Disruption of the Na+/K+-ATPase-purinergic P2X7 receptor complex in microglia promotes stress-induced anxiety.

Na+/K+-ATPase (NKA) plays an important role in the central nervous system. However, little is known about its function in the microglia. Here, we found that NKAα1 forms a complex with the purinergic P2X7 receptor (P2X7R), an adenosine 5'-triphosphate (ATP)-gated ion channel, under physiological conditions. Chronic stress or treatment with lipopolysaccharide plus ATP decreased the membrane expression of NKAα1 in microglia, facilitated P2X7R function, and promoted microglia inflammatory activation via activation of the NLRP3 inflammasome. Accordingly, global deletion or conditional deletion of NKAα1 in microglia under chronic stress-induced aggravated anxiety-like behavior and neuronal hyperexcitability. DR5-12D, a monoclonal antibody that stabilizes membrane NKAα1, improved stress-induced anxiety-like behavior and ameliorated neuronal hyperexcitability and neurogenesis deficits in the ventral hippocampus of mice. Our results reveal that NKAα1 limits microglia inflammation and may provide a target for the treatment of stress-related neuroinflammation and diseases.

Blockade of the Phagocytic Receptor MerTK on Tumor-Associated Macrophages Enhances P2X7R-Dependent STING Activation by Tumor-Derived cGAMP.

Clearance of apoptotic cells by macrophages prevents excessive inflammation and supports immune tolerance. Here, we examined the effect of blocking apoptotic cell clearance on anti-tumor immune response. We generated an antibody that selectively inhibited efferocytosis by phagocytic receptor MerTK. Blockade of MerTK resulted in accumulation of apoptotic cells within tumors and triggered a type I interferon response. Treatment of tumor-bearing mice with anti-MerTK antibody stimulated T cell activation and synergized with anti-PD-1 or anti-PD-L1 therapy. The anti-tumor effect induced by anti-MerTK treatment was lost in Stinggt/gt mice, but not in Cgas-/- mice. Abolishing cGAMP production in Cgas-/- tumor cells, depletion of extracellular ATP, or inactivation of the ATP-gated P2X7R channel also compromised the effects of MerTK blockade. Mechanistically, extracellular ATP acted via P2X7R to enhance the transport of extracellular cGAMP into macrophages and subsequent STING activation. Thus, MerTK blockade increases tumor immunogenicity and potentiates anti-tumor immunity, which has implications for cancer immunotherapy.

Context-dependent regulation of follicular helper T cell survival.

Follicular helper T (TFH) cells are a specialized subset of CD4+ T cells that support germinal centers in producing high-affinity antibody-secreting and memory B cells in mammals and birds. Therefore, mechanisms have evolved to control the life and death of TFH cells for balanced humoral immunity. Recent studies have collectively revealed at least two programmed cell death pathways, ferroptosis and pyroptosis, which govern TFH cell survival under diverse physiopathological conditions including immunization, infection, gut homeostasis, and autoimmunity. We review major recent advances in our understanding of the context-dependent regulation of TFH cell survival via cell death pathways that are closely connected with cellular metabolism. Such knowledge might be applied to inform new strategies aimed at modulating humoral immunity, potentially including enhancement of vaccine efficacies.

LncTCONS_00058568 is involved in the pathophysiologic processes mediated by P2X7R in the lower thoracic spinal cord after acute kidney injury.

Acute kidney injury (AKI), a prevalent clinical syndrome, involves the participation of the nervous system in neuroimmune regulation. However, the intricate molecular mechanism that governs renal function regulation by the central nervous system (CNS) is complex and remains incompletely understood. In the present study, we found that the upregulated expression of lncTCONS_00058568 in lower thoracic spinal cord significantly ameliorated AKI-induced renal tissue injury, kidney morphology, inflammation and apoptosis, and suppressed renal sympathetic nerve activity. Mechanistically, the purinergic ionotropic P2X7 receptor (P2X7R) was overexpressed in AKI rats, whereas lncTCONS_00058568 was able to suppress the upregulation of P2X7R. In addition, RNA sequencing data revealed differentially expressed genes associated with nervous system inflammatory responses after lncTCONS_00058568 was overexpressed in AKI rats. Finally, the overexpression of lncTCONS_00058568 inhibited the activation of PI3K/Akt and NF-κB signaling pathways in spinal cord. Taken together, the results from the present study show that lncTCONS_00058568 overexpression prevented renal injury probably by inhibiting sympathetic nerve activity mediated by P2X7R in the lower spinal cord subsequent to I/R-AKI.

