| 1. |
- Gezelius, Henrik, 1977-, et al.
(författare)
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Conditional genetic labeling of the Renshaw cell population for functional studies of motor control
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The Renshaw cells were among the first interneurons to be characterized in the mammalian spinal cord. Although the basic function of recurrent inhibition to motor neurons, as well as the Renshaw cell connectivity to other neurons have been thoroughly studied, the exact functional role of the Renshaw cells in motor control is still unknown. To further characterize the role of Renshaw cells in spinal cord circuitry, we searched for candidate genes useful in the Cre-loxP system. It has been reported that the mRNA expression of nicotinic cholinergic receptor alpha 2 (Chrna2) is found in a restricted number of cells at the ventral rim in adult rat and mouse spinal cord. In our own search for genes with distinct ventral expression, we noted a similar restricted Chrna2 mRNA expression pattern in the mouse spinal cord at postnatal day (P) 11 and during development at embryonic day 14.5. Based on the fact that the gene product is a cholinergic receptor and the pattern of expression, the neurons are predicted to be Renshaw cells. The possibility that these cells were motor neurons was excluded, since Chrna2 and Vesicular acetylcholine were not co-expressed at P11. To further study this cell population, we have generated a transgenic mouse expressing Cre recombinase (Cre) under the control of the Chrna2 promoter region. To visualize the Cre-expressing cells, the Chrna2-Cre transgenic mouse were bred with a reporter mouse expressing β-galactosidase (β-gal) in the nucleus after loxP excision. As expected, spinal cord β-gal immunoreactivity was observed in a limited number of ventrally located cells in the Cre-bearing offspring. Co-labeling of β-gal with calbindin-28K, a known marker for Renshaw cells, indicated that a majority of the calbindin positive cells were also β-gal positive at the ventral rim where calbindin is specific. In addition, β-gal positive cells without observable calbindin were also detected. It is conceivable that Chrna2 is expressed in additional cells apart from Renshaw cells or that a previously unidentified Renshaw cell subpopulation does not express calbindin. Nonetheless, a mouse with Cre-activity restricted to Chrna2-expressing cells opens the possibility to functionally study a limited population of spinal cord interneurons through genetic techniques, with the ambition to explore the specific role of Renshaw cells in spinal cord circuitry and motor control.
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| 2. |
- Kirschenbaum, Daniel, et al.
(författare)
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Whole-brain microscopy reveals distinct temporal and spatial efficacy of anti-A beta therapies
- 2023
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Ingår i: EMBO Molecular Medicine. - : WILEY. - 1757-4676 .- 1757-4684. ; 15
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Tidskriftsartikel (refereegranskat)abstract
- Many efforts targeting amyloid-beta (A beta) plaques for the treatment of Alzheimers Disease thus far have resulted in failures during clinical trials. Regional and temporal heterogeneity of efficacy and dependence on plaque maturity may have contributed to these disappointing outcomes. In this study, we mapped the regional and temporal specificity of various anti-A beta treatments through high-resolution light-sheet imaging of electrophoretically cleared brains. We assessed the effect on amyloid plaque formation and growth in Thy1-APP/PS1 mice subjected to beta-secretase inhibitors, polythiophenes, or anti-A beta antibodies. Each treatment showed unique spatiotemporal A beta clearance, with polythiophenes emerging as a potent anti-A beta compound. Furthermore, aligning with a spatial-transcriptomic atlas revealed transcripts that correlate with the efficacy of each A beta therapy. As observed in this study, there is a striking dependence of specific treatments on the location and maturity of A beta plaques. This may also contribute to the clinical trial failures of A beta-therapies, suggesting that combinatorial regimens may be significantly more effective in clearing amyloid deposition.
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| 3. |
- Langer, Dominik, et al.
(författare)
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HelioScan : A software framework for controlling in vivo microscopy setups with high hardware flexibility, functional diversity and extendibility
- 2013
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Ingår i: Journal of Neuroscience Methods. - : Elsevier BV. - 0165-0270 .- 1872-678X. ; 215:1, s. 38-52
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Tidskriftsartikel (refereegranskat)abstract
- Intravital microscopy such as in vivo imaging of brain dynamics is often performed with custom-built microscope setups controlled by custom-written software to meet specific requirements. Continuous technological advancement in the field has created a need for new control software that is flexible enough to support the biological researcher with innovative imaging techniques and provide the developer with a solid platform for quickly and easily implementing new extensions. Here, we introduce HelioScan, a software package written in LabVIEW, as a platform serving this dual role. HelioScan is designed as a collection of components that can be flexibly assembled into microscope control software tailored to the particular hardware and functionality requirements. Moreover, HelioScan provides a software framework, within which new functionality can be implemented in a quick and structured manner. A specific HelioScan application assembles at run-time from individual software components, based on user-definable configuration files. Due to its component-based architecture, HelioScan can exploit synergies of multiple developers working in parallel on different components in a community effort. We exemplify the capabilities and versatility of HelioScan by demonstrating several in vivo brain imaging modes, including camera-based intrinsic optical signal imaging for functional mapping of cortical areas, standard two-photon laser-scanning microscopy using galvanometric mirrors, and high-speed in vivo two-photon calcium imaging using either acousto-optic deflectors or a resonant scanner. We recommend HelioScan as a convenient software framework for the in vivo imaging community.
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| 4. |
- Ni, Ruiqing, et al.
