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Purinergic 2X7 receptor (P2X7R) is an ionotropic receptor that is involved in various inflammatory diseases through affecting the release of inflammatory cytokines such as IL-1β and IL-18 after inducing the activation of nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3). In recent years, the P2X7R/NLRP3 signaling pathway has become one of the more studied pathways in inflammatory diseases, and some inhibitors of P2X7R and NLRP3 have already been used in early clinical treatment. In this paper, the progress in P2X7R and NLRP3 was summarized, aiming to provide reference for further investigation on the roles of P2X7R/NLRP3 in the pathogenesis of tumors and inflammatory diseases and the potential of P2X7R/NLRP3 as therapeutic targets.
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OBJECTIVE@#To observe the occurrence time of neuralgia and the expression of purinergic ligand-gated ion channel 7 receptor (P2X7R) in the dorsal horn of the spinal cord after intraperitoneal injection of streptozotocin (STZ) in diabetic rats, and to explore the effect of electroacupuncture (EA) and pretreatment of EA on the heat pain threshold and expression of P2X7R in the spinal dorsal horn in rats with diabetic neuropathic pain (DNP), and to explore the possible mechanism of EA for DNP.@*METHODS@#PartⅠ: Thirty male SD rats were randomly selected from 64 male SD rats as the control group; the remaining rats were given intraperitoneal injection of STZ (10 mg/mL) at a dose of 65 mg/kg to establish the diabetes model, and 30 rats were successfully modeled as the model group. The control group and the model group were divided into three subgroups respectively at 7, 14 and 21 days, with 10 rats in each subgroup. Body mass, fasting blood glucose (FBG) and thermal pain threshold were recorded at 7, 14 and 21 days after injection; the expression of P2X7R in spinal dorsal horn was detected by Western blot. PartⅡ: Eight SD rats were randomly selected from 35 male SD rats as the blank group, and the remaining 27 rats were given intraperitoneal injection of STZ (10 mg/mL) at a dose of 65 mg/kg to establish the diabetes model. The 24 rats with successful diabetes model were randomly divided into a DNP group, an EA group and a pre-EA group, 8 rats in each group. Fifteen to 21 days after STZ injection, the EA group received EA at "Zusanli" (ST 36) and "Kunlun" (BL 60), continuous wave, frequency of 2 Hz, 30 min each time, once a day; the intervention method in the pre-EA group was the same as that in the EA group. The intervention time was 8 to 14 days after STZ injection. The body mass, FBG and thermal pain threshold were recorded before STZ injection and 7, 14 and 21 days after STZ injection; the expression of P2X7R in spinal dorsal horn was detected by Western blot 21 days after injection.@*RESULTS@#PartⅠ: Compared with the control group, in the model group, the body mass was decreased and FBG was increased 7, 14 and 21 days after STZ injection (P<0.01), and the thermal pain threshold was decreased 14 and 21 days after STZ injection (P<0.05), and the expression of P2X7R in spinal dorsal horn was increased 7, 14 and 21 days after STZ injection (P<0.05, P<0.01). PartⅡ: Compared with the blank group, in the DNP group, the body mass was decreased and fasting blood glucose were increased 7, 14 and 21 days after STZ injection (P<0.01). Compared with the DNP group, in the pre-EA group, the heat pain threshold was increased 14 and 21 days after STZ injection (P<0.05), while in the EA group, the heat pain threshold was increased 21 days after STZ injection (P<0.01), and the expression of P2X7R in the dorsal horn in the EA group and the pre-EA group was decreased (P<0.01).@*CONCLUSION@#The diabetic neuropathic pain is observed 14 days after STZ injection. EA could not only treat but also prevent the occurrence of DNP, and its mechanism may be related to down-regulation of P2X7R expression in the dorsal horn of the spinal cord.
