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Article: Addressing Glutathione Redox Status in Clinical Samples by Two-Step Alkylation with N-ethylmaleimide Isotopologues.

Tomin, Tamara / Schittmayer, Matthias / Birner-Gruenberger, Ruth

2020 Volume 10, Issue 2

Abstract: Determination of the ratio of reduced to oxidized glutathione is of profound clinical interest in assessing the oxidative status of tissues and body fluids. However, this ratio is not yet a routine clinical parameter due to the analytically challenging ... ...

Abstract	Determination of the ratio of reduced to oxidized glutathione is of profound clinical interest in assessing the oxidative status of tissues and body fluids. However, this ratio is not yet a routine clinical parameter due to the analytically challenging interconversion of reduced (free) glutathione to oxidized (bound) glutathione. We aimed to facilitate this ratio determination in order to aid its incorporation as a routine clinical parameter. To this end, we developed a simple derivatization route that yields different isotopologues of N-ethylmaleimide alkylated glutathione from reduced and oxidized glutathione (after its chemical reduction) for mass spectrometric analysis. A third isotopologue can be used as isotopic standard for simultaneous absolute quantification. As all isotopologues have similar chromatographic properties, matrix effects arising from different sample origins can only impact method sensitivity but not quantification accuracy. Robustness, simplified data analysis, cost effectiveness by one common standard, and highly improved mass spectrometric sensitivity by conversion of oxidized glutathione to an alkylated glutathione isotopologue are the main advantages of our approach. We present a method fully optimized for blood, plasma, serum, cell, and tissue samples. In addition, we propose production of N-ethylmaleimide customized blood collection tubes to even further facilitate the analysis in a clinical setting.
Language	English
Publishing date	2020-02-16
Publishing country	Switzerland
Document type	Journal Article
ZDB-ID	2662251-8
ISSN	2218-1989
ISSN	2218-1989
DOI	10.3390/metabo10020071
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Article ; Online: Resolution Ladder for High-Resolution Mass Spectrometry.

Schittmayer, Matthias / Birner-Gruenberger, Ruth

Analytical chemistry

2017 Volume 89, Issue 18, Page(s) 9611–9615

Abstract: High-resolution mass spectrometry has become a key technology in life sciences. Since it is often unfeasible to find pairs of analytes with an appropriate mass difference to actually quantify the resolution experimentally, resolution is usually ... ...

Abstract	High-resolution mass spectrometry has become a key technology in life sciences. Since it is often unfeasible to find pairs of analytes with an appropriate mass difference to actually quantify the resolution experimentally, resolution is usually calculated from the shape of a single mass peak. In this study we show that the commonly employed strategy yields a poor measure of true resolution since it does not account for interactions that take place between ions of very similar mass and might be further distorted by signal processing effects. We present a straightforward and easily adaptable method to create a ladder of mass pairs to experimentally quantify actual mass resolution over a wide m/z range, compare the experimental resolution to the single peak based calculated resolution, and demonstrate the applicability of mass resolution ladders to study interactions of similar ions in various types of widely used mass spectrometers.
Language	English
Publishing date	2017-09-01
Publishing country	United States
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	1508-8
ISSN	1520-6882 ; 0003-2700
ISSN (online)	1520-6882
ISSN	0003-2700
DOI	10.1021/acs.analchem.7b02042
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Article: Resolution Ladder for High-Resolution Mass Spectrometry

Schittmayer, Matthias / Birner-Gruenberger Ruth

Analytical chemistry. 2017 Sept. 19, v. 89, no. 18

2017

Abstract	High-resolution mass spectrometry has become a key technology in life sciences. Since it is often unfeasible to find pairs of analytes with an appropriate mass difference to actually quantify the resolution experimentally, resolution is usually calculated from the shape of a single mass peak. In this study we show that the commonly employed strategy yields a poor measure of true resolution since it does not account for interactions that take place between ions of very similar mass and might be further distorted by signal processing effects. We present a straightforward and easily adaptable method to create a ladder of mass pairs to experimentally quantify actual mass resolution over a wide m/z range, compare the experimental resolution to the single peak based calculated resolution, and demonstrate the applicability of mass resolution ladders to study interactions of similar ions in various types of widely used mass spectrometers.
Keywords	ions ; ladders ; mass spectrometry ; spectrometers
Language	English
Dates of publication	2017-0919
Size	p. 9611-9615.
Publishing place	American Chemical Society
Document type	Article
ZDB-ID	1508-8
ISSN	1520-6882 ; 0003-2700
ISSN (online)	1520-6882
ISSN	0003-2700
DOI	10.1021%2Facs.analchem.7b02042
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Article ; Online: Human Sterols Are Overproduced, Stored and Excreted in Yeasts.

