Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 31
Filter
Add more filters

Country/Region as subject
Affiliation country
Publication year range
1.
J Infect Chemother ; 30(2): 111-117, 2024 Feb.
Article in English | MEDLINE | ID: mdl-37717607

ABSTRACT

INTRODUCTION: This study aimed to determine the impact of augmented renal clearance (ARC) on anticoagulation therapy in critically ill patients with coronavirus disease 2019 (COVID-19). METHODS: This retrospective cohort study included adult patients with severe COVID-19 with ARC who had been treated at our hospital between 2020 and 2021. We measured the estimated glomerular filtration rate calculated by the Chronic Kidney Disease Epidemiology Collaboration formula (eGFRCKD-EPI) every morning, and ARC condition was defined as eGFRCKD-EPI ≥ 130 mL/min/1.73 m2. Multivariate regression analysis with Huber-White sandwich estimator was performed to examine the association of unfractionated heparin (UH) dosage between blood test timings with activated partial thromboplastin time (APTT) compared with and without ARC. RESULTS: We identified 38 enrolled patients: seven and 31 in the ARC and non-ARC groups, respectively. In the ARC coexisting condition, a higher dose of UH, which corresponded to the total dose in 24 h from the previous day, was required to achieve the same APTT prolongation, with a significant difference (p < 0.001). CONCLUSIONS: Our study suggests that careful monitoring and consideration of higher UH doses in critically ill patients with COVID-19 is necessary because anticoagulation failure can occur during ARC.


Subject(s)
COVID-19 , Renal Insufficiency, Chronic , Adult , Humans , Heparin/therapeutic use , Retrospective Studies , Critical Illness , Renal Insufficiency, Chronic/chemically induced , Anticoagulants/therapeutic use , Creatinine
2.
Angew Chem Int Ed Engl ; 62(23): e202303657, 2023 Jun 05.
Article in English | MEDLINE | ID: mdl-37000460

ABSTRACT

The C-F bond of acyl fluorides can be cleaved and added across tethered alkenes in the presence of a cationic rhodium(I) tetrafluoroborate catalyst. This 1,2-carbofluorination reaction offers a powerful method for the synthesis of tertiary alkyl fluoride derivatives with an atom economy of 100 %. Mechanistic studies indicate that the concerted action of a rhodium cation and a tetrafluoroborate anion is key for the success of this catalytic cleavage and formation of C-F bonds in a controlled manner.

3.
Genes Cells ; 26(8): 570-582, 2021 Aug.
Article in English | MEDLINE | ID: mdl-34033175

ABSTRACT

During periods of crisis, cells must compensate to survive. To this end, cells may need to alter the subcellular localization of crucial proteins. Here, we show that during starvation, VCP, the most abundant soluble ATPase, relocalizes and forms aggregate-like structures at perinuclear regions in PC3 prostate cancer cells. This movement is associated with a lowered metabolic state, in which mitochondrial activity and ROS production are reduced. VCP appears to explicitly sense glutamine levels, as removal of glutamine from complete medium triggered VCP relocalization and its addition to starvation media blunted VCP relocalization. Cells cultured in Gln(+) starvation media exhibited uniformly distributed VCP in the cytoplasm (free VCP) and underwent ferroptotic cell death, which was associated with a decrease in GSH levels. Moreover, the addition of a VCP inhibitor, CB-5083, in starvation media prevented VCP relocalization and triggered ferroptotic cell death. Likewise, expression of GFP-fused VCP proteins, irrespective of ATPase activities, displayed free VCP and triggered cell death during starvation. These results indicate that free VCP is essential for the maintenance of mitochondrial function and that PC3 cells employ a strategy of VCP self-aggregation to suppress mitochondrial activity in order to escape cell death during starvation, a novel VCP-mediated survival mechanism.


