Microglia are involved in the inflammatory response and retinal ganglion cell damage in glaucoma. Here, we investigated how microglia proliferate and migrate in a mouse model of chronic ocular hypertension (COH). In COH retinas, the microglial proliferation that occurred was inhibited by the P2X7 receptor (P2X7R) blocker BBG or P2X7R knockout, but not by the P2X4R blocker 5-BDBD. Treatment of primary cultured microglia with BzATP, a P2X7R agonist, mimicked the effects of cell proliferation and migration in COH retinas through the intracellular MEK/ERK signaling pathway. Transwell migration assays showed that the P2X4R agonist CTP induced microglial migration, which was completely blocked by 5-BDBD. In vivo and in vitro experiments demonstrated that ATP, released from activated Müller cells through connexin43 hemichannels, acted on P2X7R to induce microglial proliferation, and acted on P2X4R/P2X7R (mainly P2X4R) to induce microglial migration. Our results suggest that inhibiting the interaction of Müller cells and microglia may attenuate microglial proliferation and migration in glaucoma.
Adenosine Triphosphate/pharmacology* ; Animals ; Cell Proliferation ; Glaucoma/metabolism* ; Mice ; Microglia/metabolism* ; Receptors, Purinergic P2X4/metabolism* ; Receptors, Purinergic P2X7/metabolism* ; Retinal Ganglion Cells/metabolism*

Irritable bowel syndrome is a gastrointestinal disorder of unknown etiology characterized by widespread, chronic abdominal pain associated with altered bowel movements. Increasing amounts of evidence indicate that injury and inflammation during the neonatal period have long-term effects on tissue structure and function in the adult that may predispose to gastrointestinal diseases. In this study we aimed to investigate how the epigenetic regulation of DNA demethylation of the p2x7r locus guided by the transcription factor GATA binding protein 1 (GATA1) in spinal astrocytes affects chronic visceral pain in adult rats with neonatal colonic inflammation (NCI). The spinal GATA1 targeting to DNA demethylation of p2x7r locus in these rats was assessed by assessing GATA1 function with luciferase assay, chromatin immunoprecipitation, patch clamp, and interference in vitro and in vivo. In addition, a decoy oligodeoxynucleotide was designed and applied to determine the influence of GATA1 on the DNA methylation of a p2x7r CpG island. We showed that NCI caused the induction of GATA1, Ten-eleven translocation 3 (TET3), and purinergic receptors (P2X7Rs) in astrocytes of the spinal dorsal horn, and demonstrated that inhibiting these molecules markedly increased the pain threshold, inhibited the activation of astrocytes, and decreased the spinal sEPSC frequency. NCI also markedly demethylated the p2x7r locus in a manner dependent on the enhancement of both a GATA1-TET3 physical interaction and GATA1 binding at the p2x7r promoter. Importantly, we showed that demethylation of the p2x7r locus (and the attendant increase in P2X7R expression) was reversed upon knockdown of GATA1 or TET3 expression, and demonstrated that a decoy oligodeoxynucleotide that selectively blocked the GATA1 binding site increased the methylation of a CpG island in the p2x7r promoter. These results demonstrate that chronic visceral pain is mediated synergistically by GATA1 and TET3 via a DNA-demethylation mechanism that controls p2x7r transcription in spinal dorsal horn astrocytes, and provide a potential therapeutic strategy by targeting GATA1 and p2x7r locus binding.
Animals ; Astrocytes/metabolism* ; DNA Demethylation ; Epigenesis, Genetic ; GATA1 Transcription Factor/metabolism* ; Inflammation/metabolism* ; Oligodeoxyribonucleotides/metabolism* ; Rats ; Rats, Sprague-Dawley ; Receptors, Purinergic P2X7/metabolism* ; Visceral Pain/metabolism*

