P2Y Receptors Research Articles

Trimethylamine-N-oxide aggravated sympathetic activation in D-galactose induced aging rats by down-regulating P2Y12 receptor in microglia

This study aimed to determine whether trimethylamine N-oxide (TMAO) was involved in sympathetic activation in aging and the underline mechanisms. Our hypothesis is that TMAO reduces P2Y12 receptor and induces microglia-mediated inflammation in the paraventricular nucleus, then leading to sympathetic activation in aging. Eighteen young adults (20-40 years old) and sixteen old adults (65-90 years old) were involved in the study. Aging rats were established by injecting D-galactose (200 mg/kg/d) subcutaneously for 12 weeks. TMAO (120 mg/kg/d) or 1% 3, 3-dimethyl-l-butanol (DMB, a structural analog of choline, inhibiting TMA formation) was administrated in drinking water for 12 weeks to investigate their effects on neuroinflammation and sympathetic activation in aging rats. Heart rate variability was analyzed by 24 h ambulatory ECG multichannel recording system (CT-083S Holter ECG recorder, BENEWARE, Hangzhou) in young and old adults. The PowerLab 15T data acquisition system (AD Instruments, Australia) was used to record blood pressure and renal sympathetic nerve activity in the rats. Plasma levels of TMAO, noradrenaline, and IL-1β in old adults were higher than those in young group. In addition, standard deviation of all normal to normal intervals and standard deviation of the average of normal to normal intervals were lower in old adults and negative correlated with TMAO, which indicating sympathetic activation in old adults and related to the increased TMAO. Rats treatment with D-gal showed increased senescence-associated protein, microglia-mediated inflammation levels and decreased P2Y12 receptor in the paraventricular nucleus. Plasma levels of TMAO, noradrenaline, and IL-1β were increased, accompanied by enhanced renal sympathetic nerve activity. While TMAO supplementation aggravated the above phenomenons, and DMB abated them. These findings suggested that TMAO might contribute to the sympathetic hyperactivity of aging via downregulating P2Y12 receptor in microglia and increasing inflammation in the paraventricular nucleus. These results may provide a new target for the prevention and treatment of aging and aging-related diseases. This work was supported by the Program for the National Natural Science Foundationof China (32271155 and 31671185), the Science and Technology Project of the Hebei Education Department (ZD2021076), the Youth Top Talent Foundation of Hebei Province of China and the Program of Clinical Medicine Innovation Research Team of Hebei Medical University (2022LCTD-A1). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

GPER1 Activation Upregulates Renal Purinergic P2Y2 Receptor Expression and Lowers Blood Pressure in Ovariectomized Rats Fed High Salt Diet

Renal purinergic P2Y2 receptor promotes urinary Na+ excretion via inhibiting epithelial Na+ channel (ENaC) activity. Recent evidence implicates that ovarian hormones regulate P2Y2/ENaC natriuretic pathway, however the underlying mechanism remains unclear. Estradiol activates the G protein-coupled estrogen receptor 1 (GPER1), which promotes natriuresis in females. Taken together, we hypothesized that GPER1 activation regulates renal P2Y2 receptor expression and maintains blood pressure in ovariectomized (OVX) rats. To test our hypothesis, we determined the effect of pharmacologic activation GPER1 on (i) blood pressure and (ii) mRNA expression of renal P2Y2 receptor. In particular, female (16–20 weeks of age) Sprague Dawley rats were implanted with telemeters. After recording baseline blood pressure, rats were ovariectomized and simultaneously implanted with an osmotic minipump to deliver either G1, selective GPER1 agonist (OVX+G1), or Vehicle (OVX+Veh) for 3 weeks. Rats were fed a normal salt (NS, 0.49% NaCl) throughout the study and challenged with a high salt (HS, 4% NaCl) during the last week. Finally, animals were euthanized, renal cortex and medulla were assessed for P2Y2 and αENaC mRNA expression. We found that OVX+Veh rats fed a HS diet had greater mean arterial pressure (MAP) when compared to their baseline values prior to ovariectomy (113 ± 1 vs. 105 ± 1 mmHg; p < 0.01; n = 6). Interestingly, OVX+G1 rats fed a HS diet did not elicit significant changes in MAP when compared to their baseline values (106 ± 3 vs. 104 ± 2 mmHg; p = 0.25; n = 6). Moreover, renal cortical P2Y2 mRNA expression in OVX+G1 rats was higher compared to corresponding vehicle-treated rats (1.95 ± 0.21 vs. 1.00 ± 0.17 fold change from OVX+Veh; p < 0.01; n = 6-7/group). Renal outer and inner medullary P2Y2 mRNA expression elicited similar trends; however, it did not reach statistical significance. No differences were evident in the renal αENaC mRNA expression in response to G1 treatment. We also extended the study in female mice to determine the effect of genetic deletion of GPER1 on renal P2Y2 receptor mRNA expression. We found that P2Y2 mRNA expression in kidneys obtained from GPER1 KO mice was markedly lower when compared to wildtype litter mates. However, no differences were detected in the mRNA expression of αENaC in response to GPER1 deletion. The current results indicate that GPER1 activity upregulates the renal P2Y2 expression which may contribute to preventing the increase in blood pressure in HS-fed OVX animals, possibly by promoting natriuresis. Additional studies are required to improve our understanding for GPER1/P2Y2/ENaC signaling pathway in the postmenopausal female population. NIH/NIDDK R00DK119413 to EYG. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Purinergic Signaling Drives Multiple Aspects of Rotavirus Pathophysiology