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Animals , Male , Rats , Diabetes Mellitus, Experimental/therapy , Electroacupuncture , Neuralgia/therapy , Rats, Sprague-Dawley , Spinal Cord , Spinal Cord Dorsal HornABSTRACT
The present study was designed to investigate the mechanisms by which P2X7 receptors (P2X7Rs) mediate the activation of vasopressinergic neurons thereby increasing sympathetic hyperactivity in the paraventricular nucleus (PVN) of the hypothalamus of rats with acute myocardial ischemia (AMI). The left anterior descending branch of the coronary artery was ligated to induce AMI in rats. The rats were pretreated with BBG (brilliant blue G, a P2X7R antagonist), nelivaptan (a vasopressin V1b receptor antagonist), or diphenyleneiodonium (DPI) [an nicotinamide adenine dinucleotide phosphate (NADPH) oxidase inhibitor]. Hemodynamic parameters of the heart were monitored. Myocardial injury and cardiomyocyte apoptosis were assessed. In the PVN of AMI rats, P2X7R mediated microglial activation, while reactive oxygen species (ROS) and NADPH oxidase 2 (NOX2) were higher than in the sham group. Intraperitoneal injection of BBG effectively reduced ROS production and vasopressin expression in the PVN of AMI rats. Moreover, both BBG and DPI pretreatment effectively reduced sympathetic hyperactivity and ameliorated AMI injury, as represented by reduced inflammation and apoptosis of cardiomyocytes. Furthermore, microinjection of nelivaptan into the PVN improved cardiac function and reduced the norepinephrine (AE) levels in AMI rats. Collectively, the results suggest that, within the PVN of AMI rats, P2X7R upregulation mediates microglial activation and the overproduction of ROS, which in turn activates vasopressinergic neuron-V1b receptors and sympathetic hyperactivity, hence aggravating myocardial injury in the AMI setting.
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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.
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Pancreatic cancer is one of the cancers with poor prognosis at present, which has high resistance to various anti-tumor drugs as a result of the interaction among pancreatic cancer cells, cancer stem cells, and the tumor microenvironment. P2X7 receptors are extracellular adenosine triphosphate(ATP)-gated nonselective cation channels, which have many biological functions including being involved in cell signal transduction and cytokine secretion, mediate cell survival and growth. Studies have shown that P2X7 receptor is highly expressed in pancreatic cancer and promotes the proliferation, migration and invasion of pancreatic cancer cells by supporting proliferation of pancreatic stellate cells and regulating the expressed of the MMP2/MMP9 protein. The paper reviews the recent research advances of P2X7 receptor in pancreatic cancer.
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Objective The activation of P2X7 receptor in ventrolateral periaqueductal gray (vlPAG) is involved in the formation and maintenance of bone cancer pain (BCP). This study will establish a rat model of BCP and observe the effect of the activation of P2X7 receptor in vlPAG on D-serine level through brain microdialysis combined with ELISA. Methods Forty-two female SD rats were divided into four groups by random number table: normal control group (n=12), sham group (n=12), BCP group (n=12) and P2X7 receptor antagonist group (n= 6). The model of metastatic BCP in the tibias of the rats was established in the BCP group, and 20μL of RPMI-1640 medium cell suspension containing SHZ-88 breast cancer cells was injected (1×107 cancer cells/0.5 mL). The sham group was injected with treated cancer cells of the same volume (SHZ-88 breast cancer cells were kept in boiling water at 90 ℃ for 20 min), and the rest of the operation was the same as the BCP group. The normal control group received no treatment. The P2X7 receptor antagonist group was treated the same as the BCP group, except that the P2X7 receptor-specific antagonist A-438079 was added to the perfusion solution. The thermal pain threshold and mechanical pain threshold were detected at the same time in the normal control group, the sham group and the BCP group. The positive expression of P2X7 receptor in vlPAG of rats was detected by immunohistochemistry in each group in 21 days. The changes of D-serine in vlPAG dialysate were detected by ELISA in each group. Results The mechanical pain threshold and thermal pain threshold of the rats in BCP group on Day 5, 7, 10, 14, 18 and 21 were lower than those of the normal control group and sham group (P<0.01). The positive expression of P2X7 was scattered in vlPAG in normal control group and sham group. The number of P2X7 receptor positive cells in the BCP group was significantly higher than that in the control group and sham group (P<0.01). The content of D-serine in vlPAG of the rats in BCP group [(220.28±63.38)ng/mL] was significantly higher than that in the control group [(148.09±46.89)ng/mL] and the sham group [(147.32±51.44)ng/mL] (P<0.05). The content of D-serine in vlPAG [(134.20±41.77)ng/mL] in P2X7 receptor antagonist group was significantly lower than that in BCP group (P<0.05). Conclusion The activation of the P2X7 receptor in ventrolateral periaqueductal gray promotes D-serine release and participates in the mechanisms of BCP in rats .
