OBJECTIVES: Endothelium-dependent vasodilation dysfunction is the pathological basis of diabetic macroangiopathy. The utilization and adaptation of endothelial cells to high glucose determine the functional status of endothelial cells. Glycolysis pathway is the major energy source for endothelial cells. Abnormal glycolysis plays an important role in endothelium-dependent vasodilation dysfunction induced by high glucose. Pyruvate kinase isozyme type M2 (PKM2) is one of key enzymes in glycolysis pathway, phosphorylation of PKM2 can reduce the activity of pyruvate kinase and affect the glycolysis process of glucose. TEPP-46 can stabilize PKM2 in its tetramer form, reducing its dimer formation and phosphorylation. Using TEPP-46 as a tool drug to inhibit PKM2 phosphorylation, this study aims to explore the impact and potential mechanism of phosphorylated PKM2 (p-PKM2) on endothelial dependent vasodilation function in high glucose, and to provide a theoretical basis for finding new intervention targets for diabetic macroangiopathy. METHODS: The mice were divided into 3 groups: a wild-type (WT) group (a control group, C57BL/6 mice) and a db/db group (a diabetic group, db/db mice), which were treated with the sodium carboxymethyl cellulose solution (solvent) by gavage once a day, and a TEPP-46 group (a treatment group, db/db mice+TEPP-46), which was gavaged with TEPP-46 (30 mg/kg) and sodium carboxymethyl cellulose solution once a day. After 12 weeks of treatment, the levels of p-PKM2 and PKM2 protein in thoracic aortas, plasma nitric oxide (NO) level and endothelium-dependent vasodilation function of thoracic aortas were detected. High glucose (30 mmol/L) with or without TEPP-46 (10 μmol/L), mannitol incubating human umbilical vein endothelial cells (HUVECs) for 72 hours, respectively. The level of NO in supernatant, the content of NO in cells, and the levels of p-PKM2 and PKM2 protein were detected. Finally, the effect of TEPP-46 on endothelial nitric oxide synthase (eNOS) phosphorylation was detected at the cellular and animal levels. RESULTS: Compared with the control group, the levels of p-PKM2 in thoracic aortas of the diabetic group increased (P<0.05). The responsiveness of thoracic aortas in the diabetic group to acetylcholine (ACh) was 47% lower than that in the control group (P<0.05), and that in TEPP-46 treatment group was 28% higher than that in the diabetic group (P<0.05), while there was no statistically significant difference in the responsiveness of thoracic aortas to sodium nitroprusside (SNP). Compared with the control group, the plasma NO level of mice decreased in the diabetic group, while compared with the diabetic group, the phosphorylation of PKM2 in thoracic aortas decreased and the plasma NO level increased in the TEPP-46 group (both P<0.05). High glucose instead of mannitol induced the increase of PKM2 phosphorylation in HUVECs and reduced the level of NO in supernatant (both P<0.05). HUVECs incubated with TEPP-46 and high glucose reversed the reduction of NO production and secretion induced by high glucose while inhibiting PKM2 phosphorylation (both P<0.05). At the cellular and animal levels, TEPP-46 reversed the decrease of eNOS (ser1177) phosphorylation induced by high glucose (both P<0.05). CONCLUSIONS p-PKM2 may be involved in the process of endothelium-dependent vasodilation dysfunction in Type 2 diabetes by inhibiting p-eNOS (ser1177)/NO pathway.
Animals ; Humans ; Mice ; Carboxymethylcellulose Sodium/pharmacology* ; Diabetes Mellitus, Type 2/metabolism* ; Endothelium, Vascular/metabolism* ; Glucose/metabolism* ; Human Umbilical Vein Endothelial Cells ; Mice, Inbred C57BL ; Nitric Oxide/metabolism* ; Nitric Oxide Synthase Type III/metabolism* ; Phosphorylation ; Pyruvate Kinase/metabolism* ; Vasodilation

