RESUMO
Abstract This study was carried out to evaluate the effect of Glutamine, as a dipeptide or a free amino acid form, on the progression of burn injuries in rats. Thirty male Wistar rats were burned with a comb metal plate heated in boiling water (98 °C) for three minutes, creating four rectangular full-thickness burn areas separated by three unburned interspaces (zone of stasis) in both dorsum sides. The animals were randomized into three groups (n=10): saline solution (G1-Control) and treated groups that orally received Glutamine as dipeptide (G2-Dip) or free amino acid (G3-FreeAA). Two and seven days after burn injury, lesions were photographed for unburned interspaces necrosis evolution assessment. Seven days after injury, glutathione seric was measured and histopathological analysis was performed. By photographs, there was a significant reduction in necrosis progression in G3-Free-AA between days two and seven. Histopathological analysis at day 7 showed a significantly higher stasis zone without necrosis and a higher number of fibroblasts in G2-Dip and G3-FreeAA compared with G1-Control. Also, glutathione serum dosage was higher in G2-Dip. The plasmatic glutathione levels were higher in the G2-Dip than the G1-Control, and there was a trend to higher levels in G3-FreeAA. The reduction in histological lesions, greater production of fibroblasts, and greater amounts of glutathione may have benefited the evolution of burn necrosis, which showed greater preservation of interspaces.
Resumo Este estudo foi realizado para avaliar o efeito da Glutamina, como um dipeptídeo ou forma de aminoácido livre, na progressão de queimaduras em ratos. Trinta ratos Wistar machos foram queimados com um pente de metal aquecido em água fervente (98 °C) por três minutos, criando quatro áreas retangulares queimadas separadas por três interesespaços não queimados (zona de estase) em ambos os lados do dorso. Os animais foram randomizados em três grupos (n = 10): solução salina (G1-Controle) e grupos tratados que receberam glutamina via oral como dipeptídeo (G2-Dip) ou aminoácido livre (G3-FreeAA). Dois e sete dias após a queimadura, as lesões foram fotografadas para avaliação da evolução da necrose entre os espaços não queimados. Sete dias após a lesão, foi dosada a glutationa sérica e realizada análise histopatológica. Pelas fotografias, houve uma redução significativa na progressão da necrose no G3-Free-AA entre os dias dois e sete. A análise histopatológica no dia 7 mostrou uma zona de estase significativamente maior sem necrose e número mais elevado de fibroblastos em G2-Dip e G3-FreeAA em comparação com G1-Controle. Os níveis plasmáticos de glutationa foram maiores no G2-Dip em relação ao G1-Controle, e houve tendência a níveis mais elevados no G3-FreeAA. A redução das lesões histológicas, maior produção de fibroblastos, maior quantidade de glutationa podem ter beneficiado a evolução da necrose da queimadura, que mostrou maior preservação dos interespaços.
Assuntos
Animais , Masculino , Ratos , Queimaduras/tratamento farmacológico , Glutamina , Ratos Wistar , Dipeptídeos , Modelos Animais de Doenças , AminoácidosRESUMO
PURPOSE: It is important to determine the approaches for oral mucositis (OM) care in pediatric oncology clinics to reflect the profile of practices. The aim of this study was to report on current nursing care approaches for OM in Türkiye. METHODS: The descriptive, cross-sectional study was conducted with nurse managers in pediatric oncology centers in Türkiye between April and December 2022. The data were obtained online by reaching pediatric oncology nurse managers. The data was collected with the "Oral Mucositis Care Application Form" developed by the researchers based on current literature. RESULTS: The study reached approximately 60% (n = 41) of pediatric oncology clinics across Türkiye. Oral assessment of children was mainly conducted by nurses (95.1%), and 53.7% of clinics used the WHO Oral Mucositis Assessment Scale. To prevent OM, oral care routines were performed twice a day (36.6%) using sodium bicarbonate (61%) and 0.9% sodium chloride (26.8%) agents. For oral mucositis management, pharmacological agents included glutamine (oral) (51.2%), chlorhexidine (43.9%), and benzydamine hydrochloride (36.6%), while non-pharmacological agents included black mulberry syrup (41.5%), honey (19.8%), and chewing gum (9.8%). Chlorhexidine and benzydamine hydrochloride were used for all mucositis grades, while glutamine was frequently used for grades 2 and above. CONCLUSIONS: The study revealed that the practices related to preventing and managing oral mucositis in pediatric oncology clinics in Türkiye are heterogeneous. These findings will contribute to the existing literature on the multidisciplinary, systematic, and evidence-based approaches used in oral mucositis care in Türkiye.
