WorldWideScience

Sample records for a2 receptor targeting

  1. Ephrin A2 receptor targeting does not increase adenoviral pancreatic cancer transduction in vivo

    NARCIS (Netherlands)

    van Geer, M.A.; Bakker, C.T.; Koizumi, N.; Mizuguchi, H.; Wesseling, J.G.; Oude Elferink, R.P.J.; Bosma, P.J.

    2009-01-01

    AIM: To generate an adenoviral vector specifically targeting the EphA2 receptor (EphA2R) highly expressed on pancreatic cancer cells in vivo. METHODS: YSA, a small peptide ligand that binds the EphA2R with high affinity, was inserted into the HI loop of the adenovirus serotype 5 fiber knob. To furth

  2. Ephrin A2 receptor targeting does not increase adenoviral pancreatic cancer transduction in vivo

    Institute of Scientific and Technical Information of China (English)

    Michael A van Geer; Conny T Bakker; Naoya Koizumi; Hiroyuki Mizuguchi; John G Wesseling; Ronald PJ Oude Elferink; Piter J Bosma

    2009-01-01

    AIM:To generate an adenoviral vector specifically targeting the EphA2 receptor (EphA2R) highly expressed on pancreatic cancer cells in vivo.METHODS:YSA,a small peptide ligand that binds the EphA2R with high affinity,was inserted into the HI loop of the adenovirus serotype 5 fiber knob.To further increase the specificity of this vector,binding sites for native adenoviral receptors,the coxsackie and adenovirus receptor (CAR) and integrin,were ablated from the viral capsid.The ablated retargeted adenoviral vector was produced on 293T cells.Specific targeting of this novel adenoviral vector to pancreatic cancer was investigated on established human pancreatic cancer cell lines.Upon demonstrating specific in vitro targeting,in vivo targeting to subcutaneous growing human pancreatic cancer was tested by intravenous and intraperitoneal administration of the ablated adenoviral vector.RESULTS:Ablation of native cellular binding sites reduced adenoviral transduction at least 100-fold.Insertion of the YSA peptide in the HI loop restored adenoviral transduction of EphA2R-expressing cells but not of cells lacking this receptor.YSA-mediated transduction was inhibited by addition of synthetic YSA peptide.The transduction specificity of the ablated retargeted vector towards human pancreatic cancer cells was enhanced almost 10-fold in vitro.In a subsequent in vivo study in a nude (nu/nu) mouse model however,no increased adenoviral targeting to subcutaneously growing human pancreas cancer nodules was seen upon injection into the tail vein,nor upon injection into the peritoneum.CONCLUSION:Targeting the EphA2 receptor increases specificity of adenoviral transduction of human pancreatic cancer cells in vitro but fails to enhance pancreatic cancer transduction in vivo.

  3. M-Type Phospholipase A2 Receptor as Target Antigen in Idiopathic Membranous Nephropathy

    Science.gov (United States)

    Beck, Laurence H.; Bonegio, Ramon G.B.; Lambeau, Gérard; Beck, David M.; Powell, David W.; Cummins, Timothy D.; Klein, Jon B.; Salant, David J.

    2009-01-01

    BACKGROUND Idiopathic membranous nephropathy, a common form of the nephrotic syndrome, is an antibody-mediated autoimmune glomerular disease. Serologic diagnosis has been elusive because the target antigen is unknown. METHODS We performed Western blotting of protein extracts from normal human glomeruli with serum samples from patients with idiopathic or secondary membranous nephropathy or other proteinuric or autoimmune diseases and from normal controls. We used mass spectrometry to analyze the reactive protein bands and confirmed the identity and location of the target antigen with a monospecific antibody. RESULTS Serum samples from 26 of 37 patients (70%) with idiopathic but not secondary membranous nephropathy specifically identified a 185-kD glycoprotein in non-reduced glomerular extract. Mass spectrometry of the reactive protein band detected the M-type phospholipase A2 receptor (PLA2R). Reactive serum specimens recognized recombinant PLA2R and bound the same 185-kD glomerular protein as did the monospecific anti-PLA2R antibody. Anti-PLA2R autoantibodies in serum samples from patients with membranous nephropathy were mainly IgG4, the predominant immunoglobulin subclass in glomerular deposits. PLA2R was expressed in podocytes in normal human glomeruli and colocalized with IgG4 in immune deposits in glomeruli of patients with membranous nephropathy. IgG eluted from such deposits in patients with idiopathic membranous nephropathy, but not in those with lupus membranous or IgA nephropathy, recognized PLA2R. CONCLUSIONS A majority of patients with idiopathic membranous nephropathy have antibodies against a conformation-dependent epitope in PLA2R. PLA2R is present in normal podocytes and in immune deposits in patients with idiopathic membranous nephropathy, indicating that PLA2R is a major antigen in this disease. PMID:19571279

  4. Targeting Adenosine A2A Receptors in Parkinson’s Disease

    Science.gov (United States)

    2006-11-01

    University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, Piscataway, NJ USA Background: The blockade of A2A receptors...IRP/NIH/DHHS Baltimore MD Gilberto Fisone Karolinska Institutet Stockholm Sweden Laura Font University of Connecticut Storrs CT Yolanda Fortin

  5. Phosphotyrosine profiling identifies ephrin receptor A2 as a potential therapeutic target in esophageal squamous-cell carcinoma.

    Science.gov (United States)

    Syed, Nazia; Barbhuiya, Mustafa A; Pinto, Sneha M; Nirujogi, Raja Sekhar; Renuse, Santosh; Datta, Keshava K; Khan, Aafaque Ahmad; Srikumar, Kotteazeth; Prasad, T S Keshava; Kumar, M Vijaya; Kumar, Rekha Vijay; Chatterjee, Aditi; Pandey, Akhilesh; Gowda, Harsha

    2015-01-01

    Esophageal squamous-cell carcinoma (ESCC) is one of the most common malignancies in Asia. Currently, surgical resection of early-stage tumor is the best available treatment. However, most patients present late when surgery is not an option. Data suggest that chemotherapy regimens are inadequate for clinical management of advanced cancer. Targeted therapy has emerged as one of the most promising approaches to treat several malignancies. A prerequisite for developing targeted therapy is prior knowledge of proteins and pathways that drive proliferation in malignancies. We carried out phosphotyrosine profiling across four different ESCC cell lines and compared it to non-neoplastic Het-1A cell line to identify activated tyrosine kinase signaling pathways in ESCC. A total of 278 unique phosphopeptides were identified across these cell lines. This included several tyrosine kinases and their substrates that were hyperphosphorylated in ESCC. Ephrin receptor A2 (EPHA2), a receptor tyrosine kinase, was hyperphosphorylated in all the ESCC cell lines used in the study. EPHA2 is reported to be oncogenic in several cancers and is also known to promote metastasis. Immunohistochemistry-based studies have revealed EPHA2 is overexpressed in nearly 50% of ESCC. We demonstrated EPHA2 as a potential therapeutic target in ESCC by carrying out siRNA-based knockdown studies. Knockdown of EPHA2 in ESCC cell line TE8 resulted in significant decrease in cell proliferation and invasion, suggesting it is a promising therapeutic target in ESCC that warrants further evaluation.

  6. Drug-target residence time : a case for the adenosine A1 and A2A receptors

    NARCIS (Netherlands)

    Guo, Dong

    2014-01-01

    Ligand-receptor binding kinetics is increasingly recognized to play a pivotal role in the early phase of drug design and discovery. In this thesis ligand-receptor binding kinetics, particularly residence time, at the adenosine A1 and A2A receptors was extensively investigated. Several case studies

  7. The caffeine-binding adenosine A2A receptor induces age-like HPA-axis dysfunction by targeting glucocorticoid receptor function.

    Science.gov (United States)

    Batalha, Vânia L; Ferreira, Diana G; Coelho, Joana E; Valadas, Jorge S; Gomes, Rui; Temido-Ferreira, Mariana; Shmidt, Tatiana; Baqi, Younis; Buée, Luc; Müller, Christa E; Hamdane, Malika; Outeiro, Tiago F; Bader, Michael; Meijsing, Sebastiaan H; Sadri-Vakili, Ghazaleh; Blum, David; Lopes, Luísa V

    2016-08-11

    Caffeine is associated with procognitive effects in humans by counteracting overactivation of the adenosine A2A receptor (A2AR), which is upregulated in the human forebrain of aged and Alzheimer's disease (AD) patients. We have previously shown that an anti-A2AR therapy reverts age-like memory deficits, by reestablishment of the hypothalamic-pituitary-adrenal (HPA) axis feedback and corticosterone circadian levels. These observations suggest that A2AR over-activation and glucocorticoid dysfunction are key events in age-related hippocampal deficits; but their direct connection has never been explored. We now show that inducing A2AR overexpression in an aging-like profile is sufficient to trigger HPA-axis dysfunction, namely loss of plasmatic corticosterone circadian oscillation, and promotes reduction of GR hippocampal levels. The synaptic plasticity and memory deficits triggered by GR in the hippocampus are amplified by A2AR over-activation and were rescued by anti-A2AR therapy; finally, we demonstrate that A2AR act on GR nuclear translocation and GR-dependent transcriptional regulation. We provide the first demonstration that A2AR is a major regulator of GR function and that this functional interconnection may be a trigger to age-related memory deficits. This supports the idea that the procognitive effects of A2AR antagonists, namely caffeine, on Alzheimer's and age-related cognitive impairments may rely on its ability to modulate GR actions.

  8. The caffeine-binding adenosine A2A receptor induces age-like HPA-axis dysfunction by targeting glucocorticoid receptor function

    Science.gov (United States)

    Batalha, Vânia L.; Ferreira, Diana G.; Coelho, Joana E.; Valadas, Jorge S.; Gomes, Rui; Temido-Ferreira, Mariana; Shmidt, Tatiana; Baqi, Younis; Buée, Luc; Müller, Christa E.; Hamdane, Malika; Outeiro, Tiago F.; Bader, Michael; Meijsing, Sebastiaan H.; Sadri-Vakili, Ghazaleh; Blum, David; Lopes, Luísa V.

    2016-01-01

    Caffeine is associated with procognitive effects in humans by counteracting overactivation of the adenosine A2A receptor (A2AR), which is upregulated in the human forebrain of aged and Alzheimer’s disease (AD) patients. We have previously shown that an anti-A2AR therapy reverts age-like memory deficits, by reestablishment of the hypothalamic-pituitary-adrenal (HPA) axis feedback and corticosterone circadian levels. These observations suggest that A2AR over-activation and glucocorticoid dysfunction are key events in age-related hippocampal deficits; but their direct connection has never been explored. We now show that inducing A2AR overexpression in an aging-like profile is sufficient to trigger HPA-axis dysfunction, namely loss of plasmatic corticosterone circadian oscillation, and promotes reduction of GR hippocampal levels. The synaptic plasticity and memory deficits triggered by GR in the hippocampus are amplified by A2AR over-activation and were rescued by anti-A2AR therapy; finally, we demonstrate that A2AR act on GR nuclear translocation and GR-dependent transcriptional regulation. We provide the first demonstration that A2AR is a major regulator of GR function and that this functional interconnection may be a trigger to age-related memory deficits. This supports the idea that the procognitive effects of A2AR antagonists, namely caffeine, on Alzheimer’s and age-related cognitive impairments may rely on its ability to modulate GR actions. PMID:27510168

  9. Synthesis and pharmacological evaluation of dual acting ligands targeting the adenosine A2A and dopamine D2 receptors for the potential treatment of Parkinson's disease.

    Science.gov (United States)

    Jörg, Manuela; May, Lauren T; Mak, Frankie S; Lee, Kiew Ching K; Miller, Neil D; Scammells, Peter J; Capuano, Ben

    2015-01-22

    A relatively new strategy in drug discovery is the development of dual acting ligands. These molecules are potentially able to interact at two orthosteric binding sites of a heterodimer simultaneously, possibly resulting in enhanced subtype selectivity, higher affinity, enhanced or modified physiological response, and reduced reliance on multiple drug administration regimens. In this study, we have successfully synthesized a series of classical heterobivalent ligands as well as a series of more integrated and "drug-like" dual acting molecules, incorporating ropinirole as a dopamine D2 receptor agonist and ZM 241385 as an adenosine A2A receptor antagonist. The best compounds of our series maintained the potency of the original pharmacophores at both receptors (adenosine A2A and dopamine D2). In addition, the integrated dual acting ligands also showed promising results in preliminary blood-brain barrier permeability tests, whereas the classical heterobivalent ligands are potentially more suited as pharmacological tools.

  10. Local and systemic tolerability of a 2'O-methoxyethyl antisense oligonucleotide targeting interleukin-4 receptor-α delivery by inhalation in mouse and monkey.

    Science.gov (United States)

    Fey, Robert A; Templin, Michael V; McDonald, Jacob D; Yu, Rosie Z; Hutt, Julie A; Gigliotti, Andrew P; Henry, Scott P; Reed, Matthew D

    2014-07-01

    Antisense oligonucleotides (ASOs) bind and facilitate degradation of RNA and inhibit protein expression in pathways not easily targeted with small molecules or antibodies. Interleukin (IL)-4 and IL-13 potentiate signaling through the shared IL-4 receptor-α (IL-4Rα) subunit of their receptors. ASO targeting of IL-4Rα mRNA in a mouse model of asthma led to attenuation of airway hyperactivity, demonstrating potential benefit in asthma patients. This study focused on tolerability of inhaled IL-4Rα-targeting ASOs. Toxicity studies were performed with mouse- (ISIS 23189) and human-specific (ISIS 369645) sequences administered by inhalation. Four week (monkey) or 13 week (mouse) repeat doses at levels of up to 15 mg/kg/exposure (exp) and 50 mg/kg/exp, respectively, demonstrated dose-dependent effects limited to increases in macrophage size and number in lung and tracheobronchial lymph nodes. The changes were largely non-specific, reflecting adaptive responses that occur during active exposure and deposition of ASO and other material in the lung. Reversibility was observed at a rate consistent with the kinetics of tissue clearance of ASO. Systemic bioavailability was minimal, and no systemic toxicity was observed at exposure levels appreciably above pharmacological doses and doses proposed for clinical trials.

  11. Mannose receptor-targeted vaccines.

    Science.gov (United States)

    Keler, Tibor; Ramakrishna, Venky; Fanger, Michael W

    2004-12-01

    Targeting antigens to endocytic receptors on professional antigen-presenting cells (APCs) represents an attractive strategy to enhance the efficacy of vaccines. Such APC-targeted vaccines have an exceptional ability to guide exogenous protein antigens into vesicles that efficiently process the antigen for major histocompatibility complex class I and class II presentation. Efficient targeting not only requires high specificity for the receptor that is abundantly expressed on the surface of APCs, but also the ability to be rapidly internalised and loaded into compartments that contain elements of the antigen-processing machinery. The mannose receptor (MR) and related C-type lectin receptors are particularly designed to sample antigens (self and non-self), much like pattern recognition receptors, to integrate the innate with adaptive immune responses. In fact, a variety of approaches involving delivery of antigens to the MR have demonstrated effective induction of potent cellular and humoral immune responses. Yet, although several lines of evidence in diverse experimental systems attest to the efficacy of targeted vaccine strategies, it is becoming increasingly clear that additional signals, such as those afforded by adjuvants, may be critical to elicit sustained immunity. Therefore, MR-targeted vaccines are likely to be most efficacious in vivo when combined with agents that elicit complementary activation signals. Certainly, a better understanding of the mechanism associated with the induction of immune responses as a result of targeting antigens to the MR, will be important in exploiting MR-targeted vaccines not only for mounting immune defenses against cancer and infectious disease, but also for specific induction of tolerance in the treatment of autoimmune disease.

  12. Adenosine receptor targeting in health and disease.

    Science.gov (United States)

    Gessi, Stefania; Merighi, Stefania; Fazzi, Debora; Stefanelli, Angela; Varani, Katia; Borea, Pier Andrea

    2011-12-01

    The adenosine receptors A(1), A(2A), A(2B) and A(3) are important and ubiquitous mediators of cellular signaling that play vital roles in protecting tissues and organs from damage. In particular, adenosine triggers tissue protection and repair by different receptor-mediated mechanisms, including increasing the oxygen supply:demand ratio, pre-conditioning, anti-inflammatory effects and the stimulation of angiogenesis. The state of the art of the role of adenosine receptors which have been proposed as targets for drug design and discovery, in health and disease, and an overview of the ligands for these receptors in clinical development. Selective ligands of A(1), A(2A), A(2B) and A(3) adenosine receptors are likely to find applications in the treatment of pain, ischemic conditions, glaucoma, asthma, arthritis, cancer and other disorders in which inflammation is a feature. The aim of this review is to provide an overview of the present knowledge regarding the role of these adenosine receptors in health and disease.

  13. Receptor-targeted metalloradiopharmaceuticals. Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    Green, Mark A.

    2000-03-22

    Copper (II) and platinum (II) coordination complexes were prepared and characterized. These complexes were designed to afford structural homology with steroidal and non-steroidal estrogens for possible use as receptor-targeted radiopharmaceuticals. While weak affinity for the estrogen receptor was detectable, none would appear to have sufficient receptor-affinity for estrogen-receptor-targeted imaging or therapy.

  14. Role of adenosine A2b receptor overexpression in tumor progression.

    Science.gov (United States)

    Sepúlveda, Cesar; Palomo, Iván; Fuentes, Eduardo

    2016-12-01

    The adenosine A2b receptor is a G-protein coupled receptor. Its activation occurs with high extracellular adenosine concentration, for example in inflammation or hypoxia. These conditions are generated in the tumor environment. Studies show that A2b receptor is overexpressed in various tumor lines and biopsies from patients with different cancers. This suggests that A2b receptor can be used by tumor cells to promote progression. Thus A2b participates in different events, such as angiogenesis and metastasis, besides exerting immunomodulatory effects that protect tumor cells. Therefore, adenosine A2b receptor appears as an interesting therapeutic target for cancer treatment.

  15. Adenosine A2A Receptors and A2A Receptor Heteromers as Key Players in Striatal Function

    Science.gov (United States)

    Ferré, Sergi; Quiroz, César; Orru, Marco; Guitart, Xavier; Navarro, Gemma; Cortés, Antonio; Casadó, Vicent; Canela, Enric I.; Lluis, Carme; Franco, Rafael

    2011-01-01

    A very significant density of adenosine A2A receptors (A2ARs) is present in the striatum, where they are preferentially localized postsynaptically in striatopallidal medium spiny neurons (MSNs). In this localization A2ARs establish reciprocal antagonistic interactions with dopamine D2 receptors (D2Rs). In one type of interaction, A2AR and D2R are forming heteromers and, by means of an allosteric interaction, A2AR counteracts D2R-mediated inhibitory modulation of the effects of NMDA receptor stimulation in the striatopallidal neuron. This interaction is probably mostly responsible for the locomotor depressant and activating effects of A2AR agonist and antagonists, respectively. The second type of interaction involves A2AR and D2R that do not form heteromers and takes place at the level of adenylyl cyclase (AC). Due to a strong tonic effect of endogenous dopamine on striatal D2R, this interaction keeps A2AR from signaling through AC. However, under conditions of dopamine depletion or with blockade of D2R, A2AR-mediated AC activation is unleashed with an increased gene expression and activity of the striatopallidal neuron and with a consequent motor depression. This interaction is probably the main mechanism responsible for the locomotor depression induced by D2R antagonists. Finally, striatal A2ARs are also localized presynaptically, in cortico-striatal glutamatergic terminals that contact the striato-nigral MSN. These presynaptic A2ARs heteromerize with A1 receptors (A1Rs) and their activation facilitates glutamate release. These three different types of A2ARs can be pharmacologically dissected by their ability to bind ligands with different affinity and can therefore provide selective targets for drug development in different basal ganglia disorders. PMID:21731559

  16. Adenosine A2A receptors and A2A receptor heteromers as key players in striatal function

    Directory of Open Access Journals (Sweden)

    Sergi eFerre

    2011-06-01

    Full Text Available A very significant density of adenosine adenosine A2A receptors (A2ARs is present in the striatum, where they are preferentially localized postsynaptically in striatopallidal medium spiny neurons (MSNs. In this localization A2ARs establish reciprocal antagonistic interactions with dopamine D2 receptors (D2Rs. In one type of interaction, A2AR and D2R are forming heteromers and, by means of an allosteric interaction, A2AR counteracts D2R-mediated inhibitory modulation of the effects of NMDA receptor stimulation in the striato-pallidal neuron. This interaction is probably mostly responsible for the locomotor depressant and activating effects of A2AR agonist and antagonists, respectively. The second type of interaction involves A2AR and D2R that do not form heteromers and takes place at the level of adenylyl-cyclase (AC. Due to a strong tonic effect of endogenous dopamine on striatal D2R, this interaction keeps A2AR from signaling through AC. However, under conditions of dopamine depletion or with blockade of D2R, A2AR-mediated AC activation is unleashed with an increased gene expression and activity of the striato-pallidal neuron and with a consequent motor depression. This interaction is probably the main mechanism responsible for the locomotor depression induced by D2R antagonists. Finally, striatal A2ARs are also localized presynaptically, in cortico-striatal glutamatergic terminals that contact the striato-nigral MSN. These presynaptic A2ARs heteromerize with A1 receptors (A1Rs and their activation facilitates glutamate release. These three different types of A2ARs can be pharmacologically dissected by their ability to bind ligands with different affinity and can therefore provide selective targets for drug development in different basal ganglia disorders.

  17. Targeting Discoidin Domain Receptors in Prostate Cancer

    Science.gov (United States)

    2016-08-01

    1 AWARD NUMBER: W81XWH-15-1-0226 TITLE: Targeting Discoidin Domain Receptors in Prostate Cancer PRINCIPAL INVESTIGATOR: Dr. Rafael Fridman...4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER W81XWH-15-1-0226 Targeting Discoidin Domain Receptors in Prostate Cancer 5b. GRANT NUMBER W81XWH-15...DDRs in prostate cancer . During the first funding period, we conducted immunohistochemical studies by staining a 200 case Grade/Stage tissue

  18. Targeting Nuclear Receptors with Marine Natural Products

    Directory of Open Access Journals (Sweden)

    Chunyan Yang

    2014-01-01

    Full Text Available Nuclear receptors (NRs are important pharmaceutical targets because they are key regulators of many metabolic and inflammatory diseases, including diabetes, dyslipidemia, cirrhosis, and fibrosis. As ligands play a pivotal role in modulating nuclear receptor activity, the discovery of novel ligands for nuclear receptors represents an interesting and promising therapeutic approach. The search for novel NR agonists and antagonists with enhanced selectivities prompted the exploration of the extraordinary chemical diversity associated with natural products. Recent studies involving nuclear receptors have disclosed a number of natural products as nuclear receptor ligands, serving to re-emphasize the translational possibilities of natural products in drug discovery. In this review, the natural ligands of nuclear receptors will be described with an emphasis on their mechanisms of action and their therapeutic potentials, as well as on strategies to determine potential marine natural products as nuclear receptor modulators.

  19. Serotonin receptors as cardiovascular targets

    NARCIS (Netherlands)

    C.M. Villalón (Carlos); P.A.M. de Vries (Peter); P.R. Saxena (Pramod Ranjan)

    1997-01-01

    textabstractSerotonin exerts complex effects in the cardiovascular system, including hypotension or hypertension, vasodilatation or vasoconstriction, and/or bradycardia or tachycardia; the eventual response depends primarily on the nature of the 5-HT receptors involved. In the light of current 5-HT

  20. NCS-1 associates with adenosine A2A receptors and modulates receptor function

    Directory of Open Access Journals (Sweden)

    Gemma eNavarro

    2012-04-01

    Full Text Available Modulation of G protein-coupled receptor (GPCR signalling by local changes in intracellular calcium concentration is an established function of Calmodulin which is known to interact with many GPCRs. Less is known about the functional role of the closely related neuronal EF-hand Ca2+-sensor proteins that frequently associate with calmodulin targets with different functional outcome. In the present study we aimed to investigate if a target of calmodulin – the A2A adenosine receptor, is able to associate with two other neuronal calcium binding proteins, namely NCS-1 and caldendrin. Using bioluminescence resonance energy transfer and co-immunoprecipitation experiments we show the existence of A2A - NCS-1 complexes in living cells whereas caldendrin did not associate with A2A receptors under the conditions tested. Interestingly, NCS-1 binding modulated downstream A2A receptor intracellular signalling in a Ca2+-dependent manner. Taken together this study provides further evidence that neuronal Ca2+-sensor proteins play an important role in modulation of GPCR signalling.

  1. Targeting the TAM Receptors in Leukemia

    Directory of Open Access Journals (Sweden)

    Madeline G. Huey

    2016-11-01

    Full Text Available Targeted inhibition of members of the TAM (TYRO-3, AXL, MERTK family of receptor tyrosine kinases has recently been investigated as a novel strategy for treatment of hematologic malignancies. The physiologic functions of the TAM receptors in innate immune control, natural killer (NK cell differentiation, efferocytosis, clearance of apoptotic debris, and hemostasis have previously been described and more recent data implicate TAM kinases as important regulators of erythropoiesis and megakaryopoiesis. The TAM receptors are aberrantly or ectopically expressed in many hematologic malignancies including acute myeloid leukemia, B- and T-cell acute lymphoblastic leukemia, chronic lymphocytic leukemia, and multiple myeloma. TAM receptors contribute to leukemic phenotypes through activation of pro-survival signaling pathways and interplay with other oncogenic proteins such as FLT3, LYN, and FGFR3. The TAM receptors also contribute to resistance to both cytotoxic chemotherapeutics and targeted agents, making them attractive therapeutic targets. A number of translational strategies for TAM inhibition are in development, including small molecule inhibitors, ligand traps, and monoclonal antibodies. Emerging areas of research include modulation of TAM receptors to enhance anti-tumor immunity, potential roles for TYRO-3 in leukemogenesis, and the function of the bone marrow microenvironment in mediating resistance to TAM inhibition.

  2. Endocrine receptors as targets for new drugs.

    Science.gov (United States)

    Altman, Jennifer

    2006-01-01

    Increasingly detailed knowledge of cellular signalling pathways is providing a sound basis for the development of specific drugs aimed at selected components of the pathways. Many of these targets are receptors and the multitude of hormone receptors makes endocrine functions a rich proving ground for this research. This article reviews a recent meeting (Insights into Receptor Function and New Drug Development Targets; 5th Endocrinology Colloquium of the Fondation Ipsen, Paris, December 5, 2005) where progress in defining suitable targets for drug therapies in the endocrine system and in designing drugs for some of these targets was discussed. Although the family of G-protein-coupled receptors, ubiquitous in the endocrine system, was the central focus, comparisons with other receptor families were made. Many mutations affecting genes coding for receptors or other components of signalling pathways have been found in a wide range of endocrine disorders including obesity, parathyroid malfunction, disorders involving thyroid-stimulating hormone and follicle-stimulating hormone, and tumours in the anterior pituitary, as well as in many types of cancer. These are being used to dissect the normal control mechanisms as well as to provide information for the development of selective drugs. Recently identified mutations that affect the intracellular traffic in newly synthesised receptors open up possibilities of another dimension of cellular regulation of signalling. Both the discovery of hormones such as apelin and its pairing with an 'orphan' receptor, and the unexpected action of a drug against cannabinoid receptors point to further levels of complexity in cardiovascular regulation. Deeper understanding of the evolution of receptor families and of the molecular mechanisms of signal transduction is enabling the design of highly specific agonists and antagonists. Pharmacological intervention is not limited to the ligand-receptor interaction but can extend to inhibition of

  3. The importance of the adenosine A(2A) receptor-dopamine D(2) receptor interaction in drug addiction.

    Science.gov (United States)

    Filip, M; Zaniewska, M; Frankowska, M; Wydra, K; Fuxe, K

    2012-01-01

    Drug addiction is a serious brain disorder with somatic, psychological, psychiatric, socio-economic and legal implications in the developed world. Illegal (e.g., psychostimulants, opioids, cannabinoids) and legal (alcohol, nicotine) drugs of abuse create a complex behavioral pattern composed of drug intake, withdrawal, seeking and relapse. One of the hallmarks of drugs that are abused by humans is that they have different mechanisms of action to increase dopamine (DA) neurotransmission within the mesolimbic circuitry of the brain and indirectly activate DA receptors. Among the DA receptors, D(2) receptors are linked to drug abuse and addiction because their function has been proven to be correlated with drug reinforcement and relapses. The recognition that D(2) receptors exist not only as homomers but also can form heteromers, such as with the adenosine (A)(2A) receptor, that are pharmacologically and functionally distinct from their constituent receptors, has significantly expanded the range of potential drug targets and provided new avenues for drug design in the search for novel drug addiction therapies. The aim of this review is to bring current focus on A(2A) receptors, their physiology and pharmacology in the central nervous system, and to discuss the therapeutic relevance of these receptors to drug addiction. We concentrate on the contribution of A(2A) receptors to the effects of different classes of drugs of abuse examined in preclinical behavioral experiments carried out with pharmacological and genetic tools. The consequences of chronic drug treatment on A(2A) receptor-assigned functions in preclinical studies are also presented. Finally, the neurochemical mechanism of the interaction between A(2A) receptors and drugs of abuse in the context of the heteromeric A(2A)-D(2) receptor complex is discussed. Taken together, a significant amount of experimental analyses provide evidence that targeting A(2A) receptors may offer innovative translational strategies

  4. Selectively targeting estrogen receptors for cancer treatment

    NARCIS (Netherlands)

    Shanle, Erin K.; Xu, Wei

    2010-01-01

    Estrogens regulate growth and development through the action of two distinct estrogen receptors (ERs), ER alpha and ER beta, which mediate proliferation and differentiation of cells. For decades, ER alpha mediated estrogen signaling has been therapeutically targeted to treat breast cancer, most nota

  5. Chemokine receptors: attractive targets for drug discovery.

    Science.gov (United States)

    Godessart, Nuria

    2005-06-01

    Studies of two antibodies, efalizumab and natalizumab, have recently demonstrated that the blockade of leukocyte migration is of therapeutic benefit for the treatment of diseases such as psoriasis and multiple sclerosis. The role of chemokines in the control of cell traffic led to their receptors being considered one of the most promising family of targets aimed at disrupting cell recruitment in chronic inflammatory processes. Choosing the appropriate chemokine receptor for each disease was not easy, and the interpretation of target validation studies proved to be extremely difficult. Despite an intense effort in the search for chemokine receptor antagonists in the last decade, no compounds in advanced clinical trials exist as such. The inherent complexity of the family, the differences between the chemokine system in mice and men, and the species selectivity of small-molecule compounds could account for this fact. Pharmaceutical companies still believe in chemokine receptors as therapeutic targets, as demonstrated by the number of compounds reported to be in development. In the next years, the developmental progression of these compounds will reveal which target within the chemokine family is of real therapeutic value.

  6. Targeted anticancer therapy: overexpressed receptors and nanotechnology.

    Science.gov (United States)

    Akhtar, Mohd Javed; Ahamed, Maqusood; Alhadlaq, Hisham A; Alrokayan, Salman A; Kumar, Sudhir

    2014-09-25

    Targeted delivery of anticancer drugs to cancer cells and tissues is a promising field due to its potential to spare unaffected cells and tissues, but it has been a major challenge to achieve success in these therapeutic approaches. Several innovative approaches to targeted drug delivery have been devised based on available knowledge in cancer biology and on technological advancements. To achieve the desired selectivity of drug delivery, nanotechnology has enabled researchers to design nanoparticles (NPs) to incorporate anticancer drugs and act as nanocarriers. Recently, many receptor molecules known to be overexpressed in cancer have been explored as docking sites for the targeting of anticancer drugs. In principle, anticancer drugs can be concentrated specifically in cancer cells and tissues by conjugating drug-containing nanocarriers with ligands against these receptors. Several mechanisms can be employed to induce triggered drug release in response to either endogenous trigger or exogenous trigger so that the anticancer drug is only released upon reaching and preferentially accumulating in the tumor tissue. This review focuses on overexpressed receptors exploited in targeting drugs to cancerous tissues and the tumor microenvironment. We briefly evaluate the structure and function of these receptor molecules, emphasizing the elegant mechanisms by which certain characteristics of cancer can be exploited in cancer treatment. After this discussion of receptors, we review their respective ligands and then the anticancer drugs delivered by nanotechnology in preclinical models of cancer. Ligand-functionalized nanocarriers have delivered significantly higher amounts of anticancer drugs in many in vitro and in vivo models of cancer compared to cancer models lacking such receptors or drug carrying nanocarriers devoid of ligand. This increased concentration of anticancer drug in the tumor site enabled by nanotechnology could have a major impact on the efficiency of cancer

  7. Cryostat for a 2 litre polarized target

    CERN Multimedia

    1982-01-01

    This target (world's largest) was meant for the muon scattering experiment NA2, then named NA9. It was prepared for use with NH3 in order to increase the amount or free hydrogen. Michel Rieubland (top, left), Tapio Niinikoski and Policella (bottom, centre and right).

  8. Target tracking using a 2D radar

    CSIR Research Space (South Africa)

    Kriel, M

    2012-08-01

    Full Text Available is omitted. This can be an important consideration as aircraft altitude limits the attack pro�les a target can��y [1]. 33.2 HEIGHT ESTIMATION The current literature regarding height estimation restricts itself to computations involving two or more 2D... is instrumental in determining the aircraft altitude. The accuracy to which these speeds are known is directly pro- portional to the accuracy to which the altitude can be determined. Knowledge of aircraft speed can be obtained in a variety of ways. For example...

  9. Adenosine A2A Receptors Modulate Acute Injury and Neuroinflammation in Brain Ischemia.

    OpenAIRE

    Felicita Pedata; Anna Maria Pugliese; Elisabetta Coppi; Ilaria Dettori; Giovanna Maraula; Lucrezia Cellai; Alessia Melani

    2014-01-01

    The extracellular concentration of adenosine in the brain increases dramatically during ischemia. Adenosine A2A receptor is expressed in neurons and glial cells and in inflammatory cells (lymphocytes and granulocytes). Recently, adenosine A2A receptor emerged as a potential therapeutic attractive target in ischemia. Ischemia is a multifactorial pathology characterized by different events evolving in the time. After ischemia the early massive increase of extracellular glutamate is followed by ...

  10. Adenosine A2B receptor: from cell biology to human diseases

    Science.gov (United States)

    Sun, Ying; Huang, Pingbo

    2016-08-01

    Extracellular adenosine is a ubiquitous signaling molecule that modulates a wide array of biological processes. Recently, significant advances have been made in our understanding of A2B adenosine receptor (A2BAR). In this review, we first summarize some of the general characteristics of A2BAR, and then we describe the multiple binding partners of the receptor, such as newly identified α-actinin-1 and p105, and discuss how these associated proteins could modulate A2BAR’s functions, including certain seemingly paradoxical functions of the receptor. Growing evidence indicates a critical role of A2BAR in cancer, renal disease, and diabetes, in addition to its importance in the regulation of vascular diseases and lung disease. Here, we also discuss the role of A2BAR in cancer, renal disease, and diabetes and the potential of the receptor as a target for treating these three diseases.

  11. Targeted Radiotherapy of Estrogen Receptor Positive Tumors

    Energy Technology Data Exchange (ETDEWEB)

    Raghavan Rajagopalan

    2006-08-31

    The overall objectives of the proposal were to develop estrogen receptor (ER) binding small molecule radiopharmaceuticals for targeted radiotherapy of ER positive (ER+) tumors. In particular, this proposal focused on embedding a {sup 186,188}Re or a {sup 32}P radionuclide into an estrogen steroidal framework by isosteric substitution such that the resulting structure is topologically similar to the estrogen (estrogen mimic). The estrogen mimic molecules expected to bind to the ER and exhibit biodistribution akin to that of native estrogen due to structural mimicry. It is anticipated that the {sup 186,188}Re- or a {sup 32}P-containing estrogen mimics will be useful for targeted molecular radiotherapy of ER+ tumors. It is well established that the in vivo target tissue uptake of estrogen like steroidal molecules is related to the binding of the steroids to sex hormone binding globulin (SHBG). SHBG is important in the uptake of estrogens and testosterone in target tissues by SHBG receptors on the cell surface. However, hitherto the design of estrogen like small molecule radiopharmaceuticals was focused on optimizing ER binding characteristics without emphasis on SHBG binding properties. Consequently, even the molecules with good ER affinity in vitro, performed poorly in biodistribution studies. Based on molecular modeling studies the proposal focused on developing estrogen mimics 1-3 which were topologically similar to native estrogens, and form hydrogen bonds in ER and SHBG in the same manner as those of native estrogens. To this end the technical objectives of the proposal focused on synthesizing the rhenium-estrone and estradiol mimics 1 and 2 respectively, and phosphorous estradiol mimic 3 and to assess their stability and in vitro binding characteristics to ER and SHBG.

  12. Targeted Radiotherapy of Estrogen Receptor Positive Tumors

    Energy Technology Data Exchange (ETDEWEB)

    Raghavan Rajagopalan

    2006-08-31

    The overall objectives of the proposal were to develop estrogen receptor (ER) binding small molecule radiopharmaceuticals for targeted radiotherapy of ER positive (ER+) tumors. In particular, this proposal focused on embedding a {sup 186,188}Re or a {sup 32}P radionuclide into an estrogen steroidal framework by isosteric substitution such that the resulting structure is topologically similar to the estrogen (estrogen mimic). The estrogen mimic molecules expected to bind to the ER and exhibit biodistribution akin to that of native estrogen due to structural mimicry. It is anticipated that the {sup 186,188}Re- or a {sup 32}P-containing estrogen mimics will be useful for targeted molecular radiotherapy of ER+ tumors. It is well established that the in vivo target tissue uptake of estrogen like steroidal molecules is related to the binding of the steroids to sex hormone binding globulin (SHBG). SHBG is important in the uptake of estrogens and testosterone in target tissues by SHBG receptors on the cell surface. However, hitherto the design of estrogen like small molecule radiopharmaceuticals was focused on optimizing ER binding characteristics without emphasis on SHBG binding properties. Consequently, even the molecules with good ER affinity in vitro, performed poorly in biodistribution studies. Based on molecular modeling studies the proposal focused on developing estrogen mimics 1-3 which were topologically similar to native estrogens, and form hydrogen bonds in ER and SHBG in the same manner as those of native estrogens. To this end the technical objectives of the proposal focused on synthesizing the rhenium-estrone and estradiol mimics 1 and 2 respectively, and phosphorous estradiol mimic 3 and to assess their stability and in vitro binding characteristics to ER and SHBG.

  13. Anti-phospholipase A2 receptor antibody in membranous nephropathy.

    Science.gov (United States)

    Qin, Weisong; Beck, Laurence H; Zeng, Caihong; Chen, Zhaohong; Li, Shijun; Zuo, Ke; Salant, David J; Liu, Zhihong

    2011-06-01

    The M-type phospholipase A2 receptor (PLA2R) is a target autoantigen in adult idiopathic membranous nephropathy (MN), but the prevalence of autoantibodies against PLA2R is unknown among Chinese patients with MN. Here, we measured anti-PLA2R antibody in the serum of 60 patients with idiopathic MN, 20 with lupus-associated MN, 16 with hepatitis B (HBV)-associated MN, and 10 with tumor-associated MN. Among patients with idiopathic MN, 49 (82%) had detectable anti-PLA2R autoantibodies using a Western blot assay; an assay with greater sensitivity detected very low titers of anti-PLA2R in 10 of the remaining 11 patients. Using the standard assay, we detected anti-PLA2R antibody in only 1 patient with lupus, 1 with HBV, and 3 with cancer, producing an overall specificity of 89% in this cohort limited to patients with secondary MN. The enhanced assay detected low titers of anti-PLA2R in only 2 additional samples of HBV-associated MN. In summary, these results suggest that PLA2R is a major target antigen in Chinese idiopathic MN and that detection of anti-PLA2R is a sensitive test for idiopathic MN.

  14. Recent developments in receptor tyrosine kinases targeted anticancer therapy

    Directory of Open Access Journals (Sweden)

    Samir H. Raval

    2016-01-01

    Full Text Available Novel concepts and understanding of receptors lead to discoveries and optimization of many small molecules and antibodies as anti-cancerous drugs. Receptor tyrosine kinases (RTKs are such a promising class of receptors under the investigation in past three decades. RTKs are one of the essential mediators of cell signaling mechanism for various cellular processes. Transformations such as overexpression, dysregulation, or mutations of RTKs may result into malignancy, and thus are an important target for anticancer therapy. Numerous subfamilies of RTKs, such as epidermal growth factor receptor, vascular endothelial growth factor receptor, fibroblast growth factor receptors, insulin-like growth factor receptor, and hepatocyte growth factor receptor, have been being investigated in recent years as target for anticancer therapy. The present review focuses several small molecules drugs as well as monoclonal antibodies targeting aforesaid subfamilies either approved or under investigation to treat the various cancers.

  15. Key modulatory role of presynaptic adenosine A2A receptors in cortical neurotransmission to the striatal direct pathway.

    Science.gov (United States)

    Quiroz, César; Luján, Rafael; Uchigashima, Motokazu; Simoes, Ana Patrícia; Lerner, Talia N; Borycz, Janusz; Kachroo, Anil; Canas, Paula M; Orru, Marco; Schwarzschild, Michael A; Rosin, Diane L; Kreitzer, Anatol C; Cunha, Rodrigo A; Watanabe, Masahiko; Ferré, Sergi

    2009-11-18

    Basal ganglia processing results from a balanced activation of direct and indirect striatal efferent pathways, which are controlled by dopamine D1 and D2 receptors, respectively. Adenosine A2A receptors are considered novel antiparkinsonian targets, based on their selective postsynaptic localization in the indirect pathway, where they modulate D2 receptor function. The present study provides evidence for the existence of an additional, functionally significant, segregation of A2A receptors at the presynaptic level. Using integrated anatomical, electrophysiological, and biochemical approaches, we demonstrate that presynaptic A2A receptors are preferentially localized in cortical glutamatergic terminals that contact striatal neurons of the direct pathway, where they exert a selective modulation of corticostriatal neurotransmission. Presynaptic striatal A2A receptors could provide a new target for the treatment of neuropsychiatric disorders.

  16. Adenosine A2A Receptors Modulate Acute Injury and Neuroinflammation in Brain Ischemia

    Directory of Open Access Journals (Sweden)

    Felicita Pedata

    2014-01-01

    Full Text Available The extracellular concentration of adenosine in the brain increases dramatically during ischemia. Adenosine A2A receptor is expressed in neurons and glial cells and in inflammatory cells (lymphocytes and granulocytes. Recently, adenosine A2A receptor emerged as a potential therapeutic attractive target in ischemia. Ischemia is a multifactorial pathology characterized by different events evolving in the time. After ischemia the early massive increase of extracellular glutamate is followed by activation of resident immune cells, that is, microglia, and production or activation of inflammation mediators. Proinflammatory cytokines, which upregulate cell adhesion molecules, exert an important role in promoting recruitment of leukocytes that in turn promote expansion of the inflammatory response in ischemic tissue. Protracted neuroinflammation is now recognized as the predominant mechanism of secondary brain injury progression. A2A receptors present on central cells and on blood cells account for important effects depending on the time-related evolution of the pathological condition. Evidence suggests that A2A receptor antagonists provide early protection via centrally mediated control of excessive excitotoxicity, while A2A receptor agonists provide protracted protection by controlling massive blood cell infiltration in the hours and days after ischemia. Focus on inflammatory responses provides for adenosine A2A receptor agonists a wide therapeutic time-window of hours and even days after stroke.

  17. Mitochondrial T3 receptor and targets.

    Science.gov (United States)

    Wrutniak-Cabello, Chantal; Casas, François; Cabello, Gérard

    2017-02-03

    The demonstration that TRα1 mRNA encodes a nuclear thyroid hormone receptor and two proteins imported into mitochondria with molecular masses of 43 and 28 kDa has brought new clues to better understand the pleiotropic influence of iodinated hormones. If p28 activity remains unknown, p43 binds to T3 responsive elements occurring in the organelle genome, and, in the T3 presence, stimulates mitochondrial transcription and the subsequent synthesis of mitochondrial encoded proteins. This influence increases mitochondrial activity and through changes in the mitochondrial/nuclear cross talk affects important nuclear target genes regulating cell proliferation and differentiation, oncogenesis, or apoptosis. In addition, this pathway influences muscle metabolic and contractile phenotype, as well as glycaemia regulation. Interestingly, according to the process considered, p43 exerts opposite or cooperative effects with the well-known T3 pathway, thus allowing a fine tuning of the physiological influence of this hormone. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. New receptor targeted drugs : pharmaceutical aspects and molecular imaging

    NARCIS (Netherlands)

    Lub-de Hooge, Marjolijn Nicolette

    2006-01-01

    A new generation of innovative receptor targeted drugs rapidly enters the market. However, since these drugs target a specific receptor, they are not of value for all cancer patients, but only for specific tumor types or a subset within a tumor type. This makes it increasingly important to select

  19. Discoidin Domain Receptors: Novel Targets in Breast Cancer Bone Metastasis

    Science.gov (United States)

    2017-02-01

    AWARD NUMBER: W81XWH-16-1-0046 TITLE: Discoidin Domain Receptors: Novel Targets in Breast Cancer Bone Metastasis PRINCIPAL INVESTIGATOR: Dr...TITLE AND SUBTITLE 5a. CONTRACT NUMBER Discoidin Domain Receptors: Novel Targets in Breast Cancer Bone Metastasis 5b. GRANT NUMBER W81XWH-16-1-0046 5c...14. ABSTRACT Here we report major findings for our project aimed at studying the expression of Discoidin Domain Receptors (DDRs) in breast cancer

  20. Review: Receptor Targeted Nuclear Imaging of Breast Cancer.

    Science.gov (United States)

    Dalm, Simone U; Verzijlbergen, John Fred; De Jong, Marion

    2017-01-26

    Receptor targeted nuclear imaging directed against molecular markers overexpressed on breast cancer (BC) cells offers a sensitive and specific method for BC imaging. Currently, a few targets such as estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2), somatostatin receptor (SSTR), and the gastrin releasing peptide receptor (GRPR) are being investigated for this purpose. Expression of these targets is BC subtype dependent and information that can be gained from lesion visualization is dependent on the target; ER-targeting radiotracers, e.g., can be used to monitor response to anti-estrogen treatment. Here we give an overview of the studies currently under investigation for receptor targeted nuclear imaging of BC. Main findings of imaging studies are summarized and (potential) purposes of lesion visualization by targeting these molecular markers are discussed. Since BC is a very heterogeneous disease and molecular target expression can vary per subtype, but also during disease progression or under influence of treatment, radiotracers for selected imaging purposes should be chosen carefully.

  1. Review: Receptor Targeted Nuclear Imaging of Breast Cancer

    Science.gov (United States)

    Dalm, Simone U.; Verzijlbergen, John Fred; De Jong, Marion

    2017-01-01

    Receptor targeted nuclear imaging directed against molecular markers overexpressed on breast cancer (BC) cells offers a sensitive and specific method for BC imaging. Currently, a few targets such as estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2), somatostatin receptor (SSTR), and the gastrin releasing peptide receptor (GRPR) are being investigated for this purpose. Expression of these targets is BC subtype dependent and information that can be gained from lesion visualization is dependent on the target; ER-targeting radiotracers, e.g., can be used to monitor response to anti-estrogen treatment. Here we give an overview of the studies currently under investigation for receptor targeted nuclear imaging of BC. Main findings of imaging studies are summarized and (potential) purposes of lesion visualization by targeting these molecular markers are discussed. Since BC is a very heterogeneous disease and molecular target expression can vary per subtype, but also during disease progression or under influence of treatment, radiotracers for selected imaging purposes should be chosen carefully. PMID:28134770

  2. Epidermal growth factor receptor: Target for delivery and silencing

    NARCIS (Netherlands)

    Santos Oliveira, S.

    2008-01-01

    Epidermal growth factor receptor in cancer therapy Recently, cancer research has been able to identify molecular targets that are specific for (or highly expressed by) cancer cells. These molecular targets serve as models for the development of rationally designed anticancer drugs that target import

  3. Striatal adenosine-cannabinoid receptor interactions in rats over-expressing adenosine A2A receptors.

    Science.gov (United States)

    Chiodi, Valentina; Ferrante, Antonella; Ferraro, Luca; Potenza, Rosa Luisa; Armida, Monica; Beggiato, Sarah; Pèzzola, Antonella; Bader, Michael; Fuxe, Kjell; Popoli, Patrizia; Domenici, Maria Rosaria

    2016-03-01

    Adenosine A2A receptors (A2 A Rs) and cannabinoid CB1 receptors (CB1 Rs) are highly expressed in the striatum, where they functionally interact and form A2A /CB1 heteroreceptor complexes. We investigated the effects of CB1 R stimulation in a transgenic rat strain over-expressing A2 A Rs under the control of the neural-specific enolase promoter (NSEA2A rats) and in age-matched wild-type (WT) animals. The effects of the CB1 R agonist WIN 55,212-2 (WIN) were significantly lower in NSEA2A rats than in WT animals, as demonstrated by i) electrophysiological recordings of synaptic transmission in corticostriatal slices; ii) the measurement of glutamate outflow from striatal synaptosomes and iii) in vivo experiments on locomotor activity. Moreover, while the effects of WIN were modulated by both A2 A R agonist (CGS 21680) and antagonists (ZM 241385, KW-6002 and SCH-442416) in WT animals, the A2 A R antagonists failed to influence WIN-mediated effects in NSEA2A rats. The present results demonstrate that in rats with genetic neuronal over-expression of A2 A Rs, the effects mediated by CB1 R activation in the striatum are significantly reduced, suggesting a change in the stoichiometry of A2A and CB1 receptors and providing a strategy to dissect the involvement of A2 A R forming or not forming heteromers in the modulation of striatal functions. These findings add additional evidence for the existence of an interaction between striatal A2 A Rs and CB1 Rs, playing a fundamental role in the regulation of striatal functions. We studied A2A -CB1 receptor interaction in transgenic rats over-expressing adenosine A2A receptors under the control of the neuron-specific enolase promoter (NSEA2A ). In these rats, we demonstrated a reduced effect of the CB1 receptor agonist WIN 55,212-2 in the modulation of corticostriatal synaptic transmission and locomotor activity, while CB1 receptor expression level did not change with respect to WT rats. A reduction in the expression of A2A -CB1

  4. Carbamate Insecticides Target Human Melatonin Receptors.

    Science.gov (United States)

    Popovska-Gorevski, Marina; Dubocovich, Margarita L; Rajnarayanan, Rajendram V

    2017-02-20

    Carbaryl (1-naphthyl methylcarbamate) and carbofuran (2,3-dihydro-2,2-dimethyl-7-benzofuranyl methylcarbamate) are among the most toxic insecticides, implicated in a variety of diseases including diabetes and cancer among others. Using an integrated pharmacoinformatics based screening approach, we have identified these insecticides to be structural mimics of the neurohormone melatonin and were able to bind to the putative melatonin binding sites in MT1 and MT2 melatonin receptors in silico. Carbaryl and carbofuran then were tested for competition with 2-[(125)I]-iodomelatonin (300 pM) binding to hMT1 or hMT2 receptors stably expressed in CHO cells. Carbaryl and carbofuran showed higher affinity for competition with 2-[(125)I]-iodomelatonin binding to the hMT2 compared to the hMT1 melatonin receptor (33 and 35-fold difference, respectively) as predicted by the molecular modeling. In the presence of GTP (100 μM), which decouples the G-protein linked receptors to modulate signaling, the apparent efficacy of carbaryl and carbofuran for 2-[(125)I]-iodomelatonin binding for the hMT1 melatonin receptor was not affected but significantly decreased for the hMT2 melatonin receptor compatible with receptor antagonist/inverse agonist and agonist efficacy, respectively. Altogether, our data points to a potentially new mechanism through which carbamate insecticides carbaryl and carbofuran could impact human health by altering the homeostatic balance of key regulatory processes by directly binding to melatonin receptors.

  5. A2A adenosine receptor antagonism enhances synaptic and motor effects of cocaine via CB1 cannabinoid receptor activation.

    Directory of Open Access Journals (Sweden)

    Alessandro Tozzi

    Full Text Available BACKGROUND: Cocaine increases the level of endogenous dopamine (DA in the striatum by blocking the DA transporter. Endogenous DA modulates glutamatergic inputs to striatal neurons and this modulation influences motor activity. Since D2 DA and A2A-adenosine receptors (A2A-Rs have antagonistic effects on striatal neurons, drugs targeting adenosine receptors such as caffeine-like compounds, could enhance psychomotor stimulant effects of cocaine. In this study, we analyzed the electrophysiological effects of cocaine and A2A-Rs antagonists in striatal slices and the motor effects produced by this pharmacological modulation in rodents. PRINCIPAL FINDINGS: Concomitant administration of cocaine and A2A-Rs antagonists reduced glutamatergic synaptic transmission in striatal spiny neurons while these drugs failed to produce this effect when given in isolation. This inhibitory effect was dependent on the activation of D2-like receptors and the release of endocannabinoids since it was prevented by L-sulpiride and reduced by a CB1 receptor antagonist. Combined application of cocaine and A2A-R antagonists also reduced the firing frequency of striatal cholinergic interneurons suggesting that changes in cholinergic tone might contribute to this synaptic modulation. Finally, A2A-Rs antagonists, in the presence of a sub-threshold dose of cocaine, enhanced locomotion and, in line with the electrophysiological experiments, this enhanced activity required activation of D2-like and CB1 receptors. CONCLUSIONS: The present study provides a possible synaptic mechanism explaining how caffeine-like compounds could enhance psychomotor stimulant effects of cocaine.

  6. [G-protein-coupled receptors targeting: the allosteric approach].

    Science.gov (United States)

    Sebag, Julien A; Pantel, Jacques

    2012-10-01

    G-protein-coupled receptors (GPCR) are a major family of drug targets. Essentially all drugs targeting these receptors on the market compete with the endogenous ligand (agonists or antagonists) for binding the receptor. Recently, non-competitive compounds binding to distinct sites from the cognate ligand were documented in various classes of these receptors. These compounds, called allosteric modulators, generally endowed of a better selectivity are able to modulate specifically the endogenous signaling of the receptor. To better understand the promising potential of this class of GPCRs targeting compounds, this review highlights the properties of allosteric modulators, the strategies used to identify them and the challenges associated with the development of these compounds.

  7. Silencing Receptor EphA2 Enhanced Sensitivity to Lipoplatin™ in Lung Tumor and MPM Cells.

    Science.gov (United States)

    Lee, Hung-Yen; Mohammed, Kamal A; Goldberg, Eugene P; Kaye, Frederic; Najmunnisa, Nasreen

    2016-08-08

    Receptor EphA2 is overexpressed in lung cancer and malignant pleural mesothelioma (MPM) which promote tumorogenesis. Lipoplatin™, a new liposomal cisplatin formulation, is used against resistant tumors. Use of cisplatin-based drugs leads to unacceptable toxicities. To improve the effectiveness of Lipoplatin, enhancing the cellular sensitivity of lung tumor and MPM cells is critical. Therefore, we targeted receptor EphA2 by silencing interference RNA (siRNA) and treated tumor cells with Lipoplatin. The combined effects of siRNA-EphA2 and Lipoplatin were determined. We report that silencing EphA2 significantly enhanced the cellular sensitivity of lung tumor and MPM cells to Lipoplatin and maybe a potential therapy for lung cancer.

  8. Androgen Receptor: A Complex Therapeutic Target for Breast Cancer

    Directory of Open Access Journals (Sweden)

    Ramesh Narayanan

    2016-12-01

    Full Text Available Molecular and histopathological profiling have classified breast cancer into multiple sub-types empowering precision treatment. Although estrogen receptor (ER and human epidermal growth factor receptor (HER2 are the mainstay therapeutic targets in breast cancer, the androgen receptor (AR is evolving as a molecular target for cancers that have developed resistance to conventional treatments. The high expression of AR in breast cancer and recent discovery and development of new nonsteroidal drugs targeting the AR provide a strong rationale for exploring it again as a therapeutic target in this disease. Ironically, both nonsteroidal agonists and antagonists for the AR are undergoing clinical trials, making AR a complicated target to understand in breast cancer. This review provides a detailed account of AR’s therapeutic role in breast cancer.

  9. Androgen Receptor: A Complex Therapeutic Target for Breast Cancer.

    Science.gov (United States)

    Narayanan, Ramesh; Dalton, James T

    2016-12-02

    Molecular and histopathological profiling have classified breast cancer into multiple sub-types empowering precision treatment. Although estrogen receptor (ER) and human epidermal growth factor receptor (HER2) are the mainstay therapeutic targets in breast cancer, the androgen receptor (AR) is evolving as a molecular target for cancers that have developed resistance to conventional treatments. The high expression of AR in breast cancer and recent discovery and development of new nonsteroidal drugs targeting the AR provide a strong rationale for exploring it again as a therapeutic target in this disease. Ironically, both nonsteroidal agonists and antagonists for the AR are undergoing clinical trials, making AR a complicated target to understand in breast cancer. This review provides a detailed account of AR's therapeutic role in breast cancer.

  10. Death receptors: Targets for cancer therapy

    Energy Technology Data Exchange (ETDEWEB)

    Mahmood, Zafar [Proteomics Laboratory, Indian Institute of Toxicology Research, Mahatma Gandhi Marg, Lucknow 226001 (India); Shukla, Yogeshwer, E-mail: yogeshwer_shukla@hotmail.com [Proteomics Laboratory, Indian Institute of Toxicology Research, Mahatma Gandhi Marg, Lucknow 226001 (India)

    2010-04-01

    Apoptosis is the cell's intrinsic program to death, which plays an important role in physiologic growth control and homeostasis. Apoptosis can be triggered by death receptors (DRs), without any adverse effects. DRs are the members of tumor necrosis factor (TNF) receptor superfamily, known to be involved in apoptosis signaling, independent of p53 tumor-supressor gene. Selective triggering of DR-mediated apoptosis in cancer cells is a novel approach in cancer therapy. So far, the best characterized DRs are CD95 (Fas/Apo1), TNF-related apoptosis-inducing ligand receptor (TRAILR) and tumor necrosis factor receptor (TNFR). Among these, TRAILR is emerging as most promising agent for cancer therapy, because it induces apoptosis in a variety of tumor and transformed cells without any toxicity to normal cells. TRAIL treatment in combination with chemotherapy or radiotherapy enhances TRAIL sensitivity or reverses TRAIL resistance by regulating downstream effectors. This review covers the current knowledge about the DRs, summarizes main signaling in DRs and also summarizes the preclinical approaches of these DRs in cancer therapy.

  11. Folate receptor targeted liposomes encapsulating anti-cancer drugs.

    Science.gov (United States)

    Chaudhury, Anumita; Das, Surajit

    2015-01-01

    Among all available lipid based nanoparticulate systems, the success of liposomal drug delivery system is evident by the number of liposomal products available in the market or under advanced stages of preclinical and clinical trials. Liposome has the ability to deliver chemotherapeutic agents to the targeted tissues or even inside the cancerous cells by enhanced intracellular penetration or improved tumour targeting. In the last decade, folate receptor mediated tumour targeting has emerged as an attractive alternative method of active targeting of cancer cells through liposomes due to its numerous advantages over other targeting methods. Folate receptors, also known as folate binding proteins, allow the binding and internalization of folate or folic acid into the cells by a method called folate receptor mediated endocytosis. They have restricted presence in normal cells and are mostly expressed during malignant transformation. In this review article, folate receptor targeting capability of liposomes has been described. This review article has focussed on the different cancer drugs which have been encapsulated in folate receptor targeted liposomes and their in vitro as well as in vivo efficacies in several tumour models.

  12. The A2B adenosine receptor protects against inflammation and excessive vascular adhesion

    Science.gov (United States)

    Yang, Dan; Zhang, Ying; Nguyen, Hao G.; Koupenova, Milka; Chauhan, Anil K.; Makitalo, Maria; Jones, Matthew R.; Hilaire, Cynthia St.; Seldin, David C.; Toselli, Paul; Lamperti, Edward; Schreiber, Barbara M.; Gavras, Haralambos; Wagner, Denisa D.; Ravid, Katya

    2006-01-01

    Adenosine has been described as playing a role in the control of inflammation, but it has not been certain which of its receptors mediate this effect. Here, we generated an A2B adenosine receptor–knockout/reporter gene–knock-in (A2BAR-knockout/reporter gene–knock-in) mouse model and showed receptor gene expression in the vasculature and macrophages, the ablation of which causes low-grade inflammation compared with age-, sex-, and strain-matched control mice. Augmentation of proinflammatory cytokines, such as TNF-α, and a consequent downregulation of IκB-α are the underlying mechanisms for an observed upregulation of adhesion molecules in the vasculature of these A2BAR-null mice. Intriguingly, leukocyte adhesion to the vasculature is significantly increased in the A2BAR-knockout mice. Exposure to an endotoxin results in augmented proinflammatory cytokine levels in A2BAR-null mice compared with control mice. Bone marrow transplantations indicated that bone marrow (and to a lesser extent vascular) A2BARs regulate these processes. Hence, we identify the A2BAR as a new critical regulator of inflammation and vascular adhesion primarily via signals from hematopoietic cells to the vasculature, focusing attention on the receptor as a therapeutic target. PMID:16823489

  13. Quantity and accessibility for specific targeting of receptors in tumours

    Science.gov (United States)

    Hussain, Sajid; Rodriguez-Fernandez, Maria; Braun, Gary B.; Doyle, Francis J.; Ruoslahti, Erkki

    2014-06-01

    Synaphic (ligand-directed) targeting of drugs is an important potential new approach to drug delivery, particularly in oncology. Considerable success with this approach has been achieved in the treatment of blood-borne cancers, but the advances with solid tumours have been modest. Here, we have studied the number and availability for ligand binding of the receptors for two targeting ligands. The results show that both paucity of total receptors and their poor availability are major bottlenecks in drug targeting. A tumour-penetrating peptide greatly increases the availability of receptors by promoting transport of the drug to the extravascular tumour tissue, but the number of available receptors still remains low, severely limiting the utility of the approach. Our results emphasize the importance of using drugs with high specific activity to avoid exceeding receptor capacity because any excess drug conjugate would lose the targeting advantage. The mathematical models we describe make it possible to focus on those aspects of the targeting mechanism that are most likely to have a substantial effect on the overall efficacy of the targeting.

  14. Structure-based receptor MIMICS targeted against bacterial superantigen toxins

    Science.gov (United States)

    Gupta, Goutam; Hong-Geller, Elizabeth; Shiflett, Patrick R.; Lehnert, Nancy M.

    2009-08-18

    The invention provides therapeutic compositions useful in the treatment of bacterial superantigen mediated conditions, such as Toxic Shock Syndrome. The compositions comprise genetically engineered bifunctional polypeptides containing a specific T-cell receptor binding domain and a specific MHC class II receptor binding domain, each targeting non-overlapping epitopes on a superantigen molecule against which they are designed. The anti-superantigen "receptor mimetics" or "chimeras" are rationally designed to recreate the modality of superantigen binding directly to both the TCR and the MHC-II receptor, and are capable of acting as decoys for superantigen binding, effectively out-competing the host T-cell and MHC-II receptors, the natural host receptors.

  15. Conotoxins Targeting Nicotinic Acetylcholine Receptors: An Overview

    OpenAIRE

    2014-01-01

    Marine snails of the genus Conus are a large family of predatory gastropods with an unparalleled molecular diversity of pharmacologically active compounds in their venom. Cone snail venom comprises of a rich and diverse cocktail of peptide toxins which act on a wide variety of ion channels such as voltage-gated sodium- (NaV), potassium- (KV), and calcium- (CaV) channels as well as nicotinic acetylcholine receptors (nAChRs) which are classified as ligand-gated ion channels. The mode of action ...

  16. Conotoxins Targeting Nicotinic Acetylcholine Receptors: An Overview

    Directory of Open Access Journals (Sweden)

    Eline K. M. Lebbe

    2014-05-01

    Full Text Available Marine snails of the genus Conus are a large family of predatory gastropods with an unparalleled molecular diversity of pharmacologically active compounds in their venom. Cone snail venom comprises of a rich and diverse cocktail of peptide toxins which act on a wide variety of ion channels such as voltage-gated sodium- (NaV, potassium- (KV, and calcium- (CaV channels as well as nicotinic acetylcholine receptors (nAChRs which are classified as ligand-gated ion channels. The mode of action of several conotoxins has been the subject of investigation, while for many others this remains unknown. This review aims to give an overview of the knowledge we have today on the molecular pharmacology of conotoxins specifically interacting with nAChRs along with the structure–function relationship data.

  17. Receptor-Mediated Drug Delivery Systems Targeting to Glioma

    Directory of Open Access Journals (Sweden)

    Shanshan Wang

    2015-12-01

    Full Text Available Glioma has been considered to be the most frequent primary tumor within the central nervous system (CNS. The complexity of glioma, especially the existence of the blood-brain barrier (BBB, makes the survival and prognosis of glioma remain poor even after a standard treatment based on surgery, radiotherapy, and chemotherapy. This provides a rationale for the development of some novel therapeutic strategies. Among them, receptor-mediated drug delivery is a specific pattern taking advantage of differential expression of receptors between tumors and normal tissues. The strategy can actively transport drugs, such as small molecular drugs, gene medicines, and therapeutic proteins to glioma while minimizing adverse reactions. This review will summarize recent progress on receptor-mediated drug delivery systems targeting to glioma, and conclude the challenges and prospects of receptor-mediated glioma-targeted therapy for future applications.

  18. AMPA receptor pHluorin-GluA2 reports NMDA receptor-induced intracellular acidification in hippocampal neurons

    DEFF Research Database (Denmark)

    Rathje, Mette; Fang, Huaqiang; Bachman, Julia L;

    2013-01-01

    NMDA receptor activation promotes endocytosis of AMPA receptors, which is an important mechanism underlying long-term synaptic depression. The pH-sensitive GFP variant pHluorin fused to the N terminus of GluA2 (pH-GluA2) has been used to assay NMDA-mediated AMPA receptor endocytosis and recycling...

  19. Peroxisome Proliferator-Activated Receptor Alpha Target Genes

    OpenAIRE

    Maryam Rakhshandehroo; Bianca Knoch; Michael Müller; Sander Kersten

    2010-01-01

    The peroxisome proliferator-activated receptor alpha (PPAR alpha) is a ligand-activated transcription factor involved in the regulation of a variety of processes, ranging from inflammation and immunity to nutrient metabolism and energy homeostasis. PPAR alpha serves as a molecular target for hypolipidemic fibrates drugs which bind the receptor with high affinity. Furthermore, PPAR alpha binds and is activated by numerous fatty acids and fatty acid-derived compounds. PPAR alpha governs biologi...

  20. Cholecystokinin and gastrin receptors targeting in gastrointestinal cancer.

    Science.gov (United States)

    Rai, Rajani; Chandra, Vishal; Tewari, Mallika; Kumar, Mohan; Shukla, Hari S

    2012-12-01

    Cholecystokinin and Gastrin are amongst the first gastrointestinal hormone discovered. In addition to classical actions (contraction of gallbladder, growth and secretion in the stomach and pancreas), these also act as growth stimulants for gastrointestinal malignancies and cell lines. Growth of these tumours is inhibited by antagonists of the cholecystokinin and gastrin receptors. These receptors provides most promising approach in clinical oncology and several specific radiolabelled ligands have been synthesized for specific tumour targeting and therapy of tumours overexpressing these receptors. Therefore, definition of the molecular structure of the receptor involved in the autocrine/paracrine loop may contribute to novel therapies for gastrointestinal cancer. Hence, this review tries to focus on the role and distribution of these hormones and their receptors in gastrointestinal cancer with a brief talk about the clinical trial using available agonist and antagonist in gastrointestinal cancers.

  1. Targeted Silencing of Anthrax Toxin Receptors Protects against Anthrax Toxins*

    Science.gov (United States)

    Arévalo, Maria T.; Navarro, Ashley; Arico, Chenoa D.; Li, Junwei; Alkhatib, Omar; Chen, Shan; Diaz-Arévalo, Diana; Zeng, Mingtao

    2014-01-01

    Anthrax spores can be aerosolized and dispersed as a bioweapon. Current postexposure treatments are inadequate at later stages of infection, when high levels of anthrax toxins are present. Anthrax toxins enter cells via two identified anthrax toxin receptors: tumor endothelial marker 8 (TEM8) and capillary morphogenesis protein 2 (CMG2). We hypothesized that host cells would be protected from anthrax toxins if anthrax toxin receptor expression was effectively silenced using RNA interference (RNAi) technology. Thus, anthrax toxin receptors in mouse and human macrophages were silenced using targeted siRNAs or blocked with specific antibody prior to challenge with anthrax lethal toxin. Viability assays were used to assess protection in macrophages treated with specific siRNA or antibody as compared with untreated cells. Silencing CMG2 using targeted siRNAs provided almost complete protection against anthrax lethal toxin-induced cytotoxicity and death in murine and human macrophages. The same results were obtained by prebinding cells with specific antibody prior to treatment with anthrax lethal toxin. In addition, TEM8-targeted siRNAs also offered significant protection against lethal toxin in human macrophage-like cells. Furthermore, silencing CMG2, TEM8, or both receptors in combination was also protective against MEK2 cleavage by lethal toxin or adenylyl cyclase activity by edema toxin in human kidney cells. Thus, anthrax toxin receptor-targeted RNAi has the potential to be developed as a life-saving, postexposure therapy against anthrax. PMID:24742682

  2. Targeting thyroid diseases with TSH receptor analogs.

    Science.gov (United States)

    Galofré, Juan C; Chacón, Ana M; Latif, Rauf

    2013-12-01

    The thyroid-stimulating hormone (TSH) receptor (TSHR) is a major regulator of thyroid function and growth, and is the key antigen in several pathological conditions including hyperthyroidism, hypothyroidism, and thyroid tumors. Various effective treatment strategies are currently available for many of these clinical conditions such as antithyroid drugs or radioiodine therapy, but they are not devoid of side effects. In addition, treatment of complications of Graves' disease such as Graves' ophthalmopathy is often difficult and unsatisfactory using current methods. Recent advances in basic research on both in vitro and in vivo models have suggested that TSH analogs could be used for diagnosis and treatment of some of the thyroid diseases. The advent of high-throughput screening methods has resulted in a group of TSH analogs called small molecules, which have the potential to be developed as promising drugs. Small molecules are low molecular weight compounds with agonist, antagonist and, in some cases, inverse agonist activity on TSHR. This short review will focus on current advances in development of TSH analogs and their potential clinical applications. Rapid advances in this field may lead to the conduct of clinical trials of small molecules related to TSHR for the management of Graves' disease, thyroid cancer, and thyroid-related osteoporosis in the coming years. Copyright © 2012 SEEN. Published by Elsevier Espana. All rights reserved.

  3. G protein coupled receptors as targets for next generation pesticides.

    Science.gov (United States)

    Audsley, Neil; Down, Rachel E

    2015-12-01

    There is an on-going need for the discovery and development of new pesticides due to the loss of existing products through the continuing development of resistance, the desire for products with more favourable environmental and toxicological profiles and the need to implement the principles of integrated pest management. Insect G protein coupled receptors (GPCRs) have important roles in modulating biology, physiology and behaviour, including reproduction, osmoregulation, growth and development. Modifying normal receptor function by blocking or over stimulating its actions may either result in the death of a pest or disrupt its normal fitness or reproductive capacity to reduce pest populations. Hence GPCRs offer potential targets for the development of next generation pesticides providing opportunities to discover new chemistries for invertebrate pest control. Such receptors are important targets for pharmaceutical drugs, but are under-exploited by the agro-chemical industry. The octopamine receptor agonists are the only pesticides with a recognized mode of action, as described in the classification scheme developed by the Insecticide Resistance Action Committee, that act via a GPCR. The availability of sequenced insect genomes has facilitated the characterization of insect GPCRs, but the development and utilization of screening assays to identify lead compounds has been slow. Various studies using knock-down technologies or applying the native ligands and/or neuropeptide analogues to pest insects in vivo, have however demonstrated that modifying normal receptor function can have an insecticidal effect. This review presents examples of potential insect neuropeptide receptors that are potential targets for lead compound development, using case studies from three representative pest species, Tribolium castaneum, Acyrthosiphon pisum, and Drosophila suzukii. Functional analysis studies on T. castaneum suggest that GPCRs involved in growth and development (eclosion

  4. A2A-D2 receptor-receptor interaction modulates gliotransmitter release from striatal astrocyte processes.

    Science.gov (United States)

    Cervetto, Chiara; Venturini, Arianna; Passalacqua, Mario; Guidolin, Diego; Genedani, Susanna; Fuxe, Kjell; Borroto-Esquela, Dasiel O; Cortelli, Pietro; Woods, Amina; Maura, Guido; Marcoli, Manuela; Agnati, Luigi F

    2017-01-01

    Evidence for striatal A2A-D2 heterodimers has led to a new perspective on molecular mechanisms involved in schizophrenia and Parkinson's disease. Despite the increasing recognition of astrocytes' participation in neuropsychiatric disease vulnerability, involvement of striatal astrocytes in A2A and D2 receptor signal transmission has never been explored. Here, we investigated the presence of D2 and A2A receptors in isolated astrocyte processes prepared from adult rat striatum by confocal imaging; the effects of receptor activation were measured on the 4-aminopyridine-evoked release of glutamate from the processes. Confocal analysis showed that A2A and D2 receptors were co-expressed on the same astrocyte processes. Evidence for A2A-D2 receptor-receptor interactions was obtained by measuring the release of the gliotransmitter glutamate: D2 receptors inhibited the glutamate release, while activation of A2A receptors, per se ineffective, abolished the effect of D2 receptor activation. The synthetic D2 peptide VLRRRRKRVN corresponding to the receptor region involved in electrostatic interaction underlying A2A-D2 heteromerization abolished the ability of the A2A receptor to antagonize the D2 receptor-mediated effect. Together, the findings are consistent with heteromerization of native striatal astrocytic A2A-D2 receptors that via allosteric receptor-receptor interactions could play a role in the control of striatal glutamatergic transmission. These new findings suggest possible new pathogenic mechanisms and/or therapeutic approaches to neuropsychiatric disorders. © 2016 International Society for Neurochemistry.

  5. Peroxisome proliferator-activated receptor alpha target genes.

    Science.gov (United States)

    Rakhshandehroo, Maryam; Knoch, Bianca; Müller, Michael; Kersten, Sander

    2010-01-01

    The peroxisome proliferator-activated receptor alpha (PPARα) is a ligand-activated transcription factor involved in the regulation of a variety of processes, ranging from inflammation and immunity to nutrient metabolism and energy homeostasis. PPARα serves as a molecular target for hypolipidemic fibrates drugs which bind the receptor with high affinity. Furthermore, PPARα binds and is activated by numerous fatty acids and fatty acid-derived compounds. PPARα governs biological processes by altering the expression of a large number of target genes. Accordingly, the specific role of PPARα is directly related to the biological function of its target genes. Here, we present an overview of the involvement of PPARα in lipid metabolism and other pathways through a detailed analysis of the different known or putative PPARα target genes. The emphasis is on gene regulation by PPARα in liver although many of the results likely apply to other organs and tissues as well.

  6. Peroxisome Proliferator-Activated Receptor Alpha Target Genes

    Directory of Open Access Journals (Sweden)

    Maryam Rakhshandehroo

    2010-01-01

    Full Text Available The peroxisome proliferator-activated receptor alpha (PPARα is a ligand-activated transcription factor involved in the regulation of a variety of processes, ranging from inflammation and immunity to nutrient metabolism and energy homeostasis. PPARα serves as a molecular target for hypolipidemic fibrates drugs which bind the receptor with high affinity. Furthermore, PPARα binds and is activated by numerous fatty acids and fatty acid-derived compounds. PPARα governs biological processes by altering the expression of a large number of target genes. Accordingly, the specific role of PPARα is directly related to the biological function of its target genes. Here, we present an overview of the involvement of PPARα in lipid metabolism and other pathways through a detailed analysis of the different known or putative PPARα target genes. The emphasis is on gene regulation by PPARα in liver although many of the results likely apply to other organs and tissues as well.

