Potent Agonist Research Articles

ORG-317 Repurposing as a Potential Agonist Targeting TMEM236 in Colorectal Cancer Treatment: Insights from Molecular Dynamics Simulation, Principal Component Analysis, and Free Energy Landscape Study.

<p> Background and objective: Colorectal Cancer (CRC) affects the colon and rectum part of the digestive system and is a significant global health concern, with approximately 1.1 million new cases annually. It ranks second in cancer-related deaths. Studies have shown future projections of CRC cases to enhance at a worrisome rate, estimating 3.2 million new cases and 1.6 million deaths worldwide by 2040. Studies have shown the downregulation of TMEM236 in CRC, and this study aimed to find the agonist to restore the function of TMEM236 via the drug repurposing method. </p><p> Methods: The different molecular and structural level analyses were performed to understand how the TMEM236 expression can be restored. To obtain the molecular level data, the following analyses were employed to understand the binding affinity and agonistic behaviour of the screened drugs: molecular docking, oral toxicity prediction, Molecular Dynamics (MD) simulation, Free Energy Landscape (FEL) analysis, and g_mmpbsa. </p><p> Results: The molecular docking, oral toxicity, and molecular interaction analyses have identified db06435, db05423, and db15197 drugs from the DrugBank database to either belong to an approved or investigational class of drugs as a potential agonist for TMEM236. The MD simulation and PCA analysis had shown db05423 (ORG-317) to exhibit stable interaction with TMEM236 protein. Similar results were obtained through FEL analysis. </p><p> Conclusion: The downregulation of TMEM236 expression and its constant binding affinity with db05423 during MD simulation suggest that this drug may restore the diminished function and expression of TMEM236. Additionally, it could function as an agonist and can be used for CRC treatment.</p>.

Concurrent intratumoural Treg cell depletion and CD8+ T cell expansion via a cleavable anti-4-1BB-interleukin-15 fusion protein.

Potent agonists of the inducible co-stimulatory receptor 4-1BB are too toxic for patients with advanced cancer. Here, on the basis of observations of a weak agonist of 4-1BB depleting regulatory T (Treg) cells within the tumour microenvironment without leading to substantial restoration of dysfunctional cytotoxic T cells (CTLs), we show that effective tumour control can be achieved via concurrent Treg cell depletion and CTL expansion through an anti-4-1BB antibody fused to interleukin-15 (IL-15) via a peptide sensitive to tumour proteases. In mouse models of advanced cancers, intraperitoneal injection of the bifunctional protein attenuated the activity of the interleukin mostly in the periphery of the primary tumour while allowing for the expansion of CTLs within the tumour microenvironment, led to more effective tumour inhibition and to lower systemic toxicity than treating the cancers with combinatorial treatment with unlinked anti-4-1BB antibody and IL-15, and reduced the resistance of tumours to checkpoint blockade. Concurrent eradication of Treg cells and activation of tumour-infiltrating lymphocytes may represent a general strategy for the effective control of advanced metastatic tumours.

Aberrant basement membrane production by HSCs in MASLD is attenuated by the bile acid analog INT-767.

The farnesoid X receptor (FXR) is a leading therapeutic target for metabolic dysfunction-associated steatohepatitis (MASH)-related fibrosis. INT-767, a potent FXR agonist, has shown promise in preclinical models. We aimed to define the mechanisms of INT-767 activity in experimental MASH and dissect cellular and molecular targets of FXR agonism in human disease. Leptin-deficient ob/ob mice were fed a MASH-inducing diet for 15 weeks before the study started. After baseline liver biopsy and stratification, mice were allocated to INT-767 (10mg/kg/d) or vehicle treatment for 8 weeks, either alongside an ongoing MASH diet (progression) or following conversion to normal chow (reversal). Effects on extracellular matrix remodeling were analyzed histologically and by RNA-sequencing. Serum fibrosis biomarkers were measured longitudinally. Human liver samples were investigated using bulk and single-cell RNA-sequencing, histology, and cell culture assays. INT-767 treatment was antifibrotic during MASH progression but not reversal, attenuating the accumulation of type I collagen and basement membrane proteins (type IV collagen and laminin). Circulating levels of PRO-C4, a type IV collagen formation marker, were reduced by INT-767 treatment and correlated with fibrosis. Expression of basement membrane constituents also correlated with fibrosis severity and adverse clinical outcomes in human MASH. Single-cell RNA-sequencing analysis of mouse and human livers, and immunofluorescence staining colocalized FXR and basement membrane expression to myofibroblasts within the fibrotic niche. Treatment of culture-activated primary human HSCs with INT-767 decreased expression of basement membrane components. These findings highlight the importance of basement membrane remodeling in MASH pathobiology and as a source of circulating biomarkers. Basement membrane deposition by activated HSCs is abrogated by INT-767 treatment and measurement of basement membrane molecules should be included when determining the therapeutic efficacy of FXR agonists.

