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Frontiers in Cellular Neuroscience 2024Intracellular Ca-signaling in astrocytes is instrumental for their brain "housekeeping" role and astroglial control of synaptic plasticity. An important source for...
Intracellular Ca-signaling in astrocytes is instrumental for their brain "housekeeping" role and astroglial control of synaptic plasticity. An important source for elevating the cytosolic Ca level in astrocytes is a release from endoplasmic reticulum which can be triggered via two fundamental pathways: IP3 receptors and calcium-induced calcium release (CICR) mediated by Ca-sensitive ryanodine receptors (RyRs). While the physiological role for glial IP3 became a focus of intensive research and debate, ryanodine receptors received much less attention. We explored the role for ryanodine receptors in the modulation of cytosolic Ca-signaling in the cortical and hippocampal astrocytes, astrocyte-neuron communication and astroglia modulation of synaptic plasticity. Our data show that RyR-mediated Ca-induced Ca-release from ER brings substantial contribution into signaling in the functional microdomains hippocampal and neocortical astrocytes. Furthermore, RyR-mediated CICR activated the release of ATP and glutamate from hippocampal and neocortical astrocytes which, in turn, elicited transient purinergic and tonic glutamatergic currents in the neighboring pyramidal neurons. The CICR-facilitated release of ATP and glutamate was inhibited after intracellular perfusion of astrocytes with ryanodine and BAPTA and in the transgenic dnSNARE mice with impaired astroglial exocytosis. We also found out that RyR-mediated amplification of astrocytic Ca-signaling enhanced the long-term synaptic potentiation in the hippocampus and neocortex of aged mice. Combined, our data demonstrate that ryanodine receptors are essential for astrocytic Ca-signaling and efficient astrocyte-neuron communications. The RyR-mediated CICR contributes to astrocytic control of synaptic plasticity and can underlie, at least partially, neuroprotective and cognitive effects of caffein.
PubMed: 38812795
DOI: 10.3389/fncel.2024.1382010 -
Life Sciences Aug 2024Dysregulated platelet aggregation is a fatal condition in many bacterial- and virus-induced diseases. However, classical antithrombotics cannot completely prevent...
AIMS
Dysregulated platelet aggregation is a fatal condition in many bacterial- and virus-induced diseases. However, classical antithrombotics cannot completely prevent immunothrombosis, due to the unaddressed mechanisms towards inflammation. Thus, targeting platelet hyperactivation together with inflammation might provide new treatment options in diseases, characterized by immunothrombosis, such as COVID-19 and sepsis. The aim of this study was to investigate the antiaggregatory effect and mode of action of 1.8-cineole, a monoterpene derived from the essential oil of eucalyptus leaves, known for its anti-inflammatory proprieties.
MAIN METHODS
Platelet activity was monitored by measuring the expression and release of platelet activation markers, i.e., P-selectin, CD63 and CCL5, as well as platelet aggregation, upon treatment with 1.8-cineole and stimulation with several classical stimuli and bacteria. A kinase activity assay was used to elucidate the mode of action, followed by a detailed analysis of the involvement of the adenylyl-cyclase (AC)-cyclic adenosine monophosphate (cAMP)-protein kinase A (PKA) pathway by Western blot and ELISA.
KEY FINDINGS
1.8-cineole prevented the expression and release of platelet activation markers, as well as platelet aggregation, upon induction of aggregation with classical stimuli and immunological agonists. Mechanistically, 1.8- cineole influences the activation of the AC-cAMP-PKA pathway, leading to higher cAMP levels and vasodilator-stimulated phosphoprotein (VASP) phosphorylation. Finally, blocking the adenosine A receptor reversed the antithrombotic effect of 1.8-cineole.
SIGNIFICANCE
Given the recognized anti-inflammatory attributes of 1.8-cineole, coupled with our findings, 1.8-cineole might emerge as a promising candidate for treating conditions marked by platelet activation and abnormal inflammation.
