A novel antibiotic class targeting the lipopolysaccharide transporter.

Carbapenem-resistant Acinetobacter baumannii (CRAB) has emerged as a major global pathogen with limited treatment options. No new antibiotic chemical class with activity against A. baumannii has reached patients in over 50 years.

Discovery of 4,5,6,7-Tetrahydropyrazolo[1.5-a]pyrizine Derivatives as Core Protein Allosteric Modulators (CpAMs) for the Inhibition of Hepatitis B Virus.

Hepatitis B Virus (HBV) core protein allosteric modulators (CpAMs) are an attractive class of potential anti-HBV therapeutic agents. Here we describe the efforts toward the discovery of a series of 4,5,6,7-tetrahydropyrazolo[1,5-]pyrazine (THPP) compounds as HBV CpAMs that effectively inhibit a broad range of nucleos(t)ide-resistant HBV variants. The lead compound demonstrated inhibition of HBV DNA viral load in a HBV AAV mouse model by oral administration.

Discovery of Linvencorvir (RG7907), a Hepatitis B Virus Core Protein Allosteric Modulator, for the Treatment of Chronic HBV Infection.

Described herein is the first-time disclosure of Linvencorvir (RG7907), a clinical compound and a hepatitis B virus (HBV) core protein allosteric modulator, for the treatment of chronic HBV infection. Built upon the core structure of hetero aryl dihydropyrimidine, RG7907 was rationally designed by combining all the drug-like features of low CYP3A4 induction, potent anti-HBV activity, high metabolic stability, low hERG liability, and favorable animal pharmacokinetic (PK) profiles. In particular, the chemistry strategy to mitigate CYP3A4 induction through introducing a large, rigid, and polar substituent at the position that has less interaction with the therapeutic biological target (HBV core proteins herein) is of general interest to the medicinal chemistry community.

Discovery of a first-in-class orally available HBV cccDNA inhibitor.

Background & Aims: The persistence of covalently closed circular DNA (cccDNA) in infected hepatocytes is the major barrier preventing viral eradication with existing therapies in patients with chronic hepatitis B. Therapeutic agents that can eliminate cccDNA are urgently needed to achieve viral eradication and thus HBV cure.

Methods: A phenotypic assay with HBV-infected primary human hepatocytes (PHHs) was employed to screen for novel cccDNA inhibitors.

Toll-Like Receptor 7 Agonist RG7854 Mediates Therapeutic Efficacy and Seroconversion in Woodchucks With Chronic Hepatitis B.

Conventional treatment of chronic hepatitis B (CHB) is rarely curative due to the immunotolerant status of patients. RG7854 is an oral double prodrug of a toll-like receptor 7 (TLR7) agonist that is developed for the treatment of CHB. The therapeutic efficacy, host immune response, and safety of RG7854 were evaluated in the woodchuck model of CHB.

Global post-translational modification profiling of HIV-1-infected cells reveals mechanisms of host cellular pathway remodeling.

Viruses must effectively remodel host cellular pathways to replicate and evade immune defenses, and they must do so with limited genomic coding capacity. Targeting post-translational modification (PTM) pathways provides a mechanism by which viruses can broadly and rapidly transform a hostile host environment into a hospitable one. We use mass spectrometry-based proteomics to quantify changes in protein abundance and two PTM types-phosphorylation and ubiquitination-in response to HIV-1 infection with viruses harboring targeted deletions of a subset of HIV-1 genes.

Host RNA quality control as a hepatitis B antiviral target.

Inhibition of the host RNA polyadenylating polymerases, PAPD5 and PAPD7 (PAPD5/7), with dihydroquinolizinone, a small orally available, molecule, results in a rapid and selective degradation of hepatitis B virus (HBV) RNA, and hence reduction in the amounts of viral gene products. DHQ, is a first in class investigational agent and could represent an entirely new category of HBV antivirals. PAPD5 and PAPD7 are non-canonical, cell specified, polyadenylating polymerases, also called terminal nucleotidyl transferases 4B and 4A (TENT4B/A), respectively.

Accelerated Preclinical Paths to Support Rapid Development of COVID-19 Therapeutics.