5-HT1B receptor activation produces rapid antidepressant-like effects in rodents

Ketamine is noted for its rapid onset antidepressant response and effectiveness in patients with treatment resistant depression. While most research has focused on glutamatergic mechanisms, recent studies show that antidepressant-like effects in rodents are dependent upon the serotonergic (5-HT) system and suggest a potential contribution of the 5-HT1B receptor. In this study we utilized CP-94253 to examine whether 5-HT1B receptor agonism produces rapid and sustained antidepressant-like effects, focusing on rodent models and treatment approaches commonly used to demonstrate the differentiated response to ketamine. We first confirmed that CP-94253 is a potent 5-HT1B agonist in vitro and that CP-94253 occupies brain 5-HT1B receptors at the doses tested. CP-94253 reduced immobility in the mouse forced swim test (FST) and exhibited a prominent antidepressant signature in the mouse-behavior phenotyping platform SmartCube®. When examined 24 h after acute treatment, CP-94253 reduced FST immobility in both naïve rats and in rats receiving chronic interferon alpha treatment. Ex vivo hippocampal long-term potentiation was also enhanced in naïve rats receiving acute CP-94253 treatment, 24 h prior to the recordings. In mice exposed to chronic social defeat stress, antidepressant-like effects in the tail suspension and sucrose preference tests were seen 1 h and 24 h after acute treatment, respectively. Finally, whole brain c-fos imaging in mice showed that CP-94253 modulates neuronal activity in discrete brain regions including the lateral habenula circuit implicated in depression and the ketamine treatment response. Collectively these results support the further investigation of 5-HT1B agonism as a novel treatment approach for major depressive disorder.

Long term Coptidis Rhizoma intake induce gastrointestinal emptying inhibition and colon barrier weaken via bitter taste receptors activation in mice

BackgroundCoptidis Rhizoma, a classic bitter traditional Chinese medicine, can lead to digestive dysfunction when long-term use according to traditional experience. Bitter taste receptors have been found to regulate gastrointestinal smooth muscle contraction. Coptidis Rhizoma alkaloids are potential agonists for bitter taste receptors, but whether they can induce gastrointestinal dysfunction via bitter taste receptors is not clear. PurposeThe purpose of this study is to elucidate whether long-term Coptidis Rhizoma decoction/berberine intake can affect gastrointestinal function via bitter taste receptors. MethodsFirstly, mice were orally administered Coptidis Rhizoma decoction (or berberine) for 8 weeks, then their appetite, gastrointestinal emptying function, colon barrier function, and gut microbiota homeostasis were evaluated. Subsequently, isolated intestine, molecular docking, calcium release, and immunofluorescence co-localization experiments were applied to explore the mechanism of Coptidis Rhizoma decoction (or berberine) inhibition effects on gastrointestinal motility. Finally, transmembrane resistance, scratch assay, tight junction and cytoskeletal protein immunofluorescence staining were conducted to verify that the bitter taste receptor is the target for Coptidis Rhizoma decoction (or berberine) to damage the colon barrier function. ResultLong-term Coptidis Rhizoma decoction (or berberine) intake can reduce appetite, inhibit gastrointestinal contractions, disrupt bacterial balance and colon barrier function in mice. Further mechanistic studies have shown that the alkaloids of Coptidis Rhizoma are agonists for bitter taste receptors, which can promote α-gustducin binding to CHRM3 by activating bitter taste receptors, finally inhibiting gastrointestinal smooth muscle contraction. In addition, Coptidis Rhizoma decoction (or berberine) can activate bitter taste receptors and its downstream pathways PKCβ/RhoA/ROCK1/MLC-2, reshape skeletal proteins, downregulate tight junction protein expression, and ultimately disrupt colon barrier function. ConclusionsLong term Coptidis Rhizoma intake induce gastrointestinal emptying inhibition and colon barrier weaken via bitter taste receptor activation in mice.

