Purinergic Signalling最新文献

We have previously reported that adenine at high doses interferes with the vasopressin signaling pathway, causes massive diuresis and volume depletion, and ultimately leads to renal failure. In the present study, we examined the effects of adenine on renal salt and water handling in a time course and dose-response study in rats housed in metabolic cages and fed control or adenine-containing diet at 1500, 2000, 2500 mg/kg and euthanized after 1, 3, and 7 weeks. Adenine at 2000 and 2500 mg/kg caused early and significant polyuria, polydipsia, and decreased urine osmolality in a dose-dependent manner without significantly affecting food intake, blood volume, blood electrolyte levels, or acid-base composition. The impaired water balance resulted from the downregulation of apical water channel AQP2 in the outer and inner medulla but not in the cortex. Adenine did not alter electrolytes (Na⁺, K⁺, Cl^-) excretion at these doses for up to 3 weeks. However, a slight but significant increase in salt excretion was observed in adenine-fed rats for 7 weeks, which correlates with a significant downregulation of NKCC2, mostly in rats fed 2500 mg/kg adenine. Adenine-fed rats exhibited a substantial resistance to vasopressin in response to water deprivation or vasopressin treatment. Lastly, 2500 mg/kg adenine prevented the development of hyponatremia in a rat experimental model of the syndrome of inappropriate secretion of antidiuretic hormone (SIADH). In conclusion, adenine acts as an aquaretic agent in the kidney at lower doses and during a short feeding period. It can be used as a vasopressin antagonist in conditions associated with hyponatremia.

Breast cancer (BC) is a multifactorial disease characterized by cell cycle disorder and immune evasion. Studies reveal that the purinergic system (PS) is a mediator of the immune system and actively participates in the inflammatory process in cancer. Also, there is growing debate about the role of oxidative stress (OS) markers and interleukins as predictors of BC progression and invasion. Thus, PS and OS markers, in addition to the expression of interleukins and quantification of extracellular ATP, were evaluated in 39 BC patients, before the beginning of surgical or pharmacological treatment, and in 35 control participants, matched by sex and age. The results show reduced ATP and ADP hydrolysis in platelets, apart from increased extracellular ATP in the BC group. Increased AMP hydrolysis was observed in BC patients' peripheral blood mononuclear cells (PBMCs). BC patients presented elevated oxidative parameters (MDA) and reduced antioxidant parameters (SOD and ascorbic acid), and reduction in interleukins TNF, IL-4, and IL-2. In PBMC from the BC group, the expression of P2X7 gene was significantly higher in relation to the expression of CD39 gene. Also, the expression of CD39 was 1.71 fold higher in tumor samples compared to PBMC from the BC group, and it was 0.11 fold lower in PBMC from the BC group compared to the controls. We conclude that ectoenzymes that hydrolyze ATP and ADP, mainly CD39, present reduced activity in the BC group, promoting an increase in extracellular ATP and culminating in a pro-inflammatory environment, favoring cancer progression. The increase in active oxidants and the reduction in antioxidants contributed to the progression of BC in patients. Finally, TNF and IL-4 demonstrated to be promising prognostic markers in BC patients.

This Journal Club article reviews a 2025 study by Qiu et al. that reports the development of a novel iodine-125 radioligand targeting the purinergic P2X7 receptor (P2X7R). The researchers created a small library of structurally modified P2X7R antagonists and identified compound 1c as a lead due to its high affinity and selectivity. Radiolabeling with iodine-125 produced [¹²⁵I]1c with high yield and purity. Binding studies confirmed its strong nanomolar affinity, supporting its use in radioligand screening and potential applications in imaging P2X7R in inflammatory and neurodegenerative diseases. The study demonstrates the value of radiolabeled probes in drug discovery and purinergic signaling research.

Periodontitis is a highly prevalent immunoinflammatory disease that compromises the supporting tissues of the teeth, especially the periodontal ligament and alveolar bone. During disease progression, inflammatory responses lead to the release of ATP, which interacts with purinergic receptors such as P2X7R, potentially influencing bone remodeling. Although P2X7R has been studied in bone cells, its specific role in periodontitis remains poorly characterized. This study aimed to evaluate the effects of P2X7R modulation on osteoblastic activity and experimental bone loss. In vitro, P2X7R expression was confirmed in OFCOL II osteoblastic cells. Receptor activation using BzATP significantly reduced cell viability, altered cell morphology, and decreased alkaline phosphatase (ALP) activity (p < 0.05). In vivo, periodontitis was induced in Wistar rats via ligature. Animals were allocated into four groups: (1) Naïve; (2) Periodontitis (saline-treated); (3) BzATP-treated (P2X7R agonist); and (4) BBG-treated (P2X7R antagonist). BzATP aggravated periodontal damage, with increased inflammation, loss of osteoblasts, and disorganization of periodontal ligament fibers. In contrast, BBG improved tissue architecture, reduced inflammatory infiltrate, and increased osteoblast numbers and ALP activity, possibly via the Wnt signaling pathway. These results suggest that P2X7R activation contributes to inflammation-driven bone loss, impairing osteoblast viability and function. Therefore, P2X7R inhibition may serve as a promising pharmacological strategy to preserve bone and periodontal integrity in the context of periodontitis.

The P2X7 receptor is a trimeric ion channel purinergic receptor. It plays a crucial part in the pathophysiology of cancers and a variety of inflammatory diseases and is widely expressed in different cell types. Leukemia represents a type of malignant clonal disorder that impacts the hematopoietic stem cells. Chemotherapy is one of the main treatment methods for leukemia, but there are also many side effects. In recent years, targeted therapy is a new treatment method. Research has shown that the progression and occurrence of leukemia is significantly related to the P2X7 receptor. The P2X7 receptor is also involved in the migration and invasion of leukemia cells. Furthermore, the polymorphism of the P2X7 receptor gene also takes on a significant function in the occurrence, development and clinical course of leukemia patients. The P2X7 receptor inhibitors have been found to work better in combination with existing therapeutics. Therefore, the P2X7 receptor may serve as a potential therapeutic target.

Over the past few years, transcriptomics has emerged as a pillar for modern scientific research, enabling the comprehensive profiling of gene expression. The availability of large-scale public datasets, such as NCBI Gene Expression Omnibus, International Cancer Genome Consortium, and The Cancer Genome Atlas, has significantly boosted many scientific discoveries. However, to analyze and interpret these vast datasets, sophisticated bioinformatic tools are often necessary. Phantasus is a user-friendly web application designed to streamline gene expression analysis. By integrating data loading, normalization, filtering, enrichment pathways analysis, and principal component analysis, Phantasus enables researchers to promptly investigate and evaluate complex gene expression patterns. This tool simplifies the identification of differentially expressed genes and the discovery of novel biological insights. Here, we demonstrate how Phantasus can be utilized for gene expression analysis in glioblastoma (GBM), the most common primary malignant brain tumour in adults. Specifically, we focus on the role of purinergic signaling, with particular emphasis on the P2RX7 mRNA coding for the P2X7 receptor (P2RX7). To illustrate our proposal, we analyzed the expression of genes related to purinergic signaling in GBM patients stratified by high and low levels of P2RX7 expression. By harnessing Phantasus, researchers can further explore and navigate the nuances of gene regulation and its impact on human health and diseases.

Purines are important mediators of intercellular communication in the enteric nervous system (ENS) that participate in physiological gut functions and disease. Purinergic transmission is prominent in mechanisms of crosstalk between enteric neurons and glia where enteric glia exhibit high responsiveness to adenosine diphosphate (ADP) through P2Y₁ receptors and neurons to adenosine triphosphate (ATP) through P2X₃ receptors. Despite functional data suggesting that enteric glia are the primary site of P2Y₁ expression in the ENS, gene sequencing suggests that P2Y₁ expression is more enriched in neurons than glia. The reason for the mismatch between genomic and functional data is unclear but could involve co-expression of inhibitory P2Y₁₂ receptors in neurons. We addressed this issue by studying the expression and function of P2Y₁ and P2Y₁₂ receptors in the mouse ENS using live immunolabeling and calcium imaging techniques. The data show that ADP drives activity among enteric glia and neurons in the myenteric plexus. Interestingly, inhibiting P2Y₁₂ activity increased neuron responses to ADP and overall spontaneous activity among enteric neurons and glia while decreasing the magnitude of glial responses to ADP. Investigating the location of the receptors involved revealed P2Y₁ receptor expression by both neurons and glia, while P2Y₁₂ receptor expression was minimal in the ENS. Instead, P2Y₁₂ expression was enriched in the surrounding muscularis macrophages. Macrophages positive for P2Y₁₂ overlapped with CD163 positive subsets that have known inhibitory influences over myenteric neurocircuits. Together, these data suggest that macrophage P2Y₁₂ pathways act to constrain activity in the ENS, which could have implications in mechanisms that contribute to enteric hyperexcitability following disease.

