OBJECTIVETo clone the entire coding sequence and analyze the function of P2X7 receptor of J6-1 human leukemia cells.

METHODSThe entire coding sequence of P2X7 receptor was amplified by RT-PCR and then inserted into pTARGET plasmid to construct an eukaryotic expressing plasmid followed by DNA sequencing. HEK293 cells stably expressing P2X7 receptor were obtained after transfection and screening, and confirmed by RT-PCR and Western blotting. The bleb formation upon agonist stimulation was observed under phase contrast microscope.

RESULTSThe entire coding sequence of P2X7 receptor of J6-1 cells was successfully cloned. DNA sequencing analysis revealed a substitution of G559, for A559, causing a substitution of Glu187 for Gln187. The P2X7 receptor derived from J6-1 cells could be functionally expressed in HEK293 cells, in which bleb formation could be detected upon stimulation.

CONCLUSIONSThe entire coding sequence of P2X7 receptors was successfully cloned from J6-1 leukemia cells. Other unknown mechanism may contribute to the dysfunction of P2X7 receptor in these cells.

Cell Line, Tumor ; Cloning, Molecular ; DNA, Complementary ; genetics ; Gene Expression ; Humans ; Leukemia ; genetics ; metabolism ; Receptors, Purinergic P2 ; genetics ; physiology ; Receptors, Purinergic P2X7 ; Reverse Transcriptase Polymerase Chain Reaction ; Transfection

Adenosine Triphosphate ; physiology ; Animals ; Astrocytes ; physiology ; Calcium Signaling ; Cell Communication ; Glutamic Acid ; physiology ; Humans ; Neurons ; physiology ; Receptors, G-Protein-Coupled ; physiology ; Receptors, Glutamate ; physiology ; Receptors, Purinergic P2 ; physiology ; Receptors, Purinergic P2X7

Regulation of P2X7 receptor expression is of interest because activation of this receptor by extracellular ATP triggers a wide variety of cell functions in leukocytes. However, its expression and modulation in human peripheral blood mononuclear cells (PBMC) and monocytes remain unclear. RT-PCR was used to detect the constitutive level of P2X7 receptor and the levels upon stimulation with bacteria, bacterial product, mitogen and various cytokines in human PBMC and monocytes. P2X7 receptor mRNA was detected in PBMC and monocytes. P2X7 receptor expression in PBMC was up-regulated by interleukin-2, -4, -6 (IL-2, IL-4, IL-6) tumour necrosis factor-alpha (TNF-alpha), lipopolysaccharide (LPS) and heat-inactivated Staphylococcus aureus Cowan strain I (SAC). However, interferon-gamma (IFN-gamma), granulocyte-macrophage colony-stimulating factor (GM-CSF), macrophage colony-stimulating factor (M-CSF) and phytohemagglutinin-M (PHA-M) had little effect on the expression of P2X7 receptor. Furthermore, LPS and M-CSF could up-regulate P2X7 receptor expression in monocytes, while IFN-gamma, TNF-alpha and GM-CSF had weak effects, but pretreatment with these inducers could not further enhance LPS-stimulated P2X7 receptor expression in monocytes. The results obtained demonstrate that inflammatory stimuli drive P2X7 expression, thus supporting the hypothesis that P2X7 receptor may play a role in the inflammatory responses against bacteria infection, which need further verification.
Humans ; Interleukin-2 ; physiology ; Interleukin-4 ; physiology ; Leukocytes, Mononuclear ; drug effects ; metabolism ; RNA, Messenger ; genetics ; metabolism ; Receptors, Purinergic P2X7 ; genetics ; metabolism ; Tumor Necrosis Factor-alpha ; physiology

BACKGROUNDThe mechanism of the neural injury caused by chronic intermittent hypoxia (CIH) that characterizes obstructive sleep apnea syndrome (OSAS) is not clearly known. The purpose of this study was to investigate whether P2X7 receptor (P2X7R) is responsible for the CIH-induced neural injury and the possible pathway it involves.