OBJECTIVE: To investigate the effect of glycolytic enzyme pyruvate kinase type 2 (PKM2) on the proliferation and apoptosis of human leukemia HL-60 cells. METHODS: si-PKM2 plasmid was transfected into HL-60 cells (set as si-PKM2 group), and blank vector transfected cells were set as control group (si-Ctl group). The expression levels of PKM2 mRNA and protein in si-Ctl group and si-PKM2 group were detected by RT-qPCR and Western blot. CCK-8 cell detection kit was used to detect the proliferation ability of the cells in the two groups. Flow cytometry was used to detect the changes of cell cycle and apoptosis. Western blot and RT-qPCR were used to detect the changes of p-Akt and p-mTOR protein levels in PI3K/Akt/mTOR signaling pathway and the changes of glycolysis-related mRNA levels of the cells in the two groups. The changes in glucose consumption and lactic acid production of the cells were assayed. Over expressed PKM2, HL-60 cells were treated with PI3K inhibitor LY294002 or galactose, the changes in cell proliferation ability, cell cycle and apoptosis, as well as changes in glucose consumption and lactic acid production were detected. RESULTS: Interfered by si-PKM2, mRNA and protein levels of PKM2 in si-PKM2 group significantly decreased, and proliferation ability of the cells was also reduced (P<0.05). After PKM2 knockdown, the cells were significantly blocked at G CONCLUSION PKM2 knockdown can inhibit the proliferation and induce apoptosis of HL-60 cells, and its molecular mechanism may be related to the PKM2-mediated PI3K/Akt/mTOR-glycolysis, which suggesting that PKM2 may serve as a molecular target for the prevention and treatment of leukemia.
Apoptosis ; Cell Proliferation ; Glycolysis ; Humans ; Phosphatidylinositol 3-Kinases/metabolism* ; Pyruvate Kinase

Anemia, Hemolytic, Congenital Nonspherocytic ; Erythrocytes ; Humans ; Pyruvate Kinase/deficiency* ; Pyruvate Metabolism, Inborn Errors

OBJECTIVETo evaluate the feasibility of genetic and prenatal diagnosis for a family affected with pyruvate kinase deficiency (PKD).

METHODSTargeted sequence capture and high-throughput sequencing technology was used to detect the exons and exon-intron boundaries of the PKLR gene in a clinically suspected PKD patient. Meanwhile, the genotype of the pedigree was validated by Sanger sequencing. Prenatal genetic diagnosis was performed by amniotic fluid sampling after genotype of the mother of the proband was determined.

RESULTSThe proband was found to harbor double heterozygous mutations, c.661G>A (Asp221Asn) and c.1528C>T (Arg510Ter), which resulted in amino acid substitution Asp221Asn and Arg510Ter. Such mutations were confirmed by Sanger sequencing. The mother and father of the proband were detected to have respectively carried c.1528C>T (Arg510Ter) and c.661G>A (Asp221Asn) mutation. The fetus was found to have carried the same mutations as the proband. Following selected abortion, analysis of fetal tissue was consistent with the result of prenatal diagnosis.

CONCLUSIONThe compound mutations of c.661G>A and c.1528C>T of PKLR gene probably underlie the PKD in the family. Prenatal diagnosis of the mutations analysis can facilitate detection of affected fetus in time.

Adult ; Anemia, Hemolytic, Congenital Nonspherocytic ; embryology ; enzymology ; genetics ; Base Sequence ; Child, Preschool ; DNA Mutational Analysis ; Exons ; Female ; Genotype ; Humans ; Male ; Molecular Sequence Data ; Mutation ; Pedigree ; Pregnancy ; Prenatal Diagnosis ; Pyruvate Kinase ; deficiency ; genetics ; metabolism ; Pyruvate Metabolism, Inborn Errors ; embryology ; enzymology ; genetics

OBJECTIVETo explore the molecular mechanism of erythrocyte pyruvate kinase deficiency (PKD).

METHODSTargeted sequence capture and next-generation sequencing (NGS) were used to detect the regions of exon and exon-intron boundarie of PKLR gene in a clinical suspected PKD patient. The protein function of mutant gene was forecasted by the SIFT and PolyPhen-2 databank, after the mutation of PKLR gene in the patient was detected by the NGS technology, its genotype was confirmed by Sanger sequencing.