  7. Sigma-1 receptor: The novel intracellular target of neuropsychotherapeutic drugs

    Directory of Open Access Journals (Sweden)

    Teruo Hayashi

    2015-01-01

    Full Text Available Sigma-1 receptor ligands have been long expected to serve as drugs for treatment of human diseases such as neurodegenerative disorders, depression, idiopathic pain, drug abuse, and cancer. Recent research exploring the molecular function of the sigma-1 receptor started unveiling underlying mechanisms of the therapeutic activity of those ligands. Via the molecular chaperone activity, the sigma-1 receptor regulates protein folding/degradation, ER/oxidative stress, and cell survival. The chaperone activity is activated or inhibited by synthetic sigma-1 receptor ligands in an agonist-antagonist manner. Sigma-1 receptors are localized at the endoplasmic reticulum (ER membranes that are physically associated with the mitochondria (MAM: mitochondria-associated ER membrane. In specific types of neurons (e.g., those at the spinal cord, sigma-1 receptors are also clustered at ER membranes that juxtapose postsynaptic plasma membranes. Recent studies indicate that sigma-1 receptors, partly in sake of its unique subcellular localization, regulate the mitochondria function that involves bioenergetics and free radical generation. The sigma-1 receptor may thus provide an intracellular drug target that enables controlling ER stress and free radical generation under pathological conditions.

  8. Targeting Androgen Receptor Aberrations in Castration-Resistant Prostate Cancer.

    Science.gov (United States)

    Sharp, Adam; Welti, Jonathan; Blagg, Julian; de Bono, Johann S

    2016-09-01

    Androgen receptor (AR) splice variants (SV) have been implicated in the development of metastatic castration-resistant prostate cancer and resistance to AR targeting therapies, including abiraterone and enzalutamide. Agents targeting AR-SV are urgently needed to test this hypothesis and further improve the outcome of patients suffering from this lethal disease. Clin Cancer Res; 22(17); 4280-2. ©2016 AACRSee related article by Yang et al., p. 4466.

  9. Peroxisome Proliferator-Activated Receptor Alpha Target Genes

    NARCIS (Netherlands)

    Rakhshandehroo, M.; Knoch, B.; Müller, M.R.; Kersten, A.H.

    2010-01-01

    The peroxisome proliferator-activated receptor alpha (PPAR alpha) is a ligand-activated transcription factor involved in the regulation of a variety of processes, ranging from inflammation and immunity to nutrient metabolism and energy homeostasis. PPAR alpha serves as a molecular target for hypolip

  10. Peroxisome Proliferator-Activated Receptor Alpha Target Genes

    NARCIS (Netherlands)

    Rakhshandehroo, M.; Knoch, B.; Müller, M.R.; Kersten, A.H.

    2010-01-01

    The peroxisome proliferator-activated receptor alpha (PPAR alpha) is a ligand-activated transcription factor involved in the regulation of a variety of processes, ranging from inflammation and immunity to nutrient metabolism and energy homeostasis. PPAR alpha serves as a molecular target for

  11. Discoidin Domain Receptors: Potential Actors and Targets in Cancer

    Directory of Open Access Journals (Sweden)

    Hassan eRammal

    2016-03-01

    Full Text Available The extracellular matrix critically controls cancer cell behavior by inducing several signaling pathways through cell membrane receptors. Besides conferring structural properties to tissues around the tumor, the extracellular matrix is able to regulate cell proliferation, survival, migration and invasion. Among these receptors, the integrins family constitutes a major class of receptors that mediate cell interactions with extracellular matrix components.Twenty years ago, a new class of extracellular matrix receptors has been discovered. These tyrosine kinase receptors are the two discoidin domain receptors DDR1 and DDR2. DDR1 was first identified in the Dictyostelium discoideum and was shown to mediate cell aggregation. DDR2 shares highly conserved sequences with DDR1. Both receptors are activated upon binding to collagen, one of the most abundant proteins in extracellular matrix. While DDR2 can only be activated by fibrillar collagen, particularly types I and III, DDR1 is mostly activated by type I and IV collagens. In contrast with classical growth factor tyrosine kinase receptors which display a rapid and transient activation, DDR1 and DDR2 are unique in that they exhibit delayed and sustained receptor phosphorylation upon binding to collagen. Recent studies have reported differential expression and mutations of DDR1 and DDR2 in several cancer types and indicate clearly that these receptors have to be taken into account as new players in the different aspects of tumor progression, from non-malignant to highly malignant and invasive stages. This review will discuss the current knowledge on the role DDR1 and DDR2 in malignant transformation, cell proliferation, epithelial to mesenchymal transition, migratory and invasive processes, and finally the modulation of the response to chemotherapy. These new insights suggest that DDR1 and DDR2 are new potential targets in cancer therapy.

  12. Peptide Receptor Targeting in Cancer: The Somatostatin Paradigm

    Directory of Open Access Journals (Sweden)

    Federica Barbieri

    2013-01-01

    Full Text Available Peptide receptors involved in pathophysiological processes represent promising therapeutic targets. Neuropeptide somatostatin (SST is produced by specialized cells in a large number of human organs and tissues. SST primarily acts as inhibitor of endocrine and exocrine secretion via the activation of five G-protein-coupled receptors, named sst1–5, while in central nervous system, SST acts as a neurotransmitter/neuromodulator, regulating locomotory and cognitive functions. Critical points of SST/SST receptor biology, such as signaling pathways of individual receptor subtypes, homo- and heterodimerization, trafficking, and cross-talk with growth factor receptors, have been extensively studied, although functions associated with several pathological conditions, including cancer, are still not completely unraveled. Importantly, SST exerts antiproliferative and antiangiogenic effects on cancer cells in vitro, and on experimental tumors in vivo. Moreover, SST agonists are clinically effective as antitumor agents for pituitary adenomas and gastro-pancreatic neuroendocrine tumors. However, SST receptors being expressed by tumor cells of various tumor histotypes, their pharmacological use is potentially extendible to other cancer types, although to date no significant results have been obtained. In this paper the most recent findings on the expression and functional roles of SST and SST receptors in tumor cells are discussed.

  13. Targeting Insulin Receptor with a Novel Internalizing Aptamer

    Directory of Open Access Journals (Sweden)

    Margherita Iaboni

    2016-01-01

    Full Text Available Nucleic acid-based aptamers are emerging as therapeutic antagonists of disease-associated proteins such as receptor tyrosine kinases. They are selected by an in vitro combinatorial chemistry approach, named Systematic Evolution of Ligands by Exponential enrichment (SELEX, and thanks to their small size and unique chemical characteristics, they possess several advantages over antibodies as diagnostics and therapeutics. In addition, aptamers that rapidly internalize into target cells hold as well great potential for their in vivo use as delivery tools of secondary therapeutic agents. Here, we describe a nuclease resistant RNA aptamer, named GL56, which specifically recognizes the insulin receptor (IR. Isolated by a cell-based SELEX method that allows enrichment for internalizing aptamers, GL56 rapidly internalizes into target cells and is able to discriminate IR from the highly homologous insulin-like growth factor receptor 1. Notably, when applied to IR expressing cancer cells, the aptamer inhibits IR dependent signaling. Given the growing interest in the insulin receptor as target for cancer treatment, GL56 reveals a novel molecule with great translational potential as inhibitor and delivery tool for IR-dependent cancers.

  14. Targeting the epidermal growth factor receptor in solid tumor malignancies

    DEFF Research Database (Denmark)

    Nedergaard, Mette K; Hedegaard, Chris J; Poulsen, Hans S

    2012-01-01

    The epidermal growth factor receptor (EGFR) is over-expressed, as well as mutated, in many types of cancers. In particular, the EGFR variant type III mutant (EGFRvIII) has attracted much attention as it is frequently and exclusively found on many tumor cells, and hence both EGFR and EGFRvIII have...... been proposed as valid targets in many cancer therapy settings. Different strategies have been developed in order to either inhibit EGFR/EGFRvIII activity or to ablate EGFR/EGFRvIII-positive tumor cells. Drugs that inhibit these receptors include monoclonal antibodies (mAbs) that bind...

  15. Adenosine inhibits neutrophil vascular endothelial growth factor release and transendothelial migration via A2B receptor activation.

    LENUS (Irish Health Repository)

    Wakai, A

    2012-02-03

    The effects of adenosine on neutrophil (polymorphonuclear neutrophils; PMN)-directed changes in vascular permeability are poorly characterized. This study investigated whether adenosine modulates activated PMN vascular endothelial growth factor (vascular permeability factor; VEGF) release and transendothelial migration. PMN activated with tumour necrosis factor-alpha (TNF-alpha, 10 ng\\/mL) were incubated with adenosine and its receptor-specific analogues. Culture supernatants were assayed for VEGF. PMN transendothelial migration across human umbilical vein endothelial cell (HUVEC) monolayers was assessed in vitro. Adhesion molecule receptor expression was assessed flow cytometrically. Adenosine and some of its receptor-specific analogues dose-dependently inhibited activated PMN VEGF release. The rank order of potency was consistent with the affinity profile of human A2B receptors. The inhibitory effect of adenosine was reversed by 3,7-dimethyl-1-propargylxanthine, an A2 receptor antagonist. Adenosine (100 microM) or the A2B receptor agonist 5\\'-N-ethylcarboxamidoadenosine (NECA, 100 microM) significantly reduced PMN transendothelial migration. However, expression of activated PMN beta2 integrins and HUVEC ICAM-1 were not significantly altered by adenosine or NECA. Adenosine attenuates human PMN VEGF release and transendothelial migration via the A2B receptor. This provides a novel target for the modulation of PMN-directed vascular hyperpermeability in conditions such as the capillary leak syndrome.

  16. Identification of the platelet ADP receptor targeted by antithrombotic drugs.

    Science.gov (United States)

    Hollopeter, G; Jantzen, H M; Vincent, D; Li, G; England, L; Ramakrishnan, V; Yang, R B; Nurden, P; Nurden, A; Julius, D; Conley, P B

    2001-01-11

    Platelets have a crucial role in the maintenance of normal haemostasis, and perturbations of this system can lead to pathological thrombus formation and vascular occlusion, resulting in stroke, myocardial infarction and unstable angina. ADP released from damaged vessels and red blood cells induces platelet aggregation through activation of the integrin GPIIb-IIIa and subsequent binding of fibrinogen. ADP is also secreted from platelets on activation, providing positive feedback that potentiates the actions of many platelet activators. ADP mediates platelet aggregation through its action on two G-protein-coupled receptor subtypes. The P2Y1 receptor couples to Gq and mobilizes intracellular calcium ions to mediate platelet shape change and aggregation. The second ADP receptor required for aggregation (variously called P2Y(ADP), P2Y(AC), P2Ycyc or P2T(AC)) is coupled to the inhibition of adenylyl cyclase through Gi. The molecular identity of the Gi-linked receptor is still elusive, even though it is the target of efficacious antithrombotic agents, such as ticlopidine and clopidogrel and AR-C66096 (ref. 9). Here we describe the cloning of this receptor, designated P2Y12, and provide evidence that a patient with a bleeding disorder has a defect in this gene. Cloning of the P2Y12 receptor should facilitate the development of better antiplatelet agents to treat cardiovascular diseases.

  17. Asialoglycoprotein receptor mediated hepatocyte targeting - strategies and applications.

    Science.gov (United States)

    D'Souza, Anisha A; Devarajan, Padma V

    2015-04-10

    Hepatocyte resident afflictions continue to affect the human population unabated. The asialoglycoprotein receptor (ASGPR) is primarily expressed on hepatocytes and minimally on extra-hepatic cells. This makes it specifically attractive for receptor-mediated drug delivery with minimum concerns of toxicity. ASGPR facilitates internalization by clathrin-mediated endocytosis and exhibits high affinity for carbohydrates specifically galactose, N-acetylgalactosamine and glucose. Isomeric forms of sugar, galactose density and branching, spatial geometry and galactose linkages are key factors influencing ligand-receptor binding. Popular ligands for ASGPR mediated targeting are carbohydrate polymers, arabinogalactan and pullulan. Other ligands include galactose-bearing glycoproteins, glycopeptides and galactose modified polymers and lipids. Drug-ligand conjugates provide a viable strategy; nevertheless ligand-anchored nanocarriers provide an attractive option for ASGPR targeted delivery and are widely explored. The present review details various ligands and nanocarriers exploited for ASGPR mediated delivery of drugs to hepatocytes. Nanocarrier properties affecting ASGPR mediated uptake are discussed at length. The review also highlights the clinical relevance of ASGPR mediated targeting and applications in diagnostics. ASGPR mediated hepatocyte targeting provides great promise for improved therapy of hepatic afflictions.

  18. The Major Prognostic Features of Nuclear Receptor NR5A2 in Infiltrating Ductal Breast Carcinomas

    Directory of Open Access Journals (Sweden)

    Li-Yun Chang

    2015-01-01

    Full Text Available Background. Gene expression profiles of 181 breast cancer samples were analyzed to identify prognostic features of nuclear receptors NR5A1 and NR5A2 based upon their associated transcriptional networks. Methods. A supervised network analysis approach was used to build the NR5A-mediated transcriptional regulatory network. Other bioinformatic tools and statistical methods were utilized to confirm and extend results from the network analysis methodology. Results. NR5A2 expression is a negative factor in breast cancer prognosis in both ER(− and ER(−/ER(+ mixed cohorts. The clinical and cohort significance of NR5A2-mediated transcriptional activities indicates that it may have a significant role in attenuating grade development and cancer related signal transduction pathways. NR5A2 signature that conditions poor prognosis was identified based upon results from 15 distinct probes. Alternatively, the expression of NR5A1 predicts favorable prognosis when concurrent NR5A2 expression is low. A favorable signature of eight transcription factors mediated by NR5A1 was also identified. Conclusions. Correlation of poor prognosis and NR5A2 activity is identified by NR5A2-mediated 15-gene signature. NR5A2 may be a potential drug target for treating a subset of breast cancer tumors across breast cancer subtypes, especially ER(− breast tumors. The favorable prognostic feature of NR5A1 is predicted by NR5A1-mediated 8-gene signature.

  19. Receptors and Channels Targeted by Synthetic Cannabinoid Receptor Agonists and Antagonists

    OpenAIRE

    Pertwee, R. G.

    2010-01-01

    It is widely accepted that non-endogenous compounds that target CB1 and/or CB2 receptors possess therapeutic potential for the clinical management of an ever growing number of disorders. Just a few of these disorders are already treated with Δ9-tetrahydrocannabinol or nabilone, both CB1/CB2 receptor agonists, and there is now considerable interest in expanding the clinical applications of such agonists and also in exploiting CB2-selective agonists, peripherally restricted CB1/CB2 receptor ago...

  20. Targeting Toll-Like Receptors for Treatment of SLE

    Directory of Open Access Journals (Sweden)

    Christopher G. Horton

    2010-01-01

    Full Text Available Toll-like receptors (TLRs are important innate immune receptors for the identification and clearance of invading pathogens. Twelve TLRs that recognize various conserved components of microorganisms are currently known. Among these, the endosomal TLRs 3, 7/8, and 9 recognize dsRNA, ssRNA, and CpG DNA, respectively. Nucleic acid-sensing TLRs, TLR 7 in particular, have been implicated in systemic lupus erythematosus (SLE and are thought to exacerbate disease pathology. Activation of these TLRs results in the production of inflammatory cytokines and type I interferon. Genome-wide association studies, single nucleotide polymorphism analyses as well as experimental mouse models have provided evidence of TLR signaling involvement in SLE and other autoimmune diseases. Since activation of these receptor pathways promotes autoimmune phenotypes, inhibitory drugs that target these pathways constitute important new therapeutic strategies for the treatment of systemic autoimmunity.

  1. Structural comparison of phospholipase-A2-binding regions in phospholipase-A2 receptors from various mammals.

    Science.gov (United States)

    Higashino, K; Ishizaki, J; Kishino, J; Ohara, O; Arita, H

    1994-10-01

    We determined the nucleotide sequence of a mouse cDNA encoding the receptor for pancreatic group I phospholipase A2 (PLA2-I). Interspecies structural comparison of the mouse receptor with bovine PLA2-I receptor, whose structure had been clarified, revealed that the fourth carbohydrate-recognition domain (CRD)-like domain (CRD-like 4) was the most conserved among the domains in the PLA2-I receptor, suggesting the functional importance of CRD-like 4. A transient expression experiment with a truncated form of the receptor consisting of three CRD-like domains, from the third to the fifth, demonstrated that the PLA2-I-binding site of the receptor is constituted from these three CRD-like domains, supporting the functional indispensability of CRD-like 4 in the receptor. Since the PLA2-I-binding region was thus assigned to be CRD-like domains 3-5, we further analyzed the structures of the PLA2-I-binding regions in the PLA2-I receptors from the rat, rabbit and human. Furthermore, the obtained PLA2-I receptor cDNA fragments from these animals made it possible to examine the tissue expression patterns of this receptor in various mammals. The results, together with the results of the genomic structural analysis of this gene, indicated that a PLA2 receptor recently characterized by Lambeau et al. [Lambeau, G., Ancian, P., Barhanin, J. & Lazdunski, M. (1994) J. Biol. Chem. 269, 1575-1578] is a rabbit counterpart of the PLA2-I receptor although these two PLA2 receptors have distinctive PLA2-binding specificities.

  2. Prostanoid receptor EP2 as a therapeutic target.

    Science.gov (United States)

    Ganesh, Thota

    2014-06-12

    Cycoloxygenase-2 (COX-2) induction is prevalent in a variety of (brain and peripheral) injury models where COX-2 levels correlate with disease progression. Thus, COX-2 has been widely explored for anti-inflammatory therapy with COX-2 inhibitors, which proved to be effective in reducing the pain and inflammation in patients with arthritis and menstrual cramps, but they have not provided any benefit to patients with chronic inflammatory neurodegenerative disease. Recently, two COX-2 drugs, rofecoxib and valdecoxib, were withdrawn from the United States market due to cardiovascular side effects. Thus, future anti-inflammatory therapy could be targeted through a specific prostanoid receptor downstream of COX-2. The PGE2 receptor EP2 is emerging as a pro-inflammatory target in a variety of CNS and peripheral diseases. Here we highlight the latest developments on the role of EP2 in diseases, mechanism of activation, and small molecule discovery targeted either to enhance or to block the function of this receptor.

  3. Endothelin receptors as novel targets in tumor therapy

    Directory of Open Access Journals (Sweden)

    Bagnato Anna

    2004-05-01

    Full Text Available Abstract The endotelin (ET axis, that includes ET-1, ET-2, ET-3, and the ET receptors, ETA and ETB, plays an important physiological role, as modulator of vasomotor tone, tissue differentiation and development, cell proliferation, and hormone production. Recently, investigations into the role of the ET axis in mitogenesis, apoptosis inhibition, invasiveness, angiogenesis and bone remodeling have provided evidence of the importance of the ET-1 axis in cancer. Data suggest that ET-1 participates in the growth and progression of a variety of tumors such as prostatic, ovarian, renal, pulmonary, colorectal, cervical, breast carcinoma, Kaposi's sarcoma, brain tumors, melanoma, and bone metastases. ET-1 receptor antagonists beside providing ideal tools for dissecting the ET axis at molecular level have demonstrated their potential in developing novel therapeutic opportunity. The major relevance of ETA receptor in tumor development has led to an extensive search of highly selective antagonists. Atrasentan, one of such antagonists, is orally bioavailable, has suitable pharmacokinetic and toxicity profiles for clinical use. Preliminary data from clinical trials investigating atrasentan in patients with prostate cancer are encouraging. This large body of evidence demonstrates the antitumor activity of endothelin receptor antagonists and provides a rationale for the clinical evaluation of these molecules alone and in combination with cytotoxic drugs or molecular inhibitors leading to a new generation of anticancer therapies targeting endothelin receptors.

  4. Identification of potential glucocorticoid receptor therapeutic targets in multiple myeloma.

    Science.gov (United States)

    Thomas, Alexandra L; Coarfa, Cristian; Qian, Jun; Wilkerson, Joseph J; Rajapakshe, Kimal; Krett, Nancy L; Gunaratne, Preethi H; Rosen, Steven T

    2015-01-01

    Glucocorticoids (GC) are a cornerstone of combination therapies for multiple myeloma. However, patients ultimately develop resistance to GCs frequently based on decreased glucocorticoid receptor (GR) expression. An understanding of the direct targets of GC actions, which induce cell death, is expected to culminate in potential therapeutic strategies for inducing cell death by regulating downstream targets in the absence of a functional GR. The specific goal of our research is to identify primary GR targets that contribute to GC-induced cell death, with the ultimate goal of developing novel therapeutics around these targets that can be used to overcome resistance to GCs in the absence of GR. Using the MM.1S glucocorticoid-sensitive human myeloma cell line, we began with the broad platform of gene expression profiling to identify glucocorticoid-regulated genes further refined by combination treatment with phosphatidylinositol-3'-kinase inhibition (PI3Ki). To further refine the search to distinguish direct and indirect targets of GR that respond to the combination GC and PI3Ki treatment of MM.1S cells, we integrated 1) gene expression profiles of combination GC treatment with PI3Ki, which induces synergistic cell death; 2) negative correlation between genes inhibited by combination treatment in MM.1S cells and genes over-expressed in myeloma patients to establish clinical relevance and 3) GR chromatin immunoprecipitation with massively parallel sequencing (ChIP-Seq) in myeloma cells to identify global chromatin binding for the glucocorticoid receptor (GR). Using established bioinformatics platforms, we have integrated these data sets to identify a subset of candidate genes that may form the basis for a comprehensive picture of glucocorticoid actions in multiple myeloma. As a proof of principle, we have verified two targets, namely RRM2 and BCL2L1, as primary functional targets of GR involved in GC-induced cell death.

  5. Eph family receptors and ligands in vascular cell targeting and assembly.

    Science.gov (United States)

    Stein, E; Schoecklmann, H; Daniel, T O

    1997-11-01

    Members of the Eph family of receptor tyrosine kinases determine neural cell aggregation and targeting behavior, functions that are also critical in vascular assembly and remodeling. Among this class of diverse receptors, EphA2 (Eck) and EphB1 (ELK) represent prototypes for two receptor subfamilies distinguished by high-affinity interaction with either glycerophosphatidylinositol (GPI)-linked or transmembrane ligands, respectively. EphA2 participates in angiogenic responses to tumor necrosis factor (TNF) through an autocrine loop affecting endothelial cell migration. EphB1 and its ligand Ephrin-B1 (LERK-2) are important determinants of assembly of endothelial cells from the microvasculature of the kidney, where both are expressed in endothelial progenitors and in glomerular microvascular endothelial cells. Ephrin-B1 activation of EphB1 promotes assembly of these cells into capillary-like structures. Interaction trap approaches have identified downstream signaling proteins that complex with ligand-activated EphA2 or EphB1, including nonreceptor tyrosine kinases and SH2 domain-containing adapter proteins. The Grb 10 adapter is one of a subset that binds activated EphB1, but not EphA2, defining distinct signaling mechanisms for these related endothelial receptors. On the basis of observations in vascular endothelial cells and recent results defining Eph receptor and ligand roles in neural cell targeting, we propose that these receptors direct cell-cell recognition events that are critical in vasculogenesis and angiogenesis. (Trends Cardiovasc Med 1997;7:329-334). © 1997, Elsevier Science Inc.

  6. Metabotropic glutamate receptors and interacting proteins: evolving drug targets.

    Science.gov (United States)

    Enz, Ralf

    2012-01-01

    The correct targeting, localization, regulation and signaling of metabotropic glutamate receptors (mGluRs) represent major mechanisms underlying the complex function of neuronal networks. These tasks are accomplished by the formation of synaptic signal complexes that integrate functionally related proteins such as neurotransmitter receptors, enzymes and scaffold proteins. By these means, proteins interacting with mGluRs are important regulators of glutamatergic neurotransmission. Most described mGluR interaction partners bind to the intracellular C-termini of the receptors. These domains are extensively spliced and phosphorylated, resulting in a high variability of binding surfaces offered to interacting proteins. Malfunction of mGluRs and associated proteins are linked to neurodegenerative and neuropsychiatric disorders including addiction, depression, epilepsy, schizophrenia, Alzheimer's, Huntington's and Parkinson's disease. MGluR associated signal complexes are dynamic structures that assemble and disassemble in response to the neuronal fate. This, in principle, allows therapeutic intervention, defining mGluRs and interacting proteins as promising drug targets. In the last years, several studies elucidated the geometry of mGluRs in contact with regulatory proteins, providing a solid fundament for the development of new therapeutic strategies. Here, I will give an overview of human disorders directly associated with mGluR malfunction, provide an up-to-date summary of mGluR interacting proteins and highlight recently described structures of mGluR domains in contact with binding partners.

  7. Toll-like receptors as therapeutic targets in cystic fibrosis.

    LENUS (Irish Health Repository)

    Greene, Catherine M

    2008-12-01

    Background: Toll-like receptors (TLRs) are pattern recognition receptors that act as a first-line of defence in the innate immune response by recognising and responding to conserved molecular patterns in microbial factors and endogenous danger signals. Cystic fibrosis (CF)-affected airways represent a milieu potentially rich in TLR agonists and the chronic inflammatory phenotype evident in CF airway epithelial cells is probably due in large part to activation of TLRs. Objective\\/methods: To examine the prospects of developing novel therapies for CF by targeting TLRs. We outline the expression and function of TLRs and explore the therapeutic potential of naturally-occurring and synthetic TLR inhibitors for CF. Results\\/conclusion: Modulation of TLRs has therapeutic potential for the inflammatory lung manifestations of CF.

  8. The PACAP receptor: a novel target for migraine treatment

    DEFF Research Database (Denmark)

    Schytz, Henrik W; Olesen, Jes; Ashina, Messoud

    2010-01-01

    in sensory trigeminal neurons and may modulate nociception at different levels of the nervous system. Human experimental studies have shown that PACAP-38 infusion induces marked dilatation of extracerebral vessels and delayed migraine-like attacks in migraine patients. PACAP selectively activates the PAC(1......The origin of migraine pain has not yet been clarified, but accumulating data point to neuropeptides present in the perivascular space of cranial vessels as important mediators of nociceptive input during migraine attacks. Pituitary adenylate cyclase-activating polypeptide (PACAP) is present......) receptor, which suggests a possible signaling pathway implicated in migraine pain. This review summarizes the current evidence supporting the involvement of PACAP in migraine pathophysiology and the PAC(1) receptor as a possible novel target for migraine treatment....

  9. The PACAP receptor: a novel target for migraine treatment

    DEFF Research Database (Denmark)

    Schytz, Henrik W; Olesen, Jes; Ashina, Messoud

    2010-01-01

    ) receptor, which suggests a possible signaling pathway implicated in migraine pain. This review summarizes the current evidence supporting the involvement of PACAP in migraine pathophysiology and the PAC(1) receptor as a possible novel target for migraine treatment.......The origin of migraine pain has not yet been clarified, but accumulating data point to neuropeptides present in the perivascular space of cranial vessels as important mediators of nociceptive input during migraine attacks. Pituitary adenylate cyclase-activating polypeptide (PACAP) is present...... in sensory trigeminal neurons and may modulate nociception at different levels of the nervous system. Human experimental studies have shown that PACAP-38 infusion induces marked dilatation of extracerebral vessels and delayed migraine-like attacks in migraine patients. PACAP selectively activates the PAC(1...

  10. The glucocorticoid receptor: a revisited target for toxins.

    Science.gov (United States)

    Marketon, Jeanette I Webster; Sternberg, Esther M

    2010-06-01

    The hypothalamic-pituitary-adrenal (HPA) axis activation and glucocorticoid responses are critical for survival from a number of bacterial, viral and toxic insults, demonstrated by the fact that removal of the HPA axis or GR blockade enhances mortality rates. Replacement with synthetic glucocorticoids reverses these effects by providing protection against lethal effects. Glucocorticoid resistance/insensitivity is a common problem in the treatment of many diseases. Much research has focused on the molecular mechanism behind this resistance, but an area that has been neglected is the role of infectious agents and toxins. We have recently shown that the anthrax lethal toxin is able to repress glucocorticoid receptor function. Data suggesting that the glucocorticoid receptor may be a target for a variety of toxins is reviewed here. These studies have important implications for glucocorticoid therapy.

  11. Targeting proteasome ubiquitin receptor Rpn13 in multiple myeloma.

    Science.gov (United States)

    Song, Y; Ray, A; Li, S; Das, D S; Tai, Y T; Carrasco, R D; Chauhan, D; Anderson, K C

    2016-09-01

    Proteasome inhibitor bortezomib is an effective therapy for relapsed and newly diagnosed multiple myeloma (MM); however, dose-limiting toxicities and the development of resistance can limit its long-term utility. Recent research has focused on targeting ubiquitin receptors upstream of 20S proteasome, with the aim of generating less toxic therapies. Here we show that 19S proteasome-associated ubiquitin receptor Rpn13 is more highly expressed in MM cells than in normal plasma cells. Rpn13-siRNA (small interfering RNA) decreases MM cell viability. A novel agent RA190 targets Rpn13 and inhibits proteasome function, without blocking the proteasome activity or the 19S deubiquitylating activity. CRISPR/Cas9 Rpn13-knockout demonstrates that RA190-induced activity is dependent on Rpn13. RA190 decreases viability in MM cell lines and patient MM cells, inhibits proliferation of MM cells even in the presence of bone marrow stroma and overcomes bortezomib resistance. Anti-MM activity of RA190 is associated with induction of caspase-dependent apoptosis and unfolded protein response-related apoptosis. MM xenograft model studies show that RA190 is well tolerated, inhibits tumor growth and prolongs survival. Combining RA190 with bortezomib, lenalidomide or pomalidomide induces synergistic anti-MM activity. Our preclinical data validates targeting Rpn13 to overcome bortezomib resistance, and provides the framework for clinical evaluation of Rpn13 inhibitors, alone or in combination, to improve patient outcome in MM.

  12. Role of Microglia Adenosine A2A Receptors in Retinal and Brain Neurodegenerative Diseases

    Directory of Open Access Journals (Sweden)

    Ana R. Santiago

    2014-01-01

    Full Text Available Neuroinflammation mediated by microglial cells in the brain has been commonly associated with neurodegenerative diseases. Whether this microglia-mediated neuroinflammation is cause or consequence of neurodegeneration is still a matter of controversy. However, it is unequivocal that chronic neuroinflammation plays a role in disease progression and halting that process represents a potential therapeutic strategy. The neuromodulator adenosine emerges as a promising targeting candidate based on its ability to regulate microglial proliferation, chemotaxis, and reactivity through the activation of its G protein coupled A2A receptor (A2AR. This is in striking agreement with the ability of A2AR blockade to control several brain diseases. Retinal degenerative diseases have been also associated with microglia-mediated neuroinflammation, but the role of A2AR has been scarcely explored. This review aims to compare inflammatory features of Parkinson’s and Alzheimer’s diseases with glaucoma and diabetic retinopathy, discussing the therapeutic potential of A2AR in these degenerative conditions.

  13. Current drug treatments targeting dopamine D3 receptor.

    Science.gov (United States)

    Leggio, Gian Marco; Bucolo, Claudio; Platania, Chiara Bianca Maria; Salomone, Salvatore; Drago, Filippo

    2016-09-01

    Dopamine receptors (DR) have been extensively studied, but only in recent years they became object of investigation to elucidate the specific role of different subtypes (D1R, D2R, D3R, D4R, D5R) in neural transmission and circuitry. D1-like receptors (D1R and D5R) and D2-like receptors (D2R, D2R and D4R) differ in signal transduction, binding profile, localization in the central nervous system and physiological effects. D3R is involved in a number of pathological conditions, including schizophrenia, Parkinson's disease, addiction, anxiety, depression and glaucoma. Development of selective D3R ligands has been so far challenging, due to the high sequence identity and homology shared by D2R and D3R. As a consequence, despite a rational design of selective DR ligands has been carried out, none of currently available medicines selectively target a given D2-like receptor subtype. The availability of the D3R ligand [(11)C]-(+)-PHNO for positron emission tomography studies in animal models as well as in humans, allows researchers to estimate the expression of D3R in vivo; displacement of [(11)C]-(+)-PHNO binding by concurrent drug treatments is used to estimate the in vivo occupancy of D3R. Here we provide an overview of studies indicating D3R as a target for pharmacological therapy, and a review of market approved drugs endowed with significant affinity at D3R that are used to treat disorders where D3R plays a relevant role.

  14. Yersinia pestis targets neutrophils via complement receptor 3

    Science.gov (United States)

    Merritt, Peter M.; Nero, Thomas; Bohman, Lesley; Felek, Suleyman; Krukonis, Eric S.; Marketon, Melanie M.

    2015-01-01

    Yersinia species display a tropism for lymphoid tissues during infection, and the bacteria select innate immune cells for delivery of cytotoxic effectors by the type III secretion system. Yet the mechanism for target cell selection remains a mystery. Here we investigate the interaction of Yersinia pestis with murine splenocytes to identify factors that participate in the targeting process. We find that interactions with primary immune cells rely on multiple factors. First, the bacterial adhesin Ail is required for efficient targeting of neutrophils in vivo. However, Ail does not appear to directly mediate binding to a specific cell type. Instead, we find that host serum factors direct Y. pestis to specific innate immune cells, particularly neutrophils. Importantly, specificity towards neutrophils was increased in the absence of bacterial adhesins due to reduced targeting of other cell types, but this phenotype was only visible in the presence of mouse serum. Addition of antibodies against complement receptor 3 and CD14 blocked target cell selection, suggesting that a combination of host factors participate in steering bacteria toward neutrophils during plague infection. PMID:25359083

  15. The NR4A nuclear receptors as potential targets for anti-aging interventions.

    Science.gov (United States)

    Paillasse, Michael R; de Medina, Philippe

    2015-02-01

    The development of innovative anti-aging strategy is urgently needed to promote healthy aging and overcome the occurrence of age-related diseases such as cancer, diabetes, cardiovascular and neurodegenerative diseases. Genomic instability, deregulated nutrient sensing and mitochondrial dysfunction are established hallmark of aging. Interestingly, the orphan nuclear receptors NR4A subfamily (NR4A1, NR4A2 and NR4A3) are nutrient sensors that trigger mitochondria biogenesis and improve intrinsic mitochondrial function. In addition, NR4A receptors are components of DNA repair machinery and promote DNA repair. Members of the NR4A subfamily should also be involved in anti-aging properties of hormesis since these receptors are induced by various form of cellular stress and stimulate protective cells response such as anti-oxidative activity and DNA repair. Previous studies reported that NR4A nuclear receptors subfamily is potential therapeutic targets for the treatment of age related disorders (e.g. metabolic syndromes, diabetes and neurodegenerative diseases). Consequently, we propose that targeting NR4A receptors might constitute a new approach to delay aging and the onset of diseases affecting our aging population.

  16. Prospects in folate receptor-targeted radionuclide therapy

    Directory of Open Access Journals (Sweden)

    Cristina eMüller

    2013-09-01

    Full Text Available Targeted radionuclide therapy is based on systemic application of particle-emitting radiopharmaceuticals which are directed towards a specific tumor-associated target. Accumulation of the radiopharmaceutical in targeted cancer cells results in high doses of absorbed radiation energy whereas toxicity to non-targeted healthy tissue is limited. This strategy has found widespread application in the palliative treatment of neuroendocrine tumors using somatostatin-based radiopeptides. The folate receptor (FR has been identified as a target associated with a variety of frequent tumor types (e.g. ovarian, lung, brain, renal and colorectal cancer. In healthy organs and tissue FR-expression is restricted to only a few sites such as for instance the kidneys. This demonstrates why FR-targeting is an attractive strategy for the development of new therapy concepts. Due to its high FR-binding affinity (KD < 10-9 M the vitamin folic acid has emerged as an almost ideal targeting agent. Therefore, a variety of folic acid radioconjugates for nuclear imaging have been developed. However, in spite of the large number of cancer patients who could benefit of a folate-based radionuclide therapy, a therapeutic concept with folate radioconjugates has not yet been envisaged for clinical application. The reason is the generally high accumulation of folate radioconjugates in the kidneys where emission of particle-radiation may result in damage to the renal tissue. Therefore, the design of more sophisticated folate radioconjugates providing improved tissue distribution profiles are needed.This review article summarizes recent developments with regard to a therapeutic application of folate radioconjugates. A new construct of a folate radioconjugate and an application protocol which makes use of a pharmacological interaction allowed the first preclinical therapy experiments with radiofolates. These results raise hope for future application of such new concepts also in the

  17. Expression, Purification and Crystallisation of the Adenosine A2A Receptor Bound to an Engineered Mini G Protein.

    Science.gov (United States)

    Carpenter, Byron; Tate, Christopher G

    2017-04-20

    G protein-coupled receptors (GPCRs) promote cytoplasmic signalling by activating heterotrimeric G proteins in response to extracellular stimuli such as light, hormones and nucleosides. Structure determination of GPCR-G protein complexes is central to understanding the precise mechanism of signal transduction. However, these complexes are challenging targets for structural studies due to their conformationally dynamic and inherently transient nature. We recently developed an engineered G protein, mini-Gs, which addressed these problems and allowed the formation of a stable GPCR-G protein complex. Mini-Gs facilitated the structure determination of the human adenosine A2A receptor (A2AR) in its G protein-bound conformation at 3.4 Å resolution. Here, we describe a step by step protocol for the expression and purification of A2AR, and crystallisation of the A2AR-mini-Gs complex.

  18. Targeting ryanodine receptors for anti-arrhythmic therapy

    Institute of Scientific and Technical Information of China (English)

    Mark D McCAULEY; Xander H T WEHRENS

    2011-01-01

    Antiarrhythmic drugs are a group of pharmaceuticals that suppress or prevent abnormal heart rhythms, which are often associated with substantial morbidity and mortality. Current antiarrhythmic drugs that typically target plasma membrane ion channels have limited clinical success and in some cases have been described as being pro-arrhythmic. However, recent studies suggest that pathological release of calcium (Ca2+) from the sarcoplasmic reticulum via cardiac ryanodine receptors (RyR2) could represent a promising target for antiarrhythmic therapy. Diastolic SR Ca2+ release has been linked to arrhythmogenesis in both the inherited arrhythmia synSeveral classes of pharmaceuticals have been shown to reduce abnormal RyR2 activity and may confer protection against triggered arrhythmias through reduction of SR Ca2+ leak. In this review, we will evaluate the current pharmacological methods for stabilizing RyR2 and suggest treatment modalities based on current evidence of molecular mechanisms.

  19. Antiphospholipase A2 Receptor Autoantibodies: A Step Forward in the Management of Primary Membranous Nephropathy

    Directory of Open Access Journals (Sweden)

    Bogdan Obrisca

    2015-01-01

    Full Text Available Since the identification of PLA2R (M-type phospholipase A2 receptor as the first human antigenic target in primary membranous nephropathy (MN, perpetual progress has been made in understanding the pathogenesis of this disease. Accumulating clinical data support a pathogenic role for the anti-PLA2R antibodies (PLA2R ABs, but confirmation in an animal model is still lacking. However, PLA2R ABs were related to disease activity and outcome, as well as to response therapy. Accordingly, PLA2R ABs assay seems to be promising tool not only to diagnose MN but also to predict the course of the disease and could open the way to personalize therapy. Nevertheless, validation of a universal assay with high precision and definition of cut-off levels, followed by larger studies with a prolonged follow-up period, are needed to confirm these prospects.

  20. Antiphospholipase A2 Receptor Autoantibodies: A Step Forward in the Management of Primary Membranous Nephropathy.

    Science.gov (United States)

    Obrisca, Bogdan; Ismail, Gener; Jurubita, Roxana; Baston, Catalin; Andronesi, Andreea; Mircescu, Gabriel

    2015-01-01

    Since the identification of PLA2R (M-type phospholipase A2 receptor) as the first human antigenic target in primary membranous nephropathy (MN), perpetual progress has been made in understanding the pathogenesis of this disease. Accumulating clinical data support a pathogenic role for the anti-PLA2R antibodies (PLA2R ABs), but confirmation in an animal model is still lacking. However, PLA2R ABs were related to disease activity and outcome, as well as to response therapy. Accordingly, PLA2R ABs assay seems to be promising tool not only to diagnose MN but also to predict the course of the disease and could open the way to personalize therapy. Nevertheless, validation of a universal assay with high precision and definition of cut-off levels, followed by larger studies with a prolonged follow-up period, are needed to confirm these prospects.

  1. AT2 Receptors: Potential Therapeutic Targets for Hypertension.

    Science.gov (United States)

    Carey, Robert M

    2017-04-01

    The renin-angiotensin system (RAS) is arguably the most important and best studied hormonal system in the control of blood pressure (BP) and the pathogenesis of hypertension. The RAS features its main effector angiotensin II (Ang II) acting via its 2 major receptors, angiotensin type-1(AT1R) and type-2 (AT2R). In general, AT2Rs oppose the detrimental actions of Ang II via AT1Rs. AT2R activation induces vasodilation and natriuresis, but its effects to lower BP in hypertension have not been as clear as anticipated. Recent studies, however, have demonstrated that acute and chronic AT2R stimulation can induce natriuresis and lower BP in the Ang II infusion model of experimental hypertension. AT2R activation induces receptor recruitment from intracellular sites to the apical plasma membranes of renal proximal tubule cells via a bradykinin, nitric oxide, and cyclic guanosine 3',5' monophosphate signaling pathway that results in internalization and inactivation of sodium (Na+) transporters Na+-H+ exchanger-3 and Na+/K+ATPase. These responses do not require the presence of concurrent AT1R blockade and are effective both in the prevention and reversal of hypertension. This review will address the role of AT2Rs in the control of BP and Na+ excretion and the case for these receptors as potential therapeutic targets for hypertension in humans. © American Journal of Hypertension, Ltd 2016. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  2. Role of nuclear receptor NR4A2 in gastrointestinal inflammation and cancers

    Institute of Scientific and Technical Information of China (English)

    Yi-Fang Han; Guang-Wen Cao

    2012-01-01

    NR4A2 is a transcription factor belonging to the steroid orphan nuclear receptor superfamily.It was originally considered to be essential in the generation and maintenance of dopaminergic neurons,and associated with neurological disorders such as Parkinson's disease.Recently,NR4A2 has been found to play a critical role in some inflammatory diseases and cancer.NR4A2 can be efficiently trans-activated by some proinflammatory cytokines,such as tumor necrosis factor-α,interleukin-1β,and vascular endothelial growth factor (VEGF).The nuclear factor-κB signaling pathway serves as a principal regulator of inducible NR4A expression in immune cells.NR4A2 can trans-activate Foxp3,a hallmark specifically expressed in regulatory T (Treg) cells,and plays a critical role in the differentiation,maintenance,and function of Treg cells.NR4A2 in T lymphocytes is pivotal for Treg cell induction and suppression of aberrant induction of Th1 under physiological and pathological conditions.High density of Foxp3+ Treg cells is significantly associated with gastrointestinal inflammation,tumor immune escape,and disease progression.NR4A2 is produced at high levels in CD133+ colorectal carcinoma (CRC) cells and significantly upregulated by cyclooxygenase-2-derived prostaglandin E2 in a cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA)-dependent manner in CRC cells.The cAMP/PKA signaling pathway is the common pathway of NR4A2-related inflammation and cancer.NR4A2 trans-activates osteopontin,a direct target of the Wnt/β-catenin pathway associated with CRC invasion,metastasis,and poor prognosis.Knockdown of endogenous NR4A2 expression attenuates VEGF-induced endothelial cell proliferation,migration and in vivo angiogenesis.Taken together,NR4A2 emerges as an important nuclear factor linking gastrointestinal inflammation and cancer,especially CRC,and should serve as a candidate therapeutic target for inflammation-related gastrointestinal cancer.

  3. A novel gene delivery system targeting cells expressing VEGF receptors

    Institute of Scientific and Technical Information of China (English)

    LIJUNMIN; JINGCHULUO; 等

    1999-01-01

    Two ligand oligopeptides GV1 and GV2 were designed according to the putative binding region of VEGF to its receptors.GV1,GV2 and endosome releasing oligopeptide HA20 were conjugated with poly-L-lysine or protamine and the resulting conjugates could interact with DNA in a noncovalent bond to form a complex.Using pSV2-β-galactosidase as a reporter gene,it has been demonstrated that exogenous gene was transferred into bovine aortic arch-derived endothelial cells (ABAE) and human malignant melanoma cell lines (A375) in vitro.In vivo experiments,exogenous gene was transferred into tumor vascular endothelial cells and tumor cells of subcutaneously transplanted human colon cancer LOVO,human malignant melanoma A375 and human hepatoma graft in nude mice.This system could also target gene to intrahepatically transplanted human hepatoma injected via portal vein in nude mice.These results are correlated with the relevant receptors(flt-1,flk-1/KDR) expression on the targeted cells and tissues.

  4. MicroRNA-223 is neuroprotective by targeting glutamate receptors

    Science.gov (United States)

    Harraz, Maged M.; Eacker, Stephen M.; Wang, Xueqing; Dawson, Ted M.; Dawson, Valina L.

    2012-01-01

    Stroke is a major cause of mortality and morbidity worldwide. Extracellular glutamate accumulation leading to overstimulation of the ionotropic glutamate receptors mediates neuronal injury in stroke and in neurodegenerative disorders. Here we show that miR-223 controls the response to neuronal injury by regulating the functional expression of the glutamate receptor subunits GluR2 and NR2B in brain. Overexpression of miR-223 lowers the levels of GluR2 and NR2B by targeting 3′-UTR target sites (TSs) in GluR2 and NR2B, inhibits NMDA-induced calcium influx in hippocampal neurons, and protects the brain from neuronal cell death following transient global ischemia and excitotoxic injury. MiR-223 deficiency results in higher levels of NR2B and GluR2, enhanced NMDA-induced calcium influx, and increased miniature excitatory postsynaptic currents in hippocampal neurons. In addition, the absence of MiR-223 leads to contextual, but not cued memory deficits and increased neuronal cell death following transient global ischemia and excitotoxicity. These data identify miR-223 as a major regulator of the expression of GluR2 and NR2B, and suggest a therapeutic role for miR-223 in stroke and other excitotoxic neuronal disorders. PMID:23112146

  5. Receptor tyrosine kinases as target for anti-cancer therapy.

    Science.gov (United States)

    Brunelleschi, S; Penengo, L; Santoro, M M; Gaudino, G

    2002-01-01

    Receptor tyrosine kinases (RTKs) are cell surface transmembrane proteins responsible for intracellular signal transduction. They are expressed in several cell types and, after activation by growth factor binding, trigger a series of intracellular pathways, leading to a wide variety of cell responses (e.g., differentiation, proliferation, migration and invasion, angiogenesis, survival). Over-expression and/or structural alteration of RTKs family members are often associated to human cancers and tumor cells are known to use RTK transduction pathways to achieve tumor growth, angiogenesis and metastasis. Therefore, RTKs represent pivotal target in approaches of cancer therapy. A number of small molecules acting as RTK inhibitors have been synthesized by pharmaceutical companies and are under clinical trials, are being analyzed in animal models or have been successfully marketed. Ligand-dependent downregulation of RTKs is a critical step for modulating their activity and the adaptor Cbl has been indicated as the key protein involved in negative regulation of RTKs, such as EGF and HGF receptors. These data suggest novel potential pharmacological targets for the treatment of human malignancies associated to oncogenic activation of RTKs.

  6. In vivo adenosine A(2B) receptor desensitization in guinea-pig airway smooth muscle: implications for asthma.

    Science.gov (United States)

    Breschi, Maria Cristina; Blandizzi, Corrado; Fogli, Stefano; Martinelli, Cinzia; Adinolfi, Barbara; Calderone, Vincenzo; Camici, Marcella; Martinotti, Enrica; Nieri, Paola

    2007-12-01

    This study was aimed at characterizing the role of adenosine receptor subtypes in the contractility modulation of guinea-pig airway smooth muscle in normal and pathological settings. In vitro and in vivo experiments were performed by testing selective agonists and antagonists on isolated tracheal smooth muscle preparations and pulmonary inflation pressure, respectively, under normal conditions or following ovalbumin-induced allergic sensitization. In normal and sensitized animals, the adenosine A(2A)/A(2B) receptor agonist, NECA, evoked relaxing responses of isolated tracheal preparations precontracted with histamine, and such an effect was reversed by the adenosine A(2B) antagonist, MRS 1706, in the presence or in the absence of epithelium. The expression of mRNA coding for adenosine A(2B) receptors was demonstrated in tracheal specimens. In vitro desensitization with 100 microM NECA markedly reduced the relaxing effect of the agonist. In vivo NECA or adenosine administration to normal animals inhibited histamine-mediated bronchoconstriction, while these inhibitory effects no longer occurred in sensitized guinea-pigs. Adenosine plasma levels were significantly higher in sensitized than normal animals. In conclusion, our data demonstrate that: (i) adenosine A(2B) receptors are responsible for the relaxing effects of adenosine on guinea-pig airways; (ii) these receptors can undergo rapid adaptive changes that may affect airway smooth muscle responsiveness to adenosine; (iii) ovalbumin-induced sensitization promotes a reversible inactivation of adenosine A(2B) receptors which can be ascribed to homologous desensitization. These findings can be relevant to better understand adenosine functions in airways as well as mechanisms of action of asthma therapies targeting the adenosine system.

  7. Inhibition of nicotinic acetylcholine receptors, a novel facet in the pleiotropic activities of snake venom phospholipases A2.

    Directory of Open Access Journals (Sweden)

    Catherine A Vulfius

    Full Text Available Phospholipases A2 represent the most abundant family of snake venom proteins. They manifest an array of biological activities, which is constantly expanding. We have recently shown that a protein bitanarin, isolated from the venom of the puff adder Bitis arietans and possessing high phospholipolytic activity, interacts with different types of nicotinic acetylcholine receptors and with the acetylcholine-binding protein. To check if this property is characteristic to all venom phospholipases A2, we have studied the capability of these enzymes from other snakes to block the responses of Lymnaea stagnalis neurons to acetylcholine or cytisine and to inhibit α-bungarotoxin binding to nicotinic acetylcholine receptors and acetylcholine-binding proteins. Here we present the evidence that phospholipases A2 from venoms of vipers Vipera ursinii and V. nikolskii, cobra Naja kaouthia, and krait Bungarus fasciatus from different snake families suppress the acetylcholine- or cytisine-elicited currents in L. stagnalis neurons and compete with α-bungarotoxin for binding to muscle- and neuronal α7-types of nicotinic acetylcholine receptor, as well as to acetylcholine-binding proteins. As the phospholipase A2 content in venoms is quite high, under some conditions the activity found may contribute to the deleterious venom effects. The results obtained suggest that the ability to interact with nicotinic acetylcholine receptors may be a general property of snake venom phospholipases A2, which add a new target to the numerous activities of these enzymes.

  8. Inhibition of nicotinic acetylcholine receptors, a novel facet in the pleiotropic activities of snake venom phospholipases A2.

    Science.gov (United States)

    Vulfius, Catherine A; Kasheverov, Igor E; Starkov, Vladislav G; Osipov, Alexey V; Andreeva, Tatyana V; Filkin, Sergey Yu; Gorbacheva, Elena V; Astashev, Maxim E; Tsetlin, Victor I; Utkin, Yuri N

    2014-01-01

    Phospholipases A2 represent the most abundant family of snake venom proteins. They manifest an array of biological activities, which is constantly expanding. We have recently shown that a protein bitanarin, isolated from the venom of the puff adder Bitis arietans and possessing high phospholipolytic activity, interacts with different types of nicotinic acetylcholine receptors and with the acetylcholine-binding protein. To check if this property is characteristic to all venom phospholipases A2, we have studied the capability of these enzymes from other snakes to block the responses of Lymnaea stagnalis neurons to acetylcholine or cytisine and to inhibit α-bungarotoxin binding to nicotinic acetylcholine receptors and acetylcholine-binding proteins. Here we present the evidence that phospholipases A2 from venoms of vipers Vipera ursinii and V. nikolskii, cobra Naja kaouthia, and krait Bungarus fasciatus from different snake families suppress the acetylcholine- or cytisine-elicited currents in L. stagnalis neurons and compete with α-bungarotoxin for binding to muscle- and neuronal α7-types of nicotinic acetylcholine receptor, as well as to acetylcholine-binding proteins. As the phospholipase A2 content in venoms is quite high, under some conditions the activity found may contribute to the deleterious venom effects. The results obtained suggest that the ability to interact with nicotinic acetylcholine receptors may be a general property of snake venom phospholipases A2, which add a new target to the numerous activities of these enzymes.

  9. A2A adenosine receptor and its modulators: overview on a druggable GPCR and on structure-activity relationship analysis and binding requirements of agonists and antagonists.

    Science.gov (United States)

    Cristalli, G; Lambertucci, C; Marucci, G; Volpini, R; Dal Ben, D

    2008-01-01

    Since the discovery of the biological effects of adenosine, the development of potent and selective agonists and antagonists of adenosine receptors has been the subject of medicinal chemistry research for several decades, even if their clinical evaluation has been discontinued. Main problems include side effects due to the ubiquity of the receptors and the possibility of side effects, or to low brain penetration (in particular for the targeting of CNS diseases), short half-life of compounds, lack of effects. Furthermore, species differences in the affinity of ligands make difficult preclinical testing in animal models. Nevertheless, adenosine receptors continue to represent promising drug targets. A(2A) receptor has proved to be a promising pharmacological target for small synthetic ligands, and while A(2A) agonists are undergoing clinical trials for myocardial perfusion imaging and as anti-inflammatory agents, A(2A) antagonists represent an attractive field of research to discover new drugs for the treatment of neurodegenerative disorders, such as Parkinson's disease. Furthermore, the information coming from bioinformatics and molecular modeling studies for the A(2A) receptor has made easier the understanding of ligand-target interaction and the rational design of agonists and antagonists for this subtype. The aim of this review is to show an overview of the most significant steps and progresses in developing A(2A) adenosine receptor agonists and antagonists.

  10. Adenosine A2A receptor and ecto-5'-nucleotidase/CD73 are upregulated in hippocampal astrocytes of human patients with mesial temporal lobe epilepsy (MTLE).

    Science.gov (United States)

    Barros-Barbosa, Aurora R; Ferreirinha, Fátima; Oliveira, Ângela; Mendes, Marina; Lobo, M Graça; Santos, Agostinho; Rangel, Rui; Pelletier, Julie; Sévigny, Jean; Cordeiro, J Miguel; Correia-de-Sá, Paulo

    2016-12-01

    Refractoriness to existing medications of up to 80 % of the patients with mesial temporal lobe epilepsy (MTLE) prompts for finding new antiepileptic drug targets. The adenosine A2A receptor emerges as an interesting pharmacological target since its excitatory nature partially counteracts the dominant antiepileptic role of endogenous adenosine acting via inhibitory A1 receptors. Gain of function of the excitatory A2A receptor has been implicated in a significant number of brain pathologies commonly characterized by neuronal excitotoxicity. Here, we investigated changes in the expression and cellular localization of the A2A receptor and of the adenosine-generating enzyme, ecto-5'-nucleotidase/CD73, in the hippocampus of control individuals and MTLE human patients. Western blot analysis indicates that the A2A receptor is more abundant in the hippocampus of MTLE patients compared to control individuals. Immunoreactivity against the A2A receptor predominates in astrocytes staining positively for the glial fibrillary acidic protein (GFAP). No co-localization was observed between the A2A receptor and neuronal cell markers, like synaptotagmin 1/2 (nerve terminals) and neurofilament 200 (axon fibers). Hippocampal astrogliosis observed in MTLE patients was accompanied by a proportionate increase in A2A receptor and ecto-5'-nucleotidase/CD73 immunoreactivities. Given our data, we hypothesize that selective blockade of excessive activation of astrocytic A2A receptors and/or inhibition of surplus adenosine formation by membrane-bound ecto-5'-nucleotidase/CD73 may reduce neuronal excitability, thus providing a novel therapeutic target for drug-refractory seizures in MTLE patients.

  11. Designer interface peptide grafts target estrogen receptor alpha dimerization

    Energy Technology Data Exchange (ETDEWEB)

    Chakraborty, S. [Laboratory of Computational Biophysics & Bioengineering, Department of Physics, Tougaloo College, Tougaloo, MS 39174 (United States); Asare, B.K. [Department of Pharmacology and Toxicology, University of Buffalo, Buffalo, NY 14214 (United States); Biswas, P.K., E-mail: pbiswas@tougaloo.edu [Laboratory of Computational Biophysics & Bioengineering, Department of Physics, Tougaloo College, Tougaloo, MS 39174 (United States); Rajnarayanan, R.V., E-mail: rajendra@buffalo.edu [Department of Pharmacology and Toxicology, University of Buffalo, Buffalo, NY 14214 (United States)

    2016-09-09

    The nuclear transcription factor estrogen receptor alpha (ERα), triggered by its cognate ligand estrogen, regulates a variety of cellular signaling events. ERα is expressed in 70% of breast cancers and is a widely validated target for anti-breast cancer drug discovery. Administration of anti-estrogen to block estrogen receptor activation is still a viable anti-breast cancer treatment option but anti-estrogen resistance has been a significant bottle-neck. Dimerization of estrogen receptor is required for ER activation. Blocking ERα dimerization is therefore a complementary and alternative strategy to combat anti-estrogen resistance. Dimer interface peptide “I-box” derived from ER residues 503–518 specifically blocks ER dimerization. Recently using a comprehensive molecular simulation we studied the interaction dynamics of ERα LBDs in a homo-dimer. Based on this study, we identified three interface recognition peptide motifs LDKITDT (ERα residues 479–485), LQQQHQRLAQ (residues 497–506), and LSHIRHMSNK (residues 511–520) and reported the suitability of using LQQQHQRLAQ (ER 497–506) as a template to design inhibitors of ERα dimerization. Stability and self-aggregation of peptide based therapeutics poses a significant bottle-neck to proceed further. In this study utilizing peptide grafted to preserve their pharmacophoric recognition motif and assessed their stability and potential to block ERα mediated activity in silico and in vitro. The Grafted peptides blocked ERα mediated cell proliferation and viability of breast cancer cells but did not alter their apoptotic fate. We believe the structural clues identified in this study can be used to identify novel peptidometics and small molecules that specifically target ER dimer interface generating a new breed of anti-cancer agents. - Highlights: • Designer peptide grafts retain core molecular recognition motif during MD simulations. • Designer peptide grafts with Poly-ALA helix form stable

  12. A2BR adenosine receptor modulates sweet taste in circumvallate taste buds.

    Directory of Open Access Journals (Sweden)

    Shinji Kataoka

    Full Text Available In response to taste stimulation, taste buds release ATP, which activates ionotropic ATP receptors (P2X2/P2X3 on taste nerves as well as metabotropic (P2Y purinergic receptors on taste bud cells. The action of the extracellular ATP is terminated by ectonucleotidases, ultimately generating adenosine, which itself can activate one or more G-protein coupled adenosine receptors: A1, A2A, A2B, and A3. Here we investigated the expression of adenosine receptors in mouse taste buds at both the nucleotide and protein expression levels. Of the adenosine receptors, only A2B receptor (A2BR is expressed specifically in taste epithelia. Further, A2BR is expressed abundantly only in a subset of taste bud cells of posterior (circumvallate, foliate, but not anterior (fungiform, palate taste fields in mice. Analysis of double-labeled tissue indicates that A2BR occurs on Type II taste bud cells that also express Gα14, which is present only in sweet-sensitive taste cells of the foliate and circumvallate papillae. Glossopharyngeal nerve recordings from A2BR knockout mice show significantly reduced responses to both sucrose and synthetic sweeteners, but normal responses to tastants representing other qualities. Thus, our study identified a novel regulator of sweet taste, the A2BR, which functions to potentiate sweet responses in posterior lingual taste fields.

  13. New chromene scaffolds for adenosine A(2A) receptors: synthesis, pharmacology and structure-activity relationships.

    Science.gov (United States)

    Areias, Filipe; Costa, Marta; Castro, Marián; Brea, José; Gregori-Puigjané, Elisabet; Proença, M Fernanda; Mestres, Jordi; Loza, María I

    2012-08-01

    In silico screening of a collection of 1584 academic compounds identified a small molecule hit for the human adenosine A(2A) receptor (pK(i) = 6.2) containing a novel chromene scaffold (3a). To explore the structure-activity relationships of this new chemical series for adenosine receptors, a focused library of 43 2H-chromene-3-carboxamide derivatives was synthesized and tested in radioligand binding assays at human adenosine A(1), A(2A), A(2B) and A(3) receptors. The series was found to be enriched with bioactive compounds for adenosine receptors, with 14 molecules showing submicromolar affinity (pK(i) ≥ 6.0) for at least one adenosine receptor subtype. These results provide evidence that the chromene scaffold, a core structure present in natural products from a wide variety of plants, vegetables, and fruits, constitutes a valuable source for novel therapeutic agents. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  14. Receptor tyrosine kinases and schistosome reproduction: new targets for chemotherapy

    Directory of Open Access Journals (Sweden)

    Marion eMorel

    2014-07-01

    Full Text Available Schistosome parasites still represent a serious public health concern and a major economic problem in developing countries. Pathology of schistosomiasis is mainly due to massive egg production by these parasites and to inflammatory responses raised against the eggs which are trapped in host tissues. Tyrosine kinases (TKs are key molecules that control cell differentiation and proliferation and they already represent important targets in cancer therapy. During the recent years, it has been shown that receptor tyrosine kinases (RTK signaling was active in reproductive organs and that it could regulate sexual maturation of schistosomes and egg production. This opens interesting perspectives for the control of transmission and pathogenesis of schistosomiasis based on new therapies targeting schistosome RTKs. This review relates the numerous data showing the major roles of kinase signaling in schistosome reproduction. It describes the conserved and particular features of schistosome RTKs, their implication in gametogenesis and reproduction processes and summarizes recent works indicating that RTKs and their signaling partners are interesting chemotherapeutical targets in new programs of control.

  15. Identification of novel androgen receptor target genes in prostate cancer

    Directory of Open Access Journals (Sweden)

    Gerald William L

    2007-06-01

    Full Text Available Abstract Background The androgen receptor (AR plays critical roles in both androgen-dependent and castrate-resistant prostate cancer (PCa. However, little is known about AR target genes that mediate the receptor's roles in disease progression. Results Using Chromatin Immunoprecipitation (ChIP Display, we discovered 19 novel loci occupied by the AR in castrate resistant C4-2B PCa cells. Only four of the 19 AR-occupied regions were within 10-kb 5'-flanking regulatory sequences. Three were located up to 4-kb 3' of the nearest gene, eight were intragenic and four were in gene deserts. Whereas the AR occupied the same loci in C4-2B (castrate resistant and LNCaP (androgen-dependent PCa cells, differences between the two cell lines were observed in the response of nearby genes to androgens. Among the genes strongly stimulated by DHT in C4-2B cells – D-dopachrome tautomerase (DDT, Protein kinase C delta (PRKCD, Glutathione S- transferase theta 2 (GSTT2, Transient receptor potential cation channel subfamily V member 3 (TRPV3, and Pyrroline-5-carboxylate reductase 1 (PYCR1 – most were less strongly or hardly stimulated in LNCaP cells. Another AR target gene, ornithine aminotransferase (OAT, was AR-stimulated in a ligand-independent manner, since it was repressed by AR siRNA knockdown, but not stimulated by DHT. We also present evidence for in vivo AR-mediated regulation of several genes identified by ChIP Display. For example, PRKCD and PYCR1, which may contribute to PCa cell growth and survival, are expressed in PCa biopsies from primary tumors before and after ablation and in metastatic lesions in a manner consistent with AR-mediated stimulation. Conclusion AR genomic occupancy is similar between LNCaP and C4-2B cells and is not biased towards 5' gene flanking sequences. The AR transcriptionally regulates less than half the genes nearby AR-occupied regions, usually but not always, in a ligand-dependent manner. Most are stimulated and a few are

  16. Timosaponin AIII induces antiplatelet and antithrombotic activity via Gq-mediated signaling by the thromboxane A2 receptor

    Science.gov (United States)

    Cong, Yue; Wang, Limei; Peng, Renjun; Zhao, Yang; Bai, Fan; Yang, Chao; Liu, Xiaolan; Wang, Daqian; Ma, Baiping; Cong, Yuwen

    2016-01-01

    The thromboxane (Tx) A2 pathway is a major contributor to the amplification of initial platelet activation and is therefore a key drug target. To identify potent small-molecule inhibitors of the thromboxane prostaglandin (TP) receptor, we screened a small steroidal saponin library using U46619-induced rat platelet aggregation assays. Timosaponin AIII (TAIII) was identified as a potent inhibitor of U46619-induced rat platelet aggregation and exhibited superior selectivity for the TP receptor versus other G protein-coupled receptors and a PKC activator. TAIII inhibited U46619-induced rat platelet aggregation independent of increases in cAMP and cGMP and the inhibition of TxA2 production. Both PKC and PLC activators restored TAIII-inhibited platelet aggregation, whereas TAIII did not inhibit platelet aggregation induced by co-activation of the G12/13 and Gz pathways. Furthermore, TAIII did not affect the platelet shape change or ROCK2 phosphorylation evoked by low-dose U46619. In vivo, TAIII prolonged tail bleeding time, reduced the mortality of animals with acute pulmonary thromboembolism and significantly reduced venous thrombus weight. Our study suggests that TAIII, by preferentially targeting Gq-mediated PLC/PKC signaling from the TP receptor, induces stronger in vitro antiplatelet activity and in vivo antithrombotic effects and may be an excellent candidate for the treatment of thrombotic disorders. PMID:27934923

  17. Toll-like receptors as targets for immune disorders.

    LENUS (Irish Health Repository)

    Keogh, Brian

    2012-02-01

    Since the identification of the first Toll-like receptor (TLR) in humans in 1997, understanding of the molecular basis for innate immunity has increased significantly. The TLR family and downstream signalling pathways have been extensively characterised, There is now significant evidence suggesting a role for TLRs in human inflammatory and immune diseases such as rheumatoid arthritis, diabetes, allergy\\/asthma and atherosclerosis. Various approaches have been taken to identify novel therapeutic agents targeting TLRs including biologics, small molecules and nucleic acid-based drugs. Several are now being evaluated in the clinic and showing promise against various diseases. This review paper outlines the recent advances in the understanding of TLR biology and highlights novel TLR agonists and antagonists in development for the treatment of immune diseases.

  18. Engineering therapeutic antibodies targeting G-protein-coupled receptors.

    Science.gov (United States)

    Jo, Migyeong; Jung, Sang Taek

    2016-02-05

    G-protein-coupled receptors (GPCRs) are one of the most attractive therapeutic target classes because of their critical roles in intracellular signaling and their clinical relevance to a variety of diseases, including cancer, infection and inflammation. However, high conformational variability, the small exposed area of extracellular epitopes and difficulty in the preparation of GPCR antigens have delayed both the isolation of therapeutic anti-GPCR antibodies as well as studies on the structure, function and biochemical mechanisms of GPCRs. To overcome the challenges in generating highly specific anti-GPCR antibodies with enhanced efficacy and safety, various forms of antigens have been successfully designed and employed for screening with newly emerged systems based on laboratory animal immunization and high-throughput-directed evolution.

  19. Chemokine receptors as new molecular targets for antiviral therapy.

    Science.gov (United States)

    Santoro, F; Vassena, L; Lusso, P

    2004-04-01

    Extraordinary advancements have been made over the past decade in our understanding of the molecular mechanism of human immunodeficiency virus (HIV) entry into cells. The external HIV envelope glycoprotein, gp120, sequentially interacts with two cellular receptor molecules, the CD4 glycoprotein and a chemokine receptor, such as CCR5 or CXCR4, leading to the activation of the fusogenic domain of the transmembrane viral glycoprotein, gp41, which changes its conformation to create a hairpin structure that eventually triggers fusion between the viral and cellular membranes. Each of these discrete steps in the viral entry process represents a potential target for new antiviral agents. Current efforts to develop safe and effective HlV entry inhibitors are focused on naturally occurring proteins (e.g., chemokines, antibodies), engineered or modified derivatives of natural proteins (e.g., multimerized soluble CD4, gp41--or chemokine--derived synthetic peptides), as well as small synthetic compounds obtained either by high-throughput screening of large compound libraries or by structure-guided rational design. The recent introduction in therapy of the first fusion inhibitor, the gp41-derived synthetic peptide T20, heralds a new era in the treatment of AIDS, which will hopefully lead to more effective multi-drug regimens with reduced adverse effects for the patients.

  20. Targeted Inhibition of Multiple Receptor Tyrosine Kinases in Mesothelioma

    Directory of Open Access Journals (Sweden)

    Wen-Bin Ou

    2011-01-01

    Full Text Available The receptor tyrosine kinases (RTKs epidermal growth factor receptor (EGFR and MET are activated in subsets of mesothelioma, suggesting that these kinases might represent novel therapeutic targets in this notoriously chemotherapy-resistant cancer. However, clinical trials have shown little activity for EGFR inhibitors in mesothelioma. Despite the evidence for RTK activation in mesothelioma pathogenesis, it is unclear whether transforming activity is dependent on an individual kinase oncoprotein or the coordinated activity of multiple kinases. Using phospho-RTK and immunoblot assays, we herein demonstrate activation of multiple RTKs (EGFR, MET, AXL, and ERBB3 in individual mesothelioma cell lines but not in normal mesothelioma cells. Inhibition of mesothelioma multi-RTK signaling was accomplished using combinations of RTK direct inhibitors or by inhibition of the RTK chaperone, heat shock protein 90 (HSP90. Multi-RTK inhibition by the HSP90 inhibitor 17-allyloamino-17demethoxygeldanamycin (17-AAG had a substantially greater effect on mesothelioma proliferation and survival compared with inhibition of individual activated RTKs. HSP90 inhibition also suppressed phosphorylation of down-stream signaling intermediates (AKT, mitogen-activated protein kinase, and S6; upregulated the p53, p21, and p27 cell cycle checkpoints; induced G2 phase arrest; induced caspase 3/7 activity; and led to an increase in the sub-G1 apoptotic population. These compelling proapoptotic and antiproliferative responses indicate that HSP90 inhibition warrants clinical evaluation as a novel therapeutic strategy in mesothelioma.

  1. Discovery of Potent and Highly Selective A2B Adenosine Receptor Antagonist Chemotypes.

    Science.gov (United States)

    El Maatougui, Abdelaziz; Azuaje, Jhonny; González-Gómez, Manuel; Miguez, Gabriel; Crespo, Abel; Carbajales, Carlos; Escalante, Luz; García-Mera, Xerardo; Gutiérrez-de-Terán, Hugo; Sotelo, Eddy

    2016-03-10

    Three novel families of A2B adenosine receptor antagonists were identified in the context of the structural exploration of the 3,4-dihydropyrimidin-2(1H)-one chemotype. The most appealing series contain imidazole, 1,2,4-triazole, or benzimidazole rings fused to the 2,3-positions of the parent diazinone core. The optimization process enabled identification of a highly potent (3.49 nM) A2B ligand that exhibits complete selectivity toward A1, A2A, and A3 receptors. The results of functional cAMP experiments confirmed the antagonistic behavior of representative ligands. The main SAR trends identified within the series were substantiated by a molecular modeling study based on a receptor-driven docking model constructed on the basis of the crystal structure of the human A2A receptor.

  2. Correlation of M-type phospholipase A2 receptor genetic polymorphism with idiopathic membranous nephropathy

    Institute of Scientific and Technical Information of China (English)

    周广宇

    2013-01-01

    Objective To investigate the correlation of M-typephos pholipase A2receptor(PLA2R) genetic polymorphism in two single nucleotide polymorphisms(SNPs) with idiopathic membranous nephropathy(IMN) of Chinese

  3. Asialoglycoprotein receptor targeted imaging using Tc-99m galactosylated chitosan

    Energy Technology Data Exchange (ETDEWEB)

    Kim, E. M.; Jeong, H. J.; Kim, B. C.; Kim, C. K [Wonkang University College of Medicine, Iksan (Korea, Republic of)

    2004-07-01

    The asialoglycoprotein receptor (ASGP-R) is expressed on liver hepatocytes. Chitosan conjugates of galactose have shown to be specifically taken up by liver parenchymal cells via ASGP-R. In this study, Tc-99m hydrazino nicotinamide (HYNIC)-galactosylated chitosan (HYNIC-GC) was synthesized and evaluated as a targeted agent for the imaging of hepatocytes. GC was obtained after coupling of lactobionic acid as the galactose moiety and coupled with HYNIC. HYNIC-GC was radiolabeled with Tc-99m using stannous chloride and tricine as reducing agent and coligand respectively. Hepatic uptake property of Tc-99m HYNIC-GC was studied in female Balb/C mouse. Tc-99m HYNIC--GC and Tc-99m HYNIC-Chitosan as a control were intravenously injected into mice. Receptor binding was identified by coinjection with 50 mM and 80mM free galactose respectively. Biodistribution was determined at three different time points. The level of galactose substitution was 7.6%. Labeling efficiency was >90% both in vitro and serum up to 24 h. Tc-99m HYNIC-GC injected via tail vein of mice showed high selectivity of liver. On the other hands, Tc-99m HC without galactose group showed low uptake (Fig. 1A, 1B). Hepatic uptake of Tc-99m HYNIC-GC was dramatically blocked by 50 mM and 80 mM free galactose coinjection (Fig. 1C, 1D). The liver accumulated about 14 percent injected dose per gram (%ID/g) up to 120 min after injection. Tc-99m HYNIC-GC showed specific and rapid targeting to liver. It is a promising specific radiopharmaceutical with potential applications in the imaging of liver parenchymal cells.

  4. A novel, potent, and specific ephrinA1-based cytotoxin against EphA2 receptor expressing tumor cells.

    Science.gov (United States)

    Wykosky, Jill; Gibo, Denise M; Debinski, Waldemar

    2007-12-01

    We have previously shown that the EphA2 receptor tyrosine kinase is overexpressed in glioblastoma multiforme (GBM) and represents a novel, attractive therapeutic target for the treatment of brain tumors. Here, we have developed an EphA2-targeted agent, ephrinA1-PE38QQR, a novel cytotoxin composed of ephrinA1, a ligand for EphA2, and PE38QQR, a mutated form of Pseudomonas aeruginosa exotoxin A. EphrinA1-PE38QQR showed potent and dose-dependent killing of GBM cells overexpressing the EphA2 receptor in cell viability and clonogenic survival assays, with an average IC(50) of approximately 10(-11) mol/L. The conjugate was also highly effective in killing breast and prostate cancer cells overexpressing EphA2. The cytotoxic effect of ephrinA1-PE38QQR was specific, as it was neutralized by an excess of EphA2 ligands. Moreover, normal human endothelial cells and breast cancer cells that do not overexpress EphA2, as well as GBM cells that have down-regulated EphA2, were not susceptible to the cytotoxin. EphrinA1-PE38QQR-mediated cytotoxicity induced caspase-dependent apoptosis, which was, however, not responsible for cell death in response to the conjugate. In addition, the conjugate elicited no changes in the activity of survival pathways such as phosphoinositide 3-kinase, measured by AKT phosphorylation. This is the first attempt to create a cytotoxic therapy using any of the ephrin ligands of either class (A or B) conjugated to a bacterial toxin. EphrinA1-PE38QQR is very potent and specific, produces cell death that is caspase independent, and forms the basis for the further development of clinically applicable EphA2-targeted cytotoxins.

  5. A Novel Gene Delivery System Targeting Urokinase Receptor

    Institute of Scientific and Technical Information of China (English)

    Xing-Hui SUN; Li TAN; Chun-Yang LI; Chang TONG; Jin FAN; Ping LI; Yun-Song ZHU

    2004-01-01

    Recombinant proteins that combine different functions required for cell targeting and intracellular delivery of DNA present an attractive approach for the development of nonviral gene delivery vectors. Here, we described a novel protein termed ATF-lys10 which facilitated cell-specific gene transfer via receptor-mediated endocytosis. ATF-lys 10 was composed of the amino-terminal fragment of urokinase and ten lysines at the carboxyl terminus. Bacterially expressed ATF-lys 10 protein existed in soluble form, and had antigenicity of human urokinase. Purified ATF-lys 10 specifically bound to uPAR-expressing cells and formed protein-DNA complexes with plasmid pGL3-control. After neutralization of excess negative charge with poly-L-lysine, these complexes served as a specific gene delivery vector for uPAR-expressing cells. Lysosomotropic compounds, such as chloroquine, drastically increased the ATF-lysl0 mediated gene delivery efficiency. Our results suggest that the recombinant protein ATF-lys 10 with the properties of DNA binding and tumor cell targeting represents a promising method for gene transfer and expression in tumor cells.

