Gluconeogenesis Pathway Research Articles

Paternal High-Fat Diet Altered Sperm 5'tsRNA-Gly-GCC Is Associated With Enhanced Gluconeogenesis in the Offspring.

Background: Paternal lifestyle, stress and environmental exposures play a crucial role in the health of offspring and are associated with non-genetic inheritance of acquired traits, however the underlying mechanisms are unclear. In this study, we aimed to find out how the sperm tsRNA involved in paternal high-fat diet induced abnormal gluconeogenesis of F1 offspring, and explore the underlying molecular mechanism of its regulation. Method: We generated a paternal high fat diet (42% kcal fat) model to investigate the mechanism by which paternal diet affects offspring metabolism. Four-week-old C57BL/6J male mice were randomly assigned into two groups to receive either a control diet (CD; 10% kcal fat) or a high-fat (HFD; 42% kcal fat) diet for 10 weeks, and mice from each group were then mated with 8-week-old females with control diet in a 1:2 ratio to generate F1. F0 sperms were isolated and small RNAs was sequenced by high-throughput sequencing. Metabolic phenotypes were examined with both F0 and F1. Results: A significant increase in body weight was observed with HFD-F0 mice at 8 weeks of age as compared to CD mice at the same age. F0 mice showed impaired glucose tolerance (GTT), resistance to insulin tolerance (ITT) and increased pyruvate tolerance (PTT) at 14 weeks. HFD-F1 male mice showed no significant difference in body weight. An increase in PTT was found at 13 weeks of age and no significant changes in GTT and ITT. PEPCK and G6Pase that related to gluconeogenesis increased significantly in the liver of HFD-F1 male mice. Sperm sequencing results showed that 5′tsRNA-Gly-GCC derived from tRNA-Gly-GCC-2 specifically was remarkably upregulated in sperm of HFD F0 mice. Q-PCR further showed that this tsRNA was also increased in the liver of HFD-F1 comparison with CD-F1 mice. In addition, we found that 5′tsRNA-Gly-GCC can regulate Sirt6-FoxO1 pathway and be involved in the gluconeogenesis pathway in liver. Conclusion: 5′tsRNA-Gly-GCC that increased in HFD mice mature sperms can promote gluconeogenesis in liver by regulating Sirt6-FoxO1 pathway, which might represent a potential paternal epigenetic factor mediating the intergenerational inheritance of diet-induced metabolic alteration.

Feedlot diets containing different starch levels and additives change the cecal proteome involved in cattle\u2019s energy metabolism and inflammatory response

Diets for feedlot cattle must be a higher energy density, entailing high fermentable carbohydrate content. Feed additives are needed to reduce possible metabolic disorders. This study aimed to analyze the post-rumen effects of different levels of starch (25%, 35%, and 45%) and additives (monensin or a blend of essential oils and exogenous α-amylase) in diets for Nellore feedlot cattle. The cecum tissue proteome was analyzed via two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) and then differentially expressed protein spots were identified with liquid chromatography–tandem mass spectrometry (LC–MS/MS). The use of blends of essential oils associated with α-amylase as a feed additive promoted the upregulation of enzymes such as triosephosphate isomerase, phosphoglycerate mutase, alpha-enolase, beta-enolase, fructose-bisphosphate aldolase, pyruvate kinase, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), l-lactate dehydrogenase B, l-lactate dehydrogenase A chain, l-lactate dehydrogenase, and ATP synthase subunit beta, which promote the degradation of carbohydrates in the glycolysis and gluconeogenesis pathways and oxidative phosphorylation, support pyruvate metabolism through the synthesis of lactate from pyruvate, and participate in the electron transport chain, producing ATP from ADP in the presence of a proton gradient across the membrane. The absence of proteins related to inflammation processes (leukocyte elastase inhibitors) in the cecum tissues of animals fed essential oils and amylase may be because feed enzymes can remain active in the intestine and aid in the digestion of nutrients that escape rumen fermentation; conversely, the effect of monensin is more evident in the rumen and less than 10% results in post-ruminal action, corroborating the hypothesis that ionophore antibiotics have a limited effect on the microbiota and intestinal fermentation of ruminants. However, the increase in starch in these diets promoted a downregulation of enzymes linked to carbohydrate degradation, probably caused by damage to the cecum epithelium due to increased responses linked to inflammatory injuries.

