microRNAs (miRNAs) are small, non-coding RNA molecules with a length of about 18 to 25 nucleotides. They play a crucial role in gene regulation (epigenetics) by inhibiting the translation of messenger RNA (mRNA) or promoting its degradation. In this way, they influence numerous cellular processes, including cell growth, differentiation, apoptosis, and development.
Biosynthesis of microRNAs
The biosynthesis of miRNAs occurs in several steps:
- Transcription: miRNAs are first transcribed as primary miRNA (pri-miRNA) by RNA polymerase II or III.
- Processing in the cell nucleus The enzyme Drosha cleaves the pri-miRNA into a precursor miRNA (pre-miRNA) approximately 70 nucleotides long./li>
- Transport to the cytoplasm: The pre-miRNA is transported to the cytoplasm by exportin-5.
- Maturation in the cytoplasm: The enzyme Dicer processes the pre-miRNA into a double-stranded miRNA duplex approximately 22 nucleotides long..
- Integration into the RISC complex: One of the two strands is integrated into the RNA-induced silencing complex (RISC) as the guide strand, while the other strand is degraded.
- Gene regulation: The mature miRNA binds to complementary sequences of the target mRNA to inhibit its translation or initiate its degradation.
Functions and significance
miRNAs are involved in many biological processes, including:
- Development and differentiation: They regulate cell line specialization and organ development.
- Disease processes: miRNAs are associated with cancer, neurodegenerative diseases, cardiovascular diseases, and other pathologies.
- Immune response: They modulate inflammatory responses and the immune system.
Applications in conventional, holistic medicine, and research
- Biomarkers: miRNAs can serve as diagnostic markers for cancer, neurodegenerative diseases, or infections.
- Therapeutic approaches: miRNA mimetics (enhancement of miRNA function) and antagomiRs (inhibition of miRNA function) are being investigated as potential therapeutic approaches.
- Genomic editing: The targeted manipulation of miRNAs may enable future personalized medicine and intervention.
References
- Bartel, D. P. (2004). “MicroRNAs: Genomics, Biogenesis, Mechanism, and Function.” Cell, 116(2), 281-297.
- Ambros, V. (2001). “MicroRNAs: Tiny Regulators with Great Potential.” Cell, 107(7), 823-826.
- Krol, J., Loedige, I., & Filipowicz, W. (2010). “The widespread regulation of microRNA biogenesis, function and decay.” Nature Reviews Genetics, 11(9), 597-610.
MicroRNAs are therefore essential regulators of biological processes with great potential for lifestyle, medicine, and biotechnology.
In 2024, the Nobel Prize in Medicine was awarded to US researchers Victor Ambros and Gary Ruvkun. They were honored for their discovery of microRNA and its role in gene regulation. These small RNA molecules are crucial for controlling gene activity and influence numerous biological processes. MicroRNAs are considered THE newly discovered biomarkers that exert a causal influence on our organism.
Victor Ambros is a professor of molecular medicine at the University of Massachusetts Medical School, while Gary Ruvkun is a professor at Harvard Medical School.
https://www.nobelprize.org/prizes/medicine/2024/press-release/
Studies suggest that phytonutrients can modulate the expression of miRNAs. This means that they can influence the activity of miRNAs and thereby alter gene expression.
This mechanism could explain how phytonutrients exert their health-promoting effects. For example, certain phytonutrients have been shown to influence the expression of miRNAs involved in cancer development, inflammation, and metabolic regulation. One study examines the microRNA-mediated health-promoting effects of phytonutrients. The study demonstrates that phytonutrients can regulate the expression of various microRNAs.
MicroRNAs are involved in a variety of cellular processes, such as development, proliferation, differentiation, and apoptosis. Phytonutrients regulate gene expression by binding to target mRNAs, which usually leads to the degradation or translational repression of the target mRNA.
References:
https://ethz.ch/de/news-und-veranstaltungen/eth-news/news/2022/10/wie-die-genetik-ausserhalb-von-genen-unser-koerpergewicht-beeinflusst.html
https://www.ots.at/presseaussendung/OTS_20190828_OTS0105/nussmolekuele-koennen-das-entzuendungs-und-stoffwechselprofil-von-fettzellen-guenstig-beeinflussen?utm_source=chatgpt.com
https://www.mpg.de/8973715/mpip_jb_2014
https://dzhk.de/newsroom/aktuelles/news/artikel/erste-microrna-therapie-fuer-das-herz-funktioniert-beim-menschen/
https://link.springer.com/article/10.1007/s40664-024-00555-y