Proper determination of agonist efficacy is indispensable in the evaluation of agonist selectivity and bias to activation of specific signalling pathways. The operational model (OM) of pharmacological agonism is a useful means for achieving this goal. Allosteric ligands bind to receptors at sites that are distinct from those of endogenous agonists that interact with the orthosteric domain on the receptor. An allosteric modulator and an orthosteric agonist bind simultaneously to the receptor to form a ternary complex, where the allosteric modulator affects the binding affinity and operational efficacy of the agonist. Allosteric modulators are an intensively studied group of receptor ligands because of their selectivity and preservation of physiological space-time pattern of the signals they modulate. We analysed the operational model of allosterically-modulated agonism (OMAM) including modulation by allosteric agonists. Similar to OM, several parameters of OMAM are inter-dependent. We derived equations describing mutual relationships among parameters of the functional response and OMAM. We present a workflow for the robust fitting of OMAM to experimental data using derived equations.

• MeSH
• alosterická regulace MeSH
• kinetika MeSH
• lidé MeSH
• ligandy MeSH
• receptory spřažené s G-proteiny agonisté   metabolismus   MeSH
• synergismus léků * MeSH
• vazba proteinů MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Allosteric ligands bind to receptors at sites that are distinct from those endogenous agonists and orthosteric pharmacological agents interact with. Both an allosteric and orthosteric ligand bind simultaneously to the receptor to form a ternary complex, where each ligand influences binding affinity of the other to the receptor, either positively or negatively. Allosteric modulators are an intensively studied group of receptor ligands because of their potentially greater selectivity over orthosteric ligands, with the possibility of fine tuning of the effects of endogenous neurotransmitters and hormones. The affinity of an unlabelled allosteric ligand is commonly estimated by measuring its effects on binding of a radio-labelled orthosteric tracer. This scenario is complicated by many folds when one studies the kinetics of interactions of two allosteric agents, added simultaneously, on binding of an orthosteric tracer. In this paper, we provide, for the first time, theoretical basis for analysis of such complex interactions. We have expanded our analysis to include the possibility of having two allosteric modulators interact with the same or different sites on the receptor. An added value of our analysis is to provide a tool to distinguish between the two situations. Finally, we also modelled binding of two molecules of one allosteric modulator to one receptor.

• MeSH
• alosterická regulace MeSH
• alosterické místo MeSH
• chemické modely * MeSH
• kinetika MeSH
• ligandy MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Ivermectin acts as a positive allosteric regulator of several ligand-gated channels including the glutamate-gated chloride channel (GluCl), gamma aminobutyric acid type-A receptor, glycine receptor, neuronal alpha7-nicotinic receptor and purinergic P2X4 receptor. In most of the ivermectin-sensitive channels, the effects of ivermectin include the potentiation of agonist-induced currents at low concentrations and channel opening at higher concentrations. Based on mutagenesis, electrophysiological recordings and functional analysis of chimeras between ivermectin-sensitive and ivermectin-insensitive receptors, it has been concluded that ivermectin acts by insertion between transmembrane helices. The three-dimensional structure of C. elegans GluCl complexed with ivermectin has revealed the details of the ivermectin-binding site, however, no generic motif of amino acids could accurately predict ivermectin binding site for other ligand gated channels. Here, we will review what is currently known about ivermectin binding and modulation of Cys-loop receptor family of ligand-gated ion channels and what are the critical structural determinants underlying potentiation of the P2X4 receptor channel.

