Transposable elements are important sources of miRNA, long non-coding RNAs genes,
and their targets in the composition of protein-coding genes in plants and animals. Therefore, the
detection of expression levels of specific non-coding RNAs in various tissues and cells in normal and
pathological conditions may indicate a programmed pattern of transposable elements’ activation.
This reflects the species-specific composition and distribution of transposable elements in genomes,
which underlie gene regulation in every cell division, including during aging. TEs’ expression
is also regulated by epigenetic factors (DNA methylation, histone modifications), SIRT6, cytidine
deaminases APOBEC3, APOBEC1, and other catalytic proteins, such as ERCC, TREX1, RB1, HELLS,
and MEGP2. In evolution, protein-coding genes and their regulatory elements are derived from
transposons. As part of non-coding regions and introns of genes, they are sensors for transcriptional
and post-transcriptional control of expression, using miRNAs and long non-coding RNAs, that arose
from transposable elements in evolution. Methods (Orbld, ncRNAclassifier) and databases have been
created for determining the occurrence of miRNAs from transposable elements in plants (PlanTE-MIR
DB, PlaNC-TE), which can be used to design epigenetic gene networks in ontogenesis. Based on
the data accumulated in the scientific literature, the presence of 467 transposon-derived miRNA
genes in the human genome has been reliably established. It was proposed to create an updated and
controlled online bioinformatics database of miRNAs derived from transposable elements in healthy
individuals, as well as expression changes of these miRNAs during aging and various diseases, such
as cancer and difficult-to-treat diseases. The use of the information obtained can open new horizons
in the management of tissue and organ differentiation to aging slow down. In addition, the created
database could become the basis for clarifying the mechanisms of pathogenesis of various diseases
(imbalance in the activity of transposable elements, reflected in changes in the expression of miRNAs)
and designing their targeted therapy using specific miRNAs as targets. This article provides examples
of the detection of transposable elements-derived miRNAs involved in the development of specific
malignant neoplasms, aging, and idiopathic pulmonary fibrosis.