H3 relaxin inhibits the collagen synthesis via ROS‐ and P2X7R‐mediated NLRP3 inflammasome activation in cardiac fibroblasts under high glucose

Excessive production of reactive oxygen species (ROS) and P2X7R activation induced by high glucose increases NLRP3 inflammasome activation, which contributes to the pathogenesis of diabetic cardiomyopathy. Although H3 relaxin has been shown to inhibit cardiac fibrosis induced by isoproterenol, the mechanism has not been well studied. Here, we demonstrated that high glucose (HG) induced the collagen synthesis by activation of the NLRP3 inflammasome, leading to caspase‐1 activation, interleukin‐1β (IL‐1β) and IL‐18 secretion in neonatal rat cardiac fibroblasts. Moreover, we used a high‐glucose model with neonatal rat cardiac fibroblasts and showed that the activation of ROS and P2X7R was augmented and that ROS‐ and P2X7R‐mediated NLRP3 inflammasome activation was critical for the collagen synthesis. Inhibition of ROS and P2X7R decreased NLRP3 inflammasome‐mediated collagen synthesis, similar to the effects of H3 relaxin. Furthermore, H3 relaxin reduced the collagen synthesis via ROS‐ and P2X7R‐mediated NLRP3 inflammasome activation in response to HG. These results provide a mechanism by which H3 relaxin alleviates NLRP3 inflammasome‐mediated collagen synthesis through the inhibition of ROS and P2X7R under HG conditions and suggest that H3 relaxin represents a potential drug for alleviating cardiac fibrosis in diabetic cardiomyopathy.     

Microglial Mincle receptor in the PVN contributes to sympathetic hyperactivity in acute myocardial infarction rat

Malignant ventricular arrhythmias (VAs) following myocardial infarction (MI) is a lethal complication resulting from sympathetic nerve hyperactivity. Numerous evidence have shown that inflammation within the paraventricular nucleus (PVN) participates in sympathetic hyperactivity. Our aim was to explore the role of Macrophage‐inducible C‐type lectin (Mincle) within the PVN in augmenting sympathetic activity following MI,and whether NOD‐like receptor family pyrin domain‐containing 3 (NLRP3) inflammasome/IL‐1β axis is involved in this activity. MI was induced by coronary artery ligation. Mincle expression localized in microglia within the PVN was markedly increased at 24 hours post‐MI together with sympathetic hyperactivity, as indicated by measurement of the renal sympathetic nerve activity (RSNA) and norepinephrine (NE) concentration. Mincle‐specific siRNA was administrated locally to the PVN, which consequently decreased microglial activation and sympathetic nerve activity. The MI rats exhibited a higher arrhythmia score after programmed electric stimulation than that treated with Mincle siRNA, suggesting that the inhibition of Mincle attenuated foetal ventricular arrhythmias post‐MI. The underlying mechanism of Mincle in sympathetic hyperactivity was investigated in lipopolysaccharide (LPS)‐primed naïve rats. Recombinant Sin3A‐associated protein 130kD (rSAP130), an endogenous ligand for Mincle, induced high levels of NLRP3 and mature IL‐1β protein. PVN‐targeted injection of NLRP3 siRNA or IL‐1β antagonist gevokizumab attenuated sympathetic hyperactivity. Together, the data indicated that the knockdown of Mincle in microglia within the PVN prevents VAs by attenuating sympathetic hyperactivity and ventricular susceptibility, in part by inhibiting its downstream NLRP3/IL‐1β axis following MI. Therapeutic interventions targeting Mincle signalling pathway could constitute a novel approach for preventing infarction injury.     

P2X7 nucleotide receptors mediate caspase-8/9/3-dependent apoptosis in rat primary cortical neurons

