Aldolase B (ALDOB), a glycolytic enzyme, is uniformly depleted in clear cell renal cell carcinoma (ccRCC) tissues. We previously showed that ALDOB inhibited proliferation through a mechanism independent of its enzymatic activity in ccRCC, but the mechanism was not unequivocally identified. We showed that the corepressor C-terminal-binding protein 2 (CtBP2) is a novel ALDOB-interacting protein in ccRCC. The CtBP2-to-ALDOB expression ratio in clinical samples was correlated with the expression of CtBP2 target genes and was associated with shorter survival. ALDOB inhibited CtBP2-mediated repression of multiple cell cycle inhibitor, proapoptotic, and epithelial marker genes. Furthermore, ALDOB overexpression decreased the proliferation and migration of ccRCC cells in an ALDOB-CtBP2 interaction-dependent manner. Mechanistically, our findings showed that ALDOB recruited acireductone dioxygenase 1, which catalyzes the synthesis of an endogenous inhibitor of CtBP2, 4-methylthio 2-oxobutyric acid. ALDOB functions as a scaffold to bring acireductone dioxygenase and CtBP2 in close proximity to potentiate acireductone dioxygenase-mediated inhibition of CtBP2, and this scaffolding effect was independent of ALDOB enzymatic activity. Moreover, increased ALDOB expression inhibited tumor growth in a xenograft model and decreased lung metastasis in vivo. Our findings reveal that ALDOB is a negative regulator of CtBP2 and inhibits tumor growth and metastasis in ccRCC.
Humans ; Carcinoma, Renal Cell/genetics* ; Fructose-Bisphosphate Aldolase/metabolism* ; Co-Repressor Proteins/metabolism* ; Transcription Factors/genetics* ; Kidney Neoplasms/genetics* ; Cell Line, Tumor ; Cell Proliferation/genetics* ; Gene Expression Regulation, Neoplastic

OBJECTIVE: In this study, the combined effect of two stressors, namely, electromagnetic fields (EMFs) from mobile phones and fructose consumption, on hypothalamic and hepatic master metabolic regulators of the AMPK/SIRT1-UCP2/FOXO1 pathway were elucidated to delineate the underlying molecular mechanisms of insulin resistance. METHODS: Weaned Wistar rats (28 days old) were divided into 4 groups: Normal, Exposure Only (ExpO), Fructose Only (FruO), and Exposure and Fructose (EF). Each group was provided standard laboratory chow ad libitum for 8 weeks . Additionally, the control groups, namely, the Normal and FruO groups, had unrestricted access to drinking water and fructose solution (15%), respectively. Furthermore, the respective treatment groups, namely, the ExpO and EF groups, received EMF exposure (1,760 MHz, 2 h/day x 8 weeks). In early adulthood, mitochondrial function, insulin receptor signaling, and oxidative stress signals in hypothalamic and hepatic tissues were assessed using western blotting and biochemical analysis. RESULT: In the hypothalamic tissue of EF, SIRT1, FOXO 1, p-PI3K, p-AKT, Complex III, UCP2, MnSOD, and catalase expressions and OXPHOS and GSH activities were significantly decreased ( P < 0.05) compared to the Normal, ExpO, and FruO groups. In hepatic tissue of EF, the p-AMPKα, SIRT1, FOXO1, IRS1, p-PI3K, Complex I, II, III, IV, V, UCP2, and MnSOD expressions and the activity of OXPHOS, SOD, catalase, and GSH were significantly reduced compared to the Normal group ( P < 0.05). CONCLUSION The findings suggest that the combination of EMF exposure and fructose consumption during childhood and adolescence in Wistar rats disrupts the closely interlinked and multi-regulated crosstalk of insulin receptor signals, mitochondrial OXPHOS, and the antioxidant defense system in the hypothalamus and liver.
Humans ; Rats ; Animals ; Adult ; Rats, Wistar ; Fructose/metabolism* ; Catalase ; Receptor, Insulin/metabolism* ; AMP-Activated Protein Kinases/metabolism* ; Electromagnetic Fields/adverse effects* ; Sirtuin 1/metabolism* ; Cell Phone ; Phosphatidylinositol 3-Kinases/metabolism* ; Forkhead Box Protein O1/metabolism* ; Uncoupling Protein 2