Subject(s)
Ferroptosis , Glutamine/deficiency , Glutathione/metabolism , Mitochondria/metabolism , Prostatic Neoplasms/metabolism , Valosin Containing Protein/metabolism , Humans , Male , PC-3 Cells , Protein Transport
4.
Genes Cells ; 24(11): 688-704, 2019 Nov.
Article in English | MEDLINE | ID: mdl-31495058

ABSTRACT

In Chinese medicine, herbal medicine is commonly used to treat individuals suffering from many types of diseases. We thus expected that some herbal medicines would contain promising compounds for cancer chemotherapy. Indeed, we found that Sanguisorba officinalis extracts strongly inhibit the growth of B16F10 melanoma cells, and we identified ellagic acid (EA) as the responsible ingredient. B16F10 cells treated with EA exhibited strong G1 arrest accompanied by accumulation of p53, followed by inactivation of AKT. Addition of a PTEN inhibitor, but not a p53 inhibitor, abrogated the EA-induced AKT inactivation and G1 arrest. The PTEN inhibitor also diminished EA-induced p53 accumulation. Furthermore, EA apparently increased the protein phosphatase activity of PTEN, as demonstrated by the reduced phosphorylation level of FAK, a protein substrate of PTEN. Furthermore, an in vitro PTEN phosphatase assay on PIP3 showed the direct modulation of PTEN activity by EA. These results suggest that EA functions as an allosteric modulator of PTEN, enhancing its protein phosphatase activity while inhibiting its lipid phosphatase activity. It is notable that a combination of EA and cisplatin, a widely used chemotherapy agent, dramatically enhanced cell death in B16F10 cells, suggesting a promising strategy in chemotherapy.


Subject(s)
Antineoplastic Agents/pharmacology , Ellagic Acid/pharmacology , G1 Phase Cell Cycle Checkpoints/drug effects , Melanoma/drug therapy , PTEN Phosphohydrolase/metabolism , Plant Extracts/pharmacology , Sanguisorba/chemistry , Antineoplastic Agents/chemistry , Cell Death/drug effects , Cell Line, Tumor , Cisplatin/pharmacology , Drug Therapy, Combination , Drugs, Chinese Herbal/pharmacology , Ellagic Acid/chemistry , Ellagic Acid/isolation & purification , Focal Adhesion Kinase 1 , Herbal Medicine , Humans , PTEN Phosphohydrolase/drug effects , Phosphorylation , Proto-Oncogene Proteins c-akt/metabolism , Signal Transduction/drug effects , Tumor Suppressor Protein p53/metabolism
5.
Neural Comput ; 31(12): 2432-2491, 2019 12.
Article in English | MEDLINE | ID: mdl-31614101

ABSTRACT

Distance metric learning has been widely used to obtain the optimal distance function based on the given training data. We focus on a triplet-based loss function, which imposes a penalty such that a pair of instances in the same class is closer than a pair in different classes. However, the number of possible triplets can be quite large even for a small data set, and this considerably increases the computational cost for metric optimization. In this letter, we propose safe triplet screening that identifies triplets that can be safely removed from the optimization problem without losing the optimality. In comparison with existing safe screening studies, triplet screening is particularly significant because of the huge number of possible triplets and the semidefinite constraint in the optimization problem. We demonstrate and verify the effectiveness of our screening rules by using several benchmark data sets.

6.
Chem Pharm Bull (Tokyo) ; 67(6): 546-555, 2019.
Article in English | MEDLINE | ID: mdl-31155560

ABSTRACT

We report a three-dimensional quantitative structure-activity relationship (3D-QSAR) analysis of CDK2 inhibitors using fragment molecular orbital (FMO) calculations and partial least squares (PLS) regression. In our analysis, fragment binding energies of individual amino acids and fragment binding energy of a single ligand in a protein-ligand complex are evaluated by FMO calculations and used as descriptors in PLS regression to estimate biological activities of the ligands. The analysis was applied to the system of CDK2 protein and its inhibitors and the effectiveness of the method was tested. Application of the 3D-QSAR model demonstrated that it offered good predictive ability and was able to predict not only biological activity of ligands but also identify important amino acid residues which could be targeted in order to improve ligand activity.


