Mechanism of Dihuang Yinzi in Improving Astrocyte Injury and Glycolysis in AD Mice via PI3K/Akt Pathway / 中国实验方剂学杂志

ObjectiveTo explore the mechanism of Dihuang Yinzi in improving astrocyte injury and glycolysis in Alzheimer's disease （AD） mice via regulating the phosphatidylinositol 3-kinase （PI3K）/protein kinase B （Akt） signaling pathway， thereby improving the cognitive function of AD mice. MethodForty male APP/PS1 transgenic mice aged four months were randomly divided into a model group and a model + Dihuang Yinzi （0.25 g·kg-1） group， with 20 mice in each group. Forty C57BL/6J mice with the same background and same age were randomly divided into a control group and a control + Dihuang Yinzi （0.25 g·kg-1） group， with 20 mice in each group. The mice in the control + Dihuang Yinzi group and the model + Dihuang Yinzi group were administered with Dihuang Yinzi by gavage， and those in the control group and the model group received an equal volume of sterilized normal saline， once a day for 150 days. Morris water maze test was performed to test the ability of navigation and space exploration of mice. The protein expression of p-PI3K， PI3K， p-Akt， Akt， phosphofructokinase-1 （PFK-1）， and aldehyde dehydrogenase 3 family member B2 （ALDH3B2） in mouse brain tissues was measured by Western blot. An immunofluorescence assay was performed to detect astrocyte morphology and the expression level of ALDH3B2. ResultAs compared with the control group， the model group showed prolonged escape latency during the 2nd to 5th days of the location-based navigation （P<0.05， P<0.01）， reduced number of times crossing the target area of the platform， shortened residence time in the target quadrant （P<0.05， P<0.01）， prolonged residence time in the opposite quadrant （P<0.05）， increased surface area of the cell body and total length of cell protrusions of astrocytes （P<0.05， P<0.01）， and down-regulated protein expression of p-PI3K， p-Akt， ALDH3B2， and PFK-1 （P<0.01）， while the above experimental indexes were not significantly different in the control + Dihuang Yinzi group. Compared with the model group， the model + Dihuang Yinzi group showed shortened escape latency of APP/PS1 mice during the 2nd to 5th days of the location-based navigation （P<0.05， P<0.01）， increased number of times crossing the platform， prolonged target quadrant residence time （P<0.05， P<0.01）， shortened residence time in the opposite quadrant （P<0.05）， reduced surface area of the cell body and total length of cell protrusions of astrocytes （P<0.05）， and up-regulated protein expression of p-PI3K， p-Akt， ALDH3B2， and PFK-1 （P<0.01）. ConclusionDihuang Yinzi can improve the learning and memory ability of AD mice by activating the PI3K/Akt signaling pathway and up-regulating the protein expression of PFK-1 and ALDH3B2 to protect against astrocyte injury in brain tissues and improve glycolysis.

Oligomycin A promotes radioresistance in HT29 colorectal cancer cells and its mechanisms / 中南大学学报(医学版)

OBJECTIVES@#Radiotherapy is one of the main therapies for colorectal cancer, but radioresistance often leads to radiotherapy failure. To improve the radioresistance, we explore the effect of oligomycin A, the H@*METHODS@#The effects of different concentrations of oligomycin A on the survival rate and glycolysis of HT29 colorectal cancer cells at different time points were investigated via MTT and glycolysis assay. siRNA-PFK1 was synthesized in vitro and transfected into HT29 cells. The effects of oligomycin A on radiosensitivity of HT29 colorectal cancer cells were measured via MTT and colony formation assay. Western blotting was used to detect the effect of oligomycin A on the expression of glycolytic enzyme PFK1. We compared difference between the effects of siRNA-PFK1 group and oligomycin A combined with siRNA-PFK1 group on cell survival and glycolysis. After 4 Gy X-ray irradiation, the effects of cell survival and glycolysis between the siRNA-PFK1 group and the oligomycin A combined with siRNA-PFK1 group were compared.@*RESULTS@#Compared with the 0 μmol/L oligomycin A group, the cell survival rate of HT29 cells treated with 4 μmol/L oligomycin A was significantly increased (@*CONCLUSIONS@#Oligomycin A can promote the radioresistance of HT29 colorectal cancer cells, which may be related to up-regulation of the PFK1 expression and increase of cell glycolysis.