The effects of chronic neuropathic pain on the self-administration of highly potent MOR agonist, fentanyl.

MOR agonists are excellent analgesics; however, they are not first-line treatments for chronic pain, in part due to abuse potential. This study demonstrates that small, significant rightward shifts in the fentanyl dose response curve were observed following induction of both sham and spared nerve injury (SNI) (chronic neuropathic pain-like) states, suggesting these changes were observed independent of pain state. These data indicate that SNI-induced neuropathic pain failed to alter the ongoing self-administration of highly potent MOR agonist, fentanyl.

Discovery of Potent Kappa Opioid Receptor Agonists Derived from Akuammicine.

Akuammicine (1), an alkaloid isolated from Picralima nitida, is an agonist of the kappa opioid receptor (κOR). To establish structure-activity relationships (SARs) for this structurally unique κOR ligand, a collection of semisynthetic derivatives was synthesized. Evaluating these derivatives for their ability to activate the κOR and mu opioid receptor (μOR) revealed key SAR trends and identified derivatives with enhanced κOR potency. Most notably, substitutions to the C10 position of the aryl ring led to a > 200-fold improvement in κOR potency and nearly complete selectivity for the κOR. A selection of the most potent ligands was shown to possess differing abilities recruitment of β-Arrestin-2 to the κOR, indicating they have distinct signaling properties from each other and existing κOR ligands. The discovery of these κOR agonists underscores the potential of using natural products to identify new classes of potent and selective ligands and provides new tools to probe the κOR.

Design, synthesis, and biological evaluation of novel highly potent FXR agonists bearing piperidine scaffold

Metabolic dysfunction-associated steatohepatitis (MASH) has become a serious threat to human health, which exhibited an increasing prevalence globally. Recently, the farnesoid X receptor (FXR) has been identified as a promising strategy for the treatment of MASH by regulating multiple pathogenesis. In this study, a new series of FXR agonists bearing piperidine scaffold was designed to reduce the high lipophilicity of the existing FXR agonists. After comprehensive multiparameter optimization, LZ-007 was discovered as a highly potent FXR agonist with suitable stability in liver microsomes of multiple species. LZ-007 exhibited highly oral bioavailability and targeted tissue exposure in the liver and ileum, while the plasma exposure is low, which might minimize the systemic side effects. Moreover, LZ-007 was significantly up-regulated the expressions of FXR and its downstream genes in the liver and ileum. In MASH model, LZ-007 exerted potent anti-MASH effects by regulating the multiple signal pathways related to lipid metabolism, oxidative stress, inflammation and fibrosis. In a 30-day toxicity study, no apparent adverse effects were observed in LZ-007 treated groups, even at the high doses of 250 and 500 mg/kg. With the positive pharmacodynamics and safety profiles, LZ-007 is worthy of further evaluation as a new anti-MASH agent.

Advancements in NMDA Receptor-Targeted Antidepressants: From d-Cycloserine Discovery to Preclinical Efficacy of Lu AF90103.

The discovery of d-cycloserine (DCS), a partial agonist of the NMDA receptor that exhibits antidepressant effects without the psychotomimetic effects of ketamine, has fueled interest in new NMDA-targeting antidepressants. Our objective was to identify potent partial agonists mirroring DCS, particularly tailored for the GluN2B subtype of the NMDA receptor. Through a structure-based drug design approach, we discovered compound 42d. This compound acts as a partial agonist of the GluN1/GluN2B complex, exhibiting 24% efficacy, and has an EC50 value of 78 nM. Subsequent investigations led us to 42e (Lu AF90103), a methyl ester prodrug of 42d capable of penetrating the blood-brain barrier, as confirmed by rat microdialysis studies. In different rat in vivo models relevant to neuropsychiatric diseases, administering 42e led to 42d demonstrating both acute effects, observed in a seizure model and EEG, and lasting effects in the stress-sensitive hippocampal pathway and an antidepressant-sensitive model.

