Clustered de novo start-loss variants in GLUL result in a developmental and epileptic encephalopathy via stabilization of glutamine synthetase.

Glutamine synthetase (GS), encoded by GLUL, catalyzes the conversion of glutamate to glutamine. GS is pivotal for the generation of the neurotransmitters glutamate and gamma-aminobutyric acid and is the primary mechanism of ammonia detoxification in the brain. GS levels are regulated post-translationally by an N-terminal degron that enables the ubiquitin-mediated degradation of GS in a glutamine-induced manner. GS deficiency in humans is known to lead to neurological defects and death in infancy, yet how dysregulation of the degron-mediated control of GS levels might affect neurodevelopment is unknown. We ascertained nine individuals with severe developmental delay, seizures, and white matter abnormalities but normal plasma and cerebrospinal fluid biochemistry with de novo variants in GLUL. Seven out of nine were start-loss variants and two out of nine disrupted 5' UTR splicing resulting in splice exclusion of the initiation codon. Using transfection-based expression systems and mass spectrometry, these variants were shown to lead to translation initiation of GS from methionine 18, downstream of the N-terminal degron motif, resulting in a protein that is stable and enzymatically competent but insensitive to negative feedback by glutamine. Analysis of human single-cell transcriptomes demonstrated that GLUL is widely expressed in neuro- and glial-progenitor cells and mature astrocytes but not in post-mitotic neurons. One individual with a start-loss GLUL variant demonstrated periventricular nodular heterotopia, a neuronal migration disorder, yet overexpression of stabilized GS in mice using in utero electroporation demonstrated no migratory deficits. These findings underline the importance of tight regulation of glutamine metabolism during neurodevelopment in humans.

The efficacy of Carbamylglutamate impacts the nutritional management of patients with N-Acetylglutamate synthase deficiency.

BACKGROUND: The autosomal recessive disorder N-acetylglutamate synthase (NAGS) deficiency is the rarest defect of the urea cycle, with an incidence of less than one in 2,000,000 live births. Hyperammonemic crises can be avoided in individuals with NAGS deficiency by the administration of carbamylglutamate (also known as carglumic acid), which activates carbamoyl phosphatase synthetase 1 (CPS1). The aim of this case series was to introduce additional cases of NAGS deficiency to the literature as well as to assess the role of nutrition management in conjunction with carbamylglutamate therapy across new and existing cases. METHODS: We conducted retrospective chart reviews of seven cases of NAGS deficiency in the US and Canada, focusing on presentation, diagnosis, medication management, nutrition management, and outcomes. RESULTS: Five new and two previously published cases were included. Presenting symptoms were consistent with previous reports. Diagnostic confirmation via molecular testing varied in protocol across cases, with consecutive single gene tests leading to long delays in diagnosis in some cases. All patients responded well to carbamylglutamate therapy, as indicated by normalization of plasma ammonia and citrulline, as well as urine orotic acid in patients with abnormal levels at baseline. Although protein restriction was not prescribed in any cases after carbamylglutamate initiation, two patients continued to self-restrict protein intake. One patient experienced two episodes of hyperammonemia that resulted in poor long-term outcomes. Both episodes occurred after a disruption in access to carbamylglutamate, once due to insurance prior authorization requirements and language barriers and once due to seizure activity limiting the family's ability to administer carbamylglutamate. CONCLUSIONS: Follow-up of patients with NAGS deficiency should include plans for illness and for disruption of carbamylglutamate access, including nutrition management strategies such as protein restriction. Carbamylglutamate can help patients with NAGS deficiency to liberalize their diets, but the maximum safe level of protein intake to prevent hyperammonemia is not yet known. Patients using this medication should still monitor their diet closely and be prepared for any disruptions in medication access, which might require immediate dietary adjustments or medical intervention to prevent hyperammonemia.

Brain-derived neurotrophic factor scales presynaptic calcium transients to modulate excitatory neurotransmission.

