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)

Prosapogenin A inhibits cell growth of MCF7 via downregulating STAT3 and glycometabolism-related gene / 药学学报

This study is to investigate the inhibitory effect and mechanism of prosapogenin A (PSA) on MCF7. MTT assay was performed to determine the inhibitory effect of PSA on MCF7 cells. PI/Hoechst 33342 double staining was used to detect cell apoptosis. RT-PCR was used to test the mRNA levels of STAT3, GLUT1, HK and PFKL. Western blotting was performed to determine the expression of STAT3 and pSTAT3 protein in MCF7 cells. The results showed that PSA could dose-dependently inhibit cell growth of MCF7 followed by IC50 of 9.65 micrmol x L(-1) and promote cell apoptosis of MCF7. Reduced mRNA levels of STAT3, HK and PFKL were observed in MCF7 cells treated with 5 micromol x L(-1) of PSA. PSA also decreased the level of pSTAT3 protein. STAT3 siRNA caused decrease of mRNA of GLUT1, HK and PFKL which indicated STAT3 could regulate the expressions of GLUT1, HK and PFKL. The results suggested that PSA could inhibit cell growth and promote cell apoptosis of MCF7 via inhibition of STAT3 and glycometabolism-related gene.

Increasing the rate of drying reduces metabolic imbalance, lipid peroxidation and critical water content in radicles of garden pea (Pisum sativum L.)

Orthodox seeds become desiccation-sensitive as they undergo germination. As a result, germinating seeds serve as a model to study desiccation sensitivity in plant tissues. The effects of the rate of drying on the viability, respiratory metabolism and free radical processes were thus studied during dehydration and wet storage of radicles of Pisum sativum. For both drying regimes desiccation could be described by exponential and inverse modified functions. Viability, as assessed by germination capacity and tetrazolium staining, remained at 100% during rapid (< 24 h) desiccation. However, it declined sharply at c. 0.26 g g¹ dm following slow (c. 5 days) drying. Increasing the rate of dehydration thus lowered the critical water content for survival. Rapid desiccation was also associated with higher activities and levels of malate dehydrogenase and the oxidized form of nicotinamide adenine dinucleotide. It was also accompanied by lower hydroperoxide levels and membrane damage. In addition, the activitiy of glutathione reductase was greater during rapid drying. Ageing may have contributed to increased damage during slow dehydration, since viability declined even in wet storage after two weeks. The results presented are consistent with rapid desiccation reducing the accumulation of damage resulting from desiccation-induced aqueous-based deleterious reactions. In addition, they show that radicles are a useful model to study desiccation sensitivity in plant tissues.

Effects of estrogen on the expression of phosphofructokinase muscle-specific isoform in genioglossus of chronic intermittent hypoxia rats / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the effects of estrogen on the expression of phosphofructokinase muscle-specific isoform (PFK-M) in genioglossus of chronic intermittent hypoxia (CIH) rats.</p><p><b>METHODS</b>Fifty male SD rats were randomly divided into five groups: the normal control group (NC), the chronic intermittent hypoxia group (CIH), and three doses of estrogen plus hypoxia groups (LE, ME, HE). Rats in the latter four groups were used to build CIH models (8 h/d, 5 weeks). In the mean time, rats in the latter three groups were injected with three dose levels of estrogen (0.1, 0.2, 0.3 mg/kg), and rats in NC and CIH groups were injected with sterile olive oil as control. At the end of the treatment, the genioglossus was isolated and quickly removed. The mRNA levels of PFK-M were determined by real-time RT-PCR and the protein content of PFK-M was detected by Western blotting analysis.</p><p><b>RESULTS</b>PFK-M mRNA and protein in CIH group (2.144 ± 0.260, 0.875 ± 0.025) were both higher than those (1.000 ± 0.259, 0.413 ± 0.013) in NC group (P < 0.05). The expression of PFK-M mRNA in LE, ME and HE groups were 1.424 ± 0.193, 1.395 ± 0.251 and 1.310 ± 0.094, respectively. The expression of protein in LE, ME and HE groups were 0.638 ± 0.015, 0.576 ± 0.017 and 0.505 ± 0.021, respectively. Compared with CIH group, the expression of PFK-M mRNA and protein in LE, ME and HE groups were all inhibited significantly (P < 0.05). Among the three treatment groups, decreased protein content of PFK-M was observed only in HE group when compared with LE group (P < 0.05), but no significant difference was detected in the expression of PFK-M mRNA.</p><p><b>CONCLUSIONS</b>CIH exposure could increase the expression of PFK-M mRNA and protein in rat genioglossus, while estrogen administration could dose dependently inhibit the overexpression.</p>

