The translational landscape of SARS-CoV-2 and infected cells (preprint)

SARS-CoV-2, a betacoronavirus with a positive-sense RNA genome, has caused the ongoing COVID-19 pandemic. Although a large number of transcriptional profiling studies have been conducted in SARS-CoV-2 infected cells, little is known regarding the translational landscape of host and viral proteins. Here, using ribosome profiling in SARS-CoV-2-infected cells, we identify structural elements that regulate viral gene expression, alternative translation initiation events, as well as host responses regulated by mRNA translation. We found that the ribosome density was low within the SARS-CoV-2 frameshifting element but high immediately downstream, which suggests the utilization of a highly efficient ribosomal frameshifting strategy. In SARS-CoV-2-infected cells, although many chemokine, cytokine and interferon stimulated genes were upregulated at the mRNA level, they were not translated efficiently, suggesting a translational block that disarms host innate host responses. Together, these data reveal the key role of mRNA translation in SARS-CoV-2 replication and highlight unique mechanisms for therapeutic development.

Identification, Isolation, Propagation And Inactivation Of SARS-CoV2 Isolated From Egypt (preprint)

Severe Acute Respiratory Syndrome Coronavirus 2 causes the novel pandemic Pneumonia disease. It is a positive single strand ssRNA virus that infect human. COVID-19 appeared in Egypt in Feb 2020. The samples were taken from patients with COVID-19 symptoms at military hospital in Egypt and transported to the main chemical laboratories under all the biosafety measures according to WHO guidelines. All samples were tested with RT-PCR. Positive samples were cultured using VeroE6 cell lines. The propagated virus was isolated and inactivated. The isolated virus was sequenced using next generation sequencing and submitted into gene bank. This study provides an isolation, propagation and inactivation methodology which is valuable for production of inactivated vaccines against SARS-CoV2 in Egypt.

SARS-CoV-2 Infects Human Engineered Heart Tissues and Models COVID-19 Myocarditis (preprint)

Epidemiological studies of the COVID-19 pandemic have revealed evidence of cardiac involvement and documented that myocardial injury and myocarditis are predictors of poor outcomes. Nonetheless, little is understood regarding SARS-CoV-2 tropism within the heart and whether cardiac complications result directly from myocardial infection. Here, we develop a human engineered heart tissue model and demonstrate that SARS-CoV-2 selectively infects cardiomyocytes. Viral infection is dependent on expression of angiotensin-I converting enzyme 2 (ACE2) and endosomal cysteine proteases, suggesting an endosomal mechanism of cell entry. After infection with SARS-CoV-2, engineered tissues display typical features of myocarditis, including cardiomyocyte cell death, impaired cardiac contractility, and innate immune cell activation. Consistent with these findings, autopsy tissue obtained from individuals with COVID-19 myocarditis demonstrated cardiomyocyte infection, cell death, and macrophage-predominate immune cell infiltrate. These findings establish human cardiomyocyte tropism for SARS-CoV-2 and provide an experimental platform for interrogating and mitigating cardiac complications of COVID-19.