Apoptosis is a major cause of cell death in the nervous system. It plays a role in embryonic and early postnatal brain development and contributes to the pathology of neurodegenerative diseases. Here, we report that activation of the P2X₇ nucleotide receptor (P2X₇R) in rat primary cortical neurons (rPCNs) causes biochemical (i.e., caspase activation) and morphological (i.e., nuclear condensation and DNA fragmentation) changes characteristic of apoptotic cell death. Caspase-3 activation and DNA fragmentation in rPCNs induced by the P2X₇R agonist BzATP were inhibited by the P2X₇R antagonist oxidized ATP (oATP) or by pre-treatment of cells with P2X₇R antisense oligonucleotide indicating a direct involvement of the P2X₇R in nucleotide-induced neuronal cell death. Moreover, Z-DEVD-FMK, a specific and irreversible cell permeable inhibitor of caspase-3, prevented BzATP-induced apoptosis in rPCNs. In addition, a specific caspase-8 inhibitor, Ac-IETD-CHO, significantly attenuated BzATP-induced caspase-9 and caspase-3 activation, suggesting that P2X₇R-mediated apoptosis in rPCNs occurs primarily through an intrinsic caspase-8/9/3 activation pathway. BzATP also induced the activation of C-jun N-terminal kinase 1 (JNK1) and extracellular signal-regulated kinases (ERK1/2) in rPCNs, and pharmacological inhibition of either JNK1 or ERK1/2 significantly reduced caspase activation by BzATP. Taken together, these data indicate that extracellular nucleotides mediate neuronal apoptosis through activation of P2X₇Rs and their downstream signaling pathways involving JNK1, ERK and caspases 8/9/3.     

Up‐regulation and activation of the P2Y2 nucleotide receptor mediate neurite extension in IL‐1β‐treated mouse primary cortical neurons

The pro‐inflammatory cytokine interleukin‐1β (IL‐1β), whose levels are elevated in the brain in Alzheimer's and other neurodegenerative diseases, has been shown to have both detrimental and beneficial effects on disease progression. In this article, we demonstrate that incubation of mouse primary cortical neurons (mPCNs) with IL‐1β increases the expression of the P2Y₂ nucleotide receptor (P2Y₂R) and that activation of the up‐regulated receptor with UTP, a relatively selective agonist of the P2Y₂R, increases neurite outgrowth. Consistent with the accepted role of cofilin in the regulation of neurite extension, results indicate that incubation of IL‐1β‐treated mPCNs with UTP increases the phosphorylation of cofilin, a response absent in PCNs isolated from P2Y₂R^?/? mice. Other findings indicate that function‐blocking anti‐α_vβ_3/5 integrin antibodies prevent UTP‐induced cofilin activation in IL‐1β‐treated mPCNs, suggesting that established P2Y₂R/α_vβ_3/5 interactions that promote G₁₂‐dependent Rho activation lead to cofilin phosphorylation involved in neurite extension. Cofilin phosphorylation induced by UTP in IL‐1β‐treated mPCNs is also decreased by inhibitors of Ca²⁺/calmodulin‐dependent protein kinase II (CaMKII), suggesting a role for P2Y₂R‐mediated and G_q‐dependent calcium mobilization in neurite outgrowth. Taken together, these studies indicate that up‐regulation of P2Y₂Rs in mPCNs under pro‐inflammatory conditions can promote cofilin‐dependent neurite outgrowth, a neuroprotective response that may be a novel pharmacological target in the treatment of neurodegenerative diseases.     

Dynamics of macrophage polarization reveal new mechanism to inhibit IL-1β release through pyrophosphates

In acute inflammation, extracellular ATP activates P2X₇ ion channel receptors (P2X₇R) on M1 polarized macrophages to release pro-inflammatory IL-1β through activation of the caspase-1/nucleotide-binding domain and leucine-rich repeat receptor containing pyrin domain 3 (NLRP3) inflammasome. In contrast, M2 polarized macrophages are critical to the resolution of inflammation but neither actions of P2X₇R on these macrophages nor mechanisms by which macrophages switch from pro-inflammatory to anti-inflammatory phenotypes are known. Here, we investigated extracellular ATP signalling over a dynamic macrophage polarity gradient from M1 through M2 phenotypes. In macrophages polarized towards, but not at, M2 phenotype, in which intracellular IL-1β remains high and the inflammasome is intact, P2X₇R activation selectively uncouples to the NLRP3-inflammasome activation but not to upstream ion channel activation. In these intermediate M1/M2 polarized macrophages, extracellular ATP now acts through its pyrophosphate chains, independently of other purine receptors, to inhibit IL-1β release by other stimuli through two independent mechanisms: inhibition of ROS production and trapping of the inflammasome complex through intracellular clustering of actin filaments.     

