Search Results (127)

This study aimed to investigate the effects of adding 360 mg/kg niacinamide (NAM) to diets on nutrient metabolism, providing insights into how dietary NAM supplementation enhances nitrogen utilization and growth performance in pigs. Forty growing–finishing pigs were randomly assigned to one of four experimental diets as follows: basal diet + 30 mg/kg NAM (CON), basal diet + 360 mg/kg NAM (CON + NAM), low-protein diet + 30 mg/kg NAM (LP), and low-protein diet + 360 mg/kg NAM (LP + NAM). Results showed that supplementation of both the CON and LP diets with 360 mg/kg NAM resulted in decreased urea nitrogen concentrations and carbamyl phosphate synthetase-I activity (p < 0.05). The pyruvate dehydrogenase activity in the serum and liver, as well as the activity of pyruvate dehydrogenase, citrate synthase, and glutamate dehydrogenase 1 in the ileum mucosa, was increased by supplementing the LP diet with 360 mg/kg NAM (p < 0.05). The LP diet with 360 mg/kg NAM increased the villi length to crypt depth, mRNA expression of glucose transporters 1 and 2 and alanine-serine-cysteine transporter 1, and mRNA expression of mechanistic target of the rapamycin 1 in the ileum (p < 0.05). Additionally, 360 mg/kg NAM supplementation in the LP diet reduced ileal Lactobacillus abundance (LDA > 4) and increased ileal microbial nucleotide and purine metabolism (p < 0.05). Our findings suggest that addition of 360 mg/kg NAM to the LP diet reduced urea production in the liver, enhanced glucose and amino acid absorption and transport in the ileum, and improved glucose metabolism. Full article

Background: Elevated levels of methylmalonic acid (MMA) are observed in the bodily fluids and tissues of patients with methylmalonic aciduria, a metabolic disorder characterized by manifestations such as vomiting, lethargy, muscle weakness, seizures, and coma. Objectives and Methods: To better understand the neuropathological mechanisms underlying this condition, we investigated the effects of intraperitoneal (i.p.) and intracerebroventricular (i.c.v.) administration of MMA on antioxidant defenses, citric acid cycle functioning, and glial reactivity in the cerebral cortex and striatum of Wistar rats. Amino acid levels were also quantified. Results: i.p. and i.c.v. administration of MMA decreased reduced glutathione levels and altered the activities of different antioxidant enzymes in the cortex and striatum. The activity of the citric acid cycle enzyme succinate dehydrogenase was diminished in both brain regions by i.p. and i.c.v. administration. Citrate synthase, isocitrate dehydrogenase, and malate dehydrogenase activities were further inhibited in the striatum. Furthermore, the i.p. administration increased glial fibrillary acidic protein (GFAP) and glucose transporter 1 (GLUT1) levels, whereas i.c.v. administration elevated GFAP and ionized calcium-binding adaptor molecule 1 (IBA1) levels in the striatum, suggesting glial activation. In contrast, no significant changes in glial markers were detected in the cortex. Moreover, synaptophysin levels remained unaltered in both regions. Finally, i.p. administration increased glutamate, glycine, and serine levels and reduced tyrosine concentrations in the striatum. Conclusions: Our findings indicate that oxidative stress, bioenergetic dysfunction, and glial reactivity induced by MMA may contribute to the neurological deficits observed in methylmalonic aciduria. Full article

