| 1. |
- de Oliveira, Kelin Gonçalves, et al.
(författare)
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Decoding of the surfaceome and endocytome in primary glioblastoma cells identifies potential target antigens in the hypoxic tumor niche
- 2024
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Ingår i: Acta Neuropathologica Communications. - : BioMed Central (BMC). - 2051-5960. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- Immunotherapies with antibody-drug-conjugates (ADC) and CAR-T cells, targeted at tumor surface antigens (surfaceome), currently revolutionize clinical oncology. However, target identification warrants a better understanding of the surfaceome and how it is modulated by the tumor microenvironment. Here, we decode the surfaceome and endocytome and its remodeling by hypoxic stress in glioblastoma (GBM), the most common and aggressive brain tumor in adults. We employed a comprehensive approach for global and dynamic profiling of the surfaceome and endocytosed (endocytome) proteins and their regulation by hypoxia in patient-derived GBM cultures. We found a heterogeneous surface-endocytome profile and a divergent response to hypoxia across GBM cultures. We provide a quantitative ranking of more than 600 surface resident and endocytosed proteins, and their regulation by hypoxia, serving as a resource to the cancer research community. As proof-of-concept, the established target antigen CD44 was identified as a commonly and abundantly expressed surface protein with high endocytic activity. Among hypoxia induced proteins, we reveal CXADR, CD47, CD81, BSG, and FXYD6 as potential targets of the stressed GBM niche. We could validate these findings by immunofluorescence analyses in patient tumors and by increased expression in the hypoxic core of GBM spheroids. Selected candidates were finally confronted by treatment studies, showing their high capacity for internalization and ADC delivery. Importantly, we highlight the limited correlation between transcriptomics and proteomics, emphasizing the critical role of membrane protein enrichment strategies and quantitative mass spectrometry. Our findings provide a comprehensive understanding of the surface-endocytome and its remodeling by hypoxia in GBM as a resource for exploration of targets for immunotherapeutic approaches in GBM.
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| 2. |
- Governa, Valeria, et al.
(författare)
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Landscape of surfaceome and endocytome in human glioma is divergent and depends on cellular spatial organization
- 2022
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences (PNAS). - 0027-8424 .- 1091-6490. ; 119:9
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Tidskriftsartikel (refereegranskat)abstract
- Therapeutic strategies directed at the tumor surfaceome (TS), including checkpoint inhibitor blocking antibodies, antibody drug conjugates (ADCs), and chimeric antigen receptor T (CAR-T) cells, provide a new armament to fight cancer. However, a remaining bottleneck is the lack of strategies to comprehensively interrogate patient tumors for potential TS targets. Here, we have developed a platform (tumor surfaceome mapping [TS-MAP]) integrated with a newly curated TS classifier (SURFME) that allows profiling of primary 3D cultures and intact patient glioma tumors with preserved tissue architecture. Moreover, TS-MAP specifically identifies proteins capable of endocytosis as tractable targets for ADCs and other modalities requiring toxic payload internalization. In high-grade gliomas that remain among the most aggressive forms of cancer, we show that cellular spatial organization (2D vs. 3D) fundamentally transforms the surfaceome and endocytome (e.g., integrins, proteoglycans, semaphorins, and cancer stem cell markers) with general implications for target screening approaches, as exemplified by an ADC targeting EGFR. The TS-MAP platform was further applied to profile the surfaceome and endocytome landscape in a cohort of freshly resected gliomas. We found a highly diverse TS repertoire between patient tumors, not directly associated with grade and histology, which highlights the need for individualized approaches. Our data provide additional layers of understanding fundamental to the future development of immunotherapy strategies, as well as procedures for proteomics-based target identification and selection. The TS-MAP platform should be widely applicable in efforts aiming at a better understanding of how to harness the TS for personalized immunotherapy.
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| 3. |
- Hellsten, Johan, et al.
(författare)
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Electroconvulsive seizures increase hippocampal neurogenesis after chronic corticosterone treatment
- 2002
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Ingår i: European Journal of Neuroscience. - : Wiley. - 1460-9568 .- 0953-816X. ; 16:2, s. 283-290
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Tidskriftsartikel (refereegranskat)abstract
- Major depression is often associated with elevated glucocorticoid levels. High levels of glucocorticoids reduce neurogenesis in the adult rat hippocampus. Electroconvulsive seizures (ECS) can enhance neurogenesis, and we investigated the effects of ECS in rats where glucocorticoid levels were elevated in order to mimic conditions seen in depression. Rats given injections of corticosterone or vehicle for 21 days were at the end of this period treated with either a single or five daily ECSs. Proliferating cells were labelled with bromodeoxyuridine (BrdU). After 3 weeks, BrdU-positive cells in the dentate gyrus were quantified and analyzed for co-labelling with the neuronal marker neuron-specific nuclear protein (NeuN). In corticosterone-treated rats, neurogenesis was decreased by 75%. This was counteracted by a single ECS. Multiple ECS further increased neurogenesis and no significant differences in BrdU/NeuN positive cells were detected between corticosterone- and vehicle-treated rats given five ECS. Approximately 80% of the cells within the granule cell layer and 10% of the hilar cells were double-labelled with BrdU and NeuN. We therefore conclude that electroconvulsive seizures can increase hippocampal neurogenesis even in the presence of elevated levels of glucocorticoids. This further supports the hypothesis that induction of neurogenesis is an important event in the action of antidepressant treatment.