Effect of Qingzao Jiufei Tang on Rate-limiting Enzymes HK2, PFK2 and PKM2 in Glycolytic Pathway in Lewis Lung Cancer-bearing Mice Cells / 中国实验方剂学杂志

Objective::To study the effect of Qingzao Jiufei Tang on the expression of key limiting enzymes hexokinase 2(HK2), phosphofructokinase 2(PFK2) and pyruvate kinase M2 (PKM2), and the glucose content in Lewis mice colon cancer cells. Method::A total of 50 male C57BL/6J mice were randomly divided into model group, chemotherapy group, and high, middle and low-dose Qingzao Jiufei Tang groups, with 10 mice in each group. The lung cancer cell model was established by injecting Lewis lung cancer cells into the right axilla. The high, middle and low dose groups were administered at the doses of 11, 5.5, 2.75 g·kg-1·d-1 for 2 weeks before modeling. The drug was administered through intraperitoneal injection at a dose of 50 mg·kg-1·(2 d)-1 in the chemotherapy group. The model group was intragastrically administered with an equal volume of normal saline. After the inoculation, the drug was administered for two weeks. Two weeks later, all of the mice were put to death, and tumor tissues were collected. The mRNA expression of HK2 was detected by Real-time PCR. the protein expression of PFK2 was detected by Western blot, the PKM2 activity was detected by enzyme-linked immunosorbent assay (ELISA). Result::Compared with the model group, mRNA expressions and activity of PKM2 in lung cancer cells of treatment groups were significantly declined, and glucose content increased significantly, with significant differences from those of model group (P<0.01). The PFK2 protein expressions in lung cancer cells of treatment groups (high, medium and low-dose groups) were significantly decreased (P<0.05, P<0.01). Conclusion::Qingzao Jiufei Tang could inhibit Lewis proliferation, and decrease the glucose intake in lung cancer cells. The effect targets may be the key rate-limiting enzymes HK2, PFK2, PKM2.

Evaluation of 6-Gingerol and its modified analogues as therapeutic candidates against Schistosoma mansoni phosphofructokinase

The African most prevalent tropical disease after malaria is schistosomiasis and this disease in the developing countries is a massive socio-economic and public health burden. The disease also caused over 200,000 deaths. The development and design of new and novel antischistosomal drugs is now very important, as there are no vaccines currently and there is only one drug at the moment for the treatment of schistosomiasis. In this article, 6-gingerol was docked against the Schistosoma mansoni phosphofructokinase and the docking result was compared to those obtained from the docking of its modified analogues against the same enzyme. The chemical structure of 6-gingerol was obtained from the PubChem database while the modified analogues were designed using the ChemAxon software. The molecular docking procedure was carried out with the aid of the AutoDock Vina software while polar interactions which were eventually used in predicting the amino acid residues at the Schistosoma mansoni phosphofructokinase active site were visualized using the Pymol software. The Schistosoma mansoni phosphofructokinase 3D crystallized structure was modeled using the Swiss Model server. The molecular docking result showed that the modifications made on 6-gingerol had a positive effect on the binding energy of the compound to the enzyme active site as an appreciable increase was observed. 6-Gingerol and its modified analogues also violated none of the Lipinski's rule with suggests that the experimental compounds are drug-like. The C2H5 analogue of 6 gingerol was selected as the ideal therapeutic agent based on the pharmacokinetics study and the exhibited binding energy(AU)

