acids (FAA), including Met, Thr, and Trp with 1.4% standardized ileal digestible (SID) Lys on performance and the effect of high levels of fiber when high levels of FAA combined. A total of 216 pigs [21 d old; 6.46 ± 0.63 kg body weight (BW)] were allotted to one of 6 treatments with 3 pigs of single sex per pen, and 12 replicates/treatment. Treatments were: 1) Control basal diet (BD), 2) BD + 23% more Met+Cys (HMet), 3) BD + 22% more Thr (HThr), 4) BD + 20% more Trp (HTrp), 5) BD + 20% more Met, Thr, and Trp (HFAA, with 9% NDF and 4%ADF), 6) HFAA+ high fiber (27% NDF and 18% ADF in diet by adding soy hulls at expense of corn, HFAA+HF). The experiment lasted for 42 d and pigs were fed experimental diets for 21 d followed by a common diet for the last 21 d. Pigs fed HFAA+HF diet were initially fed HFAA diet for the first 8 d and followed by HFAA+HF diet for the next 13 d, and fed the common diet during the last 21 d. On d 0, 9, 21, and 42, BW and feed intake were recorded, and fecal scores (1 as normal to 4 as watery diarrhea) were assessed during the trial. Data were analyzed using the lme4 package of R 4.1.2, and the statistical models included the fixed effect of treatment and random effect of sex and BW block. Growth performance data were analyzed as single factor ANOVA, whereas stool quality was analyzed using ordinal model. Contrasts were used to test the effects of FAA (by comparing treatments 2, 3, 4, and 5 to BD) and fiber (by comparing HFAA+HF to HFAA). Pigs fed HFAA had reduced (P &amp;lt; 0.05) average daily gain (ADG) and average daily feed intake (ADFI) from d 21 to 42 and tended (P &amp;lt; 0.10) to have reduced overall ADG compared with BD (Table 1). Increasing individual amino acids did not affect performance, with the exception that pigs fed HTrp tended (P &amp;lt; 0.10) to have increased gain to feed ratio (G:F) from d 21 to 42 compared with BD. Greater fiber content did not affect ADG or ADFI; however, it reduced (P &amp;lt; 0.05) G:F during the whole trial compared with HFAA. Treatment did not influence stool quality. In conclusion, combination of increased amounts of Met, Thr, and Trp with SID 1.4% Lys under non-disease challenged conditions resulted in a reduction of performance, but this was not the case with increased individual amino acids, and increased fiber content with increased FAA which reduced feed efficiency of pigs.

Salivary Tryptophan as a Metabolic Marker of HER2-Negative Molecular Subtypes of Breast Cancer.

Changes in the concentration of tryptophan (Trp) indicate a serious metabolic restructuring, which is both a cause and a consequence of many diseases. This work examines the upward change in salivary Trp concentrations among patients with breast cancer. This study involved volunteers divided into three groups: breast cancer (n = 104), non-malignant breast pathologies (n = 30) and healthy controls (n = 20). In all participants, before treatment, the quantitative content of Trp in saliva was determined by capillary electrophoresis. In 20 patients with breast cancer, Trp was re-tested four weeks after surgical removal of the tumor. An increase in the Trp content in saliva in breast cancer has been shown, which statistically significantly decreases after surgical removal of the tumor. A direct correlation was found between increased Trp levels with the degree of malignancy and aggressive molecular subtypes of breast cancer, namely triple negative and luminal B-like HER2-negative. These conclusions were based on an increase in Ki-67 and an increase in Trp in HER2-negative and progesterone-negative subtypes. Factors under which an increase in Trp concentration in saliva was observed were identified: advanced stage of breast cancer, the presence of regional metastasis, low tumor differentiation, a lack of expression of HER2, estrogen and progesterone receptors and the high proliferative activity of the tumor. Thus, the determination of salivary Trp may be a valuable tool in the study of metabolic changes associated with cancer, particularly breast cancer.

