RESUMO
AIMS: We report on investigations exploring the P2X3-receptor antagonist filapixant's effect on taste perception and cough-reflex sensitivity and describe its pharmacokinetics, including its CYP3A4-interaction potential. METHODS: In a randomized, placebo-controlled, double-blind study, 3 × 12 healthy men (18-45 years) were assigned (3:1) to filapixant (20, 80 or 250 mg by mouth) or placebo twice daily over 2 weeks. A single dose of midazolam (1 mg), a CYP3A4 substrate, was administered with and without filapixant. Assessments included a taste-strips test, a taste questionnaire, cough challenge with adenosine triphosphate, adverse event reports and standard safety assessments. RESULTS: Taste disturbances were observed mainly in the 250-mg group: six of nine participants (67%) in this group reported hypo- or dysgeusia in the questionnaire; eight participants (89%) reported taste-related adverse events. Five participants (56%) had a decrease in overall taste-strips-test scores ≥2 points (point estimate -1.1 points, 90% confidence interval [-3.3; 1.1]). Cough counts increased with adenosine triphosphate concentration but without major differences between treatments. Filapixant exposure increased proportionally to dose. Co-administration of filapixant had no clinically relevant effect on midazolam pharmacokinetics. Area under the concentration-time curve ratios and 90% confidence intervals were within 80-125%. No serious or severe adverse events were reported. CONCLUSIONS: Overall, filapixant was safe and well tolerated, apart from mild, transient taste disturbances. Such disturbances occurred more frequently than expected based on (in vitro) receptor-selectivity data, suggesting that other factors than P2X3:P2X2/3 selectivity might also play an important role in this context. The cough-challenge test showed no clear treatment effect. Filapixant has no clinically relevant CYP3A4 interaction potential.
Assuntos
Citocromo P-450 CYP3A , Relação Dose-Resposta a Droga , Interações Medicamentosas , Midazolam , Antagonistas do Receptor Purinérgico P2X , Humanos , Masculino , Adulto , Citocromo P-450 CYP3A/metabolismo , Antagonistas do Receptor Purinérgico P2X/administração & dosagem , Antagonistas do Receptor Purinérgico P2X/farmacocinética , Antagonistas do Receptor Purinérgico P2X/efeitos adversos , Antagonistas do Receptor Purinérgico P2X/farmacologia , Método Duplo-Cego , Adulto Jovem , Midazolam/farmacocinética , Midazolam/administração & dosagem , Midazolam/efeitos adversos , Adolescente , Voluntários Saudáveis , Pessoa de Meia-Idade , Tosse/induzido quimicamente , Paladar/efeitos dos fármacos , Receptores Purinérgicos P2X3/efeitos dos fármacos , Receptores Purinérgicos P2X3/metabolismoRESUMO
Hyperinflammation plays an important role in severe and critical COVID-19. Using inconsistent criteria, many researchers define hyperinflammation as a form of very severe inflammation with cytokine storm. Therefore, COVID-19 patients are treated with anti-inflammatory drugs. These drugs appear to be less efficacious than expected and are sometimes accompanied by serious adverse effects. SARS-CoV-2 promotes cellular ATP release. Increased levels of extracellular ATP activate the purinergic receptors of the immune cells initiating the physiologic pro-inflammatory immune response. Persisting viral infection drives the ATP release even further leading to the activation of the P2X7 purinergic receptors (P2X7Rs) and a severe yet physiologic inflammation. Disease progression promotes prolonged vigorous activation of the P2X7R causing cell death and uncontrolled ATP release leading to cytokine storm and desensitisation of all other purinergic receptors of the immune cells. This results in immune paralysis with co-infections or secondary infections. We refer to this pathologic condition as hyperinflammation. The readily available and affordable P2X7R antagonist lidocaine can abrogate hyperinflammation and restore the normal immune function. The issue is that the half-maximal effective concentration for P2X7R inhibition of lidocaine is much higher than the maximal tolerable plasma concentration where adverse effects start to develop. To overcome this, we selectively inhibit the P2X7Rs of the immune cells of the lymphatic system inducing clonal expansion of Tregs in local lymph nodes. Subsequently, these Tregs migrate throughout the body exerting anti-inflammatory activities suppressing systemic and (distant) local hyperinflammation. We illustrate this with six critically ill COVID-19 patients treated with lidocaine.
