In some aspects, the disclosure relates to compositions and methods useful for inhibiting SOD1 expression in cells (e.g., cells of a subject). In some embodiments, the disclosure describes isolated nucleic acids engineered to express an inhibitory nucleic acid targeting endogenous SOD1 and an mRNA encoding a hardened SOD1 protein. In some embodiments, compositions and methods described by the disclosure are useful for treating Amyotrophic Lateral Sclerosis (ALS) in a subject.