TY  - JOUR
A1  - Regn, Michael
A1  - Laggerbauer, Bernhard
A1  - Jentzsch, Claudia
A1  - Ramanujam, Deepak
A1  - Ahles, Andrea
A1  - Sichler, Sonja
A1  - Calzada-Wack, Julia
A1  - Koenen, Rory R.
A1  - Braun, Attila
A1  - Nieswandt, Bernhard
A1  - Engelhardt, Stefan
T1  - Peptidase inhibitor 16 is a membrane-tethered regulator of chemerin processing in the myocardium
JF  - Journal of Molecular and Cellular Cardiology
N2  - A key response of the myocardium to stress is the secretion of factors with paracrine or endocrine function. Intriguing in this respect is peptidase inhibitor 16 (PI16), a member of the CAP family of proteins which we found to be highly upregulated in cardiac disease. Up to this point, the mechanism of action and physiological function of PI16 remained elusive. Here, we show that PI16 is predominantly expressed by cardiac fibroblasts, which expose PI16 to the interstitium via a glycophosphatidylinositol (-GPI) membrane anchor. Based on a reported genetic association of PI16 and plasma levels of the chemokine chemerin, we investigated whether PI16 regulates post-translational processing of its precursor pro-chemerin. PI16-deficient mice were engineered and found to generate higher levels of processed chemerin than wildtype mice. Purified recombinant PI16 efficiently inhibited cathepsin K, a chemerin-activating protease, in vitro. Moreover, we show that conditioned medium from PI16-overexpressing cells impaired the activation of pro-chemerin. Together, our data indicate that PI16 suppresses chemerin activation in the myocardium and suggest that this circuit may be part of the cardiac stress response.
KW  - Cells
KW  - Activation
KW  - Purification
KW  - Protein
KW  - Peptidase inhibitor 16 (PI16)
KW  - Identification
KW  - Inflammation
KW  - Adipokine
KW  - Metabolism
KW  - Heart
KW  - Mice
KW  - Chemerin
KW  - RARRES2
KW  - TIG2
KW  - Protease inhibition
KW  - Chemerin processing
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-187039
VL  - 99
ER  - 
TY  - JOUR
A1  - Hopp, Sarah
A1  - Albert-Weissenberger, Christiane
A1  - Mencl, Stine
A1  - Bieber, Michael
A1  - Schuhmann, Michael K.
A1  - Stetter, Christian
A1  - Nieswandt, Bernhard
A1  - Schmidt, Peter M.
A1  - Monoranu, Camelia-Maria
A1  - Alafuzoff, Irina
A1  - Marklund, Niklas
A1  - Nolte, Marc W.
A1  - Sirén, Anna-Leena
A1  - Kleinschnitz, Christoph
T1  - Targeting coagulation factor XII as a novel therapeutic option in brain trauma
JF  - Annals of Neurology
N2  - Objective: 
Traumatic brain injury is a major global public health problem for which specific therapeutic interventions are lacking. There is, therefore, a pressing need to identify innovative pathomechanism-based effective therapies for this condition. Thrombus formation in the cerebral microcirculation has been proposed to contribute to secondary brain damage by causing pericontusional ischemia, but previous studies have failed to harness this finding for therapeutic use. The aim of this study was to obtain preclinical evidence supporting the hypothesis that targeting factor XII prevents thrombus formation and has a beneficial effect on outcome after traumatic brain injury. 

Methods: 
We investigated the impact of genetic deficiency of factor XII and acute inhibition of activated factor XII with a single bolus injection of recombinant human albumin-fused infestin-4 (rHA-Infestin-4) on trauma-induced microvascular thrombus formation and the subsequent outcome in 2 mouse models of traumatic brain injury. 

Results: 
Our study showed that both genetic deficiency of factor XII and an inhibition of activated factor XII in mice minimize trauma-induced microvascular thrombus formation and improve outcome, as reflected by better motor function, reduced brain lesion volume, and diminished neurodegeneration. Administration of human factor XII in factor XII-deficient mice fully restored injury-induced microvascular thrombus formation and brain damage. 

Interpretation: 
The robust protective effect of rHA-Infestin-4 points to a novel treatment option that can decrease ischemic injury after traumatic brain injury without increasing bleeding tendencies.
KW  - Molecular-weight heparin
KW  - Thrombus formation
KW  - Cerebral-ischemia
KW  - in-vivo
KW  - Intravascular coagulation
KW  - Hemodynamic depression
KW  - Head-injury
KW  - Rats
KW  - Model
KW  - Mice
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-188800
VL  - 79
IS  - 6
ER  -