Search results for "Phosphate"
showing 10 items of 1874 documents
Three-Dimensional Spheroid Primary Human Hepatocytes in Monoculture and Coculture with Nonparenchymal Cells
2018
Recent advances in the development of various culture platforms are promising for achieving more physiologically relevant in vitro hepatic models using primary human hepatocytes (PHHs). Previous studies have shown the value of PHHs three-dimensional (3D) spheroid models, cultured in low cell number (1330-2000 cells/3D spheroid), to study long-term liver function as well as pharmacological drug effects and toxicity. In this study, we report that only plateable PHHs aggregate and form compact 3D spheroids with a success rate of 79%, and 96% reproducibility. Out of 3D spheroid forming PHH lots, 65% were considered stable (<50% ATP decrease) over the subsequent 14 days of culture, with reproduc…
Structural Analysis of Phosphoserine Aminotransferase (Isoform 1) From Arabidopsis thaliana– the Enzyme Involved in the Phosphorylated Pathway of Ser…
2018
Phosphoserine aminotransferase (PSAT) is a pyridoxal 5'-phosphate (PLP)-dependent enzyme that catalyzes the conversion of 3-phosphohydroxypyruvate (3-PHP) to 3-phosphoserine (PSer) in an L-glutamate (Glu)-linked reversible transamination reaction. This process proceeds through a bimolecular ping-pong mechanism and in plants takes place in plastids. It is a part of the phosphorylated pathway of serine biosynthesis, one of three routes recognized in plant organisms that yield serine. In this three-step biotransformation, 3-phosphoglycerate (3-PGA) delivered from plastidial glycolysis and Calvin cycle is oxidized by 3-PGA dehydrogenase. Then, 3-PHP is subjected to transamination with Glu to yi…
ISWI ATP-dependent remodeling of nucleoplasmic ω-speckles in the brain of Drosophila melanogaster.
2017
Heterogeneous nuclear ribonucleoproteins (hnRNPs) belong to the RNA-binding proteins family. They are involved in processing heterogeneous nuclear RNAs (hnRNAs) into mature mRNAs. These proteins participate in every step of mRNA cycle, such as mRNA export, localization, translation, stability and alternative splicing. At least 14 major hnRNPs, which have structural and functional homologues in mammals, are expressed in Drosophila melanogaster. Until now, six of these hnRNPs are known to be nucleus-localized and associated with the long non-coding RNA (lncRNA) heat shock responsive ω (hsrω) in the omega speckle compartments (ω-speckles). The chromatin remodeler ISWI is the catalytic subunit …
Fabrication of a new physiological macroporous hybrid biomaterial/bioscaffold material based on polyphosphate and collagen by freeze-extraction
2020
We describe the fabrication of a new scaffold, an inorganic–organic hybrid biomaterial, consisting of the physiological polymers: the inorganic polymer polyphosphate (polyP), as well as the organic macromolecules collagen and chondroitin sulfate. The polyP polymer is composed of multiple phosphate orthophosphate units linked together by high-energy phosphoanhydride bonds. Chondroitin sulfate has been included due to its hydrogel-forming properties. In the presence of Ca2+ ions, the randomly coiled polyP reorganizes together with collagen and chondroitin sulfate to linear molecules which undergo hardening. This scaffold is deposited as amorphous Ca–polyP nanoparticles (size ≈20–40 nm large) …
The application of casein phosphopeptide and amorphous calcium phosphate with fluoride (CPP-ACPF) for restoring mineral loss after dental bleaching w…
2018
Abstract Objective To conduct an in vitro evaluation of the effect of casein-phosphopeptide and amorphous calcium phosphate with fluoride [CPP-ACPF] upon the calcium [Ca] and phosphorus [P] composition and morphology of dental enamel and dentin after the application of two bleaching agents: 37.5% hydrogen peroxide [HP]) and 35% carbamide peroxide [CP]. Materials and methods The crowns of 40 extracted human teeth were divided into four groups (n = 10 each). The crowns were sectioned along the cervical-incisal axis, and each half was embedded in acrylic resin, leaving a window 3 mm in diameter to explore the enamel or dentin (according to the study group involved). Groups 1a and 1b correspond…
