Tryptophan metabolites regulate a variety of physiological processes, and their downstream metabolites enter the kynurenine pathway. Age-related changes of metabolites and activities of associated enzymes in this pathway are suggestable and would be potential intervention targets. Blood levels of serum tryptophan metabolites in C57BL/6 mice of different ages, ranging from 6 weeks to 10 months, were assessed using high-performance liquid chromatography, and the enzyme activities for each metabolic step were estimated using the ratio of appropriate metabolite levels. Mice were subjected to voluntary chronic aerobic exercise or high-fat diet to assess their ability to rescue age-related alterations in the kynurenine pathway. The ratio of serum kynurenic acid (KYNA) to 3-hydroxylkynurenine (3-HK) decreased with advancing age. Voluntary chronic aerobic exercise and high-fat diet rescued the decreased KYNA/3-HK ratio in the 6-month-old and 8-month-old mice groups. Tryptophan metabolites and their associated enzyme activities were significantly altered during aging, and the KYNA/3-HK ratio was a meaningful indicator of aging. Exercise and high-fat diet could potentially recover the reduction of the KYNA/3-HK ratio in the elderly.
Aged ; Aging ; Animals ; Chromatography, Liquid ; Diet, High-Fat* ; Exercise* ; Humans ; Infant ; Kynurenic Acid ; Kynurenine* ; Mice ; Physiological Processes ; Tryptophan*

The present study was designed to investigate the effect Hypericum Perforatum (HP), on behavioral changes, corticosterone, TNF-alpha levels and tryptophan metabolism and disposition in bilateral ovariectomized rats compared to 17alpha -ethinylestradiol. Behavioral analysis by measuring immobility time in forced swimming test and open field test, serum and hippocampal corticosterone and TNF-alpha along with hippocampal kynurenine/tryptophan ratio were determined in mature ovariectomized rats treated orally either by HP at three different doses 125, 250, and 500 mg/kg/day or by 17alpha-ethinylestradiol 30 microg/kg/day for 30 days. Ovariectomized rats showed significant increase in immobility time in the forced swimming test. Along with elevation in serum and hippocampal TNF-alpha and corticosterone levels associated with significant increase in hippocampal kynurenine/tryptophan ratio. Immobility time in the forced swimming test was decreased in rats treated by different doses of HP in a dose dependent manner and 17alpha-ethinylestradiol with no concomitant changes in the open field test. Only Rats treated with HP exhibited significant decrease in the elevated serum and hippocampal TNF-alpha and corticosterone, which couldn't explain the associated insignificant effect on hippocampaus kynurenine/tryptophan ratio in comparison to ovariectomized untreated rats. It is concluded that increased tryptophan metabolism toward kynurenine secondary to elevated corticosterone and TNF-alpha might be one of the pathohphysiological mechanisms that could explain depression like state observed in this rat model. Further, the observed attenuating effect of HP on TNF-alpha and corticosterone could contribute in its antidepressant effect in this animal model by other ways than their effects on tryptophan-kynurenine metabolism pathway.
Animals ; Corticosterone* ; Depression ; Hippocampus* ; Hypericum* ; Kynurenine ; Metabolism ; Models, Animal ; Physical Exertion ; Rats* ; Tryptophan ; Tumor Necrosis Factor-alpha*

OBJECTIVETo explore the differences of metabolic footprint in the conditioned culture medium of placental explants between early-onset and late-onset severe preeclampsia.

METHODSIn 13 cases of early-onset severe preeclampsia and 14 cases of late-onset severe preeclampsia, the placentas were sampled at the surface of the maternal placenta. High performance liquid chromatography-mass spectrometry (HPLC-MS) was used to determine the differences in the metabolites in the conditioned culture medium of the placental villous explants cultured in 6% atmospheric O(2) for 96 h. Standard samples were used to establish the tryptophan and kynurenine chromatography library by HPLC-MS to analyze the concentration of tryptophan and kynurenine in the conditioned culture medium.

RESULTSThirty-six metabolites showed statistically significant differences between early-onset and late-onset severe preeclampsia (P<0.05). The concentration of kynurenine was significantly higher in early-onset severe preeclampsia than in late-onset severe preeclampsia (P<0.05).

CONCLUSIONEarly-onset and late-onset severe preeclampsia may have different pathogeneses. By detecting the concentration of metabolites, metabolomic strategies provide a new means for predicting the onset time of severe preeclampsia.