OBJECTIVE: To explore the role of P2X7 receptor (P2X7R) in migration and invasion of mouse Lewis lung cancer (LLC) cells and examine the tumorigenic ability of LLC cells in P2X7R-knockout mice. METHODS: RT-PCR was used to examine P2X7R mRNA expression in LLC cells. LLC cells were treated with ATP (as a P2X7R agonist) or 2'- 3'- O- (4-benzoyl- benzoyl)-ATP (BzATP) (a P2X7R agonist) with or without pretreatment with P2X7R antagonist oxATP or A438079. The changes in migration and invasive abilities of the cells were evaluated using wound healing assay and Transwell assay; Western blotting was performed to determine the activation level of the key proteins in the AKT signaling pathway. The effects of BzATP, A438079, and LY294002 (a inhibitor of the PI3K/AKT pathway) on migration and invasion of LLC cells were also examined. In wild-type (WT) and P2X7R knockout (P2X7^-/-) C57BL/6 mice, the growth of subcutaneous LLC cell xenografts were observed by measuring tumor volume and weight. RESULTS: P2X7R expression was detected in LLC cells. Treatment with P2X7R agonist significantly enhanced migration and invasion abilities of LLC cells, and this effect was inhibited by application of P2X7R antagonists (P < 0.001). Western blotting showed that BzATP treatment of LLC cells significantly increased the expression level of p-AKT protein, which was obviously lowered by treatment with P2X7R antagonist (P < 0.01). P2X7R antagonist strongly inhibited BzATP-induced enhancement of LLC cell migration and invasion (P < 0.001). In the tumor- bearing mice, the tumor volume and weight were significantly lower in P2X7^-/- mice than in WT mice (P < 0.05). CONCLUSION P2X7R promotes migration and invasion of LLC cells by activating the AKT signaling pathway, and LLC cells show lowered tumorigenic capacity in P2X7^-/- mice.
Humans ; Mice ; Animals ; Receptors, Purinergic P2X7 ; Proto-Oncogene Proteins c-akt/metabolism* ; Phosphatidylinositol 3-Kinases/metabolism* ; Mice, Inbred C57BL ; Signal Transduction ; Adenosine Triphosphate/metabolism* ; Lung Neoplasms

OBJECTIVE: To investigate the correlation of receptor gene (P2X7, VDR and SLC19A1) polymorphisms with risk suffering from acute leukemia (AL) in Fujian area. METHODS: Ninety-three cases of newly diagnosed AL as AL group and 90 persons not suffered from hematologic and other tumors as control group were selected and used for comparative analysis of receptor gene polymorphisms and risk suffering from AL between case and control groups. The bone marrow and peripheral blood were collected, from which the DNA was extracted. The PCR-RFLP was used to detect 8 SNP sites (P2X7: rs208294, rs2230911, rs3751143; VDR: rs2228570, rs7975232; SLC194A1: rs1051266, rs1131596, rs3788200) of receptor genes related with the environment response, and the genotypes analysis was used to the correlation of receptor gene polymorphisms with risk suffering from adult AL. RESULTS: The unvariate logistic analysis showed that as compared with control group, P2X7 rs208294 T>C mutation and rs3751143 A>C mutation in codominant model, dominant model and over-dominant model were higher in case group, moreover the differences were statistically significant (P<0.01, P<0.05 and P<0.05, respectively), which suggested that they could reduce the risk suffering from AL. The recessive inheritance model showed that SLC1941 rs1131596 G>A mutation could increase the risk suffering from AL (P<0.05). The stepwise multivariate logistic regression analysis showed that there was still statistically significant difference in P2X7 rs208294 mutation between case group and control group (P<0.05), moreover, the heterozygous mutation (CT) could decrease the risk suffering from AL, showing the better protective effect, compared with homozygous mutation(CC). CONCLUSION The P2X7 rs208294 T>C mutation is one of protective factors against adult acute leukemia.
Adult ; Case-Control Studies ; Gene Frequency ; Genetic Predisposition to Disease ; Genotype ; Homozygote ; Humans ; Leukemia, Myeloid, Acute ; Polymorphism, Genetic ; Polymorphism, Single Nucleotide ; Receptors, Purinergic P2X7

Painful diabetic neuropathy (PDN) is a diabetes mellitus complication. Unfortunately, the mechanisms underlying PDN are still poorly understood. Adenosine triphosphate (ATP)-gated P2X7 receptor (P2X7R) plays a pivotal role in non-diabetic neuropathic pain, but little is known about its effects on streptozotocin (STZ)-induced peripheral neuropathy. Here, we explored whether spinal cord P2X7R was correlated with the generation of mechanical allodynia (MA) in STZ-induced type 1 diabetic neuropathy in mice. MA was assessed by measuring paw withdrawal thresholds and western blotting. Immunohistochemistry was applied to analyze the protein expression levels and localization of P2X7R. STZ-induced mice expressed increased P2X7R in the dorsal horn of the lumbar spinal cord during MA. Mice injected intrathecally with a selective antagonist of P2X7R and P2X7R knockout (KO) mice both presented attenuated progression of MA. Double-immunofluorescent labeling demonstrated that P2X7R-positive cells were mostly co-expressed with Iba1 (a microglia marker). Our results suggest that P2X7R plays an important role in the development of MA and could be used as a cellular target for treating PDN.
Acetamides/pharmacology* ; Animals ; Diabetes Mellitus, Experimental/complications* ; Diabetes Mellitus, Type 1/complications* ; Diabetic Neuropathies/etiology* ; Hyperalgesia/etiology* ; Male ; Mice ; Mice, Inbred C57BL ; Quinolines/pharmacology* ; Receptors, Purinergic P2X7/physiology* ; Spinal Cord/physiology* ; Streptozocin/pharmacology*