Decreased Renal Gluconeogenesis Is a Hallmark of Chronic Kidney Disease.

CKD is associated with alterations of tubular function. Renal gluconeogenesis is responsible for 40% of systemic gluconeogenesis during fasting, but how and why CKD affects this process and the repercussions of such regulation are unknown. We used data on the renal gluconeogenic pathway from more than 200 renal biopsies performed on CKD patients and from 43 kidney allograft patients, and studied three mouse models, of proteinuric CKD (POD-ATTAC), of ischemic CKD, and of unilateral urinary tract obstruction. We analyzed a cohort of patients who benefitted from renal catheterization and a retrospective cohort of patients hospitalized in the intensive care unit. Renal biopsies of CKD and kidney allograft patients revealed a stage-dependent decrease in the renal gluconeogenic pathway. Two animal models of CKD and one model of kidney fibrosis confirm gluconeogenic downregulation in injured proximal tubule cells. This shift resulted in an alteration of renal glucose production and lactate clearance during an exogenous lactate load. The isolated perfused kidney technique in animal models and renal venous catheterization in CKD patients confirmed decreased renal glucose production and lactate clearance. In CKD patients hospitalized in the intensive care unit, systemic alterations of glucose and lactate levels were more prevalent and associated with increased mortality and a worse renal prognosis at follow-up. Decreased expression of the gluconeogenesis pathway and its regulators predicted faster histologic progression of kidney disease in kidney allograft biopsies. Renal gluconeogenic function is impaired in CKD. Altered renal gluconeogenesis leads to systemic metabolic changes with a decrease in glucose and increase in lactate level, and is associated with a worse renal prognosis.

Long-Term Incubation of Lake Water Enables Genomic Sampling of Consortia Involving Planctomycetes and Candidate Phyla Radiation Bacteria.

ABSTRACTMicrobial communities in lakes can profoundly impact biogeochemical processes through their individual activities and collective interactions. However, the complexity of these communities poses challenges, particularly for studying rare organisms such as Candidate Phyla Radiation bacteria (CPR) and enigmatic entities such as aster-like nanoparticles (ALNs). Here, a reactor was inoculated with water from Lake Fargette, France, and maintained under dark conditions at 4°C for 31 months and enriched for ALNs, diverse Planctomycetes, and CPR bacteria. We reconstructed draft genomes and predicted metabolic traits for 12 diverse Planctomycetes and 9 CPR bacteria, some of which are likely representatives of undescribed families or genera. One CPR genome representing the little-studied lineage “Candidatus Peribacter” was curated to completion (1.239 Mbp) and unexpectedly encodes the full gluconeogenesis pathway. Metatranscriptomic data indicate that some planctomycetes and CPR bacteria were active under the culture conditions, accounting for ∼30% and ∼1% of RNA reads mapping to the genome set, respectively. We also reconstructed genomes and obtained transmission electron microscope images for numerous viruses, including one with a >300-kbp genome and several predicted to infect Planctomycetes. Together, our analyses suggest that freshwater Planctomycetes are central players in a subsystem that includes ALNs, symbiotic CPR bacteria, and viruses.IMPORTANCE Laboratory incubations of natural microbial communities can aid in the study of member organisms and their networks of interaction. This is particularly important for understudied lineages for which key elements of basic biology are still emerging. Using genomics and microscopy, we found that members of the bacterial lineage Planctomycetes may be central players in a subset of a freshwater lake microbiome that includes other bacteria, archaea, viruses, and mysterious entities, called aster-like nanoparticles (ALNs), whose origin is unknown. Our results help constrain the possible origins of ALNs and provide insight into possible interactions within a complex lake ecosystem.

