Desorption Electrospray Ionization Imaging Mass Research Articles

Spatial Distribution, Antioxidant Capacity, and Spore Germination-Promoting Effect of Bibenzyls from Marchantia polymorpha.

Liverworts, considered to be the first plant type to successfully make the transition from water to land, can resist different oxidative stress. As characteristic constituents of liverworts, the bibenzyls are efficient antioxidants. In this study, spatial distributions of the bibenzyls within Marchantia polymorpha L., the model species of liverworts, were mapped using airflow-assisted desorption electrospray ionization imaging mass spectrometry. Bibenzyls were found to largely exist in the female receptacle of M. polymorpha, where lunularic acid was found to focus in the central region and bisbibenzyls were enriched in the periphery. The region-specific gene expression and antioxidant activities were characterized. In line with the spatial feature of bibenzyls, higher MpSTCS1A and Mp4CL expression levels and antioxidant ability were exhibited in the archegoniophore. The expression level of MpSTCS1A, and the content of total phenolic acid was increased after UV-B irradiation, suggesting bibenzyls play an important role in UV-B tolerance. Moreover, lunularic acid and extract of archegoniophore at a certain concentration can stimulate the spore germination under normal conditions and UV-B stress. These works broaden our understanding of the significance of bibenzyls in spore propagation and environmental adaptation.

Spatial Distribution and Stability of Cholinesterase Inhibitory Protoberberine Alkaloids from Papaver setiferum.

During a research program to identify new cholinesterase inhibitors of natural origin, two new 7,8-didehydroprotoberberine alkaloids (1 and 2) and nine known compounds (3–11) were isolated from the capsules of the common ornamental poppy, Papaver setiferum (previously P. pseudo-orientale). Despite their reported instability, the 7,8-didehydroprotoberberines isolated herein appeared relatively stable, particularly as their trifluoroacetic acid salts. The spatial distributions of the isolated alkaloids were also analyzed using desorption electrospray ionization imaging mass spectrometry. The alkaloids were localized predominantly within the walls and vascular bundles of the capsules, with the highest relative abundances occurring in the lower half of the capsules toward the peduncle. The relative abundances of the alkaloids were also compared across plant development stages. Although most alkaloids did not show clear patterns in their concentration across development stages, the concentration of suspected oxidation products clearly spiked upon plant death. Finally, all isolated natural products were screened for inhibitory activities against a panel of cholinesterases, from both human and animal sources. These studies identified several competitive inhibitors of cholinesterases with potency in the low micromolar range (1–4, 6, 7), offering new lead compounds for the development of cholinesterase inhibitory drugs.

The stability of the metabolic turnover of arachidonic acid in human unruptured intracranial aneurysmal walls is sustained

ObjectiveIntracranial aneurysm (IA) is considered a chronic inflammatory condition that affects intracranial arteries. Cyclooxygenase 2 (COX2) and prostaglandin E2 (PGE2) are considered potential targets of specific medical treatment for IAs. Previous studies have reported the elevated COX2 expression in the IA wall. However, not much has been studied about the upstream regulation of COX2 and PGE2, and the metabolism of arachidonic acid (AA) in human IAs. In this study, we aimed to elucidate the distribution of fatty acids in human IA walls for the first time. MethodsSamples from 6 ruptured and 5 unruptured human IAs were surgically resected after the aneurysmal clipping and analyzed using desorption electrospray ionization imaging mass spectrometry. ResultsAA and AA-containing phospholipids were not detected in the unruptured IA walls. On the contrast, significantly larger amounts of AA and AA-containing phospholipids were detected in the ruptured IA walls compared to unruptured IA walls. ConclusionsThis study showed for the first time that AA was not detected in unruptured human IA walls. Our findings suggest that the stability of the turnover of AA in human unruptured IA walls is sustained. In contrast, this study showed that larger amounts of AA and AA-containing phospholipids were detected in the ruptured IA walls. More cases and further analysis are necessary to interpret our present results.

Dietary Intake of Green Nut Oil or DHA Ameliorates DHA Distribution in the Brain of a Mouse Model of Dementia Accompanied by Memory Recovery.

