Search Results (274)

The swallowing reflex is a highly coordinated process that is essential for safe bolus transit and airway protection. Although its neurophysiological framework has been extensively studied, the molecular mechanisms underlying reflex initiation remain incompletely understood, limiting targeted therapies for oropharyngeal dysphagia. Recent evidence implicates purinergic signaling as a key mediator of swallowing initiation, particularly through ATP release from taste buds and neuroendocrine cells in the hypopharyngeal and laryngeal mucosa. Experimental studies in mice demonstrate that water, acidic, and bitter chemical stimuli induce ATP release, activating purinergic receptors (P2X2, P2X3, heteromeric P2X2/P2X3, and P2Y1) on afferent sensory fibers. This receptor activation enhances input to the brainstem swallowing central pattern generator, initiating reflexive swallowing. Genetic ablation of purinergic receptor-expressing neurons or epithelial sentinel cells, as well as pharmacological antagonism of P2X or P2X3 receptors, markedly attenuates these responses. Furthermore, exogenous ATP or selective P2X3 agonists applied to swallowing-related mucosa evoke swallowing reflexes in an animal model, underscoring translational potential. While the precise upstream receptor mechanisms for water- and acid-induced ATP release, as well as species-specific differences, remain to be clarified, targeting purinergic pathways may represent a novel physiologically grounded therapeutic strategy for restoring swallowing function in patients with oropharyngeal dysphagia. Full article

Purinergic P2X7 receptors (P2X7Rs) may provide cardioprotection against ischemic heart disease. Cardiac angiogenesis is an endogenous adaptive response of hypoxic cardiomyocytes, mediated by vascular endothelial growth factor (VEGF) via hypoxia-inducible factor-1α (HIF-1α). The study aimed to determine whether P2X7Rs can regulate cardiac pro-angiogenic signaling in hypoxic H9c2 cardiomyocytes by modulating the angiogenic factor VEGF through HIF-1α genes. H9c2 rat cardiomyocytes were exposed to hypoxia alone or in combination with the P2X7R antagonist A740003. Subsequently, ATP levels and LDH activity were measured. The expression of P2X7R, HIF-1α, and VEGF was detected. Intracellular ATP level was significantly lower in hypoxia cardiomyocytes, whereas extracellular ATP, HIF-1α, and LDH levels were significantly higher in hypoxic cardiomyocytes. These effects were associated with increased P2X7R and VEGF gene expressions. Pretreatment with A740003 reversed HIF-1α and VEGF expressions in hypoxic cardiomyocytes. The findings suggest that P2X7Rs regulate pro-angiogenic signaling in hypoxic cardiomyocytes through the HIF-1α/VEGF pathway. Thus, the P2X7R-mediated HIF-1α/VEGF pathway may represent a novel approach to stimulating angiogenesis and preventing heart failure in ischemic heart disease. Full article

A large body of evidence suggests that flaxseed oil (FSO), one of the richest sources of essential omega-3 fatty acids, has neuroprotective properties. Purinergic signaling plays a crucial role in pathophysiological processes in the nervous system. There is a lack of evidence regarding the effects of FSO on the purinergic system under both physiological and neurotoxic conditions. Here we report the effects of dietary FSO consumption in a rat model of trimethyltin (TMT) intoxication. Exposure to TMT selectively induces hippocampal neuronal damage and glial reactivation associated with oxidative stress and neuroinflammation, causing severe behavioral impairments. When administered orally (1 mL/kg) before and during TMT intoxication (single dose 8 mg/kg, i.p.) to female Wistar rats, FSO effectively prevented the behavioral disturbances induced by TMT. FSO selectively increased CAT-mRNA level in both healthy and TMT-intoxicated animals, while preventing TMT-induced upregulation of Nrf2, NF-κB, and GPx1 without affecting SOD2 or Gsr-mRNA levels. FSO prevented microgliosis, microglial NTPDase1-eN upregulation, and the increase in purinergic receptors involved in microglial reactivity. Pretreatment with FSO in TMT-intoxicated rats maintained the activity and expression of NTPDase1 at control level, while the activity and expression of eN and ADA were increased. FSO upregulated eN, A₁R, A_2BR, A₃R, ADA, and NGF, while downregulating NTPDase1, A_2AR, and ENT1 in TMT-intoxicated rats. This suggests complex modulation of purinergic signaling, particularly the adenosine system. These findings may contribute to a better understanding of the effects of FSO, highlighting the impact of the dietary intake of this oil on the brain. Full article

