Provided herein are engineered nucleic acids (e.g., expression vectors, including viral vectors, such as lentiviral vectors, adenoviral vectors, AAV vectors, herpes viral vectors, and retroviral vectors) that encode OCT4; KLF4; SOX2; or any combination thereof that are useful, for example, in inducing cellular reprogramming, tissue repair, tissue regeneration, organ regeneration, reversing aging, or any combination thereof in the central nervous system or ex vivo. Also provided herein are recombinant viruses (e.g., lentiviruses, alphaviruses, vaccinia viruses, adenoviruses, herpes viruses, retroviruses, or AAVs) comprising the engineered nucleic acids (e.g., engineered nucleic acids), engineered cells, compositions comprising the engineered nucleic acids, the recombinant viruses, engineered cells, engineered proteins, chemical agents that are capable of activating expression of OCT4; KLF4; SOX2; or any combination thereof, an engineered protein selected from the group consisting of OCT4; KLF4; SOX2; or any combination thereof, an antibody capable of activating expression of OCT4; KLF4; SOX2; or any combination thereof, and methods of treating a disease (e.g., a neurological disease), preventing a disease (e.g., neurological disease), regulating (e.g., inducing or inducing and then stopping) cellular reprogramming, regulating tissue repair, regulating tissue regeneration, or any combination thereof.

Methods of treating cardiac hypertrophy or cardiomyocyte hypertrophy, or methods of inhibiting progression of heart failure in a subject in need thereof, in which the methods comprise administering a pharmaceutical composition comprising an effective amount of a conjugate comprising microRNA and a cardiac targeting peptide. In addition, methods of inhibiting expression of Ca2+/calmodulin-dependent protein kinase II delta or histone deacetylase 4 in cardiomyocytes, in which the methods comprise contacting the cardiomyocytes with a conjugate comprising microRNA and a cardiac targeting peptide. The microRNA may be mi RN A 106a. miRNA17, miRNA20a, or miRNA93.