Involvement of heparanase in migration of microglial cells.
Heparanase, a matrix-degrading enzyme that cleaves heparan sulfate side chains from heparan sulfate proteoglycans (HSPGs), has been shown to facilitate cell invasion, migration, and extravasation of metastatic tumor cells or immune cells. In this study, the expression and functions of heparanase were investigated using rat primary cultured microglia, the resident macrophages in the brain. The microglia were found to express heparanase mRNA and protein. Microglia treated with lipopolysaccharide (LPS) were activated, expressed induced nitric oxide synthase and elevated the expression of heparanase. Heparanase has two molecular weights: a 65 kDa latent form and an active 50 kDa. Both forms were expressed by LPS-treated activated microglia; however, untreated microglia primarily expressed the latent form. Cell lysates from microglia actually degraded Matrigel containing HSPG. Heparanase was colocalized with the actin cytoskeleton in microglial leading edges or ruffled membranes. Microglia transmigrated through a Matrigel-coated pored membrane. This process was inhibited by SF-4, a specific heparanase inhibitor, in a concentration-dependent manner. Degraded HSPG was generated when microglia transmigrated through the coated membrane, and this was also inhibited by SF-4. The results suggest the involvement of heparanase in the migration or invasion of microglia or brain macrophages across basement membrane around brain vasculature.
Takahashi
Hisaaki
H
Department of Molecular and Cellular Physiology, Graduate School of Medicine, Ehime University, Toon, Ehime 791-0295, Japan. hisaaki@m.ehime-u.ac.jp
Matsumoto
Hiroaki
H
Smirkin
Anna
A
Itai
Tomohide
T
Nishimura
Yoshio
Y
Tanaka
Junya
J
D000818:Animals; D000831:Animals, Newborn; D015153:Blotting, Western; D002465:Cell Movement; D002478:Cells, Cultured; D003094:Collagen; D004338:Drug Combinations; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000494:pharmacology; D015870:Gene Expression / Q000187:drug effects; D005966:Glucuronidase / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D019812:Heparan Sulfate Proteoglycans / Q000378:metabolism; D007150:Immunohistochemistry; D007797:Laminin; D008070:Lipopolysaccharides / Q000494:pharmacology; D008297:Male; D017628:Microglia / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D015394:Molecular Structure; D019001:Nitric Oxide Synthase / Q000235:genetics / Q000378:metabolism; D010880:Piperidines / Q000737:chemistry / Q000494:pharmacology; D011509:Proteoglycans; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction; D000099175:Heparanase
D003094:Collagen; D004338:Drug Combinations; D004791:Enzyme Inhibitors; D005966:Glucuronidase; D019812:Heparan Sulfate Proteoglycans; D007797:Laminin; D008070:Lipopolysaccharides; D019001:Nitric Oxide Synthase; D010880:Piperidines; D011509:Proteoglycans; D012333:RNA, Messenger; D000099175:Heparanase; C086155:6-trifluoroacetamido-4,5-dihydroxy-3-piperidinecarboxylic acid; C059485:matrigel