scholarly journals Ghrelin and Cannabinoid Functional Interactions Mediated by Ghrelin/CB1 Receptor Heteromers That Are Upregulated in the Striatum From Offspring of Mice Under a High-Fat Diet

2021 ◽  
Vol 15 ◽  
Author(s):  
Alejandro Lillo ◽  
Jaume Lillo ◽  
Iu Raïch ◽  
Cristina Miralpeix ◽  
Francesc Dosrius ◽  
...  
Keyword(s):  
High Fat Diet ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Striatal Neurons ◽  
High Fat ◽  
Receptor Complexes ◽  
Functional Interactions ◽  
Heterologous System ◽  
Receptor Heteromers ◽  
The One

There is evidence of ghrelinergic-cannabinoidergic interactions in the central nervous system (CNS) that may impact on the plasticity of reward circuits. The aim of this article was to look for molecular and/or functional interactions between cannabinoid CB1 and ghrelin GHS-R1a receptors. In a heterologous system and using the bioluminescence resonance energy transfer technique we show that human versions of cannabinoid CB1 and ghrelin GHS-R1a receptors may form macromolecular complexes. Such receptor heteromers have particular properties in terms of CB1/Gi-mediated signaling and in terms of GHS-R1a-Gq-mediated signaling. On the one hand, just co-expression of CB1R and GHS-R1a led to impairment of cannabinoid signaling. On the other hand, cannabinoids led to an increase in ghrelin-derived calcium mobilization that was stronger at low concentrations of the CB1 receptor agonist, arachidonyl-2’-chloroethylamide (ACEA). The expression of CB1-GHS-R1a receptor complexes in striatal neurons was confirmed by in situ proximity ligation imaging assays. Upregulation of CB1-GHS-R1a- receptor complexes was found in striatal neurons from siblings of pregnant female mice on a high-fat diet. Surprisingly, the expression was upregulated after treatment of neurons with ghrelin (200 nM) or with ACEA (100 nM). These results help to better understand the complexities underlying the functional interactions of neuromodulators in the reward areas of the brain.

scholarly journals Identification of the Ghrelin and Cannabinoid CB2 Receptor Heteromer Functionality and Marked Upregulation in Striatal Neurons from Offspring of Mice under a High-Fat Diet

2021 ◽  
Vol 22 (16) ◽  
pp. 8928
Author(s):  
Jaume Lillo ◽  
Alejandro Lillo ◽  
David A. Zafra ◽  
Cristina Miralpeix ◽  
Rafael Rivas-Santisteban ◽  
...  
Keyword(s):  
High Fat Diet ◽  
Cb2 Receptor ◽  
Striatal Neurons ◽  
High Fat ◽  
Proximity Ligation ◽  
Receptor Complexes ◽  
Allosteric Interactions ◽  
Heterologous System ◽  
The Central Nervous System

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.

scholarly journals Profiling novel pharmacology of receptor complexes using Receptor-HIT

2021 ◽  
Vol 49 (4) ◽  
pp. 1555-1565
Author(s):  
Elizabeth K.M. Johnstone ◽  
Kevin D.G. Pfleger
Keyword(s):  
Tyrosine Kinases ◽  
Drug Targets ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Live Cells ◽  
Reporter System ◽  
Receptor Complexes ◽  
Receptor Heteromers ◽  
Endogenous Proteins ◽  
The Individual

Many receptors are able to undergo heteromerisation, leading to the formation of receptor complexes that may have pharmacological profiles distinct from those of the individual receptors. As a consequence of this, receptor heteromers can be classed as new drug targets, with the potential for achieving greater specificity and selectivity over targeting their constituent receptors. We have developed the Receptor-Heteromer Investigation Technology (Receptor-HIT), which enables the detection of receptor heteromers using a proximity-based reporter system such as bioluminescence resonance energy transfer (BRET). Receptor-HIT detects heteromers in live cells and in real time, by utilising ligand-induced signals that arise from altered interactions with specific biomolecules, such as ligands or proteins. Furthermore, monitoring the interaction between the receptors and the specific biomolecules generates functional information about the heteromer that can be pharmacologically quantified. This review will discuss various applications of Receptor-HIT, including its use with different classes of receptors (e.g. G protein-coupled receptors (GPCRs), receptor tyrosine kinases (RTKs) and others), its use to monitor receptor interactions both intracellularly and extracellularly, and also its use with genome-edited endogenous proteins.

scholarly journals V1b and CRHR1 Receptor Heterodimerization Mediates Synergistic Biological Actions of Vasopressin and CRH

