Genotoxicity and hypomethylation of LINE-1 induced by electronic cigarettes.

Currently, the marketing of electronic cigarettes as a safe alternative to smoking has increased, which is associated with greater use of these devices, especially among young people and smokers interested in quitting tobacco cigarettes. Given the growing use of this type of product, there is a need to determine the consequences of electronic cigarettes on human health, especially since many of the compounds contained in the aerosol and liquid of these devices have a high potential to be carcinogenic and genotoxic. Additionally, many of these compounds' aerosol concentrations exceed the safe limits. We have evaluated the levels of genotoxicity and changes in DNA methylation patterns associated with vaping. We analyzed a total of 90 peripheral blood samples from a population of vapers (n = 32), smokers (n = 18), and controls (n = 32), in which the frequencies of genotoxicity were determined by the cytokinesis-blocking micronuclei (CBMN) assay and the patterns of methylation of the repetitive elements of LINE-1 through the Quantitative Methylation Specific PCR (qMSP) assay. Here we show an increase in genotoxicity levels associated with vaping habits. Additionally, the group of vapers showed changes at the epigenetic level specifically associated with the loss of methylation of the LINE-1 elements. These changes in LINE-1 methylation patterns were reflected in its representative RNA expression detected in vapers.

Epigenetic mechanisms and host factors impact ACE2 gene expression: Implications in COVID-19 susceptibility.

BACKGROUND: The ACE2 protein acts as a gateway for SARS-CoV-2 in the host cell, playing an essential role in susceptibility to infection by this virus. Genetics and epigenetic mechanisms related to the ACE2 gene are associated with changes in its expression and, therefore, linked to increased susceptibility to infection. Although some variables such as sex, age, and obesity have been described as risk factors for COVID-19, the molecular causes involved in the disease susceptibility are still unknown. AIM: To evaluate the ACE2 gene expression profiles and their association with epigenetic mechanisms and demographic or clinical variables. METHODS: In 500 adult volunteers, the mRNA expression levels of the ACE2 gene in nasopharyngeal swab samples and its methylation status in peripheral blood samples were quantified by RT-qPCR and qMSP, respectively. The existence of significant differences in the ACE2 gene expression and its determinants were evaluated in different study groups according to several demographic or clinical variables such as sex, age, body mass index (BMI), smoking, SARS-CoV-2 infection, and presence of underlying diseases such as type II diabetes mellitus (DM2), asthma and arterial hypertension (AHT). RESULTS: Our results show that ACE2 gene overexpression, directly involved in susceptibility to SARS-CoV-2 infection, depends on multiple host factors such as male sex, age over 30 years, smoking, the presence of obesity, and DM2. Likewise, it was determined that the ACE2 gene expression is regulated by changes in the DNA methylation patterns in its promoter region. CONCLUSIONS: The ACE2 gene expression is highly variable, and this variability is related to habits such as smoking and demographic or clinical variables, which details the impact of environmental and host factors on our epigenome and, therefore, in susceptibility to SARS-CoV-2 infection.