Low-density lipoprotein endocytosis. II. Influence of the multivalent ligand cationized ferritin on acetylated low-density lipoprotein endocytosis in cultured cells

Eugene A Sprague, Ellen H. Edwards, Anthony J. Valente, C. Alan Suenram, James J. Kerbacher, Colin J. Schwartz

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

Interactions of the basic multivalent ligand cationized ferritin (CF) with cultured cells markedly alter their endocytic function. In this study, the influence of CF treatment on the binding, internalization, and degradation of chemically modified (acetylated) low-density lipoproteins (Ac-LDL) was examined in aortic smooth muscle cells (SMC); and in normal and FH mutant LDL receptor-negative human skin fibroblasts, which lack the Ac-LDL (scavenger) receptor; and in vascular endothelial cells, which normally express the receptor. Although CF treatment of all three cell types at 37°C resulted in the induction of Pronasesensitive, high-capacity, high-affinity binding (Kd = 12.0 ± 2.0 nM at 4°C) of labeled Ac-LDL, which at 37°C was accompanied by significant internalization and degradation, these processes were not receptor-mediated. CF-induced high-affinity binding was inhibited by unlabeled Ac-LDL, fucoidan, carrageenan, and dextran sulfate but was unaffected by native LDL and albumin and only partially inhibited by acetylated albumin. However, analysis of membrane preparations of the cells for "scavenger" receptor protein by solid-phase filtration assay and Western blotting identified the receptor in endothelial cells and in granuloma (positive control) macrophages, but not in either CF-treated or untreated SMC. In addition, studies with both glutaraldehyde-fixed cells and CF bound to culture dishes indicated that Ac-LDL avidly binds to CF. Further, ultrastructural studies using colloidal gold-conjugated Ac-LDL showed Ac-LDL preferentially binding to CF aggregates on the cell surface. Thus, these studies indicate that treatment of cells with CF induces an endocytic process which, although remarkably similar to the scavenger pathway, is mediated by Ac-LDL binding to membrane-associated CF. These observations have implications in terms of mechanisms that might regulate the endocytosis of modified low-density lipoproteins.

Original languageEnglish (US)
Pages (from-to)373-390
Number of pages18
JournalExperimental and Molecular Pathology
Volume48
Issue number3
DOIs
StatePublished - 1988

Fingerprint

Endocytosis
LDL Lipoproteins
Cultured Cells
Cells
Ligands
Scavenger Receptors
LDL Receptors
Endothelial cells
Smooth Muscle Myocytes
Muscle
Albumins
Endothelial Cells
polycationic ferritin
acetyl-LDL
Membranes
Gold Colloid
Degradation
Dextran Sulfate
Macrophages
Carrageenan

ASJC Scopus subject areas

  • Clinical Biochemistry
  • Molecular Biology
  • Pathology and Forensic Medicine

Cite this

Low-density lipoprotein endocytosis. II. Influence of the multivalent ligand cationized ferritin on acetylated low-density lipoprotein endocytosis in cultured cells. / Sprague, Eugene A; Edwards, Ellen H.; Valente, Anthony J.; Suenram, C. Alan; Kerbacher, James J.; Schwartz, Colin J.

In: Experimental and Molecular Pathology, Vol. 48, No. 3, 1988, p. 373-390.

Research output: Contribution to journalArticle

Sprague, Eugene A ; Edwards, Ellen H. ; Valente, Anthony J. ; Suenram, C. Alan ; Kerbacher, James J. ; Schwartz, Colin J. / Low-density lipoprotein endocytosis. II. Influence of the multivalent ligand cationized ferritin on acetylated low-density lipoprotein endocytosis in cultured cells. In: Experimental and Molecular Pathology. 1988 ; Vol. 48, No. 3. pp. 373-390.
@article{ec32b66747c244ca8447794d204fdf51,
title = "Low-density lipoprotein endocytosis. II. Influence of the multivalent ligand cationized ferritin on acetylated low-density lipoprotein endocytosis in cultured cells",
abstract = "Interactions of the basic multivalent ligand cationized ferritin (CF) with cultured cells markedly alter their endocytic function. In this study, the influence of CF treatment on the binding, internalization, and degradation of chemically modified (acetylated) low-density lipoproteins (Ac-LDL) was examined in aortic smooth muscle cells (SMC); and in normal and FH mutant LDL receptor-negative human skin fibroblasts, which lack the Ac-LDL (scavenger) receptor; and in vascular endothelial cells, which normally express the receptor. Although CF treatment of all three cell types at 37°C resulted in the induction of Pronasesensitive, high-capacity, high-affinity binding (Kd = 12.0 ± 2.0 nM at 4°C) of labeled Ac-LDL, which at 37°C was accompanied by significant internalization and degradation, these processes were not receptor-mediated. CF-induced high-affinity binding was inhibited by unlabeled Ac-LDL, fucoidan, carrageenan, and dextran sulfate but was unaffected by native LDL and albumin and only partially inhibited by acetylated albumin. However, analysis of membrane preparations of the cells for {"}scavenger{"} receptor protein by solid-phase filtration assay and Western blotting identified the receptor in endothelial cells and in granuloma (positive control) macrophages, but not in either CF-treated or untreated SMC. In addition, studies with both glutaraldehyde-fixed cells and CF bound to culture dishes indicated that Ac-LDL avidly binds to CF. Further, ultrastructural studies using colloidal gold-conjugated Ac-LDL showed Ac-LDL preferentially binding to CF aggregates on the cell surface. Thus, these studies indicate that treatment of cells with CF induces an endocytic process which, although remarkably similar to the scavenger pathway, is mediated by Ac-LDL binding to membrane-associated CF. These observations have implications in terms of mechanisms that might regulate the endocytosis of modified low-density lipoproteins.",
author = "Sprague, {Eugene A} and Edwards, {Ellen H.} and Valente, {Anthony J.} and Suenram, {C. Alan} and Kerbacher, {James J.} and Schwartz, {Colin J.}",
year = "1988",
doi = "10.1016/0014-4800(88)90072-X",
language = "English (US)",
volume = "48",
pages = "373--390",
journal = "Experimental and Molecular Pathology",
issn = "0014-4800",
publisher = "Academic Press Inc.",
number = "3",