2012 ◽  
Vol 26 (3) ◽  
pp. 502-520 ◽  
Author(s):  
Brigitte Murat ◽  
Dominic Devost ◽  
Miriam Andrés ◽  
Julie Mion ◽  
Véra Boulay ◽  
...  
Keyword(s):  
Chromaffin Cells ◽  
Molecular Mechanisms ◽  
Inositol Phosphates ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Hek293 Cells ◽  
Synergistic Interactions ◽  
Heterologous System ◽  
The One ◽  
Dose Dependent

Abstract Vasopressin (AVP) and CRH synergistically regulate adrenocorticotropin and insulin release at the level of the pituitary and pancreas, respectively. Here, we first extended these AVP and CRH coregulation processes to the adrenal medulla. We demonstrate that costimulation of chromaffin cells by AVP and CRH simultaneously induces a catecholamine secretion exceeding the one induced by each hormone alone, thus demonstrating a net potentiation. To further elucidate the molecular mechanisms underlying this synergism, we coexpressed human V1b and CRH receptor (CRHR)1 receptor in HEK293 cells. In this heterologous system, AVP also potentiated CRH-stimulated cAMP accumulation in a dose-dependent and saturable manner. This effect was only partially mimicked by phorbol ester or inhibited by a phospholipase C inhibitor respectively. This finding suggests the existence of an new molecular mechanism, independent from second messenger cross talk. Similarly, CRH potentiated the AVP-induced inositol phosphates production. Using bioluminescence resonance energy transfer, coimmunoprecipitation, and receptor rescue experiments, we demonstrate that V1b and CRHR1 receptors assemble as heterodimers. Moreover, new pharmacological properties emerged upon receptors cotransfection. Taken together, these data strongly suggest that direct molecular interactions between V1b and CRHR1 receptors play an important role in mediating the synergistic interactions between these two receptors.

scholarly journals Multiple system atrophy-associated oligodendroglial protein p25α stimulates formation of novel α-synuclein strain with enhanced neurodegenerative potential

2021 ◽  
Author(s):  
Nelson Ferreira ◽  
Hjalte Gram ◽  
Zachary A. Sorrentino ◽  
Emil Gregersen ◽  
Sissel Ida Schmidt ◽  
...  
Keyword(s):  
Multiple System Atrophy ◽  
Protein Misfolding ◽  
Resonance Energy Transfer ◽  
Lewy Bodies ◽  
Resonance Energy ◽  
Alpha Synuclein ◽  
Striatal Neurons ◽  
End Stage ◽  
Intracellular Aggregates

AbstractPathology consisting of intracellular aggregates of alpha-Synuclein (α-Syn) spread through the nervous system in a variety of neurodegenerative disorders including Parkinson’s disease, dementia with Lewy bodies, and multiple system atrophy. The discovery of structurally distinct α-Syn polymorphs, so-called strains, supports a hypothesis where strain-specific structures are templated into aggregates formed by native α-Syn. These distinct strains are hypothesised to dictate the spreading of pathology in the tissue and the cellular impact of the aggregates, thereby contributing to the variety of clinical phenotypes. Here, we present evidence of a novel α-Syn strain induced by the multiple system atrophy-associated oligodendroglial protein p25α. Using an array of biophysical, biochemical, cellular, and in vivo analyses, we demonstrate that compared to α-Syn alone, a substoichiometric concentration of p25α redirects α-Syn aggregation into a unique α-Syn/p25α strain with a different structure and enhanced in vivo prodegenerative properties. The α-Syn/p25α strain induced larger inclusions in human dopaminergic neurons. In vivo, intramuscular injection of preformed fibrils (PFF) of the α-Syn/p25α strain compared to α-Syn PFF resulted in a shortened life span and a distinct anatomical distribution of inclusion pathology in the brain of a human A53T transgenic (line M83) mouse. Investigation of α-Syn aggregates in brain stem extracts of end-stage mice demonstrated that the more aggressive phenotype of the α-Syn/p25α strain was associated with an increased load of α-Syn aggregates based on a Förster resonance energy transfer immunoassay and a reduced α-Syn aggregate seeding activity based on a protein misfolding cyclic amplification assay. When injected unilaterally into the striata of wild-type mice, the α-Syn/p25α strain resulted in a more-pronounced motoric phenotype than α-Syn PFF and exhibited a “tropism” for nigro-striatal neurons compared to α-Syn PFF. Overall, our data support a hypothesis whereby oligodendroglial p25α is responsible for generating a highly prodegenerative α-Syn strain in multiple system atrophy.

