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Sekera ER, Somogyi Á, Takáts Z, Stappert F, Thom C, Schmitz OJ, Moeckel C, Paizs B, Sommertune J. Utilization of bis-MPA Dendrimers for the Calibration of Ion Mobility Collision Cross Section Calculations. J Am Soc Mass Spectrom 2024. [PMID: 38739888 DOI: 10.1021/jasms.3c00428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Ion mobility-mass spectrometry (IM-MS) has become increasingly popular with the rapid expansion of available techniques and instrumentation. To enable accuracy, standardization, and repeatability of IM-MS measurements, the community requires reliable and well-defined reference materials for calibration and tuning of the equipment. To address this need, synthetic dendrimers of high chemical and structural purity were tested on three ion mobility platforms as potential calibrants. First, synthesized dendrimers were characterized by drift tube ion mobility (DTIMS), using an Agilent 6560 IM-qTOF-MS to assess their drift tube collision cross section (DTCCS) values. Then, assessment of obtained CCS values on trapped ion mobility (TIMS) and traveling wave ion mobility (TWIMS) ion mobility platforms were compared to those found by DTIMS. Across all three systems, dendrimers were found to have high potential for m/z and ion mobility calibration in the CCS range of 160-1700 Å2. To further validate their use as calibrants, drift tube calculated CCS values for dendrimers were utilized to calibrate calculations of CCS for known standards including Agilent Tuning mix, the CCS Major mix from Waters, and SPLASH LIPIDOMIX. Additionally, structures of sodiated dendrimers were computated along with theoretical CCS values which showed good agreement with the experimental CCS values. On the basis of the results presented, we recommend the use of dendrimers as alternatives and/or complementary compounds to commonly used calibrants for ion mobility platforms.
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Affiliation(s)
- Emily R Sekera
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - Árpád Somogyi
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - Zoltan Takáts
- Rosalind Franklin Institute, Harwell Campus, Didcot OX11 0QX, U.K
| | - Florian Stappert
- University of Duisburg-Essen, Applied Analytical Chemistry, 45141 Essen, Germany
| | - Cedric Thom
- University of Duisburg-Essen, Applied Analytical Chemistry, 45141 Essen, Germany
| | - Oliver J Schmitz
- University of Duisburg-Essen, Applied Analytical Chemistry, 45141 Essen, Germany
| | - Claudia Moeckel
- Stockholm University, Department of Materials and Environmental Chemistry, 10691 Stockholm, Sweden
| | - Béla Paizs
- Rosalind Franklin Institute, Harwell Campus, Didcot OX11 0QX, U.K
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Sekera ER, Rosas L, Holbrook JH, Angeles QD, Khaliullin T, Rojas M, Mora AL, Hummon AB. Single Cell MALDI-MS Imaging of Lipids and Proteins in Senescent Fibroblasts. bioRxiv 2024:2024.03.13.584140. [PMID: 38559151 PMCID: PMC10980017 DOI: 10.1101/2024.03.13.584140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
In this study, we evaluate the lipidomic and proteomic profiles of human lung fibroblasts (hLFs) to interrogate changes occurring due to senescence. To study single cell populations, a comparison of cell adhered onto slides utilizing poly-D-lysine versus centrifugal force deposition was first analyzed to determine whether specific alterations were observed between preparations. The poly-D-lysine approach was than utilized to interrogate the lipidome of the cell populations and further evaluate potential applications of the MALDI-IHC platform for single-cell level analyses. Altogether, our results show the ability to detect lipids implicated in senescence and alterations to protein expression between normal and senescent fibroblast populations. This report is the first time that the MALDI-IHC system has been utilized at a single-cell level for analyzing the expression of proteins.