Assuntos
Benzidamina , Mucosite , Neoplasias , Estomatite , Criança , Humanos , Estudos Transversais , Clorexidina , Glutamina , Estomatite/tratamento farmacológico , Estomatite/etiologia , Neoplasias/complicaçõesRESUMO
Glutamine (Gln), glutamate (Glu), and γ-amino butyric acid (GABA) are essential amino acids for brain metabolism and function. Astrocyte-derived Gln is the precursor for the two most important neurotransmitters in the central nervous system (CNS), which are the excitatory neurotransmitter Glu and the inhibitory neurotransmitter GABA. In addition to their roles in neurotransmission, these amino acids can be used as alternative substrates in brain metabolism that enable metabolic coupling between astrocytes and neurons in the glutamate-glutamine cycle (GGC). The disturbed homeostasis of these amino acids within the tripartite synapse may be involved in the pathogenesis of various neurological diseases. Interactions between astrocytes and neurons in terms of Gln, Glu, and GABA homeostasis were studied in different phases of experimental allergic encephalomyelitis (EAE) in Lewis rats. The results of the study showed a decrease in the transport (uptake and release) of Gln and GABA in both neuronal and astrocyte-derived fractions. These effects were fully or partially reversed when the EAE rats were treated with memantine, a NMDA receptor antagonist. Changes in the expression and activity of selected glutamine/glutamate metabolizing enzymes, such as glutamine synthase (GS) and phosphate-activated glutaminase (PAG), which were affected by memantine, were observed in different phases of EAE. The results suggested perturbed homeostasis of Gln, Glu, and GABA during EAE, which may indicate alterations in neuron-astrocyte coupling and dysfunction of the tripartite synapse. Memantine appears to partially regulate the disturbed relationships between Gln, Glu, and GABA.
Assuntos
Antifibrinolíticos , Encefalomielite Autoimune Experimental , Animais , Ratos , Ratos Endogâmicos Lew , Encefalomielite Autoimune Experimental/tratamento farmacológico , Glutamina , Memantina/farmacologia , Memantina/uso terapêutico , Encéfalo , Ácido Glutâmico , Ácido gama-Aminobutírico , Aminoácidos , HomeostaseRESUMO
Proteins with extended polyglutamine regions are associated with several neurodegenerative disorders, including Huntington's disease. Intracellular proteolytic processing of these proteins is not well understood. In particular, it is unclear whether long polyglutamine fragments resulting from the proteolysis of these proteins can be potentially cleaved by the proteasome. Here, we studied the susceptibility of the glutamine-glutamine bond to proteolysis by the proteasome using oligoglutamine-containing peptides with a fluorophore/quencher pair. We found that the addition of the 11S proteasomal regulator (also known as PA28) significantly accelerated the hydrolysis of oligoglutamine-containing peptides by the 20S proteasome. Unexpectedly, a similar effect was observed for the 26S proteasome in the presence of the 11S regulator. LC/MS data revealed that the hydrolysis of our peptides with both 20S and 26S proteasomes leads to N-terminal fragments containing two or three glutamine residues and that the hydrolysis site does not change after the addition of the 11S regulator. This was confirmed by the docking experiment, which shows that the preferred hydrolysis site is located after the second/third glutamine residue. Inhibitory analysis revealed that trypsin-like specificity is mainly responsible for the proteasomal hydrolysis of the glutamine-glutamine bond. Together, our results indicate that both 20S and 26S proteasomes are capable of degrading the N-terminal part of oligoglutamine fragments, while the 11S regulator significantly accelerates the hydrolysis without changing its specificity. This data suggests that proteasome activity may be enhanced in relation to polyglutamine substrates present in neurons in the early stages of polyglutamine disorders.
Assuntos
Glutamina , Complexo de Endopeptidases do Proteassoma , Hidrólise , Encéfalo , PeptídeosRESUMO
BACKGROUND: Osteoporosis (OP), often referred to as the "silent disease of the twenty-first century," poses a significant public health concern due to its severity, chronic nature, and progressive course, predominantly affecting postmenopausal women and elderly individuals. The pathogenesis and progression of this disease have been associated with dysregulation in tumor metabolic pathways. Notably, the metabolic utilization of glutamine has emerged as a critical player in cancer biology. While metabolic reprogramming has been extensively studied in various malignancies and linked to clinical outcomes, its comprehensive investigation within the context of OP remains lacking. METHODS: This study aimed to identify and validate potential glutamine metabolism genes (GlnMgs) associated with OP through comprehensive bioinformatics analysis. The identification of GlnMgs was achieved by integrating the weighted gene co-expression network analysis and a set of 28 candidate GlnMgs. Subsequently, the putative biological functions and pathways associated with GlnMgs were elucidated using gene set variation analysis. The LASSO method was employed to identify key hub genes, and the diagnostic efficacy of five selected GlnMgs in OP detection was assessed. Additionally, the relationship between hub GlnMgs and clinical characteristics was investigated. Finally, the expression levels of the five GlnMgs were validated using independent datasets (GSE2208, GSE7158, GSE56815, and GSE35956). RESULTS: Five GlnMgs, namely IGKC, TMEM187, RPS11, IGLL3P, and GOLGA8N, were identified in this study. To gain insights into their biological functions, particular emphasis was placed on synaptic transmission GABAergic, inward rectifier potassium channel activity, and the cytoplasmic side of the lysosomal membrane. Furthermore, the diagnostic potential of these five GlnMgs in distinguishing individuals with OP yielded promising results, indicating their efficacy as discriminative markers for OP. CONCLUSIONS: This study discovered five GlnMgs that are linked to OP. They shed light on potential new biomarkers for OP and tracking its progression.
