ATP Release Research Articles

CD39 activities in the treated acupoints contributed to the analgesic mechanism of acupuncture on arthritis rats.

Our previous work had identified that at the acupuncture point (acupoint), acupuncture-induced ATP release was a pivotal event in the initiation of analgesia. We aimed to further elucidate the degradation of ATP by CD39. Acupuncture was administered at Zusanli acupoint on arthritis rats, and pain thresholds of the hindpaws were determined. Pharmacological tools or adeno-associated viruses were administered at the acupoints to interfere with targeting signals. Protein expression was determined with qRT-PCR, WB, or immunofluorescent labeling. Cultured keratinocytes, HaCaT line, were subjected to hypotonic shock to simulate needling stimulation. Extracellular ATP and adenosine levels were quantified using luciferase-luciferin assay and ELISA, respectively. Acupuncture-induced prompt analgesia was impaired by inhibiting CD39 activities to prevent the degradation of ATP to AMP but was mimicked by using CD39 agonists. Acupuncture-induced ATP accumulation exhibited synchronous changes. Similarly, acupuncture analgesia was hindered by suppressing CD73 to prevent the conversion of AMP to adenosine. Furthermore, the acupuncture effect was replicated by agonism at P2Y2Rs but inhibited by antagonism at them. Acupuncture upregulated CD73 and P2Y2Rs but not CD39. Immunofluorescent labeling demonstrated that keratinocytes were a primary site for these proteins. Shallow acupuncture also demonstrated antinociception. In vitro tests showed that hypotonic shock induced HaCaT cells to release ATP and adenosine, which was impaired by suppressing CD39 and CD73, respectively. Finally, agonism at P2Y2Rs promoted ATP release and [Ca2+]i rise. CD39 at the acupoints contributes to the analgesic mechanism of acupuncture. It may facilitate adenosine signaling in conjunction with CD73 or provide an appropriate ATP milieu for P2Y2Rs. Skin tissue may be one of the scenes for these signalings.

Extracellular ATP Release Triggered by 131I-Trastuzumab Mitigates Radiation-Induced Reduction in Cell Viability through the P2Y6 Receptor in SKOV3 Cells.

Intracellular ATP is released outside cells by various stimuli and is involved in cytoprotection by activating purinergic receptors. However, it remains unclear whether targeted radionuclide therapy induces extracellular ATP release. Here, we prepared 131I-labeled trastuzumab (131I-trastuzumab) and examined extracellular ATP release and its roles in 131I-trastuzumab's growth inhibitory effects. 131I-trastuzumab was prepared by labeling with the chloramine-T method. The binding of 131I-trastuzumab to cells was investigated using the human epidermal growth factor receptor 2 (HER2)-positive cells (SKOV3) and the HER2-negative cell (MCF7). Extracellular ATP was determined by measuring chemiluminescence using a luciferin-luciferase reagent. The growth inhibitory effects of 131I-trastuzumab were investigated by colony formation assay. 131I-trastuzumab bound exclusively to SKOV3 cells. Treatment with 131I-trastuzumab at 4 MBq/mL and higher concentrations significantly increased extracellular ATP levels, whereas non-radioactive trastuzumab didn't. This suggested that ATP release was specifically induced by radiation derived from 131I. The growth inhibitory effects of 131I-trastuzumab were significantly enhanced by pretreatment with apyrase (ecto-ATPase) or MRS2578 (a P2Y6-selective antagonist), whereas they were significantly reduced by treatment with a P2Y6-selective agonist. In conclusion, 131I-trastuzumab induced extracellular ATP release, and the released ATP was shown to be involved in mitigating radiation-induced reduction in cell viability through P2Y6 receptor.

Human Disabled-2 regulates thromboxane A2 signaling for efficient hemostasis in thrombocytopenia.

