Computational Analysis Reveals Monomethylated Triazolopyrimidine as a Novel Inhibitor of SARS-CoV-2 RNA-Dependent RNA Polymerase (RdRp).

The human population is still facing appalling conditions due to several outbreaks of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) virus. The absence of specific drugs, appropriate vaccines for mutants, and knowledge of potential therapeutic agents makes this situation more difficult. Several 1, 2, 4-triazolo [1, 5-a] pyrimidine (TP)-derivative compounds were comprehensively studied for antiviral activities against RNA polymerase of HIV, HCV, and influenza viruses, and showed immense pharmacological interest. Therefore, TP-derivative compounds can be repurposed against the RNA-dependent RNA polymerase (RdRp) protein of SARS-CoV-2. In this study, a meta-analysis was performed to ensure the genomic variability and stability of the SARS-CoV-2 RdRp protein. The molecular docking of natural and synthetic TP compounds to RdRp and molecular dynamic (MD) simulations were performed to analyse the dynamic behaviour of TP compounds at the active site of the RdRp protein. TP compounds were also docked against other non-structural proteins (NSP1, NSP2, NSP3, NSP5, NSP8, NSP13, and NSP15) of SARS-CoV-2. Furthermore, the inhibition potential of TP compounds was compared with Remdesivir and Favipiravir drugs as a positive control. Additionally, TP compounds were analysed for inhibitory activity against SARS-CoV RdRp protein. This study demonstrates that TP analogues (monomethylated triazolopyrimidine and essramycin) represent potential lead molecules for designing an effective inhibitor to control viral replication. Furthermore, in vitro and in vivo studies will strengthen the use of these inhibitors as suitable drug candidates against SARS-CoV-2.

The ingenol-based protein kinase C agonist GSK445A is a potent inducer of HIV and SIV RNA transcription.

Activation of the NF-κB signaling pathway by Protein Kinase C (PKC) agonists is a potent mechanism for human immunodeficiency virus (HIV) latency disruption in vitro. However, significant toxicity risks and the lack of evidence supporting their activity in vivo have limited further evaluation of PKC agonists as HIV latency-reversing agents (LRA) in cure strategies. Here we evaluated whether GSK445A, a stabilized ingenol-B derivative, can induce HIV/simian immunodeficiency virus (SIV) transcription and virus production in vitro and demonstrate pharmacological activity in nonhuman primates (NHP). CD4+ T cells from people living with HIV and from SIV+ rhesus macaques (RM) on antiretroviral therapy (ART) exposed in vitro to 25 nM of GSK445A produced cell-associated viral transcripts as well as viral particles at levels similar to those induced by PMA/Ionomycin, indicating that GSK445A can potently reverse HIV/SIV latency. Importantly, these concentrations of GSK445A did not impair the proliferation or survival of HIV-specific CD8+ T cells, but instead, increased their numbers and enhanced IFN-γ production in response to HIV peptides. In vivo, GSK445A tolerability was established in SIV-naïve RM at 15 µg/kg although tolerability was reduced in SIV-infected RM on ART. Increases in plasma viremia following GSK445A administration were suggestive of increased SIV transcription in vivo. Collectively, these results indicate that GSK445A is a potent HIV/SIV LRA in vitro and has a tolerable safety profile amenable for further evaluation in vivo in NHP models of HIV cure/remission.

Expanding the known structure space for RNA binding: a test of 2,5-diketopiperazine.

As the importance of RNA as a therapeutic target has become increasingly recognized, the need for new chemotypes able to bind RNA has grown in significance. We hypothesized that diketopiperazines (DKPs), common substructures in natural products and protein-targeting therapeutic agents, could serve as effective scaffolds for targeting RNA. To confirm this hypothesis, we designed and synthesized two analogs, one incorporating a DKP and one not, of compounds previously demonstrated to bind an RNA critical to the life cycle of HIV-1 with high affinity and specificity. Prior to compound synthesis, calculations employing density functional methods and molecular mechanics conformational searches were used to confirm that the DKP could present functionality in a similar (albeit not identical) orientation to the non DKP-containing compound. We found that both the DKP-containing and parent compound had similar affinities to the target RNA as measured by surface plasmon resonance (SPR). Both compounds were found to have modest but equal anti-HIV activity. These results establish the feasibility of using DKPs to target RNA.