OBJECTIVE: Purinergic 2X7 receptor (P2X7R) activation is known to be involved in pathogenesis of depression. Our aims were to investigate P2X7R-activated inflammasome pathways in parallel with induction of depression and to test the antidepressant-like effects of the selective P2X7R antagonist Brilliant Blue G (BBG) in a rat model of chronic unpredictable mild stress (CUMS). METHODS: Male Wistar albino rats were divided into control, CUMS, CUMS+BBG25 (25 mg/kg/day) and CUMS+BBG50 (50 mg/kg/day) groups (n=10 for each group). Various stressors were applied to rats for 6 weeks to establish the CUMS model and daily BBG treatment was started at the end of 3rd week. Sucrose preference test and forced swim test (FST) were performed to assess antidepressant-like effects. Brain samples were obtained for real-time polymerase chain reaction and immunohistochemistry analysis. RESULTS: In FST, duration of immobility was reduced in the CUMS+BBG50 group. Also, BBG treatment significantly enhanced sucrose preference. While NLRP3 gene expression levels were unchanged in rats exposed to the CUMS protocol, expression levels of other inflammasome pathway factors NLRP1, caspase-1, ASC, NF-κB, IL-1β, IL-6 and P2X7R were increased. BBG treatment reduced expression levels of these factors. Likewise, Iba-1 and GFAP immunoreactivities were enhanced by the CUMS protocol and this action was reversed by BBG treatment. CONCLUSION: Chronic administration of BBG in CUMS model results in antidepressant-like activity in a dose dependent manner. Molecular and histological results show that these effects might be at least partially related to the suppression of inflammasome-related neuroinflammatory responses and suggest involvement of NLRP1 in depression.
Animals ; Brain ; Depression ; Gene Expression ; Humans ; Immunohistochemistry ; Inflammasomes ; Interleukin-6 ; Male ; Models, Animal ; Rats ; Real-Time Polymerase Chain Reaction ; Receptors, Purinergic P2 ; Receptors, Purinergic P2X7 ; Sucrose

OBJECTIVE: To study the diagnostic value of P2X7 receptor for rheumatoid arthritis (RA) and its role in the inflammatory response. METHODS: With the synovial tissues from 25 patients with bone and joint replacement as the control,the synovial tissues of 25 RA patients were examined for the relative expression of P2X7 receptor mRNA using qRT-PCR.In an immortalized RA synovial cell line (MH7A),the effect of P2X7 receptor knockdown via a small interfering RNA were examined on the productions of the inflammatory cytokines including interleukin-1β(IL-1β),IL-6,and IL-8 using ELISA. RESULTS: The RA patients showed significantly higher levels of P2X7 receptor mRNA expression in the synovial tissue than the control patients.P2X7 receptor had a good diagnostic value for RA.The expression levels of IL-1β,IL-6,and IL-8 were positively correlated with the levels of P2X7 receptor in the synovial tissues of RA patients (<0.001).In MH7A cells,P2X7 receptor knockdown obviously reduced the secretion of IL-1β and IL-6. CONCLUSIONS RA patients show elevated P2X7 receptor level in the synovial tissue, which has a good diagnostic value for RA.Blocking P2X7 receptor can inhibit inflammatory factor secretion and suppress inflammatory reactions.
Arthritis, Rheumatoid ; diagnosis ; physiopathology ; Case-Control Studies ; Cell Line ; Gene Knockdown Techniques ; Humans ; Inflammation ; metabolism ; Interleukin-1beta ; metabolism ; Interleukin-6 ; metabolism ; Interleukin-8 ; metabolism ; Purinergic P2X Receptor Antagonists ; RNA, Messenger ; metabolism ; Receptors, Purinergic P2X7 ; physiology ; Synovial Membrane ; metabolism