Understanding platelet protein functions facilitates better assessment of platelet disorders. Megakaryocyte lineage-restricted human Disabled-2 knock-in (hDAB2-KI) mice are generated to delineate the functions of hDab2, a regulator of platelet function, in the control of bleeding associated with thrombocytopenia. Here we show that hDab2-KI mice with thrombocytopenia display decreased bleeding time when compared to the control mice. hDab2 augments thromboxane A2 (TxA2) mimetic U46619- but not other agonists-stimulated granule secretion, integrin activation, and aggregation at a lower platelet concentration in vitro. Binding of hDab2 to phosphatidic acid (PA) facilitates formation of the PA-hDab2-AKT complex leading to an increase in U46619-stimulated AKT-Ser473 phosphorylation and the first wave of ADP/ATP release. Consistent with these findings, hDab2 expression in platelets from patients with immune thrombocytopenic purpura is positively correlated with U46619-stimulated ATP release, which in turn inversely correlated with their bleeding tendency. hDab2 appears crucial in regulating bleeding severity associated with thrombocytopenia by a functional interplay with ADP/ATP release underlying TxA2 signaling.

Complement Molecule C3a Exacerbates Early Brain Injury After Subarachnoid Hemorrhage by Inducing Neuroinflammation Through the C3aR-ERK-P2X7-NLRP3 Inflammasome Signaling Axis.

An important aspect of the pathophysiology of early brain damage (EBI) after subarachnoid hemorrhage (SAH) is inflammasome-mediated neuroinflammation. It has been demonstrated that C3aR activation exacerbates neuronal damage in a number of neurological disorders. This study aims to explore the role of C3a in activating the NLRP3 inflammasome and exacerbating neuroinflammation after SAH. Preprocessing of RNA-seq transcriptome datasets using bioinformatics analysis, and screening of differentially expressed genes between SAH patients and healthy individuals from the GEO database. Internal carotid artery puncture was performed to establish SAH models in rats and mice. SAH grading, neurological scoring, brain water content, behavioral analysis, and assessments using ELISA, Western blot, immunofluorescence, and immunohistochemistry were conducted. An in vitro model of SAH was induced in BV-2 cells treated with heme (200μM). The mechanism of C3a in post-SAH neuroinflammation was studied by interfering with and inhibiting C3aR. Results showed that the expression of C3aR was upregulated in the GEO dataset (serum of SAH patients) and identified as a key differential gene in SAH. Further, elevated levels of C3a were found in the cerebrospinal fluid of clinically collected SAH patients. In the cerebral cortex and/or serum of SAH rats, expression of C3a, IL-1β, IL-6, TNF-α, CD11b, and Ki67 were significantly increased, while IL-10 was significantly decreased. Correlation analysis revealed that C3a showed negative correlation with IL-10 and positive correlation with IL-1β, IL-6, TNF-α, CD11b, and Ki67. After stimulation with heme, protein levels of C3a increased in BV-2 cells. Interfering with C3aR significantly reduced LDH release, IL-1β secretion, Caspase1 activation, levels of NLRP3 expression and ASC oligomerization, and ATP release after heme stimulation in BV-2. Subsequently, the addition of inhibitors of ERK1/2 phosphorylation demonstrated that C3a promotes ATP efflux by activating ERK1/2 phosphorylation, thereby activating P2X7. Further addition of JNJ-55308942 (a P2X7R antagonist) revealed that C3a activated the NLRP3 inflammasome via P2X7. Finally, administering SB290157 (a C3aR inhibitor) in vivo effectively alleviated brain edema, reduced mortality, improved Garcia score, ameliorated motor dysfunction, and suppressed inflammation and NLRP3 inflammasome activation in mice after SAH. Overall, C3a exacerbates EBI-associated NLRP3 inflammasome and neuroinflammation via the C3aR-ERK-P2X7 pathway after SAH. Inhibiting C3aR may serve as a one possible treatment approach to alleviate SAH after EBI.

Pannexin-1 regulation of ATP release promotes the invasion of pituitary adenoma.