Topics: Eucalyptol; Receptor, Adenosine A2A; Platelet Activation; Platelet Aggregation; Humans; Cyclic AMP; Blood Platelets; Signal Transduction; P-Selectin; Cyclic AMP-Dependent Protein Kinases; Platelet Aggregation Inhibitors; Anti-Inflammatory Agents; COVID-19
PubMed: 38810792
DOI: 10.1016/j.lfs.2024.122746 -
Journal of the American Heart... Jun 2024ADP and ATP are importantly involved in vascular and thrombotic homeostasis, via multiple receptor pathways. Blockade of ADP P2Y receptors inhibits platelet aggregation... (Randomized Controlled Trial)
Randomized Controlled Trial
Safety, Tolerability, and Pharmacodynamics of AZD3366 (Optimized Human CD39L3 Apyrase) Alone and in Combination With Ticagrelor and Acetylsalicylic Acid: A Phase 1, Randomized, Placebo-Controlled Study.
BACKGROUND
ADP and ATP are importantly involved in vascular and thrombotic homeostasis, via multiple receptor pathways. Blockade of ADP P2Y receptors inhibits platelet aggregation and represents an effective cardiovascular disease prevention strategy. AZD3366 (APT102), a long-acting recombinant form of an optimized CD39L3 human apyrase, has effectively reduced ATP, ADP, and platelet aggregation and provided tissue protection in preclinical models, features that could be very beneficial in treating patients with cardiovascular disease.
METHODS AND RESULTS
We conducted this phase 1, first-in-human study of single ascending doses of intravenous AZD3366 or placebo, including doses added to dual antiplatelet therapy with ticagrelor and acetylsalicylic acid. The primary objective was safety and tolerability; secondary and exploratory objectives included pharmacokinetics, pharmacodynamics (measured as inhibition of platelet aggregation), adenosine diphosphatase (ADPase) activity, and ATP/ADP metabolism. In total, 104 participants were randomized. AZD3366 was generally well tolerated, with no major safety concerns observed. ADPase activity increased in a dose-dependent manner with a strong correlation to AZD3366 exposure. Inhibition of ADP-stimulated platelet aggregation was immediate, substantial, and durable. In addition, there was a prompt decrease in systemic ATP concentration and an increase in adenosine monophosphate concentrations, whereas ADP concentration appeared generally unaltered. At higher doses, there was a prolongation of capillary bleeding time without detectable changes in the ex vivo thromboelastometric parameters.
CONCLUSIONS
AZD3366 was well tolerated in healthy participants and demonstrated substantial and durable inhibition of platelet aggregation after single dosing. Higher doses prolonged capillary bleeding time without detectable changes in ex vivo thromboelastometric parameters.
REGISTRATION
URL: https://www.clinicaltrials.gov; Unique Identifier: NCT04588727.
Topics: Humans; Male; Ticagrelor; Female; Apyrase; Platelet Aggregation; Aspirin; Platelet Aggregation Inhibitors; Middle Aged; Adult; Double-Blind Method; Dual Anti-Platelet Therapy; Drug Therapy, Combination; Young Adult; Adenosine Diphosphate; Blood Platelets; Dose-Response Relationship, Drug; Treatment Outcome; Recombinant Proteins; Purinergic P2Y Receptor Antagonists
PubMed: 38804212
DOI: 10.1161/JAHA.123.033985 -
Clinical & Translational Immunology 2024Recent studies have identified expression of the non-functional P2X7 (nfP2X7) receptor on various malignant cells including ovarian cancer, but not on normal cells,...
OBJECTIVES
Recent studies have identified expression of the non-functional P2X7 (nfP2X7) receptor on various malignant cells including ovarian cancer, but not on normal cells, which makes it a promising tumour-associated antigen candidate for chimeric antigen receptor (CAR)-T-cell immunotherapies. In this study, we assessed the cytotoxic effects of nfP2X7-CAR-T cells on ovarian cancer using and models.
METHODS
We evaluated the effects of nfP2X7-CAR-T cells on ovarian cancer cell lines (SKOV-3, OVCAR3, OVCAR5), normal peritoneal cells (LP-9) and primary serous ovarian cancer cells derived from patient ascites using monolayer and 3D spheroid assays. We also evaluated the effects of nfP2X7-CAR-T cells on patient-derived tissue explants, which recapitulate an intact tumour microenvironment. In addition, we investigated the effect of nfP2X7-CAR-T cells using the OVCAR-3 xenograft model in NOD-scid IL2Rγnull (NSG) mice.
