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Introduction: To examine hemispheric differences in cerebral autoregulation in children with traumatic brain injury (TBI). After IRB approval and consent, subjects underwent static cerebral autoregulation testing during the first 9 days after PICU admission. Cerebral autoregulation was quantified using the autoregulatory index (ARI).Results: Forty-two (27 M:15 F) children (10 +/- 5 years) with TBI and admission Glasgow coma scale score (5 +/- 2) were enrolled. Seven (54%) of the 13 children with focal TBI and 8 (28%) of 29 children with diffuse TBI had impairment or absence of cerebral autoregulation of at least one hemisphere. In patients with isolated focal TBI, ARI was lower (0.40 +/- 0.40 vs. 0.67 +/- 0.40; P = 0.03) in the side of TBI than in the unaffected hemisphere, but cerebral autoregulation was often impaired on the side without TBI or shift (5/13) on head CT. There was no difference in ARI between hemispheres in children with diffuse TBI, with or without superimposed focal lesions (P = 0.17). Patients with bilateral intact cerebral autoregulation tended to have higher 6 month Glasgow Outcome Score (GOS) than patients with either unilateral or bilateral cerebral autoregulation impairment (GOS 4.0 +/- 0.60 vs. 3.6 +/- 0.80; P = 0.08).Conclusions: Hemispheric differences in cerebral autoregulation were common in children with isolated focal TBI. Absence of TBI on CT was not always associated with intact cerebral autoregulation. Patients with bilaterally intact cerebral autoregulation tended to have better outcomes. [ABSTRACT FROM AUTHOR]

Since the SARS-CoV-2 outbreak, there have been ongoing efforts to identify antiviral molecules with broad coronavirus activity to combat COVID-19. SARS-CoV-2's main protease (M pro ) is responsible for processing the viral polypeptide into non-structural proteins essential for replication. Here, we present the biological characterization of AB-343, a covalent small-molecule inhibitor of SARS-CoV-2 M pro with potent activity in both cell-based (EC 50  = 0.018 μM) and enzymatic (K i  = 0.0028 μM) assays. AB-343 also demonstrated excellent inhibition of M pro of other human coronaviruses, including those from the alpha (229E and NL63) and beta (SARS-CoV, MERS, OC43, and HKU1) families, suggesting the compound could be active against future coronaviruses. No change in AB-343 potency was observed against M pro of SARS-CoV-2 variants of concern, including Omicron, suggesting that AB-343 could be developed as a treatment against currently circulating coronaviruses. AB-343 also remained active against several M pro variants which confer significant resistance to nirmatrelvir and ensitrelvir, which are presently the only M pro inhibitors authorized for the treatment of COVID-19, further supporting the evaluation of AB-343 as a novel and potent therapeutic for COVID-19 and other coronaviruses., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Employees of Arbutus Biopharma may hold company stock. Other authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Lowering hepatitis B surface antigen (HBsAg) levels from covalently closed circular DNA (cccDNA) and the integrated genome could reduce the persistence of hepatitis B virus (HBV) infection. Since HBV replication occurs in the liver and to ameliorate the peripheral neuropathy observed with a first-generation tricyclic 4-pyridone PAPD5/7 inhibitor ( AB-452 ) having high systemic exposure, we focused on increasing the hepatocyte concentration and reducing plasma levels. Optimization of a novel series of PAPD5/7 inhibitors that decrease HBsAg levels led to the tetracyclic 2-pyridone AB-161 , which was similarly potent to AB-452 in vitro and in vivo but showed dramatically higher rodent liver-to-plasma ratios. There were no neurobehavioral effects with AB-161 in dogs up to 45 mg/kg after 60 days, unlike with AB-452 , where these were observed at lower doses by day 14. AB-161 was then advanced into 90-day GLP toxicology studies, where the improved neurotoxicity profile persisted, but reproductive issues emerged, leading to discontinuation.