Pannexin-1 (PANX1) channel participates in the development and progression of many tumor types, however, its role of PANX1 in invasive pituitary adenoma (PA) remains unknown. The current study was designed to investigate the role of PANX1 in invasion of PA. We examined the expression of PANX1 in 116 surgical invasion and non-invasion PA samples (60 for bulk transcriptome and 56 for immunohistochemistry). The effects of PANX1 on PA growth were assessed in vitro and xenograft models. Meanwhile, the metabolism changes of PA cells are explored via transcriptomics and metabolomics using integration strategy. PANX1 is significantly upregulated in invasive PA compared with noninvasive PA and pituitary gland, and have a potential diagnostic signature for invasive PA. Accordingly, overexpression of PANX1 could promote the proliferation and invasion of GH3 and MMQ cell lines in vitro and in vivo. Further metabolomics results confirme that overexpression of PANX1 could trigger changes in several metabolic pathways of GH3 cells. Among the dysregulated cellular metabolites, decreased intracellular ATP suggeste that PANX1 may promote the invasion of PA through impacting extracellular ATP concentration. Mechanistically, extracellular ATP might promote Ca2+ influx and upregulated the expression of MMP2/9 by activating P2X7R. Additionally, PANX1-ATP-P2 X7R signaling pathway might enhance GH3 cell invasion by remodeling the actin cytoskeleton. Our findings point to a pivotal role of PANX1 in promoting PA invasion, which indicated a potential therapeutic target for invasive PA.

Restoring Colistin Sensitivity in Multidrug-Resistant Pathogenic E. coli Using Cinacalcet Hydrochloride.

Restoring colistin's efficacy is crucial in addressing the resistance crisis of colistin. This study utilized a high-throughput screening method to identify 43 compounds from 800 FDA-approved drugs that exhibited significant antibacterial effects when combined with colistin. Among these, cinacalcet hydrochloride (CH) was selected for its potential synergistic effect with colistin against multidrug-resistant (MDR) E. coli strains, including mcr-1-positive strains. A series of experiments revealed that the combination of CH and colistin showed strong synergy, especially in mcr-1-positive strains, restoring colistin sensitivity. The combination significantly inhibited bacterial growth and reduced CFU counts more effectively than either drug alone. Additionally, CH and colistin together significantly inhibited biofilm formation and eradicated existing biofilms, as visualized through confocal microscopy. Mechanistic studies showed that the combination increased bacterial membrane permeability and disrupted membrane integrity. The treatment also elevated extracellular ATP release and ROS production, indicating oxidative stress-induced bacterial death. Safety evaluations showed that the combination did not increase toxicity in host cells. Finally, animal models further validated the combination's efficacy. Overall, this study showed that the combination of colistin and CH significantly restored colistin sensitivity in mcr-1-positive E. coli, revealing their synergistic antibacterial mechanism involving membrane damage and oxidative stress, with promising clinical applications.

Astrocytic GLUT1 reduction paradoxically improves central and peripheral glucose homeostasis.

Astrocytes are considered an essential source of blood-borne glucose or its metabolites to neurons. Nonetheless, the necessity of the main astrocyte glucose transporter, i.e., GLUT1, for brain glucose metabolism has not been defined. Unexpectedly, we found that brain glucose metabolism was paradoxically augmented in mice with astrocytic GLUT1 reduction (GLUT1ΔGFAP mice). These mice also exhibited improved peripheral glucose metabolism especially in obesity, rendering them metabolically healthier. Mechanistically, we observed that GLUT1-deficient astrocytes exhibited increased insulin receptor-dependent ATP release, and that both astrocyte insulin signaling and brain purinergic signaling are essential for improved brain function and systemic glucose metabolism. Collectively, we demonstrate that astrocytic GLUT1 is central to the regulation of brain energetics, yet its depletion triggers a reprogramming of brain metabolism sufficient to sustain energy requirements, peripheral glucose homeostasis, and cognitive function.