Structural characterization of an L-fuculose-1-phosphate aldolase from Klebsiella pneumoniae

Fuculose phosphate aldolases play an important role in glycolysis and gluconeogenesis pathways. L-fuculose 1-phosphate aldolase catalyzes the reversible cleavage of L-fuculose 1-phosphate to DHAP and L-lactaldehyde. Class II aldolases found in bacteria are linked to pathogenesis of human pathogens, and have potential applications in the biosynthesis of carbohydrates and other chiral compounds. Here we report the structure of a putative L-fuculose 1-phosphate aldolase (KpFucA) from the nosocomial pathogen Klebsiella pneumoniae to 1.85 Å resolution. The enzyme crystallizes in space group P422 with one monomer per asymmetric unit. Analytical ultracentrifugation analysis confirms that KpFucA is a tetramer in solution. A magnesium ion cofactor and sulfate ion were identified in the active pocket. Enzyme activity assays confirmed that KpFcuA has a strong preference for L-fuculose 1-phosphate as a substrate, but can also catalyze the cleavage of fructose-1,6-bisphosphate and glucose-6-phosphate. This work should provide a starting point for further investigation of the role of KpFucA in K. pneumoniae pathogenesis or in industrial applications.

Molecular cloning of AKT1 and AKT2 and their divergent responses to insulin and glucose at transcriptional level in the liver of Japanese flounder Paralichthys olivaceus

The serine-threonine kinase AKT (protein kinase B) plays a vital role in insulin-mediated signaling transduction in mammals, but its role in carnivorous fish is still unclear. In the present study, AKT1 and AKT2 were cloned from Japanese flounder (Paralichthys olivaceus), and the full-length sequences of cDNA of AKT1 and AKT2 were 2335 bp and 3340 bp, encoding 473 and 482 amino acids, respectively. Tissue distribution results showed that AKT1 was most abundantly expressed in gill, intermediate in liver, spleen and brain. AKT2 was most highly expressed in liver, followed by gill, brain and eye. Compared with those intraperitoneally injected with phosphate buffer solution (PBS), after injected with 4 IU/kg of bovine insulin or 0.6 g/kg of glucose, the insulin-mediated insulin receptor (IR) / insulin receptor substrate (IRS) / phosphoinositide 3-kinase (PI3K) /AKT pathway and its downstream glucose metabolism pathways in the liver of Japanese flounder were significantly activated. AKT2 expression was significantly increased after insulin or glucose injection, but AKT1 not. Similar results were also found in the primary hepatocytes of Japanese flounder after 24-hour incubation with different doses of bovine insulin (50 nM, 100 nM and 200 nM) or PBS (Control). Knockdown of AKT2 in the hepatocytes of Japanese flounder inhibited glycolysis, glucose transport and glycogen synthesis. Meanwhile, knockdown of AKT2 promoted the phosphoenolpyruvate carboxykinase (PEPCK) expression and inhibited the glucose-6-phosphatase (G6P) expression in the gluconeogenesis pathway. It was confirmed in the present study that AKT2 was more sensitive to the insulin-mediated pathway than AKT1 in the liver of Japanese flounder after insulin or glucose administration. In addition, the glucose metabolism pathways could be mediated by AKT2 in the liver of Japanese flounder.

Annotation of glycolysis, gluconeogenesis, and trehaloneogenesis pathways provide insight into carbohydrate metabolism in the Asian citrus psyllid.

