Proteoglycan form of macrophage colony-stimulating factor binds low density lipoprotein.
We recently isolated a proteoglycan form of macrophage colony-stimulating factor (PG-M-CSF) that carries a chondroitin sulfate glycosaminoglycan chain. Here, we examined the interaction of PG-M-CSF with low density lipoprotein (LDL). When LDL preincubated with PG-M-CSF was fractionated by molecular size sieving chromatography, it was eluted earlier than untreated LDL. When LDL was preincubated with chondroitin sulfate-free 85-kD M-CSF instead of PG-M-CSF, the elution profile of LDL remained unchanged, indicating specific interaction between PG-M-CSF and LDL. The level of PG-M-CSF binding in the wells of a plastic microtitration plate precoated with LDL was significant, this binding being completely abolished by pretreatment of PG-M-CSF with chondroitinase AC, which degrades chondroitin sulfate. The addition of exogenous chondroitin sulfate or apolipoprotein B inhibited the binding of PG-M-CSF to LDL in a dose-dependent manner, indicating that the interaction between PG-M-CSF and LDL was mediated by the binding of the chondroitin sulfate chain of PG-M-CSF to LDL apolipoprotein B. PG-M-CSF was also demonstrated in the arterial wall, and there were increased amounts of PG-M-CSF in atherosclerotic lesions. The in vitro interaction between PG-M-CSF and LDL thus appears to have physiological significance.
Suzu
S
S
Biochemical Research Laboratory, Morinaga Milk Industry Co., Ltd., Kanagawa, Japan.
Inaba
T
T
Yanai
N
N
Kawashima
T
T
Yamada
N
N
Oka
T
T
Machinami
R
R
Ohtsuki
T
T
Kimura
F
F
Kondo
S
S
D001011:Aorta / Q000737:chemistry; D001055:Apolipoproteins B / Q000378:metabolism; D001161:Arteriosclerosis / Q000378:metabolism; D002809:Chondroitin Sulfates / Q000032:analysis / Q000097:blood / Q000378:metabolism*; D006801:Humans; D008077:Lipoproteins, LDL / Q000302:isolation & purification / Q000378:metabolism*; D016173:Macrophage Colony-Stimulating Factor / Q000032:analysis / Q000097:blood / Q000378:metabolism*; D011485:Protein Binding
D001055:Apolipoproteins B; D008077:Lipoproteins, LDL; C038142:chondroitin sulfate glycosaminoglycan; D016173:Macrophage Colony-Stimulating Factor; D002809:Chondroitin Sulfates