Gene silencing is the regulation of gene expression in a cell to prevent the expression of a certain gene. Gene silencing can occur during either transcription or translation and is often used in research. In particular, methods used to silence genes are being increasingly used to produce therapeutics to combat cancer and other diseases, such as infectious diseases and neurodegenerative disorders.
Gene knockdown is an experimental technique by which the expression of one or more of an organism's genes is reduced. The reduction can occur either through genetic modification or by treatment with a reagent such as a short DNA or RNA oligonucleotide that has a sequence complementary to either gene or an mRNA transcript.
Small interfering RNA (siRNA), sometimes known as short interfering RNA or silencing RNA, is a class of double-stranded RNA at first non-coding RNA molecules, typically 20–24 base pairs in length, similar to miRNA, and operating within the RNA interference (RNAi) pathway. It interferes with the expression of specific genes with complementary nucleotide sequences by degrading mRNA after transcription, preventing translation.
Antisense therapy is a form of treatment that uses antisense oligonucleotides (ASOs) to target messenger RNA (mRNA). ASOs are capable of altering mRNA expression through a variety of mechanisms, including ribonuclease H mediated decay of the pre-mRNA, direct steric blockage, and exon content modulation through splicing site binding on pre-mRNA. Several ASOs have been approved in the United States, the European Union, and elsewhere.
A short hairpin RNA or small hairpin RNA is an artificial RNA molecule with a tight hairpin turn that can be used to silence target gene expression via RNA interference (RNAi). Expression of shRNA in cells is typically accomplished by delivery of plasmids or through viral or bacterial vectors. shRNA is an advantageous mediator of RNAi in that it has a relatively low rate of degradation and turnover. However, it requires use of an expression vector, which has the potential to cause side effects in medicinal applications.
RNA silencing or RNA interference refers to a family of gene silencing effects by which gene expression is negatively regulated by non-coding RNAs such as microRNAs. RNA silencing may also be defined as sequence-specific regulation of gene expression triggered by double-stranded RNA (dsRNA). RNA silencing mechanisms are conserved among most eukaryotes. The most common and well-studied example is RNA interference (RNAi), in which endogenously expressed microRNA (miRNA) or exogenously derived small interfering RNA (siRNA) induces the degradation of complementary messenger RNA. Other classes of small RNA have been identified, including piwi-interacting RNA (piRNA) and its subspecies repeat associated small interfering RNA (rasiRNA).
Quark Pharmaceuticals is a pharmaceutical company that develops RNA interference-based treatments for chronic and acute diseases.
Proprotein convertase subtilisin/kexin type 9 (PCSK9) is an enzyme encoded by the PCSK9 gene in humans on chromosome 1. It is the 9th member of the proprotein convertase family of proteins that activate other proteins. Similar genes (orthologs) are found across many species. As with many proteins, PCSK9 is inactive when first synthesized, because a section of peptide chains blocks their activity; proprotein convertases remove that section to activate the enzyme. The PCSK9 gene also contains one of 27 loci associated with increased risk of coronary artery disease.
Stable nucleic acid lipid particles (SNALPs) are microscopic particles approximately 120 nanometers in diameter, smaller than the wavelengths of visible light. They have been used to deliver siRNAs therapeutically to mammals in vivo. In SNALPs, the siRNA is surrounded by a lipid bilayer containing a mixture of cationic and fusogenic lipids, coated with diffusible polyethylene glycol.
RNA interference (RNAi) is a biological process in which RNA molecules are involved in sequence-specific suppression of gene expression by double-stranded RNA, through translational or transcriptional repression. Historically, RNAi was known by other names, including co-suppression, post-transcriptional gene silencing (PTGS), and quelling. The detailed study of each of these seemingly different processes elucidated that the identity of these phenomena were all actually RNAi. Andrew Fire and Craig C. Mello shared the 2006 Nobel Prize in Physiology or Medicine for their work on RNAi in the nematode worm Caenorhabditis elegans, which they published in 1998. Since the discovery of RNAi and its regulatory potentials, it has become evident that RNAi has immense potential in suppression of desired genes. RNAi is now known as precise, efficient, stable and better than antisense therapy for gene suppression. Antisense RNA produced intracellularly by an expression vector may be developed and find utility as novel therapeutic agents.
