Minor structural modifications of acyclic nucleoside phosphonates can dramatically affect their antiviral properties. This work discloses a shift in the selectivity spectrum of ...3-hydroxy-2-(phosphonomethoxy)propyl (HPMP) nucleotides from herpesviruses toward hepatitis B virus (HBV) induced by their acyclic chain 2-substitution with a nonpolar group. Two series of racemic (R,S)-2-methyl-3-hydroxy-2-(phosphonomethoxy)propyl (MHPMP) and (R,S)-2-ethynyl-3-hydroxy-2-(phosphonomethoxy)propyl (EHPMP) nucleotides were initially synthesized. Among these, guanine-containing derivatives exhibited significant anti-HBV activities in the submicromolar range. Enantioenriched MHPMPG and EHPMPG analogues were subsequently obtained by Sharpless asymmetric epoxidation. The (S)-enantiomers possessed an 8- to 26-fold higher potency than the relative (R)-forms. A further comparison of the EC90 values indicated that (S)-EHPMPG inhibited HBV replication more effectively than its 2-methyl analogue. A phosphonodiamidate prodrug of (S)-EHPMPG was thus prepared and found to exert a remarkably high anti-HBV activity (EC50 = 9.27 nM) with excellent selectivity (SI50 > 10,787), proving to be a promising candidate for anti-HBV drug development.
Poor glycemic control and dyslipidemia are hallmarks of type 2 diabetes mellitus (T2DM), which predispose to cardiovascular diseases. Peroxisome proliferator-activated receptor-α (
) has been ...associated with atherosclerosis, but its role in T2DM is less clear. Previously, we studied PPARα expression levels in diabetics with and without dyslipidemia (DD). In this study we described the association with fasting blood glucose, HbA1c levels and lipid levels of the study population. Patient demography and biochemical data were collected from hospitals in Islamabad, Pakistan, and RT-PCR data of
expression were retrieved from our previous study from the same cohort. We performed t-tests and regression analysis to evaluate the relationships between PPARα expression and demographic and clinical variables. As expected, body mass index and HbA1c were elevated in T2DM and DD patients compared to controls. Blood lipids (total cholesterol, triglycerides, LDL and HDL) were significantly higher in the DD group compared to the other two groups. In the T2DM and DD groups, the
expression was not associated with any of the physical and biochemical parameters measured in this study. Expression of the
gene was independent of blood lipids and glycemic control in this study. Further research is necessary to better understand the biological parameters of
expression.
•Norovirus (NV) illness in transplant recipients can be life-threatening, requiring intensive supportive care.•Clinical and laboratory features of NV illness in immunocompromised patients are ...reviewed.•Potential design and features of clinical trials in immunocompromised patients are described.•How effective trials in these patients might be used in the setting of acute outbreaks is discussed.•The current status of anti-NV drug discovery is reviewed.
Noroviruses (NV) are the most common cause of acute gastrointestinal illness in the United States and worldwide. The development of specific antiviral countermeasures has lagged behind that of other viral pathogens, primarily because norovirus disease has been perceived as brief and self-limiting and robust assays suitable for drug discovery have been lacking. The increasing recognition that NV illness can be life-threatening, especially in immunocompromised patients who often require prolonged hospitalization and intensive supportive care, has stimulated new research to develop an effective antiviral therapy. Here, we propose a path forward for evaluating drug therapy in norovirus-infected immunocompromised individuals, a population at high risk for serious and prolonged illness. The clinical and laboratory features of norovirus illness in immunocompromised patients are reviewed, and potential markers of drug efficacy are defined. We discuss the potential design of clinical trials in these patients and how an antiviral therapy that proves effective in immunocompromised patients might also be used in the setting of acute outbreaks, especially in confined settings such as nursing homes, to block the spread of infection and reduce the severity of illness. We conclude by reviewing the current status of approved and experimental compounds that might be evaluated in a hospital setting.
Abstract The VPg protein of human Norovirus (hNoV) is a multi-functional protein essential for virus replication. The un-cleaved viral precursor protein, ProPol (NS5-6) was 100-fold more efficient in ...catalyzing VPg nucleotidylylation than the mature polymerase (Pol, NS6), suggesting a specific intracellular role for ProPol. Sequential and single-point alanine substitutions revealed that several positively charged amino acids in the N-terminal region of VPg regulate its nucleotidylylation by ProPol. We provide evidence that VPg directly binds NTPs, inhibition of binding inhibits nucleotidylylation, and NTP binding appears to involve the first 13 amino acids of the protein. Substitution of multiple positively charged amino acids within the first 12 amino acids of the N-terminal region inhibits nucleotidylylation without affecting binding. Substitution of only Lys20 abolishes nucleotidylylation, but not NTP binding. These studies indicate that positively charged amino acids in the first 20 amino acids of hNoV VPg regulate its nucleotidylylation though several potential mechanisms.
