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| 2. |
- Alexander, Jes, et al.
(författare)
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Multimodal single-cell analysis reveals distinct radioresistant stem-like and progenitor cell populations in murine glioma
- 2020
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Ingår i: GLIA. - : Wiley. - 0894-1491 .- 1098-1136. ; 68:12, s. 2486-2502
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Tidskriftsartikel (refereegranskat)abstract
- Radiation therapy is part of the standard of care for gliomas and kills a subset of tumor cells, while also altering the tumor microenvironment. Tumor cells with stem-like properties preferentially survive radiation and give rise to glioma recurrence. Various techniques for enriching and quantifying cells with stem-like properties have been used, including the fluorescence activated cell sorting (FACS)-based side population (SP) assay, which is a functional assay that enriches for stem-like tumor cells. In these analyses, mouse models of glioma have been used to understand the biology of this disease and therapeutic responses, including the radiation response. We present combined SP analysis and single-cell RNA sequencing of genetically-engineered mouse models of glioma to show a time course of cellular response to radiation. We identify and characterize two distinct tumor cell populations that are inherently radioresistant and also distinct effects of radiation on immune cell populations within the tumor microenvironment.
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| 7. |
- Goncalves, Nadia P., et al.
(författare)
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Schwann cell p75 neurotrophin receptor modulates small fiber degeneration in diabetic neuropathy
- 2020
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Ingår i: Glia. - : WILEY. - 0894-1491 .- 1098-1136. ; 68:12, s. 2725-2743
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Tidskriftsartikel (refereegranskat)abstract
- Diabetic neuropathy has an incidence as high as 50% of diabetic patients and is characterized by damage to neurons, Schwann cells and blood vessels within the peripheral nervous system. The low-affinity neurotrophin receptor p75 (p75(NTR)), particularly expressed by the Schwann cells in the peripheral nerve, has previously been reported to play a role in developmental myelination and cell survival/death. Increased levels of p75(NTR), in the endoneurium and plasma from diabetic patients and rodent models of disease, have been observed, proposing that this receptor might be involved in the pathogenesis of diabetic neuropathy. Therefore, in this study, we addressed this hypothesis by utilizing a mouse model of selective nerve growth factor receptor (Ngfr) deletion in Schwann cells (SC-p75(NTR)-KO). Electron microscopy of sciatic nerves from mice with high fat diet induced obesity demonstrated how loss of Schwann cell-p75(NTR)aggravated axonal atrophy and loss of C-fibers. RNA sequencing disclosed several pre-clinical signaling alterations in the diabetic peripheral nerves, dependent on Schwann cell p75(NTR)signaling, specially related with lysosome, phagosome, and immune pathways. Morphological and biochemical analyses identified abundant lysosomes and autophagosomes in the C-fiber axoplasm of the diabetic SC-p75(NTR)-KO nerves, which together with increased Cathepsin B protein levels corroborates gene upregulation from the phagolysosomal pathways. Altogether, this study demonstrates that Schwann cell p75(NTR)deficiency amplifies diabetic neuropathy disease by triggering overactivation of immune-related pathways and increased lysosomal stress.
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| 9. |
- Kaplan, Lew, et al.
(författare)
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Retinal regions shape human and murine Müller cell proteome profile and functionality
- 2023
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Ingår i: GLIA. - : Wiley. - 0894-1491 .- 1098-1136. ; 71:2, s. 391-414
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Tidskriftsartikel (refereegranskat)abstract
- The human macula is a highly specialized retinal region with pit-like morphology and rich in cones. How Müller cells, the principal glial cell type in the retina, are adapted to this environment is still poorly understood. We compared proteomic data from cone- and rod-rich retinae from human and mice and identified different expression profiles of cone- and rod-associated Müller cells that converged on pathways representing extracellular matrix and cell adhesion. In particular, epiplakin (EPPK1), which is thought to play a role in intermediate filament organization, was highly expressed in macular Müller cells. Furthermore, EPPK1 knockout in a human Müller cell-derived cell line led to a decrease in traction forces as well as to changes in cell size, shape, and filopodia characteristics. We here identified EPPK1 as a central molecular player in the region-specific architecture of the human retina, which likely enables specific functions under the immense mechanical loads in vivo.
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| 11. |
- Leiss, Lina, et al.
(författare)
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Platelet-derived growth factor receptor α/glial fibrillary acidic protein expressing peritumoral astrocytes associate with shorter median overall survival in glioblastoma patients.