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Previous work has demonstrated that the sensitization of spinal neurons and microglia is important in the development of pain behaviors induced by BmK I, a Na channel activator and a major peptide component of the venom of the scorpion Buthus martensi Karsch (BmK). We found that the expression of P2X7 receptors (P2X7Rs) was up-regulated in the ipsilateral spinal dorsal horn after BmK I injection in rats. P2X7R was selectively localized in microglia but not astrocytes or neurons. Similarly, interleukin 1β (IL-1β) was selectively up-regulated in microglia in the spinal dorsal horn after BmK I injection. Intrathecal injection of P2X7R antagonists largely reduced BmK I-induced spontaneous and evoked pain behaviors, and the up-regulation of P2X7R and IL-1β in the spinal cord. These data suggested that the up-regulation of P2X7Rs mediates microglial activation in the spinal dorsal horn, and therefore contributes to the development of BmK I-induced pain.
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Objective To investigate the effect of microRNA-22 (miRNA-22) on the expression of P2X7 receptor and inflammatory factors in hippocampus of rats with epilepsy. Methods Healthy SD male rats were intraperitoneal injected with lithium chloride and pilocarpine to induce epilepsy. Three days later, 45 epileptic rats were randomly divided into three groups: epilepsy group( EP group), miRNA-22 agomir group (EF+agomir group) and miRNA-22 agomir control group ( EF+agomir control group). Another 15 healthy rats were selected as control group(N group). The expression of P2X7 protein was detected by West- ern blot and the levels of miRNA-22, P2X7 mRNA, NF-κB mRNA ,IL-1β mRNA were detected by qRT-PCR. Nissl staining was used to observe the damage of Nissl bodies. Results Western blot result showed that compared with the N group(0. 91±0. 10), the level of P2X7 protein in EP group (1. 17±0. 052) in-creased, and the difference was statistically significant (t=-4. 11,P=0. 02). Compared with the EP+ag-omir control group(0. 94± 0. 14),the expression of P2X7 protein in EP+agomir group (0. 66± 0. 06) de-creased and the difference was significant (t=-3. 10,P=0. 04). And the qRT-PCR results showed that compared with N group, the levels of P2X7mRNA (9. 08±0. 94), NF-κB mRNA (20. 10±2. 15) and IL-1β mRNA (50. 64±5. 42) in EP group increased(t=-14. 96,P<0. 05; t=-15. 38,P<0. 05; t=-15. 87,P<0. 05). The expression of P2X7mRNA (1. 31 ± 0. 64), NF-κB mRNA ( 2. 28 ± 1. 10) and IL-1β mRNA (2. 12±1. 20) in EF+agomir group decreased compared with EP group((9. 08± 0. 94),( 20. 10± 2. 15), (50. 64±5. 42)) and EF+agomir control group((7. 03 ±1. 90),(18. 72±1. 76),(47. 39±6. 16)), and the differences were statistically significant(F=29. 77, P<0. 01;F=98. 99, P<0. 05;F=96. 29, P<0. 01). Nissl staining results showed that a large number of morphologically abnormal and disintegrated Nissl bodies could be observed in the hippocampal CA1 and CA3 regions of EP group,which showed a smaller size,irreg-ular morphology,chromatin pyknosis,boundary blur between nucleus and cytoplasm. Compared with the nor-mal group, the difference was significant (P<0. 05). While in miRNA-22 agomir group, the disintegration of Nissl bodies was improved and the number of Nissl bodies increased. Conclusion Intraventricular injec-tion of miRNA-22 agomir can down-regulate the expression of P2X7 receptor and related inflammatory factors in hippocampus of epileptic rats, thus inhibiting seizures.
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The ATP-gated ionotropic P2X7 receptor has been widely concerned in recent years. Upon activation by ATP and its derivatives, P2X7 receptor induces a series of responses such as activation of PANX1 and release of IL-lg. Elucidation of the role and mechanism of P2X7 receptor in pain would provide ideas for the development of new and effective analgesic drugs. This review discusses the recent progress of P2X7 receptor in inflammatory pain, neuropathic pain, cancer pain, and morphine tol-erance , and summarizes the possible mechanism of P2X7 receptor involved in the modulation of pain.
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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.