The recent global COVID-19 pandemic has highlighted treatments for coronavirus infection as an unmet medical need. The main protease (M pro ) has been an important target for the development of SARS-CoV-2 direct-acting antivirals. Nirmatrelvir as a covalent M pro inhibitor was the first such approved therapy. Although M pro inhibitors of various chemical classes have been reported, they are generally less active against nirmatrelvir-resistant variants and have limited pan-coronavirus potential, presenting a significant human health risk upon future outbreaks. We here present a novel approach and utilized DNA-encoded chemical library screening to identify the noncovalent M pro inhibitor 5 , which demonstrated a distinct binding mode to nirmatrelvir. A macrocyclization strategy designed to lock the active conformation resulted in lactone 12 with significantly improved antiviral activity. Further optimization led to the potent lactam 26 , which demonstrated exceptional potency against nirmatrelvir-resistant variants as well as against a panel of viral main proteases from other coronaviruses.

HBV capsid assembly modulators (CAMs) target the core protein and inhibit pregenomic RNA encapsidation and viral replication. HBV CAMs also interfere with cccDNA formation during de novo infection, which in turn suppresses transcription and production of HBV antigens. In this report, we describe the antiviral activities of AB-836, a potent and highly selective HBV CAM. AB-836 inhibited viral replication (EC 50  = 0.010 μM) in HepDE19 cells, and cccDNA formation (EC 50  = 0.18 μM) and HBsAg production (EC 50  = 0.20 μM) in HepG2-NTCP cells during de novo infection. AB-836 showed broad genotype coverage, remained active against variants resistant to nucleos(t)ide analogs, and demonstrated improved antiviral potency against core variants resistant to other CAMs. AB-836 also mediated potent inhibition of HBV replication in a hydrodynamic injection mouse model, reducing both serum and liver HBV DNA. In a Phase 1 clinical study, 28 days of once-daily AB-836 oral dosing at 50, 100, and 200 mg resulted in mean serum HBV DNA declines of 2.57, 3.04, and 3.55 log 10 IU/mL from baseline, respectively. Neither on-treatment viral rebound nor the emergence of viral resistance was observed during the 28-day treatment period. Furthermore, HBV DNA sequence analysis of baseline samples from the Phase 1 study revealed that 51.4% of the chronic hepatitis B participants contained at least one core polymorphism within the CAM-binding pocket, suggesting that genetic variations exist at this site. While AB-836 was discontinued due to clinical safety findings, data from the preclinical and clinical studies could help inform future optimization of HBV CAMs., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Employees of Arbutus Biopharma may hold company stock. EG reports serving on advisory boards for AbbVie, Aligos Therapeutics, Arbutus Biopharma, Gilead Sciences, Janssen, Roche, Vir and Virion Therapeutics., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Objective: This communication presents the results of defining a tribal health jurisdiction by a combination of tribal affiliation (TA) and case address., Materials and Methods: Through a county-tribal partnership, Geographic Information System (GIS) software and custom code were used to extract tribal data from county data by identifying reservation addresses in county extracts of COVID-19 case records from December 30, 2019, to December 31, 2022 (n = 374 653) and COVID-19 vaccination records from December 1, 2020, to April 18, 2023 (n = 2 355 058)., Results: The tool identified 1.91 times as many case records and 3.76 times as many vaccination records as filtering by TA alone., Discussion and Conclusion: This method of identifying communities by patient address, in combination with TA and enrollment, can help tribal health jurisdictions attain equitable access to public health data, when done in partnership with a data sharing agreement. This methodology has potential applications for other populations underrepresented in public health and clinical research., (© The Author(s) 2024. Published by Oxford University Press on behalf of the American Medical Informatics Association.)

Chronic hepatitis B is a global health concern with a high risk of end-stage liver disease. Current standard-of-care agents have low cure rates, and new therapies are needed. Small interfering RNAs (siRNAs) that target viral RNAs fulfill a gap not addressed by standard-of-care agents and may contribute to a functional cure. Here, we describe the preclinical characterization of imdusiran (AB-729), a novel, pan-genotypic siRNA therapeutic that effectively reduces HBsAg, viral antigens, and viral replication in chronic hepatitis B patients and is currently in Phase 2 clinical studies. In hepatitis B virus (HBV) cell-based systems, imdusiran possessed pan-genotypic nanomolar potency and retained activity against HBV target site polymorphisms. Imdusiran was active against nucleos(t)ide analogue- and capsid assembly modulator-resistant HBV isolates, and combination with standard-of-care agents was additive. In an HBV adeno-associated virus mouse model, HBsAg was reduced up to 3.7 log 10 after a single imdusiran dose, with sustained suppression for 10 weeks. Imdusiran did not intrinsically stimulate cytokine release in healthy donor human whole blood, supportive of its mechanism of action as a direct acting RNA interference antiviral. Taken together, these data support imdusiran in combination treatment approaches toward chronic hepatitis B functional cure.