- 2020
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Ingår i: Glia. - : Wiley. - 0894-1491 .- 1098-1136. ; 68:5, s. 979-988
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Tidskriftsartikel (refereegranskat)abstract
- The microenvironment and architecture of peritumoral tissue have been suggested to affect permissiveness for infiltration of malignant cells. Astrocytes constitute a heterogeneous population of cells and have been linked to proliferation, migration, and drug sensitivity of glioblastoma (GBM) cells. Through double-immunohistochemical staining for platelet-derived growth factor receptor α (PDGFRα) and glial fibrillary acidic protein (GFAP), this study explored the intercase variability among 45 human GBM samples regarding density of GFAP+ peritumoral astrocytes and a subset of GFAP+ peritumoral astrocyte-like cells also expressing PDGFRα. Large intercase variability regarding the total peritumoral astrocyte density and the density of PDGFRα+/GFAP+ peritumoral astrocyte-like cells was detected. DNA fluorescence in situ hybridization analyses for commonly altered genetic tumor markers supported the interpretation that these cells represented a genetically unaffected host cell subset referred to as PDGFRα+/GFAP+ peritumoral astrocytes. The presence of PDGFRα+/GFAP+ peritumoral astrocytes was significantly positively correlated to older patient age and peritumoral astrocyte density, but not to other established prognostic factors. Notably, presence of PDGFRα+/GFAP+ peritumoral astrocytes, but not peritumoral astrocyte density, was associated with significantly shorter patient overall survival. The prognostic association of PDGFRα+/GFAP+ peritumoral astrocytes was confirmed in multivariable analyses. This exploratory study thus demonstrates previously unrecognized intercase variability and prognostic significance of peritumoral abundance of a novel PDGFRα+ subset of GFAP+ astrocytes. Findings suggest clinically relevant roles of the microenvironment of peritumoral GBM tissue and encourage further characterization of the novel astrocyte subset with regard to origin, function, and potential as biomarker and drug target.
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| 12. |
- Maturi, Naga Prathyusha, et al.
(författare)
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A molecularly distinct subset of glioblastoma requires serum-containing media to establish sustainable bona fide glioblastoma stem cell cultures
- 2020
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Ingår i: Glia. - : Wiley. - 0894-1491 .- 1098-1136. ; 68:6, s. 1228-1240
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Tidskriftsartikel (refereegranskat)abstract
- Glioblastoma (GBM) is the most frequent and deadly primary malignant brain tumor. Hallmarks are extensive intra-tumor and inter-tumor heterogeneity and highly invasive growth, which provide great challenges for treatment. Efficient therapy is lacking and the majority of patients survive less than 1 year from diagnosis. GBM progression and recurrence is caused by treatment-resistant glioblastoma stem cells (GSCs). GSC cultures are considered important models in target identification and drug screening studies. The current state-of-the-art method, to isolate and maintain GSC cultures that faithfully mimic the primary tumor, is to use serum-free (SF) media conditions developed for neural stem cells (NSCs). Here we have investigated the outcome of explanting 218 consecutively collected GBM patient samples under both SF and standard, serum-containing media conditions. The frequency of maintainable SF cultures (SFCs) was most successful, but for a subgroup of GBM specimens, a viable culture could only be established in serum-containing media, called exclusive serum culture (ESC). ESCs expressed nestin and SOX2, and displayed all functional characteristics of a GSC, that is, extended proliferation, sustained self-renewal and orthotopic tumor initiation. Once adapted to the in vitro milieu they were also sustainable in SF media. Molecular analyses showed that ESCs formed a discrete group that was most related to the mesenchymal GBM subtype. This distinct subgroup of GBM that would have evaded modeling in SF conditions only provide unique cell models of GBM inter-tumor heterogeneity.
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| 13. |
- Mega, Alessandro, et al.
(författare)
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Astrocytes enhance glioblastoma growth.
- 2020
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Ingår i: Glia. - : Wiley. - 0894-1491 .- 1098-1136. ; 68:2, s. 316-327
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Tidskriftsartikel (refereegranskat)abstract
- Glioblastoma (GBM) is a deadly disease with a need for deeper understanding and new therapeutic approaches. The microenvironment of glioblastoma has previously been shown to guide glioblastoma progression. In this study, astrocytes were investigated with regard to their effect on glioblastoma proliferation through correlative analyses of clinical samples and experimental in vitro and in vivo studies. Co-culture techniques were used to investigate the GBM growth enhancing potential of astrocytes. Cell sorting and RNA sequencing were used to generate a GBM-associated astrocyte signature and to investigate astrocyte-induced GBM genes. A NOD scid GBM mouse model was used for in vivo studies. A gene signature reflecting GBM-activated astrocytes was associated with poor prognosis in the TCGA GBM dataset. Two genes, periostin and serglycin, induced in GBM cells upon exposure to astrocytes were expressed at higher levels in cases with high "astrocyte signature score". Astrocytes were shown to enhance glioblastoma cell growth in cell lines and in a patient-derived culture, in a manner dependent on cell-cell contact and involving increased cell proliferation. Furthermore, co-injection of astrocytes with glioblastoma cells reduced survival in an orthotopic GBM model in NOD scid mice. In conclusion, this study suggests that astrocytes contribute to glioblastoma growth and implies this crosstalk as a candidate target for novel therapies.
