TY - JOUR A1 - Kraft, Peter A1 - Schuhmann, Michael K. A1 - Garz, Cornelia A1 - Jandke, Solveig A1 - Urlaub, Daniela A1 - Mencl, Stine A1 - Zernecke, Alma A1 - Heinze, Hans-Jochen A1 - Carare, Roxana O. A1 - Kleinschnitz, Christoph A1 - Schreiber, Stefanie T1 - Hypercholesterolemia induced cerebral small vessel disease JF - PLoS ONE N2 - Background While hypercholesterolemia plays a causative role for the development of ischemic stroke in large vessels, its significance for cerebral small vessel disease (CSVD) remains unclear. We thus aimed to understand the detailed relationship between hypercholesterolemia and CSVD using the well described Ldlr\(^{−/-}\) mouse model. Methods We used Ldlr\(^{−/-}\) mice (n = 16) and wild-type (WT) mice (n = 15) at the age of 6 and 12 months. Ldlr\(^{−/-}\) mice develop high plasma cholesterol levels following a high fat diet. We analyzed cerebral capillaries and arterioles for intravascular erythrocyte accumulations, thrombotic vessel occlusions, blood-brain barrier (BBB) dysfunction and microbleeds. Results We found a significant increase in the number of erythrocyte stases in 6 months old Ldlr\(^{−/-}\) mice compared to all other groups (P < 0.05). Ldlr\(^{−/-}\) animals aged 12 months showed the highest number of thrombotic occlusions while in WT animals hardly any occlusions could be observed (P < 0.001). Compared to WT mice, Ldlr\(^{−/-}\) mice did not display significant gray matter BBB breakdown. Microhemorrhages were observed in one Ldlr\(^{−/-}\) mouse that was 6 months old. Results did not differ when considering subcortical and cortical regions. Conclusions In Ldlr\(^{−/-}\) mice, hypercholesterolemia is related to a thrombotic CSVD phenotype, which is different from hypertension-related CSVD that associates with a hemorrhagic CSVD phenotype. Our data demonstrate a relationship between hypercholesterolemia and the development of CSVD. Ldlr\(^{−/-}\) mice appear to be an adequate animal model for research into CSVD. KW - hypercholesterolemia KW - cerebral small vessel disease KW - mouse model KW - histology Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-170493 VL - 12 IS - 8 ER - TY - JOUR A1 - García-Betancur, Juan-Carlos A1 - Goñi-Moreno, Angel A1 - Horger, Thomas A1 - Schott, Melanie A1 - Sharan, Malvika A1 - Eikmeier, Julian A1 - Wohlmuth, Barbara A1 - Zernecke, Alma A1 - Ohlsen, Knut A1 - Kuttler, Christina A1 - Lopez, Daniel T1 - Cell differentiation defines acute and chronic infection cell types in Staphylococcus aureus JF - eLife N2 - A central question to biology is how pathogenic bacteria initiate acute or chronic infections. Here we describe a genetic program for cell-fate decision in the opportunistic human pathogen Staphylococcus aureus, which generates the phenotypic bifurcation of the cells into two genetically identical but different cell types during the course of an infection. Whereas one cell type promotes the formation of biofilms that contribute to chronic infections, the second type is planktonic and produces the toxins that contribute to acute bacteremia. We identified a bimodal switch in the agr quorum sensing system that antagonistically regulates the differentiation of these two physiologically distinct cell types. We found that extracellular signals affect the behavior of the agr bimodal switch and modify the size of the specialized subpopulations in specific colonization niches. For instance, magnesium-enriched colonization niches causes magnesium binding to S. aureusteichoic acids and increases bacterial cell wall rigidity. This signal triggers a genetic program that ultimately downregulates the agr bimodal switch. Colonization niches with different magnesium concentrations influence the bimodal system activity, which defines a distinct ratio between these subpopulations; this in turn leads to distinct infection outcomes in vitro and in an in vivo murine infection model. Cell differentiation generates physiological heterogeneity in clonal bacterial infections and helps to determine the distinct infection types. KW - Staphylococcus aureus KW - infection KW - cell differentiation KW - pathogenic bacteria Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-170346 VL - 6 IS - e28023 ER - TY - JOUR A1 - Wildgruber, Moritz A1 - Aschenbrenner, Teresa A1 - Wendorff, Heiko A1 - Czubba, Maria A1 - Glinzer, Almut A1 - Haller, Bernhard A1 - Schiemann, Matthias A1 - Zimmermann, Alexander A1 - Berger, Hermann