Isoquinolinone-based HBV capsid assembly modulators that bind at the dimer:dimer interface of HBV core protein have been shown to suppress viral replication in chronic hepatitis B patients. Analysis of their binding mode by protein X-ray crystallography has identified a region of the small molecule where the application of a constraint can lock the preferred binding conformation and has allowed for further optimization of this class of compounds. Key analogues demonstrated single digit nM EC 50 values in reducing HBV DNA in a HepDE19 cellular assay in addition to favorable ADME and pharmacokinetic properties, leading to a high degree of oral efficacy in a relevant in vivo hydrodynamic injection mouse model of HBV infection, with 12e effecting a 3 log 10 decline in serum HBV DNA levels at a once daily dose of 1 mg/kg. Additionally, maintenance of activity was observed in clinically relevant HBV core protein variants T33N and I105T., Competing Interests: The authors declare no competing financial interest., (© 2024 American Chemical Society.)

The recent COVID-19 pandemic underscored the limitations of currently available direct-acting antiviral treatments against acute respiratory RNA-viral infections and stimulated major research initiatives targeting anticoronavirus agents. Two novel nsp5 protease (MPro) inhibitors have been approved, nirmatrelvir and ensitrelvir, along with two existing nucleos(t)ide analogues repurposed as nsp12 polymerase inhibitors, remdesivir and molnupiravir, but a need still exists for therapies with improved potency and systemic exposure with oral dosing, better metabolic stability, and reduced resistance and toxicity risks. Herein, we summarize our research toward identifying nsp12 inhibitors that led to nucleoside analogues 10e and 10n , which showed favorable pan-coronavirus activity in cell-infection screens, were metabolized to active triphosphate nucleotides in cell-incubation studies, and demonstrated target (nsp12) engagement in biochemical assays.

HBV RNA destabilizers are a class of small-molecule compounds that target the noncanonical poly(A) RNA polymerases PAPD5 and PAPD7, resulting in HBV RNA degradation and the suppression of viral proteins including the hepatitis B surface antigen (HBsAg). AB-161 is a next-generation HBV RNA destabilizer with potent antiviral activity, inhibiting HBsAg expressed from cccDNA and integrated HBV DNA in HBV cell-based models. AB-161 exhibits broad HBV genotype coverage, maintains activity against variants resistant to nucleoside analogs, and shows additive effects on HBV replication when combined with other classes of HBV inhibitors. In AAV-HBV-transduced mice, the dose-dependent reduction of HBsAg correlated with concentrations of AB-161 in the liver reaching above its effective concentration mediating 90% inhibition (EC 90 ), compared to concentrations in plasma which were substantially below its EC 90 , indicating that high liver exposure drives antiviral activities. In preclinical 13-week safety studies, minor non-adverse delays in sensory nerve conductance velocity were noted in the high-dose groups in rats and dogs. However, all nerve conduction metrics remained within physiologically normal ranges, with no neurobehavioral or histopathological findings. Despite the improved neurotoxicity profile, microscopic findings associated with male reproductive toxicity were detected in dogs, which subsequently led to the discontinuation of AB-161's clinical development.

