scholarly journals Imaging Sterols and Oxysterols in Mouse Brain Reveals Distinct Spatial Cholesterol Metabolism

2018 ◽  
Author(s):  
Eylan Yutuc ◽  
Roberto Angelini ◽  
Mark Baumert ◽  
Natalia Mast ◽  
Irina Pikuleva ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Mouse Brain ◽  
Brain Function ◽  
Mass Spectrometry Imaging ◽  
Cholesterol Metabolism ◽  
Biologically Active ◽  
Wild Type ◽  
Tissue Slices ◽  
The Brain

AbstractDysregulated cholesterol metabolism is implicated in a number of neurological disorders. Many sterols, including cholesterol and its precursors and metabolites, are biologically active and important for proper brain function. However, spatial cholesterol metabolism in brain and the resulting sterol distributions are poorly defined. To better understand cholesterol metabolism in situ across the complex functional regions of brain, we have developed on-tissue enzyme-assisted derivatisation in combination with micro-liquid-extraction for surface analysis and liquid chromatography - mass spectrometry to image sterols in tissue slices (10 µm) of mouse brain. The method provides sterolomic analysis at 400 µm spot diameter with a limit of quantification of 0.01 ng/mm2. It overcomes the limitations of previous mass spectrometry imaging techniques in analysis of low abundance and difficult to ionise sterol molecules, allowing isomer differentiation and structure identification. Here we demonstrate the spatial distribution and quantification of multiple sterols involved in cholesterol metabolic pathways in wild type and cholesterol 24S-hydroxylase knock-out mouse brain. The technology described provides a powerful tool for future studies of spatial cholesterol metabolism in healthy and diseased tissues.SignificanceThe brain is a remarkably complex organ and cholesterol homeostasis underpins brain function. It is known that cholesterol is not evenly distributed across different brain regions, however, the precise map of cholesterol metabolism in the brain remains unclear. If cholesterol metabolism is to be correlated with brain function it is essential to generate such a map. Here we describe an advanced mass spectrometry imaging platform to reveal spatial cholesterol metabolism in situ at 400 µm resolution on 10 µm tissue slices from mouse brain. We mapped, not only cholesterol, but also other biologically active sterols arising from cholesterol turnover in both wild type and mice lacking cholesterol 24-hydroxylase (Cyp46a1), the major cholesterol metabolising enzyme.

scholarly journals Localization of sterols and oxysterols in mouse brain reveals distinct spatial cholesterol metabolism

2020 ◽  
Vol 117 (11) ◽  
pp. 5749-5760 ◽  
Author(s):  
Eylan Yutuc ◽  
Roberto Angelini ◽  
Mark Baumert ◽  
Natalia Mast ◽  
Irina Pikuleva ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Mouse Brain ◽  
Cholesterol Metabolism ◽  
Imaging Techniques ◽  
Biologically Active ◽  
Structure Identification ◽  
Tissue Slices ◽  
Limit Of Quantification ◽  
Functional Regions

Dysregulated cholesterol metabolism is implicated in a number of neurological disorders. Many sterols, including cholesterol and its precursors and metabolites, are biologically active and important for proper brain function. However, spatial cholesterol metabolism in brain and the resulting sterol distributions are poorly defined. To better understand cholesterol metabolism in situ across the complex functional regions of brain, we have developed on-tissue enzyme-assisted derivatization in combination with microliquid extraction for surface analysis and liquid chromatography-mass spectrometry to locate sterols in tissue slices (10 µm) of mouse brain. The method provides sterolomic analysis at 400-µm spot diameter with a limit of quantification of 0.01 ng/mm2. It overcomes the limitations of previous mass spectrometry imaging techniques in analysis of low-abundance and difficult-to-ionize sterol molecules, allowing isomer differentiation and structure identification. Here we demonstrate the spatial distribution and quantification of multiple sterols involved in cholesterol metabolic pathways in wild-type andcholesterol 24S-hydroxylaseknockout mouse brain. The technology described provides a powerful tool for future studies of spatial cholesterol metabolism in healthy and diseased tissues.

scholarly journals In situ characterisation of phytohormones from wounded Arabidopsis leaves using desorption electrospray ionisation mass spectrometry imaging

The Analyst ◽  
2021 ◽  
Author(s):  
Chao Zhang ◽  
Asta Žukauskaitė ◽  
Ivan Petřík ◽  
Aleš Pěnčík ◽  
Martin Hönig ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Plant Development ◽  
Plant Hormones ◽  
Stress Responses ◽  
Mass Spectrometry Imaging ◽  
Signalling Molecules ◽  
Ionisation Mass Spectrometry ◽  
Endogenous Regulators ◽  
Ionisation Mass

Phytohormones (plant hormones) are a group of small signalling molecules that act as important endogenous regulators in the plant development and stress responses. Previous research has identified phytohormone species, jasmonates,...

scholarly journals Transcriptomic, peptidomic and mass spectrometry imaging analysis of the brain in the ant Cataglyphis nodus

2021 ◽  
Author(s):  
Jens Habenstein ◽  
Franziska Schmitt ◽  
Sander Liessem ◽  
Alice Ly ◽  
Dennis Trede ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Mass Spectrometry Imaging ◽  
Imaging Analysis ◽  
The Brain

scholarly journals The microRNA miR-18a Links Proliferation and Inflammation During Photoreceptor Regeneration in the Injured Zebrafish Retina