Chorionic Villi ; metabolism ; Culture Media, Conditioned ; chemistry ; Female ; Humans ; In Vitro Techniques ; Kynurenine ; metabolism ; Ornithine ; metabolism ; Placenta ; metabolism ; Pre-Eclampsia ; metabolism ; Pregnancy ; Tryptophan ; metabolism

BACKGROUND/AIMS: Patients with irritable bowel syndrome (IBS) often report poor sleep quality. Whether poor sleep is associated with tryptophan (Trp) metabolites is unknown. We compared serum Trp metabolites in women with IBS and healthy controls (HCs) using targeted liquid chromatography mass spectrometry (LC-MS)-based profiling. In IBS only, we explored whether Trp metabolites are associated with IBS symptoms and subjective and objective sleep indices, serum cortisol, plasma adrenocorticotropic hormone (ACTH), and cortisol/ACTH levels. METHODS: Blood samples were obtained every 80 minutes in 21 HCs and 38 IBS subjects following an anticipation-of-public-speaking stressor during a sleep laboratory protocol. Subjects completed symptom diaries for 28 days. Adjacent values of metabolites were averaged to represent 4 time-periods: awake, early sleep, mid-sleep, and mid-to-late sleep. Thirteen of 20 targeted Trp metabolites were identified. RESULTS: Ten of 13 Trp metabolites decreased across the night, while nicotinamide increased in both groups. A MANOVA omnibus test performed after principal component analysis showed a significant difference in these 13 principal component (P = 0.014) between groups. Compared to HCs, nicotinamide levels were higher and indole-3-lactic acid levels lower in the IBS group. Melatonin and indole-3-acetic acid levels were associated with several subjective/objective sleep measures; decreased stool consistency/frequency and abdominal pain were positively associated with melatonin and serotonin in the IBS group. The kynurenine and kynurenic acid were associated with ACTH (positively) and cortisol/ACTH (negatively). CONCLUSIONS: Nighttime Trp metabolites may provide clues to poor sleep and stress with IBS. Further study of the mechanism of metabolite action is warranted.
Abdominal Pain ; Adrenocorticotropic Hormone ; Chromatography, Liquid ; Female ; Humans ; Hydrocortisone ; Irritable Bowel Syndrome ; Kynurenic Acid ; Kynurenine ; Mass Spectrometry ; Melatonin ; Niacinamide ; Plasma ; Principal Component Analysis ; Serotonin ; Tryptophan

To explore the correlation between kynurenine (KYN) metabolites and postpartum depression (PPD), and to provide new possible explanation for the pathogenesis of postpartum depression (PPD).
 Methods: A total of 726 Chinese women, who received cesarean section, were enrolled in this study. PPD was diagnosed with an Edinburgh Postnatal Depression Scale (EPDS) score ≥13. Twenty-four women with PPD and 48 matched women without PPD were randomly selected. The perinatal serum concentrations of KYN, quinolinic acid (QUIN) and kynurenic acid (KYNA) were measured. Subsequently, the puerperants were compared for the differences in the serum concentrations of KYN, QUIN and KYNA at the end of term, day 1 and day 3 after cesarean section, respectively.
 Results: The incidence of PPD was 7.99%. Of clinical characteristics, pressure during pregnancy was significantly different between subjects with or without PPD (P<0.01). Patients with PPD showed significantly increased serum KYN concentration (P<0.05) at the end of term, increased serum QUIN concentration (P<0.05) and decreased KYNA concentration (P<0.05) on the third day after cesarean section as compared with the control women. Furthermore, the KYNA/QUIN ratio was significantly higher in patients with PPD as compared to the control women on the third day after cesarean section (P<0.01).
 Conclusion: The contribution of alterations in plasma levels of KYN, QUIN and KYNA is closely related with the incidence of PPD, and correction of KYNA/QUIN ratio could be a new strategy for the prevention and treatment of postpartum depressive symptoms.
Biomarkers ; blood ; Cesarean Section ; psychology ; China ; epidemiology ; Depression, Postpartum ; blood ; epidemiology ; Female ; Humans ; Incidence ; Kynurenic Acid ; blood ; Kynurenine ; blood ; Pregnancy ; Quinolinic Acid ; blood

Cancer metabolism as a field of research was founded almost 100 years ago by Otto Warburg, who described the propensity for cancers to convert glucose to lactate despite the presence of oxygen, which in yeast diminishes glycolytic metabolism known as the Pasteur effect. In the past 20 years, the resurgence of interest in cancer metabolism provided significant insights into processes involved in maintenance metabolism of non-proliferating cells and proliferative metabolism, which is regulated by proto-oncogenes and tumor suppressors in normal proliferating cells. In cancer cells, depending on the driving oncogenic event, metabolism is re-wired for nutrient import, redox homeostasis, protein quality control, and biosynthesis to support cell growth and division. In general, resting cells rely on oxidative metabolism, while proliferating cells rewire metabolism toward glycolysis, which favors many biosynthetic pathways for proliferation. Oncogenes such as MYC, BRAF, KRAS, and PI3K have been documented to rewire metabolism in favor of proliferation. These cell intrinsic mechanisms, however, are insufficient to drive tumorigenesis because immune surveillance continuously seeks to destroy neo-antigenic tumor cells. In this regard, evasion of cancer cells from immunity involves checkpoints that blunt cytotoxic T cells, which are also attenuated by the metabolic tumor microenvironment, which is rich in immuno-modulating metabolites such as lactate, 2-hydroxyglutarate, kynurenine, and the proton (low pH). As such, a full understanding of tumor metabolism requires an appreciation of the convergence of cancer cell intrinsic metabolism and that of the tumor microenvironment including stromal and immune cells.
Biosynthetic Pathways ; Carcinogenesis ; Glucose ; Glycolysis ; Homeostasis ; Kynurenine ; Lactic Acid ; Metabolism ; Oncogenes ; Oxidation-Reduction ; Oxygen ; Proto-Oncogenes ; Protons ; Quality Control ; T-Lymphocytes ; Tumor Microenvironment ; Yeasts

