MicroRNAs (miRNAs) are small non-coding single-stranded RNAs of about 22 nucleotides in length that act as post-transcriptional regulators of gene expression. Depending on the complementarity between miRNA and target mRNA, cleavage, destabilization, or translational suppression of mRNA occurs within the RISC (RNA-induced silencing complex). As gene expression regulators, miRNAs are involved in a variety of biological functions. Dysregulation of miRNAs and their target genes contribute to the pathophysiology of many diseases, including autoimmune and inflammatory disorders. MiRNAs are also present extracellularly in their stable form in body fluids. Their incorporation into membrane vesicles or protein complexes with Ago2, HDL, or nucleophosmin 1 protects them against RNases. Cell-free miRNAs can be delivered to another cell in vitro and maintain their functional potential. Therefore, miRNAs can be considered mediators of intercellular communication. The remarkable stability of cell-free miRNAs and their accessibility in body fluid makes them potential diagnostic or prognostic biomarkers and potential therapeutic targets. Here we provide an overview of the potential role of circulating miRNAs as biomarkers of disease activity, therapeutic response, or diagnosis in rheumatic diseases. Many circulating miRNAs reflect their involvement in the pathogenesis, while for plenty, their pathogenetic mechanisms remain to be explored. Several miRNAs described as biomarkers were also shown to be of therapeutic potential, and some miRNAs are already tested in clinical trials.

• Klíčová slova
• Biomarker, Diagnosis, Rheumatic diseases, Therapy, miRNA,
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

In animals and plants, Dicer enzymes collaborate with double-stranded RNA-binding domain (dsRBD) proteins to convert precursor-microRNAs (pre-miRNAs) into miRNA duplexes. We report six cryo-EM structures of Drosophila Dicer-1 that show how Dicer-1 and its partner Loqs‑PB cooperate (1) before binding pre-miRNA, (2) after binding and in a catalytically competent state, (3) after nicking one arm of the pre-miRNA, and (4) following complete dicing and initial product release. Our reconstructions suggest that pre-miRNA binds a rare, open conformation of the Dicer‑1⋅Loqs‑PB heterodimer. The Dicer-1 dsRBD and three Loqs‑PB dsRBDs form a tight belt around the pre-miRNA, distorting the RNA helix to place the scissile phosphodiester bonds in the RNase III active sites. Pre-miRNA cleavage shifts the dsRBDs and partially closes Dicer-1, which may promote product release. Our data suggest a model for how the Dicer‑1⋅Loqs‑PB complex affects a complete cycle of pre-miRNA recognition, stepwise endonuclease cleavage, and product release.

• Klíčová slova
• Dcr-1, Dicer, Dicer-partner proteins, Loqs-PB, Loquacious, RNase III, cryo-EM, dsRBD, isomiR, miRNA, microRNA,
• MeSH
• Drosophila genetika   MeSH
• mikro RNA * genetika   metabolismus   MeSH
• proteiny Drosophily * genetika   metabolismus   MeSH
• proteiny vázající RNA metabolismus   MeSH
• ribonukleasa III genetika   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Research Support, N.I.H., Intramural MeSH
• Názvy látek
• mikro RNA * MeSH
• proteiny Drosophily * MeSH
• proteiny vázající RNA MeSH
• ribonukleasa III MeSH

Canonical RNAi, one of the so-called RNA-silencing mechanisms, is defined as sequence-specific RNA degradation induced by long double-stranded RNA (dsRNA). RNAi occurs in four basic steps: (i) processing of long dsRNA by RNase III Dicer into small interfering RNA (siRNA) duplexes, (ii) loading of one of the siRNA strands on an Argonaute protein possessing endonucleolytic activity, (iii) target recognition through siRNA basepairing, and (iv) cleavage of the target by the Argonaute's endonucleolytic activity. This basic pathway diversified and blended with other RNA silencing pathways employing small RNAs. In some organisms, RNAi is extended by an amplification loop employing an RNA-dependent RNA polymerase, which generates secondary siRNAs from targets of primary siRNAs. Given the high specificity of RNAi and its presence in invertebrates, it offers an opportunity for highly selective pest control. The aim of this text is to provide an introductory overview of key mechanistic aspects of RNA interference for understanding its potential and constraints for its use in pest control.