Radkohl, Astrid / Schusterbauer, Veronika / Bernauer, Lukas / Rechberger, Gerald N / Wolinski, Heimo / Schittmayer, Matthias / Birner-Gruenberger, Ruth / Thallinger, Gerhard G / Leitner, Erich / Baeck, Melanie / Pichler, Harald / Emmerstorfer-Augustin, Anita

International journal of molecular sciences

2024 Volume 25, Issue 2

Abstract: Sterols exert a profound influence on numerous cellular processes, playing a crucial role in both health and disease. However, comprehending the effects of sterol dysfunction on cellular physiology is challenging. Consequently, numerous processes ... ...

Abstract	Sterols exert a profound influence on numerous cellular processes, playing a crucial role in both health and disease. However, comprehending the effects of sterol dysfunction on cellular physiology is challenging. Consequently, numerous processes affected by impaired sterol biosynthesis still elude our complete understanding. In this study, we made use of yeast strains that produce cholesterol instead of ergosterol and investigated the cellular response mechanisms on the transcriptome as well as the lipid level. The exchange of ergosterol for cholesterol caused the downregulation of phosphatidylethanolamine and phosphatidylserine and upregulation of phosphatidylinositol and phosphatidylcholine biosynthesis. Additionally, a shift towards polyunsaturated fatty acids was observed. While the sphingolipid levels dropped, the total amounts of sterols and triacylglycerol increased, which resulted in 1.7-fold enlarged lipid droplets in cholesterol-producing yeast cells. In addition to internal storage, cholesterol and its precursors were excreted into the culture supernatant, most likely by the action of ABC transporters Snq2, Pdr12 and Pdr15. Overall, our results demonstrate that, similarly to mammalian cells, the production of non-native sterols and sterol precursors causes lipotoxicity in
MeSH term(s)	Animals ; Humans ; Sterols ; Saccharomyces cerevisiae ; Phytosterols ; Ergosterol ; Cholesterol ; Mammals
Chemical Substances	Sterols ; Phytosterols ; Ergosterol (Z30RAY509F) ; Cholesterol (97C5T2UQ7J)
Language	English
Publishing date	2024-01-08
Publishing country	Switzerland
Document type	Journal Article
ZDB-ID	2019364-6
ISSN	1422-0067 ; 1422-0067 ; 1661-6596
ISSN (online)	1422-0067
ISSN	1422-0067 ; 1661-6596
DOI	10.3390/ijms25020781
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Article ; Online: Comparative proteomics of common allergenic tree pollens of birch, alder, and hazel.

Darnhofer, Barbara / Tomin, Tamara / Liesinger, Laura / Schittmayer, Matthias / Tomazic, Peter Valentin / Birner-Gruenberger, Ruth

Allergy

2021 Volume 76, Issue 6, Page(s) 1743–1753

Abstract: Background: In addition to known allergens, other proteins in pollen can aid the development of an immune response in allergic individuals. The contribution of the "unknown" protein allergens is apparent in phylogenetically related species where, ... ...