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| 14. |
- Michalettos, Georgios, et al.
(författare)
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Impaired oligodendrogenesis in the white matter of aged mice following diffuse traumatic brain injury
- 2024
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Ingår i: GLIA. - : John Wiley & Sons. - 0894-1491 .- 1098-1136.
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Tidskriftsartikel (refereegranskat)abstract
- Senescence is a negative prognostic factor for outcome and recovery following traumatic brain injury (TBI). TBI-induced white matter injury may be partially due to oligodendrocyte demise. We hypothesized that the regenerative capacity of oligodendrocyte precursor cells (OPCs) declines with age. To test this hypothesis, the regenerative capability of OPCs in young [(10 weeks ±2 (SD)] and aged [(62 weeks ±10 (SD)] mice was studied in mice subjected to central fluid percussion injury (cFPI), a TBI model causing widespread white matter injury. Proliferating OPCs were assessed by immunohistochemistry for the proliferating cell nuclear antigen (PCNA) marker and labeled by 5-ethynyl-2′-deoxyuridine (EdU) administered daily through intraperitoneal injections (50 mg/kg) from day 2 to day 6 after cFPI. Proliferating OPCs were quantified in the corpus callosum and external capsule on day 2 and 7 post-injury (dpi). The number of PCNA/Olig2-positive and EdU/Olig2-positive cells were increased at 2dpi (p <.01) and 7dpi (p <.01), respectively, in young mice subjected to cFPI, changes not observed in aged mice. Proliferating Olig2+/Nestin+ cells were less common (p <.05) in the white matter of brain-injured aged mice, without difference in proliferating Olig2+/PDGFRα+ cells, indicating a diminished proliferation of progenitors with different spatial origin. Following TBI, co-staining for EdU/CC1/Olig2 revealed a reduced number of newly generated mature oligodendrocytes in the white matter of aged mice when compared to the young, brain-injured mice (p <.05). We observed an age-related decline of oligodendrogenesis following experimental TBI that may contribute to the worse outcome of elderly patients following TBI.
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| 15. |
- Oksanen, Minna, et al.
(författare)
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NF-E2-related factor 2 activation boosts antioxidant defenses and ameliorates inflammatory and amyloid properties in human Presenilin-1 mutated Alzheimer's disease astrocytes
- 2020
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Ingår i: GLIA. - : Wiley. - 0894-1491 .- 1098-1136. ; 68:3, s. 589-599
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Tidskriftsartikel (refereegranskat)abstract
- Alzheimer's disease (AD) is a common dementia affecting a vast number of individuals and significantly impairing quality of life. Despite extensive research in animal models and numerous promising treatment trials, there is still no curative treatment for AD. Astrocytes, the most common cell type of the central nervous system, have been shown to play a role in the major AD pathologies, including accumulation of amyloid plaques, neuroinflammation, and oxidative stress. Here, we show that inflammatory stimulation leads to metabolic activation of human astrocytes and reduces amyloid secretion. On the other hand, the activation of oxidative metabolism leads to increased reactive oxygen species production especially in AD astrocytes. While healthy astrocytes increase glutathione (GSH) release to protect the cells, Presenilin-1-mutated AD patient astrocytes do not. Thus, chronic inflammation is likely to induce oxidative damage in AD astrocytes. Activation of NRF2, the major regulator of cellular antioxidant defenses, encoded by the NFE2L2 gene, poses several beneficial effects on AD astrocytes. We report here that the activation of NRF2 pathway reduces amyloid secretion, normalizes cytokine release, and increases GSH secretion in AD astrocytes. NRF2 induction also activates the metabolism of astrocytes and increases the utilization of glycolysis. Taken together, targeting NRF2 in astrocytes could be a potent therapeutic strategy in AD.
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| 16. |
- Peteri, Ulla Kaisa, et al.
