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Cell & Bioscience Apr 2024Ivermectin (IVM) is a commonly prescribed antiparasitic treatment with pharmacological effects on invertebrate glutamate ion channels resulting in paralysis and death of...
Ivermectin (IVM) is a commonly prescribed antiparasitic treatment with pharmacological effects on invertebrate glutamate ion channels resulting in paralysis and death of invertebrates. However, it can also act as a modulator of some vertebrate ion channels and has shown promise in facilitating L-DOPA treatment in preclinical models of Parkinson's disease. The pharmacological effects of IVM on dopamine terminal function were tested, focusing on the role of two of IVM's potential targets: purinergic P2X4 and nicotinic acetylcholine receptors. Ivermectin enhanced electrochemical detection of dorsal striatum dopamine release. Although striatal P2X4 receptors were observed, IVM effects on dopamine release were not blocked by P2X4 receptor inactivation. In contrast, IVM attenuated nicotine effects on dopamine release, and antagonizing nicotinic receptors prevented IVM effects on dopamine release. IVM also enhanced striatal cholinergic interneuron firing. L-DOPA enhances dopamine release by increasing vesicular content. L-DOPA and IVM co-application further enhanced release but resulted in a reduction in the ratio between high and low frequency stimulations, suggesting that IVM is enhancing release largely through changes in terminal excitability and not vesicular content. Thus, IVM is increasing striatal dopamine release through enhanced cholinergic activity on dopamine terminals.
PubMed: 38632622
DOI: 10.1186/s13578-024-01228-2 -
Nature Communications Apr 2024The adenosine A receptor (AAR), a key member of the G protein-coupled receptor family, is a promising therapeutic target for inflammatory and cancerous conditions. The...
The adenosine A receptor (AAR), a key member of the G protein-coupled receptor family, is a promising therapeutic target for inflammatory and cancerous conditions. The selective AAR agonists, CF101 and CF102, are clinically significant, yet their recognition mechanisms remained elusive. Here we report the cryogenic electron microscopy structures of the full-length human AAR bound to CF101 and CF102 with heterotrimeric G protein in complex at 3.3-3.2 Å resolution. These agonists reside in the orthosteric pocket, forming conserved interactions via their adenine moieties, while their 3-iodobenzyl groups exhibit distinct orientations. Functional assays reveal the critical role of extracellular loop 3 in AAR's ligand selectivity and receptor activation. Key mutations, including His, Ser, and Ser, in a unique sub-pocket of AAR, significantly impact receptor activation. Comparative analysis with the inactive AAR structure highlights a conserved receptor activation mechanism. Our findings provide comprehensive insights into the molecular recognition and signaling of AAR, paving the way for designing subtype-selective adenosine receptor ligands.
Topics: Humans; Receptor, Adenosine A3; Cryoelectron Microscopy; Signal Transduction
PubMed: 38627384
DOI: 10.1038/s41467-024-47207-6 -
Ecotoxicology and Environmental Safety May 2024Thioacetamide (TAA) within the liver generates hepatotoxic metabolites that can be induce hepatic fibrosis, similar to the clinical pathological features of chronic...
Thioacetamide (TAA) within the liver generates hepatotoxic metabolites that can be induce hepatic fibrosis, similar to the clinical pathological features of chronic human liver disease. The potential protective effect of Albiflorin (ALB), a monoterpenoid glycoside found in Paeonia lactiflora Pall, against hepatic fibrosis was investigated. The mouse hepatic fibrosis model was induced with an intraperitoneal injection of TAA. Hepatic stellate cells (HSCs) were subjected to treatment with transforming growth factor-beta (TGF-β), while lipopolysaccharide/adenosine triphosphate (LPS/ATP) was added to stimulate mouse peritoneal macrophages (MPMs), leading to the acquisition of conditioned medium. For TAA-treated mice, ALB reduced ALT, AST, HYP levels in serum or liver. The administration of ALB reduced histopathological abnormalities, and significantly regulated the expressions of nuclear receptor-related 1 protein (NURR1) and the P2X purinoceptor 7 receptor (P2×7r) in liver. ALB could suppress HSCs epithelial-mesenchymal transition (EMT), extracellular matrix (ECM) deposition, and pro-inflammatory factor level. ALB also remarkably up-regulated NURR1, inhibited P2×7r signaling pathway, and worked as working as C-DIM12, a NURR1 agonist. Moreover, deficiency of NURR1 in activated HSCs and Kupffer cells weakened the regulatory effect of ALB on P2×7r inhibition. NURR1-mediated inhibition of inflammatory contributed to the regulation of ALB ameliorates TAA-induced hepatic fibrosis, especially based on involving in the crosstalk of HSCs-macrophage. Therefore, ALB plays a significant part in the mitigation of TAA-induced hepatotoxicity this highlights the potential of ALB as a protective intervention for hepatic fibrosis.
