| 1. |
- Adori, Csaba, et al.
(författare)
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Disorganization and degeneration of liver sympathetic innervations in nonalcoholic fatty liver disease revealed by 3D imaging
- 2021
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Ingår i: Science Advances. - : American Association for the Advancement of Science (AAAS). - 2375-2548. ; 7:30
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Tidskriftsartikel (refereegranskat)abstract
- Hepatic nerves have a complex role in synchronizing liver metabolism. Here, we used three-dimensional (3D) immunoimaging to explore the integrity of the hepatic nervous system in experimental and human nonalcoholic fatty liver disease (NAFLD). We demonstrate parallel signs of mild degeneration and axonal sprouting of sympathetic innervations in early stages of experimental NAFLD and a collapse of sympathetic arborization in steatohepatitis. Human fatty livers display a similar pattern of sympathetic nerve degeneration, correlating with the severity of NAFLD pathology. We show that chronic sympathetic hyperexcitation is a key factor in the axonal degeneration, here genetically phenocopied in mice deficient of the Rac-1 activator Vav3. In experimental steatohepatitis, 3D imaging reveals a severe portal vein contraction, spatially correlated with the extension of the remaining nerves around the portal vein, enlightening a potential intrahepatic neuronal mechanism of portal hypertension. These fundamental alterations in liver innervation and vasculature uncover previously unidentified neuronal components in NAFLD pathomechanisms.
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| 2. |
- Barrefelt, Asa, et al.
(författare)
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Fluorescence labeled microbubbles for multimodal imaging
- 2015
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Ingår i: Biochemical and Biophysical Research Communications - BBRC. - : Elsevier BV. - 0006-291X .- 1090-2104. ; 464:3, s. 737-742
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Tidskriftsartikel (refereegranskat)abstract
- Air-filled polyvinyl alcohol microbubbles (PVA-MBs) were recently introduced as a contrast agent for ultrasound imaging. In the present study, we explore the possibility of extending their application in multimodal imaging by labeling them with a near infrared (NIR) fluorophore, VivoTag-680. PVA-MBs were injected intravenously into FVB/N female mice and their dynamic biodistribution over 24 h was determined by 3D-fluorescence imaging co-registered with 3D-mu CT imaging, to verify the anatomic location. To further confirm the biodistribution results from in vivo imaging, organs were removed and examined histologically using bright field and fluorescence microscopy. Fluorescence imaging detected PVA-MB accumulation in the lungs within the first 30 min post-injection. Redistribution to a low extent was observed in liver and kidneys at 4 h, and to a high extent mainly in the liver and spleen at 24 h. Histology confirmed PVA-MB localization in lung capillaries and macrophages. In the liver, they were associated with Kupffer cells; in the spleen, they were located mostly within the marginal-zone. Occasional MBs were observed in the kidney glomeruli and interstitium. The potential application of PVA-MBs as a contrast agent was also studied using ultrasound (US) imaging in subcutaneous and orthotopic pancreatic cancer mouse models, to visualize blood flow within the tumor mass. In conclusion, this study showed that PVA-MBs are useful as a contrast agent for multimodal imaging. (C) 2015 Elsevier Inc. All rights reserved.
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| 3. |
- Barrefelt, Åsa, et al.
(författare)
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Biodistribution, kinetics, and biological fate of SPION microbubbles in the rat
- 2013
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Ingår i: International Journal of Nanomedicine. - 1176-9114 .- 1178-2013. ; 8, s. 3241-3254
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Tidskriftsartikel (refereegranskat)abstract
- Background: In the present investigation, we studied the kinetics and biodistribution of a contrast agent consisting of poly(vinyl alcohol) (PVA) microbubbles containing superparamagnetic iron oxide (SPION) trapped between the PVA layers (SPION microbubbles). Methods: The biological fate of SPION microbubbles was determined in Sprague-Dawley rats after intravenous administration. Biodistribution and elimination of the microbubbles were studied in rats using magnetic resonance imaging for a period of 6 weeks. The rats were sacrificed and perfusion-fixated at different time points. The magnetic resonance imaging results obtained were compared with histopathologic findings in different organs. Results: SPION microbubbles could be detected in the liver using magnetic resonance imaging as early as 10 minutes post injection. The maximum signal was detected between 24 hours and one week post injection. Histopathology showed the presence of clustered SPION microbubbles predominantly in the lungs from the first time point investigated (10 minutes). The frequency of microbubbles declined in the pulmonary vasculature and increased in pulmonary, hepatic, and splenic macrophages over time, resulting in a relative shift from the lungs to the spleen and liver. Meanwhile, macrophages showed increasing signs of cytoplasmic iron accumulation, initially in the lungs, then followed by other organs. Conclusion: The present investigation highlights the biological behavior of SPION microbubbles, including organ distribution over time and indications for biodegradation. The present results are essential for developing SPION microbubbles as a potential contrast agent and/or a drug delivery vehicle for specific organs. Such a vehicle will facilitate the use of multimodality imaging techniques, including ultrasound, magnetic resonance imaging, and single positron emission computed tomography, and hence improve diagnostics, therapy, and the ability to monitor the efficacy of treatment.