(författare)
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Urokinase plasminogen activator mediates changes in human astrocytes modeling fragile X syndrome
- 2021
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Ingår i: GLIA. - : Wiley. - 0894-1491 .- 1098-1136. ; 69:12, s. 2947-2962
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Tidskriftsartikel (refereegranskat)abstract
- The function of astrocytes intertwines with the extracellular matrix, whose neuron and glial cell-derived components shape neuronal plasticity. Astrocyte abnormalities have been reported in the brain of the mouse model for fragile X syndrome (FXS), the most common cause of inherited intellectual disability, and a monogenic cause of autism spectrum disorder. We compared human FXS and control astrocytes generated from human induced pluripotent stem cells and we found increased expression of urokinase plasminogen activator (uPA), which modulates degradation of extracellular matrix. Several pathways associated with uPA and its receptor function were activated in FXS astrocytes. Levels of uPA were also increased in conditioned medium collected from FXS hiPSC-derived astrocyte cultures and correlated inversely with intracellular Ca2+ responses to activation of L-type voltage-gated calcium channels in human astrocytes. Increased uPA augmented neuronal phosphorylation of TrkB within the docking site for the phospholipase-Cγ1 (PLCγ1), indicating effects of uPA on neuronal plasticity. Gene expression changes during neuronal differentiation preceding astrogenesis likely contributed to properties of astrocytes with FXS-specific alterations that showed specificity by not affecting differentiation of adenosine triphosphate (ATP)-responsive astrocyte population. To conclude, our studies identified uPA as an important regulator of astrocyte function and demonstrated that increased uPA in human FXS astrocytes modulated astrocytic responses and neuronal plasticity.
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| 17. |
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| 18. |
- Venero, J. L., et al.
(författare)
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ARG1 expression in basal forebrain microglia modulates hippocampal innervation and cognition during postnatal development
- 2023
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Ingår i: Glia. - : John Wiley & Sons. - 0894-1491 .- 1098-1136. ; 71:Suppl. 1, s. E512-E512
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Diversity within microglia, the resident brain immune cells, is reported. Whether microglial subsets constitute different subtypes with intrinsic properties and unique functions has not been fully elucidated. Here, we describe a microglial subtype characterized by the expression of the enzyme Arginase-1, i.e.Arg1+microglia, which is found predominantly in the cholinergic neuron-rich forebrain region during early postnatal development. Arg1+microgliacontain cellular inclusions and exhibit a distinct molecular signature including upregulation of genes such as Apoe, Clec7a, Igf1, Lgals3and Mgl2. Arg1-knockout in microglia results in a deficient cholinergic innervation along with impaired dendritic spine maturation in the hippocampus where cholinergic neurons project, impaired long-term potentiation and cognitive behavioural deficiencies in female mice. Our results expand on microglia diversity and provide insights into distinctive spatiotemporal functions exerted by microglial subtypes.
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| 19. |
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| 20. |
- Zheng, Tianyu, et al.
(författare)
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Characterization of reduced astrocyte creatine kinase levels in Alzheimer's disease
- 2024
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Ingår i: Glia. - : WILEY. - 0894-1491 .- 1098-1136.
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Tidskriftsartikel (refereegranskat)abstract
- The creatine-phosphocreatine cycle serves as a crucial temporary energy buffering system in the brain, regulated by brain creatine kinase (CKB), in maintaining Adenosine triphosphate (ATP) levels. Alzheimer's disease (AD) has been linked to increased CKB oxidation and loss of its regulatory function, although specific pathological processes and affected cell types remain unclear. In our study, cerebral cortex samples from individuals with AD, dementia with Lewy bodies (DLB), and age-matched controls were analyzed using antibody-based methods to quantify CKB levels and assess alterations associated with disease processes. Two independently validated antibodies exclusively labeled astrocytes in the human cerebral cortex. Combining immunofluorescence (IF) and mass spectrometry (MS), we explored CKB availability in AD and DLB cases. IF and Western blot analysis demonstrated a loss of CKB immunoreactivity correlated with increased plaque load, severity of tau pathology, and Lewy body pathology. However, transcriptomics data and targeted MS demonstrated unaltered total CKB levels, suggesting posttranslational modifications (PTMs) affecting antibody binding. This aligns with altered efficiency at proteolytic cleavage sites indicated in the targeted MS experiment. These findings highlight that the proper function of astrocytes, understudied in the brain compared with neurons, is highly affected by PTMs. Reduction in ATP levels within astrocytes can disrupt ATP-dependent processes, such as the glutamate-glutamine cycle. As CKB and the creatine-phosphocreatine cycle are important in securing constant ATP availability, PTMs in CKB, and astrocyte dysfunction may disturb homeostasis, driving excitotoxicity in the AD brain. CKB and its activity could be promising biomarkers for monitoring early-stage energy deficits in AD. Brain creatine kinase (CKB) mainly expressed in strocytes in the human brain. A loss of CKB immunoreactivity correlated with increased plaque load. CKB antibody binding might be affected by posttranslational modifications. image
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