The expanding landscape of the thiol redox proteome

The expanding landscape of the thiol redox proteome

Abstracts / Toxicology Letters 258S (2016) S39–S53 W03-5 Moving MS(i) closer to surgery: The need to improve pre-, intra and post-operative clinical ...

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Abstracts / Toxicology Letters 258S (2016) S39–S53

W03-5 Moving MS(i) closer to surgery: The need to improve pre-, intra and post-operative clinical diagnostics


W04-2 Targets and consequences of alkylation damage by reactive electrophiles Angela Mally

Tiffany Porta ∗ , Keely Pierzchalski, Klara Scupakova, Anne L. Bruinen, Florian P.Y. Barré, Pierre Maxence Vaysse, Flora Olivier, Benjamin Balluff, Berta Cillero-Pastor, Ron M.A. Heeren M4I Institute, University of Maastricht, Maastricht, The Netherlands Mass spectrometry imaging (MSI) is becoming more and more popular in pre-clinical and clinical research. Particularly, matrixassisted laser desorption/ionization MSI has proven its suitability for establishing molecular classification of different tissue-types, including tumors, to improve the accuracy of diagnosis. As an example, a clear pre/post-operative diagnosis of cholangiocarcinoma (a primary liver adenocarcinoma originating from the bile duct) – routinely done by histological examination of tissue – is challenging and often not possible due to the amount of available tissue and/or confounding factors like inflammation. Herein, we suggest that MSI provides accurate tissue classification based on molecular information that allows distinguishing between tumoral and non-tumoral tissue to improve patient management. MSI has also been demonstrated powerful to study drug metabolism and tissue distribution in diverse applications; e.g. drug-induced renal toxicity or effect of corticosteroid used to treat pain and inflammation caused by osteoarthritis. More recently, intraoperative molecular diagnostic based on MS has recently gained attention from the medical field as it offers the possibility of in vivo, in situ and real-time mass spectrometric tissue analysis. In the context of liver surgery; real-time information would guide and optimize surgical resection within the anatomic boundaries reducing the incidence of incomplete tumor resection. To perform successful intraoperative diagnostics, the bottleneck remains the building of a database, containing tissue-specific molecular signatures, and adequate statistical model to provide accurate tissue classification. Herein, we demonstrate the capabilities of rapid evaporative ionization mass spectrometry to differentiate between non-tumor and hepatocellular carcinoma tumor in transgenic ASV-B mouse model, through the real-time MS analysis of smoke released during electrosurgical dissection. Workshop W04: Protein targets of reactive intermediates: Linking chemistry to biology and adverse outcome W04-1 Introduction/Chair Angela Mally a,b,∗ , Hilmi Orhan a,b a b

Ege University, Izmir, Turkey University of Würzburg, Würzburg, Germany

Department of Toxicology, University of Würzburg, Würzburg, Germany In the past, comprehensive understanding of mechanisms of toxicity involving protein binding of reactive intermediates has been limited by the fact that identification of critical protein targets has proven extremely difficult. Recently, however, novel approaches for the separation and determination of covalent drugprotein adducts have enabled identification of target proteins for a number of model compounds. Despite these advances, understanding which target proteins may be critical for disruption of cell homeostasis and toxicity remains challenging since binding to some proteins may function as a mechanism of detoxification/inactivation of reactive electrophiles to prevent damage and loss of function of proteins which may be less abundant but perhaps more important for cell survival. The presentation will use examples from literature and our own work on furan to illustrate strategies and recent progress in mapping biological processes and toxicity pathways modulated by reactive electrophiles. W04-3 The expanding landscape of the thiol redox proteome Jing Yang National Center for Protein Sciences, Beijing, China The nucleophilic thiol group allows cysteines to undergo a broad range of chemical modifications, including redox reactions, alkylation, and metal binding, which are important for protein structure, localization, regulation. However, methodological limits have so far prevented a proteome-wide analysis of the substrates and specific sites of these modifications. We apply chemical probes and mass spectrometry-based chemoproteomics to investigate protein targets of oxidation-related thiol modifications, including total cysteine oxidation, S-sulfenylation and S-alkylation by lipidelectrophile in complex proteomes. Using this strategy, we are able to (1) quantify changes of over 6000 reactive cysteine residues in proteomes in response to exogenous hydrogen peroxide stimulation, (2) site-specifically map and quantify over 1000 unstable S-sulfenylation events in cells, and (3) directly identify and quantify ∼400 S-alkylations by lipid-derived electrophiles in cells. These studies not only greatly expand the catalogue of thiol proteins that undergo these modifications in cells, but also suggest novel redox mechanisms that contribute to key biological functions of several proteins. For example, SIRT6, a member of a conserved family of NAD+ -dependent deacetylases, may exert redox control of HIF1A transcriptional activity through reversible formation of disulfidelinked SIRT6–HIF1A complex. Taken together, these studies provide a new view of the landscape of thiol redox modifications in proteomes and suggests new hypotheses for future exploration of redox signaling and oxidative stress.