Immunoregulatory and antioxidant properties of tryptophan in quail chick

A dose-response assay was carried out to investigate the effects of graded levels of dietary tryptophan (Trp) on blood variables, immunity, and meat quality in quail chicks during the last two weeks of the growing period. A total of 420 21-day-old quail chicks were randomly distributed across the seven experimental groups (i.e., 2.12, 2.25, 2.38, 2.51, 2.64, 2.77, and 2.90 g Trp/kg of diet) with four pen replicates of 15 birds each. Blood variables, including uric acid (UA), albumin (ALB), and triglycerides (TG), responded inversely to increasing dietary Trp (P < 0.001). The concentration of aspartate aminotransferase (AST) in serum, the relative weight of bursa of Fabricius (BF), immunoglobulin G (IgG), water holding capacity (WHC), and antigen production against the sheep red blood cells (SRBC) increased with increasing dietary Trp (P < 0.001). In contrast, the concentration of malondialdehyde (MDA) and drip loss in meat samples decreased with increasing dietary Trp (P < 0.001). The best models for optimal dietary Trp were identified based on a statistical merit basis known as the model accuracy index (δ). The estimated dietary Trp for optimizing ALP, UA, total protein (TP), TG, SRBC, IgG, BF, drip loss, WHC, and MDA were obtained at 2.347, 2.371, 2,372, 2.485, 2,691, 2.738, 2.306, 2.359, 2.247, and 2.500 g/kg of diet, respectively. Principal component analysis showed that UA, TG, IgG, and drip loss had a higher association with dietary Trp rather than other responses. Considering the high δ and eigenvalues of the models, the best estimation of dietary Trp level required for the optimization of the studied traits in quail chicks would be 2.738 g Trp/kg of diet, which was significantly higher than that recommended for the quail performance by NRC (1994).

Tryptophan degradation as a systems phenomenon in inflammation – an analysis across 13 chronic inflammatory diseases

Chronic inflammatory diseases (CIDs) are systems disorders that affect diverse organs including the intestine, joints and skin. The essential amino acid tryptophan (Trp) can be broken down to various bioactive derivatives important for immune regulation. Increased Trp catabolism has been observed in some CIDs, so we aimed to characterise the specificity and extent of Trp degradation as a systems phenomenon across CIDs. We used high performance liquid chromatography and targeted mass spectrometry to assess the serum and stool levels of Trp and Trp derivatives. Our retrospective study incorporates both cross-sectional and longitudinal components, as we have included a healthy population as a reference and there are also multiple observations per patient over time. We found reduced serum Trp levels across the majority of CIDs, and a prevailing negative relationship between Trp and systemic inflammatory marker C-reactive protein (CRP). Notably, serum Trp was low in several CIDs even in the absence of measurable systemic inflammation. Increases in the kynurenine-to-Trp ratio (Kyn:Trp) suggest that these changes result from increased degradation along the kynurenine pathway. Increases in Kyn:Trp indicate the kynurenine pathway as a major route for CID-related Trp metabolism disruption and the specificity of the network changes indicates excessive Trp degradation relative to other proteogenic amino acids. Our results suggest that increased Trp catabolism is a common metabolic occurrence in CIDs that may directly affect systemic immunity. This work was supported by the DFG Cluster of Excellence 2167 "Precision medicine in chronic inflammation" (KA, SSchr, PR, BH, SWa), the BMBF (e:Med Juniorverbund "Try-IBD" 01ZX1915A and 01ZX2215, the e:Med Network iTREAT 01ZX2202A, and GUIDE-IBD 031L0188A), EKFS (2020_EKCS.11, KA), DFG RU5042 (PR, KA), and Innovative Medicines Initiative 2 Joint Undertakings ("Taxonomy, Treatments, Targets and Remission", 831434, "ImmUniverse", 853995, "BIOMAP", 821511).

Shen Yuan extract exerts a hypnotic effect via the tryptophan/5-hydroxytryptamine/melatonin pathway in mice

