E-pharmacophore-based screening of mGluR5 negative allosteric modulators for central nervous system disorder

Metabotropic glutamate receptors (mGluRs) in epileptogenesis: an update on abnormal mGluRs signaling and its therapeutic implications

Epilepsy is a neurological disorder characterized by high morbidity, high recurrence, and drug resistance. Enhanced signaling through the excitatory neurotransmitter glutamate is intricately associated with epilepsy. Metabotropic glutamate receptors (mGluRs) are G protein-coupled receptors activated by glutamate and are key regulators of neuronal and synaptic plasticity. Dysregulated mGluR signaling has been associated with various neurological disorders, and numerous studies have shown a close relationship between mGluRs expression/activity and the development of epilepsy. In this review, we first introduce the three groups of mGluRs and their associated signaling pathways. Then, we detail how these receptors influence epilepsy by describing the signaling cascades triggered by their activation and their neuroprotective or detrimental roles in epileptogenesis. In addition, strategies for pharmacological manipulation of these receptors during the treatment of epilepsy in experimental studies is also summarized. We hope that this review will provide a foundation for future studies on the development of mGluR-targeted antiepileptic drugs.

Discovery of novel TMPRSS2 inhibitors for COVID-19 using in silico fragment-based drug design, molecular docking, molecular dynamics, and quantum mechanics studies

The global expansion of COVID-19 and the mutations of severe acute respiratory syndrome coronavirus necessitate quick development of treatment and vaccination. Because the androgen-responsive serine protease TMPRSS2 is involved in cleaving the SARS-CoV-2 spike protein allowing the virus to enter the cell, therefore, direct TMPRSS2 inhibition will inhibit virus activation and disease progression which make it an important target for drug discovery. In this study, a homology model of TMPRSS2 protein was initially developed. Then, we used the fragment-based drug design (FBDD) technique to develop effective TMPRSS2 inhibitors. Over a half-million fragments from the enamine database were screened for their binding ability to target protein, and then best-scoring fragments were linked to building new molecules with a good binding affinity. XP docking and MM-GBSA studies revealed 10 new formed molecules with docking score ≤ -14.982 kcal/mol compared to ambroxol (control) with a docking score of -6.464 kcal/mol. Finally, molecular dynamics (MD) and density functional theory (DFT) were calculated for the top 3 molecules.

In silico virtual screening of potent inhibitor to hamper the interaction between HIV-1 integrase and LEDGF/p75 interaction using E-pharmacophore modeling, molecular docking, and dynamics simulations

The rapid increase of HIV-1 infection throughout the globe has a high demand for a superior drug with lesser side effects. LEDGF/p75, the human Lens Epithelium-Derived Growth Factor is identified as a promising cellular cofactor with integrase in facilitating the viral replication in an early stage by acting as a tethering factor in the pre-integration to the chromatin. Therefore, the present study was designed to identify a potent inhibitor by applying an E-pharmacophore based virtual screening, molecular docking, and dynamics simulation approaches. Finally, ZINC22077550 and ZINC32124441 were best identified potent molecules with the efficient binding affinity, strong hydrogen bonding, and acceptable pharmacological properties to hamper the interaction between integrase and LEDGF/p75. Further, the DFT and MDS studies were also analyzed, and shown a favorable energetic state and dynamic stability then reference compound. In conclusion, we suggest that these findings could be novel therapeutics in the future and may increase the lifespan of individuals suffering from viral infection.

Does genetic mouse model of constitutive Hint1 deficiency exhibit schizophrenia-like behaviors?

The histidine triad nucleotide binding protein 1 (HINT1) is closely related to many neuropsychiatric disorders. Clinical studies supported that mutations in the Hint1 gene correlated potentially with schizophrenia. In addition, Hint1 gene knockout (KO) mice exhibited hyperactivity induced by amphetamine and apomorphine. However, it is still unclear whether this animal model exhibits schizophrenia-like behaviors and, if so, their underlying mechanisms remain to be elucidated. Thus, our study sought to evaluate schizophrenia-like behaviors in Hint1-KO mice, and explore the associated changes in neuronal structural plasticity and schizophrenia-related molecules. A series of behavioral tests were used to compare Hint1-KO and their wild-type (WT) littermates, alongside a number of morphological and molecular biological methods. Relative to WT mice, Hint1-KO mice exhibited reduced social interaction behaviors, aggressive behavior, sensorimotor gating deficits, apathetic and self-neglect behaviors, and increased MK-801-induced hyperactivity. Hint1-KO mice also showed partly increased dendritic complexity in the hippocampus (Hip) relative to WT mice. Total glutamate was decreased in the medial prefrontal cortex, nucleus accumbens (NAc), and Hip of KO mice. Expression of NR₁, NR_2A, and D₄R was decreased whereas that of D₁R was increased in the NAc of KO relative to WT mice. The expression level of NR_2B was increased whereas that of D₁R was decreased in the Hip of KO mice. Hint1-KO mice exhibited schizophrenia-like behaviors. Partly increased dendritic complexity and dysfunction in both the dopaminergic and glutamatergic systems may be involved in the abnormalities in Hint1-KO mice.