Abstract	Background: In addition to known allergens, other proteins in pollen can aid the development of an immune response in allergic individuals. The contribution of the "unknown" protein allergens is apparent in phylogenetically related species where, despite of high homology of the lead allergens, the degree of allergenic potential can vary greatly. The aim of this study was to identify other potentially allergenic proteins in pollen of three common and highly related allergenic tree species: birch (Betula pendula), hazel (Corylus avellana) and alder (Alnus glutinosa). Methods: For that purpose, we carried out a comprehensive, comparative proteomic screening of the pollen from the three species. In order to maximize protein recovery and coverage, different protein extraction and isolation strategies during sample preparation were employed. Results: As a result, we report 2500-3000 identified proteins per each of the pollen species. Identified proteins were further used for a number of annotation steps, providing insight into differential distribution of peptidases, peptidase inhibitors and other potential allergenic proteins across the three species. Moreover, we carried out functional enrichment analyses that, interestingly, corroborated high species similarity in spite of their relatively distinct protein profiles. Conclusion: We provide to our knowledge first insight into proteomes of two very important allergenic pollen types, hazel and alder, where not even transcriptomics data are available, and compared them to birch. Datasets from this study can be readily used as protein databases and as such serve as basis for further functional studies.
MeSH term(s)	Allergens ; Alnus ; Betula ; Corylus ; Humans ; Pollen ; Proteomics ; Trees
Chemical Substances	Allergens
Language	English
Publishing date	2021-01-15
Publishing country	Denmark
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	391933-x
ISSN	1398-9995 ; 0105-4538
ISSN (online)	1398-9995
ISSN	0105-4538
DOI	10.1111/all.14694
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Article: Quantification of Cellular Folate Species by LC-MS after Stabilization by Derivatization

Schittmayer, Matthias / Birner-Gruenberger, Ruth / Zamboni, Nicola

Analytical chemistry. 2018 May 24, v. 90, no. 12

2018

Abstract: Folate cofactors play a key role in one-carbon metabolism. Analysis of individual folate species is hampered by the low chemical stability and high interconvertibility of folates, which can lead to severe experimental bias. Here, we present a complete ... ...

Abstract	Folate cofactors play a key role in one-carbon metabolism. Analysis of individual folate species is hampered by the low chemical stability and high interconvertibility of folates, which can lead to severe experimental bias. Here, we present a complete workflow that employs simultaneous extraction and stabilization of folates by derivatization. We perform reductive methylation employing stable isotope labeled reagents to retain information on the position and redox state of one-carbon units as well as the redox state of the pteridine ring. The derivatives are analyzed by a targeted LC(HILIC)-MS/MS method without the need for deconjugation, thereby also preserving the glutamation state of folates. The presented method does not only improve analyte coverage and sensitivity as compared to other published methods, it also greatly simplifies sample handling and storage. Finally, we report differences in the response of bacterial and mammalian systems to pharmacological inhibition of dihydrofolate reductase.
Keywords	derivatization ; dihydrofolate reductase ; folic acid ; hydrophilic interaction chromatography ; isotope labeling ; mammals ; mass spectrometry ; metabolism ; methylation ; stable isotopes
Language	English
Dates of publication	2018-0524
Size	p. 7349-7356.
Publishing place	American Chemical Society
Document type	Article
ZDB-ID	1508-8
ISSN	1520-6882 ; 0003-2700
ISSN (online)	1520-6882
ISSN	0003-2700
DOI	10.1021/acs.analchem.8b00650
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Article ; Online: Quantification of Cellular Folate Species by LC-MS after Stabilization by Derivatization.

Schittmayer, Matthias / Birner-Gruenberger, Ruth / Zamboni, Nicola

Analytical chemistry

2018 Volume 90, Issue 12, Page(s) 7349–7356

Abstract	Folate cofactors play a key role in one-carbon metabolism. Analysis of individual folate species is hampered by the low chemical stability and high interconvertibility of folates, which can lead to severe experimental bias. Here, we present a complete workflow that employs simultaneous extraction and stabilization of folates by derivatization. We perform reductive methylation employing stable isotope labeled reagents to retain information on the position and redox state of one-carbon units as well as the redox state of the pteridine ring. The derivatives are analyzed by a targeted LC(HILIC)-MS/MS method without the need for deconjugation, thereby also preserving the glutamation state of folates. The presented method does not only improve analyte coverage and sensitivity as compared to other published methods, it also greatly simplifies sample handling and storage. Finally, we report differences in the response of bacterial and mammalian systems to pharmacological inhibition of dihydrofolate reductase.
MeSH term(s)	Animals ; Bacterial Proteins ; Carbon ; Chromatography, Liquid/methods ; Folic Acid/analysis ; Folic Acid Antagonists ; Hep G2 Cells ; Humans ; Isotope Labeling ; Mammals ; Methods ; Methylation ; Oxidation-Reduction ; Pteroylpolyglutamic Acids/analysis ; Tandem Mass Spectrometry/methods ; Tetrahydrofolate Dehydrogenase/drug effects ; Workflow
Chemical Substances	Bacterial Proteins ; Folic Acid Antagonists ; Pteroylpolyglutamic Acids ; Carbon (7440-44-0) ; Folic Acid (935E97BOY8) ; Tetrahydrofolate Dehydrogenase (EC 1.5.1.3)
Language	English
Publishing date	2018-06-05
Publishing country	United States
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	1508-8
ISSN	1520-6882 ; 0003-2700
ISSN (online)	1520-6882
ISSN	0003-2700
DOI	10.1021/acs.analchem.8b00650
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Article: Blood Plasma Quality Control by Plasma Glutathione Status

