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1.
Int J Mol Sci ; 22(16)2021 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-34445634

RESUMO

Cannabinoids have been reported as orexigenic, i.e., as promoting food intake that, among others, is controlled by the so-called "hunger" hormone, ghrelin. The aim of this paper was to look for functional and/or molecular interactions between ghrelin GHSR1a and cannabinoid CB2 receptors at the central nervous system (CNS) level. In a heterologous system we identified CB2-GHSR1a receptor complexes with a particular heteromer print consisting of impairment of CB2 receptor/Gi-mediated signaling. The blockade was due to allosteric interactions within the heteromeric complex as it was reverted by antagonists of the GHSR1a receptor. Cannabinoids acting on the CB2 receptor did not affect cytosolic increases of calcium ions induced by ghrelin acting on the GHSR1a receptor. In situ proximity ligation imaging assays confirmed the expression of CB2-GHSR1a receptor complexes in both heterologous cells and primary striatal neurons. We tested heteromer expression in neurons from offspring of high-fat-diet mouse mothers as they have more risk to be obese. Interestingly, there was a marked upregulation of those complexes in striatal neurons from siblings of pregnant female mice under a high-fat diet.


Assuntos
Corpo Estriado/patologia , Dieta Hiperlipídica/efeitos adversos , Grelina/metabolismo , Neurônios/patologia , Obesidade/patologia , Receptor CB2 de Canabinoide/metabolismo , Receptores de Grelina/metabolismo , Animais , Canabinoides/farmacologia , Corpo Estriado/efeitos dos fármacos , Corpo Estriado/metabolismo , Feminino , Grelina/genética , Camundongos , Camundongos Endogâmicos C57BL , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Obesidade/etiologia , Obesidade/metabolismo , Receptor CB2 de Canabinoide/genética , Receptores de Grelina/genética , Transdução de Sinais , Regulação para Cima
2.
Redox Biol ; 46: 102078, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34333284

RESUMO

ACE2 plays a pivotal role in the balance between the pro-oxidative pro-inflammatory and the anti-oxidative anti-inflammatory arms of the renin-angiotensin system. Furthermore, ACE2 is the entry receptor for SARS-CoV-2. Clarification of ACE2-related mechanisms is crucial for the understanding of COVID-19 and other oxidative stress and inflammation-related processes. In rat and monkey brain, we discovered that the intracellular ACE2 and its products Ang 1-7 and alamandine are highly concentrated in the mitochondria and bind to a new mitochondrial Mas-related receptor MrgE (MrgE) to produce nitric oxide. We found MrgE expressed in neurons and glia of rodents and primates in the substantia nigra and different brain regions. In the mitochondria, ACE2 and MrgE expressions decreased and NOX4 increased with aging. This new ACE2/MrgE/NO axis may play a major role in mitochondrial regulation of oxidative stress in neurons, and possibly other cells. Therefore, dysregulation of the mitochondrial ACE2/MrgE/NO axis may play a major role in neurodegenerative processes of dopaminergic neurons, where mitochondrial dysfunction and oxidative stress play a crucial role. Since ACE2 binds SARS-CoV-2 spike protein, the mitochondrial ACE2/MrgE/NO axis may also play a role in SARS-CoV-2 cellular effects.


Assuntos
Enzima de Conversão de Angiotensina 2/metabolismo , Neurônios Dopaminérgicos/metabolismo , Mitocôndrias/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Animais , COVID-19 , Humanos , Primatas , Ratos , Roedores , SARS-CoV-2 , Glicoproteína da Espícula de Coronavírus
3.
Cells ; 10(5)2021 05 07.
Artigo em Inglês | MEDLINE | ID: mdl-34066933

RESUMO

Neuronal survival depends on the glia, that is, on the astroglial and microglial support. Neurons die and microglia are activated not only in neurodegenerative diseases but also in physiological aging. Activated microglia, once considered harmful, express two main phenotypes: the pro-inflammatory or M1, and the neuroprotective or M2. When neuroinflammation, i.e., microglial activation occurs, it is important to achieve a good M1/M2 balance, i.e., at some point M1 microglia must be skewed into M2 cells to impede chronic inflammation and to afford neuronal survival. G protein-coupled receptors in general and adenosine receptors in particular are potential targets for increasing the number of M2 cells. This article describes the mechanisms underlying microglial activation and analyzes whether these cells exposed to a first damaging event may be ready to be preconditioned to better react to exposure to more damaging events. Adenosine receptors are relevant due to their participation in preconditioning. They can also be overexpressed in activated microglial cells. The potential of adenosine receptors and complexes formed by adenosine receptors and cannabinoids as therapeutic targets to provide microglia-mediated neuroprotection is here discussed.