Assuntos
Trifosfato de Adenosina/metabolismo , COVID-19/imunologia , Síndrome da Liberação de Citocina/etiologia , Inflamação/etiologia , Lidocaína/uso terapêutico , Antagonistas do Receptor Purinérgico P2X/uso terapêutico , Receptores Purinérgicos/fisiologia , Anti-Inflamatórios/uso terapêutico , Cuidados Críticos , Síndrome da Liberação de Citocina/tratamento farmacológico , Humanos , Inflamação/tratamento farmacológico , Infusões Subcutâneas , Lidocaína/administração & dosagem , Lidocaína/farmacologia , Linfonodos/imunologia , Sistema Linfático/imunologia , Masculino , Dose Máxima Tolerável , Pessoa de Meia-Idade , Modelos Imunológicos , Antagonistas do Receptor Purinérgico P2X/administração & dosagem , Antagonistas do Receptor Purinérgico P2X/farmacologia , Receptores Purinérgicos/efeitos dos fármacos , Receptores Purinérgicos P1/efeitos dos fármacos , Receptores Purinérgicos P1/fisiologia , Receptores Purinérgicos P2X7/fisiologia , Síndrome do Desconforto Respiratório/tratamento farmacológico , Síndrome do Desconforto Respiratório/etiologia , Transdução de Sinais , Linfócitos T Reguladores/imunologiaRESUMO
P2X7 receptor promotes inflammatory response and neuropathic pain. New drugs capable of impairing inflammation and pain-reducing adverse effects extracted from plant extracts have been studied. Physalis angulate L. possesses traditional uses and exhibits antiparasitic, anti-inflammatory, antimicrobial, antinociceptive, antimalarial, antileishmanial, immunosuppressive, antiasthmatic. diuretic, and antitumor activities. The most representative phytochemical constituents identified with medicinal importance are the physalins and withanolides. However, the mechanism of anti-inflammatory action is scarce. Although some physalins and withanolides subtypes have anti-inflammatory activity, only four physalins subtypes (B, D, F, and G) have further studies. Therefore, we evaluated the crude ethanolic extract enriched with physalins B, D, F, and G from P. angulata leaves, a pool containing the physalins B, D, F, G, and the physalins individually, as P2X7 receptor antagonists. For this purpose, we evaluated ATP-induced dye uptake, macroscopic currents, and interleukin 1-ß (IL-1ß) in vitro. The crude extract and pool dose-dependently inhibited P2X7 receptor function. Thus, physalin B, D, F, and G individually evaluated for 5'-triphosphate (ATP)-induced dye uptake assay, whole-cell patch-clamp, and cytokine release showed distinct antagonist levels. Physalin D displayed higher potency and efficacy than physalin B, F, and G for all these parameters. In vivo mice model as ATP-induced paw edema was potently inhibited for physalin D, in contrast to physalin B, F, and G. ATP and lipopolysaccharide (LPS)-induced pleurisy in mice were reversed for physalin D treatment. Molecular modeling and computational simulation predicted the intermolecular interactions between the P2X7 receptor and physalin derivatives. In silico results indicated physalin D and F as a potent allosteric P2X7 receptor antagonist. These data confirm physalin D as a promisor source for developing a new P2X7 receptor antagonist with anti-inflammatory action.
Assuntos
Lesão Pulmonar Aguda/tratamento farmacológico , Physalis/química , Extratos Vegetais/farmacologia , Secoesteroides/farmacologia , Lesão Pulmonar Aguda/fisiopatologia , Animais , Anti-Inflamatórios/administração & dosagem , Anti-Inflamatórios/isolamento & purificação , Anti-Inflamatórios/farmacologia , Simulação por Computador , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Células HEK293 , Humanos , Masculino , Camundongos , Modelos Moleculares , Extratos Vegetais/administração & dosagem , Folhas de Planta , Antagonistas do Receptor Purinérgico P2X/administração & dosagem , Antagonistas do Receptor Purinérgico P2X/isolamento & purificação , Antagonistas do Receptor Purinérgico P2X/farmacologia , Receptores Purinérgicos P2X7/efeitos dos fármacos , Secoesteroides/isolamento & purificaçãoRESUMO
For the past three decades, our laboratory has conducted pioneering research to elucidate the complexity of purinergic signaling in the CNS, alone and in collaboration with other groups, inspired by the ground-breaking efforts of Geoffrey Burnstock. This review summarizes our contribution to understand the nucleotide receptor signaling in the CNS with a special focus on the P2X7 receptor.
Assuntos
Sistema Nervoso Central/metabolismo , Doenças Neurodegenerativas/metabolismo , Receptores Purinérgicos P2X7/metabolismo , Trifosfato de Adenosina/metabolismo , Animais , Sinalização do Cálcio/efeitos dos fármacos , Sinalização do Cálcio/fisiologia , Sistema Nervoso Central/efeitos dos fármacos , Humanos , Doenças Neurodegenerativas/tratamento farmacológico , Agonistas do Receptor Purinérgico P2X/administração & dosagem , Antagonistas do Receptor Purinérgico P2X/administração & dosagem , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologiaRESUMO
Graft-versus-host disease (GVHD) is a severe inflammatory response arising from allogeneic haematopoietic stem cell transplantation. Previous studies revealed that antagonism of the P2X7 receptor with Brilliant Blue G (BBG) reduced liver GVHD but did not alter clinical GVHD in a humanised mouse model. Therefore, the present study aimed to trial a modified injection regime using more frequent dosing of BBG to improve outcomes in this model of GVHD. NOD-scid IL2Rγnull (NSG) mice were injected intraperitoneally (i.p.) with 10 × 106 human peripheral blood mononuclear cells (hPBMCs) (day 0), then daily with BBG (50 mg/kg) or saline (days 0-10). BBG significantly reduced clinical score, mortality and histological GVHD compared with saline treatment (endpoint). BBG significantly increased proportions of human regulatory T cells (Tregs) and human B cells and reduced serum human interferon-γ compared with saline treatment prior to development of clinical GVHD (day 21). To confirm the therapeutic benefit of P2X7 antagonism, NSG mice were injected i.p. with 10 × 106 hPBMCs (day 0), then daily with pyridoxalphosphate-6-azophenyl-2',4'-disulfonic acid (PPADS) (300 mg/kg) or saline (days 0-10). PPADS increased human Treg proportions compared with saline treatment (day 21), but potential clinical benefits were confounded by increased weight loss with this antagonist. To investigate the role of P2X7 antagonism on Treg survival, hPBMCs were cultured in reduced serum conditions to promote cell death. BBG increased proportions of Tregs (and B cells) compared with saline under these conditions. In conclusion, P2X7 antagonism reduces clinical and histological GVHD in a humanised mouse model corresponding to an increase in human Tregs.
