Alternative screening approaches for discovery of Middle East respiratory syndrome coronavirus inhibitors.

Two coronaviruses causing severe respiratory disease and high mortality rates emerging within the past dozen years reinforces the need for clinically efficacious antivirals targeting coronaviruses. Alternative screening approaches for antivirals against the recently emergent Middle East respiratory syndrome coronavirus (MERS-CoV) may provide lead compounds to address this need. Two Antimicrobial Agents and Chemotherapy (AAC) papers screened libraries of approved compounds that may potentially be repurposed as MERS-CoV antivirals.

A genotype 2b NS5B polymerase with novel substitutions supports replication of a chimeric HCV 1b:2b replicon containing a genotype 1b NS3-5A background.

HCV diversity suggests that evaluation of HCV inhibitors for broad genotypic efficacy is warranted. The replicon system enables cell-culture compound efficacy evaluation against an active replication complex, and a functional replicon dependent upon a genotype 2b polymerase would augment existing cell-culture efficacy studies that are presently limited to genotype 1a, 1b, and 2a replicons. We made a chimeric Neo(r) 1b:2b replicon where genotype 2b NS5B was inserted into a genotype 1b NS3-5A background and transfected replicon RNA to generate Neo(r) cell lines.

Replication fitness and NS5B drug sensitivity of diverse hepatitis C virus isolates characterized by using a transient replication assay.

The innate genetic variability characteristic of chronic hepatitis C virus (HCV) infection makes drug resistance a concern in the clinical development of HCV inhibitors. To address this, a transient replication assay was developed to evaluate the replication fitness and the drug sensitivity of NS5B sequences isolated from the sera of patients with chronic HCV infection. This novel assay directly compares replication between NS5B isolates, thus bypassing the potential sequence and metabolic differences which may arise with independent replicon cell lines.

Structure-activity relationship of heterobase-modified 2'-C-methyl ribonucleosides as inhibitors of hepatitis C virus RNA replication.

Hepatitis C virus infection constitutes a significant health problem in need of more effective therapies. We have recently identified 2'-C-methyladenosine and 2'-C-methylguanosine as potent nucleoside inhibitors of HCV RNA replication in vitro. However, both of these compounds suffered from significant limitations.

A 7-deaza-adenosine analog is a potent and selective inhibitor of hepatitis C virus replication with excellent pharmacokinetic properties.

Improved treatments for chronic hepatitis C virus (HCV) infection are needed due to the suboptimal response rates and deleterious side effects associated with current treatment options. The triphosphates of 2'-C-methyl-adenosine and 2'-C-methyl-guanosine were previously shown to be potent inhibitors of the HCV RNA-dependent RNA polymerase (RdRp) that is responsible for the replication of viral RNA in cells. Here we demonstrate that the inclusion of a 7-deaza modification in a series of purine nucleoside triphosphates results in an increase in inhibitory potency against the HCV RdRp and improved pharmacokinetic properties.