Assuntos
Biologia Computacional , Glutamina , Idoso , Humanos , Feminino , Glutamina/genética , Imunoterapia , Aprendizado de Máquina , Perfilação da Expressão Gênica , Proteínas de MembranaRESUMO
Renal interstitial fibrosis (RIF), a progressive process affecting the kidneys in chronic kidney disease (CKD), currently lacks an effective therapeutic intervention. Traditional Chinese medicine (TCM) has shown promise in reducing RIF and slowing CKD progression. In this study, we demonstrated the dose-dependent attenuation of RIF by Ootheca mantidis (SPX), a commonly prescribed TCM for CKD, in a mouse model of unilateral ureteral obstruction (UUO). RNA-sequencing analysis suggested that SPX treatment prominently downregulated apoptosis and inflammation-associated pathways, thereby inhibiting the fibrogenic signaling in the kidney. We further found that transplantation of fecal microbiota from SPX-treated mice conferred protection against renal injury and fibrosis through suppressing apoptosis in UUO mice, indicating that SPX ameliorated RIF via remodeling the gut microbiota and reducing apoptosis in the kidneys. Further functional exploration of the gut microbiota combined with fecal metabolomics revealed increased levels of some probiotics, including Akkermansia muciniphila (A. muciniphila), and modulations in glutamine-related amino acid metabolism in UUO mice treated with SPX. Subsequent colonization of A. muciniphila and supplementation with glutamine effectively mitigated cell apoptosis and RIF in UUO mice. Collectively, these findings unveil a functionally A. muciniphila- and glutamine-involved gut-renal axis that contributes to the action of SPX, and provide important clue for the therapeutic potential of SPX, A. muciniphila, and glutamine in combatting RIF.
Assuntos
Microbioma Gastrointestinal , Insuficiência Renal Crônica , Obstrução Ureteral , Animais , Camundongos , Glutamina , Apoptose , FibroseRESUMO
L-glutaminase is a hydrolytic enzyme with wide biotechnological applications. Mostly, these enzymes are employed in the feed industry for flavor enhancement and acrylamide mitigation. Also, L-glutaminase may have antiviral and antineoplastic effects making it a good choice for pharmaceutical applications. In this study, the strain Monascus ruber URM 8542 was identified through classical and molecular taxonomy using partial sequencing of ß-tubulin and calmodulin genes. Subsequently, the optimal culture conditions were evaluated by submerged fermentation (L-glutamine 10 g.L- 1) for L-glutaminase excretion. The isolate was identified as M. ruber URM 8542 which showed significant extracellular enzyme production with a yield of 11.4 times in relation to the specific activity of intracellular L-glutaminase. Regarding the optimization experiments, several factors such as L-glutamine concentration, temperature, and pH were compared using a full factorial design (23). The concentrations greater than 1% proved to be significantly better for glutaminase production (R2 = 0.9077). Additionally, the L-glutaminase was optimally active at pH 7.0 and 30 ºC. The L-glutaminase was remarkably stable across an alkaline pH range (7.0-8.0) and had a thermal stability ranging from 30 ºC to 60 ºC for 1 h. Taken together, these findings suggest that the L-glutaminase produced by M. ruber is a promising candidate for pharmacological application, although further studies need to be performed. To the best of our knowledge, this is the first report of L-glutaminase production by Monascus ruber.
