Sleep Deprivation Selectively Down-Regulates Astrocytic 5-HT2B Receptors and Triggers Depressive-Like Behaviors via Stimulating P2X7 Receptors in Mice

Chronic loss of sleep damages health and disturbs the quality of life.Long-lasting sleep deprivation(SD)as well as sleep abnormalities are substantial risk factors for major depressive disorder,although the underlying mechanisms are not clear.Here,we showed that chronic SD in mice promotes a gradual elevation of extracellular ATP,which activates astroglial P2X7 receptors(P2X7Rs).Activated P2X7Rs,in turn,selectively down-regulated the expression of 5-HT2B receptors(5-HT2BRs)in astrocytes.Stimulation of P2X7Rs induced by SD selectively suppressed the phosphorylation of AKT and FoxO3 a in astrocytes,but not in neurons.The overexpression of FoxO3a in astrocytes inhibited the expression of 5-HT2BRs.Down-regulation of 5-HT2BsRs instigated by SD suppressed the activation of STAT3 and relieved the inhibition of Ca2+-dependent phospholipase A2.This latter cascade promoted the release of arachidonic acid and prostaglandin E2.The depression-like behaviors induced by SD were alleviated in P2X7R-KO mice.Our study reveals the mechanism underlying chronic SD-induced depression-like behaviors and suggests 5-HT2BRs as a key target for exploring therapeutic strategies aimed at the depression evoked by sleep disorders.

Paraventricular Nucleus P2X7 Receptors Aggravate Acute Myocardial Infarction Injury via ROS-Induced Vasopressin-V1b Activation in Rats

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.

Study of the roles of caspase-3 and nuclear factor kappa B in myenteric neurons in a P2X7 receptor knockout mouse model of ulcerative colitis

BACKGROUND The literature indicates that the enteric nervous system is affected in inflammatory bowel diseases(IBDs)and that the P2X7 receptor triggers neuronal death.However,the mechanism by which enteric neurons are lost in IBDs is unknown.AIM To study the role of the caspase-3 and nuclear factor kappa B(NF-κB)pathways in myenteric neurons in a P2X7 receptor knockout(KO)mouse model of IBDs.METHODS Forty male wild-type(WT)C57BL/6 and P2X7 receptor KO mice were euthanized 24 h or 4 d after colitis induction by 2,4,6-trinitrobenzene sulfonic acid(colitis group).Mice in the sham groups were injected with vehicle.The mice were divided into eight groups(n=5):The WT sham 24 h and 4 d groups,the WT colitis 24 h and 4 d groups,the KO sham 24 h and 4 d groups,and the KO colitis 24 h and 4 d groups.The disease activity index(DAI)was analyzed,the distal colon was collected for immunohistochemistry analyses,and immunofluorescence was performed to identify neurons immunoreactive(ir)for calretinin,P2X7 receptor,cleaved caspase-3,total caspase-3,phospho-NF-κB,and total NF-κB.We analyzed the number of calretinin-ir and P2X7 receptor-ir neurons per ganglion,the neuronal profile area(μm^(2)),and corrected total cell fluorescence(CTCF).RESULTS Cells double labeled for calretinin and P2X7 receptor,cleaved caspase-3,total caspase-3,phospho-NF-κB,or total NF-κB were observed in the WT colitis 24 h and 4 d groups.The number of calretinin-ir neurons per ganglion was decreased in the WT colitis 24 h and 4 d groups compared to the WT sham 24 h and 4 d groups,respectively(2.10±0.13 vs 3.33±0.17,P<0.001;2.92±0.12 vs 3.70±0.11,P<0.05),but was not significantly different between the KO groups.The calretinin-ir neuronal profile area was increased in the WT colitis 24 h group compared to the WT sham 24 h group(312.60±7.85 vs 278.41±6.65,P<0.05),and the nuclear profile area was decreased in the WT colitis 4 d group compared to the WT sham 4 d group(104.63±2.49 vs 117.41±1.14,P<0.01).The number of P2X7 receptor-ir neurons per ganglion was decreased in the WT colitis 24 h and 4 d groups compared to the WT sham 24 h and 4 d groups,respectively(19.49±0.35 vs 22.21±0.18,P<0.001;20.35±0.14 vs 22.75±0.51,P<0.001),and no P2X7 receptor-ir neurons were observed in the KO groups.Myenteric neurons showed ultrastructural changes in the WT colitis 24 h and 4 d groups and in the KO colitis 24 h group.The cleaved caspase-3 CTCF was increased in the WT colitis 24 h and 4 d groups compared to the WT sham 24 h and 4 d groups,respectively(485949±14140 vs 371371±16426,P<0.001;480381±11336 vs 378365±4053,P<0.001),but was not significantly different between the KO groups.The total caspase-3 CTCF,phospho-NF-κB CTCF,and total NF-κB CTCF were not significantly different among the groups.The DAI was recovered in the KO groups.Furthermore,we demonstrated that the absence of the P2X7 receptor attenuated inflammatory infiltration,tissue damage,collagen deposition,and the decrease in the number of goblet cells in the distal colon.CONCLUSION Ulcerative colitis affects myenteric neurons in WT mice but has a weaker effect in P2X7 receptor KO mice,and neuronal death may be associated with P2X7 receptor-mediated caspase-3 activation.The P2X7 receptor can be a therapeutic target for IBDs.