8343 The Role Of Pancreatic Nerve Activity On The Development Of Beta Cell Dysfunction With The Macrophage-Beta Cell Interaction

Abstract Disclosure: J. Yu: None. Y. Wang: None. L. Sha: None. Islet inflammation is a vital factor to the beta cell dysfunction which is driven by inflammatory cytokines TNF-α and IL-1β released by resident macrophages. Pancreatic nerve innervates islet function and our previous study suggested that pancreatic nerve activity might involved in the development of pancreatic beta cell dysfunction. However, it is not known whether pancreatic nerve activity modulates macrophage activity and contributes to the macrophage - beta cell interaction. The aim of our study was to investigate the role of nerve activity on it and the possible mechanism. Methods: Sprague Dawley Rats and high fat diet-induced obese rates were used. An intrapancreatic nerve truck with its intact innervated pancreatic islets were used for the study. The nerve activity was evoked with electric nerve stimulation and insulin and ATP released by beta cells, TNF-α released by macrophages, and IL-1β released mainly by macrophages were measured with nerve activation. Results: Insulin secretion was induced significantly with the nerve activation (8 Hz). With nerve activation, ATP level was significantly increased by 25.5 ± 11.7%. The increased releases of insulin and ATP were abolished with cholinergic M receptor blocker atropine. With nerve activation, TNF-α and IL-1β levels were increased by 25.3±7.6% and 51.8±11.7%, respectively (p<0.05). Interestingly, the increases of TNF-α and IL-1β with nerve activation were also blocked by atropine. Since it is known that acetylcholine does not induce pro-inflammatory cytokine release in macrophages, we suspected that the nerve activity induced TNF-α and IL-1β releases were indirect. ATP is likely a candidate for the indirect effect as receptors. With applying Suramin, a ATP receptor blocker, nerve activation increased TNF-α release was inhibited significantly and IL-1β release was trended to inhibited. atropine, an M receptor blocker, compared with the Control group, decreased by 88.0±3.7% and 63.1±19.6%, respectively (p< 0.01). In obese rats, nerve activation increased TNF-α and IL-1β content by 68.1 ± 22.6% and 39.7 ± 7.4%, respectively, and suramin significantly inhibited the nerve activation induced increase of TNF-α release and trended to inhibit IL-1β release. Conclusion: Our results suggested that the pancreatic nerve activity contribute to the macrophage-beta cell interaction in the development of beta cells dysfunction by enhancing ATP release from islet beta cells. Presentation: 6/3/2024

Branched oncolytic peptides target HSPGs, inhibit metastasis, and trigger the release of molecular determinants of immunogenic cell death in pancreatic cancer.

Immunogenic cell death (ICD) can be exploited to treat non-immunoreactive tumors that do not respond to current standard and innovative therapies. Not all chemotherapeutics trigger ICD, among those that do exert this effect, there are anthracyclines, irinotecan, some platinum derivatives and oncolytic peptides. We studied two new branched oncolytic peptides, BOP7 and BOP9 that proved to elicit the release of damage-associated molecular patterns DAMPS, mediators of ICD, in pancreatic cancer cells. The two BOPs selectively bound and killed tumor cells, particularly PANC-1 and Mia PaCa-2, but not cells of non-tumor origin such as RAW 264.7, CHO-K1 and pgsA-745. The cancer selectivity of the two BOPs may be attributed to their repeated cationic sequences, which enable multivalent binding to heparan sulfate glycosaminoglycans (HSPGs), bearing multiple anionic sulfation patterns on cancer cells. This interaction of BOPs with HSPGs not only fosters an anti-metastatic effect in vitro, as demonstrated by reduced adhesion and migration of PANC-1 cancer cells, but also shows promising tumor-specific cytotoxicity and low hemolytic activity. Remarkably, the cytotoxicity induced by BOPs triggers the release of DAMPs, particularly HMGB1, IFN-β and ATP, by dying cells, persisting longer than the cytotoxicity of conventional chemotherapeutic agents such as irinotecan and daunorubicin. An in vivo assay in nude mice showed an encouraging 20% inhibition of tumor grafting and growth in a pancreatic cancer model by BOP9.