S-adenosylmethionine-dependent methyltransferase inhibitor DZNep blocks transcription and translation of SARS-CoV-2 genome with a low tendency to select for drug-resistant viral variants.

We report the in vitro antiviral activity of DZNep (3-Deazaneplanocin A; an inhibitor of S-adenosylmethionine-dependent methyltransferase) against SARS-CoV-2, besides demonstrating its protective efficacy against lethal infection of infectious bronchitis virus (IBV, a member of the Coronaviridae family). DZNep treatment resulted in reduced synthesis of SARS-CoV-2 RNA and proteins without affecting other steps of viral life cycle. We demonstrated that deposition of N6-methyl adenosine (m6A) in SARS-CoV-2 RNA in the infected cells recruits heterogeneous nuclear ribonucleoprotein A1 (hnRNPA1), an RNA binding protein which serves as a m6A reader. DZNep inhibited the recruitment of hnRNPA1 at m6A-modified SARS-CoV-2 RNA which eventually suppressed the synthesis of the viral genome. In addition, m6A-marked RNA and hnRNPA1 interaction was also shown to regulate early translation to replication switch of SARS-CoV-2 genome. Furthermore, abrogation of methylation by DZNep also resulted in defective synthesis of the 5' cap of viral RNA, thereby resulting in its failure to interact with eIF4E (a cap-binding protein), eventually leading to a decreased synthesis of viral proteins. Most importantly, DZNep-resistant mutants could not be observed upon long-term sequential passage of SARS-CoV-2 in cell culture. In summary, we report the novel role of methylation in the life cycle of SARS-CoV-2 and propose that targeting the methylome using DZNep could be of significant therapeutic value against SARS-CoV-2 infection.

Enhancing the Antiviral Potency of Nucleobases for Potential Broad-Spectrum Antiviral Therapies.

Broad-spectrum antiviral therapies hold promise as a first-line defense against emerging viruses by blunting illness severity and spread until vaccines and virus-specific antivirals are developed. The nucleobase favipiravir, often discussed as a broad-spectrum inhibitor, was not effective in recent clinical trials involving patients infected with Ebola virus or SARS-CoV-2. A drawback of favipiravir use is its rapid clearance before conversion to its active nucleoside-5'-triphosphate form. In this work, we report a synergistic reduction of flavivirus (dengue, Zika), orthomyxovirus (influenza A), and coronavirus (HCoV-OC43 and SARS-CoV-2) replication when the nucleobases favipiravir or T-1105 were combined with the antimetabolite 6-methylmercaptopurine riboside (6MMPr). The 6MMPr/T-1105 combination increased the C-U and G-A mutation frequency compared to treatment with T-1105 or 6MMPr alone. A further analysis revealed that the 6MMPr/T-1105 co-treatment reduced cellular purine nucleotide triphosphate synthesis and increased conversion of the antiviral nucleobase to its nucleoside-5'-monophosphate, -diphosphate, and -triphosphate forms. The 6MMPr co-treatment specifically increased production of the active antiviral form of the nucleobases (but not corresponding nucleosides) while also reducing levels of competing cellular NTPs to produce the synergistic effect. This in-depth work establishes a foundation for development of small molecules as possible co-treatments with nucleobases like favipiravir in response to emerging RNA virus infections.

Establishment of a Rapid Detection System for ISG20-Dependent SARS-CoV-2 Subreplicon RNA Degradation Induced by Interferon-α.

