Publications by authors named "Prashant Desai"

Article Synopsis
  • Researchers successfully created an infectious clone of HSV-1 by assembling its genome from 11 cloned fragments in yeast using a method called transformation associated recombination.* -
  • They engineered mutations in five specific genes, which are important for the virus's structure and functionality, and discovered that certain combinations of these mutations led to "synthetic lethality," preventing the virus from replicating in specific cell lines.* -
  • The study focused on the mutations of the UL16 and UL21 genes, revealing that viruses lacking both proteins showed immature capsid structures unable to mature into infectious particles, highlighting their potential roles in virus assembly.*
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Background: Antiviral therapies that target herpesviruses are clinically important. Nelfinavir is a protease inhibitor that targets the human immunodeficiency virus (HIV) aspartyl protease. Previous studies demonstrated that this drug could also inhibit Kaposi's sarcoma-associated herpesvirus (KSHV) production.

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Severe acute respiratory syndrome coronavirus (SARS-CoV) is a zoonotic pathogen that can cause severe respiratory disease in humans. The new SARS-CoV-2 is the cause of the current global pandemic termed coronavirus disease 2019 (COVID-19) that has resulted in many millions of deaths world-wide. The virus is a member of the Betacoronavirus family, its genome is a positive strand RNA molecule that encodes for many genes which are required for virus genome replication as well as for structural proteins that are required for virion assembly and maturation.

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Background: Antiviral therapies that target herpesviruses are clinically important. Nelfinavir is a protease inhibitor that targets the human immunodeficiency virus (HIV) infections aspartyl protease. Previous studies demonstrated that this drug could also inhibit Kaposi's sarcoma-associated herpesvirus (KSHV) production.

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There are numerous published protocols for plaquing viruses, including references within primary literature for methodology. However, plaquing viruses can be difficult to perform, requiring focus on its specifications and refinement. It is an incredibly challenging method for new students to master, mainly because it requires meticulous attention to the most minute details.

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Herpesviruses cause severe diseases particularly in immunocompromised patients. Both genome packaging and release from the capsid require a unique portal channel occupying one of the 12 capsid vertices. Here, we report the 2.

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Macromolecules such as monoclonal antibodies (mAbs) are likely to experience poor tumor penetration because of their large size, and thus low drug exposure of target cells within a tumor could contribute to suboptimal responses. Given the challenge of inadequate quantitative tools to assess mAb activity within tumors, we hypothesized that measurement of accessible target levels in tumors could elucidate the pharmacologic activity of a mAb and could be used to compare the activity of different mAbs. Using positron emission tomography (PET), we measured the pharmacodynamics of immune checkpoint protein programmed-death ligand 1 (PD-L1) to evaluate pharmacologic effects of mAbs targeting PD-L1 and its receptor programmed cell death protein 1 (PD-1).

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Background: Limited studies have explored post-discharge outcomes following Coronavirus Disease 2019 (COVID-19) hospitalisation. We sought to characterise patients discharged following a COVID-19 hospitalisation within a large integrated health system in the United States.

Methods: We performed a retrospective study of 2180 COVID-19 patients discharged between 1 April 2020 and 31 July 2020.

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Following our observation that clofoctol led to Epstein-Barr virus (EBV) lytic gene expression upon activation of the integrated stress response (ISR), we decided to investigate the impact of AsO on viral lytic gene expression. AsO has also been reported to activate the ISR pathway by its activation of the heme-regulated inhibitor (HRI). Our investigations show that AsO treatment leads to eIF2α phosphorylation, upregulation of ATF4 and TRB3 expression, and an increase of EBV Zta gene expression in lymphoid tumor cell lines as well as in naturally infected epithelial cancer cell lines.

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Matched Molecular Pairs (MMP) analysis is a well-established technique for Structure Activity and Property Analysis (SAR and SPR). Summarizing multiple MMPs that describe the same structural change into a single chemical transform can be a powerful tool for prediction (termed Transform from here on). This is particularly useful in the area of Absorption, Distribution, Metabolism, and Elimination (ADME) analysis that is less influenced by 3D structural binding effects.

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Among the FDA-approved small molecule drugs (2005-2016) that are primarily metabolized by cytochrome P450 (CYP), 64% are primarily metabolized by CYP3A4. As the proportion of an individual drug's fraction metabolized through CYP3A4 increases, the risk for the drug to be a victim of an interaction with CYP3A4 inhibitors or inducers increases. Therefore, it is important to assess the extent of involvement of individual CYP enzymes in the overall clearance for a scaffold early in discovery and mitigate the CYP3A4-mediated victim-drug-drug interaction (DDI) risk, if warranted by the desired clinical profile of the drug.

