title: Calpain inhibition impairs TNF-alpha-mediated neutrophil adhesion, arrest and oxidative burst.
abstract: Proinflammatory cytokines, such as tumor necrosis factor alpha (TNF-alpha), are increased in many chronic inflammatory disorders, including rheumatoid arthritis, and contribute to recruitment of neutrophils into areas of inflammation. TNF-alpha induces a stop signal that promotes neutrophil firm adhesion and inhibits neutrophil polarization and chemotaxis. Calpain is a calcium-dependent protease that mediates cytoskeletal reorganization during cell migration. Here, we show that calpain inhibition impairs TNF-alpha-induced neutrophil firm adhesion to fibrinogen-coated surfaces and the formation of vinculin-containing focal complexes. Calpain inhibition induces random migration in TNF-alpha-stimulated cells and prevents the generation of reactive oxygen species, but does not alter TNF-alpha-mediated activation of p38 MAPK and ERK MAPK. These findings suggest that the TNF-alpha-induced neutrophil arrest requires the activity of calpain independent of p38 MAPK and ERK signaling seen after TNF-alpha stimulation. Together, our data suggest that therapeutic inhibition of calpain may be beneficial for limiting TNF-alpha-induced inflammatory responses.
authors.affiliation: Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, WI, USA.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Wiemer
authors.forename: Mary A
authors.initials: MA
authors.lastname: Lokuta
authors.forename: Jill C
authors.initials: JC
authors.lastname: Surfus
authors.forename: Sarah A
authors.initials: SA
authors.lastname: Wernimont
authors.forename: Anna
authors.initials: A
authors.lastname: Huttenlocher
mesh_terms: D002154:Calpain / Q000037:antagonists & inhibitors* / Q000378:metabolism; D002448:Cell Adhesion / Q000187:drug effects; D002465:Cell Movement / Q000187:drug effects; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology*; D003599:Cytoskeleton / Q000187:drug effects / Q000201:enzymology; D004789:Enzyme Activation / Q000187:drug effects; D006801:Humans; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009504:Neutrophils / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology*; D016897:Respiratory Burst / Q000187:drug effects*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
chemical_list: D015853:Cysteine Proteinase Inhibitors; D014409:Tumor Necrosis Factor-alpha; D020928:Mitogen-Activated Protein Kinases; D002154:Calpain