Can supervise: YES
Clases, D, de Vega, RG, Funke, S, Lockwood, TE, Westerhausen, MT, Taudte, RV, Adlard, PA & Doble, PA 2020, 'Matching sensitivity to abundance: high resolution immuno-mass spectrometry imaging of lanthanide labels and endogenous elements in the murine brain', JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY, vol. 35, no. 4, pp. 728-735.View/Download from: Publisher's site
Rao, SS, Lago, L, Gonzalez de Vega, R, Bray, L, Hare, DJ, Clases, D, Doble, PA & Adlard, PA 2020, 'Characterising the spatial and temporal brain metal profile in a mouse model of tauopathy', METALLOMICS, vol. 12, no. 2, pp. 301-313.View/Download from: Publisher's site
Clases, D, Gonzalez De Vega, R, Adlard, PA & Doble, PA 2019, 'On-line reverse isotope dilution analysis for spatial quantification of elemental labels used in immunohistochemical assisted imaging mass spectrometry: Via LA-ICP-MS', Journal of Analytical Atomic Spectrometry, vol. 34, no. 2, pp. 407-412.View/Download from: Publisher's site
© 2019 The Royal Society of Chemistry. We present a novel on-line isotope dilution analysis (IDA) approach for the quantification of isotopically enriched metal labels used in immunohistochemical assisted imaging mass spectrometry. This technique advances recently reported on-line IDA for laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS) by performing on-line reverse IDA of isotopically enriched elements commonly used as labels for antibodies. This approach allows relative quantification of biomolecules and is superior to other methods that have long acquisition times such as three-dimensional LA-ICP-MS, or when higher sample throughput is required. As a proof of concept, anti-tyrosine hydroxylase was labelled with Yb isotopes and incubated on two parallel cryocut sections of a mouse brain. IDA dependent parameters were determined by ablation of matrix-matched standards. Quantification by IDA was compared against external calibration and was a more robust method, unaffected by sensitivity changes originating from plasma drifts or spontaneous plasma fluctuations.
Clases, D, Gonzalez de Vega, R, Bishop, D & Doble, P 2019, 'SEC-ICP-MS and on-line isotope dilution analysis for characterisation and quantification of immunochemical assays.', Analytical and bioanalytical chemistry, vol. 411, no. 16, pp. 3553-3560.View/Download from: Publisher's site
This study presents a novel size exclusion chromatography-inductively coupled plasma-mass spectrometry (SEC-ICP-MS) method for the characterisation and quantification of immunoassays with lanthanide-labelled antibodies. SEC-ICP-MS in combination with a double isotope dilution approach enabled facile validation of the antibodies' integrity, the determination of the batch to batch labelling efficiency, monitoring of each labelling step, and quantification of the immunocomplexes after incubation with the target protein. The addition of oxygen into the dynamic reaction cell improved the detection of sulphur as a marker for the antibodies and target protein via mass-shifting (LOD = 3.7 ng/mL), whilst maintaining sufficient sensitivity for the analysis of the lanthanides. Ultra-high performance liquid chromatography (UHPLC) SEC ensured a rapid chromatographic method with separation times under 7 min of the labelled and unlabelled antibodies, the immunocomplexes, and the unconjugated polymer used to lanthanide-label the antibodies. SEC calibration estimated the molecular weights of all peaks and provided valuable insights in immunochemical reactions and the stoichiometry of the reactants and products. A novel on-line isotope dilution analysis (IDA) enabled absolute quantification of sulphur and lanthanide signals and the protein of interest. The chromatographic separation of immunocomplexes and labelled antibodies allowed the simultaneous determination of the antibody/metal stoichiometry and target protein concentration from a single mass flow chromatogram. An immunoglobulin protein was quantified after incubation with an 153Eu-labelled primary polyclonal antibody. The procedure was validated with direct labelling of the target protein with 156Gd for parallel, simultaneous quantification. The concentration determined via direct labelling of the protein deviated 1.9% from the immunochemical approach employing 153Eu-labelled polyclonal antibodies. Graphical abstract.