Role of P2X_7 receptors in neuronal death in the retina

Acknowledgments： I would like to express my appreciation to Professor Puro DG for leading me to this research topic during my stay as a research fellow in his laboratory at the University of Michigan in 2001, and also to Professor Ikeda T forgiving me the opportunity to study abroad and then to continue to investigate this topic in the Department of Ophthalmology at Osaka Medical College, lapan.

Enteric nervous system and inflammatory bowel diseases:Correlated impacts and therapeutic approaches through the P2X7 receptor

The enteric nervous system(ENS)consists of thousands of small ganglia arranged in the submucosal and myenteric plexuses,which can be negatively affected by Crohn’s disease and ulcerative colitis-inflammatory bowel diseases(IBDs).IBDs are complex and multifactorial disorders characterized by chronic and recurrent inflammation of the intestine,and the symptoms of IBDs may include abdominal pain,diarrhea,rectal bleeding,and weight loss.The P2X7 receptor has become a promising therapeutic target for IBDs,especially owing to its wide expression and,in the case of other purinergic receptors,in both human and model animal enteric cells.However,little is known about the actual involvement between the activation of the P2X7 receptor and the cascade of subsequent events and how all these activities associated with chemical signals interfere with the functionality of the affected or treated intestine.In this review,an integrated view is provided,correlating the structural organization of the ENS and the effects of IBDs,focusing on cellular constituents and how therapeutic approaches through the P2X7 receptor can assist in both protection from damage and tissue preservation.

P2X7 receptor as the regulator of T-cell function in intestinal barrier disruption

The intestinal mucosa is a highly compartmentalized structure that forms a directbarrier between the host intestine and the environment, and its dysfunction couldresult in a serious disease. As T cells, which are important components of themucosal immune system, interact with gut microbiota and maintain intestinalhomeostasis, they may be involved in the process of intestinal barrier dysfunction.P2X7 receptor (P2X7R), a member of the P2X receptors family, mediates the effectsof extracellular adenosine triphosphate and is expressed by most innate or adaptiveimmune cells, including T cells. Current evidence has demonstrated thatP2X7R is involved in inflammation and mediates the survival and differentiationof T lymphocytes, indicating its potential role in the regulation of T cell function.In this review, we summarize the available research about the regulatory role andmechanism of P2X7R on the intestinal mucosa-derived T cells in the setting ofintestinal barrier dysfunction.

