Purinergic P2Y Receptors Research Articles

Renal Na+ excretion consequent to pharmacogenetic activation of Gq-DREADD in principal cells.

Stimulation of metabotropic Gq-coupled purinergic P2Y2 receptors decreases activity of the epithelial Na+ channel (ENaC) in renal principal cells of the distal nephron. The physiological consequences of P2Y2 receptor signaling disruption in the P2Y2 receptor knockout mouse are decreased Na+ excretion and increased arterial blood pressure. However, because of the global nature of this knockout model, the quantitative contribution of ENaC and distal nephron compared with that of upstream renal vascular and tubular elements to changes in urinary excretion and arterial blood pressure is obscure. Moreover, it is uncertain whether stimulation of P2Y2 receptor inhibition of ENaC is sufficient to drive renal (urinary) Na+ excretion (UNaV). Here, using a pharmacogenetic approach and selective agonism of the P2Y2 receptor, we test the sufficiency of targeted stimulation of Gq signaling in principal cells of the distal nephron and P2Y2 receptors to increase UNaV. Selective stimulation of the P2Y2 receptor with the ligand MRS2768 decreased ENaC activity in freshly isolated tubules (as assessed by patch-clamp electrophysiology) and increased UNaV (as assessed in metabolic cages). Similarly, selective agonism of hM3Dq-designer receptors exclusively activated by designer drugs (DREADD) restrictively expressed in principal cells of the distal nephron with clozapine- N-oxide decreased ENaC activity and, consequently, increased UNaV. Clozapine- N-oxide, when applied to control littermates, failed to affect ENaC and UNaV. This study represents the first use of pharmacogenetic (DREADD) technology in the renal tubule and demonstrated that selective activation of the P2Y2 receptor and Gq signaling in principal cells is sufficient to promote renal salt excretion.

GPR17 receptor modulators and their therapeutic implications: review of recent patents

ABSTRACTIntroduction: The GPR17 receptor, phylogenetically related to both purinergic P2Y and CysLT receptors, is mainly expressed in the CNS and, in general, in organs that can typically undergo ischemic damage. This receptor is involved in various pathologies including stroke, brain and spinal cord trauma, multiple sclerosis and in all diseases characterized by neuronal and myelin dysfunction. Therefore, there is a strong needed to identify molecules capable of binding specifically to GPR17 receptors.Areas covered: The review provides a summary of patents, published between 2009 and 2018, on chemicals and biologics and their clinical use. In this work, information is reported about the representative structures and biological activity of recently developed GPR17 receptor ligands.Expert opinion: The GPR17 receptor is an enigmatic receptor and an interesting therapeutic target in a variety of brain disorders and demyelinating diseases such as multiple sclerosis, stroke, schizophrenia, and depression. The modulation of this receptor could also be potentially useful in obesity treatment. Unfortunately, so far, there are no compounds under investigation in clinical trials but many researchers and companies are investing in the discovery of future potential GPR17 receptor drugs.

Association of G-protein coupled purinergic receptor P2Y2 with ischemic stroke in a Han Chinese population of North China.

The G-protein-coupled purinergic receptor P2Y2 (P2RY2) plays an important role in the mechanism of atherosclerosis, which is relevant to ischemic stroke. This retrospective case-control study aimed to assess the relationship between P2RY2 gene polymorphisms and ischemic stroke risk in the northern Han Chinese population. In this study, clinical data and peripheral blood specimens were collected from 378 ischemic stroke patients and 344 controls. The ischemic stroke participants were recruited from the First Affiliated Hospital of China Medical University and the First Affiliated Hospital of Liaoning Medical University. The controls were recruited from the Health Check Center at the First Affiliated Hospital of China Medical University. Ischemic stroke patients were divided into two subgroups according to the Trial of ORG 10172 in Acute Stroke Treatment (TOAST) classification: large-artery atherosclerosis (n = 178) and small-artery occlusion (n = 200) strokes. All subjects were genotyped for three single nucleotide polymorphisms (rs4944831, rs1783596, and rs4944832) in the P2RY2 gene using peripheral venous blood samples. The distribution of the dominant rs4944832 phenotype (GG vs. GA+AA) differed significantly between small-artery occlusion patients and control subjects (odds ratio (OR) = 1.720, 95% confidence interval (CI): 1.203-2.458, P < 0.01). Multivariable logistic regression analysis revealed that the GG genotype of rs4944832 was significantly more prevalent in small-artery occlusion patients than in control subjects (OR = 1.807, 95% CI: 1.215-2.687, P < 0.01). The overall distribution of the haplotype established by rs4944831-rs1783596-rs4944832 was significantly different between ischemic stroke patients and controls (P < 0.01). In ischemic stroke patients, the frequency of the G-C-G haplotype was significantly higher than in control subjects (P = 0.028), whereas the frequency of the T-C-A haplotype was lower than in control subjects (P = 0.047). These results indicate that the G-C-G haplotype of P2RY2 is a susceptibility haplotype for ischemic stroke. In addition, the GG genotype of rs4944832 may be associated with the development of small-artery occlusion in the northern Han Chinese population. The study protocol was approved by the Ethics Committee of the First Affiliated Hospital of China Medical University on February 20, 2012 (No. 2012-38-1) and the First Affiliated Hospital of Liaoning Medical University, China, on March 1, 2013 (No. 2013-03-1). All participants gave their informed consent. This trial was registered with the ISRCTN Registry (ISRCTN11439124) on October 24, 2018. Protocol version (1.0).

