Related Experiment Videos
Neutrophil emigration in the lungs, peritoneum, and skin does not require gelatinase B
T Betsuyaku1, J M Shipley, Z Liu
1Pulmonary and Critical Care Medicine, Department of Medicine, Barnes-Jewish Hospital at Washington University School of Medicine, St. Louis, Missouri 63110, USA.
Abstract:
Polymorphonuclear leukocytes (PMN) release gelatinase B in response to variable stimuli. Gelatinase B degrades basement membrane components in vitro, and inhibition of matrix metalloproteinase activity blunts PMN migration through a prototype basement membrane (Matrigel) and amnionic membranes. Accordingly, it has been speculated that gelatinase B is necessary for PMN emigration. To test this hypothesis we induced acute inflammation in the lungs, peritoneum, and skin in mice with a null mutation of the gelatinase B gene (gelatinase B-/-) and littermate controls (gelatinase B+/+). At 3, 6, 12, and 24 h after intratracheal instillation of LPS, the emigration of PMN in the lung, as determined by PMN in bronchoalveolar lavage fluid, was similar in gelatinase B-/- and gelatinase B+/+ mice. The number of PMN in the peritoneal cavity 4 h after thioglycollate-induced peritonitis was also comparable in gelatinase B-/- and gelatinase B+/+ mice. At 4 h after an intradermal injection of interleukin-8, numerous PMN were present extravascularly in the dermis in both gelatinase B-/- and gelatinase B+/+ mice and the myeloperoxidase activities of the skin at the injection sites were indistinguishable between the two types of mice. PMN from gelatinase B-/- mice migrated through Matrigel in response to zymosan-activated serum with the same efficiency as did PMN from gelatinase B+/+ mice. In vitro, gelatinase B-/- PMN killed Staphylococcus aureus and Klebsiella pneumoniae as effectively as did PMN from gelatinase B+/+ mice. These findings indicate that gelatinase B is not required for PMN emigration, and suggest that the antibacterial function of PMN is preserved despite gelatinase B deficiency.
Insights
Gelatinase B is not essential for polymorphonuclear leukocyte (PMN) emigration during inflammation. PMN function, including bacterial killing, remains intact in mice lacking gelatinase B.
Area of Science:
- Immunology
- Cell Biology
- Biochemistry
Background:
- Polymorphonuclear leukocytes (PMN) release gelatinase B, an enzyme that degrades basement membrane components.
- Gelatinase B's role in PMN emigration is speculated due to its matrix-degrading activity.
- Inhibition of matrix metalloproteinase activity impairs PMN migration in vitro.
Purpose of the Study:
- To investigate the necessity of gelatinase B for PMN emigration in vivo.
- To determine if gelatinase B deficiency affects PMN migration to inflammatory sites.
- To assess the impact of gelatinase B deficiency on PMN antibacterial functions.
Main Methods:
- Induction of acute inflammation in lungs, peritoneum, and skin of gelatinase B-deficient (gelatinase B-/-) and wild-type (gelatinase B+/+) mice.
- Quantification of PMN in bronchoalveolar lavage fluid, peritoneal cavity, and skin.
- Assessment of PMN migration through Matrigel in vitro.
- Evaluation of PMN killing of Staphylococcus aureus and Klebsiella pneumoniae.
Main Results:
- PMN emigration into the lungs, peritoneum, and skin was similar in gelatinase B-/- and gelatinase B+/+ mice.
- PMN migration through Matrigel in vitro was comparable between genotypes.
- Gelatinase B-deficient PMN exhibited normal bacterial killing capacity.
Conclusions:
- Gelatinase B is not required for PMN emigration to inflammatory sites.
- PMN antibacterial functions are preserved in the absence of gelatinase B.
- These findings challenge the necessity of gelatinase B for PMN extravasation and host defense.