(författare)
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Multiscale optical and optoacoustic imaging of amyloid-beta deposits in mice
- 2022
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Ingår i: Nature Biomedical Engineering. - : NATURE PORTFOLIO. - 2157-846X. ; 6, s. 1031-1044
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Tidskriftsartikel (refereegranskat)abstract
- Large-field multifocal illumination fluorescence microscopy and panoramic volumetric multispectral optoacoustic tomography can be combined to longitudinally assess amyloid-beta deposits in transgenic mouse models of Alzheimers disease. Deposits of amyloid-beta (A beta) in the brains of rodents can be analysed by invasive intravital microscopy on a submillimetre scale, or via whole-brain images from modalities lacking the resolution or molecular specificity to accurately characterize A beta pathologies. Here we show that large-field multifocal illumination fluorescence microscopy and panoramic volumetric multispectral optoacoustic tomography can be combined to longitudinally assess A beta deposits in transgenic mouse models of Alzheimers disease. We used fluorescent A beta-targeted probes (the luminescent conjugated oligothiophene HS-169 and the oxazine-derivative AOI987) to transcranially detect A beta deposits in the cortex of APP/PS1 and arcA beta mice with single-plaque resolution (8 mu m) and across the whole brain (including the hippocampus and the thalamus, which are inaccessible by conventional intravital microscopy) at sub-150 mu m resolutions. Two-photon microscopy, light-sheet microscopy and immunohistochemistry of brain-tissue sections confirmed the specificity and regional distributions of the deposits. High-resolution multiscale optical and optoacoustic imaging of A beta deposits across the entire brain in rodents thus facilitates the in vivo study of A beta accumulation by brain region and by animal age and strain.
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| 5. |
- Renz, Aline F., et al.
(författare)
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Opto-E-Dura: A Soft, Stretchable ECoG Array for Multimodal, Multiscale Neuroscience
- 2020
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Ingår i: Advanced Healthcare Materials. - : WILEY. - 2192-2640 .- 2192-2659. ; 9:17
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Tidskriftsartikel (refereegranskat)abstract
- Soft, stretchable materials hold great promise for the fabrication of biomedical devices due to their capacity to integrate gracefully with and conform to biological tissues. Conformal devices are of particular interest in the development of brain interfaces where rigid structures can lead to tissue damage and loss of signal quality over the lifetime of the implant. Interfaces to study brain function and dysfunction increasingly require multimodal access in order to facilitate measurement of diverse physiological signals that span the disparate temporal and spatial scales of brain dynamics. Here the Opto-e-Dura, a soft, stretchable, 16-channel electrocorticography array that is optically transparent is presented. Its compatibility with diverse optical and electrical readouts is demonstrated enabling multimodal studies that bridge spatial and temporal scales. The device is chronically stable for weeks, compatible with wide-field and 2-photon calcium imaging and permits the repeated insertion of penetrating multielectrode arrays. As the variety of sensors and effectors realizable on soft, stretchable substrates expands, similar devices that provide large-scale, multimodal access to the brain will continue to improve fundamental understanding of brain function.
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| 6. |
- Zarb, Yvette, et al.
(författare)
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Ossified blood vessels in primary familial brain calcification elicit a neurotoxic astrocyte response
- 2019
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Ingår i: Brain. - : OXFORD UNIV PRESS. - 0006-8950 .- 1460-2156. ; 142:4, s. 885-902
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Tidskriftsartikel (refereegranskat)abstract
- Brain calcifications are commonly detected in aged individuals and accompany numerous brain diseases, but their functional importance is not understood. In cases of primary familial brain calcification, an autosomally inherited neuropsychiatric disorder, the presence of bilateral brain calcifications in the absence of secondary causes of brain calcification is a diagnostic criterion. To date, mutations in five genes including solute carrier 20 member 2 (SLC20A2), xenotropic and polytropic retrovirus receptor 1 (XPR1), myogenesis regulating glycosidase (MYORG), platelet-derived growth factor B (PDGFB) and platelet-derived growth factor receptor beta (PDGFRB), are considered causal. Previously, we have reported that mutations in PDGFB in humans are associated with primary familial brain calcification, and mice hypomorphic for PDGFB (Pdgfb(ret/ret)) present with brain vessel calcifications in the deep regions of the brain that increase with age, mimicking the pathology observed in human mutation carriers. In this study, we characterize the cellular environment surrounding calcifications in Pdgfb(ret/ret) animals and show that cells around vessel-associated calcifications express markers for osteoblasts, osteoclasts and osteocytes, and that bone matrix proteins are present in vessel-associated calcifications. Additionally, we also demonstrate the osteogenic environment around brain calcifications in genetically confirmed primary familial brain calcification cases. We show that calcifications cause oxidative stress in astrocytes and evoke expression of neurotoxic astrocyte markers. Similar to previously reported human primary familial brain calcification cases, we describe high interindividual variation in calcification load in Pdgfb(ret/ret) animals, as assessed by ex vivo and in vivo quantification of calcifications. We also report that serum of Pdgfb(ret/ret) animals does not differ in calcification propensity from control animals and that vessel calcification occurs only in the brains of Pdgfb(ret/ret) animals. Notably, ossification of vessels and astrocytic neurotoxic response is associated with specific behavioural and cognitive alterations, some of which are associated with primary familial brain calcification in a subset of patients.
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