Ethnopharmacological relevanceSleep plays a critical role in several physiologic processes, and sleep disorders increase the risk of depression, dementia, stroke, cancer, and other diseases. Stress is one of the main causes of sleep disorders. Ginseng Radix et Rhizoma and Polygalae Radix have been reported to have effects of calming the mind and intensifying intelligence in Chinese Pharmacopoeia. Traditional Chinese medicine prescriptions composed of Ginseng Radix et Rhizoma and Polygalae Radix (Shen Yuan, SY) are commonly used to treat insomnia, depression, and other psychiatric disorders in clinical practice. Unfortunately, the underlying mechanisms of the SY extract's effect on sleep are still unknown. Aim of the studyThis study aimed to investigate the hypnotic effect of the SY extract in normal mice and mice with chronic restraint stress (CRS)-induced sleep disorders and elucidate the underlying mechanisms. Materials and methodsThe SY extract (0.5 and 1.0 g/kg) was intragastrically administered to normal mice for 1, 14, and 28 days and to CRS-treated mice for 28 days. The open field test (OFT) and pentobarbital sodium-induced sleep test (PST) were used to evaluate the hypnotic effect of the SY extract. Liquid chromatography-tandem mass spectrometry and enzyme-linked immunosorbent assay were utilized to detect the levels of neurotransmitters and hormones. Molecular changes at the mRNA and protein levels were determined using real-time quantitative polymerase chain reaction and Western blot analysis to identify the mechanisms by which SY improves sleep disorders. ResultsThe SY extract decreased sleep latency and increased sleep duration in normal mice. Similarly, the sleep duration of mice subjected to CRS was increased by administering SY. The SY extract increased the levels of tryptophan (Trp) and 5-hydroxytryptamine (5-HT) and the expression of tryptophan hydroxylase 2 (TPH2) in the cortex of normal mice. The SY extract increased the Trp level, transcription and expression of estrogen receptor beta and TPH2 in the cortex in mice with sleep disorders by decreasing the serum corticosterone level, which promoted the synthesis of 5-HT. Additionally, the SY extract enhanced the expression of arylalkylamine N-acetyltransferase, which increased the melatonin level and upregulated the expressions of melatonin receptor-2 (MT2) and Cryptochrome 1 (Cry1) in the hypothalamus of mice with sleep disorders. ConclusionsThe SY extract exerted a hypnotic effect via the Trp/5-HT/melatonin pathway, which augmented the synthesis of 5-HT and melatonin and further increased the expressions of MT2 and Cry1.

Dysfunction in endocannabinoids, palmitoylethanolamide, and degradation of tryptophan into kynurenine in individuals with depressive symptoms

BackgroundThe endocannabinoid (eCB) system and the serotonin (5-HT) are both implicated in the severity of the depression. 5-HT is synthesized from the amino acid tryptophan (Trp), which is also a precursor for kynurenine (Kyn) whose production is increased at the expense of 5-HT in depressed patients. No clinical studies have investigated the crosstalk between the eCB system and the Trp/5-HT/Kyn pathways. Here, we hypothesized that the eCB system is associated with an enhanced Kyn production in relation to the severity of depressive symptoms.MethodsEighty-two subjects (51 patients with a diagnosis of depressive disorder (DSM-5) and 31 healthy volunteers), were assessed with the Montgomery-Åsberg Depression Rating Scale (MADRS), Beck Depression Scale, and Global Clinical Impression. Serum concentrations of eCBs (N-arachidonoylethanolamine (AEA) and 2-arachidonoylglycerol (2-AG)); structurally related fatty acyl compounds 2-oleoylglycerol (2-OG), oleoylethanolamide (OEA), and palmitoylethanolamide (PEA); Trp, Kyn, Kyn/Trp ratio (an index of Trp degradation into Kyn) and 5-HT were also determined.ResultsFollowing a principal component analysis including the severity of depression, Kyn and the Kyn/Trp ratio appear to be directly associated with 2-AG, AEA, and PEA. Interestingly, these biomarkers also permitted to distinguish the population into two main clusters: one of individuals having mild/severe depressive symptoms and the other with an absence of depressive symptoms. Using parametric analysis, higher serum levels of 2-AG, Kyn, and the ratio Kyn/Trp and lower levels of Trp and 5-HT were found in individuals with mild/severe depressive symptoms than in those without depressive symptoms. While in asymptomatic people, PEA was directly associated to Trp, and OEA indirectly linked to 5-HT, in individuals with depressive symptoms, these correlations were lost, and instead, positive correlations between AEA and 2-AG, PEA and AEA, and PEA vs 2-AG and OEA concentrations were found.ConclusionsParametric and non-parametric analyses suggest a possible association between eCBs, tryptophan/kynurenine biomarkers, and severity of depression, confirming a likely interplay among inflammation, stress, and depression. The enhanced relationships among the biomarkers of the 2-AG and AEA pathways and related lipids seen in individuals with depressive symptoms, but not in asymptomatics, suggest an altered metabolism of the eCB system in depression.

Investigation of tryptophan to kynurenine degradation in response to interferon-γ in melanoma cell lines