Reduction of TRPV1 expression on neurons due to downregulation of P2X7R in neonatal rat dorsal root ganglion satellite glial cells under co-culture conditions.

BACKGROUND INFORMATION: The purinergic ligand-gated ion channel 7 receptor (P2X7R) is an ATP-gated ion channel that transmits extracellular signals and induces corresponding biological effects, transient receptor potential vanilloid type 1 (TRPV1) is a non-selective cation channel that maintains normal physiological functions; numerous studies showed that P2X7R and TRPV1 are associated with inflammatory reactions. RESULTS: The effect of P2X7R knockdown in satellite glial cells (SGCs) on neuronal TRPV1 expression under high glucose and high free fat (HGHF) environment was investigated. P2X7 short hairpin RNA (shRNA) was utilized to downregulate P2X7R in SGCs, and treated and untreated SGCs were co-cultured with neuronal cell lines. The expression levels of inflammatory factors and signaling pathways in SGCs and neurons were measured using Western blot analysis, RT-qPCR, immunofluorescence, and enzyme-linked immunosorbent assays. Results suggested that P2X7 shRNA reduced the expression levels of P2X7R protein and mRNA in SGCs surrounding DRG neurons and downregulated the release of tumor necrosis factor-alpha and interleukin-1 beta via the Ca2+/p38 MAPK/NF-κB pathway. Additionally, the downregulation of P2X7R might decrease TRPV1 expression in neurons via the Ca2+/PKC-ɛ/p38 MAPK pathway. CONCLUSIONS: Reducing P2X7R expression in SCGs in an HGHF environment could decrease neuronal TRPV1 expression via the Ca2+/PKC-ɛ/p38 MAPK pathway.

Increased concentrations of P2X7R in oligodendrocyte derived extracellular vesicles of Multiple sclerosis patients.

Activation of the purinergic receptor P2X7 (P2X7R) is believed to be deleterious in autoimmune diseases and it was hypothesized to play a role in the pathogenesis of MS. P2X7R is an ATP-gated non-selective cationic channel; its activation can be driven by high concentrations of ATP and leads to the generation of large, cytolytic conductance pores. P2X7R activation can also result in apoptosis as a consequence of the activation of the caspase cascade via P2X7R-dependent stimulation of the NLRP3 inflammasome. We measured P2X7R in oligodendrocyte derived extracellular vesicles (ODEVs) in MS patients and in healthy subjects. Sixty-eight MS patients (50 relapsing-remitting, RR-MS, 18 primary progressive, PP-MS) and 57 healthy controls (HC) were enrolled. ODEVs were enriched from serum by a double step immunoaffinity method using an anti OMGp (oligodendrocyte myelin glycoprotein) antibody. P2X7R concentration was measured in ODEVs lysates by ELISA. One-way Anova test showed that P2X7R in ODEVs is significantly higher in PP-MS (mean: 1742.89 pg/mL) compared both to RR-MS (mean: 1277.33 pg/mL) (p < 0.001) and HC (mean: 879.79 pg/mL) (p < 0.001). Comparison between RR-MS and HC was also statistically significant (p < 0.001). Pearson's correlations showed that P2RX7 in ODEVs was positively correlated with EDSS (p = 0.002, r = 0.38, 0.15-0.57 95% CI) and MSSS (p = 0.004, r = 0.34, 0.12-0.54 95% CI) scores, considering MS patients together (PP-MS + RR-MS) and with disease duration in PP-MS group (p = 0.02, r = 0.53, 0.09-0.80 95% CI). Results suggest that ODEVs-associated P2X7R levels could be a biomarker for MS.

