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Frontiers in Bioscience (Landmark... Jun 2024Under fasting conditions, the pathway converting gluconeogenesis precursors into muscle glycogen becomes crucial due to reduced glycogen reserves. However, there is...
BACKGROUND
Under fasting conditions, the pathway converting gluconeogenesis precursors into muscle glycogen becomes crucial due to reduced glycogen reserves. However, there is limited research on skeletal muscle gluconeogenesis and the impact of fasting on gluconeogenic gene expression.
METHODS
Sheep fetal skeletal muscle cells cultured were used to study the effects of varying lactic acid concentrations (0 to 30 mM) and 2.5 mM glucose on the expression of gluconeogenesis-related genes after 6 h of fasting. The effects on mRNA and protein expression of key genes involved in skeletal muscle gluconeogenesis were measured by quantitative real time polymerase chain reaction (qRT-PCR), immunofluorescence, and western blotting at 48 h.
RESULTS
Fasting increased the expression of key gluconeogenic genes, fructose-1,6-bisphosphatase 2 (), glucose-6-phosphatase 3 (), pyruvate kinase M (), monocarboxylate transporter1 (), glucose transporter type 4 (), pyruvate carboxylase (), and lactate dehydrogenase A (). The mRNA levels of , , and significantly decreased with glucose addition. Additionally, 10 mM lactic acid significantly promoted the expression of , , , , , and while inhibiting phosphoenolpyruvate carboxykinase () expression. At the protein level, 10 mM lactic acid significantly increased FBP2 and PKM protein expression.
CONCLUSIONS
This study shows that fasting regulates key gluconeogenic gene expression in sheep skeletal muscle cells and highlights the role of lactic acid in inducing these gene expressions.
Topics: Animals; Gluconeogenesis; Sheep; Muscle, Skeletal; Gene Expression Regulation; Glucose; Cells, Cultured; Lactic Acid; Fructose-Bisphosphatase
PubMed: 38940053
DOI: 10.31083/j.fbl2906237 -
Journal of Bioscience and Bioengineering Jun 2024Anaplerotic reactions catalyzed by pyruvate carboxylase (PC) and phosphoenolpyruvate carboxylase (PEPC) have important roles in the production of l-lysine to replenish...
Anaplerotic reactions catalyzed by pyruvate carboxylase (PC) and phosphoenolpyruvate carboxylase (PEPC) have important roles in the production of l-lysine to replenish oxaloacetic acid (OAA) in Corynebacterium glutamicum. However, the relative contributions of these enzymes to l-lysine production in C. glutamicum are not fully understood. In this study, using a parent strain (P) carrying a feedback inhibition-resistant aspartokinase with the T311I mutation, we constructed a PC gene-deleted mutant strain (PΔPC) and a PEPC gene-deleted mutant strain (PΔPEPC). Although the growth of both mutant strains was comparable to the growth of strain P, the maximum l-lysine production in strains PΔPC and PΔPEPC decreased by 14% and 49%, respectively, indicating that PEPC strongly contributed to OAA supply. l-Lysine production in strain PΔPC slightly decreased during the logarithmic phase, while production during the early stationary phase was comparable to production in strain P. By contrast, strain PΔPEPC produced l-lysine in an amount comparable to the production of strain P during the logarithmic phase; l-lysine production after the early stationary phase was completely stopped in strain PΔPEPC. These results indicate that OAA is supplied by both PC and PEPC during the logarithmic phase, while only PEPC can continuously supply OAA after the logarithmic phase.
PubMed: 38937154
DOI: 10.1016/j.jbiosc.2024.05.015 -
Nutrients Jun 2024Nucleotides (NTs) act as pivotal regulatory factors in numerous biological processes, playing indispensable roles in growth, development, and metabolism across...
