Genes Involved in miRNA Biogenesis Are Not Downregulated in SARS-CoV-2 Infection.

Area of Science:

• Molecular Biology
• Virology
• Genetics

Background:

• MicroRNAs (miRNAs) are small non-coding RNAs crucial for gene regulation and implicated in viral infections.
• Viral infections can disrupt miRNA pathways by inhibiting genes involved in miRNA biogenesis.
• Previous observations suggested reduced miRNA levels in severe COVID-19, hinting at their potential as biomarkers.

Purpose of the Study:

• To investigate the impact of SARS-CoV-2 infection on the messenger RNA (mRNA) expression levels of key miRNA biogenesis genes.
• To determine if SARS-CoV-2 influences genes such as AGO2, DICER1, DGCR8, DROSHA, and XPO5.

Main Methods:

• Quantitative reverse-transcription polymerase chain reaction (RT-qPCR) was used to measure mRNA levels.
• Specimens included nasopharyngeal swabs from COVID-19 patients (severe and non-severe) and controls.
• In vitro experiments involved SARS-CoV-2 infection of NHBE, Calu-3, and Vero E6 cells.

Main Results:

• No significant differences in mRNA levels of AGO2, DICER1, DGCR8, DROSHA, and XPO5 were found between severe COVID-19 patients, non-severe cases, and controls.
• SARS-CoV-2 infection did not significantly alter the expression of these genes in NHBE and Calu-3 cells.
• A slight upregulation of AGO2, DICER1, DGCR8, and XPO5 mRNA was observed in Vero E6 cells 24 hours post-infection.

Conclusions:

• The study found no evidence of mRNA downregulation for key miRNA biogenesis genes during SARS-CoV-2 infection in patient samples or most cell lines.
• These findings suggest that SARS-CoV-2 does not broadly inhibit miRNA biogenesis at the mRNA level of these specific genes.
• The observed minor upregulation in Vero E6 cells warrants further investigation but does not support a general inhibitory mechanism on miRNA biogenesis genes by SARS-CoV-2.