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Nutrients Aug 2021Diet is considered an important trigger in inflammatory bowel diseases (IBD), as feeding habits can affect intestinal permeability and clearance of bacterial antigens,...
Diet is considered an important trigger in inflammatory bowel diseases (IBD), as feeding habits can affect intestinal permeability and clearance of bacterial antigens, consequently influencing the immune system. Free fatty acid receptors (FFARs), expressed on the intestinal epithelial cells, belong to the family of luminal-facing receptors that are responsive to nutrients. The objective of this study was to characterize the anti-inflammatory activity and the effect on intestinal barrier function of synthetic FFAR agonists in mouse models of colitis. Therapeutic activity of GW9508 (FFAR1 agonist), 4-CMTB (FFAR2 agonist), AR420626 (FFAR3 agonist), and GSK137647 (FFAR4 agonist) was investigated in two models of semi-chronic colitis: induced by trinitrobenzenesulfonic acid (TNBS), mimicking Crohn's disease, as well as induced by dextran sulfate sodium (DSS), which recapitulates ulcerative colitis in humans. Moreover, we assessed the influence of FFARs agonists on epithelial ion transport and measured the ion flow stimulated by forskolin and veratridine. Administration of FFAR4 agonist GSK137647 attenuated both TNBS-induced and DSS-induced colitis in mice, as indicated by macroscopic parameters and myeloperoxidase activity. The action of FFAR4 agonist GSK137647 was significantly blocked by pretreatment with selective FFAR4 antagonist AH7614. Moreover, FFAR1 and FFAR4 agonists reversed the increase in the colon permeability caused by inflammation. FFAR4 restored the tight junction genes expression in mouse colon. This is the first evaluation of the anti-inflammatory activity of selective FFAR agonists, showing that pharmacological intervention targeting FFAR4, which is a sensor of medium and long chain fatty acids, attenuates intestinal inflammation.
Topics: Aniline Compounds; Animals; Anti-Inflammatory Agents; Caco-2 Cells; Colitis; Colon; Cytokines; Dextran Sulfate; Disease Models, Animal; Humans; Inflammation Mediators; Intestinal Mucosa; Macrophages; Male; Mice; Mice, Inbred C57BL; Nitric Oxide; Permeability; RAW 264.7 Cells; Receptors, G-Protein-Coupled; Sulfonamides; Tight Junction Proteins; Tight Junctions; Trinitrobenzenesulfonic Acid
PubMed: 34444876
DOI: 10.3390/nu13082716 -
International Journal of Molecular... Aug 2021Progress in understanding peroxisome proliferator-activated receptor (PPAR) subtypes as nuclear receptors that have pleiotropic effects on biological responses has... (Review)
Review
Progress in understanding peroxisome proliferator-activated receptor (PPAR) subtypes as nuclear receptors that have pleiotropic effects on biological responses has enabled the exploration of new subtype-selective PPAR ligands. Such ligands are useful chemical biology/pharmacological tools to investigate the functions of PPARs and are also candidate drugs for the treatment of PPAR-mediated diseases, such as metabolic syndrome, inflammation and cancer. This review summarizes our medicinal chemistry research of more than 20 years on the design, synthesis, and pharmacological evaluation of subtype-selective PPAR agonists, which has been based on two working hypotheses, the ligand superfamily concept and the helix 12 (H12) holding induction concept. X-ray crystallographic analyses of our agonists complexed with each PPAR subtype validate our working hypotheses.
Topics: Animals; Binding Sites; Butyrates; Drug Discovery; Humans; Hydrocarbons, Fluorinated; Ligands; Models, Molecular; Molecular Docking Simulation; Molecular Dynamics Simulation; Molecular Structure; Peroxisome Proliferator-Activated Receptors; Protein Binding; Protein Isoforms; Structure-Activity Relationship
PubMed: 34502131
DOI: 10.3390/ijms22179223 -
Toxicological Sciences : An Official... Oct 2020Concentration/dose addition is widely used for compounds that act by similar mechanisms. But it cannot make predictions for mixtures of full and partial agonists for...
