Compositions are provided comprising messenger RNA constructs having at least one open reading frame (ORF), wherein the ORF is operatively linked to at least one untranslated region (UTR), wherein the UTR comprises at least one organ protection sequence (OPS), wherein the OPS sequence comprises at least a first, a second and a third micro-RNA (miRNA) target sequence, and wherein each of the at least a first, second and third the miRNA target sequences are optimised to hybridise with a corresponding miRNA sequence. The compositions and molecules provided are useful in therapies such as for the treatment of cancer, in immunotherapies, and in vaccines.