@article{SchuhmannLanghauserKraftetal.2017, author = {Schuhmann, Michael K. and Langhauser, Friederike and Kraft, Peter and Kleinschnitz, Christoph}, title = {B cells do not have a major pathophysiologic role in acute ischemic stroke in mice}, series = {Journal of Neuroinflammation}, volume = {14}, journal = {Journal of Neuroinflammation}, number = {112}, doi = {10.1186/s12974-017-0890-x}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-158155}, year = {2017}, abstract = {Background Lymphocytes have been shown to play an important role in the pathophysiology of acute ischemic stroke, but the properties of B cells remain controversial. The aim of this study was to unravel the role of B cells during acute cerebral ischemia using pharmacologic B cell depletion, B cell transgenic mice, and adoptive B cell transfer experiments. Methods Transient middle cerebral artery occlusion (60 min) was induced in wild-type mice treated with an anti-CD20 antibody 24 h before stroke onset, JHD\(^{-/-}\) mice and Rag1\(^{-/-}\) mice 24 h after adoptive B cell transfer. Stroke outcome was assessed at days 1 and 3. Infarct volumes were calculated from 2,3,5-triphenyltetrazolium chloride (TTC)-stained brain sections, and neurological scores were evaluated. The local inflammatory response was determined by real-time PCR and immunohistochemistry. Apoptosis was analyzed by TUNEL staining, and astrocyte activation was revealed using immunohistochemistry and Western blot. Results Pharmacologic depletion of B cells did not influence infarct volumes and functional outcome at day 1 after stroke. Additionally, lack of circulating B cells in JHD\(^{-/-}\) mice also failed to influence stroke outcome at days 1 and 3. Furthermore, reconstitution of Rag1\(^{-/-}\) mice with B cells had no influence on infarct volumes. Conclusion Targeting B cells in experimental stroke did not influence lesion volume and functional outcome during the acute phase. Our findings argue against a major pathophysiologic role of B cells during acute ischemic stroke.}, language = {en} } @article{SchuhmannGuthmannStolletal.2017, author = {Schuhmann, Michael K. and Guthmann, Josua and Stoll, Guido and Nieswandt, Bernhard and Kraft, Peter and Kleinschnitz, Christoph}, title = {Blocking of platelet glycoprotein receptor Ib reduces "thrombo-inflammation" in mice with acute ischemic stroke}, series = {Journal of Neuroinflammation}, volume = {14}, journal = {Journal of Neuroinflammation}, number = {18}, doi = {10.1186/s12974-017-0792-y}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-157582}, year = {2017}, abstract = {Background: Ischemic stroke causes a strong inflammatory response that includes T cells, monocytes/macrophages, and neutrophils. Interaction of these immune cells with platelets and endothelial cells facilitates microvascular dysfunction and leads to secondary infarct growth. We recently showed that blocking of platelet glycoprotein (GP) receptor Ib improves stroke outcome without increasing the risk of intracerebral hemorrhage. Until now, it has been unclear whether GPIb only mediates thrombus formation or also contributes to the pathophysiology of local inflammation. Methods: Focal cerebral ischemia was induced in C57BL/6 mice by a 60-min transient middle cerebral artery occlusion (tMCAO). Animals were treated with antigen-binding fragments (Fab) against the platelet surface molecules GPIb (p0p/B Fab). Rat immunoglobulin G (IgG) Fab was used as control treatment. Stroke outcome, including infarct size and functional deficits as well as the local inflammatory response, was assessed on day 1 after tMCAO. Results: Blocking of GPIb reduced stroke size and improved functional outcome on day 1 after tMCAO without increasing the risk of intracerebral hemorrhage. As expected, disruption of GPIb-mediated pathways in platelets significantly reduced thrombus burden in the cerebral microvasculature. In addition, inhibition of GPIb limited the local inflammatory response in the ischemic brain as indicated by lower numbers of infiltrating T cells and macrophages and lower expression levels of inflammatory cytokines compared with rat IgG Fab-treated controls. Conclusion: In acute ischemic stroke, thrombus formation and inflammation are closely intertwined ("thrombo-inflammation"). Blocking of platelet GPIb can ameliorate thrombo-inflammation.}, language = {en} } @article{SchuhmannFluri2017, author = {Schuhmann, Michael K. and Fluri, Felix}, title = {Effects of fullerenols on mouse brain microvascular endothelial cells}, series = {International Journal of Molecular Sciences}, volume = {18}, journal = {International Journal of Molecular Sciences}, number = {8}, issn = {1422-0067}, doi = {10.3390/ijms18081783}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-158072}, year = {2017}, abstract = {Fullerenols, water-soluble C60-fullerene derivatives, have been shown to exert neuroprotective effects in vitro and in vivo, most likely due to their capability to scavenge free radicals. However, little is known about the effects of fullerenols on the blood-brain barrier (BBB), especially on cerebral endothelial cells under inflammatory conditions. Here, we investigated whether the treatment of primary mouse brain microvascular endothelial cells with fullerenols impacts basal and inflammatory blood-brain barrier (BBB) properties in vitro. While fullerenols (1, 10, and 100 µg/mL) did not change transendothelial electrical resistance under basal and inflammatory conditions, 100 µg/mL of fullerenol significantly reduced erk1/2 activation and resulted in an activation of NFκB in an inflammatory milieu. Our findings suggest that fullerenols might counteract oxidative stress via the erk1/2 and NFκB pathways, and thus are able to protect microvascular endothelial cells under inflammatory conditions.}, language = {en} } @article{KraftSchuhmannGarzetal.2017, author = {Kraft, Peter and Schuhmann, Michael K. and Garz, Cornelia and Jandke, Solveig and Urlaub, Daniela and Mencl, Stine and Zernecke, Alma and Heinze, Hans-Jochen and Carare, Roxana O. and Kleinschnitz, Christoph and Schreiber, Stefanie}, title = {Hypercholesterolemia induced cerebral small vessel disease}, series = {PLoS ONE}, volume = {12}, journal = {PLoS ONE}, number = {8}, doi = {10.1371/journal.pone.0182822}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-170493}, pages = {e0182822}, year = {2017}, abstract = {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.}, language = {en} }