Nucleotides (NTs) act as pivotal regulatory factors in numerous biological processes, playing indispensable roles in growth, development, and metabolism across organisms. This study delves into the effects of exogenous NTs on hepatic insulin resistance using palmitic-acid-induced HepG2 cells, administering interventions at three distinct dosage levels of exogenous NTs. The findings underscore that exogenous NT intervention augments glucose consumption in HepG2 cells, modulates the expression of glycogen-synthesis-related enzymes (glycogen synthase kinase 3β and glycogen synthase), and influences glycogen content. Additionally, it governs the expression levels of hepatic enzymes (hexokinase, phosphoenolpyruvate carboxykinase, and glucose-6-phosphatase). Moreover, exogenous NT intervention orchestrates insulin signaling pathway (insulin receptor substrate-1, protein kinase B, and forkhead box protein O1) and AMP-activated protein kinase (AMPK) activity in HepG2 cells. Furthermore, exogenous NT intervention fine-tunes the expression levels of oxidative stress-related markers (malondialdehyde, glutathione peroxidase, and NADPH oxidase 4) and the expression of inflammation-related nuclear transcription factor (NF-κB). Lastly, exogenous NT intervention regulates the expression levels of glucose transporter proteins (GLUTs). Consequently, exogenous NTs ameliorate insulin resistance in HepG2 cells by modulating the IRS-1/AKT/FOXO1 pathways and regulate glucose consumption, glycogen content, insulin signaling pathways, AMPK activity, oxidative stress, and inflammatory status.
Topics: Humans; Hep G2 Cells; Insulin Resistance; Palmitic Acid; Insulin Receptor Substrate Proteins; Forkhead Box Protein O1; Proto-Oncogene Proteins c-akt; Signal Transduction; Nucleotides; Glucose; Oxidative Stress; Glycogen; Insulin
PubMed: 38931156
DOI: 10.3390/nu16121801 -
Molecules (Basel, Switzerland) Jun 2024The phosphoenol pyruvate-oxaloacetate-pyruvate-derived amino acids (POP-AAs) comprise native intermediates in cellular metabolism, within which the phosphoenol... (Review)
Review
The phosphoenol pyruvate-oxaloacetate-pyruvate-derived amino acids (POP-AAs) comprise native intermediates in cellular metabolism, within which the phosphoenol pyruvate-oxaloacetate-pyruvate (POP) node is the switch point among the major metabolic pathways existing in most living organisms. POP-AAs have widespread applications in the nutrition, food, and pharmaceutical industries. These amino acids have been predominantly produced in and through microbial fermentation. With the rapid increase in market requirements, along with the global food shortage situation, the industrial production capacity of these two bacteria has encountered two bottlenecks: low product conversion efficiency and high cost of raw materials. Aiming to push forward the update and upgrade of engineered strains with higher yield and productivity, this paper presents a comprehensive summarization of the fundamental strategy of metabolic engineering techniques around phosphoenol pyruvate-oxaloacetate-pyruvate node for POP-AA production, including L-tryptophan, L-tyrosine, L-phenylalanine, L-valine, L-lysine, L-threonine, and L-isoleucine. Novel heterologous routes and regulation methods regarding the carbon flux redistribution in the POP node and the formation of amino acids should be taken into consideration to improve POP-AA production to approach maximum theoretical values. Furthermore, an outlook for future strategies of low-cost feedstock and energy utilization for developing amino acid overproducers is proposed.
Topics: Metabolic Engineering; Amino Acids; Oxaloacetic Acid; Escherichia coli; Phosphoenolpyruvate; Corynebacterium glutamicum; Pyruvic Acid; Metabolic Networks and Pathways; Fermentation
PubMed: 38930958
DOI: 10.3390/molecules29122893 -
International Journal of Molecular... Jun 2024During the adaptive evolution of animals, the host and its gut microbiota co-adapt to different elevations. Currently, there are few reports on the rumen...
