Second-Generation Dual FXR/sEH Modulators with Optimized Pharmacokinetics

Metal-Free Synthesis of 2-(per)Fluoroalkyl-3-nitro Indoles via Intramolecular Cyclization of Amides

A metal-free intramolecular cyclization of N-acyl amides for the synthesis of 3-nitro-2-(per)fluoroalkyl indoles is reported. Good functional group tolerance and a broad range of substrates are the features of this approach. The developed method is easy to operate and is suitable for the preparation of 2-difluoromethyl/trifluoromethyl/perfluoroethyl/perfluoropropyl indoles in yields of 84 to 99%. Also, the application of this protocol in the gram scale is shown.

Farnesoid X receptor: From Structure to Function and Its Pharmacology in Liver Fibrosis

The farnesoid X receptor (FXR), a ligand-activated transcription factor, plays a crucial role in regulating bile acid metabolism within the enterohepatic circulation. Beyond its involvement in metabolic disorders and immune imbalances affecting various tissues, FXR is implicated in microbiota modulation, gut-to-brain communication, and liver disease. The liver, as a pivotal metabolic and detoxification organ, is susceptible to damage from factors such as alcohol, viruses, drugs, and high-fat diets. Chronic or recurrent liver injury can culminate in liver fibrosis, which, if left untreated, may progress to cirrhosis and even liver cancer, posing significant health risks. However, therapeutic options for liver fibrosis remain limited in terms of FDA-approved drugs. Recent insights into the structure of FXR, coupled with animal and clinical investigations, have shed light on its potential pharmacological role in hepatic fibrosis. Progress has been achieved in both fundamental research and clinical applications. This review critically examines recent advancements in FXR research, highlighting challenges and potential mechanisms underlying its role in liver fibrosis treatment.

Patented Farnesoid X receptor modulators: a review (2019 - present)

INTRODUCTION

The Farnesoid X receptor (FXR) is a key transcription factor that is involved in the bile acid signaling network. The modulation of the FXR activity influences glucose and lipid homeostasis, reduces obesity and insulin resistance, as well as it regulates the pathogenesis of inflammatory and metabolic disorders. FXR ligands have therefore emerged in drug discovery as promising therapeutic agents for the prevention and treatment of gastrointestinal and liver diseases, including cancer.

AREAS COVERED

Recent advances in the field of FXR modulators are reviewed, with a particular attention on patent applications filed in the past 5 years related to both the discovery and development of FXR targeting drugs.

EXPERT OPINION

FXR agonists have proven their efficacy and safety in humans and have shown a significant potential as clinical agents to treat metabolic and inflammatory associated conditions. However, several challenges, including adverse events such as pruritus, remain to be solved. Current studies aim to gain insights into the pathophysiological mechanisms by which FXR regulates metabolism and inflammation in terms of tissue/organ/isoform-specificity, post-translational modifications and coregulatory proteins, on the route of novel, improved FXR modulators.

Moving out of CF3 -Land: Synthesis, Receptor Affinity, and in silico Studies of NK1 Receptor Ligands Containing a Pentafluorosulfanyl (SF5 ) Group

The NK1 receptor (NK1R) is a molecular target for both approved and experimental drugs intended for a variety of conditions, including emesis, pain, and cancers. While contemplating modifications to the typical NK1R pharmacophore, we wondered whether the CF3 groups common for many NK1R ligands, could be replaced with some other moiety. Our attention was drawn by the SF5 group, and so we designed, synthesized, and tested ten novel SF5 -containing compounds for NK1R affinity. All analogues exhibit detectable NK1R binding, with the best of them, compound 5 a, (3-bromo-5-(pentafluoro-λ6 -sulfanyl)benzyl acetyl-L-tryptophanate) binding only slightly worse (IC50 =34.3 nM) than the approved NK1R-targeting drug, aprepitant (IC50 =27.7 nM). Molecular docking provided structural explanation of SAR. According to our analysis, the SF5 group in our compounds occupies a position similar to that of one of the CF3 groups of aprepitant as found in the crystal structure. Additionally, we checked whether the docking scoring function or energies derived from Fragment Molecular Orbital quantum chemical calculations may be helpful in explaining and predicting the experimental receptor affinities for our analogues. Both these methods produce moderately good results. Overall, this is the first demonstration of the utility of the SF5 group in the design of NK1R ligands.

