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Arteriosclerosis, Thrombosis, and... Feb 2024Evolving evidence suggests that besides signaling pathways, platelet activation involves a complex interplay between metabolic pathways to support thrombus growth....
BACKGROUND
Evolving evidence suggests that besides signaling pathways, platelet activation involves a complex interplay between metabolic pathways to support thrombus growth. Selective targeting of metabolic checkpoints may inhibit platelet activation and provide a novel antiplatelet strategy. We, therefore, examined global metabolic changes that occur during the transition of human platelets from resting to an activated state to identify metabolites and associated pathways that contribute to platelet activation.
METHODS
We performed metabolic profiling of resting and convulxin-stimulated human platelet samples. The differential levels, pathway analysis, and PCA (principal component analysis) were performed using Metaboanalyst. Metascape was used for metabolite network construction.
RESULTS
Of the 401 metabolites identified, 202 metabolites were significantly upregulated, and 2 metabolites were downregulated in activated platelets. Of all the metabolites, lipids scored highly and constituted ≈50% of the identification. During activation, aerobic glycolysis supports energy demand and provides glycolytic intermediates required by metabolic pathways. Consistent with this, an important category of metabolites was carbohydrates, particularly the glycolysis intermediates that were significantly upregulated compared with resting platelets. We found that lysophospholipids such as 1-palmitoyl-GPA (glycero-3-phosphatidic acid), 1-stearoyl-GPS (glycero-3-phosphoserine), 1-palmitoyl-GPI (glycerophosphoinositol), 1-stearoyl-GPI, and 1-oleoyl-GPI were upregulated in activated platelets. We speculated that platelet activation could be linked to 1-carbon metabolism, a set of biochemical pathways that involve the transfer and use of 1-carbon units from amino acids, for cellular processes, including nucleotide and lysophospholipid synthesis. In alignment, based on pathway enrichment and network-based prioritization, the metabolites from amino acid metabolism, including serine, glutamate, and branched-chain amino acid pathway were upregulated in activated platelets, which might be supplemented by the high levels of glycolytic intermediates.
CONCLUSIONS
Metabolic analysis of resting and activated platelets revealed that glycolysis and 1-carbon metabolism are necessary to support platelet activation.
Topics: Humans; Blood Platelets; Glycolysis; Phosphorylation; Platelet Activation; Signal Transduction
PubMed: 37942614
DOI: 10.1161/ATVBAHA.123.319821 -
RSC Advances Sep 2023Chemodynamic therapy (CDT) has received more and more attention as an emerging therapeutic strategy, especially transition metals with Fenton or Fenton-like activity...
Chemodynamic therapy (CDT) has received more and more attention as an emerging therapeutic strategy, especially transition metals with Fenton or Fenton-like activity have good effects in CDT research, manganese dioxide nanosheets (MnO NSs) and their complexes have become one of the most favored nanomaterials in CDT of tumors. CDT is mainly based on the role of reactive oxygen species (ROS) in tumor treatment, which have clear chemical properties and produce clear chemical reactions. However, their mechanism of interaction with cells has not been fully elucidated. Here, we performed CDT on mouse breast cancer cells (4T1) based on MnO NSs, extracted the metabolites from the 4T1 cells during the treatment, and analyzed the differences in metabolites by using high-resolution liquid chromatography-mass spectrometry (LC-MS). Untargeted metabolomics studies were conducted using the relevant data. This study mainly explored the changes in MnO NSs on the metabolite profile of 4T1 cells and their potential impact on tumor therapy, in order to determine the mechanism of action of MnO NSs in the treatment of breast cancer. The results of the study showed the presence of 11 different metabolites in MnO NSs CDT for 4T1 tumor cells, including phosphoserine, sphingine, phosphocholine, and stearoylcarnitine. These findings provide a deeper understanding of breast cancer treatment, and are beneficial for the further research and clinical application of CDT.