• Klíčová slova
• RNAi, argonaute, dicer, dsRNA, miRNA, off-targeting,
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

MicroRNAs (miRNAs) are small non-coding RNAs that post-transcriptionally regulate gene expression. Each step of their production and maturation has to be strictly regulated, as any disruption of control mechanisms may lead to cancer. Thus, we have measured the expression of 19 genes involved in miRNAs biogenesis pathway in tumor tissues of 239 colorectal cancer (CRC) patients, 17 CRC patients with liver metastases and 239 adjacent tissues using real-time PCR. Subsequently, the expression of analyzed genes was correlated with the clinical-pathological features as well as with the survival of patients. In total, significant over-expression of all analyzed genes was observed in tumor tissues as well as in liver metastases except for LIN28A/B. Furthermore, it was shown that the deregulated levels of some of the analyzed genes significantly correlate with tumor stage, grade, location, size and lymph node positivity. Finally, high levels of DROSHA and TARBP2 were associated with shorter disease-free survival, while the over-expression of XPO5, TNRC6A and DDX17 was detected in tissues of patients with shorter overall survival and poor prognosis. Our data indicate that changed levels of miRNA biogenesis genes may contribute to origin as well as progression of CRC; thus, these molecules could serve as potential therapeutic targets.

• Klíčová slova
• RT-qPCR, biogenesis, colorectal cancer, disease-free survival, microRNA, overall survival,
• MeSH
• biosyntetické dráhy genetika   MeSH
• dospělí MeSH
• Kaplanův-Meierův odhad MeSH
• karyoferiny genetika   MeSH
• kolorektální nádory genetika   patologie   MeSH
• lidé středního věku MeSH
• lidé MeSH
• mikro RNA genetika   MeSH
• nádory jater genetika   sekundární   MeSH
• prognóza MeSH
• regulace genové exprese u nádorů * MeSH
• ribonukleasa III genetika   MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• DROSHA protein, human MeSH Prohlížeč
• karyoferiny MeSH
• mikro RNA MeSH
• ribonukleasa III MeSH
• XPO5 protein, human MeSH Prohlížeč

Since the placenta is being continuously remodeled during normal placental development, extracellular nucleic acids of both fetal and placental origin, packed into either trophoblast-derived apoptotic bodies or shedding syncytiotrophoblast microparticles, may be detected in maternal circulation during the course of normal gestation. Placental-insufficiency-related pregnancy complications have been shown to be associated with excessive placental trophoblast apoptosis and shedding of placenta debris. Recent advances in the field are reviewed with a focus on the diagnostic potential of particular molecular biomarkers and their eventual implementation in the currently used predictive and diagnostic algorithms for placental-insufficiency-related pregnancy complications.

• MeSH
• biologické markery krev   MeSH
• DNA krev   MeSH
• extracelulární prostor genetika   MeSH
• lidé MeSH
• matky * MeSH
• placentární insuficience krev   diagnóza   genetika   patologie   MeSH
• RNA krev   MeSH
• těhotenství MeSH
• Check Tag
• lidé MeSH
• těhotenství MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• biologické markery MeSH
• DNA MeSH
• RNA MeSH

To date, at least 900 different microRNA (miRNA) genes have been discovered in the human genome. These short, single-stranded RNA molecules originate from larger precursor molecules that fold to produce hairpin structures, which are subsequently processed by ribonucleases Drosha/Pasha and Dicer to form mature miRNAs. MiRNAs play role in the posttranscriptional regulation of about one third of human genes, mainly via degradation of target mRNAs. Whereas the target mRNAs are often involved in the regulation of diverse physiological processes ranging from developmental timing to apoptosis, miRNAs have a strong potential to regulate fundamental biological processes also in the lung compartment. However, the knowledge of the role of miRNAs in physiological and pathological conditions in the lung is still limited. This review, therefore, summarizes current knowledge of the mechanism, function of miRNAs and their contribution to lung development and homeostasis. Besides the involvement of miRNAs in pulmonary physiological conditions, there is evidence that abnormal miRNA expression may lead to pathological processes and development of various pulmonary diseases. Next, the review describes current state-of-art on the miRNA expression profiles in smoking-related diseases including lung cancerogenesis, in immune system mediated pulmonary diseases and fibrotic processes in the lung. From the current research it is evident that miRNAs may play role in the posttranscriptional regulation of key genes in human pulmonary diseases. Further studies are, therefore, necessary to explore miRNA expression profiles and their association with target mRNAs in human pulmonary diseases.

• MeSH
• genový targeting * MeSH
• lidé MeSH
• mikro RNA genetika   metabolismus   MeSH
• plíce metabolismus   MeSH
• plicní nemoci patofyziologie   MeSH
• regulace genové exprese * MeSH
• zánět patofyziologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• mikro RNA MeSH