Activating PPARβ/δ-Mediated Fatty Acid β-Oxidation Mitigates Mitochondrial Dysfunction Co-induced by Environmentally Relevant Levels of Molybdenum and Cadmium in Duck Kidneys.

Cadmium (Cd) and high molybdenum (Mo) pose deleterious effects on health. Prior studies have indicated that exposure to Mo and Cd leads to damage in duck kidneys, but limited studies have explored this damage from the perspective of fatty acid metabolism. In this study, 40 healthy 8-day-old ducks were randomly assigned to four groups and fed a basic diet containing Cd (4mg/kg Cd) or Mo (100mg/kg Mo) or both. Kidney tissues were harvested on the 16th week. Results demonstrated that Cd and/or Mo inhibited mitochondrial fatty acid β-oxidation and disrupted mitochondrial dynamics, along with significant suppression of peroxisome proliferator-activated receptor β/δ (PPARβ/δ) protein in duck kidneys. In vitro study, duck renal tubular epithelial cells were exposed for 12h to either Mo (480μM Mo), Cd (2.5μM Cd), and GW0742 (0.3μM, a potent agonist of PPARβ/δ) alone or in combination. The results demonstrated that Cd and/or Mo led to marked fatty acid oxidation deficiency and mitochondrial dysfunction and that PPARβ/δ protein was involved in the process. Altogether, this study found that activating PPARβ/δ-mediated fatty acid β-oxidation mitigates mitochondrial dysfunction co-induced by Mo and Cd in duck kidneys.

Abstract 4138674: Long-acting CRF2 receptor agonist, COR-1389, improves cardiopulmonary function in the rat model of Sugen plus hypoxia-induced pulmonary hypertension and right heart failure

Introduction: Urocortin-2 (UCN-2), a peptide which is part of the corticotropin-releasing factor (CRF) family, functions as an autocrine and paracrine factor, exerting its effects on cardiac and pulmonary function through agonism of CRF2 receptors. Although acute administration of UCN-2 has shown promise by improving heart and lung function in conditions like heart failure (HF) and pulmonary hypertension (PH), its limited stability impedes its chronic therapeutic use. Hypothesis: In this study, we explored the efficacy of COR-1389, a potent, selective and long-acting CRF2 agonist peptide, in the Sugen 5416 (VEGFR2 inhibitor, Su) combined with hypoxia (Hx) rat model of PH and right heart failure (RHF). Methods: To this aim, male adult Sprague Dawley rats were divided into three groups: Control rats (normoxia) were compared with rats injected subcutaneously with 20 mg/kg Sugen 5416 and exposed to chronic hypoxia for 3 weeks, followed by 2 weeks of normoxia. At 5 weeks, control rats and one SuHx group received subcutaneously vehicle (control and SuHx), while the third group received COR-1389 at a dose of 100 μg/kg every 4 days subcutaneously for 3 weeks (SuHx + COR-1389). At 8 weeks, cardiac and pulmonary hemodynamic functions of the three groups were evaluated using echocardiography and right heart catheterization, and heart and lung tissue were evaluated by histology and immunohistochemistry. Results: Compared to controls (n=10), SuHx exhibited increased mean pulmonary arterial pressure (mPAP), right ventricle (RV) hypertrophy (Fulton Index/body weight), muscularization of distal pulmonary arteries, RV fibrosis and cardiomyocyte hypertrophy, alongside reduced RV systolic function (Tricuspid Annular Plane Systolic Excursion, TAPSE) and cardiac output (CO). Conversely, compared to the SuHx + vehicle group (n=11), curative treatment with COR-1389 for 3 weeks in SuHx rats (n=13) led to enhanced RV systolic function (TAPSE) and CO, together with reductions in mPAP, RV hypertrophy, muscularization of pulmonary arteries, RV fibrosis and cardiomyocyte hypertrophy. Systolic blood pressure remained unchanged across all groups. Conclusion: These findings indicate that COR-1389 ameliorates the deteriorating cardiopulmonary parameters observed in the SuHx model and represents a promising approach for the treatment of PH and RHF.