Subject(s)
Cyclin-Dependent Kinase 2/antagonists & inhibitors , Protein Kinase Inhibitors/chemistry , Quantitative Structure-Activity Relationship , Binding Sites , Least-Squares Analysis , Ligands , Molecular Docking Simulation , Protein Binding , Protein Structure, Tertiary , Thermodynamics
7.
J Org Chem ; 83(15): 7886-7899, 2018 08 03.
Article in English | MEDLINE | ID: mdl-29847953

ABSTRACT

As promising antifungal agents, the eight stereoisomers of eushearilide, including the natural compound, were synthesized relying on an asymmetric Mukaiyama aldol reaction, Julia-Kocienski olefination, and Shiina macrolactonization. Moreover, their in vitro antimicrobial activities against some fungi and bacteria were evaluated by the disk-diffusion method, which revealed that not only natural eushearilide but also its stereoisomers exhibited significant antimicrobial activity against a variety of fungi and bacteria.


Subject(s)
Anti-Infective Agents/chemistry , Anti-Infective Agents/pharmacology , Macrolides/chemistry , Macrolides/pharmacology , Phosphorylcholine/analogs & derivatives , Anti-Infective Agents/chemical synthesis , Chemistry Techniques, Synthetic , Cyclization , Macrolides/chemical synthesis , Phosphorylcholine/chemical synthesis , Phosphorylcholine/chemistry , Phosphorylcholine/pharmacology , Stereoisomerism
8.
Chem Pharm Bull (Tokyo) ; 66(4): 399-409, 2018.
Article in English | MEDLINE | ID: mdl-29607905

ABSTRACT

We recently reported that the Gibbs free energy of hydrolytic water molecules (ΔGwat) in acyl-trypsin intermediates calculated by hydration thermodynamics analysis could be a useful metric for estimating the catalytic rate constants (kcat) of mechanism-based reversible covalent inhibitors. For thorough evaluation, the proposed method was tested with an increased number of covalent ligands that have no corresponding crystal structures. After modeling acyl-trypsin intermediate structures using flexible molecular superposition, ΔGwat values were calculated according to the proposed method. The orbital energies of antibonding π* molecular orbitals (MOs) of carbonyl C=O in covalently modified catalytic serine (Eorb) were also calculated by semi-empirical MO calculations. Then, linear discriminant analysis (LDA) was performed to build a model that can discriminate covalent inhibitor candidates from substrate-like ligands using ΔGwat and Eorb. The model was built using a training set (10 compounds) and then validated by a test set (4 compounds). As a result, the training set and test set ligands were perfectly discriminated by the model. Hydrolysis was slower when (1) the hydrolytic water molecule has lower ΔGwat; (2) the covalent ligand presents higher Eorb (higher reaction barrier). Results also showed that the entropic term of hydrolytic water molecule (-TΔSwat) could be used for estimating kcat and for covalent inhibitor optimization; when the rotational freedom of the hydrolytic water molecule is limited, the chance for favorable interaction with the electrophilic acyl group would also be limited. The method proposed in this study would be useful for screening and optimizing the mechanism-based reversible covalent inhibitors.


Subject(s)
Molecular Dynamics Simulation , Quantum Theory , Serine Proteases/metabolism , Serine Proteinase Inhibitors/pharmacology , Thermodynamics , Discriminant Analysis , Serine Proteinase Inhibitors/chemistry , Water/chemistry
9.
Molecules ; 23(10)2018 Oct 18.
Article in English | MEDLINE | ID: mdl-30340368