Control of nerve-mediated and urothelial ATP release by a protein kinase G-dependent pathway in the mouse bladder

Aim:ATP signalling is involved in urinary bladder motor and sensory pathways, including stimulation-mediated release from parasympathetic varicosities to detrusor muscle and from urothelial cells when mechanically stressed. Both modalities are present in humans and other mammals but are especially prominent in overactive bladder syndromes. There is therefore an unmet need to understand how to regulate such release. This study tested the hypothesis that the nitric oxide (NO•)/ soluble guanylate cyclase (sGC)/ cyclic GMP/ protein kinase-G (PKG) pathway has a central role. Methods:In vitro nerve-mediated contractions and ATP/acetylcholine (ACh) release were measured from bladder wall strips, as was ATP release from urothelial cell suspensions subject to mechanical stresses. Enhanced spontaneous contractile activity was also measured in bladder wall preparations of spinal cord-injured mice. Interventions were designed to increase cellular cGMP levels (a cell-permeable cGMP analogue, a NO•donor, a phosphodiesterase inhibitor (PDEI), a sGC activator), or agents to reduce activity of pathway enzymes (sCG or PKG). Results:ATP-dependent contractions were reduced by the above interventions, as was ATP release; but ACh-dependent contractions and ACh release were unaffected. Spontaneous contractile activity was also reduced by the cGMP analogue and by a PDEI. ATP release from urothelial cell suspensions was also reduced by similar interventions. Conclusions:ATP release from efferent nerves and from urothelial cells were selectively reduced by upregulating the NO•/sGC/cGMP/PKG pathway. Translational aspects are discussed with respect to purinergic pathways and overactive bladder pathologies.

Combination of Losartan and Platinum Nanoparticles with Photothermal Therapy Induces Immunogenic Cell Death Effective Against Neuroblastoma.

Photothermal therapy (PTT) is a promising therapeutic procedure with minimal side effects, which can not only kill tumor directly but also cause immunogenic cell death (ICD). However, most solid tumors, including neuroblastoma, are abundant in fibroblasts, which limit the penetration and delivery of nanoparticles. Losartan is an antihypertensive drug approved by the FDA, and it has been proved to have the effect of breaking down excessive ECM network. In this study, we investigated the application and potential mechanism of the combination of mesoporous platinum nanoparticles (MPNs) and losartan in the PTT of neuroblastoma by establishing neuroblastoma models in vitro and in vivo. Compared to the MPNs group without 808 nm laser irradiation, Neuro-2a cells pretreated with PTT and losartan showed lower survival rates, increased surface calreticulin, and higher release of HMGB1 and ATP. The group also exhibited the highest anti-tumor efficacy in vivo, with a tumor suppression ratio of approximately 80%. Meanwhile, we found that CD3+ T cells, CD4+ T cells and CD8+ T cells from the peripheral blood of experimental group mice were significantly higher than control groups, and CD8+PD-1+ cells were significantly lower than those in MPNs + Los group and Los + laser group. And the expression of PD-1 and α-SMA in Neuro-2a tumors tissue was reduced. Furthermore, losartan could reduce damage of liver function caused by MPNs and laser treatment. This study demonstrated that losartan-induced fibroblasts ablation increased the penetration of MPNs into tumors. Enhanced penetration allowed PTT to kill more tumor cells and synergistically activate immune cells, leading to ICD, indicating the great promise of the strategy for treating neuroblastoma in vivo.

119 - Modulating cyclic nucleotides reduces stress-induced ATP release from isolated urothelial cells of the mouse bladder

119 - Modulating cyclic nucleotides reduces stress-induced ATP release from isolated urothelial cells of the mouse bladder

Neuroinflammatory responses and blood–brain barrier injury in chronic alcohol exposure: role of purinergic P2 × 7 Receptor signaling