International Union of Basic and Clinical Pharmacology CXIII: Nuclear Receptor Superfamily-Update 2023

The NR superfamily comprises 48 transcription factors in humans that control a plethora of gene network programs involved in a wide range of physiologic processes. This review will summarize and discuss recent progress in NR biology and drug development derived from integrating various approaches, including biophysical techniques, structural studies, and translational investigation. We also highlight how defective NR signaling results in various diseases and disorders and how NRs can be targeted for therapeutic intervention via modulation via binding to synthetic lipophilic ligands. Furthermore, we also review recent studies that improved our understanding of NR structure and signaling. SIGNIFICANCE STATEMENT: Nuclear receptors (NRs) are ligand-regulated transcription factors that are critical regulators of myriad physiological processes. NRs serve as receptors for an array of drugs, and in this review, we provide an update on recent research into the roles of these drug targets.

Development of bile acid activated receptors hybrid molecules for the treatment of inflammatory and metabolic disorders

The farnesoid-x-receptor (FXR) and the G protein bile acid activated receptor (GPBAR)1 are two bile acid activated receptors highly expressed in entero-hepatic, immune, adipose and cardiovascular tissues. FXR and GPBAR1 are clinically validated targets in the treatment of metabolic disorders and FXR agonists are currently trialled in patients with non-alcoholic steato-hepatitis (NASH). Results of these trials, however, have raised concerns over safety and efficacy of selective FXR ligands suggesting that the development of novel agent designed to impact on multiple targets might have utility in the treatment of complex, multigenic, disorders. Harnessing on FXR and GPBAR1 agonists, several novel hybrid molecules have been developed, including dual FXR and GPBAR1 agonists and antagonists, while exploiting the flexibility of FXR agonists toward other nuclear receptors, dual FXR and peroxisome proliferators-activated receptors (PPARs) and liver-X-receptors (LXRs) and Pregnane-X-receptor (PXR) agonists have been reported. In addition, modifications of FXR agonists has led to the discovery of dual FXR agonists and fatty acid binding protein (FABP)1 and Leukotriene B4 hydrolase (LTB4H) inhibitors. The GPBAR1 binding site has also proven flexible to accommodate hybrid molecules functioning as GPBAR1 agonist and cysteinyl leukotriene receptor (CYSLTR)1 antagonists, as well as dual GPBAR1 agonists and retinoid-related orphan receptor (ROR)γt antagonists, dual GPBAR1 agonist and LXR antagonists and dual GPBAR1 agonists endowed with inhibitory activity on dipeptidyl peptidase 4 (DPP4). In this review we have revised the current landscape of FXR and GPBAR1 based hybrid agents focusing on their utility in the treatment of metabolic associated liver disorders.

In Silico Modeling and Structural Analysis of Soluble Epoxide Hydrolase Inhibitors for Enhanced Therapeutic Design

