A fragment-based drug discovery developed on ciclopirox for inhibition of Hepatitis B virus core protein: An in silico study

Discovery of novel HBV core protein inhibitors by high throughput virtual screening

Hepatitis B Virus (HBV) constitutes a chronic viral infection with limited therapeutic options and a significant global health challenge. The virus lifecycle intricacy significantly relies on the core protein crucial for virus structure stability and interaction with host cells thus contributing to the infection's persistence and severity. This study employs advanced techniques for the identification of novel core protein inhibitors through the screening of two chemical databases ZINC and BIMP utilizing computational methods such as structure-based virtual screening, drug-likeness, ADME, toxicity, consensus molecular docking, density functional theory, and 100 ns molecular dynamics simulation. The compound ZINC00674395 possesses high affinity and specificity towards core protein demonstrating drug-like properties, favorable ADME profiles, non-toxicity, and favorable electronic configuration with high stability at the core protein active site thus highlighting its potential as a therapeutic agent. These findings offer new insights into core protein interaction and pave the way for developing effective HBV therapeutics.

Computer-aided drug repurposing & discovery for Hepatitis B capsid protein

The primary objective of this study is to harness computer-aided drug repurposing (CADR) techniques to identify existing FDA-approved drugs that can potentially disrupt the assembly of the Hepatitis B Virus (HBV) core protein (HBcAg), an essential process in the virus's life cycle. By targeting this critical step, our study aims to expand the repertoire of therapeutic options for managing chronic Hepatitis B infection, a major global health challenge. Utilizing a combination of computational methods, including the CavityPlus server for ability to analyze druggable protein cavities and extract pharmacophore features and LigandScout for pharmacophore-based virtual screening of a vast library of FDA-approved drugs was conducted. Molecular dynamic simulation (MDS) was employed to evaluate the stability of HBcAg, complexed with Heteroaryldihydropyrimidine (HAP) and statins exhibiting particularly strong binding energies and conformational compatibility. Our approach focused on identifying pharmacophore features that align with known HBcAg inhibitors. The study identified several promising candidates, including Ciclopirox olamine, Voriconazole, Enasidenib, and statins, demonstrating potential interactions with HBc protein residues. Molecular docking further validated these interactions. The significance of these findings lies in their potential to offer new, effective therapeutic strategies for HBV treatment, particularly as alternatives to current therapies that often suffer from issues of viral resistance and adverse side effects. MDS analysis verified the robustness of HAP and statins by showing a high level of binding energies and compatibility with HBcAg. Our results provide a foundation for further experimental validation and underscore the utility of computer-aided drug repurposing as a rapid, cost-effective approach to drug discovery in antiviral research. This study contributes to our understanding of HBV biology and opens avenues for developing novel anti-HBV therapies based on repurposed drugs. The highlighted compound may also enhance the challenges of drug resistance when used as a combination therapy.

Pharmacophore modeling and QSAR analysis of anti-HBV flavonols

Due to its global burden, Targeting Hepatitis B virus (HBV) infection in humans is crucial. Herbal medicine has long been significant, with flavonoids demonstrating promising results. Hence, the present study aimed to establish a way of identifying flavonoids with anti-HBV activities. Flavonoid structures with anti-HBV activities were retrieved. A flavonol-based pharmacophore model was established using LigandScout v4.4. Screening was performed using the PharmIt server. A QSAR equation was developed and validated with independent sets of compounds. The applicability domain (AD) was defined using Euclidean distance calculations for model validation. The best model, consisting of 57 features, was generated. High-throughput screening (HTS) using the flavonol-based model resulted in 509 unique hits. The model's accuracy was further validated using a set of FDA-approved chemicals, demonstrating a sensitivity of 71% and a specificity of 100%. Additionally, the QSAR model with two predictors, x4a and qed, exhibited predictive solid performance with an adjusted-R2 value of 0.85 and 0.90 of Q2. PCA showed essential patterns and relationships within the dataset, with the first two components explaining nearly 98% of the total variance. Current HBV therapies tend to fail to provide a complete cure, emphasizing the need for new therapies. This study's importance was to highlight flavonols as potential anti-HBV medicines, presenting a supplementary option for existing therapy. The QSAR model has been validated with two separate chemical sets, guaranteeing its reproducibility and usefulness for other flavonols by utilizing the predictive characteristics of X4A and qed. These results provide new possibilities for discovering future anti-HBV drugs by integrating modeling and experimental research.