Alcohol consumption leads to neuroinflammation and blood‒brain barrier (BBB) damage, resulting in neurological impairment. We previously demonstrated that ethanol-induced disruption of barrier function in human brain endothelial cells was associated with mitochondrial injury, increased ATP and extracellular vesicle (EV) release, and purinergic receptor P2 × 7R activation. Therefore, we aimed to evaluate the effect of P2 × 7R blockade on peripheral and neuro-inflammation in ethanol-exposed mice. In a chronic intermittent ethanol (CIE)-exposed mouse model, P2 × 7R was inhibited by two different methods: Brilliant Blue G (BBG) or gene knockout. We assessed blood ethanol concentration (BEC), brain microvessel gene expression by using RT2 PCR array, plasma P2 × 7R and P-gp, serum ATP, EV-ATP, number of EVs, and EV mtDNA copy numbers. An RT2 PCR array of brain microvessels revealed significant upregulation of proinflammatory genes involved in apoptosis, vasodilation, and platelet activation in CIE-exposed wild-type animals, which were decreased 15–50-fold in BBG-treated–CIE-exposed animals. Plasma P-gp levels and serum P2 × 7R shedding were significantly increased in CIE-exposed animals. Pharmacological or genetic suppression of P2 × 7R decreased receptor shedding to levels equivalent to those in control group. The increase in EV number and EV-ATP content in the CIE-exposed mice was significantly reduced by P2 × 7R inhibition. CIE mice showed augmented EV-mtDNA copy numbers which were reduced in EVs after P2 × 7R inhibition or receptor knockout. These observations suggested that P2 × 7R signaling plays a critical role in ethanol-induced brain injury. Increased extracellular ATP, EV-ATP, EV numbers, and EV-mtDNA copy numbers highlight a new mechanism of brain injury during alcohol exposure via P2 × 7R and biomarkers of such damage. In this study, for the first time, we report the in vivo involvement of P2 × 7R signaling in CIE-induced brain injury.

The epsilon toxin from Clostridium perfringens stimulates calcium-activated chloride channels, generating extracellular vesicles in Xenopus oocytes.

The epsilon toxin (Etx) from Clostridium perfringens has been identified as a potential trigger of multiple sclerosis, functioning as a pore-forming toxin that selectively targets cells expressing the plasma membrane (PM) myelin and lymphocyte protein (MAL). Previously, we observed that Etx induces the release of intracellular ATP in sensitive cell lines. Here, we aimed to re-examine the mechanism of action of the toxin and investigate the connection between pore formation and ATP release. We examined the impact of Etx on Xenopus laevis oocytes expressing human MAL. Extracellular ATP was assessed using the luciferin-luciferase reaction. Activation of calcium-activated chloride channels (CaCCs) and a decrease in the PM surface were recorded using the two-electrode voltage-clamp technique. To evaluate intracellular Ca2+ levels and scramblase activity, fluorescent dyes were employed. Extracellular vesicles were imaged using light and electron microscopy, while toxin oligomers were identified through western blots. Etx triggered intracellular Ca2+ mobilization in the Xenopus oocytes expressing hMAL, leading to the activation of CaCCs, ATP release, and a reduction in PM capacitance. The toxin induced the activation of scramblase and, thus, translocated phospholipids from the inner to the outer leaflet of the PM, exposing phosphatidylserine outside in Xenopus oocytes and in an Etx-sensitive cell line. Moreover, Etx caused the formation of extracellular vesicles, not derived from apoptotic bodies, through PM fission. These vesicles carried toxin heptamers and doughnut-like structures in the nanometer size range. In conclusion, ATP release was not directly attributed to the formation of pores in the PM, but to scramblase activity and the formation of extracellular vesicles.

Activation of osmo-sensitive LRRC8 anion channels in macrophages is important for micro-crystallin joint inflammation

Deposition of monosodium urate and calcium pyrophosphate (MSU and CPP) micro-crystals is responsible for painful and recurrent inflammation flares in gout and chondrocalcinosis. In these pathologies, the inflammatory reactions are due to the activation of macrophages responsible for releasing various cytokines including IL-1β. The maturation of IL-1β is mediated by the multiprotein NLRP3 inflammasome. Here, we find that activation of the NLRP3 inflammasome by crystals and concomitant production of IL-1β depend on cell volume regulation via activation of the osmo-sensitive LRRC8 anion channels. Both pharmacological inhibition and genetic silencing of LRRC8 abolish NLRP3 inflammasome activation by crystals in vitro and in mouse models of crystal-induced inflammation. Activation of LRRC8 upon MSU/CPP crystal exposure induces ATP release, P2Y receptor activation and intracellular calcium increase necessary for NLRP3 inflammasome activation and IL-1β maturation. We identify a function of the LRRC8 osmo-sensitive anion channels with pathophysiological relevance in the context of joint crystal-induced inflammation.