Assuntos
Doença Enxerto-Hospedeiro/tratamento farmacológico , Antagonistas do Receptor Purinérgico P2X/farmacologia , Receptores Purinérgicos P2X7/efeitos dos fármacos , Corantes de Rosanilina/farmacologia , Adulto , Animais , Linfócitos B , Modelos Animais de Doenças , Feminino , Doença Enxerto-Hospedeiro/patologia , Transplante de Células-Tronco Hematopoéticas , Humanos , Leucócitos Mononucleares , Masculino , Camundongos Endogâmicos NOD , Camundongos SCID , Antagonistas do Receptor Purinérgico P2X/administração & dosagem , Fosfato de Piridoxal/administração & dosagem , Fosfato de Piridoxal/análogos & derivados , Fosfato de Piridoxal/farmacologia , Corantes de Rosanilina/administração & dosagem , Linfócitos T Reguladores/efeitos dos fármacosRESUMO
Extracellular purine and pyrimidine nucleotides produce their pharmacological effects through P2 receptors. These were first named by Geoff Burnstock in an extensive review in 1978. They were then subdivided into P2X and P2Y purinoceptors by Burnstock and Kennedy in 1985, based on applying pharmacological criteria to data generated by functional studies in smooth muscle tissues. Several other P2 subtypes, P2T, P2Z, P2U and P2D were subsequently identified in the following years, again using pharmacological criteria. The number and identity of subtypes were clarified and simplified by the cloning of seven ATP-sensitive ligand-gated ion channel subunits and eight adenine and/or uracil nucleotide-sensitive G protein-coupled receptors from 1993 onwards. The former were all classified as members of the P2X receptor family and the latter as members of the P2Y receptor family. More recently, high resolution imaging of the tertiary and quaternary structures of several P2X and P2Y receptor subtypes has provided a much greater understanding of how and where agonists and antagonists bind to the receptors and how this leads to changes in receptor conformation and activity. In addition, medicinal chemistry has produced a variety of subtype-selective agonists and antagonists, some of which are now in clinical use. This progress and success is a testimony to the foresight, intelligence, enthusiasm and drive of Geoff Burnstock, who led the field forward throughout his scientific life.
Assuntos
Trifosfato de Adenosina/metabolismo , Receptores Purinérgicos P2X/metabolismo , Receptores Purinérgicos P2Y/metabolismo , Transdução de Sinais/fisiologia , Animais , Humanos , Agonistas do Receptor Purinérgico P2X/administração & dosagem , Antagonistas do Receptor Purinérgico P2X/administração & dosagem , Agonistas do Receptor Purinérgico P2Y , Antagonistas do Receptor Purinérgico P2Y/administração & dosagem , Transdução de Sinais/efeitos dos fármacosRESUMO
Chronic pain is a debilitating condition that often occurs following peripheral tissue inflammation and nerve injury. This pain, especially neuropathic pain, is a significant clinical problem because of the ineffectiveness of clinically available drugs. Since Burnstock proposed new roles of nucleotides as neurotransmitters, the roles of extracellular ATP and P2 receptors (P2Rs) in pain signaling have been extensively studied, and ATP-P2R signaling has subsequently received much attention as it can provide clues toward elucidating the mechanisms underlying chronic pain and serve as a potential therapeutic target. This review summarizes the literature regarding the role of ATP signaling via P2X3Rs (as well as P2X2/3Rs) in primary afferent neurons and via P2X4Rs and P2X7Rs in spinal cord microglia in chronic pain, and discusses their respective therapeutic potentials.
Assuntos
Dor Crônica/metabolismo , Nociceptividade/fisiologia , Receptores Purinérgicos P2X3/metabolismo , Receptores Purinérgicos P2X4/metabolismo , Receptores Purinérgicos P2X7/metabolismo , Transdução de Sinais/fisiologia , Trifosfato de Adenosina/metabolismo , Animais , Dor Crônica/tratamento farmacológico , Humanos , Nociceptividade/efeitos dos fármacos , Agonistas do Receptor Purinérgico P2X/administração & dosagem , Antagonistas do Receptor Purinérgico P2X/administração & dosagem , Células Receptoras Sensoriais/efeitos dos fármacos , Células Receptoras Sensoriais/metabolismo , Transdução de Sinais/efeitos dos fármacos , Medula Espinal/efeitos dos fármacos , Medula Espinal/metabolismoRESUMO
It is increasingly appreciated that ion channels have a crucial role in tumors, either as promoters of cancer cell growth, or modulators of immune cell functions, or both. Among ion channels, P2X receptors have a special status because they are gated by ATP, a common and abundant component of the tumor microenvironment. Furthermore, one P2X receptor, i.e. P2X7, may also function as a conduit for ATP release, thus fuelling the increased extracellular ATP level in the tumor interstitium. These findings show that P2X receptors and extracellular ATP are indissoluble partners and key regulators of tumor growth, and suggest the exploitation of the extracellular ATP-P2X partnership to develop innovative therapeutic approaches to cancer.