During the adaptive evolution of animals, the host and its gut microbiota co-adapt to different elevations. Currently, there are few reports on the rumen microbiota-hepato-intestinal axis of Tibetan sheep at different altitudes. Therefore, the purpose of this study was to explore the regulatory effect of rumen microorganism-volatile fatty acids (VFAs)-VFAs transporter gene interactions on the key enzymes and genes related to gluconeogenesis in Tibetan sheep. The rumen fermentation parameters, rumen microbial densities, liver gluconeogenesis activity and related genes were determined and analyzed using gas chromatography, RT-qPCR and other research methods. Correlation analysis revealed a reciprocal relationship among rumen microflora-VFAs-hepatic gluconeogenesis in Tibetan sheep at different altitudes. Among the microbiota, (), (), and () were significantly correlated with propionic acid ( < 0.05), while propionic acid was significantly correlated with the transport genes monocarboxylate transporter 4 () and anion exchanger 2 () ( < 0.05). Propionic acid was significantly correlated with key enzymes such as pyruvate carboxylase, phosphoenolpyruvic acid carboxylase and glucose (Glu) in the gluconeogenesis pathway ( < 0.05). Additionally, the expressions of these genes were significantly correlated with those of the related genes, namely, forkhead box protein O1 () and mitochondrial phosphoenolpyruvate carboxykinase 2 () ( < 0.05). The results showed that rumen microbiota densities differed at different altitudes, and the metabolically produced VFA contents differed, which led to adaptive changes in the key enzyme activities of gluconeogenesis and the expressions of related genes.
Topics: Animals; Gluconeogenesis; Sheep; Rumen; Gastrointestinal Microbiome; Liver; Fatty Acids, Volatile; Tibet; Altitude; Adaptation, Physiological; Fermentation
PubMed: 38928432
DOI: 10.3390/ijms25126726 -
Microbiology Spectrum Jun 2024Tuberculosis (TB) is a leading cause of death among infectious diseases worldwide due to latent TB infection, which is the critical step for the successful pathogenic...
UNLABELLED
Tuberculosis (TB) is a leading cause of death among infectious diseases worldwide due to latent TB infection, which is the critical step for the successful pathogenic cycle. In this stage resides inside the host in a dormant and antibiotic-tolerant state. Latent TB infection can also lead to multisystemic diseases because invades virtually all organs, including ocular tissues. Ocular tuberculosis (OTB) occurs when the dormant bacilli within the ocular tissues reactivate, originally seeded by hematogenous spread from pulmonary TB. Histological evidence suggests that retinal pigment epithelium (RPE) cells play a central role in immune privilege and in protection from antibiotic effects, making them an anatomical niche for invading . RPE cells exhibit high tolerance to environmental redox stresses, allowing phagocytosed bacilli to maintain viability in a dormant state. However, the microbiological and metabolic mechanisms determining the interaction between the RPE intracellular environment and phagocytosed are largely unknown. Here, liquid chromatography-mass spectrometry metabolomics were used to illuminate the metabolic state within RPE cells reprogrammed to harbor dormant bacilli and enhance antibiotic tolerance. Timely and accurate diagnosis as well as efficient chemotherapies are crucial in preventing the poor visual outcomes of OTB patients. Unfortunately, the efficacy of current methods is highly limited. Thus, the results will lead to propose a novel therapeutic option to synthetically kill the dormant inside the RPE cells by modulating the phenotypic state of and laying the foundation for a new, innovative regimen for treating OTB.
IMPORTANCE
Understanding the metabolic environment within the retinal pigment epithelium (RPE) cells altered by infection with and mycobacterial dormancy is crucial to identify new therapeutic methods to cure ocular tuberculosis. The present study showed that RPE cellular metabolism is altered to foster intracellular to enter into the dormant and drug-tolerant state, thereby blunting the efficacy of anti-tuberculosis chemotherapy. RPE cells serve as an anatomical niche as the cells protect invading bacilli from antibiotic treatment. LC-MS metabolomics of RPE cells after co-treatment with HO and infection showed that the intracellular environment within RPE cells is enriched with a greater level of oxidative stress. The antibiotic tolerance of intracellular within RPE cells can be restored by a metabolic manipulation strategy such as co-treatment of antibiotic with the most downstream glycolysis metabolite, phosphoenolpyruvate.
PubMed: 38916325
DOI: 10.1128/spectrum.00788-24 -
Journal of Proteome Research Jun 2024Protein succinylation modification is a common post-translational modification (PTM) that plays an important role in bacterial metabolic regulation. In this study,...
