mRNA, or messenger RNA, is a type of molecule that carries genetic information from DNA to the protein-making machinery of the cell. By delivering mRNA into cells, we can instruct them to produce any protein we want, such as antibodies, enzymes, hormones, or vaccines. This opens up a new world of possibilities for treating various diseases, from infectious diseases to cancer.
In this article, we will introduce you to the basics of mRNA therapy, including how it works, how it is made, how it is delivered, and how it is applied. We will also share some of the latest advances and challenges in this exciting field of biotechnology.
How does mRNA therapy work?
mRNA therapy works by introducing synthetic mRNA molecules into cells, where they are translated into functional proteins. Depending on the type and purpose of the protein, mRNA therapy can have different effects. For example:
mRNA vaccines can trigger an immune response against a specific pathogen, such as the novel coronavirus that causes COVID-19. By delivering mRNA that encodes a viral protein, such as the spike protein, we can stimulate the production of antibodies and T cells that can recognize and eliminate the virus.
mRNA antibodies can provide passive immunity against a disease, such as rabies or HIV. By delivering mRNA that encodes a monoclonal antibody, we can confer immediate protection against a specific antigen, without relying on the body's own immune system.
mRNA protein replacement can restore the function of a missing or defective protein, such as factor VIII in hemophilia or dystrophin in muscular dystrophy. By delivering mRNA that encodes a normal version of the protein, we can correct the underlying cause of the disease and improve the symptoms.
mRNA gene editing can modify the genome of a cell, such as correcting a mutation or inserting a new gene. By delivering mRNA that encodes a programmable nucleases, such as CRISPR/Cas9, we can target and edit specific DNA sequences with high precision and efficiency.
How is mRNA made?
mRNA is made by a process called in vitro transcription (IVT), which uses a DNA template and an RNA polymerase enzyme to synthesize RNA molecules. The DNA template contains a promoter sequence and the coding sequence of the desired protein. The RNA polymerase binds to the promoter and transcribes the DNA into RNA.
To ensure that the synthetic mRNA is functional and stable in cells, several modifications are made during or after IVT. These include:
Capping: adding a modified nucleotide to the 5' end of the mRNA to protect it from degradation and enhance its translation efficiency. There are different types of caps, such as Cap 0, Cap 1, and Cap 2, which differ in their methylation levels.
Polyadenylation: adding a string of adenine nucleotides to the 3' end of the mRNA to increase its stability and half-life. The length of the poly(A) tail can vary from 10 to 250 nucleotides.
Optimization: adjusting the structural components of the mRNA, such as the 5' untranslated region (UTR), the 3' UTR, and the open reading frame (ORF), to improve its expression level and activity. This may involve optimizing the codon usage, introducing functional peptides or signal sequences, or adding self-amplifying elements.
Modification: altering the chemical structure of some nucleotides in the mRNA to reduce its immunogenicity and increase its stability. This may involve replacing uridine with pseudouridine or N1-methylpseudouridine, or adding methyl groups to other positions.
How is mRNA delivered?
mRNA delivery is one of the biggest challenges in mRNA therapy, as mRNA molecules are large, negatively charged, and prone to degradation by enzymes in biological fluids. Therefore, various types of carriers are developed to protect and transport mRNA into cells. These include:
Lipid nanoparticles (LNPs): spherical particles composed of lipids that form a bilayer around mRNA molecules. LNPs can fuse with cell membranes and release mRNA into the cytoplasm. LNPs are widely used for mRNA delivery due to their high efficiency and biocompatibility. Some examples of LNPs are cationic solid lipid nanoparticles (SLNs), ionizable lipid nanoparticles (ILNs), and immunostimulatory lipid nanoparticles (ISLNs).
Polymer nanoparticles (PNPs): spherical particles composed of polymers that form a core-shell structure around mRNA molecules. PNPs can enter cells by endocytosis and escape from lysosomes by proton sponge effect or enzymatic degradation. PNPs are versatile and customizable for different applications. Some examples of PNPs are polyethylenimine (PEI), poly(lactic-co-glycolic acid) (PLGA), and chitosan.
Cationic nanoemulsions (CNEs): droplets of oil-in-water emulsions that contain cationic lipids and surfactants. CNEs can interact with cell membranes and deliver mRNA into the cytoplasm. CNEs are easy to prepare and scale up, and can enhance the immunogenicity of mRNA vaccines. Some examples of CNEs are DOTAP/DOPE, DOTAP/cholesterol, and DOTAP/MCT.