Assuntos
Progressão da Doença , Neoplasias/metabolismo , Receptores Purinérgicos P2X/metabolismo , Microambiente Tumoral/fisiologia , Trifosfato de Adenosina/imunologia , Trifosfato de Adenosina/metabolismo , Animais , Humanos , Neoplasias/tratamento farmacológico , Neoplasias/imunologia , Agonistas do Receptor Purinérgico P2X/administração & dosagem , Antagonistas do Receptor Purinérgico P2X/administração & dosagem , Receptores Purinérgicos P2X/imunologia , Microambiente Tumoral/efeitos dos fármacosRESUMO
Adenosine triphosphate (ATP) is a molecule that on one hand plays a central role in cellular energetics and which on the other is a ubiquitous signaling molecule when released into the extracellular media. Extracellular ATP accumulates in inflammatory environments where it acts as a damage-associated molecular pattern and activates the purinergic P2X receptor 7 (P2X7) in immune cells. P2X7 receptor activation induces the formation of the nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing 3 (NLRP3) inflammasome and the activation of the inflammatory caspase-1. Caspase-1 causes an inflammatory type of cell death called pyroptosis through the release of pro-inflammatory cytokines and intracellular content. Consequently, intense research efforts have been devoted to the design of novel anti-inflammatory therapies, focusing in particular on the P2X7 receptor and the NLRP3 pathway and the introduction of new blocking molecules in early phase clinical trials.
Assuntos
Trifosfato de Adenosina/metabolismo , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Receptores Purinérgicos P2X7/metabolismo , Animais , Humanos , Inflamação/tratamento farmacológico , Inflamação/metabolismo , Proteína 3 que Contém Domínio de Pirina da Família NLR/antagonistas & inibidores , Agonistas do Receptor Purinérgico P2X/administração & dosagem , Antagonistas do Receptor Purinérgico P2X/administração & dosagem , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologiaRESUMO
Current therapies for the treatment of chronic pain provide inadequate relief for millions of suffering patients, demonstrating the need for better therapies that will treat pain effectively and improve the quality of patient's lives. Better understanding of the mechanisms that mediate chronic pain is critical for developing drugs with improved clinical outcomes. Adenosine triphosphate (ATP) is a key modulator in nociceptive pathways. Release of ATP from injured tissue or sympathetic efferents has sensitizing effects on sensory neurons in the periphery, and presynaptic vesicular release of ATP from the central terminals can increase glutamate release thereby potentiating downstream central sensitization mechanisms, a condition thought to underlie many chronic pain conditions. The purinergic receptors on sensory nerves primarily responsible for ATP signaling are P2X3 and P2X2/3. Selective knockdown experiments, or inhibition with small molecules, demonstrate P2X3-containing receptors are key targets to modulate nociceptive signals. Preclinical studies have identified that P2X3-containing receptors are critical for sensory transduction for bladder function, and clinical studies have shown promise in treatment for bladder pain and pain associated with osteoarthritis. Further clinical characterization of antagonists to P2X3-containing receptors may lead to improved therapies in the treatment of chronic pain.
Assuntos
Dor Crônica/tratamento farmacológico , Dor Crônica/metabolismo , Sistemas de Liberação de Medicamentos/métodos , Antagonistas do Receptor Purinérgico P2X/metabolismo , Receptores Purinérgicos P2X3/metabolismo , Trifosfato de Adenosina/antagonistas & inibidores , Trifosfato de Adenosina/metabolismo , Animais , Humanos , Antagonistas do Receptor Purinérgico P2X/administração & dosagem , Células Receptoras Sensoriais/efeitos dos fármacos , Células Receptoras Sensoriais/metabolismo , Resultado do TratamentoRESUMO
BACKGROUND: This is the first report of the pharmacodynamic (PD) effects of the selective, potent and brain-penetrant P2X7 receptor (P2X7R) antagonist JNJ-54175446. Activation of the P2X7R, an adenosine triphosphate-gated ion channel, leads to the production of pro-inflammatory cytokines, which have been linked to neuroinflammation and play a role in the pathogenesis of mood disorders. Previous clinical studies with JNJ-54175446 demonstrated peripheral target engagement of JNJ-54175446 by assessing ex vivo lipopolysaccharide (LPS)-stimulated cytokine production. Blood-brain barrier penetration and a clear dose-receptor occupancy relationship was demonstrated using positron emission tomography. AIMS: The objectives of this double-blind, placebo-controlled, translational study were to assess the safety and tolerability of administering multiple doses of JNJ-54175446 and to explore its PD effects using a dexamphetamine challenge. METHODS: Subjects (N = 64) were randomised to either JNJ-54175446 (50-450 mg; n = 48) or placebo (n = 16) and underwent a baseline oral 20 mg dexamphetamine challenge followed by 11 consecutive days q.d. dosing with JNJ-54175446/placebo and a randomised crossover dexamphetamine/placebo challenge. RESULTS: At all doses tested, JNJ-54175446 was well tolerated and suppressed the ex vivo LPS-induced release of cytokines. At doses ⩾100 mg, JNJ-54175446 attenuated dexamphetamine-induced increases in locomotion and enhanced the mood-elevating effects of dexamphetamine, suggesting that a dose that is approximately twice as high is needed to obtain a central PD response compared to the dose needed for maximum peripheral occupancy. CONCLUSION: Overall, the observed pharmacological profile of JNJ-54175446 in the dexamphetamine challenge paradigm is compatible with a potential mood-modulating effect.