scholarly journals Insect antimicrobial peptides show potentiating functional interactions against Gram-negative bacteria

2015 ◽  
Vol 282 (1806) ◽  
pp. 20150293 ◽  
Author(s):  
Mohammad Rahnamaeian ◽  
Małgorzata Cytryńska ◽  
Agnieszka Zdybicka-Barabas ◽  
Kristin Dobslaff ◽  
Jochen Wiesner ◽  
...  
Keyword(s):  
Antimicrobial Peptides ◽  
Acquired Resistance ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Gram Negative ◽  
Functional Interactions ◽  
Trade Offs ◽  
Low Concentrations ◽  
Chaperone Network ◽  
Cell Growth And Viability

Antimicrobial peptides (AMPs) and proteins are important components of innate immunity against pathogens in insects. The production of AMPs is costly owing to resource-based trade-offs, and strategies maximizing the efficacy of AMPs at low concentrations are therefore likely to be advantageous. Here, we show the potentiating functional interaction of co-occurring insect AMPs (the bumblebee linear peptides hymenoptaecin and abaecin) resulting in more potent antimicrobial effects at low concentrations. Abaecin displayed no detectable activity against Escherichia coli when tested alone at concentrations of up to 200 μM, whereas hymenoptaecin affected bacterial cell growth and viability but only at concentrations greater than 2 μM. In combination, as little as 1.25 μM abaecin enhanced the bactericidal effects of hymenoptaecin. To understand these potentiating functional interactions, we investigated their mechanisms of action using atomic force microscopy and fluorescence resonance energy transfer-based quenching assays. Abaecin was found to reduce the minimal inhibitory concentration of hymenoptaecin and to interact with the bacterial chaperone DnaK (an evolutionarily conserved central organizer of the bacterial chaperone network) when the membrane was compromised by hymenoptaecin. These naturally occurring potentiating interactions suggest that combinations of AMPs could be used therapeutically against Gram-negative bacterial pathogens that have acquired resistance to common antibiotics.

scholarly journals Supplementation of Stingless Bee Honey from Heterotrigona itama Improves Antiobesity Parameters in High-Fat Diet Induced Obese Rat Model

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Ahmad Zulkifli Mohd Rafie ◽  
Amir Syahir ◽  
Wan Amir Nizam Wan Ahmad ◽  
Mohd Zulkifli Mustafa ◽  
Abdul Razak Mariatulqabtiah
Keyword(s):  
High Fat Diet ◽  
Ldl Cholesterol ◽  
Body Weight Gain ◽  
Hdl Cholesterol ◽  
Stingless Bee ◽  
Sprague Dawley ◽  
High Fat ◽  
A Value ◽  
Sd Rats ◽  
The One

Heterotrigona itama is a common stingless bee species found in Southeast Asia. Studies on the health benefits of its honey are limited in comparison with other stingless bee species. This study examines the antiobesity benefits found in stingless bee honey (SBH) from H. itama. The parameters used to measure the benefits were weight change, morphological structures, and biochemical characteristics. The research was conducted by using rats that were given a high-fat diet (HFD). In total 48 male Sprague Dawley (SD) rats were given a formulated HFD to increase the levels of obesity, the HFD was administered with a value of 0.68 g/cm2. The duration of the treatment was six weeks, and the results show that the induction obesity using the HFD was successful. Following this, the rats were then treated with SBH (at dosages of 1000 mg/kg, 750 mg/kg or 500 mg/kg), with orlistat or with a placebo. Compared with typical obesity treatment methods, the one that used the three dosages of SBH showed a higher reduction in body mass index (BMI), percentage of body weight gain, adiposity index, and relative organ weight (ROW). The levels of liver enzymes (ALT, AST, and ALP) were also significantly lower in SBH-treated groups. The levels of triglycerides and LDL-cholesterol were significantly lower, while the level of HDL-cholesterol was significantly higher in comparison with the control obese group. In terms of morphological structures, the number of adipocyte cells was reduced, and the hepatocytes found in the liver were less prone to rupturing when treated with SBH. In conclusion, the administration of SBH led to an improvement in indicators associated with obesity reduction. SBH also possesses a hepatoprotective potential which can reduce the health risks related to obesity.

scholarly journals Adrenaline responsiveness of glucose metabolism in insulin-resistant adipose tissue of rats fed a high-fat diet

1979 ◽  
Vol 180 (2) ◽  
pp. 431-433 ◽  
Author(s):  
C Susini ◽  
M Lavau ◽  
J Herzog
Keyword(s):  
Adipose Tissue ◽  
Glucose Metabolism ◽  
Glucose Uptake ◽  
High Fat Diet ◽  
Glucose Utilization ◽  
High Fat ◽  
Glycerol Moiety ◽  
Insulin Resistant ◽  
The One ◽  
Fat Pads