The effects of NONRATT021972 lncRNA siRNA on PC12 neuronal injury mediated by P2X<Subscript>7</Subscript> receptor after exposure to oxygen-glucose deprivation

Adenosine triphosphate (ATP) participates in signal transmission by acting on P2X receptors, and the P2X₇ receptor is involved in the pathophysiological changes of ischemic injury. The PC12 cell line is a popular model system to study sympathetic neuronal function. Long noncoding RNAs (lncRNAs) are highly expressed in the nervous system and serve as regulatory RNAs. In this study, the effects of NONRATT021972 lncRNA siRNA on P2X₇-mediated PC12 neuronal injury after exposure to oxygen-glucose deprivation (OGD) were investigated. Our results showed that the viability of PC12 cells cultured with OGD or the P2X₇ agonist BzATP was significantly decreased. Treatment with NONRATT021972 siRNA reversed the decreased viability of PC12 cells under OGD conditions. The upregulated P2X₇ mRNA and protein levels in PC12 cells under OGD conditions or BzATP treatment were significantly decreased when pretreated with NONRATT021972 siRNA. Moreover, NONRATT021972 siRNA treatment effectively suppressed the increase in [Ca²⁺]_i induced by OGD or P2X₇ agonists (ATP or BzATP) in PC12 cells. Therefore, treatment with NONRATT021972 siRNA may decrease sympathetic neuronal injury induced by ischemia.     

Amyloid β induces NLRP3 inflammasome activation in retinal pigment epithelial cells via NADPH oxidase‐ and mitochondria‐dependent ROS production

Amyloid β (Aβ)‐induced chronic inflammation is believed to be a key pathogenic process in early‐stage age‐related macular degeneration (AMD). Nucleotide oligomerization domain (NOD)‐like receptor family, pyrin domain containing 3 (NLRP3) inflammasome activation triggered by Aβ is responsible for retinal pigment epithelium (RPE) dysfunction in the onset of AMD; however, the detailed molecular mechanism remains unclear. In this study, we investigated the involvement of NADPH oxidase‐ and mitochondria‐derived reactive oxygen species (ROS) in the process of Aβ_1–40‐induced NLRP3 inflammasome activation in LPS‐primed ARPE‐19 cells. The results showed that Aβ_1–40 could induce excessive ROS generation, MAPK/NF‐κB signaling activation and subsequently NLRP3 inflammasome activation in LPS‐primed ARPE‐19 cells. Furthermore, the inductive effect of Aβ_1–40 on NLRP3 inflammasome activation was mediated in a manner dependent on NADPH oxidase‐ and mitochondria‐derived ROS. Our findings may provide a novel insight into the molecular mechanism by which Aβ contributes to the early‐stage AMD.     

P2X7 receptor regulation of non‐classical secretion from immune effector cells

P2X7 receptors (P2X7R) are extracellular ATP‐gated ion channels expressed in the immune effector cells that carry out critical protective responses during the early phases of microbial infection or acute tissue trauma. P2X7R‐positive cells include monocytes, macrophages, dendritic cells and T cells. Given its presence in all host and pathogen cell types, ATP can be readily released into extracellular compartments at local sites of tissue damage and microbial invasion. Thus, extracellular ATP and its target receptors on host effector cells can be considered as additional elements of the innate immune system. In this regard, stimulation of P2X7R rapidly triggers a key step of the inflammatory response: induction of NLRP3/caspase‐1 inflammasome signalling complexes that drive the proteolytic maturation and secretion of the proinflammatory cytokines interleukin‐1β (IL‐1β) and interleukin‐18 (IL‐18). IL‐1β (and IL‐18) lacks a signal sequence for compartmentation within the Golgi and classical secretory vesicles and the proIL‐1β precursor accumulates within the cytosol following translation on free ribosomes. Thus, ATP‐induced accumulation of the mature IL‐1β cytokine within extracellular compartments requires non‐classical mechanisms of export from the cytosolic compartment. Five proposed mechanisms include: (i) exocytosis of secretory lysosomes that accumulate cytosolic IL‐1β via undefined protein transporters; (ii) release of membrane‐delimited microvesicles derived from plasma membrane blebs formed by evaginationsof the surface membrane that entrap cytosolic IL‐β; (iii) release of membrane‐delimited exosomes secondary to the exocytosis of multivesicular bodies formed by invaginations of recycling endosomes that entrap cytosolic IL‐β; (iv) exocytosis of autophagosomes or autophagolysosomes that accumulate cytosolic IL‐1β via entrapment during formation of the initial autophagic isolation membrane or omegasome and (v) direct release of cytosolic IL‐1β secondary to regulated cell death by pyroptosis or necroptosis. These mechanisms are not mutually exclusive and may represent engagement of parallel or intersecting membrane trafficking responses to P2X7R activation.     

