Functional Loss of ABCA1 in Mice Causes Severe Placental Malformation, Aberrant Lipid Distribution, and Kidney Glomerulonephritis As Well As High-Density Lipoprotein Cholesterol Deficiency

Tangier disease (TD) and familial HDL deficiency (FHA) have recently been linked to mutations in the human ATP-binding cassette transporter 1 (hABCA1), a member of the ABC superfamily. Both diseases are characterized by the lowering or lack of high-density lipoprotein cholesterol (HDL-C) and low serum cholesterol. The murine ABCA1−/− phenotype corroborates the human TD linkage to ABCA1. Similar to TD in humans, HDL-C is virtually absent in ABCA1−/− mice accompanied by a reduction in serum cholesterol and lipid deposition in various tissues. In addition, the placenta of ABCA1−/− mice is malformed, resulting in severe embryo growth retardation, fetal loss, and neonatal death. The basis for these defects appears to be altered steroidogenesis, a direct result of the lack of HDL-C. By 6 months of age, ABCA1−/− animals develop membranoproliferative glomerulonephritis due to deposition of immunocomplexes followed by cardiomegaly with ventricular dilation and hypertrophy, ultimately succumbing to congestive heart failure. This murine model of TD will be very useful in the study of lipid metabolism, renal inflammation, and cardiovascular disease and may reveal previously unsuspected relationships between them.