P2X7 receptor antagonist recovers ileum myenteric neurons after experimental ulcerative colitis

BACKGROUND The P2X7 receptor is expressed by enteric neurons and enteric glial cells.Studies have demonstrated that administration of a P2X7 receptor antagonist,brilliant blue G(BBG),prevents neuronal loss.AIM To report the effects of BBG in ileum enteric neurons immunoreactive(ir)following experimental ulcerative colitis in Rattus norvegicus albinus.METHODS 2,4,6-trinitrobenzene sulfonic acid(TNBS group,n=5)was injected into the distal colon.BBG(50 mg/kg,BBG group,n=5)or vehicle(sham group,n=5)was given subcutaneously 1 h after TNBS.The animals were euthanized after 24 h,and the ileum was removed.Immunohistochemistry was performed on the myenteric plexus to evaluate immunoreactivity for P2X7 receptor,neuronal nitric oxide synthase(nNOS),choline acetyltransferase(ChAT),HuC/D and glial fibrillary acidic protein.RESULTS The numbers of nNOS-,ChAT-,HuC/D-ir neurons and glial fibrillary acidic protein-ir glial cells were decreased in the TNBS group and recovered in the BBG group.The neuronal profile area(μm^2)demonstrated that nNOS-ir neurons decreased in the TNBS group and recovered in the BBG group.There were no differences in the profile areas of ChAT-and HuC/D-ir neurons.CONCLUSION Our data conclude that ileum myenteric neurons and glial cells were affected by ulcerative colitis and that treatment with BBG had a neuroprotective effect.Thus,these results demonstrate that the P2X7 receptor may be an important target in therapeutic strategies.

P2X7 receptor inhibitor suppressed extracellular ATP/LPS-primed human hepatic stellate cells activation via downregulating NLRP3 inflammasome

OBJECTIVE To investigate the effect of P2X7receptor(P2X7r)inhibition,using a specific inhibitor(A438079)to prevent the development of liver fibrosis on human hepatic stellate cells,LX-2.METHODS The supernatant from lipopolysaccharide(LPS)-stimulated RAW264.7 mouse macrophages was supplemented to LX-2 cells for 24 h.LX-2cells were primed with LPS for 4h and subsequently stimulated for 30 min with 3mmol·L-1 of adenosine 5′-triphosphate(ATP).A438079(10μmol·L-1)was supplemented to LX-2 cells 10 min prior to ATP.RESULTS Directly treated with LPS on LX-2 cells,mRNA expressions of IL-1β,IL-18 and IL-6 were increased,as well as P2X7 r.And caspase-1,ASC and NLRP3 mRNA expressions were increased with LPS stimulation.LPS stimulation also increasedα-SMA and collagenⅠ mRNA expressions.Interestingly treatment of LX-2cells with mediums from LPS-primed RAW264.7mouse macrophages exhibited greater increase of mRNA expressions of above genes than those in LX-2directly treated with LPS.Pretreatment of directly or indirectly LPS-stimulated LX-2 cells with A438079 both suppressed IL-1βmRNA expression.In addition treatment of LPS-primed LX-2 cells with 3mmol·L-1 ATP induced the significant increase of IL-1β,IL-6,caspase-1,pannexin-1,α-SMA and collagenⅠ mRNA expression,the increasing ofα-SMA protein expression and cleavage of IL-1β.These events were significantly suppressed by pretreatment with P2X7 rantagonist A438079.P2X7 rblockade also significantly reduced the protein expression ofα-SMA.CONCLUSION Our results suggest that the involvement of the P2X7r-NLRP3 inflammasome pathway in the secretion of IL-1βfrom extracellular ATP/LPS-stimulated human hepatic stellate cells.This study demonstrated that repression of the P2X7 rrepresents a novel potential therapeutic approach to control liver fibrosis.

