how to use microrna as treatment

by Mr. Gay Corwin Sr. Published 3 years ago Updated 3 years ago

One way to therapeutically mimic or reexpress a miRNA is by using synthetic RNA duplexes designed to mimic the endogenous functions of the miRNA of interest, with modifications for stability and cellular uptake.

Full Answer

How does microRNA work in cancer treatment?

The microRNA combination used in this study appears to work by interfering with cancer cells’ ability to grow and to stick to other cells, the researchers found. “This is a great proof of principle,” says Mauro Ferrari, the president and CEO of the Houston Methodist Research Institute, who was not involved in the study.

How are microRNAs transcribed?

In the canonical pathway, microRNA are transcribed as long primary miRNA transcripts (pri-miRNAs) by RNA polymerase II (and occasionally RNA polymerase III). Pri-miRNAs can be several kilobases long and can contain the stem loops of several mature miRNAs (giving rise to miRNA clusters—see Box 1 ).

What are the clinical applications of miRNAs?

Clinical applications of miRNAs are on the horizon. The novel anti-miRNA treatment miravirsen is already in phase 2b trials suggesting miRNA-based treatments may well become a reality; viral vaccines attenuated through incorporation of miRNA target sequences are at the preclinical stage; and miRNA biomarkers of infection hold promise.

Are microRNAs therapeutic entities?

With the discovery of microRNAs (miRNAs) being powerful regulators in a wide variety of diseases, it is only a logical consequence that the possibilities of viewing miRNAs as therapeutic entities are being explored.

How is miRNA used?

The miRNA functions as a guide by base-pairing with target mRNA to negatively regulate its expression. The level of complementarity between the guide and mRNA target determines which silencing mechanism will be employed; cleavage of target messenger RNA (mRNA) with subsequent degradation or translation inhibition Fig.

What is microRNA therapy?

MicroRNA (miRNA)-based therapeutics can be divided into miRNA mimics and inhibitors of miRNAs (also known as antimiRs). miRNA mimics are synthetic double-stranded small RNA molecules that match the corresponding miRNA sequence and therefore functionally aim to replenish the lost miRNA expression in diseases.

How do microRNAs cause cancer?

MiRNAs may function as either oncogenes or tumor suppressors under certain conditions. The dysregulated miRNAs have been shown to affect the hallmarks of cancer, including sustaining proliferative signaling, evading growth suppressors, resisting cell death, activating invasion and metastasis, and inducing angiogenesis.

How are miRNA delivered?

Lipid-based nanocarriers Many studies have validated the use of cationic liposomes as carriers for transporting miRNA in vivo. At present, a large number of cationic lipids have been synthesized for nucleic acid drug delivery; however, low delivery efficiency is the main obstacle that limits their clinical application.

What is miRNA replacement therapy?

By restoring the expression of tumor suppressive miRNAs, miRNA replacement therapy seeks to reinstate those cellular programs that are active in normal cells and interfere with oncogenic programs necessary for the malignant phenotype.

How does miRNA help block gene expression?

How does miRNA function to help block gene expression? The miRNA pieces attach to a cluster of proteins to form silencing complex. The silencing complex binds to and destroys any mRNA containing a sequence that is complementary to the miRNA.

Why are miRNAs important?

miRNAs have key roles in the regulation of distinct processes in mammals. They provide a key and powerful tool in gene regulation and thus a potential novel class of therapeutic targets. miRNAs play an evolutionarily conserved developmental role and diverse physiological functions in animal.

Where is microRNA found?

While the majority of miRNAs are located within the cell, some miRNAs, commonly known as circulating miRNAs or extracellular miRNAs, have also been found in extracellular environment, including various biological fluids and cell culture media.

Is microRNA an epigenetic?

miRNAs, as epigenetic modulators, affect the protein levels of the target mRNAs without modifying the gene sequences. Moreover, miRNAs can also be regulated by epigenetic modifications, including DNA methylation, RNA modification, and histone modifications.

How do you detect microRNAs?

Traditional methods for detection of miRNAs include Northern blotting, quantitative reverse transcription polymerase chain reaction (qRT-PCR), next-generation sequencing, and microarray-based hybridization (5, 8, 9).