Background: Addison’s disease (AD) is a rare disorder that often develops in the context of autoimmune polyglandular syndromes. However, the prevalence of rheumatological autoimmune diseases and corresponding autoimmune markers in AD is poorly investigated. Therefore, the present study aims to explore systemic and organ-specific immune markers in a cohort of AD patients from a single tertiary endocrine center. Material and methods: In total, 43 adult AD patients and 31 controls were included in the study. 21-hydroxylase autoantibodies (21OHAb), glutamic acid decarboxylase autoantibodies (GADAbs), zinc transporter-8 autoantibodies (ZnT8Abs), antibodies against nuclear antigens (ANAs), autoantibodies against cyclic citrullinated peptides (CCPAbs), rheumatoid factors (RFs), IgG autoantibodies against cardiolipin (ACLAbs), and autoantibodies against beta-2-Glycoprotein I (β2-GPIAbs) were measured in all participants. Results: An increased prevalence of antibodies against RFs (27.91% vs. 0%, p < 0.001) and ANAs (13.95% vs. 0%, p = 0.037) was found in AD patients compared to controls. Moreover, the titers of 21-hydroxylase and RF antibodies correlated positively (r = +0.269, p = 0.020). The AD patients tended to show an increased prevalence of subthreshold ACL antibody reactivity compared to controls. All patients diagnosed with type 1 diabetes mellitus were GADAb- but not ZnT8Ab-positive. Conclusions: The results show an increased prevalence of ANA and RF positivity in AD patients compared to controls and a significant association between 21-OHAb and RF positivity. ZnT8Ab positivity was not typical for adult AD patients from our ethnic group, while GADAbs were an essential marker for autoimmune diabetes mellitus. Extensive studies in different ethnic groups are needed to establish the clinical significance of various immunological markers for AD comorbidity and the appropriate follow-up protocols for patients with different antibody positivity. Full article

As the average age of the population increases, memory impairment has become an increasingly prevalent issue. This study investigates the effects of 14 days of oral birch sap administration on memory functions in healthy rats using the Morris water maze (MWM) test and explores the underlying mechanisms. A compositional analysis revealed that birch soap is rich in polysaccharides, specifically a low-molecular weight polysaccharide (MW 1.29 kDa), and exhibits no hepatotoxicity or renal toxicity at the tested dose. The results from the MWM test demonstrated that the time and distance required to reach the platform were significantly shorter in the birch sap-treated group compared to the control group, suggesting that birch sap supports memory preservation. Moreover, rats treated with birch sap showed improved cerebral blood flow compared to the control rats. Additionally, in hippocampal nerve terminals (synaptosomes), rats treated with birch sap exhibited a significant increase in evoked glutamate release, as well as elevated levels of presynaptic proteins, including vesicular glutamate transporter 1 (VGluT1), synaptophysin, synaptobrevin, synaptotagmin, syntaxin, synapsin I, and the 25 kDa synaptosome-associated protein (SNAP-25). Transmission electron microscopy also revealed a notable increase in the number of synaptic vesicles in hippocampal synaptosomes of the birch-sap-treated rats. These findings suggest that birch sap enhances hippocampal presynaptic glutamatergic functions and cerebral blood flow, contributing to its memory-preserving effects in rats. Full article

Appropriate fertilization depth promotes the absorption and transport of nutrients, crop growth and yield. However, little is known about whether deep fertilization improves crude protein synthesis and how to regulate it. A two-year field experiment was conducted with various fertilization depths: (1) conventional fertilization (CF), (2) fertilization application depth at 30 cm (DF), and (3) fertilizer average application at depths of 15 cm and 30 cm (AF). The fertilization rates under all treatments were 300 kg N ha⁻¹ nitrogen fertilizer (urea, 46% N), 150 kg P₂O₅ ha⁻¹ calcium superphosphate (16% P₂O₅), and 135 kg K₂O ha⁻¹ potassium sulfate (51% K₂O). The nitrogen/potassium (N/K) ratio, the activities of nitrate reductase [NR], glutamine synthetase [GS], and glutamic pyruvic transaminase [GPT], crude protein content in leaves, stems, and grains, as well as the relationships among the parameters were explored. The result showed that deep fertilization (DF) significantly improved the N/K ratio. NR activity in DF increased by 26.30%, 35.56%, and 57.30% in leaves, stems, and grains, respectively, when compared to conventional fertilization (CF), and by 54.22%, 43.27%, and 28.44% when compared to average fertilization (AF). GS activity in DF increased by 29.67%, 47.96%, and 47.46% in leaves, stems, and grains when compared to CF, and by 40.05%, 31.51%, and 40.62% when compared to AF. GPT activity in DF was significantly higher than CF and AF in grains, and differences between treatments were significant. Crude protein content was significantly correlated with NR and GS activities in leaves, GPT activity in stems, as well as GS and GPT activities in grains. The crude protein content of leaves and grains in DF was significantly higher than in CF and AF. In conclusion, DF significantly improved crude protein synthesis and increased the crude protein content of forage maize by increasing the whole plant N/K ratio, NR and GS activities in leaves, as well as GS and GPT activities in grains. It is a highly efficient cultivation technology that significantly improves the quality of forage maize. Full article