Brain-derived neurotrophic factor (BDNF) plays a critical role in synaptic physiology, as well as mechanisms underlying various neuropsychiatric diseases and their treatment. Despite its clear physiological role and disease relevance, BDNF's function at the presynaptic terminal, a fundamental unit of neurotransmission, remains poorly understood. In this study, we evaluated single synapse dynamics using optical imaging techniques in hippocampal cell cultures. We find that exogenous BDNF selectively increases evoked excitatory neurotransmission without affecting spontaneous neurotransmission. However, acutely blocking endogenous BDNF has no effect on evoked or spontaneous release, demonstrating that different approaches to studying BDNF may yield different results. When we suppressed BDNF-Tropomyosin receptor kinase B (TrkB) activity chronically over a period of days to weeks using a mouse line enabling conditional knockout of TrkB, we found that evoked glutamate release was significantly decreased while spontaneous release remained unchanged. Moreover, chronic blockade of BDNF-TrkB activity selectively downscales evoked calcium transients without affecting spontaneous calcium events. Via pharmacological blockade by voltage-gated calcium channel (VGCC) selective blockers, we found that the changes in evoked calcium transients are mediated by the P/Q subtype of VGCCs. These results suggest that BDNF-TrkB activity increases presynaptic VGCC activity to selectively increase evoked glutamate release.

Structural bioinformatics studies of glutamate transporters and their AlphaFold2 predicted water-soluble QTY variants and uncovering the natural mutations of L->Q, I->T, F->Y and Q->L, T->I and Y->F.

Glutamate transporters play key roles in nervous physiology by modulating excitatory neurotransmitter levels, when malfunctioning, involving in a wide range of neurological and physiological disorders. However, integral transmembrane proteins including the glutamate transporters remain notoriously difficult to study, due to their localization within the cell membrane. Here we present the structural bioinformatics studies of glutamate transporters and their water-soluble variants generated through QTY-code, a protein design strategy based on systematic amino acid substitutions. These include 2 structures determined by X-ray crystallography, cryo-EM, and 6 predicted by AlphaFold2, and their predicted water-soluble QTY variants. In the native structures of glutamate transporters, transmembrane helices contain hydrophobic amino acids such as leucine (L), isoleucine (I), and phenylalanine (F). To design water-soluble variants, these hydrophobic amino acids are systematically replaced by hydrophilic amino acids, namely glutamine (Q), threonine (T) and tyrosine (Y). The QTY variants exhibited water-solubility, with four having identical isoelectric focusing points (pI) and the other four having very similar pI. We present the superposed structures of the native glutamate transporters and their water-soluble QTY variants. The superposed structures displayed remarkable similarity with RMSD 0.528Å-2.456Å, despite significant protein transmembrane sequence differences (41.1%->53.8%). Additionally, we examined the differences of hydrophobicity patches between the native glutamate transporters and their QTY variants. Upon closer inspection, we discovered multiple natural variations of L->Q, I->T, F->Y and Q->L, T->I, Y->F in these transporters. Some of these natural variations were benign and the remaining were reported in specific neurological disorders. We further investigated the characteristics of hydrophobic to hydrophilic substitutions in glutamate transporters, utilizing variant analysis and evolutionary profiling. Our structural bioinformatics studies not only provided insight into the differences between the hydrophobic helices and hydrophilic helices in the glutamate transporters, but they are also expected to stimulate further study of other water-soluble transmembrane proteins.

Glutamate Signaling in Patients With Parkinson Disease With REM Sleep Behavior Disorder.

BACKGROUND AND OBJECTIVES: Clinical heterogeneity of patients with Parkinson disease (PD) is well recognized. PD with REM sleep behavior disorder (RBD) is a more malignant phenotype with faster motor progression and higher nonmotor symptom burden. However, the neural mechanisms underlying this clinical divergence concerning imbalances in neurotransmitter systems remain elusive. METHODS: Combining magnetic resonance (MR) spectroscopy and [11C]ABP688 PET on a PET/MR hybrid system, we simultaneously investigated two different mechanisms of glutamate signaling in patients with PD. Patients were grouped according to their RBD status in overnight video-polysomnography and compared with age-matched and sex-matched healthy control (HC) participants. Total volumes of distribution (VT) of [11C]ABP688 were estimated with metabolite-corrected plasma concentrations during steady-state conditions between 45 and 60 minutes of the scan following a bolus-infusion protocol. Glutamate, glutamine, and glutathione levels were investigated with single-voxel stimulated echo acquisition mode MR spectroscopy of the left basal ganglia. RESULTS: We measured globally elevated VT of [11C]ABP688 in 16 patients with PD and RBD compared with 17 patients without RBD and 15 HC participants (F(2,45) = 5.579, p = 0.007). Conversely, glutamatergic metabolites did not differ between groups and did not correlate with the regional VT of [11C]ABP688. VT of [11C]ABP688 correlated with the amount of REM sleep without atonia (F(1,42) = 5.600, p = 0.023) and with dopaminergic treatment response in patients with PD (F(1,30) = 5.823, p = 0.022). DISCUSSION: Our results suggest that patients with PD and RBD exhibit altered glutamatergic signaling indicated by higher VT of [11C]ABP688 despite unaffected glutamate levels. The imbalance of glutamate receptors and MR spectroscopy glutamate metabolite levels indicates a novel mechanism contributing to the heterogeneity of PD and warrants further investigation of drugs targeting mGluR5.