Studies on the GFP-tagged receptor or β-arrestin2 in U2OS cells reveal two separate signaling pathways of purinergic P2Y1 receptors

The expression of fusion proteins in recombinant cell lines.

BLOOD PLATELETS AS ACTIVATORS AND REGULATORS OF INFLAMMATORY AND IMMUNE REACTIONS. PART 1. BASIC CHARACTERISTICS OF PLATELETS AS INFLAMMATORY CELLS

Platelets are the smallest blood cells, and yet their total volume and surface area exceed those of all types of leukocytes combined. Platelets are produced by the bone marrow megakaryocytes and megakaryocytes in the lung microvessels. Approximately 50% of all platelets are produced in the lungs, which makes it possible to characterize them as the main site for the production of platelets. In small circuit of blood circulation, there are approximately 30% more platelets than in large circuit. This “excess” of platelets is necessary for the stabilization of the endothelial barrier of the lung vessels regulated by the platelet mediator sphingosine-1-phosphate, a regulator of tight junctions of endothelial cells. The circulating platelets have an amazing ability to “bud” new pro- and pre-platelets, giving rise to new platelets. The removal of platelets from circulation proceeds via their phagocytosis by spleen macrophages (if platelets are covered with IgG or are bound to immune complexes), or Kupffer liver cells and hepatocytes (if platelets have incomplete glycans or desialated proteins). In homeostatic conditions, most of the platelets are removed in liver. Platelet clearance in bacterial infections and sepsis is accelerated because of the activity of bacterial sialidases. Recognition of desialized platelet structures is carried out by the liver cells through the Asgr receptor. Despite DNA absence, the platelets are able to synthesize proteins at mRNAs that are present in majority of platelets. Activation of platelets leads to aggregation and exocytosis of the granule contents, and production of immunomodulating molecules. However, activation of platelets may be incomplete and has various consequences. In a non-classical activation model, platelets can release microparticles that contain about 600 different proteins. About 75% of microparticles in the blood of healthy donors are derived from platelets. Like as immune system cells, platelets are activated by numerous endogenous ligands (alarms), including ADP and ATP, which bind to purinergic receptors P2Y1, P2Y12 andP2X1. Platelets accumulate and retain 99% of the serotonin stored in the body. The platelets contribute to induction of inflammation by releasing proinflammatory cytokines, chemokines, and lipid mediators. In addition, platelets are the source of enzymes that accomplish the capacities of neutrophils and endothelium for production of anti-inflammatory lipid mediators that contribute to tissue repair following acute phase of inflammation.

Characterization of cysteinyl leukotriene-related receptors and their interactions in a mouse model of asthma

