Actin filament reorganization is a key step in lung inflammation induced by systemic inflammatory response syndrome.
Acute lung injury (ALI) induced by systemic inflammatory response syndrome (SIRS) is characterized by deterioration in pulmonary function and leukocyte-associated lung inflammation. Actin fragment (F-actin) reorganization is required for leukocyte activation, adhesion, and transcription of inflammatory factors. We tested the hypothesis that F-actin plays a central role in SIRS-induced ALI. ALI was produced in a rat model with extracorporeal circulation. Cytochalasin B (CB) pretreatment to block F-actin reorganization improved oxygenation and reduced BAL inflammatory factors and pulmonary neutrophil sequestration, but did not reduce the adhesive molecules of blood leukocytes. We challenged blood neutrophils with TNF-α in vitro to explore the underlying mechanisms. Upon activation, neutrophils became polarized and formed a protrusive leading edge, with an aggregation of CD11b molecules. This effect could be blocked by CB, leading to reduced neutrophil adhesion. In addition, after LPS challenge, we observed F-actin reorganization and the up-regulation of inflammatory factors in pulmonary monocytes, which could also be blocked by CB pretreatment. F-actin reorganization initiates lung inflammation via increased blood neutrophil adhesion and migration, and by the production of inflammatory factors by pulmonary monocytes. Thus, blocking F-actin reorganization may potentially prevent and treat SIRS-induced ALI.
Department of Anesthesiology and Translational Neuroscience Center, West China Hospital, Sichuan University, 37 Wainan Guoxuexiang, Chengdu, Sichuan 610041, China. scudulei@gmail.com
Lei
L
Du
Jing
J
Zhou
Jie
J
Zhang
Min
M
Yan
Lina
L
Gong
Xinhao
X
Liu
Mi
M
Chen
Kaiyu
K
Tao
Nanfu
N
Luo
Jin
J
Liu
D008841:Actin Cytoskeleton / Q000187:drug effects / Q000378:metabolism*; D000199:Actins / Q000037:antagonists & inhibitors / Q000378:metabolism; D055371:Acute Lung Injury / Q000209:etiology / Q000276:immunology / Q000378:metabolism / Q000517:prevention & control; D000818:Animals; D001992:Bronchoalveolar Lavage Fluid; D039481:CD11b Antigen / Q000378:metabolism; D002448:Cell Adhesion; D002465:Cell Movement; D002478:Cells, Cultured; D018920:Coculture Techniques; D003571:Cytochalasin B / Q000494:pharmacology / Q000627:therapeutic use; D016207:Cytokines / Q000378:metabolism; D042783:Endothelial Cells / Q000473:pathology / Q000502:physiology; D018836:Inflammation Mediators / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology; D008168:Lung / Q000187:drug effects / Q000276:immunology / Q000473:pathology; D008297:Male; D009000:Monocytes / Q000187:drug effects / Q000378:metabolism; D020556:Neutrophil Infiltration; D009504:Neutrophils / Q000276:immunology / Q000378:metabolism / Q000502:physiology; D011014:Pneumonia / Q000209:etiology / Q000276:immunology / Q000378:metabolism* / Q000517:prevention & control; D021381:Protein Transport; D051381:Rats; D017207:Rats, Sprague-Dawley; D018746:Systemic Inflammatory Response Syndrome / Q000150:complications / Q000188:drug therapy / Q000276:immunology / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000502:physiology
D000199:Actins; D039481:CD11b Antigen; D016207:Cytokines; D018836:Inflammation Mediators; D008070:Lipopolysaccharides; D014409:Tumor Necrosis Factor-alpha; D003571:Cytochalasin B