TY  - JOUR
A1  - Elgheznawy, Amro
A1  - Öftering, Patricia
A1  - Englert, Maximilian
A1  - Mott, Kristina
A1  - Kaiser, Friederike
A1  - Kusch, Charly
A1  - Gbureck, Uwe
A1  - Bösl, Michael R.
A1  - Schulze, Harald
A1  - Nieswandt, Bernhard
A1  - Vögtle, Timo
A1  - Hermanns, Heike M.
T1  - Loss of zinc transporters ZIP1 and ZIP3 augments platelet reactivity in response to thrombin and accelerates thrombus formation in vivo
JF  - Frontiers in Immunology
N2  - Zinc (Zn2+) is considered as important mediator of immune cell function, thrombosis and haemostasis. However, our understanding of the transport mechanisms that regulate Zn2+ homeostasis in platelets is limited. Zn2+ transporters, ZIPs and ZnTs, are widely expressed in eukaryotic cells. Using mice globally lacking ZIP1 and ZIP3 (ZIP1/3 DKO), our aim was to explore the potential role of these Zn2+ transporters in maintaining platelet Zn2+ homeostasis and in the regulation of platelet function. While ICP-MS measurements indicated unaltered overall Zn2+ concentrations in platelets of ZIP1/3 DKO mice, we observed a significantly increased content of FluoZin3-stainable free Zn2+, which, however, appears to be released less efficiently upon thrombin-stimulated platelet activation. On the functional level, ZIP1/3 DKO platelets exhibited a hyperactive response towards threshold concentrations of G protein-coupled receptor (GPCR) agonists, while immunoreceptor tyrosine-based activation motif (ITAM)-coupled receptor agonist signalling was unaffected. This resulted in enhanced platelet aggregation towards thrombin, bigger thrombus volume under flow ex vivo and faster in vivo thrombus formation in ZIP1/3 DKO mice. Molecularly, augmented GPCR responses were accompanied by enhanced Ca2+ and PKC, CamKII and ERK1/2 signalling. The current study thereby identifies ZIP1 and ZIP3 as important regulators for the maintenance of platelet Zn2+ homeostasis and function.
KW  - platelets
KW  - zinc
KW  - ZIP
KW  - thrombin
KW  - signaling
KW  - thrombosis
Y1  - 2023
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-320154
VL  - 14
ER  - 
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  -