Assuntos
Sorvetes , Monascus , Glutaminase/genética , Glutamina , Monascus/genéticaRESUMO
Abnormal 5-methylcytosine (m5C) methylation has been proved to be closely related to gastric carcinogenesis, progression, and prognosis. Dysregulated long noncoding RNAs (lncRNAs) participate in a variety of biological processes in cancer. However, to date, m5C-methylated lncRNAs are rarely researched in gastric cancer (GC). Here, we found that RNA cytosine-C(5)-methyltransferase (NSUN2) was upregulated in GC and high NSUN2 expression was associated with poor prognosis. NR_033928 was identified as an NSUN2-methylated and upregulated lncRNA in GC. Functionally, NR_033928 upregulated the expression of glutaminase (GLS) by interacting with IGF2BP3/HUR complex to promote GLS mRNA stability. Increased glutamine metabolite, α-KG, upregulated NR_033928 expression by enhancing its promoter 5-hydroxymethylcytosine (hm5C) demethylation. In conclusion, our results revealed that NSUN2-methylated NR_033928 promoted GC progression and might be a potential prognostic and therapeutic target for GC.
Assuntos
RNA Longo não Codificante , Neoplasias Gástricas , Humanos , RNA Longo não Codificante/genética , RNA Longo não Codificante/metabolismo , Glutamina , Glutaminase/genética , Neoplasias Gástricas/genética , Neoplasias Gástricas/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Proliferação de Células/genéticaRESUMO
Stabilization and reusability of enzyme transglutaminase (TGM) are important goals for the enzymatic process since immobilizing TGM plays an important role in different technologies and industries. TGM can be used in many applications. In the food industry, it plays a role as a protein-modifying enzyme, while, in biotechnology and pharmaceutical applications, it is used in mediated bioconjugation due to its extraordinary crosslinking ability. TGMs (EC 2.3.2.13) are enzymes that catalyze the formation of a covalent bond between a free amino group of protein-bound or peptide-bound lysine, which acts as an acyl acceptor, and the γ-carboxamide group of protein-bound or peptide-bound glutamine, which acts as an acyl donor. This results in the modification of proteins through either intramolecular or intermolecular crosslinking, which improves the use of the respective proteins significantly.
Assuntos
Proteínas , Transglutaminases , Transglutaminases/metabolismo , Biotecnologia , Peptídeos , GlutaminaRESUMO
This study aims to explore the relationship between macrosomia and amino acids in maternal and cord sera. METHODS: In the case-control study, 78 pairs of mothers and newborns were recruited from December 2016 to November 2019. Participants were divided into the macrosomia group (BW ≥ 4000 g, n = 39) and the control group (BW between 2500 g and 3999 g, n = 39) according to the birth weight (BW) of newborns. Maternal vein blood samples were collected before delivery and cord vein blood samples were collected after birth. The levels of amino acids in maternal and cord sera were measured by liquid chromatography and mass spectrometry (LC-MS/MS) in the year 2021. The difference in amino acid levels in maternal and cord sera between the two groups was compared, and the contribution of each amino acid to the difference between the two groups was analyzed. Unconditional logistic regression analysis was used to test the relationship between macrosomia and amino acids. RESULTS: In maternal serum during the antepartum, the levels of asparagine, glutamine, methionine, alanine, and threonine in the macrosomia group were higher but arginine was lower than that in the control group (p < 0.05). In cord serum, the levels of lysine, histidine, phenylalanine, arginine, tryptophan, valine, isoleucine, glutamate, tyrosine, and total essential amino acid (EAA) in the macrosomia group were lower while glutamine was higher than that in the control group (p < 0.05). The ratios of EAA, valine, threonine, methionine, tryptophan, and alanine in maternal serum to those in cord serum were higher, while the ratio of glutamine was lower in the macrosomia group (p < 0.05). Arginine and threonine in maternal serum and glutamate, glutamine, and histidine in cord serum were associated with macrosomia (p < 0.05). CONCLUSION: Most of the amino acid levels in the maternal sera of the macrosomia group are higher than those in the control group, while most of the amino acids' levels in the cord sera of the macrosomia group are lower than those in the control group. The ratios of some amino acids in maternal serum to those in cord serum were different between the two groups. Arginine and threonine in maternal serum and glutamate, glutamine, and histidine in cord serum are closely related to macrosomia.