PURPOSE: Breast cancer has become a major public health threat in the current society. Anthracycline doxorubicin (DOX) is a widely used drug in breast cancer chemotherapy. We aimed to investigate the immunogenic death of breast tumor cells caused by DOX, and detect the effects of combination of DOX and a small molecule inhibitor in tumor engrafted mouse model. METHODS: We used 4T1 breast cancer cells to examine the anthracycline DOX-mediated immunogenic death of breast tumor cells by assessing the calreticulin exposure and adenosine triphosphate and high mobility group box 1 release. Using 4T1 tumor cell-engrafted mouse model, we also detected the expression of indoleamine 2,3-dioxygenase (IDO) in tumor tissues after DOX treatment and further explored whether the specific small molecule IDO1 inhibitor NLG919 combined with DOX, can exhibit better therapeutic effects on breast cancer. RESULTS: DOX induced immunogenic cell death of murine breast cancer cells 4T1 as well as the upregulation of IDO1. We also found that treatment with NLG919 enhanced kynurenine inhibition in a dose-dependent manner. IDO1 inhibition reversed CD8+ T cell suppression mediated by IDO-expressing 4T1 murine breast cancer cells. Compared to the single agent or control, combination of DOX and NLG919 significantly inhibited the tumor growth, indicating that the 2 drugs exhibit synergistic effect. The combination therapy also increased the expression of transforming growth factor-β, while lowering the expressions of interleukin-12p70 and interferon-γ. CONCLUSION: Compared to single agent therapy, combination of NLG919 with DOX demonstrated better therapeutic effects in 4T1 murine breast tumor model. IDO inhibition by NLG919 enhanced the therapeutic efficacy of DOX in breast cancer, achieving synergistic effect.
Adenosine Triphosphate ; Animals ; Breast Neoplasms ; Breast ; Calreticulin ; Cell Death ; Doxorubicin ; Drug Therapy ; Indoleamine-Pyrrole 2,3,-Dioxygenase ; Kynurenine ; Mice ; Public Health ; Therapeutic Uses ; Up-Regulation

BACKGROUND: Uteroglobin (UG) is a secretary protein that has strong immunomodulatory properties, and which is synthesized in most epithelia including lung tissue. Overexpression of UG is associated with decreased expression of cyclooxygenase (COX)-2 and suppression of cancer cell growth. Indoleamine 2,3-dioxygenase (IDO) catalyzes tryptophan along the kynurenine pathway, and both the reduction in local tryptophan and the production of tryptophan metabolites contribute to the immunosuppressive effects of IDO. METHODS: In this study, we investigated the pattern of expression of COX-2 and IDO, and the effect of UG transduction in the expression of COX-2 and IDO in several non-small cell lung cancer cell lines, especially A549. RESULTS: Both COX-2 and IDO were constitutionally expressed in A549 and H460 cells, and was reduced by UG transduction. In A549 cells, the slightly increased expression of COX-2 and IDO with the instillation of interferon-gamma (IFN-gamma) was reduced by UG transduction. However, the reduced expression of COX-2 and IDO by UG transduction was not increased with IFN-gamma instillation in A549 cells. In both the A549 COX-2 sense and the A549 COX-2 anti-sense small interfering RNA (siRNA)-transfected cells, IDO was expressed; expression was reduced by UG transduction, irrespective of the expression of COX-2. CONCLUSION: The results suggest that the anti-proliferative function of UG may be associated with the immune tolerance pathway of IDO, which is independent of the COX-2 pathway.
Carcinoma, Non-Small-Cell Lung ; Cell Line ; Constitution and Bylaws ; Cyclooxygenase 2 ; Immune Tolerance ; Indoleamine-Pyrrole 2,3,-Dioxygenase ; Interferon-gamma ; Kynurenine ; Lung ; Prostaglandin-Endoperoxide Synthases ; RNA, Small Interfering ; Tryptophan ; Uteroglobin

OBJECTIVETo investigate the immunological characteristics of human tonsil mesenchymal stem cells (TMSCs).