Background: Rotavirus causes life-threatening diarrhea in children, resulting in ~200,000 deaths each year. Rotavirus infects a limited number of cells at the tips of the villi in the small intestine; however, rotavirus is known to dysregulate cells distant from the site of infection through paracrine signaling. We recently identified that rotavirus infected cells release the purinergic signaling molecule ADP, which binds to the P2Y1 receptor on nearby uninfected cells; causing a signaling cascade that affects distant uninfected cells. In vitro P2Y1 was found to contribute to chloride and serotonin secretion; suggesting P2Y1 may activate pathways responsible for diarrhea. Hypothesis: We hypothesize that P2Y1 orchestrates cell-cell communication involved in diarrhea and infection severity. Methods: To elucidate the role of purinergic signaling via P2Y1 receptors during rotavirus infection, we used the mouse-like rotavirus (rD6/2) to investigate the effects of purinergic signaling in the context of homologous murine rotavirus infection in vivo. C57Black6 mouse pups were orally gavaged rD6/2 rotavirus at day 4-6 of age and assessed over the course of 5 days. Beginning at day 1 post infection, infected pups were treated daily by oral gavage with saline or 4mg/kg MRS2500, a P2Y1-selective, competitive antagonist. Stool was collected and scored for diarrhea daily prior to each treatment. Pups were euthanized and small intestine tissue was collected at 3- and 5-days post infection for immunostaining, qRT-PCR and luminal contents. Intestinal organoids derived from Balb/C pup jejunum were inoculated with rD6/2 rotavirus, followed by supplementation with vehicle or MRS2500 to assess fluid secretion by organoid swelling over time. Results: Rotavirus-infected pups exhibited significant diarrhea incidence and high diarrhea scores on days 2, 3, and 4 post infection. Treatment of rotavirus-infected mouse pups with MRS2500 resulted in decreased severity and incidence of diarrhea compared to vehicle treated controls. This was consistent with in vitro, rD6/2-infected organoids exhibiting a significant increase in organoid swelling compared to uninfected organoids, which was significantly prevented by inhibition of P2Y1 signaling. Viral stool shedding from MRS2500 treated pups was significantly lower than saline-treated pups starting at day 4 post infection, which suggests P2Y1 signaling may amplify rotavirus replication in vivo. Finally, transmission experiments in litters with infected (but not treated) and pretreated MRS2500 uninfected pups show a decreased incidence in diarrhea suggesting that P2Y1 inhibition has a potential protective role in reducing the effects of transmission. Conclusion: Collectively these findings establish a conserved role of purinergic signaling in the pathophysiology of rotavirus infection. Additionally, our data indicates P2Y1 as a new candidate for host-targeted therapeutics that could have both antiviral and antidiarrheal effects against rotavirus pathophysiology. R01 DK115507 (Hyser) R01 AI158683 (Hyser)APS Postdoctoral Fellowship (Engevik) F32 DK130288 (Engevik). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Purinergic Signaling and its Role in the Stem Cell Differentiation.

Purinergic signaling is a mechanism in which extracellular purines and pyrimidines interact with specialized cell surface receptors known as purinergic receptors. These receptors are divided into two families of P1 and P2 receptors, each responding to different nucleosides and nucleotides. P1 receptors are activated by adenosine, while P2 receptors are activated by pyrimidine and purines. P2X receptors are ligand-gated ion channels, including seven subunits (P2X1-7). However, P2Y receptors are the G-protein coupled receptors comprising eight subtypes (P2Y1/2/4/6/11/12/13/14). The disorder in purinergic signaling leads to various health-related issues and diseases. In various aspects, it influences the activity of non-neuronal cells and neurons. The molecular mechanism of purinergic signaling provides insight into treating various human diseases. On the contrary, stem cells have been investigated for therapeutic applications. Purinergic signaling has shown promising effect in stem cell engraftment. The immune system promotes the autocrine and paracrine mechanisms and releases the significant factors essential for successful stem cell therapy. Each subtype of purinergic receptor exerts a beneficial effect on the damaged tissue. The most common effect caused by purinergic signaling is the proliferation and differentiation that treat different health-related conditions.

Targeting purinergic signaling in platelets ameliorates the bacterial burden and reduces the cytokine storm in the peritoneal cavity during intra-abdominal sepsis