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Humans , Arthritis, Rheumatoid , Diagnosis , Case-Control Studies , Cell Line , Gene Knockdown Techniques , Inflammation , Metabolism , Interleukin-1beta , Metabolism , Interleukin-6 , Metabolism , Interleukin-8 , Metabolism , Purinergic P2X Receptor Antagonists , RNA, Messenger , Metabolism , Receptors, Purinergic P2X7 , Physiology , Synovial Membrane , MetabolismABSTRACT
Aim To investigate the role of P2X7 recep-tor and its mediated NLRP3 inflammatory signaling pathway in alcohol-induced liver injury. Methods The acute alcoholic liver injury model was established by NIAAA method, and thirty C57BL/6 male mice were randomly divided into three groups (n =10):control group, model group, A438079 group, The three groups were processed as follows in the last week:control group and model group: given an equal dose of saline intraperitoneal injection(about 0.2 mL/only) once a day. According to the weight of the mice, A438079 group was given intraperitoneally injection by 200 μmol·kg-1of A-438079 (prepared at 7 g·L-1 of A438079,about 0.2 mL/only) once a day. And it was given a single 31.5% alcohol solution by intragas-tric administration on the last day of the morning,with the dose of 10 mL·kg-1. Nine hours later alanine aminotransferase (ALT), aspartate aminotransferase (AST),cholesterol(TCHO),triglyceride(TG) were measured by orbital blood in mice. HE staining was used to observe the pathological changes of the liver. Immunohistochemical method was applied to detect the expression of P2X7R in liver tissues. Western blot was employed to detect the levels of P2X7R, NLRP3, ASC, IL-1β and IL-18 in liver tissues. Results Compared with control group,the levels of ALT,AST, TG and TCHO in model group were significantly en-hanced, and the liver injury was obvious. Compared with model group, the levels of ALT, AST, TG and TCHO in A438079 group significantly decreased. Compared with control group, the expressions of P2X7, NLRP3, ASC, IL-1β, IL-18 in model group were significantly higher than those in control group. Compared with model group, the expression levels of P2X7, NLRP3, ASC, IL-1β and IL-18 in A438079 group significantly decreased. Conclusion Alcohol-induced liver injury may be associated with P2X7R-NLRP3 signaling pathway.
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Objective The mechanisms underlying neuropathic pain are complicated and the clinical effect of analgesia therap on this condition is not quite satisfactory.In this study, we observed the analgesic effects of the different doses of tramadol (T ) on neuropathic pain in rats and explored its action mechanisms . Mehtods The model of chronic sciatic nerve constriction injury (CC)I was established in male SD rats.The rats were randomly divided into five groups , sham operation ,CCI model control, low-dose T, mediumdose T, and high-dose T ,those in the latter three groups injected intraperitoneally with T at 5 , 15,and 25mg /kg qd ,respectively ,from the 7th to the 14th day after modeling.The mechanical and thermal pain thresholds of the nerve -injured hindleg were measured pre-operatively and at1 ,5 , 7, 10, 12and 14 days post-operatively.At 14 days after modeling, the expression of the P2X7receptor in the spinal dorsal horn was detected by immunohistochemistry and Western blot . Results At 5, 7,10 , 12 and 14 days after modeling,the mechanical pain threshold values were significantly decreased in the rats of the CCI model control group ([34.97±3.86 ],[34.06 ±3.79], [ 33.27±3.65], [29.03±3 . 54], and [17.90±2.34] g) and high-dose Tgroup([ 34.87±3.85], [33.47±3.66],[34 .50±3. 78 ], [29.43±3.64], and [18.63±2.42] g) as compared with the animals of the sham operation group ([39.73±5.55],[39.50±5.51], [40.97±5. 58], [41.87±5.60], and [42.97±6.75] g) (all P<0.01), and so were the thermal pain threshold valuesin the CCI model control group ([35 .21±3.94], [35.16±3.80], [29.74±2. 76], [ 20. 47±2.16], and[12.08±1.48] s) and high -dose T group ([35.76±3.76], [33.27±3.52], [31.22±3.05], [19.41±2.08], and [10.35±1.34] s) in comparison with the shamoperation group ([39.69±4.86], [39.21±4.82], [39.42±5.08], [41.17±4.88], and [42.53±5.12] s) (all P<0. 01 ).The number of the P2X7receptor positive cells and the ROD value of the P 2X7 receptor protein in the spinal dorsal horn were remarkably higher in the CCI model control than in the sham operation , low-dose T and medium-dose T groups (all P<0.01). Conclusion Intraperitoneal injection of low-dose tramadol has an analgesic effect on neuropathic pain in rats , which may be related to its decreasing effect on theexpression of the P2X7 receptor in the spinal dorsal horn.