Assuntos
Estimulantes do Sistema Nervoso Central/farmacologia , Dextroanfetamina/farmacologia , Antagonistas do Receptor Purinérgico P2X/farmacologia , Piridinas/farmacologia , Triazóis/farmacologia , Adolescente , Adulto , Estimulantes do Sistema Nervoso Central/administração & dosagem , Transtorno Depressivo Maior/tratamento farmacológico , Dextroanfetamina/administração & dosagem , Método Duplo-Cego , Eletroencefalografia , Humanos , Inflamação/tratamento farmacológico , Masculino , Antagonistas do Receptor Purinérgico P2X/administração & dosagem , Antagonistas do Receptor Purinérgico P2X/efeitos adversos , Antagonistas do Receptor Purinérgico P2X/farmacocinética , Piridinas/administração & dosagem , Piridinas/efeitos adversos , Piridinas/farmacocinética , Pesquisa Translacional Biomédica , Triazóis/administração & dosagem , Triazóis/efeitos adversos , Triazóis/farmacocinética , Adulto JovemRESUMO
Neuropathic Pain (NPP) is caused by direct or indirect damage to the nervous system and is a common symptom of many diseases. Clinically, drugs are usually used to suppress pain, such as (lidocaine, morphine, etc.), but the effect is short-lived, poor analgesia, and there are certain dependence and side effects. Therefore, the investigation of the treatment of NPP has become an urgent problem in medical, attracting a lot of research attention. P2X7 is dependent on Adenosine triphosphate (ATP) ion channel receptors and has dual functions for the development of nerve damage and pain. In this review, we explored the link between the P2X7 receptor (P2X7R) and NPP, providing insight into the P2X7R and NPP, discussing the pathological mechanism of P2 X7R in NPP and the biological characteristics of P2X7R antagonist inhibiting its over-expression for the targeted therapy of NPP.
Assuntos
Encéfalo/fisiopatologia , Neuralgia/fisiopatologia , Receptores Purinérgicos P2X7/fisiologia , Trifosfato de Adenosina/fisiologia , Animais , Humanos , Inflamação/fisiopatologia , Microglia/fisiologia , Neuralgia/tratamento farmacológico , Antagonistas do Receptor Purinérgico P2X/administração & dosagem , Transdução de Sinais/efeitos dos fármacosRESUMO
BACKGROUND: P2X7 receptors (P2X7R) are ligand-gated ion channels activated by adenosine 5'-triphosphate (ATP), which are involved in processes that are dysfunctional in stress response and depression, such as neurotransmitter release, and neuroimmune response. Genetic and pharmacological inhibition of the P2X7R induce antidepressant-like effects in animals exposed to stress. However, the effect of P2X7R antagonism in an animal model of depression based on selective breeding has not previously been studied, and the mechanism underling the antidepressant-like effect induced by the P2X7R blockade remains unknown. AIMS: The present study aimed to: (1) determine whether P2X7R blockade induces antidepressant-like effects in the Flinders Sensitive Line (FSL) rats and, (2) investigate whether brain-derived neurotrophic factor (BDNF) signalling in the frontal cortex and hippocampus is involved in this effect. METHODS: FSL and the control Flinders Resistant Line (FRL) rats were treated with vehicle or the P2X7R antagonist A-804598 (3, 10 or 30 mg/Kg/day) for 1 or 7 days before being exposed to the forced swim test (FST). After the behavioural test, animals were decapitated, their brains were removed and the frontal cortex, ventral and dorsal hippocampus were dissected for BDNF signalling analysis. RESULTS: We found that repeated treatment with A-804598 (30 mg/Kg) reduced the immobility time in the FST and activated the BDNF signalling in the ventral hippocampus of FSL rats. CONCLUSIONS: P2X7R blockade induces an antidepressant-like effect associated with increased levels of BDNF-AKT-p70 S6 kinase in the ventral hippocampus, which may be mediated by tropomyosin-related kinase B (TRKB) receptor activation supporting the notion of P2X7R antagonism as a potential new antidepressant strategy.
Assuntos
Antidepressivos/farmacologia , Depressão/tratamento farmacológico , Guanidinas/farmacologia , Antagonistas do Receptor Purinérgico P2X/administração & dosagem , Quinolinas/farmacologia , Animais , Antidepressivos/administração & dosagem , Comportamento Animal/efeitos dos fármacos , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Depressão/fisiopatologia , Modelos Animais de Doenças , Guanidinas/administração & dosagem , Masculino , Dose Máxima Tolerável , Antagonistas do Receptor Purinérgico P2X/farmacologia , Quinolinas/administração & dosagem , Ratos , Receptor trkB/metabolismo , Receptores Purinérgicos P2X7/efeitos dos fármacos , Receptores Purinérgicos P2X7/metabolismo , Estresse Psicológico/tratamento farmacológico , Natação , Fatores de TempoRESUMO
BACKGROUND: Extracellular adenosine 5'-triphosphate (ATP) plays important mechanistic roles in pulmonary disorders in general and chronic obstructive pulmonary disease (COPD) and cough in particular. The effects of ATP in the lungs are mediated to a large extent by P2X2/3 receptors (P2X2/3R) localized on vagal sensory nerve terminals (both C and Aδ fibers). The activation of these receptors by ATP triggers a pulmonary-pulmonary central reflex, which results in bronchoconstriction and cough, and is also proinflammatory due to the release of neuropeptides from these nerve terminals via the axon reflex. These actions of ATP in the lungs constitute a strong rationale for the development of a new class of drugs targeting P2X2/3R. DT-0111 is a novel, small, water-soluble molecule that acts as an antagonist at P2X2/3R sites. METHODS: Experiments using receptor-binding functional assays, rat nodose ganglionic cells, perfused innervated guinea pig lung preparation ex vivo, and anesthetized and conscious guinea pigs in vivo were performed. RESULTS: DT-0111 acted as a selective and effective antagonist at P2X2/3R, that is, it did not activate or block P2YR; markedly inhibited the activation by ATP of nodose pulmonary vagal afferents in vitro; and, given as an aerosol, inhibited aerosolized ATP-induced bronchoconstriction and cough in vivo. CONCLUSIONS: These results indicate that DT-0111 is an attractive drug-candidate for the treatment of COPD and chronic cough, both of which still constitute major unmet clinical needs. The reviews of this paper are available via the supplementary material section.
