Purinergic Signalling最新文献

Endometriosis is a chronic gynecological condition characterized by endometrial tissue outside the uterine cavity. Recent research has focused on the relationship between the purinergic system and endometriosis. As a purinergic system component, extracellular adenosine triphosphate (ATP) has been involved as a crucial mediator of chronic pain associated with the disease, as well as P2X3 receptors, which play a key role in sensitization of nerve fibers and generation of nociceptive, neuropathic, and inflammatory pain. In addition, ectonucleotidases such as CD39 and CD73, which regulate ATP hydrolysis, have an altered expression in endometriotic lesions, contributing to extracellular ATP accumulation, intensifying inflammation and pain. Together, immune cells and their product are increased in endometriotic foci and promote the emergence of new lesions through their contribution to retrograde menstruation. Some studies have observed significant changes in mitochondrial respiration, notably decreased oxygen consumption in the affected endometrium. These various cellular processes that are mediated by ATP and adenosine in the uterine cavity and exert effects on immune defense will be herein reviewed in detail to investigate possible inhibitors, their activity, and potential exploration of the purinergic pathway as a therapeutic alternative.

The signaling mechanisms of nucleotides and nucleosides have been extensively studied over the past decades in various conditions affecting distinct organs and tissues. It is well-established that purinergic receptors are expressed in healthy tissues, with expression levels often increasing under pathological conditions. These receptors play crucial roles in numerous physiological and pathological processes, including inflammation, tissue repair, and cellular signaling. However, the purinergic context in the esophagus and its associated pathologies remains poorly understood, representing a significant gap in current knowledge. In this review, we compiled and analyzed the available data on the involvement of P2 purinergic receptors in esophageal diseases, such as gastroesophageal reflux disease and esophageal carcinoma. Specifically, we discuss the pharmacological modulation, functional characterization, and expression patterns of these receptors in various esophageal cell lines and immune tissue samples, under both healthy and pathological conditions. Understanding the mechanisms of action and signaling pathways involving P2 purinergic receptors in the esophagus can offer valuable insights into their biological roles and emphasize their potential as therapeutic targets for future clinical applications.

This study investigated the effects of physical exercise (PE) on the modulation of purinergic signaling and inflammatory profiles in sedentary women with type 2 diabetes mellitus (T2DM). Over 16 weeks, participants underwent a combined aerobic and resistance training program. The intervention resulted in reduced extracellular ATP levels and decreased activity of E-NTPDase and ADA enzymes, shifting the inflammatory balance toward an anti-inflammatory profile. A significant increase in anti-inflammatory cytokines (IL-10, IL-4) and a decrease in pro-inflammatory markers (TNF-α, IFN-γ, IL-6) were observed in the T2DM group. Correlations indicated that ATP hydrolysis was inversely related to anti-inflammatory cytokines, supporting the role of PE in modulating purinergic pathways. Additionally, improvements in glycemic control, systolic blood pressure, and functional capacity highlighted the systemic benefits of exercise. These findings emphasize the therapeutic potential of PE in managing T2DM by targeting inflammation and metabolic dysregulation through purinergic modulation. Further studies should explore these mechanisms to optimize exercise-based interventions.

Neuroblastoma is a pediatric tumor accounting for approximately 8% of childhood cancers and is associated with high mortality rates among children aged 1 to 5 years. Standard treatments often fall short, leading to recurrence and metastasis due to the development of chemoresistance. A promising approach to address this challenge involves targeting purinergic signaling pathways and drug repurposing. The combination of flubendazole in nanoformulation and vincristine exhibited synergistic effects in ACN cells, enhancing treatment efficacy. Vincristine combined with the P2X7 receptor antagonist Brilliant Blue-G showed antagonistic effects, and interactions between nanoFBZ and Brilliant Blue-G were dose-dependent. Furthermore, ACN cells exposed to 213 nM of vincristine weekly for three weeks resulted in vincristine-resistant cells with significantly higher resistance (IC₅₀ approximately 300 times greater) compared to parental cells. P2Y₂ receptor expression was augmented in vincristine-resistant cells, particularly after treatment with nanoFBZ and Brilliant Blue-G, while adenosine A1, A2B, and P2Y₆ receptor expression levels decreased. P2X7 receptor expression was also reduced in vincristine-resistant cells treated with nanoFBZ. P2X7 receptor agonism and P2Y₂ receptor blockade slightly elevated resistance. In conclusion, this study suggests that combining nanoFBZ with vincristine chemotherapy may offer a promising strategy for improving the treatment efficacy of neuroblastoma. The synergy between nanoFBZ and vincristine enhanced therapeutic outcomes, and P2X7 receptor antagonism further reduced neuroblastoma cell viability.