Identification of the characterization of cysteinyl leukotrienes receptor (CysLTRs) could facilitate our understanding of these receptors’ role in asthma. We aimed to investigate the localization and interactions of CysLTRs using a mouse model of asthma. BALB/c mice were administered ovalbumin (OVA) to induce allergic asthma. Some mice were administered the antagonists of CysLTR1, CysLTR2, and purinergic receptor P2Y12 (P2Y12R) (montelukast, HAMI 3379 and clopidogrel, respectively). The expression levels of CysLTR1, CysLTR2, and P2Y12R on lung tissues and inflammatory cells were evaluated by western blot, flow cytometry, and immunochemistry. CysLTR1 and P2Y12R were significantly up-regulated in lung tissues (P < 0.05 for each) from mouse after being sensitized and challenged with OVA (OVA/OVA). The ratio of CysLTR1: CysLTR2: P2Y12R in lungs of negative control (NC) mice was shifted from 1:0.43:0.35 to 1:0.65:1.34 in OVA/OVA mice. Montelukast significantly diminished the up-regulation of CysLTR1, CysLTR2, and P2Y12R (P < 0.05 for each), while the effects of HAMI 3379 and clopidogrel were predominant on the expression of CysLTR2 and P2Y12R, respectively. Montelukast predominantly diminished the cell count, while clopidogrel potently inhibited the release of interleukin (IL)-4, IL-5, and IL-13. Our study demonstrated the interactions between CysLTRs, thereby highlighting the potential synergistic effects of CysLTR antagonists in asthma treatment.

Microglia in the RVLM of SHR have reduced P2Y12R and CX3CR1 expression, shorter processes, and lower cell density.

The RVLM of spontaneously hypertensive rats (SHR) contains over-active C1 neurons, which model the pathology of essential hypertension. Hypertension involves chronic low-grade neuroinflammation. Inflammation in the brain is produced and maintained primarily by microglia. We assessed microglial gene expression (P2Y12R and CX3CR1) and morphology in the RVLM of SHR compared to normotensive Wistar-Kyoto rats (WKY). The gene expression of the metabotropic purinergic receptor P2Y12 and the fractalkine receptor CX3CR1 was downregulated in the RVLM of SHR compared to WKY (by 37.3% and 30.9% respectively). P2Y12R and CX3CR1 are required for normal microglial function, and reduced P2Y12R expression is associated with changes in microglial activity. Histological analysis showed a 22.9% reduction in microglial cell density, along with 18.7% shorter microglial processes, a phenotypic indicator of activation, in the RVLM of SHR compared to WKY. These results indicate a subtle loss of function, or a mild state of inflammation, in the RVLM microglia of SHR.

Synthesis, characterization, molecular docking, analgesic, antiplatelet and anticoagulant effects of dibenzylidene ketone derivatives

In this study dibenzylidene ketone derivatives (2E,5E)-2-(4-methoxybenzylidene)-5-(4-nitrobenzylidene) cyclopentanone (AK-1a) and (1E,4E)-4-(4-nitrobenzylidene)-1-(4-nitrophenyl) oct-1-en-3-one (AK-2a) were newly synthesized, inspired from curcuminoids natural origin. Novel scheme was used for synthesis of AK-1a and AK-2a. The synthesized compounds were characterized by spectroscopic techniques. AK-1a and AK-2a showed high computational affinities (E-value > − 9.0 kcal/mol) against cyclooxygenase-1, cyclooxygenase-2, proteinase-activated receptor 1 and vitamin K epoxide reductase. AK-1a and AK-2a showed moderate docking affinities (E-value > − 8.0 kcal/mol) against mu receptor, kappa receptor, delta receptor, human capsaicin receptor, glycoprotein IIb/IIIa, prostacyclin receptor I2, antithrombin-III, factor-II and factor-X. AK-1a and AK-2a showed lower affinities (E-value > − 7.0 kcal/mol) against purinoceptor-3, glycoprotein-VI and purinergic receptor P2Y12. In analgesic activity, AK-1a and AK-2a decreased numbers of acetic acid-induced writhes (P < 0.001 vs. saline group) in mice. AK-1a and AK-2a significantly prolonged the latency time of mice (P < 0.05, P < 0.01 and P < 0.001 vs. saline group) in hotplate assay. AK-1a and AK-2a inhibited arachidonic acid and adenosine diphosphate induced platelet aggregation with IC50 values of 65.2, 37.7, 750.4 and 422 µM respectively. At 30, 100, 300 and 1000 µM concentrations, AK-1a and AK-2a increased plasma recalcification time (P < 0.001 and P < 0.001 vs. saline group) respectively. At 100, 300 and 1000 µg/kg doses, AK-1a and AK-2a effectively prolonged bleeding time (P < 0.001 and P < 0.01 vs. saline group) respectively. Thus in-silico, in-vitro and in-vivo investigation of AK-1a and AK-2a reports their analgesic, antiplatelet and anticoagulant actions.

