Recent evidence suggests that astrocytes play an important role in regulating de- and remyelination in multiple sclerosis. The role of astrocytes is controversial, and both beneficial as well as ...detrimental effects are being discussed. We performed loss-of-function studies based on astrocyte depletion in a cuprizone-induced rodent model of demyelination. This led to strong astrogliosis accompanied by microgliosis and demyelination in C57BL/6 wild-type mice. Ablation of astrocytes in glial fibrillary acidic protein-thymidine kinase transgenic mice was associated with a failure of damaged myelin removal and a consecutive delay in remyelination. Despite oligodendrocyte death, myelin was still present, but ultrastructual investigations showed that the myelin structure was loosened and this damaged myelin did not protect axons. These alterations were associated with a decrease in microglial activation. Thus, our results show that astrocyte loss does not prevent myelin damage, but clearance of damaged myelin through recruitment of microglia is impaired. Further studies suggest that this process is regulated by the chemokine CXCL10. As a consequence of the delayed removal of myelin debris, remyelination and oligodendrocyte precursor cell proliferation were impaired. Experiments omitting the influence of myelin debris demonstrated an additional beneficial effect of astrocytes on oligodendrocyte regeneration during remyelination. In conclusion, these data demonstrate for the first time in vivo that astrocytes provide the signal environment that forms the basis for the recruitment of microglia to clear myelin debris, a process required for subsequent repair mechanisms. This is of great importance to understanding regenerative processes in demyelinating diseases such as multiple sclerosis.
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by abnormal protein aggregation in the motor neurons. Present and earlier proteomic studies to characterize peptides ...in cerebrospinal fluid (CSF) associated with motoneuron pathology did not target low molecular weight proteins and peptides. We hypothesized that specific changes in CSF peptides or low molecular weight proteins are significantly altered in ALS, and that these changes may support deciphering molecular pathophysiology and even guide approaches towards therapeutic interventions.
Cerebrospinal fluid (CSF) from 50 ALS patients and 50 non-ALS controls was collected, centrifuged immediately after collection, aliquoted into polypropylene test tubes, frozen within 30-40 min after the puncture, and stored at -80°C until use. Peptides were sequenced using capillary electrophoresis or liquid chromatography/mass spectrometry (CE-MS/MS or LC-MS/MS).
In the CSF of 50 patients and 50 non-ALS controls 33 peptides were found, of which 14 could be sequenced using a non-lytic single-pot proteomic detection method, CE/MS. ALS deregulated peptides vs. controls included Integral membrane protein 2B, Neurosecretory protein VGF, Osteopontin, Neuroendocrine protein 7B2 (Secretogranin-V), EGF-containing fibulin-like extracellular matrix protein 1, Xylosyltransferase 1 XT-1, Chromogranin-A, Superoxide dismutase SOD-1, Secretogranin-1 (Chromogranin B), NR2F2 Nuclear Receptor Subfamily 2 Group F Member 2 and Collagen alpha-1(VII) chain.
Most striking deregulations in CSF from ALS patients were found in VGF, Osteopontin, SOD-1 and EFEMP1 peptides. No associations of disease severity, duration and region of onset with sequenced peptides were found.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Immune checkpoint inhibitor (ICI) therapy has revolutionized the management of various cancers with previously poor prognosis. Despite its great efficacy, the therapy is associated with a wide ...spectrum of immune-related adverse events (irAE) including neurological symptoms which can affect all parts of the central and peripheral nervous system. Even though these events are rare, they are of high relevance as the rate of residual symptoms or even fatal outcomes is remarkable. To provide a detailed overview of neurological adverse events associated with immune checkpoint-inhibitor therapy we conducted a literature search. While focusing on ipilimumab, nivolumab, and pembrolizumab therapy, all available case reports as well as larger case series and clinical trials have been considered. Eighty-two case reports about checkpoint-inhibitor therapy induced symptoms of the peripheral nervous system have been published, while only 43 case reports addressed central nervous system abnormalities. The frequency of immune checkpoint-inhibitor therapy inducing neurological adverse events is about 1% in larger studies. Especially neuromuscular adverse events exhibit distinct clinical and diagnostic characteristics. Additionally, several affected patients presented with overlap-syndromes, which means that symptoms and diagnostic findings indicating myositis, myasthenia gravis, and neuropathy were present in one individual patient at the same time. Thus, neurological and particularly neuromuscular adverse events of immune checkpoint-inhibitor therapy may constitute a new disease entity.
Abstract Microglia play a key role in the initiation and perpetuation of de- and remyelination because of their ability to present antigens and clear cell debris by phagocytosis. Different factors ...expressed or secreted by microglia seem to play an important role in regenerative processes. But it remains unclear which factors lead to a protective microglial phenotype and recent data indicate region-specific differences within the central nervous system (CNS) for both de-/remyelination and microglial response. In order to identify important factors that promote neuroprotection, we examined changes in microglial phenotypes in the cuprizone model. We undertook an extensive and detailed analysis of the expression of surface markers as well as cytokines, growth factors, and the phagocytosis activity of microglia. We found a pronounced increase of phagocytosis activity of microglia during demyelination associated with an upregulation of phagocytic receptors, from which TREM-2b was the most prominent. The expression of MHC II was only increased at the peak of demyelination but costimulatory molecules showed no significant changes. Interestingly, the proinflammatory cytokine TNF-α was upregulated while the anti-inflammatory cytokines IL-10 and TGF-ß remained unchanged. The growth factors IFG-1 and FGF-2, which were both suggested to promote remyelination, were increased during demyelination. Our findings characterise changes of microglial markers during de- and remyelination indicating that debris clearance mediated via TREM-2b plays a central role in the regulation of these processes. Microglial phagocytosis as well as production of TNF-α, IGF-1, and FGF-2 seems to be important factors for the creation of an environment promoting regeneration.