PubMed: 37681048
DOI: 10.1039/d3ra03992g -
Synthetic and Systems Biotechnology Jun 2024Vitamin B plays a crucial role in cellular metabolism and stress response, making it an essential component for growth in all known organisms. However, achieving...
Vitamin B plays a crucial role in cellular metabolism and stress response, making it an essential component for growth in all known organisms. However, achieving efficient biosynthesis of vitamin B faces the challenge of maintaining a balanced distribution of metabolic flux between growth and production. In this study, our focus is on addressing this challenge through the engineering of phosphoserine aminotransferase (SerC) to resolve its redundancy and promiscuity. The enzyme SerC was semi-designed and screened based on sequences and predicted values, respectively. Mutants and heterologous proteins showing potential were then fine-tuned to optimize the production of vitamin B. The resulting strain enhances the production of vitamin B, indicating that different fluxes are distributed to the biosynthesis pathway of serine and vitamin B. This study presents a promising strategy to address the challenge posed by multifunctional enzymes, with significant implications for enhancing biochemical production through engineering processes.
PubMed: 38572022
DOI: 10.1016/j.synbio.2024.03.005 -
Frontiers in Pharmacology 2023Progesterone has been shown to have neuroprotective capabilities against a wide range of nervous system injuries, however there are negative clinical studies that have...
Progesterone has been shown to have neuroprotective capabilities against a wide range of nervous system injuries, however there are negative clinical studies that have failed to demonstrate positive effects of progesterone therapy. Specifically, we looked into whether progesterone receptors or its metabolizing enzymes, cytochrome P450c17 and 5α-reductase, are involved in the effects of progesterone on neuropathic pain after chronic constriction injury (CCI) of the sciatic nerve in mice. Intrathecal progesterone administration during the induction phase of chronic pain enhanced mechanical allodynia development and spinal glial fibrillary acidic protein (GFAP) expression, and this enhancement was inhibited by administration of ketoconazole, a P450c17 inhibitor, but not finasteride, a 5α-reductase inhibitor. Furthermore, phospho-serine levels of P450c17 in the spinal cord were elevated on day 1 after CCI operation, but not on day 17. In contrast, intrathecal progesterone administration during the maintenance phase of chronic pain decreased the acquired pain and elevated GFAP expression; this inhibition was restored by finasteride administration, but not by ketoconazole. The modification of mechanical allodynia brought on by progesterone in CCI mice was unaffected by the administration of mifepristone, a progesterone receptor antagonist. Collectively, these findings imply that progesterone suppresses spinal astrocyte activation via 5α-reductase activity during the maintenance phase of chronic pain and has an analgesic impact on the mechanical allodynia associated with the growing neuropathy. Progesterone, however, stimulates spinal astrocytes during the induction stage of peripheral neuropathy and boosts the allodynic impact caused by CCI through early spinal P450c17 activation.
PubMed: 38152690
DOI: 10.3389/fphar.2023.1253901 -
Bio-protocol Sep 2023
PubMed: 37818481
DOI: 10.21769/BioProtoc.4860 -
Endocrine Regulations Jan 2024Glucose and glutamine supply as well as serine synthesis and endoplasmic reticulum (ER) stress are important factors of glioblastoma growth. Previous studies showed...