Background: Terahertz (THz) waves, lying between millimeter waves and infrared light, may interact with biomolecules due to their unique energy characteristics. However, whether THz waves are neurally regulated remains controversial, and the underlying mechanism is elusive. Methods: Mouse brain slices were exposed to 1.94 THz waves for 1 h. Synaptic plasticity was evaluated via transmission electron microscopy (TEM), long-term potentiation (LTP), and neuronal class III β-tubulin (Tuj1) and synaptophysin (SYN) expression. Immunofluorescence (IF) and electrophysiology were used to identify neurons sensitive to THz waves. The calcium activity of excitatory neurons, glutamate receptor currents, and glutamate neuron marker expression was also assessed using calcium imaging, a patch clamp, and Western blotting (WB). Optogenetics and chemogenetics were used to determine the role of excitatory neurons in synaptic plasticity impairment after THz wave exposure. NMDA receptor 2B (GluN2B) was overexpressed in the ventral hippocampal CA1 (vCA1) by a lentivirus to clarify the role of GluN2B in THz wave-induced synaptic plasticity impairment. Results: Exposure to 1.94 THz waves increased postsynaptic density (PSD) thickness and reduced the field excitatory postsynaptic potential (fEPSP) slope and Tuj1 and SYN expression. THz waves diminished vCA1 glutamatergic neuron activity and excitability, neural electrical activity, and glutamate transporter function. THz waves reduced N-methyl-D-aspartate receptor (NMDAR) current amplitudes and NMDAR subunit expression. Activating vCA1 glutamatergic neurons through optogenetics and chemogenetics mitigated THz wave-induced synaptic plasticity impairment. GluN2B subunit overexpression improved synaptic plasticity marker expression, synaptic ultrastructure, and the fEPSP slope. Conclusions: Exposure to 1.94 THz waves decreased synaptic plasticity, glutamatergic neuron excitability, and glutamatergic synaptic transmission in the vCA1. Glutamatergic neuron activation and GluN2B overexpression alleviated THz wave-induced synaptic plasticity impairment; thus, neuromodulation could be a promising therapeutic strategy to mitigate the adverse effects of THz radiation. Full article

Glomerular podocytes act as a part of the filtration barrier in the kidney. The activity of this filter is regulated by ionotropic and metabotropic glutamate receptors. Adjacent podocytes can potentially release glutamate into the intercellular space; however, little is known about how podocytes release glutamate. Here, we demonstrated vesicular glutamate transporter 3 (VGLUT3)-dependent glutamate release from podocytes. Immunofluorescence analysis revealed that rat glomerular podocytes and an immortal mouse podocyte cell line (MPC) express VGLUT1 and VGLUT3. Consistent with this finding, quantitative RT-PCR revealed the expression of VGLUT1 and VGLUT3 mRNA in undifferentiated and differentiated MPCs. In addition, the exocytotic proteins vesicle-associated membrane protein 2, synapsin 1, and synaptophysin 1 were present in punctate patterns and colocalized with VGLUT3 in MPCs. Interestingly, approximately 30% of VGLUT3 colocalized with VGLUT1. By immunoelectron microscopy, VGLUT3 was often observed around clear vesicle-like structures in differentiated MPCs. Differentiated MPCs released glutamate following depolarization with high potassium levels and after stimulation with the muscarinic agonist pilocarpine. The depletion of VGLUT3 in MPCs by RNA interference reduced depolarization-dependent glutamate release. These results strongly suggest that VGLUT3 is involved in glutamatergic signalling in podocytes and may be a new drug target for various kidney diseases. Full article