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| 4. |
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| 5. |
- Petri, Rebecca, et al.
(författare)
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LINE-2 transposable elements are a source of functional human microRNAs and target sites
- 2019
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Ingår i: PLoS Genetics. - : Public Library of Science (PLoS). - 1553-7404. ; 15:3, s. 1008036-1008036
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Tidskriftsartikel (refereegranskat)abstract
- Transposable elements (TEs) are dynamically expressed at high levels in multiple human tissues, but the function of TE-derived transcripts remains largely unknown. In this study, we identify numerous TE-derived microRNAs (miRNAs) by conducting Argonaute2 RNA immunoprecipitation followed by small RNA sequencing (AGO2 RIP-seq) on human brain tissue. Many of these miRNAs originated from LINE-2 (L2) elements, which entered the human genome around 100-300 million years ago. L2-miRNAs derived from the 3' end of the L2 consensus sequence and thus shared very similar sequences, indicating that L2-miRNAs could target transcripts with L2s in their 3'UTR. In line with this, many protein-coding genes carried fragments of L2-derived sequences in their 3'UTR: these sequences served as target sites for L2-miRNAs. L2-miRNAs and their targets were generally ubiquitously expressed at low levels in multiple human tissues, suggesting a role for this network in buffering transcriptional levels of housekeeping genes. In addition, we also found evidence that this network is perturbed in glioblastoma. In summary, our findings uncover a TE-based post-transcriptional network that shapes transcriptional regulation in human cells.
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| 6. |
- Andersson, My, et al.
(författare)
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Optogenetic control of human neurons in organotypic brain cultures
- 2016
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- Optogenetics is one of the most powerful tools in neuroscience, allowing for selective control of specific neuronal populations in the brain of experimental animals, including mammals. We report, for the first time, the application of optogenetic tools to human brain tissue providing a proof-of-concept for the use of optogenetics in neuromodulation of human cortical and hippocampal neurons as a possible tool to explore network mechanisms and develop future therapeutic strategies.
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| 7. |
- Avaliani, Natalia, et al.
(författare)
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Optogenetics reveal delayed afferent synaptogenesis on grafted human induced pluripotent stem cell-derived neural progenitors.
- 2014
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Ingår i: Stem Cells. - : Oxford University Press (OUP). - 1549-4918 .- 1066-5099. ; 32:12, s. 3088-3098
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Tidskriftsartikel (refereegranskat)abstract
- Reprogramming of somatic cells into pluripotency stem cell state have opened new opportunities in cell replacement therapy and disease modeling in a number of neurological disorders. It still remains unknown, however, to what degree the grafted human induced pluripotent stem cells (hiPSCs) differentiate into a functional neuronal phenotype and if they integrate into the host circuitry. Here we present a detailed characterization of the functional properties and synaptic integration of hiPSC-derived neurons grafted in an in vitro model of hyperexcitable epileptic tissue, namely organotypic hippocampal slice cultures (OHSC), and in adult rats in vivo. The hiPSCs were first differentiated into long-term self-renewing neuroepithelial stem (lt-NES) cells, which are known to form primarily GABAergic neurons. When differentiated in OHSCs for six weeks, lt-NES cell-derived neurons displayed neuronal properties such as TTX-sensitive sodium currents and action potentials (APs), as well as both spontaneous and evoked postsynaptic currents, indicating functional afferent synaptic inputs. The grafted cells had a distinct electrophysiological profile compared to host cells in the OHSCs with higher input resistance, lower resting membrane potential and APs with lower amplitude and longer duration. To investigate the origin of synaptic afferents to the grafted lt-NES cell-derived neurons, the host neurons were transduced with Channelrhodopsin-2 (ChR2) and optogenetically activated by blue light. Simultaneous recordings of synaptic currents in grafted lt-NES cell-derived neurons using whole-cell patch-clamp technique at 6 weeks after grafting revealed limited synaptic connections from host neurons. Longer differentiation times, up to 24 weeks after grafting in vivo, revealed more mature intrinsic properties and extensive synaptic afferents from host neurons to the It-NES cell-derived neurons, suggesting that these cells require extended time for differentiation/maturation and synaptogenesis. However, even at this later time-point, the grafted cells maintained a higher input resistance. These data indicate that grafted lt-NES cell-derived neurons receive ample afferent input from the host brain. Since the lt-NES cells used in this study show a strong propensity for GABAergic differentiation, the host-to-graft synaptic afferents may facilitate inhibitory neurotransmitter release, and normalize hyperexcitable neuronal networks in brain diseases, e.g. such as epilepsy. Stem Cells 2014.