P2X<Subscript>7</Subscript>R modulation of visually evoked synaptic responses in the retina

P2X₇Rs are distributed throughout all layers of the retina, and thus, their localisation on various cell types puts into question their specific site(s) of action. Using a dark-adapted, ex vivo mouse retinal whole mount preparation, the present study aimed to characterise the effect of P2X₇R activation on light-evoked, excitatory RGC ON-field excitatory post-synaptic potentials (fEPSPs) and on outer retinal electroretinogram (ERG) responses under comparable conditions. The pharmacologically isolated NMDA receptor-mediated RGC ON-fEPSP was reduced in the presence of BzATP, an effect which was significantly attenuated by A438079 and other selective P2X₇R antagonists A804598 or AF27139. In physiological Krebs medium, BzATP induced a significant potentiation of the ERG a-wave, with a concomitant reduction in the b-wave and the power of the oscillatory potentials. Conversely, in the pharmacologically modified Mg²⁺-free perfusate, BzATP reduced both the a-wave and b-wave. The effects of BzATP on the ERG components were suppressed by A438079. A role for P2X₇R function in visual processing in both the inner and outer retina under physiological conditions remains controversial. The ON-fEPSP was significantly reduced in the presence of A804598 but not by A438079 or AF27139. Furthermore, A438079 did not have any effect on the ERG components in physiological Krebs but potentiated and reduced the a-wave and b-wave, respectively, when applied to the pharmacologically modified medium. Therefore, activation of P2X₇Rs affects the function in the retinal ON pathway. The presence of a high concentration of extracellular ATP would most likely contribute to the modulation of visual transmission in the retina in the pathophysiological microenvironment.     

Gypenosides improve diabetic cardiomyopathy by inhibiting ROS‐mediated NLRP3 inflammasome activation

NLRP3 inflammasome activation plays an important role in diabetic cardiomyopathy (DCM), which may relate to excessive production of reactive oxygen species (ROS). Gypenosides (Gps), the major ingredients of Gynostemma pentaphylla (Thunb.) Makino, have exerted the properties of anti‐hyperglycaemia and anti‐inflammation, but whether Gps improve myocardial damage and the mechanism remains unclear. Here, we found that high glucose (HG) induced myocardial damage by activating the NLRP3 inflammasome and then promoting IL‐1β and IL‐18 secretion in H9C2 cells and NRVMs. Meanwhile, HG elevated the production of ROS, which was vital to NLRP3 inflammasome activation. Moreover, the ROS activated the NLRP3 inflammasome mainly by cytochrome c influx into the cytoplasm and binding to NLRP3. Inhibition of ROS and cytochrome c dramatically down‐regulated NLRP3 inflammasome activation and improved the cardiomyocyte damage induced by HG, which was also detected in cells treated by Gps. Furthermore, Gps also reduced the levels of the C‐reactive proteins (CRPs), IL‐1β and IL‐18, inhibited NLRP3 inflammasome activation and consequently improved myocardial damage in vivo. These findings provide a mechanism that ROS induced by HG activates the NLRP3 inflammasome by cytochrome c binding to NLRP3 and that Gps may be potential and effective drugs for DCM via the inhibition of ROS‐mediated NLRP3 inflammasome activation.     

ATP‐dependent activation of an inflammasome in primary gingival epithelial cells infected by Porphyromonas gingivalis

Production of IL‐1β typically requires two‐separate signals. The first signal, from a pathogen‐associated molecular pattern, promotes intracellular production of immature cytokine. The second signal, derived from a danger signal such as extracellular ATP, results in assembly of an inflammasome, activation of caspase‐1 and secretion of mature cytokine. The inflammasome component, Nalp3, plays a non‐redundant role in caspase‐1 activation in response to ATP binding to P2X₇ in macrophages. Gingival epithelial cells (GECs) are an important component of the innate‐immune response to periodontal bacteria. We had shown that GECs express a functional P2X₇ receptor, but the ability of GECs to secrete IL‐1β during infection remained unknown. We find that GECs express a functional Nalp3 inflammasome. Treatment of GECs with LPS or infection with the periodontal pathogen, Porphyromonas gingivalis, induced expression of the il‐1β gene and intracellular accumulation of IL‐1β protein. However, IL‐1β was not secreted unless LPS‐treated or infected cells were subsequently stimulated with ATP. Conversely, caspase‐1 is activated in GECs following ATP treatment but not P. gingivalis infection. Furthermore, depletion of Nalp3 by siRNA abrogated the ability of ATP to induce IL‐1β secretion in infected cells. The Nalp3 inflammasome is therefore likely to be an important mediator of the inflammatory response in gingival epithelium.     

