Species-specific anticoagulant and mitogenic activities of murine protein S.
BACKGROUND
The protein C pathway down-regulates thrombin generation and promotes cytoprotection during inflammation and stress. In preclinical studies using models of murine injury (e.g., sepsis and ischemic stroke), murine protein S may be required because of restrictive species specificity.


METHODS
We prepared and characterized recombinant murine protein S using novel coagulation assays, immunoassays, and cell proliferation assays.


RESULTS
Purified murine protein S had good anticoagulant co-factor activity for murine activated protein C, but not for human activated protein C, in mouse or rat plasma. In human plasma, murine protein S was a poor co-factor for murine activated protein C and had no anticoagulant effect with human activated protein C, suggesting protein S species specificity for factor V in addition to activated protein C. We estimated that mouse plasma contains 22+/-1 microg/mL protein S and developed assays to measure activated protein C co-factor activity of the protein S in murine plasma. Activated protein C-independent anticoagulant activity of murine protein S was demonstrable and quantifiable in mouse plasma, and this activity was enhanced by exogenous murine protein S. Murine protein S promoted the proliferation of mouse and human smooth muscle cells. The potency of murine protein S was higher for mouse cells than for human cells and similarly, human protein S was more potent for human cells than for mouse cells.


CONCLUSIONS
The spectrum of bioactivities of recombinant murine protein S with mouse plasma and smooth muscle cells is similar to that of human protein S. However, in vitro and in vivo studies of the protein C pathway in murine disease models are more appropriately performed using murine protein S. This study extends previous observations regarding the remarkable species specificity of protein S to the mouse.
Fernández
José A
JA
Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA.
Heeb
Mary J
MJ
Xu
Xiao
X
Singh
Itender
I
Zlokovic
Berislav V
BV
Griffin
John H
JH
D000818:Animals; D000925:Anticoagulants / Q000494:pharmacology*; D001777:Blood Coagulation / Q000187:drug effects; D002417:Cattle; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D006207:Half-Life; D006801:Humans; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008813:Mice, Inbred ICR; D008934:Mitogens / Q000494:pharmacology*; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects; D032389:Myocytes, Smooth Muscle / Q000166:cytology / Q000187:drug effects; D010314:Partial Thromboplastin Time; D011486:Protein C / Q000378:metabolism / Q000494:pharmacology; D017293:Protein S / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology*; D051381:Rats; D011994:Recombinant Proteins / Q000378:metabolism / Q000494:pharmacology; D013045:Species Specificity
D000925:Anticoagulants; D008934:Mitogens; D011486:Protein C; D017293:Protein S; D011994:Recombinant Proteins