@article{GotruvanGeffenNagyetal.2019,
  author    = {Gotru, Sanjeev Kiran and van Geffen, Johanna P. and Nagy, Magdolna and Mammadova-Bach, Elmina and Eilenberger, Julia and Volz, Julia and Manukjan, Georgi and Schulze, Harald and Wagner, Leonard and Eber, Stefan and Schambeck, Christian and Deppermann, Carsten and Brouns, Sanne and Nurden, Paquita and Greinacher, Andreas and Sachs, Ulrich and Nieswandt, Bernhard and Hermanns, Heike M. and Heemskerk, Johan W. M. and Braun, Attila},
  title     = {Defective Zn2+ homeostasis in mouse and human platelets with α- and δ-storage pool diseases},
  series = {Scientific Reports},
  volume    = {9},
  journal   = {Scientific Reports},
  doi       = {10.1038/s41598-019-44751-w},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-227455},
  year      = {2019},
  abstract  = {Zinc (Zn2+) can modulate platelet and coagulation activation pathways, including fibrin formation. Here, we studied the (patho)physiological consequences of abnormal platelet Zn2+ storage and release. To visualize Zn2+ storage in human and mouse platelets, the Zn2+ specific fluorescent dye FluoZin3 was used. In resting platelets, the dye transiently accumulated into distinct cytosolic puncta, which were lost upon platelet activation. Platelets isolated from Unc13d-/- mice, characterized by combined defects of α/δ granular release, showed a markedly impaired Zn2+ release upon activation. Platelets from Nbeal2-/- mice mimicking Gray platelet syndrome (GPS), characterized by primarily loss of the α-granule content, had strongly reduced Zn2+ levels, which was also confirmed in primary megakaryocytes. In human platelets isolated from patients with GPS, Hermansky-Pudlak Syndrome (HPS) and Storage Pool Disease (SPD) altered Zn2+ homeostasis was detected. In turbidity and flow based assays, platelet-dependent fibrin formation was impaired in both Nbeal2-/- and Unc13d-/- mice, and the impairment could be partially restored by extracellular Zn2+. Altogether, we conclude that the release of ionic Zn2+ store from secretory granules upon platelet activation contributes to the procoagulant role of Zn2+ in platelet-dependent fibrin formation.},
  language  = {en}
}
@article{ThiemHesbacherKneitzetal.2019,
  author    = {Thiem, Alexander and Hesbacher, Sonja and Kneitz, Hermann and di Primio, Teresa and Heppt, Markus V. and Hermanns, Heike M. and Goebeler, Matthias and Meierjohann, Svenja and Houben, Roland and Schrama, David},
  title     = {IFN-gamma-induced PD-L1 expression in melanoma depends on p53 expression},
  series = {Journal of Experimental \& Clinical Cancer Research},
  volume    = {38},
  journal   = {Journal of Experimental \& Clinical Cancer Research},
  doi       = {10.1186/s13046-019-1403-9},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-201016},
  pages     = {397},
  year      = {2019},
  abstract  = {Background Immune checkpoint inhibition and in particular anti-PD-1 immunotherapy have revolutionized the treatment of advanced melanoma. In this regard, higher tumoral PD-L1 protein (gene name: CD274) expression is associated with better clinical response and increased survival to anti-PD-1 therapy. Moreover, there is increasing evidence that tumor suppressor proteins are involved in immune regulation and are capable of modulating the expression of immune checkpoint proteins. Here, we determined the role of p53 protein (gene name: TP53) in the regulation of PD-L1 expression in melanoma. Methods We analyzed publicly available mRNA and protein expression data from the cancer genome/proteome atlas and performed immunohistochemistry on tumors with known TP53 status. Constitutive and IFN-ɣ-induced PD-L1 expression upon p53 knockdown in wildtype, TP53-mutated or JAK2-overexpressing melanoma cells or in cells, in which p53 was rendered transcriptionally inactive by CRISPR/Cas9, was determined by immunoblot or flow cytometry. Similarly, PD-L1 expression was investigated after overexpression of a transcriptionally-impaired p53 (L22Q, W23S) in TP53-wt or a TP53-knockout melanoma cell line. Immunoblot was applied to analyze the IFN-ɣ signaling pathway. Results For TP53-mutated tumors, an increased CD274 mRNA expression and a higher frequency of PD-L1 positivity was observed. Interestingly, positive correlations of IFNG mRNA and PD-L1 protein in both TP53-wt and -mutated samples and of p53 and PD-L1 protein suggest a non-transcriptional mode of action of p53. Indeed, cell line experiments revealed a diminished IFN-ɣ-induced PD-L1 expression upon p53 knockdown in both wildtype and TP53-mutated melanoma cells, which was not the case when p53 wildtype protein was rendered transcriptionally inactive or by ectopic expression of p53\(^{L22Q,W23S}\), a transcriptionally-impaired variant, in TP53-wt cells. Accordingly, expression of p53\(^{L22Q,W23S}\) in a TP53-knockout melanoma cell line boosted IFN-ɣ-induced PD-L1 expression. The impaired PD-L1-inducibility after p53 knockdown was associated with a reduced JAK2 expression in the cells and was almost abrogated by JAK2 overexpression. Conclusions While having only a small impact on basal PD-L1 expression, both wildtype and mutated p53 play an important positive role for IFN-ɣ-induced PD-L1 expression in melanoma cells by supporting JAK2 expression. Future studies should address, whether p53 expression levels might influence response to anti-PD-1 immunotherapy.},
  language  = {en}
}
@article{JahnDorbathKircheretal.2019,
  author    = {Jahn, Daniel and Dorbath, Donata and Kircher, Stefan and Nier, Anika and Bergheim, Ina and Lenaerts, Kaatje and Hermanns, Heike M. and Geier, Andreas},
  title     = {Beneficial effects of vitamin D treatment in an obese mouse model of non-alcoholic steatohepatitis},
  series = {Nutrients},
  volume    = {11},
  journal   = {Nutrients},
  number    = {1},
  doi       = {10.3390/nu11010077},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-177222},
  pages     = {77},
  year      = {2019},
  abstract  = {Serum vitamin D levels negatively correlate with obesity and associated disorders such as non-alcoholic steatohepatitis (NASH). However, the mechanisms linking low vitamin D (VD) status to disease progression are not completely understood. In this study, we analyzed the effect of VD treatment on NASH in mice. C57BL6/J mice were fed a high-fat/high-sugar diet (HFSD) containing low amounts of VD for 16 weeks to induce obesity, NASH and liver fibrosis. The effects of preventive and interventional VD treatment were studied on the level of liver histology and hepatic/intestinal gene expression. Interestingly, preventive and to a lesser extent also interventional VD treatment resulted in improvements of liver histology. This included a significant decrease of steatosis, a trend towards lower non-alcoholic fatty liver disease (NAFLD) activity score and a slight non-significant decrease of fibrosis in the preventive treatment group. In line with these changes, preventive VD treatment reduced the hepatic expression of lipogenic, inflammatory and pro-fibrotic genes. Notably, these beneficial effects occurred in conjunction with a reduction of intestinal inflammation. Together, our observations suggest that timely initiation of VD supplementation (preventive vs. interventional) is a critical determinant of treatment outcome in NASH. In the applied animal model, the improvements of liver histology occurred in conjunction with reduced inflammation in the gut, suggesting a potential relevance of vitamin D as a therapeutic agent acting on the gut-liver axis.},
  language  = {en}
}