• MeSH
• alosterická regulace MeSH
• alosterické místo MeSH
• biologické modely MeSH
• chemické modely MeSH
• gating iontového kanálu * MeSH
• iontové kanály chemie   metabolismus   ultrastruktura   MeSH
• ivermektin chemie   MeSH
• molekulární konformace MeSH
• molekulární modely MeSH
• počítačová simulace MeSH
• vazba proteinů MeSH
• vazebná místa MeSH
• vztahy mezi strukturou a aktivitou MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH

• MeSH
• alosterická regulace MeSH
• receptory muskarinové MeSH
• vazebná místa MeSH

N-Methyl-D-aspartate receptors (NMDARs) are ionotropic glutamate receptors essential for synaptic plasticity and memory. Receptor activation involves glycine- and glutamate-stabilized closure of the GluN1 and GluN2 subunit ligand binding domains that is allosterically regulated by the amino-terminal domain (ATD). Using single molecule fluorescence resonance energy transfer (smFRET) to monitor subunit rearrangements in real-time, we observe a stable ATD inter-dimer distance in the Apo state and test the effects of agonists and antagonists. We find that GluN1 and GluN2 have distinct gating functions. Glutamate binding to GluN2 subunits elicits two identical, sequential steps of ATD dimer separation. Glycine binding to GluN1 has no detectable effect, but unlocks the receptor for activation so that glycine and glutamate together drive an altered activation trajectory that is consistent with ATD dimer separation and rotation. We find that protons exert allosteric inhibition by suppressing the glutamate-driven ATD separation steps, and that greater ATD separation translates into greater rotation and higher open probability.

• MeSH
• alosterická regulace MeSH
• glycin chemie   metabolismus   MeSH
• HEK293 buňky MeSH
• kinetika MeSH
• konfokální mikroskopie MeSH
• konformace proteinů * MeSH
• kyselina glutamová chemie   metabolismus   MeSH
• lidé MeSH
• molekulární modely MeSH
• multimerizace proteinu * MeSH
• receptory N-methyl-D-aspartátu chemie   genetika   metabolismus   MeSH
• rezonanční přenos fluorescenční energie metody   MeSH
• vazba proteinů MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH

• Konspekt
• Biochemie. Molekulární biologie. Biofyzika
• NLK Obory
• biochemie
• fyziologie
• farmacie a farmakologie

Allosteric modulators are ligands that bind to a site on the receptor that is spatially separated from the orthosteric binding site for the endogenous neurotransmitter. Allosteric modulators modulate the binding affinity, potency, and efficacy of orthosteric ligands. Muscarinic acetylcholine receptors are prototypical allosterically-modulated G-protein-coupled receptors. They are a potential therapeutic target for the treatment of psychiatric, neurologic, and internal diseases like schizophrenia, Alzheimer's disease, Huntington disease, type 2 diabetes, or chronic pulmonary obstruction. Here, we reviewed the progress made during the last decade in our understanding of their mechanisms of binding, allosteric modulation, and in vivo actions in order to understand the translational impact of studying this important class of pharmacological agents. We overviewed newly developed allosteric modulators of muscarinic receptors as well as new spin-off ideas like bitopic ligands combining allosteric and orthosteric moieties and photo-switchable ligands based on bitopic agents.

• MeSH
• agonisté muskarinových receptorů metabolismus   MeSH
• alosterická regulace fyziologie   MeSH
• antagonisté muskarinových receptorů metabolismus   MeSH
• lidé MeSH
• ligandy MeSH
• receptory muskarinové metabolismus   fyziologie   MeSH
• receptory spřažené s G-proteiny MeSH
• vazebná místa MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH

The membrane cholesterol was found to bind and modulate the function of several G-protein coupled receptors including muscarinic acetylcholine receptors. We investigated the binding of 20 steroidal compounds including neurosteroids and steroid hormones to muscarinic receptors. Corticosterone, progesterone and some neurosteroids bound to muscarinic receptors with the affinity of 100 nM or greater. We established a structure-activity relationship for steroid-based allosteric modulators of muscarinic receptors. Further, we show that corticosterone and progesterone allosterically modulate the functional response of muscarinic receptors to acetylcholine at physiologically relevant concentrations. It can play a role in stress control or in pregnancy, conditions where levels of these hormones dramatically oscillate. Allosteric modulation of muscarinic receptors via the cholesterol-binding site represents a new pharmacological approach at diseases associated with altered cholinergic signalling.