Inhaled nebulized interferon (IFN)-α and IFN-ß have been shown to be effective in the management of coronavirus disease 2019 (COVID-19). We aimed to construct a virus-free rapid detection system for high-throughput screening of IFN-like compounds that induce viral RNA degradation and suppress the replication of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We prepared a SARS-CoV-2 subreplicon RNA expression vector which contained the SARS-CoV-2 5'-UTR, the partial sequence of ORF1a, luciferase, nucleocapsid, ORF10, and 3'-UTR under the control of the cytomegalovirus promoter. The expression vector was transfected into Calu-3 cells and treated with IFN-α and the IFNAR2 agonist CDM-3008 (RO8191) for 3 days. SARS-CoV-2 subreplicon RNA degradation was subsequently evaluated based on luciferase levels. IFN-α and CDM-3008 suppressed SARS-CoV-2 subreplicon RNA in a dose-dependent manner, with IC50 values of 193 IU/mL and 2.54 µM, respectively. HeLa cells stably expressing SARS-CoV-2 subreplicon RNA were prepared and treated with the IFN-α and pan-JAK inhibitor Pyridone 6 or siRNA-targeting ISG20. IFN-α activity was canceled with Pyridone 6. The knockdown of ISG20 partially canceled IFN-α activity. Collectively, we constructed a virus-free rapid detection system to measure SARS-CoV-2 RNA suppression. Our data suggest that the SARS-CoV-2 subreplicon RNA was degraded by IFN-α-induced ISG20 exonuclease activity.

Remdesivir overcomes the S861 roadblock in SARS-CoV-2 polymerase elongation complex.

Remdesivir (RDV), a nucleotide analog with broad-spectrum features, has exhibited effectiveness in COVID-19 treatment. However, the precise working mechanism of RDV when targeting the viral RNA-dependent RNA polymerase (RdRP) has not been fully elucidated. Here, we solve a 3.0-Å structure of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RdRP elongation complex (EC) and assess RDV intervention in polymerase elongation phase. Although RDV could induce an "i+3" delayed termination in meta-stable complexes, only pausing and subsequent elongation are observed in the EC. A comparative investigation using an enterovirus RdRP further confirms similar delayed intervention and demonstrates that steric hindrance of the RDV-characteristic 1'-cyano at the -4 position is responsible for the "i+3" intervention, although two representative Flaviviridae RdRPs do not exhibit similar behavior. A comparison of representative viral RdRP catalytic complex structures indicates that the product RNA backbone encounters highly conserved structural elements, highlighting the broad-spectrum intervention potential of 1'-modified nucleotide analogs in anti-RNA virus drug development.

Remdesivir for the treatment of Covid-19: the value of biochemical studies.

The nucleotide analogue prodrug remdesivir remains the only FDA-approved antiviral small molecule for the treatment of infection with SARS-CoV-2. Biochemical studies revealed that the active form of the drug targets the viral RNA-dependent RNA polymerase and causes delayed chain-termination. Delayed chain-termination is incomplete, but the continuation of RNA synthesis enables a partial escape from viral proofreading. Remdesivir becomes embedded in the copy of the RNA genome that later serves as a template. Incorporation of an incoming nucleotide triphosphate is now inhibited by the modified template. Knowledge on the mechanism of action matters. Enzymatic inhibition links to antiviral effects in cell cultures, animal models and viral load reduction in patients, which provides the logical chain that is expected for a direct acting antiviral. Hence, remdesivir also serves as a benchmark in current drug development efforts that will hopefully lead to orally available treatments to the benefit of a broader population.

Efficacy and safety assessment of severe COVID-19 patients with Chinese medicine: A retrospective case series study at early stage of the COVID-19 epidemic in Wuhan, China.