4.
Int J Mol Sci ; 22(9)2021 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-33924963

RESUMO

The mechanism of nigral dopaminergic neuronal degeneration in Parkinson's disease (PD) is unknown. One of the pathological characteristics of the disease is the deposition of α-synuclein (α-syn) that occurs in the brain from both familial and sporadic PD patients. This paper constitutes a narrative review that takes advantage of information related to genes (SNCA, LRRK2, GBA, UCHL1, VPS35, PRKN, PINK1, ATP13A2, PLA2G6, DNAJC6, SYNJ1, DJ-1/PARK7 and FBXO7) involved in familial cases of Parkinson's disease (PD) to explore their usefulness in deciphering the origin of dopaminergic denervation in many types of PD. Direct or functional interactions between genes or gene products are evaluated using the Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) database. The rationale is to propose a map of the interactions between SNCA, the gene encoding for α-syn that aggregates in PD, and other genes, the mutations of which lead to early-onset PD. The map contrasts with the findings obtained using animal models that are the knockout of one of those genes or that express the mutated human gene. From combining in silico data from STRING-based assays with in vitro and in vivo data in transgenic animals, two likely mechanisms appeared: (i) the processing of native α-syn is altered due to the mutation of genes involved in vesicular trafficking and protein processing, or (ii) α-syn mutants alter the mechanisms necessary for the correct vesicular trafficking and protein processing. Mitochondria are a common denominator since both mechanisms require extra energy production, and the energy for the survival of neurons is obtained mainly from the complete oxidation of glucose. Dopamine itself can result in an additional burden to the mitochondria of dopaminergic neurons because its handling produces free radicals. Drugs acting on G protein-coupled receptors (GPCRs) in the mitochondria of neurons may hopefully end up targeting those receptors to reduce oxidative burden and increase mitochondrial performance. In summary, the analysis of the data of genes related to familial PD provides relevant information on the etiology of sporadic cases and might suggest new therapeutic approaches.


Assuntos
Doença de Parkinson/genética , Animais , Animais Geneticamente Modificados , Neurônios Dopaminérgicos/metabolismo , Humanos , Doença de Parkinson/metabolismo , Substância Negra/metabolismo , alfa-Sinucleína/metabolismo
5.
Neurotherapeutics ; 18(2): 998-1016, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33474655

RESUMO

The renin-angiotensin system (RAS) not only plays an important role in controlling blood pressure but also participates in almost every process to maintain homeostasis in mammals. Interest has recently increased because SARS viruses use one RAS component (ACE2) as a target-cell receptor. The occurrence of RAS in the basal ganglia suggests that the system may be targeted to improve the therapy of neurodegenerative diseases. RAS-related data led to the hypothesis that RAS receptors may interact with each other. The aim of this paper was to find heteromers formed by Mas and angiotensin receptors and to address their functionality in neurons and microglia. Novel interactions were discovered by using resonance energy transfer techniques. The functionality of individual and interacting receptors was assayed by measuring levels of the second messengers cAMP and Ca2+ in transfected human embryonic kidney cells (HEK-293T) and primary cultures of striatal cells. Receptor complex expression was assayed by in situ proximity ligation assay. Functionality and expression were assayed in parallel in primary cultures of microglia treated or not with lipopolysaccharide and interferon-γ (IFN-γ). The proximity ligation assay was used to assess heteromer expression in parkinsonian and dyskinetic conditions. Complexes formed by Mas and the angiotensin AT1 or AT2 receptors were identified in both a heterologous expression system and in neural primary cultures. In the heterologous system, we showed that the three receptors-MasR, AT1R, and AT2R-can interact to form heterotrimers. The expression of receptor dimers (AT1R-MasR or AT2R-MasR) was higher in microglia than in neurons and was differentially affected upon microglial activation with lipopolysaccharide and IFN-γ. In all cases, agonist-induced signaling was reduced upon coactivation, and in some cases just by coexpression. Also, the blockade of signaling of two receptors in a complex by the action of a given (selective) receptor antagonist (cross-antagonism) was often observed. Differential expression of the complexes was observed in the striatum under parkinsonian conditions and especially in animals rendered dyskinetic by levodopa treatment. The negative modulation of calcium mobilization (mediated by AT1R activation), the multiplicity of possibilities on RAS affecting the MAPK pathway, and the disbalanced expression of heteromers in dyskinesia yield new insight into the operation of the RAS system, how it becomes unbalanced, and how a disbalanced RAS can be rebalanced. Furthermore, RAS components in activated microglia warrant attention in drug-development approaches to address neurodegeneration.

