Current neuroimaging techniques have very limited abilities to directly identify and quantify neurotransmitters from brain sections. We have developed a molecular-specific approach for the ...simultaneous imaging and quantitation of multiple neurotransmitters, precursors, and metabolites, such as tyrosine, tryptamine, tyramine, phenethylamine, dopamine, 3-methoxytyramine, serotonin, GABA, glutamate, acetylcholine, and L-alpha-glycerylphosphorylcholine, in histological tissue sections at high spatial resolutions. The method is employed to directly measure changes in the absolute and relative levels of neurotransmitters in specific brain structures in animal disease models and in response to drug treatments, demonstrating the power of mass spectrometry imaging in neuroscience.
•Molecular-specific neurotransmitter imaging in brain tissue sections•Quantitative imaging of neurotransmitters, metabolites, and precursors•Neurotransmitter imaging of experimental Parkinson’s disease models•Drug-induced changes in neurotransmitter levels in specific brain structures
Shariatgorji et al. have developed a unique molecular-specific approach to quantify concentration changes of neurotransmitters directly and simultaneously in brain tissue sections in disease models and in response to drug treatments, demonstrating the power of mass spectrometry imaging in neuroscience.
Mass spectrometry imaging in drug development Nilsson, Anna; Goodwin, Richard J A; Shariatgorji, Mohammadreza ...
Analytical chemistry (Washington),
02/2015, Letnik:
87, Številka:
3
Journal Article
Mass spectrometry imaging (MSI) enables the direct analysis of molecules from the surface of a wide variety of samples, allowing the multiplex measurement of both abundance and distribution of small ...molecules, lipids, peptides and proteins. As the technology has been refined an increasing number of ionization methods and mass analyzers has been used that enable increased spatial and spectral resolution measurements to be made at an increased speed. Alongside the instrumentation improvements there has been optimization of sample preparation procedures that allow the highest quality data to be obtained, reproducibly, from an ever increasing diversity of samples. This review will consider the development and standardization of sample preparation methods applicable to MSI, describing the stages and procedures undertaken from the instance of sample collection, through storage, preparation and on through final processing prior to analysis. Recent technical advancements will be highlighted and areas where further experimentation and optimization may well be required will be described. All aspects of the sample preparation pipeline will be considered in detail, with examples from the literature used to emphasize why rigorous sample preparation for MSI is vital to achieve the most accurate, reproducible and validated MSI data possible.
This article is part of a Special Issue entitled: Imaging Mass Spectrometry: A User’s Guide to a New Technique for Biological and Biomedical Research.
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► Sample preparation for MS imaging is reviewed in detail across four broad categories. ► Sample collection is reviewed and covers sacrifice, stabilization and storage. ► Sample processing is reviewed and covers dissection, sample mounting and sectioning. ► Sample post-processing is reviewed and covers clean-up, modification and quantification. ► Sample ionization-aiding processing is reviewed and covers matrix selection and application.
Metastasis constitutes the primary cause of cancer-related deaths, with the lung being a commonly affected organ. We found that activation of lung-resident group 2 innate lymphoid cells (ILC2s) ...orchestrated suppression of natural killer (NK) cell-mediated innate antitumor immunity, leading to increased lung metastases and mortality. Using multiple models of lung metastasis, we show that interleukin (IL)-33-dependent ILC2 activation in the lung is involved centrally in promoting tumor burden. ILC2-driven innate type 2 inflammation is accompanied by profound local suppression of interferon-γ production and cytotoxic function of lung NK cells. ILC2-dependent suppression of NK cells is elaborated via an innate regulatory mechanism, which is reliant on IL-5-induced lung eosinophilia, ultimately limiting the metabolic fitness of NK cells. Therapeutic targeting of IL-33 or IL-5 reversed NK cell suppression and alleviated cancer burden. Thus, we reveal an important function of IL-33 and ILC2s in promoting tumor metastasis via their capacity to suppress innate type 1 immunity.
