Search Results (183)

Intracellular emetic signals involved in the cannabinoid CB₁ receptor inverse agonist/antagonist SR141716A were investigated. SR141716A (20 mg/kg, i.p.)-evoked vomiting occurred via both the central and peripheral mechanisms. This was accompanied by robust emesis-associated increases in the following: (i) c-fos- and phospho-glycogen synthase kinase-3α/β (p-GSK-3αβ)-expression in the shrew’s dorsal vagal complex (DVC), (ii) phospho-extracellular signal-regulated kinase1/2 (p-ERK_1/2) expression in both the DVC and jejunal enteric nervous system, and (iii) time-dependent upregulation of cAMP levels and phosphorylation of protein kinase A (PKA), protein kinase B (Akt), GSK-3α/β, ERK_1/2, and protein kinase C αβII (PKCαβII) in the brainstem. SR141716A-evoked emetic parameters were attenuated by diverse inhibitors of the following: PKA, ERK_1/2, GSK-3, phosphatidylinositol 3-kinase (PI3K)-Akt pathway, phospholipase C (PLC), PKC, Ca²⁺/calmodulin-dependent protein kinase II (CaMKII), L-type Ca²⁺ channel (LTCC), store-operated Ca²⁺ entry (SOCE), inositol trisphosphate receptor (IP3R), ryanodine receptor (RyRs), both 5-HT₃-, and D_2/3-receptor antagonists, and the transient receptor potential vanilloid 1 receptor (TRPV1R) agonist. SR141716A appears to evoke vomiting via inverse agonist activity involving emesis-associated kinases, including cAMP/PKA, ERK_1/2, PI3K/Akt/GSK-3, PLC/PKCαβII, and CaMKII, which depend upon Ca²⁺ mobilization linking extracellular Ca²⁺ entry via plasma membrane Ca²⁺ channels (LTCC, SOCE, TRIPV1R) and intracellular Ca²⁺ release via IP3Rs and RyRs. The 5-HT₃, NK₁, and D_2/3 receptors also contribute to SR141716A-mediated vomiting. Full article

Obesity is a complex, multifactorial disease and a growing global health challenge associated with type 2 diabetes, cardiovascular disorders, cancer, and reduced quality of life. The existing pharmacological therapies are characterized by their limited number and efficacy, and safety concerns further restrict their utilization. This review synthesizes extensive knowledge regarding the role of the endocannabinoid system (ECS) in the pathogenesis of obesity, as well as its potential as a therapeutic target. A thorough evaluation of preclinical and clinical data concerning endocannabinoid ligands, cannabinoid receptors (CB1, CB2), their genetic variants, and pharmacological interventions targeting the ECS was conducted. Literature data suggests that the overactivation of the ECS may play a role in the pathophysiology of excessive food intake, dysregulated energy balance, adiposity, and metabolic disturbances. The pharmacological modulation of ECS components, by means of CB1 receptor antagonists/inverse agonists, CB2 receptor agonists, enzyme inhibitors, and hybrid or allosteric ligands, has demonstrated promising anti-obesity effects in animal models. However, the translation of these findings into clinical practice remains challenging due to safety concerns, particularly neuropsychiatric adverse events. The development of novel strategies, including peripherally restricted compounds, hybrid dual-target agents, dietary modulation of endocannabinoid tone, and non-pharmacological interventions, promises to advance the field of obesity management. Full article

Estrogen-related receptor γ (ERRγ) has been reported to regulate various inflammation-related diseases. Herein, we attempted to evaluate the effects of DN200434 as a modulator for ERRγ in mice with atopic dermatitis (AD). Levels of mRNA and protein expression for ERRγ were evaluated in normal and DNCB-induced AD-diagnosed skin. The effects of DN200434 on the chemokines, inflammatory cytokines, and AKT/MAPK/NFκB pathway signaling were investigated in TNF-α/IFN-γ-treated HaCaT cells. DNCB-induced AD mice received DN200434 intraperitoneally for 10 days. Epidermal thickness at the dorsal aspect of the inflamed skin, spleen index, serum IgE levels, and proinflammatory cytokine levels in the skin lesions were measured. Histopathological evaluations, including assessments of epidermal hyperplasia, dermal inflammation, hyperkeratosis, folliculitis, and mast cell counts, were performed to confirm diagnostic features. Significant elevations in ERRγ expression at the RNA and protein levels were observed in DNCB-induced AD lesions. DN200434 suppressed chemokine and inflammatory cytokine expression and inhibited the elevated phosphorylation levels of AKT, ERK, p38, and NFκB in TNF-α/IFN-γ-treated HaCaT cells. Treatment with DN200434 alleviated DNCB-induced AD symptoms. The histopathological score and levels of infiltrated mast cells were also markedly lower in DN200434-treated AD mice than in vehicle-treated AD mice. Consistently, DN200434 reduced the serum IgE level and mRNA expression of TNFα and IL-6 in AD-diagnosed lesions. Collectively, our findings indicated the feasibility of ERRγ as a therapeutic target for the regulation of AD and that DN200434 can be a useful therapeutic agent in treating AD. Full article