• MeSH
• acetylcholin metabolismus   MeSH
• alosterická regulace MeSH
• hormony kůry nadledvin metabolismus   MeSH
• kortikosteron metabolismus   MeSH
• křečci praví MeSH
• kultivované buňky MeSH
• lidé MeSH
• neurosteroidy metabolismus   MeSH
• pohlavní steroidní hormony metabolismus   MeSH
• progesteron metabolismus   MeSH
• receptory muskarinové metabolismus   MeSH
• zvířata MeSH
• Check Tag
• křečci praví MeSH
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

INTRODUCTION: Multiple Sclerosis (MS), a debilitating central nervous system (CNS) disorder, is characterized by inflammation, demyelination, and neuronal degeneration. Despite advancements in immunomodulatory treatments, neuroprotective or restorative strategies remain inadequate. Our research is focusing on the potential of the positive allosteric modulator of AMPA receptors (AMPA-PAM), PF4778574, in addressing MS symptoms. METHODS: We utilized the MOG35-55 induced experimental autoimmune encephalomyelitis (EAE) model in C57BL6J mice to examine PF4778574's therapeutic and prophylactic efficacy. Our comprehensive approach included clinical scoring, optical coherence tomography (OCT), optomotor response (OMR) and histological assessments. Additionally, we explored the effects of PF4778574 in comparison and in combination with the immunomodulatory agent fingolimod, and investigated the impact on Cuprizone induced toxic demyelination. RESULTS: Prophylactic administration of PF4778574 showed notable improvement in clinical EAE indices and reduction in neuronal loss. While it did not diminish microglial activity, it reduced demyelinated areas in optic nerves and in the corpus callosum. Both PF4778574 and fingolimod significantly enhanced clinical EAE scores and decreased demyelination. However, their combination did not yield additional benefits. In the cuprizone model, PF4778574 increased oligodendrocyte precursor and mature myelin-forming cells, suggesting a pro-remyelinating effect. DISCUSSION: PF4778574 demonstrates promise in mitigating EAE effects, especially in terms of clinical disability and demyelination. These results suggest AMPA-PAMs as potential targets of interest for MS treatment beyond immunomodulatory approaches.

• MeSH
• alosterická regulace MeSH
• AMPA receptory * metabolismus   MeSH
• demyelinizační nemoci farmakoterapie   metabolismus   MeSH
• encefalomyelitida autoimunitní experimentální * farmakoterapie   metabolismus   imunologie   MeSH
• fingolimod hydrochlorid farmakologie   terapeutické užití   MeSH
• modely nemocí na zvířatech MeSH
• myši inbrední C57BL * MeSH
• myši MeSH
• roztroušená skleróza * farmakoterapie   metabolismus   imunologie   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

G-protein coupled receptors (GPCRs) are membrane proteins that convey extracellular signals to the cellular milieu. They represent a target for more than 30% of currently marketed drugs. Here we review the effects of membrane cholesterol on the function of GPCRs of Class A. We review both the specific effects of cholesterol mediated via its direct high-affinity binding to the receptor and non-specific effects mediated by cholesterol-induced changes in the properties of the membrane. Cholesterol binds to many GPCRs at both canonical and non-canonical binding sites. It allosterically affects ligand binding to and activation of GPCRs. Additionally, it changes the oligomerization state of GPCRs. In this review, we consider a perspective of the potential for the development of new therapies that are targeted at manipulating the level of membrane cholesterol or modulating cholesterol binding sites on to GPCRs.

• MeSH
• alosterická regulace MeSH
• anticholesteremika farmakologie   terapeutické užití   MeSH
• buněčná membrána metabolismus   MeSH
• cholesterol chemie   metabolismus   MeSH
• cílená molekulární terapie metody   MeSH
• lidé MeSH
• ligandy MeSH
• receptory spřažené s G-proteiny chemie   klasifikace   metabolismus   MeSH
• vazba proteinů MeSH
• vazebná místa účinky léků   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH