Tumoral P2Y receptor modulates tumor growth and host anti-tumor immune responses in a syngeneic murine model of oral cancer.

Head and neck squamous cell carcinomas (HNSCCs) are a heterogenous group of tumors and among the top 10 most common cancers and they arise from the epithelial tissues of the mucosal surfaces of the oral cavity, oropharynx, and larynx. Aberrant purinergic signaling has been associated with various cancer types. Here, we studied the role of the P2Y purinergic receptor (P2YR) in the context of oral cancer.

Early Dry Eye Disease Onset in a NOD.H-2h4 Mouse Model of Sjögren's Syndrome.

Purpose: To develop a mouse model of human dry eye disease (DED) for investigation of sex differences in autoimmune-associated dry eye pathology.

Methods: Ocular surface disease was assessed by quantifying corneal epithelial damage with lissamine green stain in the NOD.H-2h4,IFNγ-/-,CD28-/- (NOD.

Indomethacin Treatment Post-irradiation Improves Mouse Parotid Salivary Gland Function via Modulation of Prostaglandin E Signaling.

Annually, >600,000 new cases of head and neck cancer (HNC) are diagnosed worldwide with primary treatment being surgery and radiotherapy. During ionizing radiation (IR) treatment of HNC, healthy salivary glands are collaterally damaged, leading to loss of function that severely diminishes the quality of life for patients due to increased health complications, including oral infections and sores, cavities, and malnutrition, among others. Therapies for salivary hypofunction are ineffective and largely palliative, indicating a need for further research to uncover effective approaches to prevent or restore loss of salivary gland function following radiotherapy.

P2Y receptor antagonism resolves sialadenitis and improves salivary flow in a Sjögren's syndrome mouse model.

Objective: Sjögren's syndrome (SS) is a chronic autoimmune exocrinopathy characterized by lymphocytic infiltration of the salivary and lacrimal glands and decreased saliva and tear production. Previous studies indicate that the G protein-coupled P2Y nucleotide receptor (P2YR) is upregulated in numerous models of salivary gland inflammation (i.e.

P2Y receptors for extracellular nucleotides: Contributions to cancer progression and therapeutic implications.

Purinergic receptors for extracellular nucleotides and nucleosides contribute to a vast array of cellular and tissue functions, including cell proliferation, intracellular and transmembrane ion flux, immunomodulation and thrombosis. In mammals, the purinergic receptor system is composed of G protein-coupled P1 receptors A, A, A and A for extracellular adenosine, P2X1-7 receptors that are ATP-gated ion channels and G protein-coupled P2Y receptors for extracellular ATP, ADP, UTP, UDP and/or UDP-glucose. Recent studies have implicated specific P2Y receptor subtypes in numerous oncogenic processes, including cancer tumorigenesis, metastasis and chemotherapeutic drug resistance, where G protein-mediated signaling cascades modulate intracellular ion concentrations and activate downstream protein kinases, Src family kinases as well as numerous mitogen-activated protein kinases.

Cell Sheets Restore Secretory Function in Wounded Mouse Submandibular Glands.

Thermoresponsive cell culture plates release cells as confluent living sheets in response to small changes in temperature, with recovered cell sheets retaining functional extracellular matrix proteins and tight junctions, both of which indicate formation of intact and functional tissue. Our recent studies demonstrated that cell sheets are highly effective in promoting mouse submandibular gland (SMG) cell differentiation and recovering tissue integrity. However, these studies were performed only at early time points and extension of the observation period is needed to investigate duration of the cell sheets.

P2Y receptors mediate nucleotide-induced EGFR phosphorylation and stimulate proliferation and tumorigenesis of head and neck squamous cell carcinoma cell lines.

Objectives: To assess functional expression of the P2Y nucleotide receptor (P2YR) in head and neck squamous cell carcinoma (HNSCC) cell lines and define its role in nucleotide-induced epidermal growth factor receptor (EGFR) transactivation. The use of anti-EGFR therapeutics to treat HNSCC is hindered by intrinsic and acquired drug resistance. Defining novel pathways that modulate EGFR signaling could identify additional targets to treat HNSCC.