6.
Adv Exp Med Biol ; 1264: 81-92, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33332005

RESUMO

Three prevalent neurodegenerative diseases, Parkinson's, Alzheimer's, and Huntington's are in need of symptomatic relief of slowing disease progression or both. This chapter focuses on the potential of cannabinoids to afford neuroprotection, i.e. avoid or retard neuronal death. The neuroprotective potential of cannabinoids is known from the work in animal models and is mediated by the two cannabinoid receptors (CB1/CB2) and eventually, by their heteromers, GPR55, orphan receptors (GPR3/GPR6/GPR12/GPR18), or PPARγ. Now, there is the time to translate the findings into patients. The chapter takes primarily into account advances since 2016 and addresses the issue of proving neuroprotection in humans. One recent discovery is the existence of activated microglia with neuroprotective phenotype; cannabinoids are good candidates to skew phenotype, especially via glial CB2 receptors (CB2R), whose targeting has, a priori, less side effects those targeting the CBs1 receptor (CB1R), which are expressed in both neurons and glia. The fact that a cannabis extract (SativexTM) is approved for human therapy, such that cannabis use will likely be legalized in many countries and different possibilities that cannabinoid pharmacology suggests a successful route of cannabinoids (natural or synthetic) all the way to be approved and used in the treatment of neurodegeneration.


Assuntos
Doença de Alzheimer/tratamento farmacológico , Canabinoides/farmacologia , Canabinoides/uso terapêutico , Doença de Huntington/tratamento farmacológico , Neuroproteção/efeitos dos fármacos , Fármacos Neuroprotetores/farmacologia , Fármacos Neuroprotetores/uso terapêutico , Doença de Parkinson/tratamento farmacológico , Animais , Humanos
7.
Int J Mol Sci ; 21(24)2020 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-33339432

RESUMO

Angiotensin-converting enzyme 2 (ACE2) is a membrane peptidase and a component of the renin-angiotensin system (RAS) that has been found in cells of all organs, including the lungs. While ACE2 has been identified as the receptor for severe acute respiratory syndrome (SARS) coronaviruses, the mechanism underlying cell entry remains unknown. Human immunodeficiency virus infects target cells via CXC chemokine receptor 4 (CXCR4)-mediated endocytosis. Furthermore, CXCR4 interacts with dipeptidyl peptidase-4 (CD26/DPPIV), an enzyme that cleaves CXCL12/SDF-1, which is the chemokine that activates this receptor. By analogy, we hypothesized that ACE2 might also be capable of interactions with RAS-associated G-protein coupled receptors. Using resonance energy transfer and cAMP and mitogen-activated protein kinase signaling assays, we found that human ACE2 interacts with RAS-related receptors, namely the angiotensin II type 1 receptor (AT1R), the angiotensin II type 2 receptor (AT2R), and the MAS1 oncogene receptor (MasR). Although these interactions lead to minor alterations of signal transduction, ligand binding to AT1R and AT2R, but not to MasR, resulted in the upregulation of ACE2 cell surface expression. Proximity ligation assays performed in situ revealed macromolecular complexes containing ACE2 and AT1R, AT2R or MasR in adult but not fetal mouse lung tissue. These findings highlight the relevance of RAS in SARS-CoV-2 infection and the role of ACE2-containing complexes as potential therapeutic targets.


