Disclosed herein are compositions, constructs, cassettes, vectors, cells, nucleic acids, peptides, proteins, protocols and methods for reducing cholesterol and lipid buildup in mammalian subjects, via gene and/or cell therapeutic treatments. In many embodiments, the disclosed compositions, cells, constructs, cassettes, vectors, nucleic acids, peptides, proteins, protocols and methods may help to reduce lipid levels in mammals. In one embodiment, the disclosed compositions, cells, constructs, cassettes, vectors, nucleic acids, peptides, proteins, protocols and methods are useful in reducing lipid build-up, especially cholesterol, in liver cells.