Investigating the impact of Psidium guajava leaf hydroalcoholic extract in improving glutamatergic toxicity-induced oxidative stress in Danio rerio larvae.

Glutamate is one of the predominant excitatory neurotransmitters released from the central nervous system; however, at high concentrations, this substance may induce excitotoxicity. This phenomenon is involved in numerous neuropathologies. At present, clinically available pharmacotherapeutic agents to counteract glutamatergic excitotoxicity are not completely effective; therefore, research to develop novel compounds is necessary. In this study, the main objective was to determine the pharmacotherapeutic potential of the hydroalcoholic extract of Psidium guajava (PG) in a model of oxidative stress-induced by exposure to glutamate utilizing Danio rerio larvae (zebrafish) as a model. Data showed that treatment with glutamate produced a significant increase in oxidative stress, chromatin damage, apoptosis, and locomotor dysfunction. All these effects were attenuated by pre-treatment with the classical antioxidant N-acetylcysteine (NAC). Treatment with PG inhibited oxidative stress responsible for cellular damage induced by glutamate. However, exposure to PG failed to prevent glutamate-initiated locomotor damage. Our findings suggest that under conditions of oxidative stress, PG can be considered as a promising candidate for treatment of glutamatergic excitotoxicity and consequent neurodegenerative diseases.

The metabolic reprogramming of γ-aminobutyrate in oral squamous cell carcinoma.

Oral squamous cell carcinoma (OSCC) is the most common head and neck malignancy. The oncometabolites have been studied in OSCC, but the mechanism of metabolic reprogramming remains unclear. To identify the potential metabolic markers to distinguish malignant oral squamous cell carcinoma (OSCC) tissue from adjacent healthy tissue and study the mechanism of metabolic reprogramming in OSCC. We compared the metabolites between cancerous and paracancerous tissues of OSCC patients by 1HNMR analysis. We established OSCC derived cell lines and analyzed their difference of RNA expression by RNA sequencing. We investigated the metabolism of γ-aminobutyrate in OSCC derived cells by real time PCR and western blotting. Our data revealed that much more γ-aminobutyrate was produced in cancerous tissues of OSCC patients. The investigation based on OSCC derived cells showed that the increase of γ-aminobutyrate was promoted by the synthesis of glutamate beyond the mitochondria. In OSCC cancerous tissue derived cells, the glutamate was catalyzed to glutamine by glutamine synthetase (GLUL), and then the generated glutamine was metabolized to glutamate by glutaminase (GLS). Finally, the glutamate produced by glutamate-glutamine-glutamate cycle was converted to γ-aminobutyrate by glutamate decarboxylase 2 (GAD2). Our study is not only benefit for understanding the pathological mechanisms of OSCC, but also has application prospects for the diagnosis of OSCC.

Pharmacokinetics of L-theanine and the effect on amino acid composition in mice administered with L-theanine.