  6. Targeting Gallium to Cancer Cells through the Folate Receptor

    Directory of Open Access Journals (Sweden)

    Nerissa Viola-Villegas

    2008-01-01

    Full Text Available The development of gallium(III compounds as anti-cancer agents for both treatment and diagnosis is a rapidly developing field of research. Problems remain in exploring the full potential of gallium(III as a safe and successful therapeutic agent or as an imaging agent. One of the major issues is that gallium(III compounds have little tropism for cancer cells. We have combined the targeting properties of folic acid (FA with long chain liquid polymer poly(ethylene glycol (PEG ‘spacers’. This FA-PEG unit has been coupled to the gallium coordination complex of 1,4,7,10-tetraazacyclo-dodecane-N,N′,N′′,N′′′-tetraacetic acid (DOTA through amide linkages for delivery into target cells overexpressing the folate receptor (FR. In vitro cytotoxicity assays were conducted against a multi-drug resistant ovarian cell line (A2780/AD that overexpresses the FR and contrasted against a FR free Chinese hamster ovary (CHO cell line. Results are rationalized taking into account stability studies conducted in RPMI 1640 media and HEPES buffer at pH 7.4.

  7. Ryanodine receptors as pharmacological targets for heart disease

    Institute of Scientific and Technical Information of China (English)

    Marco SANTONASTASI; Xander H T WEHRENS

    2007-01-01

    Calcium release from intracellular stores plays an important role in the regulationof muscle contraction and electrical signals that determine the heart rhythm. Theryanodine receptor (RyR) is the major calcium (Ca2+) release channel required forexcitation-contraction coupling in the heart. Recent studies have demonstratedthat RyR are macromolecular complexes comprising of 4 pore-forming channelsubunits, each of which is associated with regulatory subunits. Clinical andexperimental studies over the past 5 years have provided compelling evidencethat intracellular Ca2+release channels play a pivotal role in the development ofcardiac arrhythmias and heart failure. Changes in the channel regulation andsubunit composition are believed to cause diastolic calcium leakage from thesarcoplasmic reticulum, which could trigger arrhythmias and weaken cardiaccontractility. Therefore, cardiac RyR have emerged as potential therapeutic tar-gets for the treatment of heart disease. Consequently, there is a strong desire toidentify and/or develop novel pharmacological agents that may target these Ca2+signaling pathways. Pharmacological agents known to modulate RyR in the heart,and their potential application towards the treatment of heart disease are dis-cussed in this review.

  8. Pre-synaptic adenosine A2A receptors control cannabinoid CB1 receptor-mediated inhibition of striatal glutamatergic neurotransmission.

    Science.gov (United States)

    Martire, Alberto; Tebano, Maria Teresa; Chiodi, Valentina; Ferreira, Samira G; Cunha, Rodrigo A; Köfalvi, Attila; Popoli, Patrizia

    2011-01-01

    An interaction between adenosine A(2A) receptors (A(2A) Rs) and cannabinoid CB(1) receptors (CB(1) Rs) has been consistently reported to occur in the striatum, although the precise mechanisms are not completely understood. As both receptors control striatal glutamatergic transmission, we now probed the putative interaction between pre-synaptic CB(1) R and A(2A) R in the striatum. In extracellular field potentials recordings in corticostriatal slices from Wistar rats, A(2A) R activation by CGS21680 inhibited CB(1) R-mediated effects (depression of synaptic response and increase in paired-pulse facilitation). Moreover, in superfused rat striatal nerve terminals, A(2A) R activation prevented, while A(2A) R inhibition facilitated, the CB(1) R-mediated inhibition of 4-aminopyridine-evoked glutamate release. In summary, the present study provides converging neurochemical and electrophysiological support for the occurrence of a tight control of CB(1) R function by A(2A) Rs in glutamatergic terminals of the striatum. In view of the key role of glutamate to trigger the recruitment of striatal circuits, this pre-synaptic interaction between CB(1) R and A(2A) R may be of relevance for the pathogenesis and the treatment of neuropsychiatric disorders affecting the basal ganglia.

  9. Regulatory effects of adenosine A2A receptors on psychomotor ability and mood behavior of mice

    Directory of Open Access Journals (Sweden)

    Li JIANG

    2011-07-01

    Full Text Available Objective To explore the effects of gene knock-out,agonist or inhibitor of adenosine A2A receptor on the locomotor activity,and anxiety-or depression-like behavior of mice.Methods Male C57BL/6 mice,comprising those underwent gene knock-out of adenosine A2A receptor(A2AKO and their wild-type(WT littermates,were assigned into A2AKO group and WT group.Another batch of male C57BL/6,specific-pathogen-free(SPF mice,were assigned into SCH58261 group,CGS21680 group and control group.Mice of aforesaid 3 groups were transperitoneally administered with SCH58261,a specific inhibitor of adenosine A2A receptor at a dose of 2mg/kg,CGS21680,a specific agonist of adenosine A2A receptor at a dose of 0.5mg/kg,and vehicle(0.25ml,comprising DMSO and saline,respectively.Ten minutes after injection,mice of the 3 groups underwent open-field test,elevated plus-maze test and forced swimming test to detect their locomotor activity,anxiety-and depression-like behavior.Results a Compared with WT group,the total movement distance decreased(P 0.05.b Compared with control group,the total movement distance decreased and the stay time in the peripheral area increased significantly in the open field test(P 0.05.Conclusions The agonist of adenosine A2A receptor may depress the spontaneous motility and exploratory behavior,and exacerbate the anxiety and depression,and it simulates the effect induced by knock-out of A2A receptor gene,but it is opposite to the effect induced by A2A receptor inhibitor.

  10. Deletion of striatal adenosine A(2A) receptor spares latent inhibition and prepulse inhibition but impairs active avoidance learning.

    Science.gov (United States)

    Singer, Philipp; Wei, Catherine J; Chen, Jiang-Fan; Boison, Detlev; Yee, Benjamin K

    2013-04-01

    Following early clinical leads, the adenosine A(2A)R receptor (A(2A)R) has continued to attract attention as a potential novel target for treating schizophrenia, especially against the negative and cognitive symptoms of the disease because of A(2A)R's unique modulatory action over glutamatergic in addition to dopaminergic signaling. Through (i) the antagonistic interaction with the dopamine D(2) receptor, and (ii) the regulation of glutamate release and N-methyl-d-aspartate receptor function, striatal A(2A)R is ideally positioned to fine-tune the dopamine-glutamate balance, the disturbance of which is implicated in the pathophysiology of schizophrenia. However, the precise function of striatal A(2A)Rs in the regulation of schizophrenia-relevant behavior is poorly understood. Here, we tested the impact of conditional striatum-specific A(2A)R knockout (st-A(2A)R-KO) on latent inhibition (LI) and prepulse inhibition (PPI) - behavior that is tightly regulated by striatal dopamine and glutamate. These are two common cross-species translational tests for the assessment of selective attention and sensorimotor gating deficits reported in schizophrenia patients; and enhanced performance in these tests is associated with antipsychotic drug action. We found that neither LI nor PPI was significantly affected in st-A(2A)R-KO mice, although a deficit in active avoidance learning was identified in these animals. The latter phenotype, however, was not replicated in another form of aversive conditioning - namely, conditioned taste aversion. Hence, the present study shows that neither learned inattention (as measured by LI) nor sensory gating (as indexed by PPI) requires the integrity of striatal A(2A)Rs - a finding that may undermine the hypothesized importance of A(2A)R in the genesis and/or treatment of schizophrenia.

  11. Regulation of TrkB receptor translocation to lipid rafts by adenosine A2A receptors and its functional implications for BDNF-induced regulation of synaptic plasticity

    OpenAIRE

    Assaife-Lopes, Natália; Sousa, Vasco C.; Pereira, Daniela B.; Ribeiro, Joaquim A.; Sebastião, Ana M.

    2013-01-01

    Brain-derived neurotrophic factor (BDNF) signalling is critical for neuronal development and transmission. Recruitment of TrkB receptors to lipid rafts has been shown to be necessary for the activation of specific signalling pathways and modulation of neurotransmitter release by BDNF. Since TrkB receptors are known to be modulated by adenosine A2A receptor activation, we hypothesized that activation of A2A receptors could influence TrkB receptor localization among different membrane microdoma...

  12. Both A1 and A2a purine receptors regulate striatal acetylcholine release.

    Science.gov (United States)

    Brown, S J; James, S; Reddington, M; Richardson, P J

    1990-07-01

    The receptors responsible for the adenosine-mediated control of acetylcholine release from immunoaffinity-purified rat striatal cholinergic nerve terminals have been characterized. The relative affinities of three analogues for the inhibitory receptor were (R)-phenylisopropyladenosine greater than cyclohexyladenosine greater than N-ethylcarboxamidoadenosine (NECA), with binding being dependent of the presence of Mg2+ and inhibited by 5'-guanylylimidodiphosphate [Gpp(NH)p] and adenosine receptor antagonists. Adenosine A1 receptor agonists inhibited forskolin-stimulated cholinergic adenylate cyclase activity, with an IC50 of 0.5 nM for (R)-phenylisopropyladenosine and 500 nM for (S)-phenylisopropyladenosine. A1 agonists inhibited acetylcholine release at concentrations approximately 10% of those required to inhibit the cholinergic adenylate cyclase. High concentrations (1 microM) of adenosine A1 agonists were less effective in inhibiting both adenylate cyclase and acetylcholine release, due to the presence of a lower affinity stimulatory A2 receptor. Blockade of the A1 receptor with 8-cyclopentyl-1,3-dipropylxanthine revealed a half-maximal stimulation by NECA of the adenylate cyclase at 10 nM, and of acetylcholine release at approximately 100 nM. NECA-stimulated adenylate cyclase activity copurified with choline acetyltransferase in the preparation of the cholinergic nerve terminals, suggesting that the striatal A2 receptor is localized to cholinergic neurones. The possible role of feedback inhibitory and stimulatory receptors on cholinergic nerve terminals is discussed.

  13. Identification of estrogen receptor-related receptor gamma as a direct transcriptional target of angiogenin.

    Directory of Open Access Journals (Sweden)

    Jian Ang

    Full Text Available Nuclear translocation of angiogenin (ANG is essential for the proliferation of its target cells. ANG promotes rRNA synthesis, while whether it regulates mRNA transcription remains unknown. Using the chromatin immunoprecipitation method, we have identified 12 ANG-binding sequences. One of these sequences lies in the estrogen receptor-related receptor gamma (ERRγ gene which we designated as ANG-Binding Sequence within ERRγ (ABSE. ABSE exhibited ANG-dependent repressor activity in the luciferase reporter system. Down-regulation of ANG increased ERRγ expression, and active gene marker level at the ABSE region. The expression levels of ERRγ targets genes, p21(WAF/CIP and p27(KIP1, and the occupation of ERRγ on their promoter regions were increased in ANG-deficient cells accordingly. Furthermore, knockdown of ERRγ promoted the proliferation rate in ANG-deficient breast cancer cells. Finally, immunohistochemistry staining showed negative correlation between ANG and ERRγ in breast cancer tissue. Altogether, our study provides evidence that nuclear ANG directly binds to the ABSE of ERRγ gene and inhibits ERRγ transcription to promote breast cancer cell proliferation.

  14. Large-scale functional expression of WT and truncated human adenosine A2A receptor in Pichia pastoris bioreactor cultures

    Directory of Open Access Journals (Sweden)

    Strange Philip G

    2008-10-01

    Full Text Available Abstract Background The large-scale production of G-protein coupled receptors (GPCRs for functional and structural studies remains a challenge. Recent successes have been made in the expression of a range of GPCRs using Pichia pastoris as an expression host. P. pastoris has a number of advantages over other expression systems including ability to post-translationally modify expressed proteins, relative low cost for production and ability to grow to very high cell densities. Several previous studies have described the expression of GPCRs in P. pastoris using shaker flasks, which allow culturing of small volumes (500 ml with moderate cell densities (OD600 ~15. The use of bioreactors, which allow straightforward culturing of large volumes, together with optimal control of growth parameters including pH and dissolved oxygen to maximise cell densities and expression of the target receptors, are an attractive alternative. The aim of this study was to compare the levels of expression of the human Adenosine 2A receptor (A2AR in P. pastoris under control of a methanol-inducible promoter in both flask and bioreactor cultures. Results Bioreactor cultures yielded an approximately five times increase in cell density (OD600 ~75 compared to flask cultures prior to induction and a doubling in functional expression level per mg of membrane protein, representing a significant optimisation. Furthermore, analysis of a C-terminally truncated A2AR, terminating at residue V334 yielded the highest levels (200 pmol/mg so far reported for expression of this receptor in P. pastoris. This truncated form of the receptor was also revealed to be resistant to C-terminal degradation in contrast to the WT A2AR, and therefore more suitable for further functional and structural studies. Conclusion Large-scale expression of the A2AR in P. pastoris bioreactor cultures results in significant increases in functional expression compared to traditional flask cultures.

  15. Therapeutic Opportunities for Caffeine and A2A Receptor Antagonists in Retinal Diseases.

    Science.gov (United States)

    Boia, Raquel; Ambrósio, António Francisco; Santiago, Ana Raquel

    2016-01-01

    Caffeine, the major component of coffee, is the most consumed psychostimulant in the world. Caffeine is an adenosine analog and acts as a nonselective adenosine receptor antagonist. The majority of the effects of caffeine are mainly mediated by the blockade of adenosine receptors, and the proved neuroprotective effects of caffeine in brain disorders have been mimicked by the blockade of adenosine A2A receptor (A2AR). A growing body of evidence demonstrates that microglia-mediated neuroinflammation plays a key role in the pathophysiology of brain and retinal diseases. Moreover, the control of microglia reactivity by blocking A2AR has been proposed to be the mechanism underlying the observed protective effects of caffeine. Hence, it is conceivable that caffeine and A2AR antagonists offer therapeutic value for the treatment of retinal diseases, mainly those involving microglia-mediated neuroinflammation.

  16. Allosteric interactions between agonists and antagonists within the adenosine A2A receptor-dopamine D2 receptor heterotetramer.

    Science.gov (United States)

    Bonaventura, Jordi; Navarro, Gemma; Casadó-Anguera, Verònica; Azdad, Karima; Rea, William; Moreno, Estefanía; Brugarolas, Marc; Mallol, Josefa; Canela, Enric I; Lluís, Carme; Cortés, Antoni; Volkow, Nora D; Schiffmann, Serge N; Ferré, Sergi; Casadó, Vicent

    2015-07-07

    Adenosine A2A receptor (A2AR)-dopamine D2 receptor (D2R) heteromers are key modulators of striatal neuronal function. It has been suggested that the psychostimulant effects of caffeine depend on its ability to block an allosteric modulation within the A2AR-D2R heteromer, by which adenosine decreases the affinity and intrinsic efficacy of dopamine at the D2R. We describe novel unsuspected allosteric mechanisms within the heteromer by which not only A2AR agonists, but also A2AR antagonists, decrease the affinity and intrinsic efficacy of D2R agonists and the affinity of D2R antagonists. Strikingly, these allosteric modulations disappear on agonist and antagonist coadministration. This can be explained by a model that considers A2AR-D2R heteromers as heterotetramers, constituted by A2AR and D2R homodimers, as demonstrated by experiments with bioluminescence resonance energy transfer and bimolecular fluorescence and bioluminescence complementation. As predicted by the model, high concentrations of A2AR antagonists behaved as A2AR agonists and decreased D2R function in the brain.

  17. Toll-like receptors as targets for allergen immunotherapy.

    Science.gov (United States)

    Aryan, Zahra; Rezaei, Nima

    2015-12-01

    Toll-like receptors (TLRs) are novel and promising targets for allergen immunotherapy. Bench studies suggest that TLR agonists reduce Th2 responses and ameliorate airway hyper-responsiveness. In addition, clinical trials are at initial phases to evaluate the safety and efficacy of TLR agonists for the allergen immunotherapy of patients with allergic rhinitis and asthma. (Figure is included in full-text article.) To date, two allergy vaccine-containing TLR agonists have been investigated in clinical trials; Pollinex Quattro and AIC. The former contains monophosphoryl lipid, a TLR4 agonist and the latter contains, CpG motifs activating the TLR9 cascade. Preseasonal subcutaneous injection of both of these allergy vaccines has been safe and efficacious in control of nasal symptoms of patients with allergic rhinitis. CRX-675 (a TLR4 agonist), AZD8848 (a TLR7 agonist), VTX-1463 (a TLR8 agonist) and 1018 ISS and QbG10 (TLR9 agonists) are currently in clinical development for allergic rhinitis and asthma. TLR agonists herald promising results for allergen immunotherapy of patients with allergic rhinitis and asthma. Future research should be directed at utilizing these agents for immunotherapy of food allergy (for instance, peanut allergy) as well.

  18. Asialoglycoprotein receptor targeted delivery of doxorubicin nanoparticles for hepatocellular carcinoma.

    Science.gov (United States)

    Pranatharthiharan, Sandhya; Patel, Mitesh D; Malshe, Vinod C; Pujari, Vaishali; Gorakshakar, Ajit; Madkaikar, Manisha; Ghosh, Kanjaksha; Devarajan, Padma V

    2017-11-01

    We report asialoglycoprotein receptor (ASGPR)-targeted doxorubicin hydrochloride (Dox) nanoparticles (NPs) for hepatocellular carcinoma (HCC). Polyethylene sebacate (PES)-Gantrez® AN 119 Dox NPs of average size 220 nm with PDI < 0.62 and ∼20% Dox loading were prepared by modified nanoprecipitation. ASGPR ligands, pullulan (Pul), arabinogalactan (AGn), and the combination (Pul-AGn), were anchored by adsorption. Ligand anchoring enabled high liver uptake with a remarkable hepatocyte:nonparenchymal cell ratio of 85:15. Furthermore, Pul-AGn NPs exhibited an additive effect implying incredibly high hepatocyte accumulation. Galactose-mediated competitive inhibition confirmed ASGPR-mediated uptake of ligand-anchored NPs in HepG2 cell lines. Subacute toxicity in rats confirmed the safety of the NP groups. However, histopathological evaluation suggested mild renal toxicity of AGn. Pul NPs revealed sustained reduction in tumor volume in PLC/PRF/5 liver tumor-bearing Nod/Scid mice up to 46 days. Extensive tumor necrosis, reduced collagen content, reduction in the HCC biomarker serum α-fetoprotein (p < 0.05), a mitotic index of 1.135 (day 46), and tumor treated/tumor control (T/C) values of <0.42 signified superior efficacy of Pul NPs. Furthermore, weight gain in the NP groups, and no histopathological alterations indicated that they were well tolerated by the mice. The high efficacy coupled with greater safety portrayed Pul Dox NPs as a promising nanocarrier for improved therapy of HCC.

  19. The A2B adenosine receptor impairs the maturation and immunogenicity of dendritic cells.

    Science.gov (United States)

    Wilson, Jeffrey M; Ross, William G; Agbai, Oma N; Frazier, Renea; Figler, Robert A; Rieger, Jayson; Linden, Joel; Ernst, Peter B

    2009-04-15

    The endogenous purine nucleoside adenosine is an important antiinflammatory mediator that contributes to the control of CD4(+) T cell responses. While adenosine clearly has direct effects on CD4(+) T cells, it remains to be determined whether actions on APC such as dendritic cells (DC) are also important. In this report we characterize DC maturation and function in BMDC stimulated with LPS in the presence or absence of the nonselective adenosine receptor agonist NECA (5'-N-ethylcarboxamidoadenosine). We found that NECA inhibited TNF-alpha and IL-12 in a concentration-dependent manner, whereas IL-10 production was increased. NECA-treated BMDC also expressed reduced levels of MHC class II and CD86 and were less effective at stimulating CD4(+) T cell proliferation and IL-2 production compared with BMDC exposed to vehicle control. Based on real-time RT-PCR, the A(2A) adenosine receptor (A(2A)AR) and A(2B)AR were the predominant adenosine receptors expressed in BMDC. Using adenosine receptor subtype selective antagonists and BMDC derived from A(2A)AR(-/-) and A(2B)AR(-/-)mice, it was shown that NECA modulates TNF-alpha, IL-12, IL-10, and CD86 responses predominantly via A(2B)AR. These data indicate that engagement of A(2B)AR modifies murine BMDC maturation and suggest that adenosine regulates CD4(+) T cell responses by selecting for DC with impaired immunogencity.

  20. Neuropeptide FF receptors as novel targets for limbic seizure attenuation.

    Science.gov (United States)

    Portelli, Jeanelle; Meurs, Alfred; Bihel, Frederic; Hammoud, Hassan; Schmitt, Martine; De Kock, Joery; Utard, Valerie; Humbert, Jean-Paul; Bertin, Isabelle; Buffel, Ine; Coppens, Jessica; Tourwe, Dirk; Maes, Veronique; De Prins, An; Vanhaecke, Tamara; Massie, Ann; Balasubramaniam, Ambikaipakan; Boon, Paul; Bourguignon, Jean-Jacques; Simonin, Frederic; Smolders, Ilse

    2015-08-01

    Neuropeptide Y (NPY) is a well established anticonvulsant and first-in-class antiepileptic neuropeptide. In this study, the controversial role of NPY1 receptors in epilepsy was reassessed by testing two highly selective NPY1 receptor ligands and a mixed NPY1/NPFF receptor antagonist BIBP3226 in a rat model for limbic seizures. While BIBP3226 significantly attenuated the pilocarpine-induced seizures, neither of the highly selective NPY1 receptor ligands altered the seizure severity. Administration of the NPFF1/NPFF2 receptor antagonist RF9 also significantly attenuated limbic seizure activity. To further prove the involvement of NPFF receptors in these seizure-modulating effects, low and high affinity antagonists for the NPFF receptors were tested. We observed that the low affinity ligand failed to exhibit anticonvulsant properties while the two high affinity ligands significantly attenuated the seizures. Continuous NPFF1 receptor agonist administration also inhibited limbic seizures whereas bolus administration of the NPFF1 receptor agonist was without effect. This suggests that continuous agonist perfusion could result in NPFF1 receptor desensitization and mimic NPFF1 receptor antagonist administration. Our data unveil for the first time the involvement of the NPFF system in the management of limbic seizures.

  1. Targeting Androgen Receptor in Breast Cancer: Enzalutamide as a Novel Breast Cancer Therapeutic

    Science.gov (United States)

    2016-09-01

    Speakers with Thea Tilsty “Targeting Androgen Receptors in a Subset of Triple Negative Breast Cancers.” May 2015 Bayer Scientific Advisory Board...Speakers with Thea Tilsty “Targeting Androgen Receptors in a Subset of Triple Negative Breast Cancers.” May 2015 Bayer Scientific Advisory Board...2218-28. 5. Panet- Raymond V, Gottlieb B, Beitel LK, Pinsky L, Trifiro MA. Interactions between androgen and estrogen receptors and the effects on

  2. Adenosine A2A receptor antagonists exert motor and neuroprotective effects by distinct cellular mechanisms

    OpenAIRE

    Yu, Liqun; Shen, Hai-Ying; Coelho, Joana E.; Araújo, Inês M.; HUANG, QING-YUAN; Day, Yuan-Ji; Rebola, Nelson; Canas, Paula M.; Rapp, Erica Kirsten; Ferrara, Jarrod; Taylor, Darcie; Müller, Christa E.; Linden, Joel; Cunha, Rodrigo A.; Chen, Jiang-Fan

    2008-01-01

    To investigate whether the motor and neuroprotective effects of adenosine A2A receptor (A2AR) antagonists are mediated by distinct cell types in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) model of Parkinson's disease.We used the forebrain A2AR knock-out mice coupled with flow cytometric analyses and intracerebroventricular injection to determine the contribution of A2ARs in forebrain neurons and glial cells to A2AR antagonist-mediated motor and neuroprotective effects.The selecti...

  3. Prolonged signaling at the parathyroid hormone receptor by peptide ligands targeted to a specific receptor conformation.

    Science.gov (United States)

    Okazaki, Makoto; Ferrandon, Sebastien; Vilardaga, Jean-Pierre; Bouxsein, Mary L; Potts, John T; Gardella, Thomas J

    2008-10-28

    The parathyroid hormone receptor (PTHR) is a class B G protein-coupled receptor that plays critical roles in bone and mineral ion metabolism. Ligand binding to the PTHR involves interactions to both the amino-terminal extracellular (N) domain, and transmembrane/extracellular loop, or juxtamembrane (J) regions of the receptor. Recently, we found that PTH(1-34), but not PTH-related protein, PTHrP(1-36), or M-PTH(1-14) (M = Ala/Aib(1),Aib(3),Gln(10),Har(11),Ala(12),Trp(14),Arg(19)), binds to the PTHR in a largely GTPgammaS-resistant fashion, suggesting selective binding to a novel, high-affinity conformation (R(0)), distinct from the GTPgammaS-sensitive conformation (RG). We examined the effects in vitro and in vivo of introducing the M substitutions, which enhance interaction to the J domain, into PTH analogs extended C-terminally to incorporate residues involved in the N domain interaction. As compared with PTH(1-34), M-PTH(1-28) and M-PTH(1-34) bound to R(0) with higher affinity, produced more sustained cAMP responses in cells, formed more stable complexes with the PTHR in FRET and subcellular localization assays, and induced more prolonged calcemic and phosphate responses in mice. Moreover, after 2 weeks of daily injection in mice, M-PTH(1-34) induced larger increases in trabecular bone volume and greater increases in cortical bone turnover, than did PTH(1-34). Thus, the putative R(0) PTHR conformation can form highly stable complexes with certain PTH ligand analogs and thereby mediate surprisingly prolonged signaling responses in bone and/or kidney PTH target cells. Controlling, via ligand analog design, the selectivity with which a PTH ligand binds to R(0), versus RG, may be a strategy for optimizing signaling duration time, and hence therapeutic efficacy, of PTHR agonist ligands.

  4. Adenosine activates brown adipose tissue and recruits beige adipocytes via A2A receptors

    DEFF Research Database (Denmark)

    Gnad, Thorsten; Scheibler, Saskia; von Kügelgen, Ivar

    2014-01-01

    hamster or rat. However, the role of adenosine in human BAT is unknown. Here we show that adenosine activates human and murine brown adipocytes at low nanomolar concentrations. Adenosine is released in BAT during stimulation of sympathetic nerves as well as from brown adipocytes. The adenosine A2A...... of A2A receptors or injection of lentiviral vectors expressing the A2A receptor into white fat induces brown-like cells-so-called beige adipocytes. Importantly, mice fed a high-fat diet and treated with an A2A agonist are leaner with improved glucose tolerance. Taken together, our results demonstrate...... that adenosine-A2A signalling plays an unexpected physiological role in sympathetic BAT activation and protects mice from diet-induced obesity. Those findings reveal new possibilities for developing novel obesity therapies....

  5. AT2 Receptors Targeting Cardiac Protection Post-Myocardial Infarction

    DEFF Research Database (Denmark)

    Kaschina, Elena; Lauer, Dilyara; Schmerler, Patrick

    2014-01-01

    The angiotensin AT2-receptor mediates tissue protective actions. Its regenerative potential has been tested in multiple disease models including models of myocardial infarction. These studies used different experimental approaches in order to detect AT2-receptor-related effects such as AT2-receptor...... is preserved over periods of up to four months. Depending on the experimental protocol, the AT2R also attenuates post-MI left ventricular remodeling or protects the heart from early left ventricular thinning and rupture. In combination with AT1-receptor blockade or deficiency, post-MI cardiac hypertrophy...... is reduced. This article reviews studies on the role of the AT2-receptor in myocardial infarction with an emphasis on the most recent data obtained in studies using AT2-receptor agonists....

  6. Adenosine A(2A receptor up-regulates retinal wave frequency via starburst amacrine cells in the developing rat retina.

    Directory of Open Access Journals (Sweden)

    Pin-Chien Huang

    Full Text Available BACKGROUND: Developing retinas display retinal waves, the patterned spontaneous activity essential for circuit refinement. During the first postnatal week in rodents, retinal waves are mediated by synaptic transmission between starburst amacrine cells (SACs and retinal ganglion cells (RGCs. The neuromodulator adenosine is essential for the generation of retinal waves. However, the cellular basis underlying adenosine's regulation of retinal waves remains elusive. Here, we investigated whether and how the adenosine A(2A receptor (A(2AR regulates retinal waves and whether A(2AR regulation of retinal waves acts via presynaptic SACs. METHODOLOGY/PRINCIPAL FINDINGS: We showed that A(2AR was expressed in the inner plexiform layer and ganglion cell layer of the developing rat retina. Knockdown of A(2AR decreased the frequency of spontaneous Ca²⁺ transients, suggesting that endogenous A(2AR may up-regulate wave frequency. To investigate whether A(2AR acts via presynaptic SACs, we targeted gene expression to SACs by the metabotropic glutamate receptor type II promoter. Ca²⁺ transient frequency was increased by expressing wild-type A(2AR (A2AR-WT in SACs, suggesting that A(2AR may up-regulate retinal waves via presynaptic SACs. Subsequent patch-clamp recordings on RGCs revealed that presynaptic A(2AR-WT increased the frequency of wave-associated postsynaptic currents (PSCs or depolarizations compared to the control, without changing the RGC's excitability, membrane potentials, or PSC charge. These findings suggest that presynaptic A(2AR may not affect the membrane properties of postsynaptic RGCs. In contrast, by expressing the C-terminal truncated A(2AR mutant (A(2AR-ΔC in SACs, the wave frequency was reduced compared to the A(2AR-WT, but was similar to the control, suggesting that the full-length A(2AR in SACs is required for A(2AR up-regulation of retinal waves. CONCLUSIONS/SIGNIFICANCE: A(2AR up-regulates the frequency of retinal waves via

  7. Inhibitory Mechanism of an Allosteric Antibody Targeting the Glucagon Receptor*

    OpenAIRE

    Mukund, Susmith; Shang, Yonglei; Clarke, Holly J.; Madjidi, Azadeh; Jacob E Corn; Kates, Lance; Kolumam, Ganesh; Chiang, Vicky; Luis, Elizabeth; Murray, Jeremy; Zhang, Yingnan; Hötzel, Isidro; Koth, Christopher M.; Allan, Bernard B.

    2013-01-01

    Elevated glucagon levels and increased hepatic glucagon receptor (GCGR) signaling contribute to hyperglycemia in type 2 diabetes. We have identified a monoclonal antibody that inhibits GCGR, a class B G-protein coupled receptor (GPCR), through a unique allosteric mechanism. Receptor inhibition is mediated by the binding of this antibody to two distinct sites that lie outside of the glucagon binding cleft. One site consists of a patch of residues that are surface-exposed on the face of the ext...

  8. Role of the Phospholipase A2 Receptor in Liposome Drug Delivery in Prostate Cancer Cells

    Science.gov (United States)

    2015-01-01

    The M-type phospholipase A2 receptor (PLA2R1) is a member of the C-type lectin superfamily and can internalize secreted phospholipase A2 (sPLA2) via endocytosis in non-cancer cells. sPLA2 itself was recently shown to be overexpressed in prostate tumors and to be a possible mediator of metastasis; however, little is known about the expression of PLA2R1 or its function in prostate cancers. Thus, we examined PLA2R1 expression in primary prostate cells (PCS-440-010) and human prostate cancer cells (LNCaP, DU-145, and PC-3), and we determined the effect of PLA2R1 knockdown on cytotoxicity induced by free or liposome-encapsulated chemotherapeutics. Immunoblot analysis demonstrated that the expression of PLA2R1 was higher in prostate cancer cells compared to that in primary prostate cells. Knockdown of PLA2R1 expression in PC-3 cells using shRNA increased cell proliferation and did not affect the toxicity of cisplatin, doxorubicin (Dox), and docetaxel. In contrast, PLA2R1 knockdown increased the in vitro toxicity of Dox encapsulated in sPLA2 responsive liposomes (SPRL) and correlated with increased Dox and SPRL uptake. Knockdown of PLA2R1 also increased the expression of Group IIA and X sPLA2. These data show the novel findings that PLA2R1 is expressed in prostate cancer cells, that PLA2R1 expression alters cell proliferation, and that PLA2R1 modulates the behavior of liposome-based nanoparticles. Furthermore, these studies suggest that PLA2R1 may represent a novel molecular target for controlling tumor growth or modulating delivery of lipid-based nanomedicines. PMID:25189995

  9. Multiple Targeting Approaches on Histamine H3 Receptor Antagonists

    Directory of Open Access Journals (Sweden)

    Mohammad eKhanfar

    2016-05-01

    Full Text Available With the very recent market approval of pitolisant (Wakix®, the interest in clinical applications of novel multifunctional histamine H3 receptor antagonists has clearly increased. Since histamine H3 receptor antagonists in clinical development have been tested for a variety of different indications, the combination of pharmacological properties in one molecule for improved pharmacological effects and reduced unwanted side-effects is rationally based on the increasing knowledge on the complex neurotransmitter regulations. The polypharmacological approaches on histamine H3 receptor antagonists on different G-protein coupled receptors, transporters, enzymes as well as on NO-signaling mechanism are described, supported with some lead structures.

  10. Multiple Targeting Approaches on Histamine H3 Receptor Antagonists.

    Science.gov (United States)

    Khanfar, Mohammad A; Affini, Anna; Lutsenko, Kiril; Nikolic, Katarina; Butini, Stefania; Stark, Holger

    2016-01-01

    With the very recent market approval of pitolisant (Wakix®), the interest in clinical applications of novel multifunctional histamine H3 receptor antagonists has clearly increased. Since histamine H3 receptor antagonists in clinical development have been tested for a variety of different indications, the combination of pharmacological properties in one molecule for improved pharmacological effects and reduced unwanted side-effects is rationally based on the increasing knowledge on the complex neurotransmitter regulations. The polypharmacological approaches on histamine H3 receptor antagonists on different G-protein coupled receptors, transporters, enzymes as well as on NO-signaling mechanism are described, supported with some lead structures.

  11. Orphan nuclear receptor NR4A2 inhibits hepatic stellate cell proliferation through MAPK pathway in liver fibrosis.

    Science.gov (United States)

    Chen, Pengguo; Li, Jie; Huo, Yan; Lu, Jin; Wan, Lili; Li, Bin; Gan, Run; Guo, Cheng

    2015-01-01

    Hepatic stellate cells (HSCs) play a crucial role in liver fibrosis, which is a pathological process characterized by extracellular matrix accumulation. NR4A2 is a nuclear receptor belonging to the NR4A subfamily and vital in regulating cell growth, metabolism, inflammation and other biological functions. However, its role in HSCs is unclear. We analyzed NR4A2 expression in fibrotic liver and stimulated HSCs compared with control group and studied the influence on cell proliferation, cell cycle, cell apoptosis and MAPK pathway after NR4A2 knockdown. NR4A2 expression was examined by real-time polymerase chain reaction, Western blotting, immunohistochemistry and immunofluorescence analyses. NR4A2 expression was significantly lower in fibrotic liver tissues and PDGF BB or TGF-β stimulated HSCs compared with control group. After NR4A2 knockdown α-smooth muscle actin and Col1 expression increased. In addition, NR4A2 silencing led to the promotion of cell proliferation, increase of cell percentage in S phase and reduced phosphorylation of ERK1/2, P38 and JNK in HSCs. These results indicate that NR4A2 can inhibit HSC proliferation through MAPK pathway and decrease extracellular matrix in liver fibrogenesis. NR4A2 may be a promising therapeutic target for liver fibrosis.

  12. Adenosine A2A receptor blockade or deletion diminishes fibrocyte accumulation in the skin in a murine model of scleroderma, bleomycin-induced fibrosis.

    Science.gov (United States)

    Katebi, Majid; Fernandez, Patricia; Chan, Edwin S L; Cronstein, Bruce N

    2008-10-01

    Peripheral blood fibrocytes are a newly identified circulating leukocyte subpopulation that migrates into injured tissue where it may display fibroblast-like properties and participate in wound healing and fibrosis of skin and other organs. Previous studies in our lab demonstrated that A(2A) receptor-deficient and A(2A) antagonist-treated mice were protected from developing bleomycin-induced dermal fibrosis, thus the aim of this study was to determine whether the adenosine A(2A) receptor regulates recruitment of fibrocytes to the dermis in this bleomycin-induced model of dermal fibrosis. Sections of skin from normal mice and bleomycin-treated wild type, A(2A) knockout and A(2A) antagonist-treated mice were stained for Procollagen alpha2 Type I and CD34 and the double stained cells, fibrocytes, were counted in the tissue sections. There were more fibrocytes in the dermis of bleomycin-treated mice than normal mice and the increase was abrogated by deletion or blockade of adenosine A(2A) receptors. Because fibrocytes play a central role in tissue fibrosis these results suggest that diminished adenosine A(2A) receptor-mediated recruitment of fibrocytes into tissue may play a role in the pathogenesis of fibrosing diseases of the skin. Moreover, these results provide further evidence that adenosine A(2A) receptors may represent a new target for the treatment of such fibrosing diseases as scleroderma or nephrogenic fibrosing dermopathy.

  13. [Metabotropic glutamate receptors as targets for new drug development].

    Science.gov (United States)

    Arkhipov, V I; Kapralova, M V

    2011-01-01

    The review is devoted to experimental investigations of metabotropic glutamate receptors and the properties of drugs (ligands) belonging to agonists, antagonists, and modulators of the activity of these receptors. Possibilities of the treatment of neurodegenerative disorders, cognitive disturbances in schizophrenia patients, and narcotic dependency by using drugs of this class are considered.

  14. Nuclear receptors as drug targets for metabolic disease

    NARCIS (Netherlands)

    Schulman, Ira G.

    2010-01-01

    Nuclear hormone receptors comprise a superfamily of ligand-activated transcription factors that control development, differentiation, and homeostasis. Over the last 15 years a growing number of nuclear receptors have been identified that coordinate genetic networks regulating lipid metabolism and en

  15. Platelet P2 receptors: from curiosity to clinical targets.

    Science.gov (United States)

    Cusack, N J; Hourani, S M

    2000-07-01

    Adenosine 5'-diphosphate (ADP) is a paracrine mediator that activates human blood platelets, causing them to become adhesive and thereby contributing to their role in hemostasis. The actions of ADP were initially thought to be mediated by a unique ADP receptor termed P2(T) found only on platelets and antagonized by ATP, but it appears that at least two P2Y receptor subtypes are involved, a P2Y(1) receptor linked in some way to control of intracellular-free calcium levels and another P2Y receptor linked via an inhibitory G protein to adenylate cyclase. In addition, the presence of excitatory P2X(1) receptors that mediate the influx of monovalent and divalent cations in response to both ADP and ATP has been demonstrated. The precise contribution that each of these P2 receptors make to the overall phenomena associated with platelet aggregation, adhesion and hemostasis is yet to be defined. Antithrombotic agents that interfere with the actions of ADP are marketed, and P2 receptor antagonists are entering clinical trials for acute treatments of thrombosis. This review seeks to summarize the present state of knowledge of platelet P2 receptor pharmacology and therapeutics.

  16. Nuclear receptors as drug targets for metabolic disease

    NARCIS (Netherlands)

    Schulman, Ira G.

    2010-01-01

    Nuclear hormone receptors comprise a superfamily of ligand-activated transcription factors that control development, differentiation, and homeostasis. Over the last 15 years a growing number of nuclear receptors have been identified that coordinate genetic networks regulating lipid metabolism and en

  17. Neurobeachin Regulates Glutamate- and GABA-Receptor Targeting to Synapses via Distinct Pathways.

    Science.gov (United States)

    Farzana, F; Zalm, R; Chen, N; Li, K W; Grant, Seth G N; Smit, A B; Toonen, R F; Verhage, M

    2016-05-01

    Neurotransmission and synaptic strength depend on expression of post-synaptic receptors on the cell surface. Post-translational modification of receptors, trafficking to the synapse through the secretory pathway, and subsequent insertion into the synapse involves interaction of the receptor with A-kinase anchor proteins (AKAPs) and scaffolding proteins. Neurobeachin (Nbea), a brain specific AKAP, is required for synaptic surface expression of both glutamate and GABA receptors. Here, we investigated the role of Nbea-dependent targeting of postsynaptic receptors by studying Nbea interaction with synapse-associated protein 102 (SAP102/Dlg3) and protein kinase A subunit II (PKA II). A Nbea mutant lacking the PKA binding domain showed a similar distribution as wild-type Nbea in Nbea null neurons and partially restored GABA receptor surface expression. To understand the relevance of Nbea interaction with SAP102, we analysed SAP102 null mutant mice. Nbea levels were reduced by ~80% in SAP102 null mice, but glutamatergic receptor expression was normal. A single-point mutation in the pleckstrin homology domain of Nbea (E2218R) resulted in loss of binding with SAP102. When expressed in Nbea null neurons, this mutant fully restored GABA receptor surface expression, but not glutamate receptor expression. Our results suggest that the PKA-binding domain is not essential for Nbea's role in receptor targeting and that Nbea targets glutamate and GABA receptors to the synapse via distinct molecular pathways by interacting with specific effector proteins.

  18. Receptor binding peptides for target-selective delivery of nanoparticles encapsulated drugs

    Directory of Open Access Journals (Sweden)

    Accardo A

    2014-03-01

    Full Text Available Antonella Accardo,1 Luigi Aloj,2 Michela Aurilio,2 Giancarlo Morelli,1 Diego Tesauro11Centro interuniversitario di Ricerca sui Peptidi Bioattivi (CIRPeB, Department of Pharmacy and Istituto di Biostrutture e Bioimmagini - Consiglio Nazionale delle Ricerche (IBB CNR, University of Naples “Federico II”, 2Department of Nuclear Medicine, Istituto Nazionale per lo Studio e la Cura dei Tumori, Fondazione “G. Pascale”, Napoli, ItalyAbstract: Active targeting by means of drug encapsulated nanoparticles decorated with targeting bioactive moieties represents the next frontier in drug delivery; it reduces drug side effects and increases the therapeutic index. Peptides, based on their chemical and biological properties, could have a prevalent role to direct drug encapsulated nanoparticles, such as liposomes, micelles, or hard nanoparticles, toward the tumor tissues. A considerable number of molecular targets for peptides are either exclusively expressed or overexpressed on both cancer vasculature and cancer cells. They can be classified into three wide categories: integrins; growth factor receptors (GFRs; and G-protein coupled receptors (GPCRs. Therapeutic agents based on nanovectors decorated with peptides targeting membrane receptors belonging to the GPCR family overexpressed by cancer cells are reviewed in this article. The most studied targeting membrane receptors are considered: somatostatin receptors; cholecystokinin receptors; receptors associated with the Bombesin like peptides family; luteinizing hormone-releasing hormone receptors; and neurotensin receptors. Nanovectors of different sizes and shapes (micelles, liposomes, or hard nanoparticles loaded with doxorubicin or other cytotoxic drugs and externally functionalized with natural or synthetic peptides are able to target the overexpressed receptors and are described based on their formulation and in vitro and in vivo behaviors.Keywords: receptors binding peptides, drug delivery

  19. The serotonin 5-HT3 receptor: a novel neurodevelopmental target

    Directory of Open Access Journals (Sweden)

    Mareen eEngel

    2013-05-01

    Full Text Available Serotonin (5-HT, next to being an important neurotransmitter, recently gained attention as a key regulator of pre- and postnatal development in the mammalian central nervous system (CNS. Several receptors for 5-HT are expressed in the developing brain including a ligand-gated ion channel, the 5-HT3 receptor. Over the past years, evidence has been accumulating that 5-HT3 receptors are involved in the regulation of neurodevelopment by serotonin.Here, we review the spatial and temporal expression patterns of 5-HT3 receptors in the pre- and early postnatal rodent brain and its functional implications. First, 5-HT3 receptors are expressed on GABAergic interneurons in neocortex and limbic structures derived from the caudal ganglionic eminence. Mature inhibitory GABAergic interneurons fine-tune neuronal excitability and thus are crucial for the physiological function of the brain. Second, 5-HT3 receptors are expressed on specific glutamatergic neurons, Cajal-Retzius cells in the cortex and granule cells in the cerebellum, where they regulate morphology, positioning and connectivity of the local microcircuitry. Taken together, the 5-HT3 receptor emerges as a potential key-regulator of network formation and function in the CNS, which could have a major impact on our understanding of neurodevelopmental disorders in which 5-HT plays a role.

  20. NTS adenosine A2a receptors inhibit the cardiopulmonary chemoreflex control of regional sympathetic outputs via a GABAergic mechanism.

    Science.gov (United States)

    Minic, Zeljka; O'Leary, Donal S; Scislo, Tadeusz J

    2015-07-01

    Adenosine is a powerful central neuromodulator acting via opposing A1 (inhibitor) and A2a (activator) receptors. However, in the nucleus of the solitary tract (NTS), both adenosine receptor subtypes attenuate cardiopulmonary chemoreflex (CCR) sympathoinhibition of renal, adrenal, and lumbar sympathetic nerve activity and attenuate reflex decreases in arterial pressure and heart rate. Adenosine A1 receptors inhibit glutamatergic transmission in the CCR pathway, whereas adenosine A2a receptors most likely facilitate release of an unknown inhibitory neurotransmitter, which, in turn, inhibits the CCR. We hypothesized that adenosine A2a receptors inhibit the CCR via facilitation of GABA release in the NTS. In urethane-chloralose-anesthetized rats (n = 51), we compared regional sympathetic responses evoked by stimulation of the CCR with right atrial injections of the 5-HT3 receptor agonist phenylbiguanide (1-8 μg/kg) before and after selective stimulation of NTS adenosine A2a receptors [microinjections into the NTS of CGS-21680 (20 pmol/50 nl)] preceded by blockade of GABAA or GABAB receptors in the NTS [bicuculline (10 pmol/100 nl) or SCH-50911 (1 nmol/100 nl)]. Blockade of GABAA receptors virtually abolished adenosine A2a receptor-mediated inhibition of the CCR. GABAB receptors had much weaker but significant effects. These effects were similar for the different sympathetic outputs. We conclude that stimulation of NTS adenosine A2a receptors inhibits CCR-evoked hemodynamic and regional sympathetic reflex responses via a GABA-ergic mechanism.

  1. Cannabinoid Receptors: A Novel Target for Treating Prostate Cancer

    Science.gov (United States)

    2006-02-01

    prostate cancer cells than in normal prostate epithelial cells and treatment of LNCaP cells with WIN-55,212-2 (a mixed CB1 / CB2 agonist) resulted in...34 CBI receptor, and the "peripheral" CB2 receptor. Recently we have shown that expression levels of both cannabinoid receptors CB1 and CB2 are higher...in human prostate cancer cells than in normal prostate epithelial cells and treatment of LNCaP cells with WIN-55,212-2 (a mixed CB1 / CB2 agonist

  2. Caffeine promotes anti-tumor immune response during tumor initiation: Involvement of the adenosine A2A receptor.

    Science.gov (United States)

    Eini, Hadar; Frishman, Valeria; Yulzari, Robert; Kachko, Leonid; Lewis, Eli C; Chaimovitz, Cidio; Douvdevani, Amos

    2015-11-01

    Epidemiologic studies depict a negative correlation between caffeine consumption and incidence of tumors in humans. The main pharmacological effects of caffeine are mediated by antagonism of the adenosine receptor, A2AR. Here, we examine whether the targeting of A2AR by caffeine plays a role in anti-tumor immunity. In particular, the effects of caffeine are studied in wild-type and A2AR knockout (A2AR(-/-)) mice. Tumor induction was achieved using the carcinogen 3-methylcholanthrene (3-MCA). Alternatively, tumor cells, comprised of 3-MCA-induced transformed cells or B16 melanoma cells, were inoculated into animal footpads. Cytokine release was determined in a mixed lymphocyte tumor reaction (MLTR). According to our findings, caffeine-consuming mice (0.1% in water) developed tumors at a lower rate compared to water-consuming mice (14% vs. 53%, respectively, p=0.0286, n=15/group). Within the caffeine-consuming mice, tumor-free mice displayed signs of autoimmune alopecia and pronounced leukocyte recruitment intocarcinogen injection sites. Similarly, A2AR(-/-) mice exhibited reduced rates of 3-MCA-induced tumors. In tumor inoculation studies, caffeine treatment resulted in inhibition of tumor growth and elevation in proinflammatory cytokine release over water-consuming mice, as depicted by MLTR. Addition of the adenosine receptor agonist, NECA, to MLTR resulted in a sharp decrease in IFNγ levels; this was reversed by the highly selective A2AR antagonist, ZM241385. Thus, immune response modulation through either caffeine or genetic deletion of A2AR leads to a Th1 immune profile and suppression of carcinogen-induced tumorigenesis. Taken together, our data suggest that the use of pharmacologic A2AR antagonists may hold therapeutic potential in diminishing the rate of cancer development.

  3. Amylin receptor: a common pathophysiological target in Alzheimer’s Disease and Diabetes Mellitus

    Directory of Open Access Journals (Sweden)

    Wen eFu

    2013-08-01

    Full Text Available Amylin (islet amyloid polypeptide and amyloid beta protein (Abeta, which are deposited within pancreatic islets of diabetics and brains of Alzheimer’s patients respectively, share many biophysical and physiological properties. Emerging evidence indicates that the amylin receptor is a putative target receptor for the actions of human amylin and Abeta in the brain. The amylin receptor consists of the calcitonin receptor dimerized with a receptor activity-modifying protein and is widely distributed within central nervous system. Both amylin and Abeta directly activate this G protein-coupled receptor and trigger multiple common intracellular signal transduction pathways that can culminate in apoptotic cell death. Moreover, amylin receptor antagonists can block both the biological and neurotoxic effects of human amylin and Abeta. Amylin receptors thus appear to be involved in the pathophysiology of AD and diabetes, and could serve as a molecular link between the two conditions that are associated epidemiologically.

  4. Positron emission tomography evaluation of somatostatin receptor targeted (64)Cu-TATE-liposomes in a human neuroendocrine carcinoma mouse model

    DEFF Research Database (Denmark)

    Petersen, Anncatrine Luisa; Binderup, Tina; Jølck, Rasmus Irming

    2012-01-01

    Targeted therapeutic and diagnostic nanocarriers functionalized with antibodies, peptides or other targeting ligands that recognize over-expressed receptors or antigens on tumor cells have potential in the diagnosis and therapy of cancer. Somatostatin receptors (SSTRs) are over-expressed in a var......Targeted therapeutic and diagnostic nanocarriers functionalized with antibodies, peptides or other targeting ligands that recognize over-expressed receptors or antigens on tumor cells have potential in the diagnosis and therapy of cancer. Somatostatin receptors (SSTRs) are over...

  5. Overexpression of adenosine A2A receptors in rats: effects on depression, locomotion and anxiety

    Directory of Open Access Journals (Sweden)

    Joana E Coelho

    2014-06-01

    Full Text Available Adenosine A2A receptors (A2AR are a sub-type of receptors enriched in basal ganglia, activated by the neuromodulator adenosine, which interact with dopamine D2 receptors. Although this reciprocal antagonistic interaction is well established in motor function, the outcome in dopamine-related behaviors remains uncertain, in particular in depression and anxiety. We have demonstrated an upsurge of A2AR associated to aging and chronic stress. Furthermore, Alzheimer’s disease patients present A2AR accumulation in cortical areas together with depressive signs. We now tested the impact of overexpressing A2AR in forebrain neurons on dopamine related behavior, namely depression. Adult male rats overexpressing human A2AR under the control of CaMKII promoter [Tg(CaMKII-hA2AR] and aged-matched wild-types (WT of the same strain (Sprague-Dawley were studied. The forced swimming test (FST, sucrose preference test (SPT and the open-field test (OFT were performed to evaluate behavioral despair, anhedonia, locomotion and anxiety. Tg(CaMKII-hA2AR animals spent more time floating and less time swimming in the FST and presented a decreased sucrose preference at 48h in the SPT. They also covered higher distances in the OFT and spent more time in the central zone than the WT. The results indicate that Tg(CaMKII-hA2AR rats exhibit depressive-like behavior, hyperlocomotion and altered exploratory behavior. This A2AR overexpression may explain the depressive signs found in aging, chronic stress and Alzheimer’s disease.

  6. Enhanced antitumor activity of cabazitaxel targeting CD44+ receptor ...

    African Journals Online (AJOL)

    prolonged circulation and slow release of the drug, as well as internalization of the nanocarrier into cancer cells. ... delivery of the anticancer drug via the CD44 receptor. ..... clinical pharmacology of the taxanes docetaxel and paclitaxel--a ...

  7. Multiple Targeting Approaches on Histamine H3 Receptor Antagonists

    OpenAIRE

    Mohammad eKhanfar; Anna eAffini; Kiril eLutsenko; Katarina eNikolic; Stefania eButini; Holger eStark

    2016-01-01

    With the very recent market approval of pitolisant (Wakix®), the interest in clinical applications of novel multifunctional histamine H3 receptor antagonists has clearly increased. Since histamine H3 receptor antagonists in clinical development have been tested for a variety of different indications, the combination of pharmacological properties in one molecule for improved pharmacological effects and reduced unwanted side-effects is rationally based on the increasing knowledge on the complex...

  8. Targeting Prostate Cancer with Bifunctional Modulators of the Androgen Receptor

    Science.gov (United States)

    2013-10-01

    surface results in the recruitment of different native binding partners. Although a powerful strategy, it has already been found that mutation of...GR response element while preserving ligand-mediated repression of NFkB . By providing novel ways for the receptor to engage specific coregulators...canonical GR 15 response element while preserving ligand-mediated repression of NFkB . By providing novel ways for the 16 receptor to engage specific

  9. Aberrant methylation of the M-type phospholipase A2 receptor gene in leukemic cells

    Directory of Open Access Journals (Sweden)

    Menschikowski Mario

    2012-12-01

    Full Text Available Abstract Background The M-type phospholipase A2 receptor (PLA2R1 plays a crucial role in several signaling pathways and may act as tumor-suppressor. This study examined the expression and methylation of the PLA2R1 gene in Jurkat and U937 leukemic cell lines and its methylation in patients with myelodysplastic syndrome (MDS or acute leukemia. Methods Sites of methylation of the PLA2R1 locus were identified by sequencing bisulfite-modified DNA fragments. Methylation specific-high resolution melting (MS-HRM analysis was then carried out to quantify PLA2R1 methylation at 5`-CpG sites identified with differences in methylation between healthy control subjects and leukemic patients using sequencing of bisulfite-modified genomic DNA. Results Expression of PLA2R1 was found to be completely down-regulated in Jurkat and U937 cells, accompanied by complete methylation of PLA2R1 promoter and down-stream regions; PLA2R1 was re-expressed after exposure of cells to 5-aza-2´-deoxycytidine. MS-HRM analysis of the PLA2R1 locus in patients with different types of leukemia indicated an average methylation of 28.9% ± 17.8%, compared to less than 9% in control subjects. In MDS patients the extent of PLA2R1 methylation significantly increased with disease risk. Furthermore, measurements of PLA2R1 methylation appeared useful for predicting responsiveness to the methyltransferase inhibitor, azacitidine, as a pre-emptive treatment to avoid hematological relapse in patients with high-risk MDS or acute myeloid leukemia. Conclusions The study shows for the first time that PLA2R1 gene sequences are a target of hypermethylation in leukemia, which may have pathophysiological relevance for disease evolution in MDS and leukemogenesis.

  10. Phospholipase A2 receptor autoantibodies and clinical outcome in patients with primary membranous nephropathy.

    Science.gov (United States)

    Hoxha, Elion; Thiele, Ina; Zahner, Gunther; Panzer, Ulf; Harendza, Sigrid; Stahl, Rolf A K

    2014-06-01

    Membranous nephropathy (MN) is the most common cause of nephrotic syndrome in adults, with an uncertain clinical outcome. The characterization of the phospholipase A2 receptor (PLA2R) as the major target antigen in primary MN and the detection of circulating autoantibodies in these patients is a major advance in understanding this disease. To test whether PLA2R antibody levels reflect disease activity or clinical outcome, we performed a prospective multicenter study of 133 adult patients with primary MN and detectable serum PLA2R antibodies who had not received immunosuppressive therapy. Patients were followed ≤24 months. PLA2R antibody levels associated with clinical disease activity (proteinuria) in patients with immunosuppressive therapy (n=101) or supportive care (n=32). Within 3 months, immunosuppressive therapy led to a sustained 81% reduction in PLA2R antibody levels paralleled by a 39% reduction in proteinuria. Patients who experienced remission of proteinuria after 12 months had significantly lower PLA2R antibody levels at the time of study inclusion compared with patients with no remission. Patients with high PLA2R antibody levels achieved remission of proteinuria significantly later than patients with low PLA2R antibody levels. PLA2R antibody levels fell over time in patients with spontaneous remission but remained elevated in patients who did not show a reduction in proteinuria. Multivariable Cox regression analysis confirmed PLA2R antibody level as an independent risk factor for not achieving remission of proteinuria. We conclude that a decrease in PLA2R antibody level is associated with a decrease of proteinuria in patients with primary MN.

  11. DMPD: Toll-like receptors: novel pharmacological targets for the treatment ofneurological diseases. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 17974478 Toll-like receptors: novel pharmacological targets for the treatment ofneu...png) (.svg) (.html) (.csml) Show Toll-like receptors: novel pharmacological targets for the treatment ofneur...ological diseases. PubmedID 17974478 Title Toll-like receptors: novel pharmacological targets for the trea...tment ofneurological diseases. Authors Marsh BJ, Stenzel-Poore MP. Publication Curr

  12. Revolution in GPCR signalling: opioid receptor heteromers as novel therapeutic targets: IUPHAR review 10.

    Science.gov (United States)

    Fujita, Wakako; Gomes, Ivone; Devi, Lakshmi A

    2014-09-01

    GPCRs can interact with each other to form homomers or heteromers. Homomers involve interactions with the same receptor type while heteromers involve interactions between two different GPCRs. These receptor-receptor interactions modulate not only the binding but also the signalling and trafficking properties of individual receptors. Opioid receptor heteromerization has been extensively investigated with the objective of identifying novel therapeutic targets that are as potent as morphine but without the side effects associated with chronic morphine use. In this context, studies have described heteromerization between the different types of opioid receptors and between opioid receptors and a wide range of GPCRs including adrenoceptors, cannabinoid, 5-HT, metabotropic glutamate and sensory neuron-specific receptors. Recent advances in the field involving the generation of heteromer-specific reagents (antibodies or ligands) or of membrane-permeable peptides that disrupt the heteromer interaction are helping to elucidate the physiological role of opioid receptor heteromers and the contribution of the partner receptor to the side effects associated with opioid use. For example, studies using membrane-permeable peptides targeting the heteromer interface have implicated μ and δ receptor heteromers in the development of tolerance to morphine, and heteromers of μ and gastrin-releasing peptide receptors in morphine-induced itch. In addition, a number of ligands that selectively target opioid receptor heteromers exhibit potent antinociception with a decrease in the side effects commonly associated with morphine use. In this review, we summarize the latest findings regarding the biological and functional characteristics of opioid receptor heteromers both in vitro and in vivo.

  13. Antagonists of the human A(2A) receptor. Part 6: Further optimization of pyrimidine-4-carboxamides.

    Science.gov (United States)

    Gillespie, Roger J; Bamford, Samantha J; Clay, Alex; Gaur, Suneel; Haymes, Tim; Jackson, Philip S; Jordan, Allan M; Klenke, Burkhard; Leonardi, Stefania; Liu, Jeanette; Mansell, Howard L; Ng, Sean; Saadi, Mona; Simmonite, Heather; Stratton, Gemma C; Todd, Richard S; Williamson, Douglas S; Yule, Ian A

    2009-09-15

    Antagonists of the human A(2A) receptor have been reported to have potential therapeutic benefit in the alleviation of the symptoms associated with neurodegenerative movement disorders such as Parkinson's disease. As part of our efforts to discover potent and selective antagonists of this receptor, we herein describe the detailed optimization and structure-activity relationships of a series of pyrimidine-4-carboxamides. These optimized derivatives display desirable physiochemical and pharmacokinetic profiles, which have led to promising oral activity in clinically relevant models of Parkinson's disease.

  14. Restriction of Receptor Movement Alters Cellular Response: Physical Force Sensing by EphA2

    Energy Technology Data Exchange (ETDEWEB)

    Salaita, Khalid; Nair, Pradeep M; Petit, Rebecca S; Neve, Richard M; Das, Debopriya; Gray, Joe W; Groves, Jay T

    2009-09-09

    Activation of the EphA2 receptor tyrosine kinase by ephrin-A1 ligands presented on apposed cell surfaces plays important roles in development and exhibits poorly understood functional alterations in cancer. We reconstituted this intermembrane signaling geometry between live EphA2-expressing human breast cancer cells and supported membranes displaying laterally mobile ephrin-A1. Receptor-ligand binding, clustering, and subsequent lateral transport within this junction were observed. EphA2 transport can be blocked by physical barriers nanofabricated onto the underlying substrate. This physical reorganization of EphA2 alters the cellular response to ephrin-A1, as observed by changes in cytoskeleton morphology and recruitment of a disintegrin and metalloprotease 10. Quantitative analysis of receptor-ligand spatial organization across a library of 26 mammary epithelial cell lines reveals characteristic differences that strongly correlate with invasion potential. These observations reveal a mechanism for spatio-mechanical regulation of EphA2 signaling pathways.

  15. Design and Characterization of Novel EphA2 Agonists for Targeted Delivery of Chemotherapy to Cancer Cells.

    Science.gov (United States)

    Wu, Bainan; Wang, Si; De, Surya K; Barile, Elisa; Quinn, Bridget A; Zharkikh, Irina; Purves, Angela; Stebbins, John L; Oshima, Robert G; Fisher, Paul B; Pellecchia, Maurizio

    2015-07-23

    The development of novel, targeted delivery agents for anti-cancer therapies requires the design and optimization of potent and selective tumor-targeting agents that are stable and amenable to conjugation with chemotherapeutic drugs. While short peptides represent potentially an excellent platform for these purposes, they often get degraded and are eliminated too rapidly in vivo. In this study, we used a combination of nuclear magnetic resonance-guided structure-activity relationships along with biochemical and cellular studies to derive a novel tumor-homing agent, named 123B9, targeting the EphA2 tyrosine kinase receptor ligand-binding domain. Conjugating 123B9 to the chemotherapeutic drug paclitaxel (PTX) via a stable linker results in an agent that is significantly more effective than the unconjugated drug in both a pancreatic cancer xenograft model and a melanoma lung colonization and metastases model. Hence, 123B9 could represent a promising strategy for the development of novel targeted therapies for cancer.

  16. A 2.5m long liquid hydrogen target for COMPASS

    CERN Document Server

    Bielert, E; Doshita, N; Geyer, R; Hashimoto, R; Horikawa, N; Ishimoto, S; Iwata, T; Kondo, K; Mallot, G K; Matsuda, H; Matsuda, T; Miyachi, Y; Nukazuka, G; Pirotte, O; Suzuki, H; Suzuki, S; Vullierme, B

    2014-01-01

    A 2.5 m long liquid hydrogen target has been developed for the COMPASS experiment at CERN to investigate the nucleon spin structure via the Deeply Virtual Compton Scattering (DVCS) process. To recognize exclusive DVCS events, produced photons and slow protons need to be detected. In order to do so, the material budget around the target has to be minimal. A 0.125 mm thick Kapton s target cell and a 1 mm thick carbon fi ber vacuum chamber with a Mylar s window have been constructed and tested. Finally, the target system was successfully employed during the DVCS pilot run in COMPASS at the end of 2012. The objective of this paper is to give a detailed description of this newly developed liquid hydrogen target apparatus

  17. Evidence that the EphA2 receptor exacerbates ischemic brain injury.

    Directory of Open Access Journals (Sweden)

    John Thundyil

    Full Text Available Ephrin (Eph signaling within the central nervous system is known to modulate axon guidance, synaptic plasticity, and to promote long-term potentiation. We investigated the potential involvement of EphA2 receptors in ischemic stroke-induced brain inflammation in a mouse model of focal stroke. Cerebral ischemia was induced in male C57Bl6/J wild-type (WT and EphA2-deficient (EphA2(-/- mice by middle cerebral artery occlusion (MCAO; 60 min, followed by reperfusion (24 or 72 h. Brain infarction was measured using triphenyltetrazolium chloride staining. Neurological deficit scores and brain infarct volumes were significantly less in EphA2(-/- mice compared with WT controls. This protection by EphA2 deletion was associated with a comparative decrease in brain edema, blood-brain barrier damage, MMP-9 expression and leukocyte infiltration, and higher expression levels of the tight junction protein, zona occludens-1. Moreover, EphA2(-/- brains had significantly lower levels of the pro-apoptotic proteins, cleaved caspase-3 and BAX, and higher levels of the anti-apoptotic protein, Bcl-2 as compared to WT group. We confirmed that isolated WT cortical neurons express the EphA2 receptor and its ligands (ephrin-A1-A3. Furthermore, expression of all four proteins was increased in WT primary cortical neurons following 24 h of glucose deprivation, and in the brains of WT mice following stroke. Glucose deprivation induced less cell death in primary neurons from EphA2(-/- compared with WT mice. In conclusion, our data provide the first evidence that the EphA2 receptor directly contributes to blood-brain barrier damage and neuronal death following ischemic stroke.

  18. NMDA-receptor trafficking and targeting: implications for synaptic transmission and plasticity.

    Science.gov (United States)

    Carroll, Reed C; Zukin, R Suzanne

    2002-11-01

    Dynamic regulation of synaptic efficacy is thought to play a crucial role in formation of neuronal connections and in experience-dependent modification of neural circuitry. The molecular and cellular mechanisms by which synaptic changes are triggered and expressed are the focus of intense interest. This articles reviews recent evidence that NMDA receptors undergo dynamically regulated targeting and trafficking, and that the physical transport of NMDA receptors in and out of the synaptic membrane contributes to several forms of long-lasting synaptic plasticity. The identification of targeting and internalization sequences in NMDA-receptor subunits has begun the unraveling of some mechanisms that underlie activity-dependent redistribution of NMDA receptors. Given that NMDA receptors are widely expressed throughout the CNS, regulation of NMDA-receptor trafficking provides a potentially important way to modulate efficacy of synaptic transmission.

  19. Pattern recognition receptors as potential therapeutic targets in inflammatory rheumatic disease.

    Science.gov (United States)

    Mullen, Lisa M; Chamberlain, Giselle; Sacre, Sandra

    2015-05-15

    The pattern recognition receptors of the innate immune system are part of the first line of defence against pathogens. However, they also have the ability to respond to danger signals that are frequently elevated during tissue damage and at sites of inflammation. Inadvertent activation of pattern recognition receptors has been proposed to contribute to the pathogenesis of many conditions including inflammatory rheumatic diseases. Prolonged inflammation most often results in pain and damage to tissues. In particular, the Toll-like receptors and nucleotide-binding oligomerisation domain-like receptors that form inflammasomes have been postulated as key contributors to the inflammation observed in rheumatoid arthritis, osteoarthritis, gout and systemic lupus erythematosus. As such, there is increasing interest in targeting these receptors for therapeutic treatment in the clinic. Here the role of pattern recognition receptors in the pathogenesis of these diseases is discussed, with an update on the development of interventions to modulate the activity of these potential therapeutic targets.

  20. New therapeutic strategies targeting D1-type dopamine receptors for neuropsychiatric disease

    Science.gov (United States)

    Kim, Young-Cho; Alberico, Stephanie L.; Emmons, Eric; Narayanan, Nandakumar S.

    2017-01-01

    The neurotransmitter dopamine acts via two major classes of receptors, D1-type and D2-type. D1 receptors are highly expressed in the striatum and can also be found in the cerebral cortex. Here we review the role of D1 dopamine signaling in two major domains: L-DOPA-induced dyskinesias in Parkinson’s disease and cognition in neuropsychiatric disorders. While there are many drugs targeting D2-type receptors, there are no drugs that specifically target D1 receptors. It has been difficult to use selective D1-receptor agonists for clinical applications due to issues with bioavailability, binding affinity, pharmacological kinetics, and side effects. We propose potential therapies that selectively modulate D1 dopamine signaling by targeting second messengers downstream of D1 receptors, allosteric modulators, or by making targeted modifications to D1-receptor machinery. The development of therapies specific to D1-receptor signaling could be a new frontier in the treatment of neurological and psychiatric disorders.

  1. Epidermal growth factor receptor-targeted antibody therapy - Mechanisms of action and modulators of therapeutic efficacy

    NARCIS (Netherlands)

    Lammerts van Bueren, Jeroen Jilles

    2008-01-01

    Cancer is an increasing disease in the world population, and in recent years there has been substantial interest in the development of novel therapeutic agents specifically targeting growth factor receptors on tumor cells. The epidermal growth factor receptor (EGFR) represents a tyrosine kinase cell

  2. The high-affinity immunoglobulin E receptor as pharmacological target.

    Science.gov (United States)

    Blank, Ulrich; Charles, Nicolas; Benhamou, Marc

    2016-05-05

    The high-affinity receptor for immunoglobulin E is expressed mainly on mast cells and basophils, but also on neutrophils, eosinophils, platelets, monocytes, Langerhans and dendritic cells, airway smooth muscle cells and some nerve cells. Its main function is, upon its engagement by IgE and specific antigen, to trigger a powerful defense against invading pathogens and a rapid neutralization of dangerous toxic substances introduced in the body. This powerful response could be wielded against tumors. But, when control over this receptor is lost, its unchecked activation can induce an array of diseases, some of which can lead to death. In this review we will summarize the pharmacological approaches and strategies that are currently used, or under study, to harness or wield activation of this receptor for therapeutic purposes.

  3. Adenosine A2A receptor hyperexpression in patients with severe SIRS after cardiopulmonary bypass.

    Science.gov (United States)

    Kerbaul, François; Bénard, Frédéric; Giorgi, Roch; Youlet, By; Carrega, Louis; Zouher, Ibrahim; Mercier, Laurence; Gérolami, Victoria; Bénas, Vincent; Blayac, Dorothée; Gariboldi, Vlad; Collart, Frédéric; Guieu, Régis

    2008-08-01

    Adenosine (ADO) is an endogenous nucleoside, which has been involved in blood pressure failure during severe systemic inflammatory response syndrome (severe SIRS) after cardiac surgery with cardiopulmonary bypass (CPB). Adenosine acts via its receptor subtypes, namely A1, A2A, A2B, or A3. Because A2A receptors are implicated in vascular tone, their expression might contribute to severe SIRS. We compared adenosine plasma levels (APLs) and A2A ADO receptor expression (ie, B, K, and mRNA amount) in patients with or without postoperative SIRS. : This was a prospective comparative observational study. Forty-four patients who underwent cardiac surgery involving CPB. Ten healthy subjects served as controls. Among the patients, 11 presented operative vasoplegia and postoperative SIRS (named complicated patients) and 33 were without vasoplegia or SIRS (named uncomplicated patients). Adenosine plasma levels, K, B, and mRNA amount (mean +/- SD) were measured on peripheral blood mononuclear cells. Adenosine plasma levels, B, and K were significantly higher in complicated patients than in uncomplicated patients (APLs: 2.7 +/- 1.0 vs 1.0 +/- 0.5 micromol l, P SIRS after CPB.

  4. Prenatal exposure to methylmercury alters development of adrenergic receptor binding sites in peripheral sympathetic target tissues

    Energy Technology Data Exchange (ETDEWEB)

    Slotkin, T.A.; Orband, L.; Cowdery, T.; Kavlock, R.J.; Bartolome, J.

    1987-01-01

    In order to assess the impact of prenatal exposure to methylmercury on sympathetic neurotransmission, effects on development of adrenergic receptor binding sites in peripheral tissues was evaluated. In the liver, methylmercury produced a dose-dependent increase in alpha/sub 1/, alpha/sub 2/, and beta-receptor binding of radioliganda throughout the first 5 weeks of postnatal life. Similarly, renal alpha-receptor subtypes showed increased binding capabilities, but binding to alpha-receptor sites was reduced. At least some of the changes in receptors appear to be of functional significance, as physiological reactivity to adrenergic stimulation is altered in the same directions in these two tissues. The actions of methylmercury displayed tissue specificity in that the same receptor populations were largely unaffected in other tissues (lung, heart). These results suggest that methylmercury exposure in utero alters adrenergic responses through targeted effects on postsynaptic receptor populations in specific tissues.

  5. Role of adenosine A1 and A2A receptors in the alcohol withdrawal syndrome.

    Science.gov (United States)

    Kaplan, G B; Bharmal, N H; Leite-Morris, K A; Adams, W R

    1999-10-01

    The role of adenosine receptor-mediated signaling was examined in the alcohol withdrawal syndrome. CD-1 mice received a liquid diet containing ethanol (6.7%, v/v) or a control liquid diet that were abruptly discontinued after 14 days of treatment. Mice consuming ethanol showed a progressive increase in signs of intoxication throughout the drinking period. Following abrupt discontinuation of ethanol diet, mice demonstrated reversible signs of handling-induced hyperexcitability that were maximal between 5-8 h. Withdrawing mice received treatment with adenosine receptor agonists at the onset of peak withdrawal (5.5 h) and withdrawal signs were blindly rated (during withdrawal hours 6 and 7). Adenosine A1-receptor agonist R-N6(phenylisopropyl)adenosine (0.15 and 0.3 mg/ kg) reduced withdrawal signs 0.5 and 1.5 h after drug administration in a dose-dependent fashion. Adenosine A2A-selective agonist 2-p-(2-carboxyethyl)phenylethyl-amino-5'-N-ethylcarboxamidoadenosine (0.3 mg/kg) reduced withdrawal signs at both time points. In ethanol-withdrawing mice, there were significant decreases in adenosine transporter sites in striatum without changes in cortex or cerebellum. In ethanol-withdrawing mice, there were no changes in adenosine A1 and A2A receptor concentrations in cortex, striatum, or cerebellum. There appears to be a role for adenosine A1 and A2A receptors in the treatment of the ethanol withdrawal syndrome. Published by Elsevier Science Inc.

  6. Evidence for homogeneity of thromboxane A2 receptor using structurally different antagonists.

    Science.gov (United States)

    Swayne, G T; Maguire, J; Dolan, J; Raval, P; Dane, G; Greener, M; Owen, D A

    1988-08-01

    Nine structurally dissimilar thromboxane antagonists (SQ 29548, ICI 185282, AH 23848, BM 13505 (Daltroban), BM 13177 (Sulotroban), SK&F 88046, L-636499, L-640035 and a Bayer compound SK&F 47821) were studied for activity as thromboxane A2 receptor antagonists. The assays used were inhibition of responses induced by the thromboxane mimetic, U46619, on human washed platelet aggregation, rabbit platelet aggregation, rabbit aortic strip contraction, anaesthetised guinea-pig bronchoconstriction, and a radio-labelled ligand (125I-PTA-OH) binding assay as a measure of affinity for the human platelet receptor. The results of the present study, with activities spanning at least four orders of magnitude along with statistically significant correlations (at least P less than 0.01), strongly suggests that between assays, antagonists and species a homogenous population of thromboxane A2 receptors exists. This finding is in contrast to those of a close series of 13-azapinane antagonists studied by other workers which have suggested receptor heterogeneity.

  7. The serotonin 5-HT3 receptor: a novel neurodevelopmental target.

    NARCIS (Netherlands)

    Engel, M.; Smidt, M.P.; van Hooft, J.A.

    2013-01-01

    Serotonin (5-hydroxytryptamine, 5-HT), next to being an important neurotransmitter, recently gained attention as a key-regulator of pre- and postnatal development in the mammalian central nervous system (CNS). Several receptors for 5-HT are expressed in the developing brain including a ligand-gated

  8. Receptor targeting of hemoglobin mediated by the haptoglobins

    DEFF Research Database (Denmark)

    Nielsen, Marianne Jensby; Moestrup, Søren Kragh

    2009-01-01

    Haptoglobin, the haptoglobin-hemoglobin receptor CD163, and the heme oxygenase-1 are proteins with a well-established function in the clearance and metabolism of "free" hemoglobin released during intravascular hemolysis. This scavenging system counteracts the potentially harmful oxidative and NO-...

  9. Meeting the EU recycling targets by introducing a 2-compartment bin to households

    DEFF Research Database (Denmark)

    Jensen, Morten Bang; Scheutz, Charlotte; Møller, Jacob

    A Danish municipality has introduced a 2-compartment bin in the waste collection scheme, this bin should increase recycling of dry household recyclables. An excessive waste sorting campaign was conducted and the efficiency of the bin assessed. The waste sorting campaign yielded a full waste...... composition with focus on the dry recyclables, and it was used to determine wheter the 2-compartment bin could fulfill the EU recycling targets for 2020. Only 2 of 4 calculation methods for meeting the EU targets were applicable and only one of these fulfilled the EU target. Eventhough the EU recycling...... targets can be fulfilled, there is still room for improvement (increase source separation), especially for hard plastic and metals....

