Repurposing clinically available drugs and therapies for pathogenic targets to combat SARS-CoV-2

Construction and validation of a cell based reporter assay for identifying inhibitors of SARS coronavirus 2 RNA dependent RNA polymerase activity

Targeting RNA-dependent RNA polymerase (RdRp), a highly conserved enzyme essential for SARS coronavirus 2 (SARS-CoV-2) replication and transcription, represents a promising antiviral strategy due to its lower mutation rate than structural proteins such as Spike. This study introduces a cell-based assay system for screening potential SARS-CoV-2 RdRp inhibitors, contributing to ongoing efforts to identify effective antiviral agents. The assay utilizes a reporter vector containing the 3' untranslated region (UTR), luciferase reporter gene, and 5' UTR gene, sequentially arranged in reverse under the control of the cytomegalovirus promoter in the pcDNA3.1 vector. Co-transfection with SARS-CoV-2 RdRp resulted an increase in luminescence-based quantification of RdRp activity, achieving a Z-factor of 0.605, indicative of high reproducibility and reliability for high-throughput screening. Established RdRp inhibitors, including remdesivir, molnupiravir, tenofovir, and sofosbuvir, significantly reduced reporter activity, with remdesivir exhibiting the strongest inhibition. A newly identified RdRp inhibitor was further validated through primer extension polymerase and NMPylation assays, along with virus-based experiments, confirming its inhibitory mechanism. These results highlight the utility of this screening system in identifying effective RdRp-targeting antivirals, reinforcing the strategic importance of RdRp inhibition in combating SARS-CoV-2 and emerging variants.

Natural and Synthetic Coumarins as Potential Drug Candidates against SARS-CoV-2/COVID-19

COVID-19, an airborne disease caused by a betacoronavirus named SARS-- CoV-2, was officially declared a pandemic in early 2020, resulting in more than 770 million confirmed cases and over 6.9 million deaths by September 2023. Although the introduction of vaccines in late 2020 helped reduce the number of deaths, the global effort to fight COVID-19 is far from over. While significant progress has been made in a short period, the fight against SARS-CoV-2/COVID-19 and other potential pandemic threats continues. Like AIDS and hepatitis C epidemics, controlling the spread of COVID-19 will require the development of multiple drugs to weaken the virus's resistance to different drug treatments. Therefore, it is essential to continue developing new drug candidates derived from natural or synthetic small molecules. Coumarins are a promising drug design and development scaffold due to their synthetic versatility and unique physicochemical properties. Numerous examples reported in scientific literature, mainly by in silico prospection, demonstrate their potential contribution to the rapid development of drugs against SARS-CoV-2/COVID-19 and other emergent and reemergent viruses.

Revolutionizing Neuroimmunology: Unraveling Immune Dynamics and Therapeutic Innovations in CNS Disorders

Neuroimmunology is reshaping the understanding of the central nervous system (CNS), revealing it as an active immune organ rather than an isolated structure. This review delves into the unprecedented discoveries transforming the field, including the emerging roles of microglia, astrocytes, and the blood-brain barrier (BBB) in orchestrating neuroimmune dynamics. Highlighting their dual roles in both repair and disease progression, we uncover how these elements contribute to the intricate pathophysiology of neurodegenerative diseases, cerebrovascular conditions, and CNS tumors. Novel insights into microglial priming, astrocytic cytokine networks, and meningeal lymphatics challenge the conventional paradigms of immune privilege, offering fresh perspectives on disease mechanisms. This work introduces groundbreaking therapeutic innovations, from precision immunotherapies to the controlled modulation of the BBB using nanotechnology and focused ultrasound. Moreover, we explore the fusion of immune modulation with neuromodulatory technologies, underscoring new frontiers for personalized medicine in previously intractable diseases. By synthesizing these advancements, we propose a transformative framework that integrates cutting-edge research with clinical translation, charting a bold path toward redefining CNS disease management in the era of precision neuroimmunology.

Repurposing of antimycobacterium drugs for COVID-19 treatment by targeting SARS CoV-2 main protease: An in-silico perspective

The global mortality rate has been significantly impacted by the COVID-19 pandemic, caused by the SARS CoV-2 virus. Although the pursuit for a potent antiviral is still in progress, experimental therapies based on repurposing of existing drugs is being attempted. One important therapeutic target for COVID-19 is the main protease (Mpro) that cleaves the viral polyprotein in its replication process. Recently minocycline, an antimycobacterium drug, has been successfully implemented for the treatment of COVID-19 patients. But it's mode of action is still far from clear. Furthermore, it remains unresolved whether alternative antimycobacterium drugs can effectively regulate SARS CoV-2 by inhibiting the enzymatic activity of Mpro. To comprehend these facets, eight well-established antimycobacterium drugs were put through molecular docking experiments. Four of the antimycobacterium drugs (minocycline, rifampicin, clofazimine and ofloxacin) were selected by comparing their binding affinities towards Mpro. All of the four drugs interacted with both the catalytic residues of Mpro (His41 and Cys145). Additionally, molecular dynamics experiments demonstrated that the Mpro-minocyline complex has enhanced stability, experiences reduced conformational fluctuations and greater compactness than other three Mpro-antimycobacterium and Mpro-N3/lopinavir complexes. This research furnishes evidences for implementation of minocycline against SARS CoV-2. In addition, our findings also indicate other three antimycobacterium/antituberculosis drugs (rifampicin, clofazimine and ofloxacin) could potentially be evaluated for COVID-19 therapy.

Quinazolines and thiazolidine-2,4-dions as SARS-CoV-2 inhibitors: repurposing, in silico molecular docking and dynamics simulation

This paper presents an extensive analysis of COVID-19 with a specific focus on VEGFR-2 inhibitors as potential treatments. The investigation includes an overview of computational methodologies employed in drug repurposing and highlights in silico research aimed at developing treatments for SARS-CoV-2. The study explores the possible effects of twenty-eight established VEGFR-2 inhibitors, which include amide and urea linkers, against SARS-CoV-2. Among these, nine inhibitors exhibit highly promising in silico outcomes (designated as 3-6, 11, 24, 26, 27, and sorafenib) and are subjected to extensive molecular dynamics (MD) simulations to evaluate the binding modes and affinities of these inhibitors to the SARS-CoV-2 Mpro across a 100 ns timeframe. Additionally, MD simulations are conducted to ascertain the binding free energy of the most compelling ligand-pocket complexes identified through docking studies. The findings provide valuable understanding regarding the dynamic and thermodynamic properties of the interactions between ligands and pockets, reinforcing the outcomes of the docking studies and presenting promising prospects for the creation of therapeutic treatments targeting COVID-19.