Assuntos
Enzima de Conversão de Angiotensina 2/metabolismo , COVID-19/patologia , Receptores CXCR4/metabolismo , Receptores Virais/metabolismo , SARS-CoV-2/metabolismo , Adulto , Linhagem Celular , Quimiocina CXCL12/metabolismo , Células HEK293 , Humanos , Peptidil Dipeptidase A/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Receptor Tipo 1 de Angiotensina/metabolismo , Receptor Tipo 2 de Angiotensina/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Sistema Renina-Angiotensina/fisiologia , Transdução de Sinais/fisiologia
8.
Comput Struct Biotechnol J ; 18: 2723-2732, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33101610

RESUMO

Biased agonism, the ability of agonists to differentially activate downstream signaling pathways by stabilizing specific receptor conformations, is a key issue for G protein-coupled receptor (GPCR) signaling. The C-terminal domain might influence this functional selectivity of GPCRs as it engages G proteins, GPCR kinases, ß-arrestins, and several other proteins. Thus, the aim of this paper is to compare the agonist-dependent selectivity for intracellular pathways in a heterologous system expressing the full-length (A2AR) and a C-tail truncated (A2A Δ40R lacking the last 40 amino acids) adenosine A2A receptor, a GPCR that is already targeted in Parkinson's disease using a first-in-class drug. Experimental data such as ligand binding, cAMP production, ß-arrestin recruitment, ERK1/2 phosphorylation and dynamic mass redistribution assays, which correspond to different aspects of signal transduction, were measured upon the action of structurally diverse compounds (the agonists adenosine, NECA, CGS-21680, PSB-0777 and LUF-5834 and the SCH-58261 antagonist) in cells expressing A2AR and A2A Δ40R. The results show that taking cAMP levels and the endogenous adenosine agonist as references, the main difference in bias was obtained with PSB-0777 and LUF-5834. The C-terminus is dispensable for both G-protein and ß-arrestin recruitment and also for MAPK activation. Unrestrained molecular dynamics simulations, at the µs timescale, were used to understand the structural arrangements of the binding cavity, triggered by these chemically different agonists, facilitating G protein binding with different efficacy.

9.
J Neuroinflammation ; 17(1): 243, 2020 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-32807174

RESUMO

BACKGROUND/AIMS: The renin-angiotensin system (RAS) is altered in Parkinson's disease (PD), a disease due to substantia nigra neurodegeneration and whose dopamine-replacement therapy, using the precursor levodopa, leads to dyskinesias as the main side effect. Angiotensin AT1 and AT2 receptors, mainly known for their role in regulating water homeostasis and blood pressure and able to form heterodimers (AT1/2Hets), are present in the central nervous system. We assessed the functionality and expression of AT1/2Hets in Parkinson disease (PD). METHODS: Immunocytochemistry was used to analyze the colocalization between angiotensin receptors; bioluminescence resonance energy transfer was used to detect AT1/2Hets. Calcium and cAMP determination, MAPK activation, and label-free assays were performed to characterize signaling in homologous and heterologous systems. Proximity ligation assays were used to quantify receptor expression in mouse primary cultures and in rat striatal sections. RESULTS: We confirmed that AT1 and AT2 receptors form AT1/2Hets that are expressed in cells of the central nervous system. AT1/2Hets are novel functional units with particular signaling properties. Importantly, the coactivation of the two receptors in the heteromer reduces the signaling output of angiotensin. Remarkably, AT1/2Hets that are expressed in both striatal neurons and microglia make possible that candesartan, the antagonist of AT1, increases the effect of AT2 receptor agonists. In addition, the level of striatal expression increased in the unilateral 6-OH-dopamine lesioned rat PD model and was markedly higher in parkinsonian-like animals that did not become dyskinetic upon levodopa chronic administration if compared with expression in those that became dyskinetic. CONCLUSION: The results indicate that boosting the action of neuroprotective AT2 receptors using an AT1 receptor antagonist constitutes a promising therapeutic strategy in PD.

10.
J Immunol ; 205(5): 1198-1206, 2020 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-32680957

RESUMO

Fever in infections correlates with inflammation, macrophage infiltration into the affected organ, macrophage activation, and release of cytokines involved in immune response, hematopoiesis, and homeostatic processes. Angiotensin-converting enzyme 2 (ACE2) is the canonical cell surface receptor for SARS-CoV-2. ACE2 together with angiotensin receptor types 1 and 2 and ACE2 are components of the renin-angiotensin system (RAS). Exacerbated production of cytokines, mainly IL-6, points to macrophages as key to understand differential COVID-19 severity. SARS-CoV-2 may modulate macrophage-mediated inflammation events by altering the balance between angiotensin II, which activates angiotensin receptor types 1 and 2, and angiotensin 1-7 and alamandine, which activate MAS proto-oncogene and MAS-related D receptors, respectively. In addition to macrophages, lung cells express RAS components; also, some lung cells are able to produce IL-6. Addressing how SARS-CoV-2 unbalances RAS functionality via ACE2 will help design therapies to attenuate a COVID-19-related cytokine storm.