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| 4. |
- Costa, Tânia D F, et al.
(författare)
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PAK4 suppresses RELB to prevent senescence-like growth arrest in breast cancer
- 2019
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 10:1, s. 1-18
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Tidskriftsartikel (refereegranskat)abstract
- Overcoming cellular growth restriction, including the evasion of cellular senescence, is a hallmark of cancer. We report that PAK4 is overexpressed in all human breast cancer subtypes and associated with poor patient outcome. In mice, MMTV-PAK4 overexpression promotes spontaneous mammary cancer, while PAK4 gene depletion delays MMTV-PyMT driven tumors. Importantly, PAK4 prevents senescence-like growth arrest in breast cancer cells in vitro, in vivo and ex vivo, but is not needed in non-immortalized cells, while PAK4 overexpression in untransformed human mammary epithelial cells abrogates H-RAS-V12-induced senescence. Mechanistically, a PAK4 - RELB - C/EBPβ axis controls the senescence-like growth arrest and a PAK4 phosphorylation residue (RELB-Ser151) is critical for RELB-DNA interaction, transcriptional activity and expression of the senescence regulator C/EBPβ. These findings establish PAK4 as a promoter of breast cancer that can overcome oncogene-induced senescence and reveal a selective vulnerability of cancer to PAK4 inhibition.
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| 5. |
- Frede, Annika, et al.
(författare)
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B cell expansion hinders the stroma-epithelium regenerative cross talk during mucosal healing
- 2022
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Ingår i: Immunity. - : Elsevier BV. - 1074-7613 .- 1097-4180. ; 55:12, s. 2336-
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Tidskriftsartikel (refereegranskat)abstract
- Therapeutic promotion of intestinal regeneration holds great promise, but defining the cellular mechanisms that influence tissue regeneration remains an unmet challenge. To gain insight into the process of mucosal healing, we longitudinally examined the immune cell composition during intestinal damage and regeneration. B cells were the dominant cell type in the healing colon, and single-cell RNA sequencing (scRNA-seq) re-vealed expansion of an IFN-induced B cell subset during experimental mucosal healing that predominantly located in damaged areas and associated with colitis severity. B cell depletion accelerated recovery upon injury, decreased epithelial ulceration, and enhanced gene expression programs associated with tissue re-modeling. scRNA-seq from the epithelial and stromal compartments combined with spatial transcriptomics and multiplex immunostaining showed that B cells decreased interactions between stromal and epithelial cells during mucosal healing. Activated B cells disrupted the epithelial-stromal cross talk required for orga-noid survival. Thus, B cell expansion during injury impairs epithelial-stromal cell interactions required for mucosal healing, with implications for the treatment of IBD.
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| 6. |
- Janssen, Annette B. G., et al.
(författare)
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Exploring, exploiting and evolving diversity of aquatic ecosystem models : a community perspective
- 2015
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Ingår i: Aquatic Ecology. - : Springer Science and Business Media LLC. - 1386-2588 .- 1573-5125. ; 49:4, s. 513-548
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Tidskriftsartikel (refereegranskat)abstract
- Here, we present a community perspective on how to explore, exploit and evolve the diversity in aquatic ecosystem models. These models play an important role in understanding the functioning of aquatic ecosystems, filling in observation gaps and developing effective strategies for water quality management. In this spirit, numerous models have been developed since the 1970s. We set off to explore model diversity by making an inventory among 42 aquatic ecosystem modellers, by categorizing the resulting set of models and by analysing them for diversity. We then focus on how to exploit model diversity by comparing and combining different aspects of existing models. Finally, we discuss how model diversity came about in the past and could evolve in the future. Throughout our study, we use analogies from biodiversity research to analyse and interpret model diversity. We recommend to make models publicly available through open-source policies, to standardize documentation and technical implementation of models, and to compare models through ensemble modelling and interdisciplinary approaches. We end with our perspective on how the field of aquatic ecosystem modelling might develop in the next 5-10 years. To strive for clarity and to improve readability for non-modellers, we include a glossary.
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| 7. |
- Shaker, Kian, et al.
(författare)
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Longitudinal In-Vivo X-Ray Fluorescence Computed Tomography With Molybdenum Nanoparticles
- 2020
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Ingår i: IEEE Transactions on Medical Imaging. - : Institute of Electrical and Electronics Engineers (IEEE). - 0278-0062 .- 1558-254X. ; 39:12, s. 3910-3919
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Tidskriftsartikel (refereegranskat)abstract
- X-ray fluorescence computed tomography (XFCT) with nanoparticles (NPs) as contrast agents shows potential for molecular biomedical imaging with higher spatial resolution than present methods. To date the technique has been demonstrated on phantoms and mice, however, parameters such as radiation dose, exposure times and sensitivity have not yet allowed for high-spatial-resolution in vivo longitudinal imaging, i.e., imaging of the same animal at different time points. Here we show in vivo XFCT with spatial resolution in the 200-400 mu m range in a proof-of-principle longitudinal study where mice are imaged five times each during an eight-week period following tail-vein injection of NPs. We rely on a 24 keV x-ray pencil-beam-based excitation of in-house-synthesized molybdenum oxide NPs (MoO2) to provide the high signal-to-background x-ray fluorescence detection necessary for XFCT imaging with low radiation dose and short exposure times. We quantify the uptake and clearance of NPs in vivo through imaging, and monitor animal well-being over the course of the study with support from histology and DNA stability analysis to assess the impact of x-ray exposure and NPs on animal welfare. We conclude that the presented imaging arrangement has potential for in vivo longitudinal studies, putting emphasis on designing biocompatible NPs as the future focus for active-targeting preclinical XFCT.
