| 1. |
- Hanlon, Killian S., et al.
(författare)
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High levels of AAV vector integration into CRISPR-induced DNA breaks
- 2019
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Ingår i: Nature Communications. - : NATURE PUBLISHING GROUP. - 2041-1723. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Adeno-associated virus (AAV) vectors have shown promising results in preclinical models, but the genomic consequences of transduction with AAV vectors encoding CRISPR-Cas nucleases is still being examined. In this study, we observe high levels of AAV integration (up to 47%) into Cas9-induced double-strand breaks (DSBs) in therapeutically relevant genes in cultured murine neurons, mouse brain, muscle and cochlea. Genome-wide AAV mapping in mouse brain shows no overall increase of AAV integration except at the CRISPR/Cas9 target site. To allow detailed characterization of integration events we engineer a miniature AAV encoding a 465 bp lambda bacteriophage DNA (AAV-lambda 465), enabling sequencing of the entire integrated vector genome. The integration profile of AAV-465 lambda in cultured cells display both full-length and fragmented AAV genomes at Cas9 on-target sites. Our data indicate that AAV integration should be recognized as a common outcome for applications that utilize AAV for genome editing.
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| 2. |
- Lööv, Camilla, 1982-
(författare)
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Cellular and Molecular Responses to Traumatic Brain Injury
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Traumatic brain injury (TBI) is a relatively unknown disease considering the tens of millions of people affected around the world each year. Many TBI patients die from their injuries and survivors often suffer from life-long disabilities. The primary injury initiates a variety of cellular and molecular processes that are both beneficial and detrimental for the brain, but that are not fully understood. The focus of this thesis has been to study the role of astrocytes in clearance of dead cells after TBI and to identify injury specific proteins that may function as biomarkers, by using cell cultures, animal models and in cerebrospinal fluid (CSF) from TBI patients.The result demonstrates a new function in that astrocytes, the most numerous cell type in the brain, engulf dead cells after injury both in cell cultures and in adult mice and thereby save neurons from contact-induced apoptosis. Astrocytes are effective phagocytes, but degrade the ingested dead cells very slowly. Moreover, astrocytes express the lysosome-alkalizing proteins Rab27a and Nox2 as well as major histocompatibility complex class II, the receptors on which antigens are being presented. By lowering the pH of the lysosomes with acidic nanoparticles, the degradation increases, but the astrocytes still remained less effective than macrophages. Taken together, the data indicates that the low acidification in astrocytes can preserve antigens and that astrocytes may be able to activate T cells.The expression and secretion of injury-specific proteins was studied in a cell culture model of TBI by separate mass spectrometry analysis of cells and medium. Interestingly, close to 30 % of the injury-specific proteins in medium are linked to actin, for example ezrin of the ezrin/radixin/moesin (ERM) protein family. Ezrin, but none of the other ERM proteins or actin, is actively secreted after injury. Extracellular ezrin also increases in CSF in response to experimental TBI in rats and is present in CSF from TBI patients, indicating that ezrin is a potential biomarker for TBI.
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| 3. |
- Lööv, Camilla, 1982-, et al.
(författare)
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Extracellular Ezrin - a Novel Biomarker for Traumatic Brain Injury
- 2015
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Ingår i: Journal of Neurotrauma. - : Mary Ann Liebert Inc. - 0897-7151 .- 1557-9042. ; 32:4, s. 244-251
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Tidskriftsartikel (refereegranskat)abstract
- Traumatic brain injury (TBI) is a heterogeneous disease, and the discovery of diagnostic and prognostic TBI biomarkers is highly desirable in order to individualize patient care. We have previously published a study in which we identified possible TBI biomarkers by mass spectrometry 24 h after injury in a cell culture model. Ezrin-radixin-moesin (ERM) proteins were found abundantly in the medium after trauma, and in the present study we have identified extracellular ezrin as a possible biomarker for brain trauma by analyzing cell culture medium from injured primary neurons and glia and by measuring ezrin in cerebrospinal fluid (CSF) from both rats and humans. Our results show that extracellular ezrin concentration was substantially increased in cell culture medium after injury, but that the intracellular expression of the protein remained stable over time. Controlled cortical impact injured rats showed an increased amount of ezrin in CSF at both day 3 and day 7 after trauma. Moreover, ezrin was present in all ventricular CSF samples from seven humans with severe TBI. In contrast to intracellular ezrin, which is distinctly activated following TBI, extracellular ezrin is nonphosphorylated. This is the first report of extracellular ERM proteins in human and experimental models of TBI, providing a scientific foundation for further assessment of ezrin as a potential biomarker.
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| 4. |
- Lööv, Camilla, 1982-, et al.
(författare)
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Slow degradation in phagocytic astrocytes can be enhanced by lysosomal acidification
- 2015
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Ingår i: Glia. - : Wiley. - 0894-1491 .- 1098-1136. ; 63:11, s. 1997-2009
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Tidskriftsartikel (refereegranskat)abstract
- Inefficient lysosomal degradation is central in the development of various brain disorders, but the underlying mechanisms and the involvement of different cell types remains elusive. We have previously shown that astrocytes effectively engulf dead cells, but then store, rather than degrade the ingested material. In the present study we identify reasons for the slow digestion and ways to accelerate degradation in primary astrocytes. Our results show that actin-rings surround the phagosomes for long periods of time, which physically inhibit the phago-lysosome fusion. Furthermore, astrocytes express high levels of Rab27a, a protein known to reduce the acidity of lysosomes by Nox2 recruitment, in order to preserve antigens for presentation. We found that Nox2 colocalizes with the ingested material, indicating that it may influence antigen processing also in astrocytes, as they express MHC class II. By inducing long-time acidification of astrocytic lysosomes using acidic nanoparticles, we could increase the digestion of astrocyte-ingested, dead cells. The degradation was, however, normalized over time, indicating that inhibitory pathways are up-regulated in response to the enhanced acidification.
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