L-theanine, an amino acid component of the tea leaves of Camellia sinensis, is sold in Japan as a supplement for good sleep. Although several studies in humans and mice have reported the effects of L-theanine on brain function, only a few reports have comprehensively clarified the disposition of theanine administered to mice and its effects on concentrations of other blood amino acids. In this study, we aimed to determine the changes in the blood levels of L-theanine administered to mice and amino acid composition of the serum. L-theanine were administered to four-week-old Std-ddY male mice orally or via tail vein injection. L-theanine and other amino acids in serum prepared from blood collected at different time points post-dose were labeled with phenylisothiocyanate and quantified. The serum concentration of orally administered L-theanine peaked 15 min after administration. The area under the curve for tail vein injection revealed the bioavailability of L- theanine to be approximately 70%. L-theanine administration did not affect any amino acid levels in the serum, but a significant increase in the peak area overlapping the Glycine (Gly) peak was observed 30 min after administration. L-theanine administered to mice was rapidly absorbed and eliminated, suggesting that taking L-theanine as a supplement is safe without affecting its own levels or serum levels of other amino acids. However, considering that Gly, similar to L-theanine, is used as a dietary supplement for its anxiolytic effects and to improve sleep, determining the effects of L-theanine administration on Gly is important and needs further research.

l-Theanine Prevents Colonic Damage via NF-κB/MAPK Signaling Pathways Induced by a High-Fat Diet in Rats.

SCOPE: l-Theanine (l-Thea) is an amino acid which is naturally present in tea leaves. It has been associated with possible health advantages, including obesity prevention, but the underlying molecular mechanisms have not been elucidated. METHODS AND RESULTS: A multiomics approach is utilized to examine the mechanism by which l-Thea exerts its antiobesity effects. This study reveals that l-Thea administration significantly ameliorates high-fat diet (HFD)-induced obesity in rats by improving body weight and hyperlipidemia. l-Thea mitigates HFD-induced inflammation and reverses hepatic and colonic damage, and intestinal barrier. This research verifies that the preventive effect of l-Thea on obesity in rats induced by an HFD with colitis is accomplished by suppressing the phosphorylation of important proteins in the NF-κB/mitogen-activated protein kinase (MAPK) pathways. Metabolome analysis reveals that l-Thea regulates HFD-induced metabolic disorders, specifically through modulation of steroid hormone biosynthesis. Microbiome analysis reveals that l-Thea mitigates HFD-induced dysbiosis by increasing the relative abundance of obesity-associated probiotic bacteria, including Blautia coccoides and Lactobacillus murinus, while simultaneously suppressing the abundance of pathogenic bacteria. CONCLUSIONS: l-Thea alleviates colitis generated by an HFD by restoring the integrity of the intestinal barrier, suppressing inflammation through regulation of MAPK/NF-κB signaling pathways, and enhancing microbial metabolism in colon.

Experimentally evolved Staphylococcus aureus shows increased survival in the presence of Pseudomonas aeruginosa by acquiring mutations in the amino acid transporter, GltT.

When cultured together under standard laboratory conditions Pseudomonas aeruginosa has been shown to be an effective inhibitor of Staphylococcus aureus. However, P. aeruginosa and S. aureus are commonly observed in coinfections of individuals with cystic fibrosis (CF) and in chronic wounds. Previous work from our group revealed that S. aureus isolates from CF infections are able to persist in the presence of P. aeruginosa strain PAO1 with a range of tolerances with some isolates being eliminated entirely and others maintaining large populations. In this study, we designed a serial transfer, evolution experiment to identify mutations that allow S. aureus to survive in the presence of P. aeruginosa. Using S. aureus USA300 JE2 as our ancestral strain, populations of S. aureus were repeatedly cocultured with fresh P. aeruginosa PAO1. After eight coculture periods, S. aureus populations that survived better in the presence of PAO1 were observed. We found two independent mutations in the highly conserved S. aureus aspartate transporter, gltT, that were unique to evolved P. aeruginosa-tolerant isolates. Subsequent phenotypic testing demonstrated that gltT mutants have reduced uptake of glutamate and outcompeted wild-type S. aureus when glutamate was absent from chemically defined media. These findings together demonstrate that the presence of P. aeruginosa exerts selective pressure on S. aureus to alter its uptake and metabolism of key amino acids when the two are cultured together.

Synthesis and Macrodomain Binding of Gln-carba-ADPr-peptide.

