Application of quantitative and engineering biology in mRNA gene therapy

As a transient vector of gene information, messenger RNA (mRNA) is a multifunctional, flexible and safe gene therapy. However, due to the general instability and immunogenicity of mRNA molecules, mRNA gene therapy has not been popularized at first. Over the past few decades, the cross-integration of quantitative and engineering biology has led to a gradual shift from the concept validation phase to the clinical treatment phase. In this paper, we discussed the application of quantitative and engineering biology in mRNA gene therapy from the functional structure of mRNA, design and technical innovation of in vitro synthetic mRNA. Effective engineering approaches will help to establish a precise mRNA gene therapy platform for a variety of indications and genetic backgrounds. Although mRNA therapy is still in the pre-clinical phase in most indications, the accumulation of various engineering and quantitative bio-design methods may broaden the path for next-generation mRNA gene therapy. mRNA is an intermediate of genetic information and a template for the biological expression of proteins. Therefore, exogenous mRNA can be introduced into target cells to express the protein of interest. In the early 1970s, Gurdon first verified the above concept in Xenopus oocytes using microinjection. The advantages of mRNA-based gene therapy methods are: First, mRNA therapy has a broader application. mRNA does not need to enter the nucleus to express proteins in the cytoplasm to achieve its function. Therefore, mRNA can be played in cells that divide slowly or do not divide role. Second, mRNA therapy has higher safety, due to its transient expression and the extremely low possibility of genome integration, thereby reducing the two main risks associated with gene therapy (host genome integration and mutations in key regions). Third, the half-life and expression abundance of mRNA synthesized in vitro can be determined by the structure and component design, so that the pharmacokinetics of mRNA drugs can be better controlled. This has created favorable conditions for the pharmaceutical good manufacturing practice (GMP) of mRNA synthetic drugs. In addition, therapeutic proteins synthesized using the natural mechanism of cells have natural post-translational modifications and suitable protein folding effects, which are more advantageous than recombinant proteins synthesized in vitro. In recent years, mRNA, as a therapeutic method, has received increasing attention in the field of gene therapy. Currently, in vitro-transcribed (IVT) mRNA has been used in pre-clinical and clinical trials, including cancer treatment, vaccine development, and protein replacement drug development. Compared with cancer and vaccine treatment, most protein replacement therapies using mRNA are still in preclinical development stage.