The protein that forms the inner shell of the HBV virus, known as the capsid core protein, plays a crucial role in allowing chronic HBV infections to persist. Studies have shown that disrupting the assembly of the capsid can effectively combat the virus, and small molecule drugs that target the HBV capsid assembly modulator (CAM) process have been successful in clinical trials. Herein is described a distinct series of di-fluoro azepane CAMs with exceptional potency, pharmacokinetic, and solubility properties., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Hepatitis B virus (HBV) replicates its genomic DNA by reverse transcription of an RNA intermediate, termed pregenomic RNA (pgRNA), within nucleocapsid. It had been shown that transfection of in vitro -transcribed pgRNA initiated viral replication in human hepatoma cells. We demonstrated here that viral capsids, single-stranded DNA, relaxed circular DNA (rcDNA) and covalently closed circular DNA (cccDNA) became detectable sequentially at 3, 6, 12, and 24 h post-pgRNA transfection into Huh7.5 cells. The levels of viral DNA replication intermediates and cccDNA peaked at 24 and 48 h post-pgRNA transfection, respectively. HBV surface antigen (HBsAg) became detectable in culture medium at day 4 posttransfection. Interestingly, the early robust viral DNA replication and cccDNA synthesis did not depend on the expression of HBV X protein (HBx), whereas HBsAg production was strictly dependent on viral DNA replication and expression of HBx, consistent with the essential role of HBx in the transcriptional activation of cccDNA minichromosomes. While the robust and synchronized HBV replication within 48 h post-pgRNA transfection is particularly suitable for the precise mapping of the HBV replication steps, from capsid assembly to cccDNA formation, targeted by distinct antiviral agents, the treatment of cells starting at 48 h post-pgRNA transfection allows the assessment of antiviral agents on mature nucleocapsid uncoating, cccDNA synthesis, and transcription, as well as viral RNA stability. Moreover, the pgRNA launch system could be used to readily assess the impacts of drug-resistant variants on cccDNA formation and other replication steps in the viral life cycle. IMPORTANCE Hepadnaviral pgRNA not only serves as a template for reverse transcriptional replication of viral DNA but also expresses core protein and DNA polymerase to support viral genome replication and cccDNA synthesis. Not surprisingly, cytoplasmic expression of duck hepatitis B virus pgRNA initiated viral replication leading to infectious virion secretion. However, HBV replication and antiviral mechanism were studied primarily in human hepatoma cells transiently or stably transfected with plasmid-based HBV replicons. The presence of large amounts of transfected HBV DNA or transgenes in cellular chromosomes hampered the robust analyses of HBV replication and cccDNA function. As demonstrated here, the pgRNA launch HBV replication system permits the accurate mapping of antiviral target and investigation of cccDNA biosynthesis and transcription using secreted HBsAg as a convenient quantitative marker. The effect of drug-resistant variants on viral capsid assembly, genome replication, and cccDNA biosynthesis and function can also be assessed using this system.

The HBV capsid core protein serves a number of important functions in the viral life cycle enabling chronic HBV infection to persist, and therefore is a promising drug target. Interfering with capsid assembly has shown efficacy in clinical trials with small molecule capsid assembly modulators (CAMs). Herein is described the further optimization of a progressive series of diazepinone HBV CAMs., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

