TY  - JOUR
A1  - Rosa, Annabelle
A1  - Butt, Elke
A1  - Hopper, Christopher P.
A1  - Loroch, Stefan
A1  - Bender, Markus
A1  - Schulze, Harald
A1  - Sickmann, Albert
A1  - Vorlova, Sandra
A1  - Seizer, Peter
A1  - Heinzmann, David
A1  - Zernecke, Alma
T1  - Cyclophilin a is not acetylated at lysine-82 and lysine-125 in resting and stimulated platelets
JF  - International Journal of Molecular Sciences
N2  - Cyclophilin A (CyPA) is widely expressed by all prokaryotic and eukaryotic cells. Upon activation, CyPA can be released into the extracellular space to engage in a variety of functions, such as interaction with the CD147 receptor, that contribute to the pathogenesis of cardiovascular diseases. CyPA was recently found to undergo acetylation at K82 and K125, two lysine residues conserved in most species, and these modifications are required for secretion of CyPA in response to cell activation in vascular smooth muscle cells. Herein we addressed whether acetylation at these sites is also required for the release of CyPA from platelets based on the potential for local delivery of CyPA that may exacerbate cardiovascular disease events. Western blot analyses confirmed the presence of CyPA in human and mouse platelets. Thrombin stimulation resulted in CyPA release from platelets; however, no acetylation was observed—neither in cell lysates nor in supernatants of both untreated and activated platelets, nor after immunoprecipitation of CyPA from platelets. Shotgun proteomics detected two CyPA peptide precursors in the recombinant protein, acetylated at K28, but again, no acetylation was found in CyPA derived from resting or stimulated platelets. Our findings suggest that acetylation of CyPA is not a major protein modification in platelets and that CyPA acetylation is not required for its secretion from platelets.
KW  - Cyclophilin A
KW  - acetylation
KW  - platelets
KW  - CD147
KW  - EMMPRIN
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-284011
SN  - 1422-0067
VL  - 23
IS  - 3
ER  - 
TY  - JOUR
A1  - Beck, Sarah
A1  - Stegner, David
A1  - Loroch, Stefan
A1  - Baig, Ayesha A.
A1  - Göb, Vanessa
A1  - Schumbutzki, Cornelia
A1  - Eilers, Eva
A1  - Sickmann, Albert
A1  - May, Frauke
A1  - Nolte, Marc W.
A1  - Panousis, Con
A1  - Nieswandt, Bernhard
T1  - Generation of a humanized FXII knock-in mouse-A powerful model system to test novel anti-thrombotic agents
JF  - Journal of Thrombosis and Haemostasis
N2  - Background
Effective inhibition of thrombosis without generating bleeding risks is a major challenge in medicine. Accumulating evidence suggests that this can be achieved by inhibition of coagulation factor XII (FXII), as either its knock-out or inhibition in animal models efficiently reduced thrombosis without affecting normal hemostasis. Based on these findings, highly specific inhibitors for human FXII(a) are under development. However, currently, in vivo studies on their efficacy and safety are impeded by the lack of an optimized animal model expressing the specific target, that is, human FXII.

Objective
The primary objective of this study is to develop and functionally characterize a humanized FXII mouse model.

Methods
A humanized FXII mouse model was generated by replacing the murine with the human F12 gene (genetic knock-in) and tested it in in vitro coagulation assays and in in vivo thrombosis models.

Results
These hF12\(^{KI}\) mice were indistinguishable from wild-type mice in all tested assays of coagulation and platelet function in vitro and in vivo, except for reduced expression levels of hFXII compared to human plasma. Targeting FXII by the anti-human FXIIa antibody 3F7 increased activated partial thromboplastin time dose-dependently and protected hF12\(^{KI}\) mice in an arterial thrombosis model without affecting bleeding times.

Conclusion
These data establish the newly generated hF12\(^{KI}\) mouse as a powerful and unique model system for in vivo studies on anti-FXII(a) biologics, supporting the development of efficient and safe human FXII(a) inhibitors.
KW  - hemostasis,
KW  - blood coagulation
KW  - factor XII
KW  - animal models
KW  - thrombosis
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-259567
VL  - 19
IS  - 11
ER  -