The NLRP3 Inflammasome Gene Is Overexpressed in Hidradenitis Suppurativa Lesions: A Preliminary Study on the Role of Pyroptosis in Disease Pathogenesis.

Hidradenitis suppurativa (HS) is a debilitating inflammatory skin disorder, and its pathogenesis remains incompletely understood. This study aimed to investigate the role of the P2X7 receptor (P2X7R) and NLRP3 inflammasome in HS pathogenesis. RNA sequencing and real-time PCR were performed to assess the gene expression levels of P2X7R and NLRP3 in the skin biopsies of HS patients and healthy controls (HC). The results of our study revealed a significantly increased expression of the NLRP3 gene in both the lesional and perilesional skin of HS patients compared to healthy controls. Moreover, the mRNA levels of NLRP3 were significantly higher in lesional skin compared to non-lesional skin in HS patients, indicating the spread of inflammation to adjacent tissues. In contrast, no significant differences in P2X7R gene expression were observed between the three groups. These findings suggest the involvement of NLRP3 inflammasomes in HS pathogenesis, while P2X7R may not play a significant role in the disease. This research sheds light on the complex inflammatory pathways in HS, highlighting the potential of NLRP3 as a therapeutic target. Understanding the molecular mechanisms underlying HS is crucial for the development of targeted treatment modalities for this debilitating condition.

The impact of the P2X7 receptor on the tumor immune microenvironment and its effects on tumor progression.

Cancer is a significant global health concern, and finding effective methods to treat it has been a focus of scientific research. It has been discovered that the growth, invasion, and metastasis of tumors are closely related to the environment in which they exist, known as the tumor microenvironment (TME). The immune response interacting with the tumor occurring within the TME constitutes the tumor immune microenvironment, and the immune response can lead to anti-tumor and pro-tumor outcomes and has shown tremendous potential in immunotherapy. A channel called the P2X7 receptor (P2X7R) has been identified within the TME. It is an ion channel present in various immune cells and tumor cells, and its activation can lead to inflammation, immune responses, angiogenesis, immunogenic cell death, and promotion of tumor development. This article provides an overview of the structure, function, and pharmacological characteristics of P2X7R. We described the concept and components of tumor immune microenvironment and the influence immune components has on tumors. We also outlined the impact of P2X7R regulation and how it affects the development of tumors and summarized the effects of drugs targeting P2X7R on tumor progression, both past and current, assisting researchers in treating tumors using P2X7R as a target.

P2X7 receptor antagonists modulate experimental autoimmune neuritis via regulation of NLRP3 inflammasome activation and Th17 and Th1 cell differentiation.

BACKGROUND: Guillain-Barré syndrome (GBS), a post-infectious, immune-mediated, acute demyelinating disease of the peripheral nerves and nerve roots, represents the most prevalent and severe acute paralyzing neuropathy. Purinergic P2X7 receptors (P2X7R) play a crucial role in central nervous system inflammation. However, little is known about their role in the immune-inflammatory response within the peripheral nervous system. METHODS: Initially, we assessed the expression of purinergic P2X7R in the peripheral blood of patients with GBS using flow cytometry and qRT-PCR. Next, we explored the expression of P2 X7R in CD4+ T cells, CD8+ T cells, and macrophages within the sciatic nerves and spleens of rats using immunofluorescence labeling and flow cytometry. The P2X7R antagonist brilliant blue G (BBG) was employed to examine its therapeutic impact on rats with experimental autoimmune neuritis (EAN) induced by immunization with the P0180 - 199 peptide. We analyzed CD4+ T cell differentiation in splenic mononuclear cells using flow cytometry, assessed Th17 cell differentiation in the sciatic nerve through immunofluorescence staining, and examined the expression of pro-inflammatory cytokine mRNA using RT-PCR. Additionally, we performed protein blotting to assess the expression of P2X7R and NLRP3-related inflammatory proteins within the sciatic nerve. Lastly, we utilized flow cytometry and immunofluorescence labeling to examine the expression of NLRP3 on CD4+ T cells in rats with EAN. RESULTS: P2X7R expression was elevated not only in the peripheral blood of patients with GBS but also in rats with EAN. In rats with EAN, inhibiting P2X7R with BBG alleviated neurological symptoms, reduced demyelination, decreased inflammatory cell infiltration of the peripheral nerves, and improved nerve conduction. BBG also limited the production of pro-inflammatory molecules, down-regulated the expression of P2X7R and NLRP3, and suppressed the differentiation of Th1 and Th17 cells, thus protecting against EAN. These effects collectively contribute to modifying the inflammatory environment and enhancing outcomes in EAN rats. CONCLUSIONS: Suppression of P2X7R relieved EAN manifestation by regulating CD4+ T cell differentiation and NLRP3 inflammasome activation. This finding underscores the potential significance of P2X7R as a target for anti-inflammatory treatments, advancing research and management of GBS.