P2X7 receptor blockade decreases inflammation,apoptosis,and enteric neuron loss during Clostridioides difficile toxin A-induced ileitis in mice

Clostridioides difficile(C.difficile)is the most common pathogen causing health care-associated infections.C.difficile TcdA and TcdB have been shown to activate enteric neurons;however,what population of these cells is more profoundly influenced and the mechanism underlying these effects remain unknown.AIM To characterize a specific population of TcdA-affected myenteric neurons and investigate the role of the P2X7 receptor in TcdA-induced ileal inflammation,cell death,and the changes in the enteric nervous system in mice.METHODS Swiss mice were used to model TcdA-induced ileitis in ileal loops exposed to TcdA(50μg/Loop)for 4 h.To investigate the role of the P2X7 receptor,Brilliant Blue G(50 mg/kg,i.p.),which is a nonspecific P2X7 receptor antagonist,or A438079(0.7μg/mouse,i.p.),which is a competitive P2X7 receptor antagonist,were injected one hour prior to TcdA challenge.Ileal samples were collected to analyze the expression of the P2X7 receptor(by quantitative real-time polymerase chain reaction and immunohistochemistry),the population of myenteric enteric neurons(immunofluorescence),histological damage,intestinal inflammation,cell death(terminal deoxynucleotidyltransferasemediated dUTP-biotin nick end labeling),neuronal loss,and S100B synthesis(immunohistochemistry).RESULTS TcdA upregulated(P<0.05)the expression of the P2X7 receptor gene in the ileal tissues,increasing the level of this receptor in myenteric neurons compared to that in control mice.Comparison with the control mice indicated that TcdA promoted(P<0.05)the loss of myenteric calretinin+(Calr)and choline acetyltransferase+neurons and increased the number of nitrergic+and Calr+neurons expressing the P2X7 receptor.Blockade of the P2X7 receptor decreased TcdAinduced intestinal damage,cytokine release[interleukin(IL)-1β,IL-6,IL-8,and tumor necrosis factor-α],cell death,enteric neuron loss,and S100B synthesis in the mouse ileum.CONCLUSION Our findings demonstrated that TcdA induced the upregulation of the P2X7 receptor,which promoted enteric neuron loss,S100B synthesis,tissue damage,inflammation,and cell death in the mouse ileum.These findings contribute to the future directions in understanding the mechanism involved in intestinal dysfunction reported in patients after C.difficile infection.

Targeting the P2X7 receptor in microglial cells to prevent brain inflammation

Microglial cells are the key innate immune cells in the brain and they are crucial in maintaining brain parenchyma homeostasis.Under physiological conditions,microglial cells assume a ramified morphology with a small cell body and an extensive network of fine processes,which secrete neurotrophic factors and patrol the surroundings in search for pathogens and eliminate cellular debris via phagocytosis.Microglial cells express a repertoire of pattern recognition receptors(PRRs)that enable them to detect diverse danger-associated molecular patterns(DAMPs)released from damaged cells or cells under stress,or pathogen-associated molecular patterns generated by pathogens during infection.

P2X7 Receptor Mediated Growth-Inhibitory Effect in KG1a Cell Line

OBJECTIVE This study was conducted to investigate ATP- induced growth inhibition in human leukemic cells KG1a. METHODS ATP inhibited cell growth was analyzed by MTS assay. Externalization of phosphatidylserine could be detected by Annexin-V-FITC apoptosis staining after activation of the P2X7 receptor. P2X7 mediated pore formation was detected in KGla cells by Yo-Pro-1 uptake assay. RESULTS ATP inhibited cell growth in a dose-dependent manner. The cytotoxic effect could be blocked by P2X7 antagonists, oxidized ATP （oATP） and KN62. Externalization of phosphatidylserine could be detected in a time-dependent manner. P2X7 mediated pore formation could be detected in KG1a cells. These effects could not be observed in P2X7 null Ramos cells. CONCLUSION The results and our previously reports that mRNA, protein expression and calcium response of the P2X7 receptor in KGla cells, suggested that extracellular ATP effectively induces growth inhibition through apoptosis in KGla cells by activation of P2X7 receptor, and that may be mediated by extracellular Ca^2＋ in ux and pore formation.