METHODSEight-week-old male C57BL/6 mice were used. For each exposure time point, eight mice divided in room air (RA) and IH group were assigned to the study of P2X7R expression. Whereas in the 21 days-Brilliant Blue G (BBG, a selective P2X7R antagonist) study, 48 mice were randomly divided into CIH group, BBG-treated CIH group, RA group and BBG-treated RA group. The hippocampus P2X7R expression was determined by Western blotting and real-time polymerase chain reaction (PCR). The spatial learning was analyzed by Morris water maze. The nuclear factor kappa B (NFκB) and NADPH oxidase 2 (NOX2) expressions were analyzed by Western blotting. The expressions of tumor necrosis factor α, interleukin 1β (IL-β), IL-18, and IL-6 were measured by real-time PCR. The malondialdehyde and superoxide dismutase levels were detected by colorimetric method. Cell damage was evaluated by Hematoxylin and Eosin staining and Terminal Transferase dUTP Nick-end Labeling method.

RESULTSThe P2X7R mRNA was elevated and sustained after 3-day IH exposure and the P2X7R protein was elevated and sustained after 7-day IH exposure. In the BBG study, the CIH mice showed severer neuronal cell damage and poorer performance in the behavior test. The increased NFκB and NOX2 expressions along with the inflammation injury and oxidative stress were also observed in the CIH group. BBG alleviated CIH-induced neural injury and consequent functional deficits.

CONCLUSIONSThe P2X7R antagonism attenuates the CIH-induced neuroinflammation, oxidative stress, and spatial deficits, demonstrating that the P2X7R is an important therapeutic target in the cognition deficits accompanied OSAS.

Animals ; Disease Models, Animal ; Hypoxia ; Male ; Metabolic Networks and Pathways ; Mice ; Mice, Inbred C57BL ; Purinergic P2 Receptor Antagonists ; pharmacology ; Receptors, Purinergic P2X7 ; analysis ; physiology ; Rosaniline Dyes ; pharmacology ; Sleep Apnea, Obstructive ; metabolism

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

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*

This study is to investigate the effects of indirubin on ATP-induced immune responses of macrophages. For this, neutral red dye uptake method was used to test phagocytosis, MTT assay was used for measuring cell death, and reactive oxygen species (ROS) was tested with fluorescent probe DHE. The data showed that extracellular ATP attenuated phagocytosis, induced cell death and increased ROS production, and these effects were restored by pre-treating with indirubin. This result suggested that indirubin blockade the effects of ATP on macrophages, because extracellular ATP-induced effects are dependent on P2 receptors, in particular P2X7 receptors. Furthermore, the effects of indirubin on the activation of P2 receptors were tested, in particular P2X7 receptors. The data showed that indirubin significantly decreased ATP-induced, P2 receptors mediated intracellular Ca2+ concentration ([Ca2+]i) rise and inhibited P2X7 receptor-based ethidium bromide (EB) dye uptake. These results suggested the inhibitory effects of indirubin on the activation of P2X7 receptors, which may underlying the effects on ATP induced ROS production, phagocytosis attenuation and cell death of macrophages.
Adenosine Triphosphate ; pharmacology ; Animals ; Calcium ; metabolism ; Cell Death ; drug effects ; Indoles ; pharmacology ; Macrophages ; cytology ; metabolism ; physiology ; Male ; Phagocytosis ; drug effects ; Rats ; Rats, Wistar ; Reactive Oxygen Species ; metabolism ; Receptors, Purinergic P2X7 ; 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

Microglia are the principal immune effectors in brain and participate in a series ofneurodegenerative diseases. The microglial shapes are highly plastic. The morphology is closely related with their activation status and biological functions. Cerebral ischemia could induce microglial activation, and microglial activation is subjected to precise regulation. Microglia could play either protective or neurotoxic roles in cerebral ischemia. Therefore, regulating the expression of receptors or protein molecules on microglia, inhibiting the excessive activation of microglia and production of pro-inflammatory factors, promoting the release of neuroprotective substances might be beneficial to the treatment of cerebral ischemia. The study about relationship between microglia and cerebral ischemia will shed a light on the treatment of cerebral ischemia. This paper is a review of microglial activation and regulation during cerebral ischemia as well as related therapeutic methods.
Animals ; Brain Ischemia ; metabolism ; pathology ; Class Ib Phosphatidylinositol 3-Kinase ; metabolism ; Humans ; Inflammation ; metabolism ; Microglia ; cytology ; drug effects ; metabolism ; physiology ; Neuroprotective Agents ; pharmacology ; Nitric Oxide Synthase ; metabolism ; Receptors, Purinergic P2X7 ; metabolism ; Regeneration ; TNF-Related Apoptosis-Inducing Ligand ; metabolism ; Toll-Like Receptors ; metabolism