La enfermedad tropical con más prevalencia en África después de la malaria es la esquistosomiasis; en los países en vías de desarrollo constituye una carga socio-económica y de salud pública enorme. La enfermedad ha ocasionado más de 200.000 muertes anuales. El desarrollo y diseño de nuevas y novedosas drogas antiesquistosomales es muy importante, ya que actualmente no existe vacuna disponible y solo hay una sola droga licenciada para su tratamiento. En esta investigación, el compuesto 6-gingerol se acopló a la enzima fosfofructoquinasa de Schistosoma mansoni y se comparó con los resultados obtenidos a partir de las interacciones de sus análogos modificados a la misma enzima. La estructura química del 6-gingerol se obtuvo de la base de datos PubChem, mientras que los análogos modificados se diseñaron utilizando el software ChemAxon. El procedimiento de acoplamiento molecular se llevó a cabo con la ayuda del software AutoDockVina, mientras las interacciones polares eventualmente utilizadas para predecir los residuos de aminoácidos en el sitio activo de la enzima fosfofructoquinasa de Schistosoma mansoni se visualizaron empleando el software Pymol. La estructura cristalizada tridimensional de la enzima fosfofructoquinasa de Schistosoma mansoni se modeló utilizando el programa Swiss Model. Se demostró que las modificaciones realizadas en el 6-gingerol tuvieron un efecto positivo en la energía de unión del compuesto al sitio activo de la enzima, tras observarse un aumento apreciable de dicha energía. El compuesto 6-Gingerol y sus análogos modificados tampoco violaron ninguna de las reglas de Lipinski, lo que sugiere que estos compuestos experimentales tienen propiedades similares a los medicamentos. El análogo C2H5 de 6-gingerol se seleccionó como el agente terapéutico ideal, basados en el estudio de farmacocinética y la energía de enlace demostrada(AU)

Expression of PFKFB3 in brain glioma tissues and its effect on malignant biological behaviors of H4 cells / 中国肿瘤生物治疗杂志

@#[Abstract] Objective: Toevaluatetheexpressionof6-phosphofructo-2-kinase/fructose-2, 6-biphosphatase 3(PFKFB3) in malignant glioma tissues and the effects of inhibitor of PFKFB3(PFK15) on the proliferation, migration, invasion, clone formation and tumorigenesis of H4 cells. Methods: Malignant brain glioma tissues and corresponding paratumor tissues from 31 patients, who were hospitalized in Department of Neurosurgery,Ankang Hospital of Traditional Chinese Medicine during February 1, 2015 to January 31, 2016 for operative treatment, were collected for this study. Immunohistochemistry and western blotting assays were applied to detect the expression of PFKFB3 in collected tissues. PFKFB3 in H4 cells were blocked by PFK15 (1.25, 2.5, 5.0 μmol/L). The effect of PFK15 on proliferation, migration, clone formation and tumorigenesis of H4 cells were determined by MTT assay, EdU incorporation assay, wound healing assay, Transwell assay, colone formation assay and in vivo xenograft bearing nude mice model respectively. Results: Positive expression rate of PFKFB3 was significantly higher in malignant glioma tissues compared with normal adjacent tissues[(80.60±8.98)% vs (41.57±10.16)%, P<0.05]. The results of MTT assay and EdU incorporation assay indicated that PEK15 significantly inhibited the proliferation of H4 cells in a concentration dependent manner. The migration, invasion and clone formation activity of H4 cells were significantly reduced by treatment with PFK15 (all P<0.05). In tumor bearing nude mice, the tumor volume of mice treated with PFK15 was significantly smaller than that of mice from control group ([254.15±154.25] vs [801.52±224.25] mm3, P<0.05). Conclusion: PFKFB3 was highly expressed in malignant glioma tissues. Blocking of PFKFB3 by PFK15 significantly reduced the malignant biological behaviors and tumorigenesis of H4 cells in vitro and in vivo, which may serve as a promising target for the treatment of malignant gliomas.