Human P2X7 receptor variants Gly150Arg and Arg276His polymorphisms have differential effects on risk association and cellular functions in pancreatic cancer.

BACKGROUND: The purinergic P2X7 receptor (P2X7R) plays an important role in the crosstalk between pancreatic stellate cells (PSCs) and cancer cells, thus promoting progression of pancreatic ductal adenocarcinoma (PDAC). Single nucleotide polymorphisms (SNPs) in the P2X7R have been reported for several cancers, but have not been explored in PDAC. MATERIALS AND METHODS: Blood samples from PDAC patients and controls were genotyped for 11 non-synonymous SNPs in P2X7R and a risk analysis was performed. Relevant P2X7R-SNP GFP variants were expressed in PSCs and cancer cells and their function was assayed in the following tests. Responses in Ca2+ were studied with Fura-2 and dye uptake with YO-PRO-1. Cell migration was monitored by fluorescence microscopy. Released cytokines were measured with MSD assay. RESULTS: Risk analysis showed that two SNPs 474G>A and 853G>A (rs28360447, rs7958316), that lead to the Gly150Arg and Arg276His variants, had a significant but opposite risk association with PDAC development, protecting against and predisposing to the disease, respectively. In vitro experiments performed on cancer cells and PSCs expressing the Gly150Arg variant showed reduced intracellular Ca2+ response, fluorescent dye uptake, and cell migration, while the Arg276His variant reduced dye uptake but displayed WT-like Ca2+ responses. As predicted, P2X7R was involved in cytokine release (IL-6, IL-1ß, IL-8, TNF-α), but the P2X7R inhibitors displayed varied effects. CONCLUSION: In conclusion, we provide evidence for the P2X7R SNPs association with PDAC and propose that they could be considered as potential biomarkers.

Alcohol and e-cigarette damage alveolar-epithelial barrier by activation of P2X7r and provoke brain endothelial injury via extracellular vesicles.