Purinergic signaling pathways play crucial roles in regulating hemostatic and inflammatory responses, both of which are impacted by scorpion envenomation. Scorpion venoms are complex mixtures of various toxins, such as peptides, enzymes, and nucleotides. Previous research showed that the action of scorpion toxins on the purinergic system stems from their effects on purinergic receptors. Additionally, a study identified a putative ectonucleotidase in scorpion venom. This study aimed to investigate the ability of Tityus confluens venom (10, 50, and 100 µg/mL) to metabolize adenine nucleotides and its potential effects on purinergic enzyme activity in rat platelets and lymphocytes. The effects of T. confluens venom on E-NTPDase (ATP and ADP hydrolysis), E-5'-NT (AMP hydrolysis), and E-ADA (ADO hydrolysis) activities were analyzed. The results revealed that crude venom from T. confluens exhibited ATP hydrolysis activity at all tested concentrations. In lymphocytes, ADP hydrolysis was inhibited by 100 µg/mL crude venom, whereas ADO hydrolysis was increased by all venom concentrations. In platelets, ATP hydrolysis was inhibited by 50 and 100 µg/mL crude venom, whereas AMP and ADO hydrolysis were inhibited by all concentrations. When considered collectively, the data suggested an elevation in extracellular ATP levels and a reduction in extracellular ADO. These findings are in alignment with clinical manifestations of scorpion envenomation characterized by a pro-inflammatory milieu. Furthermore, this study demonstrated the intrinsic ATPase activity of T. confluens venom and its ability to modulate E-NTPDase, E-5'-NT, and E-ADA activities in rat blood cells.

Hypochlorous acid (HOCl) is generated by neutrophils during the innate immune response. ATP is released from cells by various stimuli and during inflammation but whether ATP is released by and participates in the response to HOCl is unclear. This study investigated vasomotor effects of HOCl on the porcine coronary artery (PCA) and the involvement of ATP and purine receptors. HOCl at 100 μM induced rapid and transient endothelium-dependent relaxation followed by slow and sustained endothelium-independent relaxation. Transient endothelium-dependent relaxation was induced by 500 μM HOCl, followed by endothelium-dependent contraction, then slow endothelium-independent relaxation. 8-(p-sulphophenyl)theophylline (8-SPT), an adenosine/P1 receptor antagonist, blocked rapid relaxation and contraction to HOCl but an A_2A receptor antagonist, ZM 241385, and an A₁ receptor antagonist, DPCPX, had no effect. Suramin, a P2 receptor antagonist (and membrane channel inhibitor), blocked rapid relaxation (at 100 μM HOCl) and contraction to HOCl. Other antagonists for P2, P2X1, P2Y1 and P2X4 receptors (PPADS, reactive blue 2, NF449, MRS2179 and BX430) did not affect HOCl responses. Relaxation to exogenous ATP was inhibited by 8-SPT but not by suramin suggesting that suramin block of HOCl responses may involve inhibition of membrane channels and endogenous ATP release. Apyrase, which hydrolyzes nucleotides, abolished responses to HOCl, ATP and unexpectedly adenosine. Neither probenecid nor carbenoxelone (connexin and pannexin channel inhibitors) blocked responses to HOCl. Luminescent ATP assay showed that HOCl elicited ATP release from cultures of human coronary artery endothelial cells. These findings advance our understanding of inflammation by showing that HOCl evokes endothelium-dependent vasorelaxation and contraction in coronary arteries which may involve P1 receptors implicating endogenous adenosine, possibly generated from rapid metabolism of ATP released by HOCl.