When SARS-CoV-2 emerged at the end of 2019, no approved therapeutics or vaccines were available. An urgent need for countermeasures during this crisis challenges the current paradigm of traditional drug discovery and development, which usually takes years from start to finish. Approaches that accelerate this process need to be considered.

The E3 Ubiquitin-Protein Ligase Cullin 3 Regulates HIV-1 Transcription.

The infectious life cycle of the human immunodeficiency virus type 1 (HIV-1) is characterized by an ongoing battle between a compendium of cellular proteins that either promote or oppose viral replication. On the one hand, HIV-1 utilizes dependency factors to support and sustain infection and complete the viral life cycle. On the other hand, both inducible and constitutively expressed host factors mediate efficient and functionally diverse antiviral processes that counteract an infection.

Efficacy of an Inhibitor of Hepatitis B Virus Expression in Combination With Entecavir and Interferon-α in Woodchucks Chronically Infected With Woodchuck Hepatitis Virus.

RG7834 is a small-molecule inhibitor of hepatitis B virus (HBV) gene expression that significantly reduces the levels of hepatitis B surface antigen (HBsAg) and HBV DNA in a humanized liver HBV mouse model. In the current study, we evaluated the potency of RG7834 in the woodchuck model of chronic HBV infection, alone and in combination with entecavir (ETV) and/or woodchuck interferon-α (wIFN-α). RG7834 reduced woodchuck hepatitis virus (WHV) surface antigen (WHsAg) by a mean of 2.

Activation of the Liver X Receptor Pathway Inhibits HBV Replication in Primary Human Hepatocytes.

Background And Aims: Hepatitis B virus (HBV) infection is ranked among the top health priorities worldwide. Accumulating evidence suggests that HBV infection and replication are closely associated with liver metabolism. The liver X receptors (LXRs), which belong to the superfamily of nuclear hormone receptors, are important physiological regulators of lipid and cholesterol metabolism.

Machine-learning based patient classification using Hepatitis B virus full-length genome quasispecies from Asian and European cohorts.

Chronic infection with Hepatitis B virus (HBV) is a major risk factor for the development of advanced liver disease including fibrosis, cirrhosis, and hepatocellular carcinoma (HCC). The relative contribution of virological factors to disease progression has not been fully defined and tools aiding the deconvolution of complex patient virus profiles is an unmet clinical need. Variable viral mutant signatures develop within individual patients due to the low-fidelity replication of the viral polymerase creating 'quasispecies' populations.

Direct Inhibition of Hepatitis B e Antigen by Core Protein Allosteric Modulator.

Hepatitis B e antigen (HBeAg) is an important immunomodulator for promoting host immune tolerance during chronic hepatitis B (CHB) infection. In patients with CHB, HBeAg loss and seroconversion represent partial immune control of CHB infection and are regarded as valuable endpoints. However, the current approved treatments have only a limited efficacy in achieving HBeAg seroconversion in HBeAg-positive patients.

PAPD5/7 Are Host Factors That Are Required for Hepatitis B Virus RNA Stabilization.

RG7834 is a potent, orally bioavailable small-molecule inhibitor of hepatitis B virus (HBV) gene expression that belongs to the dihydroquinolizinone (DHQ) chemical class and uniquely blocks production of both viral DNA and antigens. In this study, we used DHQ compounds as tools in a compound-based adaptation version of the yeast three-hybrid screen to identify the cognate cellular protein targets, the non-canonical poly(A) RNA polymerase associated domain containing proteins 5 and 7 (PAPD5 and PAPD7). Interaction with RG7834 was mapped to the catalytic domains of the two cellular enzymes.

Liver-Targeted Anti-HBV Single-Stranded Oligonucleotides with Locked Nucleic Acid Potently Reduce HBV Gene Expression In Vivo.

Chronic hepatitis B infection (CHB) is an area of high unmet medical need. Current standard-of-care therapies only rarely lead to a functional cure, defined as durable hepatitis B surface antigen (HBsAg) loss following treatment. The goal for next generation CHB therapies is to achieve a higher rate of functional cure with finite treatment duration.

Discovery of Small Molecule Therapeutics for Treatment of Chronic HBV Infection.