The dichotomous roles of microbial-modified bile acids 7-oxo-DCA and isoDCA in intestinal tumorigenesis

The gut microbiota has a significant impact on the development and function of intestinal epithelial cells (IECs) by modifying bile acid (BA) metabolites. Recently, specific gut microbiome-derived BAs, such as 7-oxo-deoxycholic acid (7-oxo-DCA) and isodeoxycholic acid (isoDCA), have been identified to be shifted inversely in colitis and hepatic liver diseases. Although the responsible gut microbes have been identified, metabolites' effects on IECs remain largely unclear. We found that although high-fat diet treatment in mice elevated both 7-oxo-DCA and isoDCA levels, during intestinal tumorigenesis, 7-oxo-DCA levels rise while isoDCA levels decrease. Interestingly, 7-oxo-DCA promotes cancer cell growth, while isoDCA suppresses it. Moreover, 7-oxo-DCA promotes whereas isoDCA inhibits the proliferation of intestinal stem cells in organoids derived from WT and APCMin/+ mice, as well as in patient-derived colon cancer organoids. The APCMin/+ mice administered with 7-oxo-DCA heightened gut permeability and increased tumor burden, whereas isoDCA protected gut barrier and reduced tumor loads. Both BAs reshape the BA pool and shifted gut microbiome. Mechanistically, we identified 7-oxo-DCA as a natural antagonist of Farnesoid X Receptor (FXR) to downregulate FXR signaling, as opposed to isoDCA, which is a potent FXR agonist to upregulate FXR signaling. In conclusion, we unveiled the opposing roles of 7-oxo-DCA and isoDCA to promote or inhibit intestinal tumorigenesis, respectively. Manipulating the BA-FXR axis during tumor initiation and progression holds great promise for developing innovative diagnostic and therapeutic approaches for the treatment of colorectal cancer.

Plant Virus Intratumoral Immunotherapy with CPMV and PVX Elicits Durable Antitumor Immunity in a Mouse Model of Diffuse Large B-Cell Lymphoma.

Plant viruses are naturally occurring nanoparticles and adjuvants that interact with the mammalian immune system. This property can be harnessed in vaccines and immunotherapy. We have previously demonstrated that intratumoral immunotherapy with cowpea mosaic virus (CPMV) stimulates systemic and durable antitumor immunity in mouse tumor models and canine cancer patients. Here we compared the antitumor efficacy of CPMV with potato virus X (PVX) using a mouse model B-cell lymphoma (A20 and BALB/c mice). Despite their diverse morphologies and physiochemical properties, both plant viruses elicited systemic and long-lasting antitumor immune memory, preventing the recurrence of A20 lymphoma in rechallenge experiments. Data indicate differences in the underlying mechanism: CPMV persists longer in the tumor microenvironment (TME) compared to PVX; CPMV is a potent and multivalent toll-like receptor (TLR) agonist (activating TLRs 2, 4 and 7) while PVX may only weakly engage with TLR7. While CPMV and PVX recruit myeloid cells (neutrophils)─CPMV also recruits macrophages. Data further indicate that antiviral T cells may play a role in antitumor efficacy in the case of CPMV immunotherapy, however this may not be the case for PVX. Regardless of the mechanism of action, both CPMV and PVX elicited a durable antitumor response against a B-cell lymphoma tumor model and thus are intratumoral immunotherapy candidates for clinical development.

A combination of peripherally restricted CB1 and CB2 cannabinoid receptor agonists reduces bladder afferent sensitisation in cystitis