Assuntos
Tosse/tratamento farmacológico , Pulmão/inervação , Neurônios/efeitos dos fármacos , Gânglio Nodoso/efeitos dos fármacos , Doença Pulmonar Obstrutiva Crônica/tratamento farmacológico , Antagonistas do Receptor Purinérgico P2X/farmacologia , Receptores Purinérgicos P2X2/efeitos dos fármacos , Receptores Purinérgicos P2X3/efeitos dos fármacos , Potenciais de Ação , Trifosfato de Adenosina/metabolismo , Administração por Inalação , Aerossóis , Animais , Broncoconstrição/efeitos dos fármacos , Tosse/metabolismo , Tosse/fisiopatologia , Cobaias , Masculino , Neurônios/metabolismo , Gânglio Nodoso/metabolismo , Gânglio Nodoso/fisiopatologia , Estudo de Prova de Conceito , Doença Pulmonar Obstrutiva Crônica/metabolismo , Doença Pulmonar Obstrutiva Crônica/fisiopatologia , Antagonistas do Receptor Purinérgico P2X/administração & dosagem , Ratos , Receptores Purinérgicos P2X2/metabolismo , Receptores Purinérgicos P2X3/metabolismo , Transdução de SinaisRESUMO
The functional role of P2X7 receptor (P2X7R) inhibition in cancer-induced bone pain has been highly contradictory. Whereas knockout studies have suggested pro-nociceptive effects, pharmacological studies suggest anti-nociceptive or no effect. The discrepancy is likely linked to the highly polymorphic nature of the P2X7R and the related functional differences in different tissue and conditions. In this study we tested the analgesic potential of AFC5261, a selective P2X7R antagonist, in a rat model of cancer-induced bone pain to evaluate if the opposing pro- and anti-nociceptive effects could be a consequence of long vs. short term inhibition of the P2X7R. Following intratibial inoculation of MRMT-1 carcinoma cells, movement-evoked and background pain was assessed with the limb use and weight-bearing test, and the effect of acute and chronic AFC5261-treatement evaluated. Bone degradation and tumor progression was in addition evaluated with x-ray densitometry and bioluminescence, respectively. In an acute treatment regime, a single administration of 300â¯mg/kg AFC5261 had no effect on either weight-bearing or limb use deficits. In contrast, morphine significantly increased both the limb use and weight-bearing ratio. In a chronic treatment study, BID administration of 300â¯mg/kg AFC5261 exacerbated the pain-related behavior, demonstrated by an earlier onset of both limb use and weight-bearing deficits without affecting the overall bone degradation or tumor progression. In contrast, 50â¯mg/kg and 100â¯mg/kg AFC5261 had no effect on the pain-related behavior. Overall, the data suggest that whereas acute P2X7R inhibition has no effect on the pain-related behavior, chronic inhibition exacerbate the cancer-induced bone pain.
Assuntos
Neoplasias Ósseas/complicações , Dor do Câncer/tratamento farmacológico , Dor do Câncer/etiologia , Antagonistas do Receptor Purinérgico P2X/administração & dosagem , Receptores Purinérgicos P2X7/metabolismo , Absorciometria de Fóton/métodos , Animais , Progressão da Doença , Relação Dose-Resposta a Droga , Medições Luminescentes , Morfina/farmacologia , Medição da Dor , Ratos , Ratos Sprague-Dawley , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
OBJECTIVES: To evaluate the role that intravesical P2X2/3 purinergic receptors (P2X2/3Rs) play in early and advanced neurogenic lower urinary tract (LUT) dysfunction after contusion spinal cord injury (SCI) in female rats. MATERIALS AND METHODS: Female Sprague-Dawley rats received a thoracic Th8/Th9 spinal cord contusion with either force of 100 kDy (cN); moderate) or 150 kDy (cN; severe); Sham rats had no injury. Evaluations on urethane-anesthetised rats were conducted at either 2 or 4 weeks after SCI. LUT electrical signals and changes in bladder pressure were simultaneously recorded using cystometry and a set of custom-made flexible microelectrodes, before and after intravesical application of the P2X2/3R antagonist AF-353 (10 µM), to determine the contribution of P2X2/3R-mediated LUT modulation. RESULTS: Severe SCI significantly increased bladder contraction frequency, and reduced both bladder pressure amplitude and intraluminal-pressure high-frequency oscillations (IPHFO). Intravesical P2X2/3R inhibition did not modify bladder pressure or IPHFO in the Sham and moderate-SCI rats, although did increase the intercontractile interval (ICI). At 2 weeks after SCI, the Sham and moderate-SCI rats had significant LUT electromyographic activity during voiding, with a noticeable reduction in LUT electrical signals seen at 4 weeks after SCI. Intravesical inhibition of P2X2/3R increased the ICI in the Sham and moderate-SCI rats at both time-points, but had no effect on rats with severe SCI. The external urethral sphincter (EUS) showed strong and P2X2/3R-independent electrical signals in the Sham and moderate-SCI rats in the early SCI stage. At 4 weeks after SCI, the responsiveness of the EUS was significantly attenuated, independently of SCI intensity. CONCLUSIONS: This study shows that electrophysiological properties of the LUT are progressively impaired depending on SCI intensity and that intravesical P2X2/3R inhibition can attenuate electrical activity in the neurogenic LUT at early, but not at semi-chronic SCI. This translational study should be useful for planning clinical evaluations.