Hydrogen sulfide intervention in focal cerebral ischemia/reperfusion injury in rats

The present study aimed to explore the mechanism underlying the protective effects of hydrogen sulfide against neuronal damage caused by cerebral ischemia/reperfusion. We established the middle cerebral artery occlusion model in rats via the suture method. Ten minutes after middle cerebral artery occlusion, the animals were intraperitoneally injected with hydrogen sulfide donor compound sodium hydrosulfide. Immunofluorescence revealed that the immunoreactivity of P2X7 in the cerebral cortex and hippocampal CA1 region in rats with cerebral ischemia/reperfusion injury decreased with hydrogen sulfide treatment. Furthermore, treatment of these rats with hydrogen sulfide significantly lowered mortality, the Longa neurological deficit scores, and infarct volume. These results indicate that hydrogen sulfide may be protective in rats with local cerebral ischemia/reperfusion injury by down-regulating the expression of P2X7 receptors.

Inhibition of inflammatory mediator release from microglia can treat ischemic/hypoxic brain injury

Interleukin-1α and interleukin-1β aggravate neuronal injury by mediating the inf1αmmatory reaction following ischemic/hypoxic brain injury. It remains unclear whether interleukin-1α and interleukin-1β are released by microglia or astrocytes. This study prepared hippocampal slices that were subsequently subjected to oxygen and glucose deprivation. Hematoxylin-eosin staining verified that neurons exhibited hypoxic changes. Results of enzyme-linked immunosorbent assay found that interleukin-1α and interleukin-1β participated in this hypoxic process. Moreover, when hypoxic injury occurred in the hippocampus, the release of interleukin-1α and interleukin-1β was mediated by the P2X4 receptor and P2X7 receptor. Immunofluorescence staining revealed that during ischemia/hypoxia, the P2X4 receptor, P2X7 receptor, interleukin-1α and interleukin-1β expression was detectable in rat hippocampal microglia, but only P2X4 receptor and P2X7 receptor expression was detected in astrocytes. Results suggested that the P2X4 receptor and P2X7 receptor, respectively, mediated interleukin-1α and interleukin-1β released by microglia, resulting in hippocampal ischemic/hypoxic injury. Astrocytes were activated, but did not synthesize or release interleukin-1α and interleukin-1β.

Isoflurane-induced neuronal apoptosis in developing hippocampal neurons

We hypothesized that the P2X7 receptor may be the target of isoflurane, so we investigated the roles of the P2X7 receptor and inositol triphosphate receptor in calcium overload and neuronal apoptosis induced by isoflurane in cultured embryonic rat hippocampal neurons. Results showed that isoflurane induced widespread neuronal apoptosis and significantly increased cytoplasmic Ca^2＋ Blockade of P2X7 receptors or removal of extracellular Ca^2＋ combined with blockade of inositol triphosphate receptors completely inhibited apoptosis or increase in cytoplasmic Ca^2＋. Removal of extracellular Ca^2＋ or blockade of inositol triphosphate receptor alone could partly inhibit these effects of isoflurane. Isoflurane could directly activate P2X7-gated channels and induce inward currents, but did not affect the expression of P2X7 receptor protein in neurons. These findings indicate that the mechanism by which isoflurane induced neuronal apoptosis in rat developing brain was mediated by intracellular calcium overload, which was caused by P2X7 receptor mediated calcium influx and inositol triphosphate receptor mediated calcium release.

