| 1. |
- Eberhardt, F., et al.
(författare)
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A Uniform and Isotropic Cytoskeletal Tiling Fills Dendritic Spines
- 2022
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Ingår i: eNeuro. - : Society for Neuroscience. - 2373-2822. ; 9:5
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Tidskriftsartikel (refereegranskat)abstract
- Dendritic spines are submicron, subcellular compartments whose shape is defined by actin filaments and associated proteins. Accurately mapping the cytoskeleton is a challenge, given the small size of its components. It remains unclear whether the actin-associated structures analyzed in dendritic spines of neurons in vitro apply to dendritic spines of intact, mature neurons in situ. Here, we combined advanced preparative methods with multitilt serial section electron microscopy (EM) tomography and computational analysis to reveal the full three-dimensional (3D) internal architecture of spines in the intact brains of male mice at nanometer resolution. We compared hippocampal (CA1) pyramidal cells and cerebellar Purkinje cells in terms of the length distribution and connectivity of filaments, their branching-angles and absolute orientations, and the elementary loops formed by the network. Despite differences in shape and size across spines and between spine heads and necks, the internal organization was remarkably similar in both neuron types and largely homogeneous throughout the spine volume. In the tortuous mesh of highly branched and interconnected filaments, branches exhibited no preferred orientation except in the immediate vicinity of the cell membrane. We found that new filaments preferentially split off from the convex side of a bending filament, consistent with the behavior of Arp2/3-mediated branching of actin under mechanical deformation. Based on the quantitative analysis, the spine cytoskeleton is likely subject to considerable mechanical force in situ.
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| 2. |
- Meinicke, H., et al.
(författare)
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Tumour-associated changes in intestinal epithelial cells cause local accumulation of KLRG1(+) GATA3(+) regulatory T cells in mice
- 2017
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Ingår i: Immunology. - : Wiley. - 0019-2805. ; 152:1, s. 74-88
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Tidskriftsartikel (refereegranskat)abstract
- CD4(+) Foxp3(+) regulatory T (Treg) cells include differentiated populations of effector Treg cells characterized by the expression of specific transcription factors. Tumours, including intestinal malignancies, often present with local accumulation of Treg cells that can prevent tumour clearance, but how tumour progression leads to Treg cell accumulation is incompletely understood. Here using genetically modified mouse models we show that ablation of E-cadherin, a process associated with epithelial to mesenchymal transition and tumour progression, promotes the accumulation of intestinal Treg cells by the specific accumulation of the KLRG1(+) GATA3(+) Treg subset. Epithelial E-cadherin ablation activates the -catenin pathway, and we find that increasing -catenin signals in intestinal epithelial cells also boosts Treg cell frequencies through local accumulation of KLRG1(+) GATA3(+) Treg cells. Both E-cadherin ablation and increased -catenin signals resulted in epithelial cells with higher levels of interleukin-33, a cytokine that preferentially expands KLRG1(+) GATA3(+) Treg cells. Tumours often present reduced E-cadherin expression and increased -catenin signalling and interleukin-33 production. Accordingly, Treg cell accumulation in intestinal tumours from APC(min/+) mice was exclusively due to the increase in KLRG1(+) GATA3(+) Treg cells. Our data identify a novel axis through which epithelial cells control local Treg cell subsets, which may be activated during intestinal tumorigenesis.
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| 3. |
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| 4. |
- Yang, J, et al.
(författare)
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Guidelines and definitions for research on epithelial-mesenchymal transition
- 2020
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Ingår i: Nature reviews. Molecular cell biology. - : Springer Science and Business Media LLC. - 1471-0080 .- 1471-0072. ; 21:6, s. 341-352
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Tidskriftsartikel (refereegranskat)abstract
- Epithelial–mesenchymal transition (EMT) encompasses dynamic changes in cellular organization from epithelial to mesenchymal phenotypes, which leads to functional changes in cell migration and invasion. EMT occurs in a diverse range of physiological and pathological conditions and is driven by a conserved set of inducing signals, transcriptional regulators and downstream effectors. With over 5,700 publications indexed by Web of Science in 2019 alone, research on EMT is expanding rapidly. This growing interest warrants the need for a consensus among researchers when referring to and undertaking research on EMT. This Consensus Statement, mediated by ‘the EMT International Association’ (TEMTIA), is the outcome of a 2-year-long discussion among EMT researchers and aims to both clarify the nomenclature and provide definitions and guidelines for EMT research in future publications. We trust that these guidelines will help to reduce misunderstanding and misinterpretation of research data generated in various experimental models and to promote cross-disciplinary collaboration to identify and address key open questions in this research field. While recognizing the importance of maintaining diversity in experimental approaches and conceptual frameworks, we emphasize that lasting contributions of EMT research to increasing our understanding of developmental processes and combatting cancer and other diseases depend on the adoption of a unified terminology to describe EMT.
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| 5. |
- Mauritsen, Thorsten, et al.
(författare)
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Developments in the MPI-M Earth System Model version 1.2 (MPI-ESM1.2) and Its Response to Increasing CO2
- 2019
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Ingår i: Journal of Advances in Modeling Earth Systems. - 1942-2466. ; 11:4, s. 998-1038
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Tidskriftsartikel (refereegranskat)abstract
- A new release of the Max Planck Institute for Meteorology Earth System Model version 1.2 (MPI-ESM1.2) is presented. The development focused on correcting errors in and improving the physical processes representation, as well as improving the computational performance, versatility, and overall user friendliness. In addition to new radiation and aerosol parameterizations of the atmosphere, several relatively large, but partly compensating, coding errors in the model's cloud, convection, and turbulence parameterizations were corrected. The representation of land processes was refined by introducing a multilayer soil hydrology scheme, extending the land biogeochemistry to include the nitrogen cycle, replacing the soil and litter decomposition model and improving the representation of wildfires. The ocean biogeochemistry now represents cyanobacteria prognostically in order to capture the response of nitrogen fixation to changing climate conditions and further includes improved detritus settling and numerous other refinements. As something new, in addition to limiting drift and minimizing certain biases, the instrumental record warming was explicitly taken into account during the tuning process. To this end, a very high climate sensitivity of around 7 K caused by low-level clouds in the tropics as found in an intermediate model version was addressed, as it was not deemed possible to match observed warming otherwise. As a result, the model has a climate sensitivity to a doubling of CO2 over preindustrial conditions of 2.77 K, maintaining the previously identified highly nonlinear global mean response to increasing CO2 forcing, which nonetheless can be represented by a simple two-layer model.
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