@article{AndreskaLueningschroerWolfetal.2023,
  author    = {Andreska, Thomas and L{\"u}ningschr{\"o}r, Patrick and Wolf, Daniel and McFleder, Rhonda L. and Ayon-Olivas, Maurilyn and Rattka, Marta and Drechsler, Christine and Perschin, Veronika and Blum, Robert and Aufmkolk, Sarah and Granado, Noelia and Moratalla, Rosario and Sauer, Markus and Monoranu, Camelia and Volkmann, Jens and Ip, Chi Wang and Stigloher, Christian and Sendtner, Michael},
  title     = {DRD1 signaling modulates TrkB turnover and BDNF sensitivity in direct pathway striatal medium spiny neurons},
  series = {Cell Reports},
  volume    = {42},
  journal   = {Cell Reports},
  number    = {6},
  doi       = {10.1016/j.celrep.2023.112575},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-349932},
  year      = {2023},
  abstract  = {Highlights • Dopamine receptor-1 activation induces TrkB cell-surface expression in striatal neurons • Dopaminergic deficits cause TrkB accumulation and clustering in the ER • TrkB clusters colocalize with cargo receptor SORCS-2 in direct pathway striatal neurons • Intracellular TrkB clusters fail to fuse with lysosomes after dopamine depletion Summary Disturbed motor control is a hallmark of Parkinson's disease (PD). Cortico-striatal synapses play a central role in motor learning and adaption, and brain-derived neurotrophic factor (BDNF) from cortico-striatal afferents modulates their plasticity via TrkB in striatal medium spiny projection neurons (SPNs). We studied the role of dopamine in modulating the sensitivity of direct pathway SPNs (dSPNs) to BDNF in cultures of fluorescence-activated cell sorting (FACS)-enriched D1-expressing SPNs and 6-hydroxydopamine (6-OHDA)-treated rats. DRD1 activation causes enhanced TrkB translocation to the cell surface and increased sensitivity for BDNF. In contrast, dopamine depletion in cultured dSPN neurons, 6-OHDA-treated rats, and postmortem brain of patients with PD reduces BDNF responsiveness and causes formation of intracellular TrkB clusters. These clusters associate with sortilin related VPS10 domain containing receptor 2 (SORCS-2) in multivesicular-like structures, which apparently protects them from lysosomal degradation. Thus, impaired TrkB processing might contribute to disturbed motor function in PD.},
  language  = {en}
}
@article{GrotemeyerFischerKoprichetal.2023,
  author    = {Grotemeyer, Alexander and Fischer, Judith F. and Koprich, James B. and Brotchie, Jonathan M. and Blum, Robert and Volkmann, Jens and Ip, Chi Wang},
  title     = {Inflammasome inhibition protects dopaminergic neurons from α-synuclein pathology in a model of progressive Parkinson's disease},
  series = {Journal of Neuroinflammation},
  volume    = {20},
  journal   = {Journal of Neuroinflammation},
  doi       = {10.1186/s12974-023-02759-0},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-357652},
  year      = {2023},
  abstract  = {Neuroinflammation has been suggested as a pathogenetic mechanism contributing to Parkinson's disease (PD). However, anti-inflammatory treatment strategies have not yet been established as a therapeutic option for PD patients. We have used a human α-synuclein mouse model of progressive PD to examine the anti-inflammatory and neuroprotective effects of inflammasome inhibition on dopaminergic (DA) neurons in the substantia nigra (SN). As the NLRP3 (NOD-, LRR- and pyrin domain-containing 3)-inflammasome is a core interface for both adaptive and innate inflammation and is also highly druggable, we investigated the implications of its inhibition. Repeat administration of MCC950, an inhibitor of NLRP3, in a PD model with ongoing pathology reduced CD4\(^+\) and CD8\(^+\) T cell infiltration into the SN. Furthermore, the anti-inflammasome treatment mitigated microglial activation and modified the aggregation of α-synuclein protein in DA neurons. MCC950-treated mice showed significantly less neurodegeneration of DA neurons and a reduction in PD-related motor behavior. In summary, early inflammasome inhibition can reduce neuroinflammation and prevent DA cell death in an α-synuclein mouse model for progressive PD.},
  language  = {en}
}
@article{GriebelSegebarthSteinetal.2023,
  author    = {Griebel, Matthias and Segebarth, Dennis and Stein, Nikolai and Schukraft, Nina and Tovote, Philip and Blum, Robert and Flath, Christoph M.},
  title     = {Deep learning-enabled segmentation of ambiguous bioimages with deepflash2},
  series = {Nature Communications},
  volume    = {14},
  journal   = {Nature Communications},
  doi       = {10.1038/s41467-023-36960-9},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-357286},
  year      = {2023},
  abstract  = {Bioimages frequently exhibit low signal-to-noise ratios due to experimental conditions, specimen characteristics, and imaging trade-offs. Reliable segmentation of such ambiguous images is difficult and laborious. Here we introduce deepflash2, a deep learning-enabled segmentation tool for bioimage analysis. The tool addresses typical challenges that may arise during the training, evaluation, and application of deep learning models on ambiguous data. The tool's training and evaluation pipeline uses multiple expert annotations and deep model ensembles to achieve accurate results. The application pipeline supports various use-cases for expert annotations and includes a quality assurance mechanism in the form of uncertainty measures. Benchmarked against other tools, deepflash2 offers both high predictive accuracy and efficient computational resource usage. The tool is built upon established deep learning libraries and enables sharing of trained model ensembles with the research community. deepflash2 aims to simplify the integration of deep learning into bioimage analysis projects while improving accuracy and reliability.},
  language  = {en}
}
@article{LuxHuBenKraiemetal.2019,
  author    = {Lux, Thomas J. and Hu, Xiawei and Ben-Kraiem, Adel and Blum, Robert and Chen, Jeremy Tsung-Chieh and Rittner, Heike L.},
  title     = {Regional differences in tight junction protein expression in the blood-DRG barrier and their alterations after nerve traumatic injury in rats},
  series = {International Journal of Molecular Sciences},
  volume    = {21},
  journal   = {International Journal of Molecular Sciences},
  number    = {1},
  issn      = {1422-0067},
  doi       = {10.3390/ijms21010270},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-285029},
  year      = {2019},
  abstract  = {The nervous system is shielded by special barriers. Nerve injury results in blood-nerve barrier breakdown with downregulation of certain tight junction proteins accompanying the painful neuropathic phenotype. The dorsal root ganglion (DRG) consists of a neuron-rich region (NRR, somata of somatosensory and nociceptive neurons) and a fibre-rich region (FRR), and their putative epi-/perineurium (EPN). Here, we analysed blood-DRG barrier (BDB) properties in these physiologically distinct regions in Wistar rats after chronic constriction injury (CCI). Cldn5, Cldn12, and Tjp1 (rats) mRNA were downregulated 1 week after traumatic nerve injury. Claudin-1 immunoreactivity (IR) found in the EPN, claudin-19-IR in the FRR, and ZO-1-IR in FRR-EPN were unaltered after CCI. However, laser-assisted, vessel specific qPCR, and IR studies confirmed a significant loss of claudin-5 in the NRR. The NRR was three-times more permeable compared to the FRR for high and low molecular weight markers. NRR permeability was not further increased 1-week after CCI, but significantly more CD68\(^+\) macrophages had migrated into the NRR. In summary, NRR and FRR are different in na{\"i}ve rats. Short-term traumatic nerve injury leaves the already highly permeable BDB in the NRR unaltered for small and large molecules. Claudin-5 is downregulated in the NRR. This could facilitate macrophage invasion, and thereby neuronal sensitisation and hyperalgesia. Targeting the stabilisation of claudin-5 in microvessels and the BDB barrier could be a future approach for neuropathic pain therapy.},
  language  = {en}
}
@article{PolatWohllebenKosmalaetal.2022,
  author    = {Polat, B{\"u}lent and Wohlleben, Gisela and Kosmala, Rebekka and Lisowski, Dominik and Mantel, Frederick and Lewitzki, Victor and L{\"o}hr, Mario and Blum, Robert and Herud, Petra and Flentje, Michael and Monoranu, Camelia-Maria},
  title     = {Differences in stem cell marker and osteopontin expression in primary and recurrent glioblastoma},
  series = {Cancer Cell International},
  volume    = {22},
  journal   = {Cancer Cell International},
  issn      = {1475-2867},
  doi       = {10.1186/s12935-022-02510-4},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-301240},
  year      = {2022},
  abstract  = {Background Despite of a multimodal approach, recurrences can hardly be prevented in glioblastoma. This may be in part due to so called glioma stem cells. However, there is no established marker to identify these stem cells. Methods Paired samples from glioma patients were analyzed by immunohistochemistry for expression of the following stem cell markers: CD133, Musashi, Nanog, Nestin, octamer-binding transcription factor 4 (Oct4), and sex determining region Y-box 2 (Sox2). In addition, the expression of osteopontin (OPN) was investigated. The relative number of positively stained cells was determined. By means of Kaplan-Meier analysis, a possible association with overall survival by marker expression was investigated. Results Sixty tissue samples from 30 patients (17 male, 13 female) were available for analysis. For Nestin, Musashi and OPN a significant increase was seen. There was also an increase (not significant) for CD133 and Oct4. Patients with mutated Isocitrate Dehydrogenase-1/2 (IDH-1/2) status had a reduced expression for CD133 and Nestin in their recurrent tumors. Significant correlations were seen for CD133 and Nanog between OPN in the primary and recurrent tumor and between CD133 and Nestin in recurrent tumors. By confocal imaging we could demonstrate a co-expression of CD133 and Nestin within recurrent glioma cells. Patients with high CD133 expression had a worse prognosis (22.6 vs 41.1 months, p = 0.013). A similar trend was seen for elevated Nestin levels (24.9 vs 41.1 months, p = 0.08). Conclusions Most of the evaluated markers showed an increased expression in their recurrent tumor. CD133 and Nestin were associated with survival and are candidate markers for further clinical investigation.},
  language  = {en}
}
@article{SchulteBlum2022,
  author    = {Schulte, Annemarie and Blum, Robert},
  title     = {Shaped by leaky ER: Homeostatic Ca\(^{2+}\) fluxes},
  series = {Frontiers in Physiology},
  volume    = {13},
  journal   = {Frontiers in Physiology},
  issn      = {1664-042X},
  doi       = {10.3389/fphys.2022.972104},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-287102},
  year      = {2022},
  abstract  = {At any moment in time, cells coordinate and balance their calcium ion (Ca\(^{2+}\)) fluxes. The term 'Ca\(^{2+}\) homeostasis' suggests that balancing resting Ca2+ levels is a rather static process. However, direct ER Ca\(^{2+}\) imaging shows that resting Ca\(^{2+}\) levels are maintained by surprisingly dynamic Ca\(^{2+}\) fluxes between the ER Ca\(^{2+}\) store, the cytosol, and the extracellular space. The data show that the ER Ca\(^{2+}\) leak, continuously fed by the high-energy consuming SERCA, is a fundamental driver of resting Ca\(^{2+}\) dynamics. Based on simplistic Ca\(^{2+}\) toolkit models, we discuss how the ER Ca\(^{2+}\) leak could contribute to evolutionarily conserved Ca\(^{2+}\) phenomena such as Ca\(^{2+}\) entry, ER Ca\(^{2+}\) release, and Ca\(^{2+}\) oscillations.},
  language  = {en}
}
@article{KarikariMcFlederRibechinietal.2022,
  author    = {Karikari, Akua A. and McFleder, Rhonda L. and Ribechini, Eliana and Blum, Robert and Bruttel, Valentin and Knorr, Susanne and Gehmeyr, Mona and Volkmann, Jens and Brotchie, Jonathan M. and Ahsan, Fadhil and Haack, Beatrice and Monoranu, Camelia-Maria and Keber, Ursula and Yeghiazaryan, Rima and Pagenstecher, Axel and Heckel, Tobias and Bischler, Thorsten and Wischhusen, J{\"o}rg and Koprich, James B. and Lutz, Manfred B. and Ip, Chi Wang},
  title     = {Neurodegeneration by α-synuclein-specific T cells in AAV-A53T-α-synuclein Parkinson's disease mice},
  series = {Brain, Behavior, and Immunity},
  volume    = {101},
  journal   = {Brain, Behavior, and Immunity},
  doi       = {10.1016/j.bbi.2022.01.007},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-300600},
  pages     = {194 -- 210},
  year      = {2022},
  abstract  = {Background Antigen-specific neuroinflammation and neurodegeneration are characteristic for neuroimmunological diseases. In Parkinson's disease (PD) pathogenesis, α-synuclein is a known culprit. Evidence for α-synuclein-specific T cell responses was recently obtained in PD. Still, a causative link between these α-synuclein responses and dopaminergic neurodegeneration had been lacking. We thus addressed the functional relevance of α-synuclein-specific immune responses in PD in a mouse model. Methods We utilized a mouse model of PD in which an Adeno-associated Vector 1/2 serotype (AAV1/2) expressing human mutated A53T-α-Synuclein was stereotactically injected into the substantia nigra (SN) of either wildtype C57BL/6 or Recombination-activating gene 1 (RAG1)\(^{-/-}\) mice. Brain, spleen, and lymph node tissues from different time points following injection were then analyzed via FACS, cytokine bead assay, immunohistochemistry and RNA-sequencing to determine the role of T cells and inflammation in this model. Bone marrow transfer from either CD4\(^{+}\)/CD8\(^{-}\), CD4\(^{-}\)/CD8\(^{+}\), or CD4\(^{+}\)/CD8\(^{+}\) (JHD\(^{-/-}\)) mice into the RAG-1\(^{-/-}\) mice was also employed. In addition to the in vivo studies, a newly developed A53T-α-synuclein-expressing neuronal cell culture/immune cell assay was utilized. Results AAV-based overexpression of pathogenic human A53T-α-synuclein in dopaminergic neurons of the SN stimulated T cell infiltration. RNA-sequencing of immune cells from PD mouse brains confirmed a pro-inflammatory gene profile. T cell responses were directed against A53T-α-synuclein-peptides in the vicinity of position 53 (68-78) and surrounding the pathogenically relevant S129 (120-134). T cells were required for α-synuclein-induced neurodegeneration in vivo and in vitro, while B cell deficiency did not protect from dopaminergic neurodegeneration. Conclusions Using T cell and/or B cell deficient mice and a newly developed A53T-α-synuclein-expressing neuronal cell culture/immune cell assay, we confirmed in vivo and in vitro that pathogenic α-synuclein peptide-specific T cell responses can cause dopaminergic neurodegeneration and thereby contribute to PD-like pathology.},
  language  = {en}
}
@article{BenKraiemSauerNorwigetal.2021,
  author    = {Ben-Kraiem, Adel and Sauer, Reine-Solange and Norwig, Carla and Popp, Maria and Bettenhausen, Anna-Lena and Atalla, Mariam Sobhy and Brack, Alexander and Blum, Robert and Doppler, Kathrin and Rittner, Heike Lydia},
  title     = {Selective blood-nerve barrier leakiness with claudin-1 and vessel-associated macrophage loss in diabetic polyneuropathy},
  series = {Journal of Molecular Medicine},
  volume    = {99},
  journal   = {Journal of Molecular Medicine},
  number    = {9},
  doi       = {10.1007/s00109-021-02091-1},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-265237},
  pages     = {1237-1250},
  year      = {2021},
  abstract  = {Diabetic polyneuropathy (DPN) is the most common complication in diabetes and can be painful in up to 26\% of all diabetic patients. Peripheral nerves are shielded by the blood-nerve barrier (BNB) consisting of the perineurium and endoneurial vessels. So far, there are conflicting results regarding the role and function of the BNB in the pathophysiology of DPN. In this study, we analyzed the spatiotemporal tight junction protein profile, barrier permeability, and vessel-associated macrophages in Wistar rats with streptozotocin-induced DPN. In these rats, mechanical hypersensitivity developed after 2 weeks and loss of motor function after 8 weeks, while the BNB and the blood-DRG barrier were leakier for small, but not for large molecules after 8 weeks only. The blood-spinal cord barrier remained sealed throughout the observation period. No gross changes in tight junction protein or cytokine expression were observed in all barriers to blood. However, expression of Cldn1 mRNA in perineurium was specifically downregulated in conjunction with weaker vessel-associated macrophage shielding of the BNB. Our results underline the role of specific tight junction proteins and BNB breakdown in DPN maintenance and differentiate DPN from traumatic nerve injury. Targeting claudins and sealing the BNB could stabilize pain and prevent further nerve damage.},
  language  = {en}
}
@article{SchuhmannPappStolletal.2021,
  author    = {Schuhmann, Michael K. and Papp, Lena and Stoll, Guido and Blum, Robert and Volkmann, Jens and Fluri, Felix},
  title     = {Mesencephalic electrical stimulation reduces neuroinflammation after photothrombotic stroke in rats by targeting the cholinergic anti-inflammatory pathway},
  series = {International Journal of Molecular Sciences},
  volume    = {22},
  journal   = {International Journal of Molecular Sciences},
  number    = {3},
  issn      = {1422-0067},
  doi       = {10.3390/ijms22031254},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-259099},
  year      = {2021},
  abstract  = {Inflammation is crucial in the pathophysiology of stroke and thus a promising therapeutic target. High-frequency stimulation (HFS) of the mesencephalic locomotor region (MLR) reduces perilesional inflammation after photothrombotic stroke (PTS). However, the underlying mechanism is not completely understood. Since distinct neural and immune cells respond to electrical stimulation by releasing acetylcholine, we hypothesize that HFS might trigger the cholinergic anti-inflammatory pathway via activation of the α7 nicotinic acetylcholine receptor (α7nAchR). To test this hypothesis, rats underwent PTS and implantation of a microelectrode into the MLR. Three hours after intervention, either HFS or sham-stimulation of the MLR was applied for 24 h. IFN-γ, TNF-α, and IL-1α were quantified by cytometric bead array. Choline acetyltransferase (ChAT)\(^+\) CD4\(^+\)-cells and α7nAchR\(^+\)-cells were quantified visually using immunohistochemistry. Phosphorylation of NFĸB, ERK1/2, Akt, and Stat3 was determined by Western blot analyses. IFN-γ, TNF-α, and IL-1α were decreased in the perilesional area of stimulated rats compared to controls. The number of ChAT\(^+\) CD4\(^+\)-cells increased after MLR-HFS, whereas the amount of α7nAchR\(^+\)-cells was similar in both groups. Phospho-ERK1/2 was reduced significantly in stimulated rats. The present study suggests that MLR-HFS may trigger anti-inflammatory processes within the perilesional area by modulating the cholinergic system, probably via activation of the α7nAchR.},
  language  = {en}
}
@article{OehlerBrackBlumetal.2021,
  author    = {Oehler, Beatrice and Brack, Alexander and Blum, Robert and Rittner, Heike L.},
  title     = {Pain Control by Targeting Oxidized Phospholipids: Functions, Mechanisms, Perspectives},
  series = {Frontiers in Endocrinology},
  volume    = {11},
  journal   = {Frontiers in Endocrinology},
  issn      = {1664-2392},
  doi       = {10.3389/fendo.2020.613868},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-223432},
  year      = {2021},
  abstract  = {Within the lipidome oxidized phospholipids (OxPL) form a class of chemically highly reactive metabolites. OxPL are acutely produced in inflamed tissue and act as endogenous, proalgesic (pain-inducing) metabolites. They excite sensory, nociceptive neurons by activating transient receptor potential ion channels, specifically TRPA1 and TRPV1. Under inflammatory conditions, OxPL-mediated receptor potentials even potentiate the action potential firing rate of nociceptors. Targeting OxPL with D-4F, an apolipoprotein A-I mimetic peptide or antibodies like E06, specifically binding oxidized headgroups of phospholipids, can be used to control acute, inflammatory pain syndromes, at least in rodents. With a focus on proalgesic specificities of OxPL, this article discusses, how targeting defined substances of the epilipidome can contribute to mechanism-based therapies against primary and secondary chronic inflammatory or possibly also neuropathic pain.},
  language  = {en}
}