Topics: Animals; Thioacetamide; Hepatic Stellate Cells; Mice; Liver Cirrhosis; Signal Transduction; Male; Nuclear Receptor Subfamily 4, Group A, Member 2; Bridged-Ring Compounds; Mice, Inbred C57BL; Inflammation; Epithelial-Mesenchymal Transition
PubMed: 38626607
DOI: 10.1016/j.ecoenv.2024.116334 -
Redox Biology Jun 2024Continuous remodeling of the heart can result in adverse events such as reduced myocardial function and heart failure. Available evidence indicates that ferroptosis is a...
Continuous remodeling of the heart can result in adverse events such as reduced myocardial function and heart failure. Available evidence indicates that ferroptosis is a key process in the emergence of cardiac disease. P2 family purinergic receptor P2X7 receptor (P2X7R) activation plays a crucial role in numerous aspects of cardiovascular disease. The aim of this study was to elucidate any potential interactions between P2X7R and ferroptosis in cardiac remodeling stimulated by angiotensin II (Ang II), and P2X7R knockout mice were utilized to explore the role of P2X7R and elucidate its underlying mechanism through molecular biological methods. Ferroptosis is involved in cardiac remodeling, and P2X7R deficiency significantly alleviates cardiac dysfunction, remodeling, and ferroptosis induced by Ang II. Mechanistically, Ang II interacts with P2X7R directly, and LYS-66 and MET-212 in the in the ATP binding pocket form a binding complex with Ang II. P2X7R blockade influences HuR-targeted GPX4 and HO-1 mRNA stability by affecting the shuttling of HuR from the nucleus to the cytoplasm and its expression. These results suggest that focusing on P2X7R could be a possible therapeutic approach for the management of hypertensive heart failure.
Topics: Receptors, Purinergic P2X7; Animals; Angiotensin II; Mice; Ferroptosis; Humans; Mice, Knockout; Ventricular Remodeling; Myocardium; Male; Protein Binding; Heart Failure
PubMed: 38626575
DOI: 10.1016/j.redox.2024.103154 -
European Journal of Medicinal Chemistry May 2024Imaging of the A adenosine receptor (AR) by positron emission tomography (PET) with 8-cyclopentyl-3-(3-[F]fluoropropyl)-1-propyl-xanthine ([F]CPFPX) has been widely used...
Imaging of the A adenosine receptor (AR) by positron emission tomography (PET) with 8-cyclopentyl-3-(3-[F]fluoropropyl)-1-propyl-xanthine ([F]CPFPX) has been widely used in preclinical and clinical studies. However, this radioligand suffers from rapid peripheral metabolism and subsequent accumulation of radiometabolites in the vascular compartment. In the present work, we prepared four derivatives of CPFPX by replacement of the cyclopentyl group with norbornane moieties. These derivatives were evaluated by competition binding studies, microsomal stability assays and LC-MS analysis of microsomal metabolites. In addition, the F-labeled isotopologue of 8-(1-norbornyl)-3-(3-fluoropropyl)-1-propylxanthine (1-NBX) as the most promising candidate was prepared by radiofluorination of the corresponding tosylate precursor and the resulting radioligand ([F]1-NBX) was evaluated by permeability assays with Caco-2 cells and in vitro autoradiography in rat brain slices. Our results demonstrate that 1-NBX exhibits significantly improved AR affinity and selectivity when compared to CPFPX and that it does not give rise to lipophilic metabolites expected to cross the blood-brain-barrier in microsomal assays. Furthermore, [F]1-NBX showed a high passive permeability (P = 6.9 ± 2.9 × 10 cm/s) and in vitro autoradiography with this radioligand resulted in a distribution pattern matching AR expression in the brain. Moreover, a low degree of non-specific binding (5%) was observed. Taken together, these findings identify [F]1-NBX as a promising candidate for further preclinical evaluation as potential PET tracer for AR imaging.
Topics: Receptor, Adenosine A1; Humans; Animals; Xanthines; Rats; Positron-Emission Tomography; Caco-2 Cells; Male; Molecular Structure; Structure-Activity Relationship; Radiopharmaceuticals; Dose-Response Relationship, Drug; Fluorine Radioisotopes
PubMed: 38615410
DOI: 10.1016/j.ejmech.2024.116380 -
Journal of Clinical Medicine Apr 2024: Etiopathogenesis and the symptomatology of ureteropelvic junction obstruction (UPJO) in the pediatric population has not yet been definitely clarified, suggesting a...
