New clues arising from hunt of saccharides binding to galectin 3 via 3D QSAR and docking studies

Sugar mimics and their probable binding sites: design and synthesis of thiazole linked coumarin-piperazine hybrids as galectin-1 inhibitors

Sugar mimics are valuable tools in medicinal chemistry, offering the potential to overcome the limitations of carbohydrate inhibitors, such as poor pharmacokinetics and non-selectivity. In our continued efforts to develop heterocyclic galectin-1 inhibitors, we report the synthesis and characterization of thiazole-linked coumarin piperazine hybrids (10a-10i) as Gal-1 inhibitors. The compounds were characterized using 1H NMR, 13C NMR and HRMS. Among the synthesized molecules, four compounds demonstrated significant inhibitory activity, with more than 50% inhibition observed at a concentration of 20 μM in a Gal-1 enzyme assay. Fluorescence spectroscopy was further utilized to elucidate the binding constant for the synthesized compounds. 10g exhibited the highest affinity for Gal-1, with a binding constant (K a) of 9.8 × 104 M-1. To elucidate the mode of binding, we performed extensive computational analyses with 10g, including 1.2 μs all-atom molecular dynamics simulations coupled with a robust machine learning tool. Our findings indicate that 10g binds to the carbohydrate binding site of Gal-1, with the coumarin moiety playing a key role in binding interactions. Additionally, our study underscores the limitations of relying solely on docking scores for conformational selection and highlights the critical importance of performing multiple MD replicas to gain accurate insights.

Computational Study of Potential Galectin-3 Inhibitors in the Treatment of COVID-19

Galectin-3 is a carbohydrate-binding protein and the most studied member of the galectin family. It regulates several functions throughout the body, among which are inflammation and post-injury remodelling. Recent studies have highlighted the similarity between Galectin-3's carbohydrate recognition domain and the so-called "galectin fold" present on the N-terminal domain of the S1 sub-unit of the SARS-CoV-2 spike protein. Sialic acids binding to the N-terminal domain of the Spike protein are known to be crucial for viral entry into humans, and the role of Galectin-3 as a mediator of lung fibrosis has long been the object of study since its levels have been found to be abnormally high in alveolar macrophages following lung injury. In this context, the discovery of a double inhibitor may both prevent viral entry and reduce post-infection pulmonary fibrosis. In this study, we use a database of 56 compounds, among which 37 have known experimental affinity with Galectin-3. We carry out virtual screening of this database with respect to Galectin-3 and Spike protein. Several ligands are found to exhibit promising binding affinity and interaction with the Spike protein's N-terminal domain as well as with Galectin-3. This finding strongly suggests that existing Galectin-3 inhibitors possess dual-binding capabilities to disrupt Spike-ACE2 interactions. Herein we identify the most promising inhibitors of Galectin-3 and Spike proteins, of which five emerge as potential dual effective inhibitors. Our preliminary results warrant further in vitro and in vivo testing of these putative inhibitors against SARS-CoV-2 with the hope of being able to halt the spread of the virus in the future.

A Computational Perspective on Molecular Recognition by Galectins

This article presents an overview of recent computational studies dedicated to the analysis of binding between galectins and small-molecule ligands. We first present a summary of the most popular simulation techniques adopted for calculating binding poses and binding energies, and then discuss relevant examples reported in the literature for the three main classes of galectins (dimeric, tandem and chimera). We show that simulation of galectin-ligand interactions is a mature field which has proven invaluable for completing and unraveling experimental observations. Future perspectives to further improve the accuracy and cost-effectiveness of existing computational approaches will involve the development of new schemes to account for solvation and entropy effects, which represent the main current limitations to the accuracy of computational results.

An updated patent review of galectin-1 and galectin-3 inhibitors and their potential therapeutic applications (2016-present)

INTRODUCTION

Galectins are ubiquitous in nature. They have established themselves as a protein family of high therapeutic potential and play a role in a wide variety of diseases like cancer, fibrosis, and Alzheimer's. Within the galectin family, galectin- 1 and galectin- 3 have been widely studied and their roles and functions have now been well established.

AREAS COVERED

In this review, we discuss the important advancements in the development of galectin-1 & 3 inhibitors. All patents filed detailing the divergent strategies to inhibit galectin-1 & 3 from 2016 to present have been covered and discussed.

EXPERT OPINION

Over the past couple of decades, distinct galectin inhibitors have been synthesized, reported and studied. Among all, the mono and disaccharide-based antagonists have been found to be considerably successful. However, the cumbersome synthetic route followed to develop this class of inhibitors, in addition to complexity involved in making selective modifications within these molecules has posed a significant challenge. Recently, there have been numerous reports on heterocyclic-based galectin inhibitors. If these are established as potent galectin inhibitors, their ease of synthesis and tunability could overcome the potential drawbacks of carbohydrate-based inhibitors and could thus be exploited to develop efficient and highly specific galectin inhibitors.