RESUMO
The host restriction factor APOBEC3G (A3G) inhibits an extensive variety of viruses, including retroviruses, DNA viruses, and RNA viruses. Our study shows that A3G inhibits enterovirus 71 (EV71) and coxsackievirus A16 (CA16) via competitively binding the 5' untranslated region (UTR) with the host protein poly(C)-binding protein 1 (PCBP1), which is required for the replication of multiple EVs. However, whether A3G inhibits other EVs in addition to EV71 and CA16 has not been investigated. Here, we demonstrate that A3G could inhibit the replication of EVD68, which requires PCBP1 for its replication, but not CA6, which does not require PCBP1 for replication. Further investigation revealed that the nucleic-acid-binding activity of A3G is required for EVD68 restriction, similar to the mechanism presented for EV71 restriction. Mechanistically, A3G competitively binds to the cloverleaf (1 to 123 nucleotides [nt]) and the stem-loop IV (234 to 446 nt) domains of the EVD68 5' UTR with PCBP1, thereby inhibiting the 5' UTR activity of EVD68; by contrast, A3G does not interact with CA6 5' UTR, resulting in no effect on CA6 replication. Moreover, the nonstructural protein 2C, encoded by EVD68, overcomes A3G suppression by inducing A3G degradation via the autophagy-lysosome pathway. Our findings revealed that A3G might have broad-spectrum antiviral activity against multiple EVs through this general mechanism, and they might provide important information for the development of an anti-EV strategy. IMPORTANCE As the two major pathogens causing hand, foot, and mouth disease (HFMD), enterovirus 71 (EV71) and coxsackievirus A16 (CA16) attract a lot of attention for the study of their pathogenesis, their involvement with cellular proteins, and so on. However, other EVs such as CA6 and EVD68 constantly occur sporadically or have spread worldwide in recent years. Therefore, more information related to these EVs is needed in order to develop a broad-spectrum anti-EV inhibitor. In this study, we first reveal that the protein poly(C)-binding protein 1 (PCBP1), involved in PV- and EV71 virus replication, is also required for the replication of EVD68, but not for the replication of CA6. Next, we found that the host-restriction factor A3G specifically inhibits the replication of EVD68, but not the replication of CA6, by competitively binding to the 5' UTR of EVD68 along with PCBP1. Our findings broaden knowledge related to EV replication and the interplay between EVs and host factors.
Assuntos
Regiões 5' não Traduzidas/fisiologia , Desaminase APOBEC-3G/metabolismo , Proteínas de Ligação a DNA/metabolismo , Enterovirus Humano D/fisiologia , Proteínas de Ligação a RNA/metabolismo , Replicação Viral , Desaminase APOBEC-3G/genética , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Proteínas de Ligação a DNA/genética , Enterovirus Humano A/fisiologia , Células HEK293 , Humanos , Conformação de Ácido Nucleico , RNA Viral/química , RNA Viral/genética , RNA Viral/metabolismo , Proteínas de Ligação a RNA/genética , Proteínas não Estruturais Virais/genética , Proteínas não Estruturais Virais/metabolismoRESUMO
Enterovirus D68 (EVD68) is an emerging pathogen that recently caused a large worldwide outbreak of severe respiratory disease in children. However, the relationship between EVD68 and host cells remains unclear. Caspases are involved in cell death, immune response, and even viral production. We found that caspase-3 was activated during EVD68 replication to induce apoptosis. Caspase-3 inhibitor (Z-DEVD-FMK) inhibited viral production, protected host cells from the cytopathic effects of EVD68 infection, and prevented EVD68 from regulating the host cell cycle at G0/G1. Meanwhile, caspase-3 activator (PAC-1) increased EVD68 production. EVD68 infection therefore activates caspase-3 for virus production. This knowledge provides a potential direction for the prevention and treatment of disease related to EVD68.
Assuntos
Antivirais/farmacologia , Caspase 3/efeitos dos fármacos , Caspase 3/metabolismo , Enterovirus Humano D/efeitos dos fármacos , Enterovirus Humano D/crescimento & desenvolvimento , Apoptose/fisiologia , Linhagem Celular Tumoral , Infecções por Enterovirus/patologia , Infecções por Enterovirus/prevenção & controle , Infecções por Enterovirus/virologia , Pontos de Checagem da Fase G1 do Ciclo Celular/efeitos dos fármacos , Humanos , Hidrazonas/farmacologia , Oligopeptídeos/farmacologia , Piperazinas/farmacologiaRESUMO
Human enterovirus 68 (EVD68) is a primary causative agent for respiratory illness worldwide. Until now, there has been no available medication for treating EVD68-related diseases. Rheum emodin, artemisinin, astragaloside, pseudolaric acid B, oridonin, and erianin are natural extracts from Chinese herbs that have traditionally been used for the treatment and prevention of epidemic diseases. Our results showed that pseudolaric acid B protected cells from EVD68-induced cytopathic effects and decreased viral production. However, the same effects were not observed with rheum emodin, astragaloside, or artemisinin. Pseudolaric acid B inhibited EVD68 production by manipulating the host cell cycle in G2/M phase. Further, either oridonin or erianin related G2/M arrest also inhibited viral production. Due to inducing G2/M phase arrest, pseudolaric acid B, oridonin, and erianin might be good candidates for inhibiting EVD68 production, and Chinese herbs with natural compounds inducing G2/M arrest should be considered for the treatment of EVD68-related diseases.