D-allulose-3-epimerase (DPEase) is the key enzyme for isomerization of D-fructose to D-allulose. In order to improve its thermal stability, short amphiphilic peptides (SAP) were fused to the N-terminal of DPEase. SDS-PAGE analysis showed that the heterologously expressed DPEase folded correctly in Bacillus subtilis, and the protein size was 33 kDa. After incubation at 40 °C for 48 h, the residual enzyme activity of SAP1-DSDPEase was 58%. To make the recombinant B. subtilis strain reusable, cells were immobilized with a composite carrier of sodium alginate (SA) and titanium dioxide (TiO2). The results showed that 2% SA, 2% CaCl2, 0.03% glutaraldehyde solution and a ratio of TiO2 to SA of 1:4 were optimal for immobilization. Under these conditions, up to 82% of the activity of immobilized cells could be retained. Compared with free cells, the optimal reaction temperature of immobilized cells remained unchanged at 80 °C but the thermal stability improved. After 10 consecutive cycles, the mechanical strength remained unchanged, while 58% of the enzyme activity could be retained, with a conversion rate of 28.8% achieved. This study demonstrated a simple approach for using SAPs to improve the thermal stability of recombinant enzymes. Moreover, addition of TiO2 into SA during immobilization was demonstrated to increase the mechanical strength and reduce cell leakage.
Bacillus subtilis/metabolism* ; Carbohydrate Epimerases/genetics* ; Enzyme Stability ; Enzymes, Immobilized/metabolism* ; Fructose ; Hydrogen-Ion Concentration ; Racemases and Epimerases ; Temperature

It is of great significance to use biosynthesis to transform the inorganic substance formaldehyde into organic sugars. Most important in this process was to find a suitable catalyst combination to achieve the dimerization of formaldehyde. In a recent report, an engineered glycolaldehyde synthase was reported to catalyze this reaction. It could be combined with engineered D-fructose-6-phosphate aldolase, a "one-pot enzyme" method, to synthesize L-xylose using formaldehyde and the conversion rate could reach up to 64%. This process also provides a reference for the synthesis of other sugars. With the increasing consumption of non-renewable resources, it was of great significance to convert formaldehyde into sugar by biosynthesis.
Biocatalysis ; Formaldehyde ; chemistry ; Fructose-Bisphosphate Aldolase ; metabolism ; Xylose ; chemical synthesis

The aim of this paper was to investigate the molecular mechanism of Calculus Bovis Sativus( CBS) in alleviating lipid accumulation in vitro by serum pharmacology. The CBS-containing serum of mice was obtained by serum pharmacology method to evaluate its effect on the proliferation of LO2 hepatocytes. The lipid reducing effects of CBS-containing serum through Nrf2 was evaluated by fructose-induced LO2 hepatocyte steatosis model,nuclear factor erythroid 2 related factor 2( Nrf2) agonist oltipraz combined intervention,cell oil red O staining and intracellular triglyceride( TG) content. The effects of CBS-containing serum on lipid peroxidation and hepatocytes apoptosis were evaluated by reactive oxygen species( ROS) and apoptosis assay,respectively. Real-time quantitative polymerase chain reaction( PCR) was used to detect the relative expression of lipid synthesis-related genes and apoptosis-related genes.RESULTS:: showed that CBS drug-containing serum had no significant effect on LO2 hepatocyte proliferation. As compared with the model group,CBS-containing serum could effectively reduce the formation of lipid droplets in fructose-induced LO2 hepatocytes,significantly reduce intracellular TG and ROS levels,and significantly reduce hepatocyte apoptosis rate( P < 0. 05). As compared with the model group,carbohydrate responsive element binding protein( ChREBP),sterol regulatory element binding protein-1 c( SREBP-1 c),fatty acid synthase( FAS),acetyl-CoA carboxylase 1( ACC1),stearoyl-CoA desaturase 1( SCD1),Bax and caspase-3 mRNA levels were significantly reduced in CBS drug-containing serum treatment group( P<0. 05). All of the above effects could be reversed by oltipraz.In conclusion,CBS-containing serum can significantly inhibit the fructose-induced LO2 liver fat deposition,and the mechanism may be related to reducing intracellular ROS level through the Nrf2 pathway and improving intracellular peroxidation state to reduce apoptosis.
Animals ; Apoptosis ; Cattle ; Cells, Cultured ; Fatty Liver ; Fructose ; Gallstones ; chemistry ; Hepatocytes ; cytology ; metabolism ; Lipid Metabolism ; Lipid Peroxidation ; Liver ; Medicine, Chinese Traditional ; Mice ; Reactive Oxygen Species ; metabolism ; Serum ; chemistry ; Sterol Regulatory Element Binding Protein 1 ; metabolism ; Triglycerides