Terahertz (THz) waves, a novel type of radiation with quantum and electronic properties, have attracted increasing attention for their effects on the nervous system. Spatial working memory, a critical component of higher cognitive function, is coordinated by brain regions such as the infralimbic cortex (IL) region of the medial prefrontal cortex and the ventral cornu ammonis 1 (vCA1) of hippocampus. However, the regulatory effects of THz waves on spatial working memory and the underlying mechanisms remain unclear. In this study, the effects of 0.152 THz waves on glutamatergic neuronal activity and spatial working memory and the related mechanisms were investigated in cell, brain slice, and mouse models. Cellular experiments revealed that THz waves exposure for 60 min significantly increased the intrinsic excitability of primary hippocampal neurons, enhanced glutamatergic neuron activity, and upregulated the expression of molecules involved in glutamate metabolism. In brain slice experiments, THz waves markedly elevated neuronal activity, promoted synaptic plasticity, and increased glutamatergic synaptic transmission within the IL and vCA1 regions. Molecular dynamics simulations found that THz waves could inhibit the ion transport function of glutamate receptors. Moreover, Y-maze tests demonstrated that mice exposed to THz waves exhibited significantly improved spatial working memory. Multiomics analyses indicated that THz waves could induce changes in chromatin accessibility and increase the proportion of excitatory neurons. These findings suggested that exposure to 0.152 THz waves increased glutamatergic neuronal activity, promoted synaptic plasticity, and improved spatial working memory, potentially through modifications in chromatin accessibility and excitatory neuron proportions. Full article

Background/Objectives: Late epilepsy occurring in the late stage after glioblastoma (GBM) resection is suggested to be caused by increased extracellular glutamate (Glu). To elucidate the mechanism underlying postoperative late epilepsy, the present study aimed to investigate the expressions and relations of molecules related to Glu metabolism in tumor tissues from GBM patients and cultured glioma stem-like cells (GSCs). Methods: Expressions of CD44, xCT and excitatory amino acid transporter (EAAT) 2 and extracellular Glu concentration in GBM patients with and without epilepsy were examined and their relationships were analyzed. For the study using GSCs, expressions and relationships of the same molecules were analyzed and the effects of CD44 knock-down on xCT, EAAT2, and Glu were investigated. In addition, the effects of hypoxia on the expressions of these molecules were investigated. Results: Tumor tissues highly expressed CD44 and xCT in the periphery of GBM with epilepsy, whereas no significant difference in EAAT2 expression was seen between groups with and without epilepsy. Extracellular Glu concentration was higher in patients with epilepsy than those without epilepsy. GSCs displayed reciprocal expressions of CD44 and xCT. Concentrations of extracellular Glu coincided with the degree of xCT expression, and CD44 knock-down elevated xCT expression and extracellular Glu concentrations. Hypoxia of 1% O₂ elevated expression of CD44, while 5% O₂ increased xCT and extracellular Glu concentration. Conclusions: Late epilepsy after GBM resection was related to extracellular Glu concentrations that were regulated by reciprocal expression of CD44 and xCT, which were stimulated by differential hypoxia for each molecule. Full article

The current opinion manuscript posits that not only Piezo2 voltage block, but also proton affinity and availability in relation to Piezo2, a mechanically gated ion channel, may count in the mediation of pain and its sensitivity. Moreover, this paper argues that autonomously acquired Piezo2 channelopathy on somatosensory terminals is likely the initiating peripheral impaired input source that drives the central sensitization of spinal nociceptive neurons on the chronic path as being the autonomous pain generator. In parallel, impaired proprioception and the resultant progressive deficit in neuromuscular junctions of motoneurons might be initiated on the chronic path by the impairment of the proton-based ultrafast proprioceptive feedback to motoneurons due to disconnection through vesicular glutamate transporter 1. The irreversible form of this autonomously acquired Piezo2 ion channel microdamage, in association with genetic predisposition and/or environmental risk factors, is suggested to lead to progressive motoneuron death in addition to loss of pain sensation in amyotrophic lateral sclerosis. Furthermore, the impairment of the proton-based ultrafast long-range oscillatory synchronization to the hippocampus through vesicular glutamate transporter 2 may gain further importance in pain modulation and formation on the chronic path. Overall, this novel, unaccounted Piezo2-initiated protonic extrafast signaling, including both the protonic ultrafast proprioceptive and the rapid nociceptive ones, within the nervous system seems to be essential in order to maintain life. Hence, its microdamage promotes neurodegeneration and accelerates aging, while the complete loss of it is incompatible with life sustainment, as is proposed in amyotrophic lateral sclerosis. Full article