Concentration/dose addition is widely used for compounds that act by similar mechanisms. But it cannot make predictions for mixtures of full and partial agonists for effect levels above that of the least efficacious component. As partial agonists are common, we developed generalized concentration addition, which has been successfully applied to systems in which ligands compete for a single binding site. Here, we applied a pharmacodynamic model for a homodimer receptor system with 2 binding sites, the androgen receptor, that acts according to the classic homodimer activation model: Each cytoplasmic monomer protein binds ligand, undergoes a conformational change that relieves inhibition of dimerization, and binds to DNA response elements as a dimer. We generated individual dose-response data for full (dihydroxytestosterone, BMS564929) and partial (TFM-4AS-1) agonists and a competitive antagonist (MDV3100) using reporter data generated in the MDA-kb2 cell line. We used the Schild method to estimate the binding affinity of MDV3100. Data for individual compounds fit the homodimer pharmacodynamic model well. In the presence of a full agonist, the partial agonist had agonistic effects at low effect levels and antagonistic effects at high levels, as predicted by pharmacological theory. The generalized concentration addition model fits the empirical mixtures data-full/full agonist, full/partial agonist, and full agonist/antagonist-as well or better than relative potency factors or effect summation. The ability of generalized concentration addition to predict the activity of mixtures of different types of androgen receptor ligands is important as a number of environmental compounds act as partial androgen receptor agonists or antagonists.
Topics: Androgens; Binding Sites; Ligands; Receptors, Androgen
PubMed: 32726424
DOI: 10.1093/toxsci/kfaa108 -
Molecules (Basel, Switzerland) Jun 2021We recently reported on a potent synthetic agent, 135H11, that selectively targets the receptor tyrosine kinase, EphA2. While 135H11 possesses a relatively high binding...
We recently reported on a potent synthetic agent, 135H11, that selectively targets the receptor tyrosine kinase, EphA2. While 135H11 possesses a relatively high binding affinity for the ligand-binding domain of EphA2 (Kd~130 nM), receptor activation in the cell required the synthesis of dimeric versions of such agent (namely 135H12). This was expected given that the natural ephrin ligands also need to be dimerized or clustered to elicit agonistic activity in cell. In the present report we investigated whether the agonistic activity of 135H11 could be enhanced by biotin conjugation followed by complex formation with streptavidin. Therefore, we measured the agonistic EphA2 activity of 135H11-biotin (147B5) at various agent/streptavidin ratios, side by side with 135H12, and a scrambled version of 147B5 in pancreatic- and breast-cancer cell lines. The (147B5)-streptavidin complexes (when = 2, 3, 4, but not when = 1) induced a strong receptor degradation effect in both cell lines compared to 135H12 or the (scrambled-147B5)-streptavidin complex as a control, indicating that multimerization of the targeting agent resulted in an increased ability to cause receptor clustering and internalization. Subsequently, we prepared an Alexa-Fluor-streptavidin conjugate to demonstrate that (147B5)-AF-streptavidin, but not the scrambled equivalent complex, concentrates in pancreatic and breast cancers in orthotopic nude-mouse models. Hence, we conclude that these novel targeting agents, with proper derivatization with imaging reagents or chemotherapy, can be used as diagnostics, and/or to deliver chemotherapy selectively to EphA2-expressing tumors.
Topics: Animals; Binding Sites; Biotin; Breast Neoplasms; Cell Line, Tumor; Female; Humans; Ligands; Mice; Pancreatic Neoplasms; Protein Binding; Receptor, EphA2; Streptavidin
PubMed: 34204178
DOI: 10.3390/molecules26123687 -
Research and Practice in Thrombosis and... Feb 2023A state-of-the-art lecture titled "Preeclampsia and Platelet Procoagulant Membrane Dynamics" was presented at the International Society on Thrombosis and Haemostasis...