Citrus greening disease is caused by the pathogen Candidatus Liberibacter asiaticus and transmitted by the Asian citrus psyllid, Diaphorina citri. No curative treatment or significant prevention mechanism exists for this disease, which causes economic losses from reduced citrus production. A high-quality genome of D. citri is being manually annotated to provide accurate gene models to identify novel control targets and increase understanding of this pest. Here, we annotated 25 D. citri genes involved in glycolysis and gluconeogenesis, and seven in trehaloneogenesis. Comparative analysis showed that glycolysis genes in D. citri are highly conserved but copy numbers vary. Analysis of expression levels revealed upregulation of several enzymes in the glycolysis pathway in the thorax, consistent with the primary use of glucose by thoracic flight muscles. Manually annotating these core metabolic pathways provides accurate genomic foundation for developing gene-targeting therapeutics to control D. citri.

Combination Therapy with GABA and MgSO4 Improves Insulin Sensitivity in Type 2 Diabetic Rat.

Background Gamma-aminobutyric acid (GABA) and magnesium sulfate (MgSO4) play a crucial role in glycemic control. Therefore, we studied the effect of combination therapy with GABA and MgSO4 to improve insulin sensitivity in diabetes induced by streptozotocin as well as high-fat diet in a diabetic rat model. Design and Methods. Forty randomly selected rats were assigned to four groups: nondiabetic control group was fed the normal diet, insulin-resistant diabetic rat model was induced by streptozotocin and high-fat diet, GABA + MgSO4 group received GABA and MgSO4, and insulin group was treated with insulin. Body weight, abdominal fat, blood glucose, serum insulin, and glucagon concentration were measured. The glucose clamp technique, glucose tolerance test, and insulin tolerance test were performed to study insulin sensitivity. Also, the expressions of glucose 6 phosphatase, glucagon receptor, and phosphoenolpyruvate carboxykinase genes in liver were assessed for the gluconeogenesis pathway. Protein translocation and glucose transporter 4 (Glut4) genes expression in muscle were also assessed. Results Combination of GABA + MgSO4 or insulin therapy enhanced insulin level, glycemic control, glucose and insulin tolerance test, some enzymes expression in the gluconeogenesis pathway, body fat, body weight, and glucagon receptor in diabetic rats. Moreover, an increase was observed in protein and gene expression of Glut4. Insulin sensitivity in combination therapy was more than the insulin group. Conclusions GABA and MgSO4 enhanced insulin sensitivity via increasing Glut4 and reducing the gluconeogenesis enzyme and glucagon receptor gene expressions.

Zika Virus Infection of Sertoli Cells Alters Protein Expression Involved in Activated Immune and Antiviral Response Pathways, Carbohydrate Metabolism and Cardiovascular Disease.

Zika virus (ZIKV), a re-emerging virus, causes congenital brain abnormalities and Guillain–Barré syndrome. It is mainly transmitted by Aedes mosquitoes, but infections are also linked to sexual transmissions. Infectious ZIKV has been isolated, and viral RNA has been detected in semen over a year after the onset of initial symptoms, but the mode of long-term persistence is not yet understood. ZIKV can proliferate in human Sertoli cells (HSerC) for several weeks in vitro, suggesting that it might be a reservoir for persistent ZIKV infection. This study determined proteomic changes in HSerC during ZIKV infections by TMT-mass spectrometry analysis. Levels of 4416 unique Sertoli cell proteins were significantly altered at 3, 5, and 7 days after ZIKV infection. The significantly altered proteins include enzymes, transcription regulators, transporters, kinases, peptidases, transmembrane receptors, cytokines, ion channels, and growth factors. Many of these proteins are involved in pathways associated with antiviral response, antigen presentation, and immune cell activation. Several immune response pathway proteins were significantly activated during infection, e.g., interferon signaling, T cell receptor signaling, IL-8 signaling, and Th1 signaling. The altered protein levels were linked to predicted activation of immune response in HSerC, which was predicted to suppress ZIKV infection. ZIKV infection also affected the levels of critical regulators of gluconeogenesis and glycolysis pathways such as phosphoglycerate mutase, phosphoglycerate kinase, and enolase. Interestingly, many significantly altered proteins were associated with cardiac hypertrophy, which may induce heart failure in infected patients. In summary, our research contributes to a better understanding of ZIKV replication dynamics and infection in Sertoli cells.