Endometrial cancer is one of the most common malignancies of the female reproductive system, with incidence rising globally due to population ageing and life-style-related risk factors. Calcium (Ca²⁺) is a ubiquitous second messenger regulating diverse physiological processes, and its dysregulation has been increasingly implicated in carcinogenesis, including endometrial. Altered expression and function of Ca²⁺ channels, pumps, exchangers, and binding proteins disrupt the finely tuned balance of Ca²⁺ influx, efflux, and intracellular storage, leading to aberrant signalling that promotes tumour proliferation, migration, survival, and metastasis. This review summarises current knowledge on the molecular “Ca²⁺ toolkit” in the human uterus, highlighting the role of voltage-gated calcium channels (VGCCs), transient receptor potential (TRP) channels, store-operated calcium entry (SOCE) components, Na⁺/Ca²⁺ exchangers, purinergic receptors, P-type ATPases (SERCA, SPCA, PMCA), ryanodine (RyR) and inositol 1,4,5-trisphosphate (IP₃R) receptors, and mitochondrial Ca²⁺ uniporter (MCU) complexes in endometrial cancer progression. Multiple Ca²⁺-handling proteins, including CACNA1D, CACNA2D1, TRPV4, TRPV1, TRPM4, MCU, and RyR1, exhibit cancer-associated overexpression or functional changes, correlating with poor prognosis and aggressive disease features. Emerging evidence supports the therapeutic potential of targeting Ca²⁺ homeostasis using small-molecule inhibitors, ion channel modulators or gene-silencing strategies. These interventions may restore Ca²⁺ balance, induce apoptosis or autophagy, and suppress metastatic behaviour. While no clinical trials have yet explicitly focused on Ca²⁺ modulation in endometrial cancer, the diversity of dysregulated Ca²⁺ pathways offers a rich landscape for novel therapeutic strategies. Targeting key components of the Ca²⁺ signalling network holds promise for improving outcomes in endometrial cancer. Full article

Bladder dysfunction, particularly overactive bladder (OAB), is increasingly recognized as a clinical concern in patients with sickle cell disease (SCD), yet its pathophysiological mechanisms remain poorly understood. This study investigated the relationship between oxidative stress, inflammation, and bladder dysfunction in the Townes transgenic SCD mouse model. Cystometric analysis revealed that SCD mice exhibit an OAB phenotype, characterized by increased frequencies of voiding and non-voiding contractions and reduced bladder compliance. In vitro functional assays demonstrated detrusor hypocontractility in SCD mice, associated with a significant reduction in carbachol- and EFS-induced contractions and downregulation of muscarinic M3 receptor expression. Purinergic signaling and calcium-dependent contractility remained preserved. Molecular analyses showed increased mRNA expression of NOX-2 and IL-1β, and elevated protein levels of 3-nitrotyrosine and myeloperoxidase (MPO) activity, indicating redox imbalance and chronic inflammation in bladder tissue. Together, these changes suggest that oxidative and nitrosative stress, combined with inflammation, contribute to bladder remodeling and dysfunction in SCD. This is the first study to characterize bladder alterations in Townes SCD mice, establishing this model as a valuable tool for investigating lower urinary tract complications in SCD. Our findings provide mechanistic insight into the genitourinary manifestations of SCD and identify redox and inflammatory pathways as potential therapeutic targets for bladder dysfunction in affected individuals. Full article

Adenosine triphosphate (ATP) varies from nanomolar to millimolar levels across the physiological landscapes in which it serves as an energy carrier, phosphate donor, and purinergic signaling molecule. To measure these vastly different concentrations, genetically encoded sensors with different affinities are needed to match the particular ATP range and application. To this end, we mutagenized two key arginine residues in the ATP-binding domain of the ATeam family of sensors to explore how charge neutralization and charge reversal affect ATP affinity. As a result, we generated an extended family of affinity mutants with apparent dissociation constants ranging from sub-micromolar to millimolar. We then carried out live-cell imaging to demonstrate the utility of different affinity mutants in detecting mild versus extreme metabolic inhibition. Overall, these sensors add to the toolbox for understanding ATP dynamics in and around cells. Full article