Docosahexaenoic acid (DHA), an omega-3 polyunsaturated fatty acid, has significant health benefits. Previous studies reported decreased levels of DHA and DHA-containing phosphatidylcholines in the brain of animals suffering from Alzheimer’s disease, the most common type of dementia; furthermore, DHA supplementation has been found to improve brain DHA levels and memory efficiency in dementia. Oil extracted from the seeds of Plukenetia volubilis (green nut oil; GNO) is also expected to have DHA like effects as it contains approximately 50% α-linolenic acid, a precursor of DHA. Despite this, changes in the spatial distribution of DHA in the brain of animals with dementia following GNO or DHA supplementation remain unexplored. In this study, desorption electrospray ionization imaging mass spectrometry (DESI-IMS) was applied to observe the effects of GNO or DHA supplementation upon the distribution of DHA in the brain of male senescence-accelerated mouse-prone 8 (SAMP8) mice, a mouse model of dementia. DESI-IMS revealed that brain DHA distribution increased 1.85-fold and 3.67-fold in GNO-fed and DHA-fed SAMP8 mice, respectively, compared to corn oil-fed SAMP8 mice. Memory efficiency in SAMP8 mice was also improved by GNO or DHA supplementation. In summary, this study suggests the possibility of GNO or DHA supplementation for the prevention of dementia.

Visualized analysis of within-tissue spatial distribution of specialized metabolites in tea (Camellia sinensis) using desorption electrospray ionization imaging mass spectrometry

Although specialized metabolite distributions in different tea (Camellia sinensis) tissues has been studied extensively, little is known about their within-tissue distribution owing to the lack of nondestructive methodology. In this study, desorption electrospray ionization imaging mass spectrometry was used to investigate the within-tissue spatial distributions of specialized metabolites in tea. To overcome the negative effects of the large amount of wax on tea leaves, several sample preparation methods were compared, with a Teflon-imprint method established for tea leaves. Polyphenols are characteristic metabolites in tea leaves. Epicatechin gallate/catechin gallate, epigallocatechin gallate/gallocatechin gallate, and gallic acid were evenly distributed on both sides of the leaves, while epicatechin/catechin, epigallocatechin/gallocatechin, and assamicain A were distributed near the leaf vein. L-Theanine was mainly accumulated in tea roots. L-Theanine and valinol were distributed around the outer root cross-section. The results will advance our understanding of the precise localizations and in-vivo biosyntheses of specialized metabolites in tea.

Discovery of lipid biomarkers correlated with disease progression in clear cell renal cell carcinoma using desorption electrospray ionization imaging mass spectrometry.

Clear cell renal cell carcinoma (ccRCC) often results in recurrence or metastasis, and there are only a few clinically effective biomarkers for early diagnosis and personalized therapy. Metabolic changes have been widely studied using mass spectrometry (MS) of tissue lysates to identify novel biomarkers. Our objective was to identify lipid biomarkers that can predict disease progression in ccRCC by a tissue-based approach. We retrospectively investigated lipid molecules in cancerous tissues and normal renal cortex tissues obtained from patients with ccRCC (n = 47) using desorption electrospray ionization imaging mass spectrometry (DESI-IMS). We selected eight candidate lipid biomarkers showing higher signal intensity in cancerous than in normal tissues, with a clear distinction of the tissue type based on the images. Of these candidates, low maximum intensity ratio (cancerous/normal) values of ions of oleic acid, m/z 389.2, and 391.3 significantly correlated with shorter progression-free survival compared with high maximum intensity ratio values (P = 0.011, P = 0.022, and P < 0.001, respectively). This study identified novel lipid molecules contributing to the prediction of disease progression in ccRCC using DESI-IMS. Our findings on lipid storage may provide a new diagnostic or therapeutic strategy for targeting cancer cell metabolism.