NADPH oxidase 1/4 dual inhibitor setanaxib suppresses platelet activation and thrombus formation

AimsThe production of reactive oxygen species (ROS) by NADPH oxidase (NOX) is able to induce platelet activation, making NOX a promising target for antiplatelet therapy. In this study, we examined the effects of setanaxib, a dual NOX1/4 inhibitor, on human platelet function and ROS-related signaling pathways. Materials and methodsIn collagen-stimulated human platelets, aggregometry, assessment of ROS and Ca2+, immunoblotting, ELISA, flow cytometry, platelet adhesion assay, and assessment of mouse arterial thrombosis were performed in this study. Key findingsSetanaxib inhibited both intracellular and extracellular ROS production in collagen-activated platelets. Additionally, setanaxib significantly inhibited collagen-induced platelet aggregation, P-selectin exposure from α-granule release, and ATP release from dense granules. Setanaxib blocked the specific tyrosine phosphorylation-mediated activation of Syk, LAT, Vav1, and Btk within collagen receptor signaling pathways, leading to reduced activation of PLCγ2, PKC, and Ca2+ mobilization. Setanaxib also inhibited collagen-induced activation of integrin αIIbβ3, which is linked to increased cGMP levels and VASP phosphorylation. Furthermore, setanaxib suppressed collagen-induced p38 MAPK activation, resulting in decreased phosphorylation of cytosolic PLA2 and reduced TXA2 generation. Setanaxib also inhibited ERK5 activation, affecting the exposure of procoagulant phosphatidylserine. Setanaxib reduced thrombus formation under shear conditions by preventing platelet adhesion to collagen. Finally, in vivo administration of setanaxib in animal models led to the inhibition of arterial thrombosis. SignificanceThis study is the first to show that setanaxib suppresses ROS generation, platelet activation, and collagen-induced thrombus formation, suggesting its potential use in treating thrombotic or cardiovascular diseases.

A novel heterozygous missense variant of PANX1 causes human oocyte death and female infertility

Pannexin1 (PANX1) is a highly glycosylated membrane channel-forming protein, which has been found to implicate in multiple physiological and pathophysiological functions. Variants in the PANX1 gene have been reported to be associated with oocyte death and recurrent in vitro fertilization failure. In this study, we identified a novel heterozygous PANX1 variant (NM_015368.4 c.410 C > T (p.Ser137Leu)) associated with the phenotype of oocyte death in a non-consanguineous family, followed by an autosomal dominant (AD) mode. We explored the molecular mechanism of the novel variant and the variant c.976_978del (p.Asn326del) that we reported previously. Both of the variants altered the PANX1 glycosylation pattern in cultured cells, led to aberrant PANX1 channel activation, affected ATP release and membrane electrophysiological properties, which resulted in mouse and human oocyte death in vitro. For the first time, we presented the direct evidence of the effect of the PANX1 variants on human oocyte development. Our findings expand the variant spectrum of PANX1 genes associated with oocyte death and provide new support for the genetic diagnosis of female infertility.

Activation of Piezo1 channels enhances spontaneous contractions of isolated human bladder strips via acetylcholine release from the mucosa

Enhanced spontaneous bladder contractions (SBCs) have been thought one of the important underlying mechanisms for detrusor overactivity (DO). Piezo1 channel has been demonstrated involved in bladder function and dysfunction in rodents. We aimed to investigate the modulating role of Piezo1 in SBCs activity of human bladder. Human bladder tissues were obtained from 24 organ donors. SBCs of isolated bladder strips were recorded in organ bath. Piezo1 expression was examined with reverse transcription-quantitative polymerase chain reaction and immunofluorescence staining. ATP and acetylcholine release in cultured human urothelial cells was measured. Piezo1 is abundantly expressed in the bladder mucosa. Activation of Piezo1 with its specific agonist Yoda1 (100 nM–100 μM) enhanced the SBCs activity in isolated human bladder strips in a concentration-dependent manner. The effect of Yoda1 mimicked the effect of a low concentration (30 nM) of carbachol, which can be attenuated by removing the mucosa, blocking muscarinic receptors with atropine (1 μM), and blocking purinergic receptors with pyridoxal-phosphate-6-azophenyl-2′,4′-disulfonate (PPADS, 30 μM), but not by tetrodotoxin (1 μM). Activation of urothelial Piezo1 with Yoda1 (30 μM) or hypotonic solution induced the release of ATP and acetylcholine in cultured human urothelial cells. In patients with benign prostatic hyperplasia, greater Piezo1 expression was observed in bladder mucosa from patients with DO than patients without DO. We conclude that upregulation and activation of Piezo1 may contribute to DO generation in patients with bladder outlet obstruction by promoting the urothelial release of ATP and acetylcholine. Inhibition of Piezo1 may be a novel therapeutic approach in the treatment of overactive bladder.