ABSTRACT

Some point mutations in ß-glucocerebrosidase cause either improper folding or instability of this protein, resulting in Gaucher disease. Pharmacological chaperones bind to the mutant enzyme and stabilize this enzyme; thus, pharmacological chaperone therapy was proposed as a potential treatment for Gaucher disease. The binding affinities of α-1-C-alkyl 1,4-dideoxy-1,4-imino-d-arabinitol (DAB) derivatives, which act as pharmacological chaperones for ß-glucocerebrosidase, abruptly increased upon elongation of their alkyl chain. In this study, the primary causes of such an increase in binding affinity were analyzed using protein⁻ligand docking and molecular dynamics simulations. We found that the activity cliff between α-1-C-heptyl-DAB and α-1-C-octyl-DAB was due to the shape and size of the hydrophobic binding site accommodating the alkyl chains, and that the interaction with this hydrophobic site controlled the binding affinity of the ligands well. Furthermore, based on the aromatic/hydrophobic properties of the binding site, a 7-(tetralin-2-yl)-heptyl-DAB compound was designed and synthesized. This compound had significantly enhanced activity. The design strategy in consideration of aromatic interactions in the hydrophobic pocket was useful for generating effective pharmacological chaperones for the treatment of Gaucher disease.


Subject(s)
Gaucher Disease/drug therapy , Glucosylceramidase/antagonists & inhibitors , Imino Sugars/chemistry , Sugar Alcohols/chemistry , Binding Sites , Enzyme Stability/drug effects , Glucosylceramidase/chemistry , Humans , Imino Sugars/therapeutic use , Ligands , Molecular Chaperones/chemistry , Molecular Docking Simulation , Molecular Dynamics Simulation , Mutant Proteins/chemistry , Point Mutation , Protein Binding , Sugar Alcohols/antagonists & inhibitors , Sugar Alcohols/therapeutic use
10.
J Phys Ther Sci ; 30(5): 675-679, 2018 May.
Article in English | MEDLINE | ID: mdl-29765178

ABSTRACT

[Purpose] Medial longitudinal arch (MLA) height is associated with various injuries and diseases and gender differences, if any. This study aimed to examine factors affecting the MLA height associated with gender differences in healthy subjects with no orthopedic disorders. [Subjects and Methods] This study included 36 healthy adults (19 males, 17 females; mean age, 21.8 ± 3.6 years; body mass index, 21.1 ± 2.0 kg/m2). Their height, body weight, foot length, muscle strength of the tibialis posterior muscle (TPM), toe-gripping strength, hallux valgus angle, inversion microdactylia angle, angle of leg-heel alignment, femoro-tibial angle, and navicular height were measured. Correlation between the ratio of arch height and other measurement parameters was examined. [Results] In females, the ratio of arch height was significantly positively correlated with muscle strength of the TPM and toe-gripping strength and negatively correlated with the hallux valgus angle and the leg-heel alignment, whereas in males, only a positive correlation between the ratio of arch height and muscle strength of the TPM was observed. [Conclusion] These results reveal that etiological mechanisms determining MLA height are different between males and females. Overall, the present results indicate that further studies identifying causes of MLA height variation must include gender-based analysis.

11.
J Vet Med Sci ; 86(9): 920-924, 2024 Sep 01.
Article in English | MEDLINE | ID: mdl-38987179

ABSTRACT

We examined the relationship between inherited motor-related conformation and orientation of facial hair whorls in Japanese Kiso horses. Eleven horses were divided into clockwise, counterclockwise, and radial groups according to facial hair whorls. We placed six markers on anatomical landmarks of each lateral side in a horse and measured the height of the landmarks, the distance between adjacent landmarks, and the angle of the adjacent landmarks. In the counterclockwise group, the horses tended to exhibit higher values on the left side than on the right side, and the comparison of the height of landmarks revealed a significant difference between both sides. Therefore, the orientation of facial hair whorls may suggest the tendency of motor-related conformation, at least in counterclockwise group.