MP88-06 EXPLORATION OF BIOMARKERS ASSOCIATED WITH PROGNOSIS IN PATIENTS WITH CLEAR CELL RENAL CELL CARCINOMA UNDERGOING SURGICAL RESECTION BY DESORPTION ELECTROSPRAY IONIZATION IMAGING MASS SPECTROMETRY

You have accessJournal of UrologyKidney Cancer: Basic Research & Pathophysiology III1 Apr 2018MP88-06 EXPLORATION OF BIOMARKERS ASSOCIATED WITH PROGNOSIS IN PATIENTS WITH CLEAR CELL RENAL CELL CARCINOMA UNDERGOING SURGICAL RESECTION BY DESORPTION ELECTROSPRAY IONIZATION IMAGING MASS SPECTROMETRY Keita Tamura, Makoto Horikawa, Takayuki Sugiyama, Hideaki Miyake, and Mitsutoshi Setou Keita TamuraKeita Tamura More articles by this author , Makoto HorikawaMakoto Horikawa More articles by this author , Takayuki SugiyamaTakayuki Sugiyama More articles by this author , Hideaki MiyakeHideaki Miyake More articles by this author , and Mitsutoshi SetouMitsutoshi Setou More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2018.02.2926AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Proteome analysis has become one of the major approaches for the investigation of biomarkers predicting the prognosis of various types of malignant tumor, while metabolome analysis has recently been introduced in this field as the novel promising approach. Despite being widely spread for the screening of small biomolecules, conventional mass spectrometry (MS) analysis using tissue lysate cannot clearly distinguish between the cancerous and non-cancerous tissues; thus, there is a risk for obtaining false positive candidates. In this study, we applied desorption electrospray ionization imaging mass spectrometry (DESI-IMS), a novel molecular anatomy technique, to analyze a broad range of lipids in specimens from patients with clear cell renal cell carcinoma (CCRCC) to identify biomarkers that can predict the prognosis in these patients. METHODS Paired samples of the cancerous and normal renal cortex tissues were obtained from a total of 31 patients with CCRCC undergoing surgical resection. The DESI-IMS analyses of thinly sectioned samples were performed in negative ion mode with Xevo G2-XS (Waters, US). We picked up the ions showing 1.5 times higher signal intensity on the cancerous tissue compared with the normal tissue using High Definition Imaging software, and identified the molecules with LIPID MAPS database. We also analyzed the impact of candidate molecules on the overall survival (OS) in these 31 CCRCC patients. RESULTS The ions of m/z 187.10 (azelaic acid), m/z 279.23 (linoleic acid), m/z 281.25 (oleic acid), m/z 329.25 (docosapentaenoic acid), m/z 389.24 (not assigned), m/z 391.26 (not assigned), m/z 773.53 (PG (36:2)) were identified as the candidate biomarkers. Of these biomarkers, the low signal intensity of oleic acid as well as the high signal intensity of m/z 391.26 appeared to be significantly associated with the OS in the 31 patients with CCRCC. CONCLUSIONS In this study, we first identified seven lipid molecules specifically elevated on the cancerous tissue of CCRCC, and found the significant impacts of the signal intensities of oleic acid and m/z 391.26 on the prognosis of CCRCC patients undergoing surgical resection. Although future prospective study with a larger sample size will be required, these findings provide new insights for early diagnosis and prognostic prediction in patients with CCRCC. © 2018FiguresReferencesRelatedDetails Volume 199Issue 4SApril 2018Page: e1199 Advertisement Copyright & Permissions© 2018MetricsAuthor Information Keita Tamura More articles by this author Makoto Horikawa More articles by this author Takayuki Sugiyama More articles by this author Hideaki Miyake More articles by this author Mitsutoshi Setou More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Desorption Electrospray Ionization Imaging Mass Spectrometry as a Tool for Investigating Model Prebiotic Reactions on Mineral Surfaces.

Mineral-assisted thermal decomposition of formamide (HCONH(2)) is a heavily studied model prebiotic reaction that has offered valuable insights into the plausible pathways leading to the chemical building blocks of primordial informational polymers. To date, most efforts have focused on the analysis of formamide reaction products released in solution, although several studies have examined the role of mineral catalysts in promoting this chemistry. We show here that the direct investigation of reactive mineral surfaces by desorption electrospray ionization-mass spectrometry imaging (DESI-MSI) gives a new perspective on the important role of the mineral surface in the formation of reaction products. As a proof-of-principle example, we show that DESI-MSI allows interrogation of the molecular products produced on heterogeneous granite samples with minimal sample preparation. Purine and pyrimidine nucleobases and their derivatives are successfully detected by DESI-MSI, with a strong correlation of the spatial product distribution with the mineral microenvironment. To our knowledge, this study is the first application of DESI-MSI to the study of complex and porous mineral surfaces and their roles in chemical evolution. This DESI-MSI approach is generally applicable to a wide range of reactions or other processes involving minerals.