Human soluble epoxide hydrolase (sEH), a dual-functioning homodimeric enzyme with hydrolase and phosphatase activities, is known for its pivotal role in the hydrolysis of epoxyeicosatrienoic acids. Inhibitors targeting sEH have shown promising potential in the treatment of various life-threatening diseases. In this study, we employed a range of in silico modeling approaches to investigate a diverse dataset of structurally distinct sEH inhibitors. Our primary aim was to develop predictive and validated models while gaining insights into the structural requirements necessary for achieving higher inhibitory potential. To accomplish this, we initially calculated molecular descriptors using nine different descriptor-calculating tools, coupled with stochastic and non-stochastic feature selection strategies, to identify the most statistically significant linear 2D-QSAR model. The resulting model highlighted the critical roles played by topological characteristics, 2D pharmacophore features, and specific physicochemical properties in enhancing inhibitory potential. In addition to conventional 2D-QSAR modeling, we implemented the Transformer-CNN methodology to develop QSAR models, enabling us to obtain structural interpretations based on the Layer-wise Relevance Propagation (LRP) algorithm. Moreover, a comprehensive 3D-QSAR analysis provided additional insights into the structural requirements of these compounds as potent sEH inhibitors. To validate the findings from the QSAR modeling studies, we performed molecular dynamics (MD) simulations using selected compounds from the dataset. The simulation results offered crucial insights into receptor-ligand interactions, supporting the predictions obtained from the QSAR models. Collectively, our work serves as an essential guideline for the rational design of novel sEH inhibitors with enhanced therapeutic potential. Importantly, all the in silico studies were performed using open-access tools to ensure reproducibility and accessibility.

Discovery of FXR/PPARγ dual partial agonist

Farnesoid X receptor (FXR) and peroxisome proliferator-activated receptor (PPAR)γ are nuclear receptor 1 superfamily of transcription factors. FXR and PPARγ agonists have been individually investigated in clinical trial of anti-diabetic agents in the patients with nonalcoholic fatty liver disease (NAFLD). Regarding recent agonist development, the partial agonists for FXR and PPARγ are drawing attention from the standpoint of avoiding overactive responses caused by full agonists. In this article, we report that 18 with a benzimidazole scaffold possesses FXR/PPARγ dual partial agonistic activity. In addition, 18 shares the ability to reduce cyclin-dependent kinase 5-mediated phosphorylation of PPARγ-Ser273 and the metabolic stability in mouse liver microsome assay. To date, there are no published reports on FXR/PPARγ dual partial agonists with biological profiles similar to 18. Thus, the analog would be a feasible candidate as an unprecedented approach to NAFLD associated with type 2 diabetes mellitus.

Discovery of the First-in-Class Intestinal Restricted FXR and FABP1 Dual Modulator ZLY28 for the Treatment of Nonalcoholic Fatty Liver Disease

The prevalence of nonalcoholic steatohepatitis (NASH) is increasing rapidly worldwide, and NASH has become a serious problem for human health. Recently, the selective activation of the intestinal farnesoid X receptor (FXR) was considered as a more promising strategy for the treatment of NASH with lesser side effects due to reduced systemic exposure. Moreover, the inhibition of intestinal fatty acid binding protein 1 (FABP1) alleviated obesity and NASH by reducing dietary fatty acid uptake. In this study, the first-in-class intestinal restricted FXR and FABP1 dual-target modulator ZLY28 was discovered by comprehensive multiparameter optimization studies. The reduced systemic exposure of ZLY28 might provide better safety by decreasing the on- and off-target side effects in vivo. In NASH mice, ZLY28 exerted robust anti-NASH effects by inhibiting FABP1 and activating the FXR-FGF15 signaling pathway in the ileum. With the above attractive efficacy and preliminary safety profiles, ZLY28 is worthy of further evaluation as a novel anti-NASH agent.

Compilation and Evaluation of Fatty Acid Mimetics Screening Library

Focused compound libraries are well-established tools for hit identification in drug discovery and chemical probe development. We present the compilation and application of a focused screening library of fatty acid mimetics (FAMs), which are compounds designed to bind the orthosteric site proteins that endogenously accommodate natural fatty acids and lipid metabolites. This set complies with chemical properties of FAM and was found suitable for use also in cellular setting. Several hits were retrieved in screening the focused library against diverse fatty acid binding targets including the enzymes soluble epoxide hydrolase (sEH) and leukotriene A4 hydrolase (LTA4H), the nuclear receptors peroxisome proliferator-activated receptor γ (PPARγ) and retinoid X receptor α (RXRα), the carrier proteins fatty acid binding protein 4 and 5 (FABP4 and FABP5), as well as the G-protein coupled receptors leukotriene B4 receptor 1 (BLT1) and free-fatty acid receptor 1 (FFAR1). Thus, the focused FAM library is suitable to obtain chemical starting matter for fatty acid binding proteins and valuable extends available screening collections.