Assuntos
Aminoácidos , Histidina , Feminino , Recém-Nascido , Humanos , Triptofano , Glutamina , Macrossomia Fetal , Cromatografia Líquida , Estudos de Casos e Controles , Leucina , Espectrometria de Massas em Tandem , Alanina , Metionina , Valina , Treonina , Arginina , Ácido GlutâmicoRESUMO
Solute carrier family 1 member 5 (SLC1A5) is a member of the solute carrier (SLC) superfamily of transporters and plays an important role in tumors as a key transporter of glutamine into cells. However, the relationship between SLC1A5, which is involved in immune regulation, and immune cell infiltration in the tumor microenvironment has not been elucidated, and the relationship between SLC1A5 and ferroptosis is rarely reported. Therefore, we comprehensively analyzed the expression level of SLC1A5 across cancers and compared it with that in normal tissues. Then, the relationship between SLC1A5 expression and the tumor immune microenvironment was analyzed by single-cell analysis, gene set enrichment analysis (GSEA), and Tumor Immune Estimation Resource (TIMER). Next, the correlations of the SLC1A5 expression level with immunotherapy response, immunomodulator expression, tumor mutation burden (TMB) and microsatellite instability (MSI) were evaluated. Finally, in vitro experiments verified that SLC1A5 participates in ferroptosis of glioma cells to regulate tumor progression. Our results indicated that SLC1A5 is aberrantly expressed in most cancer types and closely associated with prognosis. The GSEA results showed that SLC1A5 is involved in immune activation processes and closely related to the infiltration levels of different immune cells in different cancer types. Upon further investigation, we found that SLC1A5 is a suppressor of ferroptosis in glioma, and SLC1A5 knockdown inhibited the proliferation and migration of glioma cells in vitro. In conclusion, we conducted a pancancer analysis of SLC1A5, demonstrated its role as a prognostic biomarker in cancer patients and explored its potential biological functions.
Assuntos
Ferroptose , Glioma , Humanos , Ferroptose/genética , Biomarcadores , Adjuvantes Imunológicos , Glutamina , Proteínas de Membrana Transportadoras , Microambiente Tumoral/genética , Antígenos de Histocompatibilidade Menor , Sistema ASC de Transporte de Aminoácidos/genéticaRESUMO
Anaplastic thyroid cancer (ATC) is one of the most aggressive tumors with an extremely poor prognosis. Based on the several biological features related to glutamine metabolism in ATC, we hypothesized glutaminolysis inhibition induces cell death in ATC cells. However, glutamine metabolism inhibition triggered cell growth arrest independent of cell death in ATC, suggesting that other signaling pathways avoid glutamine metabolism inhibition-induced stress exist. To investigate the functional mechanism against glutamine metabolism inhibition, we conducted mRNA and ATAC-Sequencing data analysis and found that glutamine deprivation increased ATF4-mediated one-carbon metabolism. When we inhibited PHGDH, the first rate-limiting enzyme for one-carbon metabolism, cell growth arrest was promoted upon glutamine metabolism inhibition by accumulating intracellular ROS. We next observed that the co-inhibition of glutamine and one-carbon metabolism could augment the anticancer effects of drugs used in patients with ATC. Finally, single-cell RNA sequencing analysis revealed that one-carbon metabolism was strengthened through the evolutionary process from PTC to ATC. Collectively, our data demonstrate that one-carbon metabolism has a potential role of modulation of cell fate in metabolic stress and can be a therapeutic target for enhancing antitumor effects in ATC.
Assuntos
Carcinoma Anaplásico da Tireoide , Neoplasias da Glândula Tireoide , Humanos , Carcinoma Anaplásico da Tireoide/tratamento farmacológico , Carcinoma Anaplásico da Tireoide/genética , Carcinoma Anaplásico da Tireoide/metabolismo , Neoplasias da Glândula Tireoide/tratamento farmacológico , Neoplasias da Glândula Tireoide/genética , Neoplasias da Glândula Tireoide/metabolismo , Espécies Reativas de Oxigênio , Glutamina , Linhagem Celular Tumoral , CarbonoRESUMO
This study was to investigate the effects of ammonia and manganese in the metabolism of minimal hepatic encephalopathy (MHE). A total of 32 Sprague-Dawley rats were divided into four subgroups: chronic hyperammonemia (CHA), chronic hypermanganese (CHM), MHE and control group (CON). 1H-NMR-based metabolomics was used to detect the metabolic changes. Sparse projection to latent structures discriminant analysis was used for identifying and comparing the key metabolites. Significant elevated blood ammonia were shown in the CHA, CHM, and MHE rats. Significant elevated brain manganese (Mn) were shown in the CHM, and MHE rats, but not in the CHA rats. The concentrations of γ-amino butyric acid (GABA), lactate, alanine, glutamate, glutamine, threonine, and phosphocholine were significantly increased, and that of myo-inositol, taurine, leucine, isoleucine, arginine, and citrulline were significantly decreased in the MHE rats. Of all these 13 key metabolites, 10 of them were affected by ammonia (including lactate, alanine, glutamate, glutamine, myo-inositol, taurine, leucine, isoleucine, arginine, and citrulline) and 5 of them were affected by manganese (including GABA, lactate, myo-inositol, taurine, and leucine). Enrichment analysis indicated that abnormal metabolism of glutamine and TCA circle in MHE might be affected by the ammonia, and abnormal metabolism of GABA might be affected by the Mn, and abnormal metabolism of glycolysis and branched chain amino acids metabolism might be affected by both ammonia and Mn. Both ammonia and Mn play roles in the abnormal metabolism of MHE. Chronic hypermanganese could lead to elevated blood ammonia. However, chronic hyperammonemia could not lead to brain Mn deposition.