Protein succinylation modification is a common post-translational modification (PTM) that plays an important role in bacterial metabolic regulation. In this study, quantitative analysis was conducted on the succinylated proteome of wild-type and florfenicol-resistant to investigate the mechanism of succinylation regulating antibiotic resistance. Bioinformatic analysis showed that the differentially succinylated proteins were mainly enriched in energy metabolism, and it was found that the succinylation level of phosphoenolpyruvate carboxyl kinase (PEPCK) was highly expressed in the florfenicol-resistant strain. Site-directed mutagenesis was used to mutate the lysine (K) at the succinylation site of PEPCK to glutamic acid (E) and arginine (R), respectively, to investigate the function of lysine succinylation of PEPCK in the florfenicol resistance of . The detection of site-directed mutagenesis strain viability under florfenicol revealed that the survival rate of the E mutant was significantly higher than that of the R mutant and wild type, indicating that succinylation modification of PEPCK protein may affect the resistance of to florfenicol. This study indicates the important role of PEPCK during antibiotic-resistance evolution and provides a theoretical basis for the prevention and control of vibriosis and the development of new antibiotics.
PubMed: 38904328
DOI: 10.1021/acs.jproteome.4c00085 -
International Journal of Biological... 2024Coenzyme Q (CoQ), a quinone derivative from , has antitumor capabilities. This study investigated the antitumor effect of noncytotoxic CoQ, which included NLRP3...
Coenzyme Q (CoQ), a quinone derivative from , has antitumor capabilities. This study investigated the antitumor effect of noncytotoxic CoQ, which included NLRP3 inflammasome inhibition, anti-EMT/metastasis, and metabolic reprogramming via HIF-1α inhibition, in HNSCC cells under normoxia and hypoxia. CoQ suppressed hypoxia-induced ROS-mediated HIF-1α expression in OECM-1 and SAS cells. Under normoxia and hypoxia, the inflammatory NLRP3, ASCcaspase-1, NFκB, and IL-1β expression was reduced by CoQ. CoQ reduced migration/invasion by enhancing epithelial marker E-cadherin and suppressing mesenchymal markers Twist, N-cadherin, Snail, and MMP-9, and MMP-2 expression. CoQ inhibited glucose uptake, lactate accumulation, GLUT1 levels, and HIF-1α-target gene (HK-2, PFK-1, and LDH-A) expressions that are involved in aerobic glycolysis. Notably, CoQ reduced ECAR as well as glycolysis, glycolytic capability, and glycolytic reserve and enhanced OCR, basal respiration, ATP generation, maximal respiration, and spare capacity in OECM-1 cells. Metabolomic analysis using LC-ESI-MS showed that CoQ treatment decreased the levels of glycolytic intermediates, including lactate, 2/3-phosphoglycerate, fructose 1,6-bisphosphate, and phosphoenolpyruvate, and increased the levels of TCA cycle metabolites, including citrate, isocitrate, and succinate. HIF-1α silencing reversed CoQ-mediated anti-metastasis (N-Cadherin, Snail, and MMP-9) and metabolic reprogramming (GLUT1, HK-2, and PKM-2) under hypoxia. CoQ prevents cancer stem-like characteristics (upregulated CD24 expression and downregulated CD44, ALDH1, and OCT4) under normoxia and/or hypoxia. Further, in IL-6-treated SG cells, CoQ attenuated fibrosis by inhibiting TGF-β and Collagen I expression and suppressed EMT by downregulating Slug and upregulating E-cadherin expression. Interesting, CoQ inhibited the growth of OECM-1 tumors in xenografted mice. Our results advocate CoQ for the therapeutic application against HNSCC.
Topics: Humans; NLR Family, Pyrin Domain-Containing 3 Protein; Hypoxia-Inducible Factor 1, alpha Subunit; Cell Line, Tumor; Epithelial-Mesenchymal Transition; Ubiquinone; Animals; Squamous Cell Carcinoma of Head and Neck; Mice; Inflammasomes; Warburg Effect, Oncologic; Mice, Nude; Head and Neck Neoplasms
PubMed: 38904007
DOI: 10.7150/ijbs.93943 -
Biomedicine & Pharmacotherapy =... Jun 2024To delve into the underlying mechanism of Salidroside (Sal) on the improvement of cognitive function in Parkinson's Disease (PD).