Analysis of colorectal adenocarcinoma tissue by desorption electrospray ionization mass spectrometric imaging

Negative ion desorption electrospray ionization (DESI) was used for the analysis of an ex vivo tissue sample set comprising primary colorectal adenocarcinoma samples and colorectal adenocarcinoma liver metastasis samples. Frozen sections (12 μm thick) were analyzed by means of DESI imaging mass spectrometry (IMS) with spatial resolution of 100 μm using a computer-controlled DESI imaging stage mounted on a high resolution Orbitrap mass spectrometer. DESI-IMS data were found to predominantly feature complex lipids, including phosphatidyl-inositols, phophatidyl-ethanolamines, phosphatidyl-serines, phosphatidyl-ethanolamine plasmalogens, phosphatidic acids, phosphatidyl-glycerols, ceramides, sphingolipids, and sulfatides among others. Molecular constituents were identified based on their exact mass and MS/MS fragmentation spectra. An identified set of molecules was found to be in good agreement with previously reported DESI imaging data. Different histological tissue types were found to yield characteristic mass spectrometric data in each individual section. Histological features were identified by comparison to hematoxylin-eosin stained neighboring sections. Ions specific to certain histological tissue types (connective tissue, smooth muscle, healthy mucosa, healthy liver parenchyma, and adenocarcinoma) were identified by semi-automated screening of data. While each section featured a number of tissue-specific species, no potential global biomarker was found in the full sample set for any of the tissue types. As an alternative approach, data were analyzed by principal component analysis (PCA) and linear discriminant analysis (LDA) which resulted in efficient separation of data points based on their histological types. A pixel-by-pixel tissue identification method was developed, featuring the PCA/LDA analysis of authentic data set, and localization of unknowns in the resulting 60D, histologically assigned LDA space. Novel approach was found to yield results which are in 95% agreement with the results of classical histology. KRAS mutation status was determined for each sample by standard molecular biology methods and a similar PCA/LDA approach was developed to assess the feasibility of the determination of this important parameter using solely DESI imaging data. Results showed that the mutant and wild-type samples fully separated. DESI-MS and molecular biology results were in agreement in 90% of the cases.

Visualization by mass spectrometry of 2‐dimensional changes in rat brain lipids, includingN‐acylphosphatidylethanolamines, during neonatal brain ischemia

Spatial synthesis of N-acyl-phosphatidylethanolamines (NAPEs) and N-acylethanolamines (NAEs) during ischemia-reperfusion in neonatal rats has been investigated and compared to the spatial degradation of other phospholipids. Ischemia was induced in anesthetized Wistar P7 rat pups by left middle cerebral artery electrocoagulation combined with a transient and concomitant occlusion of both common carotid arteries. Pups were sacrificed after 24 and 48 h. Sham-treated animals were sacrificed after 48 h. The frozen brains were sliced and subjected to desorption electrospray ionization imaging mass spectrometry. There was a remarkable increase in the levels of many species of NAPEs in the whole injured area at both time points, and a clear but minor increase in selected NAEs. In the ischemic area, the sodium adducts of phosphatidylcholine and of lyso-phosphatidylcholine accumulated and the potassium adduct of phosphatidylcholine disappeared, indicating breakdown of the Na(+)/K(+) pump. Free fatty acids, e.g., arachidonic and docosahexaenoic acids, tended to be more abundant in the periphery than in the center of the ischemic area and showed different spatial distribution. NAPEs are synthesized in the whole ischemic area where the cells seem to be dead and other phospholipids are degraded. Free fatty acids can be found in the periphery of the ischemic area.