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Sekera ER, Akkaya-Colak KB, Lopez A, Mihaylova MM, Hummon AB. Mass Spectrometry Imaging and Histology for the Analysis of Budding Intestinal Organoids. Anal Chem 2024; 96:4251-4258. [PMID: 38427328 PMCID: PMC10955551 DOI: 10.1021/acs.analchem.3c05725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2024]
Abstract
Three-dimensional (3D) organoids have been at the forefront of regenerative medicine and cancer biology fields for the past decade. However, the fragile nature of organoids makes their spatial analysis challenging due to their budding structures and composition of single layer of cells. The standard sample preparation approaches can collapse the organoid morphology. Therefore, in this study, we evaluated several approaches to optimize a method compatible with both mass spectrometry imaging (MSI) and immunohistological techniques. Murine intestinal organoids were used to evaluate embedding in gelatin, carboxymethylcellulose (CMC)-gelatin-CMC-sucrose, or hydroxypropyl methylcellulose (HPMC) and polyvinylpyrrolidone (PVP) solutions. Organoids were assessed with and without aldehyde fixation and analyzed for lipid distributions by MSI coupled with hematoxylin and eosin (H&E) staining and immunofluorescence (IF) in consecutive sections from the same sample. While chemical fixation preserves morphology for better histological outcomes, it can lead to suppression of the matrix-assisted laser desorption/ionization (MALDI) lipid signal. By contrast, leaving organoid samples unfixed enhanced MALDI lipid signal. The method that performed best for both MALDI and histological analysis was embedding unfixed samples in HPMC and PVP. This approach allowed assessment of cell proliferation by Ki67 while also identifying putative phosphatidylethanolamine (PE(18:0/18:1)), which was confirmed further by tandem MS approaches. Overall, these protocols will be amenable to multiplexing imaging mass spectrometry analysis with several histological assessments and help advance our understanding of the biological processes that take place in district subsets of cells in budding organoid structures.
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Affiliation(s)
- Emily R Sekera
- Department of Chemistry and Biochemistry, The Ohio State University, 100 W 18th Ave, Columbus, Ohio 43210, United States
| | - Kubra B Akkaya-Colak
- Department of Biological Chemistry and Pharmacology, The Ohio State University, 1060 Carmack Rd, Columbus, Ohio 43210, Columbus, Ohio 43210, United States
- Comprehensive Cancer Center, The Ohio State University, 410 W 12th Ave, Columbus, Ohio 43210, United States
| | - Arbil Lopez
- Department of Chemistry and Biochemistry, The Ohio State University, 100 W 18th Ave, Columbus, Ohio 43210, United States
| | - Maria M Mihaylova
- Department of Biological Chemistry and Pharmacology, The Ohio State University, 1060 Carmack Rd, Columbus, Ohio 43210, Columbus, Ohio 43210, United States
- Comprehensive Cancer Center, The Ohio State University, 410 W 12th Ave, Columbus, Ohio 43210, United States
| | - Amanda B Hummon
- Department of Chemistry and Biochemistry, The Ohio State University, 100 W 18th Ave, Columbus, Ohio 43210, United States
- Comprehensive Cancer Center, The Ohio State University, 410 W 12th Ave, Columbus, Ohio 43210, United States
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Chua AE, Pfeifer L, Sekera ER, Hummon AB, Desaire H. Workflow for Evaluating Normalization Tools for Omics Data Using Supervised and Unsupervised Machine Learning. J Am Soc Mass Spectrom 2023; 34:2775-2784. [PMID: 37897440 PMCID: PMC10919320 DOI: 10.1021/jasms.3c00295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/30/2023]
Abstract
To achieve high quality omics results, systematic variability in mass spectrometry (MS) data must be adequately addressed. Effective data normalization is essential for minimizing this variability. The abundance of approaches and the data-dependent nature of normalization have led some researchers to develop open-source academic software for choosing the best approach. While these tools are certainly beneficial to the community, none of them meet all of the needs of all users, particularly users who want to test new strategies that are not available in these products. Herein, we present a simple and straightforward workflow that facilitates the identification of optimal normalization strategies using straightforward evaluation metrics, employing both supervised and unsupervised machine learning. The workflow offers a "DIY" aspect, where the performance of any normalization strategy can be evaluated for any type of MS data. As a demonstration of its utility, we apply this workflow on two distinct datasets, an ESI-MS dataset of extracted lipids from latent fingerprints and a cancer spheroid dataset of metabolites ionized by MALDI-MSI, for which we identified the best-performing normalization strategies.
