Table 2.

The Vertebrate Heparan Sulfate Proteoglycans

Proteoglycan	Core protein (kD)	Number and type of GAG chains	Tissue distribution	Proposed functions in CVD	Human disease associations
Secreted Proteoglycans
Perlecan	400	1–3 HS, 0–2 CS	Basement membranes, other ECM, cartilage	Lipoprotein retention in the vessel wall	Rare mutations causing severe skeletal malformations
Agrin	200	1–3 HS	Basement membranes, brain and neuromuscular junctions	Unknown
Collagen type XVIII	147	2–3 HS	Basement membranes, longest isoform more widespread	LPL processing	Mutations give rise to Knobloch syndrome, with multiple ocular, neural tube closure defects and hypertriglyceridemia
Membrane-bound Proteoglycans
Syndecans 1–4	31–45	1–3 HS, 0–2 CS	Most nucleated cells	Hepatic TRL clearance; uptake of sPLA2 modified LDL in macrophages; attenuation of macrophage and endothelial inflammation	Dysregulation in several cancers, e.g. myeloma, mammary carcinoma
Betaglycan	110	0–1 HS, 0–1 CS	Fibroblasts	Unknown	Tumor suppressor; commonly lost in ovarian cancer
Glypicans 1–6	~60	1–3 HS	Epithelial and mesenchymal cells, brain	Unknown	Simpson-Golabi-Behmel overgrowth syndrome,hepatocellular carcinoma progression (GPC3)
Intracellular Granule Proteoglycans
Serglycin	10–19	10–15 heparin/CS	Mast cells, other leukocytes, endothelial cells	Unknown	Inflammation, cancer progression

HS, heparan sulfate; CS, chondroitin sulfate; DS, dermatan sulfate; CD44v3, NRP1, APLP2, CD47 are not listed because there is no genetic evidence that supports their role in atherogenesis.