Characterization of barley leaf tissue using direct and indirect desorption electrospray ionization imaging mass spectrometry

Chemical profiling of barley (Hordeum vulgare) leaves was demonstrated using direct and indirect desorption electrospray ionization (DESI) imaging mass spectrometry. Direct DESI analysis of the untreated leaves was not possible despite a significant content of hydroxynitrile glucosides known to reside in the epidermis of the leaves. Instead, the epidermis was stripped off the leaves, thus allowing direct DESI imaging to be performed on the back of the epidermis. Furthermore, indirect DESI imaging was performed by making imprints in porous Teflon of the intact leaves as well as of the stripped epidermis. The DESI images reveal accumulation of hydroxynitrile glucosides in the leaf epidermis, homogeneously distributed throughout the surface. The indirect DESI approach enables relative quantitation, confirming variations of hydroxynitrile glucosides content in primary leaves of three different cultivars of barley seedlings. The study presents an example of how to overcome the morphological barriers from the plant surface and perform rapid and repeatable DESI imaging. In addition, a comparison is made of direct and indirect DESI imaging, contributing to the characterization of the recently developed method of indirect DESI imaging of plant material via porous Teflon imprints.

Distinctive Glycerophospholipid Profiles of Human Seminoma and Adjacent Normal Tissues by Desorption Electrospray Ionization Imaging Mass Spectrometry

Desorption electrospray ionization mass spectrometry (DESI-MS) has been successfully used to discriminate between normal and cancerous human tissue from different anatomical sites. On the basis of this, DESI-MS imaging was used to characterize human seminoma and adjacent normal tissue. Seminoma and adjacent normal paired human tissue sections (40 tissues) from 15 patients undergoing radical orchiectomy were flash frozen in liquid nitrogen and sectioned to 15μm thickness and thaw mounted to glass slides. The entire sample was two-dimensionally analyzed by the charged solvent spray to form a molecular image of the biological tissue. DESI-MS images were compared with formalin-fixed, hematoxylin and eosin (H&E) stained slides of the same material. Increased signal intensity was detected for two seminolipids [seminolipid (16:0/16:0) and seminolipid (30:0)] in the normal tubule testis tissue; these compounds were undetectable in seminoma tissue, as well as from the surrounding fat, muscle, and blood vessels. A glycerophosphoinositol [PI(18:0/20:4)] was also found at increased intensity in the normal testes tubule tissue when compared with seminoma tissue. Ascorbic acid (i.e., vitamin C) was found at increased amounts in seminoma tissue when compared with normal tissue. DESI-MS analysis was successfully used to visualize the location of several types of molecules across human seminoma and normal tissues. Discrimination between seminoma and adjacent normal testes tubules was achieved on the basis of the spatial distributions and varying intensities of particular lipid species as well as ascorbic acid. The increased presence of ascorbic acid within seminoma compared with normal seminiferous tubules was previously unknown.

Analysis of Secondary Plant Metabolites by Indirect Desorption Electrospray Ionization Imaging Mass Spectrometry

Secondary metabolites in plant material can be imaged in a simple and robust way by creating an imprint of the plant material on a porous Teflon surface. The Teflon surface serves to extract compounds from the plant material for enhanced desorption electrospray ionization imaging analysis, while maintaining the spatial information of the sample. The method, which remedies for limitations in mass spectrometry imaging of compounds embedded in plant material, was demonstrated on leaves and petals of Hypericum perforatum and leaves of Datura stramonium.

Mapping Lipid Alterations in Traumatically Injured Rat Spinal Cord by Desorption Electrospray Ionization Imaging Mass Spectrometry

Desorption electrospray ionization (DESI) mass spectrometry (MS) is used in an imaging mode to interrogate the lipid profiles of 15 μm thin tissue cross sections of injured rat spinal cord and normal healthy tissue. Increased relative intensities of fatty acids, diacylglycerols, and lysolipids (between +120% and +240%) as well as a small decrease in intensities of lipids (-30%) were visualized in the lesion epicenter and adjacent areas after spinal cord injury. This indicates the hydrolysis of lipids during the demyelination process due to activation of phospholipase A(2) enzyme. In addition, signals corresponding to oxidative degradation products, such as prostaglandin and hydroxyeicosatetraenoic acid, exhibited increased signal intensity by a factor of 2 in the negative ion mode in lesions relative to the normal healthy tissue. Analysis of malondialdehyde, a product of lipid peroxidation and marker of oxidative stress, was accomplished in the ambient environment using reactive DESI mass spectrometry imaging. This was achieved by electrospraying reagent solution containing dinitrophenylhydrazine as high-velocity charged droplets onto the tissue section. The hydrazine reacts selectively and rapidly with the carbonyl groups of malondialdehyde, and signal intensity of twice the intensity was detected in the lesions compared to healthy spinal cord. With a small amount of tissue sample, DESI-MS imaging provides information on the composition and distribution of specific compounds (limited by the occurrence of isomeric lipids with very similar fragmentation patterns) in lesions after spinal cord injury in comparison with normal healthy tissue allowing identification of the extent of the lesion and its repair.