A1 - Eckstein, Hans-Henning A1 - Meier, Reinhard A1 - Wohlgemuth, Walter A. A1 - Libby, Peter A1 - Zernecke, Alma T1 - The "Intermediate" CD14\(^{++}\)CD16\(^{+}\) monocyte subset increases in severe peripheral artery disease in humans JF - Scientific Reports N2 - Monocytes are key players in atherosclerotic. Human monocytes display a considerable heterogeneity and at least three subsets can be distinguished. While the role of monocyte subset heterogeneity has already been well investigated in coronary artery disease (CAD), the knowledge about monocytes and their heterogeneity in peripheral artery occlusive disease (PAOD) still is limited. Therefore, we aimed to investigate monocyte subset heterogeneity in patients with PAOD. Peripheral blood was obtained from 143 patients suffering from PAOD (Rutherford stage I to VI) and three monocyte subsets were identified by flow cytometry: CD14\(^{++}\)CD16\(^{-}\) classical monocytes, CD14\(^{+}\)CD16\(^{++}\) non-classical monocytes and CD14\(^{++}\)CD16\(^{+}\) intermediate monocytes. Additionally the expression of distinct surface markers (CD106, CD162 and myeloperoxidase MPO) was analyzed. Proportions of CD14\(^{++}\)CD16\(^{+}\) intermediate monocyte levels were significantly increased in advanced stages of PAOD, while classical and non-classical monocytes displayed no such trend. Moreover, CD162 and MPO expression increased significantly in intermediate monocyte subsets in advanced disease stages. Likewise, increased CD162 and MPO expression was noted in CD14\(^{++}\)CD16\(^{-}\) classical monocytes. These data suggest substantial dynamics in monocyte subset distributions and phenotypes in different stages of PAOD, which can either serve as biomarkers or as potential therapeutic targets to decrease the inflammatory burden in advanced stages of atherosclerosis. KW - peripheral artery occlusive disease KW - monocyte subset KW - humans Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-167476 VL - 6 IS - 39483 ER - TY - JOUR A1 - Zernecke, Alma T1 - Distinct functions of specialized dendritic cell subsets in atherosclerosis and the road ahead JF - Scientifica N2 - Atherosclerotic vascular disease is modulated by immune mechanisms. Dendritic cells (DCs) and T cells are present within atherosclerotic lesions and function as central players in the initiation and modulation of adaptive immune responses. In previous years, we have studied the functional contribution of distinct DC subsets in disease development, namely, that of CCL17-expressing DCs as well as that of plasmacytoid DCs that play specialized roles in disease development. This review focuses on important findings gathered in these studies and dissects the multifaceted contribution of CCL17-expressing DCs and pDCs to the pathogenesis of atherosclerosis. Furthermore, an outlook on future challenges faced when studying DCs in this detrimental disease are provided, and hurdles that will need to be overcome in order to enable a better understanding of the contribution of DCs to atherogenesis are discussed, a prerequisite for their therapeutic targeting in atherosclerosis. KW - atherosclerotic vascular disease Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-120241 VL - 2014 ER - TY - JOUR A1 - Busch, Martin A1 - Westhofen, Thilo C. A1 - Koch, Miriam A1 - Lutz, Manfred B. A1 - Zernecke, Alma T1 - Dendritic Cell Subset Distributions in the Aorta in Healthy and Atherosclerotic Mice JF - PLoS ONE N2 - Dendritic cells (DCs) can be sub-divided into various subsets that play specialized roles in priming of adaptive immune responses. Atherosclerosis is regarded as a chronic inflammatory disease of the vessel wall and DCs can be found in non-inflamed and diseased arteries. We here performed a systematic analyses of DCs subsets during atherogenesis. Our data indicate that distinct DC subsets can be localized in the vessel wall. In C57BL/6 and low density lipoprotein receptor-deficient (Ldlr−/−) mice, CD11c+ MHCII+ DCs could be discriminated into CD103− CD11b+F4/80+, CD11b+F4/80− and CD11b−F4/80− DCs and CD103+ CD11b−F4/80− DCs. Except for CD103− CD11b− F4/80− DCs, these subsets expanded in high fat diet-fed Ldlr−/− mice. Signal-regulatory protein (Sirp)-α was detected on aortic macrophages, CD11b+ DCs, and partially on CD103− CD11b− F4/80− but not on CD103+ DCs. Notably, in FMS-like tyrosine kinase 3-ligand-deficient (Flt3l−/−) mice, a specific loss of CD103+ DCs but also CD103− CD11b+ F4/80− DCs was evidenced. Aortic CD103+ and CD11b+ F4/80− CD103− DCs may thus belong to conventional rather than monocyte-derived DCs, given their dependence on Flt3L-signalling. CD64, postulated to distinguish macrophages from DCs, could not be detected on DC subsets under physiological conditions, but appeared in a fraction of CD103− CD11b+ F4/80− and CD11b+ F4/80+ cells in atherosclerotic Ldlr−/− mice. The emergence of CD64 expression in atherosclerosis may indicate that CD11b+ F4/80− DCs similar to CD11b+ F4/80+ DCs are at least in part derived from immigrated monocytes during atherosclerotic lesion formation. Our data advance our knowledge about the presence of distinct DC subsets and their accumulation characteristics in atherosclerosis, and may help to assist in future studies aiming at specific DC-based therapeutic strategies for the treatment of chronic vascular inflammation. KW - flow cytometry KW - monocytes KW - diet KW - cell staining KW - DAPI staining KW - aorta KW - macrophages Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-119907 SN - 1932-6203 VL - 9 IS - 2 ER - TY - JOUR A1 - Cochain, Clement A1 - Chaudhari, Sweena M. A1 - Koch, Miriam A1 - Wiendl, Heinz A1 - Eckstein, Hans-Henning A1 - Zernecke, Alma T1 - Programmed Cell Death-1 Deficiency Exacerbates T Cell Activation and Atherogenesis despite Expansion of Regulatory T Cells in Atherosclerosis-Prone Mice JF - PLoS ONE N2 - T cell activation represents a double-edged sword in atherogenesis, as it promotes both pro-inflammatory T cell activation and atheroprotective Foxp3(+) regulatory T cell (Treg) responses. Here, we investigated the role of the co-inhibitory receptor programmed cell death-1 (PD-1) in T cell activation and CD4(+) T cell polarization towards pro-atherogenic or atheroprotective responses in mice. Mice deficient for both low density lipoprotein receptor and PD-1 (Ldlr(-/-)Pd1(-/-)) displayed striking increases in systemic CD4(+) and CD8(+) T cell activation after 9 weeks of high fat diet feeding, associated with an expansion of both pro-atherogenic IFNγ-secreting T helper 1 cells and atheroprotective Foxp3+ Tregs. Importantly, PD-1 deficiency did not affect Treg suppressive function in vitro. Notably, PD-1 deficiency exacerbated atherosclerotic lesion growth and entailed a massive infiltration of T cells in atherosclerotic lesions. In addition, aggravated hypercholesterolemia was observed in Ldlr(-/-)Pd1(-/-) mice. In conclusion, we here demonstrate that although disruption of PD-1 signaling enhances both pro- and anti-atherogenic T cell responses in Ldlr(-/-) mice, pro-inflammatory T cell activation prevails and enhances dyslipidemia, vascular inflammation and atherosclerosis. KW - nutritional deficiencies KW - atherosclerosis KW - spleen KW - aorta KW - diet KW - cytotoxic T cells KW - regulatory T cells KW - T cells Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-119823 SN - 1932-6203 VL - 9 IS - 4 ER - TY - JOUR A1 - Rowinska, Zuzanna A1 - Gorressen, Simone A1 - Merx, Marc W. A1 - Koeppel, Thomas A. A1 - Liehn, Elisa A. A1 - Zernecke, Alma T1 - Establishment of a New Murine Elastase-Induced Aneurysm Model Combined with Transplantation JF - PLOS ONE N2 - Introduction: The aim of our study was to develop a reproducible murine model of elastase-induced aneurysm formation combined with aortic transplantation. Methods: Adult male mice (n = 6-9 per group) underwent infrarenal, orthotopic transplantation of the aorta treated with elastase or left untreated. Subsequently, both groups of mice were monitored by ultrasound until 7 weeks after grafting. Results: Mice receiving an elastase-pretreated aorta developed aneurysms and exhibited a significantly increased diastolic vessel diameter compared to control grafted mice at 7 week after surgery (1.11 +/- 0.10 mm vs. 0.75 +/- 0.03 mm; p <= 0.001). Histopathological examination revealed disruption of medial elastin, an increase in collagen content and smooth muscle cells, and neointima formation in aneurysm grafts. Conclusions: We developed a reproducible murine model of elastase-induced aneurysm combined with aortic transplantation. This model may be suitable to investigate aneurysm-specific inflammatory processes and for use in gene-targeted animals. KW - abdominal aortic-aneurysm KW - mouse models KW - prediction KW - dilation KW - rupture Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-115774 SN - 1932-6203 VL - 9 IS - 7 ER -