Subject(s)
Animal Fur , Animals , Female , Male , Animal Fur/anatomy & histology , Horses/anatomy & histology
12.
Animals (Basel) ; 14(4)2024 Feb 08.
Article in English | MEDLINE | ID: mdl-38396539

ABSTRACT

This study investigates the non-invasive monitoring of the endocrine ovarian activities of captive female golden takins (Budorcas taxicolor bedfordi) based on long-term fecal sex steroid hormone metabolite dynamics. Fecal progesterone (P4) metabolite dynamics were monitored in nine females for 0.5-15 years between 2004 and 2022. Fecal estradiol-17ß (E2) and estrone (E1) metabolites were measured during certain estrous cycles, and fecal E1 metabolite concentrations were measured during all gestation periods. The breeding season of the captive animals was mainly between May and December, and they were polyestrous animals whose breeding season begins during the long-day period. The onset of the breeding season occurred slightly earlier as age increased. The mean age (±SD) at puberty based on fecal P4 metabolite dynamics was 4.1 ± 2.9 years. The first conception ages ranged from 2.3-10.2 years. The mean estrous cycle period (±SEM) was 25.4 ± 1.1 days, and mounting and mating occurred in periods of low fecal P4 metabolite levels during the breeding season. The mean gestation period (±SD) from the estimated mating date to the calving date was 253.9 ± 5.7 days, and the fecal P4 metabolite distribution during pregnancy was bimodal. Fecal estrone metabolite levels gradually increased 21 weeks before delivery, peaked during the week of delivery, and then markedly decreased in the first week after delivery. Estrus resumed in the first April-August period after delivery (mean ± SD; 103.5 ± 40.9 days) or in May of the year after delivery (421.0 ± 16.5 days). This study revealed that the estrous cycle and pregnancy of female golden takins can be determined by fecal progesterone metabolite dynamics and that fecal estrone metabolite dynamics increases toward parturition and are useful for predicting the date of delivery. This endocrinological information is important for planned breeding efforts for the golden takins.

13.
J Hazard Mater ; 459: 132251, 2023 10 05.
Article in English | MEDLINE | ID: mdl-37591166

ABSTRACT

Dehalococcoides is a functional microorganism that completely dechlorinates trichloroethene (TCE). Augmentation with pure Dehalococcoides is important for reducing environmental disturbances that accompany bioaugmentation. However, the applicability of Dehalococcoides-bioaugmentation to contaminated soils is unclear. In this study, seven low-carbon energy sources (methanol, formate, acetate, ethanol, lactate, citrate, and benzoate) were used as electron donors for Dehalococcides to evaluate its applicability in remediating TCE-contaminated soils. Soil microcosms supplemented with ethanol, formate, or lactate showed relatively high dechlorination activity within 111-180 days. The functional gene profiles predicted by PICRUSt2 from 16 S rRNA gene sequences were similar in the proportions of dehydrogenases, which initiate electron donor oxidation, in all soils and did not seem to reflect Dehalococcoides-bioaugmentation applicability. Soils with higher organic matter content (>3.2%; dry weight base) and protein concentration (>1.6 µg/mL) supported complete dechlorination. These results suggest that organic matter and nutrient availability mainly affect successful TCE dechlorination in Dehalococcoides-augmented soils. The study offers significant experimental support for comprehending the suitability of low-carbon energy sources in successful bioaugmentation, aiming to mitigate environmental disturbances associated with the process.


Subject(s)
Dehalococcoides , Lactic Acid , Carbon , Ethanol , Formates , Nutrients
14.
Anat Histol Embryol ; 51(5): 602-610, 2022 Sep.
Article in English | MEDLINE | ID: mdl-35818997