BACKGROUND: Use of nicotine containing products like electronic cigarettes (e-Cig) and alcohol are associated with mitochondrial membrane depolarization, resulting in the extracellular release of ATP, and mitochondrial DNA (mtDNA), mediating inflammatory responses. While nicotine effects on lungs is well-known, chronic alcohol (ETH) exposure also weakens lung immune responses and cause inflammation. Extracellular ATP (eATP) released by inflammatory/stressed cells stimulate purinergic P2X7 receptors (P2X7r) activation in adjacent cells. We hypothesized that injury caused by alcohol and e-Cig to pulmonary alveolar epithelial cells (hPAEpiC) promote the release of eATP, mtDNA and P2X7r in circulation. This induces a paracrine signaling communication either directly or via EVs to affect brain cells (human brain endothelial cells - hBMVEC). METHODS: We used a model of primary human pulmonary alveolar epithelial cells (hPAEpiC) and exposed the cells to 100 mM ethanol (ETH), 100 µM acetaldehyde (ALD), or e-Cig (1.75 µg/mL of 1.8% or 0% nicotine) conditioned media, and measured the mitochondrial efficiency using Agilent Seahorse machine. Gene expression was measured by Taqman RT-qPCR and digital PCR. hPAEpiC-EVs were extracted from culture supernatant and characterized by flow cytometric analysis. Calcium (Ca2+) and eATP levels were quantified using commercial kits. To study intercellular communication via paracrine signaling or by EVs, we stimulated hBMVECs with hPAEpiC cell culture medium conditioned with ETH, ALD or e-cig or hPAEpiC-EVs and measured Ca2+ levels. RESULTS: ETH, ALD, or e-Cig (1.8% nicotine) stimulation depleted the mitochondrial spare respiration capacity in hPAEpiC. We observed increased expression of P2X7r and TRPV1 genes (3-6-fold) and increased intracellular Ca2+ accumulation (20-30-fold increase) in hPAEpiC, resulting in greater expression of endoplasmic reticulum (ER) stress markers. hPAEpiC stimulated by ETH, ALD, and e-Cig conditioned media shed more EVs with larger particle sizes, carrying higher amounts of eATP and mtDNA. ETH, ALD and e-Cig (1.8% nicotine) exposure also increased the P2X7r shedding in media and via EVs. hPAEpiC-EVs carrying P2X7r and eATP cargo triggered paracrine signaling in human brain microvascular endothelial cells (BMVECs) and increased Ca2+ levels. P2X7r inhibition by A804598 compound normalized mitochondrial spare respiration, reduced ER stress and diminished EV release, thus protecting the BBB function. CONCLUSION: Abusive drugs like ETH and e-Cig promote mitochondrial and endoplasmic reticulum stress in hPAEpiC and disrupts the cell functions via P2X7 receptor signaling. EVs released by lung epithelial cells against ETH/e-cig insults, carry a cargo of secondary messengers that stimulate brain cells via paracrine signals.

Fetal bovine serum contains biologically available ATP.

ATP is a ubiquitous extracellular messenger released in a wide number of pathophysiological conditions. ATP is known to be present in minute amounts in the extracellular space in healthy tissues and in the blood, and to modulate a multiplicity of cell responses. Cell culture systems are widely used to explore purinergic signaling. We show here that currently used fetal bovine sera contain ATP in the 300-1300 pmol/L range. Serum ATP is associated with albumin as well as with microparticle/microvesicle fraction. Serum microparticles/microvesicles affect in vitro cell responses due to their content of miRNAs, growth factors, and other bioactive molecules. ATP is likely to be one of these bioactive factors found in a variable amount in sera of different commercial sources. ATP in serum supports ATP-dependent biochemical reactions such as the hexokinase-dependent phosphorylation of glucose to glucose 6-phosphate, and affects purinergic signaling. These findings show that cells growing in vitro in serum-supplemented media are exposed to varying levels of extracellular ATP, and thus to varying degrees of purinergic stimulation.

P2X7 receptor: a potential target for treating comorbid anxiety and depression.

In clinical practice, depression and anxiety frequently coexist, and they are both comorbid with somatic diseases. The P2X7R is an adenosine 5'-triphosphate (ATP)-gated non-selective cation channel that is widely expressed in immune-related cells. Under conditions of stress, chronic pain, and comorbid chronic physical illness, P2X7R activation in glial cells leads to neuroinflammation. This could contribute to the development of anxiety and depression-related emotional disturbances. Previous studies have shown that the P2X7 receptor (P2X7R) plays an important role in the pathogenesis of both anxiety and depression. Thus, the P2X7R may play a role in the comorbidity of anxiety and depression. Positron emission tomography can be used to assess the degree and location of neuroinflammation by monitoring functional and expression-related changes in P2X7R, which can facilitate clinical diagnoses and guide the treatment of patients with anxiety and depression. Moreover, single nucleotide polymorphisms (SNPs) in the P2X7R gene are associated with susceptibility to different types of psychiatric disorders. Thus, evaluating the SNPs of the P2X7R gene could enable personalized mood disorder diagnoses and treatments. If the P2X7R were set as a therapeutic target, selective P2X7R antagonists may modulate P2X7R function, thereby altering the balance of intra- and extra-cellular ATP. This could have therapeutic implications for treating anxiety and depression, as well as for pain management. According to in vitro and in vivo studies, the P2X7R plays an important role in anxiety and depression. In this review, we consider the potential of the P2X7R as a therapeutic target for comorbid anxiety and depression, and discuss the potential diagnostic and therapeutic value of this receptor.