ETHNOPHARMACOLOGICAL RELEVANCE: The coronavirus disease 2019 (COVID-19) has formed a global pandemic since late 2019. Benefitting from the application experience of Chinese Medicine (CM) for influenza and SARS, CM has been used to save patients at the early stage of COVID-19 outbreak in China. AIM OF THE STUDY: In order to evaluate the efficacy and safety of CM, and compare with Western Medicine (WM) for COVID-19, we conducted a retrospective case series study based on the patients in Wuhan Jinyintan Hospital, Wuhan, China. METHODS: The inclusion and exclusion criteria of data extraction were set for this retrospective study. All patients who were admitted by the Wuhan Jinyintan Hospital between January 17th and February 25th 2020 were considered. In addition, patients enrolled met the severe defined by the guidelines released by the National Health Commission of the People's Republic of China. In these cases included in the study, CM or WM treatment was selected according to the wishes of the patients at the beginning of hospitalization. The patients in CM group were treated with Huashi Baidu granule (137 g po, bid) combined with the injections of Xiyanping (100 mg iv, bid), Xuebijing (100 ml iv, bid) and Shenmai (60 ml iv, qd) according to the syndrome of epidemic toxin blocking the lung in the theory of Traditional Chinese Medicine. The WM group received antiviral therapy (including abidor capsule 0.2 g po, tid; Lopinavir-Ritonavir tablets, 500 mg po, bid), antibiotics (such as cefoperazone 2 g iv, bid; moxifloxacin hydrochloride tablets, 0.4 g po, qd) or corticosteroid therapy (such as methylprednisolone succinate sodium 40 mg iv, qd; prednisone, 30 mg po, qd). In addition, patients in both groups received routine supportive treatment, including oxygen inhalation, symptomatic therapy, and/or human intravenous immunoglobulin, and/or serum albumin, and treatment for underlying diseases. The clinical outcomes were evaluated based on changes related with clinical manifestations, computer tomography (CT) scan images, and laboratory examinations before and after the treatment. RESULTS: 55 severe COVID-19 patients, with 23 in CM group and 32 in WM group, were included for analyzed. There was no case of death, being transferred to ICU, or receiving invasive mechanical ventilation in two groups during hospitalization. The median time of SARS-CoV-2 RNA clearance in CM and WM group were 12 days and 15.5 days respectively, the ratio of nucleic acid negative conversion of CM group at different follow-up time points was significantly higher than that of WM group (HR: 2.281, P = 0.018). Further, the chest CT imaging showed more widely lung lesion opacity absorbed in the CM group. The high sensitivity C-reactive protein and serum ferritin decreased significantly in the CM group (P<0.05). There was no significant difference in adverse events in terms of liver function and renal function between the two groups. CONCLUSION: Based on this retrospective analysis from Wuhan Jinyintan Hospital, CM has better effects in SARS-CoV-2 RNA clearance, promoting lung lesion opacity absorbed and reducing inflammation in severe COVID-19 patients, which is effective and safe therapy for treating severe COVID-19 and reducing mortality.

Increased Proviral DNA in Circulating Cells Correlates with Plasma Viral Rebound in Simian Immunodeficiency Virus-Infected Rhesus Macaques after Antiretroviral Therapy Interruption.

The human immunodeficiency virus (HIV) reservoir is responsible for persistent viral infection, and a small number of mosaic latent cellular reservoirs promote viral rebound upon antiretroviral therapy interruption, which is the major obstacle to a cure. However, markers that determine effective therapy and viral rebound posttreatment interruption remain unclear. In this study, we comprehensively and longitudinally tracked dynamic decay of cell-associated viral RNA/DNA in systemic and lymphoid tissues in simian immunodeficiency virus (SIV)-infected rhesus macaques on prolonged combined antiretroviral therapy (cART) and evaluated predictors of viral rebound after treatment cessation. The results showed that suppressive ART substantially reduced plasma SIV RNA, cell-associated unspliced, and multiply spliced SIV RNA to undetectable levels, yet viral DNA remained detectable in systemic tissues and lymphoid compartments throughout cART. Intriguingly, a rapid increase of integrated proviral DNA in peripheral mononuclear cells was detected once treatment was withdrawn, accompanied by the emergence of detectable plasma viral load. Notably, the increase of peripheral proviral DNA after treatment interruption correlated with the emergence and degree of viral rebound. These findings suggest that measuring total viral DNA in SIV infection may be a relatively simple surrogate marker of reservoir size and may predict viral rebound after treatment interruption and inform treatment strategies.IMPORTANCE Viral reservoirs are involved in persistent HIV infection, and a small number of mosaic latent cellular reservoirs promote viral rebound upon analytical treatment interruption, which is the major obstacle to a cure. However, early indicators that can predict resurgence of viremia after treatment interruption may aid treatment decisions in people living with HIV. Utilizing the rhesus macaque model, we demonstrated that increased proviral DNA in peripheral cells after treatment interruption, rather than levels of proviral DNA, was a useful marker to predict the emergence and degree of viral rebound after treatment interruption, providing a rapid approach for monitoring HIV rebound and informing decisions.

Usefulness of Plasma SARS-CoV-2 RNA Quantification by Droplet-based Digital PCR to Monitor Treatment Against COVID-19 in a B-cell Lymphoma Patient.