Background: While mRNA vaccines effectively limit hospitalization and severe COVID-19 disease, the precise early innate immune mechanisms associated with their efficacy and reactogenicity remain underexplored. The identification of innate immune correlates prior to vaccination could provide mechanistic insights and potentially predict responses. Methods: We developed an in vitro model to study the innate immune activation of pre-vaccination peripheral blood mononuclear cells (PBMCs) collected from participants enrolled in a well-characterized COVID-19 BioNTech/Pfizer BNT162b2 vaccine (BNT162b2 vaccine) cohort. Pre-vaccination PBMCs were stimulated with empty lipid nanoparticle (LNP), mRNA-LNP, or Toll-like receptor (TLR) agonists. Using multiparameter spectral flow cytometry, we analyzed the baseline immune state, innate responsiveness to stimuli, and cytokine profiles of study participants. These pre-vaccination in vitro results were analyzed for correlations with post-vaccination symptoms and spike-specific IgG responses. Results: Baseline dendritic cell (DC) states inversely correlated with the magnitude of symptoms following BNT162b2 vaccination. Heightened conventional (cDC) and weaker plasmacytoid DC (pDC) responses to RNA stimuli correlated with the magnitude of an acute IgG response. IgG durability modestly correlated with a lower pDC state but higher cDC2 and monocyte baseline states and inversely correlated with TLR3 agonist responsiveness. Conclusions: The pre-vaccination assessment of innate immune function and resting states can be used to fit models potentially predictive of immunogenicity and reactogenicity to BNT162b2 vaccination. Pre-vaccination DC states may influence reactogenicity, while the response to RNA may impact antibody responses. Our data suggest that pre-vaccination assessment offers insights into the innate mechanisms driving mRNA vaccine responses and has predictive potential. Full article

Cannabinoid receptor 1 (CB₁) signalling is critical for weight gain and for milk intake in newborn pups. This is important as in humans, low birth weight increases the risk for attention-deficit hyperactivity disorder (ADHD). Moreover, some children with ADHD also have Tourette syndrome (TS). However, it remains unclear if insufficient CB₁ receptor signalling may promote ADHD/TS-like behaviours. Here, ADHD/TS-like behaviours were studied from postnatal to adulthood by exposing postnatal wild-type CB₁ and Cannabinoid receptor 2 (CB₂) knockout mouse pups to SR141716A (rimonabant), a CB₁ receptor antagonist/inverse agonist. Postnatal disruption of the cannabinoid system by SR141716A induced vocal-like tics and learning deficits in male mice, accompanied by excessive vocalisation, hyperactivity, motor-like tics and/or high-risk behaviour in adults. In CB₁ knockouts, rearing and risky behaviours increased in females. In CB₂ knockouts, vocal-like tics did not develop, and males were hyperactive with learning deficits. Importantly, females were hyperactive but showed no vocal-like tics. The appearance of vocal-like tics depends on disrupted CB₁ receptor signalling and on functional CB₂ receptors after birth. Inhibition of CB₁ receptor signalling together with CB₂ receptor stimulation underlie ADHD/TS-like behaviours in males. This study suggests that the ADHD/TS phenotype may be a single clinical entity resulting from incorrect cannabinoid signalling after birth. Full article