A systematic analysis of molecular mechanisms in non-metastatic renal cancer delineates affected regulatory pathways and genes in tumor growth.

In the recent century, Kidney cancer has emerged as one of the critical renal diseases. Therefore, we analyzed gene expression profiles of non-metastatic kidney cancer to find mechanisms associated with the early-stage pathogenesis of the disease. We concentrated on the most dysregulated genes in expression to discover possible unknown proliferative molecular mechanisms and oncogenic pathways promoting kidney renal cancer growth. Survival analysis, expression profiling, and gene set over-representation analysis were conducted on the most upregulated and most down-regulated genes alongside the hub genes. Our results demonstrated that pathways engaged in the metabolism of amino acids and carbohydrates and those involved in peroxisome organization were shown to be important in developing benign tumors. Furthermore, upregulation of genes such as CXCL9 and 10 genes and CXCR4 in chemokine response pathways would bolster differentiation and engagement of immune cells in the tumor microenvironment. C3, one of the essential members of the complement system, with a high degree and betweenness centrality in the PPI network, upregulated significantly not only in our analysis but also in the validation expression profiling results and survival analysis. We also identified genes such as TYROBP, ITGB2, and EGFR to be engaged in both immunological pathways and superoxide pathways. Furthermore, we found that downregulation of Aldolase B engaged in Glycolysis and Gluconeogenesis pathways would help develop benign tumors. Finally, many top hub genes, including TYMS, PTPRC, AURKA, FN1, UBE2C, and CD53 were proposed to be engaged in the progression of non-metastatic renal tumors. This holistic interrogation calls attention to investigate further and experimentally validate the proposed molecular mechanisms.

Daidzin inhibits hepatocellular carcinoma survival by interfering with the glycolytic/gluconeogenic pathway through downregulation of TPI1.

Daidzin (DDZ) is a natural brassin-like compound extracted from the soybean, and has been found to have therapeutic potential against tumors in recent years. This study investigates the therapeutic effect of DDZ on hepatocellular carcinoma cells and elucidates the possible mechanisms of action. The viability of HCCLM3 and Hep3B cells was detected by MTT assay. Western blots and qPCR were used to detect the protein and mRNA levels of proliferation and apoptosis related genes. Gas chromatography-mass spectrometry (GC-MS) was used for metabolome analysis. In vivo antitumor effects were assessed in nude mice engrafted with HCC cell lines. Our results show that DDZ treatment dose-dependently inhibited cell viability, migration, and survival. The expressions of CDK1, BCL2, MYC, and survivin were reduced, while the expressions of BAX and PARP were increased in DDZ treated cells. The differentially expressed metabolites detected in DDZ treated cultures are associated with glycolysis/gluconeogenesis pathways. Bioinformatic analysis identified TPI1, a gene in the glycolysis pathway with prognostic value for hepatocellular carcinoma (HCC), and DDZ treatment downregulated this gene. In vivo experiments show that DDZ significantly reduced the tumor volume and weight, and inhibited Ki67 expression within tumors. This study shows that DDZ interfered with the survival and migration of hepatocellular carcinoma cells, likely via TPI1 and the gluconeogenesis pathway.

Design, synthesis and structural-activity relationship studies of phanginin A derivatives for regulating SIK1-cAMP/CREB signaling to suppress hepatic gluconeogenesis

Persistent activation of hepatic gluconeogenesis is a main cause of fasting hyperglycemia in patients with type 2 diabetes (T2D), and the salt-induced kinase 1 (SIK1) acts as a key modulator in regulating hepatic gluconeogenesis. Recently, we first reported phanginin A (PA, 1), a natural cassane diterpenoid isolated from the seeds of Caesalpinia sappan, exhibited potent anti-diabetic effect through activation of SIK1 and increasing PDE4 activity to inhibit hepatic gluconeogenesis pathway by suppressing the cAMP/PKA/CREB pathway in the liver. In present study, we designed and prepared 25 PA derivatives and their structure−activity relationship (SAR) for gluconeogenesis inhibitory activity were established. Among them, compound 7 exhibited remarkable inhibitory activity on hepatic gluconeogenesis by enhancing the SIK1 phosphorylation and ameliorated the hyperglyceamia of type 2 diabetic mice. Our results supported that compound 7 could be served as a potential candidate for the treatment of T2D.