We report the case of an HIV-1-infected patient, treated with anti-CD20 monoclonal antibody for a B-cell lymphoma previously treated by autologous stem cell transplant. He suffered from chronic COVID19 and we monitored by plasma SARS-CoV-2 RNA by highly sensitive droplet-based digital PCR technology (ddPCR). Under tocilizumab therapy and despite a first clinical improvement biologically associated with decreasing inflammatory markers, a slight increase of SARS-CoV-2 RNAaemia quantified by ddPCR was highlighted, confirming the absence of viral efficacy of this treatment and predicting the subsequent observed deterioration. As expected, his complete recovery, finally achieved after COVID-19 convalescent plasmatherapy, strictly paralleled plasma SARS-CoV-2 RNA clearance. With these results, we confirmed the interest of SARS-CoV-2 RNAaemia monitoring by ddPCR in COVID-19 patients, particularly during treatment, and firstly showed that this new and specific biomarker could be helpful to select eligible patient for anti-IL6 receptors therapy considering the variable levels of efficacy recently observed with such therapy.

Remdesivir: Critical Clinical Appraisal for COVID 19 Treatment.

Remdesivir is presently been considered as 'molecule of hope' to curb the menace of COVID19. Non-availability of any USFDA approved drug has led to several attempt of drug-repurposing and development of new therapeutic molecules. However, Remdesivir has been found to be effective against a broad range of virus including SARS, MERS and COVID 19 through in-vitro studies. Several clinical research attempt are presently being conducted showing promising result yet not conclusive. This review summarized all such clinical trials to critically appraise the usage of Remdesivir against COVID 19 along with the publications related to the results of the clinical studies. The present regulatory aspect i. e. Emergency Use Authorization (EYA) and information of molecule and plausible mechanism is also dealt.

MCPIP1 reduces HBV-RNA by targeting its epsilon structure.

Hepatitis B virus (HBV) is the major causative factor of chronic viral hepatitis, liver cirrhosis, and hepatocellular carcinoma. We previously demonstrated that a proinflammatory cytokine IL-1ß reduced the level of HBV RNA. However, the mechanism underlying IL-1ß-mediated viral RNA reduction remains incompletely understood. In this study, we report that immune regulator Monocyte chemotactic protein-1-induced protein 1 (MCPIP1) can reduce HBV RNA in hepatocytes. MCPIP1 expression level was higher in the liver tissue of HBV-infected patients and mice. Overexpression of MCPIP1 decreased HBV RNA, whereas ablating MCPIP1 in vitro enhanced HBV production. The domains responsible for RNase activity or oligomerization, were required for MCPIP1-mediated viral RNA reduction. The epsilon structure of HBV RNA was important for its antiviral activity and cleaved by MCPIP1 in the cell-free system. Lastly, knocking out MCPIP1 attenuated the anti-HBV effect of IL-1ß, suggesting that MCPIP1 is required for IL-1ß-mediated HBV RNA reduction. Overall, these results suggest that MCPIP1 may be involved in the antiviral effect downstream of IL-1ß.

Sofosbuvir terminated RNA is more resistant to SARS-CoV-2 proofreader than RNA terminated by Remdesivir.

SARS-CoV-2 is responsible for COVID-19, resulting in the largest pandemic in over a hundred years. After examining the molecular structures and activities of hepatitis C viral inhibitors and comparing hepatitis C virus and coronavirus replication, we previously postulated that the FDA-approved hepatitis C drug EPCLUSA (Sofosbuvir/Velpatasvir) might inhibit SARS-CoV-2. We subsequently demonstrated that Sofosbuvir triphosphate is incorporated by the relatively low fidelity SARS-CoV and SARS-CoV-2 RNA-dependent RNA polymerases (RdRps), serving as an immediate polymerase reaction terminator, but not by a host-like high fidelity DNA polymerase. Other investigators have since demonstrated the ability of Sofosbuvir to inhibit SARS-CoV-2 replication in lung and brain cells; additionally, COVID-19 clinical trials with EPCLUSA and with Sofosbuvir plus Daclatasvir have been initiated in several countries. SARS-CoV-2 has an exonuclease-based proofreader to maintain the viral genome integrity. Any effective antiviral targeting the SARS-CoV-2 RdRp must display a certain level of resistance to this proofreading activity. We report here that Sofosbuvir terminated RNA resists removal by the exonuclease to a substantially higher extent than RNA terminated by Remdesivir, another drug being used as a COVID-19 therapeutic. These results offer a molecular basis supporting the current use of Sofosbuvir in combination with other drugs in COVID-19 clinical trials.