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.

Glycolysis in Plasmodium falciparum results in modulation of host enzyme activities.

BACKGROUND & OBJECTIVES: Plasmodium falciparum, the causative agent of the most serious form of malaria, infects about 5-10% of the world human population per year. It is well established that the erythrocytic stages of the malaria parasite rely mainly on glycolysis for their energy supply. In the present study, the glucose utilisation of erythrocyte population with parasitaemia levels similar to that of malaria patients was measured. The results allowed us to assess the effect of the parasites on the glucose utilisation of the vast majority of uninfected erythrocytes. METHODS: Using [2-13C]glucose and nuclear magnetic resonance (NMR) technique, the glucose utilisation in normal red blood cell (RBC) and P. falciparum infected red blood cell (IRBC) populations was measured. The IRBC population consisted of > 96% RBC and < 4% of parasite infected red blood cells (PRBC). The glycolytic enzymes were assayed to assess the effect of infected red cells on the enzymatic activities of uninfected ones. RESULTS: The rate of glucose utilisation by IRBC was considerably higher than that of RBC. Upon addition of 25% v/v conditioned culture medium (CM) of IRBC, RBCs exhibited a significant decrease in glucose utilisation. The CM could directly inhibit the activities of RBC glycolytic enzymes-phosphofructokinase (PFK) and pyruvate kinase (PK), without interfering with the activity of the pentose phosphate pathway enzyme-glucose-6-phosphate dehydrogenase (G-6-PD). INTERPRETATION & CONCLUSION: The present study showed that the clinical level of P. falciparum infected RBCs (< 4% parasitaemia) significantly enhance the glycolytic flux as well as down-regulate the glucose utilisation rate in the majority of uninfected RBC population. The mechanism of inhibition seems to be direct inhibition of the regulatory glycolytic enzymes-PFK and PK.

Conservation of glycolytic oscillations in Saccharomyces cerevisiae and human pancreatic b-cells: a study of metabolic robustness

The present study compares two computer models of the first part of glucose catabolism in different organisms in search of evolutionarily conserved characteristics of the glycolysis cycle and proposes the main parameters that define the stable steady-state or oscillatory behavior of the glycolytic system. It is suggested that in both human pancreatic b-cells and Saccharomyces cerevisiae there are oscillations that, despite differences in wave form and period of oscillation, share the same robustness strategy: the oscillation is not controlled by only one but by at least two parameters that will have more or less control over the pathway flux depending on the initial state of the system as well as on extra-cellular conditions. This observation leads to two important interpretations: the first is that in both S. cerevisiae and human b-cells, despite differences in enzyme kinetics and mechanism of feedback control, evolution seems to have kept an oscillatory behavior coupled to the glucose concentration outside the cytoplasm, and the second is that the development of drugs to regulate metabolic dysfunctions in more complex systems may require further study, not only determining which enzyme is controlling the flux of the system but also under which conditions and how its control is maintained by the enzyme or transferred to other enzymes in the pathway as the drug starts acting.