  10. α2-containing GABAA receptors: A target for the development of novel treatment strategies for CNS disorders

    OpenAIRE

    2012-01-01

    GABAA receptors have important physiological functions, as revealed by pharmacological studies and experiments involving gene-targeted mouse models, and are the target of widely used drugs such as the benzodiazepines. In this review, we are summarizing current knowledge about the function of α2-containing GABAA receptors, a receptor subtype representing approximately 15–20% of all GABAA receptors. This receptor subtype mediates anxiolytic-like, reward-enhancing, and antihyperalgesic actions o...

  11. Targeting the Diuretic Hormone Receptor to Control the Cotton Leafworm, Spodoptera littoralis

    Science.gov (United States)

    Apone, Fabio; Ruggiero, Alessandra; Tortora, Assunta; Tito, Annalisa; Grimaldi, Maria Rosaria; Arciello, Stefania; Andrenacci, Davide; Lelio, Ilaria Di; Colucci, Gabriella

    2014-01-01

    The cotton leafworm, Spodoptera littoralis Boisduval (Lepidoptera: Noctuidae), is one of the most devastating pests of crops worldwide. Several types of treatments have been used against this pest, but many of them failed because of the rapid development of genetic resistance in the different insect populations. G protein coupled receptors have vital functions in most organisms, including insects; thus, they are appealing targets for species-specific pest control strategies. Among the insect G protein coupled receptors, the diuretic hormone receptors have several key roles in development and metabolism, but their importance in vivo and their potential role as targets of novel pest control strategies are largely unexplored. With the goal of using DHR genes as targets to control S. littoralis, we cloned a corticotropin-releasing factor-like binding receptor in this species and expressed the corresponding dsRNA in tobacco plants to knock down the receptor activity in vivo through RNA interference. We also expressed the receptor in mammalian cells to study its signaling pathways. The results indicate that this diuretic hormone receptor gene has vital roles in S. littoralis and represents an excellent molecular target to protect agriculturallyimportant plants from this pest. PMID:25368043

  12. Bypassing Protein Corona Issue on Active Targeting: Zwitterionic Coatings Dictate Specific Interactions of Targeting Moieties and Cell Receptors.

    Science.gov (United States)

    Safavi-Sohi, Reihaneh; Maghari, Shokoofeh; Raoufi, Mohammad; Jalali, Seyed Amir; Hajipour, Mohammad J; Ghassempour, Alireza; Mahmoudi, Morteza

    2016-09-07

    Surface functionalization strategies for targeting nanoparticles (NP) to specific organs, cells, or organelles, is the foundation for new applications of nanomedicine to drug delivery and biomedical imaging. Interaction of NPs with biological media leads to the formation of a biomolecular layer at the surface of NPs so-called as "protein corona". This corona layer can shield active molecules at the surface of NPs and cause mistargeting or unintended scavenging by the liver, kidney, or spleen. To overcome this corona issue, we have designed biotin-cysteine conjugated silica NPs (biotin was employed as a targeting molecule and cysteine was used as a zwitterionic ligand) to inhibit corona-induced mistargeting and thus significantly enhance the active targeting capability of NPs in complex biological media. To probe the targeting yield of our engineered NPs, we employed both modified silicon wafer substrates with streptavidin (i.e., biotin receptor) to simulate a target and a cell-based model platform using tumor cell lines that overexpress biotin receptors. In both cases, after incubation with human plasma (thus forming a protein corona), cellular uptake/substrate attachment of the targeted NPs with zwitterionic coatings were significantly higher than the same NPs without zwitterionic coating. Our results demonstrated that NPs with a zwitterionic surface can considerably facilitate targeting yield of NPs and provide a promising new type of nanocarriers in biological applications.

  13. Striatal pre- and postsynaptic profile of adenosine A(2A receptor antagonists.

    Directory of Open Access Journals (Sweden)

    Marco Orru

    Full Text Available Striatal adenosine A(2A receptors (A(2ARs are highly expressed in medium spiny neurons (MSNs of the indirect efferent pathway, where they heteromerize with dopamine D(2 receptors (D(2Rs. A(2ARs are also localized presynaptically in cortico-striatal glutamatergic terminals contacting MSNs of the direct efferent pathway, where they heteromerize with adenosine A(1 receptors (A(1Rs. It has been hypothesized that postsynaptic A(2AR antagonists should be useful in Parkinson's disease, while presynaptic A(2AR antagonists could be beneficial in dyskinetic disorders, such as Huntington's disease, obsessive-compulsive disorders and drug addiction. The aim or this work was to determine whether selective A(2AR antagonists may be subdivided according to a preferential pre- versus postsynaptic mechanism of action. The potency at blocking the motor output and striatal glutamate release induced by cortical electrical stimulation and the potency at inducing locomotor activation were used as in vivo measures of pre- and postsynaptic activities, respectively. SCH-442416 and KW-6002 showed a significant preferential pre- and postsynaptic profile, respectively, while the other tested compounds (MSX-2, SCH-420814, ZM-241385 and SCH-58261 showed no clear preference. Radioligand-binding experiments were performed in cells expressing A(2AR-D(2R and A(1R-A(2AR heteromers to determine possible differences in the affinity of these compounds for different A(2AR heteromers. Heteromerization played a key role in the presynaptic profile of SCH-442416, since it bound with much less affinity to A(2AR when co-expressed with D(2R than with A(1R. KW-6002 showed the best relative affinity for A(2AR co-expressed with D(2R than co-expressed with A(1R, which can at least partially explain the postsynaptic profile of this compound. Also, the in vitro pharmacological profile of MSX-2, SCH-420814, ZM-241385 and SCH-58261 was is in accordance with their mixed pre- and postsynaptic profile

  14. Expression of androgen receptor target genes in skeletal muscle

    OpenAIRE

    2014-01-01

    We aimed to determine the mechanisms of the anabolic actions of androgens in skeletal muscle by investigating potential androgen receptor (AR)-regulated genes in in vitro and in vivo models. The expression of the myogenic regulatory factor myogenin was significantly decreased in skeletal muscle from testosterone-treated orchidectomized male mice compared to control orchidectomized males, and was increased in muscle from male AR knockout mice that lacked DNA binding activity (ARΔZF2 ) versus w...

  15. Cannabinoid CB1 receptor-interacting proteins: novel targets for central nervous system drug discovery?

    Science.gov (United States)

    Smith, Tricia H; Sim-Selley, Laura J; Selley, Dana E

    2010-06-01

    The main pharmacological effects of marijuana, as well as synthetic and endogenous cannabinoids, are mediated through G-protein-coupled receptors (GPCRs), including CB(1) and CB(2) receptors. The CB(1) receptor is the major cannabinoid receptor in the central nervous system and has gained increasing interest as a target for drug discovery for treatment of nausea, cachexia, obesity, pain, spasticity, neurodegenerative diseases and mood and substance abuse disorders. Evidence has accumulated to suggest that CB(1) receptors, like other GPCRs, interact with and are regulated by several other proteins beyond the established role of heterotrimeric G-proteins. These proteins, which include the GPCR kinases, beta-arrestins, GPCR-associated sorting proteins, factor associated with neutral sphingomyelinase, other GPCRs (heterodimerization) and the novel cannabinoid receptor-interacting proteins: CRIP(1a/b), are thought to play important roles in the regulation of intracellular trafficking, desensitization, down-regulation, signal transduction and constitutive activity of CB(1) receptors. This review examines CB(1) receptor-interacting proteins, including heterotrimeric G-proteins, but with particular emphasis on non-G-protein entities, that might comprise the CB(1) receptosomal complex. The evidence for direct interaction with CB(1) receptors and potential functional roles of these interacting proteins is discussed, as are future directions and challenges in this field with an emphasis on the possibility of eventually targeting these proteins for drug discovery.

  16. Targeting C-type Lectin Receptors for Cancer Immunity

    Directory of Open Access Journals (Sweden)

    Huimin eYan

    2015-08-01

    Full Text Available C-type lectin receptors (CLRs are a large family of soluble and trans-membrane pattern recognition receptors that are widely and primarily expressed on myeloid cells. CLRs are important for cell-cell communication and host defense against pathogens through the recognition of specific carbohydrate structures. Similar to a family of Toll-like receptors (TLRs, CLRs signaling are involved in the various steps for initiation of innate immune responses and promote secretion of soluble factors such as cytokines and interferons, Moreover, CLRs contribute to endocytosis and antigen-presentation, thereby fine-tune adaptive immune responses. In addition, there may also be a direct activation of acquired immunity. On the other hand, glycans, such as mannose structures, Lewis-type antigens or GalNAc are components of tumor antigens and ligate CLRs, leading to immunoregulation. Therefore agonists or antagonists of CLRs signaling are potential therapeutic reagents for cancer immunotherapy. We aim to overview the current knowledge of CLRs signaling and the application of their ligands on tumor-associating immune response.

  17. Inhibitory mechanism of an allosteric antibody targeting the glucagon receptor.

    Science.gov (United States)

    Mukund, Susmith; Shang, Yonglei; Clarke, Holly J; Madjidi, Azadeh; Corn, Jacob E; Kates, Lance; Kolumam, Ganesh; Chiang, Vicky; Luis, Elizabeth; Murray, Jeremy; Zhang, Yingnan; Hötzel, Isidro; Koth, Christopher M; Allan, Bernard B

    2013-12-13

    Elevated glucagon levels and increased hepatic glucagon receptor (GCGR) signaling contribute to hyperglycemia in type 2 diabetes. We have identified a monoclonal antibody that inhibits GCGR, a class B G-protein coupled receptor (GPCR), through a unique allosteric mechanism. Receptor inhibition is mediated by the binding of this antibody to two distinct sites that lie outside of the glucagon binding cleft. One site consists of a patch of residues that are surface-exposed on the face of the extracellular domain (ECD) opposite the ligand-binding cleft, whereas the second binding site consists of residues in the αA helix of the ECD. A docking model suggests that the antibody does not occlude the ligand-binding cleft. We solved the crystal structure of GCGR ECD containing a naturally occurring G40S mutation and found a shift in the register of the αA helix that prevents antibody binding. We also found that alterations in the αA helix impact the normal function of GCGR. We present a model for the allosteric inhibition of GCGR by a monoclonal antibody that may form the basis for the development of allosteric modulators for the treatment of diabetes and other class B GPCR-related diseases.

  18. Parallel evolution of domesticated Caenorhabditis species targets pheromone receptor genes.

    Science.gov (United States)

    McGrath, Patrick T; Xu, Yifan; Ailion, Michael; Garrison, Jennifer L; Butcher, Rebecca A; Bargmann, Cornelia I

    2011-08-17

    Evolution can follow predictable genetic trajectories, indicating that discrete environmental shifts can select for reproducible genetic changes. Conspecific individuals are an important feature of an animal's environment, and a potential source of selective pressures. Here we show that adaptation of two Caenorhabditis species to growth at high density, a feature common to domestic environments, occurs by reproducible genetic changes to pheromone receptor genes. Chemical communication through pheromones that accumulate during high-density growth causes young nematode larvae to enter the long-lived but non-reproductive dauer stage. Two strains of Caenorhabditis elegans grown at high density have independently acquired multigenic resistance to pheromone-induced dauer formation. In each strain, resistance to the pheromone ascaroside C3 results from a deletion that disrupts the adjacent chemoreceptor genes serpentine receptor class g (srg)-36 and -37. Through misexpression experiments, we show that these genes encode redundant G-protein-coupled receptors for ascaroside C3. Multigenic resistance to dauer formation has also arisen in high-density cultures of a different nematode species, Caenorhabditis briggsae, resulting in part from deletion of an srg gene paralogous to srg-36 and srg-37. These results demonstrate rapid remodelling of the chemoreceptor repertoire as an adaptation to specific environments, and indicate that parallel changes to a common genetic substrate can affect life-history traits across species.

  19. Therapeutic targeting of epidermal growth factor receptor in human cancer: successes and limitations%Therapeutic targeting of epidermal growth factor receptor in humancancer: successes and limitations

    Institute of Scientific and Technical Information of China (English)

    Jill Wykosky; Tim Fenton; Frank Furnari; Webster K. Cavenee

    2011-01-01

    Epidermal growth factor receptor (EGFR) is one of the most commonly altered genes in human cancer by way of over-expression, amplification, and mutation. Targeted inhibition of EGFR activity suppresses signal transduction pathways which control tumor cell growth, proliferation, and resistance to apoptosis. Small molecule tyrosine kinase inhibitors and monoclonal antibodies are among the most common EGFR-targeting agents and have been used clinically for treating various malignancies. This review discusses the successes and challenges of targeting EGFR in human cancer. The genetic alterations of EGFR tend to occur more often in some solid tumors than others, as do the mechanisms of resistance to targeted inhibition. The clinical and basic science experiences with these agents thus far have important implications for the future of therapeutic targeting of EGFR.

  20. Ultraslow Water-Mediated Transmembrane Interactions Regulate the Activation of A2A Adenosine Receptor.

    Science.gov (United States)

    Lee, Yoonji; Kim, Songmi; Choi, Sun; Hyeon, Changbong

    2016-09-20

    Water molecules inside a G-protein coupled receptor (GPCR) have recently been spotlighted in a series of crystal structures. To decipher the dynamics and functional roles of internal water molecules in GPCR activity, we studied the A2A adenosine receptor using microsecond molecular-dynamics simulations. Our study finds that the amount of water flux across the transmembrane (TM) domain varies depending on the receptor state, and that the water molecules of the TM channel in the active state flow three times more slowly than those in the inactive state. Depending on the location in solvent-protein interface as well as the receptor state, the average residence time of water in each residue varies from ∼O(10(2)) ps to ∼O(10(2)) ns. Especially, water molecules, exhibiting ultraslow relaxation (∼O(10(2)) ns) in the active state, are found around the microswitch residues that are considered activity hotspots for GPCR function. A continuous allosteric network spanning the TM domain, arising from water-mediated contacts, is unique in the active state, underscoring the importance of slow water molecules in the activation of GPCRs. Copyright © 2016 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  1. Modification of the tetrodotoxin receptor in Electrophorus electricus by phospholipase A2.

    Science.gov (United States)

    Reed, J K

    1981-08-06

    The effects of phospholipase A2 treatment on the tetrodotoxin receptors in Electrophorus electricus was studied. (1) The binding of [3H]tetrodotoxin to electroplaque membranes was substantially reduced by treatment of the membranes with low concentrations of phospholipase A2 from a number of sources, including bee venom, Vipera russelli and Crotalus adamanteus and by beta-bungarotoxin. (2) Phospholipase A2 from bee venom and from C. adamanteus both caused extensive hydrolysis of electroplaque membrane phospholipids although the substrate specificity differed. Analysis of the phospholipid classes hydrolyzed revealed a striking correlation between loss of toxin binding and hydrolysis of phosphatidylethanolamine but not of phosphatidylserine. (3) The loss of toxin binding could be partially reversed by treatment of the membranes with bovine serum albumin, conditions which are known to remove hydrolysis products from the membrane. (4) Equilibrium binding studies on the effects of phospholipase A2 treatment of [3H]tetrodotoxin binding showed that the reduction reflected loss of binding sites and not a change in affinity. (5) These results are interpreted in terms of multiple equilibrium states of the tetrodotoxin-receptors with conformations determined by the phospholipid environment.

  2. Activation of NTS A2a adenosine receptors differentially resets baroreflex control of renal vs. adrenal sympathetic nerve activity.

    Science.gov (United States)

    Ichinose, Tomoko K; O'Leary, Donal S; Scislo, Tadeusz J

    2009-04-01

    The role of nucleus of solitary tract (NTS) A(2a) adenosine receptors in baroreflex mechanisms is controversial. Stimulation of these receptors releases glutamate within the NTS and elicits baroreflex-like decreases in mean arterial pressure (MAP), heart rate (HR), and renal sympathetic nerve activity (RSNA), whereas inhibition of these receptors attenuates HR baroreflex responses. In contrast, stimulation of NTS A(2a) adenosine receptors increases preganglionic adrenal sympathetic nerve activity (pre-ASNA), and the depressor and sympathoinhibitory responses are not markedly affected by sinoaortic denervation and blockade of NTS glutamatergic transmission. To elucidate the role of NTS A(2a) adenosine receptors in baroreflex function, we compared full baroreflex stimulus-response curves for HR, RSNA, and pre-ASNA (intravenous nitroprusside/phenylephrine) before and after bilateral NTS microinjections of selective adenosine A(2a) receptor agonist (CGS-21680; 2.0, 20 pmol/50 nl), selective A(2a) receptor antagonist (ZM-241385; 40 pmol/100 nl), and nonselective A(1) + A(2a) receptor antagonist (8-SPT; 1 nmol/100 nl) in urethane/alpha-chloralose anesthetized rats. Activation of A(2a) receptors decreased the range, upper plateau, and gain of baroreflex-response curves for RSNA, whereas these parameters all increased for pre-ASNA, consistent with direct effects of the agonist on regional sympathetic activity. However, no resetting of baroreflex-response curves along the MAP axis occurred despite the marked decreases in baseline MAP. The antagonists had no marked effects on baseline variables or baroreflex-response functions. We conclude that the activation of NTS A(2a) adenosine receptors differentially alters baroreflex control of HR, RSNA, and pre-ASNA mostly via non-baroreflex mechanism(s), and these receptors have virtually no tonic action on baroreflex control of these sympathetic outputs.

  3. A2B adenosine receptors stimulate IL-6 production in primary murine microglia through p38 MAPK kinase pathway.

    Science.gov (United States)

    Merighi, Stefania; Bencivenni, Serena; Vincenzi, Fabrizio; Varani, Katia; Borea, Pier Andrea; Gessi, Stefania

    2017-03-01

    The hallmark of neuroinflammation is the activation of microglia, the immunocompetent cells of the CNS, releasing a number of proinflammatory mediators implicated in the pathogenesis of neuronal diseases. Adenosine is an ubiquitous autacoid regulating several microglia functions through four receptor subtypes named A1, A2A, A2B and A3 (ARs), that represent good targets to suppress inflammation occurring in CNS. Here we investigated the potential role of ARs in the modulation of IL-6 secretion and cell proliferation in primary microglial cells. The A2BAR agonist 2-[[6-Amino-3,5-dicyano-4-[4-(cyclopropylmethoxy)phenyl]-2-pyridinyl]thio]-acetamide (BAY60-6583) stimulated IL-6 increase under normoxia and hypoxia, in a dose- and time-dependent way. In cells incubated with the blockers of phospholipase C (PLC), protein kinase C epsilon (PKC-ε) and PKC delta (PKC-δ) the IL-6 increase due to A2BAR activation was strongly reduced, whilst it was not affected by the inhibitor of adenylyl cyclase (AC). Investigation of cellular signalling involved in the A2BAR effect revealed that only the inhibitor of p38 mitogen activated protein kinase (MAPK) was able to block the agonist's effect on IL-6 secretion, whilst inhibitors of pERK1/2, JNK1/2 MAPKs and Akt were not. Stimulation of p38 by BAY60-6583 was A2BAR-dependent, through a pathway affecting PLC, PKC-ε and PKC-δ but not AC, in both normoxia and hypoxia. Finally, BAY60-6583 increased microglial cell proliferation involving A2BAR, PLC, PKC-ε, PKC-δ and p38 signalling. In conclusion, A2BARs activation increased IL-6 secretion and cell proliferation in murine primary microglial cells, through PLC, PKC-ε, PKC-δ and p38 pathways, thus suggesting their involvement in microglial activation and neuroinflammation.

  4. Receptor-mediated gene delivery using polyethylenimine (PEI)coupled with polypeptides targeting FGF receptors on cells surface

    Institute of Scientific and Technical Information of China (English)

    LI Da; WANG Qing-qing; TANG Gu-ping; HUANG Hong-liang; SHEN Fen-ping; LI Jing-zhong; YU Hai

    2006-01-01

    Objective: To construct a novel kind ofnonviral gene delivery vector based on polyethylenimine (PEI) conjugated with polypeptides derived from ligand FGF with high transfection efficiency and according to tumor targeting ability. Methods:The synthetic polypeptides CR16 for binding FGF receptors was conjugated to PEI and the characters of the polypeptides including DNA condensing and particle size were determined. Enhanced efficiency and the targeting specificity of the synthesized vector were investigated in vitro and in vivo. Results: The polypeptides were successfully coupled to PEI. The new vectors PEI-CR16 could efficiently condense pDNA into particles with around 200 nm diameter. The PEI-CR16/pDNA polyplexes showed significantly greater transgene activity than PEI/pDNA in FGF receptors positive tumor cells in vitro and in vivo gene transfer, while no difference was observed in FGF receptors negative tumor cells. The enhanced transfection efficiency of PEI-CR16 could be blocked by excess free polypeptides. Conclusion: The synthesized vector could improve the efficiency of gene transfer and targeting specificity in FGF receptors positive cells. The vector had good prospect for use in cancer gene therapy.

  5. MicroRNA Targets of Human Androgen Receptor

    Science.gov (United States)

    2013-05-01

    suggests that AR can be targeted by andro - miRs in CRPC adjuvant therapeutics (Sikand et al. 2011a; Sikand et al. 2011b) . It has also envisioned that...that p68 RNA helicase interacts with the Drosha enzymes, we had proposed that AR might be modifying the post-transcriptional processing of “ andro -miR...prevent the processing of “ Andro -miRs,” the miRNA which are targeting AR expression. One and only proposed specific aim and subaims of the study

  6. DNA intersegment transfer, how steroid receptors search for a target site.

    Science.gov (United States)

    Lieberman, B A; Nordeen, S K

    1997-01-10

    The mammalian nucleus contains 6 billion base pairs of DNA, encoding about 100,000 genes, yet in a given cell steroid hormones induce only a handful of genes. The logistical difficulties faced by steroid receptors or other transcription factors of sorting through this much genetic information is further increased by the density of nuclear DNA (approximately 10-50 mg/ml). Standard models propose that steroid receptors find target elements by repeated cycles of dissociation and reassociation until a high affinity site is found (cycling model) and/or by conducting a one-dimensional search along the DNA (sliding model). A third model proposes that steroid receptors search for target sites in the genome by DNA intersegment transfer. In this model, receptor dimers bind nonspecific DNA sequences and search for a target site by binding a second strand of DNA before dissociating from the first, in effect moving through the genome like Tarzan swinging from vine to vine. This model has the advantage that a high concentration of DNA favors, rather than hinders, the search. The intersegment transfer model predicts, in contrast to the cycling and sliding models, that the dissociation rate of receptor from DNA is highly dependent on DNA concentration. We have employed the purified DNA binding domain fragment from the rat glucocorticoid receptor to perform equilibrium and kinetic studies of the DNA dependence of receptor-DNA dissociation. We find receptor dissociation from DNA to be highly dependent on the concentration of DNA in solution, in agreement with the intersegment transfer model. We also find that this interaction is primarily electrostatic, because DNA-like polyanion chains (e.g. heparin and polyglutamate) can mediate the transfer. These studies provide evidence that direct DNA transfer aids the target site search conducted by steroid receptors in their role as inducible transcription factors.

  7. Melatonin receptors in diabetes: a potential new therapeutical target?

    Science.gov (United States)

    She, Meihua; Laudon, Moshe; Yin, Weidong

    2014-12-05

    Melatonin is synthesized and secreted mainly by the pineal gland in a circadian fashion, and it thus mediates endogenous circadian rhythms and influences other physiological functions. Both the G-protein coupled receptors MT1 (encoded by MTNR1A) and MT2 (encoded by MTNR1B) in mammals mediate the actions of melatonin. Evidence from in vivo and in vitro studies proved a key role of melatonin in the regulation of glucose metabolism and the pathogenesis of diabetes, as further confirmed by the recent studies of human genetic variants of MTNR1B. Remarkably, it was also suggested that genetic variations within MTNR1B disordered β-cells function directly, i.e. insulin secretion. This indicated the functional link between MT2 and T2D risk at the protein level, and it may represent the prevailing pathomechanism for how impaired melatonin signaling causes metabolic disorders and increases the T2D risk. It is speculated that melatonin and its receptors may be a new therapeutic avenue in diabetes.

  8. Adenosine A2A receptor binding profile of two antagonists, ST1535 and KW6002: consideration on the presence of atypical adenosine A2A binding sites

    Directory of Open Access Journals (Sweden)

    Teresa Riccioni

    2010-08-01

    Full Text Available Adenosine A2A receptors seem to exist in typical (more in striatum and atypical (more in hippocampus and cortex subtypes. In the present study, we investigated the affinity of two adenosine A2A receptor antagonists, ST1535 [2 butyl -9-methyl-8-(2H-1,2,3-triazol 2-yl-9H-purin-6-xylamine] and KW6002 [(E-1,3-diethyl-8-(3,4-dimethoxystyryl-7-methyl-3,7-dihydro-1H-purine-2,6,dione] to the “typical” and “atypical” A2A binding sites. Affinity was determined by radioligand competition experiments in membranes from rat striatum and hippocampus. Displacement of the adenosine analog [3H]CGS21680 [2-p-(2-carboxyethylphenethyl-amino-5’-N-ethylcarbox-amidoadenosine] was evaluated in the absence or in the presence of either CSC [8-(3-chlorostyryl-caffeine], an adenosine A2A antagonist that pharmacologically isolates atypical binding sites, or DPCPX (8-cyclopentyl-1,3-dipropylxanthine, an adenosine A1 receptor antagonist that pharmacologically isolates typical binding site. ZM241385 [84-(2-[7-amino-2-(2-furyl [1,2,4]-triazol[2,3-a][1,3,5]triazin-5-yl amino]ethyl phenol] and SCH58261 [(5-amino-7-(β-phenylethyl-2-(8-furylpyrazolo(4,3-e-1,2,4-triazolo(1,5-c pyrimidine], two other adenosine A2A receptor antagonists, which were reported to differently bind to atypical and typical A2A receptors, were used as reference compounds. ST1535, KW6002, ZM241385 and SCH58261 displaced [3H]CGS21680 with higher affinity in striatum than in hippocampus. In hippocampus, no typical adenosine A2A binding was detected, and ST1535 was the only compound that occupied atypical A2A adenosine receptors. Present data are explained in terms of heteromeric association among adenosine A2A, A2B and A1 receptors, rather than with the presence of atypical A2A receptor subtype.

  9. A strategy using NMR peptide structures of thromboxane A2 receptor as templates to construct ligand-recognition pocket of prostacyclin receptor

    Directory of Open Access Journals (Sweden)

    Ruan Ke-He

    2005-11-01

    Full Text Available Abstract Background: Prostacyclin receptor (IP and thromboxane A2 receptor (TP belong to rhodopsin-type G protein-coupling receptors and respectively bind to prostacyclin and thromboxane A2 derived from arachidonic acid. Recently, we have determined the extracellular loop (eLP structures of the human TP receptor by 2-D 1H NMR spectroscopy using constrained peptides mimicking the individual eLP segments. The studies have identified the segment along with several residues in the eLP domains important to ligand recognition, as well as proposed a ligand recognition pocket for the TP receptor. Results: The IP receptor shares a similar primary structure in the eLPs with those of the TP receptor. Forty percent residues in the second eLPs of the receptors are identical, which is the major region involved in forming the ligand recognition pocket in the TP receptor. Based on the high homology score, the eLP domains of the IP receptor were constructed by the homology modeling approach using the NMR structures of the TP eLPs as templates, and then configured to the seven transmembrane (TM domains model constructed using the crystal structure of the bovine rhodopsin as a template. A NMR structure of iloprost was docked into the modeled IP ligand recognition pocket. After dynamic studies, the segments and residues involved in the IP ligand recognition were proposed. A key residue, Arg173 involved in the ligand recognition for the IP receptor, as predicted from the modeling, was confirmed by site-directed mutagenesis. Conclusion: A 3-D model of the human IP receptor was constructed by homology modeling using the crystal structure of bovine rhodopsin TM domains and the NMR structures of the synthetic constrained peptides of the eLP domains of the TP receptor as templates. This strategy can be applied to molecular modeling and the prediction of ligand recognition pockets for other prostanoid receptors.

  10. Annexin A2 is a natural extrahepatic inhibitor of the PCSK9-induced LDL receptor degradation.

    Directory of Open Access Journals (Sweden)

    Nabil G Seidah

    Full Text Available Proprotein convertase subtilisin/kexin-9 (PCSK9 enhances the degradation of hepatic low-density lipoprotein receptor (LDLR. Deletion of PCSK9, and loss-of-function mutants in humans result in lower levels of circulating LDL-cholesterol and a strong protection against coronary heart disease. Accordingly, the quest for PCSK9 inhibitors has major clinical implications. We have previously identified annexin A2 (AnxA2 as an endogenous binding partner and functional inhibitor of PCSK9. Herein, we studied the relevance of AnxA2 in PCSK9 inhibition and lipid metabolism in vivo. Plasma analyses of AnxA2(-/- mice revealed: i a ∼1.4-fold increase in LDL-cholesterol without significant changes in VLDLs or HDLs, and ii a ∼2-fold increase in circulating PCSK9 levels. Western blotting and immunohistochemistry of AnxA2(-/- tissues revealed that the LDLR was decreased by ∼50% in extrahepatic tissues, such as adrenals and colon. We also show that AnxA2-derived synthetic peptides block the PCSK9≡LDLR interaction in vitro, and adenoviral overexpression of AnxA2 in mouse liver increases LDLR protein levels in vivo. These results suggest that AnxA2 acts as an endogenous regulator of LDLR degradation, mostly in extrahepatic tissues. Finally, we identified an AnxA2 coding polymorphism, V98L, that correlates with lower circulating levels of PCSK9 thereby extending our results on the physiological role of AnxA2 in humans.

  11. Tannic Acid Preferentially Targets Estrogen Receptor-Positive Breast Cancer

    Directory of Open Access Journals (Sweden)

    Brian W. Booth

    2013-01-01

    Full Text Available Research efforts investigating the potential of natural compounds in the fight against cancer are growing. Tannic acid (TA belongs to the class of hydrolysable tannins and is found in numerous plants and foods. TA is a potent collagen cross-linking agent; the purpose of this study was to generate TA-cross-linked beads and assess the effects on breast cancer cell growth. Collagen beads were stable at body temperature following crosslinking. Exposure to collagen beads with higher levels of TA inhibited proliferation and induced apoptosis in normal and cancer cells. TA-induced apoptosis involved activation of caspase 3/7 and caspase 9 but not caspase 8. Breast cancer cells expressing the estrogen receptor were more susceptible to the effects of TA. Taken together the results suggest that TA has the potential to become an anti-ER+ breast cancer treatment or preventative agent.

  12. Minireview: Endocannabinoids and their receptors as targets for obesity therapy.

    Science.gov (United States)

    de Kloet, Annette D; Woods, Stephen C

    2009-06-01

    As the incidence of obesity continues to increase, the development of effective therapies is a high priority. The endocannabinoid system has emerged as an important influence on the regulation of energy homeostasis. The endocannabinoids anandamide and 2-arachidonoylglycerol act on cannabinoid receptor-1 (CB1) in the brain and many peripheral tissues causing a net anabolic action. This includes increasing food intake, and causing increased lipogenesis and fat storage in adipose tissue and liver. The endocannabinoid system is hyperactive in obese humans and animals, and treating them with CB1 antagonists causes weight loss and improved lipid and glucose profiles. Although clinical trials with CB1 antagonists have yielded beneficial metabolic effects, concerns about negative affect have limited the therapeutic potential of the first class of CB1 antagonists available.

  13. Discovery of functional monoclonal antibodies targeting G-protein-coupled receptors and ion channels.

    Science.gov (United States)

    Wilkinson, Trevor C I

    2016-06-15

    The development of recombinant antibody therapeutics is a significant area of growth in the pharmaceutical industry with almost 50 approved monoclonal antibodies on the market in the US and Europe. Despite this growth, however, certain classes of important molecular targets have remained intractable to therapeutic antibodies due to complexity of the target molecules. These complex target molecules include G-protein-coupled receptors and ion channels which represent a large potential target class for therapeutic intervention with monoclonal antibodies. Although these targets have typically been addressed by small molecule approaches, the exquisite specificity of antibodies provides a significant opportunity to provide selective modulation of these target proteins. Given this opportunity, substantial effort has been applied to address the technical challenges of targeting these complex membrane proteins with monoclonal antibodies. In this review recent progress made in the strategies for discovery of functional monoclonal antibodies for these challenging membrane protein targets is addressed.

  14. Insect odorant receptors are molecular targets of the insect repellent DEET.

    Science.gov (United States)

    Ditzen, Mathias; Pellegrino, Maurizio; Vosshall, Leslie B

    2008-03-28

    DEET (N,N-diethyl-meta-toluamide) is the world's most widely used topical insect repellent, with broad effectiveness against most insects. Its mechanism of action and molecular target remain unknown. Here, we show that DEET blocks electrophysiological responses of olfactory sensory neurons to attractive odors in Anopheles gambiae and Drosophila melanogaster. DEET inhibits behavioral attraction to food odors in Drosophila, and this inhibition requires the highly conserved olfactory co-receptor OR83b. DEET inhibits odor-evoked currents mediated by the insect odorant receptor complex, comprising a ligand-binding subunit and OR83b. We conclude that DEET masks host odor by inhibiting subsets of heteromeric insect odorant receptors that require the OR83b co-receptor. The identification of candidate molecular targets for the action of DEET may aid in the design of safer and more effective insect repellents.

  15. The A2B adenosine receptor modulates pulmonary hypertension associated with interstitial lung disease.

    Science.gov (United States)

    Karmouty-Quintana, Harry; Zhong, Hongyan; Acero, Luis; Weng, Tingting; Melicoff, Ernestina; West, James D; Hemnes, Anna; Grenz, Almut; Eltzschig, Holger K; Blackwell, Timothy S; Xia, Yang; Johnston, Richard A; Zeng, Dewan; Belardinelli, Luiz; Blackburn, Michael R

    2012-06-01

    Development of pulmonary hypertension is a common and deadly complication of interstitial lung disease. Little is known regarding the cellular and molecular mechanisms that lead to pulmonary hypertension in patients with interstitial lung disease, and effective treatment options are lacking. The purpose of this study was to examine the adenosine 2B receptor (A(2B)R) as a regulator of vascular remodeling and pulmonary hypertension secondary to pulmonary fibrosis. To accomplish this, cellular and molecular changes in vascular remodeling were monitored in mice exposed to bleomycin in conjunction with genetic removal of the A(2B)R or treatment with the A(2B)R antagonist GS-6201. Results demonstrated that GS-6201 treatment or genetic removal of the A(2B)R attenuated vascular remodeling and hypertension in our model. Furthermore, direct A(2B)R activation on vascular cells promoted interleukin-6 and endothelin-1 release. These studies identify a novel mechanism of disease progression to pulmonary hypertension and support the development of A(2B)R antagonists for the treatment of pulmonary hypertension secondary to interstitial lung disease.

  16. G-protein-coupled receptors for free fatty acids: nutritional and therapeutic targets

    OpenAIRE

    Milligan, Graeme; Ulven, Trond; Murdoch, Hannah; Hudson, Brian D.

    2014-01-01

    It is becoming evident that nutrients and metabolic intermediates derived from such nutrients regulate cellular function by activating a number of cell-surface G-protein coupled receptors (GPCRs). Until now, members of the GPCR family have largely been considered as the molecular targets that communicate cellular signals initiated by hormones and neurotransmitters. Recently, based on tissue expression patterns of these receptors and the concept that they may elicit the production of a range o...

  17. Cannabinoid Receptor 2 Signaling in Neurodegenerative Disorders: From Pathogenesis to a Promising Therapeutic Target

    Science.gov (United States)

    Cassano, Tommaso; Calcagnini, Silvio; Pace, Lorenzo; De Marco, Federico; Romano, Adele; Gaetani, Silvana

    2017-01-01

    As a consequence of an increasingly aging population, the number of people affected by neurodegenerative disorders, such as Alzheimer's disease, Parkinson's disease and Huntington's disease, is rapidly increasing. Although the etiology of these diseases has not been completely defined, common molecular mechanisms including neuroinflammation, excitotoxicity and mitochondrial dysfunction have been confirmed and can be targeted therapeutically. Moreover, recent studies have shown that endogenous cannabinoid signaling plays a number of modulatory roles throughout the central nervous system (CNS), including the neuroinflammation and neurogenesis. In particular, the up-regulation of type-2 cannabinoid (CB2) receptors has been found in a number of neurodegenerative disorders. Thus, the modulation of CB2 receptor signaling may represent a promising therapeutic target with minimal psychotropic effects that can be used to modulate endocannabinoid-based therapeutic approaches and to reduce neuronal degeneration. For these reasons this review will focus on the CB2 receptor as a promising pharmacological target in a number of neurodegenerative diseases. PMID:28210207

  18. Conjugation with receptor-targeted histidine-rich peptides enhances the pharmacological effectiveness of antisense oligonucleotides.

    Science.gov (United States)

    Nakagawa, Osamu; Ming, Xin; Carver, Kyle; Juliano, Rudy

    2014-01-15

    Ineffective delivery to intracellular sites of action is one of the key limitations to the use of antisense and siRNA oligonucleotides as therapeutic agents. Here, we describe molecular scale antisense oligonucleotide conjugates that bind selectively to a cell surface receptor, are internalized, and then partially escape from nonproductive endosomal locations to reach their sites of action in the nucleus. Peptides that include bombesin sequences for receptor targeting and a run of histidine residues for endosomal disruption were covalently linked to a splice switching antisense oligonucleotide. The conjugates were tested for their ability to correct splicing and up-regulate expression of a luciferase reporter in prostate cancer cells that express the bombesin receptor. We found that trivalent conjugates that included both the targeting sequence and several histidine residues were substantially more effective than conjugates containing only the bombesin or histidine moieties. This demonstrates the potential of creating molecular scale oligonucleotide conjugates with both targeting and endosome escape capabilities.

  19. Targeting of peptide conjugated magnetic nanoparticles to urokinase plasminogen activator receptor (uPAR) expressing cells

    DEFF Research Database (Denmark)

    Hansen, Line; Unmack Larsen, Esben Kjær; Nielsen, Erik Holm

    2013-01-01

    Ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles are currently being used as a magnetic resonance imaging (MRI) contrast agent in vivo, mainly by their passive accumulation in tissues of interest. However, a higher specificity can ideally be achieved when the nanoparticles are targeted...... towards cell specific receptors and this may also facilitate specific drug delivery by an enhanced target-mediated endocytosis. We report efficient peptide-mediated targeting of magnetic nanoparticles to cells expressing the urokinase plasminogen activator receptor (uPAR), a surface biomarker for poor...... to nanoparticles carrying a non-binding control peptide. In accordance with specific receptor-mediated recognition, a low uptake was observed in the presence of an excess of ATF, a natural ligand for uPAR. The uPAR specific magnetic nanoparticles can potentially provide a useful supplement for tumor patient...

  20. Recognition and sensing of low-epitope targets via ternary complexes with oligonucleotides and synthetic receptors

    Science.gov (United States)

    Yang, Kyung-Ae; Barbu, Mihaela; Halim, Marlin; Pallavi, Payal; Kim, Benjamin; Kolpashchikov, Dmitry M.; Pecic, Stevan; Taylor, Steven; Worgall, Tilla S.; Stojanovic, Milan N.

    2014-11-01

    Oligonucleotide-based receptors or aptamers can interact with small molecules, but the ability to achieve high-affinity and specificity of these interactions depends strongly on functional groups or epitopes displayed by the binding targets. Some classes of targets are particularly challenging: for example, monosaccharides have scarce functionalities and no aptamers have been reported to recognize, let alone distinguish from each other, glucose and other hexoses. Here we report aptamers that differentiate low-epitope targets such as glucose, fructose or galactose by forming ternary complexes with high-epitope organic receptors for monosaccharides. In a follow-up example, we expand this method to isolate high-affinity oligonucleotides against aromatic amino acids complexed in situ with a nonspecific organometallic receptor. The method is general and enables broad clinical use of aptamers for the detection of small molecules in mix-and-measure assays, as demonstrated by monitoring postprandial waves of phenylalanine in human subjects.

  1. Structural and energetic effects of A2A adenosine receptor mutations on agonist and antagonist binding.

    Directory of Open Access Journals (Sweden)

    Henrik Keränen

    Full Text Available To predict structural and energetic effects of point mutations on ligand binding is of considerable interest in biochemistry and pharmacology. This is not only useful in connection with site-directed mutagenesis experiments, but could also allow interpretation and prediction of individual responses to drug treatment. For G-protein coupled receptors systematic mutagenesis has provided the major part of functional data as structural information until recently has been very limited. For the pharmacologically important A(2A adenosine receptor, extensive site-directed mutagenesis data on agonist and antagonist binding is available and crystal structures of both types of complexes have been determined. Here, we employ a computational strategy, based on molecular dynamics free energy simulations, to rationalize and interpret available alanine-scanning experiments for both agonist and antagonist binding to this receptor. These computer simulations show excellent agreement with the experimental data and, most importantly, reveal the molecular details behind the observed effects which are often not immediately evident from the crystal structures. The work further provides a distinct validation of the computational strategy used to assess effects of point-mutations on ligand binding. It also highlights the importance of considering not only protein-ligand interactions but also those mediated by solvent water molecules, in ligand design projects.

  2. Progress on the M-type phospholipase A2 receptor in idiopathic membranous nephropathy

    Institute of Scientific and Technical Information of China (English)

    Wang Chao; Lu Huan; Yang Cui; Luo Yuezhong

    2014-01-01

    Objective To highlight current knowledge about M-type phospholipase A2 receptor (PLA2R) which is the first human autoantigen discovered in adult idiopathic membranous nephropathy.Data sources Relevant articles published in English from 2000 to present were selected from PubMed.Searches were made using the terms "idiopathic membranous nephropathy,M-type PLA2R and podocyte." Study selection Articles studying the role of M-type PLA2R in idiopathic membranous nephropathy were reviewed.Articles focusing on the discovery,detection and clinical observation of anti-PLA2R antibodies were selected.Results M-type PLA2R is a member of the mannose receptor family of proteins,locating on normal human glomeruli as a transmembrane receptor.The anti-PLA2R in serum samples from MN were primarily IgG4 subclass.Technologies applied to detect anti-PLA2R autoantibody are mainly WB,lIFT,ELISA and so on.Studies from domestic and overseas have identified a strongly relationship between circulating anti-PLA2R levels and disease activity.Conclusion Recent discoveries corresponding to PLA2R facilitate a better understanding on IMN pathogenesis and may provide a new tool to its diagnosis,differential diagnosis,risk evaluation,response monitoring and patient-specific treatment.

  3. The sigma-2 receptor as a therapeutic target for drug delivery in triple negative breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Makvandi, Mehran; Tilahun, Estifanos D.; Lieberman, Brian P.; Anderson, Redmond-Craig; Zeng, Chenbo; Xu, Kuiying; Hou, Catherine; McDonald, Elizabeth S.; Pryma, Daniel A.; Mach, Robert H., E-mail: rmach@mail.med.upenn.edu

    2015-11-27

    Background: Triple-negative breast cancer (TNBC) is associated with high relapse rates and increased mortality when compared with other breast cancer subtypes. In contrast to receptor positive breast cancers, there are no approved targeted therapies for TNBC. Identifying biomarkers for TNBC is of high importance for the advancement of patient care. The sigma-2 receptor has been shown to be overexpressed in triple negative breast cancer in vivo and has been characterized as a marker of proliferation. The aim of the present study was to define the sigma-2 receptor as a target for therapeutic drug delivery and biomarker in TNBC. Methods: Three TNBC cell lines were evaluated: MDA-MB-231, HCC1937 and HCC1806. Sigma-2 compounds were tested for pharmacological properties specific to the sigma-2 receptor through competitive inhibition assays. Sigma-2 receptor expression was measured through radioligand receptor saturation studies. Drug sensitivity for taxol was compared to a sigma-2 targeting compound conjugated to a cytotoxic payload, SW IV-134. Cell viability was assessed after treatments for 2 or 48 h. Sigma-2 blockade was assessed to define sigma-2 mediated cytotoxicity of SW IV-134. Caspase 3/7 activation induced by SW IV-134 was measured at corresponding treatment time points. Results: SW IV-134 was the most potent compound tested in two of the three cell lines and was similarly effective in all three. MDA-MB-231 displayed a statistically significant higher sigma-2 receptor expression and also was the most sensitive cell line evaluated to SW IV-134. Conclusion: Targeting the sigma-2 receptor with a cytotoxic payload was effective in all the three cell lines evaluated and provides the proof of concept for future development of a therapeutic platform for the treatment of TNBC. - Highlights: • TNBC cells are sensitive to sigma-2 receptor targeted drug conjugate SW IV-134. • MDA-MB-231 displayed the highest amount of sigma-2 receptors and corresponded well with

  4. Expression of folate receptors in nasopharyngeal and laryngeal carcinoma and folate receptor-mediated endocytosis by molecular targeted nanomedicine

    Directory of Open Access Journals (Sweden)

    Xie M

    2013-07-01

    Full Text Available M Xie, H Zhang, Y Xu, T Liu, S Chen, J Wang, T ZhangDepartment of Otorhinolaryngology Head and Neck Surgery, Zhujiang Hospital, Southern Medical University, Guangzhou, People's Republic of ChinaAbstract: Immunohistochemistry and an immunofluorescence technique was used to detect folate receptor expression in tissue samples and cell lines of head and neck squamous carcinoma, including 20 tissue samples of nasopharyngeal carcinoma, 16 tissue samples of laryngeal carcinoma, and HNE-1, HNE-2, CNE-1, CNE-2, SUNE-1, 5-8F, and Hep-2 cell lines. Iron staining, electron microscopy, and magnetic resonance imaging were used to observe endocytosis of folate-conjugated cisplatin-loaded magnetic nanoparticles (CDDP-FA-ASA-MNP in cultured cells and transplanted tumors. As shown by immunohistochemistry, 83.3% (30/36 of the head and neck squamous carcinomas expressed the folate receptor versus none in the control group (0/24. Only the HNE-1 and Hep-2 cell lines expressed the folate receptor, and the other five cell lines did not. Endocytosis of CDDP-FA-ASA-MNP was seen in HNE-1 and Hep-2 cells by iron staining and electron microscopy. A similar result was seen in transplanted tumors in nude mice. Magnetic resonance imaging showed low signal intensity of HNE-1 cells and HNE-1 transplanted tumors on T2-weighted images after uptake of CDDP-FA-ASA-MNP, and this was not seen in CNE-2 transplanted tumors. In conclusion, head and neck squamous carcinoma cell strongly expressed the folate receptor, while normal tissue did not. The folate receptor can mediate endocytosis of folate-conjugated anticancer nanomedicines, and lays the foundation for molecular targeted treatment of cancer.Keywords: nasopharyngeal carcinoma, laryngeal carcinoma, folate receptor, molecular targeting, cisplatin, nanomedicine

  5. Construction and application of elastin like polypeptide containing IL-4 receptor targeting peptide.

    Directory of Open Access Journals (Sweden)

    Vijaya Sarangthem

    Full Text Available Various human solid tumors highly express IL-4 receptors which amplify the expression of some of anti-apoptotic proteins, preventing drug-induced cancer cell death. Thus, IL-4 receptor targeted drug delivery can possibly increase the therapeutic efficacy in cancer treatment. Macromolecular carriers with multivalent targeting moieties offered great advantages in cancer therapy as they not only increase the plasma half-life of the drug but also allow delivery of therapeutic drugs to the cancer cells with higher specificity, minimizing the deleterious effects of the drug on normal cells. In this study we designed a library of elastin like polypeptide (ELP polymers containing tumor targeting AP1 peptide using recursive directional ligation method. AP1 was previously discovered as an atherosclerotic plaque and breast tumor tissue homing peptide using phage display screening method, and it can selectively bind to the interleukin 4 receptor (IL-4R. The fluorescently labeled [AP1-V12]6, an ELP polymer containing six AP1 enhanced tumor-specific targeting ability and uptake efficiency in H226 and MDA-MB-231 cancer cell lines in vitro. Surface plasmon resonance analysis showed that multivalent presentation of the targeting ligand in the ELP polymer increased the binding affinity towards IL-4 receptor compared to free peptide. The binding of [AP1-V12]6 to cancer cells was remarkably reduced when IL-4 receptors were blocked by antibody against IL-4 receptor further confirmed its binding. Importantly, the Cy5.5-labeled [AP1-V12]6 demonstrated excellent homing and longer retention in tumor tissues in MDA-MB-231 xenograft mouse model. Immunohistological studies of tumor tissues further validated the targeting efficiency of [AP1-V12]6 to tumor tissue. These results indicate that designed [AP1-V12]6 can serve as a novel carrier for selective delivery of therapeutic drugs to tumors.

  6. The Vasopressin Type-2 Receptor and Prostaglandin Receptors EP2 and EP4 can Increase Aquaporin-2 Plasma Membrane Targeting Through a cAMP Independent Pathway

    DEFF Research Database (Denmark)

    Olesen, Emma Tina Bisgaard; Moeller, Hanne Bjerregaard; Assentoft, Mette

    2016-01-01

    Apical membrane targeting of the collecting duct water channel aquaporin-2 (AQP2) is essential for body water balance. As this event is regulated by Gs coupled 7-transmembrane receptors such as the vasopressin type 2 receptor (V2R) and the prostanoid receptors EP2 and EP4, it is believed to be cA...

  7. Atomic force microscopy probing of receptor-nanoparticle interactions for riboflavin receptor targeted gold-dendrimer nanocomposites.

    Science.gov (United States)

    Witte, Amanda B; Leistra, Abigail N; Wong, Pamela T; Bharathi, Sophia; Refior, Kevin; Smith, Phillip; Kaso, Ola; Sinniah, Kumar; Choi, Seok Ki

    2014-03-20

    Riboflavin receptors are overexpressed in malignant cells from certain human breast and prostate cancers, and they constitute a group of potential surface markers important for cancer targeted delivery of therapeutic agents and imaging molecules. Here we report on the fabrication and atomic force microscopy (AFM) characterization of a core-shell nanocomposite consisting of a gold nanoparticle (AuNP) coated with riboflavin receptor-targeting poly(amido amine) dendrimer. We designed this nanocomposite for potential applications such as a cancer targeted imaging material based on its surface plasmon resonance properties conferred by AuNP. We employed AFM as a technique for probing the binding interaction between the nanocomposite and riboflavin binding protein (RfBP) in solution. AFM enabled precise measurement of the AuNP height distribution before (13.5 nm) and after chemisorption of riboflavin-conjugated dendrimer (AuNP-dendrimer; 20.5 nm). Binding of RfBP to the AuNP-dendrimer caused a height increase to 26.7 nm, which decreased to 22.8 nm when coincubated with riboflavin as a competitive ligand, supporting interaction of AuNP-dendrimer and its target protein. In summary, physical determination of size distribution by AFM imaging can serve as a quantitative approach to monitor and characterize the nanoscale interaction between a dendrimer-covered AuNP and target protein molecules in vitro.

  8. GHB receptor targets in the CNS: focus on high-affinity binding sites.

    Science.gov (United States)

    Bay, Tina; Eghorn, Laura F; Klein, Anders B; Wellendorph, Petrine

    2014-01-15

    γ-Hydroxybutyric acid (GHB) is an endogenous compound in the mammalian brain with both low- and high-affinity receptor targets. GHB is used clinically in the treatment of symptoms of narcolepsy and alcoholism, but also illicitly abused as the recreational drug Fantasy. Major pharmacological effects of exogenous GHB are mediated by GABA subtype B (GABAB) receptors that bind GHB with low affinity. The existence of GHB high-affinity binding sites has been known for more than three decades, but the uncovering of their molecular identity has only recently begun. This has been prompted by the generation of molecular tools to selectively study high-affinity sites. These include both genetically modified GABAB knock-out mice and engineered selective GHB ligands. Recently, certain GABA subtype A (GABAA) receptor subtypes emerged as high-affinity GHB binding sites and potential physiological mediators of GHB effects. In this research update, a description of the various reported receptors for GHB is provided, including GABAB receptors, certain GABAA receptor subtypes and other reported GHB receptors. The main focus will thus be on the high-affinity binding targets for GHB and their potential functional roles in the mammalian brain.

  9. Role of antibodies in developing drugs that target G-protein-coupled receptor dimers.

    Science.gov (United States)

    Hipser, Chris; Bushlin, Ittai; Gupta, Achla; Gomes, Ivone; Devi, Lakshmi A

    2010-01-01

    G-protein-coupled receptors are important molecular targets in drug discovery. These receptors play a pivotal role in physiological signaling pathways and are targeted by nearly 50% of currently available drugs. Mounting evidence suggests that G-protein-coupled receptors form dimers, and various studies have shown that dimerization is necessary for receptor maturation, signaling, and trafficking. However, the physiological implications of dimerization in vivo have not been well explored because detection of GPCR dimers in endogenous systems has been a challenging task. One exciting new approach to this challenge is the generation of antibodies against specific G-protein-coupled receptor dimers. Such antibodies could be used as tools for characterization of heteromer-specific function; as reagents for their purification, tissue localization, and regulation in vivo; and as probes for mapping their functional domains. In addition, such antibodies could serve as alternative ligands for G-protein-coupled receptor heteromers. Thus, heteromer-specific antibodies represent novel tools for the exploration and manipulation of G-protein-coupled receptor-dimer pharmacology.

  10. G protein coupled receptors of the renin-angiotensin system: new targets against breast cancer?

    Directory of Open Access Journals (Sweden)

    Clara eNAHMIAS

    2015-02-01

    Full Text Available G-protein coupled receptors (GPCRs constitute the largest family of membrane receptors, with high potential for drug discovery. These receptors can be activated by a panel of different ligands including ions, hormones, small molecules and vasoactive peptides. Among those, angiotensins (angiotensin II and angiotensin 1-7 are the major biologically active products of the classical and alternative Renin-Angiotensin System (RAS. These peptides bind and activate three different subtypes of GPCRs, namely AT1, AT2 and Mas receptors, to regulate cardiovascular functions. Over the past decade, the contribution of several RAS components in tumorigenesis has emerged as a novel important concept, Angiotensin II being considered as harmful and Angiotensin 1-7 as protective against cancer. Development of selective ligands targeting each RAS receptor may provide novel and efficient targeted therapeutic strategies against cancer. In this review, we focus on breast cancer to summarize current knowledge on angiotensin receptors (AT1, AT2, and Mas, and discuss the potential use of angiotensin receptor agonists and antagonists in clinics.

  11. Folate Receptor Targeted Alpha-Therapy Using Terbium-149

    CERN Document Server

    Müller, Cristina; Haller, Stephanie; Dorrer, Holger; Köster, Ulli; Johnston, Karl; Zhernosekov, Konstantin; Türler, Andreas; Schibli, Roger

    2014-01-01

    Terbium-149 is among the most interesting therapeutic nuclides for medical applications. It decays by emission of short-range α-particles (Eα = 3.967 MeV) with a half-life of 4.12 h. The goal of this study was to investigate the anticancer efficacy of a 149Tb-labeled DOTA-folate conjugate (cm09) using folate receptor (FR)-positive cancer cells in vitro and in tumor-bearing mice. 149Tb was produced at the ISOLDE facility at CERN. Radiolabeling of cm09 with purified 149Tb resulted in a specific activity of ~1.2 MBq/nmol. In vitro assays performed with 149Tb-cm09 revealed a reduced KB cell viability in a FR-specific and activity concentration-dependent manner. Tumor-bearing mice were injected with saline only (group A) or with 149Tb-cm09 (group B: 2.2 MBq; group C: 3.0 MBq). A significant tumor growth delay was found in treated animals resulting in an increased average survival time of mice which received 149Tb-cm09 (B: 30.5 d; C: 43 d) compared to untreated controls (A: 21 d). Analysis of blood parameters rev...

  12. Expression of androgen receptor target genes in skeletal muscle.

    Science.gov (United States)

    Rana, Kesha; Lee, Nicole K L; Zajac, Jeffrey D; MacLean, Helen E

    2014-01-01

    We aimed to determine the mechanisms of the anabolic actions of androgens in skeletal muscle by investigating potential androgen receptor (AR)-regulated genes in in vitro and in vivo models. The expression of the myogenic regulatory factor myogenin was significantly decreased in skeletal muscle from testosterone-treated orchidectomized male mice compared to control orchidectomized males, and was increased in muscle from male AR knockout mice that lacked DNA binding activity (AR(ΔZF2)) versus wildtype mice, demonstrating that myogenin is repressed by the androgen/AR pathway. The ubiquitin ligase Fbxo32 was repressed by 12 h dihydrotestosterone treatment in human skeletal muscle cell myoblasts, and c-Myc expression was decreased in testosterone-treated orchidectomized male muscle compared to control orchidectomized male muscle, and increased in AR(∆ZF2) muscle. The expression of a group of genes that regulate the transition from myoblast proliferation to differentiation, Tceal7 , p57(Kip2), Igf2 and calcineurin Aa, was increased in AR(∆ZF2) muscle, and the expression of all but p57(Kip2) was also decreased in testosterone-treated orchidectomized male muscle compared to control orchidectomized male muscle. We conclude that in males, androgens act via the AR in part to promote peak muscle mass by maintaining myoblasts in the proliferative state and delaying the transition to differentiation during muscle growth and development, and by suppressing ubiquitin ligase-mediated atrophy pathways to preserve muscle mass in adult muscle.

  13. Expression of androgen receptor target genes in skeletal muscle

    Institute of Scientific and Technical Information of China (English)

    Kesha Rana; Nicole KL Lee; Jeffrey D Zajac; Helen E MacLean

    2014-01-01

    We aimed to determine the mechanisms of the anabolic actions of androgens in skeletal muscle by investigating potential androgen receptor(AR)‑regulated genes ininvitroandinvivomodels. The expression of the myogenic regulatory factormyogenin was signiifcantly decreased in skeletal muscle from testosterone‑treated orchidectomized male mice compared to control orchidectomized males, and was increased in muscle from male AR knockout mice that lacked DNA binding activity(ARΔZF2) versus wildtype mice, demonstrating thatmyogenin is repressed by the androgen/AR pathway. The ubiquitin ligaseFbxo32 was repressed by 12h dihydrotestosterone treatment in human skeletal muscle cell myoblasts, andc‑Myc expression was decreased in testosterone‑treated orchidectomized male muscle compared to control orchidectomized male muscle, and increased in AR∆ZF2 muscle. The expression of a group of genes that regulate the transition from myoblast proliferation to differentiation, Tceal7, p57Kip2, Igf2 andcalcineurin Aa, was increased in AR∆ZF2 muscle, and the expression of all butp57Kip2was also decreased in testosterone‑treated orchidectomized male muscle compared to control orchidectomized male muscle. We conclude that in males, androgens act via the AR in part to promote peak muscle mass by maintaining myoblasts in the proliferative state and delaying the transition to differentiation during muscle growth and development, and by suppressing ubiquitin ligase‑mediated atrophy pathways to preserve muscle mass in adult muscle.

  14. Folate Receptor Targeted Alpha-Therapy Using Terbium-149

    Directory of Open Access Journals (Sweden)

    Cristina Müller

    2014-03-01

    Full Text Available Terbium-149 is among the most interesting therapeutic nuclides for medical applications. It decays by emission of short-range α-particles (Eα = 3.967 MeV with a half-life of 4.12 h. The goal of this study was to investigate the anticancer efficacy of a 149Tb-labeled DOTA-folate conjugate (cm09 using folate receptor (FR-positive cancer cells in vitro and in tumor-bearing mice. 149Tb was produced at the ISOLDE facility at CERN. Radiolabeling of cm09 with purified 149Tb resulted in a specific activity of ~1.2 MBq/nmol. In vitro assays performed with 149Tb-cm09 revealed a reduced KB cell viability in a FR-specific and activity concentration-dependent manner. Tumor-bearing mice were injected with saline only (group A or with 149Tb-cm09 (group B: 2.2 MBq; group C: 3.0 MBq. A significant tumor growth delay was found in treated animals resulting in an increased average survival time of mice which received 149Tb-cm09 (B: 30.5 d; C: 43 d compared to untreated controls (A: 21 d. Analysis of blood parameters revealed no signs of acute toxicity to the kidneys or liver in treated mice over the time of investigation. These results demonstrated the potential of folate-based α-radionuclide therapy in tumor-bearing mice.

  15. Expression of androgen receptor target genes in skeletal muscle

    Directory of Open Access Journals (Sweden)

    Kesha Rana

    2014-10-01

    Full Text Available We aimed to determine the mechanisms of the anabolic actions of androgens in skeletal muscle by investigating potential androgen receptor (AR-regulated genes in in vitro and in vivo models. The expression of the myogenic regulatory factor myogenin was significantly decreased in skeletal muscle from testosterone-treated orchidectomized male mice compared to control orchidectomized males, and was increased in muscle from male AR knockout mice that lacked DNA binding activity (ARΔZF2 versus wildtype mice, demonstrating that myogenin is repressed by the androgen/AR pathway. The ubiquitin ligase Fbxo32 was repressed by 12 h dihydrotestosterone treatment in human skeletal muscle cell myoblasts, and c-Myc expression was decreased in testosterone-treated orchidectomized male muscle compared to control orchidectomized male muscle, and increased in AR∆ZF2 muscle. The expression of a group of genes that regulate the transition from myoblast proliferation to differentiation, Tceal7 , p57 Kip2, Igf2 and calcineurin Aa, was increased in AR∆ZF2 muscle, and the expression of all but p57 Kip2 was also decreased in testosterone-treated orchidectomized male muscle compared to control orchidectomized male muscle. We conclude that in males, androgens act via the AR in part to promote peak muscle mass by maintaining myoblasts in the proliferative state and delaying the transition to differentiation during muscle growth and development, and by suppressing ubiquitin ligase-mediated atrophy pathways to preserve muscle mass in adult muscle.

  16. Autoantibodies targeting glomerular annexin A2 identify patients with proliferative lupus nephritis

    Science.gov (United States)

    Caster, Dawn J.; Korte, Erik A.; Merchant, Michael L.; Klein, Jon B.; Wilkey, Daniel W.; Rovin, Brad H.; Birmingham, Dan J.; Harley, John B.; Cobb, Beth L.; Namjou, Bahram; McLeish, Kenneth R.; Powell, David W.

    2015-01-01

    PURPOSE Patients with systemic lupus erythematosus (SLE) frequently develop lupus nephritis (LN), a complication frequently leading to end stage kidney disease. Immune complex deposition in the glomerulus is central to the development of LN. Using a targeted proteomic approach, we tested the hypothesis that autoantibodies targeting glomerular antigens contribute to the development of LN. EXPERIMENTAL DESIGN Human podocyte and glomerular proteins were separated by SDS-PAGE and immunoblotted with sera from SLE patients with and without LN. The regions of those gels corresponding to reactive bands observed with sera from LN patients were analyzed using LC-MS/MS. RESULTS LN reactive bands were seen at approximately 50 kDa in podocyte extracts and between 36-50 kDa in glomerular extracts. Those bands were analyzed by LC-MS/MS and 102 overlapping proteins were identified. Bioinformatic analysis determined that 36 of those proteins were membrane associated, including a protein previously suggested to contribute to glomerulonephritis and LN, annexin A2. By ELISA, patients with proliferative LN demonstrated significantly increased antibodies against annexin A2. CONCLUSION AND CLINICAL RELEVANCE Proteomic approaches identified multiple candidate antigens for autoantibodies in patients with LN. Serum antibodies against annexin A2 were significantly elevated in subjects with proliferative LN, validating those antibodies as potential biomarkers. PMID:25824007

  17. Altered activity profile of a tertiary silanol analog of multi-targeting nuclear receptor modulator T0901317.

    Science.gov (United States)

    Toyama, Hirozumi; Sato, Shoko; Shirakawa, Hitoshi; Komai, Michio; Hashimoto, Yuichi; Fujii, Shinya

    2016-04-01

    We report the design, synthesis, and physicochemical/biological evaluation of novel silanol derivative 6 (sila-T) as a silanol analog of multi-target nuclear receptor modulator T0901317 (5). Compound 6 showed intermediate hydrophobicity between the corresponding alcohol 13 and perfluoroalcohol 5. While 5 exhibited potent activities toward liver X receptor α and β, farnesoid X receptor, pregnane X receptor (PXR) and retinoic acid receptor-related orphan receptor (ROR)γ, silanol 6 exhibited activity only toward PXR and RORs. Incorporation of silanol instead of perfluoroalcohol is a promising option for developing novel target-selective, biologically active compounds.

  18. Characterization of the A2B adenosine receptor from mouse, rabbit, and dog.

    Science.gov (United States)

    Auchampach, John A; Kreckler, Laura M; Wan, Tina C; Maas, Jason E; van der Hoeven, Dharini; Gizewski, Elizabeth; Narayanan, Jayashree; Maas, Garren E

    2009-04-01

    We have cloned and pharmacologically characterized the A(2B) adenosine receptor (AR) from the dog, rabbit, and mouse. The full coding regions of the dog and mouse A(2B)AR were obtained by reverse transcriptase-polymerase chain reaction, and the rabbit A(2B)AR cDNA was obtained by screening a rabbit brain cDNA library. It is noteworthy that an additional clone was isolated by library screening that was identical in sequence to the full-length rabbit A(2B)AR, with the exception of a 27-base pair deletion in the region encoding amino acids 103 to 111 (A(2B)AR(103-111)). This 9 amino acid deletion is located in the second intracellular loop at the only known splice junction of the A(2B)AR and seems to result from the use of an additional 5' donor site found in the rabbit and dog but not in the human, rat, or mouse sequences. [(3)H]3-Isobutyl-8-pyrrolidinoxanthine and 8-[4-[((4-cyano-[2,6-(3)H]-phenyl)carbamoylmethyl)oxy]phenyl]-1,3-di(n-propyl)xanthine ([(3)H]MRS 1754) bound with high affinity to membranes prepared from human embryonic kidney (HEK) 293 cells expressing mouse, rabbit, and dog A(2B)ARs. Competition binding studies performed with a panel of agonist (adenosine and 2-amino-3,5-dicyano-4-phenylpyridine analogs) and antagonist ligands identified similar potency orders for the A(2B)AR orthologs, although most xanthine antagonists displayed lower binding affinity for the dog A(2B)AR compared with A(2B)ARs from rabbit and mouse. No specific binding could be detected with membranes prepared from HEK 293 cells expressing the rabbit A(2B)AR(103-111) variant. Furthermore, the variant failed to stimulate adenylyl cyclase or calcium mobilization. We conclude that significant differences in antagonist pharmacology of the A(2B)AR exist between species and that some species express nonfunctional variants of the A(2B)AR due to "leaky" splicing.

  19. Evidence for an A2/Ra adenosine receptor in the guinea-pig trachea

    Science.gov (United States)

    Brown, C.M.; Collis, M.G.

    1982-01-01

    1 An attempt was made to determine whether the extracellular adenosine receptor that mediates relaxation in the guinea-pig trachea is of the A1/Ri or A2/Ra subtype. 2 Dose-response curves to adenosine and a number of 5′- and N6-substituted analogues were constructed for the isolated guinea-pig trachea, contracted with carbachol. 3 The 5′-substituted analogues of adenosine were the most potent compounds tested, the order of potency being 5′-N-cyclopropylcarboxamide adenosine (NCPCA) > 5′-N-ethylcarboxamide adenosine (NECA) > 2-chloroadenosine > L-N6-phenylisopropyladenosine (L-PIA) > adenosine > D-N6-phenylisopropyladenosine (D-PIA). 4 The difference in potency between the stereoisomers D- and L-PIA on the isolated trachea was at the most five fold. 5 Responses to low doses of adenosine and its analogues were attenuated after treatment with either theophylline or 8-phenyltheophylline. The responses to 2-chloroadenosine were affected to a lesser extent than were those to the other purines. 6 Adenosine transport inhibitors, dipyridamole and dilazep, potentiated responses to adenosine, did not affect those to NCPCA, NECA, L-PIA and D-PIA but significantly reduced the responses to high doses of 2-chloroadenosine. 7 Relaxations evoked by 9-β-D-xylofuranosyladenosine which can activate intracellular but not extracellular adenosine receptors, were attenuated by dipyridamole but unaffected by 8-phenyltheophylline. 8 The results support the existence of an extracellular A2/Ra subtype of adenosine receptor and an intracellular purine-sensitive site, both of which mediate relaxation. PMID:6286021

  20. Elevated Adenosine Induces Placental DNA Hypomethylation Independent of A2B Receptor Signaling in Preeclampsia.

    Science.gov (United States)

    Huang, Aji; Wu, Hongyu; Iriyama, Takayuki; Zhang, Yujin; Sun, Kaiqi; Song, Anren; Liu, Hong; Peng, Zhangzhe; Tang, Lili; Lee, Minjung; Huang, Yun; Ni, Xin; Kellems, Rodney E; Xia, Yang

    2017-07-01

    Preeclampsia is a prevalent pregnancy hypertensive disease with both maternal and fetal morbidity and mortality. Emerging evidence indicates that global placental DNA hypomethylation is observed in patients with preeclampsia and is linked to altered gene expression and disease development. However, the molecular basis underlying placental epigenetic changes in preeclampsia remains unclear. Using 2 independent experimental models of preeclampsia, adenosine deaminase-deficient mice and a pathogenic autoantibody-induced mouse model of preeclampsia, we demonstrate that elevated placental adenosine not only induces hallmark features of preeclampsia but also causes placental DNA hypomethylation. The use of genetic approaches to express an adenosine deaminase minigene specifically in placentas, or adenosine deaminase enzyme replacement therapy, restored placental adenosine to normal levels, attenuated preeclampsia features, and abolished placental DNA hypomethylation in adenosine deaminase-deficient mice. Genetic deletion of CD73 (an ectonucleotidase that converts AMP to adenosine) prevented the elevation of placental adenosine in the autoantibody-induced preeclampsia mouse model and ameliorated preeclampsia features and placental DNA hypomethylation. Immunohistochemical studies revealed that elevated placental adenosine-mediated DNA hypomethylation predominantly occurs in spongiotrophoblasts and labyrinthine trophoblasts and that this effect is independent of A2B adenosine receptor activation in both preeclampsia models. Extending our mouse findings to humans, we used cultured human trophoblasts to demonstrate that adenosine functions intracellularly and induces DNA hypomethylation without A2B adenosine receptor activation. Altogether, both mouse and human studies reveal novel mechanisms underlying placental DNA hypomethylation and potential therapeutic approaches for preeclampsia. © 2017 American Heart Association, Inc.

  1. Hepatitis B virus receptors and molecular drug targets.

    Science.gov (United States)

    Verrier, Eloi R; Colpitts, Che C; Sureau, Camille; Baumert, Thomas F

    2016-07-01

    Chronic hepatitis B virus (HBV) infection is a leading cause of liver disease worldwide. Virus-induced diseases include cirrhosis, liver failure and hepatocellular carcinoma. Current therapeutic strategies may at best control infection without reaching cure. Complementary antiviral strategies aimed at viral cure are therefore urgently needed. HBV entry is the first step of the infection cycle, which leads to the formation of cccDNA and the establishment of chronic infection. Viral entry may thus represent an attractive target for antiviral therapy. This review summarizes the molecular virology and cell biology of HBV entry, including the discovery and development of new HBV entry inhibitors, and discusses their potential in future treatment of HBV infection.

  2. Library screening and receptor-directed targeting of gammaretroviral vectors.

    Science.gov (United States)

    Mazari, Peter M; Roth, Monica J

    2013-01-01

    Gene- and cell-based therapies hold great potential for the advancement of the personalized medicine movement. Gene therapy vectors have made dramatic leaps forward since their inception. Retroviral-based vectors were the first to gain clinical attention and still offer the best hope for the long-term correction of many disorders. The fear of nonspecific transduction makes targeting a necessary feature for most clinical applications. However, this remains a difficult feature to optimize, with specificity often coming at the expense of efficiency. The aim of this article is to discuss the various methods employed to retarget retroviral entry. Our focus will lie on the modification of gammaretroviral envelope proteins with an in-depth discussion of the creation and screening of envelope libraries.

  3. GDNF control of the glutamatergic cortico-striatal pathway requires tonic activation of adenosine A2A Receptors

    Science.gov (United States)

    Gomes, Catarina A.R.V.; Simões, Patrícia F.; Canas, Paula M.; Quiroz, César; Sebastião, Ana M.; Ferré, Sergi; Cunha, Rodrigo A.; Ribeiro, Joaquim A.

    2009-01-01

    Glial cell line-derived neurotrophic factor (GDNF) affords neuroprotection in Parkinson’s disease in accordance with its ability to bolster nigrostriatal innervation. We previously found that GDNF facilitates dopamine release in a manner dependent on adenosine A2A receptor activation. Since motor dysfunction also involves modifications of striatal glutamatergic innervation, we now tested if GDNF and its receptor system, Ret (rearranged during transfection) and GFRα1 (GDNF family receptor alpha 1) controlled the cortico-striatal glutamatergic pathway in an A2A receptor-dependent manner. GDNF (10 ng/ml) enhanced (by ≈13%) glutamate release from rat striatal nerve endings, an effect potentiated (up to ≈ 30%) by the A2A receptor agonist CGS 21680 (10 nM) and prevented by the A2A receptor antagonist, SCH 58261 (50 nM). Triple immunocytochemical studies revealed that Ret and GFRα1 were located in 50% of rat striatal glutamatergic terminals (immunopositive for vesicular glutamate transporters-1/2), where they were found to be co-located with A2A receptors. Activation of the glutamatergic system upon in vivo electrical stimulation of the rat cortico-striatal input induced striatal Ret phosphoprylation that was prevented by pre-treatment with the A2A receptor antagonist, MSX-3 (3 mg/kg). The results provide the first functional and morphological evidence that GDNF controls cortico-striatal glutamatergic pathways in a manner largely dependent on the co-activation of adenosine A2A receptors. PMID:19141075

  4. Pharmacological receptors of nematoda as target points for action of antiparasitic drugs

    Directory of Open Access Journals (Sweden)

    Trailović Saša M.

    2010-01-01

    Full Text Available Cholinergic receptors of parasitic nematodes are one of the most important possible sites of action of antiparasitic drugs. This paper presents some of our own results of electrophysiological and pharamcological examinations of nicotinic and muscarinic receptors of nematodes, as well as data from literature on a new class of anthelmintics that act precisely on cholinergic receptors. The nicotinic acetylcholine receptor (nAChR is located on somatic muscle cells of nematodes and it is responsible for the coordination of parasite movement. Cholinomimetic anthelmintics act on this receptor, as well as acetylcholine, an endogenic neurotransmitter, but they are not sensitive to enzyme acetylcholineesterase which dissolves acetylcholine. As opposed to the nicotinic receptor of vertebra, whose structure has been examined thoroughly, the stoichiometry of the nicotinic receptor of nematodes is not completely known. However, on the grounds of knowledge acquired so far, a model has been constructed recently of the potential composition of a type of nematodes nicotinic receptor, as the site of action of anthelmintics. Based on earlier investigations, it is supposed that a conventional muscarinic receptor exists in nematodes as well, so that it can also be a new pharamocological target for the development of antinematode drugs. The latest class of synthesized anthelmintics, named aminoacetonitriles (AAD, act via the nicotinic receptor. Monepantel is the first drug from the AAD group as a most significant candidate for registration in veterinary medicine. Even though several groups of cholinomimetic anthelmintics (imiodazothiazoles, tetrahydropyrimidines, organophosphat anthelmintics have been in use in veterinary practice for many years now, it is evident that cholinergic receptors of nematodes still present an attractive place in the examinations and development of new antinematode drugs. .

  5. Regioselective synthesis and initial evaluation of a folate receptor targeted rhaponticin prodrug

    Institute of Scientific and Technical Information of China (English)

    Xu Hua Liang; Yang Sun; Lu Sha Liu; Ying Yong Zhao; Xiao Yun Hu; Jun Fan

    2012-01-01

    To improve the therapeutic effect of rhaponticin (RHA),a folate receptor (FR) targeted RHA prodrug was designed and regioselectively synthesized by utilizing a hydrophilic peptide spacer linked to folic acid (FA) via a releasable disulfide linker.A series of biological evaluation was investigated in vitro and in vivo.The positive results of biological investigations warrant further preclinical study before this novel targeted chemotherapeutic is considered for clinical investigation.

  6. Vasopressin V1 receptors contribute to hemodynamic and sympathoinhibitory responses evoked by stimulation of adenosine A2a receptors in NTS.