γ-Aminobutyric acid (GABA), an endogenous amino acid widely found in living organisms, has important functions in plants such as regulating growth and development, maintaining carbon and nitrogen nutrient balance, and coping with adversity. In this study, we investigated the effects of exogenous 0.5 mmol/L GABA on the growth, antioxidant metabolism, and GABA shunt metabolism of tall fescue under 20 μmol/L Cd stress, using tall fescue (Festuca arundinacea) ‘Ruby II’ under hydroponics conditions. The results showed that (1) applying GABA for 3, 7, 11, and 15 d under Cd stress inhibited Cd transport from roots to leaves and promoted plant height, alleviating the effects of Cd stress on plant growth. (2) Exogenous 0.5 mmol/L GABA had an interesting regulatory effect on the activation of the antioxidant enzyme system induced by stress at different stages, which was accompanied by a decrease in malondialdehyde (MDA) contents and alleviated the degree of cell membrane lipid peroxidation under cadmium stress. Specifically, peroxidase (POD) enzyme activity reactions initially responded on the 3rd and 7th days of stress, and the changes in catalase (CAT) enzyme activities concentrated on the 11th and 15th days of the later stage. Ascorbate peroxidase (APX) enzyme was active throughout the whole stress period in the roots. Multiple factorial analyses further proved that the antioxidant pathway strongly influenced the survival and growth of tall fescue under stress in the presence of GABA. (3) Application of exogenous GABA activated the branching pathway for GABA synthesis from Glu decarboxylation (GABA shunt) with a higher contribution in the leaves, which induced changes in glutamate content, and plants maintained a higher endogenous GABA content and signal to regulate the plant antioxidant system and reduce cell membrane damage, thus improving the tolerance of plants to Cd stress. Full article

Background/Objectives: Cocaine use disorder is an intersecting issue in populations with HIV-1, further exacerbating the clinical course of the disease and contributing to neurotoxicity and neuroinflammation. Cocaine and HIV neurotoxins play roles in neuronal damage during neuroHIV progression by disrupting glutamate homeostasis in the brain. Even with combined antiretroviral therapy (cART), HIV-1 Nef, an early viral protein expressed in approximately 1% of infected astrocytes, remains a key neurotoxin. This study investigates the relationship among Nef, glutamate homeostasis, and cocaine in the nucleus accumbens (NAc), a critical brain region associated with drug motivation and reward. Methods: Male and female Sprague Dawley rats were used to compare the effects of astrocytic Nef and cocaine by molecular analysis of glutamate transporters, GLT-1 and the cysteine glutamate exchanger (xCT), in the NAc. Behavioral assessments for cocaine self-administration were used to evaluate cocaine-seeking behavior. Results: The findings indicate that both cocaine and Nef independently decrease the expression of the glutamate transporter GLT-1 in the NAc. Additionally, rats with astrocytic Nef expression exhibited increased cocaine-seeking behavior but demonstrated sex-dependent molecular differences after the behavioral paradigm. Conclusions: The results suggest that the expression of Nef intensifies cocaine-induced alterations in glutamate homeostasis in the NAc, potentially underlying increased cocaine-seeking behavior. Understanding these interactions better may inform therapeutic strategies for managing cocaine use disorder in HIV-infected individuals. Full article