Mono-ADP-ribosylation is a dynamic post-translational modification (PTM) with important roles in cell signalling. This modification occurs on a wide variety of amino acids, and one of the canonical modification sites within proteins is the side chain of glutamic acid. Given the transient nature of this modification (acylal linkage) and the high sensitivity of ADP-ribosylated glutamic acid, stabilized isosteres are required for structural and biochemical studies. Here, we report the synthesis of a mimic of ADP-ribosylated peptide derived from histone H2B that contains carba-ADP-ribosylated glutamine as a potential mimic for Glu-ADPr. We synthesized a cyclopentitol-ribofuranosyl derivative of 5'-phosphoribosylated Fmoc-glutamine and used this in the solid-phase synthesis of the carba-ADPr-peptide mimicking the ADP-ribosylated N-terminal tail of histone H2B. Binding studies with isothermal calorimetry demonstrate that the macrodomains of human MacroD2 and TARG1 bind to carba-ADPr-peptide in the same way as ADPr-peptides containing the native ADP-riboside moiety connected to the side chain of glutamine in the same peptide sequence.

Repeatability of deuterium metabolic imaging of healthy volunteers at 3 T.

BACKGROUND: Magnetic resonance (MR) imaging of deuterated glucose, termed deuterium metabolic imaging (DMI), is emerging as a biomarker of pathway-specific glucose metabolism in tumors. DMI is being studied as a useful marker of treatment response in a scan-rescan scenario. This study aims to evaluate the repeatability of brain DMI. METHODS: A repeatability study was performed in healthy volunteers from December 2022 to March 2023. The participants consumed 75 g of [6,6'-2H2]glucose. The delivery of 2H-glucose to the brain and its conversion to 2H-glutamine + glutamate, 2H-lactate, and 2H-water DMI was imaged at baseline and at 30, 70, and 120 min. DMI was performed using MR spectroscopic imaging on a 3-T system equipped with a 1H/2H-tuned head coil. Coefficients of variation (CoV) were computed for estimation of repeatability and between-subject variability. In a set of exploratory analyses, the variability effects of region, processing, and normalization were estimated. RESULTS: Six male participants were recruited, aged 34 ± 6.5 years (mean ± standard deviation). There was 42 ± 2.7 days between sessions. Whole-brain levels of glutamine + glutamate, lactate, and glucose increased to 3.22 ± 0.4 mM, 1.55 ± 0.3 mM, and 3 ± 0.7 mM, respectively. The best signal-to-noise ratio and repeatability was obtained at the 120-min timepoint. Here, the within-subject whole-brain CoVs were -10% for all metabolites, while the between-subject CoVs were -20%. CONCLUSIONS: DMI of glucose and its downstream metabolites is feasible and repeatable on a clinical 3 T system. TRIAL REGISTRATION: ClinicalTrials.gov, NCT05402566 , registered the 25th of May 2022. RELEVANCE STATEMENT: Brain deuterium metabolic imaging of healthy volunteers is repeatable and feasible at clinical field strengths, enabling the study of shifts in tumor metabolism associated with treatment response. KEY POINTS: • Deuterium metabolic imaging is an emerging tumor biomarker with unknown repeatability.  • The repeatability of deuterium metabolic imaging is on par with FDG-PET.  • The study of deuterium metabolic imaging in clinical populations is feasible.

Metabolic responses to the occurrence and chemotherapy of pancreatic cancer: biomarker identification and prognosis prediction.

As the most malignant tumor, the prognosis of pancreatic cancer is not ideal even in the small number of patients who can undergo radical surgery. As a highly heterogeneous tumor, chemotherapy resistance is a major factor leading to decreased efficacy and postoperative recurrence of pancreatic cancer. In this study, nuclear magnetic resonance (NMR)-based metabolomics was applied to identify serum metabolic characteristics of pancreatic ductal adenocarcinoma (PDAC) and screen the potential biomarkers for its diagnosis. Metabolic changes of patients with different CA19-9 levels during postoperative chemotherapy were also monitored and compared to identify the differential metabolites that may affect the efficacy of chemotherapy. Finally, 19 potential serum biomarkers were screened to serve the diagnosis of PDAC, and significant metabolic differences between the two CA19-9 stratifications of PDAC were involved in energy metabolism, lipid metabolism, amino acid metabolism, and citric acid metabolism. Enrichment analysis of metabolic pathways revealed six shared pathways by PDAC and chemotherapy such as alanine, aspartate and glutamate metabolism, arginine biosynthesis, glutamine and glutamate metabolism, citrate cycle, pyruvate metabolism, and glycogolysis/gluconeogeneis. The similarity between the metabolic characteristics of PDAC and the metabolic responses to chemotherapy provided a reference for clinical prediction of benefits of postoperative chemotherapy in PDAC patients.

