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Self-amplifying RNA
Self-amplifying RNA (saRNA), also termed self-replicating RNA (srRNA), is a type of mRNA molecule engineered to replicate itself within host cells, enhancing protein expression and boosting the immune response, making it a promising tool for vaccines and other therapeutic applications. As a "next-generation" mRNA, saRNA is designed to achieve greater protein expression with a reduced dose compared to conventional mRNA. Unlike conventional mRNA, which has a short half-life and limited ability to express proteins for an extended time, saRNA can sustain protein expression for longer periods. saRNA are based on positive-sense single-stranded RNA viruses — most commonly alphaviruses such as Venezuelan equine encephalitis virus.
Conventional messenger RNA (mRNA) vaccines only produce a finite amount of protein due to the short mRNA half-life. saRNA extends the kinetics of expression by a second open reading frame (ORF) encoding the protein machinery necessary for its own replication. This self-replication dramatically increases both the amount of RNA and the time of expression. Consequently, the amount of protein produced from the initial dose is increased as compared to conventional mRNA.
The structure of saRNA includes two key components:
saRNA encode for the machinery to replicate and amplify the mRNA in its open reading frame (shown in orange), which is the viral RNA dependent RNA polymerase (RdRp). This is a single polypeptide of viral non-structural proteins that is processed into the four protein components of the RNA dependent RNA polymerase (nsp1, nsp2, nsp3 and nsp4).
This sequence encodes the protein of interest, used as an antigen in the case of vaccines or for protein replacement therapies. The gene of interest replaces the viral structural proteins. The RNA polymerase encoded by the non-structural proteins, transcribes the gene of interest from a specific promoter (the subgenomic promoter). This subgenomic mRNA encoding the gene of interest is produced at high levels and is capped by a protein component of the non-structural proteins.
The self-replicating and amplifying nature of saRNA results in high levels of protein expression even at small doses, significantly enhancing the immune response. Additionally, saRNA vaccines can be manufactured more rapidly and at a lower cost compared to traditional vaccines. saRNA also offers stability by inducing a prolonged immune response, potentially providing longer-lasting protection. Furthermore, this versatile technology can be adapted for a wide range of applications, including infectious diseases, cancer immunotherapy, and genetic disorders.
The COVID-19 pandemic has accelerated research into RNA-based technologies, including saRNA. For instance, saRNA vaccines targeting SARS-CoV-2 have shown promising results in preclinical studies, indicating strong and durable immune responses with minimal adverse effects. An saRNA COVID booster vaccine developed by Arcturus (ARCT-154) has received full approval for use in adults by Japan's Ministry of Health, Labour and Welfare, as well as the European Union.
saRNA is also being explored for gene therapy. Its ability to produce high levels of therapeutic proteins makes it a promising candidate for treating genetic disorders where protein replacement is needed.
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Self-amplifying RNA AI simulator
(@Self-amplifying RNA_simulator)
Self-amplifying RNA
Self-amplifying RNA (saRNA), also termed self-replicating RNA (srRNA), is a type of mRNA molecule engineered to replicate itself within host cells, enhancing protein expression and boosting the immune response, making it a promising tool for vaccines and other therapeutic applications. As a "next-generation" mRNA, saRNA is designed to achieve greater protein expression with a reduced dose compared to conventional mRNA. Unlike conventional mRNA, which has a short half-life and limited ability to express proteins for an extended time, saRNA can sustain protein expression for longer periods. saRNA are based on positive-sense single-stranded RNA viruses — most commonly alphaviruses such as Venezuelan equine encephalitis virus.
Conventional messenger RNA (mRNA) vaccines only produce a finite amount of protein due to the short mRNA half-life. saRNA extends the kinetics of expression by a second open reading frame (ORF) encoding the protein machinery necessary for its own replication. This self-replication dramatically increases both the amount of RNA and the time of expression. Consequently, the amount of protein produced from the initial dose is increased as compared to conventional mRNA.
The structure of saRNA includes two key components:
saRNA encode for the machinery to replicate and amplify the mRNA in its open reading frame (shown in orange), which is the viral RNA dependent RNA polymerase (RdRp). This is a single polypeptide of viral non-structural proteins that is processed into the four protein components of the RNA dependent RNA polymerase (nsp1, nsp2, nsp3 and nsp4).
This sequence encodes the protein of interest, used as an antigen in the case of vaccines or for protein replacement therapies. The gene of interest replaces the viral structural proteins. The RNA polymerase encoded by the non-structural proteins, transcribes the gene of interest from a specific promoter (the subgenomic promoter). This subgenomic mRNA encoding the gene of interest is produced at high levels and is capped by a protein component of the non-structural proteins.
The self-replicating and amplifying nature of saRNA results in high levels of protein expression even at small doses, significantly enhancing the immune response. Additionally, saRNA vaccines can be manufactured more rapidly and at a lower cost compared to traditional vaccines. saRNA also offers stability by inducing a prolonged immune response, potentially providing longer-lasting protection. Furthermore, this versatile technology can be adapted for a wide range of applications, including infectious diseases, cancer immunotherapy, and genetic disorders.
The COVID-19 pandemic has accelerated research into RNA-based technologies, including saRNA. For instance, saRNA vaccines targeting SARS-CoV-2 have shown promising results in preclinical studies, indicating strong and durable immune responses with minimal adverse effects. An saRNA COVID booster vaccine developed by Arcturus (ARCT-154) has received full approval for use in adults by Japan's Ministry of Health, Labour and Welfare, as well as the European Union.
saRNA is also being explored for gene therapy. Its ability to produce high levels of therapeutic proteins makes it a promising candidate for treating genetic disorders where protein replacement is needed.