The Regulation of Skin Fibrosis in Systemic Sclerosis by Extracellular ATP via P2Y2 Purinergic Receptor

Tissue injury/hypoxia and oxidative stress induced-extracellular adenosine triphosphate (ATP) can act as damage-associated molecular pattern molecules, which initiate inflammatory response. Our objective was to elucidate the role of extracellular ATP in skin fibrosis in systemic sclerosis (SSc). We identified that hypoxia enhanced ATP release and that extracellular ATP enhanced IL-6 production more significantly in SSc fibroblasts than in normal fibroblasts. There were no significant differences of P2X and P2Y receptor expression levels between normal and SSc fibroblasts. Nonselective P2 receptor antagonist and selective P2Y2 receptor antagonists, kaempferol and AR-C118925XX, significantly inhibited ATP-induced IL-6 production and phosphorylation of p38 in SSc fibroblasts. ATP-induced IL-6 production was significantly inhibited by p38 inhibitors, SB203580, and doramapimod. Collagen type I production in SSc fibroblasts by ATP-induced IL-6/IL-6 receptor trans-signaling was inhibited by kaempferol and SB203580. The amount of ATP in bleomycin-treated skin was increased, and administration of AR-C118925XX significantly inhibited bleomycin-induced dermal fibrosis in mice. These results suggest that vasculopathy-induced hypoxia and oxidative stress might enhance ATP release in the dermis in SSc and that extracellular ATP-induced phosphorylation of p38 via P2Y2 receptor might enhance IL-6 and collagen type I production in SSc fibroblasts. P2Y2 receptor antagonist therapy could be a treatment for skin sclerosis in patients with SSc.

Purinergic receptor Y2 (P2Y2)- dependent VCAM-1 expression promotes immune cell infiltration in metabolic syndrome.

Sterile inflammation of visceral fat, provoked by dying adipocytes, links the metabolic syndrome to cardiovascular disease. Danger-associated molecular patterns, such as adenosine triphosphate (ATP), are released by activated or dying cells and orchestrate leukocyte infiltration and inflammation via the purinergic receptor P2Y2. The gene expression of ATP receptor P2Y2 did not change in several tissues in the course of obesity, but was increased within epididymal fat. Adipose tissue from P2Y 2-/- mice consuming high-fat diet (HFD) contained less crown-like structures with a reduced frequency of adipose tissue macrophages (ATMs). This was likely due to decreased leukocyte migration because of missing VCAM-1 exposition on P2Y2 deficient hypertrophic adipose tissue endothelial cells. Accordingly, P2Y 2-/- mice showed blunted traits of the metabolic syndrome: they gained less weight compared to P2Y 2+/+ controls, while intake of food and movement behaviour remained unchanged. Liver and adipose tissue were smaller in P2Y 2-/- animals. Insulin tolerance testing (ITT) performed in obese P2Y 2-/- mice revealed a better insulin sensitivity as well as lower plasma C-peptide and cholesterol levels. We demonstrate that interfering with somatic P2Y2 signalling prevents excessive immune cell deposition in diet-induced obesity (DIO), both attenuating adipose tissue inflammation and ameliorating the metabolic phenotype. Thus, blocking the P2Y2 cascade may be a promising strategy to limit metabolic disease and its sequelae.

Dual effects of human neutrophil peptides in a mouse model of pneumonia and ventilator-induced lung injury

BackgroundPneumonia is a major cause of high morbidity and mortality in critically illness, and frequently requires support with mechanical ventilation. The latter can lead to ventilator-induced lung injury characterized by neutrophil infiltration. The cationic human neutrophil peptides (HNP) stored in neutrophils can kill microorganisms, but excessive amount of HNP released during phagocytosis may contribute to inflammatory responses and worsen lung injury. Based on our previous work, we hypothesized that blocking the cell surface purinergic receptor P2Y6 will attenuate the HNP-induced inflammatory responses while maintaining their antimicrobial activity in pneumonia followed by mechanical ventilation.MethodsPlasma HNP levels were measured in patients with pneumonia who received mechanical ventilation and in healthy volunteers. FVB littermate control and HNP transgenic (HNP+) mice were randomized to receive P. aeruginosa intranasally. The P2Y6 antagonist (MRS2578) or vehicle control was given after P. aeruginosa instillation. Additional mice underwent mechanical ventilation at either low pressure (LP) or high pressure (HP) ventilation 48 h after pneumonia, and were observed for 24 h.ResultsPlasma HNP concentration increased in patients with pneumonia as compared to healthy subjects. The bacterial counts in the bronchoalveolar lavage fluid (BALF) were lower in HNP+ mice than in FVB mice 72 h after P. aeruginosa instillation. However, upon receiving HP ventilation, HNP+ mice had higher levels of cytokines and chemokines in BALF than FVB mice. These inflammatory responses were attenuated by the treatment with MRS2578 that did not affect the microbial effects of HNP.ConclusionsHNP exerted dual effects by exhibiting antimicrobial activity in pneumonia alone condition while enhancing inflammatory responses in pneumonia followed by HP mechanical ventilation. Blocking P2Y6 can attenuate the inflammation without affecting the antibacterial property of HNP. The P2Y6 receptor may be a novel therapeutic target in attenuation of the leukocyte-mediated excessive host responses in inflammatory lung diseases.