The HBV core protein serves multiple essential functions in the viral life cycle that enable chronic HBV infection to persist, and as such, represents a promising drug target. Modulation of the HBV capsid assembly has shown efficacy in early clinical trials through use of small molecule capsid assembly modulators (CAMs). Herein is described the evolution and SAR of a novel pyrazolo piperidine lead series into advanced oxadiazepinone HBV CAMs., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Noncanonical poly(A) polymerases PAPD5 and PAPD7 (PAPD5/7) stabilize hepatitis B virus (HBV) RNA via the interaction with the viral posttranscriptional regulatory element (PRE), representing new antiviral targets to control HBV RNA metabolism, hepatitis B surface antigen (HBsAg) production, and viral replication. Inhibitors targeting these proteins are being developed as antiviral therapies; therefore, it is important to understand how PAPD5/7 coordinate to stabilize HBV RNA. Here, we utilized a potent small-molecule AB-452 as a chemical probe, along with genetic analyses to dissect the individual roles of PAPD5/7 in HBV RNA stability. AB-452 inhibits PAPD5/7 enzymatic activities and reduces HBsAg both in vitro (50% effective concentration [EC 50 ] ranged from 1.4 to 6.8 nM) and in vivo by 0.94 log 10 . Our genetic studies demonstrate that the stem-loop alpha sequence within PRE is essential for both maintaining HBV poly(A) tail integrity and determining sensitivity toward the inhibitory effect of AB-452. Although neither single knockout (KO) of PAPD5 nor PAPD7 reduces HBsAg RNA and protein production, PAPD5 KO does impair poly(A) tail integrity and confers partial resistance to AB-452. In contrast, PAPD7 KO did not result in any measurable changes within the HBV poly(A) tails, but cells with both PAPD5 and PAPD7 KO show reduced HBsAg production and conferred complete resistance to AB-452 treatment. Our results indicate that PAPD5 plays a dominant role in stabilizing viral RNA by protecting the integrity of its poly(A) tail, while PAPD7 serves as a second line of protection. These findings inform PAPD5-targeted therapeutic strategies and open avenues for further investigating PAPD5/7 in HBV replication. IMPORTANCE Chronic hepatitis B affects more than 250 million patients and is a major public health concern worldwide. HBsAg plays a central role in maintaining HBV persistence, and as such, therapies that aim at reducing HBsAg through destabilizing or degrading HBV RNA have been extensively investigated. Besides directly degrading HBV transcripts through antisense oligonucleotides or RNA silencing technologies, small-molecule compounds targeting host factors such as the noncanonical poly(A) polymerase PAPD5 and PAPD7 have been reported to interfere with HBV RNA metabolism. Herein, our antiviral and genetic studies using relevant HBV infection and replication models further characterize the interplays between the cis element within the viral sequence and the trans elements from the host factors. PAPD5/7-targeting inhibitors, with oral bioavailability, thus represent an opportunity to reduce HBsAg through destabilizing HBV RNA.

The HBV core protein is a druggable target of interest due to the multiple essential functions in the HBV life cycle to enable chronic HBV infection. The core protein oligomerizes to form the viral capsid, and modulation of the HBV capsid assembly has shown efficacy in clinical trials. Herein is described the identification and hit to lead SAR of a novel series of pyrazolo piperidine HBV capsid assembly modulators., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Herein is reported a novel screening paradigm PURE ( P 450s u nder re striction) for the identification and optimization of hits as part of a hepatitis B virus (HBV) antiviral discovery program. To closely represent in vivo hepatocytes, differentiated HepaRG cells (dHRGs) and primary human hepatocytes (PHHs) were used as the basis for an HBV infection system. However, a significant challenge arose during potency evaluation in using cultured dHRGs and PHHs as screening platforms because, as with hepatocytes in vivo , these cells express active cytochrome P450 enzymes and thus can metabolize test compounds. The observed antiviral effects may be the cumulative result of a dynamic pool of parent compound and metabolites thus confounding structure activity relationship (SAR) interpretation and subsequent optimization design initiatives. We show here that PURE methodology restricts metabolism of HBV-infected dHRGs and PHHs and thus provides highly informative potency data for decision-making on key representative antiviral compounds., Competing Interests: The authors declare no competing financial interest.

The HBV core protein has multiple essential functions in the HBV life cycle to enable chronic HBV infection. The core protein oligomerizes to form the viral capsid, and modulation of the HBV capsid assembly process has shown clinical efficacy in early clinical trials. Herein is described the SAR exploration of NVR 3-778, the first clinical compound in the sulfonyl carboxamide class., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

In the case presented, a patient has an unexplained episode of hypertension during aneurysm clipping. Following the procedure, the patient was discovered to have bilateral thalamic infarctions unrelated to the vascular location of the aneurysm. After a review of the case, it becomes apparent that intracranial hypotension caused by lumbar over drainage of cerebrospinal fluid (CSF) is the likely cause of both the episode of intraoperative hypertension and the thalamic infarcts. It is often presumed that having an open dura protects against intracranial hypotension and subsequent herniation. We present this case to suggest that opening the dura might not be protective in all cases and anesthesiologists must pay particular attention to the rate of CSF drainage. Lumbar CSF drainage is a technique frequently employed during neurological surgery and it is important for anesthesiologists to understand the signs, symptoms, and potential consequences of intracranial hypotension from rapid drainage.