Assuntos
Éteres Fenílicos/farmacologia , Antagonistas do Receptor Purinérgico P2X/farmacologia , Pirimidinas/farmacologia , Traumatismos da Medula Espinal/fisiopatologia , Uretra/fisiopatologia , Bexiga Urinaria Neurogênica/fisiopatologia , Micção/fisiologia , Administração Intravesical , Animais , Modelos Animais de Doenças , Eletromiografia , Feminino , Éteres Fenílicos/administração & dosagem , Antagonistas do Receptor Purinérgico P2X/administração & dosagem , Pirimidinas/administração & dosagem , Ratos , Ratos Sprague-Dawley , Transdução de Sinais , Uretra/efeitos dos fármacos , Micção/efeitos dos fármacosRESUMO
BACKGROUND: Central nervous system-derived interleukin-1ß plays a role in mood disorders. P2X7 receptor activation by adenosine-triphosphate leads to the release of interleukin-1ß. AIMS: This first-in-human study evaluated safety, tolerability, pharmacokinetics and pharmacodynamics of a novel central nervous system-penetrant P2X7 receptor antagonist, JNJ-54175446, in healthy participants. METHODS: The study had three parts: an ascending-dose study in fasted participants (0.5-300 mg JNJ-54175446); an ascending-dose study in fed participants (50-600 mg); and a cerebrospinal fluid study (300 mg). Target plasma concentrations were based on estimated plasma effective concentration (EC)50 (105 ng/mL) and EC90 (900 ng/mL) values for central nervous system P2X7 receptor binding. RESULTS: Seventy-seven participants received a single oral dose of JNJ-54175446 ( n=59) or placebo ( n=18). Area under the curve of concentration time extrapolated to infinity (AUC∞) increased dose-proportionally; maximum concentration (Cmax) of plasma (Cmax,plasma) increased less than dose-proportionally following single doses of JNJ-54175446. Because food increases bioavailability of JNJ-54175446, higher doses were given with food to evaluate safety at higher exposures. The highest Cmax,plasma reached (600 mg, fed) was 1475±163 ng/mL. JNJ-54175446 Cmax in cerebrospinal fluid, a proxy for brain penetration, was seven times lower than in total plasma; unbound Cmax,plasma and Cmax,CSF were comparable (88.3±35.7 vs 114±39 ng/mL). JNJ-54175446 inhibited lipopolysaccharide/3'-O-(4-benzoylbenzoyl)-ATP-induced interleukin-1ß release from peripheral blood in a dose-dependent manner (inhibitory concentration (IC)50:82 ng/mL; 95% confidence interval: 48-94). Thirty-three of 59 (55.9%) participants reported at least one treatment-emergent adverse event; the most common adverse event being headache (11/59, 18.6%). CONCLUSION: Plasma exposure of JNJ-54175446 was dose-dependent. No serious adverse events occurred. Single-dose administration of JNJ-54175446>10 mg attenuated ex-vivo lipopolysaccharide-induced interleukin-1ß release in peripheral blood. Passive brain penetration of JNJ-54175446 was confirmed.
Assuntos
Encéfalo/metabolismo , Interleucina-1beta/metabolismo , Antagonistas do Receptor Purinérgico P2X/administração & dosagem , Piridinas/administração & dosagem , Triazóis/administração & dosagem , Administração Oral , Adolescente , Adulto , Idoso , Área Sob a Curva , Disponibilidade Biológica , Relação Dose-Resposta a Droga , Método Duplo-Cego , Feminino , Interações Alimento-Droga , Humanos , Concentração Inibidora 50 , Lipopolissacarídeos/farmacologia , Masculino , Pessoa de Meia-Idade , Antagonistas do Receptor Purinérgico P2X/farmacocinética , Antagonistas do Receptor Purinérgico P2X/farmacologia , Piridinas/farmacocinética , Piridinas/farmacologia , Distribuição Tecidual , Triazóis/farmacocinética , Triazóis/farmacologia , Adulto JovemRESUMO
The P2X7 channel is involved in the pathogenesis of various CNS diseases. An increasing number of studies suggest its presence in neurons where its putative functions remain controversial for more than a decade. To resolve this issue and to provide a model for analysis of P2X7 functions, we generated P2X7 BAC transgenic mice that allow visualization of functional EGFP-tagged P2X7 receptors in vivo. Extensive characterization of these mice revealed dominant P2X7-EGFP protein expression in microglia, Bergmann glia, and oligodendrocytes, but not in neurons. These findings were further validated by microglia- and oligodendrocyte-specific P2X7 deletion and a novel P2X7-specific nanobody. In addition to the first quantitative analysis of P2X7 protein expression in the CNS, we show potential consequences of its overexpression in ischemic retina and post-traumatic cerebral cortex grey matter. This novel mouse model overcomes previous limitations in P2X7 research and will help to determine its physiological roles and contribution to diseases.