Sepsis is a complex clinical syndrome of the host response to an infection, involving a pathogenic cytokine storm that drives inflammatory injury in multiple organ systems. The abdomen is a major site of sepsis, contributing to high mortality. Platelets express the purinergic receptors P2Y1 and P2Y12; once activated, these receptors mediate the secretion of pro-inflammatory mediators that contribute to organ damage in sepsis. Systemic blockade of P2Y1 or P2Y12 decreased organ damage and inflammatory cytokine levels in a sex-related manner during sepsis. Here, we hypothesize that blocking P2Y1 or P2Y12 activity enhances pathogen clearance in the peritoneal cavity during intra-abdominal sepsis in a sex-specific manner. Male and female C57BL6/6J mice underwent sham surgery or cecal ligation and puncture (CLP) to induce sepsis. P2Y1 or P2Y12 antagonists, MRS2279 (10 mg/kg) and Ticagrelor (30 mg/kg) respectively, were administered intraperitoneally after surgery. The peritoneal cavity fluid (PCF) was collected 24 hours post-surgery by peritoneal lavage. To assess cell recruitment in the cavity, we measured leukocyte and platelet counts using Hemavet® Multispecies Hematology System. To assess inflammation, we measured PCF levels of the cytokines MIP-1α and Rantes as well as bacterial clearance. The ileum of the small intestinal tissue samples were collected 24 hours post-surgery and platelet infiltration was measured by platelet factor 4 (PF4) content in the tissue using an ELISA kit. In response to the P2Y1 or P2Y12 blocker, we noted a significant reduction in the bacteria content in the PCF of CLP mice. Blocking P2Y12 but not P2Y1 reduced leukocyte recruitment, while platelet counts were reduced only with P2Y1 blockade in septic males. The sepsis-induced increase in MIP-1α levels was not noted upon P2Y1 but not P2Y12 blockage in the PCF of septic males. However, Rantes levels in the PCF were reduced for either treatment in males compared to the untreated CLP. The platelet marker PF4 in the ileum was increased during sepsis but reduced after either treatment in sepsis males as compared to the untreated CLP. In female CLP mice, a significant reduction in bacterial burden in the PCF in response to the P2Y1 but not the P2Y12 blocker was shown. Blocking P2Y1 or P2Y12 reduced leukocyte recruitment and platelet counts in female CLP mice. As observed in males, PF4 was increased in the ileum during sepsis but reduced following exposure to either treatment in females. No change was noted for MIP-1α or Rantes levels in the females among all the septic groups. Our data indicate that blocking purinergic signaling and in particular P2Y12 in the peritoneal cavity in males prevents bacterial spreading and diminishes cytokine levels, indicating that it could be an effective treatment for intra-abdominal sepsis. However, in female mice blocking the receptor P2Y1, but not P2Y12 has shown to be optimal. Targeting purinergic signaling is a promising sex-specific therapeutic strategy for sepsis. This work was supported by the Research grant AI156627-01 (EL) from the National Institute of Health. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Assessing the Impact of Morphine on Adverse Outcomes in ACS Patients Treated with P2Y12 Inhibitors: Insights from Multiple Real-World Evidence.

Mechanistic studies showed that morphine may impair the antiplatelet effect of P2Y12 inhibitors. However, Several clinical studies with cardiovascular events as an outcome are contradictory, and the broader impact of this drug interaction on additional organ systems remains uncertain. With multisource data, this study sought to determine the effects of morphine interaction with P2Y12 inhibitors on major adverse outcomes comprehensively, and identify the warning indicators. Interaction signals were sought in 187,919 safety reports from the FDA Adverse Event Reporting System (FAERS) database, utilizing reporting odds ratios (repOR). In a cohort of 5240 acute coronary syndrome patients, the analyses were validated, and the biological effects of warning indicators were further studied with Mendelian randomization and mediation analysis. Potential risk of renal system adverse events in patients cotreated with morphine is significantly higher in FAERS (repOR 4.83, 95% CI 4.42-5.28, false discovery rate adjusted-P =3.55*10-209). The analysis of in-house patient cohorts validated these results with an increased risk of acute kidney injury (adjusted OR: 1.65; 95% CI: 1.20 to 2.26), and we also found a risk of myocardial infarction in patients treated with morphine (adjusted OR: 1.55; 95% CI: 1.14 to 2.11). The Morphine group exhibited diminished Plateletcrit (PCT) levels post-surgery and lower PCT levels were associated with an increased risk of AKI. The administration of morphine in patients treated with P2Y12 receptor inhibitors should be carefully evaluated. PCT may serve as a potential warning indicator for morphine-related renal injury.

PVN predisposes microglia to be susceptible to hemodynamic signals and promote sympathetic excitation in hypertension

Hypertension is usually accompanied with an elevated sympathetic tonicity, but how sympathetic hyperactivity is triggered is not fully understood. Recent advances reveal that microglia-centered neuroinflammation contributes to sympathetic excitation in hypertension. In this study, we performed a temporospatial analysis of microglia at both morphological and transcriptomic levels, and found that microglia in the hypothalamic paraventricular nucleus (PVN) were early responders to hypertensive challenges. PVN is the central hub for maintaining cardiovascular function via regulation of fluid balance and sympathetic outflow. Comprehensive vasculature analyses unveiled that PVN was characterized by high capillary density, thin vessel diameter, and complex vascular topology among brain regions. As such, PVN is susceptible to the penetration of ATP released from the vasculature in response to hemodynamic disturbance after blood pressure increase. ATP ligation to microglial P2Y12 receptor is responsible for the microglial accumulation and activation in the PVN. Both pharmacological blockade and genetic ablation of microglial P2Y12 could substantially restrain blood pressure increase under hypertensive challenge. Together, these findings disclose that a unique vasculature pattern results in the vulnerability of PVN pre-sympathetic neurons to hypertension-associated inflammatory insults, which is mediated by microglia. NSFC82170441. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Sex-Dependent Regulation of Mucin Gene Transcription and Goblet Cell Secretion Machinery Following Intra-Airway IL-13 in Mice with Conditional Loss of Club Cell Creb1