Immunotherapies, such as immune checkpoint inhibitors (ICI), anti-cancer vaccines and adoptive T cell transfer, are promising treatments for cancer patients. However, ICI have not shown therapeutic benefit for most mismatch repair-proficient colorectal and pancreatic ductal adenocarcinoma tumors (PDAC), which are aggressive and deadly (Li et al. in Biomedicines 12:2175, 2024). Tumor metabolism can enhance immunological tolerance, but hinder immune cell function. In a recent publication in Nature Cancer, Scolaro et al. (Scolaro et al. in Nature Cancer 5:1206-1226, 2024) showed that cytidine deaminase (CDA) upregulation may play a crucial role in shaping the immunosuppressive landscape of human PDAC and other tumors. CDA targeting in pancreatic cancer cell lines led to reduced tumor growth, weight and total regression after treatment aimed at the programmed cell death protein 1 receptor (PD-1) immune checkpoint protein. CDA inhibition, both genetically and pharmacologically, overcame immunotherapy resistance in PDAC models. CDA targeting in PDAC cells altered the tumor microenvironment (TME), enabling T cells to respond to anti-PD-1. In mice with sgNT and sgCda tumors receiving anti-PD-1 treatment, they reduced the number of CD8⁺ T cells. CDA reduction in cancer cells makes tumors more sensitive to immunotherapy, presumably by overcoming immunosuppressive tumor-associated macrophages (TAMs) and forcing them to adopt an immunostimulatory phenotype. The study also found that cancer cells produce a TME rich in UDP (and UTP) by taking advantage of the CDA-mediated pyrimidine salvage pathway. This setting inhibits the recruitment and activation of CD8⁺ T cells by promoting the infiltration and immunosuppressive characteristics of P2Y₆ receptor-expressing TAMs.

Prostate cancer (PCa) preferentially metastasizes to bone, which remains incurable and contributes significantly to mortality and morbidity. The P2X4 receptor (P2X4R) is a receptor for ATP that is highly expressed in many cancer types including PCa and is positively associated with tumorigenesis. To understand the role of P2X4R in PCa biology, particularly in PCa bone metastasis, P2X4R (P2RX4) was knocked out in human PCa cell line PC3 cells using the CRISPR/Cas9 system. Cell proliferation, apoptosis, migration, and invasion were examined using CyQUANT, Cell Meter Caspase 3/7, scratch and transwell assays. Results showed that depleting P2X4R significantly reduced cell proliferation and invasion and increased apoptosis compared to PC3 wildtype (WT) controls in vitro. To test their metastatic potential in vivo, PC3 WT and knock-out (KO) cells were intracardiacally injected into male BALB/c immunocompromised mice. Twenty-five days post-injection, there were no detectable tumours and associated bone destruction in the tibias of mice injected with KO cells, whereas tibias of over 50% mice injected with WT cells were occupied by tumour cells, with significant bone destruction observed ex vivo using micro-CT. Furthermore, RNA-seq and bioinformatic analysis of P2X4R KO cells demonstrated links between P2X4R and PCa cell adhesion, and other key signalling such as Wnt signalling. These findings suggest that P2X4R is a potential therapeutic target for PCa metastasis, particularly bone metastasis.

Elevated interleukin-6 (IL-6) levels are linked to an increased risk of cardiovascular mortality in myocardial infarction (MI). Targeting IL-6 and its downstream signalling pathways represents a therapeutic strategy; however, its cellular sources and regulatory mechanisms of IL-6 remain incompletely understood. In this study, Alter and colleagues investigated the primary cell type that produces IL-6 in post-MI murine heart and the role of purinergic signalling in regulating IL-6 formation. Using cellular and mouse models, the authors identified cardiac fibroblasts as the predominant source of IL-6. Further analysis revealed that the IL-6 formation in cardiac fibroblasts is regulated by adenosine A_2B receptors. Of further importance, they elucidated that T cells highly express CD73, leading to significant adenosine formation, which in turn enhances IL-6 production via Gq activation in cardiac fibroblasts following MI. These findings reveal a dynamic interplay between immune cells and fibroblasts in shaping the post-MI inflammatory response. This study suggests the adenosine-A_2B receptor-IL6 axis as a potential therapeutic target to mitigate inflammation and improve cardiomyocytes salvage in MI.