Assuntos
Betacoronavirus/metabolismo , Infecções por Coronavirus/imunologia , Interleucina-6/biossíntese , Peptidil Dipeptidase A/metabolismo , Pneumonia Viral/imunologia , Sistema Renina-Angiotensina , Angiotensina I/metabolismo , Enzima de Conversão de Angiotensina 2 , Animais , Betacoronavirus/imunologia , COVID-19 , Infecções por Coronavirus/virologia , Humanos , Inflamação/imunologia , Macrófagos/imunologia , Pandemias , Fragmentos de Peptídeos/metabolismo , Pneumonia Viral/virologia , Proteínas Proto-Oncogênicas/metabolismo , Receptor Tipo 1 de Angiotensina/metabolismo , Receptor Tipo 2 de Angiotensina/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Receptores Virais/metabolismo , SARS-CoV-2
11.
Brain Struct Funct ; 225(7): 2153-2164, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32691218

RESUMO

Endocannabinoids are neuromodulators acting on specific cannabinoid CB1 and CB2 G-protein-coupled receptors (GPCRs), representing potential therapeutic targets for neurodegenerative diseases. Cannabinoids also regulate the activity of GPR55, a recently "deorphanized" GPCR that directly interacts with CB1 and with CB2 receptors. Our hypothesis is that these heteromers may be taken as potential targets for Parkinson's disease (PD). This work aims at assessing the expression of heteromers made of GPR55 and CB1/CB2 receptors in the striatum of control and parkinsonian macaques (with and without levodopa-induced dyskinesia). For this purpose, double blind in situ proximity ligation assays, enabling the detection of GPCR heteromers in tissue samples, were performed in striatal sections of control, MPTP-treated and MPTP-treated animals rendered dyskinetic by chronic treatment with levodopa. Image analysis and statistical assessment were performed using dedicated software. We have previously demonstrated the formation of heteromers between GPR55 and CB1 receptor (CB1-GPR55_Hets), which is highly expressed in the central nervous system (CNS), but also with the CB2 receptor (CB2-GPR55_Hets). Compared to the baseline expression of CB1-GPR55_Hets in control animals, our results showed increased expression levels in basal ganglia input nuclei of MPTP-treated animals. These observed increases in CB1-GPR55_Hets returned back to baseline levels upon chronic treatment with levodopa in dyskinetic animals. Obtained data regarding CB2-GPR55_Hets were quite similar, with somehow equivalent amounts in control and dyskinetic animals, and with increased expression levels in MPTP animals. Taken together, the detected increased expression of GPR55-endocannabinoid heteromers appoints these GPCR complexes as potential non-dopaminergic targets for PD therapy.

12.
Ann N Y Acad Sci ; 1475(1): 34-42, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32594556

RESUMO

The cannabinoid CB1 receptor (CB1 R) is the most abundant G protein-coupled receptor in the central nervous system, consistent with the important role of endocannabinoids as neuromodulators. Cannabinoids also modulate the function of G protein-coupled receptor 55 (GPR55), which forms heteroreceptor complexes with the CB1 R in the striatum. The aim was to characterize cannabinoid CB1 R-GPR55 heteromers (CB1 R/GPR55Hets) in the basal ganglia input nuclei of nonhuman primates, Macaca fascicularis, both in projection neurons and interneurons, by the in situ proximity ligation assay. Striatal projecting neurons were identified by the retrograde neuroanatomical tracer, biotinylated dextran amine (BDA), injected into external or internal subdivisions of the globus pallidus. Triple immunofluorescent stains were carried out to visualize (1) BDA-labeled neurons, (2) CB1 R/GPR55Hets, and (3) striatal interneurons positive for choline acetyltransferase, parvalbumin, calretinin, or nitric oxide synthase. CB1 R/GPR55Hets were identified within both types of projection neurons as well as all interneurons except those that are cholinergic. Moreover, CB1 R/GPR55Hets were found specifically in the neuronal cell surface, and also in intracellular membranes. Further research efforts will be needed to confirm the intracellular occurrence of heteromers and their potential as therapeutic targets in diseases related to motor control imbalances, particularly within a parkinsonian context (with or without levodopa-induced dyskinesia).


