scholarly journals The Sphingosine 1-Phosphate Receptor, S1PR1, Plays a Prominent But Not Exclusive Role in Enhancing the Excitability of Sensory Neurons

2010 ◽  
Vol 104 (5) ◽  
pp. 2741-2748 ◽  
Author(s):  
Xian Xuan Chi ◽  
G. D. Nicol
Keyword(s):  
Sensory Neurons ◽  
Small Diameter ◽  
Cell Types ◽  
G Protein Coupled Receptors ◽  
Rt Pcr ◽  
Additional Increase ◽  
Sphingosine 1 Phosphate ◽  
Subsequent Exposure ◽  
G Protein Coupled

Sphingosine 1-phosphate (S1P) through its interaction with a family of G protein–coupled receptors (S1PR) is proving to have a significant impact on the activation of a variety of cell types, most notably those cells mediating the inflammatory response. Previously, we showed that S1P enhanced the excitability of small diameter sensory neurons, and mRNA for S1PR1–4 was expressed in sensory neurons. These initial findings did not determine which S1PR subtype(s) mediated the increased excitability. Here, we report that exposure to the selective S1PR1 agonist, SEW2871, produced a significant increase in excitability of some, but not all, sensory neurons. To further examine the role of S1PR1, neurons were treated with siRNA targeted to S1PR1. siRNA reduced S1PR1 protein expression by 75% and blocked the sensitization produced by SEW2871, although some neurons remained responsive to subsequent exposure to S1P. Treatment with scramble siRNA did not alter S1PR1 expression. Recordings from siRNA- and scramble-treated neurons suggested three distinct populations based on their sensitivities to SEW2871 and S1P. Approximately 50% of the neurons exhibited a significant increase in excitability after exposure to SEW2871 and subsequent S1P produced no additional increase; ∼25% were not affected by SEW2871 but S1P significantly increased excitability; and ∼25% of the neurons were not sensitized by either SEW2871 or S1P. RT-PCR measurements obtained from single neurons showed that 50% of the small diameter neurons expressed the mRNA for S1PR1. These results indicate that S1PR1 plays a prominent, although not exclusive, role in mediating the enhancement of excitability produced by S1P.

Sphingosine-1-Phosphate Via Activation of a G-Protein-Coupled Receptor(s) Enhances the Excitability of Rat Sensory Neurons

2006 ◽  
Vol 96 (3) ◽  
pp. 1042-1052 ◽  
Author(s):  
Y. H. Zhang ◽  
J. C. Fehrenbacher ◽  
M. R. Vasko ◽  
G. D. Nicol
Keyword(s):  
G Protein ◽  
Sensory Neurons ◽  
Small Diameter ◽  
G Protein Coupled Receptors ◽  
External Application ◽  
Nociceptive Neurons ◽  
Firing Threshold ◽  
Current Ramp ◽  
Sphingosine 1 Phosphate ◽  
G Protein Coupled

Sphingosine-1-phosphate (S1P) is released by immune cells and is thought to play a key role in chemotaxis and the onset of the inflammatory response. The question remains whether this lipid mediator also contributes to the enhanced sensitivity of nociceptive neurons that is associated with inflammation. Therefore we examined whether S1P alters the excitability of small diameter, capsaicin-sensitive sensory neurons by measuring action potential (AP) firing and two of the membrane currents critical in regulating the properties of the AP. External application of S1P augments the number of APs evoked by a depolarizing current ramp. The enhanced firing is associated with a decrease in the rheobase and an increase in the resistance at firing threshold although neither the firing threshold nor the resting membrane potential are changed. Treatment with S1P enhanced the tetrodotoxin-resistant sodium current and decreased the total outward potassium current ( IK). When sensory neurons were internally perfused with GDP-β-S, a blocker of G protein activation, the S1P-induced increase in APs was completely blocked and suggests the excitatory actions of S1P are mediated through G-protein-coupled receptors called endothelial differentiation gene or S1PR. In contrast, internal perfusion with GDP-β-S and S1P increased the number of APs evoked by the current ramp. These results and our finding that the mRNAs for S1PRs are expressed in both the intact dorsal root ganglion and cultures of adult sensory neurons supports the notion that S1P acts on S1PRs linked to G proteins. Together these findings demonstrate that S1P can regulate the excitability of small diameter sensory neurons by acting as an external paracrine-type ligand through activation of G-protein-coupled receptors and thus may contribute to the hypersensitivity during inflammation.

