The present invention features, in certain aspects, methods of promoting endocytosis of LDL with α1PI or peptides derived from α1PI. The present invention also provides methods for decreasing LDL levels in response to α1PI augmentation therapy. In preferred embodiments, the methods are suitable for a subject who is suffering from a disease or disorder selected from heart disease, atherosclerosis, hypertension, HIV infection, viral infection, bacterial infection, leukemia, a solid tumor, or autoimmune disease.