Soluble uric acid induces myocardial damage through activating the NLRP3 inflammasome

Uric acid crystal is known to activate the NLRP3 inflammasome and to cause tissue damages, which can result in many diseases, such as gout, chronic renal injury and myocardial damage. Meanwhile, soluble uric acid (sUA), before forming crystals, is also related to these diseases. This study was carried out to investigate whether sUA could also activate NLRP3 inflammasome in cardiomyocytes and to analyse the mechanisms. The cardiomyocyte activity was monitored, along with the levels of mature IL‐1β and caspase‐1 from H9c2 cells following sUA stimulus. We found that sUA was able to activate NLRP3 inflammasome, which was responsible for H9c2 cell apoptosis induced by sUA. By elevating TLR6 levels and then activating NF‐κB/p65 signal pathway, sUA promoted NLRP3, pro‐caspase 1 and pro‐IL‐1β production and provided the first signal of NLRP3 inflammasome activation. Meanwhile, ROS production regulated by UCP2 levels also contributed to NLRP3 inflammasome assembly and subsequent caspase 1 activation and mature IL‐1β secretion. In addition, the tlr6 knockdown rats suffering from hyperuricemia showed the lower level of IL‐1β and an ameliorative cardiac function. These findings suggest that sUA activates NLRP3 inflammasome in cardiomyocytes and they may provide one therapeutic strategy for myocardial damage induced by sUA.     

Plasticizer DBP Activates NLRP3 Inflammasome through the P2X7 Receptor in HepG2 and L02 Cells

Ditubyl phthalate (DBP), one of the most widely used plasticizers, can migrate out to contaminate our bodies and environment. A number of studies have showed that DBP is closely related to liver pathological changes and diseases. Inflammasomes are multiprotein complexes composed of procaspase and pattern recognition receptors such as Nucleotide oligomerization domain (NOD) like receptor family, pyrin domain containing 3 (NLRP3). Activation of NLRP3 inflammasome is implicated in the pathogeneses of liver damage. The aim of this study was to determine the effects of DBP on NLRP3 inflammasome. We found that DBP triggered the activation of NLRP3 inflammasome in hepatocyte cell lines. By using Ca‐074‐Me, N‐acetylcysteine and KN‐62, we observed that the P2X₇ receptor participated in the DBP‐induced activation of NLRP3 inflammasome. DBP could also trigger the ATP release. In conclusion, we demonstrated that DBP is one of the activator of NLRP3 inflammasome and may play an important role in liver damage.     

Naoxintong attenuates Ischaemia/reperfusion Injury through inhibiting NLRP3 inflammasome activation

Naoxintong (NXT) is a Chinese Materia Medica standardized product extracted from 16 various kinds of Chinese traditional herbal medicines including Salvia miltiorrhiza, Angelica sinensis, Astragali Radix. Naoxintong is clinically effective in treating ischaemia heart disease. Nucleotide‐binding oligomerization domain‐Like Receptor with a Pyrin domain 3 (NLRP3) inflammasome has been critically involved in myocardial ischaemia/reperfusion (I/R) injury. Here, we have been suggested that NXT might attenuate myocardial I/R injury via suppression of NLRP3 inflammasome activation. Male C57BL6 mice were subjected to myocardial I/R injury via 45 min. coronary ligation and release for the indicated times. Naoxintong (0.7 g/kg/day) and PBS were orally administrated for 2 weeks before surgery. Cardiac function assessed by echocardiography was significantly improved in the NXT group compared to PBS group at day 2 after myocardial I/R. NLRP3 inflammasome activation is crucially involved in the initial inflammatory response after myocardial I/R injury, leading to cleaved caspase‐1, mature interleukin (IL)‐1β production, accompanying by macrophage and neutrophil infiltration. The cardioprotective effect of NXT was associated with a diminished NLRP3 inflammasome activation, decreased pro‐inflammatory macrophage (M1 macrophages) and neutrophil infiltration after myocardial I/R injury. In addition, serum levels of IL‐1β, indicators of NLRP3 inflammasome activation, were also significantly suppressed in the NXT treated group after I/R injury. Naoxintong exerts cardioprotive effects at least partly by suppression of NLRP3 inflammasome activation in this I/R injury model.     