    Science.gov (United States)

    Scislo, Tadeusz J; O'Leary, Donal S

    2006-05-01

    Activation of adenosine A2a receptors in the nucleus of the solitary tract (NTS) decreases mean arterial pressure (MAP), heart rate (HR), and renal sympathetic nerve activity (RSNA), whereas increases in preganglionic adrenal sympathetic nerve activity (pre-ASNA) occur, a pattern similar to that observed during hypotensive hemorrhage. Central vasopressin V1 receptors may contribute to posthemorrhagic hypotension and bradycardia. Both V1 and A2a receptors are densely expressed in the NTS, and both of these receptors are involved in cardiovascular control; thus they may interact. The responses elicited by NTS A2a receptors are mediated mostly via nonglutamatergic mechanisms, possibly via release of vasopressin. Therefore, we investigated whether blockade of NTS V1 receptors alters the autonomic response patterns evoked by stimulation of NTS A2a receptors (CGS-21680, 20 pmol/50 nl) in alpha-chloralose-urethane anesthetized male Sprague-Dawley rats. In addition, we compared the regional sympathetic responses to microinjections of vasopressin (0.1-100 ng/50 nl) into the NTS. Blockade of V1 receptors reversed the normal decreases in MAP into increases (-95.6 +/- 28.3 vs. 51.4 +/- 15.7 integralDelta%), virtually abolished the decreases in HR (-258.3 +/- 54.0 vs. 18.9 +/- 57.8 integralDeltabeats/min) and RSNA (-239.3 +/- 47.4 vs. 15.9 +/- 36.1 integralDelta%), and did not affect the increases in pre-ASNA (279.7 +/- 48.3 vs. 233.1 +/- 54.1 integralDelta%) evoked by A2a receptor stimulation. The responses partially returned toward normal values approximately 90 min after the blockade. Microinjections of vasopressin into the NTS evoked dose-dependent decreases in HR and RSNA and variable MAP and pre-ASNA responses with a tendency toward increases. We conclude that the decreases in MAP, HR, and RSNA in response to NTS A2a receptor stimulation may be mediated via release of vasopressin from neural terminals in the NTS. The differential effects of NTS V1 and A2a receptors on

  7. Targeting the erythropoietin receptor on glioma cells reduces tumour growth

    Energy Technology Data Exchange (ETDEWEB)

    Peres, Elodie A.; Valable, Samuel [CERVOxy team ' Hypoxia and cerebrovascular pathophysiology' , UMR 6232 CI-NAPS, Universite de Caen Basse-Normandie, Universite Paris-Descartes, CNRS, CEA. G.I.P. CYCERON, Caen (France); Guillamo, Jean-Sebastien [CERVOxy team ' Hypoxia and cerebrovascular pathophysiology' , UMR 6232 CI-NAPS, Universite de Caen Basse-Normandie, Universite Paris-Descartes, CNRS, CEA. G.I.P. CYCERON, Caen (France); Departement de Neurologie, CHU de Caen (France); Marteau, Lena [CERVOxy team ' Hypoxia and cerebrovascular pathophysiology' , UMR 6232 CI-NAPS, Universite de Caen Basse-Normandie, Universite Paris-Descartes, CNRS, CEA. G.I.P. CYCERON, Caen (France); Bernaudin, Jean-Francois [Service d' Histologie-Biologie Tumorale, ER2UPMC, Universite Paris 6, Hopital Tenon, Paris (France); Roussel, Simon [CERVOxy team ' Hypoxia and cerebrovascular pathophysiology' , UMR 6232 CI-NAPS, Universite de Caen Basse-Normandie, Universite Paris-Descartes, CNRS, CEA. G.I.P. CYCERON, Caen (France); Lechapt-Zalcman, Emmanuele [CERVOxy team ' Hypoxia and cerebrovascular pathophysiology' , UMR 6232 CI-NAPS, Universite de Caen Basse-Normandie, Universite Paris-Descartes, CNRS, CEA. G.I.P. CYCERON, Caen (France); Service d' Anatomie Pathologique, CHU de Caen (France); Bernaudin, Myriam [CERVOxy team ' Hypoxia and cerebrovascular pathophysiology' , UMR 6232 CI-NAPS, Universite de Caen Basse-Normandie, Universite Paris-Descartes, CNRS, CEA. G.I.P. CYCERON, Caen (France); Petit, Edwige, E-mail: epetit@cyceron.fr [CERVOxy team ' Hypoxia and cerebrovascular pathophysiology' , UMR 6232 CI-NAPS, Universite de Caen Basse-Normandie, Universite Paris-Descartes, CNRS, CEA. G.I.P. CYCERON, Caen (France)

    2011-10-01

    Hypoxia has been shown to be one of the major events involved in EPO expression. Accordingly, EPO might be expressed by cerebral neoplastic cells, especially in glioblastoma, known to be highly hypoxic tumours. The expression of EPOR has been described in glioma cells. However, data from the literature remain descriptive and controversial. On the basis of an endogenous source of EPO in the brain, we have focused on a potential role of EPOR in brain tumour growth. In the present study, with complementary approaches to target EPO/EPOR signalling, we demonstrate the presence of a functional EPO/EPOR system on glioma cells leading to the activation of the ERK pathway. This EPO/EPOR system is involved in glioma cell proliferation in vitro. In vivo, we show that the down-regulation of EPOR expression on glioma cells reduces tumour growth and enhances animal survival. Our results support the hypothesis that EPOR signalling in tumour cells is involved in the control of glioma growth.

  8. Novel receptor targets for production and action of allopregnanolone in the central nervous system: a focus on pregnane xenobiotic receptor

    Directory of Open Access Journals (Sweden)

    Cheryl A Frye

    2014-04-01

    Full Text Available Neurosteroids are cholesterol-based hormones that can be produced in the brain, independent of secretion from peripheral endocrine glands, such as the gonads and adrenals. A focus in our laboratory for over 25 years has been how production of the pregnane neurosteroid, allopregnanolone, is regulated and the novel (i.e. non steroid receptor targets for steroid action for behavior. One endpoint of interest has been lordosis, the mating posture of female rodents. Allopregnanolone is necessary and sufficient for lordosis, and the brain circuitry underlying it, such as actions in the midbrain ventral tegmental area (VTA, has been well-characterized. Published and recent findings supporting a dynamic role of allopregnanolone are included in this review. First, contributions of ovarian and adrenal sources of precursors of allopregnanolone, and the requisite enzymatic actions for de novo production in the central nervous system will be discussed. Second, how allopregnanolone produced in the brain has actions on behavioral processes that are independent of binding to steroid receptors, but instead involve rapid modulatory actions via neurotransmitter targets (e.g. -amino butyric acid-GABA, n-methyl-D-aspartate- NMDA will be reviewed. Third, a recent focus on characterizing the role of a promiscuous nuclear receptor, pregnane xenobiotic receptor (PXR, involved in cholesterol metabolism and expressed in the VTA, as a target for allopregnanolone and how this relates to both actions and production of allopregnanolone will be addressed. For example, allopregnanolone can bind PXR and knocking down expression of PXR in the midbrain VTA attenuates actions of allopregnanolone via NMDA and/or GABAA for lordosis. Our understanding of allopregnanolone’s actions in the VTA for lordosis has been extended to reveal the role of allopregnanolone for broader, clinically-relevant questions, such as neuropsychiatric disorders, epilepsy, and aging.

  9. Regulation of epithelial sodium channel a-subunit expression by adenosine receptor A2a in alveolar epithelial cells

    Institute of Scientific and Technical Information of China (English)

    DENG Wang; WANG Dao-xin; ZHANG Wei; LI Chang-yi

    2011-01-01

    Background The amiloride-sensitive epithelial sodium channel a-subunit (a-ENaC) is an important factor for alveolar fluid clearance during acute lung injury. The relationship between adenosine receptor A2a (A2aAR) expressed in alveolar epithelial cells and aα-ENaC is poorly understood. We targeted the A2aAR in this study to investigate its role in the expression of αa-ENaC and in acute lung injury.Methods A549 cells were incubated with different concentrations of A2aAR agonist CGS-21680 and with 100 μmol/L CGS-21680 for various times. Rats were treated with lipopolysaccharide (LPS) after CGS-21680 was injected. Animals were sacrificed and tissue was harvested for evaluation of lung injury by analysis of the lung wet-to-dry weight ratio, lung permeability and myeloperoxidase activity. RT-PCR and Western blotting were used to determine the mRNA and protein expression levels of α-ENaC in A549 cells and alveolar type II epithelial cells.Results Both mRNA and protein levels of α-ENaC were markedly higher from 4 hours to 24 hours after exposure to 100μmol/L CGS-21680. There were significant changes from 0.1 umol/L to 100 μmol/L CGS-21680, with a positive correlation between increased concentrations of CGS-21680 and expression of α-ENaC. Treatment with CGS-21680during LPS induced lung injury protected the lung and promoted α-ENaC expression in the alveolar epithelial cells.Conclusion Activation of A2aAR has a protective effect during the lung injury, which may be beneficial to the prognosis of acute lung injury.

  10. Growth factor receptors and related signalling pathways as targets for novel treatment strategies of hepatocellular cancer

    Institute of Scientific and Technical Information of China (English)

    Michael Hopfner; Detlef Schuppan; Hans Scherübl

    2008-01-01

    Growth factors and their corresponding receptors are commonly overexpressed and/or dysregulated in many cancers including hepatocellular cancer (HCC). Clinical trials indicate that growth factor receptors and their related signalling pathways play important roles in HCC cancer etiology and progression, thus providing rational targets for innovative cancer therapies. A number of strategies including monoclonal antibodies, tyrosine kinase inhibitors ("small molecule inhibitors") and antisense oligonucleotides have already been evaluated for their potency to inhibit the activity and downstream signalling cascades of these receptors in HCC. First clinical trials have also shown that multi-kinase inhibition is an effective novel treatment strategy in HCC. In this respect sorafenib, an inhibitor of Raf-, VEGF- and PDGF-signalling, is the first multi-kinase inhibitor that has been approved by the FDA for the treatment of advanced HCC. Moreover, the serine-threonine kinase of mammalian target of rapamycin (mTOR) upon which the signalling of several growth factor receptors converge plays a central role in cancer cell proliferation, mTOR inhibition of HCC is currently also being studied in preclinical trials. As HCCs represent hypervascularized neoplasms, inhibition of tumour vessel formation via interfering with the VEGF/VEGFR system is another promising approach in HCC treatment. This review will summarize the current status of the various growth factor receptor-based treatment strategies and in view of the multitude of novel targeted approaches, the rationale for combination therapies for advanced HCC treatment will also be taken into account.

  11. The sphingosine-1-phosphate receptor: A novel therapeutic target for multiple sclerosis and other autoimmune diseases.

    Science.gov (United States)

    Mao-Draayer, Yang; Sarazin, Jeffrey; Fox, David; Schiopu, Elena

    2017-02-01

    Multiple sclerosis (MS) is a prototype autoimmune disease of the central nervous system (CNS). Currently, there is no drug that provides a cure for MS. To date, all immunotherapeutic drugs target relapsing remitting MS (RR-MS); it remains a daunting medical challenge in MS to develop therapy for secondary progressive MS (SP-MS). Since the approval of the non-selective sphingosine-1-phosphate (S1P) receptor modulator FTY720 (fingolimod [Gilenya®]) for RR-MS in 2010, there have been many emerging studies with various selective S1P receptor modulators in other autoimmune conditions. In this article, we will review how S1P receptor may be a promising therapeutic target for SP-MS and other autoimmune diseases such as psoriasis, polymyositis and lupus.

  12. Lanreotide-conjugated PEG-DSPE micelles: an efficient nanocarrier targeting to somatostatin receptor positive tumors.

    Science.gov (United States)

    Zheng, Nan; Dai, Wenbing; Zhang, Hua; Wang, Xueqing; Wang, Jiancheng; Zhang, Xuan; Wang, Kun; Li, Jian; Zhang, Qiang

    2015-01-01

    Lanreotide is an octapeptide analog of endogenous somatostatin, specifically binding with tumors over-express somatostatin receptor 2 (SSTR2). In this study, we conjugated lanreotide to 1, 2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy (poly-(ethylene glycol))-2000] (PEG-DSPE), constructed active targeted micelles (lanreotide-PM), characterized their in vitro and in vivo targeting effect, and explored the receptor mediated transportion. The uptake of lanreotide-PM was found to be related to the expression level of SSTR2 in different cell lines and the competitive inhibition phenomenon indicated that the cellular uptake of lanreotide-PM was via a receptor meditated mechanism. In vivo, more lanreotide-PM accumulated in SSTR2 high expression tumor xenografts, endocytosed by the tumor cells, induced more apoptosis of tumor cells, and suppressed tumor growth efficiently. In conclusion, lanreotide-modified micelles containing antitumor drugs provide a promising strategy for the treatment of SSTR-expressing tumors.

  13. Targeting Receptors, Transporters and Site of Absorption to Improve Oral Drug Delivery

    Directory of Open Access Journals (Sweden)

    J.H. Hamman

    2007-01-01

    Full Text Available Although the oral route of drug administration is the most acceptable way of self-medication with a high degree of patient compliance, the intestinal absorption of many drugs is severely hampered by different biological barriers. These barriers comprise of biochemical and physical components. The biochemical barrier includes enzymatic degradation in the gastrointestinal lumen, brush border and in the cytoplasm of the epithelial cells as well as efflux transporters that pump drug molecules from inside the epithelial cell back to the gastrointestinal lumen. The physical barrier consists of the epithelial cell membranes, tight junctions and mucus layer. Different strategies have been applied to improve the absorption of drugs after oral administration, which range from chemical modification of drug molecules and formulation technologies to the targeting of receptors, transporters and specialized cells such as the gut-associated lymphoid tissues. This review focuses specifically on the targeting of receptor-mediated endocytosis, transporters and the absorption-site as methods of optimizing intestinal drug absorption. Intestinal epithelial cells express several nutrient transporters that can be targeted by modifying the drug molecule in such a way that it is recognized as a substrate. Receptor-mediated endocytosis is a transport mechanism that can be targeted for instance by linking a receptor substrate to the drug molecule of interest. Many formulation strategies exist for enhancing drug absorption of which one is to deliver drugs at a specific site in the gastrointestinal tract where optimum drug absorption takes place.

  14. Targeting receptors, transporters and site of absorption to improve oral drug delivery.

    Science.gov (United States)

    Hamman, J H; Demana, P H; Olivier, E I

    2007-01-01

    Although the oral route of drug administration is the most acceptable way of self-medication with a high degree of patient compliance, the intestinal absorption of many drugs is severely hampered by different biological barriers. These barriers comprise of biochemical and physical components. The biochemical barrier includes enzymatic degradation in the gastrointestinal lumen, brush border and in the cytoplasm of the epithelial cells as well as efflux transporters that pump drug molecules from inside the epithelial cell back to the gastrointestinal lumen. The physical barrier consists of the epithelial cell membranes, tight junctions and mucus layer. Different strategies have been applied to improve the absorption of drugs after oral administration, which range from chemical modification of drug molecules and formulation technologies to the targeting of receptors, transporters and specialized cells such as the gut-associated lymphoid tissues. This review focuses specifically on the targeting of receptor-mediated endocytosis, transporters and the absorption-site as methods of optimizing intestinal drug absorption. Intestinal epithelial cells express several nutrient transporters that can be targeted by modifying the drug molecule in such a way that it is recognized as a substrate. Receptor-mediated endocytosis is a transport mechanism that can be targeted for instance by linking a receptor substrate to the drug molecule of interest. Many formulation strategies exist for enhancing drug absorption of which one is to deliver drugs at a specific site in the gastrointestinal tract where optimum drug absorption takes place.

  15. Muscarinic receptors on airway mesenchymal cells : Novel findings for an ancient target

    NARCIS (Netherlands)

    Meurs, Herman; Dekkers, Bart G. J.; Maarsingh, Harm; Halayko, Andrew J.; Zaagsma, Johan; Gosens, Reinoud

    2013-01-01

    Since ancient times, anticholinergics have been used as a bronchodilator therapy for obstructive lung diseases. Targets of these drugs are G-protein-coupled muscarinic M-1, M-2 and M-3 receptors in the airways, which have long been recognized to regulate vagally-induced airway smooth muscle contract

  16. GHB receptor targets in the CNS: Focus on high-affinity binding sites

    DEFF Research Database (Denmark)

    Bay, Tina; Eghorn, Laura Friis; Klein, Anders Bue;

    2014-01-01

    γ-Hydroxybutyric acid (GHB) is an endogenous compound in the mammalian brain with both low- and high-affinity receptor targets. GHB is used clinically in the treatment of symptoms of narcolepsy and alcoholism, but also illicitly abused as the recreational drug Fantasy. Major pharmacological effects...

  17. Generalization of a targeted library design protocol: application to 5-HT7 receptor ligands.

    Science.gov (United States)

    Nordling, Erik; Homan, Evert

    2004-01-01

    Herein a general concept for the design of targeted libraries for proteins with binding sites that are divided into subsites is laid out, including several practical aspects and their solutions. The design is based on a chemogenomic classification of the subsites followed by collection of bioactive molecular fragments and virtual library generation. The general process is outlined and applied to the assembly of a library of 500 molecules targeting the serotonin type 7 (5-HT7) receptor, a class A G-Protein Coupled Receptor (GPCR). Utilizing commercially available building blocks of similar size and composition, a reference library was created. Control sets of known ligands for the 5-HT7 receptor, other GPCRs, and nuclear receptors were collected from literature sources. Principal component analysis of molecular descriptors for the two libraries and the literature sets, displayed a focusing of the targeted library to the region in the chemical space defined by the literature actives, suggesting a denser coverage of the bioactive region than for the more diverse reference library. Additional computational validations, including PCA class predictions, 3D pharmacophore modeling, and docking calculations all indicated an enrichment factor of 5-HT7 ligand-like molecules in the range of 2-4 for the targeted library compared to the reference library.

  18. Targeting the Estrogen Receptor for Ubiquitination and Degradation in Breast Cancer Cells

    Science.gov (United States)

    2004-10-01

    equipment and microscope. We are also grateful to Frank Mercurio (Signal Division, Celgene Pharmaceuticals, Wan-en, NJ) for help obtaining GA-1-mo...34Targeting the estrogen receptor for Proteolysis", wifli Celgene , hic. ($40,000), K Sakamoto, P.I. 1/02-12/02 CaPCURE research award

  19. Theranostic Value of Multimers: Lessons Learned from Trimerization of Neurotensin Receptor Ligands and Other Targeting Vectors

    Directory of Open Access Journals (Sweden)

    Simone Maschauer

    2017-03-01

    Full Text Available Neurotensin receptor 1 (NTS1 is overexpressed on a variety of cancer entities; for example, prostate cancer, ductal pancreatic adenocarcinoma, and breast cancer. Therefore, it represents an interesting target for the diagnosis of these cancers types by positron emission tomography (PET [...

  20. Epidermal Growth Factor Receptor targeting in non-small cell lung cancer: revisiting different strategies against the same target.

    Science.gov (United States)

    Castañón, Eduardo; Martín, Patricia; Rolfo, Christian; Fusco, Juan P; Ceniceros, Lucía; Legaspi, Jairo; Santisteban, Marta; Gil-Bazo, Ignacio

    2014-01-01

    Epidermal Growth Factor Receptor (EGFR) tyrosine kinase inhibitors (TKIs) have changed the paradigm of treatment in non-small cell lung cancer (NSCLC). The molecular biology study of EGFR has led to clinical trials that select patients more accurately, regarding the presence of EGFR activating mutations. Nonetheless, a lack of response or a temporary condition of the response has been detected in patients on EGFR TKIs. This has urged to study potential resistance mechanisms underneath. The most important ones are the presence of secondary mutations in EGFR, such as T790M, or the overexpression of mesenchymal-epithelial transition factor (MET) that may explain why patients who initially respond to EGFR TKIs, may ultimately become refractory. Several approaches have been taken and new drugs both targeting EGFR resistance-mutation or MET are currently being developed. Here we review and update the EGFR biological pathway as well as the clinical data leading to approval of the EGFR TKIs currently in the market. New compounds under investigation targeting resistance mutations or dually targeting EGFR and other relevant receptors are also reviewed and discussed.

  1. CONSTITUTIVE ANDROSTANE RECEPTOR DEPENDENT AND INDEPENDENT MODULATION OF CYP3A2, CYP1A2 BY PHENOBARBITAL AND FIBRATE IN RATS’ LIVER

    Directory of Open Access Journals (Sweden)

    Zein Shaban Ibrahim

    2013-01-01

    Full Text Available Cytochrome P450 enzymes, CYP3A and CYP1A are major drug metabolizing enzymes in the liver. CYP3A enzymes have a major role in the metabolism of 30-40% of all used drugs. CYP1A2 is a key enzyme having an important role in the metabolic clearance of 5% of currently marketed drugs. CYP1A2 participates in the metabolic activation of chemical mutagens in cooked food, therefore its activity is suspected to be one of the possible risk factors determining the carcinogenicity of heterocyclic amines in human beings. In a previous report, we have reported the induction of CYP3A2 and the inhibition of CYP1A2 by Fibrate (CFA and proved CYP1A2 inhibition to be PPARα-dependent. CYP3A2 and CYP1A2 have been reported to be induced in the liver by Phenobarbital (PB while Fibrates was reported to induce CYP3A2. However the exact mechanism of the induction of CYP3A2 by CFA and PB and induction of CYP1A2 by PB has not been clarified yet whether it is through Constitutive Androstane Receptor (CAR or other receptor as PPARα or Pregnane X Receptor (PXR. We treated Wistar female rats (with normal expression of CAR protein and Wistar femal Kyoto rats (with low expression of CAR protein with PB and Clofibric Acid (CFA. PB caused a high CYP3A2 induction in Wistar female rats and a low induction in (WKY indicating that PB induced CYP3A2 in a CAR-dependent manner. Interestingly, PB treatment induced CYP1A2 in Wistar female rats and failed to induce it in (WKY indicating that the induction of CYP1A2 by PB to be CAR-dependent. Moreover CFA induced CYP3A2 protein similarly in both rat strains indicating that CYP3A2 induction by Fibrates is CAR-independent and most probably to be PXR or PPARα-dependent. For the best of our knowledge this is the first report that shows a clear evidence of the CAR-dependent induction of CYP1A2 and CYP3A2 by PB and the CAR-independent induction of CYP3A2 by fibrates.

  2. Integrating Pharmacophore into Membrane Molecular Dynamics Simulations to Improve Homology Modeling of G Protein-coupled Receptors with Ligand Selectivity: A2A Adenosine Receptor as an Example.

    Science.gov (United States)

    Zeng, Lingxiao; Guan, Mengxin; Jin, Hongwei; Liu, Zhenming; Zhang, Liangren

    2015-12-01

    Homology modeling has been applied to fill in the gap in experimental G protein-coupled receptors structure determination. However, achievement of G protein-coupled receptors homology models with ligand selectivity remains challenging due to structural diversity of G protein-coupled receptors. In this work, we propose a novel strategy by integrating pharmacophore and membrane molecular dynamics (MD) simulations to improve homology modeling of G protein-coupled receptors with ligand selectivity. To validate this integrated strategy, the A2A adenosine receptor (A2A AR), whose structures in both active and inactive states have been established, has been chosen as an example. We performed blind predictions of the active-state A2A AR structure based on the inactive-state structure and compared the performance of different refinement strategies. The blind prediction model combined with the integrated strategy identified ligand-receptor interactions and conformational changes of key structural elements related to the activation of A2 A AR, including (i) the movements of intracellular ends of TM3 and TM5/TM6; (ii) the opening of ionic lock; (iii) the movements of binding site residues. The integrated strategy of pharmacophore with molecular dynamics simulations can aid in the optimization in the identification of side chain conformations in receptor models. This strategy can be further investigated in homology modeling and expand its applicability to other G protein-coupled receptor modeling, which should aid in the discovery of more effective and selective G protein-coupled receptor ligands. © 2015 John Wiley & Sons A/S.

  3. Targeted chemotherapy for triple-negative breast cancers via LHRH receptor.

    Science.gov (United States)

    Föst, Crispin; Duwe, Francesca; Hellriegel, Martin; Schweyer, Stefan; Emons, Günter; Gründker, Carsten

    2011-05-01

    Triple-negative breast cancer does not express estrogen and progesterone receptors and there is no overexpression/amplification of the HER2-neu gene. Therefore, this subtype of breast cancer lacks the benefits of specific therapies which target these receptors. About 60% of all human breast cancers express receptors for luteinizing hormone releasing hormone (LHRH, GnRH), which might be used as a target. The LHRH receptor can be used for targeted chemotherapy with cytotoxic luteinizing hormone releasing hormone agonists such as AEZS-108 (AN-152), in which doxorubicin is linked to [D-Lys6]LHRH. In the present study we have analyzed by in vitro and in vivo experiments whether the cytotoxic LHRH agonist AEZS-108 (AN-152) induces apoptosis in triple-negative human breast cancer cells that express LHRH receptors. LHRH receptor expression in tumor biopsy specimens of triple-negative breast cancers was tested using immunohistochemistry. Cell proliferation was analyzed using alamar blue proliferation assay. Induction of apoptosis was quantified by measurement of loss of mitochondrial membrane potential. In vivo experiments were performed using nude mice bearing xenografted human breast tumors.Thirty-one of 42 triple-negative breast cancers (73.8%) expressed LHRH receptors. We could show that treatment of triple-negative but LHRH-positive MDA-MB-231, HCC1806 and HCC1937 human breast cancer cells with AEZS-108 (AN-152) resulted in apoptotic cell death in vitro via activation of caspase-3. The antitumor effects were confirmed in nude mice. AEZS-108 (AN-152) inhibited the growth of xenotransplants of triple-negative human breast cancers in nude mice completely, without any apparent side effects. The cytotoxic LHRH agonist AEZS-108 (AN-152) seems to be a suitable drug for an efficacious therapy for triple-negative breast cancers with little toxicity.

  4. CC-chemokine receptors: a potential therapeutic target for Trypanosoma cruzi-elicited myocarditis.

    Science.gov (United States)

    Marino, A P M P; Silva, A A; Santos, P V A; Pinto, L M O; Gazinelli, R T; Teixeira, M M; Lannes-Vieira, J

    2005-03-01

    The comprehension of the pathogenesis of Trypanosoma cruzi-elicited myocarditis is crucial to delineate new therapeutic strategies aiming to ameliorate the inflammation that leads to heart dysfunction, without hampering parasite control. The augmented expression of CCL5/RANTES and CCL3/MIP-1alpha, and their receptor CCR5, in the heart of T. cruzi-infected mice suggests a role for CC-chemokines and their receptors in the pathogenesis of T. cruzi-elicited myocarditis. Herein, we discuss our recent results using a CC-chemokine receptor inhibitor (Met-RANTES), showing the participation of CC-chemokines in T. cruzi infection and unraveling CC-chemokine receptors as an attractive therapeutic target for further evaluation in Chagas disease.

  5. CC-chemokine receptors: a potential therapeutic target for Trypanosoma cruzi-elicited myocarditis

    Directory of Open Access Journals (Sweden)

    APMP Marino

    2005-03-01

    Full Text Available The comprehension of the pathogenesis of Trypanosoma cruzi-elicited myocarditis is crucial to delineate new therapeutic strategies aiming to ameliorate the inflammation that leads to heart dysfunction, without hampering parasite control. The augmented expression of CCL5/RANTES and CCL3/MIP-1alpha, and their receptor CCR5, in the heart of T. cruzi-infected mice suggests a role for CC-chemokines and their receptors in the pathogenesis of T. cruzi-elicited myocarditis. Herein, we discuss our recent results using a CC-chemokine receptor inhibitor (Met-RANTES, showing the participation of CC-chemokines in T. cruzi infection and unraveling CC-chemokine receptors as an attractive therapeutic target for further evaluation in Chagas disease.

  6. Putative Biomarkers and Targets of Estrogen Receptor Negative Human Breast Cancer

    Directory of Open Access Journals (Sweden)

    Stephen W. Byers

    2011-07-01

    Full Text Available Breast cancer is a progressive and potentially fatal disease that affects women of all ages. Like all progressive diseases, early and reliable diagnosis is the key for successful treatment and annihilation. Biomarkers serve as indicators of pathological, physiological, or pharmacological processes. Her2/neu, CA15.3, estrogen receptor (ER, progesterone receptor (PR, and cytokeratins are biomarkers that have been approved by the Food and Drug Administration for disease diagnosis, prognosis, and therapy selection. The structural and functional complexity of protein biomarkers and the heterogeneity of the breast cancer pathology present challenges to the scientific community. Here we review estrogen receptor-related putative breast cancer biomarkers, including those of putative breast cancer stem cells, a minor population of estrogen receptor negative tumor cells that retain the stem cell property of self renewal. We also review a few promising cytoskeleton targets for ER alpha negative breast cancer.

  7. Eicosanoid receptors: Targets for the treatment of disrupted intestinal epithelial homeostasis.

    Science.gov (United States)

    Moreno, Juan J

    2017-02-05

    The importance of cyclooxygenase and lipoxygenase pathways and the consequent eicosanoid synthesis in the physiology and pathophysiology of the intestinal epithelium is currently being established. Each eicosanoid (prostanoid, leukotriene, hydroxyeicosatetraenoic acid) preferentially recognizes one or more receptors coupled to one or more signal-transduction processes. This overview focuses on the role of eicosanoid receptors in the maintenance of intestinal epithelium physiology through the control of proliferation/differentiation/apoptosis processes. Furthermore, it is reported that the role of these receptors on the regulation of the barrier function of the intestinal epithelium have arisen through the regulation of absorption/secretion processes, tight-junction state and the control of the intestinal immune response. Also, this review considers the implication of AA cascade in the disruption of epithelial homeostasis during inflammatory bowel diseases and colorectal cancer as well as the therapeutic values and potential of the eicosanoid receptors as novel targets for the treatments of the pathologies above mentioned.

  8. Drug addiction: targeting dynamic neuroimmune receptor interactions as a potential therapeutic strategy.

    Science.gov (United States)

    Jacobsen, Jonathan Henry W; Hutchinson, Mark R; Mustafa, Sanam

    2016-02-01

    Drug addiction and dependence have proven to be difficult psychiatric disorders to treat. The limited efficacy of neuronally acting medications, such as acamprosate and naltrexone, highlights the need to identify novel targets. Recent research has underscored the importance of the neuroimmune system in many behavioural manifestations of drug addiction. In this review, we propose that our appreciation for complex phenotypes such as drug addiction and dependence will come with a greater understanding that these disorders are the result of intricate, interconnected signalling pathways that are, if only partially, determined at the receptor level. The idea of receptor heteromerisation and receptor mosaics will be introduced to explain cross talk between the receptors and signalling molecules implicated in neuroimmune signalling pathways. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Targeting neurotransmitter receptors with nanoparticles in vivo allows single-molecule tracking in acute brain slices

    Science.gov (United States)

    Varela, Juan A.; Dupuis, Julien P.; Etchepare, Laetitia; Espana, Agnès; Cognet, Laurent; Groc, Laurent

    2016-03-01

    Single-molecule imaging has changed the way we understand many biological mechanisms, particularly in neurobiology, by shedding light on intricate molecular events down to the nanoscale. However, current single-molecule studies in neuroscience have been limited to cultured neurons or organotypic slices, leaving as an open question the existence of fast receptor diffusion in intact brain tissue. Here, for the first time, we targeted dopamine receptors in vivo with functionalized quantum dots and were able to perform single-molecule tracking in acute rat brain slices. We propose a novel delocalized and non-inflammatory way of delivering nanoparticles (NPs) in vivo to the brain, which allowed us to label and track genetically engineered surface dopamine receptors in neocortical neurons, revealing inherent behaviour and receptor activity regulations. We thus propose a NP-based platform for single-molecule studies in the living brain, opening new avenues of research in physiological and pathological animal models.

  10. Autotaxin and LPA receptors represent potential molecular targets for the radiosensitization of murine glioma through effects on tumor vasculature.

    Directory of Open Access Journals (Sweden)

    Stephen M Schleicher

    Full Text Available Despite wide margins and high dose irradiation, unresectable malignant glioma (MG is less responsive to radiation and is uniformly fatal. We previously found that cytosolic phospholipase A2 (cPLA(2 is a molecular target for radiosensitizing cancer through the vascular endothelium. Autotaxin (ATX and lysophosphatidic acid (LPA receptors are downstream from cPLA(2 and highly expressed in MG. Using the ATX and LPA receptor inhibitor, α-bromomethylene phosphonate LPA (BrP-LPA, we studied ATX and LPA receptors as potential molecular targets for the radiosensitization of tumor vasculature in MG. Treatment of Human Umbilical Endothelial cells (HUVEC and mouse brain microvascular cells bEND.3 with 5 µmol/L BrP-LPA and 3 Gy irradiation showed decreased clonogenic survival, tubule formation, and migration. Exogenous addition of LPA showed radioprotection that was abrogated in the presence of BrP-LPA. In co-culture experiments using bEND.3 and mouse GL-261 glioma cells, treatment with BrP-LPA reduced Akt phosphorylation in both irradiated cell lines and decreased survival and migration of irradiated GL-261 cells. Using siRNA to knock down LPA receptors LPA1, LPA2 or LPA3 in HUVEC, we demonstrated that knockdown of LPA2 but neither LPA1 nor LPA3 led to increased viability and proliferation. However, knockdown of LPA1 and LPA3 but not LPA2 resulted in complete abrogation of tubule formation implying that LPA1 and LPA3 on endothelial cells are likely targets of BrP-LPA radiosensitizing effect. Using heterotopic tumor models of GL-261, mice treated with BrP-LPA and irradiation showed a tumor growth delay of 6.8 days compared to mice treated with irradiation alone indicating that inhibition of ATX and LPA receptors may significantly improve malignant glioma response to radiation therapy. These findings identify ATX and LPA receptors as molecular targets for the development of radiosensitizers for MG.

  11. EGFR and EphA2 are host factors for hepatitis C virus entry and possible targets for antiviral therapy.

    Science.gov (United States)

    Lupberger, Joachim; Zeisel, Mirjam B; Xiao, Fei; Thumann, Christine; Fofana, Isabel; Zona, Laetitia; Davis, Christopher; Mee, Christopher J; Turek, Marine; Gorke, Sebastian; Royer, Cathy; Fischer, Benoit; Zahid, Muhammad N; Lavillette, Dimitri; Fresquet, Judith; Cosset, François-Loïc; Rothenberg, S Michael; Pietschmann, Thomas; Patel, Arvind H; Pessaux, Patrick; Doffoël, Michel; Raffelsberger, Wolfgang; Poch, Olivier; McKeating, Jane A; Brino, Laurent; Baumert, Thomas F

    2011-05-01

    Hepatitis C virus (HCV) is a major cause of liver disease, but therapeutic options are limited and there are no prevention strategies. Viral entry is the first step of infection and requires the cooperative interaction of several host cell factors. Using a functional RNAi kinase screen, we identified epidermal growth factor receptor and ephrin receptor A2 as host cofactors for HCV entry. Blocking receptor kinase activity by approved inhibitors broadly impaired infection by all major HCV genotypes and viral escape variants in cell culture and in a human liver chimeric mouse model in vivo. The identified receptor tyrosine kinases (RTKs) mediate HCV entry by regulating CD81-claudin-1 co-receptor associations and viral glycoprotein-dependent membrane fusion. These results identify RTKs as previously unknown HCV entry cofactors and show that tyrosine kinase inhibitors have substantial antiviral activity. Inhibition of RTK function may constitute a new approach for prevention and treatment of HCV infection.

  12. L-DOPA-treatment in primates disrupts the expression of A(2A) adenosine-CB(1) cannabinoid-D(2) dopamine receptor heteromers in the caudate nucleus.

    Science.gov (United States)

    Bonaventura, Jordi; Rico, Alberto J; Moreno, Estefanía; Sierra, Salvador; Sánchez, Marta; Luquin, Natasha; Farré, Daniel; Müller, Christa E; Martínez-Pinilla, Eva; Cortés, Antoni; Mallol, Josefa; Armentero, Marie-Therese; Pinna, Annalisa; Canela, Enric I; Lluís, Carme; McCormick, Peter J; Lanciego, José L; Casadó, Vicent; Franco, Rafael

    2014-04-01

    The molecular basis of priming for L-DOPA-induced dyskinesias in Parkinson's disease (PD), which depends on the indirect pathway of motor control, is not known. In rodents, the indirect pathway contains striatopallidal GABAergic neurons that express heterotrimers composed of A(2A) adenosine, CB(1) cannabinoid and D(2) dopamine receptors that regulate dopaminergic neurotransmission. The present study was designed to investigate the expression of these heteromers in the striatum of a primate model of Parkinson's disease and to determine whether their expression and pharmacological properties are altered upon L-DOPA treatment. By using the recently developed in situ proximity ligation assay and by identification of a biochemical fingerprint, we discovered a regional distribution of A(2A)/CB(1) /D(2) receptor heteromers that predicts differential D(2)-mediated neurotransmission in the caudate-putamen of Macaca fascicularis. Whereas heteromers were abundant in the caudate nucleus of both naïve and MPTP-treated monkeys, L-DOPA treatment blunted the biochemical fingerprint and led to weak heteromer expression. These findings constitute the first evidence of altered receptor heteromer expression in pathological conditions and suggest that drugs targeting A(2A)-CB(1) -D(2) receptor heteromers may be successful to either normalize basal ganglia output or prevent L-DOPA-induced side effects. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. Arginine 199 and leucine 208 have key roles in the control of adenosine A2A receptor signalling function.

    Directory of Open Access Journals (Sweden)

    Nicolas Bertheleme

    Full Text Available One successful approach to obtaining high-resolution crystal structures of G-protein coupled receptors is the introduction of thermostabilising mutations within the receptor. This technique allows the generation of receptor constructs stabilised into different conformations suitable for structural studies. Previously, we functionally characterised a number of mutants of the adenosine A2A receptor, thermostabilised either in an agonist or antagonist conformation, using a yeast cell growth assay and demonstrated that there is a correlation between thermostability and loss of constitutive activity. Here we report the functional characterisation of 30 mutants intermediate between the Rag23 (agonist conformation mutant and the wild-type receptor using the same yeast signalling assay with the aim of gaining greater insight into the role individual amino acids have in receptor function. The data showed that R199 and L208 have important roles in receptor function; substituting either of these residues for alanine abolishes constitutive activity. In addition, the R199A mutation markedly reduces receptor potency while L208A reduces receptor efficacy. A184L and L272A mutations also reduce constitutive activity and potency although to a lesser extent than the R199A and L208A. In contrast, the F79A mutation increases constitutive activity, potency and efficacy of the receptor. These findings shed new light on the role individual residues have on stability of the receptor and also provide some clues as to the regions of the protein responsible for constitutive activity. Furthermore, the available adenosine A2A receptor structures have allowed us to put our findings into a structural context.

  14. Selective adenosine A2A receptor agonists and antagonists protect against spinal cord injury through peripheral and central effects

    Directory of Open Access Journals (Sweden)

    Esposito Emanuela

    2011-04-01

    Full Text Available Abstract Background Permanent functional deficits following spinal cord injury (SCI arise both from mechanical injury and from secondary tissue reactions involving inflammation. Enhanced release of adenosine and glutamate soon after SCI represents a component in the sequelae that may be responsible for resulting functional deficits. The role of adenosine A2A receptor in central ischemia/trauma is still to be elucidated. In our previous studies we have demonstrated that the adenosine A2A receptor-selective agonist CGS21680, systemically administered after SCI, protects from tissue damage, locomotor dysfunction and different inflammatory readouts. In this work we studied the effect of the adenosine A2A receptor antagonist SCH58261, systemically administered after SCI, on the same parameters. We investigated the hypothesis that the main action mechanism of agonists and antagonists is at peripheral or central sites. Methods Spinal trauma was induced by extradural compression of SC exposed via a four-level T5-T8 laminectomy in mouse. Three drug-dosing protocols were utilized: a short-term systemic administration by intraperitoneal injection, a chronic administration via osmotic minipump, and direct injection into the spinal cord. Results SCH58261, systemically administered (0.01 mg/kg intraperitoneal. 1, 6 and 10 hours after SCI, reduced demyelination and levels of TNF-α, Fas-L, PAR, Bax expression and activation of JNK mitogen-activated protein kinase (MAPK 24 hours after SCI. Chronic SCH58261 administration, by mini-osmotic pump delivery for 10 days, improved the neurological deficit up to 10 days after SCI. Adenosine A2A receptors are physiologically expressed in the spinal cord by astrocytes, microglia and oligodendrocytes. Soon after SCI (24 hours, these receptors showed enhanced expression in neurons. Both the A2A agonist and antagonist, administered intraperitoneally, reduced expression of the A2A receptor, ruling out the possibility that the

  15. The succinate receptor as a novel therapeutic target for oxidative and metabolic stress-related conditions.

    Directory of Open Access Journals (Sweden)

    Ana Carolina eAriza

    2012-02-01

    Full Text Available The succinate receptor (also known as GPR91 is a G protein-coupled receptor that is closely related to the family of P2Y purinoreceptors. It is expressed in a variety of tissues, including blood cells, adipose tissue, the liver, retina and kidney. In these tissues, this receptor and its ligand succinate have recently emerged as novel mediators in local stress situations, including ischemia, hypoxia, toxicity and hyperglycemia. Amongst others, the succinate receptor is involved in recruitment of immune cells to transplanted tissues. Moreover, it was shown to play a key role in the development of diabetic retinopathy. However, most prominently, the role of locally increased succinate levels and succinate receptor activation in the kidney, stimulating the systemic and local renin-angiotensin system, starts to unfold: The succinate receptor is a key mediator in the development of hypertension and possibly fibrosis in diabetes mellitus and metabolic syndrome. This makes the succinate receptor a promising drug target to counteract or prevent cardiovascular and fibrotic defects in these expanding disorders. Recent development of SUCNR1-specific antagonists opens novel possibilities for research in models for these disorders and may eventually provide novel opportunities for the treatment of patients.

  16. Targeting NK-1 Receptors to Prevent and Treat Pancreatic Cancer: A New Therapeutic Approach

    Energy Technology Data Exchange (ETDEWEB)

    Muñoz, Miguel, E-mail: mmunoz@cica.es [Research Laboratory on Neuropeptides (IBIS), Virgen del Rocío University Hospital, 41013 Sevilla (Spain); Coveñas, Rafael [Laboratory of Neuroanatomy of the Peptidergic System (Lab. 14), Institute of Neurosciences of Castilla y León (INCYL), University of Salamanca, 37008 Salamanca (Spain)

    2015-07-06

    Pancreatic cancer (PC) is the fourth leading cause of cancer related-deaths in both men and women, and the 1- and 5-year relative survival rates are 25% and 6%, respectively. It is known that smoking, alcoholism and psychological stress are risk factors that can promote PC and increase PC progression. To date, the prevention of PC is crucial because there is no curative treatment. After binding to the neurokinin-1 (NK-1) receptor (a receptor coupled to the stimulatory G-protein Gαs that activates adenylate cyclase), the peptide substance P (SP)—at high concentrations—is involved in many pathophysiological functions, such as depression, smoking, alcoholism, chronic inflammation and cancer. It is known that PC cells and samples express NK-1 receptors; that the NK-1 receptor is overexpressed in PC cells in comparison with non-tumor cells, and that nanomolar concentrations of SP induce PC cell proliferation. By contrast, NK-1 receptor antagonists exert antidepressive, anxiolytic and anti-inflammatory effects and anti-alcohol addiction. These antagonists also exert an antitumor action since in vitro they inhibit PC cell proliferation (PC cells death by apoptosis), and in a xenograft PC mouse model they exert both antitumor and anti-angiogenic actions. NK-1 receptor antagonists could be used for the treatment of PC and hence the NK-1 receptor could be a new promising therapeutic target in PC.

  17. Targeting of Peptide Cytotoxins to LHRH Receptors For Treatment of Cancer.

    Science.gov (United States)

    Engel, Jorg B; Tinneberg, Hans-Rudolf; Rick, Ferenc G; Berkes, Enniko; Schally, Andrew V

    2016-01-01

    Receptors for LHRH (luteinizing hormone-releasing hormone) are expressed in about 80% of human endometrial, ovarian and prostate cancers and are also found in more than 50% of breast cancers including triple negative breast cancers. In the human body, LHRH receptors are found at significant levels in the pituitary and reproductive organs. Other benign tissues or hematopoietic stem cells express only low levels of receptors for LHRH or no receptors. Thus LHRH receptors are promising targets for a receptor- mediated chemotherapy with cytotoxic hybrid molecules. Cytotoxic analogs of LHRH consist of a LHRH agonist, which is used as a carrier peptide and DOX or its derivatives. Cytotoxic analogs of LHRH, AEZS-108 (formerly known as AN-152) and AN-207, exhibit anti-cancer activity in various in vitro and in vivo models of LHRH-receptor positive cancers. In AEZS-108 (zoptarelin DOX) DOX is covalently linked to the LHRH agonist [D-Lys(6)]LHRH. Results of phase I and II clinical studies in patients with breast, endometrial and ovarian cancers demonstrated good anticancer activity with moderate toxic side effects and without any sign of cardiotoxicity so far. AEZS-108 is also being evaluated in phase I/II studies in castration resistant prostate cancer and metastatic bladder cancer. Because of the very promising phase II results in endometrial cancer, a multinational, multicenter phase III study of this malignancy has been initiated and is currently recruiting patients.

  18. The 5-HT7 receptor as a potential target for treating drug and alcohol abuse.

    Science.gov (United States)

    Hauser, Sheketha R; Hedlund, Peter B; Roberts, Amanda J; Sari, Youssef; Bell, Richard L; Engleman, Eric A

    2014-01-01

    Alcohol and drug abuse take a large toll on society and affected individuals. However, very few effective treatments are currently available to treat alcohol and drug addiction. Basic and clinical research has begun to provide some insights into the underlying neurobiological systems involved in the addiction process. Several neurotransmitter pathways have been implicated and distinct reward neurocircuitry have been proposed-including the mesocorticolimbic dopamine (MCL-DA) system and the extended amygdala. The serotonin (5-HT) neurotransmitter system is of particular interest and multiple 5-HT receptors are thought to play significant roles in alcohol and drug self-administration and the development of drug dependence. Among the 5-HT receptors, the 5-HT7 receptor is currently undergoing characterization as a potential target for the treatment of several psychiatric disorders. Although this receptor has received only limited research regarding addictive behaviors, aspects of its neuroanatomical, biochemical, physiological, pharmacological, and behavioral profiles suggest that it could play a key role in the addiction process. For instance, genomic studies in humans have suggested a link between variants in the gene encoding the 5-HT7 receptor and alcoholism. Recent behavioral testing using high-affinity antagonists in mice and preliminary tests with alcohol-preferring rats suggest that this receptor could mediate alcohol consumption and/or reinforcement and play a role in seeking/craving behavior. Interest in the development of new and more selective pharmacological agents for this receptor will aid in examining the 5-HT7 receptor as a novel target for treating addiction.

  19. The 5-HT-7 receptor as a potential target for treating drug and alcohol abuse

    Directory of Open Access Journals (Sweden)

    Sheketha R. Hauser

    2015-01-01

    Full Text Available Alcohol and drug abuse take a large toll on society and affected individuals. However, very few effective treatments are currently available to treat alcohol and drug addiction. Basic and clinical research has begun to provide some insights into the underlying neurobiological systems involved in the addiction process. Several neurotransmitter pathways have been implicated and distinct reward neurocircuitry have been proposed – including the mesocorticolimbic (MCL dopamine system and the extended amygdala. The serotonin (5-HT neurotransmitter system is of particular interest and multiple 5-HT receptors are thought to play significant roles in alcohol and drug self-administration and the development of drug dependence. Among the 5-HT receptors, the 5-HT-7 receptor is currently undergoing characterization as a potential target for the treatment of several psychiatric disorders. Although this receptor has received only limited research regarding addictive behaviors, aspects of its neuroanatomical, biochemical, physiological, pharmacological, and behavioral profiles suggest that it could play a key role in the addiction process. For instance, genomic studies in humans have suggested a link between variants in the gene encoding the 5-HT-7 receptor and alcoholism. Recent behavioral testing using high-affinity antagonists in mice and preliminary tests with alcohol-preferring rats suggest that this receptor could mediate alcohol consumption and/or reinforcement and play a role in seeking/craving behavior. Interest in the development of new and more selective pharmacological agents for this receptor will aid in examining the 5-HT-7 receptor as a novel target for treating addiction.

  20. A tail of two signals: the C terminus of the A(2A)-adenosine receptor recruits alternative signaling pathways.

    Science.gov (United States)

    Gsandtner, Ingrid; Freissmuth, Michael

    2006-08-01

    G protein-coupled receptors are endowed with carboxyl termini that vary greatly in length and sequence. In most instances, the distal portion of the C terminus is dispensable for G protein coupling. This is also true for the A(2A)-adenosine receptor, where the last 100 amino acids are of very modest relevance to G(s) coupling. The C terminus was originally viewed mainly as the docking site for regulatory proteins of the beta-arrestin family. These beta-arrestins bind to residues that have been phosphorylated by specialized kinases (G protein-coupled receptor kinases) and thereby initiate receptor desensitization and endocytosis. More recently, it has become clear that many additional "accessory" proteins bind to C termini of G protein-coupled receptors. The article by Sun et al. in the current issue of Molecular Pharmacology identifies translin-associated protein-X as yet another interaction partner of the A(2A) receptor; translin-associated protein allows the A(2A) receptor to impinge on the signaling mechanisms by which p53 regulates neuronal differentiation, but the underlying signaling pathways are uncharted territory. With a list of five known interaction partners, the C terminus of the A(2A) receptor becomes a crowded place. Hence, there must be rules that regulate the interaction. This allows the C terminus to act as coincidence detector and as signal integrator. Despite our ignorance about the precise mechanisms, the article has exciting implications: the gene encoding for translin-associated protein-X maps to a locus implicated in some forms of schizophrenia; A(2A) receptor agonists are candidate drugs for the treatment of schizophrenic symptoms. It is of obvious interest to explore a possible link.

  1. Targeting of peptide conjugated magnetic nanoparticles to urokinase plasminogen activator receptor (uPAR) expressing cells

    Science.gov (United States)

    Hansen, Line; Unmack Larsen, Esben Kjær; Nielsen, Erik Holm; Iversen, Frank; Liu, Zhuo; Thomsen, Karen; Pedersen, Michael; Skrydstrup, Troels; Nielsen, Niels Chr.; Ploug, Michael; Kjems, Jørgen

    2013-08-01

    Ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles are currently being used as a magnetic resonance imaging (MRI) contrast agent in vivo, mainly by their passive accumulation in tissues of interest. However, a higher specificity can ideally be achieved when the nanoparticles are targeted towards cell specific receptors and this may also facilitate specific drug delivery by an enhanced target-mediated endocytosis. We report efficient peptide-mediated targeting of magnetic nanoparticles to cells expressing the urokinase plasminogen activator receptor (uPAR), a surface biomarker for poor patient prognosis shared by several cancers including breast, colorectal, and gastric cancers. Conjugation of a uPAR specific targeting peptide onto polyethylene glycol (PEG) coated USPIO nanoparticles by click chemistry resulted in a five times higher uptake in vitro in a uPAR positive cell line compared to nanoparticles carrying a non-binding control peptide. In accordance with specific receptor-mediated recognition, a low uptake was observed in the presence of an excess of ATF, a natural ligand for uPAR. The uPAR specific magnetic nanoparticles can potentially provide a useful supplement for tumor patient management when combined with MRI and drug delivery.Ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles are currently being used as a magnetic resonance imaging (MRI) contrast agent in vivo, mainly by their passive accumulation in tissues of interest. However, a higher specificity can ideally be achieved when the nanoparticles are targeted towards cell specific receptors and this may also facilitate specific drug delivery by an enhanced target-mediated endocytosis. We report efficient peptide-mediated targeting of magnetic nanoparticles to cells expressing the urokinase plasminogen activator receptor (uPAR), a surface biomarker for poor patient prognosis shared by several cancers including breast, colorectal, and gastric cancers. Conjugation of a uPAR specific

  2. Continuous adenosine A2A receptor antagonism after focal cerebral ischemia in spontaneously hypertensive rats.

    Science.gov (United States)

    Fronz, Ulrike; Deten, Alexander; Baumann, Frank; Kranz, Alexander; Weidlich, Sarah; Härtig, Wolfgang; Nieber, Karen; Boltze, Johannes; Wagner, Daniel-Christoph

    2014-02-01

    Antagonism of the adenosine A2A receptor (A2AR) has been shown to elicit substantial neuroprotective properties when given immediately after cerebral ischemia. We asked whether the continuous application of a selective A2AR antagonist within a clinically relevant time window will be a feasible and effective approach to treat focal cerebral ischemia. To answer this question, we subjected 20 male spontaneously hypertensive rats to permanent middle cerebral artery occlusion and randomized them equally to a verum and a control group. Two hours after stroke onset, the animals received a subcutaneous implantation of an osmotic minipump filled with 5 mg kg(-1) day(-1) 8-(3-chlorostyryl) caffeine (CSC) or vehicle solution. The serum level of CSC was measured twice a day for three consecutive days. The infarct volume was determined at days 1 and 3 using magnetic resonance imaging. We found the serum level of CSC showing a bell-shaped curve with its maximum at 36 h. The infarct volume was not affected by continuous CSC treatment. These results suggest that delayed and continuous CSC application was not sufficient to treat acute ischemic stroke, potentially due to unfavorable hepatic elimination and metabolization of the pharmaceutical.

  3. Expression of phospholipase A2 receptor in primary cultured podocytes derived from dog kidneys.

    Science.gov (United States)

    Sugahara, Go; Kamiie, Junichi; Kobayashi, Ryosuke; Mineshige, Takayuki; Shirota, Kinji

    2016-06-01

    Phospholipase A2 receptor (PLA2R) expressed in human podocytes has been highlighted as a causative autoantigen of human idiopathic membranous nephropathy. However, its expression was found to be minimal or absent in murine and rat podocytes. In this study, immunofluorescence revealed the expression of PLA2R in the glomerular podocytes in the kidney tissue sections of dogs. We then attempted to culture canine podocytes and investigate the expression of PLA2R in these cells. Glomeruli were isolated from dog kidneys and cultured to obtain podocytes using nylon mesh-based isolation method as followed for isolating rat podocytes. The cultured cells expressed PLA2R mRNA and protein in addition to other podocyte markers (synaptopodin, podocin and nephrin). These results indicate that the canine podocytes express PLA2R.

  4. Antibodies to m-type phospholipase A2 receptor in children with idiopathic membranous nephropathy.

    Science.gov (United States)

    Kumar, Vinod; Ramachandran, Raja; Kumar, Ashwani; Nada, Ritambhra; Suri, Deepti; Gupta, Anju; Kohli, Harbir Singh; Gupta, Krishan Lal; Jha, Vivekanand

    2015-08-01

    Idiopathic membranous nephropathy (IMN), the commonest cause of adult nephrotic syndrome (NS), accounts for only a minority of paediatric NS. Antibodies to m-type phospholipase A2 receptor (PLA2R) are seen in two-thirds of adult IMN cases. PLA2R staining in glomerular deposits is observed in 74% and 45% of adult and paediatric IMN cases, respectively. However, there are no reports of anti-PLA2R in paediatric IMN. We evaluated anti-PLA2R levels and PLA2R in gloemrular deposits in paediatric IMN seen at our center. Five cases were enrolled, all the cases stained for PLA2R in glomeruli and three (60%) had antibodies to PLA2R antigen. There was a parellel reduction in proteinuria and anti-PLA2R titer. The present report suggests that PLA2R has a contributory role in the pathogenesis of paediatric IMN.

  5. Phospholipase A2 Receptor-Positive Idiopathic Membranous Glomerulonephritis with Onset at 95 Years: Case Report

    Science.gov (United States)

    Kubota, Keiichi; Hoshino, Junichi; Ueno, Toshiharu; Mise, Koki; Hazue, Ryo; Sekine, Akinari; Yabuuchi, Junko; Yamanouchi, Masayuki; Suwabe, Tatsuya; Kikuchi, Koichi; Sumida, Keiichi; Hayami, Noriko; Sawa, Naoki; Takaichi, Kenmei; Fujii, Takeshi; Ohashi, Kenichi; Akiyama, Shinichi; Maruyama, Shoichi; Ubara, Yoshifumi

    2016-01-01

    A 95-year-old woman was admitted to our hospital for evaluation of bilateral lower-limb edema persisting for 3 months. Serum creatinine was 1.55 mg/dl, and urinary protein excretion was 9.1 g/day. Renal biopsy revealed stage 1 membranous glomerulonephritis (MGN) with immunoglobulin G4-dominant staining. This patient did not have any underlying disease such as infection with hepatitis B or C virus or malignancy, and anti-phospholipase A2 receptor (PLA2R) antibody was detected in the serum. Accordingly, idiopathic MGN was diagnosed. Corticosteroid therapy was avoided, but hemodialysis was required to treat generalized edema. The patient is currently doing well. This is the oldest reported case of idiopathic MGN with positivity for anti-PLA2R antibody. PMID:27390744

  6. GABAB receptor trafficking and interacting proteins: targets for the development of highly specific therapeutic strategies to treat neurological disorders?

    Science.gov (United States)

    Benke, Dietmar

    2013-12-01

    GABAB receptors mediate slow inhibitory neurotransmission throughout the central nervous system thereby controlling the excitability of neurons. They have been implicated in numerous neurological disorders making them an attractive drug target. However, due to considerable side effects, the agonist baclofen is so far the only drug on the market targeting GABAB receptors, primarily for the treatment of spasticity. Because GABAB receptors are involved in a variety of brain functions it is rather unlikely to avoid unwanted effects with systemically administered drugs directly addressing ligand binding sites of the receptor. To minimize side effects, it would be desirable to target only those receptors involved in a given pathological state. This commentary discusses the idea that restoring impaired GABAB receptor function in diseased neurons by interfering with receptor-protein interactions may be an approach to specifically target only those receptors involved in the pathological state. Two recently discovered mechanisms that down-regulate the level of functional GABAB receptors most likely contribute to cerebral ischemia and neuropathic pain, respectively. In both mechanisms, small interfering peptides disrupting protein-protein interactions may offer a highly specific means to restore normal receptor function selectively at the site of malfunction. If restored functional GABAB receptor expression in these diseases has beneficial effects, this may serve as a starting point for the development of a highly specific therapeutic interventions. Such an approach is expected to minimize side effects because it promises to leave those GABAB receptors unaffected which are not involved in the dysfunction.

  7. Steroid hormone receptors and prostate cancer: role of structural dynamics in therapeutic targeting

    Science.gov (United States)

    Kumar, Raj

    2016-01-01

    Steroid hormone receptors (SHRs) act in cell type- and gene-specific manner through interactions with coregulatory proteins to regulate numerous physiological and pathological processes at the level of gene regulation. Binding of steroid receptor modulator (SRM) ligand leads to allosteric changes in SHR to exert positive or negative effects on the expression of target genes. Due, in part, to the fact that current SRMs generally target ligand binding domain (LBD)/AF2 and neglect intrinsically disordered (ID) N-terminal domain (NTD)/AF1, clinically relevant SRMs lack selectivity and are also prone to the development of resistance over time. Therefore, to maximize the efficacy of SHR-based therapeutics, the possibility of developing unique modulators that act to control AF1 activity must be considered. Recent studies targeting androgen receptor's (AR's) ID AF1 domain for the castration-resistant prostate cancer has provided the possibility of therapeutically targeting ID NTD/AF1 surfaces by allosteric modulations to achieve desired effects. In this review article, we discuss how inter- and intra- molecular allosteric regulations controlled by AR's structural flexibility and dynamics particularly the ID NTD/AF1 is an emerging area of investigation, which could be exploited for drug development and therapeutic targeting of prostate cancer. PMID:27364545

  8. De novo analysis of receptor binding affinity data of 8-ethenyl-xanthine antagonists to adenosine A1 and A2a receptors.

    Science.gov (United States)

    Dalpiaz, A; Gessi, S; Varani, K; Borea, P A

    1997-05-01

    The receptor binding affinity data to adenosine A1 and A2a receptors of a wide series of 8-ethenyl-xanthine derivatives has been analyzed by means of the Free-Wilson model. The analysis of the individual group contributions (aij) shows the importance of the presence of an ethenyl moiety at position 8 on the xanthine ring for obtaining selective A2a antagonists. The different aij values of the substituents for the adenosine. A1 receptor do not correlate with the corresponding ones for the A2a receptor, indicating the possibility to obtain A1 and A2a selective compounds. The presence of aromatic substituents at the 8-ethenyl group, such as 3,5-(OCH3)2-phenyl, permits to obtain strongly A2a selective compounds (affinity ratio of up to 100); moreover, it appears that 8-ethenyl-xanthinic derivatives cannot have high selectivity for the adenosine A1 receptor (affinity ratio < or = 10).

  9. Expression of growth factor receptors and targeting of EGFR in cholangiocarcinoma cell lines

    Directory of Open Access Journals (Sweden)

    Kellermeier Silvia

    2010-06-01

    Full Text Available Abstract Background Cholangiocarcinoma (CC is a malignant neoplasm of the bile ducts or the gallbladder. Targeting of growth factor receptors showed therapeutic potential in palliative settings for many solid tumors. The aim of this study was to determine the expression of seven growth factor receptors in CC cell lines and to assess the effect of blocking the EGFR receptor in vitro. Methods Expression of EGFR (epithelial growth factor receptor, HGFR (hepatocyte growth factor receptor IGF1R (insulin-like growth factor 1 receptor, IGF2R (insulin-like growth factor 2 receptor and VEGFR1-3 (vascular endothelial growth factor receptor 1-3 were examined in four human CC cell lines (EGI-1, HuH28, OZ and TFK-1. The effect of the anti-EGFR-antibody cetuximab on cell growth and apoptosis was studied and cell lines were examined for KRAS mutations. Results EGFR, HGFR and IGFR1 were present in all four cell lines tested. IGFR2 expression was confirmed in EGI-1 and TFK-1. No growth-inhibitory effect was found in EGI-1 cells after incubation with cetuximab. Cetuximab dose-dependently inhibited growth in TFK-1. Increased apoptosis was only seen in TFK-1 cells at the highest cetuximab dose tested (1 mg/ml, with no dose-response-relationship at lower concentrations. In EGI-1 a heterozygous KRAS mutation was found in codon 12 (c.35G>A; p.G12D. HuH28, OZ and TFK-1 lacked KRAS mutation. Conclusion CC cell lines express a pattern of different growth receptors in vitro. Growth factor inhibitor treatment could be affected from the KRAS genotype in CC. The expression of EGFR itself does not allow prognoses on growth inhibition by cetuximab.

  10. P2X receptors as targets for the treatment of status epilepticus

    Directory of Open Access Journals (Sweden)

    David C Henshall

    2013-11-01

    Full Text Available Prolonged seizures are amongst the most common neurological emergencies. Status epilepticus is a state of continuous seizures that is life-threatening and prompt termination of status epilepticus is critical to protect the brain from permanent damage. Frontline treatment comprises parenteral administration of anticonvulsants such as lorazepam that facilitate γ-amino butyric acid (GABA transmission. Because status epilepticus can become refractory to anticonvulsants in a significant proportion of patients, drugs which act on different neurotransmitter systems may represent potential adjunctive treatments. P2X receptors are a class of ligand-gated ion channel activated by ATP that contributes to neuro- and glio-transmission. P2X receptors are expressed by both neurons and glia in various brain regions, including the hippocampus. Electrophysiology, pharmacology and genetic studies suggest certain P2X receptors are activated during pathologic brain activity. Expression of several members of the family including P2X2, P2X4 and P2X7 receptors has been reported to be altered in the hippocampus following status epilepticus. Recent studies have shown that ligands of the P2X7 receptor can have potent effects on seizure severity during status epilepticus and mice lacking this receptor display altered seizures in response to chemoconvulsants. Antagonists of the P2X7 receptor also modulate neuronal death, microglial responses and neuroinflammatory signaling. Recent work also found altered neuronal injury and inflammation after status epilepticus in mice lacking the P2X4 receptor. In summary, members of the P2X receptor family may serve important roles in the pathophysiology of status epilepticus and represent novel targets for seizure control and neuroprotection.

  11. Bile Acid Nuclear Receptor Farnesoid X Receptor: Therapeutic Target for Nonalcoholic Fatty Liver Disease

    Science.gov (United States)

    Kim, Sun-Gi; Kim, Byung-Kwon; Kim, Kyumin

    2016-01-01

    Nonalcoholic fatty liver disease (NAFLD) is one of the causes of fatty liver, occurring when fat is accumulated in the liver without alcohol consumption. NAFLD is the most common liver disorder in advanced countries. NAFLD is a spectrum of pathology involving hepatic steatosis with/without inflammation and nonalcoholic steatohepatitis with accumulation of hepatocyte damage and hepatic fibrosis. Recent studies have revealed that NAFLD results in the progression of cryptogenic cirrhosis that leads to hepatocarcinoma and cardiovascular diseases such as heart failure. The main causes of NAFLD have not been revealed yet, metabolic syndromes including obesity and insulin resistance are widely accepted for the critical risk factors for the pathogenesis of NAFLD. Nuclear receptors (NRs) are transcriptional factors that sense environmental or hormonal signals and regulate expression of genes, involved in cellular growth, development, and metabolism. Several NRs have been reported to regulate genes involved in energy and xenobiotic metabolism and inflammation. Among various NRs, farnesoid X receptor (FXR) is abundantly expressed in the liver and a key regulator to control various metabolic processes in the liver. Recent studies have shown that NAFLD is associated with inappropriate function of FXR. The impact of FXR transcriptional activity in NAFLD is likely to be potential therapeutic strategy, but still requires to elucidate underlying potent therapeutic mechanisms of FXR for the treatment of NAFLD. This article will focus the physiological roles of FXR and establish the correlation between FXR transcriptional activity and the pathogenesis of NAFLD. PMID:28029021

  12. Bile Acid Nuclear Receptor Farnesoid X Receptor: Therapeutic Target for Nonalcoholic Fatty Liver Disease

    Directory of Open Access Journals (Sweden)

    Sun-Gi Kim

    2016-12-01

    Full Text Available Nonalcoholic fatty liver disease (NAFLD is one of the causes of fatty liver, occurring when fat is accumulated in the liver without alcohol consumption. NAFLD is the most common liver disorder in advanced countries. NAFLD is a spectrum of pathology involving hepatic steatosis with/without inflammation and nonalcoholic steatohepatitis with accumulation of hepatocyte damage and hepatic fibrosis. Recent studies have revealed that NAFLD results in the progression of cryptogenic cirrhosis that leads to hepatocarcinoma and cardiovascular diseases such as heart failure. The main causes of NAFLD have not been revealed yet, metabolic syndromes including obesity and insulin resistance are widely accepted for the critical risk factors for the pathogenesis of NAFLD. Nuclear receptors (NRs are transcriptional factors that sense environmental or hormonal signals and regulate expression of genes, involved in cellular growth, development, and metabolism. Several NRs have been reported to regulate genes involved in energy and xenobiotic metabolism and inflammation. Among various NRs, farnesoid X receptor (FXR is abundantly expressed in the liver and a key regulator to control various metabolic processes in the liver. Recent studies have shown that NAFLD is associated with inappropriate function of FXR. The impact of FXR transcriptional activity in NAFLD is likely to be potential therapeutic strategy, but still requires to elucidate underlying potent therapeutic mechanisms of FXR for the treatment of NAFLD. This article will focus the physiological roles of FXR and establish the correlation between FXR transcriptional activity and the pathogenesis of NAFLD.

  13. Gold Nanorods Targeted to Delta Opioid Receptor: Plasmon-Resonant Contrast and Photothermal Agents

    Directory of Open Access Journals (Sweden)

    Kvar C. Black

    2008-01-01

    Full Text Available Molecularly targeted gold nanorods were investigated for applications in both diagnostic imaging and disease treatment with cellular resolution. The nanorods were tested in two genetically engineered cell lines derived from the human colon carcinoma HCT-116, a model for studying ligand-receptor interactions. One of these lines was modified to express delta opioid receptor (δOR and green fluorescent protein, whereas the other was receptor free and expressed a red fluorescent protein, to serve as the control. Deltorphin, a high-affinity ligand for δOR, was stably attached to the gold nanorods through a thiol-terminated linker. In a mixed population of cells, we demonstrated selective imaging and destruction of receptor-expressing cells while sparing those cells that did not express the receptor. The molecularly targeted nanorods can be used as an in vitro ligand-binding and cytotoxic treatment assay platform and could potentially be applied in vivo for diagnostic and therapeutic purposes with endoscopic technology.

  14. Emerging peripheral receptor targets for deep-tissue craniofacial pain therapies.

    Science.gov (United States)

    Ambalavanar, R; Dessem, D

    2009-03-01

    While effective therapies are available for some types of craniofacial pain, treatments for deep-tissue craniofacial pain such as temporomandibular disorders are less efficacious. Several ion channels and receptors which are prominent in craniofacial nociceptive mechanisms have been identified on trigeminal primary afferent neurons. Many of these receptors and channels exhibit unusual distributions compared with extracranial regions. For example, expression of the ATP receptor P2X(3) is strongly implicated in nociception and is more abundant on trigeminal primary afferent neurons than analogous extracranial neurons, making them potentially productive targets specifically for craniofacial pain therapies. The initial part of this review therefore focuses on P2X(3) as a potential therapeutic target to treat deep-tissue craniofacial pain. In the trigeminal ganglion, P2X(3) receptors are often co-expressed with the nociceptive neuropeptides CGRP and SP. Therefore, we discuss the role of CGRP and SP in deep-tissue craniofacial pain and suggest that neuropeptide antagonists, which have shown promise for the treatment of migraine, may have wider therapeutic potential, including the treatment of deep-tissue craniofacial pain. P2X(3), TRPV1, and ASIC3 are often co-expressed in trigeminal neurons, implying the formation of functional complexes that allow craniofacial nociceptive neurons to respond synergistically to altered ATP and pH in pain. Future therapeutics for craniofacial pain thus might be more efficacious if targeted at combinations of P2X(3), CGRP, TRPV1, and ASIC3.

  15. Dopamine D3 receptors as a therapeutic target for methamphetamine dependence.

    Science.gov (United States)

    Paterson, Neil E; Vocci, Frank; Sevak, Rajkumar J; Wagreich, Eric; London, Edythe D

    2014-01-01

    Methamphetamine (MA) use disorders are major public health problems nationally and worldwide and treatment remains an unmet need. (1) To review preclinical and clinical studies identifying the dopamine D3 receptor as a therapeutic target for substance use disorders (SUDs), including MA dependence, (2) to consider buspirone (Buspar®) as a potential medication based on its dopamine D3 receptor antagonist properties, and (3) to evaluate the safety and initial efficacy of buspirone in a pilot study of MA-dependent individuals. Literature on the dopamine D3 receptor as a therapeutic target and on the potential of buspirone as a novel therapy for MA dependence was reviewed. The cardiovascular and subjective effects of intravenous MA challenge were assessed in five non-treatment seeking individuals. Participants met DSM-IV criteria for MA dependence and were treated subacutely (9 days) with buspirone (60 mg daily). The literature identified the dopamine D3 receptor as a therapeutic target for MA dependence, a safe and approved medication, and a valuable opportunity to re-purpose buspirone for treating MA dependence and perhaps other SUDs. Pilot data (n = 5) indicated that buspirone is safe in MA-using individuals and comparison against historical placebo data from this laboratory suggested that at least some aspects of the subjective properties of MA may be diminished during buspirone treatment. Future studies should include a small-scale, placebo-controlled Phase IIa trial of buspirone in MA dependence.

  16. TRA-418, a novel compound having both thromboxane A(2) receptor antagonistic and prostaglandin I(2) receptor agonistic activities: its antiplatelet effects in human and animal platelets.

    Science.gov (United States)

    Yamada, N; Miyamoto, M; Isogaya, M; Suzuki, M; Ikezawa, S; Ohno, M; Otake, A; Umemura, K

    2003-08-01

    TRA-418 is a novel compound that has been found in our screening for compounds having both thromboxane A2 (TP) receptor antagonistic and prostaglandin I2 (IP) receptor agonistic activities. In the binding assays, TRA-418 showed a 10-fold higher affinity to TP-receptors than IP-receptors. TRA-418 inhibited platelet aggregation induced by the TP-receptor agonist, U-46619 and by arachidonic acid at concentrations lower than those required for inhibition of ADP-induced aggregations. Furthermore, TRA-418 inhibited not only platelet aggregation induced by ADP alone, but also that induced by ADP in the presence of the TP-receptor antagonist, SQ-29548. When the IC50 values of TRA-418 for platelet aggregation were estimated in platelet preparations from monkeys, dogs, cats, and rats using ADP and arachidonic acid as the platelet stimulating agents, it was found that the values estimated in monkey platelets were quite similar to those estimated in human platelets. In ex vivo platelet aggregation in monkeys, TRA-418 exhibited significant inhibitory effects on arachidonic acid-induced aggregation in platelet preparations from monkeys treated at 3 micro g kg min-1 or higher doses, where neither a significant decrease in blood pressure nor a significant increase in heart rate was observed. These results are consistent with the fact that TRA-418 has a relatively potent TP-receptor antagonistic activity together with a relatively weak IP-receptor agonistic activity.

  17. Enhanced expression of the M-type phospholipase A2 receptor in glomeruli correlates with serum receptor antibodies in primary membranous nephropathy.

    Science.gov (United States)

    Hoxha, Elion; Kneißler, Ursula; Stege, Gesa; Zahner, Gunther; Thiele, Ina; Panzer, Ulf; Harendza, Sigrid; Helmchen, Udo M; Stahl, Rolf A K

    2012-10-01

    The M-type phospholipase A2 receptor (PLA2R) is the major target antigen in idiopathic membranous nephropathy with detectable autoantibodies in the serum of up to 70% of patients. In retrospective studies, the PLA2R-autoantibody titer in the serum was sometimes negative indicating their measurement alone may be inconclusive. In order to better differentiate between primary and secondary membranous nephropathy, we conducted a prospective study that included 88 patients with a histologic diagnosis of membranous nephropathy. Immunohistochemical analysis for PLA2R was faintly positive in kidneys from normal individuals and patients with various other glomerular injuries. In 61 of the 88 patients, PLA2R expression was strongly positive in glomeruli, and in 60 of these patients PLA2R autoantibodies were also detected in the serum. The 27 patients negative for serum PLA2R autoantibodies were faintly positive for PLA2R staining in glomeruli and in 15 of these patients a secondary cause was found. The remaining 12 patients have a yet undetected secondary cause of membranous nephropathy or have different glomerular antigens other than PLA2R. Thus, increased staining for PLA2R in glomeruli of renal biopsies tightly correlates with the presence of PLA2R autoantibodies in the serum and this may help discriminate between primary and secondary membranous nephropathy.

  18. Toll-like receptors are potential therapeutic targets in rheumatoid arthritis

    Institute of Scientific and Technical Information of China (English)

    Siamak; Sandoghchian; Shotorbani

    2011-01-01

    Toll-like receptors (TLRs) are found on the membranes of pattern recognition receptors and not only play important roles in activating immune responses but are also involved in the pathogenesis of inflammatory disease, injury and cancer. Furthermore, TLRs are also able to recognize endogenous alarmins released by damaged tissue and necrosis and/or apoptotic cells and are present in numerous autoimmune diseases. Therefore, the release of endogenous TLR ligands plays an important role in initiating and driving inflammatory diseases. Increasing data suggest a role for TLR signaling in rheumatoid arthritis, which is an autoimmune disease. Although their involvement is not comprehensively understood, the TLRs signaling transducers may provide potential therapeutic targets.

  19. Macrophage galactose-type C-type lectin receptor for DC targeting of antitumor glycopeptide vaccines

    DEFF Research Database (Denmark)

    Nuti, M; Zizzari, I; Napoletano, C;

    2011-01-01

    e13528 Background: Dendritic cells (DCs) are the most potent antigen presenting cells and are employed in cancer vaccination. Several receptors are being studied in order to identif strategies to increase DCs activating capacity. The C-type lectin macrophage galactose type C-type lectin (MGL...... of IFNg and IL-2 secretion by both CD8 and CD4 T cells. CONCLUSIONS: These results demonstrate that MGL engagement profoundly affects DC plasticity inducing and directing a Th1 immune response. Moreover, MGL receptor expressed on human DC can be targeted by glycopeptide based vaccines with adjuvant...