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Affiliation(s)
- Aleesa E. Chua
- Department of Chemistry, University of Kansas, Lawrence, Kansas, United States, 66045
| | - Leah Pfeifer
- Department of Chemistry, University of Kansas, Lawrence, Kansas, United States, 66045
| | - Emily R. Sekera
- Department of Chemistry and Biochemistry and the Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio 43210, United States
| | - Amanda B. Hummon
- Department of Chemistry and Biochemistry and the Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio 43210, United States
| | - Heather Desaire
- Department of Chemistry, University of Kansas, Lawrence, Kansas, United States, 66045
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Liyana Gunawardana VW, Ward C, Wang H, Holbrook JH, Sekera ER, Cui H, Hummon AB, Badjić JD. Crystalline Nanoparticles of Water-Soluble Covalent Basket Cages (CBCs) for Encapsulation of Anticancer Drugs. Angew Chem Int Ed Engl 2023; 62:e202306722. [PMID: 37332078 PMCID: PMC10528532 DOI: 10.1002/anie.202306722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 06/06/2023] [Accepted: 06/16/2023] [Indexed: 06/20/2023]
Abstract
We herein describe the preparation, assembly, recognition characteristics, and biocompatibility of novel covalent basket cage CBC-11, composed of four molecular baskets linked to four trivalent aromatic amines through amide groups. The cage is tetrahedral in shape and similar in size to small proteins (Mw =8637 g/mol) with a spacious nonpolar interior for accommodating multiple guests. While 24 carboxylates at the outer surface of CBC-11 render it soluble in aqueous phosphate buffer (PBS) at pH=7.0, the amphiphilic nature prompts its assembly into nanoparticles (d=250 nm, DLS). Cryo-TEM examination of nanoparticles revealed their crystalline nature with wafer-like shapes and hexagonally arranged cages. Nanoparticulate CBC-11 traps anticancer drugs irinotecan and doxorubicin, with each cage binding up to four drug molecules in a non-cooperative manner. The inclusion complexation resulted in nanoparticles growing in size and precipitating. In media containing mammalian cells (HCT 116, human colon carcinoma), the IC50 value of CBC-11 was above 100 μM. While this work presents the first example of a large covalent organic cage operating in water at the physiological pH and forming crystalline nanoparticles, it also demonstrates its biocompatibility and potential to act as a polyvalent binder of drugs for their sequestration or delivery.
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Affiliation(s)
| | - Carson Ward
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, OH 43210, USA
| | - Han Wang
- Department of Chemical and Biomolecular Engineering, The Johns Hopkins University, Maryland Hall 221, 3400 North Charles Street, Baltimore, MD, USA
| | - Joseph H Holbrook
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, OH 43210, USA
| | - Emily R Sekera
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, OH 43210, USA
| | - Honggang Cui
- Department of Chemical and Biomolecular Engineering, The Johns Hopkins University, Maryland Hall 221, 3400 North Charles Street, Baltimore, MD, USA
| | - Amanda B Hummon
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, OH 43210, USA
| | - Jovica D Badjić
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, OH 43210, USA
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Holbrook JH, Sekera ER, Lopez A, Fries BD, Tobias F, Akkaya K, Mihaylova MM, Hummon AB. Enhancement of Lipid Signals in Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry with Ammonium Fluoride as a Matrix Additive. Anal Chem 2023; 95:10603-10609. [PMID: 37418337 PMCID: PMC10655718 DOI: 10.1021/acs.analchem.3c00753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/09/2023]
Abstract
Lipids are essential macromolecules that play a crucial role in numerous biological events. Lipids are structurally diverse which allows them to fulfill multiple functional roles. Matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) is a powerful tool to understand the spatial localization of lipids within biological systems. Herein, we report the use of ammonium fluoride (NH4F) as a comatrix additive to enhance lipid detection in biological samples, with a signal increase of up to 200%. Emphasis was placed on anionic lipid enhancement with negative polarity measurements, with some preliminary work on cationic lipids detailed. We observed lipid signal enhancement of [M-H]- ions with the addition of NH4F additive attributed to a proton transfer reaction in several different lipid classes. Overall, our study demonstrates that the use of the NH4F comatrix additive substantially improves sensitivity for lipid detection in a MALDI system and is capable of being applied to a variety of different applications.
