Integrin-dependent neutrophil migration in the injured mouse cornea.
As an early responder to an inflammatory stimulus, neutrophils (PMNs) must exit the vasculature and migrate through the extravascular tissue to the site of insult, which is often remote from the point of extravasation. Following a central epithelial corneal abrasion, PMNs recruited from the peripheral limbal vasculature migrate into the avascular corneal stroma. In vitro studies suggest PMN locomotion over 2-D surfaces is dependent on integrin binding while migration within 3-D matrices can be integrin-independent. Electron micrographs of injured mouse corneas show migrating PMNs make extensive surface contact not only with collagen fibrils in the extracellular matrix (ECM), but also keratocytes. Evidence supporting involvement of integrins in corneal inflammation has prompted research and development of integrin blocking agents for use as anti-inflammatory therapies. However, the role of integrin binding (cell-cell; cell-ECM) during stromal migration in the inflamed cornea has previously not been clearly defined. In this study in vivo time lapse imaging sequences provided the means to quantify cell motility while observing PMN interactions with keratocytes and other stromal components in the living eye. The relative contribution of β1, β2 and β3 integrins to PMN locomotion in the inflamed mouse cornea was investigated using blocking antibodies against the respective integrins. Of the 3 integrin families (β1, β2 and β3) investigated for their potential role in PMN migration, only β1 antibody blockade produced a significant, but partial, reduction in PMN motility. The preferential migration of PMNs along the keratocyte network was not affected by integrin blockade. Hence, the dominant mechanism for PMN motility within the corneal stroma appears to be integrin-independent as does the restriction of PMN migration paths to the keratocyte network.
College of Optometry, University of Houston, Houston, TX, USA. Electronic address: shanlon@optometry.uh.edu.
Samuel D
SD
Hanlon
Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA.
C Wayne
CW
Smith
College of Optometry, University of Houston, Houston, TX, USA.
Marika N
MN
Sauter
College of Optometry, University of Houston, Houston, TX, USA; Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA.
Alan R
AR
Burns
D000818:Animals; D019138:Antibodies, Blocking; D018821:CD18 Antigens / Q000502:physiology; D002634:Chemotaxis, Leukocyte / Q000502:physiology*; D065306:Corneal Injuries; D060527:Corneal Keratocytes / Q000378:metabolism; D003319:Corneal Stroma / Q000166:cytology; D005131:Eye Injuries / Q000378:metabolism* / Q000503:physiopathology; D005260:Female; D019012:Integrin beta1 / Q000502:physiology; D039661:Integrin beta3 / Q000502:physiology; D016023:Integrins / Q000502:physiology*; D007634:Keratitis / Q000378:metabolism / Q000503:physiopathology; D051379:Mice; D008810:Mice, Inbred C57BL; D018613:Microscopy, Confocal; D009504:Neutrophils / Q000502:physiology*; D014949:Wounds, Nonpenetrating / Q000378:metabolism* / Q000503:physiopathology
D019138:Antibodies, Blocking; D018821:CD18 Antigens; D019012:Integrin beta1; D039661:Integrin beta3; D016023:Integrins
cornea; inflammation; integrin; keratocytes; migration; neutrophil