Efficacy and Mechanism of Action of Low Dose Emetine against Human Cytomegalovirus

PLoS Pathogens

Rupkatha Mukhopadhyay¹  Rajkumar Venkatadri¹  Yu-Pin Su¹  Ravit Arav-Boger¹  Sujayita Roy¹  Elena Barnaeva²  Juan J. Marugan²  Xin Xu²  Noel Southall²  Lesley Mathews Griner²  Amy Q. Wang²  Marc Ferrer²  Wenjuan Ye²  Xin Hu²  Andrés E. Dulcey² 

[1] Department of Pediatrics, Division of Infectious Diseases, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America;National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland, United States of America

关键词: Human cytomegalovirus;    Immunoblotting;    Viral replication;    Cell disruption;    Fluorescence microscopy;    Luciferase;    Luciferase assay;    Cytomegalovirus infection;   

DOI  :  10.1371/journal.ppat.1005717

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

Infection with human cytomegalovirus (HCMV) is a threat for pregnant women and immunocompromised hosts. Although limited drugs are available, development of new agents against HCMV is desired. Through screening of the LOPAC library, we identified emetine as HCMV inhibitor. Additional studies confirmed its anti-HCMV activities in human foreskin fibroblasts: EC50−40±1.72 nM, CC50−8±0.56 μM, and selectivity index of 200. HCMV inhibition occurred after virus entry, but before DNA replication, and resulted in decreased expression of viral proteins. Synergistic virus inhibition was achieved when emetine was combined with ganciclovir. In a mouse CMV (MCMV) model, emetine was well-tolerated, displayed long half-life, preferential distribution to tissues over plasma, and effectively suppressed MCMV. Since the in vitro anti-HCMV activity of emetine decreased significantly in low-density cells, a mechanism involving cell cycle regulation was suspected. HCMV inhibition by emetine depended on ribosomal processing S14 (RPS14) binding to MDM2, leading to disruption of HCMV-induced MDM2-p53 and MDM2-IE2 interactions. Irrespective of cell density, emetine induced RPS14 translocation into the nucleus during infection. In infected high-density cells, MDM2 was available for interaction with RPS14, resulting in disruption of MDM2-p53 interaction. However, in low-density cells the pre-existing interaction of MDM2-p53 could not be disrupted, and RPS14 could not interact with MDM2. In high-density cells the interaction of MDM2-RPS14 resulted in ubiquitination and degradation of RPS14, which was not observed in low-density cells. In infected-only or in non-infected emetine-treated cells, RPS14 failed to translocate into the nucleus, hence could not interact with MDM2, and was not ubiquitinated. HCMV replicated similarly in RPS14 knockdown or control cells, but emetine did not inhibit virus replication in the former cell line. The interaction of MDM2-p53 was maintained in infected RPS14 knockdown cells despite emetine treatment, confirming a unique mechanism by which emetine exploits RPS14 to disrupt MDM2-p53 interaction. Summarized, emetine may represent a promising candidate for HCMV therapy alone or in combination with ganciclovir through a novel host-dependent mechanism.

【 授权许可】

CC BY