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Affiliation(s)
- Joseph H. Holbrook
- Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio 43210, United States
| | - Emily R. Sekera
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - Arbil Lopez
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - Brian D. Fries
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - Fernando Tobias
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - Kubra Akkaya
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, Ohio 43210, United States
| | - Maria M. Mihaylova
- Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio 43210, United States
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, Ohio 43210, United States
- Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio 43210, United States
| | - Amanda B. Hummon
- Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio 43210, United States
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
- Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio 43210, United States
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Hempfling JP, Sekera ER, Sarkar A, Hummon AB, Pei D. Generation of Proteins with Free N-Terminal Cysteine by Aminopeptidases. J Am Chem Soc 2022; 144:21763-21771. [PMID: 36378906 PMCID: PMC9923720 DOI: 10.1021/jacs.2c10194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Efficient, site-specific, and bio-orthogonal conjugation of chemical functionalities to proteins is of great utility in fundamental research as well as industrial processes (e.g., the production of antibody-drug conjugates and immobilization of enzymes for biocatalysis). A popular approach involves reacting a free N-terminal cysteine with a variety of electrophilic reagents. However, current methods for generating proteins with N-terminal cysteines have significant limitations. Herein we report a novel, efficient, and convenient method for producing recombinant proteins with free N-terminal cysteines by genetically fusing a Met-Pro-Cys sequence to the N-terminus of a protein of interest and subjecting the recombinant protein to the sequential action of methionine and proline aminopeptidases. The resulting protein was site-specifically labeled at the N-terminus with fluorescein and a cyclic cell-penetrating peptide through native chemical ligation and a 2-cyanobenzothiazole moiety, respectively. In addition, the optimal recognition sequence of Aeromonas sobria proline aminopeptidase was determined by screening a combinatorial peptide library and incorporated into the N-terminus of a protein of interest for most efficient N-terminal processing.
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Affiliation(s)
- Jordan P. Hempfling
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, United States
| | - Emily R. Sekera
- Department of Chemistry and Biochemistry, The Ohio State University, 484 West 12 Avenue, Columbus, OH 43210, United States
| | - Amar Sarkar
- Department of Chemistry and Biochemistry, The Ohio State University, 484 West 12 Avenue, Columbus, OH 43210, United States
| | - Amanda B. Hummon
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, United States
- Department of Chemistry and Biochemistry, The Ohio State University, 484 West 12 Avenue, Columbus, OH 43210, United States
- Comprehensive Cancer Center, The Ohio State University, Columbus, OH 43210, United States
| | - Dehua Pei
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, United States
- Department of Chemistry and Biochemistry, The Ohio State University, 484 West 12 Avenue, Columbus, OH 43210, United States
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Sekera ER, Saraswat D, Zemaitis KJ, Sim FJ, Wood TD. MALDI Mass Spectrometry Imaging in a Primary Demyelination Model of Murine Spinal Cord. J Am Soc Mass Spectrom 2020; 31:2462-2468. [PMID: 32926612 PMCID: PMC8628303 DOI: 10.1021/jasms.0c00187] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Destruction of myelin, or demyelination, is a characteristic of traumatic spinal cord injury and pathognomonic for primary demyelinating pathologies such as multiple sclerosis (MS). The regenerative process known as remyelination, which can occur following demyelination, fails as MS progresses. Models of focal demyelination by local injection of gliotoxins have provided important biological insights into the demyelination/remyelination process. Here, injection of lysolecithin to induce spinal cord demyelination is investigated using matrix-assisted laser desorption/ionization mass spectrometry imaging. A segmentation analysis revealed changes to the lipid composition during lysolecithin-induced demyelination at the lesion site and subsequent remyelination over time. The results of this study can be utilized to identify potential myelin-repair mechanisms and in the design of therapeutic strategies to enhance myelin repair.
