https://phaidra.vetmeduni.ac.at/o:2489 Improved tropoelastin synthesis in the skin by codon optimization and nucleotide modification of tropoelastin-encoding synthetic mRNA Golombek, Sonia Sonia Golombek University Hospital Tübingen Avci-Adali, Meltem Meltem Avci-Adali University Hospital Tübingen Schneeberger, Achim Achim Schneeberger Accanis Biotech Wendel, Hans Peter Hans Peter Wendel University Hospital Tübingen Schlensak, Christian Christian Schlensak University Hospital Tübingen Leyens, Johanna Johanna Leyens University Hospital Tübingen Knecht, Christian Christian Knecht University of Veterinary Medicine Vienna Ladinig, Andrea Andrea Ladinig 0000-0001-5037-7269 University of Veterinary Medicine Vienna Mehling, Roman Roman Mehling Eberhard Karls University Chang, Young-Tae Young-Tae Chang Pohang University of Science and Technology Weber, Josefin Josefin Weber University Hospital Tübingen Schmidhuber, Sabine Sabine Schmidhuber Accanis Biotech Mandler, Markus Markus Mandler Accanis Biotech Hoffmann, Thomas Thomas Hoffmann Accanis Biotech Hann, Ludmilla Ludmilla Hann University Hospital Tübingen Cell Press text eng 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 in vitro and in vivo 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 in vitro, whereas nucleotide modifications strongly modulate translation and reduce cell toxicity. Selected TE mRNA variants (3, 10, and 30 μg) are then analyzed in vivo in porcine skin after intradermal application. Administration of 30 μg of native TE mRNA with a me1 Ψ modification or 10 and 30 μg of unmodified codon-optimized TE mRNA is required to increase TE protein expression in vivo. In contrast, just 3 μg of a codon-optimized TE mRNA variant with the me1 Ψ modification is able to increase protein expression. Furthermore, skin toxicity is investigated in vitro by injecting 30 μg 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 in vivo. Codon optimization of a synthetic mRNA can significantly increase protein expression and therapeutic outcome. Elastic Fibers; In-Vivo; Expression; Immunogenicity; Activation; Design; Health http://creativecommons.org/licenses/by/4.0/ https://phaidra.vetmeduni.ac.at/api/object/o:2489/download 10.1016/j.omtn.2023.07.035 https://phaidra.vetmeduni.ac.at/o:605 application/pdf Molecular therapy. Nucleic acids 33, 642-654 (2023) Molecular therapy. Nucleic acids 33 642 654 2.80 MB 2023