RESULTS
Our study found that nfP2X7-CAR-T cells were cytotoxic and significantly inhibited survival of OVCAR3, OVCAR5 and primary serous ovarian cancer cells compared with un-transduced CD3 T cells . However, no significant effects of nfP2X7-CAR-T cells were observed for SKOV3 or normal peritoneal cells (LP-9) cells with low P2X7 receptor expression. Treatment with nfP2X7-CAR-T cells increased apoptosis compared with un-transduced T cells in patient-derived explants and correlated with CD3 positivity. Treatment with nfP2X7-CAR-T cells significantly reduced OVCAR3 tumour burden in mice compared with un-transduced CD3 cells for 7-8 weeks.
CONCLUSION
This study demonstrates that nfP2X7-CAR-T cells have great potential to be developed as a novel immunotherapy for ovarian cancer.
PubMed: 38800555
DOI: 10.1002/cti2.1512 -
Pharmaceuticals (Basel, Switzerland) May 2024Gabapentin (GBP) was originally developed as a potential agonist for Gamma-Amino-Butyric-Acid (GABA) receptors, aiming to inhibit the activation of pain-signaling... (Review)
Review
Gabapentin (GBP) was originally developed as a potential agonist for Gamma-Amino-Butyric-Acid (GABA) receptors, aiming to inhibit the activation of pain-signaling neurons. Contrary to initial expectations, it does not bind to GABA receptors. Instead, it exhibits several distinct pharmacological activities, including: (1) binding to the alpha-2-delta protein subunit of voltage-gated calcium channels in the central nervous system, thereby blocking the excitatory influx of calcium; (2) reducing the expression and phosphorylation of CaMKII via modulation of ERK1/2 phosphorylation; (3) inhibiting glutamate release and interfering with the activation of NMDA receptors; (4) enhancing GABA synthesis; (5) increasing cell-surface expression of δGABA_A receptors, contributing to its antinociceptive, anticonvulsant, and anxiolytic-like effects. Additionally, GBP displays (6) inhibition of NF-kB activation and subsequent production of inflammatory cytokines, and (7) stimulation of the purinergic adenosine A1 receptor, which supports its anti-inflammatory and wound-healing properties. Initially approved for treating seizures and postherpetic neuralgia, GBP is now broadly used for various conditions, including psychiatric disorders, acute and chronic neuropathic pain, and sleep disturbances. Recently, as an eye drop formulation, it has also been explored as a therapeutic option for ocular surface discomfort in conditions such as dry eye, neurotrophic keratitis, corneal ulcers, and neuropathic ocular pain. This review aims to summarize the evidence supporting the molecular effects of GBP, with a special emphasis on its applications in ocular surface diseases.
PubMed: 38794193
DOI: 10.3390/ph17050623 -
Pharmaceuticals (Basel, Switzerland) May 2024P2X7 is an ATP-activated purinergic receptor implicated in pro-inflammatory responses. It is associated with the development of several diseases, including inflammatory...
P2X7 is an ATP-activated purinergic receptor implicated in pro-inflammatory responses. It is associated with the development of several diseases, including inflammatory and neurodegenerative conditions. Although several P2X7 receptor antagonists have recently been reported in the literature, none of them is approved for clinical use. However, the structure of the known antagonists can serve as a scaffold for discovering effective compounds in clinical therapy. This study aimed to propose an improved virtual screening methodology for the identification of novel potential P2X7 receptor antagonists from natural products through the combination of shape-based and docking approaches. First, a shape-based screening was performed based on the structure of JNJ-47965567, a P2X7 antagonist, using two natural product compound databases, MEGx (~5.8 × 10 compounds) and NATx (~32 × 10 compounds). Then, the compounds selected by the proposed shape-based model, with Shape-Tanimoto score values ranging between 0.624 and 0.799, were filtered for drug-like properties. Finally, the compounds that met the drug-like filter criteria were docked into the P2X7 allosteric binding site, using the docking programs and . The docking poses with the best score values were submitted to careful visual inspection of the P2X7 allosteric binding site. Based on our established visual inspection criteria, four compounds from the MEGx database and four from the NATx database were finally selected as potential P2X7 receptor antagonists. The selected compounds are structurally different from known P2X7 antagonists, have drug-like properties, and are predicted to interact with key P2X7 allosteric binding pocket residues, including F88, F92, F95, F103, M105, F108, Y295, Y298, and I310. Therefore, the combination of shape-based screening and docking approaches proposed in our study has proven useful in selecting potential novel P2X7 antagonist candidates from natural-product-derived compounds databases. This approach could also be useful for selecting potential inhibitors/antagonists of other receptors and/or biological targets.