The effects of adrenaline (0.5 microM) and the combination of adrenaline and insulin (1.7nM) on [6-14C]glucose metabolism were assessed in epididymal fat-pads from rats fed either a low- or high-fat diet. The response of lipolysis to adrenaline was clearly diminished in fat-fed rats. Insulin added to adrenaline inhibited the lipolysis by 50% regardless of the diet. Glucose utilization in adipose tissue of fat-fed rats was markedly stimulated by adrenaline (glucose uptake was increased 3-fold and the production of CO2 and the glycerol moiety of acylglycerol was increased 4-fold). However, adipose tissue from fat-fed rats was resistant to the effect of insulin to produce a further increase in adrenaline-stimulated glucose uptake. The intracellular capacity of lipogenesis on the one hand, and the production of CO2 and the glycerol moiety of acylglycerol on the other, are of prime importance in the action of insulin and adrenaline on glucose utilization in this model.

scholarly journals Investigation of Receptor Heteromers Using NanoBRET Ligand Binding

2021 ◽  
Vol 22 (3) ◽  
pp. 1082
Author(s):  
Elizabeth K. M. Johnstone ◽  
Heng B. See ◽  
Rekhati S. Abhayawardana ◽  
Angela Song ◽  
K. Johan Rosengren ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Ligand Binding ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Receptor Heteromers ◽  
Intracellular Proteins ◽  
Β2 Adrenergic Receptor ◽  
First Time

Receptor heteromerization is the formation of a complex involving at least two different receptors with pharmacology that is distinct from that exhibited by its constituent receptor units. Detection of these complexes and monitoring their pharmacology is crucial for understanding how receptors function. The Receptor-Heteromer Investigation Technology (Receptor-HIT) utilizes ligand-dependent modulation of interactions between receptors and specific biomolecules for the detection and profiling of heteromer complexes. Previously, the interacting biomolecules used in Receptor-HIT assays have been intracellular proteins, however in this study we have for the first time used bioluminescence resonance energy transfer (BRET) with fluorescently-labeled ligands to investigate heteromerization of receptors on the cell surface. Using the Receptor-HIT ligand binding assay with NanoBRET, we have successfully investigated heteromers between the angiotensin II type 1 (AT1) receptor and the β2 adrenergic receptor (AT1-β2AR heteromer), as well as between the AT1 and angiotensin II type 2 receptor (AT1-AT2 heteromer).

scholarly journals Gene Expression in Livers of BALB/C and C57BL/6J Mice Fed a High-Fat Diet

2011 ◽  
Vol 40 (1) ◽  
pp. 71-82 ◽  
Author(s):  
Satomi Nishikawa ◽  
Jiro Sugimoto ◽  
Miyoko Okada ◽  
Tetsuya Sakairi ◽  
Shiro Takagi
Keyword(s):  
Gene Expression ◽  
Fatty Acid ◽  
Mrna Expression ◽  
High Fat Diet ◽  
Fatty Acid Uptake ◽  
Blood Chemistry ◽  
Acid Uptake ◽  
High Fat ◽  
Hepatic Lipid Accumulation ◽  
The One

We previously demonstrated that high-fat diet (HFD)–induced hepatic lipid accumulation is more severe in BALB/c mice than in C57BL/6J (B6) mice. To understand the changes in liver metabolism, we studied blood chemistry, gene expression, and histopathological changes of the liver in nine-week HFD-fed BALB/c and B6 mice and one- or four-week HFD-fed BALB/c mice. Serum total cholesterol and triglyceride levels were significantly increased in all HFD-fed groups, and one- and four-week HFD-fed BALB/c groups, respectively. Histopathology revealed that vacuolation of hepatocytes was severe in nine-week HFD-fed BALB/c mice, although it was less severe in the other groups. Microarray analysis of mRNA expression of nine-week HFD-fed BALB/c mice showed up-regulation of genes involved in fatty acid uptake and biosynthesis, such as Cd36, Acaca, Acly, and Fasn. Some changes were observed in the one- and four-week HFD-fed BALB/c groups and the nine-week HFD-fed B6 group, however these changes in mRNA expression were not so marked. In conclusion, the fatty accumulation observed in BALB/c mice may be caused, at least in part, by up-regulation of fatty acid uptake and biosynthesis. Cd36, Acaca, Acly and Fasn may be involved in these metabolic processes.

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