}

TY - JOUR

T1 - Low-density lipoprotein endocytosis. II. Influence of the multivalent ligand cationized ferritin on acetylated low-density lipoprotein endocytosis in cultured cells

AU - Sprague, Eugene A

AU - Edwards, Ellen H.

AU - Valente, Anthony J.

AU - Suenram, C. Alan

AU - Kerbacher, James J.

AU - Schwartz, Colin J.

PY - 1988

Y1 - 1988

N2 - Interactions of the basic multivalent ligand cationized ferritin (CF) with cultured cells markedly alter their endocytic function. In this study, the influence of CF treatment on the binding, internalization, and degradation of chemically modified (acetylated) low-density lipoproteins (Ac-LDL) was examined in aortic smooth muscle cells (SMC); and in normal and FH mutant LDL receptor-negative human skin fibroblasts, which lack the Ac-LDL (scavenger) receptor; and in vascular endothelial cells, which normally express the receptor. Although CF treatment of all three cell types at 37°C resulted in the induction of Pronasesensitive, high-capacity, high-affinity binding (Kd = 12.0 ± 2.0 nM at 4°C) of labeled Ac-LDL, which at 37°C was accompanied by significant internalization and degradation, these processes were not receptor-mediated. CF-induced high-affinity binding was inhibited by unlabeled Ac-LDL, fucoidan, carrageenan, and dextran sulfate but was unaffected by native LDL and albumin and only partially inhibited by acetylated albumin. However, analysis of membrane preparations of the cells for "scavenger" receptor protein by solid-phase filtration assay and Western blotting identified the receptor in endothelial cells and in granuloma (positive control) macrophages, but not in either CF-treated or untreated SMC. In addition, studies with both glutaraldehyde-fixed cells and CF bound to culture dishes indicated that Ac-LDL avidly binds to CF. Further, ultrastructural studies using colloidal gold-conjugated Ac-LDL showed Ac-LDL preferentially binding to CF aggregates on the cell surface. Thus, these studies indicate that treatment of cells with CF induces an endocytic process which, although remarkably similar to the scavenger pathway, is mediated by Ac-LDL binding to membrane-associated CF. These observations have implications in terms of mechanisms that might regulate the endocytosis of modified low-density lipoproteins.

AB - Interactions of the basic multivalent ligand cationized ferritin (CF) with cultured cells markedly alter their endocytic function. In this study, the influence of CF treatment on the binding, internalization, and degradation of chemically modified (acetylated) low-density lipoproteins (Ac-LDL) was examined in aortic smooth muscle cells (SMC); and in normal and FH mutant LDL receptor-negative human skin fibroblasts, which lack the Ac-LDL (scavenger) receptor; and in vascular endothelial cells, which normally express the receptor. Although CF treatment of all three cell types at 37°C resulted in the induction of Pronasesensitive, high-capacity, high-affinity binding (Kd = 12.0 ± 2.0 nM at 4°C) of labeled Ac-LDL, which at 37°C was accompanied by significant internalization and degradation, these processes were not receptor-mediated. CF-induced high-affinity binding was inhibited by unlabeled Ac-LDL, fucoidan, carrageenan, and dextran sulfate but was unaffected by native LDL and albumin and only partially inhibited by acetylated albumin. However, analysis of membrane preparations of the cells for "scavenger" receptor protein by solid-phase filtration assay and Western blotting identified the receptor in endothelial cells and in granuloma (positive control) macrophages, but not in either CF-treated or untreated SMC. In addition, studies with both glutaraldehyde-fixed cells and CF bound to culture dishes indicated that Ac-LDL avidly binds to CF. Further, ultrastructural studies using colloidal gold-conjugated Ac-LDL showed Ac-LDL preferentially binding to CF aggregates on the cell surface. Thus, these studies indicate that treatment of cells with CF induces an endocytic process which, although remarkably similar to the scavenger pathway, is mediated by Ac-LDL binding to membrane-associated CF. These observations have implications in terms of mechanisms that might regulate the endocytosis of modified low-density lipoproteins.

UR - http://www.scopus.com/inward/record.url?scp=0023882880&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0023882880&partnerID=8YFLogxK

U2 - 10.1016/0014-4800(88)90072-X

DO - 10.1016/0014-4800(88)90072-X

M3 - Article

C2 - 3371460

AN - SCOPUS:0023882880

VL - 48

SP - 373

EP - 390

JO - Experimental and Molecular Pathology

JF - Experimental and Molecular Pathology

SN - 0014-4800

IS - 3

ER -