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  - 
TY  - JOUR
A1  - Liu, Fengming
A1  - Han, Kun
A1  - Blair, Robert
A1  - Kenst, Kornelia
A1  - Qin, Zhongnan
A1  - Upcin, Berin
A1  - Wörsdörfer, Philipp
A1  - Midkiff, Cecily C.
A1  - Mudd, Joseph
A1  - Belyaeva, Elizaveta
A1  - Milligan, Nicholas S.
A1  - Rorison, Tyler D.
A1  - Wagner, Nicole
A1  - Bodem, Jochen
A1  - Dölken, Lars
A1  - Aktas, Bertal H.
A1  - Vander Heide, Richard S.
A1  - Yin, Xiao-Ming
A1  - Kolls, Jay K.
A1  - Roy, Chad J.
A1  - Rappaport, Jay
A1  - Ergün, Süleyman
A1  - Qin, Xuebin
T1  - SARS-CoV-2 Infects Endothelial Cells In Vivo and In Vitro
JF  - Frontiers in Cellular and Infection Microbiology
N2  - SARS-CoV-2 infection can cause fatal inflammatory lung pathology, including thrombosis and increased pulmonary vascular permeability leading to edema and hemorrhage. In addition to the lung, cytokine storm-induced inflammatory cascade also affects other organs. SARS-CoV-2 infection-related vascular inflammation is characterized by endotheliopathy in the lung and other organs. Whether SARS-CoV-2 causes endotheliopathy by directly infecting endothelial cells is not known and is the focus of the present study. We observed 1) the co-localization of SARS-CoV-2 with the endothelial cell marker CD31 in the lungs of SARS-CoV-2-infected mice expressing hACE2 in the lung by intranasal delivery of adenovirus 5-hACE2 (Ad5-hACE2 mice) and non-human primates at both the protein and RNA levels, and 2) SARS-CoV-2 proteins in endothelial cells by immunogold labeling and electron microscopic analysis. We also detected the co-localization of SARS-CoV-2 with CD31 in autopsied lung tissue obtained from patients who died from severe COVID-19. Comparative analysis of RNA sequencing data of the lungs of infected Ad5-hACE2 and Ad5-empty (control) mice revealed upregulated KRAS signaling pathway, a well-known pathway for cellular activation and dysfunction. Further, we showed that SARS-CoV-2 directly infects mature mouse aortic endothelial cells (AoECs) that were activated by performing an aortic sprouting assay prior to exposure to SARS-CoV-2. This was demonstrated by co-localization of SARS-CoV-2 and CD34 by immunostaining and detection of viral particles in electron microscopic studies. Moreover, the activated AoECs became positive for ACE-2 but not quiescent AoECs. Together, our results indicate that in addition to pneumocytes, SARS-CoV-2 also directly infects mature vascular endothelial cells in vivo and ex vivo, which may contribute to cardiovascular complications in SARS-CoV-2 infection, including multipleorgan failure.
KW  - endothelial cell infection
KW  - animal models
KW  - SARS-CoV-2
KW  - aorta ring
KW  - hACE2
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-241948
SN  - 2235-2988
VL  - 11
ER  -