METHODSHuman tonsil tissues were obtained from the children patients with chronic tonsillitis. TMSCs were separated, cultured, and were detected the expression profiles of HLA-I, HLA-II, CD80, CD86 by flow cytometry. The measurement of immunogenicity, the effect on phytohemagglutinin (PHA) induced peripheral blood mononuclear cell (PBMCs) proliferation and mixed lymphocytes reaction (MLR) were performed to identify the immunological characteristics of TMSCs. The co-cultures of TMSCs + PBMCs + PHA and TMSCs + MLR were established, respectively, and the concentration of kynurenine, which is the metabolin of indoleamine 2, 3-dioxygenase, in the culture supernatant were examined. Then we added 1-methyl-L-tryptophan into the co-culture of TMSCs + PBMCs + PHA and TMSCs + MLR, respectively, and tested the proliferation of PBMCs. Each experiment was repeated three times, and there were six samples in each group. Statistical significance was assessed by analysis of variance (ANOVA), and a P value less than 0.05 was considered statistically significant.

RESULTSTMSCs expressed HLA-I, were negative for HLA-II and co-stimulatory molecules CD80 and CD86. The stimulation index in the group of TMSCs + allogeneic PBMCs was 1.38 ± 0.26, whereas the stimulation index in the group of allogeneic PBMCs was 1.22 ± 0.28, and there was no significant difference between the two groups (P > 0.05), indicating that TMSCs could not initiate the proliferation of allogeneic PBMCs. The stimulation indexes in the group of TMSCs + allogeneic PBMCs + PHA were 1.49 ± 0.29 and 1.23 ± 0.22, respectively, whereas the stimulation index in the group of allogeneic PBMCs + PHA was 4.60 ± 0.81, and the difference between the two groups had a statistical significance (P < 0.05) suggesting that TMSCs could inhibit PHA-induced PBMCs proliferation. The stimulation indexes in the group of TMSCs + MLR were 1.29 ± 0.23 and 1.26 ± 0.27, respectively, however, the stimulation index in the group of MLR was 3.04 ± 0.66, and the difference between the two groups had a statistical significance (P < 0.05), demonstrating that TMSCs could suppress MLR-induced PBMCs proliferation. The levels of kynurenine were (26.0 ± 2.3) μmol/L and (23.5 ± 4.5) μmol/L in the culture of TMSCs + PBMCs + PHA and TMSCs + MLR, respectively, thus elevating significantly. After adding of 1-methyl-L-tryptophan, TMSCs-mediated-proliferation suppression of PBMCs restored to normal levels.

CONCLUSIONTMSCs possess low immunogenecity and immunosuppressive function, may be used in allogeneic transplantation.

Cell Proliferation ; Cells, Cultured ; Child ; Coculture Techniques ; Flow Cytometry ; Humans ; Immunosuppression ; Kynurenine ; analysis ; Leukocytes, Mononuclear ; Lymphocyte Culture Test, Mixed ; methods ; Mesenchymal Stromal Cells ; cytology ; immunology ; Palatine Tonsil ; cytology ; Tryptophan ; administration & dosage ; analogs & derivatives

A growing body of evidence suggests that major depression is associated with increased productions of pro-inflammatory cytokines such as IL-1, IL-6, IL-12 or TNF-alpha and increased concentrations of prostaglandin E2 and negative-regulatory cytokines such as IL-4 or IL-10. In major depression, interactions among brain 5-HT levels, the activity of its autoreceptors, and that of postsynaptic receptors play a critical role in mood changes and depression. Recently, the link between cytokines and serotonergic turnover has been explored. Cytokines such as IL-1, IL-2 and IFN-gamma reduce the production of 5-HT by stimulating the activity of indoleamine-2,3 dioxygenase (IDO), an enzyme which convert tryptophan, the precursor of 5-HT to kynurenine. The kynurenine is metabolized into quinolinic acid (quinolinate) and kynurenic acid (kynurenate), an excitotoxic NMDA receptor agonist and the antagonist of three ionotropic excitotatory aminoacid receptors, respectively. The cytokineserotonin interaction through IDO that leads to the challenge between quinolinate and kynurenate in the brain may finally induce the neurodegeneration in depression. The neurodegeneration hypothesis of depression can explain how people cope with psychological or physical stress at different stages according to severity and duration of stress and why major depression develops.
Autoreceptors ; Brain ; Cytokines ; Depression* ; Dinoprostone ; Interleukin-1 ; Interleukin-10 ; Interleukin-12 ; Interleukin-2 ; Interleukin-4 ; Interleukin-6 ; Kynurenic Acid ; Kynurenine ; N-Methylaspartate ; Neurogenesis ; Quinolinic Acid ; Serotonin ; Tryptophan ; Tumor Necrosis Factor-alpha