Assuntos
Encefalopatia Hepática , Hiperamonemia , Ratos , Animais , Encefalopatia Hepática/diagnóstico , Glutamina/metabolismo , Manganês/metabolismo , Amônia/metabolismo , Isoleucina , Leucina/metabolismo , Citrulina/metabolismo , Ratos Sprague-Dawley , Encéfalo/metabolismo , Ácido Glutâmico/metabolismo , Alanina/metabolismo , Ácido gama-Aminobutírico/metabolismo , Taurina/metabolismo , Ácido Láctico/metabolismo , Hiperamonemia/metabolismo , Metabolômica , Arginina/metabolismo , Inositol/metabolismoRESUMO
Glutamine (Gln) is the most widely acting and abundant amino acid in the body and has anti-inflammatory properties, regulates body metabolism, and improves immune function. However, the mechanism of Glns effect on hyperoxic lung injury in neonatal rats is unclear. Therefore, this work focused on examining Glns function in lung injury of newborn rats mediated by hyperoxia and the underlying mechanism. We examined body mass and ratio of wet-to-dry lung tissue weights of neonatal rats. Hematoxylin and eosin (HE) staining was performed to examine histopathological alterations of lung tissues. In addition, enzyme-linked immunoassay (ELISA) was conducted to measure pro-inflammatory cytokine levels within bronchoalveolar lavage fluid (BALF). Apoptosis of lung tissues was observed using TUNEL assay. Western blotting was performed for detecting endoplasmic reticulum stress (ERS)-associated protein levels. The results showed that Gln promoted body weight gain, significantly reduced pathological damage and oxidative stress in lung tissue, and improved lung function in neonatal rats. Gln reduced pro-inflammatory cytokine release as well as inflammatory cell production in BALF and inhibited apoptosis in lung tissue cells. Furthermore, we found that Gln could downregulate ERS-associated protein levels (GRP78, Caspase-12, CHOP) and inhibit c-Jun N-terminal kinase (JNK) and inositol-requiring enzyme 1 alpha (IRE1α) phosphorylation. These results in an animal model of bronchopulmonary dysplasia (BPD) suggest that Gln may have a therapeutic effect on BPD by reducing lung inflammation, oxidative stress, and apoptosis and improving lung function; its mechanism of action may be related to the inhibition of the IRE1α/JNK pathway. (AU)
Assuntos
Animais , Ratos , Lesão Pulmonar/tratamento farmacológico , Lesão Pulmonar/etiologia , Lesão Pulmonar/prevenção & controle , Hiperóxia/complicações , Hiperóxia/metabolismo , Hiperóxia/patologia , Apoptose , Citocinas , Glutamina/metabolismo , Inflamação , Proteínas Serina-Treonina Quinases/metabolismo , Estresse Oxidativo , Pulmão/metabolismoRESUMO
Mitochondrial dysfunction can arise from genetic defects or environmental exposures and impact a wide range of biological processes. Among these are metabolic pathways involved in glutamine catabolism, anabolism, and glutamine-glutamate cycling. In recent years, altered glutamine metabolism has been found to play important roles in the pathologic consequences of mitochondrial dysfunction. Glutamine is a pleiotropic molecule, not only providing an alternate carbon source to glucose in certain conditions, but also playing unique roles in cellular communication in neurons and astrocytes. Glutamine consumption and catabolic flux can be significantly altered in settings of genetic mitochondrial defects or exposure to mitochondrial toxins, and alterations to glutamine metabolism appears to play a particularly significant role in neurodegenerative diseases. These include primary mitochondrial diseases like Leigh syndrome (subacute necrotizing encephalopathy) and MELAS (mitochondrial myopathy with encephalopathy, lactic acidosis, and stroke-like episodes), as well as complex age-related neurodegenerative disorders such as Alzheimer's and Parkinson's diseases. Pharmacologic interventions targeting glutamine metabolizing and catabolizing pathways appear to provide some benefits in cell and animal models of these diseases, indicating glutamine metabolism may be a clinically relevant target. In this review, we discuss glutamine metabolism, mitochondrial disease, the impact of mitochondrial dysfunction on glutamine metabolic processes, glutamine in neurodegeneration, and candidate targets for therapeutic intervention.
