Global m6A RNA Methylation in SARS-CoV-2 Positive Nasopharyngeal Samples in a Mexican Population: A First Approximation Study

Emerging role of N6-methyladenosine RNA modification in regulation of SARS-CoV-2 infection and virus-host interactions

Since December 2019, the infection caused by Severe Acute Respiratory Syndrome Coronavirus Type 2 (SARS-CoV-2) has posed an enormous threat to human health security worldwide. Constant mutation of viral genome and varying therapeutic responses of patients infected with this virus prompted efforts to uncover more novel regulators in the pathogenesis. The involvement of N6-methyladenosine, a modified form of RNA, plays a crucial role in viral replication, viral pathogenicity, and intricate signaling pathways connected with immune responses. This review discusses research advances revealing the regulation of the life cycle of SARS-CoV-2 and antiviral responses of host cells by RNA m6A modification, highlights the biological functions of N6-methyladenosine components in SARS-CoV-2 infection and virus-host interactions, and outlines current challenges and future directions for exploring the potential clinical value of m6A modification in COVID-19.

Targeting G9a translational mechanism of SARS-CoV-2 pathogenesis for multifaceted therapeutics of COVID-19 and its sequalae

By largely unknown mechanism(s), SARS-CoV-2 hijacks the host translation apparatus to promote COVID-19 pathogenesis. We report that the histone methyltransferase G9a noncanonically regulates viral hijacking of the translation machinery to bring about COVID-19 symptoms of hyperinflammation, lymphopenia, and blood coagulation. Chemoproteomic analysis of COVID-19 patient peripheral mononuclear blood cells (PBMC) identified enhanced interactions between SARS-CoV-2-upregulated G9a and distinct translation regulators, particularly the N 6 -methyladenosine (m 6 A) RNA methylase METTL3. These interactions with translation regulators implicated G9a in translational regulation of COVID-19. Inhibition of G9a activity suppressed SARS-CoV-2 replication in human alveolar epithelial cells. Accordingly, multi-omics analysis of the same alveolar cells identified SARS-CoV-2-induced changes at the transcriptional, m 6 A-epitranscriptional, translational, and post-translational (phosphorylation or secretion) levels that were reversed by inhibitor treatment. As suggested by the aforesaid chemoproteomic analysis, these multi-omics-correlated changes revealed a G9a-regulated translational mechanism of COVID-19 pathogenesis in which G9a directs translation of viral and host proteins associated with SARS-CoV-2 replication and with dysregulation of host response. Comparison of proteomic analyses of G9a inhibitor-treated, SARS-CoV-2 infected cells, or ex vivo culture of patient PBMCs, with COVID-19 patient data revealed that G9a inhibition reversed the patient proteomic landscape that correlated with COVID-19 pathology/symptoms. These data also indicated that the G9a-regulated, inhibitor-reversed, translational mechanism outperformed G9a-transcriptional suppression to ultimately determine COVID-19 pathogenesis and to define the inhibitor action, from which biomarkers of serve symptom vulnerability were mechanistically derived. This cell line-to-patient conservation of G9a-translated, COVID-19 proteome suggests that G9a inhibitors can be used to treat patients with COVID-19, particularly patients with long-lasting COVID-19 sequelae.

N6-methyladenosine modification-a key player in viral infection

N6-methyladenosine (m6A) modification is a dynamic, reversible process and is the most prevalent internal modification of RNA. This modification is regulated by three protein groups: methyltransferases ("writers"), demethylases ("erasers"), and m6A-binding proteins ("readers"). m6A modification and related enzymes could represent an optimal strategy to deepen the epigenetic mechanism. Numerous reports have suggested that aberrant modifications of m6A lead to aberrant expression of important viral genes. Here, we review the role of m6A modifications in viral replication and virus-host interactions. In particular, we focus on DNA and RNA viruses associated with human diseases, such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), human immunodeficiency virus (HIV)-1, Epstein-Barr virus (EBV), and Kaposi's sarcoma-associated herpesvirus (KSHV). These findings will contribute to the understanding of the mechanisms of virus-host interactions and the design of future therapeutic targets for treatment of tumors associated with viral infections.

The Use of Epigenetic Biomarkers as Diagnostic and Therapeutic Options

The last few decades have brought tremendous advances in the mechanisms of epigenetic regulation, with DNA methylation, histone methylation and acetylation, microRNAs and other noncoding RNAs being among the most prominent [...]