Multi-Omics Profiling Identifies Pathways Associated With CD8+ T-Cell Activation in Severe Aplastic Anemia.

Severe aplastic anemia (SAA) is an autoimmune disease characterized by immune-mediated destruction of hematopoietic stem and progenitor cells. Autoreactive CD8+ T cells have been reported as the effector cells; however, the mechanisms regulating their cell activation in SAA remain largely unknown. Here, we performed proteomics and metabolomics analyses of plasma and bone marrow supernatant, together with transcriptional analysis of CD8+ T cells from SAA patients and healthy donors, to find key pathways that are involved in pathogenic CD8+ T-cell activation. We identified 21 differential proteins and 50 differential metabolites in SAA patients that were mainly involved in energy metabolism, complement and coagulation cascades, and HIF-1α signaling pathways. Interestingly, we found that these pathways are also enriched in T cells from SAA patients by analyzing available single-cell RNA sequencing data. Moreover, CD8+ T cells from SAA patients contain a highly activated CD38+ subset, which was increased in the bone marrow of SAA patients and a murine model of SAA. This subset presented enriched genes associated with the glycolysis or gluconeogenesis pathway, HIF-1α signaling pathway, and complement associated pathways, all of which were of importance in T-cell activation. In conclusion, our study reveals new pathways that may regulate CD8+ T-cell activation in SAA patients and provides potential therapeutic targets for SAA treatment.

Iridoid glycoside isolated from Wendlandia glabrata and the role of its enriched fraction in regulating AMPK/PEPCK/G6Pase signaling pathway of hepatic gluconeogenesis

Phytochemical investigation of W. glabrata and antihyperglycemic potential of isolated novel iridoid glycoside enriched fraction in CC1 hepatocytes and STZ-induced diabetic mice.

Genetic Potential of Dissulfurimicrobium hydrothermale, an Obligate Sulfur-Disproportionating Thermophilic Microorganism

The biochemical pathways of anaerobic sulfur disproportionation are only partially deciphered, and the mechanisms involved in the first step of S0-disproportionation remain unknown. Here, we present the results of sequencing and analysis of the complete genome of Dissulfurimicrobium hydrothermale strain Sh68T, one of two strains isolated to date known to grow exclusively by anaerobic disproportionation of inorganic sulfur compounds. Dissulfurimicrobium hydrothermale Sh68T is a motile, thermophilic, anaerobic, chemolithoautotrophic microorganism isolated from a hydrothermal pond at Uzon caldera, Kamchatka, Russia. It is able to produce energy and grow by disproportionation of elemental sulfur, sulfite and thiosulfate. Its genome consists of a circular chromosome of 2,025,450 base pairs, has a G + C content of 49.66% and a completion of 97.6%. Genomic data suggest that CO2 assimilation is carried out by the Wood–Ljungdhal pathway and that central anabolism involves the gluconeogenesis pathway. The genome of strain Sh68T encodes the complete gene set of the dissimilatory sulfate reduction pathway, some of which are likely to be involved in sulfur disproportionation. A short sequence protein of unknown function present in the genome of strain Sh68T is conserved in the genomes of a large panel of other S0-disproportionating bacteria and was absent from the genomes of microorganisms incapable of elemental sulfur disproportionation. We propose that this protein may be involved in the first step of elemental sulfur disproportionation, as S0 is poorly soluble and unable to cross the cytoplasmic membrane in this form.

