Effect of antithrombin III on neutrophil deformability.
As the spherical diameter of pulmonary capillaries is smaller than that of neutrophils, increased neutrophil stiffness or conversely, decreased neutrophil deformability is a key step in the initial sequestration of neutrophils within the lungs during inflammatory processes. Antithrombin III (AT) is known to exert a therapeutic effect against disseminated intravascular coagulation, and accumulating evidence suggests that AT also has anti-inflammatory properties. The mechanisms of its anti-inflammatory effects remain unclear, but in a rat endotoxin model, AT apparently inhibited neutrophil sequestration in the lung. In the present in vitro study, therefore, we examined the effect of AT on the deformability of human neutrophils and correlated those findings with their F-actin content. Isolated human neutrophils were stimulated with formyl-Met-Leu-Phe (1 muM, 2 min) in the presence or absence of the alpha, beta, or low heparin-affinity isoforms of AT (1 IU/ml, 20 min), and deformability was evaluated using a filter assay system. Neutrophils were also stained with fluorescein isothiocyanate-phalloidin and subjected to a fluorescein-activated cell sorter scan to assess F-actin content. The results showed that pretreatment with any of the three AT isoforms similarly inhibited the decreased neutrophil deformability and increased F-actin content of stimulated cells. Notably, heparinase had no effect on deformability or F-actin content in the presence or absence of AT, which was somewhat unexpected, as heparin sulfate proteoglycans likely function as AT receptors. These findings suggested that AT inhibits the increase in neutrophil stiffness seen during inflammatory processes by inhibiting actin polymerization via a heparin-independent pathway.
Division of Thoracic Surgery, Akita University School of Medicine, 1-1-1 Hondo, Akita City 010-8543, Japan. hsaito@doc.med.akita-u.ac.jp
Hajime
H
Saito
Yoshihiro
Y
Minamiya
Uwe
U
Kalina
Satoshi
S
Saito
Jun-Ichi
J
Ogawa
D000199:Actins / Q000032:analysis / Q000187:drug effects / Q000378:metabolism; D000990:Antithrombin III / Q000737:chemistry / Q000494:pharmacology*; D019763:Heparin Lyase / Q000494:pharmacology; D006801:Humans; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D009504:Neutrophils / Q000166:cytology* / Q000187:drug effects* / Q000378:metabolism; D010590:Phalloidine / Q000031:analogs & derivatives / Q000737:chemistry; D012016:Reference Values; D013194:Staining and Labeling
D000199:Actins; C037191:fluorescein isothiocyanate-phalloidin; D010590:Phalloidine; D009240:N-Formylmethionine Leucyl-Phenylalanine; D000990:Antithrombin III; D019763:Heparin Lyase