Age-dependent control of collagen-dependent platelet responses by thrombospondin-1 : Comparative analysis of platelets from neonates, children, adole…
2021
Platelet function is developmentally regulated. Healthy neonates do not spontaneously bleed, but their platelets are hypo-reactive to several agonists. The mechanisms underlying immature platelet function in neonates are incompletely understood. This critical issue remains challenging for the establishment of age-specific reference ranges. In this study, we evaluated platelet reactivity of five pediatric age categories, ranging from healthy full-term neonates up to adolescents (11–18 years) in comparison to healthy adults (>
Enhancement of Wound Healing in Normal and Diabetic Mice by Topical Application of Amorphous Polyphosphate. Superior Effect of a Host⁻Guest Composite…
2017
The effect of polyphosphate (polyP) microparticles on wound healing was tested both in vitro and in a mice model in vivo. Two approaches were used: pure salts of polyphosphate, fabricated as amorphous microparticles (MPs, consisting of calcium and magnesium salts of polyP, “Ca–polyp-MPs” and “Mg–polyp-MPs”), and host–guest composite particles, prepared from amorphous collagen (host) and polyphosphate (guest), termed “col/polyp-MPs”. Animal experiments with polyP on healing of excisional wounds were performed using both normal mice and diabetic mice. After a healing period of 7 days “Ca–polyp-MP” significantly improved re-epithelialization in normal mice from 31% (control) to 72% (polyP micr…
Polyphosphate Reverses the Toxicity of the Quasi-Enzyme Bleomycin on Alveolar Endothelial Lung Cells In Vitro
2021
Simple Summary Bleomycin (BLM) is a medication introduced used to treat various types of cancer, including testicular cancer, ovarian cancer, and Hodgkin’s disease. Its most serious side effect is pulmonary fibrosis and impaired lung function. Using A549 human lung cells it is shown that, in parallel to an increased cell toxicity and DNA damage, BLM causes a marked enlargement of the cell nucleus. This effect is abolished by inorganic polyphosphate (polyP), if this physiological polymer is administered together with BLM. The detoxification of BLM is–most likely–caused by the upregulation of the gene encoding the BLM hydrolase which inactivates BLM in vitro and in vivo. This study contribute…
Activation of Mevalonate Pathway Via LKB1 is Essential for Stability of Treg Cells
2019
Summary: The function of regulatory T (Treg) cells depends on lipid oxidation. However, the molecular mechanism by which Treg cells maintain lipid metabolism after activation remains elusive. Liver kinase B1 (LKB1) acts as a coordinator by linking cellular metabolism to substrate AMP-activated protein kinase (AMPK). We show that deletion of LKB1 in Treg cells exhibited reduced suppressive activity and developed fatal autoimmune inflammation. Mechanistically, LKB1 induced activation of the mevalonate pathway by upregulating mevalonate genes, which was essential for Treg cell functional competency and stability by inducing Treg cell proliferation and suppressing interferon-gamma and interleuk…
Nitric Oxide System and Bronchial Epithelium: More Than a Barrier
2021
Airway epithelium forms a physical barrier that protects the lung from the entrance of inhaled allergens, irritants, or microorganisms. This epithelial structure is maintained by tight junctions, adherens junctions and desmosomes that prevent the diffusion of soluble mediators or proteins between apical and basolateral cell surfaces. This apical junctional complex also participates in several signaling pathways involved in gene expression, cell proliferation and cell differentiation. In addition, the airway epithelium can produce chemokines and cytokines that trigger the activation of the immune response. Disruption of this complex by some inflammatory, profibrotic, and carcinogens agents c…