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Affiliation(s)
- Emily R Sekera
- Department of Chemistry, Natural Sciences Complex, University at Buffalo State University of New York, Buffalo, New York 14260-3000, United States
| | - Darpan Saraswat
- Department of Pharmacology & Toxicology, Jacobs School of Medicine and Biomedical Sciences, 955 Main Street, University at Buffalo State University of New York, Buffalo, New York 14203, United States
| | - Kevin J Zemaitis
- Department of Chemistry, Natural Sciences Complex, University at Buffalo State University of New York, Buffalo, New York 14260-3000, United States
| | - Fraser J Sim
- Department of Pharmacology & Toxicology, Jacobs School of Medicine and Biomedical Sciences, 955 Main Street, University at Buffalo State University of New York, Buffalo, New York 14203, United States
| | - Troy D Wood
- Department of Chemistry, Natural Sciences Complex, University at Buffalo State University of New York, Buffalo, New York 14260-3000, United States
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Sekera ER, Wood TD. Sequencing Proteins from Bottom to Top: Combining Techniques for Full Sequence Analysis of Glucokinase. Advances in Experimental Medicine and Biology 2019; 1140:111-119. [DOI: 10.1007/978-3-030-15950-4_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Abstract
INTRODUCTION Autism spectrum disorders (ASD) are a group of neurodevelopmental disorders lacking a clinical biomarker for diagnosis. Emerging evidence shows that intestinal microflora from ASD subjects can be distinguished from controls, suggesting metabolite differences due to the action of intestinal microbes may provide a means for identifying potential biomarkers for ASD. OBJECTIVES The aim of this study was to determine if quantitative differences in levels of stercobilin and stercobilinogen, metabolites produced by biological action of intestinal microflora, exist in the fecal matter between an ASD mouse model population and controls. METHODS Pairs of fecal samples were collected from two mouse groups, an ASD model group with Timothy syndrome 2 (TS2-NEO) and a gender-matched control group. After centrifugation, supernatant was spiked with an 18O-labeled stercobilin isotopomer and subjected to solid phase extraction for processing. Extracted samples were spotted on a stainless steel plate and subjected to matrix-assisted laser desorption and ionization mass spectrometry using dihydroxybenzoic acid as the matrix (n = 5). Peak areas for bilins and 18O-stercobilin isotopomers were determined in each fecal sample. RESULTS A 40-45% depletion in stercobilin in TS2-NEO fecal samples compared with controls was observed with p < 0.05; a less dramatic depletion was observed for stercobilinogen. CONCLUSIONS The results show that stercobilin depletion in feces is observed for an ASD mouse model vs. controls. This may help to explain recent observations of a less diverse microbiome in humans with ASD and may prove helpful in developing a clinical ASD biomarker.
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Affiliation(s)
- Emily R. Sekera
- Department of Chemistry, Natural Sciences Complex, University at Buffalo, State University of New York, Buffalo, NY
| | - Heather L. Rudolph
- Department of Chemistry, Natural Sciences Complex, University at Buffalo, State University of New York, Buffalo, NY
| | - Stephen D. Carro
- Department of Chemistry, Natural Sciences Complex, University at Buffalo, State University of New York, Buffalo, NY
| | - Michael J. Morales
- Department of Physiology and Biophysics, University at Buffalo, State University of New York, Buffalo, NY
| | - Glenna C. L. Bett
- Department of Physiology and Biophysics, University at Buffalo, State University of New York, Buffalo, NY
- Department of Gynecology and Obstetrics, University at Buffalo, State University of New York, Buffalo, NY
| | - Randall L. Rasmusson
- Department of Physiology and Biophysics, University at Buffalo, State University of New York, Buffalo, NY
- Department of Biomedical Engineering, University at Buffalo, State University of New York, Buffalo, NY
| | - Troy D. Wood
- Department of Chemistry, Natural Sciences Complex, University at Buffalo, State University of New York, Buffalo, NY
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Gerloff J, Sundar IK, Freter R, Sekera ER, Friedman AE, Robinson R, Pagano T, Rahman I. Inflammatory Response and Barrier Dysfunction by Different e-Cigarette Flavoring Chemicals Identified by Gas Chromatography-Mass Spectrometry in e-Liquids and e-Vapors on Human Lung Epithelial Cells and Fibroblasts. ACTA ACUST UNITED AC 2017; 3:28-40. [PMID: 28337465 PMCID: PMC5338075 DOI: 10.1089/aivt.2016.0030] [Citation(s) in RCA: 148] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Recent studies suggest that electronic cigarette (e-cig) flavors can be harmful to lung tissue by imposing oxidative stress and inflammatory responses. The potential inflammatory response by lung epithelial cells and fibroblasts exposed to e-cig flavoring chemicals in addition to other risk-anticipated flavor enhancers inhaled by e-cig