Transcriptomic Analysis of HCN-2 Cells Suggests Connection among Oxidative Stress, Senescence, and Neuron Death after SARS-CoV-2 Infection.

Andrea Valeri,Mara Biasin,Gloria Pelizzo,Stephana Carelli,Agnese Gugliandolo,Placido Bramanti,Luigi Chiricosta,Gian Vincenzo Zuccotti,Gioia Cappelletti,Valeria Calcaterra,Emanuela Mazzon

doi:10.3390/cells10092189

Abstract

According to the neurological symptoms of SARS-CoV-2 infection, it is known that the nervous system is influenced by the virus. We used pediatric human cerebral cortical cell line HCN-2 as a neuronal model of SARS-CoV-2 infection, and, through transcriptomic analysis, our aim was to evaluate the effect of SARS-CoV-2 in this type of cells. Transcriptome analyses revealed impairment in TXN gene, resulting in deregulation of its antioxidant functions, as well as a decrease in the DNA-repairing mechanism, as indicated by the decrease in KAT5. Western blot analyses of SOD1 and iNOS confirmed the impairment of reduction mechanisms and an increase in oxidative stress. Upregulation of CDKN2A and a decrease in CDK4 and CDK6 point to the blocking of the cell cycle that, according to the deregulation of repairing mechanism, has apoptosis as the outcome. A high level of proapoptotic gene PMAIP1 is indeed coherent with neuronal death, as also supported by increased levels of caspase 3. The upregulation of cell-cycle-blocking genes and apoptosis suggests a sufferance state of neurons after SARS-CoV-2 infection, followed by their inevitable death, which can explain the neurological symptoms reported. Further analyses are required to deeply explain the mechanisms and find potential treatments to protect neurons from oxidative stress and prevent their death.

Highlights

Cell cultures were incubated with 1 multiplicity of infection (MOI); the incubator was set at 37 ◦ C and 5%
The replication rate increased over time, as is clear from N1 and N2 copy numbers at day 3 and day 6, when the cells were harvested for further analyses
We found that the expressions of TXN and SOD1 were reduced

Summary

Introduction

Coronavirus is a family of RNA viruses, which infect both mammals and birds. Their one-stranded RNA filament is surrounded by a nucleoprotein, giving the typical appearance of the tubular helix coiled inside the lipid-containing bilayer shell [1]. The name of the family came from membrane observation, where the presence of some clublike spikes recalls a crown [2]. SARS-CoV-2 has the potential to cause life-threatening illness, primarily in the respiratory tract. The European Center of Disease Prevention and Controls states that the five most common symptoms of SARS-CoV-2 are fever, shortness of breath, cough, fatigue/malaise, and confusion [3]. With the pandemic still ongoing, the long-term consequences of the disease are not yet fully elucidated

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