Other mRNA delivery systems: some other types of carriers that have been explored for mRNA delivery are protamine-condensed mRNA, exosomes, extracellular vesicles (EVs), mesoporous silica, and calcium phosphate (CaP).
What are the applications of mRNA therapy?
mRNA therapy has the potential to treat a wide range of diseases, from infectious diseases to metabolic disorders, from cancer to cardiovascular diseases, and from genetic diseases to regenerative medicine. Some of the current and emerging applications of mRNA therapy are:
mRNA vaccines: mRNA vaccines can induce a robust and specific immune response against various pathogens, such as SARS-CoV-2, influenza virus, HIV, respiratory syncytial virus (RSV), herpes simplex virus (HSV), varicella zoster virus (VZV), human cytomegalovirus (HCMV), rabies virus, and dengue virus. mRNA vaccines have several advantages over traditional vaccines, such as rapid development, low cost, high safety, and easy scalability.
mRNA antibodies: mRNA antibodies can provide passive immunity against various diseases, such as rabies, HIV, Ebola, Zika, anthrax, and COVID-19. mRNA antibodies have several advantages over conventional antibodies, such as long-term expression, low immunogenicity, high stability, and easy administration.
mRNA protein replacement: mRNA protein replacement can restore the function of a missing or defective protein in various diseases, such as hemophilia, muscular dystrophy, cystic fibrosis, phenylketonuria, Fabry disease, Gaucher disease, and Parkinson's disease. mRNA protein replacement has several advantages over protein therapy, such as avoiding immunogenicity, enhancing bioavailability, and reducing dosage and frequency.
mRNA gene editing: mRNA gene editing can modify the genome of a cell in various diseases, such as sickle cell anemia, beta-thalassemia, Huntington's disease, Duchenne muscular dystrophy, and cystic fibrosis. mRNA gene editing has several advantages over DNA-based gene therapy, such as avoiding integration into the host genome, reducing off-target effects, and increasing specificity and efficiency.
mRNA cell therapy: mRNA cell therapy can manipulate the function of a cell in various diseases, such as cancer, autoimmune diseases, diabetes, and cardiovascular diseases. mRNA cell therapy has several advantages over conventional cell therapy, such as avoiding viral vectors, enhancing safety and versatility, and facilitating manufacturing and quality control.
What are the challenges and opportunities of mRNA therapy?
mRNA therapy is a promising and emerging field of biotechnology that has shown great potential in treating various diseases. However, there are still some challenges and limitations that need to be overcome before it can be widely applied in clinical practice. These include:
-Improving the stability and delivery efficiency of mRNA molecules in vivo
-Reducing the immunogenicity and toxicity of mRNA molecules and carriers
-Optimizing the expression level and duration of mRNA-encoded proteins
-Developing standardized protocols and quality control measures for mRNA production
-Evaluating the long-term safety and efficacy of mRNA therapy in humans
-Despite these challenges, there are also many opportunities and advantages that make mRNA therapy an attractive option for future medicine. These include:
-Exploiting the flexibility and diversity of mRNA design and synthesis
-Leveraging the inherent immunogenicity and adjuvanticity of mRNA molecules
-Harnessing the transient expression and reversibility of mRNA-encoded proteins
-Exploring the synergistic effects of combining mRNA therapy with other modalities
-Accelerating the development and approval process of mRNA products
Prisys Biotechnology, a company that specializes in non-human primate (NHP) research and services for preclinical drug development. mRNA therapy, a type of molecule that can instruct cells to produce any protein we want, such as antibodies, enzymes, hormones, or vaccines. Cynomolgus macaques, a species of NHP that share many similarities with humans in terms of anatomy, physiology, immunology, and genetics. Prisys Biotechnology in mRNA drug research and development and NHP models as follows:
Prisys Biotechnology has an integrated platform of NHP resources, disease models, and clinical hospitals to provide solutions for various disease areas, such as immunology, inflammation, cardiovascular diseases, hematology, liver, kidney, lung, and oncology.
Prisys Biotechnology offers cooperative development options for R&D collaborations and innovative technologies such as deep learning-based 3D behavioral quantification system in NHP.
Prisys Biotechnology uses cynomolgus macaques as the animal model for mRNA therapy, which are more reliable and relevant than other animal models, such as mice or rats.
Prisys Biotechnology can test the potential and feasibility of mRNA therapy for various diseases by measuring the electrical resistance, magnetic properties, pharmacokinetics, toxicity, immunogenicity, and efficacy of mRNA molecules and carriers in NHPs.