Assuntos
Corpo Estriado/metabolismo , Neurônios/metabolismo , Multimerização Proteica , Receptor CB1 de Canabinoide/metabolismo , Receptores de Canabinoides/metabolismo , Animais , Anticorpos/metabolismo , Biomarcadores/metabolismo , Interneurônios/metabolismo , Macaca fascicularis , Masculino
13.
Cells ; 9(5)2020 04 26.
Artigo em Inglês | MEDLINE | ID: mdl-32357548

RESUMO

(1) Background. N-methyl d-aspartate (NMDA) ionotropic glutamate receptor (NMDAR), which is one of the main targets to combat Alzheimer's disease (AD), is expressed in both neurons and glial cells. The aim of this paper was to assess whether the adenosine A2A receptor (A2AR), which is a target in neurodegeneration, may affect NMDAR functionality. (2) Methods. Immuno-histo/cytochemical, biophysical, biochemical and signaling assays were performed in a heterologous cell expression system and in primary cultures of neurons and microglia (resting and activated) from control and the APPSw,Ind transgenic mice. (3) Results. On the one hand, NMDA and A2A receptors were able to physically interact forming complexes, mainly in microglia. Furthermore, the amount of complexes was markedly enhanced in activated microglia. On the other hand, the interaction resulted in a novel functional entity that displayed a cross-antagonism, that could be useful to prevent the exacerbation of NMDAR function by using A2AR antagonists. Interestingly, the amount of complexes was markedly higher in the hippocampal cells from the APPSw,Ind than from the control mice. In neurons, the number of complexes was lesser, probably due to NMDAR not interacting with the A2AR. However, the activation of the A2AR receptors resulted in higher NMDAR functionality in neurons, probably by indirect mechanisms. (4) Conclusions. A2AR antagonists such as istradefylline, which is already approved for Parkinson's disease (Nouriast® in Japan and Nourianz® in the US), have potential to afford neuroprotection in AD in a synergistic-like fashion. i.e., via both neurons and microglia.


Assuntos
Antagonistas do Receptor A2 de Adenosina/metabolismo , Receptor A2A de Adenosina/metabolismo , Receptores de N-Metil-D-Aspartato/metabolismo , Adenosina/metabolismo , Doença de Alzheimer/metabolismo , Animais , Ácido Glutâmico/metabolismo , Células HEK293 , Hipocampo , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Microglia/metabolismo , N-Metilaspartato/metabolismo , N-Metilaspartato/farmacologia , Neuroglia/metabolismo , Neurônios/metabolismo , Neuroproteção , Cultura Primária de Células , Receptores de N-Metil-D-Aspartato/efeitos dos fármacos , Transdução de Sinais
14.
Pharmacol Res ; 159: 104940, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32470563

RESUMO

BACKGROUND: Recent approved medicines whose active principles are Δ9Tetrahidrocannabinol (Δ9-THC) and/or cannabidiol (CBD) open novel perspectives for other phytocannabinoids also present in Cannabis sativa L. varieties. Furthermore, solid data on the potential benefits of acidic and varinic phytocannabinoids in a variety of diseases are already available. Mode of action of cannabigerol (CBG), cannabidiolic acid (CBDA), cannabigerolic acid (CBGA), cannabidivarin (CBDV) and cannabigerivarin (CBGV) is, to the very least, partial. HYPOTHESIS/PURPOSE: Cannabinoid CB1 or CB2 receptors, which belong to the G-protein-coupled receptor (GPCR) family, are important mediators of the action of those cannabinoids. Pure CBG, CBDA, CBGA, CBDV and CBGV from Cannabis sativa L. are differentially acting on CB1 or CB2 cannabinoid receptors. STUDY DESIGN: Determination of the affinity of phytocannabinoids for cannabinoid receptors and functional assessment of effects promoted by these compounds when interacting with cannabinoid receptors. METHODS: A heterologous system expressing the human versions of CB1 and/or CB2 receptors was used. Binding to membranes was measured using radioligands and binding to living cells using a homogenous time resolved fluorescence resonance energy transfer (HTRF) assay. Four different functional outputs were assayed: determination of cAMP levels and of extracellular-signal-related-kinase phosphorylation, label-free dynamic mass redistribution (DMR) and ß-arrestin recruitment. RESULTS: Affinity of cannabinoids depend on the ligand of reference and may be different in membranes and in living cells. All tested phytocannabinoids have agonist-like behavior but behaved as inverse-agonists in the presence of selective receptor agonists. CBGV displayed enhanced potency in many of the functional outputs. However, the most interesting result was a biased signaling that correlated with differential affinity, i.e. the overall results suggest that the binding mode of each ligand leads to specific receptor conformations underlying biased signaling outputs. CONCLUSION: Results here reported and the recent elucidation of the three-dimensional structure of CB1 and CB2 receptors help understanding the mechanism of action that might be protective and the molecular drug-receptor interactions underlying biased signaling.