Molecule-specific techniques such as MALDI and desorption electrospray ionization mass spectrometry imaging enable direct and simultaneous mapping of biomolecules in tissue sections in a single ...experiment. However, neurotransmitter imaging in the complex environment of biological samples remains challenging. Our covalent charge-tagging approach using on-tissue chemical derivatization of primary and secondary amines and phenolic hydroxyls enables comprehensive mapping of neurotransmitter networks. Here, we present robust and easy-to-use chemical derivatization protocols that facilitate quantitative and simultaneous molecular imaging of complete neurotransmitter systems and drugs in diverse biological tissue sections with high lateral resolution. This is currently not possible with any other imaging technique. The protocol, using fluoromethylpyridinium and pyrylium reagents, describes all steps from tissue preparation (~1 h), chemical derivatization (1-2 h), data collection (timing depends on the number of samples and lateral resolution) and data analysis and interpretation. The specificity of the chemical reaction can also help users identify unknown chemical identities. Our protocol can reveal the cellular locations in which signaling molecules act and thus shed light on the complex responses that occur after the administration of drugs or during the course of a disease.
We have previously demonstrated liquid extraction surface analysis (LESA) high field asymmetric waveform ion mobility spectrometry (FAIMS) mass spectrometry imaging of proteins in thin tissue ...sections of brain and liver. Here, we present an improved approach that makes use of multiple static FAIMS parameters at each sampled location and allows a significant improvement in the number of proteins, lipids, and drugs that can be imaged simultaneously. The approach is applied to the mass spectrometry imaging of control and cassette-dosed rat kidneys. Mass spectrometry imaging of kidneys typically requires washing to remove excess hemoglobin; however, that is not necessary with this approach. Multistep static FAIMS mass spectrometry resulted in a 6- to 16-fold increase in the number of proteins detected in the absence of FAIMS, in addition to smaller increases over single step static FAIMS (chosen for optimum transmission of total protein ions). The benefits of multistep static FAIMS mass spectrometry for protein detection are also shown for sections of testes. The numbers of proteins detected following multistep FAIMS increased between 2- and 3-fold over single step FAIMS and between 2- and 14-fold over LESA alone. Finally, to date, LESA mass spectrometry of proteins in tissue has been undertaken solely on fresh frozen samples. In this work, we demonstrate that heat-preserved tissues are also suitable for these analyses. Heat preservation of tissue improved the number of proteins detected by LESA MS for both kidney and testes tissue (by between 2- and 4-fold). For both tissue types, the majority of the proteins additionally detected in the heat-treated samples were subsequently detected in the frozen samples when FAIMS was incorporated. Improvements in the numbers of proteins detected were observed for LESA FAIMS MS for the kidney tissue; for testes tissue, fewer total proteins were detected following heat preservation; however, approximately one-third were unique to the heat-preserved samples.
Clinical tissue specimens are often unscreened, and preparation of tissue sections for analysis by mass spectrometry imaging (MSI) can cause aerosolization of particles potentially carrying an ...infectious load. We here present a decontamination approach based on ultraviolet-C (UV-C) light to inactivate clinically relevant pathogens such as herpesviridae, papovaviridae human immunodeficiency virus, or SARS-CoV-2, which may be present in human tissue samples while preserving the biodistributions of analytes within the tissue. High doses of UV-C required for high-level disinfection were found to cause oxidation and photodegradation of endogenous species. Lower UV-C doses maintaining inactivation of clinically relevant pathogens to a level of increased operator safety were found to be less destructive to the tissue metabolome and xenobiotics. These doses caused less alterations of the tissue metabolome and allowed elucidation of the biodistribution of the endogenous metabolites. Additionally, we were able to determine the spatially integrated abundances of the ATR inhibitor ceralasertib from decontaminated human biopsies using desorption electrospray ionization-MSI (DESI-MSI).
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