Assuntos
Síndrome MELAS , Doenças Mitocondriais , Doenças Neurodegenerativas , Animais , Glutamina/metabolismo , Glutamina/uso terapêutico , Síndrome MELAS/tratamento farmacológico , Síndrome MELAS/genética , Mitocôndrias/metabolismo , Doenças Neurodegenerativas/metabolismo , Doenças Mitocondriais/metabolismoRESUMO
We investigate the physicochemical effects of pyroglutamination on the QHALTSV-NH2 peptide, a segment of cytosolic helix 8 of the human C-X-C chemokine G-protein-coupled receptor type 4 (CXCR4). This modification, resulting from the spontaneous conversion of glutamine to pyroglutamic acid, has significant impacts on the physicochemical features of peptides. Using a static approach, we compared the transformation in different conditions and experimentally found that the rate of product formation increases with temperature, underscoring the need for caution during laboratory experiments to prevent glutamine cyclization. Circular dichroism experiments revealed that the QHALTSV-NH2 segment plays a minor role in the structuration of H8 CXCR4; however, its pyroglutaminated analogue interacts differently with its chemical environment, showing increased susceptibility to solvent variations compared to the native form. The pyroglutaminated analogue exhibits altered behavior when interacting with lipid models, suggesting a significant impact on its interaction with cell membranes. A unique combination of atomic force microscopy and infrared nanospectroscopy revealed that pyroglutamination affects supramolecular self-assembly, leading to highly packed molecular arrangements and a crystalline structure. Moreover, the presence of pyroglumatic acid has been found to favor the formation of amyloidogenic aggregates. Our findings emphasize the importance of considering pyroglutamination in peptide synthesis and proteomics and its potential significance in amyloidosis.
Assuntos
Amiloidose , Glutamina , Humanos , Peptídeos , Quimiocinas/química , Membrana Celular/metabolismo , Dicroísmo Circular , Receptores CXCR4/metabolismoRESUMO
The complete treatment of high grade invasive glioblastoma (GBM) remains to be a great challenge, and it is of great importance to develop innovative therapeutic approaches. Herein, we found that GBM derived from U87 MG cells is a glutamine-addiction tumor, and jointly using glutamine-starvation therapy and photo-enhanced chemodynamic therapy (CDT) can significantly boost its therapy. We rationally fabricated tumor cell membrane coated Cu2-xSe nanoparticles (CS NPs) and an inhibitor of glutamine metabolism (Purpurin) for combined therapy, because glutamine rather than glucose plays a crucial role in the proliferation and growth of GBM cells, and serves as a precursor for the synthesis of glutathione (GSH). The resultant CS-P@CM NPs can be specifically delivered to the tumor site to inhibit glutamine metabolism in tumor cells, suppress tumor intracellular GSH, and increase H2O2 content, which benefit the CDT catalyzed by CS NPs. The cascade reaction can be further enhanced by irradiation with the second near-infrared (NIR-II) light at the maximum concentration of H2O2, which can be monitored by photoacoustic imaging. The NIR-II light irradiation can generate a large amount of reactive oxygen species (ROS) within a short time to kill tumor cells and enhance the CDT efficacy. This is the first work on the treatment of orthotopic malignant GBM through combined glutamine metabolism therapy and photo-enhanced CDT, and provides insights into the treatment of other solid tumors by modulating the metabolism of tumor cells.
Assuntos
Glioblastoma , Nanopartículas , Neoplasias , Humanos , Glioblastoma/tratamento farmacológico , Glutamina , Peróxido de Hidrogênio , Membrana Celular , Glucose , Glutationa , Linhagem Celular Tumoral , Microambiente TumoralRESUMO
Potential associations between the risk of neurodegenerative diseases and circulating levels of amino acids have been implied in both experimental research and observational studies. However, because of the confounding and reverse causality, the findings could be biased. We aimed to determine whether circulating amino acid levels have potential effects on the risk of neurodegenerative diseases through a more robust analysis. So, we performed a total of two MR analyses, a discovery two-sample MR analysis, and a replication test, using summary-level genome-wide association study (GWAS) data, both with circulating levels of amino acids as exposure and risk of neurodegenerative diseases as an outcome. The potential causalities between nine amino acids (Glutamine [Glu], Leucine [Leu], Isoleucine [Ile], Phenylalanine [Phe], Valine [Val], Alanine [Ala], Tyrosine [Tyr], Histidine [His], and Glycine [Gly]) and six neurodegenerative disorders (Alzheimer's disease [AD], Parkinson's disease [PD], Multiple sclerosis [MS], Frontotemporal dementia [FTD], Lewy body dementia [DLB], Amyotrophic lateral sclerosis [ALS]) were explored in this study. According to the discovery MR analysis, 1 SD. increase in circulating levels of Gln was genetically determined to result in a 13% lower risk of AD (IVW ORSD [95% CI] = 0.872 [0.822, 0.926]; FDR = 7.46 × 10-5 ) while PD risk was decreased to 63% per SD. increase of circulating Leu levels (IVW ORSD [95% CI] = 0.628 [0.467, 0.843]; FDR = 0.021). Results from the replication test provide further evidence of the potential association between circulating Gln levels and AD risk (IVW ORSD [95% CI] = 0.094 [0.028, 0.311]; FDR = 9.98 × 10-4 ). Meanwhile, sensitivity analysis demonstrated that the significant relationships revealed by our two-sample MR outcomes were reliable. Our analyses provided robust evidence of causal associations between circulating levels of Gln and AD risk as well as circulating Leu levels and risk of PD. However, the underlying mechanisms remain to be further investigated.