Role of the P2X7 receptor in breast cancer progression.

Breast cancer is a common malignant tumor, whose incidence is increasing year by year, and it has become the malignant tumor with the highest incidence rate in women. Purine ligand-gated ion channel 7 receptor (P2X7R) is a cation channel receptor with Adenosine triphosphate ( ATP) as a ligand, which is widely distributed in cells and tissues, and is closely related to tumorigenesis and progression. P2X7R plays an important role in cancer by interacting with ATP. Studies have shown that P2X7R is up-regulated in breast cancer and can promote tumor invasion and metastasis by activating the protein kinase B (AKT) signaling pathway, promoting epithelial-mesenchymal transition (EMT), controlling the generation of extracellular vesicle (EV), and regulating the expression of the inflammatory protein cyclooxygenase 2 (COX-2). Furthermore, P2X7R was proven to play an essential role in the proliferation and apoptosis of breast cancer cells. Recently, inhibitors targeting P2X7R have been found to inhibit the progression of breast cancer. Natural P2X7R antagonists, such as rhodopsin, and the isoquinoline alkaloid berberine, have also been shown to be effective in inhibiting breast cancer progression. In this article, we review the research progress of P2X7R and breast cancer intending to provide new targets and directions for breast cancer treatment.

Partners in health and disease: pineal gland and purinergic signalling.

In mammal's pineal glands, ATP interacts with the high-affinity P2Y1 and the low-affinity P2X7 receptors. ATP released from sympathetic nerve terminals potentiates noradrenaline-induced serotonin N-acetyltransferase (Snat) transcription, N-acetylserotonin (NAS), and melatonin (MLT) synthesis. Circulating melatonin impairs the expression of adhesion molecules in endothelial cells, blocking the migration of leukocytes. Acute defence response induced by pathogen- and danger/damage-associated molecular patterns (PAMPs and DAMPs) triggers the NF-κB pathway in pinealocytes and blocks the transcription of Snat. Therefore, the darkness hormone is not released, and neutrophils and monocytes migrate to the lesion sites. ATP released in high amounts from apoptotic and death cells was considered a DAMP, and the blockage of P2X7 receptors was tested as a new class of drugs for treating brain damage. However, this is not a simple equation. High ATP injected in a lateral ventricle blocked MLT, but not NAS, synthesis as it impairs the transcription of acetyl serotonin N-methyltransferase. NAS is released in the plasma and the cerebral spinal fluid. NAS also blocks the rolling and adhesion of leukocytes to endothelial cells. Otherwise, it is metabolised specifically in each brain area to provide the requested concentration of MLT as a neuroprotector. As observed in physiological conditions, high extracellular ATP, different from the other DAMPs, reports the environmental light/dark cycle rhythm because NAS substitutes MLT as the nocturnal chemical indicator, the darkness hormone. Thus, blocking the P2X7R should not be considered a universal therapy for improving acute strokes, as MLT and ATP are partners in health and disease.

Functional role of P2X7 purinergic receptor in cancer and cancer-related pain.

Numerous studies have revealed that the ATP-gated ion channel purinergic 2X7 receptor (P2X7R) plays an important role in tumor progression and the pathogenesis of cancer pain. P2X7R requires activation by extracellular ATP to perform its regulatory role functions. During tumor development or cancer-induced pain, ATP is released from tumor cells or other cells in the tumor microenvironment (such as tumor-associated immune cells), which activates P2X7R, opens ion channels on the cell membrane, affects intracellular molecular metabolism, and regulates the activity of tumor cells. Furthermore, peripheral organs and receptors can be damaged during tumor progression, and P2X7R expression in nerve cells (such as microglia) is significantly upregulated, enhancing sensory afferent information, sensitizing the central nervous system, and inducing or exacerbating pain. These findings reveal that the ATP-P2X7R signaling axis plays a key regulatory role in the pathogenesis of tumors and cancer pain and also has a therapeutic role. Accordingly, in this study, we explored the role of P2X7R in tumors and cancer pain, discussed the pharmacological properties of inhibiting P2X7R activity (such as the use of antagonists) or blocking its expression in the treatment of tumor and cancer pain, and provided an important evidence for the treatment of both in the future.

