Thrombin-induced activation of cultured rodent microglia.
Microglia are the resident immune cells of the CNS. Upon brain damage, these cells are rapidly activated and function as tissue macrophages. The first steps in this activation still remain unclear, but it is widely believed that substances released from damaged brain tissue trigger this process. In this article, we describe the effects of the blood coagulation factor thrombin on cultured rodent microglial cells. Thrombin induced a transient Ca(2+) increase in microglial cells, which persisted in Ca(2+)-free media. It was blocked by thapsigargin, indicating that thrombin caused a Ca(2+) release from internal stores. Preincubation with pertussis toxin did not alter the thrombin-induced [Ca(2+)](i) signal, whereas it was blocked by hirudin, a blocker of thrombin's proteolytic activity. Incubation with thrombin led to the production of nitric oxide and the release of the cytokines tumor necrosis factor-alpha, interleukin-6, interleukin-12, the chemokine KC, and the soluble tumor necrosis factor-alpha receptor II and had a significant proliferative effect. Our findings indicate that thrombin, a molecule that enters the brain at sites of injury, rapidly triggered microglial activation.
Möller
T
T
Department of Neurology, University of Washington, Seattle, Washington 98195, USA. moeller@u.washington.edu
Hanisch
U K
UK
Ransom
B R
BR
D000255:Adenosine Triphosphate / Q000378:metabolism / Q000494:pharmacology; D000818:Animals; D000991:Antithrombins / Q000494:pharmacology; D020013:Calcium Signaling / Q000187:drug effects; D000252:Calcium-Transporting ATPases / Q000037:antagonists & inhibitors; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D018925:Chemokines / Q000378:metabolism; D016207:Cytokines / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D019204:GTP-Binding Proteins / Q000037:antagonists & inhibitors; D006629:Hirudins / Q000494:pharmacology; D007424:Intracellular Fluid / Q000378:metabolism; D017628:Microglia / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism; D037342:Pertussis Toxin; D051381:Rats; D020318:Rats, Long-Evans; D015398:Signal Transduction / Q000187:drug effects; D019284:Thapsigargin / Q000494:pharmacology; D013917:Thrombin / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D000991:Antithrombins; D018925:Chemokines; D016207:Cytokines; D006629:Hirudins; D010566:Virulence Factors, Bordetella; D009569:Nitric Oxide; D019284:Thapsigargin; D000255:Adenosine Triphosphate; D037342:Pertussis Toxin; D013917:Thrombin; D019204:GTP-Binding Proteins; D000252:Calcium-Transporting ATPases