P2 Receptors as Therapeutic Targets in the Salivary Gland: From Physiology to Dysfunction.

Although often overlooked in our daily lives, saliva performs a host of necessary physiological functions, including lubricating and protecting the oral cavity, facilitating taste sensation and digestion and maintaining tooth enamel. Therefore, salivary gland dysfunction and hyposalivation, often resulting from pathogenesis of the autoimmune disease Sjögren's syndrome or from radiotherapy of the head and neck region during cancer treatment, severely reduce the quality of life of afflicted patients and can lead to dental caries, periodontitis, digestive disorders, loss of taste and difficulty speaking. Since their initial discovery in the 1970s, P2 purinergic receptors for extracellular nucleotides, including ATP-gated ion channel P2X and G protein-coupled P2Y receptors, have been shown to mediate physiological processes in numerous tissues, including the salivary glands where P2 receptors represent a link between canonical and non-canonical saliva secretion.

P2X7 receptor deletion suppresses γ-radiation-induced hyposalivation.

Head and neck cancer treatments typically involve a combination of surgery and radiotherapy, often leading to collateral damage to nearby tissues causing unwanted side effects. Radiation damage to salivary glands frequently leads to irreversible dysfunction by poorly understood mechanisms. The P2X7 receptor (P2X7R) is a ligand-gated ion channel activated by extracellular ATP released from damaged cells as "danger signals.

P2X7 receptor antagonism prevents IL-1β release from salivary epithelial cells and reduces inflammation in a mouse model of autoimmune exocrinopathy.

Salivary gland inflammation is a hallmark of Sjögren's syndrome (SS), a common autoimmune disease characterized by lymphocytic infiltration of the salivary gland and loss of saliva secretion, predominantly in women. The P2X7 receptor (P2X7R) is an ATP-gated nonselective cation channel that induces inflammatory responses in cells and tissues, including salivary gland epithelium. In immune cells, P2X7R activation induces the production of proinflammatory cytokines, including IL-1β and IL-18, by inducing the oligomerization of the multiprotein complex NLRP3-type inflammasome.

New Murine Model of Early Onset Autoimmune Thyroid Disease/Hypothyroidism and Autoimmune Exocrinopathy of the Salivary Gland.

Sixty to seventy percent of IFN-γ(-/-) NOD.H-2h4 mice given sodium iodide (NaI)-supplemented water develop a slow onset autoimmune thyroid disease, characterized by thyrocyte epithelial cell (TEC) hyperplasia and proliferation (H/P). TEC H/P develops much earlier in CD28(-/-) mice and nearly 100% (both sexes) have severe TEC H/P at 4 mo of age.

Purinergic receptors as potential therapeutic targets in Alzheimer's disease.

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by a progressive loss of memory and cognitive ability and is a serious cause of mortality. Many of the pathological characteristics associated with AD are revealed post-mortem, including amyloid-β plaque deposition, neurofibrillary tangles containing hyperphosphorylated tau proteins and neuronal loss in the hippocampus and cortex. Although several genetic mutations and risk factors have been associated with the disease, the causes remain poorly understood.

Increased Expression of TGF-β Signaling Components in a Mouse Model of Fibrosis Induced by Submandibular Gland Duct Ligation.

Transforming growth factor-β (TGF-β) is a multi-functional cytokine with a well-described role in the regulation of tissue fibrosis and regeneration in the liver, kidney and lung. Submandibular gland (SMG) duct ligation and subsequent deligation in rodents is a classical model for studying salivary gland damage and regeneration. While previous studies suggest that TGF-β may contribute to salivary gland fibrosis, the expression of TGF-β signaling components has not been investigated in relation to mouse SMG duct ligation-induced fibrosis and regeneration following ductal deligation.