PubMed: 38794162
DOI: 10.3390/ph17050592 -
International Journal of Molecular... May 2024Myocardial necrosis following the successful reperfusion of a coronary artery occluded by thrombus in a patient presenting with ST-elevation myocardial infarction... (Review)
Review
Initial Despair and Current Hope of Identifying a Clinically Useful Treatment of Myocardial Reperfusion Injury: Insights Derived from Studies of Platelet P2Y Antagonists and Interference with Inflammation and NLRP3 Assembly.
Myocardial necrosis following the successful reperfusion of a coronary artery occluded by thrombus in a patient presenting with ST-elevation myocardial infarction (STEMI) continues to be a serious problem, despite the multiple attempts to attenuate the necrosis with agents that have shown promise in pre-clinical investigations. Possible reasons include confounding clinical risk factors, the delayed application of protective agents, poorly designed pre-clinical investigations, the possible effects of routinely administered agents that might unknowingly already have protected the myocardium or that might have blocked protection, and the biological differences of the myocardium in humans and experimental animals. A better understanding of the pathobiology of myocardial infarction is needed to stem this reperfusion injury. P2Y receptor antagonists minimize platelet aggregation and are currently part of the standard treatment to prevent thrombus formation and propagation in STEMI protocols. Serendipitously, these P2Y antagonists also dramatically attenuate reperfusion injury in experimental animals and are presumed to provide a similar protection in STEMI patients. However, additional protective agents are needed to further diminish reperfusion injury. It is possible to achieve additive protection if the added intervention protects by a mechanism different from that of P2Y antagonists. Inflammation is now recognized to be a critical factor in the complex intracellular response to ischemia and reperfusion that leads to tissue necrosis. Interference with cardiomyocyte inflammasome assembly and activation has shown great promise in attenuating reperfusion injury in pre-clinical animal models. And the blockade of the executioner protease caspase-1, indeed, supplements the protection already seen after the administration of P2Y antagonists. Importantly, protective interventions must be applied in the first minutes of reperfusion, if protection is to be achieved. The promise of such a combination of protective strategies provides hope that the successful attenuation of reperfusion injury is attainable.
Topics: Myocardial Reperfusion Injury; Humans; Purinergic P2Y Receptor Antagonists; Animals; NLR Family, Pyrin Domain-Containing 3 Protein; Inflammation; Receptors, Purinergic P2Y12
PubMed: 38791515
DOI: 10.3390/ijms25105477 -
Cells May 2024Induction of the adenosine receptor A (AAR) expression in diabetic glomeruli correlates with an increased abundance of its endogenous ligand adenosine and the...
Pharmacological Blockade of the Adenosine A Receptor Is Protective of Proteinuria in Diabetic Rats, through Affecting Focal Adhesion Kinase Activation and the Adhesion Dynamics of Podocytes.
Induction of the adenosine receptor A (AAR) expression in diabetic glomeruli correlates with an increased abundance of its endogenous ligand adenosine and the progression of kidney dysfunction. Remarkably, AAR antagonism protects from proteinuria in experimental diabetic nephropathy. We found that AAR antagonism preserves the arrangement of podocytes on the glomerular filtration barrier, reduces diabetes-induced focal adhesion kinase (FAK) activation, and attenuates podocyte foot processes effacement. In spreading assays using human podocytes in vitro, adenosine enhanced the rate of cell body expansion on laminin-coated glass and promoted peripheral pY397-FAK subcellular distribution, while selective AAR antagonism impeded these effects and attenuated the migratory capability of podocytes. Increased phosphorylation of the Myosin2A light chain accompanied the effects of adenosine. Furthermore, when the AAR was stimulated, the cells expanded more broadly and more staining of pS19 myosin was detected which co-localized with actin cables, suggesting increased contractility potential in cells planted onto a matrix with a stiffness similar to of the glomerular basement membrane. We conclude that AAR is involved in adhesion dynamics and contractile actin bundle formation, leading to podocyte foot processes effacement. The antagonism of this receptor may be an alternative to the intervention of glomerular barrier deterioration and proteinuria in the diabetic kidney disease.