OBJECTIVE
To delve into the underlying mechanism of Salidroside (Sal) on the improvement of cognitive function in Parkinson's Disease (PD).
METHODS
The experimental mice were divided into Control group, Model group [injected with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)], and Model+Sal (low concentration, high concentration) group. Mouse hippocampal tissues were extracted for RNA sequencing to obtain the core pathway and core gene. Mouse plasma was prepared and analyzed by LC-MS to obtain differential metabolites. In vitro experiments were verified by immunofluorescence and lentiviral transduction.
RESULTS
ELISA signaled that Sal facilitated the reduction of neuronal damage and inflammatory reaction in mice. MPTP_Sal_Low and MPTP_Sal_High groups had high levels of glial cell derived neurotrophie factor (GDNF) expression. Differentially expressed genes (DEGs) in control group, MPTP group and MPTP_Sal_High group were identified by transcriptomic, which were classified to the mitogen-activated protein kinase (MAPK) signaling pathway, and the core gene Braf was obtained. Metabolomics manifested that the differential metabolites involved DL-tyrosine, adenosine, phosphoenolpyruvate, and L-tryptophan. In vitro experiments verified that Sal treatment inhibited the up-regulation of p-p38, p-c-Jun N-terminal kinase (JNK), and p-extracellular signal-regulated kinase (ERK) expression, and growth of neuronal protrusions. The OE-Braf group showed a significant up-regulation of the GDNF expression, a decrease in the expression of p-p38, p-JNK, and p-ERK, and a significant growth of neuronal protrusions.
CONCLUSION
Sal may exert its effects in PD through the Braf-mediated MAPK signaling pathway, which can increase GDNF expression and promote neuronal protrusion growth for the protection of neurological function and the improvement of cognitive function.
PubMed: 38901199
DOI: 10.1016/j.biopha.2024.116968 -
Current Microbiology Jun 2024Pyruvate (Pyr) is the end product of the glycolysis pathway. Pyr is also renewable and is further metabolized to produce formate, which is the precursor of H, via...
Pyruvate (Pyr) is the end product of the glycolysis pathway. Pyr is also renewable and is further metabolized to produce formate, which is the precursor of H, via pyruvate formate lyase (PFL) under anaerobic conditions. The formate is excluded and re-imported via the formate channel and is then converted to H via the formate hydrogenlyase (FHL) complex. In H producing marine vibrios, such as Vibrio tritonius and Vibrio porteresiae in the Porteresiae clade of the family Vibrionaceae, apparent but inefficient H production from Pyr has been observed. To elucidate the molecular mechanism of why this inefficient H production is observed in Pry-metabolized marine vibrio cells and how glycolysis affects those H productions of marine vibrios, the "Core Transcriptome" approach to find common gene expressions of those two major H producing Vibrio species in Pyr metabolism was first applied. In the Pyr-metabolized vibrio cells, genes for the "Phosphoenolpyruvate (PEP)-Pyruvate-Oxalate (PPO)" node, due to energy saving, and PhoB-, RhaR-, and DeoR-regulons were regulated. Interestingly, a gene responsible for oxalate/formate family antiporter was up-regulated in Pyr-metabolized cells compared to those of Glc-metabolized cells, which provides new insights into the uses of alternative formate exclusion mechanics due to energy deficiencies in Pyr-metabolized marine vibrios cells. We further discuss the contribution of the Embden-Meyerhof-Parnas (EMP) pathway to efficient H production in marine vibrios.
Topics: Hydrogen; Vibrio; Transcriptome; Glycolysis; Pyruvic Acid; Bacterial Proteins; Seawater; Gene Expression Regulation, Bacterial; Aquatic Organisms
PubMed: 38896159
DOI: 10.1007/s00284-024-03764-z