Brilliant blue G attenuates lipopolysaccharide-mediated microglial activation and inflammation

Previous studies have confirmed that oxidized adenosine triphosphate, a P2X7 receptor antagonist, attenuates lipopolysaccharide-mediated microglial activation and inflammatory expression following neuronal damage in rat brain. NaCI and temperature may affect the potency of oxidized adenosine triphosphate. Brilliant blue G is a derivative of a widely used food additive and has little toxicity. This study explored the effects of brilliant blue G, a selective P2X7 receptor antagonist, on microglial activation and inflammation. Results demonstrated that brilliant blue G inhibited the release of cydooxygenase-2 and interleukin-6 in BV2 cells. Immunofluorescence displayed that brilliant blue G could suppress lipopolysaccharide-induced microglial activation. This study used RNA interference to block P2X7 receptor expression and found that small interfering RNA also suppressed the release of cyclooxygenase-2 and interleukin-6 in BV2 cells. These results suggested that downregulation of the P2X7 receptor by brilliant blue G was involved in the inhibition of microglial activation and inflammation.

Localization of P2X_7 Receptor Immunoreactivity in the Dorsal Root Ganglia of Guinea Pig

The P2X7 receptor mRNA and proteins in guinea-pig dorsal root ganglia （DRG） were studied by using RT-PCR and immunohistochemistry. The co-localization of P2X7 receptor with four cytochemical markers, the neurofilament protein NF200, S100, substance P and isolectin t34 （IB4） binding glyco-conjugates, were also examined. It was found that P2X7 receptor immunoreactivity （P2X7 R-IR） was present mostly in large-and medium-sized DRG neurons （62%±9% and 36%±6% respectively in all P2X7 R-IR neurons）. All the P2X7 R-IR neurons were also NF200 and S100 immunopositive. However, in a small number of NF200 or S100 immunopositive neurons no P2XTR-IR was detectable. All the IB4-positive or substance P-immunopositive neurons had no P2X7 R-IR. These results demonstrate that P2X7 receptors are expressed in a large subpopulation of DRG neurons and they may play a role in the transduction of specific peripheral sensory signals.

P2X7 Receptor Antagonism Attenuates the Intermittent Hypoxia-induced Spatial Deficits in a Murine Model of Sleep Apnea Via Inhibiting Neuroinflammation and Oxidative Stress

Background：The 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.Methods：Eight-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 Westem blotting.The expressions of tumor necrosis factor α,interleukin 1 β （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.Results：The 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.Conclusions：The 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.

P2X_7 receptors in cerebral ischemia

Cerebral ischemia is one of the most common diseases resulting in death and disability in aged people. It leads immediately to rapid energy failure, ATP depletion, and ionic imbalance, which increase extracellular ATP levels and accordingly activate P2X7 receptors. These receptors are ATP-gated cation channels and widely distributed in nerve cells, especially in the immunocompetent cells of the brain. Currently, interest in the roles of P2Xz receptors in ischemic brain injury is growing. In this review, we discuss recent research progress on the actions of P2X7 receptors, their possible mechanisms in cerebral ischemia, and the potential therapeutic value of P2X7 receptor antagonists which may provide a new target both for clinical and for research purposes.

P2X7 Receptor in Alcoholic Steatohepatitis and Alcoholic Liver Fibrosis

Alcoholic liver disease is one of the most common chronic liver diseases in the world.It is a liver disease caused by prolonged heavy drinking and its main clinical features are nausea,vomiting,enlargement of the liver,and jaundice.Recent studies suggest that Kupffer cell-mediated inflam-matory response is a core driver in the development of alco-holic steatohepatitis and alcoholic liver fibrosis.As a danger signal,extracellular ATP activates the assembly of NLPR3 inflammasome by acting on purine P2X7 receptor,the ac-tivated NLRP3 inflammasome prompts ASC to cleave pro-cCaspase-1 into active caspase-1in KCs.Active caspase-1 promotes the conversion of pro-IL-1βto IL-1β,which fur-ther enhances the inflammatory response.Here,we briefly review the role of the P2X7R-NLRP3 inflammasome axis in the pathogenesis of alcoholic liver disease and the evolution of alcoholic steatohepatitis and alcoholic liver fibrosis.Reg-ulation of the inflammasome axis of P2X7R-NLRP3 may be a new approach for the treatment of alcoholic liver disease.

SpinalP2X7R contributes to streptozotocin-induced mechanical allodynia in mice

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.