Tomin, Tamara / Bordag, Natalie / Zügner, Elmar / Al-Baghdadi, Abdullah / Schinagl, Maximilian / Birner-Gruenberger, Ruth / Schittmayer, Matthias

Antioxidants. 2021 May 27, v. 10, no. 6

2021

Abstract: Timely centrifugation of blood for plasma preparation is a key step to ensure high plasma quality for analytics. Delays during preparation can significantly influence readouts of key clinical parameters. However, in a routine clinical environment, a ... ...

Abstract	Timely centrifugation of blood for plasma preparation is a key step to ensure high plasma quality for analytics. Delays during preparation can significantly influence readouts of key clinical parameters. However, in a routine clinical environment, a strictly controlled timeline is often not feasible. The next best approach is to control for sample preparation delays by a marker that provides a readout of the time-dependent degradation of the sample. In this study, we explored the usefulness of glutathione status as potential marker of plasma preparation delay. As the concentration of glutathione in erythrocytes is at least two orders of magnitude higher than in plasma, even the slightest leakage of glutathione from the cells can be readily observed. Over the 3 h observation period employed in this study, we observed a linear increase of plasma concentrations of both reduced (GSH) and oxidized glutathione (GSSG). Artificial oxidation of GSH is prevented by rapid alkylation with N-ethylmaleimide directly in the blood sampling vessel as recently published. The observed relative leakage of GSH was significantly higher than that of GSSG. A direct comparison with plasma lactate dehydrogenase activity, a widely employed hemolysis marker, clearly demonstrated the superiority of our approach for quality control. Moreover, we show that the addition of the thiol alkylating reagent NEM directly to the blood tubes does not influence downstream analysis of other clinical parameters. In conclusion, we report that GSH gives an excellent readout of the duration of plasma preparation and the associated pre-analytical errors.
Keywords	alkylation ; blood plasma ; centrifugation ; erythrocytes ; glutathione ; hemolysis ; lactate dehydrogenase ; oxidation ; quality control ; thiols
Language	English
Dates of publication	2021-0527
Publishing place	Multidisciplinary Digital Publishing Institute
Document type	Article
ZDB-ID	2704216-9
ISSN	2076-3921
ISSN	2076-3921
DOI	10.3390/antiox10060864
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Article ; Online: Hepatocyte Proteome Alterations Induced by Individual and Combinations of Common Free Fatty Acids.

Gindlhuber, Juergen / Schinagl, Maximilian / Liesinger, Laura / Darnhofer, Barbara / Tomin, Tamara / Schittmayer, Matthias / Birner-Gruenberger, Ruth

International journal of molecular sciences

2022 Volume 23, Issue 6

Abstract: Non-alcoholic fatty liver disease is a pathology with a hard-to-detect onset and is estimated to be present in a quarter of the adult human population. To improve our understanding of the development of non-alcoholic fatty liver disease, we treated a ... ...