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The viability of Mycobacterium tuberculosis (Mtb) depends on energy generated by its respiratory chain. Cytochrome bc1-aa3 oxidase and type-2 NADH dehydrogenase (NDH-2) are respiratory chain components predicted to be essential, and are currently targeted for drug development. Here we demonstrate that an Mtb cytochrome bc1-aa3 oxidase deletion mutant is viable and only partially attenuated in mice.

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The fraction unbound in the incubation, , is an important parameter to consider in the evaluation of intrinsic clearance measurements performed in hepatocytes or microsomes. Reliable estimates of based on a compound's structure have the potential to positively impact the screening timelines in drug discovery. Previous works suggested that is primarily driven by passive processes and can be described using physicochemical properties such as lipophilicity and the protonation state of the molecule.

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Several therapeutic strategies targeting Epstein-Barr virus (EBV)-associated tumors involve upregulation of viral lytic gene expression. Evidence has been presented that the unfolded protein response (UPR) leads to EBV lytic gene expression. Clofoctol, an antibacterial antibiotic, has been reported to upregulate the UPR in prostate cancer cell lines and to slow their growth.

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Human G protein-coupled receptors (GPCRs) respond to various ligands and stimuli. However, GPCRs rely on membrane for proper folding, making their biochemical properties difficult to study. By displaying GPCRs in viral envelopes, we fabricated a Virion Display (VirD) array containing 315 non-olfactory human GPCRs for functional characterization.

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Aim: Modifying the molecule's intrinsic hydrogen bond strength (HBS) is a useful approach in optimizing its permeability and P-glycoprotein (P-gp) efflux. Quantum mechanics (QM) based computation has been utilized to estimate the molecular intrinsic HBS. Despite its usefulness, the computation is time consuming for a large set of molecules.

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Deep learning has drawn significant attention in different areas including drug discovery. It has been proposed that it could outperform other machine learning algorithms, especially with big data sets. In the field of pharmaceutical industry, machine learning models are built to understand quantitative structure-activity relationships (QSARs) and predict molecular activities, including absorption, distribution, metabolism, and excretion (ADME) properties, using only molecular structures.

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Membrane proteins play vital roles in cellular signaling processes and serve as the most popular drug targets. A key task in studying cellular functions and developing drugs is to measure the binding kinetics of ligands with the membrane proteins. However, this has been a long-standing challenge because one must perform the measurement in a membrane environment to maintain the conformations and functions of the membrane proteins.

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Bacterial meningitis in neonates and infants is an acute lethal disease and occurs in response to microbial exploitation of the blood-brain barrier (BBB), resulting in the intracranial inflammation. Several pathogens, such as Escherichia coli ( E. coli), can cause this devastating disease; however, the underlying molecular mechanisms by which these pathogens exploit the BBB remain incompletely understood.

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Cre-mediated recombination is a widely used technique for the re-arrangement of DNA sequences that are bracketed by loxP recognition sites. This bacteriophage P1 enzyme is commonly used to excise the bacterial artificial chromosome (BAC) sequence, a vector sequence used for large herpesvirus genomes for the purposes of propagation and manipulation in Escherichia coli. Most methods utilize cell lines that can be induced for the expression of Cre enzyme to facilitate this excision.

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Extensive 5' untranslated regions (UTR) are a hallmark of transcripts determining hyphal morphogenesis in The major transcripts of the gene, which are responsible for cellular morphogenesis and metabolism, contain a 5' UTR of up to 1,170 nucleotides (nt). Deletion analyses of the 5' UTR revealed a 218-nt sequence that is required for production of the Efg1 protein and its functions in filamentation, without lowering the level and integrity of the transcript. Polysomal analyses revealed that the 218-nt 5' UTR sequence is required for efficient translation of the Efg1 protein.

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The organic anion-transporting polypeptide 1B1 transporter belongs to the solute carrier superfamily and is highly expressed at the basolateral membrane of hepatocytes. Several clinical studies show drug-drug interactions involving OATP1B1, thereby prompting the International Transporter Consortium to label OATP1B1 as a critical transporter that can influence a compound's disposition. To examine OATP1B1 inhibition early in the drug discovery process, we established a medium-throughput concentration-dependent OATP1B1 assay.

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