Prothrombin kringle-2 activates cultured rat brain microglia.
Microglia, the major immune effector cells in the CNS, become activated when the brain suffers injury. In this study, we observed that prothrombin, a zymogen of thrombin, induced NO release and mRNA expression of inducible NO synthase, IL-1beta, and TNF-alpha in rat brain microglia. The effect of prothrombin was independent of the protease activity of thrombin since hirudin, a specific inhibitor of thrombin, did not inhibit prothrombin-induced NO release. Furthermore, factor Xa enhanced the effect of prothrombin on microglial NO release. Kringle-2, a domain of prothrombin distinct from thrombin, mimicked the effect of prothrombin in inducing NO release and mRNA expression of inducible NO synthase, IL-1beta, and TNF-alpha. Prothrombin and kringle-2 both triggered the same intracellular signaling pathways. They both activated mitogen-activated protein kinases and NF-kappaB in a similar pattern. NO release stimulated by either was similarly reduced by inhibitors of the extracellular signal-regulated kinase pathway (PD98059), p38 (SB203580), NF-kappaB (N-acetylcysteine), protein kinase C (Go6976, bisindolylmaleimide, and Ro31-8220), and phospholipase C (D609 and U73122). These results suggest that prothrombin can activate microglia, and that, in addition to thrombin, kringle-2 is a domain of prothrombin independently capable of activating microglia.
Ryu
Jooyoung
J
Department of Pharmacology, Neuroscience Graduate Program, and Brain Disease Research Center, Ajou University School of Medicine, Suwon, Korea.
Min
Kyoung-Jin
KJ
Rhim
Tai Youn
TY
Kim
Tae Hyong
TH
Pyo
Hankyoung
H
Jin
Byungkwan
B
Kim
Seung-Up
SU
Jou
Ilo
I
Kim
Soung Soo
SS
Joe
Eun-Hye
EH
D000818:Animals; D001921:Brain / Q000187:drug effects* / Q000378:metabolism; D002478:Cells, Cultured; D004789:Enzyme Activation; D015951:Factor Xa / Q000494:pharmacology; D007375:Interleukin-1 / Q000235:genetics; D018082:Kringles / Q000502:physiology*; D017628:Microglia / Q000187:drug effects* / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D009569:Nitric Oxide / Q000096:biosynthesis; D019001:Nitric Oxide Synthase / Q000235:genetics; D052247:Nitric Oxide Synthase Type II; D011493:Protein Kinase C / Q000502:physiology; D011516:Prothrombin / Q000494:pharmacology*; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics; D010738:Type C Phospholipases / Q000502:physiology
D007375:Interleukin-1; D016328:NF-kappa B; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D009569:Nitric Oxide; D011516:Prothrombin; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496318:Nos2 protein, rat; D011493:Protein Kinase C; D020928:Mitogen-Activated Protein Kinases; D010738:Type C Phospholipases; D015951:Factor Xa