Advanced glycation end products regulate anabolic and catabolic activities via NLRP3‐inflammasome activation in human nucleus pulposus cells

Intervertebral disc degeneration is widely recognized as a cause of lower back pain, neurological dysfunction and other musculoskeletal disorders. The major inflammatory cytokine IL‐1β is associated with intervertebral disc degeneration; however, the molecular mechanisms that drive IL‐1β production in the intervertebral disc, especially in nucleus pulposus (NP) cells, are unknown. In some tissues, advanced glycation end products (AGEs), which accumulate in NP tissues and promote its degeneration, increase oxidative stress and IL‐1β secretion, resulting in disorders, such as obesity, diabetes mellitus and ageing. It remains unclear whether AGEs exhibit similar effects in NP cells. In this study, we observed significant activation of the NLRP3 inflammasome in NP tissues obtained from patients with degenerative disc disease compared to that with idiopathic scoliosis according to results detected by Western blot and immunofluorescence. Using NP cells established from healthy tissues, our in vitro study revealed that AGEs induced an inflammatory response in NP cells and a degenerative phenotype in a NLRP3‐inflammasome‐dependent manner related to the receptor for AGEs (RAGE)/NF‐κB pathway and mitochondrial damage induced by mitochondrial reactive oxygen species (mtROS) generation, mitochondrial permeability transition pore (mPTP) activation and calcium mobilization. Among these signals, both RAGE and mitochondrial damage primed NLRP3 and pro‐IL‐1β activation as upstream signals of NF‐κB activity, whereas mitochondrial damage was critical for the assembly of inflammasome components. These results revealed that accumulation of AGEs in NP tissue may initiate inflammation‐related degeneration of the intervertebral disc via activation of the NLRP3 inflammasome.     

Endothelial P2X7 receptors’ expression is reduced by schistosomiasis

Endothelial cells control vascular tone, permeability and leukocyte transmigration and are modulated by pro-inflammatory mediators. Schistosomiasis is an intravascular disease associated with inflammation, therefore altering endothelial cells’ phenotype. Purinergic P2X7 receptors (P2X7R) play an important role in inflammation; however, the impact of the disease upon endothelial P2X7R function or expression has not been explored. Using ethidium bromide uptake to investigate P2X7R function, we observed that the effects of ATP (3 mM) and the P2X7R agonist 3′-O-(4-benzoyl)-ATP (BzATP) were smaller in mesenteric endothelial cells from the Schistosoma mansoni-infected group than in the control group. In the control group, BzATP induced endothelial nitric oxide production, which was blocked by the P2X7R antagonists KN-62 and A740003. However, in the infected group, we observed a reduced effect of BzATP and no effect of both P2X7R antagonists, suggesting a downregulation of endothelial P2X7R in schistosomiasis. We observed similar results in both infected and P2X7R^−/− groups, which were also comparable to data obtained with KN-62- or A740004-treated control cells. Data from Western blot and immunocytochemistry assays confirmed the reduced expression of P2X7R in the infected group. In conclusion, our data show a downregulation of P2X7R in schistosomiasis infection, which likely limits the infection-related endothelial damage.     

Long noncoding NONRATT021972 siRNA normalized abnormal sympathetic activity mediated by the upregulation of P2X<Subscript>7</Subscript> receptor in superior cervical ganglia after myocardial ischemia

Previous studies showed that the upregulation of the P2X₇ receptor in cervical sympathetic ganglia was involved in myocardial ischemic (MI) injury. The dysregulated expression of long noncoding RNAs (lncRNAs) participates in the onset and progression of many pathological conditions. The aim of this study was to investigate the effects of a small interfering RNA (siRNA) against the NONRATT021972 lncRNA on the abnormal changes of cardiac function mediated by the up-regulation of the P2X₇ receptor in the superior cervical ganglia (SCG) after myocardial ischemia. When the MI rats were treated with NONRATT021972 siRNA, their increased systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR), low-frequency (LF) power, and LF/HF ratio were reduced to normal levels. However, the decreased high-frequency (HF) power was increased. GAP43 and tyrosine hydroxylase (TH) are markers of nerve sprouting and sympathetic nerve fibers, respectively. We found that the TH/GAP43 value was significantly increased in the MI group. However, it was reduced after the MI rats were treated with NONRATT021972 siRNA. The serum norepinephrine (NE) and epinephrine (EPI) concentrations were decreased in the MI rats that were treated with NONRATT021972 siRNA. Meanwhile, the increased P2X₇ mRNA and protein levels and the increased p-ERK1/2 expression in the SCG were also reduced. NONRATT021972 siRNA treatment inhibited the P2X₇ agonist BzATP-activated currents in HEK293 cells transfected with pEGFP-P2X₇. Our findings suggest that NONRATT021972 siRNA could decrease the upregulation of the P2X₇ receptor and improve the abnormal changes in cardiac function after myocardial ischemia.