What is the difference between miRNA and mRNA?

Therefore, a miRNA regulates many mRNAs, and conversely, a mRNA is regulated by several miRNAs. Correspondence between miRNAs and mRNAs for regulation or non-regulation is not one-to-one: there is a complex correspondence, "many-to-many."

What is the first step in the production of a miRNA?

production of miRNAs -5 steps. 1- initially transcribed into longer molecules called primary miRNAs which fold into hairpin loops. 2- looped pri-miRNas converted into mature miRNAs. 3-drosha then cleaves pre-mirnas into hairpins called precursor RNAs (pre-miRNAs)

What is microRNA and how does it work?

microRNA is the name of a family of molecules that helps cells control the kinds and amounts of proteins they make. That is, cells use microRNA to help control gene expression. Molecules of microRNA are found in cells and in the bloodstream.

Is microRNA gene therapy?

Combining miRNA regulation with gene therapy allows targeted and potent expression of transgenes. Such 'de-targeting' strategies incorporate miRNA target sites in the 3′ UTR of the therapeutic transgene, preventing its expression in cells that express the corresponding miRNA.

Where are miRNAs found?

Mature miRNAs localize in multiple subcellular locations in the cytoplasm, such as RNA granules, endomembranes, and mitochondria, and secrete outside cells via exosomes. Recent studies have revealed that mature miRNAs can also localize to the nucleus, where they could function in epigenetic regulation.

What is the difference between mRNA and miRNA?

What is microRNA?

Learn more about microRNA -- the name of a family of molecules that helps cells control the kinds and amounts of proteins they make. Learn more about microRNA -- the name of a family of molecules that helps cells control the kinds and amounts of proteins they make. You must have javascript enabled to use this website.

What is the role of microRNA in the cell?

That is, cells use microRNA to help control gene expression . Molecules of microRNA are found in cells and in the bloodstream. (Note: microRNA is abbreviated “miRNA,” but here we will use “microRNA” throughout.)

What is the role of microRNAs in cellular processes?

MicroRNAs (miRNAs) provide new therapeutic targets for many diseases, while their myriad roles in development and cellular processes make them fascinating to study. We still do not fully understand the molecular mechanisms by which miRNAs regulate gene expression nor do we know the complete repertoire of mRNAs each miRNA regulates.

How are miRNAs transcribed?

miRNAs are transcribed from their own genes by RNA polymerase II. Consequently, miRNA primary transcripts (pri-miRNAs) begin with 5′-7-methylguanosine caps and end with 3′ poly (A) tails. The pre-miRNA, a ∼ 65 nucleotide stem–loop structure that contains the miRNA and its corresponding miRNA * within its stem, resides within the pri-miRNA ( Figure 1 ). Cleavage of the pri-miRNA by the RNase III enzyme, Drosha, releases the pre-miRNA stem-loop, which bears the two nucleotide, 3′ overhanging ends characteristic of RNase III enzymes. The pre-miRNA is then exported to the cytoplasm, where its loop is removed by a second RNase III enzyme, Dicer, that specifically recognizes the pre-miRNA structure, including its two nucleotide, 3′ overhanging end. The resulting miRNA/miRNA * duplex is then loaded into a member of the Argonaute family of proteins. Subsequently, the miRNA * strand departs from the Argonaute protein, producing a mature, active miRNA:protein complex.

What is the role of miRNA in obesity?

Inappropriate miRNA expression has been linked to a variety of diseases. 3, 4 For example, the let -7 miRNA prevents proliferation of cancer stem cells. miRNAs have roles in metabolic diseases such as obesity and diabetes; differentiation of adipocytes is promoted by miR-143, and insulin secretion is regulated by miR-375 in pancreatic-islet cells.

How many miRNAs are there in the human genome?

The human genome contains more than 500 miRNAs, and each miRNA can repress hundreds of genes, regulating almost every cellular process. 1, 2 Individual miRNAs are often produced only in specific cell types or developmental stages.

How many base pairs does a miRNA have?