RESULTSThe patient was found to have peculiar double heterozygous mutations: 661 G>A (Asp221Asn) of exon 5 and 1528 C>T (Arg510Ter) of exon 10, resulting in amino acid substitution Asp221Asn and Arg510Ter, these mutations were also further confirmed by Sanger sequencing. The complex mutations were infrequent and each of them was able to cause diseases.

CONCLUSIONThe complex mutations of both 661 G>A and 1528 C>T of PKLR gene are the molecular mechanism of PKD. Simultaneous existance of above-mentioned complex mutations in PDK patient was never been previously reported at home and abroad.

Anemia, Hemolytic, Congenital Nonspherocytic ; genetics ; Exons ; Genotype ; High-Throughput Nucleotide Sequencing ; Humans ; Introns ; Mutation ; Pyruvate Kinase ; deficiency ; genetics ; Pyruvate Metabolism, Inborn Errors ; genetics

OBJECTIVETo screen potential mutation and explore the underlying mechanism for a consanguineous pedigree featuring pyruvate kinase (PK) deficiency.

METHODSThe red blood cell pyruvate kinase activities of all family members were detected. All the exons and intron-exon boundaries of the PKLR gene for the proband were amplified and analyzed by direct sequencing. Restriction endonuclease enzymes were used to identify the presence of mutations of all family members.

RESULTSThe pyruvate kinase activities were 5.89 U/g Hb in the proband, 3.45, 6.54, 8.87, 7.89, 9.32 U/g Hb in his younger sister, father, mother, grandmother and elder aunt, respectively. The homozygous missense mutation of T>C transition at position 941 in exon 7 of PKLR gene resulted to a Ile314Thr substitution in the proband, and mutant alleles were identified at the level of RNA transcript by cDNA sequence analysis. His younger sister was also homozygous for Ile314Thr. Heterozygosity for Ile314Thr was confirmed in his grandmother, parents and elder aunt.

CONCLUSIONIle314Thr homozygous missense mutation in exon 7 of PKLR is the molecular mechanism of pyruvate kinase deficiency in this family.

Anemia, Hemolytic, Congenital Nonspherocytic ; genetics ; Child, Preschool ; Female ; Humans ; Male ; Pedigree ; Point Mutation ; Pyruvate Kinase ; deficiency ; genetics ; Pyruvate Metabolism, Inborn Errors ; genetics

Pyruvate kinase catalyzes the rate-limiting final step of glycolysis, generating adenosine triphosphate (ATP) and pyruvate. The M2 tumor-specific isoform of pyruvate kinase (PKM2) promotes glucose uptake and lactate production in the presence of oxygen, known as aerobic glycolysis or the Warburg effect. As recently reported in Nature, PKM2, besides its metabolic function, has a nonmetabolic function in the direct control of cell cycle progression by activating β-catenin and inducing expression of the β-catenin downstream gene CCND1(encoding for cyclin D1). This nonmetabolic function of PKM2 is essential for epidermal growth factor receptor (EGFR) activation-induced tumorigenesis.
Animals ; Cell Cycle ; Cell Proliferation ; Cell Transformation, Neoplastic ; Cyclin D1 ; metabolism ; Glycolysis ; Humans ; Isoenzymes ; metabolism ; Neoplasms ; metabolism ; pathology ; Pyruvate Kinase ; metabolism ; Receptor, Epidermal Growth Factor ; metabolism ; beta Catenin ; metabolism

OBJECTIVETo evaluate the clinical significance of blood and fecal expression of tumor M2-pyruvate kinase (Tumor M2-PK) in patients with colorectal cancer.

METHODSWith 22 healthy subjects as controls, 44 patients with CRC were examined for tumor M2-PK in serum and fecal samples using a sandwich enzyme immunoassay.

RESULTSThe sensitivity of serum and fecal tumor M2-PK for detecting CRC was 59.1% and 63.6% with a specificity of 86.4% and 81.8%, respectively. The serum and fecal levels of tumor M2-PK showed a significant correlation in CRC patients.