Recent bioassay studies have unexpectedly supported the high (computationally predicted) binding affinities of angiotensin receptor blockers (ARBs) at α-adrenergic receptors (αARs) in isolated smooth muscle. Computational predictions from ligand docking studies are consistent with very low concentrations of ARBs (e.g., sartans or bisartans) that partially reduce (20–50%) the contractile response to phenylephrine, suggesting that some ARBs may function as partial inverse agonists at αARs. Virtual ligand screening (docking) and molecular dynamics (MD) simulations were carried out to explore the binding affinities and stabilities of selected non-peptide ligands (e.g., ARBs and small-molecule opioids) for several G-protein coupled receptor (GPCR) types, including angiotensin II (AngII) type 1 receptor (AT₁R), α1AR, α2AR, and μ-(µOR) and ժ-opioid receptors (ժOR). Results: All ligands docked preferentially to the binding pocket on the cell surface domain of the GPCR types investigated. Drug binding was characterized by weak interactions (hydrophobic, hydrogen bonding, pi-pi) and stronger ionic and salt-bridge interactions (cation-pi and cation-anion interactions). Ligands specific to each GPCR category showed considerable cross-binding with alternative GPCRs, with small-molecule medications appearing less selective than their peptide or ARB functional equivalents. ARBs that exhibit higher affinities for AT₁R also demonstrate higher affinities for µORs and ժORs than opiate ligands, such as fentanyl and naltrexone. Moreover, ARBs had a higher affinity for αARs than either alpha agonists (epinephrine and phenylephrine) or inhibitors (prazosin and doxazosin). MD simulations of membrane-embedded ARB-GPCR complexes proved stable over nanosecond time scales and suggested that some ARBs may behave as agonists or antagonists depending on the GPCR type. Based on the results presented in this and related investigations, we propose that agonists bind to the resting A-site of GPCRs, while inverse agonists occupy the desensitizing D-site, which partial agonists like morphine and fentanyl share, contributing to addiction. ARBs block both AngII and alpha receptors, suggesting that they are more potent antihypertensive drugs than ACE inhibitors. ARBs have the potential to inhibit morphine tolerance and appear to disrupt receptor desensitization processes, potentially by competing at the D-site. Our results suggest the possible therapeutic potential of ARBs in treating methamphetamine and opiate addictions. Full article

The oil extract derived from black soldier fly (Hermetia illucens) larvae (BSFL) is characterized by a distinctive fatty acid composition and bioactive compounds with demonstrated anti-inflammatory properties, as shown in our previous work. The present study aims to mechanistically explore the immunomodulatory effects of a saponified form of BSFL oil (MBSFL) and its potential interaction with metabolic signaling pathways. Using Pam3CSK4-polarized M1 primary human peripheral blood mononuclear cells (PBMCs), we demonstrate that MBSFL phenotypically suppressed the secretion of pro-inflammatory cytokines TNFα, IL-6, IL-17, and GM-CSF (p < 0.01) without altering anti-inflammatory cytokine levels (TGFβ1, IL-13, and IL-4). A phosphoproteomic analysis of Pam3CSK4-stimulated THP-1 macrophages revealed MBSFL-mediated downregulation of CK2 and ERK kinases (p < 0.05), key regulators of NF-κB signaling activation. We confirmed that MBSFL directly inhibits NF-κB p65 nuclear translocation (p < 0.05), using both immunofluorescence staining and a western blot analysis of nuclear and cytoplasmic fractions. In the context of metabolism, using a luciferase reporter assay, we demonstrate that MBSFL functions as a weak agonist of PPARγ and PPARδ (p < 0.05), which are nuclear receptors involved in lipid metabolism and immune regulation. However, subsequent immunoblotting revealed a macrophage polarization-dependent regulation: MBSFL upregulated PPARγ in M0 macrophages but did not prevent its suppression upon Pam3CSK4 stimulation, whereas it specifically enhanced PPARδ expression during M1 polarization (p < 0.05). This study provides novel experimental evidence supporting our hypothesis of MBSFL’s role in immunometabolism. We demonstrate for the first time that MBSFL acts as a dual regulator by suppressing NF-κB-mediated inflammation while promoting PPARδ activity—an inverse relationship with potential relevance to immunometabolic disorders. Full article

Current treatment options for Alzheimer’s disease target neurotransmitters following the disease onset, and they offer limited efficacy without slowing down the disease progression. There has been an increasing concern in recent years targeting the histamine H3 receptor (H3R) in treating cognitive disorders, including dementia. Preclinical studies have shown that antagonists of H3R or inverse agonists enhance the cognitive function in animal models with dementia by increasing the release of neurotransmitters associated with learning and memory. This review employed a systematic literature search across databases including PubMed, Scopus, Google Scholar, and ClinicalTrials.gov, selecting peer-reviewed studies. The results of this study illustrate the complex landscape of research on H3R modulators in dementia, highlighting both promising findings and ongoing challenges in translating preclinical discoveries into effective clinical interventions. Knowing the role of H3R in dementia and developing novel pharmacological interventions targeting these receptors represent a promising avenue for future research, leading to the development of new treatments for this devastating condition. Full article

