mRNA can direct dose-dependent protein expression in cardiac muscle without genome integration, but to date has not been shown to improve cardiac function in a safe, clinically applicable way. Herein, we report that a purified and optimized mRNA in a biocompatible citrate-saline formulation is tissue specific, long acting, and does not stimulate an immune response. In small- and large-animal, permanent occlusion myocardial infarction models, VEGF-A 165 mRNA improves systolic ventricular function and limits myocardial damage. Following a single administration a week post-infarction in mini pigs, left ventricular ejection fraction, inotropy, and ventricular compliance improved, border zone arteriolar and capillary density increased, and myocardial fibrosis decreased at 2 months post-treatment. Purified VEGF-A mRNA establishes the feasibility of improving cardiac function in the sub-acute therapeutic window and may represent a new class of therapies for ischemic injury.

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Abstract. Assembly of brain microtubule proteins isolated from the Atlantic cod, Gadus morhua, was found to be much less sensitive to colchicine than assembly of bovine brain microtubules, which was completely inhibited by low colchicine concentrations (10 #M). The degree of disassembly by colchicine was also less for cod microtubules. The lack of colchicine effect was not caused by a lower affinity of colchicine to cod tubulin, as colchicine bound to cod tubulin with a dissociation constant, Kd, and a binding ratio close to that of bovine tubulin.Cod brain tubulin was highly acetylated and mainly detyrosinated, as opposed to bovine tubulin. When cod tubulin, purified by means of phosphocellulose chromatography, was assembled by addition of DMSO in the absence of microtubule-associated proteins (MAPs), the microtubules became sensitive to low concentrations of colchicine. They were, however, slightly more stable to disassembly, indicating that posttranslational modifications induce a somewhat increased stability to colchicine. The stability was mainly MAPs dependent, as it increased markedly in the presence of MAPs. The stability was not caused by an extremely large amount of cod MAPs, since there were slightly less MAPs in cod than in bovine microtubules. When "hybrid" microtubules were assembled from cod tubulin and bovine MAPs, these microtubules became less sensitive to colchicine. This was not a general effect of MAPs, since bovine MAPs did not induce a colchicine stability of microtubules assembled from bovine tubulin. We can therefore conclude that MAPs can induce colchicine stability of colchicine labile acetylated tubulin.M ICROTUBULES constitute a dynamic part of the cytoskeleton in eukaryotic cells. They can be isolated for studies in vitro, and such studies show that microtubules are built of tubulin and several microtubule-associated proteins (MAPs) ~. Microtubule proteins in vitro reflect the dynamics in vivo, in that they can be brought through cycles of assembly and disassembly. Furthermore, they may be disassembled by several microtubule-disrupting agents, such as cold, Ca ~+ or colchicine.Previous studies have shown that an isolated fraction of cold-labile microtubules, from brains of the Atlantic cod (Gadus morhua) exhibit atypical features, i.e., they are not broken down by calcium, and they are associated with an unusual set of MAPs (Str/~mberg et al., 1989). In addition, neurophysiological studies on cod autonomic innervation, where Part of these results have been presented in preliminary form at the 4th Meeting of the European Cytoskeletal Club, held in Lyon, France, in 1988 (Billger, M., E. Strfmberg, and M. Wallin. 1988 colchicine was employed to increase the levels of neuropeptides in autonomic ganglia cells, failed, possibly due to an ineffectiveness of colchicine to disrupt cod axonal transport (Drs. S. Holmgren and A.-C. J/Snsson, Department of Zoophysiology, Comparative Neuroscience Unit, University of G~teborg, Sweden, personal communication). This observation might indicate that ...

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