New Anti SARS-Cov-2 Targets for Quinoline Derivatives Chloroquine and Hydroxychloroquine.

The rapid spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has created a severe global health crisis. In this paper, we used docking and simulation methods to identify potential targets and the mechanism of action of chloroquine (CQ) and hydroxychloroquine (HCQ) against SARS-CoV-2. Our results showed that both CQ and HCQ influenced the functionality of the envelope (E) protein, necessary in the maturation processes of the virus, due to interactions that modify the flexibility of the protein structure. Furthermore, CQ and HCQ also influenced the proofreading and capping of viral RNA in SARS-CoV-2, performed by nsp10/nsp14 and nsp10/nsp16. In particular, HCQ demonstrated a better energy binding with the examined targets compared to CQ, probably due to the hydrogen bonding of the hydroxyl group of HCQ with polar amino acid residues.

Clinical characteristics and corticosteroids application of different clinical types in patients with corona virus disease 2019.

To describe the epidemiological and clinical characteristics of patients with Corona Virus Disease 2019 (COVID-19) in Beijing. To analyze the application of corticosteroids in patients with severe pneumonia. We collected information on demographic characteristics, exposure history, clinical characteristics, corticosteroids use, and outcomes of the 65 confirmed cases of COVID-19 at Fifth Medical Center of PLA General Hospital from Jan 20 to Feb 23, 2020. The final follow-up date observed was April 15th, 2020. The number of patients with mild, general, severe, and critical type were 10 (15.38%), 32 (49.23%), 8 (12.31%), and 15 (23.08%), respectively. The median incubation period was 6 days. Notable outliers were 1 patient at 16 days and 1 patient at 21 days. In lymphocyte subgroup analysis, decreases in total, T, CD4, and CD8 lymphocytes were more common as the disease worsened (All P < 0.05). Methylprednisolone (mPSL) was applied to 31 (47.69%) patients with pneumonia, including 10 (31.25%) general, 8 (100%) severe, and 13 (86.67%) critical patients, respectively. Corticosteroids inhibited Interleukin-6(IL-6) production (P = 0.0215) but did not affect T lymphocyte (P = 0.0796). There was no significant difference between patients using lower dose (≤ 2 mg/kg day) and higher dose (> 2 mg/kg day) mPSL in inhibiting IL-6 production (P = 0.5856). Thirty of 31 patients (96.77%) had stopped mPSL due to improvement of pneumonia. Virus RNA clearance time lengthened with disease progression (P = 0.0001). In general type, there was no significant difference in virus clearance time between patients with (15, 12-19 days) and without (14.5, 11-18 days) (P = 0.7372) mPSL use. Lymphocyte, especially T lymphocyte, in severe and critical patients showed a dramatic decrease. Application of lower dose corticosteroids (≤ 2 mg/kg day) could inhibit IL-6 production (a representative of cytokines) as effectively as a higher dose. Proper use corticosteroids in general type patients did not delay virus clearance.

CXCL9 chemokine level is associated with spontaneous clearance and sustained virological response in Egyptian Chronic Hepatitis C patients receiving direct acting antivirals.