A state-of-the-art lecture titled "Preeclampsia and Platelet Procoagulant Membrane Dynamics" was presented at the International Society on Thrombosis and Haemostasis (ISTH) Congress in 2022. Platelet activation is involved in the pathophysiology of preeclampsia and contributes to the prothrombotic state of the disorder. Still, it remains unclear what mechanisms initiate and sustain platelet activation in preeclampsia and how platelets drive the thrombo-hemorrhagic abnormalities in preeclampsia. Here, we highlight our findings that platelets in preeclampsia are preactivated possibly by plasma procoagulant agonist(s) and overexpress facilitative glucose transporter-3 (GLUT3) in addition to GLUT1. Preeclampsia platelets are also partially degranulated, procoagulant, and proaggregatory and can circulate as microaggregates/microthrombi. However, in response to exposed subendothelial collagen, such as in injured vessels during cesarean sections, preeclampsia platelets are unable to mount a full procoagulant response, contributing to blood loss perioperatively. The overexpression of GLUT3 or GLUT1 may be monitored alone or in combination (GLUT1/GLUT3 ratio) as a biomarker for preeclampsia onset, phenotype, and progression. Studies to further understand the mediators of the platelet activation and procoagulant membrane dynamics in preeclampsia can reveal novel drug targets and suitable alternatives to aspirin for the management of prothrombotic tendencies in preeclampsia. Finally, we summarize relevant new data on this topic presented during the 2022 ISTH Congress.
PubMed: 36923708
DOI: 10.1016/j.rpth.2023.100075 -
Frontiers in Endocrinology 2020G protein coupled receptors (GPCRs) can lead to G protein and non-G protein initiated signals. By virtue of its structural property, the TSH receptor (TSHR) has a unique...
G protein coupled receptors (GPCRs) can lead to G protein and non-G protein initiated signals. By virtue of its structural property, the TSH receptor (TSHR) has a unique ability to engage different G proteins making it highly amenable to selective signaling. In this study, we describe the identification and characterization of a novel small molecule agonist to the TSHR which induces primary engagement with G. To identify allosteric modulators inducing selective signaling of the TSHR we used a transcriptional-based luciferase assay system with CHO-TSHR cells stably expressing response elements (CRE, NFAT, SRF, or SRE) that were capable of measuring signals emanating from the coupling of G , G, G, and G, respectively. Using this system, TSH activated G , G, and G but not G. On screening a library of 50K molecules at 0.1,1.0 and 10 μM, we identified a novel G agonist (named MSq1) which activated G mediated NFAT-luciferase >4 fold above baseline and had an EC= 8.3 × 10 M with only minor induction of G and cAMP. Furthermore, MSq1 is chemically and structurally distinct from any of the previously reported TSHR agonist molecules. Docking studies using a TSHR transmembrane domain (TMD) model indicated that MSq1 had contact points on helices H1, H2, H3, and H7 in the hydrophobic pocket of the TMD and also with the extracellular loops. On co-treatment with TSH, MSq1 suppressed TSH-induced proliferation of thyrocytes in a dose-dependent manner but lacked the intrinsic ability to influence basal thyrocyte proliferation. This unexpected inhibitory property of MSq1 could be blocked in the presence of a PKC inhibitor resulting in derepressing TSH induced protein kinase A (PKA) signals and resulting in the induction of proliferation. Thus, the inhibitory effect of MSq1 on proliferation resided in its capacity to overtly activate protein kinase C (PKC) which in turn suppressed the proliferative signal induced by activation of the predomiant cAMP-PKA pathway of the TSHR. Treatment of rat thyroid cells (FRTL5) with MSq1 did not show any upregulation of gene expression of the key thyroid specific markers such as thyroglobulin(Tg), thyroid peroxidase (Tpo), sodium iodide symporter (Nis), and the TSH receptor (Tshr) further suggesting lack of involvement of MSq1 and G activation with cellular differentation. In summary, we identified and characterized a novel G agonist molecule acting at the TSHR and which showed a marked anti-proliferative ability. Hence, Gq biased activation of the TSHR is capable of ameliorating the proliferative signals from its orthosteric ligand and may offer a therapeutic option for thyroid growth modulation.