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Objective:To investigate the dynamic expression and spatial distribution of P2X7 receptor in pilocarpine-induced epileptic rat hippocampus.Methods:Status epilepticus (SE) model of rats was established by intraperitoneal injection with chloride lithium and pilocarpine.Rat brain tissue and hippocampus were collected at 1,3,7,14,28 days after SE.The protein expression of P2X7 receptor in rat hippocampus was detected by Western blot.The distribution of P2X7 receptor in hippocampal sub-region was analyzed by immunohistochemistry.Results:Bilateral forelimb clonus appeared at (33.9±12.3 min after intraperitoneal injection with pilocarpine.The protein expression of P2X7 receptor was increased at 1d after SE,while it was decreased gradually from 3 d to minimum at 7 d,then it was elevated continuously to 28 d.Among them,the expression of P2X7 receptor was increased significantly at 1,14 and 28 d post-SE (P＜0.05).Immunohistochemical staining showed that P2X7 receptor was detected in all areas.The expression pattern of P2X7 receptor in hippocampal DG and CA3 area was consistent with protein expression,but its expression in hippocampal CA1 area was not significantly changed after SE.Conclusion:The expression of P2X7 receptor in post-SE hippocampus is in a time-dependent manner and spatial specificity.P2X7 receptor might be involved in the development of chronic epilepsy.
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AIM:To investigate the neuroprotective effect of progesterone against adenosine triphosphate (ATP)-injured human neuroblastoma SH-SY5Y cells.METHODS:The SH-SY5Y cells in the logarithmic phase were divided into different groups according to the progesterone and ATP concentrations.The cell viability was measured by CCK-8 assay.The membrane permeability was detected using fluorescent dye YO-PRO-1.Cytosolic Ca2+ concentration was measured with fluorescent dye Fluo-3/AM.The expression of purinergic P2X7 receptor was assessed by Western blot.RESULTS:The viability of the SH-SY5Y cells was significantly decreased (P ＜ 0.05) and YO-PRO-1 uptake was obviously increased (P ＜ 0.05) in a concentration-dependent manner compared with control group when SH-SY5Y cells were treated with ATP at 1,3,5 and 7 mmol/L for 2 h.The viability reduction of the SH-SY5Y cells induced by ATP was obviously counteracted by treatment with progesterone at 3,10 and 30 nmol/L for 30 min (P ＜ 0.05) as compared with ATP group.YO-PRO-1 fluorescence enhancement induced by ATP in SH-SY5Y cells was significantly reduced (P ＜ 0.05) by progesterone (30 nmol/L) or P2X7 receptor antagonist KN-62 (500 nmol/L) pretreatment for 30 min,and no obvious difference between treatments with progesterone and KN-62 was observed.Cytosolic Ca2+ fluorescence intensity in normal group was a little,but that in ATP group was increased (P ＜ 0.05).Progesterone or KN-62 pretreatment significantly decreased the cytosolic fluorescence intensity of Ca2+ induced by ATP (P ＜ 0.05).However,no obvious difference between treatments with progesterone and KN-62 was found.The expression of P2X7 receptor in ATP group was significantly higher than that in control group (P ＜ 0.05),and progesterone inhibited ATP-induced P2X7 receptor expression (P ＜ 0.05).CONCLUSION:Progesterone inhibits P2X7 receptor expression,membrane pore formation,intracellular Ca2+ increase and cell death induced by ATP,so progesterone may protect SH-SY5Y cells against ATP-induced injuries.