  20. Role of receptor tyrosine kinases in gastric cancer: New targets for a selective therapy

    Institute of Scientific and Technical Information of China (English)

    JC Becker; C Müller-Tidow; H Serve; W Domschke; T Pohle

    2006-01-01

    Receptor tyrosine kinases (RTKs) such as the epidermal growth factor receptor family participate in several steps of tumor formation including proliferation and metastatic spread. Several known RTKs are upregulated in gastric cancer being prime targets of a tailored therapy. Only preliminary data exist, however, on the use of the currently clinically available drugs such as trastuzumab,cetuximab, bevacizumab, gefitinib, erlotinib, and imatinib in the setting of gastric cancer. Preclinical data suggest a potential benefit of their use, especially in combination with "conventional" cytostatic therapy. This review summarizes the current knowledge about their use in cancer therapy as well as new approaches and drugs to optimize treatment success.

  1. TP receptor as a therapeutic target in atherosclerosis and related cardiovascular diseases.

    Science.gov (United States)

    Ishizuka, Toshiaki; Higashino, Hideaki

    2006-11-01

    It had already showed that several thromboxane A(2) receptor (TP receptor) antagonists might be utilized in the treatment of cardiovascular diseases. In addition, recent reports suggested that TP receptor antagonism may be able to restrict vascular inflammation in atherosclerotic vessels. In particular, S18886 has been developed as a non-prostanoid TP receptor antagonist derived from sulotroban that is characterized by a tetrahydronaphthalene ring as a spacer between the 4-cholophenylsulfonamide group and carboxylic acid. Several reports using experimental animal models of atherosclerosis indicated that S18886 caused a regression of advanced atherosclerosis. More recently, several studies and patents showed that new thromboxane modulators combined with another pharmacological activities have been developed. Ohtake et al. discovered TRA-418 (a benzene-condensed heterocyclic derivative) having a TP receptor antagonistic activity and a prostaglandin I(2) receptor agonistic activity. Cesagrande found that 4-methyl-N- (4-trans-nitrooxycyclohexyl)-N-(3-pyridinylmethyl)-1,3- benzenedicarboxamide is endowed with anti-thromboxane and NO-donor actions. Oketani et al. discovered that E3040, a novel benzothiazole derivative, inhibited TXA(2) synthase and 5-LO activities. EK112, a combined angiotensin II and TP receptor antagonist, was developed. These new compounds may be able to restrict further infiltration of inflammatory cells in atherosclerotic vessels, thus stabilizing vulnerable plaques in the related cardiovascular diseases.

  2. Receptors and ionic transporters in nuclear membranes: new targets for therapeutical pharmacological interventions.

    Science.gov (United States)

    Bkaily, Ghassan; Avedanian, Levon; Al-Khoury, Johny; Ahmarani, Lena; Perreault, Claudine; Jacques, Danielle

    2012-08-01

    Work from our group and other laboratories showed that the nucleus could be considered as a cell within a cell. This is based on growing evidence of the presence and role of nuclear membrane G-protein coupled receptors and ionic transporters in the nuclear membranes of many cell types, including vascular endothelial cells, endocardial endothelial cells, vascular smooth muscle cells, cardiomyocytes, and hepatocytes. The nuclear membrane receptors were found to modulate the functioning of ionic transporters at the nuclear level, and thus contribute to regulation of nuclear ionic homeostasis. Nuclear membranes of the mentioned types of cells possess the same ionic transporters; however, the type of receptors is cell-type dependent. Regulation of cytosolic and nuclear ionic homeostasis was found to be dependent upon a tight crosstalk between receptors and ionic transporters of the plasma membranes and those of the nuclear membrane. This crosstalk seems to be the basis for excitation-contraction coupling, excitation-secretion coupling, and excitation - gene expression coupling. Further advancement in this field will certainly shed light on the role of nuclear membrane receptors and transporters in health and disease. This will in turn enable the successful design of a new class of drugs that specifically target such highly vital nuclear receptors and ionic transporters.

  3. Secretory phospholipase A2-mediated neuronal cell death involves glutamate ionotropic receptors

    DEFF Research Database (Denmark)

    de Turco, Elena B; Diemer, Nils Henrik; Bazan, Nicolas G

    2002-01-01

    To define the significance of glutamate ionotropic receptors in sPLA -mediated neuronal cell death we used the NMDA receptor antagonist MK-801 and the AMPA receptor antagonist PNQX. In primary neuronal cell cultures both MK-801 and PNQX inhibited sPLA - and glutamate-induced neuronal death. [ H]A...

  4. Molecular photoacoustic tomography of breast cancer using receptor targeted magnetic iron oxide nanoparticles as contrast agents.

    Science.gov (United States)

    Xi, Lei; Grobmyer, Stephen R; Zhou, Guangyin; Qian, Weiping; Yang, Lily; Jiang, Huabei

    2014-06-01

    In this report, we present a breast imaging technique combining high-resolution near-infrared (NIR) light induced photoacoustic tomography (PAT) with NIR dye-labeled amino-terminal fragments of urokinase plasminogen activator receptor (uPAR) targeted magnetic iron oxide nanoparticles (NIR830-ATF-IONP) for breast cancer imaging using an orthotopic mouse mammary tumor model. We show that accumulation of the targeted nanoparticles in the tumor led to photoacoustic contrast enhancement due to the high absorption of iron oxide nanoparticles (IONP). NIR fluorescence images were used to validate specific delivery of NIR830-ATF-IONP to mouse mammary tumors. We found that systemic delivery of the targeted IONP produced 4- and 10-fold enhancement in photoacoustic signals in the tumor, compared to the tumor of the mice that received non-targeted IONP or control mice. The use of targeted nanoparticles allowed imaging of tumors located as deep as 3.1 cm beneath the normal tissues. Our study indicates the potential of the combination of photoacoustic tomography and receptor-targeted NIR830-ATF-IONP as a clinical tool that can provide improved specificity and sensitivity for breast cancer detection.

  5. Thrombin-Mediated Direct Activation of Proteinase-Activated Receptor-2: Another Target for Thrombin Signaling.

    Science.gov (United States)

    Mihara, Koichiro; Ramachandran, Rithwik; Saifeddine, Mahmoud; Hansen, Kristina K; Renaux, Bernard; Polley, Danny; Gibson, Stacy; Vanderboor, Christina; Hollenberg, Morley D

    2016-05-01

    Thrombin is known to signal to cells by cleaving/activating a G-protein-coupled family of proteinase-activated receptors (PARs). The signaling mechanism involves the proteolytic unmasking of an N-terminal receptor sequence that acts as a tethered receptor-activating ligand. To date, the recognized targets of thrombin cleavage and activation for signaling are PAR1 and PAR4, in which thrombin cleaves at a conserved target arginine to reveal a tethered ligand. PAR2, which like PAR1 is also cleaved at an N-terminal arginine to unmask its tethered ligand, is generally regarded as a target for trypsin but not for thrombin signaling. We now show that thrombin, at concentrations that can be achieved at sites of acute injury or in a tumor microenvironment, can directly activate PAR2 vasorelaxation and signaling, stimulating calcium and mitogen-activated protein kinase responses along with triggeringβ-arrestin recruitment. Thus, PAR2 can be added alongside PAR1 and PAR4 to the targets, whereby thrombin can affect tissue function.

  6. Radiotracer Methods for Targeted Imaging of the Epidermal Growth Factor Receptor

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Kyung Ho; Lee, Kyung Han [Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of)

    2008-06-15

    While indirect targeting strategies using reporter-genes are taking center stage in current molecular imaging research, another vital strategy has long involved direct imaging of specific receptors using radiolabeled ligands. Recently, there is renewal of immense interest in this area with particular attention to the epidermal growth factor receptor (EGFR), a transmembrane glycoprotein critically involved in the regulation of many cellular functions and malignancies. Recently, two novel classes of EGFR-targeting anticancer drugs have entered clinical trials with great expectations. These are monoclonal antibodies such as cetuximab that target the extracellular domain, and small molecule tyrosine kinase inhibitors such as gefitinib (Iressa) and erlotinib (Tarceva) that target the catalytic domain of the receptor. However, early results have showed disappointing survival benefits, disclosing a major challenge for this therapeutic strategy; namely, the need to identify tumors that are most likely to respond to the agents. To address this important clinical issue, several noninvasive imaging techniques are under investigation including radiolabeled probes based on small molecule tyrosine kinase inhibitors, anti-EGFR antibodies, and EGF peptides. This review describes the current status, limitations, and future prospects in the development of radiotracer methods for EGFR imaging.

  7. The association of thromboxane A2 receptor with lipid rafts is a determinant for platelet functional responses.

    Science.gov (United States)

    Moscardó, A; Vallés, J; Latorre, A; Santos, M T

    2014-08-25

    We have investigated the presence of thromboxane A2 (TXA2) receptor associated with lipid rafts in human platelets and the regulation of platelet function in response to TXA2 receptor agonists when lipid rafts are disrupted by cholesterol extraction. Platelet aggregation with TXA2 analogs U46619 and IBOP was almost blunted in cholesterol-depleted platelets, as well as αIIbβ3 integrin activation and P-selectin exposure. Raft disruption also inhibited TXA2-induced cytosolic calcium increase and nucleotide release, ruling out an implication of P2Y12 receptor. An important proportion of TXA2 receptor (40%) was colocalized at lipid rafts. The presence of the TXA2 receptor associated with lipid rafts in platelets is important for functional platelet responses to TXA2.

  8. Pharmacologic antagonism of thromboxane A2 receptors by trimetoquinol analogs in vitro and in vivo

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Y.; Romstedt, K.J.; Doyle, K.; Harrold, M.W.; Gerhardt, M.A.; Miller, D.D.; Patil, P.N.; Feller, D.R. (Ohio State University, Columbus (USA))

    1991-01-01

    Although (-)-(S)-trimetoquinol (1-(3,4,5-trimethoxy-benzyl)- 6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline; TMQ) is recognized as a potent bronchodilator, (+)-(R)-TMQ is a selective antagonist of human platelet aggregation and serotonin secretion induced by thromboxane A2 (TXA2) agonists. To confirm the pharmacological actions of TMQ analogs, the interaction of the drugs with TXA2 receptors was examined in human platelets and in a mouse sudden death model. The inhibitory potencies of TMQ analogs (pIC50 values) for displacement of (3H)SQ 29,548 binding to platelets showed excellent correlation with the respective pIC50 (-log IC50) values for U46619-induced aggregation (r = 0.99, P less than 0.01) and serotonin secretion (r = 0.99, P less than 0.01) in human platelet-rich plasma and for whole blood aggregation (r = 0.99, P less than 0.01). In each system, the rank order of inhibitory potencies was rac-iodoTMQ greater than or equal to (+)-(R)-TMQ greater than rac-TMQ much greater than (-)-(S)-TMQ. Antithrombotic effects of TMQ analogs were evaluated in a mouse sudden death model. In vivo antithrombotic potencies of these compounds were consistent with the in vitro potencies as TXA2 receptor antagonists in platelet systems. Administration of rac-iodoTMQ, (+)-(R)-TMQ and rac-TMQ 15 min before the injection of U46619 (800 micrograms/kg, iv) protected mice against U46619-induced sudden death. On the other hand, (-)-(S)-TMQ did not protect animals against death. Protection of U46619-induced cardiopulmonary thrombosis by TMQ analogs was seen at doses of 3-100 mg/kg.

  9. Creatine, similarly to ketamine, affords antidepressant-like effects in the tail suspension test via adenosine A₁ and A2A receptor activation.

    Science.gov (United States)

    Cunha, Mauricio P; Pazini, Francis L; Rosa, Julia M; Ramos-Hryb, Ana B; Oliveira, Ágatha; Kaster, Manuella P; Rodrigues, Ana Lúcia S

    2015-06-01

    The benefits of creatine supplementation have been reported in a broad range of central nervous systems diseases, including depression. A previous study from our group demonstrated that creatine produces an antidepressant-like effect in the tail suspension test (TST), a predictive model of antidepressant activity. Since depression is associated with a dysfunction of the adenosinergic system, we investigated the involvement of adenosine A1 and A2A receptors in the antidepressant-like effect of creatine in the TST. The anti-immobility effect of creatine (1 mg/kg, po) or ketamine (a fast-acting antidepressant, 1 mg/kg, ip) in the TST was prevented by pretreatment of mice with caffeine (3 mg/kg, ip, nonselective adenosine receptor antagonist), 8-cyclopentyl-1,3-dipropylxanthine (DPCPX) (2 mg/kg, ip, selective adenosine A1 receptor antagonist), and 4-(2-[7-amino-2-{2-furyl}{1,2,4}triazolo-{2,3-a}{1,3,5}triazin-5-yl-amino]ethyl)-phenol (ZM241385) (1 mg/kg, ip, selective adenosine A2A receptor antagonist). In addition, the combined administration of subeffective doses of creatine and adenosine (0.1 mg/kg, ip, nonselective adenosine receptor agonist) or inosine (0.1 mg/kg, ip, nucleoside formed by the breakdown of adenosine) reduced immobility time in the TST. Moreover, the administration of subeffective doses of creatine or ketamine combined with N-6-cyclohexyladenosine (CHA) (0.05 mg/kg, ip, selective adenosine A1 receptor agonist), N-6-[2-(3,5-dimethoxyphenyl)-2-(methylphenyl)ethyl]adenosine (DPMA) (0.1 mg/kg, ip, selective adenosine A2A receptor agonist), or dipyridamole (0.1 μg/mouse, icv, adenosine transporter inhibitor) produced a synergistic antidepressant-like effect in the TST. These results indicate that creatine, similarly to ketamine, exhibits antidepressant-like effect in the TST probably mediated by the activation of both adenosine A1 and A2A receptors, further reinforcing the potential of targeting the purinergic system to the management of mood disorders.

  10. EGFR and EphA2 are host factors for hepatitis C virus entry and possible targets for antiviral therapy

    Science.gov (United States)

    Lupberger, Joachim; Zeisel, Mirjam B.; Xiao, Fei; Thumann, Christine; Fofana, Isabel; Zona, Laetitia; Davis, Christopher; Mee, Christopher J.; Turek, Marine; Gorke, Sebastian; Royer, Cathy; Fischer, Benoit; Zahid, Muhammad N.; Lavillette, Dimitri; Fresquet, Judith; Cosset, François-Loïc; Rothenberg, S Michael; Pietschmann, Thomas; Patel, Arvind H.; Pessaux, Patrick; Doffoël, Michel; Raffelsberger, Wolfgang; Poch, Olivier; Mckeating, Jane A.; Brino, Laurent; Baumert, Thomas F.

    2011-01-01

    Hepatitis C virus (HCV) is a major cause of liver disease. Therapeutic options are limited and preventive strategies are absent. Entry is the first step of infection and requires the cooperative interaction of several host cell factors. Using a functional RNAi kinase screen we identified epidermal growth factor receptor and ephrin receptor A2 as host co-factors for HCV entry. Blocking of kinase function by approved inhibitors broadly inhibited HCV infection of all major HCV genotypes and viral escape variants in cell culture and an animal model in vivo. Receptor tyrosine kinases (RTKs) mediate HCV entry by regulating CD81-claudin-1 co-receptor associations and membrane fusion. These results identify RTKs as novel HCV entry co-factors and uncover that kinase inhibitors have significant antiviral activity. Inhibition of RTK function may constitute a novel approach for prevention and treatment of HCV infection. PMID:21516087

  11. Discovery and optimization of potent and selective functional antagonists of the human adenosine A2B receptor.

    Science.gov (United States)

    Bedford, Simon T; Benwell, Karen R; Brooks, Teresa; Chen, Ijen; Comer, Mike; Dugdale, Sarah; Haymes, Tim; Jordan, Allan M; Kennett, Guy A; Knight, Anthony R; Klenke, Burkhard; LeStrat, Loic; Merrett, Angela; Misra, Anil; Lightowler, Sean; Padfield, Anthony; Poullennec, Karine; Reece, Mark; Simmonite, Heather; Wong, Melanie; Yule, Ian A

    2009-10-15

    We herein report the discovery of a novel class of antagonists of the human adenosine A2B receptor. This low molecular weight scaffold has been optimized to offer derivatives with potential utility for the alleviation of conditions associated with this receptor subtype, such as nociception, diabetes, asthma and COPD. Furthermore, preliminary pharmacokinetic analysis has revealed compounds with profiles suitable for either inhaled or systemic routes of administration.

  12. Comparison of human recombinant adenosine A2B receptor function assessed by Fluo-3-AM fluorometry and microphysiometry.

    Science.gov (United States)

    Patel, H; Porter, R H P; Palmer, A M; Croucher, M J

    2003-02-01

    1. The aim of this study was to establish the utility of a fluorometric imaging plate reader (FLIPR) assay to assess human adenosine A(2B) receptor function by characterizing its receptor pharmacology and comparing this profile to that obtained using a microphysiometer. 2. FLIPR was used, in conjunction with a Ca(2+)-sensitive dye (Fluo-3-AM), to measure rapid rises in intracellular calcium in a Chinese Hamster Ovary (CHO-K1) cell line stably transfected with both the human A(2B) receptor and a promiscuous G(alpha16) protein. Microphysiometry was used to measure rapid changes in the rate of extracellular acidification in a Human Embryonic Kidney (HEK-293) cell line also stably transfected with human A(2B) receptor. 3. Activation of A(2B) receptors by various ligands caused a concentration-dependent increase in both the intracellular calcium concentration and the extracellular acidification rate in the cells tested, with a similar rank order of potency for agonists: NECA > N(6)-Benzyl NECA > adenosine > or = R-PIA > CPA > S-PIA > CHA > CGS 21680. No comparable effects were observed in the non-transfected control cell lines. 4. The rank order of potency of the agonists examined was the same in all studies, whereas absolute potency and efficacy varied. Thus, all compounds exhibited greater potency in FLIPR than the microphysiometer and the efficacies obtained with CHO-K1 + G(alpha16) + A(2B) cell line and FLIPR were greater than those obtained with HEK-293 + A(2B) cell line in the microphysiometer. 5. ZM-241385 was the most potent of a range of adenosine antagonists tested with a pA(2) of 8.0 in both the FLIPR and microphysiometer assays. 6. In conclusion, the profile of the responses to both A(2B) receptor agonists and antagonists in FLIPR were similar to those obtained by the microphysiometer, although both potency and efficacy values were higher in the FLIPR assay. With this caveat in mind, this study shows that FLIPR coupled with a cell line transfected with both

  13. Non-genomic actions of aldosterone: From receptors and signals to membrane targets.

    LENUS (Irish Health Repository)

    2012-02-01

    In tissues which express the mineralocorticoid receptor (MR), aldosterone modulates the expression of membrane targets such as the subunits of the epithelial Na(+) channel, in combination with important signalling intermediates such as serum and glucocorticoid-regulated kinase-1. In addition, the rapid \\'non-genomic\\' activation of protein kinases and secondary messenger signalling cascades has also been detected in aldosterone-sensitive tissues of the nephron, distal colon and cardiovascular system. These rapid actions are variously described as being coupled to MR or to an as yet unidentified, membrane-associated aldosterone receptor. The rapidly activated signalling cascades add a level of fine-tuning to the activity of aldosterone-responsive membrane transporters and also modulate the aldosterone-induced changes in gene expression through receptor and transcription factor phosphorylation.

  14. Non-genomic actions of aldosterone: From receptors and signals to membrane targets.

    LENUS (Irish Health Repository)

    Dooley, Ruth

    2011-07-26

    In tissues which express the mineralocorticoid receptor (MR), aldosterone modulates the expression of membrane targets such as the subunits of the epithelial Na(+) channel, in combination with important signalling intermediates such as serum and glucocorticoid-regulated kinase-1. In addition, the rapid \\'non-genomic\\' activation of protein kinases and secondary messenger signalling cascades has also been detected in aldosterone-sensitive tissues of the nephron, distal colon and cardiovascular system. These rapid actions are variously described as being coupled to MR or to an as yet unidentified, membrane-associated aldosterone receptor. The rapidly activated signalling cascades add a level of fine-tuning to the activity of aldosterone-responsive membrane transporters and also modulate the aldosterone-induced changes in gene expression through receptor and transcription factor phosphorylation.

  15. Toll-like receptor modulation in cardiovascular disease: a target for intervention?

    Science.gov (United States)

    Földes, Gábor; von Haehling, Stephan; Anker, Stefan D

    2006-08-01

    Toll-like receptors (TLRs) form a family of pattern recognition receptors that have emerged as key mediators of innate immunity. These receptors sense invading microbes and initiate the immune response. TLR-mediated inflammation is an important pathogenic link between innate immunity and a diverse panel of clinical disorders. Among the processes in which TLRs play a role are cardiovascular disorders such as cardiac ischaemia, coronary artery disease, ventricular remodelling, cancer angiogenesis or transplant rejection. From these, many important opportunities for disease modification through TLR signalling manipulation can be imagined. Their role as potential targets for therapeutic intervention is just beginning to be appreciated and this article reviews the current status of these treatment strategies for cardiovascular disease.

  16. Membrane omega-3 fatty acids modulate the oligomerisation kinetics of adenosine A2A and dopamine D2 receptors

    Science.gov (United States)

    Guixà-González, Ramon; Javanainen, Matti; Gómez-Soler, Maricel; Cordobilla, Begoña; Domingo, Joan Carles; Sanz, Ferran; Pastor, Manuel; Ciruela, Francisco; Martinez-Seara, Hector; Selent, Jana

    2016-01-01

    Membrane levels of docosahexaenoic acid (DHA), an essential omega-3 polyunsaturated fatty acid (ω-3 PUFA), are decreased in common neuropsychiatric disorders. DHA modulates key cell membrane properties like fluidity, thereby affecting the behaviour of transmembrane proteins like G protein-coupled receptors (GPCRs). These receptors, which have special relevance for major neuropsychiatric disorders have recently been shown to form dimers or higher order oligomers, and evidence suggests that DHA levels affect GPCR function by modulating oligomerisation. In this study, we assessed the effect of membrane DHA content on the formation of a class of protein complexes with particular relevance for brain disease: adenosine A2A and dopamine D2 receptor oligomers. Using extensive multiscale computer modelling, we find a marked propensity of DHA for interaction with both A2A and D2 receptors, which leads to an increased rate of receptor oligomerisation. Bioluminescence resonance energy transfer (BRET) experiments performed on living cells suggest that this DHA effect on the oligomerisation of A2A and D2 receptors is purely kinetic. This work reveals for the first time that membrane ω-3 PUFAs play a key role in GPCR oligomerisation kinetics, which may have important implications for neuropsychiatric conditions like schizophrenia or Parkinson’s disease.

  17. When cytokinin, a plant hormone, meets the adenosine A2A receptor: a novel neuroprotectant and lead for treating neurodegenerative disorders?

    Directory of Open Access Journals (Sweden)

    Yi-Chao Lee

    Full Text Available It is well known that cytokinins are a class of phytohormones that promote cell division in plant roots and shoots. However, their targets, biological functions, and implications in mammalian systems have rarely been examined. In this study, we show that one cytokinin, zeatin riboside, can prevent pheochromocytoma (PC12 cells from serum deprivation-induced apoptosis by acting on the adenosine A(2A receptor (A(2A-R, which was blocked by an A(2A-R antagonist and a protein kinase A (PKA inhibitor, demonstrating the functional ability of zeatin riboside by mediating through A(2A-R signaling event. Since the A(2A-R was implicated as a therapeutic target in treating Huntington's disease (HD, a cellular model of HD was applied by transfecting mutant huntingtin in PC12 cells. By using filter retardation assay and confocal microscopy we found that zeatin riboside reversed mutant huntingtin (Htt-induced protein aggregations and proteasome deactivation through A(2A-R signaling. PKA inhibitor blocked zeatin riboside-induced suppression of mutant Htt aggregations. In addition, PKA activated proteasome activity and reduced mutant Htt protein aggregations. However, a proteasome inhibitor blocked both zeatin riboside-and PKA activator-mediated suppression of mutant Htt aggregations, confirming mediation of the A(2A-R/PKA/proteasome pathway. Taken together, zeatin riboside might have therapeutic potential as a novel neuroprotectant and a lead for treating neurodegenerative disorders.

  18. Serine protease Omi/HtrA2 targets WARTS kinase to control cell proliferation.

    Science.gov (United States)

    Kuninaka, S; Iida, S-I; Hara, T; Nomura, M; Naoe, H; Morisaki, T; Nitta, M; Arima, Y; Mimori, T; Yonehara, S; Saya, H

    2007-04-12

    The serine protease Omi/HtrA2 was initially regarded as a proapoptotic molecule that proteolyses several proteins to induce cell death. Recent studies, however, indicate that loss of Omi protease activity increases susceptibility to stress-induced cell death. These complicated findings suggest that the protease activity of Omi is involved not only in apoptosis but also in cellular homeostasis. However, the targets which Omi uses to mediate this novel process are unknown. Previously, we showed that WARTS (WTS)/large tumor-suppressor 1 mitotic kinase interacts with the protein/discs-large protein/zonula (PDZ) domain of Omi and promotes its protease activity. We now report that WTS is a substrate for Omi protease activity, thus it is not only a regulator but also a downstream target of this protease. Interaction with Omi PDZ domain is required for WTS to be proteolysed. When caspase-9-deficient mouse embryonic fibroblasts (MEFs) were treated with staurosporine, WTS was proteolysed by activated endogenous Omi without induction of cell death. Therefore, protease activity of Omi and proteolysis of WTS are not necessarily required for cell death. We found that depletion of Omi from HeLa cells results in accelerated cell proliferation despite no significant change in the duration of mitosis. The depletion of WTS showed the same effect on S phase progression. Therefore, WTS proteolytic fragment(s) generated by Omi may act as an inhibitor of G1/S progression. Our data reveal a role for Omi-mediated processing of WTS in negative regulation of cell cycle progression at interphase, suggesting a novel function of Omi other than apoptosis.

  19. The complex role of multivalency in nanoparticles targeting the transferrin receptor for cancer therapies.

    Science.gov (United States)

    Wang, Jin; Tian, Shaomin; Petros, Robby A; Napier, Mary E; Desimone, Joseph M

    2010-08-18

    Transferrin receptor (TfR, CD71) has long been a therapeutic target due to its overexpression in many malignant tissues. In this study, PRINT() nanoparticles were conjugated with TfR ligands for targeted drug delivery. Cylindrical poly(ethylene glycol)-based PRINT nanoparticles (diameter (d) = 200 nm, height (h) = 200 nm) labeled with transferrin receptor antibody (NP-OKT9) or human transferrin (NP-hTf) showed highly specific TfR-mediated uptake by all human tumor cell lines tested, relative to negative controls (IgG1 for OKT9 or bovine transferrin (bTf) for hTf). The targeting efficiency was dependent on particle concentration, ligand density, dosing time, and cell surface receptor expression level. Interestingly, NP-OKT9 or NP-hTf showed little cytotoxicity on all solid tumor cell lines tested but were very toxic to Ramos B-cell lymphoma, whereas free OKT9 or hTf was not toxic. There was a strong correlation between TfR ligand density on the particle surface and cell viability and particle uptake. NP-OKT9 and NP-hTf were internalized into acidic intracellular compartments but were not localized in EEA1-enriched early endosomes or lysosomes. Elevated caspase 3/7 activity indicates activation of apoptosis pathways upon particle treatment. Supplementation of iron suppressed the toxicity of NP-OKT9 but not NP-hTf, suggesting different mechanisms by which NP-hTf and NP-OKT9 exerts cytotoxicity on Ramos cells. On the basis of such an observation, the complex role of multivalency in nanoparticles is discussed. In addition, our data clearly reveal that one must be careful in making claims of "lack of toxicity" when a targeting molecule is used on nanoparticles and also raise concerns for unanticipated off-target effects when one is designing targeted chemotherapy nanodelivery agents.

  20. Neuroprotection by caffeine in the MPTP model of parkinson's disease and its dependence on adenosine A2A receptors.

    Science.gov (United States)

    Xu, K; Di Luca, D G; Orrú, M; Xu, Y; Chen, J-F; Schwarzschild, M A

    2016-05-13

    Considerable epidemiological and laboratory data have suggested that caffeine, a nonselective adenosine receptor antagonist, may protect against the underlying neurodegeneration of parkinson's disease (PD). Although both caffeine and more specific antagonists of the A2A subtype of adenosine receptor (A2AR) have been found to confer protection in animal models of PD, the dependence of caffeine's neuroprotective effects on the A2AR is not known. To definitively determine its A2AR dependence, the effect of caffeine on 1-methyl-4-phenyl-1,2,3,6 tetra-hydropyridine (MPTP) neurotoxicity was compared in wild-type (WT) and A2AR gene global knockout (A2A KO) mice, as well as in central nervous system (CNS) cell type-specific (conditional) A2AR knockout (cKO) mice that lack the receptor either in postnatal forebrain neurons or in astrocytes. In WT and in heterozygous A2AR KO mice caffeine pretreatment (25mg/kgip) significantly attenuated MPTP-induced depletion of striatal dopamine. By contrast in homozygous A2AR global KO mice caffeine had no effect on MPTP toxicity. In forebrain neuron A2AR cKO mice, caffeine lost its locomotor stimulant effect, whereas its neuroprotective effect was mostly preserved. In astrocytic A2AR cKO mice, both caffeine's locomotor stimulant and protective properties were undiminished. Taken together, these results indicate that neuroprotection by caffeine in the MPTP model of PD relies on the A2AR, although the specific cellular localization of these receptors remains to be determined.

  1. Targeting of liposomes to HIV-1-infected cells by peptides derived from the CD4 receptor.

    Science.gov (United States)

    Slepushkin, V A; Salem, I I; Andreev, S M; Dazin, P; Düzgüneş, N

    1996-10-23

    Liposomes can be targeted to HIV-infected cells by either reconstituting transmembrane CD4 in the membrane or covalently coupling soluble CD4 to modified lipids. We investigated whether synthetic peptides could be used as ligands for targeting liposomes. A synthetic peptide from the complementarity determining region 2 (CDR-2)-like domain of CD4 could bind specifically to HIV-infected cells and mediate the binding of peptide-coupled liposomes to these cells. A peptide from the CDR-3-like domain of CD4 inhibited HIV-induced syncytia formation, but failed to target liposomes to infected cells. This apparent discrepancy may be due to the requirement for a conformational change in the CD4 receptor for the CDR-3 region to interact with the HIV envelope protein. Our results demonstrate the feasibility of using synthetic peptides to target liposomes containing antiviral drugs to HIV-infected cells.

  2. Transferrin receptor-targeted theranostic gold nanoparticles for photosensitizer delivery in brain tumors

    Science.gov (United States)

    Dixit, Suraj; Novak, Thomas; Miller, Kayla; Zhu, Yun; Kenney, Malcolm E.; Broome, Ann-Marie

    2015-01-01

    Therapeutic drug delivery across the blood-brain barrier (BBB) is not only inefficient, but also nonspecific to brain stroma. These are major limitations in the effective treatment of brain cancer. Transferrin peptide (Tfpep) targeted gold nanoparticles (Tfpep-Au NPs) loaded with the photodynamic pro-drug, Pc 4, have been designed and compared with untargeted Au NPs for delivery of the photosensitizer to brain cancer cell lines. In vitro studies of human glioma cancer lines (LN229 and U87) overexpressing the transferrin receptor (TfR) show a significant increase in cellular uptake for targeted conjugates as compared to untargeted particles. Pc 4 delivered from Tfpep-Au NPs clusters within vesicles after targeting with the Tfpep. Pc 4 continues to accumulate over a 4 hour period. Our work suggests that TfR-targeted Au NPs may have important therapeutic implications for delivering brain tumor therapies and/or providing a platform for noninvasive imaging.

  3. Optical control of endogenous receptors and cellular excitability using targeted covalent photoswitches.

    Science.gov (United States)

    Izquierdo-Serra, Mercè; Bautista-Barrufet, Antoni; Trapero, Ana; Garrido-Charles, Aida; Díaz-Tahoces, Ariadna; Camarero, Nuria; Pittolo, Silvia; Valbuena, Sergio; Pérez-Jiménez, Ariadna; Gay, Marina; García-Moll, Alejandro; Rodríguez-Escrich, Carles; Lerma, Juan; de la Villa, Pedro; Fernández, Eduardo; Pericàs, Miquel À; Llebaria, Amadeu; Gorostiza, Pau

    2016-07-20

    Light-regulated drugs allow remotely photoswitching biological activity and enable plausible therapies based on small molecules. However, only freely diffusible photochromic ligands have been shown to work directly in endogenous receptors and methods for covalent attachment depend on genetic manipulation. Here we introduce a chemical strategy to covalently conjugate and photoswitch the activity of endogenous proteins and demonstrate its application to the kainate receptor channel GluK1. The approach is based on photoswitchable ligands containing a short-lived, highly reactive anchoring group that is targeted at the protein of interest by ligand affinity. These targeted covalent photoswitches (TCPs) constitute a new class of light-regulated drugs and act as prosthetic molecules that photocontrol the activity of GluK1-expressing neurons, and restore photoresponses in degenerated retina. The modularity of TCPs enables the application to different ligands and opens the way to new therapeutic opportunities.

  4. Targeted Drug Delivery via Folate Receptors for the Treatment of Brain Cancer: Can the Promise Deliver?

    Science.gov (United States)

    Guo, Jianfeng; Schlich, Michele; Cryan, John F; O'Driscoll, Caitriona M

    2017-08-24

    Brain cancers are among the most lethal tumors due to their rapid development and poor prognosis. Despite the existing potential of novel therapeutic strategies for the treatment of brain cancer, the major remaining challenge associated with clinical translation is the lack of effective and safe delivery strategies to ensure drug transport to tumor tissues following systemic administration. Folate receptors, known to overexpress on different types of cancer cells, have been used to develop targeted delivery of therapeutic agents for cancer therapy. In this review, the potential of exploiting the folate receptor to achieve targeted cell-specific delivery of nanoparticles containing brain cancer therapeutics will be discussed in tandem with an analysis of the possible reasons for the current lack of clinical translation. Copyright © 2017. Published by Elsevier Inc.

  5. Label-free integrative pharmacology on-target of drugs at the β2-adrenergic receptor

    Science.gov (United States)

    Ferrie, Ann M.; Sun, Haiyan; Fang, Ye

    2011-07-01

    We describe a label-free integrative pharmacology on-target (iPOT) method to assess the pharmacology of drugs at the β2-adrenergic receptor. This method combines dynamic mass redistribution (DMR) assays using an array of probe molecule-hijacked cells with similarity analysis. The whole cell DMR assays track cell system-based, ligand-directed, and kinetics-dependent biased activities of the drugs, and translates their on-target pharmacology into numerical descriptors which are subject to similarity analysis. We demonstrate that the approach establishes an effective link between the label-free pharmacology and in vivo therapeutic indications of drugs.

  6. Epidermal Growth Factor Receptor Overexpression as a Target for Auger Electron Radiotherapy of Breast Cancer

    Science.gov (United States)

    1999-08-01

    buffer containing 200 mM sucrose/3 mM calcium chloride/50 mM Tris hydrochloride pH 7.6, followed by a wash step in 140 mM sodium chloride/10 mM Tris...in the sheep . J Endocrinol 1989; 123:121-130. 24. Duncan JR and Welch MJ. Intracellular metabolism of indium-111-DTPA labeled receptor targeted...car- the potential of glycosylated albumin in targeting intraperitoneal (i.p.) tu- bohydrate ligands (glucarate and gluconate ) for tumors and sites of

  7. Type I IL-1 Receptor (IL-1RI as Potential New Therapeutic Target for Bronchial Asthma

    Directory of Open Access Journals (Sweden)

    Jyh-Hong Lee

    2010-01-01

    Full Text Available The IL-1R/TLR family has been receiving considerable attention as potential regulators of inflammation through their ability to act as either activators or suppressors of inflammation. Asthma is a chronic inflammatory disease characterized by airway hyperresponsiveness, allergic inflammation, elevated serum total, allergen-specific IgE levels, and increased Th2 cytokine production. The discovery that the IL-1RI–IL-1 and ST2–IL-33 pathways are crucial for allergic inflammation has raised interest in these receptors as potential targets for developing new therapeutic strategies for bronchial asthma. This paper discusses the current use of neutralizing mAb or soluble receptor constructs to deplete cytokines, the use of neutralizing mAb or recombinant receptor antagonists to block cytokine receptors, and gene therapy from experimental studies in asthma. Targeting IL-1RI–IL-1 as well as ST2–IL-33 pathways may promise a disease-modifying approach in the future.

  8. The Nuclear Hormone Receptor PPARγ as a Therapeutic Target in Major Diseases

    Directory of Open Access Journals (Sweden)

    Martina Victoria Schmidt

    2010-01-01

    Full Text Available The peroxisome proliferator-activated receptor γ (PPARγ belongs to the nuclear hormone receptor superfamily and regulates gene expression upon heterodimerization with the retinoid X receptor by ligating to peroxisome proliferator response elements (PPREs in the promoter region of target genes. Originally, PPARγ was identified as being essential for glucose metabolism. Thus, synthetic PPARγ agonists, the thiazolidinediones (TZDs, are used in type 2 diabetes therapy as insulin sensitizers. More recent evidence implied an important role for the nuclear hormone receptor PPARγ in controlling various diseases based on its anti-inflammatory, cell cycle arresting, and proapoptotic properties. In this regard, expression of PPARγ is not restricted to adipocytes, but is also found in immune cells, such as B and T lymphocytes, monocytes, macrophages, dendritic cells, and granulocytes. The expression of PPARγ in lymphoid organs and its modulation of macrophage inflammatory responses, lymphocyte proliferation, cytokine production, and apoptosis underscore its immune regulating functions. Moreover, PPARγ expression is found in tumor cells, where its activation facilitates antitumorigenic actions. This review provides an overview about the role of PPARγ as a possible therapeutic target approaching major, severe diseases, such as sepsis, cancer, and atherosclerosis.

  9. G-Protein-Coupled Receptors: Next Generation Therapeutic Targets in Head and Neck Cancer?

    Directory of Open Access Journals (Sweden)

    Takeharu Kanazawa

    2015-08-01

    Full Text Available Therapeutic outcome in head and neck squamous cell carcinoma (HNSCC is poor in most advanced cases. To improve therapeutic efficiency, novel therapeutic targets and prognostic factors must be discovered. Our studies have identified several G protein-coupled receptors (GPCRs as promising candidates. Significant epigenetic silencing of GPCR expression occurs in HNSCC compared with normal tissue, and is significantly correlated with clinical behavior. Together with the finding that GPCR activity can suppress tumor cell growth, this indicates that GPCR expression has potential utility as a prognostic factor. In this review, we discuss the roles that galanin receptor type 1 (GALR1 and type 2 (GALR2, tachykinin receptor type 1 (TACR1, and somatostatin receptor type 1 (SST1 play in HNSCC. GALR1 inhibits proliferation of HNSCC cells though ERK1/2-mediated effects on cell cycle control proteins such as p27, p57, and cyclin D1, whereas GALR2 inhibits cell proliferation and induces apoptosis in HNSCC cells. Hypermethylation of GALR1, GALR2, TACR1, and SST1 is associated with significantly reduced disease-free survival and a higher recurrence rate. Although their overall activities varies, each of these GPCRs has value as both a prognostic factor and a therapeutic target. These data indicate that further study of GPCRs is a promising strategy that will enrich pharmacogenomics and prognostic research in HNSCC.

  10. Computational design of trimeric influenza-neutralizing proteins targeting the hemagglutinin receptor binding site

    Energy Technology Data Exchange (ETDEWEB)

    Strauch, Eva-Maria; Bernard, Steffen M.; La, David; Bohn, Alan J.; Lee, Peter S.; Anderson, Caitlin E.; Nieusma, Travis; Holstein, Carly A.; Garcia, Natalie K.; Hooper, Kathryn A.; Ravichandran, Rashmi; Nelson, Jorgen W.; Sheffler, William; Bloom, Jesse D.; Lee, Kelly K.; Ward, Andrew B.; Yager, Paul; Fuller, Deborah H.; Wilson, Ian A.; Baker , David (UWASH); (Scripps); (FHCRC)

    2017-06-12

    Many viral surface glycoproteins and cell surface receptors are homo-oligomers1, 2, 3, 4, and thus can potentially be targeted by geometrically matched homo-oligomers that engage all subunits simultaneously to attain high avidity and/or lock subunits together. The adaptive immune system cannot generally employ this strategy since the individual antibody binding sites are not arranged with appropriate geometry to simultaneously engage multiple sites in a single target homo-oligomer. We describe a general strategy for the computational design of homo-oligomeric protein assemblies with binding functionality precisely matched to homo-oligomeric target sites5, 6, 7, 8. In the first step, a small protein is designed that binds a single site on the target. In the second step, the designed protein is assembled into a homo-oligomer such that the designed binding sites are aligned with the target sites. We use this approach to design high-avidity trimeric proteins that bind influenza A hemagglutinin (HA) at its conserved receptor binding site. The designed trimers can both capture and detect HA in a paper-based diagnostic format, neutralizes influenza in cell culture, and completely protects mice when given as a single dose 24 h before or after challenge with influenza.

  11. Steroid hormone receptors and prostate cancer: role of structural dynamics in therapeutic targeting

    Directory of Open Access Journals (Sweden)

    Raj Kumar

    2016-01-01

    Full Text Available Steroid hormone receptors (SHRs act in cell type- and gene-specific manner through interactions with coregulatory proteins to regulate numerous physiological and pathological processes at the level of gene regulation. Binding of steroid receptor modulator (SRM ligand leads to allosteric changes in SHR to exert positive or negative effects on the expression of target genes. Due, in part, to the fact that current SRMs generally target ligand binding domain (LBD/AF2 and neglect intrinsically disordered (ID N-terminal domain (NTD/AF1, clinically relevant SRMs lack selectivity and are also prone to the development of resistance over time. Therefore, to maximize the efficacy of SHR-based therapeutics, the possibility of developing unique modulators that act to control AF1 activity must be considered. Recent studies targeting androgen receptor′s (AR′s ID AF1 domain for the castration-resistant prostate cancer has provided the possibility of therapeutically targeting ID NTD/AF1 surfaces by allosteric modulations to achieve desired effects. In this review article, we discuss how inter- and intra- molecular allosteric regulations controlled by AR′s structural flexibility and dynamics particularly the ID NTD/AF1 is an emerging area of investigation, which could be exploited for drug development and therapeutic targeting of prostate cancer.

  12. Primary vitamin D receptor target genes as biomarkers for the vitamin D3 status in the hematopoietic system.

    Science.gov (United States)

    Wilfinger, Julia; Seuter, Sabine; Tuomainen, Tomi-Pekka; Virtanen, Jyrki K; Voutilainen, Sari; Nurmi, Tarja; de Mello, Vanessa D F; Uusitupa, Matti; Carlberg, Carsten

    2014-08-01

    Vitamin D(3) belongs to the few nutritional compounds that has, via the binding of its metabolite 1α,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3)) to the transcription factor vitamin D receptor (VDR), a direct effect on gene regulation. The relation of thousands of genomic VDR-binding sites to a few hundred primary 1,25(OH)(2)D(3) target genes is still largely unresolved. We studied chromatin domains containing genes for the adhesion molecules CD97 and LRRC8A, the glucose transporter SLC37A2 and the coactivator NRIP1. These domains vary significantly in size (7.3 to 956 kb) but contain each one major VDR-binding site. In monocytic cells these four sites are associated with open chromatin and occupied by VDR, while in macrophage-like cells only the sites of LRRC8A, SLC37A2 and NRIP1 are accessible and receptor bound. The VDR site of CD97 does, in contrast to the three other loci, not carry any DR3-type binding sequence. CD97, LRRC8A, SLC37A2 and NRIP1 are early responding 1,25(OH)(2)D(3) target genes in monocytic cells, while in macrophage-like cells they respond less and, in part, delayed. In primary human peripheral blood mononuclear cells from 71 prediabetic subjects of a vitamin D(3) intervention study (VitDmet) CD97, LRRC8A, SLC37A2 and NRIP1 can be used as transcriptomic biomarkers for classifying human individuals for their possible benefit from vitamin D(3) supplementation. In particular, NRIP1 exceeds the potential of the previously identified marker CD14 by more than 40% and seems to be a well-suited molecular marker for the vitamin D(3) status in the hematopoietic system.

  13. Cardiac N-methyl D-aspartate receptors as a pharmacological target

    OpenAIRE

    Makhro, Asya; Tian, Qinghai; Kaestner, Lars; Kosenkov, Dmitry; Faggian, Giuseppe; Gassmann, Max; Schwarzwald, Colin; BOGDANOVA, Anna

    2016-01-01

    This study focuses on characterization of the cardiac N-methyl D-aspartate receptors (NMDARs) as a target for endogenous and synthetic agonists and antagonists. Using isolated perfused rat hearts, we have shown that intracoronary administration of the NMDAR agonists and antagonists has a pronounced effect on autonomous heart function. Perfusion of rat hearts with autologous blood supplemented with NMDAR agonists was associated with induction of tachycardia, sinus arrhythmia and ischemia occur...

  14. Peroxisome Proliferator Activated Receptor A Ligands as Anticancer Drugs Targeting Mitochondrial Metabolism

    OpenAIRE

    Grabacka, Maja; Pierzchalska, Malgorzata; Reiss, Krzysztof

    2013-01-01

    Tumor cells show metabolic features distinctive from normal tissues, with characteristically enhanced aerobic glycolysis, glutaminolysis and lipid synthesis. Peroxisome proliferator activated receptor α (PPAR α) is activated by nutrients (fatty acids and their derivatives) and influences these metabolic pathways acting antagonistically to oncogenic Akt and c-Myc. Therefore PPAR α can be regarded as a candidate target molecule in supplementary anticancer pharmacotherapy as well as dietary ther...

  15. Targeting Ligand-Dependent and Ligand-Independent Androgen Receptor Signaling in Prostate Cancer

    Science.gov (United States)

    2015-10-01

    Award Number: W81XWH-12-1-0288 TITLE: Targeting Ligand-Dependent and Ligand-Independent Androgen Receptor Signaling in Prostate Cancer...average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed...and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of

  16. Role of chemokines and their receptors in chronic lymphocytic leukemia: function in microenvironment and targeted therapy.

    Science.gov (United States)

    Han, Ting-Ting; Fan, Lei; Li, Jian-Yong; Xu, Wei

    2014-01-01

    Chemokines produced in distinct tissue microenvironments sustain migration of mature lymphocytes in lymphoglandula. Chemokine receptors expressed on chronic lymphocytic leukemia (CLL) cells regulate the migration of the leukemia cells within the bone marrow (BM), lymphoid organs in collaboration with chemokines. Chemokines form a pro-survival circuitry by regulating leukocyte trafficking, maintaining extended lymphocyte survival. Therefore, chemokines in tumor cell-microenvironment interactions represent a target for treatment of CLL. AMD3100 disrupts the CLL/microenvironment interactions and influences CXCL12/CXCR4 survival signaling. Fostamatinib, ibrutinib, and GS-1101 as B-cell receptor (BCR)-related kinase inhibitors inhibit BCR- and chemokine-receptor-signal-regulated kinase and have a good clinical response in CLL. Lenalidomide, sorafenib, and dasatinib are other additional drugs associated with chemokine in microenvironment. Inhibiting signaling through chemokine and microenvironment associated signaling are emerging as innovative therapeutic targets in CLL. In this article, we reviewed the role of chemokines in CLL microenvironment and novel therapeutics targeting CLL microenvironment.

  17. Targeting and retention of type 1 ryanodine receptors to the endoplasmic reticulum.

    Science.gov (United States)

    Meur, Gargi; Parker, Andrew K T; Gergely, Fanni V; Taylor, Colin W

    2007-08-10

    Most ryanodine receptors and their relatives, inositol 1,4,5-trisphosphate receptors, are expressed in the sarcoplasmic or endoplasmic reticulum (ER), where they mediate Ca(2+) release. We expressed fragments of ryanodine receptor type 1 (RyR1) in COS cells alone or fused to intercellular adhesion molecule-1 (ICAM-1), each tagged with yellow fluorescent protein, and used confocal imaging and glycoprotein analysis to identify the determinants of ER targeting and retention. Single transmembrane domains (TMD) of RyR1 taken from the first (TMD1-TMD2) or last (TMD5-TMD6) pair were expressed in the ER membrane. TMD3-TMD4 was expressed in the outer mitochondrial membrane. The TMD outer pairs (TMD1-TMD2 and TMD5-TMD6) retained ICAM-1, a plasma membrane-targeted protein, within the ER membrane. TMD1 alone provided a strong ER retention signal and TMD6 a weaker signal, but the other single TMD were unable to retain ICAM-1 in the ER. We conclude that TMD1 provides the first and sufficient signal for ER targeting of RyR1. The TMD outer pairs include redundant ER retention signals, with TMD1 providing the strongest signal.

  18. Peroxisome proliferator-activated receptors as transcriptional nodal points and therapeutic targets.

    Science.gov (United States)

    Brown, Jonathan D; Plutzky, Jorge

    2007-01-30

    Peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors involved in the transcriptional regulation of key metabolic pathways such as lipid metabolism, adipogenesis, and insulin sensitivity. More recent work implicates all 3 PPAR isotypes (alpha, gamma, and delta, also known as beta or beta/delta) in inflammatory and atherosclerotic pathways. Because these nuclear receptors are activated by extracellular signals and control multiple gene targets, PPARs can be seen as nodes that control multiple inputs and outputs involved in energy balance, providing insight into how metabolism and the vasculature may be integrated. The ongoing clinical use of fibrates, which activate PPARalpha, and thiazolidinediones, which activate PPARgamma, establishes these receptors as viable drug targets, whereas considerable in vitro animal model and human surrogate marker studies suggest that PPAR activation may limit inflammation and atherosclerosis. Together, these various observations have stimulated intense interest in PPARs as therapeutic targets and led to large-scale cardiovascular end-point trials with PPAR agonists. The first of these studies has generated mixed results that require careful review, especially in anticipation of additional clinical trial data and ongoing attempts to develop novel PPAR modulators. Such analysis of the existing PPAR data, the appropriate use of currently approved PPAR agonists, and continued progress in PPAR therapeutics will be predicated on a better understanding of PPAR biology.

  19. Enigma (partially) resolved: phospholipase A2 receptor is the cause of "idiopathic" membranous glomerulonephritis.

    Science.gov (United States)

    Truong, Luan D; Seshan, Surya V

    2015-12-15

    Membranous glomerulonephritis (MGN) is a very significant kidney disease. It is one of the frequent causes of heavy protein excretion in urine. MGN is thought to be an immune-mediated disease caused by glomerular deposition of antigen-antibody complexes. The pathogenic antigen, however, has been an enigma until recently. It was discovered in 2009 that phospholipase A2 receptor (PLA2R), a normal transmembrane protein in podocyte plasma membrane, is the antigen causing MGN. Within 5 yr of its discovery, this seminal finding has leaded to novel insights into the treatment of this disease including diagnosis, therapy, and prediction of outcome. This finding also paves the way for fundamental studies on how and why autoimmunity against PLA2R develops. The discovery of PLA2A as the cause of "idiopathic" MGN after a half century of speculation, followed by further fundamental insights with such an expedient and successful application in patient care, embodies the elegance of science at its junction with society. This perspective traces the story of this remarkable discovery.

  20. Phospholipase A2-modified low-density lipoprotein activates macrophage peroxisome proliferator-activated receptors.

    Science.gov (United States)

    Namgaladze, Dmitry; Morbitzer, Daniel; von Knethen, Andreas; Brüne, Bernhard

    2010-02-01

    Peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors modulating metabolic and inflammatory responses of phagocytes to stimuli such as fatty acids and their metabolites. We studied the role of PPARs in macrophages exposed to low-density lipoprotein (LDL) modified by secretory phospholipase A(2) (PLA). By analyzing PPAR ligand-binding domain luciferase reporter activation, we observed that PLA-LDL transactivates PPARalpha and PPARdelta, but not PPARgamma. We confirmed that PLA-LDL induced PPAR response element reporter activation by endogenous PPARalpha and PPARdelta in human THP-1 macrophages. By using THP-1 cells with a stable knockdown of PPARalpha and PPARdelta, we showed that PLA-LDL-activated PPARdelta altered macrophage gene expression related to lipid metabolism and lipid droplet formation. Although PPARalpha/delta silencing did not affect cholesterol and triglyceride accumulation in PLA-LDL-treated macrophages, PPARdelta activation by PLA-LDL attenuated macrophage inflammatory gene expression induced by interferon gamma and lipopolysaccharide. PPARdelta activation by PLA-LDL does not influence lipid accumulation in PLA-LDL-treated macrophages. However, it attenuates macrophage inflammatory responses, thus contributing to an anti-inflammatory cell phenotype.

  1. Prostaglandin E2 and the EP receptors in malignancy: possible therapeutic targets?

    Science.gov (United States)

    O'Callaghan, G

    2015-01-01

    Abstract Elevated expression of COX‐2 and increased levels of PGE2 are found in numerous cancers and are associated with tumour development and progression. Although epidemiological, clinical and preclinical studies have shown that the inhibition of PGE2 synthesis through the use of either non‐steroidal anti‐inflammatory drugs (NSAIDs) or specific COX‐2 inhibitors (COXibs) has the potential to prevent and treat malignant disease, toxicities due to inhibition of COX‐2 have limited their use. Thus, there is an urgent need for the development of strategies whereby COX‐2 activity may be reduced without inducing any side effects. The biological effects of PGE2 are mediated by signalling through four distinct E‐type prostanoid (EP) receptors – EP1, EP2, EP3 and EP4. In recent years, extensive effort has gone into elucidating the function of PGE2 and the EP receptors in health and disease, with the goal of creating selective inhibitors as a means of therapy. In this review, we focus on PGE2, and in particular on the role of the individual EP receptors and their signalling pathways in neoplastic disease. As knowledge concerning the role of the EP receptors in cancer grows, so does the potential for exploiting the EP receptors as therapeutic targets for the treatment of cancer and metastatic disease. PMID:26377664

  2. The Prelude on Novel Receptor and Ligand Targets Involved in the Treatment of Diabetes Mellitus

    Directory of Open Access Journals (Sweden)

    Venu Gopal Jonnalagadda

    2014-05-01

    Full Text Available Metabolic disorders are a group of disorders, due to the disruption of the normal metabolic process at a cellular level. Diabetes Mellitus and Tyrosinaemia are the majorly reported metabolic disorders. Among them, Diabetes Mellitus is a one of the leading metabolic syndrome, affecting 5 to 7 % of the population worldwide and mainly characterised by elevated levels of glucose and is associated with two types of physiological event disturbances such as impaired insulin secretion and insulin resistance. Up to now, various treatment strategies are like insulin, alphaglucosidase inhibitors, biguanides, incretins were being followed. Concurrently, various novel therapeutic strategies are required to advance the therapy of Diabetes mellitus. For the last few decades, there has been an extensive research in understanding the metabolic pathways involved in Diabetes Mellitus at the cellular level and having the profound knowledge on cell-growth, cell-cycle, and apoptosis at a molecular level provides new targets for the treatment of Diabetes Mellitus. Receptor signalling has been involved in these mechanisms, to translate the information coming from outside. To understand the various receptors involved in these pathways, we must have a sound knowledge on receptors and ligands involved in it. This review mainly summarises the receptors and ligands which are involved the Diabetes Mellitus. Finally, researchers have to develop the alternative chemical moieties that retain their affinity to receptors and efficacy. Diabetes Mellitus being a metabolic disorder due to the glucose surfeit, demands the need for regular exercise along with dietary changes.

  3. Frizzled7: A Promising Achilles’ Heel for Targeting the Wnt Receptor Complex to Treat Cancer

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    Toby Phesse

    2016-05-01

    Full Text Available Frizzled7 is arguably the most studied member of the Frizzled family, which are the cognate Wnt receptors. Frizzled7 is highly conserved through evolution, from Hydra through to humans, and is expressed in diverse organisms, tissues and human disease contexts. Frizzled receptors can homo- or hetero-polymerise and associate with several co-receptors to transmit Wnt signalling. Notably, Frizzled7 can transmit signalling via multiple Wnt transduction pathways and bind to several different Wnt ligands, Frizzled receptors and co-receptors. These promiscuous binding and functional properties are thought to underlie the pivotal role Frizzled7 plays in embryonic developmental and stem cell function. Recent studies have identified that Frizzled7 is upregulated in diverse human cancers, and promotes proliferation, progression and invasion, and orchestrates cellular transitions that underscore cancer metastasis. Importantly, Frizzled7 is able to regulate Wnt signalling activity even in cancer cells which have mutations to down-stream signal transducers. In this review we discuss the various aspects of Frizzled7 signalling and function, and the implications these have for therapeutic targeting of Frizzled7 in cancer.

  4. The histamine H3 receptor: an attractive target for the treatment of cognitive disorders.

    Science.gov (United States)

    Esbenshade, T A; Browman, K E; Bitner, R S; Strakhova, M; Cowart, M D; Brioni, J D

    2008-07-01

    The histamine H3 receptor, first described in 1983 as a histamine autoreceptor and later shown to also function as a heteroreceptor that regulates the release of other neurotransmitters, has been the focus of research by numerous laboratories as it represents an attractive drug target for a number of indications including cognition. The purpose of this review is to acquaint the reader with the current understanding of H3 receptor localization and function as a modulator of neurotransmitter release and its effects on cognitive processes, as well as to provide an update on selected H3 antagonists in various states of preclinical and clinical advancement. Blockade of centrally localized H3 receptors by selective H3 receptor antagonists has been shown to enhance the release of neurotransmitters such as histamine, ACh, dopamine and norepinephrine, among others, which play important roles in cognitive processes. The cognitive-enhancing effects of H3 antagonists across multiple cognitive domains in a wide number of preclinical cognition models also bolster confidence in this therapeutic approach for the treatment of attention deficit hyperactivity disorder, Alzheimer's disease and schizophrenia. However, although a number of clinical studies examining the efficacy of H3 receptor antagonists for a variety of cognitive disorders are currently underway, no clinical proof of concept for an H3 receptor antagonist has been reported to date. The discovery of effective H3 antagonists as therapeutic agents for the novel treatment of cognitive disorders will only be accomplished through continued research efforts that further our insights into the functions of the H3 receptor.

  5. Structural basis for bitter taste receptor activation and its potential role in targeting diabetes

    Directory of Open Access Journals (Sweden)

    Ravinder Abrol

    2015-03-01

    Full Text Available Background: Taste receptors are G protein-coupled receptors that, besides being present in the taste buds, have also been shown to be present in the gastrointestinal (GI system, respiratory system, and brain, though their function at these locations is not well understood. Objective: To understand the nutrient mediated release of gut peptides like GLP-1 from enteroendocrine L-cells of the GI system, we focused on a bitter taste receptor TAS2R38 (based on animal models to investigate the structural basis of its potential role in the release of gut peptides. Methods: The atomic-level structure of bitter taste receptor TAS2R38 was predicted using GEnSeMBLE, a first-principle based GPCR structure prediction method. These structures were obtained for the dominant taster haplotype (PAV as well as for the nontaster haplotype (AVI of the receptor. The known ligands phenylthiocarbamide (PTC and 6-n-propylthiouracil (PTU were docked to these structures to provide a structural basis for the taster and nontaster haplotypes. Results: Docking of known ligands PTU and PTC to taster and nontaster haplotypes of the bitter taste receptor showed a backbone hydrogen bond to residue 262 in taster but not in nontaster haplotype, suggesting a potential mode of action of these molecules in the activation of the bitter taste receptor. Conclusion: These results, combined with the ability of PTC to release gut peptides from in vitro models of the enteroendocrine L-cells, suggest a potential structural basis for TAS2R38 activation that can lead to the release of those peptides. This release has a therapeutic benefit for type 2 diabetes and implies a role for bitter tasting (but safe natural compounds targeting TAS2R38 as potential drug candidates for curing type 2 diabetes.

  6. TRA-418, a thromboxane A2 receptor antagonist and prostacyclin receptor agonist, inhibits platelet-leukocyte interaction in human whole blood.

    Science.gov (United States)

    Miyamoto, Mitsuko; Ohno, Michihiro; Yamada, Naohiro; Ohtake, Atsushi; Matsushita, Teruo

    2010-10-01

    TRA-418, a compound with both thromboxane A2 receptor (TP receptor) antagonistic and prostacyclin receptor (IP receptor) agonistic activities, was synthesised in our laboratory as a new antithrombotic agent. In this study, we examined the effects of TRA-418 on platelet-leukocyte interactions in human whole blood. Platelet-leukocyte interactions were induced by U-46619 in the presence of epinephrine (U-46619 + epinephrine) or with thrombin receptor agonist peptide 1-6 (TRAP). Platelet-leukocyte interactions were assessed by flow cytometry, with examination of both platelet-neutrophil and platelet-monocyte complexes. In a control experiment, the TP receptor antagonist SQ-29548 significantly inhibited the induction of platelet-leukocyte complexes by the combination of U-46619 and epinephrine, but not TRAP-induced formation of platelet-leukocyte complexes. Conversely, the IP receptor agonist beraprost sodium inhibited platelet-leukocyte complex formation induced by both methods, although the IC50 values of beraprost sodium for U-46619 + epinephrine were at least 10-fold greater than for TRAP. Under such conditions, TRA-418 inhibited both U-46619 + epinephrine-induced and TRAP-induced platelet-leukocyte complex formation in a concentration-dependent manner, in a similar range. These results suggest that TRA-418 exerts its inhibitory effects on platelet-leukocyte interactions by acting as a TP receptor antagonist as well as an IP receptor agonist in an additive or synergistic manner. These inhibitory effects of TRA-418 on formation of platelet-leukocyte complexes suggest the compound is beneficial effects as an antithrombotic agent.

  7. Potential of the cannabinoid CB(2) receptor as a pharmacological target against inflammation in Parkinson's disease.

    Science.gov (United States)

    Gómez-Gálvez, Yolanda; Palomo-Garo, Cristina; Fernández-Ruiz, Javier; García, Concepción

    2016-01-04

    Inflammation is an important pathogenic factor in Parkinson's disease (PD), so that it can contribute to kill dopaminergic neurons of the substantia nigra and to enhance the dopaminergic denervation of the striatum. The cannabinoid type-2 (CB2) receptor has been investigated as a potential anti-inflammatory and neuroprotective target in different neurodegenerative disorders, but still limited evidence has been collected in PD. Here, we show for the first time that CB2 receptors are elevated in microglial cells recruited and activated at lesioned sites in the substantia nigra of PD patients compared to control subjects. Parkinsonian inflammation can be reproduced experimentally in rodents by intrastriatal injections of lipopolysaccharide (LPS) which, through an intense activation of glial elements and peripheral infiltration, provokes a rapid deterioration of the striatum that may extend to the substantia nigra too. Using this experimental model, we recently described a much more intense deterioration of tyrosine hydroxylase (TH)-containing nigral neurons in CB2 receptor-deficient mice compared to wild-type animals, supporting a potential neuroprotective role for this receptor. In the present study, we further explored this issue. First, we found elevated levels of the CB2 receptor measured by qRT-PCR in the striatum and substantia nigra of LPS-lesioned mice, as well as an increase in the immunostaining for this receptor in the LPS-lesioned striatum. Second, we found a significant increase in CD68 immunostaining, which serve to identify activated microglia and also infiltrated peripheral macrophages, in these brain structures in response to LPS insult, which was much more intense in CB2 receptor-deficient mice in the case of the substantia nigra. Next, we observed that the activation of CB2 receptors with a selective agonist (HU-308) reversed LPS-induced elevation of CD68 immunostaining in the striatum and the parallel reduction in TH immunostaining. Lastly, we

  8. Targeting receptor for advanced glycation end products (RAGE) expression induces apoptosis and inhibits prostate tumor growth

    Energy Technology Data Exchange (ETDEWEB)

    Elangovan, Indira; Thirugnanam, Sivasakthivel; Chen, Aoshuang; Zheng, Guoxing [Department of Biomedical Sciences, University of Illinois, College of Medicine, Rockford, IL 61107 (United States); Bosland, Maarten C.; Kajdacsy-Balla, Andre [Department of Pathology, University of Illinois at Chicago, Chicago, IL 60612 (United States); Gnanasekar, Munirathinam, E-mail: mgnanas@uic.edu [Department of Biomedical Sciences, University of Illinois, College of Medicine, Rockford, IL 61107 (United States)

    2012-01-27

    Highlights: Black-Right-Pointing-Pointer Targeting RAGE by RNAi induces apoptosis in prostate cancer cells. Black-Right-Pointing-Pointer Silencing RAGE expression abrogates rHMGB1 mediated cell proliferation. Black-Right-Pointing-Pointer Down regulation of RAGE by RNAi inhibits PSA secretion of prostate cancer cells. Black-Right-Pointing-Pointer Knock down of RAGE abrogates prostate tumor growth in vivo. Black-Right-Pointing-Pointer Disruption of RAGE expression in prostate tumor activates death receptors. -- Abstract: Expression of receptor for advanced glycation end products (RAGE) plays a key role in the progression of prostate cancer. However, the therapeutic potential of targeting RAGE expression in prostate cancer is not yet evaluated. Therefore in this study, we have investigated the effects of silencing the expression of RAGE by RNAi approach both in vitro and in vivo. The results of this study showed that down regulation of RAGE expression by RNAi inhibited the cell proliferation of androgen-dependent (LNCaP) and androgen-independent (DU-145) prostate cancer cells. Furthermore, targeting RAGE expression resulted in apoptotic elimination of these prostate cancer cells by activation of caspase-8 and caspase-3 death signaling. Of note, the levels of prostate specific antigen (PSA) were also reduced in LNCaP cells transfected with RAGE RNAi constructs. Importantly, the RAGE RNAi constructs when administered in nude mice bearing prostate tumors, inhibited the tumor growth by targeting the expression of RAGE, and its physiological ligand, HMGB1 and by up regulating death receptors DR4 and DR5 expression. Collectively, the results of this study for the first time show that targeting RAGE by RNAi may be a promising alternative therapeutic strategy for treating prostate cancer.

  9. Cholinergic nicotinic receptor genes implicated in a nicotine dependence association study targeting 348 candidate genes with 3713 SNPs.

    Science.gov (United States)

    Saccone, Scott F; Hinrichs, Anthony L; Saccone, Nancy L; Chase, Gary A; Konvicka, Karel; Madden, Pamela A F; Breslau, Naomi; Johnson, Eric O; Hatsukami, Dorothy; Pomerleau, Ovide; Swan, Gary E; Goate, Alison M; Rutter, Joni; Bertelsen, Sarah; Fox, Louis; Fugman, Douglas; Martin, Nicholas G; Montgomery, Grant W; Wang, Jen C; Ballinger, Dennis G; Rice, John P; Bierut, Laura Jean

    2007-01-01

    Nicotine dependence is one of the world's leading causes of preventable death. To discover genetic variants that influence risk for nicotine dependence, we targeted over 300 candidate genes and analyzed 3713 single nucleotide polymorphisms (SNPs) in 1050 cases and 879 controls. The Fagerström test for nicotine dependence (FTND) was used to assess dependence, in which cases were required to have an FTND of 4 or more. The control criterion was strict: control subjects must have smoked at least 100 cigarettes in their lifetimes and had an FTND of 0 during the heaviest period of smoking. After correcting for multiple testing by controlling the false discovery rate, several cholinergic nicotinic receptor genes dominated the top signals. The strongest association was from an SNP representing CHRNB3, the beta3 nicotinic receptor subunit gene (P = 9.4 x 10(-5)). Biologically, the most compelling evidence for a risk variant came from a non-synonymous SNP in the alpha5 nicotinic receptor subunit gene CHRNA5 (P = 6.4 x 10(-4)). This SNP exhibited evidence of a recessive mode of inheritance, resulting in individuals having a 2-fold increase in risk of developing nicotine dependence once exposed to cigarette smoking. Other genes among the top signals were KCNJ6 and GABRA4. This study represents one of the most powerful and extensive studies of nicotine dependence to date and has found novel risk loci that require confirmation by replication studies.

  10. Adenoviruses using the cancer marker EphA2 as a receptor in vitro and in vivo by genetic ligand insertion into different capsid scaffolds.

    Directory of Open Access Journals (Sweden)

    Michael Behr

    Full Text Available Adenoviral gene therapy and oncolysis would critically benefit from targeted cell entry by genetically modified capsids. This requires both the ablation of native adenovirus tropism and the identification of ligands that remain functional in virus context. Here, we establish cell type-specific entry of HAdV-5-based vectors by genetic ligand insertion into a chimeric fiber with shaft and knob domains of the short HAdV-41 fiber (Ad5T/41sSK. This fiber format was reported to ablate transduction in vitro and biodistribution to the liver in vivo. We show that the YSA peptide, binding to the pan-cancer marker EphA2, can be inserted into three positions of the chimeric fiber, resulting in strong transduction of EphA2-positive but not EphA2-negative cells of human melanoma biopsies and of tumor xenografts after intratumoral injection. Transduction was blocked by soluble YSA peptide and restored for EphA2-negative cells after recombinant EphA2 expression. The YSA peptide could also be inserted into three positions of a CAR binding-ablated HAdV-5 fiber enabling specific transduction; however, the Ad5T/41sSK format was superior in vivo. In conclusion, we establish an adenovirus capsid facilitating functional insertion of targeting peptides and a novel adenovirus using the tumor marker EphA2 as receptor with high potential for cancer gene therapy and viral oncolysis.

  11. Activating and deactivating mutations in the receptor interaction site of GDF5 cause symphalangism or brachydactyly type A2

    DEFF Research Database (Denmark)

    Seemann, Petra; Schwappacher, Raphaela; Kjær, Klaus Wilbrandt

    2005-01-01

    Here we describe 2 mutations in growth and differentiation factor 5 (GDF5) that alter receptor-binding affinities. They cause brachydactyly type A2 (L441P) and symphalangism (R438L), conditions previously associated with mutations in the GDF5 receptor bone morphogenetic protein receptor type 1b...... activity when compared with WT GDF5. Biosensor interaction analyses revealed loss of binding to BMPR1A and BMPR1B ectodomains for the L441P mutant, whereas the R438L mutant showed normal binding to BMPR1B but increased binding to BMPR1A, the receptor normally activated by BMP2. The binding to NOGGIN...... was normal for both mutants. Thus, the brachydactyly type A2 phenotype (L441P) is caused by inhibition of the ligand-receptor interaction, whereas the symphalangism phenotype (R438L) is caused by a loss of receptor-binding specificity, resulting in a gain of function by the acquisition of BMP2-like...

  12. Pharmacologic suppression of target cell recognition by engineered T cells expressing chimeric T-cell receptors.

    Science.gov (United States)

    Alvarez-Vallina, L; Yañez, R; Blanco, B; Gil, M; Russell, S J

    2000-04-01

    Adoptive therapy with autologous T cells expressing chimeric T-cell receptors (chTCRs) is of potential interest for the treatment of malignancy. To limit possible T-cell-mediated damage to normal tissues that weakly express the targeted tumor antigen (Ag), we have tested a strategy for the suppression of target cell recognition by engineered T cells. Jurkat T cells were transduced with an anti-hapten chTCR tinder the control of a tetracycline-suppressible promoter and were shown to respond to Ag-positive (hapten-coated) but not to Ag-negative target cells. The engineered T cells were then reacted with hapten-coated target cells at different effector to target cell ratios before and after exposure to tetracycline. When the engineered T cells were treated with tetracycline, expression of the chTCR was greatly decreased and recognition of the hapten-coated target cells was completely suppressed. Tetracycline-mediated suppression of target cell recognition by engineered T cells may be a useful strategy to limit the toxicity of the approach to cancer gene therapy.

  13. Prolactinoma ErbB receptor expression and targeted therapy for aggressive tumors.

    Science.gov (United States)

    Cooper, Odelia; Mamelak, Adam; Bannykh, Serguei; Carmichael, John; Bonert, Vivien; Lim, Stephen; Cook-Wiens, Galen; Ben-Shlomo, Anat

    2014-06-01

    As ErbB signaling is a determinant of prolactin synthesis, role of ErbB receptors was tested for prolactinoma outcomes and therapy. The objective of this study was to characterize ErbB receptor expression in prolactinomas and then perform a pilot study treating resistant prolactinomas with a targeted tyrosine kinase inhibitor (TKI). Retrospective analysis of prolactinomas and pilot study for dopamine agonist resistant prolactinomas in tertiary referral center. We performed immunofluorescent staining of a tissue array of 29 resected prolactinoma tissues for EGFR, ErbB2, ErbB3, and ErbB4 correlated with clinical features. Two patients with aggressive resistant prolactinomas enrolled and completed trial. They received lapatinib 1,250 mg daily for 6 months with tumor and hormone assessments. Main outcome measures were positive tumor staining of respective ErbB receptors, therapeutic reduction of prolactin levels and tumor shrinkage. Treated PRL levels and tumor volumes were suppressed in both subjects treated with TKI. EGFR expression was positive in 82 % of adenomas, ErbB2 in 92 %, ErbB3 in 25 %, and ErbB4 in 71 %, with ErbB2 score > EGFR > ErbB4 > ErbB3. Higher ErbB3 expression was associated with optic chiasm compression (p = 0.03), suprasellar extension (p = 0.04), and carotid artery encasement (p = 0.01). Higher DA response rates were observed in tumors with higher ErbB3 expression. Prolactinoma expression of specific ErbB receptors is associated with tumor invasion, symptoms, and response to dopamine agonists. Targeting ErbB receptors may be effective therapy in patients with resistant prolactinomas.

  14. In vivo photoacoustic molecular imaging of breast carcinoma with folate receptor-targeted indocyanine green nanoprobes.

    Science.gov (United States)

    Wang, Huina; Liu, Chengbo; Gong, Xiaojing; Hu, Dehong; Lin, Riqiang; Sheng, Zonghai; Zheng, Cuifang; Yan, Meng; Chen, Jingqin; Cai, Lintao; Song, Liang

    2014-11-06

    As an optical-acoustic hybrid imaging technology, photoacoustic imaging uniquely combines the advantages of rich optical contrast with high ultrasonic resolution in depth, opening up many new possibilities not attainable with conventional pure optical imaging technologies. To perform photoacoustic molecular imaging, optically absorbing exogenous contrast agents are needed to enhance the signals from specifically targeted disease activity. In this work, we designed and developed folate receptor targeted, indocyanine green dye doped poly(d,l-lactide-co-glycolide) lipid nanoparticles (FA-ICG-PLGA-lipid NPs) for molecular photoacoustic imaging of tumor. The fabricated FA-ICG-PLGA-lipid NPs exhibited good aqueous stability, a high folate-receptor targeting efficiency, and remarkable optical absorption in near-infrared wavelengths, providing excellent photoacoustic signals in vitro. Furthermore, after intravenous administration of FA-ICG-PLGA-lipid NPs, mice bearing MCF-7 breast carcinomas showed significantly enhanced photoacoustic signals in vivo in the tumor regions, compared with those using non-targeted ICG-PLGA-lipid NPs. Given the existing wide clinical use of ICG and PLGA, the developed FA-ICG-PLGA-lipid NPs, in conjunction with photoacoustic imaging technology, offer a great potential to be translated into the clinic for non-ionizing molecular imaging of breast cancer in vivo.

  15. Peptide Phage Display as a Tool for Drug Discovery: Targeting Membrane Receptors

    Directory of Open Access Journals (Sweden)

    Tomaz Bratkovic

    2011-01-01

    Full Text Available Ligands selected from phage-displayed random peptide libraries tend to be directed to biologically relevant sites on the surface of the target protein. Consequently, peptides derived from library screenings often modulate the target protein’s activity in vitro and in vivo and can be used as lead compounds in drug design and as alternatives to antibodies for target validation in both genomics and drug discovery. This review discusses the use of phage display to identify membrane receptor modulators with agonistic or antagonistic activities. Because isolating or producing recombinant membrane proteins for use as target molecules in library screening is often impossible, innovative selection strategies such as panning against whole cells or tissues, recombinant receptor ectodomains, or neutralizing antibodies to endogenous binding partners were devised. Prominent examples from a two-decade history of peptide phage display will be presented, focusing on the design of affinity selection experiments, methods for improving the initial hits, and applications of the identified peptides.