IL-13 is an important effector molecule in allergic asthma, converting secretoglobin-positive club cells into mucin-secreting goblet cells and promoting mucin hypersecretion. IL-13-mediated conversion of club cells to goblet cells requires decreased gene expression of forkhead box A2 ( FOXA2) and increased gene expression of SAM pointed domain containing ETS transcription factor ( SPDEF). In addition, IL-13-mediated mucin hypersecretion may include modulation of purinergic and muscarinic receptors that control basal and stimulated mucus secretion, respectively. We recently found that the cAMP response element-binding protein (CREB), a ubiquitous transcription factor, directly binds to FOXA2 and modulates mucus secretion mechanisms in mice. Here we tested the hypothesis that conditional loss of club cell Creb1 in murine airways modulates the pro-mucin effects of IL-13. Loss of club cell Creb1 augmented IL-13-mediated increases in gene expression of the major gel-forming secreted mucins Muc5ac and Muc5b in male murine airways, with no effect on IL-13-mediated increases in Muc5ac and Muc5b in female murine airways. Examination of mucin secretion mechanisms revealed that IL-13 decreased muscarinic 3 receptor ( M3R) mRNA expression in male murine airways, whereas loss of club cell Creb1 prevented this, resulting in a significant treatment by genotype interaction. Interestingly, in female airways, a main effect of genotype was observed, with loss of club cell Creb1 reducing M3R mRNA expression in the airway. Examination of the purinergic receptor P2Y ( P2ry2) mRNA revealed a main treatment effect for IL-13 to increase P2ry2 expression in male murine airways with no impact of loss of club cell Creb1. In the females, IL-13 increased P2ry2 mRNA in both genotypes, with loss of club cell Creb1 significantly blunting the effect of IL-13 on P2ry2 mRNA. Lastly, we examined goblet cell density and mucin secretion mechanisms using Alcian Blue-PAS staining post in vivo stimulation with a muscarinic agent. We found no major effect of treatment or genotype in the density of goblet cells containing acidic mucins in either male or female airways. In contrast, both males and females showed IL-13-mediated increases in the density of goblet cells containing neutral mucins that was not impacted by genotype. Our preliminary findings suggest that loss of club cell Creb1 decreases molecular mucin secretion mechanisms in male and female airways, and increases Muc5ac and Muc5b mRNA in male airways, though a corresponding genotype-dependent increase in goblet cell density post cholinergic stimulation was not observed. Thus, we conclude that loss of club cell Creb1 causes changes to molecules important for IL-13-mediated mucin hypersecretion, without apparent functional benefit or detriment to the murine airway. This work was supported by the National Institutes of Health (OD026582, HL152101), the Cystic Fibrosis Foundation (REZNIKO20I0, REZNIKO19I0), the Katie Rose Foundation (AWD08203), and the University of Florida McKnight Career Accelerator Award. Angelina Bonilla was funded by the National institutes of Health (R25GM115298). Pedro Trevizan Bau receives the University of Florida McKnight Brain Institute Gator NeuroScholar Fellowship. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Testosterone Enhances KV Currents and Airway Smooth Muscle Relaxation Induced by ATP and UTP through P2Y4 Receptors and Adenylyl Cyclase Pathway.

Numerous studies suggest the involvement of adenosine-5'-triphosphate (ATP) and similar nucleotides in the pathophysiology of asthma. Androgens, such as testosterone (TES), are proposed to alleviate asthma symptoms in young men. ATP and uridine-5'-triphosphate (UTP) relax the airway smooth muscle (ASM) via purinergic P2Y2 and P2Y4 receptors and K+ channel opening. We previously demonstrated that TES increased the expression of voltage-dependent K+ (KV) channels in ASM. This study investigates how TES may potentiate ASM relaxation induced by ATP and UTP. Tracheal tissues treated with or without TES (control group) from young male guinea pigs were used. In organ baths, tracheas exposed to TES (40 nM for 48 h) showed enhanced ATP- and UTP-evoked relaxation. Tetraethylammonium, a K+ channel blocker, annulled this effect. Patch-clamp experiments in tracheal myocytes showed that TES also increased ATP- and UTP-induced K+ currents, and this effect was abolished with flutamide (an androgen receptor antagonist). KV channels were involved in this phenomenon, which was demonstrated by inhibition with 4-aminopyridine. RB2 (an antagonist of almost all P2Y receptors except for P2Y2), as well as N-ethylmaleimide and SQ 22,536 (inhibitors of G proteins and adenylyl cyclase, respectively), attenuated the enhancement of the K+ currents induced by TES. Immunofluorescence and immunohistochemistry studies revealed that TES did not modify the expression of P2Y4 receptors or COX-1 and COX-2, while we have demonstrated that this androgen augmented the expression of KV1.2 and KV1.5 channels in ASM. Thus, TES leads to the upregulation of P2Y4 signaling and KV channels in guinea pig ASM, enhancing ATP and UTP relaxation responses, which likely limits the severity of bronchospasm in young males.