Background and aimMelanoma is a fatal form of skin cancer that carries a grave prognosis if the cancer cells spread and form metastases. The Kynurenine (Kyn) pathway is activated by the enzyme indoleamine 2,3-dioxygenase 1 (IDO-1) and has been shown to have a role in tumour progression. We have previously shown that interferon-γ (IFN-γ) acts as an inducer of tryptophan (Trp) degradation to Kyn in keratinocytes of the basal layer in a 3D epidermis model. Before extending our reconstructed human epidermis model to not only contain keratinocytes but also fibroblasts and melanocytes/melanoma cells, we have in this study set out to investigate possible differences between primary adult melanocytes and six melanoma cell lines regarding the expression of the immune checkpoint inhibitors IDO-1 and programmed death ligand 1 (PD-L1) together with Kyn production. MethodsThe melanocytes and melanoma cells were stimulated with 1–20 ng/ml of IFN-γ and the levels of Trp to Kyn degradation were monitored with high-performance liquid chromatography (HPLC). To analyze the viability of the cell types after IFN-γ treatment, an MTT assay was performed. mRNA quantity of IDO-1, PD-L1 and IFN-γ receptor (IFN-GR1) was analyzed with qPCR. ResultsAfter 24 h, only the metastatic cell line WM-266-4 was affected by all concentrations of IFN-γ, whereas at 48 h, the higher IFN-γ concentrations gave a more pronounced effect on the viability in all cell types. Trp was detected at various levels in the culture medium from all cell types before and after IFN-γ treatment. The degradation to Kyn was detected in primary melanocytes, Mel Juso, and Mel Ho cell lines after 24 h of treatment and low levels of IFN-γ. However, the higher concentration of IFN-γ, 20 ng/ml, induced Kyn to various degrees in all cell types after 24 h. The change in mRNA quantity of IDO-1 and PD-L1 was similar in all cell types. ConclusionTo conclude, no significant difference in upregulation of the immune checkpoint inhibitors PD-L1 and IDO-1 was seen between primary tumour and metastatic melanoma. IFN-γ stimulation of melanocytes and different stages of melanoma cell lines resulted in an increased Kyn/Trp ratio in the more aggressive melanoma cells when a high concentration was used (20 ng/ml) but when a lower concentration of IFN-γ (5 ng/ml) was used an increased Kyn/Trp ratio were detected in media from primary melanocytes and early-stage melanoma.

IL-1β mediates the induction of immune checkpoint regulators IDO1 and PD-L1 in lung adenocarcinoma cells

IntroductionInflammation plays a significant role in various cancers, including lung cancer, where the inflammatory cytokine IL-1β is often elevated in the tumor microenvironment. Patients with lung adenocarcinoma show higher levels of serum IL-1β compared to healthy individual. Moreover, IL-1β blockade reduces the incidence and mortality of lung cancer. Our prior studies revealed that alveolar type-II cells, the precursors for lung adenocarcinoma, display an induction in the expression of the enzyme tryptophan 2,3-dioxygenase (TDO2) during normal lung development. This induction of TDO2 coincides with an increase in IL-1β levels and is likely caused by IL-1β. Given that cancer cells can co-opt developmentally regulated pathways, we hypothesized that IL-1β may exert its pro-tumoral function by stimulating TDO2 and indoleamine 2, 3-dioxygenase-1 (IDO1), parallel enzymes involved in the conversion of tryptophan (Trp) into the immune-suppressive oncometabolite kynurenine (Kyn). Our goal was to determine whether IL-1β is a common upstream regulator of immune checkpoint regulators.MethodsTo determine whether IL-1β regulates IDO1, TDO2, PD-L1, and PD-L2, we measured mRNA and protein levels in lung adenocarcinoma cells lines (A549, H1792, H1838, H2347, H2228, HCC364 and HCC827) grown in 2D or 3D and in immortalized normal lung epithelial cells (HBEC3-KT and HSAEC1-KT). To determine the importance of the NFκB pathway in mediating IL-1β -regulated cellular effects, we used siRNA to knockdown RelA/p65 in IL-1β treated cells. The levels of Trp and Kyn in the IL-1β-treated cells and media were measured by mass spectrometry.ResultsUpon IL-1β stimulation, lung adenocarcinoma cells exhibited significant increases in IDO1 mRNA and protein levels, a response that depended on the NFκB pathway. Interestingly, this induction was more pronounced in 3D spheroid cultures compared to monolayer cultures and was not observed in normal immortalized lung epithelial cells. Furthermore, the conversion of Trp to Kyn increased in cells exposed to IL-1β, aligning with the heightened IDO1 expression. Remarkably, IL-1β also upregulated the expression of programmed death ligand-1 (PD-L1) and PD-L2 in multiple cell lines, indicating that IL-1β triggers parallel immune-suppressive mechanisms in lung adenocarcinoma cells.ConclusionsOur studies demonstrate that lung adenocarcinoma cells, but not normal immortalized lung epithelial cells, respond to IL-1β signaling by inducing the expression of parallel immune checkpoint proteins that have the potential to promote immune evasion.AWNWNjEXZEagXxNY6iY8VPVideo