Measuring Hematocrit in Mice Injected with In Vitro-Transcribed Erythropoietin mRNA

A Facile Method for the Removal of dsRNA Contaminant from In Vitro-Transcribed mRNA

The increasing importance of in vitro-transcribed (IVT) mRNA for synthesizing the encoded therapeutic protein in vivo demands the manufacturing of pure mRNA products. The major contaminant in the IVT mRNA is double-stranded RNA (dsRNA), a transcriptional by-product that can be removed only by burdensome procedure requiring special instrumentation and generating hazardous waste. Here we present an alternative simple, fast, and cost-effective method involving only standard laboratory techniques. The purification of IVT mRNA is based on the selective binding of dsRNA to cellulose in an ethanol-containing buffer. We demonstrate that at least 90% of the dsRNA contaminants can be removed with a good, >65% recovery rate, regardless of the length, coding sequence, and nucleoside composition of the IVT mRNA. The procedure is scalable; purification of microgram or milligram amounts of IVT mRNA is achievable. Evaluating the impact of the mRNA purification in vivo in mice, increased translation could be measured for the administered transcripts, including the 1-methylpseudouridine-containing IVT mRNA, which no longer induced interferon (IFN)-α. The cellulose-based removal of dsRNA contaminants is an effective, reliable, and safe method to obtain highly pure IVT mRNA suitable for in vivo applications.

Cationic Nanoliposomes Meet mRNA: Efficient Delivery of Modified mRNA Using Hemocompatible and Stable Vectors for Therapeutic Applications

Synthetically modified mRNA is a unique bioactive agent, ideal for use in therapeutic applications, such as cancer vaccination or treatment of single-gene disorders. In order to facilitate mRNA transfections for future therapeutic applications, there is a need for the delivery system to achieve optimal transfection efficacy, perform with durable stability, and provide drug safety. The objective of our study was to comprehensively analyze the use of 3β-[N-(N',N'-dimethylaminoethane) carbamoyl](DC-Cholesterol)/dioleoylphosphatidylethanolamine (DOPE) liposomes as a potential transfection agent for modified mRNAs. Our cationic liposomes facilitated a high degree of mRNA encapsulation and successful cell transfection efficiencies. More importantly, no negative effects on cell viability or immune reactions were detected posttransfection. Notably, the liposomes had a long-acting transfection effect on cells, resulting in a prolonged protein production of alpha-1-antitrypsin (AAT). In addition, the stability of these mRNA-loaded liposomes allowed storage for 80 days, without the loss of transfection efficacy. Finally, comprehensive analysis showed that these liposomes are fully hemocompatible with fresh human whole blood. In summary, we present an extensive analysis on the use of DC-cholesterol/DOPE liposomes as mRNA delivery vehicles. This approach provides the basis of a safe and efficient therapeutic strategy in the development of successful mRNA-based drugs.