The chronic infection of hepatitis B virus (HBV) inflicts 250 million people worldwide representing a major public health threat. A significant subpopulation of patients eventually develop cirrhosis and hepatocellular carcinoma (HCC). Unfortunately, none of the current standard therapies for chronic hepatitis B (CHB) result in a satisfactory clinical cure rate.

A novel orally available small molecule that inhibits hepatitis B virus expression.

Background & Aims: The hallmarks of chronic HBV infection are a high viral load (HBV DNA) and even higher levels (>100-fold in excess of virions) of non-infectious membranous particles containing the tolerogenic viral S antigen (HBsAg). Currently, standard treatment effectively reduces viremia but only rarely results in a functional cure (defined as sustained HBsAg loss). There is an urgent need to identify novel therapies that reduce HBsAg levels and restore virus-specific immune responsiveness in patients.

Discovery of Novel Small-Molecule Inhibitors of LIM Domain Kinase for Inhibiting HIV-1.

A dynamic actin cytoskeleton is necessary for viral entry, intracellular migration, and virion release. For HIV-1 infection, during entry, the virus triggers early actin activity by hijacking chemokine coreceptor signaling, which activates a host dependency factor, cofilin, and its kinase, the LIM domain kinase (LIMK). Although knockdown of human LIM domain kinase 1 (LIMK1) with short hairpin RNA (shRNA) inhibits HIV infection, no specific small-molecule inhibitor of LIMK has been available.

Discovery and Pre-Clinical Characterization of Third-Generation 4-H Heteroaryldihydropyrimidine (HAP) Analogues as Hepatitis B Virus (HBV) Capsid Inhibitors.

Described herein are the discovery and structure-activity relationship (SAR) studies of the third-generation 4-H heteroaryldihydropyrimidines (4-H HAPs) featuring the introduction of a C6 carboxyl group as novel HBV capsid inhibitors. This new series of 4-H HAPs showed improved anti-HBV activity and better drug-like properties compared to the first- and second-generation 4-H HAPs. X-ray crystallographic study of analogue 12 (HAP_R01) with Cp149 Y132A mutant hexamer clearly elucidated the role of C6 carboxyl group played for the increased binding affinity, which formed strong hydrogen bonding interactions with capsid protein and coordinated waters.

HBVcircle: A novel tool to investigate hepatitis B virus covalently closed circular DNA.

Background & Aims: Hepatitis B virus (HBV) covalently closed circular DNA (cccDNA) persists as a stable episome in infected hepatocytes and serves as a template for the transcription of all viral genes. Due to the narrow host range of HBV, the development of a robust mouse model that supports cccDNA-dependent viral replication is a key hurdle in the development of novel HBV therapeutics. This study aimed to develop a novel tool to investigate HBV cccDNA.

Heteroaryldihydropyrimidine (HAP) and Sulfamoylbenzamide (SBA) Inhibit Hepatitis B Virus Replication by Different Molecular Mechanisms.

Heteroaryldihydropyrimidine (HAP) and sulfamoylbenzamide (SBA) are promising non-nucleos(t)ide HBV replication inhibitors. HAPs are known to promote core protein mis-assembly, but the molecular mechanism of abnormal assembly is still elusive. Likewise, the assembly status of core protein induced by SBA remains unknown.

Cytosolic sulfotransferase 1A1 regulates HIV-1 minus-strand DNA elongation in primary human monocyte-derived macrophages.

Background: The cellular sulfonation pathway modulates key steps of virus replication. This pathway comprises two main families of sulfonate-conjugating enzymes: Golgi sulfotransferases, which sulfonate proteins, glycoproteins, glycolipids and proteoglycans; and cytosolic sulfotransferases (SULTs), which sulfonate various small molecules including hormones, neurotransmitters, and xenobiotics. Sulfonation controls the functions of numerous cellular factors such as those involved in cell-cell interactions, cell signaling, and small molecule detoxification.

BIRC2/cIAP1 Is a Negative Regulator of HIV-1 Transcription and Can Be Targeted by Smac Mimetics to Promote Reversal of Viral Latency.

Combination antiretroviral therapy (ART) is able to suppress HIV-1 replication to undetectable levels. However, the persistence of latent viral reservoirs allows for a rebound of viral load upon cessation of therapy. Thus, therapeutic strategies to eradicate the viral latent reservoir are critically needed.