Cannabinoid agonists can potentially ameliorate lower urinary tract symptoms (LUTS), including pain associated with interstitial cystitis/bladder pain syndrome (IC/BPS). This study aims to determine the contributions of the cannabinoid 1 receptors (CB1Rs) and CB2Rs in regulating the activity of different functional classes of afferents, comparing normal healthy bladder with bladders from guinea pigs with protamine/zymosan-induced cystitis. The mechanosensitivity of different functional afferent classes was determined by ex vivo single-unit extracellular recordings.Peripherally restricted CB1R preferential agonists, ACEA and PrNMI and peripherally restricted CB2R selective agonists, 4Q3C and olorinab all reduced the mechanosensitivity of mucosal bladder afferents. The potency and efficacy of these synthetic cannabinoid agonists were significantly increased in cystitis compared to controls. Combined application of CB1R agonists, ACEA or PrNMI with the CB2R agonist, 4Q3C produced additive inhibitory effects. ACEA and PrNMI also inhibited the stretch-induced firing of high-threshold muscular bladder afferents in animals with cystitis. In contrast, low- and high-threshold muscular-mucosal bladder afferents were unaffected by the CB1R and CB2R agonists in control and cystitis. Our data indicated that peripherally restricted CB1R and CB2R agonists effectively reduce the sensitisation of probable nociceptive afferents in the bladder in cystitis. The findings also suggest a potential benefit of simultaneously targeting both the CB1Rs and CB2Rs to ameliorate LUTS in cystitis.

Invention and characterization of a systemically administered, attenuated and killed bacteria-based multiple immune receptor agonist for anti-tumor immunotherapy.

Activation of immune receptors, such as Toll-like (TLR), NOD-like (NLR) and Stimulator of Interferon Genes (STING) is critical for efficient innate and adaptive immunity. Gram-negative bacteria (G-NB) contain multiple TLR, NOD and STING agonists. Potential utility of G-NB for cancer immunotherapy is supported by observations of tumor regression in the setting of infection and Coley's Toxins. Coley reported that intravenous (i.v.) administration was likely most effective but produced uncontrollable toxicity. The discovery of TLRs and their agonists, particularly the potent TLR4 agonist lipopolysaccharide (LPS)-endotoxin, comprising ~75% of the outer membrane of G-NB, suggests that LPS may be both a critical active ingredient and responsible for dose-limiting i.v. toxicity of G-NB. This communication reports the production of killed, stabilized, intact bacteria products from non-pathogenic G-NB with ~96% reduction of LPS-endotoxin activity. One resulting product candidate, Decoy10, was resistant to standard methods of cell disruption and contained TLR2,4,8,9, NOD2 and STING agonist activity. Decoy10 also exhibited reduced i.v. toxicity in mice and rabbits, and a largely uncompromised ability to induce cytokine and chemokine secretion by human immune cells in vitro, all relative to unprocessed, parental bacterial cells. Decoy10 and a closely related product, Decoy20, produced single agent anti-tumor activity or combination-mediated durable regression of established subcutaneous, metastatic or orthotopic colorectal, hepatocellular (HCC), pancreatic, and non-Hodgkin's lymphoma (NHL) tumors in mice, with induction of both innate and adaptive immunological memory (syngeneic and human tumor xenograft models). Decoy bacteria combination-mediated regressions were observed with a low-dose, oral non-steroidal anti-inflammatory drug (NSAID), anti-PD-1 checkpoint therapy, low-dose cyclophosphamide (LDC), and/or a targeted antibody (rituximab). Efficient tumor eradication was associated with plasma expression of 15-23 cytokines and chemokines, broad induction of cytokine, chemokine, innate and adaptive immune pathway genes in tumors, cold to hot tumor inflammation signature transition, and required NK, CD4+ and CD8+ T cells, collectively demonstrating a role for both innate and adaptive immune activation in the anti-tumor immune response.

Structural mechanisms of potent lysophosphatidic acid receptor 1 activation by nonlipid basic agonists.

Lysophosphatidic acid receptor 1 (LPA1) is one of the G protein-coupled receptors activated by the lipid mediator, lysophosphatidic acid (LPA). LPA1 is associated with a variety of diseases, and LPA1 agonists have potential therapeutic value for treating obesity and depression. Although potent nonlipid LPA1 agonists have recently been identified, the mechanisms of nonlipid molecule-mediated LPA1 activation remain unclear. Here, we report a cryo-electron microscopy structure of the human LPA1-Gi complex bound to a nonlipid basic agonist, CpY, which has 30-fold higher agonistic activity as compared with LPA. Structural comparisons of LPA1 with other lipid GPCRs revealed that the negative charge in the characteristic binding pocket of LPA1 allows the selective recognition of CpY, which lacks a polar head. In addition, our structure show that the ethyl group of CpY directly pushes W2716.48 to fix the active conformation. Endogenous LPA lacks these chemical features, which thus represent the crucial elements of nonlipid agonists that potently activate LPA1. This study provides detailed mechanistic insights into the ligand recognition and activation of LPA1 by nonlipid agonists, expanding the scope for drug development targeting the LPA receptors.