Topics: Animals; CHO Cells; Cell Proliferation; Cricetulus; GTP-Binding Proteins; Molecular Docking Simulation; Protein Binding; Receptors, Thyrotropin; Signal Transduction; Thyroid Epithelial Cells
PubMed: 32676053
DOI: 10.3389/fendo.2020.00372 -
Molecules (Basel, Switzerland) Aug 2022Transient receptor potential vanilloid 1 (TRPV1) is a non-selective cation channel, predominantly expressed in a subset of peripheral sensory neurons for pain signaling....
Transient receptor potential vanilloid 1 (TRPV1) is a non-selective cation channel, predominantly expressed in a subset of peripheral sensory neurons for pain signaling. Topical application of agonist capsaicin for desensitizing TRPV1 currents has been approved for relief of chronic pain. However, the potent TRPV1 capsaicin is not ingestible and even topical capsaicin causes common side effects such as skin irritation, swelling, erythema and pruritus, suggesting that a mild TRPV1 agonist might be helpful for reducing side effects while reliving pain. In this study, we reported on a partial and selective TRPV1 agonist 4-(5-chloropyridin-2-yl)--(1-indazol-6-yl)piperazine-1-carboxamide named that was modified based on targeting the residue Arg557, important for conversion between the channel antagonism and agonism. Whole-cell patch clamp recordings indicated a concentration-dependent activation of TRPV1 currents by with an EC of 1.56 ± 0.13 μM. The maximum efficacy of (30 μM) was about 60% of saturated capsaicin (10 μM). Repetitive additions of caused TRPV1 current desensitization in both TRPV1-expressing HEK293 cells and dorsal root ganglion (DRG) sensory neurons. Oral administration of dose-dependently alleviated inflammatory pain in mice. Further site-directed mutagenesis combined with molecular docking revealed that residue Arg557 is critical for TRPV1 activation by . Taken together, we identified a novel partial and selective TRPV1 agonist that exhibits antinociceptive activity in mice.
Topics: Animals; Capsaicin; Ganglia, Spinal; HEK293 Cells; Humans; Mice; Molecular Docking Simulation; Pain; Sensory Receptor Cells; TRPV Cation Channels
PubMed: 36080196
DOI: 10.3390/molecules27175428 -
ACS Chemical Biology May 2022Recent clinical trials have revealed that the chimeric peptide hormones simultaneously activating glucagon-like peptide-1 receptor (GLP-1R) and glucose-dependent...
Recent clinical trials have revealed that the chimeric peptide hormones simultaneously activating glucagon-like peptide-1 receptor (GLP-1R) and glucose-dependent insulinotropic polypeptide receptor (GIPR) demonstrate superior efficacy in glycemic control and body weight reduction, better than those activating the GLP-1R alone. However, the linear peptide-based GLP-1R/GIPR dual agonists are susceptible to proteolytic cleavage by common digestive enzymes present in the gastrointestinal tract and thus not suitable for oral administration. Here, we report the design and synthesis of biaryl-stapled peptides, with and without fatty diacid attachment, that showed potent GLP-1R/GIPR dual agonist activities. Compared to a linear peptide dual agonist and semaglutide, the biaryl-stapled peptides displayed drastically improved proteolytic stability against the common digestive enzymes. Furthermore, two stapled peptides showed excellent efficacy in an oral glucose tolerance test in mice, owing to their potent receptor activity in vitro and good pharmacokinetics exposure upon subcutaneous injection. By exploring a more comprehensive set of biaryl staplers, we expect that this stapling method could facilitate the design of the stapled peptide-based dual agonists suitable for oral administration.
Topics: Animals; Gastric Inhibitory Polypeptide; Glucagon-Like Peptide-1 Receptor; Mice; Peptides; Receptors, G-Protein-Coupled; Receptors, Gastrointestinal Hormone
PubMed: 35417146
DOI: 10.1021/acschembio.2c00175 -
The Journal of Pharmacology and... Aug 2020δ-Opioid receptor (-receptor) agonists produce antihyperalgesia, antidepressant-like effects, and convulsions in animals. However, the role of agonist efficacy in...