Santaris Pharma A/S was a biopharmaceutical company founded in 2003 in Copenhagen, Denmark. The company also had a branch in San Diego, California that opened in 2009. Created by a merger between Cureon and Pantheco, Santaris developed RNA-targeted medicines using a Locked Nucleic Acid (LNA) Drug Platform and Drug Development Engine.
DNA-directed RNA interference (ddRNAi) is a gene-silencing technique that utilizes DNA constructs to activate an animal cell's endogenous RNA interference (RNAi) pathways. DNA constructs are designed to express self-complementary double-stranded RNAs, typically short-hairpin RNAs, that bring about the silencing of a target gene or genes once processed. Any RNA, including endogenous messenger RNA (mRNAs) or viral RNAs, can be silenced by designing constructs to express double-stranded RNA complementary to the desired mRNA target.
Alnylam Pharmaceuticals, Inc. is an American biopharmaceutical company focused on the discovery, development and commercialization of RNA interference (RNAi) therapeutics for genetically defined diseases. The company was founded in 2002 and is headquartered in Cambridge, Massachusetts. In 2016, Forbes included the company on its "100 Most Innovative Growth Companies" list.
Arcturus Therapeutics Holdings Inc. is an American RNA medicines biotechnology company focused on the discovery, development and commercialization of therapeutics for rare diseases and infectious diseases. Arcturus has developed proprietary lipid nanoparticle RNA therapeutics for nucleic acid medicines including small interfering RNA (siRNA), messenger RNA (mRNA), gene editing RNA, DNA, antisense oligonucleotides, and microRNA.
Ionis Pharmaceuticals, Inc. is a biotechnology company based in Carlsbad, California, that specializes in discovering and developing RNA-targeted therapeutics. The company has three commercially approved medicines: Spinraza (Nusinersen), Tegsedi (Inotersen), and Waylivra (Volanesorsen) and has four drugs in pivotal studies: tominersen for Huntington’s disease, tofersen for SOD1-ALS, AKCEA-APO(a)-LRx for cardiovascular disease, and AKCEA-TTR-LRx for all forms of TTR amyloidosis.
Inclisiran, sold under the brand name Leqvio, is a medication used for the treatment of high low-density lipoprotein (LDL) cholesterol and for the treatment of people with atherosclerotic cardiovascular disease (ASCVD), ASCVD risk-equivalents, and heterozygous familial hypercholesterolemia (HeFH). It is a small interfering RNA (siRNA) that acts as an inhibitor of a proprotein convertase, specifically, inhibiting translation of the protein PCSK9.
ProQR Therapeutics NV is a Dutch biotechnology company based in Leiden, the Netherlands, with a presence in Cambridge, Massachusetts, US. The company was funded in 2012 by chief executive officer (CEO) Daniel A. de Boer. It specializes in the development of RNA therapeutics using its RNA editing platform technology called Axiomer.
RNA therapeutics are a new class of medications based on ribonucleic acid (RNA). Research has been working on clinical use since the 1990s, with significant success in cancer therapy in the early 2010s. In 2020 and 2021, mRNA vaccines have been developed globally for use in combating the coronavirus disease. The Pfizer–BioNTech COVID-19 vaccine was the first mRNA vaccine approved by a medicines regulator, followed by the Moderna COVID-19 vaccine, and others.
Vutrisiran, previously known as (ALN-TTRSC02), sold under the brand name Amvuttra, is a medication used for the treatment of the polyneuropathy of hereditary transthyretin-mediated (hATTR) amyloidosis in adults. It is a double stranded small interfering RNA (siRNA) that interferes with the expression of the transthyretin (TTR) gene. Transthyretin is a serum protein made in the liver whose major function is transport of vitamin A and thyroxine. Rare mutations in the transthyretin gene result in accumulation of large amyloid deposits of misfolded transthyretin molecules most prominently in peripheral nerves and the heart. Patients with hATTR typically present with polyneuropathy or autonomic dysfunction followed by cardiomyopathy which, if untreated, is fatal within 5 to 10 years.
Lepodisiran (LY3819469) is a small interfering RNA that was developed to reduce lipoprotein(a) in people at risk of cardiovascular disease. It was developed by Eli Lilly and Company.