Human seminal plasma is rich in potential biological markers for male infertility and male reproductive system diseases, which have an application value in the diagnosis and treatment of male infertility. The methods for the detection of semen biochemical markers have been developed from the manual, semi-automatic to the present automatic means. The automatic detection of semen biochemical markers is known for its advantages of simple reagent composition and small amount of reagents for each test, simple setting of parameters, whole automatic procedure with few errors, short detection time contributive to batch detection and reduction of manpower cost, simple calibration and quality control procedure to ensure accurate and reliable results, output of results in the order of the samples in favor of clinical diagnosis and treatment, and open reagents applicable to various automatic biochemistry analyzers. At present, the automatic method is applied in the detection of such semen biochemical markers as seminal plasma total and neutral alpha-glucosidase, acid phosphatase, fructose, γ-glutamyl transpeptidase, zinc, citric acid, uric acid, superoxide dismutase and carnitine, sperm acrosin and lactate dehydrogenase C4, and semen free elastase, which can be used to evaluate the secretory functions of the epididymis, seminal vesicle and prostate, sperm acrosome and energy metabolism function, seminal plasma antioxidative function, and infection or silent infection in the male genital tract.
Acid Phosphatase ; analysis ; Biomarkers ; analysis ; Carnitine ; analysis ; Citric Acid ; analysis ; Epididymis ; metabolism ; Fructose ; analysis ; Humans ; Infertility, Male ; diagnosis ; Isoenzymes ; L-Lactate Dehydrogenase ; Male ; Prostate ; metabolism ; Semen ; chemistry ; Seminal Vesicles ; Spermatozoa ; chemistry ; alpha-Glucosidases ; analysis ; gamma-Glutamyltransferase ; analysis

BackgroundA high consumption of fructose leads to hepatic steatosis. About 20-30% of triglycerides are synthesized via de novo lipogenesis. Some studies showed that endoplasmic reticulum stress (ERS) is involved in this process, while others showed that a lipotoxic environment directly influences ER homeostasis. Here, our aim was to investigate the causal relationship between ERS and fatty acid synthesis and the effect of X-box binding protein-1 (XBP-1), one marker of ERS, on hepatic lipid accumulation stimulated by high fructose.

MethodsHepG2 cells were incubated with different concentrations of fructose. Upstream regulators of de novo lipogenesis (i.e., carbohydrate response element-binding protein [ChREBP] and sterol regulatory element-binding protein 1c [SREBP-1c]) were measured by polymerase chain reaction and key lipogenic enzymes (acetyl-CoA carboxylase [ACC], fatty acid synthase [FAS], and stearoyl-CoA desaturase-1 [SCD-1]) by Western blotting. The same lipogenesis-associated factors were then evaluated after exposure of HepG2 cells to high fructose followed by the ERS inhibitor tauroursodeoxycholic acid (TUDCA) or the ERS inducer thapsigargin. Finally, the same lipogenesis-associated factors were evaluated in HepG2 cells after XBP-1 upregulation or downregulation through cell transfection.

ResultsExposure to high fructose increased triglyceride levels in a dose- and time-dependent manner and significantly increased mRNA levels of SREBP-1c and ChREBP and protein levels of FAS, ACC, and SCD-1, concomitant with XBP-1 conversion to an active spliced form. Lipogenesis-associated factors induced by high fructose were inhibited by TUDCA and induced by thapsigargin. Triglyceride level in XBP-1-deficient group decreased significantly compared with high-fructose group (4.41 ± 0.54 μmol/g vs. 6.52 ± 0.38 μmol/g, P < 0.001), as mRNA expressions of SREBP-1c (2.92 ± 0.46 vs. 5.08 ± 0.41, P < 0.01) and protein levels of FAS (0.53 ± 0.06 vs. 0.85 ± 0.05, P = 0.01), SCD-1 (0.65 ± 0.06 vs. 0.90 ± 0.04, P = 0.04), and ACC (0.38 ± 0.03 vs. 0.95 ± 0.06, P < 0.01) decreased. Conversely, levels of triglyceride (4.22 ± 0.54 μmol/g vs. 2.41 ± 0.35 μmol/g, P < 0.001), mRNA expression of SREBP-1c (2.70 ± 0.33 vs. 1.00 ± 0.00, P < 0.01), and protein expression of SCD-1 (0.93 ± 0.06 vs. 0.26 ± 0.05, P < 0.01), ACC (0.98 ± 0.09 vs. 0.43 ± 0.03, P < 0.01), and FAS (0.90 ± 0.33 vs. 0.71 ± 0.02, P = 0.04) in XBP-1s-upregulated group increased compared with the untransfected group.