NVR 3-778 is the first capsid assembly modulator (CAM) that has demonstrated antiviral activity in hepatitis B virus (HBV)-infected patients. NVR 3-778 inhibited the generation of infectious HBV DNA-containing virus particles with a mean antiviral 50% effective concentration (EC 50 ) of 0.40 µM in HepG2.2.15 cells. The antiviral profile of NVR 3-778 indicates pan-genotypic antiviral activity and a lack of cross-resistance with nucleos(t)ide inhibitors of HBV replication. The combination of NVR 3-778 with nucleos(t)ide analogs in vitro resulted in additive or synergistic antiviral activity. Mutations within the hydrophobic pocket at the dimer-dimer interface of the core protein could confer resistance to NVR 3-778, which is consistent with the ability of the compound to bind to core and to induce capsid assembly. By targeting core, NVR 3-778 inhibits pregenomic RNA encapsidation, viral replication, and the production of HBV DNA- and HBV RNA-containing particles. NVR 3-778 also inhibited de novo infection and viral replication in primary human hepatocytes with EC 50 values of 0.81 µM against HBV DNA and between 3.7 and 4.8 µM against the production of HBV antigens and intracellular HBV RNA. NVR 3-778 showed favorable pharmacokinetics and safety in animal species, allowing serum levels in excess of 100 µM to be achieved in mice and, thus, enabling efficacy studies in vivo The overall preclinical profile of NVR 3-778 predicts antiviral activity in vivo and supports its further evaluation for safety, pharmacokinetics, and antiviral activity in HBV-infected patients., (Copyright © 2018 Lam et al.)

Background & Aims: NVR3-778 is a capsid assembly modulator in clinical development. We determined the in vivo antiviral efficacy and effects on innate and endoplasmic reticulum (ER) stress responses of NVR3-778 alone or in combination with pegylated interferon alpha (peg-IFN) and compared with entecavir., Methods: We performed 2 studies, with a total of 61 uPA/SCID mice with humanized livers. Mice were infected with a hepatitis B virus (HBV) genotype C preparation; we waited 8 weeks for persistent infection of the human hepatocytes in livers of mice. Mice were then randomly assigned to groups (5 or 6 per group) given vehicle (control), NVR3-778, entecavir, peg-IFN, NVR3-778 + entecavir, or NVR3-778 + peg-IFN for 6 weeks. We measured levels of HB surface antigen, HB e antigen, HBV RNA, alanine aminotransferase, and human serum albumin at different time points. Livers were collected and analyzed by immunohistochemistry; levels of HBV DNA, covalently closed circular DNA, and HBV RNA, along with markers of ER stress and IFN response, were quantified., Results: Mice given NVR3-778 or entecavir alone for 6 weeks had reduced serum levels of HBV DNA compared with controls or mice given peg-IFN. The largest reduction was observed in mice given NVR3-778 + peg-IFN; in all mice in this group, the serum level of HBV DNA was below the limit of quantification. NVR3-778 and peg-IFN, but not entecavir, also reduced serum level of HBV RNA. The largest effect was obtained in the NVR3-778 + peg-IFN group, in which serum level of HBV RNA was below the limit of quantification. Levels of HB surface antigen and HB e antigen were reduced significantly in only the groups that received peg-IFN. Levels of covalently closed circular DNA did not differ significantly among groups. NVR3-778 was not associated with any significant changes in level of alanine aminotransferase, the ER stress response, or IFN-stimulated genes., Conclusions: NVR3-778 has high antiviral activity in mice with humanized livers and stable HBV infection, reducing levels of serum HBV DNA and HBV RNA. Entecavir reduced levels of serum HBV DNA, but had no effect on HBV RNA. The combination of NVR3-778 and peg-IFN prevented viral replication and HBV RNA particle production to a greater extent than each compound alone or entecavir., (Copyright © 2018 AGA Institute. Published by Elsevier Inc. All rights reserved.)