Bis-indole-derived compounds including 1,1-bis(3′-indolyl)-1-(3,5-disubstitutedphenyl)methane (DIM-3,5) analogs bind both orphan nuclear receptors 4A1 (NR4A1) and NR4A2, and DIM-3,5 compounds act as dual receptor inverse agonists and inhibit both NR4A1- and NR4A2-regulated responses. Chromatin immunoprecipitation assays show that β1-integrin and the methyltransferase gene G9a are regulated by both NR4A1 and NR4A2 acting as cofactors for Sp1- and Sp4-dependent gene expression. DIM-3,5 treatment results in the loss of one or more of these nuclear factors from the β1-integrin and G9a promoters. Single-cell and RNAseq analyses show that both receptors regulate common (<10%) and unique genes in SW480 colon cancer cells; however, functional enrichment analysis of the differentially expressed genes converges to several common pathways and gene ontology terms. Full article

Macrophages play a crucial role in maintaining intestinal homeostasis and can exhibit either pro-inflammatory M1 or anti-inflammatory M2 phenotypes. The cannabinoid receptor type 2 (CB2) is involved in immune regulation and may represent a therapeutic target in inflammatory bowel disease (IBD). Our study investigates the phenotype of circulating macrophages and CB2 expression in children with IBD, assessing the role of CB2 stimulation in macrophage polarization, iron metabolism, and intestinal barrier function. Macrophages were isolated from 17 children with ulcerative colitis (UC), 21 with Crohn’s disease (CD), and 12 healthy controls (CTR). Cells were treated with a CB2 agonist (JWH-133) and an inverse agonist (AM630). CB2 expression and macrophage polarization were assessed by Western blot. Iron metabolism was evaluated through IL-6, hepcidin levels, FPN-1 expression, and iron concentration. Inflammation was assessed by cytokine release. An in vitro “immunocompetent gut” model was used to study the effects of CB2 stimulation on macrophage polarization and intestinal barrier function. CB2 expression was reduced in IBD macrophages. Compared to controls, IBD patients showed increased M1 markers and pro-inflammatory cytokines, with a reduction in M2 markers and IL-13. Altered iron metabolism was observed, with increased [Fe³⁺], hepcidin release, and DMT1 expression, and reduced FPN-1. CB2 stimulation restored iron metabolism, induced M2 polarization, and improved intestinal barrier function. CB2 could represent a novel therapeutic target for IBD by modulating macrophage function, iron metabolism, and mucosal barrier restoration. Full article

Gastric cancer is one of the most common forms of cancer worldwide. A growing number of studies have addressed the anti-proliferative effects of cannabinoids on several tumor cells. The molecular mechanisms underlying the anti-proliferative effects of the endogenous cannabinoid anandamide (AEA) on gastric tumor cell lines have yet to be characterized. Here, we investigated the anti-proliferative mechanisms elicited by AEA on the AGS human gastric cancer cell line employing an Oncoprint database, Western blotting, and immunofluorescence. We observed that AEA (5 µM) inhibited phosphorylated AKT’s expression level. This point is relevant because AKT is mutated in AGS cells, according to Oncoprint. In addition, AEA induced the up-regulation of phosphorylated ERK and, in turn, inhibited Bcl-2 expression and activated pro-apoptotic signals induced by pro-apoptotic Bax and Bak, which resulted in caspase-3 activation. The effect of anandamide on phosphorylated AKT was dependent on cannabinoid receptor 2 activation (CB2R) as revealed by the selective inverse agonist JTE-907, which reverted the anandamide-induced expression in the phosphorylated AKT/total AKT ratio. In contrast, changes in phosphorylated ERK evoked an increase in pro-apoptotic pathways that culminated in cell death by caspase-3 activation. These results indicate that the endogenous cannabinoid anandamide in gastric cancer cells increases caspase-3 activity via mitochondrial pro-apoptotic Bax/Bak proteins and decreases viability through CB2R via AKT down-regulation’s trophic mechanisms. These effects constitute a promising tool for the design of gastric cancer therapies. Full article