Nitazoxanide (NTZ), a thiazolide anti-infective, is active against anaerobic bacteria, protozoa, and a range of viruses in cell culture models, and is currently in phase II clinical development for ...treating chronic hepatitis C. In this report, we characterize the activities of NTZ and its active metabolite, tizoxanide (TIZ), along with other thiazolides against hepatitis B virus (HBV) and hepatitis C virus (HCV) replication in standard antiviral assays. NTZ and TIZ exhibited potent inhibition of both HBV and HCV replication. NTZ was equally effective at inhibiting replication of lamivudine (LMV) and adefovir dipovoxil (ADV)-resistant HBV mutants and against 2′-C-methyl cytidine (2′CmeC) and telaprevir (VX-950)-resistant HCV mutants. NTZ displayed synergistic interactions with LMV or ADV against HBV, and with recombinant interferon alpha-2b (IFN) or 2′CmeC against HCV. Pre-treatment of HCV replicon-containing cells with NTZ potentiated the effect of subsequent treatment with NTZ plus IFN, but not NTZ plus 2′CmeC. NTZ induced reductions in several HBV proteins (HBsAg, HBeAg, HBcAg) produced by 2.2.15 cells, but did not affect HBV RNA transcription. NTZ, TIZ, and other thiazolides are promising new antiviral agents that may enhance current or future anti-hepatitis therapies.
SB 9200 is a novel, first‐in‐class oral modulator of innate immunity that is believed to act via the activation of the RIG‐I and NOD2 pathways. SB 9200 has broad‐spectrum antiviral activity against ...RNA viruses including hepatitis C virus (HCV), norovirus, respiratory syncytial virus, and influenza and has demonstrated activity against hepatitis B virus (HBV) in vitro and in vivo. In phase I clinical trials in chronically infected HCV patients, SB 9200 has been shown to reduce HCV RNA by up to 1.9 log10. Here, we demonstrate the antiviral activity of SB 9200 against a HCV replicon system and patient derived virus. Using the HCV capture‐fusion assay, we show that SB 9200 is active against diverse HCV genotypes and is also effective against HCV derived from patients who relapse following direct‐acting antiviral treatment, including viruses containing known NS5A resistance‐associated sequences. These data confirm the broad antiviral activity of SB 9200 and indicate that it may have clinical utility in HCV patients who have failed to respond to current antiviral regimens.
Metabolic-dysfunction-associated steatotic liver disease (MASLD) is becoming the most common chronic liver disease worldwide and is of concern among African Americans (AA) in the United States. This ...pilot study evaluated the differential gene expressions and identified the signature genes in the disease pathways of AA individuals with MASLD. Blood samples were obtained from MASLD patients (
= 23) and non-MASLD controls (
= 24) along with their sociodemographic and medical details. Whole-blood transcriptomic analysis was carried out using Affymetrix Clarion-S Assay. A validation study was performed utilizing TaqMan Arrays coupled with Ingenuity Pathway Analysis (IPA) to identify the major disease pathways. Out of 21,448 genes in total, 535 genes (2.5%) were significantly (
< 0.05) and differentially expressed when we compared the cases and controls. A significant overlap in the predominant differentially expressed genes and pathways identified in previous studies using hepatic tissue was observed. Of note,
and
genes were upregulated, and
was downregulated significantly.
is the top canonical pathway, and its corresponding biofunction contributes to the development of
. The findings address the knowledge gaps regarding how signature genes and functional pathways can be detected in blood samples ('liquid biopsy') in AA MASLD patients, demonstrating the potential of the blood samples as an alternative non-invasive source of material for future studies.
Abstract The human norovirus (NoV) polyprotein is cleaved into mature non-structural proteins by both mature NoV protease (Pro, NS6) and its un-cleaved precursor (ProPol, NS6-7). Processing order is ...well-established with ‘early’ and ‘late’ cleavages, but the governing enzymatic mechanisms are unknown. Enzyme kinetics of a GII Pro and ProPol were analyzed using synthetic peptides representing the five natural polyprotein cleavage sites. The relative efficiency of cleavage of the individual peptides was consistent with established polyprotein processing order, and primarily correlated with enzyme turnover ( k cat ). Enzymatic efficiencies ( k cat / K m ) of ProPol at all five sites were equivalent to, or greater than, that of Pro. Binding affinities ( K m ) for the two least efficiently cleaved sites (p20/VPg, VPg/Pro) were 2–4-fold higher than the other sites. This work further defines the role of ProPol in NoV polyprotein cleavage, and demonstrates that human norovirus polyprotein processing order is primarily an inherent property of enzymatic activity.
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