Purinergic inhibitory regulation of esophageal smooth muscle is mediated by P2Y receptors and ATP-dependent potassium channels in rats

Purines such as ATP are regulatory transmitters in motility of the gastrointestinal tract. The aims of this study were to propose functional roles of purinergic regulation of esophageal motility. An isolated segment of the rat esophagus was placed in an organ bath, and mechanical responses were recorded using a force transducer. Exogenous application of ATP (10–100 μM) evoked relaxation of the esophageal smooth muscle in a longitudinal direction under the condition of carbachol (1 μM) -induced precontraction. Pretreatment with a non-selective P2 receptor antagonist, suramin (500 μM), and a P2Y receptor antagonist, cibacron blue F3GA (200 μM), inhibited the ATP (100 μM) -induced relaxation, but a P2X receptor antagonist, pyridoxal phosphate-6-azophenyl-2,4-disulfonic acid (50 μM), did not affect it. A blocker of ATP-dependent potassium channels (KATP channels), glibenclamide (200 μM), inhibited the ATP-induced relaxation and application of an opener of KATP channels, nicorandil (50 μM), produced relaxation. The findings suggest that ATP is involved in inhibitory regulation of the longitudinal smooth muscle in the muscularis mucosae of the rat esophagus via activation of P2Y receptors and then opening of KATP channels.

Sex-dependent regulation of mucin gene transcription and airway secretion and mechanics following intra-airway IL-13 in mice with conditional loss of club cell Creb1.

Introduction: Interleukin 13 (IL-13) is an important effector molecule in allergic asthma. IL-13-mediated mucin hypersecretion requires conversion of secretoglobin-positive club cells into goblet cells through suppression of forkhead box A2 (FOXA2) and induction of SAM pointed domain containing ETS transcription factor (SPDEF). IL-13-mediated mucin hypersecretion may also include modulation of purinergic and muscarinic receptors that control basal and stimulated mucin secretion. We recently found that the transcription factor cAMP response element-binding protein (Creb1) inhibits FOXA2 and modulates mucus secretion in mice. Methods: We tested the hypothesis that loss of club cell Creb1 mitigates the pro-mucin effects of IL-13. We challenged male and female mice with conditional loss of club cell Creb1 and wild type littermates with intra-airway IL-13 or vehicle. We also studied human "club cell-like" NCI-H322 cells. Results: Loss of club cell Creb1 augmented IL-13-mediated increases in mRNA for the gel-forming mucins Muc5ac and Muc5b and prevented IL-13-mediated decreases in muscarinic 3 receptor (M3R) mRNA in male airways. In female airways, loss of club cell Creb1 reduced M3R mRNA and significantly blunted IL-13-mediated increases in purinergic receptor P2Y2 (P2ry2) mRNA but did not impact Muc5ac and Muc5b mRNA. Despite changes in mucins and secretion machinery, goblet cell density following cholinergic stimulation was not impacted by loss of club cell Creb1 in either sex. IL-13 treatment decreased basal airway resistance across sexes in mice with loss of club cell Creb1, whereas loss of club cell Creb1 augmented IL-13-mediated increases in airway elastance in response to methacholine. NCI-H322 cells displayed IL-13 signaling components, including IL-13Rα1 and IL-4Rα. Pharmacologic inhibition of CREB reduced IL-13Rα1 mRNA, whereas recombinant CREB decreased IL-4Rα mRNA. Application of IL-13 to NCI-H322 cells increased concentrations of cAMP in a delayed manner, thus linking IL-13 signaling to CREB signaling. Conclusion: These data highlight sex-specific regulation of club cell Creb1 on IL-13-mediated mucin hypersecretion and airway mechanics.

Controversy in cardiology: clopidogrel or acetylsalicylic acid in the treatment of chronic coronary syndromes?

Secondary prevention of patients with chronic coronary syndrome is based on the long-term use of a single anti-aggregating drug which is traditionally represented by acetylsalicylic acid (ASA) in light of the results of studies and meta-analyses which have demonstrated a clear anti-ischaemic efficacy against of an acceptable increase in the risk of bleeding, especially intracranial and gastrointestinal bleeding. The availability of drugs such as clopidogrel, which inhibits platelet activity through the P2Y12 receptor pathway, has called into question this paradigm, also in consideration of the fact that the scientific evidence that supports the use of ASA in secondary prevention is based on dated studies with some limitations. Over the last few years, randomized trials have demonstrated how clopidogrel has an efficacy profile comparable to that of ASA and a safety profile that is sometimes even better. In light of the new evidence, it is therefore legitimate to ask whether in this clinical scenario, ASA should still be considered the drug of choice or whether clopidogrel could represent the preferable alternative.

Extended Clopidogrel Monotherapy vs DAPT in Patients With Acute Coronary Syndromes at High Ischemic and Bleeding Risk