δ-Opioid receptor (-receptor) agonists produce antihyperalgesia, antidepressant-like effects, and convulsions in animals. However, the role of agonist efficacy in generating different -receptor-mediated behaviors has not been thoroughly investigated. To this end, efficacy requirements for -receptor-mediated antihyperalgesia, antidepressant-like effects, and convulsions were evaluated by comparing the effects of the partial agonist BU48 and the full agonist SNC80 and changes in the potency of SNC80 after -receptor elimination. Antihyperalgesia was measured in a nitroglycerin-induced thermal hyperalgesia assay. An antidepressant-like effect was evaluated in the forced swim test. Mice were observed for convulsions after treatment with SNC80 or the -opioid receptor partial agonist BU48. Ligand-induced G protein activation was measured by [S]guanosine 5'-O-[-thio]triphosphate binding in mouse forebrain tissue, and -receptor number was measured by [H]D-Pen-enkephalin saturation binding. BU48 produced antidepressant-like effects and convulsions but antagonized SNC80-induced antihyperalgesia and G protein activation. The potency of SNC80 was shifted to the right in -receptor heterozygous knockout mice and naltrindole-5'-isothiocyanate-treated mice, and the magnitude of potency shift differed across assays, with the largest shift occurring in the thermal hyperalgesia assay, followed by the forced swim test and then convulsion observation. Naltrindole antagonized these SNC80-induced behaviors with similar potencies, suggesting that these effects are mediated by the same type of -receptor. These data suggest that -receptor-mediated behaviors display a rank order of efficacy requirement, with antihyperalgesia having the highest requirement, followed by antidepressant-like effects and then convulsions. These findings further our understanding of the pharmacological mechanisms mediating the in vivo effects of -opioid receptor agonists. SIGNIFICANCE STATEMENT: -Opioid receptor (δ-receptor) agonists produce antihyperalgesia, antidepressant-like effects, and convulsions in animal models. This study evaluates pharmacological properties, specifically the role of agonist efficacy and receptor reserve, underlying these δ-receptor-mediated behaviors. These data suggest that δ-receptor-mediated behaviors display a rank order of efficacy requirement, with antihyperalgesia having the highest requirement, followed by antidepressant-like effects and then convulsions.
Topics: Animals; Behavior, Animal; Benzamides; Buprenorphine; Drug Partial Agonism; Mice; Naltrexone; Piperazines; Receptors, Opioid, delta
PubMed: 32467352
DOI: 10.1124/jpet.119.262717 -
Scientific Reports Apr 2021Although several potent bile acid Farnesoid X receptor (FXR) and Takeda G-protein-coupled receptor 5 (TGR5, GPBAR1) dual agonists such as INT-767 have been reported, no...
Although several potent bile acid Farnesoid X receptor (FXR) and Takeda G-protein-coupled receptor 5 (TGR5, GPBAR1) dual agonists such as INT-767 have been reported, no non-bile acid FXR/TGR5 dual agonist has been investigated to date. Therefore, we attempted to discover potent non-bile acid FXR/TGR5 dual agonists and identified some non-bile acid FXR/TGR5 dual agonists, such as isonicotinamide derivatives in vitro assay. Compound 20p was evaluated in C57BL/6J mice, that were administered a choline-deficient, L-amino acid-defined, high-fat diet (CDAHFD) consisting of 60 kcal% fat and 0.1% methionine by weight for one week. Compound 20p dose-dependently induced small heterodimer partner (SHP) mRNA and decreased cytochrome P450 7A1 (CYP7A1) in the liver at 10 and 30 mg/kg, respectively, which were used as FXR agonist markers. Compound 20p significantly increased the plasma levels of GLP-1 as a TGR5 agonist, and a high concentration of GLP-1 lowered blood glucose levels. We confirmed that compound 20p was a non-bile acid FXR/TGR5 dual agonist.
Topics: Animals; Cholesterol 7-alpha-Hydroxylase; Drug Discovery; Glucagon-Like Peptide 1; Liver; Male; Mice; Mice, Inbred C57BL; Pharmaceutical Preparations; RNA-Binding Proteins; Receptors, G-Protein-Coupled
PubMed: 33911126
DOI: 10.1038/s41598-021-88493-0