Identification of Potential Dual Negative Allosteric Modulators of Group I mGluR Family: A Shape Based Screening, ADME Prediction, Induced Fit Docking and Molecular Dynamics Approach Against Neurodegenerative Diseases

BACKGROUND

Glutamate is the principal neurotransmitter in the human brain that exerts its effects through ionotropic glutamate receptors (iGluRs) and metabotropic glutamate receptors (mGluRs). The mGluRs are a class of C GPCRs that play a vital role in various neurobiological functions, mGluR1 and mGluR5 are the two receptors distributed throughout the brain involved in cognition, learning, memory, and other important neurological processes. Dysfunction of these receptors can cause neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, X-fragile syndrome, anxiety, depression, etc., hence these receptors are high profile targets for pharmaceutical industries.

OBJECTIVE

The objective of our study is to find the novel dual negative allosteric modulators to regulate both mGluR1 and mGluR5.

METHODS

In this study, shape screening protocol was used to find the dual negative allosteric modulators for both mGluR1 and mGluR5 followed by ADME prediction, induced-fit docking (IFD) and molecular dynamics simulations. Further, DFT analysis and MESP studies were carried out for the selected compounds.

RESULTS

Around 247 compounds were obtained from the eMolecules database and clustered through the CANVAS module and filtered with ADME properties. Furthermore, IFD revealed that the top four compounds (16059796, 25004252, 4667236 and 11670690) having good protein-ligand interactions and binding free energies. The molecular electrostatic potential of the top compounds shows interactions in the amine group and the oxygen atom in the negative potential regions. Finally, molecular dynamics simulations were performed with all the selected as well as the reported compound 29 indicates that the screened hits have better stability of protein ligand complex.

CONCLUSION

Hence, from the results, it is evident that top hits 16059796, 25004252, 4667236 and 11670690 could be a novel and potent dual negative allosteric modulators for mGluR1 and mGluR5.

The role of water and protein flexibility in the structure-based virtual screening of allosteric GPCR modulators: an mGlu5 receptor case study

Stabilizing unique receptor conformations, allosteric modulators of G-protein coupled receptors (GPCRs) might open novel treatment options due to their new pharmacological action, their enhanced specificity and selectivity in both binding and signaling. Ligand binding occurs at intrahelical allosteric sites and involves significant induced fit effects that include conformational changes in the local protein environment and water networks. Based on the analysis of available crystal structures of metabotropic glutamate receptor 5 (mGlu₅) we investigated these effects in the binding of mGlu₅ receptor negative allosteric modulators. A large set of retrospective virtual screens revealed that the use of multiple protein structures and the inclusion of selected water molecules improves virtual screening performance compared to conventional docking strategies. The role of water molecules and protein flexibility in ligand binding can be taken into account efficiently by the proposed docking protocol that provided reasonable enrichment of true positives. This protocol is expected to be useful also for identifying intrahelical allosteric modulators for other GPCR targets.

Computational Drug Design Applied to the Study of Metabotropic Glutamate Receptors

Metabotropic glutamate (mGlu) receptors are a family of eight GPCRs that are attractive drug discovery targets to modulate glutamate action and response. Here we review the application of computational methods to the study of this family of receptors. X-ray structures of the extracellular and 7-transmembrane domains have played an important role to enable structure-based modeling approaches, whilst we also discuss the successful application of ligand-based methods. We summarize the literature and highlight the areas where modeling and experiment have delivered important understanding for mGlu receptor drug discovery. Finally, we offer suggestions of future areas of opportunity for computational work.