Eijkelkamp, BA, Morey, JR, Neville, SL, Tan, A, Pederick, VG, Cole, N, Singh, PP, Ong, C-LY, Gonzalez de Vega, R, Clases, D, Cunningham, BA, Hughes, CE, Comerford, I, Brazel, EB, Whittall, JJ, Plumptre, CD, McColl, SR, Paton, JC, McEwan, AG, Doble, PA & McDevitt, CA 2019, 'Dietary zinc and the control of Streptococcus pneumoniae infection.', PLoS pathogens, vol. 15, no. 8.View/Download from: Publisher's site
Human zinc deficiency increases susceptibility to bacterial infection. Although zinc supplementation therapies can reduce the impact of disease, the molecular basis for protection remains unclear. Streptococcus pneumoniae is a major cause of bacterial pneumonia, which is prevalent in regions of zinc deficiency. We report that dietary zinc levels dictate the outcome of S. pneumoniae infection in a murine model. Dietary zinc restriction impacts murine tissue zinc levels with distribution post-infection altered, and S. pneumoniae virulence and infection enhanced. Although the activation and infiltration of murine phagocytic cells was not affected by zinc restriction, their efficacy of bacterial control was compromised. S. pneumoniae was shown to be highly sensitive to zinc intoxication, with this process impaired in zinc restricted mice and isolated phagocytic cells. Collectively, these data show how dietary zinc deficiency increases sensitivity to S. pneumoniae infection while revealing a role for zinc as a component of host antimicrobial defences.
González de Vega, R, Clases, D, Fernández-Sánchez, ML, Eiró, N, González, LO, Vizoso, FJ, Doble, PA & Sanz-Medel, A 2019, 'MMP-11 as a biomarker for metastatic breast cancer by immunohistochemical-assisted imaging mass spectrometry.', Analytical and bioanalytical chemistry, vol. 411, no. 3, pp. 639-646.View/Download from: Publisher's site
MMP-11 is a member of the matrix metalloproteinase family (MMPs) which are overexpressed in cancer cells, stromal cells and the adjacent microenvironment. The MMP protein family encompasses zinc-dependent endopeptidases that degrade the extracellular matrix (ECM), facilitating the breakdown of the basal membrane and matrix connective tissues. This function is believed to be important in cancer development and metastasis. This paper investigated a gold nanoparticle-based immunohistochemical assay to visualise the distribution of MMP-11 in human breast cancer tissues from eight patients with and without metastases by employing laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The expression of MMP-11 was increased and more heterogeneous in metastatic specimens compared to non-metastatic tumour samples. These findings demonstrate that imaging breast tumours by LA-ICP-MS may be a useful tool to aid the prognosis and treatment of breast cancer. As an example, samples of two patients are presented who were diagnosed with matching characteristics and grades of breast cancer. Although both patients had a similar prognosis and treatment, only one developed metastases.
Westerhausen, MT, Lockwood, TE, Gonzalez de Vega, R, Röhnelt, A, Bishop, DP, Cole, N, Doble, PA & Clases, D 2019, 'Low background mould-prepared gelatine standards for reproducible quantification in elemental bio-imaging.', The Analyst, vol. 144, no. 23, pp. 6881-6888.View/Download from: Publisher's site
Standard preparation for elemental bio-imaging by laser ablation-inductively coupled plasma-mass spectrometry is confounded by the chemical and physical differences between standard and sample matrices. These differences lead to variable ablation, aerosol generation and transportation characteristics and must be considered when designing matrix-matched standards for reliable calibration and quantification. The ability to precisely mimic sample matrices is hampered due to the complexity and heterogeneity of biological tissue and small variabilities in standard matrices and sample composition often negatively impact accuracy, precision and robustness. Furthermore, cumbersome preparation protocols may limit reproducibility and traceability. This work presents novel facile methods for the preparation of gelatine standards using both commercial and laboratory-made moulds. Surface roughness, thickness and robustness of the mould-prepared standards were compared against cryo-sectioned gelatine and homogenised brain tissue standards. The mould-prepared standards had excellent thickness accuracy and signal precision which allowed robust quantification, were easier to prepare and therefore easier to reproduce. We also compared gelatine standards prepared from a variety of animal sources and discuss their suitability to calibrate low level elemental concentrations. Finally, we present a simple method to remove background metals in gelatine using various chelating resins to increase the dynamic calibration range and to improve limits of analysis.
de Vega, RG, Sanchez, MLF, Eiro, N, Vizoso, FJ, Sperling, M, Karst, U & Medel, AS 2018, 'Multimodal laser ablation/desorption imaging analysis of Zn and MMP-11 in breast tissues.', Analytical and bioanalytical chemistry, vol. 410, no. 3, pp. 913-922.View/Download from: Publisher's site
Matrix metalloproteinases (MMPs) are a family of zinc-dependent endopeptidases. The main functions of these metalloproteinases are the degradation of the stromal connective tissue and basement membrane components. Recent data from model systems suggest that MMPs are involved in breast cancer (BC) initiation, invasion, and metastasis. Particularly, MMP-11 (stromelysin-3) is expressed in stromal fibroblasts adjacent to epithelial tumor cells, and high levels of this metalloproteinase were associated with tumor progression and poor prognosis of BC. Consequently, MMP-11 involved in these processes can be a candidate as a new potential prognostic biomarker in BC. Bioimaging techniques based on laser ablation/desorption and mass spectrometry are rapidly growing in biology and medicine for studies of biological systems to provide information of biomolecules (such as proteins, metabolites, and lipids) and metals with lateral resolution at the micrometer scale. In this study, matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) has been used for the first time to investigate the distribution of MMP-11 in human breast cancer tissues in order to show a possible correlation between cancerous and healthy samples, by differential proteomics and using such differences for possible cancer diagnosis and/or prognosis. Additionally, those human breast tissue samples were analyzed in parallel by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) in order to gather additional information about the elemental distribution of Zn and its possible associations with MMPs.