More simple more worse: Simple carbohydrate diets cause alterations in glucose and lipid metabolism in Nile tilapia (Oreochromis niloticus)

Dietary carbohydrates are widely used in aquafeeds as cheap energy source and improve quality of feeds. However, comprehensive assessment of the effects of dietary carbohydrate complexity on fish metabolism and liver health is currently lacking. This study investigated the effect of replacing 50% of starch by using sucrose, fructose and glucose. Four isonitrogenic (400 g/kg protein) and isolipidic (60 g/kg fat) feeds containing starch (polysaccharide), sucrose (disaccharide) and fructose and glucose (monosaccharides) were fed to three replicates of 4.5 ± 0.30 g Nile tilapia (Oreochromis niloticus) for eight weeks. Afterwards, growth performance, feed utilization efficiency, glucose and lipid metabolism and liver health were evaluated. The results showed that the Nile tilapia fed on monosaccharide diets had significantly lower growth and feed utilization efficiency than those fed on disaccharide and polysaccharide diets. The Nile tilapia fed on monosaccharide diets reduced significantly lipid deposition, hepatosomatic index (HSI), serum alanine transaminase (ALT) and aspartate aminotransferase (AST) and expression of lipid metabolism genes than those fed on polysaccharide diet. The Nile tilapia fed on disaccharide diet increased significantly the serum insulin, muscle glycogen, and muscle glycogen synthase (gs) gene expression compared with those fed on polysaccharide diet. Interestingly, the Nile tilapia fed on monosaccharide diets reduced significantly the glycogen content while they increased insulin, glucose and the expression of liver gluconeogenesis genes such as glucose-6-phosphatase (g6pase) and phosphoenolpyruvate carboxykinase (pepck) than those fed on polysaccharide diet. Contrary, the Nile tilapia fed on disaccharide diet downregulated liver glucose catabolism and lowered serum triglyceride (TG) levels than those fed on polysaccharide but enhanced muscle peroxisome proliferator activated receptor alpha (pparα) and carnitine palmitoyltransferase 1a (cpt1a) gene expression, liver gluconeogenesis and pentose phosphate pathways. These results indicate that Nile tilapia utilizes better dietary polysaccharides and disaccharides than monosaccharides. Feeding Nile tilapia on monosaccharide diets caused insulin resistance and glucose metabolism disorders manifested by hyperinsulinism and hyperglycemia, respectively. The carbohydrate complexity affects the nutritional metabolism and liver health of fish.

Biophysical and functional properties of purified glucose-6-phosphatase catalytic subunit 1

Glucose-6-phosphatase catalytic subunit 1 (G6PC1) plays a critical role in hepatic glucose production during fasting by mediating the terminal step of the gluconeogenesis and glycogenolysis pathways. In concert with accessory transport proteins, this membrane-integrated enzyme catalyzes glucose production from glucose-6-phosphate (G6P) to support blood glucose homeostasis. Consistent with its metabolic function, dysregulation of G6PC1 gene expression contributes to diabetes, and mutations that impair phosphohydrolase activity form the clinical basis of glycogen storage disease type 1a. Despite its relevance to health and disease, a comprehensive view of G6PC1 structure and mechanism has been limited by the absence of expression and purification strategies that isolate the enzyme in a functional form. In this report, we apply a suite of biophysical and biochemical tools to fingerprint the in vitro attributes of catalytically active G6PC1 solubilized in lauryl maltose neopentyl glycol (LMNG) detergent micelles. When purified from Sf9 insect cell membranes, the glycosylated mouse ortholog (mG6PC1) recapitulated functional properties observed previously in intact hepatic microsomes and displayed the highest specific activity reported to date. Additionally, our results establish a direct correlation between the catalytic and structural stability of mG6PC1, which is underscored by the enhanced thermostability conferred by phosphatidylcholine and the cholesterol analog cholesteryl hemisuccinate. In contrast, the N96A variant, which blocks N-linked glycosylation, reduced thermostability. The methodologies described here overcome long-standing obstacles in the field and lay the necessary groundwork for a detailed analysis of the mechanistic structural biology of G6PC1 and its role in complex metabolic disorders.

