APOE4: A Culprit for the Vulnerability of COVID-19 in Alzheimer's Patients.

Apolipoprotein E4 (APOE4) is one of the primary genetic risk factors for late-onset of Alzheimer's disease (AD). While its primary function is to transport cholesterol, it also regulates metabolism, aggregation, and deposition of amyloid-ß (Aß) in the brain. The disruption in the generation and removal of Aß in the brain is the primary cause of memory and cognitive loss and thus plays a significant role in the development of AD. In several prior genetic investigations, the APOE4 allele has been linked to higher susceptibility to severe acute respiratory syndrome (SARSCoV- 2) infection and COVID-19 mortality. However, information on the involvement of APOE4 in the underlying pathology and clinical symptoms is limited. Due to the high infection and mortality rate of COVID-19 in AD individuals, challenges have been identified in the management of AD patients during the COVID-19 pandemic. In order to provide evidence-based, more effective healthcare, it is critical to identify underlying concerns and, preferably, biomarkers. The risk variant APOE4 imparts enhanced infectivity by the underlying coronavirus SARS-CoV-2 at a cellular level, genetic level, and route level. Here we review existing advances in clinical and basic research on the AD-related gene APOE, as well as the role of APOE in AD pathogenesis, using neurobiological evidence. Moreover, the role of APOE in severe COVID-19 in Alzheimer's patients has also been reviewed.

Computational Approaches in the Discovery and Development of Thera-peutic and Prophylactic Agents for Viral Diseases

Over the last two decades computational technologies have always played a crucial role in anti-viral drug development. Whenever a virus spreads and becomes a threat to global health it brings along the challenge to develop new therapeutics and prophylactics. Computational drug and vaccine discovery have evolved at a breakneck pace over the years. Some interesting examples of computational drug discovery are anti-AIDS drugs, where HIV protease and reverse transcriptase have been targeted by agents developed using computational methods. Various computational methods that have been applied to anti-viral research include, ligand-based methods that rely on known active compounds i.e., pharmacophore modeling, machine learning or classical QSAR; structure-based methods that rely on an experimentally determined 3D structure of the targets i.e., molecular docking and molecular dynamics and methods for development of vaccines such as reverse vaccinology; structural vaccinology and vaccine epitope prediction. In this review we summarize these approaches as they were applied to battle viral diseases and underscore their importance for anti-viral research. We discuss the role of computational methods in the development of small molecules and vaccines against, human immunodeficiency virus, yellow fever, human papilloma virus, SARS-CoV-2, and other viruses. Various computational tools available for abovementioned purposes have been listed and described. A discussion on application of artificial intelligence-based methods for antiviral drug discovery has also been included.

Potential Papain-like Protease Inhibitors Against COVID-19: A Comprehensive In Silico Based Review.

The entire world has been in a battle against the COVID-19 pandemic since its first appearance in December 2019. Thus researchers are desperately working to find an effective and safe therapeutic agent for its treatment. The multifunctional coronavirus enzyme papain-like protease (PLpro) is a potential target for drug discovery to combat the ongoing pandemic responsible for cleavage of the polypeptide, deISGylation, and suppression of host immune response. The present review collates the in silico studies performed on various FDA-approved drugs, chemical compounds, and phytochemicals from various drug databases and represents the compounds possessing the potential to inhibit PLpro. Thus this review can provide quick access to a potential candidate to medicinal chemists to perform in vitro and in vivo experiments who are thriving to find the effective agents for the treatment of COVID-19.

Potential Candidates against COVID-19 Targeting RNA-Dependent RNA Polymerase: A Comprehensive Review.

Due to the extremely contagious nature of SARS-COV-2, it presents a significant threat to humans worldwide. A plethora of studies are going on all over the world to discover the drug to fight SARS-COV-2. One of the most promising targets is RNA-dependent RNA polymerase (RdRp), responsible for viral RNA replication in host cells. Since RdRp is a viral enzyme with no host cell homologs, it allows the development of selective SARS-COV-2 RdRp inhibitors. A variety of studies used in silico approaches for virtual screening, molecular docking, and repurposing of already existing drugs and phytochemicals against SARS-COV-2 RdRp. This review focuses on collating compounds possessing the potential to inhibit SARS-COV-2 RdRp based on in silico studies to give medicinal chemists food for thought so that the existing drugs can be repurposed for the control and treatment of ongoing COVID-19 pandemic after performing in vitro and in vivo experiments.