González de Vega, R, García, M, Fernández-Sánchez, ML, González-Iglesias, H & Sanz-Medel, A 2018, 'Protective effect of selenium supplementation following oxidative stress mediated by glucose on retinal pigment epithelium.', Metallomics : integrated biometal science, vol. 10, no. 1, pp. 83-92.View/Download from: Publisher's site
There are many conditions that affect the retina. However, diabetic retinopathy (RD) as a complication of Diabetes Mellitus continues to be the leading cause of blindness in working people globally. Diabetic retinopathy is an ocular complication of diabetes that is caused by the deterioration of the blood vessels that supply the retina, which has the consequence that the vision deteriorates irreversibly. The retina, and specifically the retinal pigment epithelium (RPE) is the only neural tissue that is exposed directly and frequently to light, which favors the oxidation of lipids that become extremely toxic to the cells of the retina. The RPE is a natural barrier playing an important role in the absorption of light and reduction of light scatter within the eye. In addition, the retina is the tissue that proportionally consumes more oxygen, which generates a high production of reactive oxygen species (ROS). The retina is particularly sensitive to hyperglycemia and oxidative stress. The eye tissues are enriched in certain antioxidants in the form of metabolic enzymes or small molecules. Since selenium is essential for regulating the activity of the enzymes involved in protection against oxidative stress, providing selenium to the ocular tissues could be useful for the treatment of different ocular pathologies. Thus, the aim of this study is to investigate the potential efficacy of selenium in human RPE against glucose-induced oxidative stress and its implications for GPx activity. Chromatographic techniques based on HPLC-ICP-MS will be applied in combination with isotope pattern deconvolution (IPD) to study the effects of selenium supplementation and hyperglycemia in an in vitro model of RPE cells.
González De Vega, R, Fernández-Sánchez, ML, Pisonero, J, Eiró, N, Vizoso, FJ & Sanz-Medel, A 2017, 'Quantitative bioimaging of Ca, Fe, Cu and Zn in breast cancer tissues by LA-ICP-MS', Journal of Analytical Atomic Spectrometry, vol. 32, no. 3, pp. 671-677.View/Download from: Publisher's site
© The Royal Society of Chemistry 2017. In recent years, several studies have shown that concentrations of essential trace elements naturally present in breast tissues (e.g. Ca, Fe, Cu and Zn) may be significantly increased in breast cancer tissues. This is not surprising because essential elements are responsible for a great number of metabolic and biological processes. The essential trace elements may play some major functions in life: stabilizers, elements of structure, elements for hormonal function and cofactors in enzymes. In any case, the role of trace elements in breast cancer is complex, because it affects many types of molecules, cells and tissues. The combination of analytical and immunehistochemical assays is crucial for better understanding of the role of essential trace elements in promoting tumor growth and migration. Bioimaging analytical techniques with adequate spatial resolution are today of crucial interest to investigate the spatial distribution of trace elements and correlate them with histological aspects in breast tissues. In this vein, in this particular study the application of laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) has been used for the first time to investigate the actual distribution of the essential trace bioelements (Ca, Fe, Cu and Zn) in breast cancer tissues, and its possible application for tumor diagnostic and prognostic purposes. As has been demonstrated in this study, the levels of Ca, Fe, Cu and Zn in the tumor area are significantly higher than the levels found in the non-tumor one, as well as, a heterogeneous distribution of the investigated metals.
Gonzalez de Vega, R, Luisa Fernandez-Sanchez, M, Carlos Fernandez, J, Alvarez Menendez, FV & Sanz-Medel, A 2016, 'Selenium levels and Glutathione peroxidase activity in the plasma of patients with type II diabetes mellitus', JOURNAL OF TRACE ELEMENTS IN MEDICINE AND BIOLOGY, vol. 37, pp. 44-49.View/Download from: Publisher's site
Gonzalez de Vega, R, Luisa Fernandez-Sanchez, M, Gonzalez Iglesias, H, Coca Prados, M & Sanz-Medel, A 2015, 'Quantitative selenium speciation by HPLC-ICP-MS(IDA) and simultaneous activity measurements in human vitreous humor', ANALYTICAL AND BIOANALYTICAL CHEMISTRY, vol. 407, no. 9, pp. 2405-2413.View/Download from: Publisher's site