Degradation of cationized low density lipoprotein and regulation of cholesterol metabolism in homozygous familial hypercholesterolemia fibroblasts.
AUTOR(ES)
Basu, S K
RESUMO
Cultured fibroblasts derived from patients with homozygous familial hypercholesterolemia, which lack functional low density lipoprotein (LDL) receptors, fail to bind, take up, or degrade the lipoprotein with high affinity; therefore LDL-cholesterol is not made available for suppression of cholesterol synthesis or activation of cholesteryl ester formation. When LDL was given a positive charge by reaction with N,N-dimethyl-1,3-propanediamine (cationized LDL), the rate of degradation of the lipoprotein was increased by more than 100-fold in the homozygous familial hypercholesterolemia fibroblasts. Degradation of cationized LDL was inhibited by chloroquine, suggesting that it occurred in cellular lysosomes. Although the cationized LDL entered the cell through a mechanism independent of the LDL receptor, the cholesterol liberated from the degradation of the lipoprotein became available for suppression of cholesterol synthesis and stimulation of cholesteryl ester formation in the homozygous familial hypercholesterolemia fibroblasts. The rate of degradation of albumin by fibroblasts was also increased by more than 100-fold when this protein was coupled to N,N-dimethyl-1,3-propanediamine. The ability to deliver a protein to lysosomes by giving it a strong positive charge may have potential relevance not only to familial hypercholesterolemia, but also to inborn errors of metabolism that involve deficiencies in lysosomal enzymes.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=430973Documentos Relacionados
- Esterification of Low Density Lipoprotein Cholesterol in Human Fibroblasts and Its Absence in Homozygous Familial Hypercholesterolemia
- Binding, internalization, and degradation of low density lipoprotein by normal human fibroblasts and by fibroblasts from a case of homozygous familial hypercholesterolemia.
- Reduction in cholesterol and low density lipoprotein synthesis after portacaval shunt surgery in a patient with homozygous familial hypercholesterolemia.
- Characterization of hepatic low density lipoprotein binding and cholesterol metabolism in normal and homozygous familial hypercholesterolemic subjects.
- Homozygous familial hypercholesterolemia mutant with a defect in internalization of low density lipoprotein.