BACKGROUND: Chronic Hepatitis C virus (HCV) infection is associated with progressive liver inflammation which in turn leads to cirrhosis and finally causes hepatocellular carcinoma (HCC). By different escape mechanisms, the virus succeeds to evade the innate and acquired immune responses to establish chronic infection. AIM: This study aimed to evaluate the level of chemokine CXCL9 and its correlation with some biochemical parameters in different subjects of HCV patients. MATERIALS AND METHODS: A total of 83 persons participated in this study including healthy subjects without both HCV antibodies and HCV RNA (22.9%), HCV treated responders accomplished SVR post treatment, with HCV antibodies and absence of HCV RNA (24.1%), spontaneous or natural clearance patients, with positive HCV antibodies and negative HCV RNA without treatment (26.5%) and chronic HCV-patients, with both positive HCV antibodies and HCV RNA with no treatment (26.5%). HCV RNA was quantitated by real time PCR and serum CXCL9 level was measured by ELISA commercial kit pre-coated with human MIG/CXCL9 antibody. Assessment of biochemical and hematological parameters was carried out. RESULTS: Data showed that, the level of CXCL9 was significantly increased in chronic individuals (627.1 pg/ml) (P< 0.001) than spontaneous clearance (107.76 pg/ml) and responder subjects (117.28 pg/ml) (P⩽ 0.05). No correlation has been found between CXCL9 level and viral load. Furthermore, CXCL9 levels correlated variably with some biochemical and hematological parameters according to each subject. CONCLUSION: Serum Chemokine CXCL9 level is associated with spontaneous clearance of HCV and response to HCV treatment, which may be identified as a predictive marker among HCV patients.

Symmetric benzidine derivatives as anti-HCV agents: Insight into the nature, stereochemistry of the capping amino acid and the size of the terminal capping carbamates.

Novel symmetric molecules, bearing a benzidine prolinamide core, two terminal carbamate caps of variable sizes and nature, including natural and unnatural amino acids were developed. Several terminal N-carbamate substituents of the core structure, ranging from linear methyl, ethyl and butyl groups to branching isobutyl group; and an aromatic substituent were also synthesized. Series 1 has hydrophobic AA residues, namely S and R phenylglycine and a terminal carbamate capping group, whereas Series 2 bears sulphur containing amino acids, specifically S and R methionine and the natural R methylcysteine. The novel compounds were tested for their inhibitory activity (EC50) and their cytotoxicity (CC50), using an HCV 1b (Con1) reporter replicon cell line. Compound 4 with the unnatural capping residue, bearing d-Phenylglycine amino acid residue and N-isobutyloxycarbonyl capping group, was the most active within the two series, with EC50 = 0.0067 nM. Moreover, it showed high SI50 > 14788524 and was not cytotoxic at the highest tested concentration (100 µΜ), indicating its safety profile. Compound 4 also inhibited HCV genotypes 2a, 3a and 4a. Compared to the clinically approved NS5A inhibitor Daclatasvir, compound 4 shows higher activity against genotypes 1b and 3a, as well as improved safety profile.

Immune Checkpoint Inhibitor Can Reduce HCV-RNA without Liver Damage.

Recently, immune checkpoint inhibitors (iCIs) have been used to treat cancers. Once some of the iCIs for the treatment of hepatocellular carcinoma (HCC) are certified in clinical trials, they are likely be administered to HCC patients with hepatitis C virus (HCV). However, the immunopathogenesis of HCV after the administration of iCIs has not been clarified. We experienced a lung cancer patient with HCV infection treated by nivolumab, programmed cell death 1 (PD-1) antibody. HCV-RNA gradually decreased after the start of nivolumab treatment. However, no increase in transaminase was observed during the decline of HCV-RNA. It was thought that HCV-specific cytotoxic T lymphocytes (CTLs) were activated by iCIs.

Oral Methioninase for Covid-19 Methionine-restriction Therapy.

The Covid-19 pandemic is a world-wide crisis without an effective therapy. While most approaches to therapy are using repurposed drugs that were developed for other diseases, it is thought that targeting the biology of the SARS-CoV-2 virus, which causes Covid-19, can result in an effective therapeutic treatment. The coronavirus RNA cap structure is methylated by two viral methyltransferases that transfer methyl groups from S-adenosylmethionine (SAM). The proper methylation of the virus depends on the level of methionine in the host to form SAM. Herein, we propose to restrict methionine availability by treating the patient with oral recombinant methioninase, aiming to treat Covid-19. By restricting methionine we not only interdict viral replication, which depends on the viral RNA cap methyaltion, but also inhibit the proliferation of the infected cells, which have an increased requirement for methionine. Most importantly, the virally-induced T-cell- and macrophage-mediated cytokine storm, which seems to be a significant cause for Covid-19 deaths, can also be inhibited by restricting methionine, since T-cell and macrophrage activation greatly increases the methionine requirement for these cells. The evidence reviewed here suggests that oral recombinant methioninase could be a promising treatment for coronavirus patients.