Novel mechanistic insights - A brand new Era for anti-HBV drugs

Hepatitis B Virus (HBV) remains a critical global health issue, with substantial morbidity and mortality. Current therapies, including interferons and nucleoside analogs, often fail to achieve complete cure or functional eradication. This review explores recent advances in anti-HBV agents, focusing on their innovative mechanisms of action. HBV entry inhibitors target the sodium taurocholate cotransporting polypeptide (NTCP) receptor, impeding viral entry, while nucleus translocation inhibitors disrupt key viral life cycle steps, preventing replication. Capsid assembly modulators inhibit covalently closed circular DNA (cccDNA) formation, aiming to eradicate the persistent viral reservoir. Transcription inhibitors targeting cccDNA and integrated DNA offer significant potential to suppress HBV replication. Immunomodulatory agents are highlighted for their ability to enhance host immune responses, facil-itating better control and possible eradication of HBV. These novel approaches represent significant advancements in HBV therapy, providing new strategies to overcome current treatment limitations. The development of cccDNA reducers is particularly critical, as they directly target the persistent viral reservoir, offering a promising pathway towards achieving a functional cure or complete viral eradication. Continued research in this area is essential to advance the effectiveness of anti-HBV therapies.

Dental complications as a potential indicator of Redondovirus infection: a cross-sectional study

BACKGROUND

Redondoviridae is a newly discovered virus family linked to oral and respiratory conditions in people, while there is still debate about whether it is also coinfected with other respiratory viruses. This study aimed to determine the frequency of Redondovirus (ReDoV) in nasopharyngeal samples and to investigate any possible links to SARS-CoV-2 infections.

METHODS

A polymerase chain reaction (PCR) test was conducted on 731 nasopharyngeal samples from individuals referred to medical centers in Tehran, Iran, for SARS-CoV-2 testing to investigate the prevalence of ReDoV. An oral interview was performed to complete information on dental issues and the individuals' demographics, symptoms, and vaccination history.

RESULTS

The prevalence of ReDoV was 25.99%, and 15.26% had a coinfection with SARS-CoV-2. No notable correlation was found regarding ReDoVs and SARS-CoV-2 infections (p > 0.05). Women had a higher ReDoV positivity rate of 18.47% compared to men at 7.52% (p = 0.12), and there was no significant correlation between age groups and ReDoV presence. Nonetheless, a significant association was noted between ReDoVs and dental/gum issues (p < 0.0001, OR: 13.0326). A phylogenetic analysis showed that ReDoVs originated from various human-related clusters.

CONCLUSIONS

These results highlight the potential for detecting ReDoVs in nasopharyngeal samples of people with gum or dental issues. Additionally, conducting more ReDoV epidemiological research and proposing oral health as a possible marker for ReDoV infections is important.

HBCVTr: an end-to-end transformer with a deep neural network hybrid model for anti-HBV and HCV activity predictor from SMILES

Hepatitis B and C viruses (HBV and HCV) are significant causes of chronic liver diseases, with approximately 350 million infections globally. To accelerate the finding of effective treatment options, we introduce HBCVTr, a novel ligand-based drug design (LBDD) method for predicting the inhibitory activity of small molecules against HBV and HCV. HBCVTr employs a hybrid model consisting of double encoders of transformers and a deep neural network to learn the relationship between small molecules' simplified molecular-input line-entry system (SMILES) and their antiviral activity against HBV or HCV. The prediction accuracy of HBCVTr has surpassed baseline machine learning models and existing methods, with R-squared values of 0.641 and 0.721 for the HBV and HCV test sets, respectively. The trained models were successfully applied to virtual screening against 10 million compounds within 240 h, leading to the discovery of the top novel inhibitor candidates, including IJN04 for HBV and IJN12 and IJN19 for HCV. Molecular docking and dynamics simulations identified IJN04, IJN12, and IJN19 target proteins as the HBV core antigen, HCV NS5B RNA-dependent RNA polymerase, and HCV NS3/4A serine protease, respectively. Overall, HBCVTr offers a new and rapid drug discovery and development screening method targeting HBV and HCV.

An overview of anti-Hepatitis B virus flavonoids and their mechanisms of action

Flavonoids, a diverse group of polyphenolic compounds found in various plant-based foods, have garnered attention for their potential in combating Hepatitis B Virus (HBV) infection. Flavonoids have demonstrated promising anti-HBV activities by interfering with multiple stages of the HBV life cycle, making them promising candidates for novel antiviral agents. Certain plant families, such as Theaceae, Asteraceae, Lamiaceae, and Gentianaceae, are of particular interest for their flavonoid-rich members with anti-HBV activities. Evidences, both in vitro and in vivo, supports the anti-HBV potential of flavonoids. These subsets of compound exert their anti-HBV effects through various mechanisms, including inhibiting viral entry, disrupting viral replication, modulating transcription factors, enhancing the immune response, and inducing autophagy. The antioxidant properties of flavonoids play a crucial role in modulating oxidative stress associated with HBV infection. Several flavonoids like epigallocatechin gallate (EGCG), proanthocyanidin (PAC), hexamethoxyflavone, wogonin, and baicalin have shown significant anti-HBV potential, holding promise as therapeutic agents. Synergistic effects between flavonoids and existing antiviral therapies offer a promising approach to enhance antiviral efficacy and reduce drug resistance. Challenges, including limited bioavailability, translation from preclinical studies to clinical practice, and understanding precise targets, need to be addressed. Future research should focus on clinical trials, combination therapies, and the development of flavonoid derivatives with improved bioavailability, and optimizing their effectiveness in managing chronic HBV infections.