Piezo1 and Gq/G11 promote endothelial inflammation depending on flow pattern and integrin activation.

The vascular endothelium is constantly exposed to mechanical forces, including fluid shear stress exerted by the flowing blood. Endothelial cells can sense different flow patterns and convert the mechanical signal of laminar flow into atheroprotective signals, including eNOS activation, whereas disturbed flow in atheroprone areas induces inflammatory signaling, including NF-κB activation. How endothelial cells distinguish different flow patterns is poorly understood. Here we show that both laminar and disturbed flow activate the same initial pathway involving the mechanosensitive cation channel Piezo1, the purinergic P2Y2 receptor, and Gq/G11-mediated signaling. However, only disturbed flow leads to Piezo1- and Gq/G11-mediated integrin activation resulting in focal adhesion kinase-dependent NF-κB activation. Mice with induced endothelium-specific deficiency of Piezo1 or Gαq/Gα11 show reduced integrin activation, inflammatory signaling, and progression of atherosclerosis in atheroprone areas. Our data identify critical steps in endothelial mechanotransduction, which distinguish flow pattern-dependent activation of atheroprotective and atherogenic endothelial signaling and suggest novel therapeutic strategies to treat inflammatory vascular disorders such as atherosclerosis.

A Tyrosine Switch on NEDD4-2 E3 Ligase Transmits GPCR Inflammatory Signaling

SUMMARYUbiquitination is essential for protein degradation and signaling and pivotal to many physiological processes. Ubiquitination of a subset of G-protein-coupled receptors (GPCRs) by the E3 ligase NEDD4–2 is required for p38 activation, but how GPCRs activate NEDD4–2 to promote ubiquitinmediated signaling is not known. Here, we report that the GPCR protease-activated receptor-1 (PAR1) stimulates c-Src-mediated tyrosine phosphorylation and activation of NEDD4–2 to promote p38 signaling and endothelial barrier disruption. Using mass spectrometry, we identified a unique phosphorylated tyrosine (Y)-485 within the 2,3-linker peptide between WW domain 2 and 3 of NEDD4–2 in agonist-stimulated cells. Mutation of NEDD4–2 Y485 impaired E3 ligase activity and failed to rescue PAR1-stimulated p38 activation and endothelial barrier permeability. The purinergic P2Y1 receptor also required c-Src and NEDD4–2 tyrosine phosphorylation for p38 activation. These studies reveal a novel role for c-Src in GPCR-induced NEDD4–2 activation, which is critical for driving ubiquitin-mediated p38 inflammatory signaling.

Postnatal Restriction of Activity-Induced Ca2+ Responses to Schwann Cells at the Neuromuscular Junction Are Caused by the Proximo-Distal Loss of Axonal Synaptic Vesicles during Development.