Glucose and glutamine supply as well as serine synthesis and endoplasmic reticulum (ER) stress are important factors of glioblastoma growth. Previous studies showed that the knockdown of ERN1 (ER to nucleus signaling 1) suppressed glioblastoma cell proliferation and modified the sensitivity of numerous gene expressions to nutrient deprivations. The present study is aimed to investigate the impact of glucose and glutamine deprivations on the expression of serine synthesis genes in U87MG glioblastoma cells in relation to ERN1 knockdown with the intent to reveal the role of ERN1 signaling pathway on the ER stress-dependent regulation of these gene expressions. Clarification of the regulatory mechanisms of serine synthesis is a great significance for glioblastoma therapy. The control U87MG glioblastoma cells (transfected by empty vector) and ERN1 knockdown cells (transfected by dominant-negative ERN1) were exposed under glucose and glutamine deprivation conditions for 16 h. RNA was extracted from cells and reverse transcribed. The expression level of (phosphoglycerate dehydrogenase), (phosphoserine amino-transferase 1), (phosphoserine phosphatase), (activating transcription factor 4), and (serine hydroxymethyltransferase 1) genes was studied by real-time qPCR and normalized to ACTB. It was found that the expression level of genes responsible for serine synthesis such as , , , and transcription factor was up-regulated in U87MG glioblastoma cells under glucose and glutamine deprivations. Furthermore, inhibition of ERN1 significantly enhances the impact of glucose and especially glutamine deprivations on these gene expressions. At the same time, the expression of the gene, which is responsible for serine conversion to glycine, was down-regulated in both nutrient deprivation conditions with more significant changes in ERN1 knockdown glioblastoma cells. Taken together, the results of present study indicate that the expression of genes responsible for serine synthesis is sensitive to glucose and glutamine deprivations in gene-specific manner and that suppression of ERN1 signaling significantly modifies the impact of both glucose and glutamine deprivations on , , , , and gene expressions and reflects the ERN1-mediated genome reprograming introduced by nutrient deprivation condition.
Topics: Humans; Activating Transcription Factor 4; Brain Neoplasms; Cell Line, Tumor; Endoplasmic Reticulum Stress; Endoribonucleases; Gene Expression Regulation, Neoplastic; Gene Knockdown Techniques; Glioblastoma; Glucose; Glutamine; Glycine Hydroxymethyltransferase; Phosphoglycerate Dehydrogenase; Phosphoric Monoester Hydrolases; Protein Serine-Threonine Kinases; Serine; Signal Transduction; Transaminases
PubMed: 38656254
DOI: 10.2478/enr-2024-0010 -
ACS Omega Apr 2024The aim of this study is to explore the inhibition of nanocalcium oxalate monohydrate (nano-COM) crystal adhesion and aggregation on the HK-2 cell surface after the...
UNLABELLED
The aim of this study is to explore the inhibition of nanocalcium oxalate monohydrate (nano-COM) crystal adhesion and aggregation on the HK-2 cell surface after the protection of corn silk polysaccharides (CSPs) and the effect of carboxyl group (-COOH) content and polysaccharide concentration.
METHOD
HK-2 cells were damaged by 100 nm COM crystals to build an injury model. The cells were protected by CSPs with -COOH contents of 3.92% (CSP0) and 16.38% (CCSP3), respectively. The changes in the biochemical indexes of HK-2 cells and the difference in adhesion amount and aggregation degree of nano-COM on the cell surface before and after CSP protection were detected.
RESULTS
CSP0 and CCSP3 protection can obviously inhibit HK-2 cell damage caused by nano-COM crystals, restore cytoskeleton morphology, reduce intracellular ROS level, inhibit phosphoserine eversion, restore the polarity of the mitochondrial membrane potential, normalize the cell cycle process, and reduce the expression of adhesion molecules, OPN, Annexin A1, HSP90, HAS3, and CD44 on the cell surface. Finally, the adhesion and aggregation of nano-COM crystals on the cell surface were effectively inhibited. The carboxymethylated CSP3 exhibited a higher protective effect on cells than the original CSP0, and cell viability was further improved with the increase in polysaccharide concentration.
CONCLUSIONS
CSPs can protect HK-2 cells from calcium oxalate crystal damage and effectively reduce the adhesion and aggregation of nano-COM crystals on the cell surface, which is conducive to inhibiting the formation of calcium oxalate kidney stones.
PubMed: 38708219
DOI: 10.1021/acsomega.4c00110 -
Allergology International : Official... Jul 2023
Topics: Humans; Animals; Caseins; Phosphoserine; Phosphopeptides; Milk; Immunoglobulin E
PubMed: 36813678
DOI: 10.1016/j.alit.2023.02.001 -
The Journal of Biological Chemistry Mar 2024The cAMP/PKA and mitogen-activated protein kinase (MAPK) signaling cascade control many cellular processes and are highly regulated for optimal cellular responses upon...