CONCLUSIONTumor M2-PK has good sensitivity and specificity in the diagnosis of CRC.

Biomarkers, Tumor ; metabolism ; Case-Control Studies ; Colorectal Neoplasms ; blood ; metabolism ; Feces ; enzymology ; Female ; Humans ; Male ; Pyruvate Kinase ; blood ; metabolism

OBJECTIVETo explore cell culture techniques for amplification of oval cells with preservation simultaneously of the stem cell characteristics.

METHODSOval cell line OC3 was cultured in RPMI 1640 supplemented with 15% fetal bovine serum and 20 µg/L EGF. Cells were harvested every 5 passages and were examined with biomarkers including OV-6, c-kit, gamma-glutamyl transpeptidase, placental form of glutathione-S-transferase (GST-P), pyruvate kinase M₂, pyruvate kinase L and albumin using techniques including RT-PCR, immunocytochemistry, and enzymo-cytochemistry.

RESULTSOC3 cell lines could be amplified abundantly in-vitro associating with expression of infant liver cell markers at various level, including OV-6, c-kit, gamma-glutamyl transpeptidase, GST-P, pyruvate kinase M₂, but no expression of mature hepatocyte markers detected including pyruvate kinase L and albumin.

CONCLUSIONSAmplification of OC3 cells with preservation of the stem cell phenotype and high proliferation index can be achieved up to the 79(th) passages by culturing in RPMI 1640 supplemented with 15% fetal bovine serum and 20 µg/L EGF.

Animals ; Antigens, Differentiation ; metabolism ; Cell Culture Techniques ; Cell Differentiation ; Cell Line ; Culture Media ; Glutathione Transferase ; metabolism ; Hepatocytes ; cytology ; metabolism ; Liver ; cytology ; growth & development ; Phenotype ; Proto-Oncogene Proteins c-kit ; metabolism ; Pyruvate Kinase ; metabolism ; Rats ; Rats, Sprague-Dawley ; Stem Cells ; cytology ; metabolism

OBJECTIVETo investigate the influence of microtubule intervention drugs on glycolytic key enzymes in myocardial cells after hypoxia.

METHODSThe primary passage of cultured myocardial cells from neonatal rats were divided into A group (with hypoxia), B group (with hypoxia and administration of l0 micromol/L colchicine), C group (with hypoxia and administration of 5 micromol/L taxol), D group (with hypoxia and administration of 10 micromol/L taxol), E group (with hypoxia and administration of 15 micromol/L taxol). The morphology of microtubule was observed with laser scanning microscope (LSM). The cell vitality was assayed by cell counting kit (CCK). The activities of hexokinase (HK), pyruvate kinase (PK), phosphofructokinase (PFK) and lactate dehydrogenase (LDH) were assayed with colorimetry.

RESULTSIn group B and E, the microtubule structure was damaged heavily, and the cell vitality was decreased significantly [The cell vitality was (89.99 +/- 3.47)% in B group and (84.56 +/- 6.61)% in E group, respectively, at 1.0 post hypoxia hour (PHH), and hoth values were obviously lower than that in A group (97.44 +/- 1.76)%, P < 0.01]. The HK, PK and PFK activities decreased obviously. The activities of HK, PK and PFK in group C were similar to those of the A group. Compared with that in other groups, the degree of damage of microtubule structure in D group was milden. The activities of HK, PK and PFK in D group during 0.5 - 6.0 PHH were significantly higher than those in A group. The activity of LDH in each group was increased after hypoxia.

CONCLUSIONProper concentration of microtubule-stabilizing drugs can alleviate the damages to microtubule structure, and enhance the activity of glycolytic key enzymes of myocardial cells at early stage of hypoxia.

Animals ; Cell Hypoxia ; Cells, Cultured ; Glycolysis ; drug effects ; Hexokinase ; metabolism ; L-Lactate Dehydrogenase ; metabolism ; Microtubules ; drug effects ; metabolism ; Myocytes, Cardiac ; enzymology ; metabolism ; Phosphofructokinase-1 ; metabolism ; Pyruvate Kinase ; metabolism ; Rats ; Rats, Sprague-Dawley