Terminal or perisynaptic Schwann cells (TPSCs) are nonmyelinating, perisynaptic glial cells at the neuromuscular junction (NMJ) that respond to neural activity by increasing intracellular calcium (Ca2+) and regulate synaptic function. The onset of activity-induced TPSC Ca2+ responses, as well as whether axonal Schwann cells (ASCs) along the nerve respond to nerve stimulation during development, is unknown. Here, we show that phrenic nerve stimulation in developing male and female mice elicited Ca2+ responses in both ASCs and TPSCs at embryonic day 14. ASC responses were lost in a proximo-distal gradient over time, but could continue to be elicited by bath application of neurotransmitter, suggesting that a loss of release rather than a change in ASC competence accounted for this response gradient. Similar to those of early postnatal TPSCs, developing ASC/TPSC responses were mediated by purinergic P2Y1 receptors. The loss of ASC Ca2+ responses was correlated to the proximo-distal disappearance of synaptophysin immunoreactivity and synaptic vesicles in phrenic axons. Accordingly, developing ASC Ca2+ responses were blocked by botulinum toxin. Interestingly, the loss of ASC Ca2+ responses was also correlated to the proximo-distal development of myelination. Finally, compared with postnatal TPSCs, neonatal TPSCs and ASCs displayed Ca2+ signals in response to lower frequencies and shorter durations of nerve stimulation. Together, these results with GCaMP3-expressing Schwann cells provide ex vivo evidence that both axons and presynaptic terminals initially exhibit activity-induced vesicular release of neurotransmitter, but that the subsequent loss of axonal synaptic vesicles accounts for the postnatal restriction of vesicular release to the NMJ.SIGNIFICANCE STATEMENT Neural activity regulates multiple aspects of development, including myelination. Whether the excitation of developing neurons in vivo results in the release of neurotransmitter from both axons and presynaptic terminals is unclear. Here, using mice expressing the genetically encoded calcium indicator GCaMP3 in Schwann cells, we show that both terminal/perisynaptic Schwann cells at the diaphragm neuromuscular junction and axonal Schwann cells along the phrenic nerve exhibit activity-induced calcium responses early in development, mediated by the vesicular release of ATP from the axons of motor neurons acting on P2Y1 receptors. These ex vivo findings corroborate classic in vitro studies demonstrating transmitter release by developing axons, and thus represent a tool to study the mechanisms and significance of this process during embryonic development.

The inhibitory role of purinergic P2Y receptor on Mg2+ transport across intestinal epithelium-like Caco-2 monolayer.

The mechanism of proton pump inhibitors (PPIs) suppressing intestinal Mg2+ uptake is unknown. The present study aimed to investigate the role of purinergic P2Y receptors in the regulation of Mg2+ absorption in normal and omeprazole-treated intestinal epithelium-like Caco-2 monolayers. Omeprazole suppressed Mg2+ transport across Caco-2 monolayers. An agonist of the P2Y2 receptor, but not the P2Y4 or P2Y6 receptor, suppressed Mg2+ transport across control and omeprazole-treated monolayers. Omeprazole enhanced P2Y2 receptor expression in Caco-2 cells. Forskolin and P2Y2 receptor agonist markedly enhanced apical HCO3- secretion by control and omeprazole-treated monolayers. The P2Y2 receptor agonist suppressed Mg2+ transport and stimulated apical HCO3- secretion through the Gq-protein coupled-phospholipase C (PLC) dependent pathway. Antagonists of cystic fibrosis transmembrane conductance regulator (CFTR) and Na+-HCO3- cotransporter-1 (NBCe1) could nullify the inhibitory effect of P2Y2 receptor agonist on Mg2+ transport across control and omeprazole-treated Caco-2 monolayers. Our results propose an inhibitory role of P2Y2 on intestinal Mg2+ absorption.

Characterization of UDP-Activated Purinergic Receptor P2Y6 Involved in Japanese Flounder Paralichthys olivaceus Innate Immunity

Uridine 5’-diphosphate (UDP)-activated purinergic receptor P2Y6 is a member of a G-protein-coupled purinergic receptor family that plays an important role in mammalian innate immunity. However, the role of the P2Y6 receptor (P2Y6R) in fish immunity has not been investigated. In this report, we characterized a P2Y6R gene from Japanese flounder (Paralichthys olivaceus) and examined its role in fish innate immunity. Sequence analysis reveals that the Japanese flounder P2Y6R protein is conserved and possesses four potential glycosylation sites. Quantitative real-time RT-PCR analysis shows that P2Y6R is broadly distributed in all examined Japanese flounder tissues with dominant expression in the liver. In addition, P2Y6R gene expression was up-regulated in head kidney macrophages (HKMs) upon lipopolysaccharides (LPS) and poly(I:C) stimulations but down-regulated by LPS challenge in peripheral blood leukocytes (PBLs). Furthermore, pharmacological inhibition of the endogenous P2Y6 receptor activity by the potently selective P2Y6R antagonist, MRS 2578, greatly up-regulated pro-inflammatory cytokine interleukin (IL)-1β, IL-6 and TNF-α gene expression in PBL cells treated with UDP. Moreover, LPS- and poly(I:C)-induced gene expression of IL-1β and TNF-α in Japanese flounder PBL cells was attenuated significantly by inhibition of P2Y6R activity with antagonist MRS 2578. Collectively, we, for the first time, showed the involvement of functional purinergic P2Y6R in fish innate immunity.