Abstract	Non-alcoholic fatty liver disease is a pathology with a hard-to-detect onset and is estimated to be present in a quarter of the adult human population. To improve our understanding of the development of non-alcoholic fatty liver disease, we treated a human hepatoma cell line model, HepG2, with increasing concentrations of common fatty acids, namely myristic, palmitic and oleic acid. To reproduce more physiologically representative conditions, we also included combinations of these fatty acids and monitored the cellular response with an in-depth proteomics approach and imaging techniques. The two saturated fatty acids initially presented a similar phenotype of a dose-dependent decrease in growth rates and impaired lipid droplet formation. Detailed analysis revealed that the drop in the growth rates was due to delayed cell-cycle progression following myristic acid treatment, whereas palmitic acid led to cellular apoptosis. In contrast, oleic acid, as well as saturated fatty acid mixtures with oleic acid, led to a dose-dependent increase in lipid droplet volume without adverse impacts on cell growth. Comparing the effects of harmful single-fatty-acid treatments and the well-tolerated fatty acid mixes on the cellular proteome, we were able to differentiate between fatty-acid-specific cellular responses and likely common lipotoxic denominators.
MeSH term(s)	Fatty Acids/metabolism ; Fatty Acids, Nonesterified/metabolism ; Fatty Acids, Nonesterified/pharmacology ; Hepatocytes/metabolism ; Humans ; Non-alcoholic Fatty Liver Disease/metabolism ; Oleic Acid/metabolism ; Oleic Acid/pharmacology ; Palmitic Acid/metabolism ; Palmitic Acid/pharmacology ; Proteome/metabolism
Chemical Substances	Fatty Acids ; Fatty Acids, Nonesterified ; Proteome ; Oleic Acid (2UMI9U37CP) ; Palmitic Acid (2V16EO95H1)
Language	English
Publishing date	2022-03-20
Publishing country	Switzerland
Document type	Journal Article
ZDB-ID	2019364-6
ISSN	1422-0067 ; 1422-0067 ; 1661-6596
ISSN (online)	1422-0067
ISSN	1422-0067 ; 1661-6596
DOI	10.3390/ijms23063356
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Article ; Online: Proteomic Changes of Activated Hepatic Stellate Cells.

Schinagl, Maximilian / Tomin, Tamara / Gindlhuber, Juergen / Honeder, Sophie / Pfleger, Raphael / Schittmayer, Matthias / Trauner, Michael / Birner-Gruenberger, Ruth

International journal of molecular sciences

2021 Volume 22, Issue 23

Abstract: Hepatic stellate cells (HSC) are the major cellular drivers of liver fibrosis. Upon liver inflammation caused by a broad range of insults including non-alcoholic fatty liver, HSC transform from a quiescent into a proliferating, fibrotic phenotype. ... ...

Abstract	Hepatic stellate cells (HSC) are the major cellular drivers of liver fibrosis. Upon liver inflammation caused by a broad range of insults including non-alcoholic fatty liver, HSC transform from a quiescent into a proliferating, fibrotic phenotype. Although much is known about the pathophysiology of this process, exact cellular processes which occur in HSC and enable this transformation remain yet to be elucidated. In order to investigate this HSC transformation, we employed a simple, yet reliable model of HSC activation via an increase in growth medium serum concentration (serum activation). For that purpose, immortalized human LX-2 HSC were exposed to either 1% or 10% fetal bovine serum (FBS). Resulting quiescent (1% FBS) and activated (10% FBS) LX-2 cells were then subjected to in-depth mass spectrometry-based proteomics analysis as well as comprehensive phenotyping. Protein network analysis of activated LX-2 cells revealed an increase in the production of ribosomal proteins and proteins related to cell cycle control and migration, resulting in higher proliferation and faster migration phenotypes. Interestingly, we also observed a decrease in the expression of cholesterol and fatty acid biosynthesis proteins in accordance with a concomitant loss of cytosolic lipid droplets during activation. Overall, this work provides an update on HSC activation characteristics using contemporary proteomic and bioinformatic analyses and presents an accessible model for HSC activation. Data are available via ProteomeXchange with identifier PXD029121.
MeSH term(s)	Animals ; Cattle ; Cell Movement ; Cell Proliferation ; Hepatic Stellate Cells/drug effects ; Hepatic Stellate Cells/metabolism ; Humans ; Proteome/analysis ; Proteome/drug effects ; Proteome/metabolism ; Serum Albumin, Bovine/pharmacology
Chemical Substances	Proteome ; Serum Albumin, Bovine (27432CM55Q)
Language	English
Publishing date	2021-11-26
Publishing country	Switzerland
Document type	Journal Article
ZDB-ID	2019364-6
ISSN	1422-0067 ; 1422-0067 ; 1661-6596
ISSN (online)	1422-0067
ISSN	1422-0067 ; 1661-6596
DOI	10.3390/ijms222312782
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