Background: The nucleotide-binding and oligomerization domain-like receptor protein 3 (NLRP3) inflammasome composed of NLRP3, apoptosis-associated speck-like protein containing CARD (ASC), and caspase-1 is engaged in the inflammatory response of many kidney diseases and can be activated by purinergic 2X7 receptor (P2X7R). This study was conducted to explore whether P2X7R plays a pathogenic role in the podocyte damage of obesity-related glomerulopathy (ORG) and whether this role is mediated by the activation of NLRP3 inflammasome. Methods: A mouse model of ORG was established by high-fat diet feeding. The conditionally immortalized mouse podocytes were cultured with leptin or with leptin and P2X7R antagonist (KN-62 or A438079). The mRNA and protein expression of the P2X7R and NLRP3 inflammasome components including NLRP3, ASC, and caspase-1, as well as the podocyte-associated molecules including nephrin, podocin, and desmin in mouse renal cortex or cultured mouse podocytes were tested by real-time-polymerase chain reaction and Western blot analysis, respectively. Results: The significantly upregulated expression of P2X7R and NLRP3 inflammasome components and the NLRP3 inflammasome activation were observed in the renal cortex (in fact their location in podocytes was proved by confocal microscopy) of ORG mice in vivo, which were accompanied with the morphological changes of podocyte damage and the expression changes of podocyte-associated molecules. Similar changes in the expression of P2X7R and NLRP3 inflammasome components as well as in the expression of podocyte-associated molecules were also observed in the cultured podocyte studies treated by leptin in vitro, and all of the above changes were significantly attenuated by the P2X7R antagonist KN-62 or A438079. Conclusions P2X7R could trigger the activation of NLRP3 inflammasome, and the activated P2X7R/NLRP3 inflammasome in podocytes might be involved in the podocyte damage of ORG.
Animals ; Blotting, Western ; Body Weight ; physiology ; Inflammasomes ; metabolism ; Kidney Glomerulus ; metabolism ; pathology ; Male ; Mice ; Mice, Inbred C57BL ; NLR Family, Pyrin Domain-Containing 3 Protein ; genetics ; metabolism ; Obesity ; complications ; Podocytes ; metabolism ; pathology ; Receptors, Purinergic P2X7 ; genetics ; metabolism

To investigate the protective effects of P2X7 receptor (P2X7R) inhibitor against cerebral ischemia/reperfusion (I/R) injury in rats and the possible mechanisms.
 Methods: The neurological deficit of rats was evaluated by Longa score. The infarct volume was examined by 2, 3, 5-triphenyltetrazolium chloride (TTC) staining. The expression levels of extracellular signal-regulated kinase (ERK), phosphorylation extracellular signal-regulated kinas p-ERK), connexin 43 (Cx43), Bax, Bcl-2 and cleaved caspase-3 were detected by Western blot.
 Results: Compared with sham group, the neurobehavioral score (P<0.05) and cerebral infarct volume (P<0.01) of rats in I/R group was increased. Compared with I/R group, brilliant blue G (BBG, the antagonist of P2X7R) or PD98059 (the inhibitor of EKR kinase) could reduce the neurobehavioral score (P<0.01) and cerebral infarct volume significantly (P<0.05). The neurobehavioral score and cerebral infarct volume was further decreased (P<0.05) when rats were treated with both BBG and PD98059. Compared with I/R group, the expression levels of p-ERK, Cx43, cleaved caspase-3 and the ratio of Bax/Bcl-2 were decreased by BBG or PD98059 pretreatment, and the protective effects were further enhanced when rats were treated with both BBG and PD98059 (P<0.05).
 Conclusion: Inhibition of P2X7R reduces the cerebral I/R injury of rats. ERK inhibition is probably involved in the protective effects of P2X7R inhibitor against cerebral I/R injury, which may be related to the reduction of Cx43 and cleaved caspase-3, and the ratio of Bax/Bcl-2.
Animals ; Brain Ischemia ; drug therapy ; prevention & control ; Gene Expression Regulation ; drug effects ; Phosphorylation ; drug effects ; Purinergic P2X Receptor Antagonists ; pharmacology ; therapeutic use ; Rats ; Receptors, Purinergic P2X7 ; Reperfusion Injury ; drug therapy ; prevention & control

P2X7 receptors are closely associated with inflammation, and they have been found to be expressed on colonic cells broadly. In animal model of colonic inflammation, ATP/P2X7 signaling mainly promotes inflammation, and a variety of cells, including macrophages, dendritic cells, T cells, mast cells and enteric neurons are involved in this process. However, in the toxoplasmic ileitis, P2X7 signaling plays a role in inhibiting the inflammation. But, the underlying mechanisms are still not clear. This review outlined the research progresses of P2X7 receptors in inflammatory bowel disease (IBD) to provide some clues for the further studies on the relationship between P2X7 receptors and IBD.
Animals ; Disease Models, Animal ; Inflammatory Bowel Diseases ; Macrophages ; Mast Cells ; Receptors, Purinergic P2X7 ; Signal Transduction ; T-Lymphocytes