P2X7 and P2Y1 receptors in DRG mediate electroacupuncture to inhibit peripheral sensitization in rats with IBS visceral pain.

Although multiple purinergic receptors mediate the analgesic effects of acupuncture, it remains unclear whether there is mutual interaction between purinergic receptors to jointly mediate the electroacupuncture inhibition of peripheral sensitization in visceral pain. Visceral hypersensitivity was induced by intracolonic 2,4,6-trinitrobenzene sulfonic acid (TNBS) in rat. The antinociception effect of electroacupuncture on visceral pain was evaluated by morphology, behaviors, neuroelectrophysiology and molecular biology techniques. After labeling the colon-related primary sensory neurons with neural retrograde tracer and employing neuropharmacology, neuroelectrophysiology, and molecular biotechnology, the mechanisms of P2X7R, P2Y1R, and P2X3R in colon-related dorsal root ganglion (DRG) neurons alleviating visceral hypersensitivity of irritable bowel syndrome (IBS) by electroacupuncture at Zusanli and Sanyinjiao acupoints.were elucidated from the perspective of peripheral sensitization. Electroacupuncture significantly inhibited TNBS-induced colonic hypersensitivity in rats with IBS, and Satellite Glial Cells (SGCs) in DRG were found to be involved in electroacupuncture-mediated regulation of the electrophysiological properties of neurons. P2X7R was found to play a pain-inducing role in IBS visceral hypersensitivity by affecting P2X3R, and electroacupuncture exerted an analgesic effect by inhibiting P2X7R activation. P2Y1R was found to play an analgesic role in the process of visceral pain, mediating electroacupuncture to relieve visceral hypersensitivity. P2Y1R relieved visceral pain by inhibiting P2X3R in neurons associated with nociception, with P2X7R identified as upstream of P2Y1R up-regulation by electroacupuncture. Our study suggests that the P2X7R → P2Y1R → P2X3R inhibitory pathway in DRG mediates the inhibition of peripheral sensitization by electroacupuncture in rats with IBS visceral hypersensitivity.

Electroacupuncture regulates the P2X7R-NLRP3 inflammatory cascade to relieve decreased sensation on ocular surface of type 2 diabetic rats with dry eye.

Dry eye (DE) is a prevalent ocular surface disease in patients with type 2 diabetes (T2DM). However, current medications are ineffective against decreased sensation on the ocular surface. While electroacupuncture (EA) effectively alleviates decreased sensation on ocular surface of DE in patients with T2DM, the neuroprotective mechanism remains unclear. This study explored the pathogenesis and therapeutic targets of T2DM-associated DE through bioinformatics analysis. It further investigated the underlying mechanism by which EA improves decreased sensation on the ocular surface of DE in rats with T2DM. Bioinformatic analysis was applied to annotate the potential pathogenesis of T2DM DE. T2DM and DE was induced in male rats. Following treatment with EA and fluorometholone, comprehensive metrics were assessed. Additionally, the expression patterns of key markers were studied. Key targets such as NLRP3, Caspase-1, and NOD-like receptor signaling may be involved in the pathogenesis of T2DM DE. EA treatment improved ocular measures. Furthermore, EA potently downregulated P2X7R, NLRP3, apoptosis-associated speck-like protein containing a CARD (ASC), and Caspase-1 expression within the trigeminal ganglion and spinal trigeminal nucleus caudalis. Targeted P2X7R antagonist (A-438079) and agonist (BzATP) employed as controls to decipher the biochemistry of the therapeutic effects of EA showed an anti-inflammatory effect with A-438079, while BzATP blocked the anti-inflammatory effect of EA. EA relieved DE symptoms and attenuated inflammatory damage to sensory nerve pathways in T2DM rats with DE. These findings suggest a crucial role of EA inhibition of the P2X7R-NLRP3 inflammatory cascade to provide these benefits.