Rapid prenatal detection of Down syndrome by homologous gene quantitative PCR / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To evaluate the use of homologous gene quantitative PCR (HGQ-PCR) as a method for non-invasive diagnosis of Down syndrome and for prevention of the birth of Down syndrome children.</p><p><b>METHODS</b>HGQ-PCR, which can directly detect the additional copy of chromosome 21 by comparing simultaneously amplified two highly homologous genes, i.e. the human liver-type phosphofructokinase located on chromosome 21 critical region of Down syndrome (PFKL-CH21) and the human muscle-type phosphofructokinase located on chromosome 1 (PFKM-CH1), was performed in 38 clinically diagnosed Down syndrome patients and 178 normal controls.</p><p><b>RESULTS</b>The ratios of PFKM-CH1/PFKL-CH21 products were 1.40 +/- 0.367 (mean +/- SD) and 0.46 +/- 0.21 (mean +/- SD) for disomy 21 and trisomy 21, respectively. The difference between these two groups was statistically significant (P<0.001).</p><p><b>CONCLUSION</b>This approach has proven to be a practical and direct method for the detection of trisomy 21 and may also be applied to the detection of the extra piece of 21q involved in translocation-type of Down syndrome.</p>

Effects of insulin and actin on phosphofructokinase activity and cellular distribution in skeletal muscle

Neste trabalho, nós relatamos evidencias de que a associação entre fosfofrutocinase e F-actina pode ser afetada por estímulos pela insulina em homogeneizados de músculo esquelético de coelho e que esta associação pode ser um mecanismo de regulação da fosfofrutocinase. Através de tecnicas de co-sedimentação, nós observamos que em tecidos estimulados pela insulina, aproximadamente 70% da atividade fosfofrutocinásica esta co-localizada a fração enriquecida com actina, contra 28% no controle. Este fenômeno é acompanhado por um aumento de 100% na atividade específica da fosfofrutocinase em homogeneizados estimulados. F-actina purificada causou um aumento de 230% na atividade da fosfofrutocinase e alterou seus parâmetros cinéticos. A presença de F-actina aumentou a afinidade da fosfofrutocinase pela frutose 6-fosfato, sem alterar, no entanto, a velocidade máxima (Vmax). Nós propomos que a modulação da distribuição celular da fosfofrutocinase pode ser um dos mecanismos de controle do fluxo glicolítico em músculos de mamíferos pela insulina.

An experimental study of the changes of rat hepatocytic glycolysis during hypoxia / 中华烧伤杂志

<p><b>OBJECTIVE</b>To investigate the effects of hypoxia on the glycolysis in cultured rat hepatocytes.</p><p><b>METHODS</b>Mixed gas with different concentrations of O(2), CO(2) and N(2) was prepared for the in vitro culture of normal rat hepatocytes. The cell strains were set to be A, B, C groups, which were observed at 1, 2, 4, 8 and 16 hours after hypoxia with normal hepatocytes as the control. Biochemical methods were employed to determine the activities of the key enzymes during hepatocytic glycolysis such as hexokinase (HK), phosphofructokinase (PFK), pyruvate kinase (PK), lactate dehydrogenase (LDH) and the change of the content of lactic acid (LA) in the culture fluid.</p><p><b>RESULTS</b>(1) The LDH activity of the rat hepatocytes increased significantly at all the time points of hypoxia in A and B groups when compared with that in control group (P < 0.05), while the activity increased obviously in C group since 2 hours after hypoxia (P < 0.05). (2) The HK activity of the cells in A group increased significantly at 1, 2, 4 and 16 hours after hypoxia and that in B and C groups increased obviously at 1 hour when compared with control group (P < 0.05). While the cellular PFK activity in A group increased markedly at 1 and 4 hours after hypoxia and that in B and C groups increased evidently at 4 hours after hypoxia (P < 0.05). The cellular PK activity in all the three groups increased at all the hypoxic time points (P < 0.05). (3) The cellular LA content in A and B groups began to increase since 2 hours and that in C group did so since 4 hours after hypoxia and increased along with the time lapse (P < 0.05).</p><p><b>CONCLUSION</b>hypoxia might initiate glycolysis.</p>