  16. In vivo photoacoustic molecular imaging of breast carcinoma with folate receptor-targeted indocyanine green nanoprobes

    Science.gov (United States)

    Wang, Huina; Liu, Chengbo; Gong, Xiaojing; Hu, Dehong; Lin, Riqiang; Sheng, Zonghai; Zheng, Cuifang; Yan, Meng; Chen, Jingqin; Cai, Lintao; Song, Liang

    2014-11-01

    As an optical-acoustic hybrid imaging technology, photoacoustic imaging uniquely combines the advantages of rich optical contrast with high ultrasonic resolution in depth, opening up many new possibilities not attainable with conventional pure optical imaging technologies. To perform photoacoustic molecular imaging, optically absorbing exogenous contrast agents are needed to enhance the signals from specifically targeted disease activity. In this work, we designed and developed folate receptor targeted, indocyanine green dye doped poly(d,l-lactide-co-glycolide) lipid nanoparticles (FA-ICG-PLGA-lipid NPs) for molecular photoacoustic imaging of tumor. The fabricated FA-ICG-PLGA-lipid NPs exhibited good aqueous stability, a high folate-receptor targeting efficiency, and remarkable optical absorption in near-infrared wavelengths, providing excellent photoacoustic signals in vitro. Furthermore, after intravenous administration of FA-ICG-PLGA-lipid NPs, mice bearing MCF-7 breast carcinomas showed significantly enhanced photoacoustic signals in vivo in the tumor regions, compared with those using non-targeted ICG-PLGA-lipid NPs. Given the existing wide clinical use of ICG and PLGA, the developed FA-ICG-PLGA-lipid NPs, in conjunction with photoacoustic imaging technology, offer a great potential to be translated into the clinic for non-ionizing molecular imaging of breast cancer in vivo.

  17. Treatment of pancreatic cancer with epidermal growth factor receptor-targeted therapy

    Directory of Open Access Journals (Sweden)

    Bryan A Faller

    2009-09-01

    Full Text Available Bryan A Faller, Barbara BurtnessDepartment of Medical Oncology, Fox Chase Cancer Center, Philadelphia, PA, USAAbstract: Pancreatic adenocarcinoma is a common malignancy that remains refractory to available therapies. Gemcitabine has long been the standard, first-line agent in advanced disease. The epidermal growth factor receptor (EGFR is a commonly expressed target in pancreatic cancer that is involved in tumor proliferation, metastasis, and induction of angiogenesis. The addition of the EGFR inhibitor erlotinib to gemcitabine has recently been demonstrated to provide a small, yet statistically significant, survival benefit in advanced disease. This has prompted further research into the applications of EGFR-targeted therapy in pancreatic cancer, albeit with disappointing results. Resistance to these therapies seems highly prevalent and has been implicated in their limited efficacy. The development of rash is associated with treatment efficacy and suggests that predictive factors may one day be identified to guide appropriate patient selection for these agents. Preclinical research has shown promise that resistance to EGFR-targeted therapies can be overcome through a variety of approaches. Application of this research in clinical trials may ultimately yield an unquestioned role for EGFR-targeted therapy in the management of this disease.Keywords: cetuximab, drug resistance, epidermal growth factor receptor, erlotinib, gemcitabine, pancreatic cancer

  18. Targeting Nuclear Receptors with Lentivirus-Delivered Small RNAs in Primary Human Hepatocytes

    Directory of Open Access Journals (Sweden)

    Maria Thomas

    2014-07-01

    Full Text Available Background: RNA interference (RNAi has tremendous potential for investigating gene function and for developing new therapies. Primary human hepatocytes (PHH are the “gold standard” for studying the regulation of hepatic metabolism in vitro. However, application of RNAi in PHH has some technical hurdles. The objective of this study was to develop effective and robust protocol for transduction of PHH with lentiviral vectors. Methods: We used lentiviral vectors to transduce PHH for introduction of short hairpin RNAs (shRNAs targeting constitutive androstane receptor (CAR, peroxisome proliferator activated receptor alpha (PPARα, and microRNA, miR-143. Infection efficiency was quantitatively analyzed by flow cytometry and microscopy. Target gene expression was assessed using quantitative real-time (qRT-PCR method. Results: Lentiviral vector transduction resulted in ≥95% of infected cells at low multiplicity of infection (MOI of 3, which did not impair cellular viability. We demonstrated the feasibility of this technique in studies on targeting nuclear receptors, PPARα and CAR, with shRNAs as well as in lentivirus-mediated overexpression and knock-down of miRNA-143 experiments. Conclusions: We developed an efficient and robust protocol with standardized procedures for virus production, method of titer determination, and infection procedure for RNAi in primary human hepatocytes based on delivery of shRNAs, microRNAs or anti-microRNAs in different laboratory settings. This approach should be useful to study not only the regulation via nuclear receptors but also other biological, pharmacological, and toxicological aspects of drug metabolism.

  19. An anti-phospholipase A2 receptor quantitative immunoassay and epitope analysis in membranous nephropathy reveals different antigenic domains of the receptor.

    Science.gov (United States)

    Behnert, Astrid; Fritzler, Marvin J; Teng, Beina; Zhang, Meifeng; Bollig, Frank; Haller, Hermann; Skoberne, Andrej; Mahler, Michael; Schiffer, Mario

    2013-01-01

    The phospholipase A2 receptor (PLA2R) was recently discovered as a target autoantigen in patients with idiopathic membranous nephropathy (IMN). Published evidence suggests that the autoantibodies directed towards a conformation dependent epitope are currently effectively detected by a cell based assay (CBA) utilizing indirect immunofluorescence (IIF) on tissue culture cells transfected with the PLA2R cDNA. Limitations of such IIF-CBA assays include observer dependent subjective evaluation of semi-quantitative test results and the protocols are not amenable to high throughput diagnostic testing. We developed a quantitative, observer independent, high throughput capture immunoassay for detecting PLA2R autoantibodies on an addressable laser bead immunoassay (ALBIA) platform. Since reactive domains of PLA2R (i.e. epitopes) could be used to improve diagnostic tests by using small peptides in various high throughput diagnostic platforms, we identified PLA2R epitopes that bound autoantibodies of IMN patients. These studies confirmed that inter-molecular epitope spreading occurs in IMN but use of the cognate synthetic peptides in immunoassays was unable to conclusively distinguish between IMN patients and normal controls. However, combinations of these peptides were able to effectively absorb anti-PLA2R reactivity in IIF-CBA and an immunoassay that employed a lysate derived from HEK cells tranfected with and overexpressing PLA2R. While we provide evidence of intermolecular epitope spreading, our data indicates that in addition to conformational epitopes, human anti-PLA2R reactivity in a commercially available CBA and an addressable laser bead immunoassay is significantly absorbed by peptides representing epitopes of PLA2R.

  20. An anti-phospholipase A2 receptor quantitative immunoassay and epitope analysis in membranous nephropathy reveals different antigenic domains of the receptor.

    Directory of Open Access Journals (Sweden)

    Astrid Behnert

    Full Text Available The phospholipase A2 receptor (PLA2R was recently discovered as a target autoantigen in patients with idiopathic membranous nephropathy (IMN. Published evidence suggests that the autoantibodies directed towards a conformation dependent epitope are currently effectively detected by a cell based assay (CBA utilizing indirect immunofluorescence (IIF on tissue culture cells transfected with the PLA2R cDNA. Limitations of such IIF-CBA assays include observer dependent subjective evaluation of semi-quantitative test results and the protocols are not amenable to high throughput diagnostic testing. We developed a quantitative, observer independent, high throughput capture immunoassay for detecting PLA2R autoantibodies on an addressable laser bead immunoassay (ALBIA platform. Since reactive domains of PLA2R (i.e. epitopes could be used to improve diagnostic tests by using small peptides in various high throughput diagnostic platforms, we identified PLA2R epitopes that bound autoantibodies of IMN patients. These studies confirmed that inter-molecular epitope spreading occurs in IMN but use of the cognate synthetic peptides in immunoassays was unable to conclusively distinguish between IMN patients and normal controls. However, combinations of these peptides were able to effectively absorb anti-PLA2R reactivity in IIF-CBA and an immunoassay that employed a lysate derived from HEK cells tranfected with and overexpressing PLA2R. While we provide evidence of intermolecular epitope spreading, our data indicates that in addition to conformational epitopes, human anti-PLA2R reactivity in a commercially available CBA and an addressable laser bead immunoassay is significantly absorbed by peptides representing epitopes of PLA2R.

  1. Differential role of nitric oxide in regional sympathetic responses to stimulation of NTS A2a adenosine receptors.

    Science.gov (United States)

    Scislo, Tadeusz J; Tan, Nobusuke; O'Leary, Donal S

    2005-02-01

    Our previous studies showed that preganglionic adrenal (pre-ASNA), renal (RSNA), lumbar, and postganglionic adrenal sympathetic nerve activities (post-ASNA) are inhibited after stimulation of arterial baroreceptors, nucleus of the solitary tract (NTS), and glutamatergic and P2x receptors and are activated after stimulation of adenosine A1 receptors. However, stimulation of adenosine A2a receptors inhibited RSNA and post-ASNA, whereas it activated pre-ASNA. Because the effects evoked by NTS A2a receptors may be mediated via activation of nitric oxide (NO) mechanisms in NTS neurons, we tested the hypothesis that NO synthase (NOS) inhibitors would attenuate regional sympathetic responses to NTS A2a receptor stimulation, whereas NO donors would evoke contrasting responses from pre-ASNA versus RSNA and post-ASNA. Therefore, in chloralose/urethane-anesthetized rats, we compared hemodynamic and regional sympathetic responses to microinjections of selective A2a receptor agonist (CGS-21680, 20 pmol/50 nl) after pretreatment with NOS inhibitors Nomega-nitro-L-arginine methyl ester (10 nmol/100 nl) and 1-[2-(trifluoromethyl)phenyl]imidazole (100 pmol/100 nl) versus pretreatment with vehicle (100 nl). In addition, responses to microinjections into the NTS of different NO donors [40 and 400 pmol/50 nl sodium nitroprusside (SNP); 0.5 and 5 nmol/50 nl 3,3-bis(aminoethyl)-1-hydroxy-2-oxo-1-triazene (DETA NONOate, also known as NOC-18), and 2 nmol/50 nl 3-(2-hydroxy-2-nitroso-1-propylhydrazino)-1-propanamine (PAPA NONOate, also known as NOC-15)], the NO precursor L-arginine (10-50 nmol/50 nl), and sodium glutamate (500 pmol/50 nl) were evaluated. SNP, DETA NONOate, and PAPA NONOate activated pre-ASNA and inhibited RSNA and post-ASNA, whereas l-arginine and glutamate microinjected into the same site of the NTS inhibited all these sympathetic outputs. Decreases in heart rate and depressor or biphasic responses accompanied the neural responses. Pretreatment with NOS inhibitors

  2. Impact of purification conditions and history on A2A adenosine receptor activity: The role of CHAPS and lipids.

    Science.gov (United States)

    Naranjo, Andrea N; McNeely, Patrick M; Katsaras, John; Robinson, Anne Skaja

    2016-08-01

    The adenosine A2A receptor (A2AR) is a much-studied class A G protein-coupled receptor (GPCR). For biophysical studies, A2AR is commonly purified in a detergent mixture of dodecylmaltoside (DDM), 3-(3-cholamidopropyl) dimethylammoniopropane sulfonate (CHAPS), and cholesteryl hemisuccinate (CHS). Here we studied the effects of CHAPS on the ligand binding activity and stability of wild type, full-length human A2AR. We also tested the cholesterol requirement for maintaining the active conformation of the receptor when solubilized in detergent micelles. To this end, the receptor was purified using DDM, DDM/CHAPS, or the short hydrocarbon chain lipid 1,2-dihexanoyl-sn-glycero-3-phosphocholine (DHPC, di-6:0PC). After solubilization in DDM, DDM/CHAPS, or DHPC micelles, although A2AR was found to retain its native-like fold, its binding ability was significantly compromised compared to DDM or DDM/CHAPS with CHS. It therefore appears that although cholesterol is not needed for A2AR to retain a native-like, α-helical conformation, it may be a critical component for high affinity ligand binding. Further, this result suggests that the conformational differences between the active and inactive protein may be so subtle that commonly used spectroscopic methods are unable to differentiate between the two forms, highlighting the need for activity measurements. The studies presented in this paper also underline the importance of the protein's purification history; i.e., detergents that interact with the protein during purification affect the ligand binding properties of the receptor in an irreversible manner. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Effect of phospholipid hydrolysis by phospholipase A2 on the kinetics of antagonist binding to cardiac muscarinic receptors.

    Science.gov (United States)

    Rauch, B; Niroomand, F; Messineo, F C; Weis, A; Kübler, W; Hasselbach, W

    1994-09-15

    Activation of phospholipases during prolonged myocardial ischemia could contribute to the functional derangement of myocardial cells by altering the phospholipid environment of a number of membrane bound proteins including receptors. The present study examined the kinetics of muscarinic receptor antagonist [3H]quinuclidinyl benzilate binding ([3H]QNB) to muscarinic receptors of highly purified sarcolemmal membranes under control conditions and after treatment with phospholipase A2 (PLA2; EC 3.1.1.4). Initial binding rates of QNB exhibited saturation kinetics, when plotted against the ligand concentration in control and PLA2 treated sarcolemmal membranes. This kinetic behaviour of QNB-binding is consistent with at least a two step binding mechanism. According to this two step binding hypothesis an unstable intermediate receptor-QNB complex (R*QNB) forms rapidly, and this form undergoes a slow conversion to the high affinity ligand-receptor complex R-QNB. The Michaelis constant Km of R-QNB formation was 1.8 nM, whereas the dissociation constant Kd obtained from equilibrium measurements was 0.062 nM. After 5 min exposure of sarcolemmal membranes to PLA2QNB binding capacity (Bmax) was reduced by 62%, and the affinity of the remaining receptor sites was decreased by 47% (Kd = 0.116 nM). This PLA2-induced increase of Kd was accompanied by a corresponding increase of Km, whereas the rate constants k2 and k-2 of the hypothetical slow conversion step (second reaction step) remained unchanged. These results suggest that binding of QNB to cardiac muscarinic receptors induces a transition in the receptor-ligand configuration, which is necessary for the formation of the final high affinity R-QNB complex. PLA2-induced changes of the lipid environment result in the inability of a part of the receptor population to undergo this transition, thereby inhibiting high affinity QNB-binding.

  4. Anti-Phospholipase A2 Receptor Antibodies in Recurrent Membranous Nephropathy

    Science.gov (United States)

    Kattah, Andrea; Ayalon, Rivka; Beck, Laurence H.; Sandor, Dana G.; Cosio, Fernando G.; Gandhi, Manish J.; Sethi, Sanjeev; Lorenz, Elizabeth C.; Salant, David J.; Fervenza, Fernando C.

    2015-01-01

    About 70% of patients with primary membranous nephropathy (MN) have circulating anti-phospholipase A2 receptor (PLA2R) antibodies that correlate with disease activity, but their predictive value in post-transplant (Tx) recurrent MN is uncertain. We evaluated 26 patients, 18 with recurrent MN and 8 without recurrence, with serial post-Tx serum samples and renal biopsies to determine if patients with pre-Tx anti-PLA2R are at increased risk of recurrence as compared to seronegative patients and to determine if post-Tx changes in anti-PLA2R correspond to the clinical course. In the recurrent group, 10/17 patients had anti-PLA2R at the time of Tx vs. 2/7 patients in the non-recurrent group. The positive predictive value of pre-Tx anti-PLA2R for recurrence was 83%, while the negative predictive value was 42%. Persistence or reappearance of post-Tx anti-PLA2R was associated with increasing proteinuria and resistant disease in many cases; little or no proteinuria occurred in cases with pre-Tx anti-PLA2R and biopsy evidence of recurrence in which the antibodies resolved with standard immunosuppression. Some cases with positive pre-Tx anti-PLA2R were seronegative at the time of recurrence. In conclusion, patients with positive pre-Tx anti-PLA2R should be monitored closely for recurrent MN. Persistence or reappearance of antibody post-Tx may indicate a more resistant disease. PMID:25766759

  5. Deficiency of phospholipase A2 receptor exacerbates ovalbumin-induced lung inflammation.

    Science.gov (United States)

    Tamaru, Shun; Mishina, Hideto; Watanabe, Yosuke; Watanabe, Kazuhiro; Fujioka, Daisuke; Takahashi, Soichiro; Suzuki, Koji; Nakamura, Takamitsu; Obata, Jun-Ei; Kawabata, Kenichi; Yokota, Yasunori; Murakami, Makoto; Hanasaki, Kohji; Kugiyama, Kiyotaka

    2013-08-01

    Secretory phospholipase A2 (sPLA2) plays a critical role in the genesis of lung inflammation through proinflammatory eicosanoids. A previous in vitro experiment showed a possible role of cell surface receptor for sPLA2 (PLA2R) in the clearance of extracellular sPLA2. PLA2R and groups IB and X sPLA2 are expressed in the lung. This study examined a pathogenic role of PLA2R in airway inflammation using PLA2R-deficient (PLA2R(-/-)) mice. Airway inflammation was induced by immunosensitization with OVA. Compared with wild-type (PLA2R(+/+)) mice, PLA2R(-/-) mice had a significantly greater infiltration of inflammatory cells around the airways, higher levels of groups IB and X sPLA2, eicosanoids, and Th2 cytokines, and higher numbers of eosinophils and neutrophils in bronchoalveolar lavage fluid after OVA treatment. In PLA2R(-/-) mice, intratracheally instilled [(125)I]-labeled sPLA2-IB was cleared much more slowly from bronchoalveolar lavage fluid compared with PLA2R(+/+) mice. The degradation of the instilled [(125)I]-labeled sPLA2-IB, as assessed by trichloroacetic acid-soluble radioactivity in bronchoalveolar lavage fluid after instillation, was lower in PLA2R(-/-) mice than in PLA2R(+/+) mice. In conclusion, PLA2R deficiency increased sPLA2-IB and -X levels in the lung through their impaired clearance from the lung, leading to exaggeration of lung inflammation induced by OVA treatment in a murine model.

  6. Autoantibodies against phospholipase A2 receptor in Korean patients with membranous nephropathy.

    Science.gov (United States)

    Oh, Yun Jung; Yang, Seung Hee; Kim, Dong Ki; Kang, Shin-Wook; Kim, Yon Su

    2013-01-01

    The data were presented in abstract form at the 45(th) meeting of the American Society of Nephrology, October 30-November 04 2012, San Diego, CA, USA. Circulating autoantibodies against M-type phospholipase A2 receptor (PLA2R) are important pathogenic antibodies of idiopathic membranous nephropathy (MN) in adults. However, previous studies on the clinical impact of anti-PLA2R antibodies demonstrated several limitations, including insufficient numbers of study subjects and different time points and methods for anti-PLA2R antibody measurement. To verify the clinical significance of anti-PLA2R antibodies in Korean patients with MN, we measured autoantibodies in serum samples obtained at the time of biopsy from a total of 100 patients with idiopathic MN who had not yet received immunosuppressive treatment. We detected anti-PLA2R antibody in 69 patients, and we observed that autoantibody reactivity reflected the severity of disease activity. Proteinuria and hypoalbuminemia were more severe in patients with anti-PLA2R than in those without the autoantibodies (2.95 g/g vs. 6.85 g/g, P = 0.003; 3.1 g/dL vs. 2.5 g/dL, P = 0.004, respectively). Additionally, the clinical severities worsened proportionally as the levels of anti-PLA2R antibodies increased (P = 0.015 and P for trend PLA2R antibody showed a significant correlation with clinical outcomes, such as remission rate and time to remission. In conclusion, we observed that anti-PLA2R antibodies are highly prevalent in Korean patients with idiopathic MN and that they reflect the clinical disease activity before the administration of immunosuppressive treatment. However, the levels of anti-PLA2R antibody at the time of kidney biopsy may not predict the clinical outcomes in current clinical practice.

  7. Anti-Phospholipase A2 Receptor Antibody Titer Predicts Post-Rituximab Outcome of Membranous Nephropathy.

    Science.gov (United States)

    Ruggenenti, Piero; Debiec, Hanna; Ruggiero, Barbara; Chianca, Antonietta; Pellé, Timothee; Gaspari, Flavio; Suardi, Flavio; Gagliardini, Elena; Orisio, Silvia; Benigni, Ariela; Ronco, Pierre; Remuzzi, Giuseppe

    2015-10-01

    Rituximab induces nephrotic syndrome (NS) remission in two-thirds of patients with primary membranous nephropathy (MN), even after other treatments have failed. To assess the relationships among treatment effect, circulating nephritogenic anti-phospholipase A2 receptor (anti-PLA2R) autoantibodies and genetic polymorphisms predisposing to antibody production we serially monitored 24-hour proteinuria and antibody titer in patients with primary MN and long-lasting NS consenting to rituximab (375 mg/m(2)) therapy and genetic analyses. Over a median (range) follow-up of 30.8 (6.0-145.4) months, 84 of 132 rituximab-treated patients achieved complete or partial NS remission (primary end point), and 25 relapsed after remission. Outcomes of patients with or without detectable anti-PLA2R antibodies at baseline were similar. Among the 81 patients with antibodies, lower anti-PLA2R antibody titer at baseline (P=0.001) and full antibody depletion 6 months post-rituximab (hazard ratio [HR], 7.90; 95% confidence interval [95% CI], 2.54 to 24.60; PPLA2R antibody depletion. On average, 50% anti-PLA2R titer reduction preceded equivalent proteinuria reduction by 10 months. Re-emergence of circulating antibodies predicted disease relapse (HR, 6.54; 95% CI, 1.57 to 27.40; P=0.01), whereas initial complete remission protected from the event (HR, 6.63; 95% CI, 2.37 to 18.53; PPLA2R1 and HLA-DQA1 polymorphisms and of previous immunosuppressive treatment. Therefore, assessing circulating anti-PLA2R autoantibodies and proteinuria may help in monitoring disease activity and guiding personalized rituximab therapy in nephrotic patients with primary MN.

  8. Thromboxane A(2 receptor stimulation promotes closure of the rat ductus arteriosus through enhancing neointima formation.

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    Tomohiro Yokota

    Full Text Available Ductus arteriosus (DA closure follows constriction and remodeling of the entire vessel wall. Patent ductus arteriosus occurs when the DA does not close after birth, and this condition is currently treated using cyclooxygenase inhibitors. However, the efficacy of cyclooxygenase inhibitors is often limited. Our previous study demonstrated that low-dose thromboxane A2 receptor (TP stimulation constricted the DA with minimal adverse effects in rat neonates. However, its effect on DA remodeling remains unknown. In this study, we focused on the impact of the exogenous TP stimulation on the DA remodeling, especially intimal thickening. Using DA explants from rat fetuses at embryonic day 19 as a ex vivo model and primary cultured rat DA smooth muscle cells from embryonic day 21 as a in vitro model, we evaluated the effect of TP stimulation on the DA remodeling. The selective TP agonists U46619 and I-BOP promoted neointima formation in the ex vivo DA explants, and TP stimulation increased DA SMC migration in a dose-dependent manner. Both effects were inhibited by the selective TP antagonist SQ29548 or the siRNA against TP. TP stimulation also increased DA SMC proliferation in the presence of 10% fetal bovine serum. LC/MS/MS analysis revealed that TP stimulation increased secretion of several extracellular matrix proteins that may contribute to an increase in neointima formation. In conclusion, we uncovered that exogenous administration of TP agonist promotes neointima formation through the induction of migration and proliferation of DA SMC, which could contribute to DA closure and also to its vasoconstrictive action.

  9. Synthesis and pharmacological characterization of novel xanthine carboxylate amides as A2A adenosine receptor ligands exhibiting bronchospasmolytic activity.

    Science.gov (United States)

    Yadav, Rakesh; Bansal, Ranju; Rohilla, Suman; Kachler, Sonja; Klotz, Karl-Norbert

    2016-04-01

    The carboxylate amides of 8-phenyl-1,3-dimethylxanthine described herein represent a new series of selective ligands of the adenosine A2A receptors exhibiting bronchospasmolytic activity. The effects of location of 8-phenyl substitutions on the adenosine receptor (AR) binding affinities of the newly synthesized xanthines have also been studied. The compounds displayed moderate to potent binding affinities toward various adenosine receptor subtypes when evaluated through radioligand binding studies. However, most of the compounds showed the maximum affinity for the A2A subtype, some with high selectivity versus all other subtypes. Xanthine carboxylate amide 13b with a diethylaminoethylamino moiety at the para-position of the 8-phenylxanthine scaffold was identified as the most potent A2A adenosine receptor ligand with Ki=0.06μM. Similarly potent and highly A2A-selective are the isovanillin derivatives 16a and 16d. In addition, the newly synthesized xanthine derivatives showed good in vivo bronchospasmolytic activity when tested in guinea pigs.

  10. Synthesis and Properties of a New Water-Soluble Prodrug of the Adenosine A2A Receptor Antagonist MSX-2

    Directory of Open Access Journals (Sweden)

    Christa E. Müller

    2008-02-01

    Full Text Available The compound L-valine-3-{8-[(E-2-[3-methoxyphenylethenyl]-7-methyl-1-propargylxanthine-3-yl}propyl ester hydrochloride (MSX-4 was synthesized as an aminoacid ester prodrug of the adenosine A2A receptor antagonist MSX-2. It was found to bestable in artificial gastric acid, but readily cleaved by pig liver esterase.

  11. Blunted dynamics of adenosine A2A receptors is associated with increased susceptibility to Candida albicans infection in the elderly

    Science.gov (United States)

    Rodrigues, Lisa; Miranda, Isabel M.; Andrade, Geanne M.; Mota, Marta; Cortes, Luísa; Rodrigues, Acácio G.; Cunha, Rodrigo A.; Gonçalves, Teresa

    2016-01-01

    Opportunistic gut infections and chronic inflammation, in particular due to overgrowth of Candida albicans present in the gut microbiota, are increasingly reported in the elder population. In aged, adult and young mice, we now compared the relative intestinal over-colonization by ingested C. albicans and their translocation to other organs, focusing on the role of adenosine A2A receptors that are a main stop signal of inflammation. We report that elderly mice are more prone to over-colonization by C. albicans than adult and young mice. This fungal over-growth seems to be related with higher growth rate in intestinal lumen, independent of gut tissues invasion, but resulting in higher GI tract inflammation. We observed a particularly high colonization of the stomach, with increased rate of yeast-to-hypha transition in aged mice. We found a correlation between A2A receptor density and tissue damage due to yeast infection: comparing with young and adults, aged mice have a lower gut A2A receptor density and C. albicans infection failed to increase it. In conclusion, this study shows that aged mice have a lower ability to cope with inflammation due to C. albicans over-colonization, associated with an inability to adaptively adjust adenosine A2A receptors density. PMID:27590517

  12. Targeting Thromboxane A2 Receptor for Anti-Metastasis Therapy of Breast Cancer

    Science.gov (United States)

    2011-09-01

    Focusing Tumor Microenvironment, Stem Cells and Metastasis 570 (MTOC) and Golgi apparatus to the front of the nucleus, oriented toward the direction of...movement. MTOC orientation at the leading edge then facilitates the delivery of Golgi derived vesicles to the leading edge and microtubule growth into

  13. Targeting Thromboxane A2 Receptor for Antimetastasis Therapy of Breast Cancer

    Science.gov (United States)

    2012-09-01

    Nie D and Zhang X. Use of Acetylsalicylic acid to reduce cancer metastasis. Disclosed to Technology Transfer office of Southern Illinois...surface. A polyclonal antibody raised against the N-terminal 120 amino acid residues of TP was used to stain live, non-permeabilized cells. As shown

  14. Targeting estrogen receptor β as preventive therapeutic strategy for Leber's hereditary optic neuropathy.

    Science.gov (United States)

    Pisano, Annalinda; Preziuso, Carmela; Iommarini, Luisa; Perli, Elena; Grazioli, Paola; Campese, Antonio F; Maresca, Alessandra; Montopoli, Monica; Masuelli, Laura; Sadun, Alfredo A; d'Amati, Giulia; Carelli, Valerio; Ghelli, Anna; Giordano, Carla

    2015-12-15

    Leber's hereditary optic neuropathy (LHON) is a maternally inherited blinding disease characterized by degeneration of retinal ganglion cells (RGCs) and consequent optic nerve atrophy. Peculiar features of LHON are incomplete penetrance and gender bias, with a marked male prevalence. Based on the different hormonal metabolism between genders, we proposed that estrogens play a protective role in females and showed that these hormones ameliorate mitochondrial dysfunction in LHON through the estrogen receptors (ERs). We also showed that ERβ localize to the mitochondria of RGCs. Thus, targeting ERβ may become a therapeutic strategy for LHON specifically aimed at avoiding or delaying the onset of disease in mutation carriers. Here, we tested the effects of ERβ targeting on LHON mitochondrial defective metabolism by treating LHON cybrid cells carrying the m.11778G>A mutation with a combination of natural estrogen-like compounds that bind ERβ with high selectivity. We demonstrated that these molecules improve cell viability by reducing apoptosis, inducing mitochondrial biogenesis and strongly reducing the levels of reactive oxygen species in LHON cells. These effects were abolished in cells with ERβ knockdown by silencing receptor expression or by using specific receptor antagonists. Our observations support the hypothesis that estrogen-like molecules may be useful in LHON prophylactic therapy. This is particularly important for lifelong disease prevention in unaffected LHON mutation carriers. Current strategies attempting to combat degeneration of RGCs during the acute phase of LHON have not been very effective. Implementing a different and preemptive approach with a low risk profile may be very helpful.

  15. Co-expressed peptide receptors in breast cancer as a molecular basis for in vivo multireceptor tumour targeting

    Energy Technology Data Exchange (ETDEWEB)

    Reubi, Jean Claude; Gugger, Mathias; Waser, Beatrice [Division of Cell Biology and Experimental Cancer Research, Institute of Pathology, University of Berne (Switzerland)

    2002-07-01

    Breast cancers can express different types of peptide receptors such as somatostatin, vasoactive intestinal peptide (VIP), gastrin-releasing peptide (GRP) and NPY(Y{sub 1}) receptors. The aim of this in vitro study was to evaluate which is the most appropriate peptide receptor or peptide receptor combination for in vivo diagnostic and therapeutic targeting of breast cancers. Seventy-seven primary breast cancers and 15 breast cancer lymph node metastases were investigated in vitro for their expression of somatostatin, VPAC{sub 1}, GRP and NPY(Y{sub 1}) receptors using in vitro receptor autoradiography on successive tissue sections with {sup 125}I-[Tyr{sup 3}]-octreotide, {sup 125}I-VIP, {sup 125}I-[Tyr{sup 4}]-bombesin and {sup 125}I-[Leu{sup 31},Pro{sup 34}]-PYY respectively. This study identified two groups of tumours: a group of 68 tumours (88%) with at least one receptor expressed at high density (>2,000 dpm/mg tissue) that may provide a strong predictive value for successful in vivo targeting, and a group of nine tumours (12%) with no receptors or only a low density of them (<2,000 dpm/mg tissue). In the group with high receptor density, 50 of the 68 tumours (74%) expressed GRP receptors, 45 (66%) expressed NPY(Y{sub 1}) receptors, 25 (37%) expressed VPAC{sub 1} receptors and 14 (21%) expressed somatostatin receptors. Mean density was 9,819{+-}530 dpm/mg tissue for GRP receptors, 9,135{+-}579 dpm/mg for NPY(Y{sub 1}) receptors, 4,337{+-}528 dpm/mg for somatostatin receptors and 3,437{+-}306 dpm/mg for VPAC{sub 1} receptors. It is of note that tumours expressing NPY(Y{sub 1}) or GRP receptors, or both, were found in 63/68 (93%) cases. Lymph node metastases showed a similar receptor profile to the corresponding primary tumour. This in vitro study strongly suggests that the combination of radiolabelled GRP and Y{sub 1} analogues should allow targeting of breast carcinomas and their lymph node metastases for in vivo peptide receptor scintigraphy and radiotherapy

  16. Targeting to 5-HT1F Receptor Subtype for Migraine Treatment

    DEFF Research Database (Denmark)

    Mitsikostas, Dimos D; Tfelt-Hansen, Peer

    2012-01-01

    The effective anti-migraine drugs triptans, all bind with high affinity to three serotonin (5-HT) subtypes, the 5-HT1B, 5-HT1D and 5-HT1F. 5- HT1B mRNA is densely localized within smooth muscle, and less in the endothelium of cerebral blood vessels. This vascular distribution of 5-HT1B receptor has...... been shown to mediate the vasoconstrictive properties of the triptans, responsible for potential cardiac adverse events. Activation of 5-HT1D subtype, although effective in animal models of migraine, was not enough efficient to attenuate migraine attacks in clinical trials. Τhe 5- HT1F receptor...... is located both in vessels and within the trigeminal ganglion (TG) and the trigeminal nucleus caudalis (Sp5C), but with the difference that the 5-HT1F receptor lack vasoconstrictive properties, making it an attractive target for new anti-migraine drugs. Selective activation of 5-HT1F receptor potently...

  17. Data on overlapping brain disorders and emerging drug targets in human Dopamine Receptors Interaction Network

    Directory of Open Access Journals (Sweden)

    Avijit Podder

    2017-06-01

    Full Text Available Intercommunication of Dopamine Receptors (DRs with their associate protein partners is crucial to maintain regular brain function in human. Majority of the brain disorders arise due to malfunctioning of such communication process. Hence, contributions of genetic factors, as well as phenotypic indications for various neurological and psychiatric disorders are often attributed as sharing in nature. In our earlier research article entitled “Human Dopamine Receptors Interaction Network (DRIN: a systems biology perspective on topology, stability and functionality of the network” (Podder et al., 2014 [1], we had depicted a holistic interaction map of human Dopamine Receptors. Given emphasis on the topological parameters, we had characterized the functionality along with the vulnerable properties of the network. In support of this, we hereby provide an additional data highlighting the genetic overlapping of various brain disorders in the network. The data indicates the sharing nature of disease genes for various neurological and psychiatric disorders in dopamine receptors connecting protein-protein interactions network. The data also indicates toward an alternative approach to prioritize proteins for overlapping brain disorders as valuable drug targets in the network.

  18. Adenosine A3 Receptor: A promising therapeutic target in cardiovascular disease.

    Science.gov (United States)

    Nishat, Shamama; Khan, Luqman A; Ansari, Zafar M; Basir, Seemi F

    2016-01-01

    Cardiovascular complications are one of the major factors for early mortality in the present worldwide scenario and have become a major challenge in both developing and developed nations. It has thus become of immense importance to look for different therapeutic possibilities and treatments for the growing burden of cardiovascular diseases. Recent advancements in research have opened various means for better understanding of the complication and treatment of the disease. Adenosine receptors have become tool of choice in understanding the signaling mechanism which might lead to the cardiovascular complications. Adenosine A3 receptor is one of the important receptor which is extensively studied as a therapeutic target in cardiovascular disorder. Recent studies have shown that A3AR is involved in the amelioration of cardiovascular complications by altering the expression of A3R. This review focuses towards the therapeutic potential of A3AR involved in cardiovascular disease and it might help in better understanding of mechanism by which this receptor may prove useful in improving the complications arising due to various cardiovascular diseases. Understanding of A3AR signaling may also help to develop newer agonists and antagonists which might be prove helpful in the treatment of cardiovascular disorder.

  19. From Smoking to Cancers: Novel Targets to Neuronal Nicotinic Acetylcholine Receptors

    Directory of Open Access Journals (Sweden)

    Chia-Hwa Lee

    2011-01-01

    Full Text Available Cigarette smoking bears a strong etiological association with many neovascularization-related diseases, including cancer, cardiovascular disease, and age-related macular degeneration. Cigarette smoke is a complex mixture of many compounds, including nicotine, which is the major active and addictive component of tobacco. Nicotine and its specific metabolized carcinogens directly bind to nicotinic acetylcholine receptors (nAChRs on cell membranes and trigger the nAChR signal cascade. The nAChRs were originally thought to be ligand-gated ion channels that modulate physiological processes ranging from neurotransmission to cancer signaling. For several decades, the nAChRs served as a prototypic molecule for neurotransmitter receptors; however, they are now important therapeutic targets for various diseases, including Alzheimer's and Parkinson's diseases, schizophrenia, and even cancer. This paper describes recent advances in our understanding of the assembly, activity, and biological functions of nicotinic receptors, as well as developments in the therapeutic application of nicotinic receptor ligands.

  20. Receptor-Tyrosine-Kinase-Targeted Therapies for Head and Neck Cancer

    Directory of Open Access Journals (Sweden)

    Lisa A. Elferink

    2011-01-01

    Full Text Available Molecular therapeutics for treating epidermal growth factor receptor-(EGFR- expressing cancers are a specific method for treating cancers compared to general cell loss with standard cytotoxic therapeutics. However, the finding that resistance to such therapy is common in clinical trials now dampens the initial enthusiasm over this targeted treatment. Yet an improved molecular understanding of other receptor tyrosine kinases known to be active in cancer has revealed a rich network of cross-talk between receptor pathways with a key finding of common downstream signaling pathways. Such cross talk may represent a key mechanism for resistance to EGFR-directed therapy. Here we review the interplay between EGFR and Met and the type 1 insulin-like growth factor receptor (IGF-1R tyrosine kinases, as well as their contribution to anti-EGFR therapeutic resistance in the context of squamous cell cancer of the head and neck, a tumor known to be primarily driven by EGFR-related oncogenic signals.

  1. Innate immune receptors in heart failure: Side effect or potential therapeutic target?

    Institute of Scientific and Technical Information of China (English)

    Katharina; B; Wagner; Stephan; B; Felix; Alexander; Riad

    2014-01-01

    Heart failure(HF) is a leading cause of mortality and morbidity in western countries and occasions major expenses for public health systems. Although optimal medical treatment is widely available according to current guidelines, the prognosis of patients with HF is still poor. Despite the etiology of the disease, increased systemic or cardiac activation of the innate immune system is well documented in several types of HF. In some cases there is evidence of an association between innate immune activation and clinical outcome of patients with this disease. However, the few large trials conducted with the use of anti-inflammatory medication in HF have not revealed its benefits. Thus, greater understanding of the relationship between alteration in the immune system and development and progression of HF is urgently necessary: prior to designing therapeutic interventions that target pathological inflammatory processes in preventing harmful cardiac effects of immune modulatory therapy. In this regard, relatively recently discovered receptors of the innate immune system, i.e., namely toll-like receptors(TLRs) and nodlike receptors(NLRs)-are the focus of intense cardiovascular research. These receptors are main up-stream regulators of cytokine activation. This review will focus on current knowledge of the role of TLRs and NLRs, as well as on downstream cytokine activation, and will discuss potential therapeutic implications.

  2. Biodegradable microspheres for the sustained release of PDGF-receptor directed PPB-HSA targeted to the fibrotic kidney

    NARCIS (Netherlands)

    Teekamp, Naomi; van Dijk, Fransien; Beljaars, Eleonora; Hinrichs, Wouter; Poelstra, Klaas; Frijlink, H.W.; Olinga, Peter

    2016-01-01

    Platelet Derived Growth Factor (PDGF) plays a key role in the development of fibrotic processes in several tissues. Accordingly, the PDGFβ receptor is abundantly present in these fibrotic tissues. Specific targeting to this receptor is established for a series of compounds in different animal models

  3. Folate receptor-targeted fluorescent paramagnetic bimodal liposomes for tumor imaging

    Directory of Open Access Journals (Sweden)

    Ding N

    2011-10-01

    Full Text Available Nan Ding1,2, Yao Lu1, Robert J Lee3, Chang Yang1, Lei Huang1, Jian Liu1, Guangya Xiang1,41School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People’s Republic of China; 2Department of Pharmacy, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People’s Republic of China; 3Division of Pharmaceutics, College of Pharmacy, The Ohio State University, Columbus, Ohio, USA; 4Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People’s Republic of China The first three authors contributed equally to this work. Rationale and objective: Receptor-targeted delivery of imaging and therapeutic agents can lead to enhanced efficacy for both. Multimodality imaging offers unique advantages over traditional single modality imaging. Tumor marker folate receptor (FR-targeted fluorescent paramagnetic bimodal liposomes were synthesized to co-deliver paramagnetic and fluorescence agents for magnetic resonance (MR and optical bimodal imaging contrast enhancement. Materials and methods: Fluorescent and paramagnetic bimodal liposomes were synthesized with a mean diameter of 136 nm and a low polydispersity index. The liposomes incorporated folate-PEG3350-CHEMS for FR targeting, Gd(III[N,N-Bis-stearylamidomethyl-N’-amidomethyl]diethylenetriamine tetraacetic acid (Gd-DTPA-BSA for MR contrast, and calcein for fluorescence. To determine the specificity and efficiency of delivery, the liposomes were evaluated in FR-positive KB and HeLa cells and FR-negative A549 cells, which were analyzed by fluorescence microscopy, magnetic resonance imaging (MRI, and flow cytometry (FCM. Results: FR-specific and efficient cellular uptake of the FR-targeted bimodal liposomes was confirmed by fluorescence microscopy and by FCM. The mean fluorescence intensity (MFI of KB cells treated with FR-targeted

  4. Role of Adenosine Receptor A2A in Traumatic Optic Neuropathies

    Science.gov (United States)

    2015-02-01

    in vivo effect of CGS21680 is important for the development of a receptor based therapy for TON. Future chal lenges include the development of...receptor agonist CGS 21680 reduces JNK MAPK activation in oligodendrocytes in injured spinal cord. Shock 32, 578–585. Gerits, N., Kostenko, S...tissues of diabetic rat. They suggested that the expression of AK to some extent is controlled by insulin . Reduced AK expression is also reported in

  5. Pregnane X receptor as a target for treatment of inflammatory bowel disorders.

    Science.gov (United States)

    Cheng, Jie; Shah, Yatrik M; Gonzalez, Frank J

    2012-06-01

    Pregnane X receptor (PXR; NR1I2), a member of the nuclear receptor superfamily, has a major role in the induction of genes involved in drug transport and metabolism. Recent studies in mice have provided insight into a novel function for PXR in inflammatory bowel disease (IBD). The mechanism of the protective effect of PXR activation on IBD is not fully established, but is due in part to the attenuation of nuclear factor (NF)-κB signaling that results in lower expression of proinflammatory cytokines. Recent clinical trials with the antibiotic rifaximin, a PXR agonist in the gastrointestinal system, have revealed its potential therapeutic value in the treatment of intestinal inflammation in humans. Thus, PXR may be a novel target for IBD therapy.

  6. From Belly to Brain: Targeting the Ghrelin Receptor in Appetite and Food Intake Regulation

    Science.gov (United States)

    Howick, Ken; Griffin, Brendan T.; Cryan, John F.; Schellekens, Harriët

    2017-01-01

    Ghrelin is the only known peripherally-derived orexigenic hormone, increasing appetite and subsequent food intake. The ghrelinergic system has therefore received considerable attention as a therapeutic target to reduce appetite in obesity as well as to stimulate food intake in conditions of anorexia, malnutrition and cachexia. As the therapeutic potential of targeting this hormone becomes clearer, it is apparent that its pleiotropic actions span both the central nervous system and peripheral organs. Despite a wealth of research, a therapeutic compound specifically targeting the ghrelin system for appetite modulation remains elusive although some promising effects on metabolic function are emerging. This is due to many factors, ranging from the complexity of the ghrelin receptor (Growth Hormone Secretagogue Receptor, GHSR-1a) internalisation and heterodimerization, to biased ligand interactions and compensatory neuroendocrine outputs. Not least is the ubiquitous expression of the GHSR-1a, which makes it impossible to modulate centrally-mediated appetite regulation without encroaching on the various peripheral functions attributable to ghrelin. It is becoming clear that ghrelin’s central signalling is critical for its effects on appetite, body weight regulation and incentive salience of food. Improving the ability of ghrelin ligands to penetrate the blood brain barrier would enhance central delivery to GHSR-1a expressing brain regions, particularly within the mesolimbic reward circuitry. PMID:28134808

  7. Targeting the androgen receptor in triple-negative breast cancer: current perspectives

    Directory of Open Access Journals (Sweden)

    Mina A

    2017-09-01

    Full Text Available Alain Mina,1 Rachel Yoder,2 Priyanka Sharma1 1Division of Medical Oncology, Department of Internal Medicine, University of Kansas Medical Center, Westwood, 2University of Kansas Cancer Center, Kansas City, KS, USA Abstract: Triple-negative breast cancer (TNBC is an aggressive subtype associated with frequent recurrence and metastasis. Unlike hormone receptor-positive subtypes, treatment of TNBC is currently limited by the lack of clinically available targeted therapies. Androgen signaling is necessary for normal breast development, and its dysregulation has been implicated in breast tumorigenesis. In recent years, gene expression studies have identified a subset of TNBC that is enriched for androgen receptor (AR signaling. Interference with androgen signaling in TNBC is promising, and AR-inhibiting drugs have shown antitumorigenic activity in preclinical and proof of concept clinical studies. Recent advances in our understanding of androgenic signaling in TNBC, along with the identification of interacting pathways, are allowing development of the next generation of clinical trials with AR inhibitors. As novel AR-targeting agents are developed and evaluated in clinical trials, it is equally important to establish a robust set of biomarkers for identification of TNBC tumors that are most likely to respond to AR inhibition. Keywords: triple-negative breast cancer, androgen signaling, targeted therapy, biomarkers, prognosis 

  8. Toll-like receptors in hepatocellular carcinoma: potential novel targets for pharmacological intervention.

    Science.gov (United States)

    Zou, Hai; Wang, Wu-Ke; Liu, Yan-Long; Braddock, Martin; Zheng, Ming-Hua; Huang, Dong-Sheng

    2016-09-01

    Toll-like receptors (TLRs) are expressed by a wide variety of cell types including immune cells. They play a crucial role in the inflammatory and host defense response against microorganisms, and triggering TLRs can mediate the activation of innate immunity. Furthermore, research suggests that various TLRs may function differently on different tumor cells. The change in TLR activity may elicit an anti-tumor activity in hepatocellular carcinoma (HCC) cells and may serve as a novel therapeutic target for HCC therapy. This review discusses the role of the TLR family in HCC and the underlying signaling pathway of TLRs as a form of pattern recognition receptor in mediating inflammation and HCC immunity responses. Agonists and antagonists of TLRs, which render TLRs as potential therapeutic targets, activate downstream molecules, subsequently causing HCC cell survival. The proliferation or protection against the development of HCC is also described. A series of studies have highlighted a crucial role of TLRs in HCC and consider TLR signaling pathways as potential therapeutic targets for HCC. However, the conclusions of these studies are in part paradoxical and controversial. Thus, it is necessary to extend further research to help determine the signaling pathways involved.

  9. From Belly to Brain: Targeting the Ghrelin Receptor in Appetite and Food Intake Regulation

    Directory of Open Access Journals (Sweden)

    Ken Howick

    2017-01-01

    Full Text Available Ghrelin is the only known peripherally-derived orexigenic hormone, increasing appetite and subsequent food intake. The ghrelinergic system has therefore received considerable attention as a therapeutic target to reduce appetite in obesity as well as to stimulate food intake in conditions of anorexia, malnutrition and cachexia. As the therapeutic potential of targeting this hormone becomes clearer, it is apparent that its pleiotropic actions span both the central nervous system and peripheral organs. Despite a wealth of research, a therapeutic compound specifically targeting the ghrelin system for appetite modulation remains elusive although some promising effects on metabolic function are emerging. This is due to many factors, ranging from the complexity of the ghrelin receptor (Growth Hormone Secretagogue Receptor, GHSR-1a internalisation and heterodimerization, to biased ligand interactions and compensatory neuroendocrine outputs. Not least is the ubiquitous expression of the GHSR-1a, which makes it impossible to modulate centrallymediated appetite regulation without encroaching on the various peripheral functions attributable to ghrelin. It is becoming clear that ghrelin’s central signalling is critical for its effects on appetite, body weight regulation and incentive salience of food. Improving the ability of ghrelin ligands to penetrate the blood brain barrier would enhance central delivery to GHSR-1a expressing brain regions, particularly within the mesolimbic reward circuitry.

  10. From Belly to Brain: Targeting the Ghrelin Receptor in Appetite and Food Intake Regulation.

    Science.gov (United States)

    Howick, Ken; Griffin, Brendan T; Cryan, John F; Schellekens, Harriët

    2017-01-27

    Ghrelin is the only known peripherally-derived orexigenic hormone, increasing appetite and subsequent food intake. The ghrelinergic system has therefore received considerable attention as a therapeutic target to reduce appetite in obesity as well as to stimulate food intake in conditions of anorexia, malnutrition and cachexia. As the therapeutic potential of targeting this hormone becomes clearer, it is apparent that its pleiotropic actions span both the central nervous system and peripheral organs. Despite a wealth of research, a therapeutic compound specifically targeting the ghrelin system for appetite modulation remains elusive although some promising effects on metabolic function are emerging. This is due to many factors, ranging from the complexity of the ghrelin receptor (Growth Hormone Secretagogue Receptor, GHSR-1a) internalisation and heterodimerization, to biased ligand interactions and compensatory neuroendocrine outputs. Not least is the ubiquitous expression of the GHSR-1a, which makes it impossible to modulate centrallymediated appetite regulation without encroaching on the various peripheral functions attributable to ghrelin. It is becoming clear that ghrelin's central signalling is critical for its effects on appetite, body weight regulation and incentive salience of food. Improving the ability of ghrelin ligands to penetrate the blood brain barrier would enhance central delivery to GHSR-1a expressing brain regions, particularly within the mesolimbic reward circuitry.

  11. Stabilization of HIV-1 gp120-CD4 Receptor Complex through Targeted Interchain Disulfide Exchange*

    Science.gov (United States)

    Cerutti, Nichole; Mendelow, Barry V.; Napier, Grant B.; Papathanasopoulos, Maria A.; Killick, Mark; Khati, Makobetsa; Stevens, Wendy; Capovilla, Alexio

    2010-01-01

    HIV-1 enters cells via interaction between the trimeric envelope (Env) glycoprotein gp120/gp41 and the host cell surface receptor molecule CD4. The requirement of CD4 for viral entry has rationalized the development of recombinant CD4-based proteins as competitive viral attachment inhibitors and immunotherapeutic agents. In this study, we describe a novel recombinant CD4 protein designed to bind gp120 through a targeted disulfide-exchange mechanism. According to structural models of the gp120-CD4 receptor complex, substitution of Ser60 on the CD4 domain 1 α-helix with Cys positions a thiol in proximity of the gp120 V1/V2 loop disulfide (Cys126–Cys196), satisfying the stereochemical and geometric conditions for redox exchange between CD4 Cys60 and gp120 Cys126, and the consequent formation of an interchain disulfide bond. In this study, we provide experimental evidence for this effect by describing the expression, purification, refolding, receptor binding and antiviral activity analysis of a recombinant two-domain CD4 variant containing the S60C mutation (2dCD4-S60C). We show that 2dCD4-S60C binds HIV-1 gp120 with a significantly higher affinity than wild-type protein under conditions that facilitate disulfide exchange and that this translates into a corresponding increase in the efficacy of CD4-mediated viral entry inhibition. We propose that targeted redox exchange between conserved gp120 disulfides and nucleophilic moieties positioned strategically on CD4 (or CD4-like scaffolds) conceptualizes a new strategy in the development of high affinity HIV-1 Env ligands, with important implications for therapy and vaccine development. More generally, this chalcogen substitution approach provides a general means of stabilizing receptor-ligand complexes where the structural and biophysical conditions for disulfide exchange are satisfied. PMID:20538591

  12. Stabilization of HIV-1 gp120-CD4 receptor complex through targeted interchain disulfide exchange.

    Science.gov (United States)

    Cerutti, Nichole; Mendelow, Barry V; Napier, Grant B; Papathanasopoulos, Maria A; Killick, Mark; Khati, Makobetsa; Stevens, Wendy; Capovilla, Alexio

    2010-08-13

    HIV-1 enters cells via interaction between the trimeric envelope (Env) glycoprotein gp120/gp41 and the host cell surface receptor molecule CD4. The requirement of CD4 for viral entry has rationalized the development of recombinant CD4-based proteins as competitive viral attachment inhibitors and immunotherapeutic agents. In this study, we describe a novel recombinant CD4 protein designed to bind gp120 through a targeted disulfide-exchange mechanism. According to structural models of the gp120-CD4 receptor complex, substitution of Ser(60) on the CD4 domain 1 alpha-helix with Cys positions a thiol in proximity of the gp120 V1/V2 loop disulfide (Cys(126)-Cys(196)), satisfying the stereochemical and geometric conditions for redox exchange between CD4 Cys(60) and gp120 Cys(126), and the consequent formation of an interchain disulfide bond. In this study, we provide experimental evidence for this effect by describing the expression, purification, refolding, receptor binding and antiviral activity analysis of a recombinant two-domain CD4 variant containing the S60C mutation (2dCD4-S60C). We show that 2dCD4-S60C binds HIV-1 gp120 with a significantly higher affinity than wild-type protein under conditions that facilitate disulfide exchange and that this translates into a corresponding increase in the efficacy of CD4-mediated viral entry inhibition. We propose that targeted redox exchange between conserved gp120 disulfides and nucleophilic moieties positioned strategically on CD4 (or CD4-like scaffolds) conceptualizes a new strategy in the development of high affinity HIV-1 Env ligands, with important implications for therapy and vaccine development. More generally, this chalcogen substitution approach provides a general means of stabilizing receptor-ligand complexes where the structural and biophysical conditions for disulfide exchange are satisfied.

  13. Selective autophagy of non-ubiquitylated targets in plants: looking for cognate receptor/adaptor proteins

    Directory of Open Access Journals (Sweden)

    Vasko eVeljanovski

    2014-06-01

    Full Text Available Cellular homeostasis is essential for the physiology of eukaryotic cells. Eukaryotic cells, including plant cells, utilize two main pathways to adjust the level of cytoplasmic components, namely the proteasomal and the lysosomal/vacuolar pathways. Macroautophagy is a lysosomal/vacuolar pathway which, until recently, was thought to be non-specific and a bulk degradation process. However, selective autophagy which can be activated in the cell under various physiological conditions, involves the specific degradation of defined macromolecules or organelles by a conserved molecular mechanism. For this process to be efficient, the mechanisms underlying the recognition and selection of the cargo to be engulfed by the double-membrane autophagosome are critical, and not yet well understood. Ubiquitin (poly-ubiquitin conjugation to the target appears to be a conserved ligand mechanism in many types of selective autophagy, and defined receptors/adaptors recognizing and regulating the autophagosomal capture of the ubiquitylated target have been characterized. However, non-proteinaceous and non-ubiquitylated cargoes are also selectively degraded by this pathway. This ubiquitin-independent selective autophagic pathway also involves receptor and/or adaptor proteins linking the cargo to the autophagic machinery. Some of these receptor/adaptor proteins including accessory autophagy-related (Atg and non-Atg proteins have been described in yeast and animal cells but not yet in plants. In this review we discuss the ubiquitin-independent cargo selection mechanisms in selective autophagy degradation of organelles and macromolecules and speculate on potential plant receptor/adaptor proteins.

  14. Presynaptic facilitatory adenosine A2A receptors mediate fade induced by neuromuscular relaxants that exhibit anticholinesterase activity.

    Science.gov (United States)

    Bornia, Elaine Cs; Correia-de-Sá, Paulo; Alves-Do-Prado, Wilson

    2011-03-01

    1. Pancuronium, cisatracurium and vecuronium are antinicotinic agents that, in contrast with d-tubocurarine and hexamethonium, exhibit anticholinesterase activity. Pancuronium-, cisatracurium- and vecuronium-induced fade results from blockade of facilitatory nicotinic receptors on motor nerves, but fade produced by such agents also depends on the presynaptic activation of inhibitory muscarinic M2 receptors by acetylcholine released from motor nerve terminals and activation of inhibitory adenosine A1 receptors by adenosine released from motor nerves and muscles. The participation of presynaptic facilitatory A2A receptors in fade caused by pancuronium, cisatracurium and vecuronium has not yet been investigated. In the present study, we determined the effects of ZM241385, an antagonist of presynaptic facilitatory A2A receptors, on fade produced by these neuromuscular relaxants in the rat phrenic nerve-diaphragm (PND) preparation. 2. The muscles were stimulated indirectly at 75±3Hz to induce a sustained tetanizing muscular contraction. The lowest concentration at which each antinicotinic agent produced fade without modifying initial tetanic tension (presynaptic action) was determined. 3. d-Tubocurarine-induced fade occurred only at 55 nmol/L, a concentration that also reduced maximal tetanic tension (post-synaptic action). At 10 nmol/L, ZM 241385 alone did not produce fade, but it did attenuate pancuronium (0.32 μmol/L)-, cisatracurium (0.32 μmol/L)- and vecuronium (0.36 μmol/L)-induced fade. 4. The fade induced by the 'pure' antinicotinic agents d-tubocurarine (55 nmol/L) and hexamethonium (413 μmol/L) was not altered by 10 nmol/L ZM 241385, indicating that presynaptic adenosine A2A receptors play a significant role in the fade produced by antinicotinic agents when such agents have anticholinesterase activity.

  15. Sleeping Beauty Transposition of Chimeric Antigen Receptors Targeting Receptor Tyrosine Kinase-Like Orphan Receptor-1 (ROR1) into Diverse Memory T-Cell Populations

    Science.gov (United States)

    Deniger, Drew C.; Yu, Jianqiang; Huls, M. Helen; Figliola, Matthew J.; Mi, Tiejuan; Maiti, Sourindra N.; Widhopf, George F.; Hurton, Lenka V.; Thokala, Radhika; Singh, Harjeet; Olivares, Simon; Champlin, Richard E.; Wierda, William G.; Kipps, Thomas J.; Cooper, Laurence J. N.

    2015-01-01

    T cells modified with chimeric antigen receptors (CARs) targeting CD19 demonstrated clinical activity against some B-cell malignancies. However, this is often accompanied by a loss of normal CD19+ B cells and humoral immunity. Receptor tyrosine kinase-like orphan receptor-1 (ROR1) is expressed on sub-populations of B-cell malignancies and solid tumors, but not by healthy B cells or normal post-partum tissues. Thus, adoptive transfer of T cells specific for ROR1 has potential to eliminate tumor cells and spare healthy tissues. To test this hypothesis, we developed CARs targeting ROR1 in order to generate T cells specific for malignant cells. Two Sleeping Beauty transposons were constructed with 2nd generation ROR1-specific CARs signaling through CD3ζ and either CD28 (designated ROR1RCD28) or CD137 (designated ROR1RCD137) and were introduced into T cells. We selected for T cells expressing CAR through co-culture with γ-irradiated activating and propagating cells (AaPC), which co-expressed ROR1 and co-stimulatory molecules. Numeric expansion over one month of co-culture on AaPC in presence of soluble interleukin (IL)-2 and IL-21 occurred and resulted in a diverse memory phenotype of CAR+ T cells as measured by non-enzymatic digital array (NanoString) and multi-panel flow cytometry. Such T cells produced interferon-γ and had specific cytotoxic activity against ROR1+ tumors. Moreover, such cells could eliminate ROR1+ tumor xenografts, especially T cells expressing ROR1RCD137. Clinical trials will investigate the ability of ROR1-specific CAR+ T cells to specifically eliminate tumor cells while maintaining normal B-cell repertoire. PMID:26030772

  16. Sleeping Beauty Transposition of Chimeric Antigen Receptors Targeting Receptor Tyrosine Kinase-Like Orphan Receptor-1 (ROR1 into Diverse Memory T-Cell Populations.

    Directory of Open Access Journals (Sweden)

    Drew C Deniger

    Full Text Available T cells modified with chimeric antigen receptors (CARs targeting CD19 demonstrated clinical activity against some B-cell malignancies. However, this is often accompanied by a loss of normal CD19+ B cells and humoral immunity. Receptor tyrosine kinase-like orphan receptor-1 (ROR1 is expressed on sub-populations of B-cell malignancies and solid tumors, but not by healthy B cells or normal post-partum tissues. Thus, adoptive transfer of T cells specific for ROR1 has potential to eliminate tumor cells and spare healthy tissues. To test this hypothesis, we developed CARs targeting ROR1 in order to generate T cells specific for malignant cells. Two Sleeping Beauty transposons were constructed with 2nd generation ROR1-specific CARs signaling through CD3ζ and either CD28 (designated ROR1RCD28 or CD137 (designated ROR1RCD137 and were introduced into T cells. We selected for T cells expressing CAR through co-culture with γ-irradiated activating and propagating cells (AaPC, which co-expressed ROR1 and co-stimulatory molecules. Numeric expansion over one month of co-culture on AaPC in presence of soluble interleukin (IL-2 and IL-21 occurred and resulted in a diverse memory phenotype of CAR+ T cells as measured by non-enzymatic digital array (NanoString and multi-panel flow cytometry. Such T cells produced interferon-γ and had specific cytotoxic activity against ROR1+ tumors. Moreover, such cells could eliminate ROR1+ tumor xenografts, especially T cells expressing ROR1RCD137. Clinical trials will investigate the ability of ROR1-specific CAR+ T cells to specifically eliminate tumor cells while maintaining normal B-cell repertoire.

  17. Involvement of 5-HT(2A/2B/2C) receptors on memory formation: simple agonism, antagonism, or inverse agonism?

    Science.gov (United States)

    Meneses, Alfredo

    2002-12-01

    1. The 5-HT2 receptors subdivision into the 5-HT(2A/2B/2C) subtypes along with the advent of the selective antagonists has allowed a more detailed investigation on the role and therapeutic significance of these subtypes in cognitive functions. The present study further analyzed the 5-HT2 receptors role on memory consolidation. 2. The SB-200646 (a selective 5-HT(2B/2C) receptor antagonist) and LY215840 (a nonselective 5-HT(2/7) receptor antagonist) posttraining administration had no effect on an autoshaped memory consolidation. However, both drugs significantly and differentially antagonized the memory impairments induced by 1-(3-chlorophenyl)piperazine (mCPP), 1-naphtyl-piperazine (1-NP), mesulergine, or N-(3-trifluoromethylphenyl) piperazine (TFMPP). 3. In contrast, SB-200646 failed to modify the facilitatory procognitive effect produced by (+/-)-2.5-dimethoxy-4-iodoamphetamine (DOI) or ketanserin, which were sensitive to MDL100907 (a selective 5-HT2A receptor antagonist) and to a LY215840 high dose. 4. Finally, SB-200646 reversed the learning deficit induced by dizocilpine, but not that by scopolamine: while SB-200646 and MDL100907 coadministration reversed memory deficits induced by both drugs. 5. It is suggested that 5-HT(2B/2C) receptors might be involved on memory formation probably mediating a suppressive or constraining action. Whether the drug-induced memory impairments in this study are explained by simple agonism, antagonism, or inverse agonism at 5-HT2 receptors remains unclear at this time. 6. Notably, the 5-HT2 receptor subtypes blockade may provide some benefit to reverse poor memory consolidation conditions associated with decreasedcholinergic, glutamatergic, and/or serotonergic neurotransmission.

  18. Identification of the immunodominant epitope region in phospholipase A2 receptor-mediating autoantibody binding in idiopathic membranous nephropathy.

    Science.gov (United States)

    Kao, Liyo; Lam, Vinson; Waldman, Meryl; Glassock, Richard J; Zhu, Quansheng

    2015-02-01

    Membranous nephropathy (MN) is a common cause of nephrotic syndrome in adults. Recent clinical studies established that >70% of patients with idiopathic (also called primary) MN (IMN) possess circulating autoantibodies targeting the M-type phospholipase A2 receptor-1 (PLA2R) on the surface of glomerular visceral epithelial cells (podocytes). In situ, these autoantibodies trigger the formation of immune complexes, which are hypothesized to cause enhanced glomerular permeability to plasma proteins. Indeed, the level of autoantibody in circulation correlates with the severity of proteinuria in patients. The autoantibody only recognizes the nonreduced form of PLA2R, suggesting that disulfide bonds determine the antigenic epitope conformation. Here, we identified the immunodominant epitope region in PLA2R by probing isolated truncated PLA2R extracellular domains with sera from patients with IMN that contain anti-PLA2R autoantibodies. Patient sera specifically recognized a protein complex consisting of the cysteine-rich (CysR), fibronectin-like type II (FnII), and C-type lectin-like domain 1 (CTLD1) domains of PLA2R only under nonreducing conditions. Moreover, absence of either the CysR or CTLD1 domain prevented autoantibody recognition of the remaining domains. Additional analysis suggested that this three-domain complex contains at least one disulfide bond required for conformational configuration and autoantibody binding. Notably, the three-domain complex completely blocked the reactivity of autoantibodies from patient sera with the full-length PLA2R, and the reactivity of patient sera with the three-domain complex on immunoblots equaled the reactivity with full-length PLA2R. These results indicate that the immunodominant epitope in PLA2R is exclusively located in the CysR-FnII-CTLD1 region.

  19. In vivo evaluation of [11C]preladenant positron emission tomography for quantification of adenosine A2A receptors in the rat brain

    NARCIS (Netherlands)

    Zhou, Xiaoyun; Khanapur, Shivashankar; de Jong, Johan R; Willemsen, Antoon T.M.; Dierckx, Rudi Ajo; Elsinga, Philip H; de Vries, Erik Fj

    2016-01-01

    [(11)C]Preladenant was developed as a novel adenosine A2A receptor positron emission tomography radioligand. The present study aims to evaluate the suitability of [(11)C]preladenant positron emission tomography for the quantification of striatal A2A receptor density and the assessment of striatal A2

  20. Enthalpy-Entropy Compensation in the Binding of Modulators at Ionotropic Glutamate Receptor GluA2

    DEFF Research Database (Denmark)

    Krintel, Christian; Francotte, Pierre; Pickering, Darryl S

    2016-01-01

    The 1,2,4-benzothiadiazine 1,1-dioxide type of positive allosteric modulators of the ionotropic glutamate receptor A2 (GluA2) are promising lead compounds for the treatment of cognitive disorders, e.g., Alzheimer’s disease. The modulators bind in a cleft formed by the interface of two neighboring.......5 (4) and 4.8 (5). Thus, the dissociation constants (Kd, μM) of 4 (11.2) and 5 (0.16) are similar to those of 2 (5.6) and 3 (0.35). Functionally, 4 and 5 potentiated responses of 10 μM L-glutamate at homomeric rat GluA2(Q)i receptors with EC50 values of 67.3 and 2.45 μM, respectively. The binding mode...

  1. Bitter taste receptors as targets for tocolytics in preterm labor therapy.

    Science.gov (United States)

    Zheng, Kaizhi; Lu, Ping; Delpapa, Ellen; Bellve, Karl; Deng, Ruitang; Condon, Jennifer C; Fogarty, Kevin; Lifshitz, Lawrence M; Simas, Tiffany A Moore; Shi, Fangxiong; ZhuGe, Ronghua

    2017-09-01

    Preterm birth (PTB) is the leading cause of neonatal mortality and morbidity, with few prevention and treatment options. Uterine contraction is a central feature of PTB, so gaining new insights into the mechanisms of this contraction and consequently identifying novel targets for tocolytics are essential for more successful management of PTB. Here we report that myometrial cells from human and mouse express bitter taste receptors (TAS2Rs) and their canonical signaling components (i.e., G-protein gustducin and phospholipase C β2). Bitter tastants can completely relax myometrium precontracted by different uterotonics. In isolated single mouse myometrial cells, a phenotypical bitter tastant (chloroquine, ChQ) reverses the rise in intracellular Ca(2+) concentration ([Ca(2+)]i) and cell shortening induced by uterotonics, and this reversal effect is inhibited by pertussis toxin and by genetic deletion of α-gustducin. In human myometrial cells, knockdown of TAS2R14 but not TAS2R10 inhibits ChQ's reversal effect on an oxytocin-induced rise in [Ca(2+)]i Finally, ChQ prevents mouse PTBs induced by bacterial endotoxin LPS or progesterone receptor antagonist mifepristone more often than current commonly used tocolytics, and this prevention is largely lost in α-gustducin-knockout mice. Collectively, our results reveal that activation of the canonical TAS2R signaling system in myometrial cells produces profound relaxation of myometrium precontracted by a broad spectrum of contractile agonists, and that targeting TAS2Rs is an attractive approach to developing effective tocolytics for PTB management.-Zheng, K., Lu, P., Delpapa, E., Bellve, K., Deng, R., Condon, J. C., Fogarty, K., Lifshitz, L. M., Simas, T. A. M., Shi, F., ZhuGe, R. Bitter taste receptors as targets for tocolytics in preterm labor therapy. © FASEB.

  2. Galactosylated manganese ferrite nanoparticles for targeted MR imaging of asialoglycoprotein receptor.

    Science.gov (United States)

    Yang, Seung-Hyun; Heo, Dan; Lee, Eugene; Kim, Eunjung; Lim, Eun-Kyung; Lee, Young Han; Haam, Seungjoo; Suh, Jin-Suck; Huh, Yong-Min; Yang, Jaemoon; Park, Sahng Wook

    2013-11-29

    Cancer cells can express specific biomarkers, such as cell membrane proteins and signaling factors. Thus, finding biomarkers and delivering diagnostic agents are important in the diagnosis of cancer. In this study, we investigated a biomarker imaging agent for the diagnosis of hepatic cancers. The asialoglycoprotein receptor (ASGPr) was selected as a biomarker for hepatoma cells and the ASGPr-targetable imaging agent bearing a galactosyl group was prepared using manganese ferrite nanoparticles (MFNP) and galactosylgluconic acid. The utility of the ASGPr-targetable imaging agent, galactosylated MFNP (G-MFNP) was assessed by several methods in ASGPr-expressing HepG2 cells as target cells and ASGPr-deficient MCF7 cells. Physical and chemical properties of G-MFNP were examined using Fourier-transform infrared spectroscopy, dynamic light scattering, zeta potential analysis, and transmission electron microscopy. No significant cytotoxicity was observed in either cell line. Targeting ability was assessed using flow cytometry, magnetic resonance imaging, inductively coupled plasma atomic emission spectroscopy, absorbance analysis, dark-field microscopy, Prussian blue staining, and transmission electron microscopy. We demonstrated that G-MFNP target successfully and bind to ASGPr-expressing HepG2 cells specifically. We suggest that these results will be useful in strategies for cancer diagnoses based on magnetic resonance imaging.

  3. Small-Molecule Inhibitors of the Receptor Tyrosine Kinases: Promising Tools for Targeted Cancer Therapies

    Directory of Open Access Journals (Sweden)

    Mohammad Hojjat-Farsangi

    2014-08-01

    Full Text Available Chemotherapeutic and cytotoxic drugs are widely used in the treatment of cancer. In spite of the improvements in the life quality of patients, their effectiveness is compromised by several disadvantages. This represents a demand for developing new effective strategies with focusing on tumor cells and minimum side effects. Targeted cancer therapies and personalized medicine have been defined as a new type of emerging treatments. Small molecule inhibitors (SMIs are among the most effective drugs for targeted cancer therapy. The growing number of approved SMIs of receptor tyrosine kinases (RTKs i.e., tyrosine kinase inhibitors (TKIs in the clinical oncology imply the increasing attention and application of these therapeutic tools. Most of the current approved RTK–TKIs in preclinical and clinical settings are multi-targeted inhibitors with several side effects. Only a few specific/selective RTK–TKIs have been developed for the treatment of cancer patients. Specific/selective RTK–TKIs have shown less deleterious effects compared to multi-targeted inhibitors. This review intends to highlight the importance of specific/selective TKIs for future development with less side effects and more manageable agents. This article provides an overview of: (1 the characteristics and function of RTKs and TKIs; (2 the recent advances in the improvement of specific/selective RTK–TKIs in preclinical or clinical settings; and (3 emerging RTKs for targeted cancer therapies by TKIs.

  4. Complement receptor 2-mediated targeting of complement inhibitors to sites of complement activation.

    Science.gov (United States)

    Song, Hongbin; He, Chun; Knaak, Christian; Guthridge, Joel M; Holers, V Michael; Tomlinson, Stephen

    2003-06-01

    In a strategy to specifically target complement inhibitors to sites of complement activation and disease, recombinant fusion proteins consisting of a complement inhibitor linked to a C3 binding region of complement receptor (CR) 2 were prepared and characterized. Natural ligands for CR2 are C3 breakdown products deposited at sites of complement activation. Fusion proteins were prepared consisting of a human CR2 fragment linked to either the N terminus or C terminus of soluble forms of the membrane complement inhibitors decay accelerating factor (DAF) or CD59. The targeted complement inhibitors bound to C3-opsonized cells, and all were significantly more effective (up to 20-fold) than corresponding untargeted inhibitors at protecting target cells from complement. CR2 fusion proteins also inhibited CR3-dependent adhesion of U937 cells to C3 opsonized erythrocytes, indicating a second potential anti-inflammatory mechanism of CR2 fusion proteins, since CR3 is involved in endothelial adhesion and diapedesis of leukocytes at inflammatory sites. Finally, the in vivo validity of the targeting strategy was confirmed by the demonstration that CR2-DAF, but not soluble DAF, targets to the kidney in mouse models of lupus nephritis that are associated with renal complement deposition.

  5. Transepithelial Transport of Fc -Targeted Nanoparticles by the Neonatal Fc Receptor for Oral Delivery

    Science.gov (United States)

    Pridgen, Eric M.; Alexis, Frank; Kuo, Timothy T.; Levy-Nissenbaum, Etgar; Karnik, Rohit; Blumberg, Richard S.; Langer, Robert; Farokhzad, Omid C.

    2014-01-01

    Nanoparticles are poised to have a tremendous impact on the treatment of many diseases, but their broad application is limited because currently they can only be administered by parenteral methods. Oral administration of nanoparticles is preferred but remains a challenge because transport across the intestinal epithelium is limited. Here, we show that nanoparticles targeted to the neonatal Fc receptor (FcRn), which is known to mediate the transport of IgG antibodies across epithelial barriers, are efficiently transported across the intestinal epithelium using both in vitro and in vivo models. In mice, orally administered FcRn-targeted nanoparticles crossed the intestinal epithelium and reached systemic circulation with a mean absorption efficiency of 13.7%*h compared with only 1.2%*h for non-targeted nanoparticles. In addition, targeted nanoparticles containing insulin as a model nanoparticle-based therapy for diabetes were orally administered at a clinically relevant insulin dose of 1.1 U/kg and elicited a prolonged hypoglycemic response in wild-type mice. This effect was abolished in FcRn knockout mice, indicating the enhanced nanoparticle transport was due specifically to FcRn. FcRn-targeted nanoparticles may have a major impact on the treatment of many diseases by enabling drugs currently limited by low bioavailability to be efficiently delivered though oral administration. PMID:24285486

  6. Redox-regulated cargo binding and release by the peroxisomal targeting signal receptor, Pex5.

    Science.gov (United States)

    Ma, Changle; Hagstrom, Danielle; Polley, Soumi Guha; Subramani, Suresh

    2013-09-20

    In its role as a mobile receptor for peroxisomal matrix cargo containing a peroxisomal targeting signal called PTS1, the protein Pex5 shuttles between the cytosol and the peroxisome lumen. Pex5 binds PTS1 proteins in the cytosol via its C-terminal tetratricopeptide domains and delivers them to the peroxisome lumen, where the receptor·cargo complex dissociates. The cargo-free receptor is exported to the cytosol for another round of import. How cargo release and receptor recycling are regulated is poorly understood. We found that Pex5 functions as a dimer/oligomer and that its protein interactions with itself (homo-oligomeric) and with Pex8 (hetero-oligomeric) control the binding and release of cargo proteins. These interactions are controlled by a redox-sensitive amino acid, cysteine 10 of Pex5, which is essential for the formation of disulfide bond-linked Pex5 forms, for high affinity cargo binding, and for receptor recycling. Disulfide bond-linked Pex5 showed the highest affinity for PTS1 cargo. Upon reduction of the disulfide bond by dithiothreitol, Pex5 transitioned to a noncovalent dimer, concomitant with the partial release of PTS1 cargo. Additionally, dissipation of the redox balance between the cytosol and the peroxisome lumen caused an import defect. A hetero-oligomeric interaction between the N-terminal domain (amino acids 1-110) of Pex5 and a conserved motif at the C terminus of Pex8 further facilitates cargo release, but only under reducing conditions. This interaction is also important for the release of PTS1 proteins. We suggest a redox-regulated model for Pex5 function during the peroxisomal matrix protein import cycle.

  7. DDR2 (discoidin domain receptor 2) suppresses osteoclastogenesis and is a potential therapeutic target in osteoporosis.