Dual-function natural products: Farnesoid X receptor agonist/inflammation inhibitor for metabolic dysfunction-associated steatotic liver disease therapy

Metabolic dysfunction-associated steatotic liver disease (MASLD) is the most prevalent chronic liver disease globally, with only one Food and Drug Administration (FDA)-approved drug for its treatment. Given MASLD’s complex pathophysiology, therapies that simultaneously target multiple pathways are highly desirable. One promising approach is dual-modulation of the farnesoid X receptor (FXR), which regulates lipid and bile acid metabolism. However, FXR agonists alone are insufficient due to their limited anti-inflammatory effects. This study aimed to dto identify natural products capable of both FXR activation and inflammation inhibition to provide a comprehensive therapeutic approach for MASLD. Potential FXR ligands from the Natural Product Library were predicted via virtual screening using the Protein Preparation Wizard module in Schrodinger (2018) for molecular docking. Direct binding and regulation of candidate compounds on FXR were analyzed using surface plasmon resonance (SPR) binding assay, reporter gene analysis, and reverse transcription-polymerase chain reaction (RT-PCR). The anti-inflammatory properties of these compounds were evaluated in AML12 cells treated with tumor necrosis factor-alpha (TNF-α). Dual-function compounds with FXR agonism and inflammation inhibition were further identified in cells transfected with Fxr siRNA and treated with TNF-α. The effects of these dual-function compounds on lipid accumulation and inflammation were evaluated in cells treated with palmitic acid. Results revealed that 17 natural products were predicted via computational molecular docking as potential FXR agonists, with 15 exhibiting a strong affinity for FXR recombinant protein. Nine isoflavone compounds significantly enhanced FXR reporter luciferase activity and the mRNA expressions of Shp and Ostb. Structure-activity relationship analysis indicated that introducing isopropyl or methoxy groups at the C7 position or a methoxy group at the C6 position could enhance the agonistic efficacy of isoflavones. Three compounds (2, 6, and 8) were identified as dual-function natural products functioning as FXR agonists and inflammatory inhibitors, while one compound (12) acted as an FXR agonist to inhibit inflammation. These natural products protected hepatocytes against palmitic acid-induced lipid accumulation and inflammation. In conclusion, compounds 2, 6, and 8 (genistein, biochanin A, and 7-methoxyisoflavone, respectively) were identified as dual-function bioactive products that transactivate FXR and inhibit inflammation, serving as potential candidates or lead compounds for MASLD therapy.

Extension of impurity profiling on eltrombopag olamine to in-silico predictions: An effort to exploit correlated forced degradation products and known drug-related substances in drug discovery

The recent pandemic has highlighted the impact of diseases on global health and the economy. The rapid discovery of new hit molecules remains a tough challenge. Pharmaceutical impurity profiling can be linked to drug discovery through the identification of new hits from compounds identified during the analytical profiling. The present study demonstrates this linkage through the extension of the impurity (forced degradation) profiling of eltrombopag (ELT) olamine, a thrombopoietin (TPO) receptor agonist. The drug was exposed to standard degradation and the degradation products were primarily resolved and identified by UPLC-ESI-MS. This led to the identification of five forced degradation products (FDP). Thirty-three other known related substances (RS) of ELT, identified in the literature, were also considered. Molecular similarity checks were performed using Tanimoto/Jaccard's similarity searches. A set of structurally and topologically similar molecules, including ELT and 15 RS, was established and subjected to in-silico toxicity-, absorption-, distribution-, metabolism-, and elimination (ADME) predictions. The RS, predicted with similar or lower toxicity than ELT and a comparable ADME profile, were subjected to molecular docking to trace changes in TPO receptor affinity. The results indicated that five RS had a high Jaccard’s similarity with ELT and higher or comparable docking scores. These compounds, along with few other impurities were predicted to have lower toxicity, better or comparable absorption, distribution, metabolism, and also a better excretion profile than ELT. This justifies their entry as potential novel TPO receptor agonists in drug discovery.

