Transposons Acting as Competitive Endogenous RNAs: In-Silico Evidence from Datasets Characterised by L1 Overexpression

Abstract

LINE L1 are transposable elements that can replicate within the genome by passing through RNA intermediates. The vast majority of these element copies in the human genome are inactive and just between 100 and 150 copies are still able to mobilize. During evolution, they could have been positively selected for beneficial cellular functions. Nonetheless, L1 deregulation can be detrimental to the cell, causing diseases such as cancer. The activity of miRNAs represents a fundamental mechanism for controlling transcript levels in somatic cells. These are a class of small non-coding RNAs that cause degradation or translational inhibition of their target transcripts. Beyond this, competitive endogenous RNAs (ceRNAs), mostly made by circular and non-coding RNAs, have been seen to compete for the binding of the same set of miRNAs targeting protein coding genes. In this study, we have investigated whether autonomously transcribed L1s may act as ceRNAs by analyzing public dataset in-silico. We observed that genes sharing miRNA target sites with L1 have a tendency to be upregulated when L1 are overexpressed, suggesting the possibility that L1 might act as ceRNAs. This finding will help in the interpretation of transcriptomic responses in contexts characterized by the specific activation of transposons.

The Long Covid-19 Syndrome the Spike Protein and Stem Cells, the Underrated Role of Retrotransposons, a Working Hypothesis

“…It should be added that the reduction in pericyte vascular coverage observed in the heart or lungs of patients with COVID-19 indicated that SARS-CoV-2 may affect the microvasculature by targeting pericytes. It has been noted that an increase in adverse cardiovascular events, which often affect young and athletic people as we mentioned earlier, could be an event due to either the greater accumulation of Ang II or to the higher level of active circulating SCs much more present in younger individuals and those who practice sport [96][97][98][99][100].…”

“…The inflammatory process can spread up to the fiber tracts located in the dorsal roots reaching the ganglion neurons that from there tend to influence neurons in the spinal cord, reaching the sympathetic efferent neurons. The direct involvement of stem cells is therefore assumed, derived infected mature and progenitor neuro cells may also contribute to the disorders of sympathetic afferent neurons that are associated with multiple districts such as heart, esophagus and bronchi through: i), the affection of vagal afferent axons that are associated with myocardial receptors, which ascend in the vagal nerves up to the node ganglion reaching the nucleus of the tractus solitarius and interneurons; and, ii) these interneurons will in turn affect the vagus and sympathetic preganglionic efferent nerves in the bulbospinal tracts [97][98][99][100].…”

“…We assume that probably the final stage of stem cell differentiation does not express particular modified morphologies, or particular patterns of gene expression and epigenetic modifications that often go undetected. However, the role of the L1 retrotransposon mechanism in the life cycle of affected SCs carrying the viral mRNA may be accounted for those abnormal features that are not shown using conventional detection tests [100,101].…”

miRNAs: From Master Regulators of Gene Expression to Biomarkers Involved in Intercellular Communication

“…The paper by Esposito et al [28] studied a possible new function of transposons (TEs), which are mobile genetic elements that can move around the genome and sometimes affect the expression of nearby genes. TEs, depending on where they jump, can insert functional domains such as miRNA binding sites transforming transcripts in miRNA sponges (see reference in the paper).…”

Retroviral Insertion Polymorphism (RIP) of Porcine Endogenous Retroviruses (PERVs) in Pig Genomes

“…ERVs can modulate gene expression, contribute to genetic variation and drive evolution. They have also been co-opted by the host for beneficial roles in some instances [21,22].…”