However, human miRNAs generally base pair only partially with their target mRNAs. In fact, as few as six base pairs between a special region of the miRNA, the ‘seed sequence’ (miRNA nucleotides 2 through 7 or 8), and an mRNA may suffice to recruit Argonaute to repress the mRNA ( Figure 2 ).

What is the binding of a miRNA to an mRNA?

Binding of a miRNA:Argonaute protein complex to the 3′ untranslated region (UTR) of an mRNA silences its expression. 1 The human genome encodes four closely related Argonaute proteins, Ago1, Ago2, Ago3 and Ago4, and most tissues and cultured mammalian cell lines express all four, although in different proportions.

Where do miRNAs bind?

Typical miRNA-binding sites also feature an adenosine (underlined) across from the first nucleotide of the miRNA , even though the structure of a miRNA bound to an Argonaute protein precludes base pairing at this position. Full size image.

What is the role of miRNAs in the human body?

They play an important role in gene regulation through binding toa specific region in open reading frames (ORFs) and/or untranslated regions (UTRs) to block the translation processes through either degrading or blocking mRNA resulting in knocking down or suppression of targeted genes. Plants and many organisms protect themselves from viruses through the production of miRNAs, which are complementary to 3UTR of viruses resulting in degrading the viral mRNA or block the translation on ribosomes. As pandemic, COVID-19, and its consequences on the global economy, we hypothesized a new approach for the treatment of COVID-19 paints. This approach includes designing a mix of miRNAs targeting several regions on COVID-19 open reading frame (ORF) and 3 UTR and suitable delivery system targeting respiratory system tissues. These synthesized miRNAs may be delivered to humansinnon-viral delivery systems such as liposomes like exosome (extracellular vesicle), polymer-based carriers, or inorganic nanoparticles, which are considered to be more suitable for human use.

How do plants protect themselves from viruses?

Plants and many organisms protect themselves from viruses through the production of miRNAs, which are complementary to 3UTR of viruses resulting in degrading the viral mRNA or block the translation on ribosomes. As pandemic, COVID-19, and its consequences on the global economy, we hypothesized a new approach for the treatment of COVID-19 paints.

Can miRNAs be delivered to humans?

These synthesized miRNAs may be delivered to humansinnon-viral delivery systems such as liposomes like exosome (extracellular vesicle), polymer-based carriers, or inorganic nanoparticles, which are considered to be more suitable for human use. Keywords: COVID-19; Treatment; Virus; miRNAs. Copyright © 2020 Elsevier Ltd.

Which miRNAs are upregulated in different settings?

The miR-15 family consists of multiple miRNAs (miR-15a, miR-15b, miR-16–1, miR-16–2, miR-195, and miR-497) and is consistently found to be upregulated in different settings of disease, including cancer and cardiac diseases.

What is the role of miRNA in hepatitis C?

A hepatic-specific miRNA, miR-122, was shown to be of critical importance to the replication of hepatitis C virus (HCV). 11, 12 Sequestration of miR-122 with antisense constructs targeting the miRNA significantly reduced the replication of HCV RNA, suggesting that miR-122 may present a target for antiviral intervention. 12 Only several months after the initial reports on miR-122, Krutzfeldt et al reported on the feasibility of manipulating miRNA levels in vivo, including miR-122 levels, using intravenous administration of a novel class of chemically engineered oligonucleotides, termed “antagomirs.” These chemically modified oligonucleotides are complementary to the mature miRNA sequence and are conjugated to cholesterol to facilitate cellular uptake. These initial experiments validated that systemic delivery through intravenous administration efficiently reduced the miRNA of interest for an extended period of time in multiple tissues in vivo. 13, 14 Subsequent studies using systemic delivery of an unconjugated LNA-containing anti-miR potently antagonized miR-122 in mice and nonhuman primates. 15, 16 Nonclinical studies of up to 13 weeks in 2 species support the development of this anti-miR and a recent preliminary report indicates that the safety profile of this LNA-modified oligonucleotide is remarkably similar to other drugs in this class. There were no apparent hepatic morphological changes associated with inhibition of miR-122 in these studies. The inhibition of miR-122 by this LNA–anti-miR was also shown to be safe and efficacious in chronically infected chimpanzees by suppressing HCV viremia and improving HCV-induced liver pathology. 17 Clinical trials using anti-miR-122 against HCV are currently ongoing (see section Initial Clinical Trials).

