Viral and Host Genetic and Epigenetic Biomarkers Related to SARS-CoV-2 Cell Entry, Infection Rate, and Disease Severity

SIMPLE SUMMARY: COVID-19 emerged as a new disease with quick transmission and a high mortality rate at the end of 2019, caused by SARS-CoV-2. Common features of the coronavirus family helped resolve structural and entry mechanism characteristics of SARS-CoV-2. Still, rapid mutagenesis leads to the fast evolution of the virus and the emergence of new strains that differ in infectivity, morbidity, and mortality. Besides differences in the viral genome, genetic variability in the host defense and immune systems may also play a role in the outcome of virus–host interactions. Furthermore, epigenetic mechanisms may also influence the outcomes, including miRNA gene silencing and DNA methylation, which may be heavily influenced by SARS-CoV-2. Molecular biomarkers are intensively investigated as potential predictive and prognostic biomarkers of the disease course and treatment response. We reviewed new data regarding the mechanisms behind fast virus mutagenesis, infectivity, and potential human genetic and epigenetic characteristics that may lead to a more severe or lethal outcome of the disease. ABSTRACT: The rapid spread of COVID-19 outbreak lead to a global pandemic declared in March 2020. The common features of corona virus family helped to resolve structural characteristics and entry mechanism of SARS-CoV-2. However, rapid mutagenesis leads to the emergence of new strains that may have different reproduction rates or infectivity and may impact the course and severity of the disease. Host related factors may also play a role in the susceptibility for infection as well as the severity and outcomes of the COVID-19. We have performed a literature and database search to summarize potential viral and host-related genomic and epigenomic biomarkers, such as genetic variability, miRNA, and DNA methylation in the molecular pathway of SARS-CoV-2 entry into the host cell, that may be related to COVID-19 susceptibility and severity. Bioinformatics tools may help to predict the effect of mutations in the spike protein on the binding to the ACE2 receptor and the infectivity of the strain. SARS-CoV-2 may also target several transcription factors and tumour suppressor genes, thus influencing the expression of different host genes and affecting cell signalling. In addition, the virus may interfere with RNA expression in host cells by exploiting endogenous miRNA and its viral RNA. Our analysis showed that numerous human miRNA may form duplexes with different coding and non-coding regions of viral RNA. Polymorphisms in human genes responsible for viral entry and replication, as well as in molecular damage response and inflammatory pathways may also contribute to disease prognosis and outcome. Gene ontology analysis shows that proteins encoded by such polymorphic genes are highly interconnected in regulation of defense response. Thus, virus and host related genetic and epigenetic biomarkers may help to predict the course of the disease and the response to treatment.