Metabolic engineering of Saccharomyces cerevisiae for production of glucaric acid / 生物工程学报

Glucaric acid, a high value-added organic acid, is widely used in food, pharmaceutical and chemical industries. For microbial production of glucaric acid in Saccharomyces cerevisiae, we constructed a synthetic glucaric acid biosynthetic pathway by coexpressing the genes encoding myo-inositol oxygenase from mice and uronate dehydrogenase from Pseudomonas putida. Moreover, myo-inositol-1-phosphate synthase was identified as a rate-limiting enzyme in glucaric acid pathway and was upregulated, resulting in the production of glucaric acid of (107.51±10.87) mg/L, a 2.8-fold increase compared to the parent strain. Then, by repressing the activity of phosphofructokinase, the concentration of glucaric acid further increased to (230.22±10.75) mg/L. The strategy could be further used to construct cell factories for glucaric acid production.

Research progress in anti-tumor angiogenesis targeting rate-limiting enzyme PFKFB3 in glycolytic pathway of endothelial cells / 肿瘤

Angiogenesis is essential for the occurrence, growth and metastasis of tumors. The differentiation and neovascularization of vascular endothelial cells depend on the energy supply by metabolism and its regulation, especially the glycolysis pathway is very important for vascular sprouting which is a starting point in the process of tumor angiogenesis. It has been found that phosphofructokinase-2/fructose-2,6-bisphosphatase 3 (PFKFB3), a key rate-limiting enzyme of glycolysis pathway, has strong kinase activity. If the activity of PFKFB3 is inhibited, the rate of glycolysis can be reduced, thereby the vascular sprouting in tumor angiogenesis can be blocked. It has been demonstrated that PFKFB3 inhibitor 3-(3-pyridinyl)-1-(4-pyridinyl)-2-propen-1-one (3PO) can prominently reduce glycolysis and inhibit the pathologic angiogenesis. Therefore, in recent years, it becomes a new research hotspot in the field of cancer therapy to inhibit or destroy the metabolism of tumor vascular endothelial cells for the purpose of curing cancer. This review summarizes the effect of PFKFB3 in glycolysis of endothelial cells on tumor angiogenesis, and the research progress in PFKFB3 as a target for cancer treatment.

Poly(ADP-ribose) polymerase regulates glycolytic activity in kidney proximal tubule epithelial cells / 대한해부학회지

After renal injury, selective damage occurs in the proximal tubules as a result of inhibition of glycolysis. The molecular mechanism of damage is not known. Poly(ADP-ribose) polymerase (PARP) activation plays a critical role of proximal tubular cell death in several renal disorders. Here, we studied the role of PARP on glycolytic flux in pig kidney proximal tubule epithelial LLC-PK1 cells using XFp extracellular flux analysis. Poly(ADP-ribosyl)ation by PARP activation was increased approximately 2-fold by incubation of the cells in 10 mM glucose for 30 minutes, but treatment with the PARP inhibitor 3-aminobenzamide (3-AB) does-dependently prevented the glucose-induced PARP activation (approximately 14.4% decrease in 0.1 mM 3-AB-treated group and 36.7% decrease in 1 mM 3-AB-treated group). Treatment with 1 mM 3-AB significantly enhanced the glucose-mediated increase in the extracellular acidification rate (61.1±4.3 mpH/min vs. 126.8±6.2 mpH/min or approximately 2-fold) compared with treatment with vehicle, indicating that PARP inhibition increases only glycolytic activity during glycolytic flux including basal glycolysis, glycolytic activity, and glycolytic capacity in kidney proximal tubule epithelial cells. Glucose increased the activities of glycolytic enzymes including hexokinase, phosphoglucose isomerase, phosphofructokinase-1, glyceraldehyde-3-phosphate dehydrogenase, enolase, and pyruvate kinase in LLC-PK1 cells. Furthermore, PARP inhibition selectively augmented the activities of hexokinase (approximately 1.4-fold over vehicle group), phosphofructokinase-1 (approximately 1.6-fold over vehicle group), and glyceraldehyde-3-phosphate dehydrogenase (approximately 2.2-fold over vehicle group). In conclusion, these data suggest that PARP activation may regulate glycolytic activity via poly(ADP-ribosyl)ation of hexokinase, phosphofructokinase-1, and glyceraldehyde-3-phosphate dehydrogenase in kidney proximal tubule epithelial cells.