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| 8. |
- Tabor, Vedrana, et al.
(författare)
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MYC Synergizes with Activated BRAFV600E in Mouse Lung Tumor Development by Suppressing Senescence.
- 2014
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Ingår i: Cancer Research. - 1538-7445. ; 74:16, s. 4222-4229
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Tidskriftsartikel (refereegranskat)abstract
- The activated RAS/RAF cascade plays a crucial role in lung cancer, but is also known to induce cellular senescence - a major barrier imposed to tumor cells early in tumorigenesis. MYC is a key factor in suppression of RAS/BRAFV600E-induced senescence in vitro. However, it is still unclear whether Myc has the same role during tumor development in vivo. Using a conditional, compound knock-in model of Cre-activated BRAFV600E and tamoxifen (TAM)-regulatable MycER, we show that TAM-induced activation of MYC accelerated the onset and increased the number and size of BRAFV600E-driven adenomas in a dose dependent manner, resulting in reduced survival. Further, MYC activation lead to reduced expression of the senescence markers p16INK4A, p21CIP1 and H3K9me3-containing heterochromatin foci, and an increased percentage of Ki-67+ tumor cells. This suggests that MYC already early during tumor formation suppresses a BRAFV600E-induced senescence-like state. Initial activation of MYC followed by TAM withdrawal still resulted in an increased number of tumors and reduced survival. However, these tumors were of smaller size, showed increased expression of p16INK4A and p21CIP1 and reduced number of Ki-67+ cells, indicating that MYC inactivation restores BRAFV600E-induced senescence. Surprisingly, MYC activation did not promote adenoma to carcinoma progression. This suggests that senescence suppression by MYC is a discrete step in tumor development important for sustained tumor growth but preceding malignant transformation, and that additional oncogenic events are required for carcinoma development and metastasis. These findings contribute to our understanding of the neoplastic transformation process with implications for future treatment strategies.
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| 9. |
- Zerdes, Ioannis, et al.
(författare)
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Discordance of PD-L1 Expression at the Protein and RNA Levels in Early Breast Cancer
- 2021
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Ingår i: Cancers. - : MDPI. - 2072-6694. ; 13:18
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Tidskriftsartikel (refereegranskat)abstract
- Simple Summary Despite the increasing use of checkpoint inhibitors for early and metastatic breast cancer, Programmed Death Ligand 1 (PD-L1) remains the only validated albeit imperfect predictive biomarker. Significant discordance in PD-L1 protein expression depending on the antibody used has been demonstrated, while the weak correlation and discordant prognostic information between protein and gene expression underscore its biologic heterogeneity. In this study, we use material from two patient cohorts of early breast cancer and multiple methodologies (immunohistochemistry, RNA fluorescent in situ hybridization, immunofluorescence, bulk gene expression, and multiplex fluorescent immunohistochemistry) to demonstrate the significant discordance in PD-L1 expression among various methods and between different areas of the same tumor, which hints toward the presence of spatial, intratumoral and biological heterogeneity. We aimed to assess if the discrepant prognostic information between Programmed Death Ligand 1 (PD-L1) protein versus mRNA expression in early breast cancer (BC) could be attributed to heterogeneity in its expression. PD-L1 protein and mRNA expression in BC tissue microarrays from two clinical patient cohorts were evaluated (105 patients; cohort 1: untreated; cohort 2: neoadjuvant chemotherapy-treated). Immunohistochemistry (IHC) with SP142, SP263 was performed. PD-L1 mRNA was evaluated using bulk gene expression and RNA-FISH RNAscope, the latter scored in a semi-quantitative manner and combined with immunofluorescence (IF) staining for the simultaneous detection of PD-L1 protein expression. PD-L1 expression was assessed in cores as a whole and in two regions of interest (ROI) from the same core. The cell origin of PD-L1 expression was evaluated using multiplex fluorescent IHC. IHC PD-L1 expression between SP142 and SP263 was concordant in 86.7% of cores (p < 0.001). PD-L1 IF/IHC was weakly correlated with spatial mRNA expression (concordance 54.6-71.2%). PD-L1 was mostly expressed by lymphocytes intra-tumorally, while its stromal expression was mostly observed in macrophages. Our results demonstrate only moderate concordance between the various methods of assessing PD-L1 expression at the protein and mRNA levels, which may be attributed to both analytical performance and spatial heterogeneity.
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