Topics: Podocytes; Animals; Humans; Proteinuria; Rats; Receptor, Adenosine A2B; Cell Adhesion; Focal Adhesion Protein-Tyrosine Kinases; Diabetes Mellitus, Experimental; Male; Diabetic Nephropathies; Adenosine A2 Receptor Antagonists; Adenosine; Cell Movement; Phosphorylation; Myosin Light Chains
PubMed: 38786068
DOI: 10.3390/cells13100846 -
Redox Biology Jul 2024Astrocytes are the major glial cells in the human brain and provide crucial metabolic and trophic support to neurons. The amyloid-β peptide (Aβ) alter the...
Astrocytes are the major glial cells in the human brain and provide crucial metabolic and trophic support to neurons. The amyloid-β peptide (Aβ) alter the morphological and functional properties of astrocytes and induce inflammation and calcium dysregulation, contributing to Alzheimer's disease (AD) pathology. Recent studies highlight the role of Toll-like receptor (TLR) 4/nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling in inflammation. Reactive oxygen species (ROS) generated due to Aβ, induce apoptosis in the brain cells worsening AD progression. Astrocytic cell surface receptors, such as purinergic receptors (P2Y1 and P2Y2), metabotropic glutamate receptor (mGLUR)5, α7 nicotinic acetylcholine receptor (α7nAChR), and N-methyl-d-aspartate receptors (NMDARs), have been suggested to interact with inositol trisphosphate receptor (IPR) on the endoplasmic reticulum (ER) to induce Ca movement from ER to cytoplasm, causing Ca dysregulation. We found that the citrus flavonoid nobiletin (NOB) protected primary astrocytes from Aβ42-induced cytotoxicity and inhibited TLR4/NF-κB signaling in Aβ42-induced primary rat astrocytes. NOB was found to regulate Aβ42-induced ROS levels through Keap1-Nrf2 pathway. The receptors P2Y1, P2Y2, mGLUR5, α7nAChR, and NMDARs induced intracellular Ca levels by activating IPR and NOB regulated them, thereby regulating intracellular Ca levels. Molecular docking analysis revealed a possible interaction between NOB and IPR in IPR regulation. Furthermore, RNA sequencing revealed various NOB-mediated biological signaling pathways, such as the AD-presenilin, AD-amyloid secretase, and Wnt signaling pathway, suggesting possible neuroprotective roles of NOB. To conclude, NOB is a promising therapeutic agent for AD and works by modulating AD pathology at various levels in Aβ42-induced primary rat astrocytes.
Topics: Astrocytes; Amyloid beta-Peptides; Animals; Inositol 1,4,5-Trisphosphate Receptors; Rats; Calcium; Flavones; Reactive Oxygen Species; Peptide Fragments; Neuroinflammatory Diseases; Humans; Signal Transduction; Toll-Like Receptor 4; Alzheimer Disease
PubMed: 38781730
DOI: 10.1016/j.redox.2024.103197 -
ACS Chemical Neuroscience Jun 2024Neuroinflammation plays an important role in Alzheimer's disease and primary tauopathies. The aim of the current study was to map [F]GSK1482160 for imaging of purinergic...
Neuroinflammation plays an important role in Alzheimer's disease and primary tauopathies. The aim of the current study was to map [F]GSK1482160 for imaging of purinergic P2X7R in Alzheimer's disease and primary tauopathy mouse models. Small animal PET was performed using [F]GSK1482160 in widely used mouse models of Alzheimer's disease (APP/PS1, 5×FAD, and 3×Tg), 4-repeat tauopathy (rTg4510) mice, and age-matched wild-type mice. Increased uptake of [F]GSK1482160 was observed in the brains of 7-month-old rTg4510 mice compared to wild-type mice and compared to 3-month-old rTg4510 mice. A positive correlation between hippocampal tau [F]APN-1607 and [F]GSK1482160 uptake was found in rTg4510 mice. No significant differences in the uptake of [F]GSK1482160 was observed for APP/PS1 mice, 5×FAD mice, or 3×Tg mice. Immunofluorescence staining further indicated the distribution of P2X7Rs in the brains of 7-month-old rTg4510 mice with accumulation of tau inclusion. These findings provide in vivo imaging evidence for an increased level of P2X7R in the brains of tauopathy mice.
Topics: Animals; Tauopathies; Receptors, Purinergic P2X7; Positron-Emission Tomography; Mice; Disease Models, Animal; Mice, Transgenic; Alzheimer Disease; Fluorine Radioisotopes; Brain; tau Proteins
PubMed: 38776461
DOI: 10.1021/acschemneuro.4c00067