Molecular and biochemical characterisation of Trypanosoma cruzi phosphofructokinase

The characterisation of the gene encoding Trypanosoma cruzi CL Brener phosphofructokinase (PFK) and the biochemical properties of the expressed enzyme are reported here. In contradiction with previous reports, the PFK genes of CL Brener and YBM strain T. cruzi were found to be similar to their Leishmania mexicana and Trypanosoma brucei homologs in terms of both kinetic properties and size, with open reading frames encoding polypeptides with a deduced molecular mass of 53,483. The predicted amino acid sequence contains the C-terminal glycosome-targeting tripeptide SKL; this localisation was confirmed by immunofluorescence assays. In sequence comparisons with the genes of other eukaryotes, it was found that, despite being an adenosine triphosphate-dependent enzyme, T. cruzi PFK shows significant sequence similarity with inorganic pyrophosphate-dependent PFKs.

Effects of repeated hypoxic exposures on glycolysis, mitochondrial oxidative phosphorylation and energy charge in mouse brain / 基础医学与临床

Objective To study the effects of repeated hypoxic exposures (HEs) on glycolysis, mitochondrial oxi-dative phosphorylation and energy charge in mouse brain. Methods Adult BALB/c mice were repeatedly exposed to hypoxia for 5 times and the standard tolerant time and body temperature were recorded. The activities of PFK, PK and mitochondrial complex Ⅰ in the brain were assayed. Phosphoadenosines and energy charge were measured. Results Repeated HEs prolonged the hypoxic tolerance and reduced the body temperature. The activities of PFK and PK experienced regular changes, with an increase in 1st and 3rd HEs and a decline to control levels in 5th HE. The complex Ⅰ activity continued to decrease during HEs. The energy charge was stable. Conclusion HEs lead to a regular change of glycolysis, a continued inhibition of mitochondrial oxidative phosphorylation, and a main-tained energy charge in the brains of mouse.

Perioperative changes of erythrocytes hexokinase, phosphofructokinase and glucose-6-phasphate dehydrogenase activities in patients undergoing upper abdominal surgery / 中华麻醉学杂志

Objective To investigate the role of pentose phosphate pathway (PPP) after upper abdominal operationMethods Twenty-six patients undergoing upper abdominal surgery, were divided randomly into three groups: epidural block(EB,n=10), intravenous propofol anesthesia(PRO, n=10) and intravenous procaine balanced anesthesia(IPBA,n=6) The venous blood samples were collected to measure of erythrocytes hexokinase (HK), phosphofructokinase (PFK) and glucose-6-phasphate dehydrogenase (G-6PD), and activities, and plasma glucose before anesthesia induction, 60 min after incision,60 min after surgery, on the 1st and 2nd postoperative daysResults Compared with the values before anesthesia, the activities of erythrocyte HK and PFK decreased significantly on the 1st postoperative day in three groups (P

Perioperative changes of erythrocyte phosphofructokinase activity and content of ATP and Mg~(2+) in patients undergoing open heart surgery / 中华麻醉学杂志

To observe the perioperative changes of erythrocyte (RBC) phosphofructokinase (PFK) activity and content of ATP and Mg~(2+) in patients undergoing open heart surgery. Method: Fifteen patients undergoing open heart surgery were admitted to this study. Arterial blood samples were collected for the measurements of PFK aczivity, contents of ATP and Mg~(2+) in RBC at 9 points: before anesthesia induction, spiliting sternum, the beginning of CPB.5 minutes after aorta occlusion, at the end of CPB, at the end of operation.on the lst,2nd and 3rd postoperative day. Result: Erythrocyte PFK activity had no marked change during anesthesia, but was decreased significantly on the 1st postoperative day compared with beseline (P