A broad spectrum of diseases is characterized by myelin abnormalities and/or oligodendrocyte pathology. In most, if not all, of these diseases, early activation of microglia occurs. Our knowledge ...regarding the factors triggering early microglia activation is, however, incomplete. In this study, we used the cuprizone model to investigate the temporal and causal relationship of oligodendrocyte apoptosis and early microglia activation. Genome-wide gene expression studies revealed the induction of distinct chemokines, among them Cxcl10, Ccl2, and Ccl3 in cuprizone-mediated oligodendrocyte apoptosis. Early microglia activation was unchanged in CCL2- and CCL3-deficient knockouts, but was significantly reduced in CXCL10-deficient mice, resulting in an amelioration of cuprizone toxicity at later time points. Subsequent in vitro experiments revealed that recombinant CXCL10 induced migration and a proinflammatory phenotype in cultured microglia, without affecting their phagocytic activity or proliferation. In situ hybridization analyses suggest that Cxcl10 mRNA is mainly expressed by astrocytes, but also oligodendrocytes, in short-term cuprizone-exposed mice. Our results show that CXCL10 actively participates in the initiation of microglial activation. These findings have implications for the role of CXCL10 as an important mediator during the initiation of neuroinflammatory processes associated with oligodendrocyte pathology.
Sjögren's syndrome is a heterogeneous inflammatory disorder frequently involving peripheral nerves with a wide spectrum of sensory modalities and distribution patterns. The objective of this ...cross-sectional study was to determine characteristics of Sjögren's syndrome as a cause for severe neuropathy with limb weakness.
One hundred and eighty four patients with polyneuropathy associated with limb weakness underwent routine diagnostics including investigations for Sjögren's syndrome. Forty-four patients with Sjögren's syndrome (ACR-EULAR classification criteria) and severe neuropathy were identified.
Sjögren's syndrome was found at a median age of 63 years and the gender distribution showed a balanced female-male ratio of 1:1. Anti-SSA(Ro) antibodies were detected in 48% while seronegative patients were diagnosed with Sjögren's syndrome based on sialadenitis on minor salivary gland biopsy with a focus score ≥1. The majority of patients (93%) were diagnosed with Sjögren's syndrome after neurological symptoms appeared. Limbs were symmetrically involved in 84% of patients (57% tetraparesis, 27% paraparesis). Sensory function was not affected in 11% of patients indicating that Sjögren's syndrome associated neuropathy can present as a pure motor syndrome. Electrophysiological measurements did not reveal pathognomonic findings (23% demyelinating pattern, 36% axonal pattern, 41% both demyelinating and axonal damage signs). More than half of our patients fulfilled the European Federation of Neurological Societies (EFNS) diagnostic criteria for CIDP indicating that distinction between Neuro-Sjögren and other causes of neuropathy such as CIDP is challenging.
Our findings show that severe neuropathy with limb weakness is often associated with Sjögren's syndrome. This is of great importance in identifying and understanding the causes of immune mediated polyneuropathy.
Among others, expression of interferon-γ (IFNγ), interleukin (IL)-1β as well as other ILs, IL-2, IL-4, IL-8 and IL-10, chemokine (C-C motif) ligand 2, transforming growth factor β and tumor necrosis ...factor α was significantly increased in CD20+ T cells compared to CD20– T cells. ...CD20+ T cells constitute a small subset of ubiquitously distributed T cells with an increased proportion of cytotoxic CD8+ T cells, which represent a highly activated subpopulation with considerably enhanced cytokine production even during resting conditions. ...the subpopulation of CD20+ T cells has also been investigated in patients with MS. The CD4:CD8 ratio and the frequency of different subpopulations, e.g., naive, central memory, effector memory and memory T cells in the CD20+ T cell subset was comparable to the CD20+ T cell population in healthy controls (Palanichamy et al., 2014; von Essen et al., 2019). A considerably higher proportion of CD20+ T cells in peripheral blood displayed expression of chemokine receptors and adhesion molecules as C-C chemokine receptor type 2 (CCR2), CCR5, CCR6 or melanoma cell adhesion molecule 1 in RRMS patients as well as in healthy controls compared to CD20– T cells.
Crowdsourcing has been used in computational pathology to generate cell and cell nuclei annotations for machine learning. Herein, we broaden its scope to the previously unsolved challenging task of ...glioma cell detection. This requires multiplexed immunofluorescence microscopy due to diffuse invasiveness and exceptional similarity between glioma cells and reactive astrocytes. In four pilot experiments, we iteratively developed a task design enabling high-quality annotations by crowdworkers on Amazon Mechanical Turk. We applied majority or weighted vote and validated them against ground truth in the final setting. On the base of a YOLO convolutional neural network architecture, we used these consensus labels for training with different image representations regarding colors, intensities, and immmunohistochemical marker combinations. A crowd of 712 workers defined aggregated point annotations in 235 images with an average Formula: see text score of 0.627 for majority vote. The networks resulted in acceptable Formula: see text scores up to 0.69 for YOLOv8 on average and indicated first evidence for transferability to images lacking tumor markers, especially in IDH-wildtype glioblastoma. Our work confirms feasibility of crowdsourcing to generate labels suitable for training of machine learning tools in the challenging and clinically relevant use case of glioma microenvironment.
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