Adenosine is a key modulator in the pathophysiology of acute kidney injury (AKI), particularly through its influence on inflammatory pathways and renal hemodynamics. This nucleoside exerts its effects via four G protein-coupled receptors-A1, A2A, A2B, and A3-each displaying distinct roles during renal injury. The A1 receptor primarily protects renal tissue under ischemic conditions by reducing metabolic demand, while the A2A receptor promotes anti-inflammatory and vasodilatory effects, improving renal perfusion and attenuating leukocyte infiltration. The A2B receptor, upregulated under hypoxic or injury conditions, is involved in anti-inflammatory actions and vascular integrity, especially in renal tubular and endothelial cells. Conversely, activation of the A3 receptor is generally linked to adverse outcomes, including increased apoptosis and greater tissue damage. Therapeutic strategies targeting adenosine receptors are being actively explored: selective A1 and A2A agonists show potential for promoting renal recovery, while A3 antagonists helped counteract the harmful effects of A3 activation. The review also discusses advances from recent studies (2022-2024), including insights on COVID-19-associated AKI and the nuanced roles of A1 and A3 receptors in different pathological contexts. Additionally, the therapeutic promise of inhibiting adenosine-degrading enzymes, such as ADA and adenosine kinase (ADK), is highlighted. Novel mechanistic insights and recent literature are integrated, providing a comprehensive overview that expands upon previous reviews. Although adenosine receptor modulation holds significant promise as a therapeutic strategy for AKI, further clinical research is necessary to validate efficacy and safety in human populations.

Periodontal disease (PD) is characterized by the presence of a chronic inflammatory process, due to the accumulation of bacterial biofilm and the host's response to these pathogens, resulting in the destruction of the supporting tissues of dental structures. Studies have revealed that components of the purinergic system and inflammation are related to the development and progression of PD. The objective was to evaluate periodontal clinical parameters, modulation of the purinergic system and inflammation in patients with PD, compared to individuals without the disease. This is a cross-sectional study with 25 healthy individuals (CT group) and 57 individuals with PD, where blood and saliva collection and isolation of blood components were carried out. The results showed that there was a significant reduction in the hydrolysis of adenosine triphosphate (ATP; p < 0.0001), adenosine diphosphate (ADP; p < 0.05) and adenosine monophosphate (AMP; p < 0.01) in peripheral blood mononuclear cells (PBMCs) from individuals in the PD group compared to the CT group, indicating that individuals with PD showed reduced NTPDase 1 and Ecto-5'-nucleotidase activity. Adenosine deaminase activity in saliva (p < 0.0001) and serum p < 0.05) from individuals with PD were significantly higher compared to the CT group. Extracellular ATP and the serum concentration of C-Reactive Protein showed a statistically significant increase in the PD group ((p < 0.0001 and p < 0.001, respectively). Therefore, the enzymes of the purinergic system are present in the modulation of PD, leading individuals affected by the disease to a pro-inflammatory state, hindering the action of the immune system and increasing serum markers of inflammation.

The P2X7 receptor is an adenosine triphosphate (ATP)-gated ion channel expressed in different cell types of the brain. Polymorphisms in the P2RX7 gene have repeatedly been associated with psychiatric disorders including major depression. Depression is a stress-related disorder in which a dysregulation of the immune system has attracted increasing attention as a potential disease mechanism. The well-documented role of P2X7 in inflammatory conditions advocates its involvement in immune system dysregulation and depression genesis. However, understanding its exact role requires further research using appropriate animal models. Unfortunately, some of the most widely used P2X7 knockout mouse models are limited in their utility by the continuous expression of certain P2rx7 splice variants or even activation of de novo transcripts. To overcome this limitation, we generated a novel constitutive and complete P2X7 KO mouse line. These KO mice lack all known murine splice variants and protein expression resulting in a loss-of-function as confirmed by calcium imaging and by the inability of P2X7-deficient peritoneal macrophages to mount an appropriate interleukin (IL)-1β response. Comprehensive characterization using a battery of tests assessing locomotion, anxiety- and depression-related as well as social behaviour revealed differences in locomotor and exploratory behaviours. P2X7 KO mice showed slightly increased locomotor activity and reduced anxiety-related behaviour at baseline. Under conditions of chronic stress exposure, genotype-dependent differences largely dissolved while P2X7 deficiency promoted enhanced stress resilience with regard to social behaviour. Taken together, our findings add further evidence for an involvement of the P2X7 in shaping different behavioural responses and their modulation by stressful environments. This novel loss-of-function model will contribute to a better understanding of P2X7 in stress-associated behaviours in basic and translational neuropsychiatric research.