Assuntos
Doença de Alzheimer , Doença por Corpos de Lewy , Doenças Neurodegenerativas , Doença de Parkinson , Humanos , Aminoácidos/genética , Estudo de Associação Genômica Ampla , Análise da Randomização Mendeliana , Doenças Neurodegenerativas/genética , Glutamina , CausalidadeRESUMO
Arginase 1 (Arg1), the enzyme catalyzing the conversion of arginine to ornithine, is a hallmark of IL-10-producing immunoregulatory M2 macrophages. However, its expression in T cells is disputed. Here, we demonstrate that induction of Arg1 expression is a key feature of lung CD4+ T cells during mouse in vivo influenza infection. Conditional ablation of Arg1 in CD4+ T cells accelerated both virus-specific T helper 1 (Th1) effector responses and its resolution, resulting in efficient viral clearance and reduced lung pathology. Using unbiased transcriptomics and metabolomics, we found that Arg1-deficiency was distinct from Arg2-deficiency and caused altered glutamine metabolism. Rebalancing this perturbed glutamine flux normalized the cellular Th1 response. CD4+ T cells from rare ARG1-deficient patients or CRISPR-Cas9-mediated ARG1-deletion in healthy donor cells phenocopied the murine cellular phenotype. Collectively, CD4+ T cell-intrinsic Arg1 functions as an unexpected rheostat regulating the kinetics of the mammalian Th1 lifecycle with implications for Th1-associated tissue pathologies.
Assuntos
Arginase , Influenza Humana , Animais , Humanos , Camundongos , Arginase/genética , Arginase/metabolismo , Linfócitos T CD4-Positivos/metabolismo , Glutamina , Cinética , Pulmão/metabolismo , MamíferosRESUMO
BACKGROUND: This is an open-label, single-arm, single-center pilot study using 7-Tesla in vivo proton magnetic resonance spectroscopy (1H MRS) to measure brain cortical glutathione concentration at baseline before and during the use of oral fumarates as a disease-modifying therapy for multiple sclerosis. The primary endpoint of this research was the change in prefrontal cortex glutathione concentration relative to a therapy-naïve baseline after one year of oral fumarate therapy. METHODS: Brain glutathione concentrations were examined by 1H MRS in single prefrontal and occipital cortex cubic voxels (2.5 × 2.5 × 2.5 cm3) before and during initiation of oral fumarate therapy (120 mg b.i.d. for 7 days and 240 mg b.i.d. thereafter). Additional measurements of related metabolites glutamate, glutamine, myoinositol, total N-acetyl aspartate, and total choline were also acquired in voxels centered on the same regions. Seven relapsing-remitting multiple sclerosis patients (4 f / 3 m, age range 28-50 years, mean age 40 years) naïve to fumarate therapy were scanned at pre-therapy baseline and after 1, 3, 6 and 12 months of therapy. A group of 8 healthy volunteers (4 f / 4 m, age range 33-48 years, mean age 41 years) was also scanned at baseline and Month 6 to characterize 1H-MRS measurement reproducibility over a comparable time frame. RESULTS: In the multiple sclerosis cohort, general linear models demonstrated a significant positive linear relationship between prefrontal glutathione and time either linearly across all time points (+0.05 ± 0.02 mM/month, t(27) = 2.6, p = 0.02) or specifically for factor variable Month 12 (+0.6 ± 0.3 mM/12 months, t(24) = 2.2, p = 0.04) relative to baseline. No such effects of time on glutathione concentration were demonstrated in the occipital cortex or in the healthy volunteer group. Changes in occipital total choline were further observed in the multiple sclerosis cohort as well as prefrontal total choline and occipital glutamine and myoinositol in the control cohort throughout the study duration. CONCLUSIONS: While the open-label single-arm pilot study design and abbreviated control series cannot support firm conclusions about the influence of oral fumarate therapy independent of test-retest factors or normal biological variation in a state of either health or disease, these results do justify further investigation at a larger scale into the potential relationship between prefrontal cortex glutathione increases and oral fumarate therapy in relapsing-remitting multiple sclerosis.