Purinergic receptor P2Y12 (P2Y12) inhibitor monotherapy after a certain period of dual antiplatelet therapy (DAPT) may be an attractive option of maintenance antiplatelet treatment for patients undergoing percutaneous coronary intervention (PCI) who are at both high bleeding and ischemic risk (birisk). To determine if extended P2Y12 inhibitor monotherapy with clopidogrel is superior to ongoing DAPT with aspirin and clopidogrel after 9 to 12 months of DAPT after PCI in birisk patients with acute coronary syndromes (ACS). This was a multicenter, double-blind, placebo-controlled, randomized clinical trial including birisk patients with ACS who had completed 9 to 12 months of DAPT after drug-eluting stent implantation and were free from adverse events for at least 6 months at 101 China centers between February 2018 and December 2020. Study data were analyzed from April 2023 to May 2023. Patients were randomized either to clopidogrel plus placebo or clopidogrel plus aspirin for an additional 9 months. The primary end point was Bleeding Academic Research Consortium (BARC) types 2, 3, or 5 bleeding 9 months after randomization. The key secondary end point was major adverse cardiac and cerebral events (MACCE; the composite of all-cause death, myocardial infarction, stroke or clinically driven revascularization). The primary end point was tested for superiority, and the MACCE end point was tested for sequential noninferiority and superiority. A total of 7758 patients (mean [SD] age, 64.8 [9.0] years; 4575 male [59.0%]) were included in this study. The primary end point of BARC types 2, 3, or 5 bleeding occurred in 95 of 3873 patients (2.5%) assigned to clopidogrel plus placebo and 127 of 3885 patients (3.3%) assigned to clopidogrel plus aspirin (hazard ratio [HR], 0.75; 95% CI, 0.57-0.97; difference, -0.8%; 95% CI, -1.6% to -0.1%; P = .03). The incidence of MACCE was 2.6% (101 of 3873 patients) in the clopidogrel plus placebo group and 3.5% (136 of 3885 patients) in the clopidogrel plus aspirin group (HR, 0.74; 95% CI, 0.57-0.96; difference, -0.9%; 95% CI, -1.7% to -0.1%; P < .001 for noninferiority; P = .02 for superiority). Among birisk patients with ACS who completed 9 to 12 months of DAPT after drug-eluting stent implantation and were free from adverse events for at least 6 months before randomization, an extended 9-month clopidogrel monotherapy regimen was superior to continuing DAPT with clopidogrel in reducing clinically relevant bleeding without increasing ischemic events. ClinicalTrials.gov Identifier: NCT03431142.

Microglial P2Y6 calcium signaling promotes phagocytosis and shapes neuroimmune responses in epileptogenesis

Microglial calcium signaling is rare in a baseline state but strongly engaged during early epilepsy development. The mechanism(s) governing microglial calcium signaling are not known. By developing an invivo uridine diphosphate (UDP) fluorescent sensor, GRABUDP1.0, we discovered that UDP release is a conserved response to seizures and excitotoxicity across brain regions. UDP can signal through the microglial-enriched P2Y6 receptor to increase calcium activity during epileptogenesis. P2Y6 calcium activity is associated with lysosome biogenesis and enhanced production of NF-κB-related cytokines. In the hippocampus, knockout of the P2Y6 receptor prevents microglia from fully engulfing neurons. Attenuating microglial calcium signaling through calcium extruder ("CalEx") expression recapitulates multiple features of P2Y6 knockout, including reduced lysosome biogenesis and phagocytic interactions. Ultimately, P2Y6 knockout mice retain more CA3 neurons and better cognitive task performance during epileptogenesis. Our results demonstrate that P2Y6 signaling impacts multiple aspects of myeloid cell immune function during epileptogenesis.

Inhibition of TNFalpha Release by Purine Nucleosides in a Human Monocyte-derived Microglial Model Exhibits Apparent Insensitivity to Adenosine, P2X, and P2Y Receptor Antagonism (P5-14.020)

Inhibition of TNFalpha Release by Purine Nucleosides in a Human Monocyte-derived Microglial Model Exhibits Apparent Insensitivity to Adenosine, P2X, and P2Y Receptor Antagonism (P5-14.020)

Ticagrelor alone versus ticagrelor plus aspirin from month 1 to month 12 after percutaneous coronary intervention in patients with acute coronary syndromes (ULTIMATE-DAPT): a randomised, placebo-controlled, double-blind clinical trial