15.
Pharmacol Res ; 158: 104801, 2020 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-32416215

RESUMO

While natural Δ9-tetrahidrocannabinol (Δ9THC), cannabidiol (CBD), and their therapeutic potential have been extensively researched, some cannabinoids have been less extensively investigated. The present article compiles data from the literature that highlight the health benefits and therapeutic potential of lesser known phytocannabinoids, which we have divided into varinic, acidic, and "minor" (i.e., cannabinoids that are not present in high quantities in common varieties of Cannabis sativa L). A growing interest in these compounds, which are enriched in some cannabis varieties, has already resulted in enough preclinical information to show that they are promising therapeutic agents for a variety of diseases. Every phytocannabinoid has a "preferential" mechanism of action, and often targets the cannabinoid receptors, CB1 and/or CB2. The recent resolution of the structure of cannabinoid receptors demonstrates the atypical nature of cannabinoid binding, and that different binding modes depend on the agonist or partial agonist/inverse agonist, which allows for differential signaling, even acting on the same cannabinoid receptor. In addition, other players and multiple signaling pathways may be targeted/engaged by phytocannabinoids, thereby expanding the mechanistic possibilities for therapeutic use.

16.
Front Aging Neurosci ; 12: 12, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32226375

RESUMO

The exact cause of Parkinson's disease (PD), the second most prevalent neurodegenerative disease in modern societies, is still unknown. Many scientists point out that PD is caused by a complex interaction between different factors. Although the main risk factor is age, there are other influences, genetic and environmental, that individually or in combination may trigger neurodegenerative changes leading to PD. Nowadays, research remains focused on better understanding which environmental factors are related to the risk of developing PD and why. In line with the knowledge on evidence on exposures that prevent/delay PD onset or that impact on disease progression, the aims of this review were: (i) to comment on the non-genetic risk factors that mainly affect idiopathic PD; and (ii) to comment on seemingly reliable preventive interventions. We discuss both environmental factors that may affect the central nervous system (CNS) or the intestinal tract, and the likely mechanisms underlying noxious or protective actions. Knowledge on risk, protective factors, and mechanisms may help to envisage why nigral dopaminergic neurons are so vulnerable in PD and, eventually, to design new strategies for PD prevention and/or anti-PD therapy. This article reviews the variety of the known and suspected environmental factors, such as lifestyle, gut microbiota or pesticide exposition, and distinguishes between those that are harmful or beneficial for the PD acquisition or progression. In fact, the review covers one of the most novel players in the whole picture, and we address the role of microbiota on keeping a healthy CNS and/or on preventing the "side-effects" related to aging.

17.
J Mol Endocrinol ; 63(4): R81-R92, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31539876

RESUMO

Addiction and eating disorders involve brain reward circuits. Binge eating predisposes to addictive behavior, while the cessation of exposure to drugs of abuse leads to reward activities, including intake of tasty foods. Cocaine use is associated with a decrease in food intake, with reversal after drug use is discontinued. Exciting new findings show that receptors for the 'hunger' hormone, ghrelin, directly interact with the sigma-1 receptor (σ1R), which is a target of cocaine. σ1Rs are key players in regulating dopaminergic neurotransmission and ghrelin-mediated actions. This review focuses on the σ1 receptor as a general neuroendocrine regulator by directly interacting with neuronal G-protein-coupled receptors. This review also covers the early mechanisms by which cocaine binding to σ1 blocks the food-seeking behavior triggered by ghrelin. Those findings appear as fundamental to understand common mechanisms in drug addiction and eating disorders.