ABSTRACT

The presence of transverse foramina in the axes of Japanese serows, a special national natural treasure in Japan, has been reported to be unstable, but other variations are unknown. In this study, we analysed the shape, cross-sectional area, length, and volume of the transverse foramen in the axes of 19 specimens using gross anatomy and computed tomography (CT) scan. There were four types in the transverse foramen: type 1, having the transverse foramina; type 2, having two cranial openings; type 3, sifting a caudal opening to the ventral side of the transverse process; and type 4, having no transverse foramina. Although the transverse foramina showed different types on the left and right sides in several specimens, there were no statistically significant differences in the length and volume. This variation may be related to running patterns of the vertebral artery penetrating the transverse foramina. Two goats without the transverse foramina were examined to infer a running pattern of the vertebral artery instead of Japanese serows. The vertebral artery in the goats branched in two directions (spinal and muscle), between the axis and the third cervical vertebra. This passage of the goat vertebral artery might be presumed in type 4 of Japanese serows. This study reveals the instability of the transverse foramina in the axes of Japanese serows and provides new data to compare the axes of other ruminants.


Subject(s)
Ruminants , Vertebral Artery , Animals , Cervical Vertebrae/anatomy & histology , Goats , Japan , Vertebral Artery/anatomy & histology
15.
J Med Chem ; 65(3): 2329-2341, 2022 02 10.
Article in English | MEDLINE | ID: mdl-35072486

ABSTRACT

In recent years, the function of pharmacological chaperones as a "thermodynamic stabilizer" has been attracting attention in combination therapy. The coadministration of a pharmacological chaperone and recombinant human acid α-glucosidase (rhGAA) leads to improved stability and maturation by binding to the folded state of the rhGAA and thereby promotes enzyme delivery. This study provides the first example of a strategy to design a high-affinity ligand toward lysosomal acid α-glucosidase (GAA) focusing on alkyl branches on 1-deoxynojirimycin (DNJ); 5-C-heptyl-DNJ produced a nanomolar affinity for GAA with a Ki value of 0.0047 µM, which is 13-fold more potent than DNJ. The protein thermal shift assay revealed that 10 µM 5-C-heptyl-DNJ increased the midpoint of the protein denaturation temperature (Tm) to 73.6 °C from 58.6 °C in the absence of the ligand, significantly improving the thermal stability of rhGAA. Furthermore, 5-C-heptyl-DNJ dose dependency increased intracellular GAA activities in Pompe patient's fibroblasts with the M519V mutation. The introduction of C5 alkyl branches on DNJ provides a new molecular strategy for pharmacological chaperone therapy for Pompe disease, which may lead to the development of higher-affinity and practically useful chaperones.


Subject(s)
1-Deoxynojirimycin/analogs & derivatives , 1-Deoxynojirimycin/pharmacology , Enzyme Inhibitors/pharmacology , alpha-Glucosidases/metabolism , Alkylation , Enzyme Inhibitors/chemical synthesis , Fibroblasts/metabolism , Glycogen Storage Disease Type II , Humans , Molecular Dynamics Simulation , Molecular Structure , Mutation , Protein Conformation/drug effects , Protein Stability/drug effects , Recombinant Proteins/drug effects , Recombinant Proteins/metabolism , alpha-Glucosidases/drug effects , alpha-Glucosidases/genetics
16.
Environ Microbiol Rep ; 13(6): 822-829, 2021 12.
Article in English | MEDLINE | ID: mdl-34632721

ABSTRACT

Conidial pigment is an important virulence factor in Aspergillus fumigatus, a human fungal pathogen. The biosynthetic gene cluster for 1,8-dihydroxynaphthalene (DHN)-melanin in A. fumigatus consists of six genes, alb1, ayg1, arp1, arp2, abr1 and abr2. In contrast to black DHN-melanin fungi such as Magnaporthe grisea, the polyketide synthase Alb1p in A. fumigatus produces naphthopyrone YWA1 instead of 1,3,6,8-THN (T4HN) and YWA1 is converted to T4HN by Ayg1p. The yeast transformant expressing Alb1p and Arp1p dehydratase produced an unknown compound which was identified to be a novel angular naphthopyrone named YWA3 formed from YWA1. In addition, the amount of YWA3 produced was much more than that of YWA2 formed by non-enzymatic dehydration from YWA1. To further analyse the reaction in vitro, Arp1p was overexpressed in E. coli and purified. Kinetic analysis revealed Km value of Arp1p for YWA1 to be 41 µM which is comparable with that of Ayg1p for YWA1 in conversion to T4HN. The complex structure modelling well explained the mechanism of YWA3 generation by the dehydration of angular YWA1 by Arp1p. These results indicated the possibility that polymerization of angular naphthopyrone YWA3 but not YWA2 could be involved in the characteristic bluish-green conidial pigmentation of A. fumigatus.