Proteomic analysis of canine oral tumor tissues using MALDI-TOF mass spectrometry and in-gel digestion coupled with mass spectrometry (GeLC MS/MS) approaches.

Oral tumors, including highly invasive and metastatic oral melanoma (OM), non-tonsillar oral squamous cell carcinoma (OSCC) and benign tumors (BN), are common neoplasms in dogs. Although these tumors behave differently, limited data of their protein expression profiles have been exhibited, particularly at the proteome level. The present study aimed to i.) characterize peptide-mass fingerprints (PMFs) and identify potential protein candidates of OM, OSCC, BN and normal control subjects, using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and liquid chromatography tandem mass spectrometry (LC-MS/MS), ii.) identify potential protein candidates associated with the diseases, using in-gel digestion coupled with mass spectrometric analysis (GeLC-MS/MS) and iii.) search for relationships between chemotherapy drugs and disease-perturbed proteins. A distinct cluster of each sample group and unique PMFs with identified protein candidates were revealed. The unique peptide fragment at 2,274 Da of sacsin molecular chaperone (SACS) was observed in early-stage OM whereas the fragment at 1,958 Da of sodium voltage-gated channel alpha subunit 10 (SCN10A) was presented in early- and late-stage OM. The peptide mass at 2,316 Da of Notch1 appeared in early-stage OM and benign oral tumors while the peptide mass at 2,505 Da of glutamate ionotropic receptor N-methyl-D-aspartate type subunit 3A (GRIN3A) was identified in all groups. Markedly expressed proteins from GeLC-MS/MS included Jumonji domain containing 1C (JMJD1C) in benign tumors, inversin (INVS) and rho guanine nucleotide exchange factor 28 (ARHGEF28) in OM, BTB domain-containing 16 (BTBD16) in OSCC, and protein tyrosine phosphatase non-receptor type 1 (PTPN1), BRCA2, DNA repair associated (BRCA2), WW domain binding protein 2 (WBP2), purinergic receptor P2Y1 and proteasome activator subunit 4 (PSME4) in all cancerous groups. The network connections between these proteins and chemotherapy drugs, cisplatin and doxorubicin, were also demonstrated. In conclusion, this study unveiled the unique PMFs and novel candidate protein markers of canine oral tumors.

Abstract 35: Triple-negative breast cancer cells alter the pulmonary landscape to favor metastasis via exosome-mediated release of NM23

Abstract There is strong evidence implicating exosomes, cell-derived nanoscale vesicles, and their protein cargo in facilitating dialogue between primary tumor cells and the premetastatic niche. Identified by our lab as one such protein, secreted nucleoside diphosphate kinase (NM23/NDPK) has been shown to activate endothelial remodeling in support of proangiogenic and prometastatic events. We have previously demonstrated that triple-negative breast cancer (MDA-MB-231) cells elaborate exosomes enriched with NDPK transphosphorylase activity and target the lung as a future site of metastasis. Using in vitro and in vivo approaches, we interrogate the functional role of NDPK in exosome-mediated lung remodeling. In cell-based assays, we demonstrate that MDA-MB-231 exosomes stimulate migration of pulmonary vascular endothelial cells and enhance monolayer permeability. These effects are reversed following treatment with an inhibitor of NDPK activity or an antagonist to the purinergic P2Y1 receptor. Further, we show that immune-compromised mice receiving intravenous injections of MDA-MB-231 exosomes exhibit enhanced pulmonary vascular leakage, whereas treatment with an inhibitor of NDPK attenuates this effect. Using tandem mass tag labeling and mass spectrometry, we profiled proteomic changes to the lung and identified the purinergic signaling pathway as among those significantly affected by exosome treatment. These results elucidate the functional role of exosomal NDPK in compromising vascular integrity and transforming the pulmonary landscape to support colonization by circulating breast cancer cells. Citation Format: Suzann Duan, Senny Nordmeier, Aidan E. Byrnes, Miles A. Brown, Iain L. Buxton. Triple-negative breast cancer cells alter the pulmonary landscape to favor metastasis via exosome-mediated release of NM23 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 35.