Following percutaneous coronary intervention with stent placement to treat acute coronary syndromes, international clinical guidelines generally recommend dual antiplatelet therapy with aspirin plus a P2Y12 receptor inhibitor for 12 months to prevent myocardial infarction and stent thrombosis. However, data on single antiplatelet therapy with a potent P2Y12 inhibitor earlier than 12 months after percutaneous coronary intervention for patients with an acute coronary syndrome are scarce. The aim of this trial was to assess whether the use of ticagrelor alone, compared with ticagrelor plus aspirin, could reduce the incidence of clinically relevant bleeding events without an accompanying increase in major adverse cardiovascular or cerebrovascular events (MACCE). In this randomised, placebo-controlled, double-blind clinical trial, patients aged 18 years or older with an acute coronary syndrome who completed the IVUS-ACS study and who had no major ischaemic or bleeding events after 1-month treatment with dual antiplatelet therapy were randomly assigned to receive oral ticagrelor (90 mg twice daily) plus oral aspirin (100 mg once daily) or oral ticagrelor (90 mg twice daily) plus a matching oral placebo, beginning 1 month and ending at 12 months after percutaneous coronary intervention (11 months in total). Recruitment took place at 58 centres in China, Italy, Pakistan, and the UK. Patients were required to remain event-free for 1 month on dual antiplatelet therapy following percutaneous coronary intervention with contemporary drug-eluting stents. Randomisation was done using a web-based system, stratified by acute coronary syndrome type, diabetes, IVUS-ACS randomisation, and site, using dynamic minimisation. The primary superiority endpoint was clinically relevant bleeding (Bleeding Academic Research Consortium [known as BARC] types 2, 3, or 5). The primary non-inferiority endpoint was MACCE (defined as the composite of cardiac death, myocardial infarction, ischaemic stroke, definite stent thrombosis, or clinically driven target vessel revascularisation), with an expected event rate of 6·2% in the ticagrelor plus aspirin group and an absolute non-inferiority margin of 2·5 percentage points between 1 month and 12 months after percutaneous coronary intervention. The two co-primary endpoints were tested sequentially; the primary superiority endpoint had to be met for hypothesis testing of the MACCE outcome to proceed. All principal analyses were assessed in the intention-to-treat population. This trial is registered with ClinicalTrials.gov, NCT03971500, and is completed. Between Sept 21, 2019, and Oct 27, 2022, 3400 (97·0%) of the 3505 participants in the IVUS-ACS study were randomly assigned (1700 patients to ticagrelor plus aspirin and 1700 patients to ticagrelor plus placebo). 12-month follow-up was completed by 3399 (>99·9%) patients. Between month 1 and month 12 after percutaneous coronary intervention, clinically relevant bleeding occurred in 35 patients (2·1%) in the ticagrelor plus placebo group and in 78 patients (4·6%) in the ticagrelor plus aspirin group (hazard ratio [HR] 0·45 [95% CI 0·30 to 0·66]; p<0·0001). MACCE occurred in 61 patients (3·6%) in the ticagrelor plus placebo group and in 63 patients (3·7%) in the ticagrelor plus aspirin group (absolute difference -0·1% [95% CI -1·4% to 1·2%]; HR 0·98 [95% CI 0·69 to 1·39]; pnon-inferiority<0·0001, psuperiority=0·89). In patients with an acute coronary syndrome who had percutaneous coronary intervention with contemporary drug-eluting stents and remained event-free for 1 month on dual antiplatelet therapy, treatment with ticagrelor alone between month 1 and month 12 after the intervention resulted in a lower rate of clinically relevant bleeding and a similar rate of MACCE compared with ticagrelor plus aspirin. Along with the results from previous studies, these findings show that most patients in this population can benefit from superior clinical outcomes with aspirin discontinuation and maintenance on ticagrelor monotherapy after 1 month of dual antiplatelet therapy. The Chinese Society of Cardiology, the National Natural Scientific Foundation of China, and the Jiangsu Provincial & Nanjing Municipal Clinical Trial Project. For the Mandarin translation of the abstract see Supplementary Materials section.

An adapted protocol to derive microglia from stem cells and its application in the study of CSF1R-related disorders

BackgroundInduced pluripotent stem cell-derived microglia (iMGL) represent an excellent tool in studying microglial function in health and disease. Yet, since differentiation and survival of iMGL are highly reliant on colony-stimulating factor 1 receptor (CSF1R) signaling, it is difficult to use iMGL to study microglial dysfunction associated with pathogenic defects in CSF1R.MethodsSerial modifications to an existing iMGL protocol were made, including but not limited to changes in growth factor combination to drive microglial differentiation, until successful derivation of microglia-like cells from an adult-onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP) patient carrying a c.2350G > A (p.V784M) CSF1R variant. Using healthy control lines, the quality of the new iMGL protocol was validated through cell yield assessment, measurement of microglia marker expression, transcriptomic comparison to primary microglia, and evaluation of inflammatory and phagocytic activities. Similarly, molecular and functional characterization of the ALSP patient-derived iMGL was carried out in comparison to healthy control iMGL.ResultsThe newly devised protocol allowed the generation of iMGL with enhanced transcriptomic similarity to cultured primary human microglia and with higher scavenging and inflammatory competence at ~ threefold greater yield compared to the original protocol. Using this protocol, decreased CSF1R autophosphorylation and cell surface expression was observed in iMGL derived from the ALSP patient compared to those derived from healthy controls. Additionally, ALSP patient-derived iMGL presented a migratory defect accompanying a temporal reduction in purinergic receptor P2Y12 (P2RY12) expression, a heightened capacity to internalize myelin, as well as heightened inflammatory response to Pam3CSK4. Poor P2RY12 expression was confirmed to be a consequence of CSF1R haploinsufficiency, as this feature was also observed following CSF1R knockdown or inhibition in mature control iMGL, and in CSF1RWT/KO and CSF1RWT/E633K iMGL compared to their respective isogenic controls.ConclusionsWe optimized a pre-existing iMGL protocol, generating a powerful tool to study microglial involvement in human neurological diseases. Using the optimized protocol, we have generated for the first time iMGL from an ALSP patient carrying a pathogenic CSF1R variant, with preliminary characterization pointing toward functional alterations in migratory, phagocytic and inflammatory activities.Graphical

Individual trombocity reactivity in hematuria associated with nephrolitiasis: the role of purinergic signalisation in the treatment of nesteroid protective preparations