Assuntos
Apetite/genética , Transtornos Relacionados ao Uso de Cocaína/etiologia , Receptores sigma/genética , Animais , Cálcio/metabolismo , Cocaína/metabolismo , Transtornos Relacionados ao Uso de Cocaína/metabolismo , AMP Cíclico/metabolismo , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Dopamina/metabolismo , Comportamento Alimentar , Humanos , Ligantes , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Neurônios/metabolismo , Receptores Dopaminérgicos/metabolismo , Receptores de Grelina/metabolismo , Receptores sigma/metabolismo , Recompensa , Transdução de Sinais
18.
Biochem Pharmacol ; 157: 148-158, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30194918

RESUMO

Currently, biased agonism is at the center stage of drug development approaches. We analyzed effects of a battery of cannabinoids plus/minus cannabidiol (CBD) in four functional parameters (cAMP levels, phosphorylation of extracellular signal-regulated kinases (ERK1/2), ß-arrestin recruitment and label-free/DMR) in HEK-293T cells expressing cannabinoid receptors, CB1 or CB2, or CB1-CB2 heteroreceptor complexes. In all cases two natural agonists plus two selective synthetic agonists were used. Furthermore, the effect of cannabidiol, at a dose (100 nM) that does not allow significant binding to the orthosteric center of either receptor, was measured. From the huge amount of generated data, we would like to highlight that the two psychotropic molecules (Δ9-tetrahydrocannabinol/THC and CP-55940) showed similar bias in CB1R and that the bias of THC was particularly relevant toward MAPK pathway. Furthermore, THC did not activate the Gi protein coupled to CB2R. Interestingly, the biased agonism was reduced when assays were performed in cells expressing the two receptors, thus suggesting that the heteromer allows less functional selectivity. In terms of cannabidiol action, the phytocannabinoid altered the functional responses, likely by allosteric means, and modified potency, agonist IC50/EC50 values and biased agonism in qualitative and/or quantitative different ways depending on the agonist. The effect of cannabidiol on anandamide actions on both cannabinoid receptors was particularly noteworthy as was significantly different from that of other compounds. Results are a compendium of data on biased agonism on cannabinoid receptors in the absence and presence of cannabidiol. In addition, for the first time, GPCR biased agonism is characterized in an heteromeric context.


Assuntos
Canabidiol/farmacologia , Receptor CB1 de Canabinoide/agonistas , Receptor CB2 de Canabinoide/agonistas , Canabinoides/química , Canabinoides/farmacologia , Células HEK293 , Humanos , Receptor CB1 de Canabinoide/metabolismo , Receptor CB2 de Canabinoide/metabolismo , Transdução de Sinais
19.
Front Pharmacol ; 9: 632, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29977202

RESUMO

Cannabigerol (CBG) is one of the major phytocannabinoids present in Cannabis sativa L. that is attracting pharmacological interest because it is non-psychotropic and is abundant in some industrial hemp varieties. The aim of this work was to investigate in parallel the binding properties of CBG to cannabinoid CB1 (CB1R) and CB2 (CB2R) receptors and the effects of the compound on agonist activation of those receptors and of CB1-CB2 heteroreceptor complexes. Using [3H]-CP-55940, CBG competed with low micromolar Ki values the binding to CB1R and CB2R. Homogeneous binding in living cells, which is only technically possible for the CB2R, provided a 152 nM Ki value. Also interesting, CBG competed the binding of [3H]-WIN-55,212-2 to CB2R but not to CB1R (Ki: 2.7 versus >30 µM). The phytocannabinoid modulated signaling mediated by receptors and receptor heteromers even at low concentrations of 0.1-1 µM. cAMP, pERK, ß-arrestin recruitment and label-free assays in HEK-293T cells expressing the receptors and treated with endocannabinoids or selective agonists proved that CBG is a partial agonist of CB2R. The action on cells expressing heteromers was similar to that obtained in cells expressing the CB2R. The effect of CBG on CB1R was measurable but the underlying molecular mechanisms remain uncertain. The results indicate that CBG is indeed effective as regulator of endocannabinoid signaling.

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