2021 ◽  
Author(s):  
Evin Magner ◽  
Pamela Sandoval-Sanchez ◽  
Peter F Hitchcock ◽  
Scott M Taylor
Keyword(s):  
Muller Glia ◽  
Müller Glia ◽  
Wild Type ◽  
Post Injury ◽  
Photoreceptor Layer ◽  
Brdu Labeling ◽  
Key Aspects ◽  
The Brain ◽  
Embryonic Retina

Abstract In mammals, photoreceptor loss causes permanent blindness, but in zebrafish (Danio rerio), Müller glia function as intrinsic stem cells, producing progenitor cells that regenerate photoreceptors and restore vision. MicroRNAs (miRNAs) critically regulate neurogenesis in the brain and retina, but the roles of miRNAs in injury-induced neuronal regeneration are largely unknown. The miRNA miR-18a regulates photoreceptor differentiation in the embryonic retina. The purpose of the current study was to determine the function of miR-18a during injury-induced photoreceptor regeneration. RT-qPCR, in-situ hybridization (ISH) and immunohistochemistry (IHC) showed that miR-18a expression increases throughout the retina by 1-day post-injury (dpi) and continues to increase through 5 dpi. Bromodeoxyuridine (BrdU) labeling showed that at 7 and 10 dpi, when regenerated photoreceptors are normally differentiating, there are more proliferating Müller glia-derived progenitors in homozygous miR-18a mutant (miR-18ami5012) retinas compared with wild type (WT), indicating that miR-18a negatively regulates injury-induced proliferation. At 7 and 10 dpi, miR-18ami5012 retinas have fewer mature photoreceptors than WT, but there is no difference at 14 dpi, revealing that photoreceptor regeneration is delayed. BrdU labeling showed that the excess progenitors in miR-18ami5012 retinas migrate to other retinal layers besides the photoreceptor layer. Inflammation is critical for photoreceptor regeneration and RT-qPCR showed that, in the absence of miR-18a, inflammation is prolonged. Suppressing inflammation with dexamethasone rescues the miR-18ami5012 phenotype. Together, these data show that during injury-induced photoreceptor regeneration, miR-18a regulates proliferation and photoreceptor regeneration by regulating key aspects of the inflammatory response during photoreceptor regeneration in zebrafish.

scholarly journals Bispecific T-Cell Engager -Armored Chimeric Antigen Receptor T Cells Overcome Antigen Escape From EGFRvIII-Targeted Therapy For Glioblastoma

Neurosurgery ◽  
2019 ◽  
Vol 66 (Supplement_1) ◽  
Author(s):  
Bryan D Choi ◽  
Xiaoling Yu ◽  
Ana P Castano ◽  
Amanda A Bouffard ◽  
Andrea Schmidts ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Human Skin ◽  
Immune Therapy ◽  
Biologically Active ◽  
Target Antigen ◽  
Wild Type ◽  
Car T Cells ◽  
Car T ◽  
The Brain

Abstract INTRODUCTION Immune therapy with T cells engineered to express chimeric antigen receptors (CARs) represents a promising therapy for patients with glioblastoma (GBM). However, clinical responses have been limited due to heterogeneous target antigen expression and outgrowth of tumors lacking the antigen targeted by CAR T cells directed against a single target. In clinical studies with CART-EGFRvIII, EGFRvIII-targeted T cells successfully localized to the brain tumor microenvironment, but ultimately failed to prevent disease progression with post-treatment specimens demonstrating high levels of wild-type EGFR despite reduced expression of EGFRvIII. METHODS We developed a novel bicistronic CAR construct engineered for local delivery of bispecific T-cell engagers (BiTEs) that target residual tumor. Specifically, EGFRvIII-targeted CAR T cells were engineered to secrete BiTEs against wild-type EGFR, which is frequently amplified and overexpressed in GBM. RESULTS Human T cells were efficiently transduced with the dual CART.BiTE transgene. These modified cells secreted biologically active EGFR-specific BiTEs that not only redirected CAR T cells but also recruited and activated untransduced bystander T cells against wild-type EGFR. Recapitulating clinical data, EGFRvIII CAR T cells were unable to completely treat tumors with heterogenous EGFRvIII expression, leading to outgrowth of EGFRvIII-negative, EGFR-positive GBM. Conversely, CART.BiTE cells cured mice even in the setting of antigen-loss, against heterogeneous and well-established intracerebral tumors in mice. Unlike CAR T cells directly targeting EGFR, which caused toxicity in human skin grafts in vivo, secreted BiTE-EGFR was both locally effective and did not result in toxicity against grafted human skin. CONCLUSION This is the first instance in which CARs and BiTEs have been combined into a single platform of immune therapy. Our results demonstrate that CARs and BiTEs can be combined strategically to mitigate antigen heterogeneity in GBM and also provide a unique T-cell-based delivery method for BiTEs to tumors in the brain.

Inside front cover: In situ detection of histone variants and modifications in mouse brain using imaging mass spectrometry

PROTEOMICS ◽  
2016 ◽  
Vol 16 (3) ◽  
pp. NA-NA
Author(s):  
Shibojyoti Lahiri ◽  
Na Sun ◽  
Victor Solis-Mezarino ◽  
Andreas Fedisch ◽  
Jovica Ninkovic ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Mouse Brain ◽  
Imaging Mass Spectrometry ◽  
Histone Variants ◽  
Front Cover ◽  
In Situ Detection
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