Aim of the study was to establish the significance of TR-receptor, P2X1-receptor and P2Y-receptor synergism for the efficiency of TC aggregation in patients with different sensitivity to non-selective NSAIDs, which will allow us to approach an understanding the causes of the variability of hematuria associated with NLT. Material and methods. The study was prospective and included 60 patients with nephrolithiasis who were treated with high doses of NSAIDs for analgesia. The cohort of patients was divided into two groups: with effective (group 1. n=30) and ineffective (group 2. n=30) COX inhibition. The severity of hematuria was assessed during 7 days of drug therapy. The activity of TR receptors, purine P2X1- and P2Y- receptors of platelets (Tc) was analysed by turbidimetric method on ChronoLog analyser (USA). Agonists (ATP, ADP and Arachidonic acid) were used at EC50 and EC10 concentrations. Results. In the 1 group of patients, hyporeactivity of the TP receptor was established within 72 hours, which was restored to the level of normoreactivity on the 5th day of therapy. Optimal modulation of the compensatory reaction of Pl in response to hematuria was provided through the synergism of purine P2X1 and P2Y receptors. Optimal modulation of the compensatory reaction of Tc in response to hematuria was provided through the synergism of purine P2X1 and P2Y receptors. On the 7th day, a residual level of COX activity was reached, while intracellular signaling associated with stimulation of the TP receptor and purine P2 receptors did not provide the limitation of hematuria. In the 2 group, when patients were prescribed NSAIDs for 7 days, hyperreactivity of the TP receptor, P2 receptors and a stable level of microhematuria remained. In the case of COX resistance and increased production of TxA2, the maximum increase in proaggregant Tc activity was ensured through the stereotypical mechanism of intracellular signaling associated with stimulation of P2Y receptors (through Gi- and Gq- proteins) and the TP receptor (through Gq- and Gq12/13- proteins). Conclusion. Further study of the mechanisms of crosstalk signaling pathways with different COX activity will allow us to establish promising directions for pharmacological correction aimed at preventing hematuria and ensuring hemostasis in nephrolithiasis.

Platelet Activation Pathways Controlling Reversible Integrin αIIbβ3 Activation.

Background Agonist-induced platelet activation, with the integrin αIIbβ3 conformational change, is required for fibrinogen binding. This is considered reversible under specific conditions, allowing a second phase of platelet aggregation. The signaling pathways that differentiate between a permanent or transient activation state of platelets are poorly elucidated. Objective To explore platelet signaling mechanisms induced by the collagen receptor glycoprotein VI (GPVI) or by protease-activated receptors (PAR) for thrombin that regulate time-dependent αIIbβ3 activation. Methods Platelets were activated with collagen-related peptide (CRP, stimulating GPVI), thrombin receptor-activating peptides, or thrombin (stimulating PAR1 and/or 4). Integrin αIIbβ3 activation and P-selectin expression was assessed by two-color flow cytometry. Signaling pathway inhibitors were applied before or after agonist addition. Reversibility of platelet spreading was studied by microscopy. Results Platelet pretreatment with pharmacological inhibitors decreased GPVI- and PAR-induced integrin αIIbβ3 activation and P-selectin expression in the target order of protein kinase C (PKC) > glycogen synthase kinase 3 > β-arrestin > phosphatidylinositol-3-kinase. Posttreatment revealed secondary αIIbβ3 inactivation (not P-selectin expression), in the same order, but this reversibility was confined to CRP and PAR1 agonist. Combined inhibition of conventional and novel PKC isoforms was most effective for integrin closure. Pre- and posttreatment with ticagrelor, blocking the P2Y 12 adenosine diphosphate (ADP) receptor, enhanced αIIbβ3 inactivation. Spreading assays showed that PKC or P2Y 12 inhibition provoked a partial conversion from filopodia to a more discoid platelet shape. Conclusion PKC and autocrine ADP signaling contribute to persistent integrin αIIbβ3 activation in the order of PAR1/GPVI > PAR4 stimulation and hence to stabilized platelet aggregation. These findings are relevant for optimization of effective antiplatelet treatment.

The Effect of Clopidogrel Treatment on Osseointegration of Titanium Implants: A Histomorphometric Study in Rabbits.

To evaluate the effect of continuous perioperative clopidogrel treatment on the osseointegration of titanium implants. A total of 32 New Zealand rabbits were randomly divided between two groups: a clopidogrel group (n = 16) and a control group (n = 16). For 1 week prior to the surgical placement of a titanium implant in their medial femoral condyle, rabbits in the clopidogrel group received 3 mg/kg of clopidogrel daily, and the control group received only the vehicle. This treatment was continued for another 6 weeks postoperatively. At 6 weeks, the rabbits were euthanized and postmortem histologic and histomorphometric evaluation of the implants was performed. The surgical procedures and postoperative period were uneventful and well tolerated by all animals without any surgical wound dehiscence, signs of infection, or other complication. No implant failure was observed in any of the groups. Histomorphometric analysis showed that bone-to-implant contact (BIC) was 48.77% for the clopidogrel group and 34.65% for the control group, with statistically significant difference between them (P < .001). Moreover, clopidogrel group had significantly greater bone tissue density (40.52% vs 28.74%, respectively; P <.001) and mean trabecular thickness (284.7 μm vs 180.7 μm, respectively; P < .001) in proximity to the implant surface than the control group, while the mean trabecular number had no difference between groups (1.56 vs 1.60, respectively; P = .961). The present study showed that continuous clopidogrel treatment does not negatively affect osseointegration, but rather promotes it in terms of BIC and bone density around the titanium implants. Further studies on the effect of the P2Y12 receptor and its antagonists on peri-implant bone homeostasis may provide useful information or applications for long-term success of dental implant therapy.