Critical role of FcR gamma-chain, LAT, PLCgamma2 and thrombin in arteriolar thrombus formation upon mild, laser-induced endothelial injury in vivo.
OBJECTIVE
The role of collagen receptor complex GPVI-FcR gamma-chain, PLCgamma2 and LAT in laser-induced thrombosis is unclear. Controversy surrounds whether collagen is exposed in this model or whether thrombosis is dependent on thrombin. This study hypothesized that collagen exposure plays a critical role in thrombus formation in this model, which was tested by investigating contributions of FcR gamma-chain, LAT, PLCgamma2 and thrombin.


METHODS
Thrombi were monitored using intravital microscopy in anesthetized wild-type and FcR gamma-chain, LAT and PLCgamma2 knockout mice. Hirudin (thrombin inhibitor) was administered to wild-type and FcR gamma-chain knockout mice.


RESULTS
Significantly reduced thrombus formation was observed in FcR gamma-chain and PLCgamma2 knockouts with a greater decrease observed in LAT knockouts. Dramatic reduction was observed in wild-types treated with hirudin, with abolished thrombus formation only observed in FcR gamma-chain knockouts treated with hirudin.


CONCLUSIONS
GPVI-FcR gamma-chain, LAT and PLCgamma2 are essential for thrombus generation and stability in this laser-induced model of injury. More importantly, a greater role for LAT was identified, which may reflect a role for it downstream of a second matrix protein receptor. However, inhibition of platelet activation by matrix proteins and thrombin generation are both required to maximally prevent thrombus formation.
Kalia
Neena
N
Centre for Cardiovascular Sciences, Institute of Biomedical Research, The Medical School, University of Birmingham, Birmingham, United Kingdom. n.kalia@bham.ac.uk
Auger
Jocelyn M
JM
Atkinson
Ben
B
Watson
Steve P
SP
D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D003094:Collagen / Q000235:genetics / Q000378:metabolism; D004195:Disease Models, Animal; D004730:Endothelium, Vascular / Q000293:injuries* / Q000378:metabolism*; D007834:Lasers / Q000009:adverse effects*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D051966:Phospholipase C gamma / Q000235:genetics / Q000378:metabolism*; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D038981:Receptors, Collagen / Q000235:genetics / Q000378:metabolism; D017452:Receptors, IgG / Q000235:genetics / Q000378:metabolism*; D013917:Thrombin / Q000235:genetics / Q000378:metabolism; D013927:Thrombosis / Q000209:etiology / Q000235:genetics / Q000378:metabolism*
D048868:Adaptor Proteins, Signal Transducing; C491734:Lat protein, mouse; D008565:Membrane Proteins; D010750:Phosphoproteins; D038981:Receptors, Collagen; D017452:Receptors, IgG; D003094:Collagen; D051966:Phospholipase C gamma; D013917:Thrombin