Highly potent and selective ectonucleotide pyrophosphatase/phosphodiesterase I inhibitors based on an adenosine 5'-(α or γ)-thio-(α,β- or β,γ)-methylenetriphosphate scaffold.

Aberrant nucleotide pyrophosphatase/phosphodiesterase-1 (NPP1) activity is associated with chondrocalcinosis, osteoarthritis, and type 2 diabetes. The potential of NPP1 inhibitors as therapeutic agents, and the scarceness of their structure-activity relationship, encouraged us to develop new NPP1 inhibitors. Specifically, we synthesized ATP-α-thio-β,γ-CH2 (1), ATP-α-thio-β,γ-CCl2 (2), ATP-α-CH2-γ-thio (3), and 8-SH-ATP (4) and established their resistance to hydrolysis by NPP1,3 and NTPDase1,2,3,8 (<5% hydrolysis) (NTPDase = ectonucleoside triphosphate diphosphohydrolase).

P2Y2 nucleotide receptor activation enhances the aggregation and self-organization of dispersed salivary epithelial cells.

Hyposalivation resulting from salivary gland dysfunction leads to poor oral health and greatly reduces the quality of life of patients. Current treatments for hyposalivation are limited. However, regenerative medicine to replace dysfunctional salivary glands represents a revolutionary approach.

Loss of P2Y₂ nucleotide receptors enhances early pathology in the TgCRND8 mouse model of Alzheimer's disease.

Neuroinflammation is a prominent feature in Alzheimer's disease (AD) and activation of the brain's innate immune system, particularly microglia, has been postulated to both retard and accelerate AD progression. Recent studies indicate that the G protein-coupled P2Y2 nucleotide receptor (P2Y2R) is an important regulator of innate immunity by assisting in the recruitment of monocytes to injured tissue, neutrophils to bacterial infections and eosinophils to allergen-infected lungs. In this study, we investigated the role of the P2Y2R in progression of an AD-like phenotype in the TgCRND8 mouse model that expresses Swedish and Indiana mutations in amyloid precursor protein (APP).

Up-regulation and activation of the P2Y(2) nucleotide receptor mediate neurite extension in IL-1β-treated mouse primary cortical neurons.

The pro-inflammatory cytokine interleukin-1β (IL-1β), whose levels are elevated in the brain in Alzheimer's and other neurodegenerative diseases, has been shown to have both detrimental and beneficial effects on disease progression. In this article, we demonstrate that incubation of mouse primary cortical neurons (mPCNs) with IL-1β increases the expression of the P2Y2 nucleotide receptor (P2Y2R) and that activation of the up-regulated receptor with UTP, a relatively selective agonist of the P2Y2R, increases neurite outgrowth. Consistent with the accepted role of cofilin in the regulation of neurite extension, results indicate that incubation of IL-1β-treated mPCNs with UTP increases the phosphorylation of cofilin, a response absent in PCNs isolated from P2Y2R(-/-) mice.

P2X7 receptor activation induces inflammatory responses in salivary gland epithelium.

Inflammation of the salivary gland is a well-documented aspect of salivary gland dysfunction that occurs in Sjogren's syndrome (SS), an autoimmune disease, and in γ-radiation-induced injury during treatment of head and neck cancers. Extracellular nucleotides have gained recognition as key modulators of inflammation through activation of cell surface ionotropic and metabotropic receptors, although the contribution of extracellular nucleotides to salivary gland inflammation is not well understood. In vitro studies using submandibular gland (SMG) cell aggregates isolated from wild-type C57BL/6 mice indicate that treatment with ATP or the high affinity P2X7R agonist 3'-O-(4-benzoyl)benzoyl-ATP (BzATP) induces membrane blebbing and enhances caspase activity, responses that were absent in SMG cell aggregates isolated from mice lacking the P2X7R (P2X7R(-/-)).

Identification of a promising drug candidate for the treatment of type 2 diabetes based on a P2Y(1) receptor agonist.

