Stability of SARS-CoV-2-Encoded Proteins and Their Antibody Levels Correlate with Interleukin 6 in COVID-19 Patients

SARS-CoV-2 Accessory Protein Orf7b Induces Lung Injury via c-Myc Mediated Apoptosis and Ferroptosis

The pandemic of coronavirus disease 2019 (COVID-19) has been the foremost modern global public health challenge. The airway is the primary target in severe acute respiratory distress syndrome coronavirus 2 (SARS-CoV-2) infection, with substantial cell death and lung injury being signature hallmarks of exposure. The viral factors that contribute to cell death and lung injury remain incompletely understood. Thus, this study investigated the role of open reading frame 7b (Orf7b), an accessory protein of the virus, in causing lung injury. In screening viral proteins, we identified Orf7b as one of the major viral factors that mediates lung epithelial cell death. Overexpression of Orf7b leads to apoptosis and ferroptosis in lung epithelial cells, and inhibitors of apoptosis and ferroptosis ablate Orf7b-induced cell death. Orf7b upregulates the transcription regulator, c-Myc, which is integral in the activation of lung cell death pathways. Depletion of c-Myc alleviates both apoptotic and ferroptotic cell deaths and lung injury in mouse models. Our study suggests a major role of Orf7b in the cell death and lung injury attributable to COVID-19 exposure, supporting it as a potential therapeutic target.

Biodistribution of RNA Vaccines and of Their Products: Evidence from Human and Animal Studies

Explosive developments in mRNA vaccine technology in the last decade have made it possible to achieve great success in clinical trials of mRNA vaccines to prevent infectious diseases and develop cancer treatments and mRNA-based gene therapy products. The approval of the mRNA-1273 and BNT162b2 mRNA vaccines against SARS-CoV-2 by the U.S. Food and Drug Administration has led to mass vaccination (with mRNA vaccines) of several hundred million people around the world, including children. Despite its effectiveness in the fight against COVID-19, rare adverse effects of the vaccination have been shown in some studies, including vascular microcirculation disorders and autoimmune and allergic reactions. The biodistribution of mRNA vaccines remains one of the most poorly investigated topics. This mini-review discussed the results of recent experimental studies on humans and rodents regarding the biodistribution of mRNA vaccines, their constituents (mRNA and lipid nanoparticles), and their encoded antigens. We focused on the dynamics of the biodistribution of mRNA vaccine products and on the possibility of crossing the blood-brain and blood-placental barriers as well as transmission to infants through breast milk. In addition, we critically assessed the strengths and weaknesses of the detection methods that have been applied in these articles, whose results' reliability is becoming a subject of debate.

Evaluation of Broad Anti-Coronavirus Activity of Autophagy-Related Compounds Using Human Airway Organoids

To deal with the broad spectrum of coronaviruses, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), that threaten human health, it is essential to not only drugs develop that target viral proteins but also consider drugs that target host proteins/cellular processes to protect them from being hijacked for viral infection and replication. To this end, it has been reported that autophagy is deeply involved in coronavirus infection. In this study, we used airway organoids to screen a chemical library of autophagic modulators to identify compounds that could potentially be used to fight against infections by a broad range of coronaviruses. Among the 80 autophagy-related compounds tested, cycloheximide and thapsigargin reduced SARS-CoV-2 infection efficiency in a dose-dependent manner. Cycloheximide treatment reduced the infection efficiency of not only six SARS-CoV-2 variants but also human coronavirus (HCoV)-229E and HCoV-OC43. Cycloheximide treatment also reversed viral infection-induced innate immune responses. However, even low-dose (1 μM) cycloheximide treatment altered the expression profile of ribosomal RNAs; thus, side effects such as inhibition of protein synthesis in host cells must be considered. These results suggest that cycloheximide has broad-spectrum anti-coronavirus activity in vitro and warrants further investigation.