TY - JOUR
T1 - Proteoglycans synthesized by arterial smooth muscle cells in the presence of transforming growth factor-β1 exhibit increased binding to LDLs
AU - Little, Peter J.
AU - Tannock, Lisa
AU - Olin, Katherine L.
AU - Chait, Alan
AU - Wight, Thomas N.
PY - 2002
Y1 - 2002
N2 - The "response-to-retention" hypothesis of atherogenesis states that atherogenic lipoproteins, such as low density lipoprotein (LDL), are retained in vessels by proteoglycans and undergo proatherosclerotic modifications. Transforming growth factor (TGF)-β1 has been identified in atherosclerotic vessels and has been shown to stimulate the synthesis of chondroitin sulfate- and dermatan sulfate-containing proteoglycans by arterial smooth muscle cells (ASMCs), but whether it promotes lipid retention has not been addressed. We investigated whether TGF-β1 modulates the biosynthesis of proteoglycans by ASMCs in a manner that promotes binding to LDL. Proteoglycans isolated from TGF-β1-treated ASMCs exhibited enhanced binding to native LDL compared with the binding of proteoglycans isolated from control cultures (Kd 18 μg/mL LDL versus 81 μg/mL LDL, respectively). The increase in proteoglycan-LDL binding caused by TGF-β1 could be attributed primarily to the glycosaminoglycan portion of the proteoglycans, since the glycosaminoglycan chains liberated from the core proteins of these proteoglycans synthesized in the presence of TGF-β1 exhibited increased LDL binding as well. Furthermore, glycosaminoglycan chains initiated on xyloside (an initiator of glycosaminoglycan synthesis) in the presence of TGF-β1 were longer and displayed enhanced binding to LDL compared with the LDL binding of xyloside-initiated glycosaminoglycan chains from control cultures. These results indicate that TGF-β1 promotes LDL-proteoglycan interaction primarily by its effects on the glycosaminoglycan synthetic machinery of the ASMCs. Therefore, this study supports a proatherogenic role for TGF-β1.
AB - The "response-to-retention" hypothesis of atherogenesis states that atherogenic lipoproteins, such as low density lipoprotein (LDL), are retained in vessels by proteoglycans and undergo proatherosclerotic modifications. Transforming growth factor (TGF)-β1 has been identified in atherosclerotic vessels and has been shown to stimulate the synthesis of chondroitin sulfate- and dermatan sulfate-containing proteoglycans by arterial smooth muscle cells (ASMCs), but whether it promotes lipid retention has not been addressed. We investigated whether TGF-β1 modulates the biosynthesis of proteoglycans by ASMCs in a manner that promotes binding to LDL. Proteoglycans isolated from TGF-β1-treated ASMCs exhibited enhanced binding to native LDL compared with the binding of proteoglycans isolated from control cultures (Kd 18 μg/mL LDL versus 81 μg/mL LDL, respectively). The increase in proteoglycan-LDL binding caused by TGF-β1 could be attributed primarily to the glycosaminoglycan portion of the proteoglycans, since the glycosaminoglycan chains liberated from the core proteins of these proteoglycans synthesized in the presence of TGF-β1 exhibited increased LDL binding as well. Furthermore, glycosaminoglycan chains initiated on xyloside (an initiator of glycosaminoglycan synthesis) in the presence of TGF-β1 were longer and displayed enhanced binding to LDL compared with the LDL binding of xyloside-initiated glycosaminoglycan chains from control cultures. These results indicate that TGF-β1 promotes LDL-proteoglycan interaction primarily by its effects on the glycosaminoglycan synthetic machinery of the ASMCs. Therefore, this study supports a proatherogenic role for TGF-β1.
KW - Glycosaminoglycans
KW - Lipoproteins
KW - Proteoglycans
KW - Smooth muscle cells
KW - Transforming growth factor-β1
UR - http://www.scopus.com/inward/record.url?scp=0036143394&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0036143394&partnerID=8YFLogxK
U2 - 10.1161/hq0102.101100
DO - 10.1161/hq0102.101100
M3 - Article
C2 - 11788461
AN - SCOPUS:0036143394
SN - 1079-5642
VL - 22
SP - 55
EP - 60
JO - Arteriosclerosis, Thrombosis, and Vascular Biology
JF - Arteriosclerosis, Thrombosis, and Vascular Biology
IS - 1
ER -