ConclusionsERS is associated with de novo lipogenesis, and XBP-1 partially mediates high-fructose-induced lipid accumulation in HepG2 cells through augmentation of de novo lipogenesis.

Endoplasmic Reticulum Stress ; physiology ; Fatty Liver ; Fructose ; metabolism ; Hep G2 Cells ; Humans ; Lipogenesis ; physiology ; Liver ; Sterol Regulatory Element Binding Protein 1 ; X-Box Binding Protein 1 ; physiology

Fructose intake has increased dramatically over the past century and the upward trend has continued until recently. Increasing evidence suggests that the excessive intake of fructose induces salt-sensitive hypertension. While the underlying mechanism is complex, the kidney likely plays a major role. This review will highlight recent advances in the renal mechanisms of fructose-induced salt-sensitive hypertension, including (pro)renin receptor-dependent activation of intrarenal renin-angiotensin system, increased nephron Na transport activity via sodium/hydrogen exchanger 3 and Na/K/2Cl cotransporter, increased renal uric acid production, decreased renal nitric oxide production, and increased renal reactive oxygen species production, and suggest actions based on these mechanisms that have therapeutic implications.
Blood Pressure ; Fructose ; adverse effects ; Humans ; Hypertension ; chemically induced ; physiopathology ; Kidney ; physiopathology ; Nitric Oxide ; metabolism ; Reactive Oxygen Species ; metabolism ; Renin-Angiotensin System ; Sodium Chloride, Dietary ; adverse effects ; Sodium-Hydrogen Exchanger 3 ; metabolism ; Uric Acid ; metabolism

We have previously reported that NS-398, a cyclooxygenase-2 (COX-2)–selective inhibitor, inhibited replicative cellular senescence in human dermal fibroblasts and skin aging in hairless mice. In contrast, celecoxib, another COX-2–selective inhibitor, and aspirin, a non-selective COX inhibitor, accelerated the senescence and aging. To figure out causal factors for the senescence-modulating effect of the inhibitors, we here performed cDNA microarray experiment and subsequent Gene Set Enrichment Analysis. The data showed that several senescence-related gene sets were regulated by the inhibitor treatment. NS-398 up-regulated gene sets involved in the tumor necrosis factor β receptor pathway and the fructose and mannose metabolism, whereas it down-regulated a gene set involved in protein secretion. Celecoxib up-regulated gene sets involved in G2M checkpoint and E2F targets. Aspirin up-regulated the gene set involved in protein secretion, and down-regulated gene sets involved in RNA transcription. These results suggest that COX inhibitors modulate cellular senescence by different mechanisms and will provide useful information to understand senescence-modulating mechanisms of COX inhibitors.
Aging ; Animals ; Aspirin ; Celecoxib ; Cell Aging ; Cyclooxygenase 2 ; Fibroblasts* ; Fructose ; Gene Expression* ; Genes, vif ; Humans* ; Mannose ; Metabolism ; Mice ; Mice, Hairless ; Oligonucleotide Array Sequence Analysis ; RNA ; Skin Aging ; Tumor Necrosis Factor-alpha

Excessive fructose intake is related to a high prevalence of metabolic syndrome, while little attention has been paid to the impact of maternal high-fructose (HF) intake on the development of metabolic syndrome and organ-specific transcriptome alterations in the offspring. We utilized RNA next-generation sequencing (NGS) technology to analyze the transcriptome expression in four organs (kidney, brain, heart, and urinary bladder) from 1-day, 3-week, and 3-month-old male offspring exposed to maternal HF diet. Maternal HF induced various phenotypes of metabolic syndrome in adult male offspring. We observed that maternal HF exposure induces long-term alterations of gene expression in the brain, heart, kidney, and urinary bladder in adult offspring. Different organs do not respond similarly to maternal HF intake. We found that changes in expression of Errfi1 and Ctgf were shared by four organs at 1 day of age. Also, a number of genes regulating fructose metabolism, glycolysis/gluconeogenesis, fatty acid metabolism, and insulin signalling appear to be regulated by maternal HF intake in different organs at 1 day of age. Our NGS results are of significance to the development of maternal interventions in the prevention of maternal HF-induced organ-specific programming, in order to reduce the global burden of metabolic syndrome.
Animals ; Female ; Fructose ; Kidney ; Lipid Metabolism ; Male ; Metabolic Syndrome ; Pregnancy ; Rats ; Rats, Sprague-Dawley ; Transcriptome