    Science.gov (United States)

    Zhang, Yan; Su, Jin; Wu, Shufang; Teng, Yue; Yin, Zhanhai; Guo, Yan; Li, Jing; Li, Kun; Yao, Libo; Li, Xu

    2015-03-24

    Osteoporosis is a disease characterized by abnormal skeletal fragility due to an imbalance in bone homeostasis. Finding therapeutic targets that promote bone formation is valuable for treating osteoporosis. Discoidin domain receptor 2 (DDR2) is a receptor tyrosine kinase that promotes the differentiation of bone-depositing cells, osteoblasts, and bone formation. We investigated the role of DDR2 in osteoclastogenesis, the formation of cells responsible for bone resorption. We found that, although differentiated osteoclasts had catalytically active DDR2, its abundance was decreased. Overexpression of DDR2 inhibited the expression of osteoclastic markers, osteoclast maturation, and osteoclast-mediated bone resorption in a culture model of bone matrix. Conversely, knocking down Ddr2 through RNA interference accelerated osteoclast differentiation and bone resorption in mice. Further, we identified the co-receptor Neuropilin-1 (Nrp1) as a DDR2-interacting protein. DDR2 facilitated the binding of Nrp1 and the co-receptor PlexinA1 by forming a DDR2-Nrp1-PlexinA1 complex, which blocked PlexinA1-mediated stimulation of osteoclastogenesis. DDR2 prevented PlexinA1 from interacting with the receptor TREM2 and the adaptor DAP12. Moreover, knocking down Nrp1 rescued the expression of osteoclastic markers observed in DDR2-overexpressing cells, whereas ectopic expression of Nrp1 in DDR2-silenced cells inhibited the induction of osteoclastogenesis. Nrp1 enhanced the function of DDR2 in promoting osteoblast differentiation and bone formation in mice. In an ovariectomized mouse model of osteoporosis, adenovirus-mediated delivery of DDR2 to the femur bone alleviated osteopenic phenotypes. Our results revealed that DDR2 functions as an inhibitor of osteoclastogenesis, as well as a promoter of osteoblastogenesis, suggesting that enhancing DDR2 may be therapeutic for patients with osteoporosis.

  8. Autoantibodies against phospholipase A2 receptor in Korean patients with membranous nephropathy.

    Directory of Open Access Journals (Sweden)

    Yun Jung Oh

    Full Text Available The data were presented in abstract form at the 45(th meeting of the American Society of Nephrology, October 30-November 04 2012, San Diego, CA, USA. Circulating autoantibodies against M-type phospholipase A2 receptor (PLA2R are important pathogenic antibodies of idiopathic membranous nephropathy (MN in adults. However, previous studies on the clinical impact of anti-PLA2R antibodies demonstrated several limitations, including insufficient numbers of study subjects and different time points and methods for anti-PLA2R antibody measurement. To verify the clinical significance of anti-PLA2R antibodies in Korean patients with MN, we measured autoantibodies in serum samples obtained at the time of biopsy from a total of 100 patients with idiopathic MN who had not yet received immunosuppressive treatment. We detected anti-PLA2R antibody in 69 patients, and we observed that autoantibody reactivity reflected the severity of disease activity. Proteinuria and hypoalbuminemia were more severe in patients with anti-PLA2R than in those without the autoantibodies (2.95 g/g vs. 6.85 g/g, P = 0.003; 3.1 g/dL vs. 2.5 g/dL, P = 0.004, respectively. Additionally, the clinical severities worsened proportionally as the levels of anti-PLA2R antibodies increased (P = 0.015 and P for trend <0.001 for proteinuria and hypoalbuminemia, respectively. However, neither the levels nor the presence or absence of anti-PLA2R antibody showed a significant correlation with clinical outcomes, such as remission rate and time to remission. In conclusion, we observed that anti-PLA2R antibodies are highly prevalent in Korean patients with idiopathic MN and that they reflect the clinical disease activity before the administration of immunosuppressive treatment. However, the levels of anti-PLA2R antibody at the time of kidney biopsy may not predict the clinical outcomes in current clinical practice.

  9. Striatal adenosine A2A and cannabinoid CB1 receptors form functional heteromeric complexes that mediate the motor effects of cannabinoids.

    Science.gov (United States)

    Carriba, Paulina; Ortiz, Oskar; Patkar, Kshitij; Justinova, Zuzana; Stroik, Jessica; Themann, Andrea; Müller, Christa; Woods, Anima S; Hope, Bruce T; Ciruela, Francisco; Casadó, Vicent; Canela, Enric I; Lluis, Carme; Goldberg, Steven R; Moratalla, Rosario; Franco, Rafael; Ferré, Sergi

    2007-11-01

    The mechanism of action responsible for the motor depressant effects of cannabinoids, which operate through centrally expressed cannabinoid CB1 receptors, is still a matter of debate. In the present study, we report that CB1 and adenosine A2A receptors form heteromeric complexes in co-transfected HEK-293T cells and rat striatum, where they colocalize in fibrilar structures. In a human neuroblastoma cell line, CB1 receptor signaling was found to be completely dependent on A2A receptor activation. Accordingly, blockade of A2A receptors counteracted the motor depressant effects produced by the intrastriatal administration of a cannabinoid CB1 receptor agonist. These biochemical and behavioral findings demonstrate that the profound motor effects of cannabinoids depend on physical and functional interactions between striatal A2A and CB1 receptors.

  10. Neuronal nicotinic receptors as novel targets for inflammation and neuroprotection:mechanistic considerations and clinical relevance

    Institute of Scientific and Technical Information of China (English)

    Merouane BENGHEKIF

    2009-01-01

    A number of studies have confirmed the potential for neuronal nicotinic acetylcholine receptor (NNR)-mediated neuro- protection and, more recently, its anti-inflammatory effects. The mechanistic overlap between these pathways and the ubiquitous effects observed following diverse insults suggest that NNRs modulate fundamental pathways involved in cell survival. These results have wide-reaching implications for the design of experimental therapeutics that regulate inflamma- tory and anti-apoptotic responses through NNRs and represent an initial step toward understanding the benefits of novel therapeutic strategies for the management of central nervous system disorders that target neuronal survival and associated inflammatory processes.

  11. Targeting of the P2X7 receptor in pancreatic cancer and stellate cells.

    OpenAIRE

    Giannuzzo, Andrea; Saccomano, Mara; Napp, Joanna; Ellegaard, Maria; Alves, Frauke; Novak, Ivana

    2016-01-01

    The ATP-gated receptor P2X7 (P2X7R) is involved in regulation of cell survival and has been of interest in cancer field. Pancreatic ductal adenocarcinoma (PDAC) is a deadly cancer and new markers and therapeutic targets are needed. PDAC is characterized by a complex tumour microenvironment, which includes cancer and pancreatic stellate cells (PSCs), and potentially high nucleotide/side turnover. Our aim was to determine P2X7R expression and function in human pancreatic cancer cells in vitro a...

  12. Comparative study of radiation emission without and with target in a 2.2 kJ plasma focus device

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Muhammad Zubair, E-mail: mzubairkhan-um76@yahoo.com [Plasma Technology Research Center, Department of Physics, Faculty of Science, University Malaya, 50603 Kuala Lumpur Malaysia and Department of Physics, Federal Urdu University of Arts, Science and Technology, 45320 Islamabad (Pakistan); Ling, Yap Seong; San, Wong Chiow [Plasma Technology Research Center, Department of Physics, Faculty of Science, University Malaya, 50603 Kuala Lumpur (Malaysia)

    2014-03-24

    The radiation emission in a 2.2 kJ Mather-type dense plasma focus device is investigated using a five channel BPX65 PIN diode spectrometer. Estimated X-ray associated with the hollow anode without and with target in Argon gas medium is compared. At optimum conditions, the radiation emission from the system is found to be strongly influenced with target in hollow anode and the filling gas pressure. The maximum X-ray yield in 4π sr was obtained in case of hollow anode in argon gas medium with target 'Lead' due to interaction of electron beam. Results indicated that an appropriate design of hollow anode with target could enhance the radiation emission by more intense interaction of expected electron beam with target. The outcomes are helpful in designing a plasma focus with enhanced X-ray radiation with improved shot to shot reproducibility in plasma focus device.

  13. Adenosine A(2A receptors measured with [C]TMSX PET in the striata of Parkinson's disease patients.

    Directory of Open Access Journals (Sweden)

    Masahiro Mishina

    Full Text Available Adenosine A(2A receptors (A2ARs are thought to interact negatively with the dopamine D(2 receptor (D2R, so selective A2AR antagonists have attracted attention as novel treatments for Parkinson's disease (PD. However, no information about the receptor in living patients with PD is available. The purpose of this study was to investigate the relationship between A2ARs and the dopaminergic system in the striata of drug-naïve PD patients and PD patients with dyskinesia, and alteration of these receptors after antiparkinsonian therapy. We measured binding ability of striatal A2ARs using positron emission tomography (PET with [7-methyl-(11C]-(E-8-(3,4,5-trimethoxystyryl-1,3,7-trimethylxanthine ([(11C]TMSX in nine drug-naïve patients with PD, seven PD patients with mild dyskinesia and six elderly control subjects using PET. The patients and eight normal control subjects were also examined for binding ability of dopamine transporters and D2Rs. Seven of the drug-naïve patients underwent a second series of PET scans following therapy. We found that the distribution volume ratio of A2ARs in the putamen were larger in the dyskinesic patients than in the control subjects (p<0.05, Tukey-Kramer post hoc test. In the drug-naïve patients, the binding ability of the A2ARs in the putamen, but not in the head of caudate nucleus, was significantly lower on the more affected side than on the less affected side (p<0.05, paired t-test. In addition, the A2ARs were significantly increased after antiparkinsonian therapy in the bilateral putamen of the drug-naïve patients (p<0.05, paired t-test but not in the bilateral head of caudate nucleus. Our study demonstrated that the A2ARs in the putamen were increased in the PD patients with dyskinesia, and also suggest that the A2ARs in the putamen compensate for the asymmetrical decrease of dopamine in drug-naïve PD patients and that antiparkinsonian therapy increases the A2ARs in the putamen. The A2ARs may play an

  14. Location Detection and Tracking of Moving Targets by a 2D IR-UWB Radar System

    Directory of Open Access Journals (Sweden)

    Van-Han Nguyen

    2015-03-01

    Full Text Available In indoor environments, the Global Positioning System (GPS and long-range tracking radar systems are not optimal, because of signal propagation limitations in the indoor environment. In recent years, the use of ultra-wide band (UWB technology has become a possible solution for object detection, localization and tracking in indoor environments, because of its high range resolution, compact size and low cost. This paper presents improved target detection and tracking techniques for moving objects with impulse-radio UWB (IR-UWB radar in a short-range indoor area. This is achieved through signal-processing steps, such as clutter reduction, target detection, target localization and tracking. In this paper, we introduce a new combination consisting of our proposed signal-processing procedures. In the clutter-reduction step, a filtering method that uses a Kalman filter (KF is proposed. Then, in the target detection step, a modification of the conventional CLEAN algorithm which is used to estimate the impulse response from observation region is applied for the advanced elimination of false alarms. Then, the output is fed into the target localization and tracking step, in which the target location and trajectory are determined and tracked by using unscented KF in two-dimensional coordinates. In each step, the proposed methods are compared to conventional methods to demonstrate the differences in performance. The experiments are carried out using actual IR-UWB radar under different scenarios. The results verify that the proposed methods can improve the probability and efficiency of target detection and tracking.

  15. Up-regulation of thromboxane A2 receptor expression by lipid soluble smoking particles through post-transcriptional mechanisms

    DEFF Research Database (Denmark)

    Zhang, Wei; Zhang, Yaping; Edvinsson, Lars

    2008-01-01

    . The present study was designed to test if lipid soluble smoking particles (DSP) enhance TxA(2) receptor (TP) expression in rat mesenteric arteries, and if intracellular mitogen-activated protein kinase (MAPK) pathways play a role. Organ culture of rat mesenteric arteries in the presence of DSP (0.2 microl...... actinomycin D, but was almost completely abolished by cycloheximide, a general translational inhibitor. Dexamethasone, a glucocorticoid, manifested a potent inhibitory effect as well. These results suggest that the up-regulation of TP receptor occurs via post-transcriptional events, and mainly translation...... are responsible for the up-regulation of TP receptor by DSP, in which enhanced translation is the major cause of the elevated protein expression and the enhanced contraction....

  16. Neuronal nicotinic acetylcholine receptors serve as sensitive targets that mediate β-amyloid neurotoxicity

    Institute of Scientific and Technical Information of China (English)

    Qiang LIU; Jie WU

    2006-01-01

    Alzheimer's disease (AD) is the most common form of brain dementia characterized by the accumulation of β-amyloid peptides (Aβ) and loss of forebrain cholinergic neurons. Aβ accumulation and aggregation are thought to contribute to cholinergic neuronal degeneration, in turn causing learning and memory deficits, but the specific targets that mediate Aβ neurotoxicity remain elusive. Recently, accumlating lines of evidence have demonstrated that Aβ directly modulates the function of neuronal nicotinic acetylcholine receptors (nAChRs), which leads to the new hypothesis that neuronal nAChRs may serve as important targets that mediate Aβ neurotoxicity. In this review, we summarize current studies performed in our laboratory and in others to address the question of how Aβ modulates neuronal nAChRs, especially nAChR subunit function.

  17. Novel anti-myeloma immunotherapies targeting the SLAM family of receptors.

    Science.gov (United States)

    Radhakrishnan, Sabarinath Venniyil; Bhardwaj, Neelam; Luetkens, Tim; Atanackovic, Djordje

    2017-01-01

    Treatment for multiple myeloma (MM) has significantly advanced in the last decade with the introduction of proteasome inhibitors and immunomodulatory therapies. Unfortunately, MM continues to cause significant morbidity and most patients eventually succumb to the disease. As in other areas of cancer, immunotherapy in MM has also evolved and holds promise to deliver long-lasting remissions or even cure. The signaling lymphocyte activation molecules (SLAM) family of surface proteins represents a group of potential targets for immunotherapy in MM as some of the family members are expressed consistently on plasma cells and also on myeloma propagating pre-plasma cells. Here, we review the SLAM family members in detail, describe their tissue distribution, biologic pathways, as well as relevant pre-clinical studies and clinical trials in MM. Our review demonstrates the value of SLAM family receptors as potential targets for anti-myeloma immunotherapies and outlines how immunotherapeutic approaches can be developed.

  18. Histamine H3 receptor as a potential target for cognitive symptoms in neuropsychiatric diseases.

    Science.gov (United States)

    Sadek, Bassem; Saad, Ali; Sadeq, Adel; Jalal, Fakhreya; Stark, Holger

    2016-10-01

    The potential contributions of the brain histaminergic system in neurodegenerative diseases, and the possiblity of histamine-targeting treatments is attracting considerable interests. The histamine H3 receptor (H3R) is expressed mainly in the central nervous system, and is, consequently, an attractive pharmacological target. Although recently described clinical trials have been disappointing in attention deficit hyperactivity disorder (ADHD) and schizophrenia (SCH), numerous H3R antagonists, including pitolisant, demonstrate potential in the treatment of narcolepsy, excessive daytime sleepiness associated with cognitive impairment, epilepsy, and Alzheimer's disease (AD). This review focuses on the recent preclinical as well as clinical results that support the relevance of H3R antagonists for the treatment of cognitive symptoms in neuropsychiatric diseases, namely AD, epilepsy and SCH. The review summarizes the role of histaminergic neurotransmission with focus on these brain disorders, as well as the effects of numerous H3R antagonists on animal models and humans.

  19. Orexin Receptor Targets for Anti-Relapse Medication Development in Drug Addiction.

    Science.gov (United States)

    Zhou, Luyi; Sun, Wei-Lun; See, Ronald E

    2011-06-14

    Drug addiction is a chronic illness characterized by high rates of relapse. Relapse to drug use can be triggered by re-exposure to drug-associated cues, stressful events, or the drug itself after a period of abstinence. Pharmacological intervention to reduce the impact of relapse-instigating factors offers a promising target for addiction treatment. Growing evidence has implicated an important role of the orexin/hypocretin system in drug reward and drug-seeking, including animal models of relapse. Here, we review the evidence for the role of orexins in modulating reward and drug-seeking in animal models of addiction and the potential for orexin receptors as specific targets for anti-relapse medication approaches.

  20. Rational Design of an Epstein-Barr Virus Vaccine Targeting the Receptor-Binding Site.

    Science.gov (United States)

    Kanekiyo, Masaru; Bu, Wei; Joyce, M Gordon; Meng, Geng; Whittle, James R R; Baxa, Ulrich; Yamamoto, Takuya; Narpala, Sandeep; Todd, John-Paul; Rao, Srinivas S; McDermott, Adrian B; Koup, Richard A; Rossmann, Michael G; Mascola, John R; Graham, Barney S; Cohen, Jeffrey I; Nabel, Gary J

    2015-08-27

    Epstein-Barr virus (EBV) represents a major global health problem. Though it is associated with infectious mononucleosis and ∼200,000 cancers annually worldwide, a vaccine is not available. The major target of immunity is EBV glycoprotein 350/220 (gp350) that mediates attachment to B cells through complement receptor 2 (CR2/CD21). Here, we created self-assembling nanoparticles that displayed different domains of gp350 in a symmetric array. By focusing presentation of the CR2-binding domain on nanoparticles, potent neutralizing antibodies were elicited in mice and non-human primates. The structurally designed nanoparticle vaccine increased neutralization 10- to 100-fold compared to soluble gp350 by targeting a functionally conserved site of vulnerability, improving vaccine-induced protection in a mouse model. This rational approach to EBV vaccine design elicited potent neutralizing antibody responses by arrayed presentation of a conserved viral entry domain, a strategy that can be applied to other viruses.

  1. Development of Bag-1L as a therapeutic target in androgen receptor-dependent prostate cancer.

    Science.gov (United States)

    Cato, Laura; Neeb, Antje; Sharp, Adam; Buzón, Victor; Ficarro, Scott B; Yang, Linxiao; Muhle-Goll, Claudia; Kuznik, Nane C; Riisnaes, Ruth; Nava Rodrigues, Daniel; Armant, Olivier; Gourain, Victor; Adelmant, Guillaume; Ntim, Emmanuel A; Westerling, Thomas; Dolling, David; Rescigno, Pasquale; Figueiredo, Ines; Fauser, Friedrich; Wu, Jennifer; Rottenberg, Jaice T; Shatkina, Liubov; Ester, Claudia; Luy, Burkhard; Puchta, Holger; Troppmair, Jakob; Jung, Nicole; Bräse, Stefan; Strähle, Uwe; Marto, Jarrod A; Nienhaus, Gerd Ulrich; Al-Lazikani, Bissan; Salvatella, Xavier; de Bono, Johann S; Cato, Andrew Cb; Brown, Myles

    2017-08-10

    Targeting the activation function-1 (AF-1) domain located in the N-terminus of the androgen receptor (AR) is an attractive therapeutic alternative to the current approaches to inhibit AR action in prostate cancer (PCa). Here we show that the AR AF-1 is bound by the cochaperone Bag-1L. Mutations in the AR interaction domain or loss of Bag-1L abrogate AR signaling and reduce PCa growth. Clinically, Bag-1L protein levels increase with progression to castration-resistant PCa (CRPC) and high levels of Bag-1L in primary PCa associate with a reduced clinical benefit from abiraterone when these tumors progress. Intriguingly, residues in Bag-1L important for its interaction with the AR AF-1 are within a potentially druggable pocket, implicating Bag-1L as a potential therapeutic target in PCa.

  2. Orexin Receptor Targets for Anti-Relapse Medication Development in Drug Addiction

    Directory of Open Access Journals (Sweden)

    Ronald E. See

    2011-06-01

    Full Text Available Drug addiction is a chronic illness characterized by high rates of relapse. Relapse to drug use can be triggered by re-exposure to drug-associated cues, stressful events, or the drug itself after a period of abstinence. Pharmacological intervention to reduce the impact of relapse-instigating factors offers a promising target for addiction treatment. Growing evidence has implicated an important role of the orexin/hypocretin system in drug reward and drug-seeking, including animal models of relapse. Here, we review the evidence for the role of orexins in modulating reward and drug-seeking in animal models of addiction and the potential for orexin receptors as specific targets for anti-relapse medication approaches.

  3. Adenosine enhances sweet taste through A2B receptors in the taste bud.

    Science.gov (United States)

    Dando, Robin; Dvoryanchikov, Gennady; Pereira, Elizabeth; Chaudhari, Nirupa; Roper, Stephen D

    2012-01-01

    Mammalian taste buds use ATP as a neurotransmitter. Taste Receptor (type II) cells secrete ATP via gap junction hemichannels into the narrow extracellular spaces within a taste bud. This ATP excites primary sensory afferent fibers and also stimulates neighboring taste bud cells. Here we show that extracellular ATP is enzymatically degraded to adenosine within mouse vallate taste buds and that this nucleoside acts as an autocrine neuromodulator to selectively enhance sweet taste. In Receptor cells in a lingual slice preparation, Ca(2+) mobilization evoked by focally applied artificial sweeteners was significantly enhanced by adenosine (50 μM). Adenosine had no effect on bitter or umami taste responses, and the nucleoside did not affect Presynaptic (type III) taste cells. We also used biosensor cells to measure transmitter release from isolated taste buds. Adenosine (5 μM) enhanced ATP release evoked by sweet but not bitter taste stimuli. Using single-cell reverse transcriptase (RT)-PCR on isolated vallate taste cells, we show that many Receptor cells express the adenosine receptor, Adora2b, while Presynaptic (type III) and Glial-like (type I) cells seldom do. Furthermore, Adora2b receptors are significantly associated with expression of the sweet taste receptor subunit, Tas1r2. Adenosine is generated during taste stimulation mainly by the action of the ecto-5'-nucleotidase, NT5E, and to a lesser extent, prostatic acid phosphatase. Both these ecto-nucleotidases are expressed by Presynaptic cells, as shown by single-cell RT-PCR, enzyme histochemistry, and immunofluorescence. Our findings suggest that ATP released during taste reception is degraded to adenosine to exert positive modulation particularly on sweet taste.

  4. Functional expression of adenosine A2A and A3 receptors in the mouse dendritic cell line XS-106.

    Science.gov (United States)

    Dickenson, John M; Reeder, Steve; Rees, Bob; Alexander, Steve; Kendall, Dave

    2003-08-01

    There is increasing evidence to suggest that adenosine receptors can modulate the function of cells involved in the immune system. For example, human dendritic cells derived from blood monocytes have recently been described to express functional adenosine A1, A2A and A3 receptors. Therefore, in the present study, we have investigated whether the recently established murine dendritic cell line XS-106 expresses functional adenosine receptors. The selective adenosine A3 receptor agonist 1-[2-chloro-6[[(3-iodophenyl)methyl]amino]-9H-purin-9-yl]-1-deoxy-N-methyl-beta-D-ribofuranuronamide (2-Cl-IB-MECA) inhibited forskolin-mediated [3H]cyclic AMP accumulation and stimulated concentration-dependent increases in p42/p44 mitogen-activated protein kinase (MAPK) phosphorylation. The selective adenosine A2A receptor agonist 4-[2-[[-6-amino-9-(N-ethyl-beta-D-ribofuranuronamidosyl)-9H-purin-2-yl]amino]ethyl]benzene-propanoic acid (CGS 21680) stimulated a robust increase in [3H]cyclic AMP accumulation and p42/p44 MAPK phosphorylation. In contrast, the selective adenosine A1 receptor agonist CPA (N6-cyclopentyladenosine) did not inhibit forskolin-mediated [3H]cyclic AMP accumulation or stimulate increases in p42/p44 MAPK phosphorylation. These observations suggest that XS-106 cells express functional adenosine A2A and A3 receptors. The non-selective adenosine receptor agonist 5'-N-ethylcarboxamidoadenosine (NECA) inhibited lipopolysaccharide-induced tumour necrosis factor-alpha (TNF-alpha) release from XS-106 cells in a concentration-dependent fashion. Furthermore, treatment with Cl-IB-MECA (1 microM) or CGS 21680 (1 microM) alone produced a partial inhibition of lipopolysaccharide-induced TNF-alpha release (when compared to NECA), whereas a combination of both agonists resulted in the inhibition of TNF-alpha release comparable to that observed with NECA alone. Treatment of cells with the adenosine A2A receptor selective antagonists 4-(2-[7-amino-2-(2-furyl)[1,2,4]triazolo[2,3-a

  5. Inhibitory effects of benzodiazepines on the adenosine A(2B) receptor mediated secretion of interleukin-8 in human mast cells.

    Science.gov (United States)

    Hoffmann, Kristina; Xifró, Rosa Altarcheh; Hartweg, Julia Lisa; Spitzlei, Petra; Meis, Kirsten; Molderings, Gerhard J; von Kügelgen, Ivar

    2013-01-30

    The activation of adenosine A(2B) receptors in human mast cells causes pro-inflammatory responses such as the secretion of interleukin-8. There is evidence for an inhibitory effect of benzodiazepines on mast cell mediated symptoms in patients with systemic mast cell activation disease. Therefore, we investigated the effects of benzodiazepines on adenosine A(2B) receptor mediated interleukin-8 production in human mast cell leukaemia (HMC1) cells by an enzyme linked immunosorbent assay. The adenosine analogue N-ethylcarboxamidoadenosine (NECA, 0.3-3 μM) increased interleukin-8 production about 5-fold above baseline. This effect was attenuated by the adenosine A(2B) receptor antagonist MRS1754 (N-(4-cyanophenyl)-2-{4-(2,3,6,7-tetrahydro-2,6-dioxo-1,3-dipropyl-1H-purin-8-yl)phenoxy}-acetamide) 1 μM. In addition, diazepam, 4'-chlorodiazepam and flunitrazepam (1-30 μM) markedly reduced NECA-induced interleukin-8 production in that order of potency, whereas clonazepam showed only a modest inhibition. The inhibitory effect of diazepam was not altered by flumazenil 10 μM or PK11195 (1-(2-chlorophenyl)-N-methyl-N-(1-methylpropyl)-3-isoquinolinecarboxamide) 10 μM. Diazepam attenuated the NECA-induced expression of mRNA encoding for interleukin-8. Moreover, diazepam and flunitrazepam reduced the increasing effects of NECA on cAMP-response element- and nuclear factor of activated t-cells-driven luciferase reporter gene activities in HMC1 cells. Neither diazepam nor flunitrazepam affected NECA-induced increases in cellular cAMP levels in CHO Flp-In cells stably expressing recombinant human adenosine A(2B) receptors, excluding a direct action of benzodiazepines on human adenosine A(2B) receptors. In conclusion, this is the first study showing an inhibitory action of benzodiazepines on adenosine A(2B) receptor mediated interleukin-8 production in human mast (HMC1) cells. The rank order of potency indicates the involvement of an atypical benzodiazepine binding site.

  6. microRNA-150 inhibits the formation of macrophage foam cells through targeting adiponectin receptor 2

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jing [Department of Geratory, Linzi District People’s Hospital of Zibo City, Zibo, Shandong (China); Zhang, Suhua, E-mail: drsuhuangzhang@qq.com [Department of HealthCare, Qilu Hospital of Shandong University (Qingdao), Qingdao City, Qingdao (China)

    2016-08-05

    Transformation of macrophages into foam cells plays a critical role in the pathogenesis of atherosclerosis. The aim of this study was to determine the expression and biological roles of microRNA (miR)-150 in the formation of macrophage foam cells and to identify its functional target(s). Exposure to 50 μg/ml oxidized low-density lipoprotein (oxLDL) led to a significant upregulation of miR-150 in THP-1 macrophages. Overexpression of miR-150 inhibited oxLDL-induced lipid accumulation in THP-1 macrophages, while knockdown of miR-150 enhanced lipid accumulation. apoA-I- and HDL-mediated cholesterol efflux was increased by 66% and 43%, respectively, in miR-150-overexpressing macrophages relative to control cells. In contrast, downregulation of miR-150 significantly reduced cholesterol efflux from oxLDL-laden macrophages. Bioinformatic analysis and luciferase reporter assay revealed adiponectin receptor 2 (AdipoR2) as a direct target of miR-150. Small interfering RNA-mediated downregulation of AdipoR2 phenocopied the effects of miR-150 overexpression, reducing lipid accumulation and facilitating cholesterol efflux in oxLDL-treated THP-1 macrophages. Knockdown of AdipoR2 induced the expression of proliferator-activated receptor gamma (PPARγ), liver X receptor alpha (LXRα), ABCA1, and ABCG1. Moreover, pharmacological inhibition of PPARγ or LXRα impaired AdipoR2 silencing-induced upregulation of ABCA1 and ABCG1. Taken together, our results indicate that miR-150 can attenuate oxLDL-induced lipid accumulation in macrophages via promotion of cholesterol efflux. The suppressive effects of miR-150 on macrophage foam cell formation are mediated through targeting of AdipoR2. Delivery of miR-150 may represent a potential approach to prevent macrophage foam cell formation in atherosclerosis. -- Highlights: •miR-150 inhibits macrophage foam cell formation. •miR-150 accelerates cholesterol efflux from oxLDL-laden macrophages. •miR-150 suppresses macrophage foam cell

  7. Role of A1 and A2A adenosine receptor agonists in adipose tissue inflammation induced by obesity in mice.

    Science.gov (United States)

    DeOliveira, Caroline Candida; Paiva Caria, Cintia Rabelo E; Ferreira Gotardo, Erica Martins; Ribeiro, Marcelo Lima; Gambero, Alessandra

    2017-03-15

    Adenosine receptors are expressed in adipose tissue and control physiological and pathological events such as lipolysis and inflammation. The aim of this study was to evaluate the activity of N(6)-cyclopentyladenosine (CPA), a potent and selective A1 adenosine receptor agonist; 2-p-(2-carboxyethyl)phenethylamino-5'-N-ethylcarboxyamidoadenosine hydrochloride (CGS-21680), an A2A adenosine receptor agonist; and 5'-N-ethylcarboxamidoadenosine (NECA), a potent non-selective adenosine receptor agonist on adipose tissue inflammatory alterations induced by obesity in mice. Swiss mice were fed with a high-fat diet for 12 weeks and agonists were administered in the last two weeks. Body weight, adiposity and glucose homeostasis were evaluated. Inflammation in adipose tissue was assessed by evaluation of adipokine production and macrophage infiltration. Adenosine receptor signaling in adipose tissue was also evaluated. Mice that received CGS21680 presented an improvement in glucose homeostasis in association with systemically reduced inflammatory markers (TNF-α, PAI-1) and in the visceral adipose tissue (TNF-α, MCP-1, macrophage infiltration). Activation of p38 signaling was found in adipose tissue of this group of mice. NECA-treated mice presented some improvements in glucose homeostasis associated with an observed weight loss. Mice that received CPA presented only a reduction in the ex vivo basal lipolysis rate measured within visceral adipose tissue. In conclusion, administration of the A2A receptor agonist to obese mice resulted in improvements in glucose homeostasis and adipose tissue inflammation, corroborating the idea that new therapeutics to treat obesity could emerge from these compounds. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Expression and therapeutic targeting of dopamine receptor-1 (D1R) in breast cancer.

    Science.gov (United States)

    Borcherding, D C; Tong, W; Hugo, E R; Barnard, D F; Fox, S; LaSance, K; Shaughnessy, E; Ben-Jonathan, N

    2016-06-16

    Patients with advanced breast cancer often fail to respond to treatment, creating a need to develop novel biomarkers and effective therapeutics. Dopamine (DA) is a catecholamine that binds to five G protein-coupled receptors. We discovered expression of DA type-1 receptors (D1Rs) in breast cancer, thereby identifying these receptors as novel therapeutic targets in this disease. Strong to moderate immunoreactive D1R expression was found in 30% of 751 primary breast carcinomas, and was associated with larger tumors, higher tumor grades, node metastasis and shorter patient survival. DA and D1R agonists, signaling through the cGMP/protein kinase G (PKG) pathway, suppressed cell viability, inhibited invasion and induced apoptosis in multiple breast cancer cell lines. Fenoldopam, a peripheral D1R agonist that does not penetrate the brain, dramatically suppressed tumor growth in two mouse models with D1R-expressing xenografts by increasing both necrosis and apoptosis. D1R-expressing primary tumors and metastases in mice were detected by fluorescence imaging. In conclusion, D1R overexpression is associated with advanced breast cancer and poor prognosis. Activation of the D1R/cGMP/PKG pathway induces apoptosis in vitro and causes tumor shrinkage in vivo. Fenoldopam, which is FDA (Food and Drug Administration) approved to treat renal hypertension, could be repurposed as a novel therapeutic agent for patients with D1R-expressing tumors.

  9. Orexin-corticotropin-releasing factor receptor heteromers in the ventral tegmental area as targets for cocaine.

    Science.gov (United States)

    Navarro, Gemma; Quiroz, César; Moreno-Delgado, David; Sierakowiak, Adam; McDowell, Kimberly; Moreno, Estefanía; Rea, William; Cai, Ning-Sheng; Aguinaga, David; Howell, Lesley A; Hausch, Felix; Cortés, Antonio; Mallol, Josefa; Casadó, Vicent; Lluís, Carme; Canela, Enric I; Ferré, Sergi; McCormick, Peter J

    2015-04-29

    Release of the neuropeptides corticotropin-releasing factor (CRF) and orexin-A in the ventral tegmental area (VTA) play an important role in stress-induced cocaine-seeking behavior. We provide evidence for pharmacologically significant interactions between CRF and orexin-A that depend on oligomerization of CRF1 receptor (CRF1R) and orexin OX1 receptors (OX1R). CRF1R-OX1R heteromers are the conduits of a negative crosstalk between orexin-A and CRF as demonstrated in transfected cells and rat VTA, in which they significantly modulate dendritic dopamine release. The cocaine target σ1 receptor (σ1R) also associates with the CRF1R-OX1R heteromer. Cocaine binding to the σ1R-CRF1R-OX1R complex promotes a long-term disruption of the orexin-A-CRF negative crosstalk. Through this mechanism, cocaine sensitizes VTA cells to the excitatory effects of both CRF and orexin-A, thus providing a mechanism by which stress induces cocaine seeking.

  10. Methylphenidate and μ opioid receptor interactions: a pharmacological target for prevention of stimulant abuse.

    Science.gov (United States)

    Zhu, Jinmin; Spencer, Thomas J; Liu-Chen, Lee-Yuan; Biederman, Joseph; Bhide, Pradeep G

    2011-01-01

    Methylphenidate (MPH) is one of the most commonly used and highly effective treatments for attention deficit hyperactivity disorder (ADHD) in children and adults. As the therapeutic use of MPH has increased, so has its abuse and illicit street-use. Yet, the mechanisms associated with development of MPH-associated abuse and dependence are not well understood making it difficult to develop methods to help its mitigation. As a result, many ADHD patients especially children and youth, that could benefit from MPH treatment do not receive it and risk lifelong disabilities associated with untreated ADHD. Therefore, understanding the mechanisms associated with development of MPH addiction and designing methods to prevent it assume high public health significance. Using a mouse model we show that supra-therapeutic doses of MPH produce rewarding effects (surrogate measure for addiction in humans) in a conditioned place preference paradigm and upregulate μ opioid receptor (MOPR) activity in the striatum and nucleus accumbens, brain regions associated with reward circuitry. Co-administration of naltrexone, a non-selective opioid receptor antagonist, prevents MPH-induced MOPR activation and the rewarding effects. The MPH-induced MOPR activation and rewarding effect require activation of the dopamine D1 but not the D2-receptor. These findings identify the MOPR as a potential target for attenuating rewarding effects of MPH and suggest that a formulation that combines naltrexone with MPH could be a useful pharmaceutical approach to alleviate abuse potential of MPH and other stimulants.

  11. Free fatty acid receptors as therapeutic targets for the treatment of diabetes

    Directory of Open Access Journals (Sweden)

    Atsuhiko eIchimura

    2014-11-01

    Full Text Available Nutrition regulates energy balance; however, dysfunction of energy balance can cause metabolic disorders, such as obesity and diabetes. Fatty acids are an essential energy source and signaling molecules that regulate various cellular processes and physiological functions. Recently, several orphan G protein-coupled receptors were indentified as free fatty acid receptors (FFARs. GPR40/FFAR1 and GPR120/FFAR4 are activated by medium- and/or long-chain fatty acids, whereas GPR41/FFAR3 and GPR43/FFAR2 are activated by short-chain fatty acids. FFARs are regarded as targets for novel drugs to treat metabolic disorders, such as obesity and type 2 diabetes, because recent studies have showed that these receptors are involved in the energy metabolism in various tissues, including adipose, intestinal, and immune tissue. In this review, we summarize physiological roles of the FFARs, provide a comprehensive overview of energy regulation by FFARs, and discuss new prospects for treatment of metabolic disorders.

  12. Saffron reduces ATP-induced retinal cytotoxicity by targeting P2X7 receptors.

    Science.gov (United States)

    Corso, Lucia; Cavallero, Anna; Baroni, Debora; Garbati, Patrizia; Prestipino, Gianfranco; Bisti, Silvia; Nobile, Mario; Picco, Cristiana

    2016-03-01

    P2X7-type purinergic receptors are distributed throughout the nervous system where they contribute to physiological and pathological functions. In the retina, this receptor is found in both inner and outer cells including microglia modulating signaling and health of retinal cells. It is involved in retinal neurodegenerative disorders such as retinitis pigmentosa and age-related macular degeneration (AMD). Experimental studies demonstrated that saffron protects photoreceptors from light-induced damage preserving both retinal morphology and visual function and improves retinal flicker sensitivity in AMD patients. To evaluate a possible interaction between saffron and P2X7 receptors (P2X7Rs), different cellular models and experimental approaches were used. We found that saffron positively influences the viability of mouse primary retinal cells and photoreceptor-derived 661W cells exposed to ATP, and reduced the ATP-induced intracellular calcium increase in 661W cells. Similar results were obtained on HEK cells transfected with recombinant rat P2X7R but not on cells transfected with rat P2X2R. Finally, patch-clamp experiments showed that saffron inhibited cationic currents in HEK-P2X7R cells. These results point out a novel mechanism through which saffron may exert its protective role in neurodegeneration and support the idea that P2X7-mediated calcium signaling may be a crucial therapeutic target in the treatment of neurodegenerative diseases.

  13. Loss of the membrane anchor of the target receptor is a mechanism of bioinsecticide resistance.

    Science.gov (United States)

    Darboux, Isabelle; Pauchet, Yannick; Castella, Claude; Silva-Filha, Maria Helena; Nielsen-LeRoux, Christina; Charles, Jean-François; Pauron, David

    2002-04-30

    The mosquitocidal activity of Bacillus sphaericus is because of a binary toxin (Bin), which binds to Culex pipiens maltase 1 (Cpm1), an alpha-glucosidase present in the midgut of Culex pipiens larvae. In this work, we studied the molecular basis of the resistance to Bin developed by a strain (GEO) of C. pipiens. Immunohistochemical and in situ hybridization experiments showed that Cpm1 was undetectable in the midgut of GEO larvae, although the gene was correctly transcribed. The sequence of the cpm1(GEO) cDNA differs from the sequence we previously reported for a susceptible strain (cpm1(IP)) by seven mutations: six missense mutations and a mutation leading to the premature termination of translation. When produced in insect cells, Cpm1(IP) was attached to the membrane by a glycosylphosphatidylinositol (GPI). In contrast, the premature termination of translation of Cpm1(GEO) resulted in the targeting of the protein to the extracellular compartment because of truncation of the GPI-anchoring site. The interaction between Bin and Cpm1(GEO) and the enzyme activity of the receptor were not affected. Thus, Bin is not toxic to GEO larvae because it cannot interact with the midgut cell membrane, even though its receptor site is unaffected. This mechanism contrasts with other known resistance mechanisms in which point mutations decrease the affinity of binding between the receptor and the toxin.

  14. Peroxisome proliferator-activated receptor gamma in bladder cancer: a promising therapeutic target.

    Science.gov (United States)

    Mansure, Jose J; Nassim, Roland; Kassouf, Wassim

    2009-04-01

    Peroxisome Proliferator-Activated Receptors (PPARs) are ligand-activated intracellular transcription factors, members of the nuclear hormone receptor superfamily. The PPAR subfamily consist of three subtypes encoded by distinct genes denoted PPARalpha, PPARbeta/delta, and PPARgamma. The peroxisome proliferator-activated receptor gamma (PPARgamma) is the most extensively studied subtype of the PPARs. Over the last decade, research on PPARgamma unveiled its role in important biological processes, including lipid biosynthesis, glucose metabolism, anti-inflammatory response, and atherosclerosis. Recently, PPARgamma has been shown to be expressed in many cancers including, lung, prostate, bladder, colon, breast, duodenal, thyroid, and has been demonstrated to potentially play an important role in carcinogenesis. In bladder cancer, PPARgamma ligands such as troglitazone and 15d-PGJ2 have shown to inhibit tumor growth. We have recently published the first report to show that a new class of PPARgamma agonists, PPARgamma-active C-DIMs, which are more potent than the previous generation of drugs, exhibit anti-tumorigenic activity against bladder cancer cells in vitro and bladder tumors in vivo. The following review will discuss the molecular structure of PPARgamma, its function and its role in cancer biology and how it is emerging as a promising therapeutic target in bladder cancer.

  15. Subarachnoid hemorrhage induces enhanced expression of thromboxane A2 receptors in rat cerebral arteries

    DEFF Research Database (Denmark)

    Ansar, Saema; Larsen, Carl; Maddahi, Aida;

    2010-01-01

    after SAH in cerebral arteries. SAH was induced in rats by injecting 250 microl of blood into the prechiasmatic cistern. Two days after the SAH, cerebral arteries were harvested and contractile responses to the TP receptor agonist U46619 were investigated with myographs. In addition, the contractile...

  16. Chlorin e6 Conjugated Interleukin-6 Receptor Aptamers Selectively Kill Target Cells Upon Irradiation

    Directory of Open Access Journals (Sweden)

    Sven Kruspe

    2014-01-01

    Full Text Available Photodynamic therapy (PDT uses the therapeutic properties of light in combination with certain chemicals, called photosensitizers, to successfully treat brain, breast, prostate, and skin cancers. To improve PDT, current research focuses on the development of photosensitizers to specifically target cancer cells. In the past few years, aptamers have been developed to directly deliver cargo molecules into target cells. We conjugated the photosensitizer chlorin e6 (ce6 with a human interleukin-6 receptor (IL-6R binding RNA aptamer, AIR-3A yielding AIR-3A-ce6 for application in high efficient PDT. AIR-3A-ce6 was rapidly and specifically internalized by IL-6R presenting (IL-6R+ cells. Upon light irradiation, targeted cells were selectively killed, while free ce6 did not show any toxic effect. Cells lacking the IL-6R were also not affected by AIR-3A-ce6. With this approach, we improved the target specificity of ce6-mediated PDT. In the future, other tumor-specific aptamers might be used to selectively localize photosensitizers into cells of interest and improve the efficacy and specificity of PDT in cancer and other diseases.

  17. Targeting angiotensin II type 2 receptor pathways to treat neuropathic pain and inflammatory pain.

    Science.gov (United States)

    Smith, Maree T; Muralidharan, Arjun

    2015-01-01

    Neuropathic pain and chronic inflammatory pain are large unmet medical needs. Over the past two decades, numerous 'pain targets' have been identified for analgesic drug discovery. Despite promising results in rodent pain models, many compounds modulating such targets lacked efficacy in clinical trials. An exception is oral EMA401, a small-molecule angiotensin II type 2 receptor (AT2R) antagonist. Herein, angiotensin II/AT2R signaling-induced hyperexcitability and abnormal sprouting of cultured dorsal root ganglion neurons, together with radioligand binding, pharmacokinetics, analgesic efficacy and mode of action of small-molecule AT2R antagonists in rodent models of peripheral neuropathic and chronic inflammatory pain, are reviewed. The findings of a successful Phase IIa clinical trial of EMA401 in patients with neuropathic pain are presented in brief. The functional importance of angiotensin II/AT2R signaling has remained enigmatic for decades, and there are no clinically available medications that target the AT2R. However, on the basis of preclinical findings and recent clinical trial data showing that the peripherally restricted, small-molecule AT2R antagonist, EMA401, successfully alleviated neuropathic pain in a Phase II clinical trial, the AT2R is receiving considerable attention as a new therapeutic target with human validation for the relief of peripheral neuropathic and chronic inflammatory pain conditions.

  18. Brain-Specific Homeobox Factor as a Target Selector for Glucocorticoid Receptor in Energy Balance

    Science.gov (United States)

    Lee, Bora; Kim, Sun-Gyun; Kim, Juhee; Choi, Kwan Yong; Lee, Soo-Kyung

    2013-01-01

    The molecular basis underlying the physiologically well-defined orexigenic function of glucocorticoid (Gc) is unclear. Brain-specific homeobox factor (Bsx) is a positive regulator of the orexigenic neuropeptide, agouti-related peptide (AgRP), in AgRP neurons of the hypothalamic arcuate nucleus. Here, we show that in response to fasting-elevated Gc levels, Gc receptor (GR) and Bsx synergize to direct activation of AgRP transcription. This synergy is dictated by unique sequence features in a novel Gc response element in AgRP (AgRP-GRE). In contrast to AgRP-GRE, Bsx suppresses transactivation directed by many conventional GREs, functioning as a gene context-dependent modulator of GR actions or a target selector for GR. Consistent with this finding, AgRP-GRE drives fasting-dependent activation of a target gene specifically in GR+ Bsx+ AgRP neurons. These results define AgRP as a common orexigenic target gene of GR and Bsx and provide an opportunity to identify their additional common targets, facilitating our understanding of the molecular basis underlying the orexigenic activity of Gc and Bsx. PMID:23671185

  19. A folate receptor-targeted lipoplex delivering interleukin-15 gene for colon cancer immunotherapy.

    Science.gov (United States)

    Liang, Xiao; Luo, Min; Wei, Xia-Wei; Ma, Cui-Cui; Yang, Yu-Han; Shao, Bin; Liu, Yan-Tong; Liu, Ting; Ren, Jun; Liu, Li; He, Zhi-Yao; Wei, Yu-Quan

    2016-08-09

    Interleukin-15 has been implicated as a promising cytokine for cancer immunotherapy, while folate receptor α (FRα) has been shown to be a potentially useful target for colon cancer therapy. Herein, we developed F-PLP/pIL15, a FRα-targeted lipoplex loading recombinant interleukin-15 plasmid (pIL15) and studied its antitumor effects in vivo using a CT26 colon cancer mouse model. Compared with control (normal saline) treatment, F-PLP/pIL15 significantly suppressed tumor growth in regard to tumor weight (P targeted delivery of IL15 gene might be associated with its in vivo antitumor effects, which include inducing tumor cell apoptosis, inhibiting tumor proliferation and promoting the activation of immune cells such as T cells and natural killer cells. Furthermore, hematoxylin and eosin staining of vital organs following F-PLP/pIL15 treatment showed no detectable toxicity, thus indicating that intraperitoneal administration may be a viable route of delivery. Overall, these results suggest that F-PLP/pIL15 may serve as a potential targeting preparation for colon cancer therapy.

  20. Accessing Structurally Diverse Near-Infrared Cyanine Dyes for Folate Receptor-Targeted Cancer Cell Staining.

    Science.gov (United States)

    König, Sandra G; Krämer, Roland

    2017-03-24

    Folate receptor (FR) targeting is one of the most promising strategies for the development of small-molecule based cancer imaging agents since the FR is highly overexpressed on the surface of many cancer cell types. FR-targeted conjugates of NIR emissive cyanine dyes are in advanced clinical trials for fluorescence-guided surgery and are valuable research tools for optical molecular imaging in animal models. Only a small number of promising conjugates has been evaluated so far. Analysis of structure-performance relations to identify critical factors modulating the performance of targeted conjugates is essential for successful further optimization. This contribution addresses the need for convenient synthetic access to structurally diverse NIR-emissive cyanine dyes for conjugation with folic acid. Structural variations were introduced to readily available cyanine precursors in particular via C-C-coupling reactions including Suzuki- and (for the first time with these types of dyes) Sonogashira cross couplings. Photophysical properties such as absorbance maxima, brightness, and photostability are highly dependent on the molecular structure. Selected modified cyanines were conjugated to folic acid for cancer cell targeting. Several conjugates display a favorable combination of high fluorescence brightness and photostability with high affinity to FR positive cancer cells, and enable the selective imaging of these cells with low background.

  1. Brain-specific homeobox factor as a target selector for glucocorticoid receptor in energy balance.

    Science.gov (United States)

    Lee, Bora; Kim, Sun-Gyun; Kim, Juhee; Choi, Kwan Yong; Lee, Seunghee; Lee, Soo-Kyung; Lee, Jae W

    2013-07-01

    The molecular basis underlying the physiologically well-defined orexigenic function of glucocorticoid (Gc) is unclear. Brain-specific homeobox factor (Bsx) is a positive regulator of the orexigenic neuropeptide, agouti-related peptide (AgRP), in AgRP neurons of the hypothalamic arcuate nucleus. Here, we show that in response to fasting-elevated Gc levels, Gc receptor (GR) and Bsx synergize to direct activation of AgRP transcription. This synergy is dictated by unique sequence features in a novel Gc response element in AgRP (AgRP-GRE). In contrast to AgRP-GRE, Bsx suppresses transactivation directed by many conventional GREs, functioning as a gene context-dependent modulator of GR actions or a target selector for GR. Consistent with this finding, AgRP-GRE drives fasting-dependent activation of a target gene specifically in GR(+) Bsx(+) AgRP neurons. These results define AgRP as a common orexigenic target gene of GR and Bsx and provide an opportunity to identify their additional common targets, facilitating our understanding of the molecular basis underlying the orexigenic activity of Gc and Bsx.

  2. Fibroblast Growth Factor Receptor (FGFR): A New Target for Non-small Cell Lung Cancer Therapy.

    Science.gov (United States)

    Biello, Federica; Burrafato, Giovanni; Rijavec, Erika; Genova, Carlo; Barletta, Giulia; Truini, Anna; Coco, Simona; Bello, Maria Giovanna Dal; Alama, Angela; Boccardo, Francesco; Grossi, Francesco

    2016-01-01

    Lung cancer is still the leading cause of cancer related death worldwide. Fibroblast growth factor receptor (FGFR) is a tirosine-kinase receptor that is seen to be amplified or mutated in non-small cell lung cancer (NSCLC) and it plays a crucial role in tumour development and maintenance. The authors analyzed the state of the art of FGFR by reviewing the current literature. Fibroblast growth factor (FGF)-FGFR pathway and their aberrations are described, with the evaluation of their possible prognostic role in NSCLC and in particular in squamous cell carcinomas, in which FGFR is more often amplified. New therapeutic agents targeting FGFR signaling have been developed and are now in clinical evaluation. Dysregulation of FGF signaling in tumour cells is related to FGFR gene amplification or mutation, although it is still uncertain which of these aberrations represents a real predictor of response to specific inhibitors. However, recent evidence has questioned whether FGFR is a real target in squamous cell histology. The effectiveness of FGFR inhibitors is also still unclear since there are no clinical data on selected patients. Moreover, the management of specific side effects related to inhibition of the physiological role of FGF should be more thorough.

  3. Moving Beyond the Androgen Receptor (AR): Targeting AR-Interacting Proteins to Treat Prostate Cancer.

    Science.gov (United States)

    Foley, Christopher; Mitsiades, Nicholas

    2016-04-01

    Medical or surgical castration serves as the backbone of systemic therapy for advanced and metastatic prostate cancer, taking advantage of the importance of androgen signaling in this disease. Unfortunately, resistance to castration emerges almost universally. Despite the development and approval of new and more potent androgen synthesis inhibitors and androgen receptor (AR) antagonists, prostate cancers continue to develop resistance to these therapeutics, while often maintaining their dependence on the AR signaling axis. This highlights the need for innovative therapeutic approaches that aim to continue disrupting AR downstream signaling but are orthogonal to directly targeting the AR itself. In this review, we discuss the preclinical research that has been done, as well as clinical trials for prostate cancer, on inhibiting several important families of AR-interacting proteins, including chaperones (such as heat shock protein 90 (HSP90) and FKBP52), pioneer factors (including forkhead box protein A1 (FOXA1) and GATA-2), and AR transcriptional coregulators such as the p160 steroid receptor coactivators (SRCs) SRC-1, SRC-2, SRC-3, as well as lysine deacetylases (KDACs) and lysine acetyltransferases (KATs). Researching the effect of-and developing new therapeutic agents that target-the AR signaling axis is critical to advancing our understanding of prostate cancer biology, to continue to improve treatments for prostate cancer and for overcoming castration resistance.

  4. Targeting Human Mast Cells Expressing G-Protein-Coupled Receptors in Allergic Diseases

    Directory of Open Access Journals (Sweden)

    Yoshimichi Okayama

    2008-01-01

    Full Text Available The G-protein-coupled receptors (GPCRs are the largest known group of integral membrane receptor proteins and are the most common targets of pharmacotherapy. Mast cells (MCs have been reported to play an important role in allergic diseases, such as urticaria and bronchial asthma. There is an increasing body of clinical evidence that MCs are recruited into allergic reactions by non-IgE-dependent mechanisms. Human MCs are activated and secrete histamine in response to neuropeptides, such as substance P and somatostatin, mediated by a GPCR, MRGX2. The microenvironment surrounding MCs in their resident tissues is likely to contain multiple factors that modify antigen-dependent MC activation. MCs express various GPCRs, and since the function of human MCs is modulated by various GPCR ligands, such as adenosine and sphingosine-1-phosphate, which are present in high levels in the bronchial alveolar lavage fluid of asthmatic patients, the GPCRs expressed on MCs may play an important role in human allergic diseases. The GPCRs expressed on MCs may serve as drug targets for the treatment of allergic diseases.

  5. Modifying 5-HT1A receptor gene expression as a new target for antidepressant therapy

    Directory of Open Access Journals (Sweden)

    Paul R Albert

    2010-06-01

    Full Text Available Major depression is the most common form of mental illness, and is treated with antidepressant compounds that increase serotonin (5-HT neurotransmission. Increased 5-HT1A autoreceptor levels in the raphe nuclei act as a “brake” to inhibit the 5-HT system, leading to depression and resistance to antidepressants. Several 5-HT1A receptor agonists (buspirone, flesinoxan, ipsapirone that preferentially desensitize 5-HT1A autoreceptors have been tested for augmentation of antidepressant drugs with mixed results. One explanation could be the presence of the C(-1019G 5-HT1A promoter polymorphism that prevents gene repression of the 5-HT1A autoreceptor. Furthermore, down-regulation of 5-HT1A autoreceptor expression, not simply desensitization of receptor signaling, appears to be required to enhance and accelerate antidepressant action. The current review focuses on the transcriptional regulators of 5-HT1A autoreceptor expression, their roles in permitting response to 5-HT1A-targeted treatments and their potential as targets for new antidepressant compounds for treatment-resistant depression.

  6. SUMOylation modulates the transcriptional activity of androgen receptor in a target gene and pathway selective manner.

    Science.gov (United States)

    Sutinen, Päivi; Malinen, Marjo; Heikkinen, Sami; Palvimo, Jorma J

    2014-07-01

    Androgen receptor (AR) plays an important regulatory role in prostate cancer. AR's transcriptional activity is regulated by androgenic ligands, but also by post-translational modifications, such as SUMOylation. To study the role of AR SUMOylation in genuine chromatin environment, we compared androgen-regulated gene expression and AR chromatin occupancy in PC-3 prostate cancer cell lines stably expressing wild-type (wt) or doubly SUMOylation site-mutated AR (AR-K386R,K520R). Our genome-wide gene expression analyses reveal that the SUMOylation modulates the AR function in a target gene and pathway selective manner. The transcripts that are differentially regulated by androgen and SUMOylation are linked to cellular movement, cell death, cellular proliferation, cellular development and cell cycle. Fittingly, SUMOylation mutant AR cells proliferate faster and are more sensitive to apoptosis. Moreover, ChIP-seq analyses show that the SUMOylation can modulate the chromatin occupancy of AR on many loci in a fashion that parallels their differential androgen-regulated expression. De novo motif analyses reveal that FOXA1, C/EBP and AP-1 motifs are differentially enriched at the wtAR- and the AR-K386R,K520R-preferred genomic binding positions. Taken together, our data indicate that SUMOylation does not simply repress the AR activity, but it regulates AR's interaction with the chromatin and the receptor's target gene selection.

  7. A Cholecystokinin B Receptor-Specific DNA Aptamer for Targeting Pancreatic Ductal Adenocarcinoma

    Science.gov (United States)

    Abraham, Thomas; Pan, Weihua; Tang, Xiaomeng; Linton, Samuel S.; McGovern, Christopher O.; Loc, Welley S.; Smith, Jill P.; Butler, Peter J.; Kester, Mark; Adair, James H.; Matters, Gail L.

    2017-01-01

    Pancreatic ductal adenocarcinomas (PDACs) constitutively express the G-protein-coupled cholecystokinin B receptor (CCKBR). In this study, we identified DNA aptamers (APs) that bind to the CCKBR and describe their characterization and targeting efficacy. Using dual SELEX selection against “exposed” CCKBR peptides and CCKBR-expressing PDAC cells, a pool of DNA APs was identified. Further downselection was based on predicted structures and properties, and we selected eight APs for initial characterizations. The APs bound specifically to the CCKBR, and we showed not only that they did not stimulate proliferation of PDAC cell lines but rather inhibited their proliferation. We chose one AP, termed AP1153, for further binding and localization studies. We found that AP1153 did not activate CCKBR signaling pathways, and three-dimensional Confocal microscopy showed that AP1153 was internalized by PDAC cells in a receptor-mediated manner. AP1153 showed a binding affinity of 15 pM. Bioconjugation of AP1153 to the surface of fluorescent NPs greatly facilitated delivery of NPs to PDAC tumors in vivo. The selectivity of this AP-targeted NP delivery system holds promise for enhanced early detection of PDAC lesions as well as improved chemotherapeutic treatments for PDAC patients. PMID:27754762

  8. Peroxisome proliferator-activated receptors (PPARs) as therapeutic target in neurodegenerative disorders.

    Science.gov (United States)

    Agarwal, Swati; Yadav, Anuradha; Chaturvedi, Rajnish Kumar

    2017-02-19

    Peroxisome proliferator-activated receptors (PPARs) are nuclear receptors and they serve to be a promising therapeutic target for several neurodegenerative disorders, which includes Parkinson disease, Alzheimer's disease, Huntington disease and Amyotrophic Lateral Sclerosis. PPARs play an important role in the downregulation of mitochondrial dysfunction, proteasomal dysfunction, oxidative stress, and neuroinflammation, which are the major causes of the pathogenesis of neurodegenerative disorders. In this review, we discuss about the role of PPARs as therapeutic targets in neurodegenerative disorders. Several experimental approaches suggest potential application of PPAR agonist as well as antagonist in the treatment of neurodegenerative disorders. Several epidemiological studies found that the regular usage of PPAR activating non-steroidal anti-inflammatory drugs is effective in decreasing the progression of neurodegenerative diseases including PD and AD. We also reviewed the neuroprotective effects of PPAR agonists and associated mechanism of action in several neurodegenerative disorders both in vitro as well as in vivo animal models. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. Targeting c-kit receptor in neuroblastomas and colorectal cancers using stem cell factor (SCF)-based recombinant bacterial toxins.

    Science.gov (United States)

    Choudhary, Swati; Pardo, Alessa; Rosinke, Reinhard; Batra, Janendra K; Barth, Stefan; Verma, Rama S

    2016-01-01

    Autocrine activation of c-kit (KIT receptor tyrosine kinase) has been postulated to be a potent oncogenic driver in small cell lung cancer, neuroblastoma (NB), and poorly differentiated colorectal carcinoma (CRC). Although targeted therapy involving tyrosine kinase inhibitors (TKIs) such as imatinib mesylate is highly effective for gastrointestinal stromal tumor carrying V560G c-kit mutation, it does not show much potential for targeting wild-type KIT (WT-KIT). Our study demonstrates the role of stem cell factor (SCF)-based toxin conjugates for targeting WT-KIT-overexpressing malignancies such as NBs and CRCs. We constructed SCF-based recombinant bacterial toxins by genetically fusing mutated form of natural ligand SCF to receptor binding deficient forms of Diphtheria toxin (DT) or Pseudomonas exotoxin A (ETA') and evaluated their efficacy in vitro. Efficient targeting was achieved in all receptor-positive neuroblastoma (IMR-32 and SHSY5Y) and colon cancer cell lines (COLO 320DM, HCT 116, and DLD-1) but not in receptor-negative breast carcinoma cell line (MCF-7) thereby proving specificity. While dose- and time-dependent cytotoxicity was observed in both neuroblastoma cell lines, COLO 320DM and HCT 116 cells, only an anti-proliferative effect was observed in DLD-1 cells. We prove that these novel targeting agents have promising potential as KIT receptor tyrosine kinase targeting system.

  10. Targeting Extracellular Domains D4 and D7 of Vascular Endothelial Growth Factor Receptor 2 Reveals Allosteric Receptor Regulatory Sites

    OpenAIRE

    Hyde, Caroline A. C.; Giese, Alexandra; Stuttfeld, Edward; Abram Saliba, Johan; Villemagne, Denis; Schleier, Thomas; Binz, H. Kaspar; Ballmer-Hofer, Kurt

    2012-01-01

    Vascular endothelial growth factors (VEGFs) activate three receptor tyrosine kinases, VEGFR-1, -2, and -3, which regulate angiogenic and lymphangiogenic signaling. VEGFR-2 is the most prominent receptor in angiogenic signaling by VEGF ligands. The extracellular part of VEGF receptors consists of seven immunoglobulin homology domains (Ig domains). Earlier studies showed that domains 2 and 3 (D23) mediate ligand binding, while structural analysis of dimeric ligand/receptor complexes by electron...

  11. RNA nanoparticles harboring annexin A2 aptamer can target ovarian cancer for tumor-specific doxorubicin delivery.

    Science.gov (United States)

    Pi, Fengmei; Zhang, Hui; Li, Hui; Thiviyanathan, Varatharasa; Gorenstein, David G; Sood, Anil K; Guo, Peixuan

    2017-04-01

    A novel modified nucleic acid nanoparticle harboring an annexin A2 aptamer for ovarian cancer cell targeting and a GC rich sequence for doxorubicin loading is designed and constructed. The system utilizes a highly stable three-way junction (3WJ) motif from phi29 packaging RNA as a core structure. A phosphorothioate-modified DNA aptamer targeting annexin A2, Endo28, was conjugated to one arm of the 3WJ. The pRNA-3WJ motif retains correct folding of attached aptamer, keeping its functions intact. It is of significant utility for aptamer-mediated targeted delivery. The DNA/RNA hybrid nanoparticles remained intact after systemic injection in mice and strongly bound to tumors with little accumulation in healthy organs 6 h post-injection. The Endo28-3WJ-Sph1/Dox intercalates selectively enhanced toxicity to annexin A2 positive ovarian cancer cells in vitro. The constructed RNA/DNA hybrid nanoparticles can potentially enhance the therapeutic efficiency of doxorubicin at low doses for ovarian cancer treatment through annexin A2 targeted drug delivery. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. Synthesis and evaluation of ligand targeting the somatostatin receptor for drug delivery to tumor cell

    Energy Technology Data Exchange (ETDEWEB)

    Lee, So Young; Hong, Young Don; Jung, Sung Hee; Choi, Sun Ju [Radioisotope Research Division, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-12-15

    Most of targeted therapies block the action of certain enzymes, proteins, or other molecules involved in the growth and spread of cancer cells to produce its cytotoxic effect. Either small molecule drugs or monoclonal antibodies are mostly used in targeted therapies. Unfortunately, targeted therapy has a certain degree of unwanted side effect like other cytotoxicity inducing chemotherapies. To overcome and to reduce unwanted side effects during a cancer therapy, recently radiopeptide therapies has got the worlds' attraction for the tumor targeting modalities due to its beneficial effect on less side effect compared to cytotoxic chemotherapies. Among radiopeptide therapies, {sup 177}Lu-DOTATATE is a major modality as an effective one invented so far in treating neuroendocrine tumor (NET) and it has been in clinical trials at least one decade. Although it does have rather effective therapeutic effect on NET, it has less effective in rather large solid tumor. There are many ways to improve or increase therapeutic effect of radiopeptide are a finding the potent small molecules to target the tumor site selectively, or a labeling with radioisotope of emitting high energy, or an improving its biological half-life by introducing different moieties to increase lipophilicity. Present study was focus to increase a biological halflife of radio somatostatin which will target the somatostatin receptor by altering the bifunctional chelator (BFCA) by introducing lipophilic moiety to the somatostatin, which would make the labeled peptide stay longer in the tumor site and thus it can intensify the therapeutic effect on tumor cell itself and around tissues.

  13. Lysophosphatidic acid receptors (LPARs): Potential targets for the treatment of neuropathic pain.

    Science.gov (United States)

    Velasco, María; O'Sullivan, Catherine; Sheridan, Graham K

    2017-02-01

    Neuropathic pain can arise from lesions to peripheral or central nerve fibres leading to spontaneous action potential generation and a lowering of the nociceptive threshold. Clinically, neuropathic pain can manifest in many chronic disease states such as cancer, diabetes or multiple sclerosis (MS). The bioactive lipid, lysophosphatidic acid (LPA), via activation of its receptors (LPARs), is thought to play a central role in both triggering and maintaining neuropathic pain. In particular, following an acute nerve injury, the excitatory neurotransmitters glutamate and substance P are released from primary afferent neurons leading to upregulated synthesis of lysophosphatidylcholine (LPC), the precursor for LPA production. LPC is converted to LPA by autotaxin (ATX), which can then activate macrophages/microglia and modulate neuronal functioning. A ubiquitous feature of animal models of neuropathic pain is demyelination of damaged nerves. It is thought that LPA contributes to demyelination through several different mechanisms. Firstly, high levels of LPA are produced following macrophage/microglial activation that triggers a self-sustaining feed-forward loop of de novo LPA synthesis. Secondly, macrophage/microglial activation contributes to inflammation-mediated demyelination of axons, thus initiating neuropathic pain. Therefore, targeting LPA production and/or the family of LPA-activated G protein-coupled receptors (GPCRs) may prove to be fruitful clinical approaches to treating demyelination and the accompanying neuropathic pain. This review discusses our current understanding of the role of LPA/LPAR signalling in the initiation of neuropathic pain and suggests potential targeted strategies for its treatment. This article is part of the Special Issue entitled 'Lipid Sensing G Protein-Coupled Receptors in the CNS'. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Synthesis and Preliminary Evaluation of a 2-Oxoquinoline Carboxylic Acid Derivative for PET Imaging the Cannabinoid Type 2 Receptor

    Directory of Open Access Journals (Sweden)

    Linjing Mu

    2014-03-01

    Full Text Available Cannabinoid receptor subtype 2 (CB2 has been shown to be up-regulated in activated microglia and therefore plays an important role in neuroinflammatory and neurodegenerative diseases such as multiple sclerosis, amyotrophic lateral sclerosis and Alzheimer’s disease. The CB2 receptor is therefore considered as a very promising target for therapeutic approaches as well as for imaging. A promising 2-oxoquinoline derivative designated KP23 was synthesized and radiolabeled and its potential as a ligand for PET imaging the CB2 receptor was evaluated. [11C]KP23 was obtained in 10%–25% radiochemical yield (decay corrected and 99% radiochemical purity. It showed high stability in phosphate buffer, rat and mouse plasma. In vitro autoradiography of rat and mouse spleen slices, as spleen expresses a high physiological expression of CB2 receptors, demonstrated that [11C]KP23 exhibits specific binding towards CB2. High spleen uptake of [11C]KP23 was observed in dynamic in vivo PET studies with Wistar rats. In conclusion, [11C]KP23 showed promising in vitro and in vivo characteristics. Further evaluation with diseased animal model which has higher CB2 expression levels in the brain is warranted.

  15. Targeting colorectal cancer via its microenvironment by inhibiting IGF-1 Receptor-insulin receptor substrate and STAT3 signaling

    Science.gov (United States)

    Sanchez-Lopez, Elsa; Flashner-Abramson, Efrat; Shalapour, Shabnam; Zhong, Zhenyu; Taniguchi, Koji; Levitzki, Alexander; Karin, Michael

    2015-01-01

    The tumor microenvironment (TME) exerts critical pro-tumorigenic effects through cytokines and growth factors that support cancer cell proliferation, survival, motility and invasion. Insulin-like growth factor-1 (IGF-1) and Signal transducer and activator of transcription 3 (STAT3) stimulate colorectal cancer (CRC) development and progression via cell autonomous and microenvironmental effects. Using a unique inhibitor, NT157, which targets both IGF-1 receptor (IGF-1R) and STAT3, we show that these pathways regulate many TME functions associated with sporadic colonic tumorigenesis in CPC-APC mice, in which cancer development is driven by loss of the Apc tumor suppressor gene. NT157 causes a substantial reduction in tumor burden by affecting cancer cells, cancer-associated fibroblasts (CAF) and myeloid cells. Decreased cancer cell proliferation and increased apoptosis were accompanied by inhibition of CAF activation and decreased inflammation. Furthermore, NT157 inhibited expression of pro-tumorigenic cytokines, chemokines and growth factors, including IL-6, IL-11 and IL-23 as well as CCL2, CCL5, CXCL7, CXCL5, ICAM1 and TGFβ; decreased cancer cell migratory activity and reduced their proliferation in the liver. NT157 represents a new class of anti-cancer drugs that affect both the malignant cell and its supportive microenvironment. PMID:26364612

  16. Promotion of Wound Healing by an Agonist of Adenosine A2A Receptor Is Dependent on Tissue Plasminogen Activator.

    Science.gov (United States)

    Montesinos, M Carmen; Desai-Merchant, Avani; Cronstein, Bruce N

    2015-12-01

    Impaired wound healing, as it occurs in diabetes mellitus or long-term corticoid treatment, is commonly associated with disability, diminished quality of life, and high economic costs. Selective agonists of the A2A receptor subtype of adenosine, an endogenous regulator of inflammation, promote tissue repair in animal models, both healthy and with impaired healing. Plasmin-mediated proteolysis of fibrin and other matrix proteins is essential for cell migration at sites of injury. Since adenosine A2A receptor activation increases plasminogen activator release from macrophages and mast cells, we studied the effect of a selective agonist, CGS-21680, on full-thickness excisional wound closure in wild-type, urokinase plasminogen activator (uPA)-deficient, and tissue plasminogen activator (tPA)-deficient mice. Wound closure was impaired in tPA- and uPA-deficient mice as compared with wild-type mice, and topical application of CGS-21680 significantly increased the rate at which wounds closed in wild-type mice and uPA-deficient mice, but not in tPA-deficient mice. Immunostaining of tissue sections showed that tPA was present in endothelial cells and histiocytes by day 3 post-wound and also by day 6. In contrast, uPA was more prominent in these cell types only by day 6 post-wound. Our results confirm that plasminogen activation contributes to wound repair and are consistent with the hypothesis that adenosine A2A receptor activation promotes wound closure by a mechanism that depends upon tPA, but not uPA. Moreover, our results suggest that topical adenosine A2A receptor agonists may be useful in promotion of wound closure in patients with impaired wound healing.

  17. ALTERED EXPRESSION AND FUNCTIONALITY OF A2A ADENOSINE RECEPTORS IN HUNTINGTON’S DISEASE AND OTHER POLYGLUTAMINE DISORDERS

    OpenAIRE

    Vincenzi, Fabrizio

    2009-01-01

    Several studies have suggested the possible involvement of A2A adenosine receptors in the pathogenesis of neuronal disorders, including Huntington’s disease. Huntington’s disease is an inherited neurodegenerative disease clinically characterized by motor, cognitive and behavioural impairments. The genetic cause of the disease is the expanded CAG triplet in a gene coding for huntingtin, a protein involved in several physiological processes. Huntington’s disease affects primarly ...

  18. Thermodynamics and structural analysis of positive allosteric modulation of the ionotropic glutamate receptor GluA2

    DEFF Research Database (Denmark)

    Krintel, Christian; Frydenvang, Karla; Olsen, Lars;

    2012-01-01

    Positive allosteric modulators of the ionotropic glutamate receptor-2 (GluA2) are promising compounds for the treatment of cognitive disorders, e.g. Alzheimer's disease. These modulators bind within the dimer interface of the ligand-binding domain and stabilize the agonist-bound conformation slow...... by the ethyl substituent of BPAM-97. These results add important information on binding affinities and thermodynamic details, and provide a new tool in development of drugs against cognitive disorders....

  19. Adenosine A2A receptors and uric acid mediate protective effects of inosine against TNBS-induced colitis in rats.

    Science.gov (United States)

    Rahimian, Reza; Fakhfouri, Gohar; Daneshmand, Ali; Mohammadi, Hamed; Bahremand, Arash; Rasouli, Mohammad Reza; Mousavizadeh, Kazem; Dehpour, Ahmad Reza

    2010-12-15

    Inflammatory bowel disease comprises chronic recurrent inflammation of gastrointestinal tract. This study was conducted to investigate inosine, a potent immunomodulator, in 2,4,6-trinitrobenzene sulphonic acid (TNBS)-induced chronic model of experimental colitis, and contribution of adenosine A(2A) receptors and the metabolite uric acid as possible underlying mechanisms. Experimental colitis was rendered in rats by a single colonic administration of 10 mg of TNBS. Inosine, potassium oxonate (a hepatic uricase inhibitor), SCH-442416 (a selective adenosine A(2A) receptor antagonist), inosine+potassium oxonate, or inosine+SCH-442416 were given twice daily for 7 successive days. At the end of experiment, macroscopic and histopathologic scores, colonic malondialdehyde (MDA), Tumor Necrosis Factor-alpha (TNF-α) and Interleukin-1beta (IL-1β) levels, and myeloperoxidase (MPO) activity were assessed. Plasma uric acid level was measured throughout the experiment. Both macroscopic and histological features of colonic injury were markedly ameliorated by either inosine, oxonate or inosine+oxonate. Likewise, the elevated amounts of MPO and MDA abated as well as those of TNF-α and IL-1β (Pacid levels were significantly higher in inosine or oxonate groups compared to control. Inosine+oxonate resulted in an even more elvelated uric acid level than each treatment alone (Pacid and adenosine A(2A) receptors contribute to these salutary properties.

  20. Targeting androgen receptor/Src complex impairs the aggressive phenotype of human fibrosarcoma cells.

    Science.gov (United States)

    Castoria, Gabriella; Giovannelli, Pia; Di Donato, Marzia; Hayashi, Ryo; Arra, Claudio; Appella, Ettore; Auricchio, Ferdinando; Migliaccio, Antimo

    2013-01-01

    Hormones and growth factors influence the proliferation and invasiveness of human mesenchymal tumors. The highly aggressive human fibrosarcoma HT1080 cell line harbors classical androgen receptor (AR) that responds to androgens triggering cell migration in the absence of significant mitogenesis. As occurs in many human cancer cells, HT1080 cells also express epidermal growth factor receptor (EGFR). We report that the pure anti-androgen Casodex inhibits the growth of HT1080 cell xenografts in immune-depressed mice, revealing a novel role of AR in fibrosarcoma progression. In HT1080 cultured cells EGF, but not androgens, robustly increases DNA synthesis. Casodex abolishes the EGF mitogenic effect, implying a crosstalk between EGFR and AR. The mechanism underlying this crosstalk has been analyzed using an AR-derived small peptide, S1, which prevents AR/Src tyrosine kinase association and androgen-dependent Src activation. Present findings show that in HT1080 cells EGF induces AR/Src Association, and the S1 peptide abolishes both the assembly of this complex and Src activation. The S1 peptide inhibits EGF-stimulated DNA synthesis, cell matrix metalloproteinase-9 (MMP-9) secretion and invasiveness of HT1080 cells. Both Casodex and S1 peptide also prevent DNA synthesis and migration triggered by EGF in various human cancer-derived cells (prostate, breast, colon and pancreas) that express AR. This study shows that targeting the AR domain involved in AR/Src association impairs EGF signaling in human fibrosarcoma HT1080 cells. The EGF-elicited processes inhibited by the peptide (DNA synthesis, MMP-9 secretion and invasiveness) cooperate in increasing the aggressive phenotype of HT1080 cells. Therefore, AR represents a new potential therapeutic target in human fibrosarcoma, as supported by Casodex inhibition of HT1080 cell xenografts. The extension of these findings in various human cancer-derived cell lines highlights the conservation of this process across divergent cancer