How are miRNAs related to miR 107?

MiR-103 and miR-107 are related miRNAs that differ by only 1 base in their 3′ region. Although they are intronically located within the pantothenate kinase (PANK) genes, at least in mice, their expression does not correlate with expression of the host genes. 39 Bioinformatic target prediction programs indicate that these miRNAs can potentially regulate mRNA genes in pathways that involve cellular Acetyl-CoA and lipid levels. 40 Recently, Stoffel et al 41 showed that the expression of miR-103 and miR-107 is upregulated in obese mice and that antagomir-based silencing of miR-103/107 leads to improved glucose homeostasis and insulin sensitivity, whereas gain of miR-103/107 function in either liver or fat is sufficient to induce impaired glucose homeostasis. Target identification analysis indicated caveolin-1, a critical regulator of the insulin receptor, to be a direct target of miR-103/107. The upregulation of caveolin-1 on miR-103/107 inhibition in adipocytes correlates with stabilization of the insulin receptor, enhanced insulin signaling, decreased adipocyte size, and enhanced insulin-stimulated glucose uptake. These findings demonstrate the potential importance of miR-103/107 to insulin sensitivity and identify these miRNAs as potential new targets for the treatment of type 2 diabetes and obesity.

What are the requirements for anti-miR?

The key requirements for an anti-miR are that the chemistry must be cell permeable, cannot be rapidly excreted, must be stable in vivo, and should bind to the miRNA of interest with high specificity and affinity. 6 – 8 Several modifications have been used in vivo thus far.

What is the effect of miR-92a?

Inhibition of miR-92a in vivo with intravenous administration of an antagomir resulted in enhanced blood vessel growth as well as functional improvement of damaged tissue in models of hind limb ischemia and myocardial infarction. 28 The neoangiogenic effect of inhibiting miR-92a in vivo was attributed to the derepression of the multiple proangiogenic factors, including integrin α5, a direct target of miR-92a. The proangiogenic capacity of miR-92a inhibition is currently being explored as a potential therapy in diseases like ischemic heart disease or peripheral artery disease.

What is the role of miR-155 in the immune system?

An important regulator of the immune system is miR-155. Genetic deletion indicated that miR-155 has an important role regulating T helper cell differentiation, at least in part, by regulating cytokine production. 20 Follow-up studies showed that exposure of cultured macrophages and mice to lipopolysaccharide lead to upregulation of miR-155 and that the transcription factor c/ebp β is a direct target of miR-155. Interestingly, expression profiling of lipopolysaccharide-stimulated macrophages combined with overexpression and silencing of miR-155 in murine macrophages and human monocytic cells uncovered marked changes in the expression of granulocyte colony-stimulating factor, a central regulator of granulopoiesis during inflammatory responses. 21 Consistent with these data, silencing of miR-155 in lipopolysaccharide-treated mice by systemically administering a LNA-modified anti-miR resulted in derepression of the c/ebp β isoforms and downregulation of granulocyte colony-stimulating factor expression in mouse splenocytes, which indicates the potential of miR-155 antagonists for the treatment of chronic inflammatory diseases. 21

Is MiR-21 a MAP kinase?

MiR-21 is one of the most dynamically regulated miRNAs in various pathological settings, ranging from cancer to heart disease. Several years ago, Thum et al 22 demonstrated that in vivo knockdown of miR-21 with antagomirs blunted cardiomyocyte hypertrophy, inhibited and reversed interstitial fibrosis, and attenuated cardiac dysfunction after thoracic aortic banding. The ability of antagomirs against miR-21 to regulate cardiac disease was attributed to regulation of MAP kinase signaling pathways in cardiac fibroblasts through the miR-21 target, Spry1, a negative regulator of MAP kinase signaling. Although both genetic deletion of miR-21 and anti–miR-based inhibition of miR-21 failed to result in an overt phenotype at baseline and was incapable of blocking cardiac remodeling during stress in one report, 23 others have shown that genetic deletion or anti-miR based inhibition induces therapeutic relevance in inhibiting fibrosis in different tissues 24 – 26 and in cancer. 27 Although the contradicting results regarding cardiac remodeling remain unexplained, based on the additional anti-miR findings, inhibition of miR-21 is actively being explored for therapeutic applications in both cancer and fibrotic diseases.