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AIM:To investigate the neuroprotective effect of progesterone against adenosine triphosphate (ATP)-injured human neuroblastoma SH-SY5Y cells.METHODS:The SH-SY5Y cells in the logarithmic phase were divided into different groups according to the progesterone and ATP concentrations.The cell viability was measured by CCK-8 assay.The membrane permeability was detected using fluorescent dye YO-PRO-1.Cytosolic Ca2+ concentration was measured with fluorescent dye Fluo-3/AM.The expression of purinergic P2X7 receptor was assessed by Western blot.RESULTS:The viability of the SH-SY5Y cells was significantly decreased (P ＜ 0.05) and YO-PRO-1 uptake was obviously increased (P ＜ 0.05) in a concentration-dependent manner compared with control group when SH-SY5Y cells were treated with ATP at 1,3,5 and 7 mmol/L for 2 h.The viability reduction of the SH-SY5Y cells induced by ATP was obviously counteracted by treatment with progesterone at 3,10 and 30 nmol/L for 30 min (P ＜ 0.05) as compared with ATP group.YO-PRO-1 fluorescence enhancement induced by ATP in SH-SY5Y cells was significantly reduced (P ＜ 0.05) by progesterone (30 nmol/L) or P2X7 receptor antagonist KN-62 (500 nmol/L) pretreatment for 30 min,and no obvious difference between treatments with progesterone and KN-62 was observed.Cytosolic Ca2+ fluorescence intensity in normal group was a little,but that in ATP group was increased (P ＜ 0.05).Progesterone or KN-62 pretreatment significantly decreased the cytosolic fluorescence intensity of Ca2+ induced by ATP (P ＜ 0.05).However,no obvious difference between treatments with progesterone and KN-62 was found.The expression of P2X7 receptor in ATP group was significantly higher than that in control group (P ＜ 0.05),and progesterone inhibited ATP-induced P2X7 receptor expression (P ＜ 0.05).CONCLUSION:Progesterone inhibits P2X7 receptor expression,membrane pore formation,intracellular Ca2+ increase and cell death induced by ATP,so progesterone may protect SH-SY5Y cells against ATP-induced injuries.
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Objective To investigate the role of purinergic 2X7 receptor (P2X7R) and its downstream target-NLRP3 inflammasome activation in the process of pancreatic fibrosis in a mouse model of chronic pancreatitis (CP). Methods Forty C57BL/6 mice were randomly divided into normal control group, CP group, P2X7R antagonist oxidized ATP (OxATP) group and brilliant blue G (BBG) group. The chronic pancreatitis model was induced by repeated intraperitoneal injection of the cholecystokinin analogue caerulein with the dose of 50μg/kg for six weeks. Normal saline, OxATP (20μL, 300μmol/L) or BBG (20μL, 10μmol/L) were administered for CP group, OxATP group and BBG group for two weeks after the last caerulein injection. Then all mice were sacrificed and the histopathological changes of the pancreas, especially the fibrotic degrees were evaluated by HE stain, fibrosis score, Sirius red staining and α-SMA immunohistochemical stain. The pancreatic P2X7R, NLRP3 and Caspase-1 expressions were detected by immunohistochemistry respectively to compare the changes between the groups, and explore the role of P2X7R-NLRP3 signaling pathway in pancreatic fibrosis. Results Compared with the normal control group, the scores of pancreatic fibrosis and the expressions of P2X7R, NLRP3 and Caspase-1 in pancreas were significantly increased in CP model group (P<0.05). Compare to CP group, the pancreatic chronic inflammation and the fibrosis indices such as HE fibrosis score, Sirius red staining and α-SMA immunohistochemical stain were ameliorated obviously in OxATP and BBG groups (P<0.05). And expressions of P2X7R, NLRP3 and Caspase-1 in the pancreas were allreduced greatly in both OxATP and BBG groups (P<0.05). Conclusion P2X7R antagonist OxATP and BBG can significantly decrease pancreatic chronic inflammation and fibrosis in the mouse model of CP, which suggests that the blockade of P 2X7R-NLRP3 inflammasome signaling pathway may represent a novel therapeutic strategy for CP and its fibrotic process.