Design, synthesis, and biological evaluation of evodiamine-indolequinone hybrids as novel NQO1 agonists against non-small cell lung cancer

NQO1 is a FAD containing NAD(P)H-dependent oxidoreductase that catalyzes the reduction of quinones and related substrates, which plays an important role in the treatment of non-small cell lung cancer (NSCLC). Based on the indolequinone structure from 5-methoxy-2-methylindole, the indolequinone of NQO1 agonists was first coupled with amino-evodiamine derivatives by esterification reaction, and sixteen new compounds targeting NQO1 were developed. Among them, compounds 11b and 12d (IC50 = 2.72 or 3.66 µM, respectively) were showed better activity by cytotoxicity assay than the reference drug EVO (IC50 = 19.65 µM). Furthermore, the results of flow cytometry analysis showed that compounds 11b and 12d promoted apoptosis in A549 cells, blocked the cell cycle to the G2/M stage and caused a burst of reactive oxygen species. Western blotting experiments revealed that compounds 11b and 12d, after 24 h of treatment in A549 cells, downregulate the expression of Keap1 while upregulating the expression of Nrf2, NQO1, and HO-1. This suggests that compounds 11b and 12d increase cellular antioxidant capacity by regulating the Keap1/Nrf2/NQO1 antioxidant pathway. In vivo anti-tumor experiments showed that the reference drugs EVO (TGI = 15.94 %) and 5-Fu (TGI = 27.54 %) inhibited the proliferation of tumor tissue, while compound 11b could better inhibit the proliferation of tumor tissue (TGI = 39.13 %). In conclusion, our research results suggest that compounds 11b and 12d are potent agonism of the NQO1 signaling pathway and provide a potential opportunity to improve the treatment of NSCLC.

Structure-function relationship of dynorphin B variants using naturally occurring amino acid substitutions.

Dynorphins (Dyn) represent the subset of endogenous opioid peptides with the highest binding affinity to kappa opioid receptors (KOPrs). Activation of the G-protein-coupled pathway of KOPrs has strong anticonvulsant effects. Dyn also bind to mu (MOPrs) and delta opioid receptors (DOPrs) with lower affinity and can activate the β-arrestin pathway. To fully exploit the therapeutic potential of dynorphins and reduce potential unwanted effects, increased selectivity for KOPrs combined with reduced activation of the mTOR complex would be favorable. Therefore, we investigated a series of dynorphin B (DynB) variants, substituted in one or two positions with naturally occurring amino acids for differential opioid receptor activation, applying competitive radio binding assays, GTPγS assays, PRESTO-Tango, and Western blotting on single-opioid receptor-expressing cells. Seven DynB derivatives displayed at least 10-fold increased selectivity for KOPrs over either MOPrs or DOPrs. The highest selectivity for KOPrs over MOPrs was obtained with DynB_G3M/Q8H, and the highest selectivity for KOPrs over DOPrs was obtained with DynB_L5S. Increased selectivity for KOPr over MOPr and DOPr was based on a loss of affinity or potency at MOPr and DOPr rather than a higher affinity or potency at KOPr. This suggests that the investigated amino acid exchanges in positions 3, 5, and 8 are of higher importance for binding and activation of MOPr or DOPr than of KOPr. In tests for signal transduction using the GTPγS assay, none of the DynB derivatives displayed increased potency. The three tested variants with substitutions of glycine to methionine in position 3 displayed reduced efficacy and are, therefore, considered partial agonists. The two most promising activating candidates were further investigated for functional selectivity between the G-protein and the β-arrestin pathway, as well as for activation of mTOR. No difference was detected in the respective read-outs, compared to wild-type DynB. Our data indicate that the assessment of affinity to KOPr alone is not sufficient to predict either potency or efficacy of peptidergic agonists on KOPr. Further assessment of downstream pathways is required to allow more reliable predictions of in vivo effects.