Autosomal-dominant sleep-related hypermotor epilepsy (ADSHE) was the first distinct genetic epilepsy proven to be caused by mutation of the CHRNA4 gene, originally reported in 1994. In the past three decades, pathomechanisms of ADSHE associated with mutant nicotinic acetylcholine receptors (nAChRs) have been explored via various studies, including in vitro experiments and genetic rodent models. However, findings emphasize that functional abnormalities of ADSHE-mutant nAChRs alone cannot generate ictogenesis; rather, development of abnormalities in various other transmission systems induced by ADSHE-mutant nAChRs during the neurodevelopmental process before the ADSHE onset is involved in development of epileptogenesis/ictogenesis. Intra-thalamic GABAergic disinhibition induced by loss-of-function of S284L-mutant nAChRs (S286L-mutant nAChRs in rat ADSHE models) contributes to enhancing propagation of physiological ripple-burst high-frequency oscillation (HFO) and Erk signaling during sleep, leading to enhancement of the trafficking of pannexin1, connexin43, and P2X7 purinergic receptor to the astroglial plasma membrane. The combination of activation of physiological ripple-HFO and upregulation of astroglial hemichannels under the GABAergic disinhibition plays an important role in generation of epileptogenic fast-ripple-HFO during sleep. Therefore, loss-of-function of the S284L-mutation alone cannot drive ictogenesis but contributes to the development of epileptogenesis as an initial abnormality. Based on these recent findings using genetic rat ADSHE models, harboring the rat S286L-mutant Chrna4 corresponding to the human S284L-mutant CHRNA4, this report proposes hypothetical pathomechanisms of ADSHE. Full article

Adenosine triphosphate (ATP) is readily released into the extracellular space as an autocrine and paracrine purinergic signaling molecule. We originally reported a genetically encoded, fluorescent protein-based Förster Resonance Energy Transfer (FRET) biosensor that can detect micromolar levels of extracellular ATP. Through mutagenesis of the ATP binding site and optimization of cell-surface display, here we report the development of a second-generation biosensor called ECATS2 with greater than three-fold higher affinity for extracellular ATP. We found that the tether length between the FRET biosensor and the cell surface anchor is critical to optimization of its performance. Furthermore, we demonstrate that the improved sensor can detect extracellular ATP release upon hypoosmotic stress in cultured astrocytes. This new sensor contributes an improved tool for the ratiometric detection of extracellular ATP dynamics and purinergic signaling. Full article

The emergence of purinergic signaling has given ATP and other extracellular nucleotides a whole new perspective. This concept refers to the fact that extracellular nucleotides released by most cells act as signaling molecules via specific membrane receptors called purinergic receptors, thus regulating several cellular functions. Although purinergic signaling has been well studied in several physiological systems, recent work has shown that this signaling pathway is also essential in the immune system. In this review, we will discuss the complex role of purinergic signaling in the regulation of effector T cell functions, including migration, differentiation, and activation. We will also cover the role of P2 receptors in the development of autoimmune diseases. Understanding how P2 receptors regulate effector T cells will likely further our understanding of protective immunity and immune pathogenesis and may lead to new therapeutic approaches and agents in immune diseases Full article

The purinergic receptor P2RX4 contributes to the malignant behavior of breast and prostate cancers. It is upregulated in these malignancies and promotes tumor progression through mechanisms involving EMT, autophagy, and the release of pro-malignant lysosomal contents. P2RX4 also influences cellular signaling pathways by interacting with oncogenes and tumor suppressors. Certain genetic variants of P2RX4 are associated with an increased risk of developing these cancers. Hence, targeting P2RX4 represents a promising therapeutic approach, with potential strategies including antibody and CAR-T cell therapies and the development of small-molecule inhibitors. Further investigation is needed to fully elucidate the molecular mechanisms by which P2RX4 drives cancer progression and to translate these findings into effective and safe clinical therapies. Full article

Purinergic P2X7 receptors are involved in cellular processes such as inflammation, proliferation, and tissue remodeling, although their significance in human skin physiology remains poorly understood. In this study, we demonstrated strong P2X7 receptor immunoreactivity in the basal and granular layers of the epidermis. Cutaneous expression of P2X7 receptors was further confirmed at the level of specific mRNA and protein in cultured primary human keratinocytes and dermal fibroblasts. To reveal a possible role of these receptors in regulation of keratinocyte and fibroblast function, the cells were treated with a P2X7 agonist BzATP, or its selective antagonist A438079. Cell proliferation and viability were assessed using an immunofluorescence-based cell counter, and cell migration was evaluated by wound healing assay. P2X7 stimulation with BzATP significantly inhibited keratinocyte proliferation and migration, while P2X7 inhibition with A438079 significantly enhanced keratinocyte migration. In contrast, fibroblasts displayed minimal response to either treatment. These findings indicate that P2X7 regulates keratinocyte growth, and purinergic signaling may play a role in the skin. Our data also suggest that selective P2X7 inhibition may support re-epithelialization under conditions associated with impaired wound healing. Full article