Quercetin Mitigates Lysophosphatidylcholine (LPC)-Induced Neutrophil Extracellular Traps (NETs) Formation through Inhibiting the P2X7R/P38MAPK/NOX2 Pathway.

Neutrophil extracellular traps (NETs) are three-dimensional reticular structures that release chromatin and cellular contents extracellularly upon neutrophil activation. As a novel effector mechanism of neutrophils, NETs possess the capacity to amplify localized inflammation and have been demonstrated to contribute to the exacerbation of various inflammatory diseases, including cardiovascular diseases and tumors. It is suggested that lysophosphatidylcholine (LPC), as the primary active component of oxidized low-density lipoprotein, represents a significant risk factor for various inflammatory diseases, such as cardiovascular diseases and neurodegenerative diseases. However, the specific mechanism of NETs formation induced by LPC remains unclear. Quercetin has garnered considerable attention due to its anti-inflammatory properties, serving as a prevalent flavonoid in daily diet. However, little is currently known about the underlying mechanisms by which quercetin inhibits NETs formation and alleviates associated diseases. In our study, we utilized LPC-treated primary rat neutrophils to establish an in vitro model of NETs formation, which was subsequently subjected to treatment with a combination of quercetin or relevant inhibitors/activators. Compared to the control group, the markers of NETs and the expression of P2X7R/P38MAPK/NOX2 pathway-associated proteins were significantly increased in cells treated with LPC alone. Quercetin intervention decreased the LPC-induced upregulation of the P2X7R/P38MAPK/NOX2 pathway and effectively reduced the expression of NETs markers. The results obtained using a P2X7R antagonist/activator and P38MAPK inhibitor/activator support these findings. In summary, quercetin reversed the upregulation of the LPC-induced P2X7R/P38MAPK/NOX2 pathway, further mitigating NETs formation. Our study investigated the potential mechanism of LPC-induced NETs formation, elucidated the inhibitory effect of quercetin on NETs formation, and offered new insights into the anti-inflammatory properties of quercetin.

Regulation of the Nur77-P2X7r Signaling Pathway by Nodakenin: A Potential Protective Function against Alcoholic Liver Disease.

Alcoholic liver disease (ALD) is the main factor that induces liver-related death worldwide and represents a common chronic hepatopathy resulting from binge or chronic alcohol consumption. This work focused on revealing the role and molecular mechanism of nodakenin (NK) in ALD associated with hepatic inflammation and lipid metabolism through the regulation of Nur77-P2X7r signaling. In this study, an ALD model was constructed through chronic feeding of Lieber-DeCarli control solution with or without NK treatment. Ethanol (EtOH) or NK was administered to AML-12 cells, after which Nur77 was silenced. HepG2 cells were exposed to ethanol (EtOH) and subsequently treated with recombinant Nur77 (rNur77). Mouse peritoneal macrophages (MPMs) were treated with lipopolysaccharide/adenosine triphosphate (LPS/ATP) and NK, resulting in the generation of conditioned media. In vivo, histopathological alterations were markedly alleviated by NK, accompanied by reductions in serum triglyceride (TG), aspartate aminotransferase (AST), and alanine aminotransferase (ALT) levels and the modulation of Lipin-1, SREBP1, and Nur77 levels in comparison to the EtOH-exposed group (p < 0.001). Additionally, NK reduced the production of P2X7r and NLRP3. NK markedly upregulated Nur77, inhibited P2X7r and Lipin-1, and promoted the function of Cytosporone B, a Nur77 agonist (p < 0.001). Moreover, Nur77 deficiency weakened the regulatory effect of NK on P2X7r and Lipin-1 inhibition (p < 0.001). In NK-exposed MPMs, cleaved caspase-1 and mature IL-1ß expression decreased following LPS/ATP treatment (p < 0.001). NK also decreased inflammatory-factor production in primary hepatocytes stimulated with MPM supernatant. NK ameliorated ETOH-induced ALD through a reduction in inflammation and lipogenesis factors, which was likely related to Nur77 activation. Hence, NK is a potential therapeutic approach to ALD.