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| 8. |
- Bengzon, Johan, et al.
(författare)
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Apoptosis and proliferation of dentate gyrus neurons after single and intermittent limbic seizures
- 1997
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Ingår i: Proceedings of the National Academy of Sciences. - 1091-6490. ; 94:19, s. 10432-10437
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Tidskriftsartikel (refereegranskat)abstract
- Neuronal apoptosis was observed in the rat dentate gyrus in two experimental models of human limbic epilepsy. Five hours after one hippocampal kindling stimulation, a marked increase of in situ terminal deoxynucleotidyltransferase-mediated dUTP nick-end labeling (TUNEL) of fragmented DNA was observed in nuclei located within and on the hilar border of the granule cell layer and in the polymorphic region. Forty kindling stimulations with 5-min interval produced higher numbers of labeled nuclei compared with one stimulation. The increase of TUNEL-positive nuclei was prevented by the protein synthesis inhibitor cycloheximide but not affected by the N-methyl-D-aspartate receptor antagonist MK-801. Kainic acid-induced seizures lead to a pattern of labeling in the hippocampal formation identical to that evoked by kindling. A large proportion of cells displaying TUNEL-positive nuclei was double-labeled by the neuron-specific antigen NeuN, demonstrating the neuronal identity of apoptotic cells. Either 1 or 40 kindling stimulations also gave rise to a marked increase of the number of cells double-labeled with the mitotic marker bromodeoxyuridine and NeuN in the subgranular zone and on the hilar border of the dentate granule cell layer. The present data show that single and intermittent, brief seizures induce both apoptotic death and proliferation of dentate gyrus neurons. We hypothesize that these processes, occurring early during epileptogenesis, are primary events in the development of hippocampal pathology in animals and possibly also in patients suffering from temporal lobe epilepsy.
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| 9. |
- Bengzon, Johan, et al.
(författare)
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C-reactive protein levels following standard neurosurgical procedures
- 2003
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Ingår i: Acta Neurochirurgica. - : Springer Science and Business Media LLC. - 0001-6268 .- 0942-0940. ; 145:8, s. 667-671
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Tidskriftsartikel (refereegranskat)abstract
- Background. The aim of the present study was to establish the magnitude and time-course of C-reactive protein increases following routine neurosurgical procedures in the absence of clinical and laboratory signs of infection. Method. C-reactive protein levels were studied daily following ventriculo-peritoneal shunt implantation, anterior cervical fusion, vestibular schwannoma operation, supratentorial glioma surgery, endovascular intracranial aneurysm treatment and open cerebral aneurysm surgery. Findings. The magnitude of the C-reactive protein increase depended on the extent of surgical trauma and peak-levels were recorded between postoperative day one and four after which the levels tapered off. Interpretation. Increases occur-ring after the fourth postoperative day are likely to be caused by complications of surgery, e.g. infection.
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| 10. |
- Bengzon, Johan, et al.
(författare)
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Neuronal apoptosis after brief and prolonged seizures
- 2002
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Ingår i: Progress in Brain Research. - 1875-7855. ; 135, s. 111-119
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Forskningsöversikt (refereegranskat)abstract
- Evidence has accumulated that apoptotic cell death contributes to brain damage following experimental seizures. A substantial number of degenerating neurons within limbic regions display morphological features of apoptosis following prolonged seizures evoked by systemic or local injections of kainic acid, systemic injections of pilocarpine and sustained stimulation of the perforant path. Although longer periods of seizures consistently result in brain damage, it has previously not been clear whether brief single or intermittent seizures lead to cell death. However, recent results indicate that also single seizures lead to apoptotic neuronal death. A brief, non-convulsive seizure evoked by kindling stimulation was found to produce apoptotic neurons bilaterally in the rat dentate gyrus. The mechanism triggering and mediating apoptotic degeneration is at present being studied. Alterations in the expression and activity of cell-death regulatory proteins such as members of the Bcl-2 family and the cysteinyl aspartate-specific proteinase (caspase) family occur in regions vulnerable to cell degeneration, suggesting an involvement of these factors in mediating apoptosis following seizures. Findings of decreased apoptotic cell death following administration of caspase inhibitors prior to and following experimentally induced status epilepticus, further suggest a role for caspases in seizure-evoked neuronal degeneration. Intermediate forms of cell death with both necrotic and apoptotic features have been found after seizures and investigation into the detailed mechanisms of the different forms of cell degeneration is needed before attempts to specific prevention can be made.
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