scholarly journals Sphingosine 1-phosphate receptor 2 antagonist JTE-013 increases the excitability of sensory neurons independently of the receptor

2012 ◽  
Vol 108 (5) ◽  
pp. 1473-1483 ◽  
Author(s):  
Chao Li ◽  
Xian Xuan Chi ◽  
Wenrui Xie ◽  
J. A. Strong ◽  
J.-M. Zhang ◽  
...  
Keyword(s):  
G Protein ◽  
Sensory Neurons ◽  
Neuronal Excitability ◽  
Small Diameter ◽  
G Protein Coupled Receptors ◽  
Prostaglandin E ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Sphingosine 1 Phosphate ◽  
G Protein Coupled

Previously we demonstrated that sphingosine 1-phosphate receptor 1 (S1PR1) played a prominent, but not exclusive, role in enhancing the excitability of small-diameter sensory neurons, suggesting that other S1PRs can modulate neuronal excitability. To examine the potential role of S1PR2 in regulating neuronal excitability we used the established selective antagonist of S1PR2, JTE-013. Here we report that exposure to JTE-013 alone produced a significant increase in excitability in a time- and concentration-dependent manner in 70–80% of recorded neurons. Internal perfusion of sensory neurons with guanosine 5′- O-(2-thiodiphosphate) (GDP-β-S) via the recording pipette inhibited the sensitization produced by JTE-013 as well as prostaglandin E2. Pretreatment with pertussis toxin or the selective S1PR1 antagonist W146 blocked the sensitization produced by JTE-013. These results indicate that JTE-013 might act as an agonist at other G protein-coupled receptors. In neurons that were sensitized by JTE-013, single-cell RT-PCR studies demonstrated that these neurons did not express the mRNA for S1PR2. In behavioral studies, injection of JTE-013 into the rat's hindpaw produced a significant increase in the mechanical sensitivity in the ipsilateral, but not contralateral, paw. Injection of JTE-013 did not affect the withdrawal latency to thermal stimulation. Thus JTE-013 augments neuronal excitability independently of S1PR2 by unknown mechanisms that may involve activation of other G protein-coupled receptors such as S1PR1. Clearly, further studies are warranted to establish the causal nature of this increased sensitivity, and future studies of neuronal function using JTE-013 should be interpreted with caution.

scholarly journals Signal Transduction of Sphingosine-1-Phosphate G Protein—Coupled Receptors

2006 ◽  
Vol 6 ◽  
pp. 946-966 ◽  
Author(s):  
Nicholas Young ◽  
James R. Van Brocklyn
Keyword(s):  
Signal Transduction ◽  
G Protein ◽  
Cell Types ◽  
G Protein Coupled Receptors ◽  
Lymphocyte Trafficking ◽  
Cytoskeletal Organization ◽  
Cellular Effects ◽  
Sphingosine 1 Phosphate ◽  
S1p Receptor ◽  
G Protein Coupled

Sphingosine-1-phosphate (S1P) is a bioactive lipid capable of eliciting dramatic effects in a variety of cell types. Signaling by this molecule is by a family of five G protein—coupled receptors named S1P1–5that signal through a variety of pathways to regulate cell proliferation, migration, cytoskeletal organization, and differentiation. These receptors are expressed in a wide variety of tissues and cell types, and their cellular effects contribute to important biological and pathological functions of S1P in many processes, including angiogenesis, vascular development, lymphocyte trafficking, and cancer. This review will focus on the current progress in the field of S1P receptor signaling and biology.

scholarly journals The Biology of Vasopressin

Biomedicines ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 89
Author(s):  
Samantha Sparapani ◽  
Cassandra Millet-Boureima ◽  
Joshua Oliver ◽  
Kathy Mu ◽  
Pegah Hadavi ◽  
...  
Keyword(s):  
Parental Behavior ◽  
Cell Types ◽  
G Protein Coupled Receptors ◽  
Receptor Expression ◽  
Evolutionarily Conserved ◽  
Terrestrial Environments ◽  
Intracellular Vesicles ◽  
G Protein Coupled ◽  
Neuropsychiatric Conditions ◽  
Vasopressin Synthesis