Influence of reduced food intake on enzyme activities in developing soleus and extensor digitorum longus muscles of rats / 体力科学

To investigate whether or not retardation of body weight increase by reduced food intake could change enzyme activities in the soleus and extensor digitorum longus (EDL) muscles during growth, rats were divided into three groups. Group 1 included rats aged 5, 7, 9, 11 weeks fed ad libitum. Group 2 included rats aged 5, 7, 9, 11 weeks fed a restricted diet. These animals weighed as much as the 5-week-old rats in group 1. Group 3 included four subgroups of 11-week-old rats. Their body weights were adjusted to the weights of rats 5, 7, 9 and 11 weeks old in group 1 by restriction of food intake. Succinate dehydrogenase (SDH) activity in the soleus muscle increased significantly with growth. Though a similar change was not observed with age in group 2, SDH activity in the soleus muscle in group 3 was enhanced with increasing body weight. Phosphofructokinase (PFK) activity in the soleus muscle decreased with growth in groups 1 and 2, but this change was not statistically significant. In group 3, PFK activity in the soleus muscle did not fluctuate with increasing body weight. In groups 1 and 2 there was a significant correlation between PFK activity and percentage area of type I fibers in the soleus muscle (r=-0.63, p<0.01, r=-0.55, p<0.01, respectively), but no significant relationship between them was evident in group 3. PFK activity in the EDL muscle increased significantly with growth in groups 1 and 2, but did not change with increasing body weight in group 3. It is suggested that the increase of SDH activity in the soleus muscle between the ages of 5 and 11 weeks is influenced primarily by changes in body weight, but that the changes of PFK in the soleus and EDL muscles are not modified by this factor.

Developmental changes of the glycolytic enzymes in the human fetal heart.

The ontogeny of hexokinase, phosphofructokinase, phosphoglucoisornerase, aldolase, pyruvate kinase and lactate dehydrogenase activities which are associated with glycolysis, an important energy yielding process, has been studied in human fetal heart for periods ranging from 13 weeks to above 33 weeks of gestation. Hexokinase, phosphoglucoisomerase and pyruvate kinase activities show similar developmental profiles exhibiting maximum activity at 25-28 weeks ofgestation. Phosphofructokinase activity, on the other hand, shows a minimum at this period and exhibits a peak value at early stages (13-16 weeks of gestation). Though considerable activity for aldolase is observed at an early period, it declines thereafter, but again increases in the later period. The probable role and correlations of these glycolytic enzymes with energy demand and general functional development in human fetal heart in ontogeny are evaluated.

Purification of rabbit liver phosphofructokinase and its properties under simulating in vivo conditions.

Phosphofructokinase (EC 2.7.1.11) from rabbit liver was purified to homogeneity. Preincubation of enzyme results in nonlinearity of enzyme activity with enzyme concentration. Therefore K0·5 of enzyme for fructose 6 phosphate in the absence or presence of fructose 2,6 bisphosphate or polyethylene glycol or in the presence of both was determined at physiological concentrations of its various effectors by taking the initial rate obtained by adding the enzyme last. They decrease the K0·5 value from 4·1 mM to about 0·2mM. The K0·5 of enzyme for fructose 2,6 bisphosphate was also determined under the above conditions. It is about 4·3 μΜ. Transient kinetics of phosphofructokinase at varying concentrations of enzyme in the presence of fructose 2,6 bisphosphate or polyethylene glycol or in the presence of both were studied. It was found that although they decrease t1/ 2 i.e. the time to reach half the maximal steady rate by about 5–8 fold, it was about constant at varying concentrations of the enzyme. These results indicate that fructose 2,6 bisphosphate and polyethylene glycol decrease K0·5 of the enzyme for fructose 6 phosphate not by associating the enzyme to higher aggregates, but by a different mechanism.