Facile synthesis of photoactivatable adenosine analogs

Photoactivatable adenosine analog-enabled capture and enrichment of adenosine binding protein (ABP).

Antigen-Specific T Cell Recall Assay To Screen Drugs For Off-Target Effects

ABSTRACTExtracellular adenosine suppresses T cell immunity in the tumor microenvironment. We have developed an in vitro recall assay utilizing a sequential adenosine dosing regimen guide for testing drug off-target effects on memory T cell expansion/function. As a proof of principle, we show low dose adenosine analog GS-5734, a monophosphoramidate prodrug of an adenosine analog, does not alter memory T cell recall whereas toxicity observed at high dose favors antigen-specific memory T cell survival/proliferation over non-specific CD8+ T cells. Parent drug GS-445124 at high dosage interferes with antigen-specific T cell recall without cellular toxicity. Despite similar chemical structure, these drugs displayed opposing effects on memory T cell expansion. This assay platform has broad utility in screening memory T cell off-target effects.

Remdesivir (GS-5734) Impedes Enterovirus Replication Through Viral RNA Synthesis Inhibition

Human enteroviruses are responsible for diverse diseases, from mild respiratory symptoms to fatal neurological complications. Currently, no registered antivirals have been approved for clinical therapy. Thus, a therapeutic agent for the enterovirus-related disease is urgently needed. Remdesivir (GS-5734) is a novel monophosphoramidate adenosine analog prodrug that exhibits potent antiviral activity against diverse RNA virus families, including positive-sense Coronaviridae and Flaviviridae and negative-sense Filoviridae, Paramyxoviridae, and Pneumoviridae. Currently, remdesivir is under phase 3 clinical development for disease COVID-19 treatment. Here, we found that remdesivir impeded both EV71 viral RNA (vRNA) and complementary (cRNA) synthesis, indicating that EV71 replication is inhibited by the triphosphate (TP) form of remdesivir. Moreover, remdesivir showed potent antiviral activity against diverse enteroviruses. These data extend the remdesivir antiviral activity to enteroviruses and indicate that remdesivir is a promising antiviral treatment for EV71 and other enterovirus infections.

Adenosine Analog NITD008 Is a Potent Inhibitor of Zika Virus

The ongoing Zika virus (ZIKV) outbreaks have raised global concerns due to its unexpected clinical manifestations. Antiviral development is of high priority in response to the ZIKV emergency. In this study, we report that an adenosine analog NITD008 has potent in vitro and in vivo antiviral activity against ZIKV. The compound can effectively inhibit the historical and contemporary ZIKV strains in cultures as well as significantly reduce viremia and prevent mortality in A129 mice. Our results have demonstrated that NITD008 is potent inhibitor of ZIKV and can be used as reference inhibitor for future ZIKV antiviral drug screen and discovery.