The activation by extracellular nucleotides of pancreatic P2Y receptors, particularly, the P2Y(1)R subtype, increases insulin secretion. Therefore, we developed analogues of the P2Y(1)R receptor agonist 2-MeS-ADP, as potential antidiabetic drugs. Analogue 3A was found to be a potent P2Y(1)R agonist (EC(50) = 0.

Neuroprotective roles of the P2Y(2) receptor.

Purinergic signaling plays a unique role in the brain by integrating neuronal and glial cellular circuits. The metabotropic P1 adenosine receptors and P2Y nucleotide receptors and ionotropic P2X receptors control numerous physiological functions of neuronal and glial cells and have been implicated in a wide variety of neuropathologies. Emerging research suggests that purinergic receptor interactions between cells of the central nervous system (CNS) have relevance in the prevention and attenuation of neurodegenerative diseases resulting from chronic inflammation.

P2 receptors for extracellular nucleotides in the central nervous system: role of P2X7 and P2Y₂ receptor interactions in neuroinflammation.

Extracellular nucleotides induce cellular responses in the central nervous system (CNS) through the activation of ionotropic P2X and metabotropic P2Y nucleotide receptors. Activation of these receptors regulates a wide range of physiological and pathological processes. In this review, we present an overview of the current literature regarding P2X and P2Y receptors in the CNS with a focus on the contribution of P2X7 and P2Y(2) receptor-mediated responses to neuroinflammatory and neuroprotective mechanisms.

Nucleotides released from Aβ₁₋₄₂ -treated microglial cells increase cell migration and Aβ₁₋₄₂ uptake through P2Y₂ receptor activation.

Amyloid β-protein (Aβ) deposits in brains of Alzheimer's disease patients generate proinflammatory cytokines and chemokines that recruit microglial cells to phagocytose Aβ. Nucleotides released from apoptotic cells activate P2Y(2) receptors (P2Y(2) Rs) in macrophages to promote clearance of dead cells. In this study, we investigated the role of P2Y(2) Rs in the phagocytosis and clearance of Aβ.

Boranophosphate isoster controls P2Y-receptor subtype selectivity and metabolic stability of dinucleoside polyphosphate analogues.

Dinucleoside polyphosphates, Np(n)N', exert their physiological effects via P2 receptors (P2Rs). Np(n)N' are attractive drug candidates as they offer better stability and specificity compared to nucleotides, the most common P2R ligands. To further improve the agonist properties of Np(n)N', we synthesized novel isosters of dinucleoside polyphosphates where N and N' are A or U and where the Pα or Pβ phosphate groups are replaced by boranophosphate, denoted as Np(n)(α-B)N' or Np(n)(β-B)N' (n = 3, 4), respectively.

P2Y2 nucleotide receptor-mediated responses in brain cells.

Acute inflammation is important for tissue repair; however, chronic inflammation contributes to neurodegeneration in Alzheimer's disease (AD) and occurs when glial cells undergo prolonged activation. In the brain, stress or damage causes the release of nucleotides and activation of the G(q) protein-coupled P2Y(2) nucleotide receptor subtype (P2Y(2)R) leading to pro-inflammatory responses that can protect neurons from injury, including the stimulation and recruitment of glial cells. P2Y(2)R activation induces the phosphorylation of the epidermal growth factor receptor (EGFR), a response dependent upon the presence of a SH3 binding domain in the intracellular C terminus of the P2Y(2)R that promotes Src binding and transactivation of EGFR, a pathway that regulates the proliferation of cortical astrocytes.

2-MeS-beta,gamma-CCl2-ATP is a potent agent for reducing intraocular pressure.

Extracellular nucleotides can modify the production or drainage of the aqueous humor via activation of P2 receptors and therefore affect the intraocular pressure (IOP). We have synthesized slowly hydrolyzable nucleoside di- and triphosphate analogues, 1, and 8-14. Analogues 8-14 were completely resistant to hydrolysis by alkaline phosphatase over 30 min at 37 degrees C.