The insulin-regulated aminopeptidase (IRAP; oxytocinase) is part of the M1 aminopeptidase family and is highly expressed in many tissues, including the neocortex and hippocampus of the brain. IRAP is involved in various physiological functions and has been identified as a receptor for the endogenous hexapeptide Angiotensin IV (Ang IV). The binding of Ang IV inhibits the enzymatic activity of IRAP and has been proven to enhance learning and memory in animal models. The macrocyclic compound 9 (C9) is a potent synthetic IRAP inhibitor developed from the previously reported inhibitor HA08. In this study, we have examined compound C9 and its effects on cognitive markers drebrin, microtubule-associated protein 2 (MAP2), and glial fibrillary acidic protein (GFAP) in primary hippocampal and cortical cultures. Cells from Sprague Dawley rats were cultured for 14 days before treatment with C9 for 4 consecutive days. The cells were analysed for protein expression of drebrin, MAP2, GFAP, glucose transporter type 4 (GLUT4), vesicular glutamate transporter 1 (vGluT1), and synapsin I using immunocytochemistry. The gene expression of related proteins was determined using qPCR, and viability assays were performed to evaluate toxicity. The results showed that protein expression of drebrin and MAP2 was increased, and the corresponding mRNA levels were decreased after treatment with C9 in the hippocampal cultures. The ratio of MAP2-positive neurons and GFAP-positive astrocytes was altered and there were no toxic effects observed. In conclusion, the IRAP inhibitor compound C9 enhances the expression of the pro-cognitive markers drebrin and MAP2, which further confirms IRAP as a relevant pharmaceutical target and C9 as a promising candidate for further investigation. Full article

Amino acid transporters play pivotal roles in cancer biology, including in urological cancers. Among them, L-type amino acid transporter 1 (LAT1), alanine-serine-cysteine transporter 2 (ASCT2), and cystine-glutamate transporter (xCT) have garnered significant attention due to their involvement in various aspects of tumor progression and response to therapy. This review focuses on elucidating the regulation and functions of these amino acid transporters in urological cancers, including prostate, bladder, and renal cancers. Understanding the intricate regulatory mechanisms governing these amino acid transporters is essential for developing effective therapeutic strategies. Furthermore, exploring their interactions with signaling pathways and microenvironmental cues in the context of urological cancers may uncover novel therapeutic vulnerabilities. This comprehensive overview highlights the importance of amino acid transporters, particularly LAT1, ASCT2, and xCT, in urological cancers and underscores the potential of their inhibitors as therapeutic targets for improving patient outcomes. Full article

Schizophrenia is a neuropsychiatric illness characterized by altered neurotransmission, in which adenosine, a modulator of glutamate and dopamine, plays a critical role that is relatively unexplored in the human brain. In the present study, postmortem human brain tissue from the anterior cingulate cortex (ACC) of individuals with schizophrenia (n = 20) and sex- and age-matched control subjects without psychiatric illness (n = 20) was obtained from the Bronx–Mount Sinai NIH Brain and Tissue Repository. Enriched populations of ACC pyramidal neurons were isolated using laser microdissection (LMD). The mRNA expression levels of six key adenosine pathway components—adenosine kinase (ADK), equilibrative nucleoside transporters 1 and 2 (ENT1 and ENT2), ectonucleoside triphosphate diphosphohydrolases 1 and 3 (ENTPD1 and ENTPD3), and ecto-5′-nucleotidase (NT5E)—were quantified using real-time PCR (qPCR) in neurons from these individuals. No significant mRNA expression differences were observed between the schizophrenia and control groups (p > 0.05). However, a significant sex difference was found in ADK mRNA expression, with higher levels in male compared with female subjects (Mann–Whitney U = 86; p < 0.05), a finding significantly driven by disease (t₍₁₇₎ = 3.289; p < 0.05). Correlation analyses also demonstrated significant associations (n = 12) between the expression of several adenosine pathway components (p < 0.05). In our dementia severity analysis, ENTPD1 mRNA expression was significantly higher in males in the “mild” clinical dementia rating (CDR) bin compared with males in the “none” CDR bin (F_{(2, 13)} = 5.212; p < 0.05). Lastly, antipsychotic analysis revealed no significant impact on the expression of adenosine pathway components between medicated and non-medicated schizophrenia subjects (p > 0.05). The observed sex-specific variations and inter-component correlations highlight the value of investigating sex differences in disease and contribute to the molecular basis of schizophrenia’s pathology. Full article