The cAMP/PKA and mitogen-activated protein kinase (MAPK) signaling cascade control many cellular processes and are highly regulated for optimal cellular responses upon external stimuli. Phosphodiesterase 8A (PDE8A) is an important regulator that inhibits signaling via cAMP-dependent PKA by hydrolyzing intracellular cAMP pool. Conversely, PDE8A activates the MAPK pathway by protecting CRAF/Raf1 kinase from PKA-mediated inhibitory phosphorylation at Ser259 residue, a binding site of scaffold protein 14-3-3. It still remains enigmatic as to how the cross-talk involving PDE8A regulation influences cAMP/PKA and MAPK signaling pathways. Here, we report that PDE8A interacts with 14-3-3ζ in both yeast and mammalian system, and this interaction is enhanced upon the activation of PKA, which phosphorylates PDE8A's Ser359 residue. Biophysical characterization of phospho-Ser359 peptide with 14-3-3ζ protein further supports their interaction. Strikingly, 14-3-3ζ reduces the catalytic activity of PDE8A, which upregulates the cAMP/PKA pathway while the MAPK pathway is downregulated. Moreover, 14-3-3ζ in complex with PDE8A and cAMP-bound regulatory subunit of PKA, RIα, delays the deactivation of PKA signaling. Our results define 14-3-3ζ as a molecular switch that operates signaling between cAMP/PKA and MAPK by associating with PDE8A.
Topics: Humans; 14-3-3 Proteins; 3',5'-Cyclic-AMP Phosphodiesterases; Cyclic AMP-Dependent Protein Kinases; MAP Kinase Signaling System; Mitogen-Activated Protein Kinases; Phosphorylation; Phosphoserine; Cyclic AMP-Dependent Protein Kinase RIalpha Subunit
PubMed: 38325743
DOI: 10.1016/j.jbc.2024.105725 -
Nucleic Acids Research Apr 2024Protein-protein and protein-rRNA interactions at the interface between ribosomal proteins uS4 and uS5 are thought to maintain the accuracy of protein synthesis by...
An evolutionarily conserved phosphoserine-arginine salt bridge in the interface between ribosomal proteins uS4 and uS5 regulates translational accuracy in Saccharomyces cerevisiae.
Protein-protein and protein-rRNA interactions at the interface between ribosomal proteins uS4 and uS5 are thought to maintain the accuracy of protein synthesis by increasing selection of cognate aminoacyl-tRNAs. Selection involves a major conformational change-domain closure-that stabilizes aminoacyl-tRNA in the ribosomal acceptor (A) site. This has been thought a constitutive function of the ribosome ensuring consistent accuracy. Recently, the Saccharomyces cerevisiae Ctk1 cyclin-dependent kinase was demonstrated to ensure translational accuracy and Ser238 of uS5 proposed as its target. Surprisingly, Ser238 is outside the uS4-uS5 interface and no obvious mechanism has been proposed to explain its role. We show that the true target of Ctk1 regulation is another uS5 residue, Ser176, which lies in the interface opposite to Arg57 of uS4. Based on site specific mutagenesis, we propose that phospho-Ser176 forms a salt bridge with Arg57, which should increase selectivity by strengthening the interface. Genetic data show that Ctk1 regulates accuracy indirectly; the data suggest that the kinase Ypk2 directly phosphorylates Ser176. A second kinase pathway involving TORC1 and Pkc1 can inhibit this effect. The level of accuracy appears to depend on competitive action of these two pathways to regulate the level of Ser176 phosphorylation.
Topics: Saccharomyces cerevisiae Proteins; Saccharomyces cerevisiae; Ribosomal Proteins; Arginine; Protein Biosynthesis; Phosphoserine; Cyclin-Dependent Kinases; Phosphorylation; Evolution, Molecular; Protein Kinases
PubMed: 38340338
DOI: 10.1093/nar/gkae053