Use of Live Murine Pancreatic Slices for the Study of ß-Cell Regeneration

Introduction: Bone morphogenetic protein 7 (BMP-7), a protein with BMP-activating and TGF-β inactivating properties, induces the proliferation of a unique population of progenitor-like cells characterized by the expression of PDX1 and the BMP receptor activin-like kinase 3 (ALK3/BMPR1A). These cells can be sorted using ALK3 and the purinergic receptor P2Y1 (P2RY1) as a novel surrogate surface marker for PDX1. Sorted P2RY1+/ALK3bright+ cells form BMP-7 expandable colonies. Upon BMP-7 withdrawal, they differentiate into cells of all three lineages (endocrine, acinar and ductal) of the adult pancreas. PDX1+/ALK3+ cells absent from islets are represented in the major pancreatic ducts and pancreatic duct glands. Preliminary evidence indicates that these cells are also present in the murine pancreas. We hypothesized that islet β-cell regeneration could be studied in real time using live murine pancreatic slices transduced with a loxP-dsRed-loxP-EGFP reporter + insulin promoter-Cre adenovirus. If new β-cells arise from preexisting insulin-expressing-cells they would remain green. However, if neogenesis occurs from non-β-cells, there is a window of time during which the degrading red and the new green protein co-localize in the cell. Allowing us to discriminate between neogenesis and β-cell proliferation. Methods: Low melting point (LMP) agarose-embedded, vibratome-sectioned live pancreatic slices were generated from CD-1 mice. Transduction with a loxP-dsRed-loxP-EGFP reporter + insulin promoter-Cre adenovirus was done in slices cultured atop optically clear membranes. Slices were treated for 4 days with an ALK3 agonist (THR-123) or saline at the same time of the co-transduction. Bright field and fluorescence images of them were taken every 24h for 7 days. Conclusions: This is the first report on the use of live pancreatic slices as a novel tool for the study of pancreatic regeneration. Our preliminary results suggest that there are quantifiable β-cell neogenic events in response to BMP-7-like agents. Disclosure F. Qadir: None. J. Weitz: None. S. Alvarez-Cubela: None. D. Klein: None. G. Lanzoni: None. C.A. Garcia-Santana: Employee; Self; Ophysio Incorporated. A. Montalvo: None. C. Ricordi: None. L. Inverardi: None. A. Caicedo: None. R. Pastori: None. J. Domínguez-Bendala: Stock/Shareholder; Self; Ophysio.

Polymorphic Role of P2Y6 Receptor in Insulin Sensitive Organs—Adipose Tissue and Skeletal Muscle

Adipose tissue and skeletal muscle are the two largest insulin-sensitive organs in the body. They play a major role in maintaining whole body glucose and energy homeostasis. Insulin action results in glucose disposal principally in skeletal muscle and to a lesser extent in adipose tissue. Dysregulation of this function promotes the development of obesity, insulin resistance and type 2 diabetes. Many G protein-coupled receptors (GPCRs) are expressed in insulin sensitive organs and thus have emerged as potential targets for novel antidiabetic drugs. P2Y purinergic receptors are a class of GPCRs activated by nucleotides and nucleotide sugars. The purinergic P2Y6 receptor (P2Y6R) is activated by uridine 5’-diphosphate. The potential role of P2Y6R in adipose tissue and skeletal muscle with respect to maintaining whole body glucose homeostasis remains unexplored. To address this issue, we used Cre/loxP technology to generate mice that lack P2Y6R selectively in adipose tissue (AT-Y6-KO) or skeletal muscle (SK-Y6-KO). Interestingly, AT-Y6-KO mice consuming a high fat diet gained less weight, while SK-Y6-KO mice gained more weight than the corresponding control mice. Body composition revealed that the difference in body weight was due to loss or gain in fat mass in AT-Y6-KO and SK-Y6-KO mice, respectively. Improved vs. impaired glucose tolerance and insulin sensitivity was observed in AT-Y6-KO and SK-Y6-KO mice, respectively. Moreover, fasting blood glucose and fed plasma insulin levels were decreased in AT-Y6-KO mice. SK-Y6-KO mice showed elevated blood glucose and plasma insulin levels under both fasting and fed conditions. Detailed mechanistic studies are required for understanding the role of P2Y6R in metabolic tissues and to alter its function for therapeutic purposes. Disclosure S. Jain: None. J. Wess: None. K.A. Jacobson: None.