Why are microRNAs important?

MicroRNAs are Important Controllers of Leukocyte Development. Evidence that miRNAs are important in the immune system first arose from mice studies showing that the production of mature B and T lymphocytes is altered by manipulating miRNA expression in hematopeotic stem cells and immature lymphyocytes ( 7, 8, 10 ).

What are the roles of microRNAs in host response?

MicroRNAs are essential mediators of host response to pathogens. They have pleiotropic roles which microbes have evolved to exploit. Elucidating the roles miRNAs in host response to infectious disease is inherently interesting at it provides a tool for identifying key genes and pathways that must be activated, enhanced, repressed, or silenced to facilitate an effective immune response. The complex regulatory network within which miRNAs are embedded, make unpicking the roles of miRNAs tough but not impossible. Integrating large miRNA and mRNA datasets using advanced statistical techniques (in a “systems biology” approach) will facilitate the unpicking of these complex networks.

How do miRNAs inhibit viruses?

As previously discussed, miRNAs may inhibit viruses through direct targeting of viral genomes or transcripts. This concept is being exploited to create new and attenuated vaccines by incorporating miRNA response elements (miRNA target sequences) into viral vaccine genomes. When the virus enters a cell-type which expresses the miRNA which targets the miRNA response elements (MRE), the virus is attenuated. The virus is not attenuated in other cells not expressing that miRNA. In theory, this allows the creation of live vaccines which are attenuated in a tissue specific manner, maximizing efficacy while minimizing harm (see Figure 4 ).

What is the role of miRNAs in sepsis?

A promising application of miRNAs is to utilize their immunomodulatory functions to promote antimicrobial pathways during infection and control dysregulated inflammatory responses during sepsis. Hock et al., noted physiological downregulation of miR-328-3p in the lungs of mice infected with non-typeable Haemophilus influenza promoted phagocytosis by neutrophils and macrophages and bacterial killing and found boosting this downregulation by intra-tracheally administering an antagomiR (see Box 1) of miR-328-3p enhanced bacterial killing when mice were challenged with non-typeable H. influenza. Alexander et al. observed that administration of exosomes containing miR-146a and miR-155 ameliorated and enhanced mice inflammatory response to endotoxin in vivo, respectively, prompting the authors to speculate that such treatments could be useful adjuncts in managing sepsis (in the case of miR-146a) or vaccination (in the case of miR-155). Work by Wang et al. supports the notion that miRNA therapies could be a useful treatment in sepsis after they discovered administration of mesenchymal stem cell exosomes containing miR-223 confer cardiac protection in septic mice ( 192 ).

What is the name of the RNA that transcribes microRNA?

What is a miRNA cluster?

miRNA cluster: Some miRNA genes are found grouped together in polycistronic units with a shared promoter meaning they are transcribed together as a long primary transcript and are therefore coexpressed. E.g., miR-17-19 cluster. Micronome: The entire miRNA expression profile of a cell or sample.

Why are extracellular miRNAs used in RT-PCR?

Extracellular miRNAs are ideal biomarker candidates because they can be isolated from biological fluids ( 199 ). RT-PCR is already used routinely in the clinical setting to quickly identify infections (e.g., respiratory infections in babies with bronchiolitis) and could be used to quantify ex-miRNAs in patient samples.

Microrna - What It Is and How It Works

microRNA is the name of a family of molecules that helps cells control the kinds and amounts of proteins they make. That is, cells use microRNA to help control gene expression. Molecules of microRNA are found in cells and in the bloodstream. (Note: microRNA is abbreviated “miRNA,” but here we will use “microRNA” throughout.) Gene expression refers ...