Discrimination of human astrocytoma subtypes by lipid analysis using desorption electrospray ionization imaging mass spectrometry.

Discrimination of human astrocytoma subtypes by lipid analysis using desorption electrospray ionization imaging mass spectrometry.

Discrimination of Human Astrocytoma Subtypes by Lipid Analysis Using Desorption Electrospray Ionization Imaging Mass Spectrometry

Die Differenzierung von astrozytischen Hirntumorgraden kann durch direkte Lipidanalyse mittels Desorptions-Elektrosprayionisations-Massenspektrometrie (DESI-MS) erreicht werden. Charakteristische Lipidprofile sind mit der Tumormalignanz entsprechend den WHO-Graden II, III und IV assoziiert (siehe Bild).

Desorption Electrospray Ionization Imaging Mass Spectrometry of Lipids in Rat Spinal Cord

Imaging mass spectrometry allows for the direct investigation of tissue samples to identify specific biological compounds and determine their spatial distributions. Desorption electrospray ionization (DESI) mass spectrometry has been used for the imaging and analysis of rat spinal cord cross sections. Glycerophospholipids and sphingolipids, as well as fatty acids, were detected in both the negative and positive ion modes and identified through tandem mass spectrometry (MS/MS) product ion scans using collision-induced dissociation and accurate mass measurements. Differences in the relative abundances of lipids and free fatty acids were present between white and gray matter areas in both the negative and positive ion modes. DESI-MS images of the corresponding ions allow the determination of their spatial distributions within a cross section of the rat spinal cord, by scanning the DESI probe across the entire sample surface. Glycerophospholipids and sphingolipids were mostly detected in the white matter, while the free fatty acids were present in the gray matter. These results show parallels with reported distributions of lipids in studies of rat brain. This suggests that the spatial intensity distribution reflects relative concentration differences of the lipid and fatty acid compounds in the spinal cord tissue. The "butterfly" shape of the gray matter in the spinal cord cross section was resolved in the corresponding ion images, indicating that a lateral resolution of better than 200 mum was achieved. The selected ion images of lipids are directly correlated with anatomic features on the spinal cord corresponding to the white and the gray matter.

Lipid profiles of canine invasive transitional cell carcinoma of the urinary bladder and adjacent normal tissue by desorption electrospray ionization imaging mass spectrometry.

Desorption electrospray ionization mass spectrometry (DESI-MS) was used in an imaging mode to interrogate the lipid profiles of thin tissue sections of canine spontaneous invasive transitional cell carcinoma of the urinary bladder (a model of human invasive bladder cancer) as well as adjacent normal tissue from four different dogs. The glycerophospholipids and sphingolipids that appear as intense signals in both the negative ion and positive ion modes were identified by tandem mass spectrometry product ion scans using collision-induced dissociation. Differences in the relative distributions of the lipid species were present between the tumor and adjacent normal tissue in both the negative and positive ion modes. DESI-MS images showing the spatial distributions of particular glycerophospholipids, sphinoglipids, and free fatty acids in both the negative and positive ion modes were compared to serial tissue sections that were stained with hematoxylin and eosin (H&E). Increased absolute and relative intensities for at least five different glycerophospholipids and three free fatty acids in the negative ion mode and at least four different lipid species in the positive ion mode were seen in the tumor region of the samples in all four dogs. In addition, one sphingolipid species exhibited increased signal intensity in the positive ion mode in normal tissue relative to the diseased tissue. Principal component analysis was also used to generate unsupervised statistical images from the negative ion mode data, and these images are in excellent agreement with the DESI images obtained from the selected ions and also the H&E-stained tissue.