Soluble epoxide hydrolase inhibitors: an overview and patent review from the last decade

INTRODUCTION

Biological effects mediated by the CYP450 arm of arachidonate cascade implicate the enzyme-soluble epoxide hydrolase (sEH) in hydrolyzing anti-inflammatory epoxy fatty acids to pro-inflammatory diols. Hence, inhibiting the sEH offers a therapeutic approach to treating inflammatory diseases. Over three decades of work has shown the role of sEH inhibitors (sEHis) in treating various disorders in rodents and larger veterinary subjects. Novel chemical strategies to enhance the efficacy of sEHi have now appeared.

AREAS COVERED

A comprehensive review of patent literature related to soluble epoxide hydrolase inhibitors in the last decade (2010-2021) is provided.

EXPERT OPINION

Soluble epoxide hydrolase (sEH) is an important enzyme that metabolizes the bioactive epoxy fatty acids (EFAs) in the arachidonic acid signaling pathway and converts them to vicinal diols, which appear to be pro-inflammatory. Inhibition of sEH hence offers a mechanism to increase in vivo epoxyeicosanoid levels and resolve pro-inflammatory pathways in disease states. Significant efforts in the field have led to potent single target as well as multi-target inhibitors with promising in vitro and widely encompassing in vivo activities. Successful clinical translation of compounds targeting sEH inhibition will further validate the promised therapeutic potential of this pathway in treating human diseases.

Environmental Chemical Contribution to the Modulation of Bile Acid Homeostasis and Farnesoid X Receptor Signaling

Maintaining bile acid (BA) homeostasis is important and regulated by BA activated receptors and signaling pathways. Farnesoid X receptor (FXR) and its regulated target networks in both the liver and the intestines are critical in suppressing BA synthesis and promoting BA transport and enterohepatic circulation. In addition, FXR is critical in regulating lipid metabolism and reducing inflammation, processes critical in the development of cholestasis and fatty liver diseases. BAs are modulated by, but also control, gut microflora. Environmental chemical exposure could affect liver disease development. However, the effects and the mechanisms by which environmental chemicals interact with FXR to affect BA homeostasis are only emerging. In this minireview, our focus is to provide evidence from reports that determine the effects of environmental or therapeutic exposure on altering homeostasis and functions of BAs and FXR. Understanding these effects will help to determine liver disease pathogenesis and provide better prevention and treatment in the future. SIGNIFICANCE STATEMENT: Environmental chemical exposure significantly contributes to the development of cholestasis and nonalcoholic steatohepatitis (NASH). The impact of exposures on bile acid (BA) signaling and Farnesoid X receptor-mediated gut-liver crosstalk is emerging. However, there is still a huge gap in understanding how these chemicals contribute to the dysregulation of BA homeostasis and how this dysregulation may promote NASH development.

Design of a Potent TLX Agonist by Rational Fragment Fusion

As a master regulator of neurogenesis, the orphan nuclear receptor tailless homologue (TLX, NR2E1) maintains neuronal stem cell homeostasis by acting as a transcriptional repressor of tumor suppressor genes. It is hence considered as an appealing target for the treatment of neurodegenerative diseases, but a lack of potent TLX modulators as tools to probe pharmacological TLX control hinders further validation of its promising potential. Here, we report the development of a potent TLX agonist based on fragment screening, pharmacophore modeling, and fragment fusion. Pharmacophore similarity of a fragment screening hit and the TLX ligand ccrp2 provided a rational basis for fragment linkage, which resulted in several TLX activator scaffolds. Among them, the fused compound 10 evolved as a valuable TLX agonist tool with submicromolar potency and high selectivity over related nuclear receptors, rendering it suitable for functional studies on TLX.