: Etiopathogenesis and the symptomatology of ureteropelvic junction obstruction (UPJO) in the pediatric population has not yet been definitely clarified, suggesting a multifactorial nature of the condition. The aim was to analyze the association between the number of Interstitial Cells of Cajal (ICCs), as well as PX receptors in ureteropelvic junction (UPJ) and the pain response in pediatric patients with hydronephrosis. 50 patients with congenital hydronephrosis underwent open or laparoscopic pyeloplasty at one of two departments of pediatric surgery and urology in Poland. Patients were divided into two groups according to the pain symptoms before surgery. A total of 50 samples of UPJ were obtained intraoperatively and underwent histopathological and immunohistochemical (IHC) analysis. Quantitative assessment of ICCs was based on the number of CD117(+) cells of adequate morphology in the subepithelial layer and the muscularis propria. Expression of PX receptors was evaluated as the intensity of IHC staining. Patients with hydronephrosis and accompanying pain were on average 60 months older (77 vs. 17 months) than children with asymptomatic hydronephrosis ( = 0.017). Symptomatic children revealed higher numbers of ICCs in both the subepithelial layer and in the lamina muscularis propria. In particular, symptomatic patients aged 2 years or more exhibited significantly higher numbers of ICCs in the subepithelial layer. Significant differences in the distribution of ICCs between the subepithelial layer and the lamina muscularis propria were observed in both groups. Expression of PX receptors was limited to the urothelium and the muscle layer and correlated between these structures. There was no relationship between pain response and the expression of PX receptors. ICCs and PX receptors may participate in the pathogenesis of UPJO and in the modulation of pain response to a dilatation of the pyelocaliceal system. Explanation of the role of ICCs and PX receptors in propagation of ureteral peristaltic wave and the modulation of pain stimuli requires further studies.
PubMed: 38610874
DOI: 10.3390/jcm13072109 -
Cells Mar 2024Extracellular vesicles (EVs) are secreted from many tumors, including glioblastoma multiforme (GBM), the most common and lethal brain tumor in adults, which shows high...
Extracellular vesicles (EVs) are secreted from many tumors, including glioblastoma multiforme (GBM), the most common and lethal brain tumor in adults, which shows high resistance to current therapies and poor patient prognosis. Given the high relevance of the information provided by cancer cell secretome, we performed a proteomic analysis of microvesicles (MVs) and exosomes (EXOs) released from GBM-derived stem cells (GSCs). The latter, obtained from the brain of GBM patients, expressed P2X7 receptors (P2X7Rs), which positively correlate with GBM growth and invasiveness. P2X7R stimulation of GSCs caused significant changes in the EV content, mostly ex novo inducing or upregulating the expression of proteins related to cytoskeleton reorganization, cell motility/spreading, energy supply, protection against oxidative stress, chromatin remodeling, and transcriptional regulation. Most of the induced/upregulated proteins have already been identified as GBM diagnostic/prognostic factors, while others have only been reported in peripheral tumors. Our findings indicate that P2X7R stimulation enhances the transport and, therefore, possible intercellular exchange of GBM aggressiveness-increasing proteins by GSC-derived EVs. Thus, P2X7Rs could be considered a new druggable target of human GBM, although these data need to be confirmed in larger experimental sets.
Topics: Humans; Cell Line, Tumor; Extracellular Vesicles; Glioblastoma; Neoplastic Stem Cells; Proteome; Proteomics; Receptors, Purinergic P2X7; Secretome
PubMed: 38607010
DOI: 10.3390/cells13070571 -
ENeuro Apr 2024A sublethal ischemic episode [termed preconditioning (PC)] protects neurons in the brain against a subsequent severe ischemic injury. This phenomenon is known as brain...
A sublethal ischemic episode [termed preconditioning (PC)] protects neurons in the brain against a subsequent severe ischemic injury. This phenomenon is known as brain ischemic tolerance and has received much attention from researchers because of its robust neuroprotective effects. We have previously reported that PC activates astrocytes and subsequently upregulates P2X7 receptors, thereby leading to ischemic tolerance. However, the downstream signals of P2X7 receptors that are responsible for PC-induced ischemic tolerance remain unknown. Here, we show that PC-induced P2X7 receptor-mediated lactate release from astrocytes has an indispensable role in this event. Using a transient focal cerebral ischemia model caused by middle cerebral artery occlusion, extracellular lactate levels during severe ischemia were significantly increased in mice who experienced PC; this increase was dependent on P2X7 receptors. In addition, the intracerebroventricular injection of lactate protected against cerebral ischemic injury. In in vitro experiments, although stimulation of astrocytes with the P2X7 receptor agonist BzATP had no effect on the protein levels of monocarboxylate transporter (MCT) 1 and MCT4 (which are responsible for lactate release from astrocytes), BzATP induced the plasma membrane translocation of these MCTs via their chaperone CD147. Importantly, CD147 was increased in activated astrocytes after PC, and CD147-blocking antibody abolished the PC-induced facilitation of astrocytic lactate release and ischemic tolerance. Taken together, our findings suggest that astrocytes induce ischemic tolerance via P2X7 receptor-mediated lactate release.