Activation of P2X7R Inhibits Proliferation and Promotes the Migration and Differentiation of Schwann Cells.

In the vertebrate nervous system, myelination of nerve fibers is crucial for the rapid propagation of action potentials through saltatory conduction. Schwann cells-the main glial cells and myelinating cells of the peripheral nervous system-play a crucial role in myelination. Following injury during the repair of peripheral nerve injuries, a significant amount of ATP is secreted. This ATP release acts to trigger the dedifferentiation of myelinating Schwann cells into repair cells, an essential step for axon regeneration. Subsequently, to restore nerve function, these repair cells undergo redifferentiate into myelinating Schwann cells. Except for P2X4R, purine receptors such as P2X7R also play a significant role in this process. In the current study, decreased expression of P2X7R was observed after sciatic nerve injury, followed by a gradual increase to the normal level of P2X7R expression. In vivo experiments showed that the activation of P2X7R using an agonist injection promoted remyelination, while the antagonists hindered remyelination. Further, in vitro experiments supported these findings and demonstrated that P2X7R activation inhibited the proliferation of Schwann cells, but it promoted the migration and differentiation of the Schwann cells. Remyelination is a prominent feature of the nerve regeneration. In the current study, it was proposed that the manipulation of P2X7R expression in Schwann cells after nerve injury could be effective in facilitating nerve remyelination.

Keratinocyte Piezo1 and CD39 initiated the acupuncture analgesic signals via Co-regulating extracellular ATP mobilization at acupoints

Acupoints are the initiation sites for acupuncture analgesic signals, where adenosine signaling plays a crucial role. A comprehensive understanding of this matter will guide clinicians to optimize acupuncture manipulations to improve acupuncture effectiveness. Recently, keratinocyte Piezo1 channels and cascade ATP release are independently unveiled to be essential for the skin tactile sensation. Thus, we aimed to investigate whether keratinocyte Piezo1-mediated ATP release, in orchestration with CD39, contributed to this initiation mechanism via producing adenosine. 20-min needling was administered at the unilateral ST36 acupoint on the acute ankle arthritis rats. The pain thresholds in the affected hindpaws were determined. Interstitial ATP and adenosine were extracted with microdialysis and assessed by luciferase-luciferin and HPLC, respectively. To simulate needling stimulation, keratinocyte HaCaT cells were subjected to hypotonic shock. ATP release and live calcium imaging were conducted. Immunofluorescence labeling showed the presence of Piezo1 and CD39 on keratinocytes. Acupuncture led to a prompt analgesic effect, as well as a temporary accumulation of ATP and adenosine. Activating adenosine A1 receptors, promoting ATP release by activating Piezo1, or facilitating ATP hydrolysis by potentiating CD39 achieved anti-nociceptive effects. Conversely, altering these modulations in the opposite direction reversed the subsequent effects of acupuncture. Needling-induced accumulation of interstitial ATP parallelly changed with these modulations. Hypotonic shock led to ATP release and [Ca2+]i rise in HaCaT, which were impeded by introducing siRNA-Piezo1, or replicated by agonism at Piezo1. These findings suggest that keratinocyte Piezo1 and CD39 co-mediated ATP mobilization at acupoints contributes to the initiation signals of acupuncture analgesia via triggering adenosine signaling. SectionPhysical/Mental practices (acupuncture) Taxonomy (classification by evise)pain and analgesia.