Safety and efficacy of trofinetide in Rett syndrome: a systematic review and meta-analysis of randomized controlled trials.

INTRODUCTION: Rett syndrome is a rare genetic neurodevelopmental disorder that predominantly impacts females. It presents with loss of acquired skills, impaired communication, and stereotypic hand movements. Given the limited treatment options for Rett syndrome, there is a dire need for effective interventions. OBJECTIVE: To evaluate the safety and efficacy of trofinetide in Randomized Controlled Trials (RCTs) that report on Rett syndrome patients. METHODS: We identified 109 articles from four databases (Scopus, PubMed, Web of Science, and Cochrane CENTRAL). After removing the duplicates, we narrowed them down to 59 articles for further assessment. We included RCTs that evaluated the efficacy and safety of trofinetide in patients with Rett syndrome. Three studies were eligible for inclusion. Two independent reviewers evaluated the identified studies' titles, abstracts, and full texts, extracting pertinent data. We assessed the quality of the studies using the Cochrane Risk of Bias (RoB) 2.0 tool. We then conducted a meta-analysis using the fixed effects model in the case of insignificant heterogeneity; otherwise, we used the random effects model. Based on the nature of the outcome, we analyzed the mean difference or the odds ratio. Analysis was conducted using RevMan version 5.3. RESULTS: Among the analyzed outcomes in 181 patients in the trofinetide group and 134 patients in the placebo group, significant improvement in Rett Syndrome Behavior Questionnaire (RSBQ) scores was observed at 200 mg dosage (overall mean difference: -3.53, p = 0.001). Clinical Global Impression-Improvement (CGI-I) scores improved considerably at 200 mg dosage (overall mean difference: -0.34, p < 0.0001). No substantial changes were observed in Motor Behavioral Assessment (MBA) or Top 3 Caregiver Concerns. We evaluated Treatment Emergent Adverse Events (TEAEs) across the various dosages and noted significant associations with diarrhea (200 mg), vomiting (200 mg), and irritability (200 mg). However, we did not find a significant association between any of the dosages and the incidence of decreased appetite. CONCLUSION: Trofinetide demonstrated potential in improving RSBQ and CGI-I scores at 200 mg dosage. Although no substantial changes were found in MBA and top 3 caregiver concerns. Adverse events were linked to specific dosages.

Children with Hirschsprung disease exhibited alterations in host-microbial co-metabolism after pull-through operation.

PURPOSE: This study aims to compare the fecal metabolome in post pull-through HD with and without HAEC patients and healthy young children using nuclear magnetic resonance (NMR) spectroscopy. METHODS: Fresh fecal samples were collected from children under 5 years of age in both post-pull-through HD patients and healthy Thai children. A total of 20 fecal samples were then analyzed using NMR spectroscopy. RESULTS: Thirty-four metabolites identified among HD and healthy children younger than 5 years were compared. HD samples demonstrated a significant decrease in acetoin, phenylacetylglutamine, and N-acetylornithine (corrected p value = 0.01, 0.04, and 0.004, respectively). Succinate and xylose significantly decreased in HD with HAEC group compared to HD without HAEC group (corrected p value = 0.04 and 0.02, respectively). Moreover, glutamine and glutamate metabolism, and alanine, aspartate, and glutamate metabolism were the significant pathways involved, with pathway impact 0.42 and 0.50, respectively (corrected p value = 0.02 and 0.04, respectively). CONCLUSION: Differences in class, quantity, and metabolism of protein and other metabolites in young children with HD after pull-through operation were identified. Most of the associated metabolic pathways were correlated with the amino acids metabolism, which is required to maintain intestinal integrity and function.

Metabotropic Glutamate Receptor 4 (mGlu4) Positive Allosteric Modulators Lack Efficacy in Rat and Marmoset Models of L-DOPA-Induced Dyskinesia.