Although it has been found that soccer produces limb imbalance, it has not been rigorously determined how to evaluate it in soccer players or which low-cost tests are the most effective for its analysis. Therefore, the objective of this systematic review was to identify and examine the evidence and evaluations of limb imbalance produced in professional soccer players. A systematic search was conducted in three databases (PubMed, Web of Sciences, and Scopus) to identify relevant studies published before 23 May 2022. Of the 2364 studies identified initially, only 12 articles were included in the systematic review. The results revealed that injury risks can be detected in professional soccer players through the YBT (Y Balance Test). The PSLR (Passive Straight Leg Raise) test, as well as the evaluation of the ROM (range of motion) in movements of adduction and internal hip rotation, seem to be two reliable tests to detect imbalances in the flexibility of the extremities. The FMS (Functional Motion Screen) test is inversely related to the performance in jump tests; thus, its combination can help to detect asymmetries in power generation. Finally, strength assessment tests in soccer players can negatively alter the flexibility values of agonist/antagonist muscles. Therefore, it is advisable to monitor both strength and flexibility tests synergistically to obtain a comprehensive evaluation. Full article

Liver-expressed antimicrobial peptide 2 (LEAP-2) was originally discovered as an antimicrobial peptide that plays a vital role in the host innate immune system of various vertebrates. Recent research discovered LEAP-2 as an endogenous antagonist and inverse agonist of the GHSR1a receptor. By acting as a competitive antagonist to ghrelin, LEAP-2 influences energy balance and metabolic processes via the ghrelin–GHSR1a signaling pathway. LEAP-2 alone or the LEAP-2/ghrelin molar ratio showed potential as therapeutic targets for obesity, diabetes, and metabolic disorders. This review explores the recent advances of LEAP-2 in immune modulation and energy regulation, highlighting its potential in treating the above diseases. Full article

The human nuclear receptor (NR) superfamily consists of 48 genes that are ligand-activated transcription factors that play a key role in maintaining cellular homeostasis and in pathophysiology. NRs are important drug targets for both cancer and non-cancer endpoints as ligands for these receptors can act as agonists, antagonists or inverse agonists to modulate gene expression. With two exceptions, the classical mechanism of action of NRs involves their interactions as monomers, dimers or heterodimers with their cognate response elements (cis-elements) in target gene promoters. Several studies showed that a number of NR-regulated genes did not directly bind their corresponding cis-elements and promoter analysis identified that NR-responsive gene promoters contained GC-rich sequences that bind specificity protein 1 (Sp1), Sp3 and Sp4 transcription factors (TFs). This review is focused on identifying an important sub-set of Sp-regulated genes that are indirectly coregulated through interactions with NRs. Subsequent studies showed that many NRs directly bind Sp1 (or Sp3 and Sp4), the NR/Sp complexes bind GC-rich sites to regulate gene expression and the NR acts as a ligand-modulated nuclear cofactor. In addition, several reports show that NR-responsive genes contain cis-elements that bind both Sp TFs and NRs, and mutation of either cis-element results in loss of NR-responsive (inducible and/or basal). Regulation of these genes involves interactions between DNA-bound Sp TFs with proximal or distal DNA-bound NRs, and, in some cases, other nuclear cofactors are required for gene expression. Thus, many NR-responsive genes are regulated by NR/Sp complexes, and these genes can be targeted by ligands that target NRs and also by drugs that induce degradation of Sp1, Sp3 and Sp4. Full article

Gut peptides, including glucagon-like peptide-1 (GLP-1), regulate metabolic homeostasis and have emerged as the basis for multiple state-of-the-art diabetes and obesity therapies. We previously showed that G protein-coupled receptor 17 (GPR17) is expressed in intestinal enteroendocrine cells (EECs) and modulates nutrient-induced GLP-1 secretion. However, the GPR17-mediated molecular signaling pathways in EECs have yet to be fully deciphered. Here, we expressed the human GPR17 long isoform (hGPR17L) in GLUTag cells, a murine EEC line, and we used the GPR17 synthetic agonist MDL29,951 together with pharmacological probes and genetic approaches to quantitatively assess the contribution of GPR17 signaling to GLP-1 secretion. Constitutive hGPR17L activity inhibited GLP-1 secretion, and MDL29,951 treatment further inhibited this secretion, which was attenuated by treatment with the GPR17 antagonist HAMI3379. MDL29,951 promoted both Gi/o and Gq protein coupling to mediate cyclic AMP (cAMP) and calcium signaling. hGPR17L regulation of GLP-1 secretion appeared to be Gq-independent and dependent upon Gi/o signaling, but was not correlated with MDL29,951-induced whole-cell cAMP signaling. Our studies revealed key signaling mechanisms underlying the role of GPR17 in regulating GLP-1 secretion and suggest future opportunities for pharmacologically targeting GPR17 with inverse agonists to maximize GLP-1 secretion. Full article