Subject(s)
Aspergillus fumigatus , Melanins , Aspergillus fumigatus/genetics , Aspergillus fumigatus/metabolism , Escherichia coli/metabolism , Fungal Proteins/genetics , Fungal Proteins/metabolism , Humans , Hydro-Lyases , Kinetics
17.
Front Med (Lausanne) ; 8: 791309, 2021.
Article in English | MEDLINE | ID: mdl-35004758

ABSTRACT

Glycocalyx is present on the surface of healthy endothelium, and the concentration of serum syndecan-1 can serve as an injury marker. This study aimed to assess endothelial injury using serum syndecan-1 as a marker of endothelial glycocalyx injury in patients who underwent hemodialysis. In this single-center, retrospective, observational study, 145 patients who underwent hemodialysis at the Gifu University Hospital between March 2017 and December 2019 were enrolled. The median dialysis period and time were 63 months and 3.7 h, respectively. The serum syndecan-1 concentration significantly increased from 124.6 ± 107.8 ng/ml before hemodialysis to 229.0 ± 138.1 ng/ml after hemodialysis (P < 0.001). Treatment with anticoagulant nafamostat mesylate inhibited hemodialysis-induced increase in the levels of serum syndecan-1 in comparison to unfractionated heparin. Dialysis time and the change in the syndecan-1 concentration were positively correlated. Conversely, the amount of body fluid removed and the changes in the syndecan-1 concentration were not significantly correlated. The reduction in the amount of body fluid removed and dialysis time inhibited the change in the syndecan-1 levels before and after hemodialysis. In conclusion, quantitative assessment of the endothelial glycocalyx injury during hemodialysis can be performed by measuring the serum syndecan-1 concentration, which may aid in the selection of appropriate anticoagulants, reduction of hemodialysis time, and the amount of body fluid removed.

18.
Elife ; 92020 10 14.
Article in English | MEDLINE | ID: mdl-33052098

ABSTRACT

ATP is essential for all living cells. However, how dead cells lose ATP has not been well investigated. In this study, we developed new FRET biosensors for dual imaging of intracellular ATP level and caspase-3 activity in single apoptotic cultured human cells. We show that the cytosolic ATP level starts to decrease immediately after the activation of caspase-3, and this process is completed typically within 2 hr. The ATP decrease was facilitated by caspase-dependent cleavage of the plasma membrane channel pannexin-1, indicating that the intracellular decrease of the apoptotic cell is a 'programmed' process. Apoptotic cells deficient of pannexin-1 sustained the ability to produce ATP through glycolysis and to consume ATP, and did not stop wasting glucose much longer period than normal apoptotic cells. Thus, the pannexin-1 plays a role in arresting the metabolic activity of dead apoptotic cells, most likely through facilitating the loss of intracellular ATP.


Subject(s)
Adenosine Triphosphate/metabolism , Apoptosis/physiology , Connexins/genetics , Nerve Tissue Proteins/genetics , Caspase 3/metabolism , Connexins/metabolism , HeLa Cells , Humans , Nerve Tissue Proteins/metabolism , Single-Cell Analysis
19.
Sci Rep ; 10(1): 14886, 2020 09 10.
Article in English | MEDLINE | ID: mdl-32913258

