Probing of bismuth antiulcer drug targets in H. pylori by laser ablation-inductively coupled plasma mass spectrometry

Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS)-based strategies applied for the analysis of metal-binding protein in biological samples: an update on recent advances

New analytical strategies for metal-binding protein facilitate researchers learning about how metals play a significant role in life. Laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS) offers many advantages for the metal analysis of biological samples and shows a promising future in protein analysis, but recent advances in LA-ICP-MS-based strategies for identifying metal-binding proteins via endogenous metals remain less updated yet. To present the current status in this field, the main analytical strategies for metal-binding proteins with LA-ICP-MS are reviewed here, including in situ analysis of biospecimens and ex situ analysis with gel electrophoresis. A critical discussion of challenges and future perspectives is also given. Multifarious laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS)-based strategies have been developed and applied to investigate the metal-binding proteins in biospecimens in situ or through gel electrophoresis ex situ over the past decades, facilitating researchers disclosing how essential metals are implicated in life or what proteins toxic metals will target.

Metalloproteomics for Biomedical Research: Methodology and Applications

Metals are essential components in life processes and participate in many important biological processes. Dysregulation of metal homeostasis is correlated with many diseases. Metals are also frequently incorporated into diagnosis and therapeutics. Understanding of metal homeostasis under (patho)physiological conditions and the molecular mechanisms of action of metallodrugs in biological systems has positive impacts on human health. As an emerging interdisciplinary area of research, metalloproteomics involves investigating metal-protein interactions in biological systems at a proteome-wide scale, has received growing attention, and has been implemented into metal-related research. In this review, we summarize the recent advances in metalloproteomics methodologies and applications. We also highlight emerging single-cell metalloproteomics, including time-resolved inductively coupled plasma mass spectrometry, mass cytometry, and secondary ion mass spectrometry. Finally, we discuss future perspectives in metalloproteomics, aiming to attract more original research to develop more advanced methodologies, which could be utilized rapidly by biochemists or biologists to expand our knowledge of how metal functions in biology and medicine. Expected final online publication date for the Annual Review of Biochemistry, Volume 91 is June 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Medicinal chemistry and biomedical applications of bismuth-based compounds and nanoparticles

Bismuth as a relatively non-toxic and inexpensive metal with exceptional properties has numerous biomedical applications. Bismuth-based compounds are used extensively as medicines for the treatment of gastrointestinal disorders including dyspepsia, gastric ulcers and H. pylori infections. Recently, its medicinal application was further extended to potential treatments of viral infection, multidrug resistant microbial infections, cancer and also imaging, drug delivery and biosensing. In this review we have highlighted the unique chemistry and biological chemistry of bismuth-209 as a prelude to sections covering the unique antibacterial activity of bismuth including a description of research undertaken to date to elucidate key molecular mechanisms of action against H. pylori, the development of novel compounds to treat infection from microbes beyond H. pylori and the significant role bismuth compounds can play as resistance breakers. Furthermore we have provided an account of the potential therapeutic application of bismuth-213 in targeted alpha therapy as well as a summary of the biomedical applications of bismuth-based nanoparticles and composites. Ultimately this review aims to provide the state of the art, highlight the untapped biomedical potential of bismuth and encourage original contributions to this exciting and important field.

Metalloproteomics for molecular target identification of protein-binding anticancer metallodrugs

Proteomics has played an important role in elucidating the fundamental processes occuring in living cells. Translating these methods to metallodrug research ('metalloproteomics') has provided a means for molecular target identification of metal-based anticancer agents which should signifcantly advance the research field. In combination with biological assays, these techniques have enabled the mechanisms of action of metallodrugs to be linked to their interactions with molecular targets and aid understanding of their biological properties. Such investigations have profoundly increased our knowledge of the complex and dynamic nature of metallodrug-biomolecule interactions and have provided, at least for some compound types, a more detailed picture on their specific protein-binding patterns. This perspective highlights the progression of metallodrug proteomics research for the identification of non-DNA targets from standard analytical techniques to powerful metallodrug pull-down methods.