Thyroid cancer (TC), the most prevalent endocrine neoplasia, has shown a progressive incidence, highlighting the need for new therapeutic approaches—especially for radioiodine-refractory cases, often associated with mutations in genes such as BRAF, RAS, and TP53. This review proposes a mechanistic model that highlights two interrelated characteristics of the tumor microenvironment (TME): redox imbalance and chronic inflammation, key elements in tumor progression and treatment resistance. Thus, natural phenolic compounds, such as curcumin, quercetin, resveratrol, and epigallocatechin gallate (EGCG), function not as simple antioxidants but as pleiotropic agents that reprogram the TME. A central mechanism of action for these compounds is the modulation of the purinergic axis (CD39/CD73/adenosine), a critical immune-metabolic checkpoint. By selectively inducing lethal oxidative stress in tumor cells, suppressing pro-survival inflammatory pathways—such as that mediated by nuclear factor kappa B (NF-κB)—and destabilizing the immunosuppressive shield conferred by adenosine, certain phytochemicals demonstrate the potential to restore immune surveillance and promote tumor apoptosis. In this context, a critical analysis of the evidence related to targeting purinergic signals becomes essential, since pharmacological reinforcement of this pathway, especially when combined with immunotherapies based on immune checkpoint blockade, emerges as a promising strategy for overcoming therapeutic resistance. Full article

Microglia, the brain’s resident innate immune cells, play a fundamental role in maintaining neural homeostasis and mediating responses to injury or infection. Upon activation, microglia undergo morphological and functional changes, including phenotypic switching between pro- and anti-inflammatory types and the release of different inflammatory mediators. These processes contribute to neuroprotection and the pathogenesis of various central nervous system (CNS) disorders. Mast cells, although sparsely located in the brain, exert a significant influence on neuroinflammation through their interactions with microglia. Through degranulation and secretion of different mediators, mast cells disrupt the blood–brain barrier and modulate microglial responses, including alteration of microglial phenotypes. Notably, mast cell-derived factors, such as histamine, interleukins, and tryptase, activate microglia through various pathways including protease-activated receptor 2 and purinergic receptors. These interactions amplify inflammatory cascades via various signaling pathways. Previous studies have revealed an exceedingly complex crosstalk between mast cells and microglia suggesting a bidirectional regulation of CNS immunity, implicating their cooperation in both neurodegenerative progression and repair mechanisms. Here, we review some of the diverse communication pathways involved in this complex interplay. Understanding this crosstalk may offer novel insights into the cellular dynamics of neuroinflammation and highlight potential therapeutic targets for a variety of CNS disorders. Full article

Pituitary neuroendocrine tumors (PitNETs) are the most common intracranial tumors. Evidence suggests that these types of tumors may have high recurrence rates. In this context, the purinergic system, oxidative stress, and inflammation are important signaling pathways involved in the cancer’s pathophysiology. This study aimed to evaluate the sociodemographic and diagnostic profiles, as well as assess the purinergic signaling, immunological, and redox profiles, of patients after PitNET resection. We collected sociodemographic data and the patients’ diagnostic profiles. We also collected blood samples to analyze glycemia, triglycerides, albumin, and ATP levels. The ectonucleotidase activity was determined in peripheral blood mononuclear cells (PBMCs). In addition, we evaluated their redox and immunological profiles. There was a prevalence of gonadotropic macroadenoma derived from PIT-1 cells. We found that patients included in the PitNET group had increased glycemia, serum ATP levels, and ATP hydrolysis in PBMCs. Analyzing their immunological profiles, we found that patients had increased levels of IL-6, IL-10, and TNF, while the IL-27 level was decreased. Regarding their redox profiles, PitNET patients had increased levels of ROS and protein carbonylation. Unexpectedly, patients also showed increased levels of non-protein thiols (NPSHs), total thiols (PSHs), and ascorbic acid. Thus, the dysregulation of purinergic signaling sustained chronic inflammation and oxidative imbalance in PitNET patients for a long time after surgical resection. These data suggest that patients with PitNETs require long-term accompanying to prevent cancer recurrence prognosis. The biomarkers highlighted in this study may be good tools to help the medical approaches. Full article

Next to adrenergic signalling, purinergic pathways mediated by extracellular adenine nucleotides have been described to shape thermogenic and metabolic functions in brown adipose tissue (BAT). Here we describe high expression of P2X5 that is activated by ATP in mature adipocytes of BAT and differentiated brown adipocytes in vitro. The levels of other P2X family members were much lower, or expression was restricted to tissue-resident macrophages or endothelial cells. Global and brown adipocyte-specific P2rx5 deficiency resulted in lower expression of the uncoupling protein 1 (UCP1). However, indirect calorimetry studies showed that P2X5 did not affect systemic energy expenditure. Of note, glucose tolerance was impaired under chow and obesogenic high-fat diet conditions, which can be explained by lower glucose disposal into BAT but not into other organs. In summary, these data indicate a modulatory role of P2X5 in systemic and BAT-specific glucose metabolism. Full article