Improved tropoelastin synthesis in the skin by codon optimization and nucleotide modification of tropoelastin-encoding synthetic mRNA

Abstract

Loss of elastin due to aging, disease, or injury can lead to impaired tissue function. In this study, de novo tropoelastin (TE) synthesis is investigated invitro and invivo using different TE-encoding synthetic mRNA variants after codon optimization and nucleotide modification. Codon optimization shows a strong effect on protein synthesis without affecting cell viability invitro, whereas nucleotide modifications strongly modulate translation and reduce cell toxicity. Selected TE mRNA variants (3, 10, and 30μg) are then analyzed invivo in porcine skin after intradermal application. Administration of 30μg of native TE mRNA with a me1 Ψ modification or 10 and 30μg of unmodified codon-optimized TE mRNA is required to increase TE protein expression invivo. In contrast, just 3μg of a codon-optimized TE mRNA variant with the me1 Ψ modification is able to increase protein expression. Furthermore, skin toxicity is investigated invitro by injecting 30μg of mRNA of selected TE mRNA variants into a human full-thickness skin model, and no toxic effects are observed. Thereby, for the first time, an increased dermal TE synthesis by exogenous administration of synthetic mRNA is demonstrated invivo. Codon optimization of a synthetic mRNA can significantly increase protein expression and therapeutic outcome.