The hepatitis B virus (HBV) core protein serves multiple essential functions in the viral life cycle, and antiviral agents that target the core protein are being developed. Capsid assembly modulators (CAMs) are compounds that target core and misdirect capsid assembly, resulting in the suppression of HBV replication and virion production. Besides HBV DNA, circulating HBV RNA has been detected in patient serum and can be associated with the treatment response. Here we studied the effect of HBV CAMs on the production of extracellular HBV RNA using infected HepaRG cells and primary human hepatocytes. Representative compounds from the sulfonamide carboxamide and heteroaryldihydropyrimidine series of CAMs were evaluated and compared to nucleos(t)ide analogs as inhibitors of the viral polymerase. The results showed that CAMs blocked extracellular HBV RNA with efficiencies similar to those with which they blocked pregenomic RNA (pgRNA) encapsidation, HBV DNA replication, and Dane particle production. Nucleos(t)ide analogs inhibited viral replication and virion production but not encapsidation or production of extracellular HBV RNA. Profiling of HBV RNA from both culture supernatants and patient serum showed that extracellular viral RNA consisted of pgRNA and spliced pgRNA variants with an internal deletion(s) but still retained the sequences at both the 5' and 3' ends. Similar variants were detected in the supernatants of infected cells with and without nucleos(t)ide analog treatment. Overall, our data demonstrate that HBV CAMs represent direct antiviral agents with a profile differentiated from that of nucleos(t)ide analogs, including the inhibition of extracellular pgRNA and spliced pgRNA., (Copyright © 2017 Lam et al.)

Background & Aims: Peptic ulcer disease and gastric cancer are caused most often by Helicobacter pylori strains that harbor the cag pathogenicity island, which encodes a type IV secretion system (T4SS) that injects the CagA oncoprotein into host cells. cagY is an essential gene in the T4SS and has an unusual DNA repeat structure that predicts in-frame insertions and deletions. These cagY recombination events typically lead to a reduction in T4SS function in mouse and primate models. We examined the role of the immune response in cagY-dependent modulation of T4SS function., Methods: H pylori T4SS function was assessed by measuring CagA translocation and the capacity to induce interleukin (IL)8 in gastric epithelial cells. cagY recombination was determined by changes in polymerase chain reaction restriction fragment-length polymorphisms. T4SS function and cagY in H pylori from C57BL/6 mice were compared with strains recovered from Rag1-/- mice, T- and B-cell-deficient mice, mice with deletion of the interferon gamma receptor (IFNGR) or IL10, and Rag1-/- mice that received adoptive transfer of control or Ifng-/- CD4+ T cells. To assess relevance to human beings, T4SS function and cagY recombination were assessed in strains obtained sequentially from a patient after 7.4 years of infection., Results: H pylori infection of T-cell-deficient and Ifngr1-/- mice, and transfer of CD4+ T cells to Rag1-/- mice, showed that cagY-mediated loss of T4SS function requires a T-helper 1-mediated immune response. Loss of T4SS function and cagY recombination were more pronounced in Il10-/- mice, and in control mice infected with H pylori that expressed a more inflammatory form of cagY. Complementation analysis of H pylori strains isolated from a patient over time showed changes in T4SS function that were dependent on recombination in cagY., Conclusions: Analysis of H pylori strains from mice and from a chronically infected patient showed that CagY functions as an immune-sensitive regulator of T4SS function. We propose that this is a bacterial adaptation to maximize persistent infection and transmission to a new host under conditions of a robust inflammatory response., (Copyright © 2016 AGA Institute. Published by Elsevier Inc. All rights reserved.)

The hepatitis B virus (HBV) core protein is essential for HBV replication and an important target for antiviral drug discovery. We report the first, to our knowledge, high-resolution crystal structure of an antiviral compound bound to the HBV core protein. The compound NVR-010-001-E2 can induce assembly of the HBV core wild-type and Y132A mutant proteins and thermostabilize the proteins with a Tm increase of more than 10 °C. NVR-010-001-E2 binds at the dimer-dimer interface of the core proteins, forms a new interaction surface promoting protein-protein interaction, induces protein assembly, and increases stability. The impact of naturally occurring core protein mutations on antiviral activity correlates with NVR-010-001-E2 binding interactions determined by crystallography. The crystal structure provides understanding of a drug efficacy mechanism related to the induction and stabilization of protein-protein interactions and enables structure-guided design to improve antiviral potency and drug-like properties.