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Objective To observe the distribution and possible mechanism of P2X7R in periaq-ueductal gray matter (PAG)in a rat model with chronic neuropathic pain in vivo.Methods The in-trathecal catheterization and sciatic nerve injury (SNI)were performed.All animals were randomly assigned into 3 groups with 26 rats in each,which was group Sham,control group (group C)and brilliant blue G (BBG)group (group BBG),respectively.Normal saline or BBG 10 μl were intrathe-cally injected after SNI and repeated for seven days.Paw-withdrawal mechanical thresholds (PWT) were measured on day 0,day 7,day 14,and day 21 after SNI.The rats were sacrificed and PAG tis-sues were collected on day 14 and day 21,separately.The distributions of P2X7R were observed by immunofluorescence.The protein contents of P2X7R and GFAP were assessed by Western blot assays.Results The P2X7R was expressed in PAG in rats.The PWTs of the control group showed a significant decrease during the 21-day period compared with the sham group.The P2X7R signals were predominantly expressed in astrocytes in PAG after SNI.Both P2X7R and GFAP expression remark-ably increased.Administration of BBG increased the PWTs,and inhibited the P2X7R and GFAP ex-pressions compared with those atthe same point of time of the control group.Conclusion These results indicated that P2X7R in PAG might participate in nociception modulation in the midbrain in chronic neuropathic pain.
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Objective To investigate the expression of P2X7 receptor (P2X7R) and the effect of P2X7R agonist 2'-3'-O-(4-benzoyl-benzoyl) ethane adenosine triphosphate three amine salt (BzATP) on cell growth and apoptosis in non-small cell lung cancer A549 cells,and to explore the related mechanism.Methods The expression of P2X7R in A549 cells was detected by immunofluorescence.Cells were treated with different concentrations (150,300,600 μmol/L) of BzATP.Cells untreated with BzATP were used as control group.3-(4,5-dimethyl-2-thiazoly)-2,5-diphenyl-2H-tetrazolium bromide (MTF) assay and Hoest33342 staining were respectively used to detect cell viability and apoptosis.Enzyme-linked immunosorbent assay (ELISA) was uesd to detect the concentration of tumor necrosis factor-α (TNF-α) of cell culture supernatants.The expressions of nuclear factor-κB (NF-κB) p65,inhibitor of α of NF-κB (IκBα) and the phosphorylation of inhibitor of α of NF-κB (phospho-IκBα) were detected by Western blotting.Results P2X7R was expressed on the cell membrane of A549 cells.Survival rate of A549 cell was significantly decreased with the concentrations of BzATP at 300 and 600 μmol/L [(67.87 ± 8.98) ％,(44.73 ± 6.92) ％],compared with the control group (98.60 ± 1.44) ％,the differences were statistically significant (t =4.481,P =0.027;t =3.920,P =0.038).BzATP promoted apoptosis,and increased the concentration of TNF-α of supernatant at 300 and 600 μmol/L [(57.35 ±6.41) pg/ml,(78.63 ± 11.33) pg/ml],compared with the control group (42.56 ±0.37) pg/ml,the differences were statistically significant (t =6.410,P =0.035;t =11.330,P =0.005).In addation,the expressions of NF-κB p65 and IκBα were respectively downregulated and upregulated by BzATP,while the expression of phospho-IκBα was not significantly altered.Conclusion P2X7R is expressed on A549 cell membrane.BzATP can inhibit cell proliferation and induce the apoptosis of A549 cells,and the mechanism of action may be related to promoting the release of TNF-α and inhibition of NF-κB pathway.
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P2X7 receptor, an ATP-gated ion channel, is widely found in various tissues and possesses multiple physiological functions. Recent reports have implicated expression of P2X7 receptor in both osteoblasts and osteoclasts, participating in both bone formation and resorption. This paper reviews the recent progresses on the influence of P2X7 receptor and its related pathways on bone metabolism.
ABSTRACT
Objective To investigate the role of P2X7 receptor in learning and memory dysfunction induced by HIV-1 enveloped protein gp120 in rats. Methods The imitating HIV-1 associated dementia (HAD) animal models were established by intracerebroventricular (ICV) infusion of gp120 in rats. The effect of gp120 on the learning and memory dysfunction in rats was evaluated by Morris water maze (MWM) test. The role of P2X7 receptor (P2X7R) was studied by Western blot and PCR assay. Results The ICV infusion of gp120 for 3 days in rats could imitated the HAD animal model. Results of MWM test showed that the rats in the model group had longer escape latencies and errors compared with those in the control group (P < 0.01); Results of Western blot and PCR assay showed that the expressions of P2X7R and P2X7 mRNA in hippocampus of rats in the model group were significantly increased (P < 0.01). Conclusions The ICV infusion of gp120 in rats could imitate the HIV-1 associated dementia (HAD) animal models, and P2X7R may be involved in the pathophysiological process of learning and memory dysfunction caused by gp120.