Characterization of membrane-bound metalloproteins in the anaerobic ammonium-oxidizing bacterium "Candidatus Kuenenia stuttgartiensis" strain CSTR1

Membrane-bound metalloproteins are the basis of biological energy conservation via respiratory processes, however, their biochemical characterization is difficult. Here, we followed a gel-based proteomics and metallomics approach to identify membrane-associated metalloproteins in the anaerobic ammonium-oxidizing "Candidatus Kuenenia stuttgartiensis" strain CSTR1. Membrane-associated protein complexes were separated by two dimensional Blue Native/SDS gel electrophoresis and subunits were identified by mass spectrometry; protein-bound metal ions were quantified from the gel by connecting either a desolvating nebulizer system or laser ablation to inductively coupled plasma triple quadrupole mass spectrometry (ICP-QqQ-MS). We identified most protein complexes predicted to be involved in anaerobic ammonium oxidation and carbon fixation. The ICP-QqQ-MS data showed the presence of Fe and Zn in a wide range of high molecular weight protein complexes (230-800 kDa). Mo was prominently found in gel slices with proteins of a size of 500-650 kDa, whereas Ni was only found using the desolvating nebulizer system in the protein range of 350-500 kDa. The detected protein complexes and their metal content were consistent with genome annotations. Gel-based metalloproteomics is a sensitive and reliable approach for the characterization of metalloproteins and could be used to characterize many multimeric metalloprotein complexes in biological systems.

Metalloproteomics in conjunction with other omics for uncovering the mechanism of action of metallodrugs: Mechanism-driven new therapy development

Medicinal inorganic chemistry has been largely stimulated by the clinic success of platinum anticancer drugs. An array of metal-based drugs (e.g. platinum, gold, bismuth, and silver) are currently used clinically for the treatment of various diseases. Integrating multiomics approaches, particularly metalloproteomics, with other biochemical characterizations enables comprehensive understanding of cellular responses of metallodrugs, which in turn will guide the rational design of a new drug and modification of the presently used drugs. This review aims to summarize the recent progress in this area. We will describe the technology platforms and their applications for uncovering the mechanisms of action of metallodrugs, for which remarkable advances have been achieved recently. Moreover, we will also highlight the application of newly generated knowledge for the development of novel therapeutic strategies.

Gel electrophoresis in combination with laser ablation-inductively coupled plasma mass spectrometry to quantify the interaction of cisplatin with human serum albumin

Cisplatin and its second and third generation analogues are widely used in the treatment of cancer. To study their reactions with proteins, we present a method based on SDS-PAGE separation and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) for platinum detection in the reaction between human serum albumin (HSA) and cisplatin. We developed matrix-matched standards of HSA/cisplatin mixtures and used them to quantify the amount of adducts formed at different HSA:cisplatin ratios. We noted that cisplatin incubation with HSA resulted in the formation of higher order HSA n-mers, depending on the amount of cisplatin added. This caused a depletion of the HSA dimer bands, while the majority of HSA was present as the monomer. Inducing the formation of such higher molecular weight species may have an impact on the mode of action of metallodrugs.

Competition for Iron Between Host and Pathogen: A Structural Case Study on Helicobacter pylori

Helicobacter pylori (H. pylori) is a highly successful bacterial pathogen, which colonizes the stomach of more than half of the world's population. To colonize and survive in such an acidic and inhospitable niche, H. pylori cells have evolved complex mechanisms to acquire nutrients from human hosts, including iron, an essential nutrient for both the pathogens and host cells. However, human cells also utilize diverse strategies in withholding of irons to prevent the bacterial outgrowth. The competition for iron is the central battlefield between pathogen and host. This mini-review summarizes the updated scenarios of the battle for iron between H. pylori and human host from a structural biology perspective.

Microbial Metalloproteomics

Metalloproteomics is a rapidly developing field of science that involves the comprehensive analysis of all metal-containing or metal-binding proteins in a biological sample. The purpose of this review is to offer a comprehensive overview of the research involving approaches that can be categorized as inductively coupled plasma (ICP)-MS based methods, X-ray absorption/fluorescence, radionuclide based methods and bioinformatics. Important discoveries in microbial proteomics will be reviewed, as well as the outlook to new emerging approaches and research areas.

Metallomic and metalloproteomic strategies in elucidating the molecular mechanisms of metallodrugs

Advances in the mechanistic studies of metallodrugs by metallomic and metalloproteomic approaches will improve our understanding of the mechanism of action and allow more metallodrugs to be developed.