Vasopressins are evolutionarily conserved peptide hormones. Mammalian vasopressin functions systemically as an antidiuretic and regulator of blood and cardiac flow essential for adapting to terrestrial environments. Moreover, vasopressin acts centrally as a neurohormone involved in social and parental behavior and stress response. Vasopressin synthesis in several cell types, storage in intracellular vesicles, and release in response to physiological stimuli are highly regulated and mediated by three distinct G protein coupled receptors. Other receptors may bind or cross-bind vasopressin. Vasopressin is regulated spatially and temporally through transcriptional and post-transcriptional mechanisms, sex, tissue, and cell-specific receptor expression. Anomalies of vasopressin signaling have been observed in polycystic kidney disease, chronic heart failure, and neuropsychiatric conditions. Growing knowledge of the central biological roles of vasopressin has enabled pharmacological advances to treat these conditions by targeting defective systemic or central pathways utilizing specific agonists and antagonists.

scholarly journals Integrating High-Content Analysis into a Multiplexed Screening Approach to Identify and Characterize GPCR Agonists

2014 ◽  
Vol 19 (7) ◽  
pp. 1079-1089 ◽  
Author(s):  
Yingjie Zhu ◽  
John Watson ◽  
Mengjie Chen ◽  
Ding Ren Shen ◽  
Melissa Yarde ◽  
...  
Keyword(s):  
Drug Discovery ◽  
G Protein Coupled Receptors ◽  
High Content Imaging ◽  
Biased Agonism ◽  
Receptor Oligomerization ◽  
Sphingosine 1 Phosphate ◽  
High Content Analysis ◽  
Screening Assays ◽  
Hit Identification ◽  
G Protein Coupled

G protein–coupled receptors (GPCRs) are one of the most popular and proven target classes for therapeutic intervention. The increased appreciation for allosteric modulation, receptor oligomerization, and biased agonism has led to the development of new assay platforms that seek to capitalize on these aspects of GPCR biology. High-content screening is particularly well suited for GPCR drug discovery given the ability to image and quantify changes in multiple cellular parameters, to resolve subcellular structures, and to monitor events within a physiologically relevant environment. Focusing on the sphingosine-1-phosphate (S1P1) receptor, we evaluated the utility of high-content approaches in hit identification efforts by developing and applying assays to monitor β-arrestin translocation, GPCR internalization, and GPCR recycling kinetics. Using these approaches in combination with more traditional GPCR screening assays, we identified compounds whose unique pharmacological profiles would have gone unnoticed if using a single platform. In addition, we identified a compound that induces an atypical pattern of β-arrestin translocation and GPCR recycling kinetics. Our results highlight the value of high-content imaging in GPCR drug discovery efforts and emphasize the value of a multiassay approach to study pharmacological properties of compounds of interest.

scholarly journals A Minimal Model for G Protein–Mediated Synaptic Facilitation and Depression

2003 ◽  
Vol 90 (3) ◽  
pp. 1643-1653 ◽  
Author(s):  
Richard Bertram ◽  
Jessica Swanson ◽  
Mohammad Yousef ◽  
Zhong-Ping Feng ◽  
Gerald W. Zamponi
Keyword(s):  
G Protein ◽  
Cell Types ◽  
G Protein Coupled Receptors ◽  
Β Subunit ◽  
Short Term ◽  
Paired Pulse ◽  
Synaptic Facilitation ◽  
Protein Inhibition ◽  
G Protein Coupled ◽  
High Pass

G protein–coupled receptors are ubiquitous in neurons, as well as other cell types. Activation of receptors by hormones or neurotransmitters splits the G protein heterotrimer into Gα and Gβγ subunits. It is now clear that Gβγ directly inhibits Ca2+ channels, putting them into a reluctant state. The effects of Gβγ depend on the specific β and γ subunits present, as well as the β subunit isoform of the N-type Ca2+ channel. We describe a minimal mathematical model for the effects of G protein action on the dynamics of synaptic transmission. The model is calibrated by data obtained by transfecting G protein and Ca2+ channel subunits into tsA-201 cells. We demonstrate with numerical simulations that G protein action can provide a mechanism for either short-term synaptic facilitation or depression, depending on the manner in which G protein–coupled receptors are activated. The G protein action performs high-pass filtering of the presynaptic signal, with a filter cutoff that depends on the combination of G protein and Ca2+ channel subunits present. At stimulus frequencies above the cutoff, trains of single spikes are transmitted, while only doublets are transmitted at frequencies below the cutoff. Finally, we demonstrate that relief of G protein inhibition can contribute to paired-pulse facilitation.