users is not known. The goal of this study was to evaluate the release of the proinflammatory cytokine (interleukin-8 [IL-8]) and epithelial barrier function in response to different e-cig flavoring chemicals identified in various e-cig e-liquid flavorings and vapors by chemical characterization using gas chromatography–mass spectrometry analysis. Flavorings, such as acetoin (butter), diacetyl, pentanedione, maltol (malt), ortho-vanillin (vanilla), coumarin, and cinnamaldehyde in comparison with tumor necrosis factor alpha (TNFα), were used in this study. Human bronchial epithelial cells (Beas2B), human mucoepidermoid carcinoma epithelial cells (H292), and human lung fibroblasts (HFL-1) were treated with each flavoring chemical for 24 hours. The cells and conditioned media were then collected and analyzed for toxicity (viability %), lung epithelial barrier function, and proinflammatory cytokine IL-8 release. Cell viability was not significantly affected by any of the flavoring chemicals tested at a concentration of 10 μM to 1 mM. Acetoin and diacetyl treatment induced IL-8 release in Beas2B cells. Acetoin- and pentanedione-treated HFL-1 cells produced a differential, but significant response for IL-8 release compared to controls and TNFα. Flavorings, such as ortho-vanillin and maltol, induced IL-8 release in Beas2B cells, but not in H292 cells. Of all the flavoring chemicals tested, acetoin and maltol were more potent inducers of IL-8 release than TNFα in Beas2B and HFL-1 cells. Flavoring chemicals rapidly impaired epithelial barrier function in human bronchial epithelial cells (16-HBE) as measured by electric cell surface impedance sensing. Our findings suggest that some of the e-cig liquids/aerosols containing flavoring chemicals can cause significant loss of epithelial barrier function and proinflammatory response in lung cells.
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Affiliation(s)
- Janice Gerloff
- Department of Environmental Medicine, University of Rochester Medical Center , Rochester, New York
| | - Isaac K Sundar
- Department of Environmental Medicine, University of Rochester Medical Center , Rochester, New York
| | - Robert Freter
- Department of Environmental Medicine, University of Rochester Medical Center , Rochester, New York
| | - Emily R Sekera
- Department of Chemistry, University of Buffalo , Buffalo, New York
| | - Alan E Friedman
- Department of Chemistry, University of Buffalo , Buffalo, New York
| | - Risa Robinson
- Department of Mechanical Engineering, Rochester Institute of Technology/National Technical Institute for the Deaf , Rochester, New York
| | - Todd Pagano
- Department of Science & Mathematics, Rochester Institute of Technology/National Technical Institute for the Deaf , Rochester, New York
| | - Irfan Rahman
- Department of Environmental Medicine, University of Rochester Medical Center , Rochester, New York
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Rudolph HL, Sekera ER, Wood TD. Stable (18) O-labeling method for stercobilin and other bilins for metabolomics. Rapid Commun Mass Spectrom 2016; 30:1469-1474. [PMID: 27321834 PMCID: PMC4916856 DOI: 10.1002/rcm.7580] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 03/30/2016] [Accepted: 04/03/2016] [Indexed: 06/06/2023]
Abstract
RATIONALE Bilin tetrapyrroles including stercobilin are unique to mammalian waste; they have been used as markers of source water contamination and may have important diagnostic value in human health conditions. Unfortunately, commercial isotopomers for bilins are not available. Thus, there is a need for isotopomer standards of stercobilin and other bilins for quantification in environmental and clinical diagnostic applications. METHODS A procedure is described here using H2 (18) O to label the carboxylic acid groups of bilin tetrapyrroles. Reaction conditions as a function of temperature and reagent volume were found to produce a mixture of isotopomers, as assessed by electrospray ionization and Fourier transform ion cyclotron resonance mass spectrometry (FTICRMS). Stability as a function of storage time and temperature and in conjunction with solid-phase extraction (SPE) was assessed. RESULTS The highest labeling efficiency was achieved at 70 °C for 8 h, while a stable ratio of the isotopmers could be produced at 60 °C for 4 h. The stability of the isotopic distribution was maintained under storage (room temperature or frozen) for 20 days. It was also stable throughout SPE. The high mass accuracy and resolving power of FTICRMS enables clear distinction between (18) O-labeled bilins from other unlabeled bilins present, avoiding a potential interference in quantitation. CONCLUSIONS A procedure was developed to label bilins with (18) O. The final ratio of the (18) O-labeled bilin isotopomers was reproducible and highly stable for at least 20 days under storage. This ratio was not changed in any statistically significant way even after SPE. Thus a reliable method for producing stable isotopomer ratios for bilins has been achieved. Copyright © 2016 John Wiley & Sons, Ltd.
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