Assuntos
Córtex Cerebral/metabolismo , Neurônios/metabolismo , Antagonistas do Receptor Purinérgico P2X/administração & dosagem , Receptores Purinérgicos P2X7/genética , Trifosfato de Adenosina/metabolismo , Animais , Astrócitos/efeitos dos fármacos , Astrócitos/metabolismo , Astrócitos/patologia , Doenças do Sistema Nervoso Central/tratamento farmacológico , Doenças do Sistema Nervoso Central/genética , Doenças do Sistema Nervoso Central/patologia , Córtex Cerebral/efeitos dos fármacos , Córtex Cerebral/patologia , Modelos Animais de Doenças , Proteínas de Fluorescência Verde/química , Humanos , Camundongos , Camundongos Transgênicos , Microglia/efeitos dos fármacos , Microglia/metabolismo , Neurônios/patologia , Oligodendroglia/metabolismo , Oligodendroglia/patologiaRESUMO
Damage associated molecular patterns (DAMPs) are intracellular molecules released from infected or injured cells to activate inflammatory and reparatory responses. One of the most ancient and conserved DAMPs is extracellular ATP that exerts its phlogistic activity mainly through activation of the P2X7 receptor (P2X7R). The P2X7R is an ATP gated ion channel, expressed by most immune cells, including the monocyte-derived cell lineages, T and B lymphocytes and their precursors. Here we give an overview of recent and established literature on the role of P2X7R in septic and sterile inflammation. P2X7R ability in restraining intracellular bacteria and parasite infection by modulation of the immune response are described, with particular focus on Mycobacteria and Plasmodium. Emerging literature on the role of P2X7 in viral infections such as HIV-1 is also briefly covered. Finally, we describe the numerous intracellular pathways related to inflammation and activated by the P2X7R, including the NLRP3 inflammasome, NF-kB, NFAT, GSK3ß and VEGF, and discuss the involvement of P2X7R in chronic diseases. The possible therapeutic applications of P2X7R antagonists are also described.
Assuntos
Inflamação/tratamento farmacológico , Agonistas do Receptor Purinérgico P2X/uso terapêutico , Antagonistas do Receptor Purinérgico P2X/uso terapêutico , Receptores Purinérgicos P2X7/metabolismo , Animais , Doenças Autoimunes/tratamento farmacológico , Doenças Autoimunes/imunologia , Doenças Autoimunes/metabolismo , Doença Crônica , Ensaios Clínicos como Assunto , Doenças Transmissíveis/tratamento farmacológico , Doenças Transmissíveis/imunologia , Doenças Transmissíveis/metabolismo , Avaliação Pré-Clínica de Medicamentos , Humanos , Inflamassomos/metabolismo , Inflamação/imunologia , Inflamação/metabolismo , Neoplasias/tratamento farmacológico , Neoplasias/imunologia , Neoplasias/metabolismo , Doenças Neurodegenerativas/tratamento farmacológico , Doenças Neurodegenerativas/imunologia , Doenças Neurodegenerativas/metabolismo , Agonistas do Receptor Purinérgico P2X/administração & dosagem , Agonistas do Receptor Purinérgico P2X/efeitos adversos , Antagonistas do Receptor Purinérgico P2X/administração & dosagem , Antagonistas do Receptor Purinérgico P2X/efeitos adversosRESUMO
Glycoprotein 120 (gp120) is an HIV envelope glycoprotein. Gp120 can directly stimulate the primary sensory afferent neurons and cause hyperalgesia. The P2X3 receptor in dorsal root ganglia (DRG) is involved in the transmission of pain. In this study, we aimed to explore the role of the P2X3 receptor in gp120-induced neuropathic pain. Our data showed that mechanical and thermal hyperalgesia in rats treated with gp120 were increased compared to those in the control group. The expression levels of the P2X3 mRNA and protein in rats treated with gp120 were higher than those in the control group. The P2X3 antagonist A317491 decreased mechanical hyperalgesia and thermal hyperalgesia and the up-regulated expression levels of P2X3 mRNA and protein in rats treated with gp120. A317491 decreased ERK1/2 phosphorylation levels in the gp120-treated rat DRG. In addition, P2X3 agonist α,ß-methylene ATP (α,ß-meATP)-activated currents in DRG neurons cultured with gp120 were higher than those in control neurons. The inhibitory effect of A317491 on α,ßme-ATP-induced currents in DRG neurons from the gp120-treated neurons was larger than that for control neurons. Molecular docking data showed that A317491 may be acted in the gp120 protein to inhibit the gp120 initiated the P2X3 activation, decrease the sensitizing DRG primary afferents and reduce the signal transmission of neuropathic pain in gp120-treated rats. Therefore, the inhibition of the P2X3 receptor in rat DRG neurons relieved gp120-induced mechanical hyperalgesia.