Current and potential applications of bismuth-based drugs

: Bismuth compounds have been used extensively as medicines and in particular for the treatment of gastrointestinal ailments. In addition to bismuth's well known gastroprotective effects and efficacy in treating H. pylori infection it also has broad anti-microbial, anti-leishmanial and anti-cancer properties. Aspects of the biological chemistry of bismuth are discussed and biomolecular targets associated with bismuth treatment are highlighted. This review strives to provide the reader with an up to date account of bismuth-based drugs currently used to treat patients and discuss potential medicinal applications of bismuth drugs with reference to recent developments in the literature. Ultimately this review aims to encourage original contributions to this exciting and important field.

Functional disruption of HypB, a GTPase of Helicobacter pylori, by bismuth

Bismuth (Bi(3+)) binds equal molar amounts of HypB from Helicobacter pylori at the conserved metal site with a dissociation constant of 0.94 (±0.25) × 10(-17) μM, and concomitantly induces the protein dimerization similarly to Ni(2+). Excess Bi(3+) causes HypB further oligomerization, leading to HypB GTPase dysfunction. The results extend our understanding on the inhibitory mechanism of bismuth drugs against the pathogen.

Helicobacter pylori neutrophil-activating protein: From molecular pathogenesis to clinical applications

Helicobacter pylori (H. pylori) neutrophil-activating protein (HP-NAP) was originally identified as a virulence factor of H. pylori for its ability to activate neutrophils to generate respiratory burst by releasing reactive oxygen species. Later on, HP-NAP was also found to be involved in the protection of H. pylori from DNA damage, supporting the survival of H. pylori under oxidative stress. This protein is highly conserved and expressed by virtually all clinical isolates of H. pylori. The majority of patients infected with H. pylori produced antibodies specific for HP-NAP, suggesting its important role in immunity. In addition to acting as a pathogenic factor by activating the innate immunity through a wide range of human leukocytes, including neutrophils, monocytes, and mast cells, HP-NAP also mediates adaptive immunity through the induction of T helper cell type I responses. The pro-inflammatory and immunomodulatory properties of HP-NAP not only make it play an important role in disease pathogenesis but also make it a potential candidate for clinical use. Even though there is no convincing evidence to link HP-NAP to a disease outcome, recent findings supporting the pathogenic role of HP-NAP will be reviewed. In addition, the potential clinical applications of HP-NAP in vaccine development, clinical diagnosis, and drug development will be discussed.

Characterization of selenium incorporation into wheat proteins by two-dimensional gel electrophoresis-laser ablation ICP MS followed by capillary HPLC-ICP MS and electrospray linear trap quadrupole Orbitrap MS

A method has been developed for a rapid and precise location of selenium-containing proteins in large two-dimensional (2D) electrophoresis gels. A sample was divided into four aliquots which were analyzed in parallel by 1D isoelectric focusing electrophoresis (IEF)-laser ablation (LA) inductively coupled plasma mass spectrometry (ICP MS), 1D sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS PAGE)-LA ICP MS, and, in duplicate, by 2D IEF-PAGE. On the basis of the 1 D electropherograms obtained, areas supposed to contain the largest concentrations of Se were subjected to LA ICP MS imaging to locate precisely the position of Se-containing proteins which were then identified in the parallel 2D gel by electrospray Orbitrap MS/MS. The method was applied to the identification and semiquantitative determination of selenium storage proteins in wheat. MS evidence is presented for the Se-S substitution in plants not only in methionine but also in cysteine.

The actions of bismuth in the treatment of Helicobacter pylori infections: an update

Helicobacter pylori causes various gastric diseases, such as gastritis, peptic ulcerations and gastric cancer. Bismuth-based triple or quadruple therapies have been commonly recommended for the treatment of H. pylori infections. Up to now, the molecular mechanisms by which bismuth inhibits the growth of H. pylori are far from clear. The present concise review intends to cover the most recent reports and discoveries in the field of the inhibitory mechanism of bismuth against H. pylori as well as the bacterial protective response to drug treatment, which will help us to further understand the molecular mechanisms underlying the actions of metal-based drugs and stimulate further development of effective anti-bacterial drugs.

Recent advances in bioinorganic chemistry of bismuth

Bismuth has been used in medicine for over two centuries for the treatment of various diseases, in particular for gastrointestinal disorders, owing to its antimicrobial activity. Recent structural characterization of bismuth drugs provides an insight into assembly and pharmacokinetic pathway of the drugs. Mining potential protein targets inside the pathogen via metallomic/metalloproteomic approach and further characterization on the interactions of bismuth drugs with these targets laid foundation in understanding the mechanism of action of bismuth drugs. Such studies would be beneficial in rational design of new potential drugs.