scholarly journals Role of Taste Receptors as Sentinels of Innate Immunity in the Upper Airway

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Neil N. Patel ◽  
Alan D. Workman ◽  
Noam A. Cohen
Keyword(s):  
Airway Epithelium ◽  
Taste Receptor ◽  
Upper Airway ◽  
Airway Disease ◽  
G Protein Coupled Receptors ◽  
Innate Immune ◽  
Taste Receptors ◽  
Taste Sensation ◽  
G Protein Coupled

Evidence is emerging that shows taste receptors serve functions outside of taste sensation of the tongue. Taste receptors have been found in tissue across the human body, including the gastrointestinal tract, bladder, brain, and airway. These extraoral taste receptors appear to be important in modulating the innate immune response through detection of pathogens. This review discusses taste receptor signaling, focusing on the G-protein–coupled receptors that detect bitter and sweet compounds in the upper airway epithelium. Emphasis is given to recent studies which link the physiology of sinonasal taste receptors to clinical manifestation of upper airway disease.

Compartmentalization of GPCR signalling controls unique cellular responses

2016 ◽  
Vol 44 (2) ◽  
pp. 562-567 ◽  
Author(s):  
Andrew M. Ellisdon ◽  
Michelle L. Halls
Keyword(s):  
Drug Discovery ◽  
Drug Targets ◽  
Cell Types ◽  
G Protein Coupled Receptors ◽  
Attrition Rates ◽  
Physiological Processes ◽  
Simple Chain ◽  
G Protein Coupled ◽  
Major Drug ◽  
Very High

With >800 members, G protein-coupled receptors (GPCRs) are the largest class of cell-surface signalling proteins, and their activation mediates diverse physiological processes. GPCRs are ubiquitously distributed across all cell types, involved in many diseases and are major drug targets. However, GPCR drug discovery is still characterized by very high attrition rates. New avenues for GPCR drug discovery may be provided by a recent shift away from the traditional view of signal transduction as a simple chain of events initiated from the plasma membrane. It is now apparent that GPCR signalling is restricted to highly organized compartments within the cell, and that GPCRs activate distinct signalling pathways once internalized. A high-resolution understanding of how compartmentalized signalling is controlled will probably provide unique opportunities to selectively and therapeutically target GPCRs.

scholarly journals The Role of G Protein-Coupled Receptors in the Right Ventricle in Pulmonary Hypertension

2018 ◽  
Vol 5 ◽  
Author(s):  
Gayathri Viswanathan ◽  
Argen Mamazhakypov ◽  
Ralph T. Schermuly ◽  
Sudarshan Rajagopal
Keyword(s):  
Pulmonary Hypertension ◽  
Right Ventricle ◽  
G Protein ◽  
G Protein Coupled Receptors ◽  
The Right ◽  
G Protein Coupled

scholarly journals Dopamine and GPCR-mediated modulation of DN1 clock neurons gates the circadian timing of sleep

2021 ◽  
Author(s):  
Matthias Schlichting ◽  
Shlesha Richhariya ◽  
Nicholas Herndon ◽  
Dingbang Ma ◽  
Jason Xin ◽  
...  
Keyword(s):  
G Protein Coupled Receptors ◽  
Sleep Regulation ◽  
Single Cell Sequencing ◽  
Sleep Timing ◽  
Clock Network ◽  
Sleep Centers ◽  
Neuron Synchronization ◽  
G Protein Coupled ◽  
Behavioral Screen

The metronome-like circadian regulation of sleep timing must still adapt to an uncertain environment. Recent studies in Drosophila indicate that neuromodulation not only plays a key role in clock neuron synchronization but also affects interactions between the clock network and brain sleep centers. We show here that the targets of neuromodulators, G-Protein Coupled Receptors (GPCRs), are highly enriched in the fly brain circadian clock network. Single cell sequencing indicates that they are not only differentially expressed but also define clock neuron identity. We generated a comprehensive guide library to mutagenize individual GPCRs in specific neurons and verified the strategy with a targeted sequencing approach. Combined with a behavioral screen, the mutagenesis strategy revealed a novel role of dopamine in sleep regulation by identifying two dopamine receptors and a clock neuron subpopulation that gate the timing of sleep.

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