ABSTRACT

The reverse transsulfuration pathway, which is composed of cystathionine ß-synthase (CBS) and cystathionine γ-lyase (CGL), plays a role to synthesize L-cysteine using L-serine and the sulfur atom in L-methionine. A plant-derived lactic acid bacterium Lactobacillus plantarum SN35N has been previously found to harbor the gene cluster encoding the CBS- and CGL-like enzymes. In addition, it has been demonstrated that the L. plantarum CBS can synthesize cystathionine from O-acetyl-L-serine and L-homocysteine. The aim of this study is to characterize the enzymatic functions of the L. plantarum CGL. We have found that the enzyme has the high γ-lyase activity toward cystathionine to generate L-cysteine, together with the ß-lyase activity toward L-cystine to generate L-cysteine persulfide. By the crystallographic analysis of the inactive CGL K194A mutant complexed with cystathionine, we have found the residues which recognize the distal amino and carboxyl groups of cystathionine or L-cystine. The PLP-bound substrates at the active site may take either the binding pose for the γ- or ß-elimination reaction, with the former being the major reaction in the case of cystathionine.


Subject(s)
Cystathionine gamma-Lyase/metabolism , Lactobacillus plantarum/enzymology , Catalysis , Crystallography, X-Ray , Cystathionine/metabolism , Cystathionine gamma-Lyase/chemistry , Homocysteine/metabolism , Serine/analogs & derivatives , Serine/metabolism , Substrate Specificity
20.
ACS Sens ; 4(12): 3333-3342, 2019 12 27.
Article in English | MEDLINE | ID: mdl-31845569

ABSTRACT

Branched-chain amino acids (BCAAs) are essential amino acids, controlling cellular metabolic processes as signaling molecules; therefore, utilization of intracellular BCAAs may be regulated by the availability of nutrients in the environment. However, spatial and temporal regulation of intracellular BCAA concentration in response to environmental conditions has been unclear due to the lack of suitable methods for measuring BCAA concentrations inside single living cells. Here, we developed a Förster resonance energy transfer (FRET)-based genetically encoded biosensor for BCAAs, termed optical biosensor for leucine-isoleucine-valine (OLIVe). The biosensor showed approximately 2-fold changes in FRET values corresponding to BCAA concentrations. Importantly, FRET signals from HeLa cells expressing OLIVe in the cytoplasm and nucleus correlated with bulk intracellular BCAA concentrations determined from populations of cells by a biochemical method, and were decreased by knockdown of L-type amino acid transporter 1 (LAT1), a transporter for BCAAs, indicating that OLIVe can reliably report intracellular BCAA concentrations inside single living cells. We also succeeded in imaging BCAA concentrations in the mitochondria using mitochondria-targeted OLIVe. Using the BCAA imaging technique, we found apparently correlated concentrations between the cytoplasm and the mitochondria. We also found that extracellular non-BCAA amino acids affected intracellular BCAA concentrations. Of these amino acids, extracellular glutamine markedly increased intracellular BCAA concentrations in a LAT1-dependent manner. Unexpectedly, extracellular pyruvate was also found to have significant positive effects on maintaining intracellular BCAA concentrations, suggesting that the cells have pyruvate-dependent systems to import BCAAs and/or to regulate BCAA metabolism.


Subject(s)
Amino Acids, Branched-Chain/analysis , Biosensing Techniques/methods , Carrier Proteins/metabolism , Escherichia coli Proteins/metabolism , Luminescent Proteins/metabolism , Recombinant Fusion Proteins/metabolism , Amino Acids, Branched-Chain/metabolism , Carrier Proteins/genetics , Carrier Proteins/radiation effects , Escherichia coli Proteins/genetics , Escherichia coli Proteins/radiation effects , Fluorescence Resonance Energy Transfer/methods , HeLa Cells , Humans , Light , Luminescent Proteins/genetics , Luminescent Proteins/radiation effects , Mitochondria/metabolism , Recombinant Fusion Proteins/genetics , Recombinant Fusion Proteins/radiation effects
SELECTION OF CITATIONS
SEARCH DETAIL