ABSTRACT
Autophagy, a cellular surveillance mechanism, plays an important role in combating invading pathogens. However, viruses have evolved various strategies to disrupt autophagy and even hijack it for replication and release. Here, we demonstrated that Middle East respiratory syndrome coronavirus (MERS-CoV) non-structural protein 1(nsp1) induces autophagy but inhibits autophagic activity. MERS-CoV nsp1 expression increased ROS and reduced ATP levels in cells, which activated AMPK and inhibited the mTOR signalling pathway, resulting in autophagy induction. Meanwhile, as an endonuclease, MERS-CoV nsp1 downregulated the mRNA of lysosome-related genes that were enriched in nsp1-located granules, which diminished lysosomal biogenesis and acidification, and inhibited autophagic flux. Importantly, MERS-CoV nsp1-induced autophagy can lead to cell death in vitro and in vivo. These findings clarify the mechanism by which MERS-CoV nsp1-mediated autophagy regulation, providing new insights for the prevention and treatment of the coronavirus.
Subject(s)
Middle East Respiratory Syndrome Coronavirus , Middle East Respiratory Syndrome Coronavirus/physiology , AMP-Activated Protein Kinases/metabolism , Reactive Oxygen Species/metabolism , RNA, Messenger/metabolism , Lysosomes/metabolism , Autophagy , Endonucleases/metabolism , TOR Serine-Threonine Kinases/genetics , TOR Serine-Threonine Kinases/metabolism , Adenosine Triphosphate/metabolismABSTRACT
The outbreak of the monkeypox virus (MPXV) in non-endemic countries is an emerging global health threat and may have an economic impact if proactive actions are not taken. As shown by the COVID-19 pandemic, rapid, accurate, and cost-effective virus detection techniques play a pivotal role in disease diagnosis and control. Considering the sudden multicountry MPXV outbreak, a critical evaluation of the MPXV detection approaches would be a timely addition to the endeavors in progress for MPXV control and prevention. Herein, we evaluate the current MPXV detection methods, discuss their pros and cons, and provide recommended solutions to the problems. We review the traditional and emerging nucleic acid detection approaches, immunodiagnostics, whole-particle detection, and imaging-based MPXV detection techniques. The insights provided in this article will help researchers to develop novel techniques for the diagnosis of MPXV.
ABSTRACT
MERS-CoV infection can damage the cellular metabolic processes, but the underlying mechanisms are largely unknown. Through screening, we found non-structural protein 1 (nsp1) of MERS-CoV could inhibit cell viability, cell cycle, and cell migration through its endonuclease activity. Transcriptome sequencing revealed that MERS-CoV nsp1 specifically downregulated the mRNAs of ribosomal protein genes, oxidative phosphorylation protein genes, and antigen presentation genes, but upregulated the mRNAs of transcriptional regulatory genes. Further analysis shown nsp1 existed in a novel ribonucleosome complex formed via liquid-liquid phase separation, which did not co-localize with mitochondria, lysosomes, P-bodies, or stress granules. Interestingly, the nsp1-located granules specifically contained mRNAs of ribosomal protein genes and oxidative phosphorylation genes, which may explain why MERS-CoV nsp1 selectively degraded these mRNAs in cells. Finally, MERS-CoV nsp1 transgenic mice showed significant loss of body weight and an increased sensitivity to poly(I:C)-induced inflammatory death. These findings demonstrate a new mechanism by which MERS-CoV impairs cell viability, which serves as a potential novel target for preventing MERS-CoV infection-induced pathological damage.Abbreviations: (Middle East respiratory syndrome coronavirus (MERS-CoV), Actinomycin D (Act D), liquid-liquid phase separation (LLPS), stress granules (SGs), Mass spectrometry (IP-MS), RNA Binding Protein Immunoprecipitation (RIP)).