Comprehensive evaluation and analysis of the salinity stress response mechanisms based on transcriptome and metabolome of Staphylococcus aureus.

Staphylococcus aureus possesses an extraordinary ability to deal with a wide range of osmotic pressure. This study performed transcriptomic and metabolomic analyses on the potential mechanism of gradient salinity stress adaptation in S. aureus ZS01. The results revealed that CPS biosynthetic protein genes were candidate target genes for directly regulating the phenotypic changes of biofilm. Inositol phosphate metabolism was downregulated to reduce the conversion of functional molecules. The gluconeogenesis pathway and histidine synthesis were downregulated to reduce the production of endogenous glucose. The pyruvate metabolism pathway was upregulated to promote the accumulation of succinate. TCA cycle metabolism pathway was downregulated to reduce unnecessary energy loss. L-Proline was accumulated to regulate osmotic pressure. Therefore, these self-protection mechanisms can protect cells from hypertonic environments and help them focus on survival. In addition, we identified ten hub genes. The findings will aid in the prevention and treatment strategies of S. aureus infections.

Bioinformatics analysis of pathways of renal infiltrating macrophages in different renal disease models.

BackgroundRecent studies have suggested that macrophages are significantly involved in different renal diseases. However, the role of these renal infiltrating macrophages has not been entirely uncovered. To further clarify the underlying mechanism and identify therapeutic targets, a bioinformatic analysis based on transcriptome profiles was performed.MethodsThree transcription profiling datasets, GSE27045, GSE51466 and GSE75808, were obtained from the Gene Expression Omnibus (GEO). Differentially expressed genes (DEGs) were assessed by Gene Ontology (GO) functional annotation, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis and gene set enrichment analysis (GSEA).ResultsThe classic signaling pathways and metabolic pathways of macrophages infiltrating the kidney in different pathophysiological processes, including lupus nephritis (LN), renal crystal formation and renal ischemia-reperfusion injury (IRI), were analysed. Furthermore, the common classical pathways significantly altered in the three renal disorders were the oxidative phosphorylation, VEGF signaling and JAK/STAT signaling pathways, while the renin-angiotensin system was uniquely altered in LN, the glycolysis and gluconeogenesis pathways were uniquely altered in models of renal crystal formation, and the calcium signaling pathway was specific to renal IRI.ConclusionsVia bioinformatics analysis, this study revealed the transcriptional features of macrophages in murine LN, renal crystal formation and IRI models, which may serve as promising targets for mechanistic research and the clinical treatment of multiple renal diseases.

GABA administration improves liver function and insulin resistance in offspring of type 2 diabetic rats

This study investigated the role of GABA in attenuating liver insulin resistance (IR) in type 2 diabetes parents and reducing its risk in their descendants’ liver. Both sexes’ rats were divided into four groups of non-diabetic control, diabetic control (DC), GABA-treated (GABA), and insulin-treated (Ins). The study duration lasted for six months and the young animals followed for four months. Consequently, hyperinsulinemic-euglycemic clamp was performed for all animals. Apart from insulin tolerance test (ITT), serum and liver lipid profile were measured in all groups. Glycogen levels, expression of Foxo1, Irs2, Akt2, and Pepck genes in the liver were assessed for all groups. Overall, GABA improved ITT, increased liver glycogen levels and decreased lipid profile, blood glucose level, and HbA1c in parents and their offspring in compared to the DC group. GIR also increased in both parents and their offspring by GABA. Moreover, the expression of Foxo1, Irs2, Akt2, and Pepck genes improved in GABA-treated parents and their descendants in compared to DC group. Results indicated that GABA reduced liver IR in both parents and their offspring via affecting their liver insulin signaling and gluconeogenesis pathways.