Background: Increased activity across corticostriatal glutamatergic synapses may contribute to L-DOPA-induced dyskinesia in Parkinson's disease. Given the weak efficacy and side-effect profile of amantadine, alternative strategies to reduce glutamate transmission are being investigated. Metabotropic glutamate receptor 4 (mGlu4) is a promising target since its activation would reduce glutamate release. Objective: We hypothesized that two mGlu4 positive allosteric modulators, Lu AF21934 ((1 S,2 R)-N1-(3,4-dichlorophenyl)cyclohexane-1,2-dicarboxamide) and ADX88178 (5-Methyl-N-(4-methylpyrimidin-2-yl)-4-(1H-pyrazol-4-yl)thiazol-2-amine), would provide relief in rat and primate models of L-DOPA-induced dyskinesia. Methods: The ability of Lu AF21934 or ADX88178 to reverse pre-established dyskinesia was examined in L-DOPA-primed 6-hydroxydopamine-lesioned rats expressing abnormal involuntary movements (AIMs) or in 1-methyl-4-phenyl,1,2,3,6-tetrahydropyridine (MPTP)-treated common marmosets expressing L-DOPA-induced dyskinesia. Additionally, the ability of Lu AF21934 to prevent the development of de novo L-DOPA-induced AIMs was explored in the 6-hydroxydopamine-lesioned rats. Results: Neither Lu AF21934 (10 or 30 mg/kg p.o.) nor ADX88178 (10 or 30 mg/kg p.o.) reduced pre-established AIMs in 6-hydroxydopamine-lesioned rats. Similarly, in L-DOPA-primed common marmosets, no reduction in established dyskinesia was observed with Lu AF21934 (3 or 10 mg/kg p.o.). Conversely, amantadine significantly reduced (>40%) the expression of dyskinesia in both models. Lu AF21934 also failed to suppress the development of AIMs in 6-hydroxydopamine-lesioned rats. Conclusions: This study found no benefit of mGlu4 positive allosteric modulators in tackling L-DOPA-induced dyskinesia. These findings are concordant with the recent failure of foliglurax in phase II clinical trials supporting the predictive validity of these pre-clinical dyskinesia models, while raising further doubt on the anti-dyskinetic potential of mGlu4 positive allosteric modulators.

Effect of sulfasalazine on ferroptosis during intestinal injury in rats after liver transplantation.

Using a rat autologous orthotopic liver transplantation (AOLT) model and liver cold ischemia-reperfusion (I/R)-induced intestinal injury, we clarified whether ferroptosis occurred in rat AOLT cold I/R-induced intestinal injury. Additionally, the role and possible mechanism of the ferroptosis activator sulfasalazine (SAS) in intestinal injury-induced ferroptosis in rats with AOLT liver cold I/R were investigated. Sixty specific pathogen free (SPF)-grade adult male Sprague‒Dawley (SD) rats were randomly divided into 5 groups using the random number table method (n = 12). Six rats were randomly selected at 6 hour (h) and 24 h after I/R. Inferior vena cava blood specimens were collected from the portal vein (PV) opening at 6 h and 24 h. The concentrations of serum malondialdehyde (MDA), serum interleukin 6 (IL-6) were determined by enzyme-linked immunosorbent assay (ELISA). Ileal tissue was obtained from the PV opening in rats in each group at 6 h and 24 h, and ileal tissue sections were observed under light microscopy. The contents of intestinal MDA, superoxide dismutase (SOD), glutathione(GSH), glutathione peroxidase 4 (GPX4), and tissue iron were determined by ELISA, and the expression of GPX4 and the cysteine glutamate reverse transporter light chain protein (xCT) was determined by Western blot. The experimental results show that ferroptosis is involved in the pathophysiological process of intestinal injury induced by cold hepatic ischemia-reperfusion in AOLT rats. In addition, SAS (500 mg/kg) may inhibit the cystine/glutamate antiporters (System Xc¯)/GSH/GPX4 signal axis in intestinal injury induced by cold I/R in rat AOLT liver, or iron overload after reperfusion, causing a massive accumulation of L-ROS and activating cellular ferroptosis, further aggravate the intestinal injury.

The Response of Growth and Transcriptome Profiles of Tea Grey Blight Disease Pathogen Pestalotiopsis theae to the Variation of Exogenous L-Theanine.