Topics: Animals; Astrocytes; Ischemic Preconditioning; Lactic Acid; Receptors, Purinergic P2X7; Male; Monocarboxylic Acid Transporters; Mice, Inbred C57BL; Basigin; Brain Ischemia; Symporters; Infarction, Middle Cerebral Artery; Disease Models, Animal; Muscle Proteins; Adenosine Triphosphate; Mice; Cells, Cultured; Brain; Mice, Knockout
PubMed: 38604775
DOI: 10.1523/ENEURO.0494-23.2024 -
Biomedicine & Pharmacotherapy =... May 2024This study aimed to determine whether trimethylamine N-oxide (TMAO) was involved in sympathetic activation in aging and the underlying mechanisms. Our hypothesis is TMAO...
This study aimed to determine whether trimethylamine N-oxide (TMAO) was involved in sympathetic activation in aging and the underlying mechanisms. Our hypothesis is TMAO reduces P2Y12 receptor (P2Y12R) and induces microglia-mediated inflammation in the paraventricular nucleus (PVN), then leading to sympathetic activation in aging. This study involved 18 young adults and 16 old adults. Aging rats were established by injecting D-galactose (D-gal, 200 mg/kg/d) subcutaneously for 12 weeks. TMAO (120 mg/kg/d) or 1% 3, 3-dimethyl-l-butanol (DMB) was administrated via drinking water for 12 weeks to investigate their effects on neuroinflammation and sympathetic activation in aging rats. Plasma TMAO, NE and IL-1β levels were higher in old adults than in young adults. In addition, standard deviation of all normal to normal intervals (SDNN) and standard deviation of the average of normal to normal intervals (SDANN) were lower in old adults and negatively correlated with TMAO, indicating sympathetic activation in old adults, which is associated with an increase in TMAO levels. Treatment of rats with D-gal showed increased senescence-associated protein levels and microglia-mediated inflammation, as well as decreased P2Y12R protein levels in PVN. Plasma TMAO, NE and IL-1β levels were increased, accompanied by enhanced renal sympathetic nerve activity (RSNA). While TMAO treatment exacerbated the above phenomenon, DMB mitigated it. These findings suggest that TMAO contributes to sympathetic hyperactivity in aging by downregulating P2Y12R in microglia and increasing inflammation in the PVN. These results may provide promising new target for the prevention and treatment of aging and aging-related diseases.
Topics: Animals; Rats; Aging; Down-Regulation; Galactose; Inflammation; Interleukin-1beta; Methylamines; Microglia; Norepinephrine; Paraventricular Hypothalamic Nucleus; Rats, Sprague-Dawley; Receptors, Purinergic P2Y12; Sympathetic Nervous System
PubMed: 38593701
DOI: 10.1016/j.biopha.2024.116549 -
Journal of Advanced Research Mar 2024Purinergic P2 receptors, which can be divided into ionotropic P2X receptors and metabotropic P2Y receptors, mediate cellular signal transduction of purine or pyrimidine... (Review)
Review
BACKGROUND
Purinergic P2 receptors, which can be divided into ionotropic P2X receptors and metabotropic P2Y receptors, mediate cellular signal transduction of purine or pyrimidine nucleoside triphosphates and diphosphate. Based on the wide expression of purinergic P2 receptors in tissues and organs, their significance in homeostatic maintenance, metabolism, nociceptive transmission, and other physiological processes is becoming increasingly evident, suggesting that targeting purinergic P2 receptors to regulate biological functions and signal transmission holds significant promise for disease treatment.
AIM OF REVIEW
This review highlights the detailed mechanisms by which purinergic P2 receptors engage in physiological and pathological progress, as well as providing prospective strategies for discovering clinical drug candidates.
KEY SCIENTIFIC CONCEPTS OF REVIEW
The purinergic P2 receptors regulate complex signaling and molecular mechanisms in nervous system, digestive system, immune system and as a result, controlling physical health states and disease progression. There has been a significant rise in research and development focused on purinergic P2 receptors, contributing to an increased number of drug candidates in clinical trials. A few influential pioneers have laid the foundation for advancements in the evaluation, development, and of novel purinergic P2 receptors modulators, including agonists, antagonists, pharmaceutical compositions and combination strategies, despite the different scaffolds of these drug candidates. These advancements hold great potential for improving therapeutic outcomes by specifically targeting purinergic P2 receptors.
PubMed: 38565403
DOI: 10.1016/j.jare.2024.03.027