Tea grey blight disease is one of the most destructive diseases that infects tea and is caused by the pathogen Pestalotiopsis theae (Sawada) Steyaert. L-theanine is a unique non-protein amino acid of the tea plant. Different concentrations of L-theanine exhibit significant inhibitory effects on the growth and sporulation ability of the pathogen causing tea grey blight disease. To understand the effect mechanism of L-theanine on P. theae, transcriptome profiling was performed on the pathogenic mycelium treated with three different concentrations of L-theanine: no L-theanine treatment (TH0), 20 mg/mL theanine treatment (TH2), and 40 mg/mL theanine treatment (TH4). The colony growths were significantly lower in the treatment with L-theanine than those without L-theanine. The strain cultured with a high concentration of L-theanine produced no spores or only a few spores. In total, 2344, 3263, and 1158 differentially expressed genes (DEGs) were detected by RNA-sequencing in the three comparisons, Th2 vs. Th0, Th4 vs. Th0, and Th4 vs. Th2, respectively. All DEGs were categorized into 24 distinct clusters. According to GO analysis, low concentrations of L-theanine primarily affected molecular functions, while high concentrations of L-theanine predominantly affected biological processes including external encapsulating structure organization, cell wall organization or biogenesis, and cellular amino acid metabolic process. Based on KEGG, the DEGs of Th2 vs. Th0 were primarily involved in pentose and glucuronate interconversions, histidine metabolism, and tryptophan metabolism. The DEGs of Th4 vs. Th0 were mainly involved in starch and sucrose metabolism, amino sugar, and nucleotide sugar metabolism. This study indicated that L-theanine has a significant impact on the growth and sporulation of the pathogen of tea grey blight disease and mainly affects amino acid metabolism, carbohydrate metabolism, and cellular structure-related biosynthesis processes of pathogenic fungi. This work provides insights into the direct control effect of L-theanine on pathogenic growth and also reveals the molecular mechanisms of inhibition of L-theanine to P. theae.

Anti-Obesity Effect and Signaling Mechanism of Potassium Poly-γ-Glutamate Produced by Bacillus subtilis Chungkookjang in High-Fat Diet-Induced Obese Mice.

The purpose of this work was to examine the effects of potassium poly-γ-glutamate (PGA-K) on mice fed a high-fat diet consisting of 60% of total calories for 12 weeks. PGA-K administration reduced the increase in body weight, epididymal fat, and liver weight caused by a high-fat diet compared to the obese group. The triglyceride, low-density lipoprotein cholesterol and high-density lipoprotein cholesterol levels, which are blood lipid indicators, were significantly increased in the obese group but were significantly decreased in the PGA-K-treated group. The administration of PGA-K resulted in a significant inhibition of pro-inflammatory cytokines, including tumor necrosis factor α and interleukin 6. Moreover, the levels of leptin and insulin, which are insulin resistance indicators, significantly increased in the obese group but were significantly decreased in the PGA-K-treated group. These results suggest that PGA-K exhibits a protective effect against obesity induced by a high-fat diet, underscoring its potential as a candidate for obesity treatment.

Current treatments of alcohol use disorder.

Emerging treatments for alcohol dependence reveal an intricate interplay of neurobiological, psychological, and circumstantial factors that contribute to Alcohol Use Disorder (AUD). The approved strategies balancing these factors involve extensive manipulations of neurotransmitter systems such as GABA, Glutamate, Dopamine, Serotonin, and Acetylcholine. Innovative developments are engaging mechanisms such as GABA reuptake inhibition and allosteric modulation. Closer scrutiny is placed on the role of Glutamate in chronic alcohol consumption, with treatments like NMDA receptor antagonists and antiglutamatergic medications showing significant promise. Complementing these neurobiological approaches is the progressive shift towards Personalized Medicine. This strategy emphasizes unique genetic, epigenetic and physiological factors, employing pharmacogenomic principles to optimize treatment response. Concurrently, psychological therapies have become an integral part of the treatment landscape, tackling the cognitive-behavioral dimension of addiction. In instances of AUD comorbidity with other psychiatric disorders, Personalized Medicine becomes pivotal, ensuring treatment and prognosis are closely defined by individual characteristics, as exemplified by Lesch Typology models. Given the high global prevalence and wide distribution of AUD, a persistent necessity exists for development and improvement of treatments. Current research efforts are steadily paving paths towards more sophisticated, effective typology-based treatments: a testament to the recognized imperative for enhanced treatment strategies. The potential encapsulated within the ongoing research suggests a promising future where the clinical relevance of current strategies is not just maintained but significantly improved to effectively counter alcohol dependence.