Metallomics最新文献

Zinc ions are highly abundant in pancreatic islet tissue, and multiple lines of evidence link loss of zinc homeostasis to poor glucose regulation in both type 1 and type 2 diabetes. Two major islet zinc-binding proteins, insulin and metallothionein, play crucial roles in beta cell function and glucose regulation. Here we used X-ray fluorescence microscopy (XFM) to map zinc and five additional elements (Cl, K, Ca, Fe, and Cu) to compare the metallome of exocrine, peri-islet and islet regions in young and old, non-diabetic control and diabetic (db/db) mice. We also determined the main forms of zinc found in pancreatic tissue using X-ray absorption near-edge structure (XANES) spectroscopic imaging. This allowed investigation of the relationship between zinc speciation and its protein ligands using correlative immunofluorescent imaging to assess whether zinc coordination may play a role in diabetes pathology. The anticipated depletion of zinc in young diabetic islets was accompanied by a significant decrease in insulin expression and increase in metallothionein expression. A parallel change in the contribution of cysteine vs histidine zinc speciation was also observed. Counter-intuitively, zinc abundance and speciation appeared to normalise in old diabetic animals with more advanced disease, despite large differences in labile zinc-binding protein content. These results are consistent with disrupted zinc coordination, where metallothionein-regulated muffling to minimise ionic activity is overwhelmed and zinc binds to unidentified ligands in histidine-like conformations. This opens future study questions focussed on the complex interplay between labile zinc, metallothionein, and oxidative mechanisms that may interfere with normal zinc homeostasis.

Zinc ions (Zn2+) are the second most abundant trace metal ion in the brain of rodents and primates, often serving functions as a structure-stabilizing element or catalytic role. There is an additional pool of Zn2+, ∼15% of total brain Zn2+, which exists in a labile chemical form in a specific subset of glutamatergic neurons ('zinergic' or 'zincergic' neurons). The labile pool of Zn2+ is now well established to be critical for healthy memory function, with disturbance to the labile Zn2+ pool implicated in diminished memory performance during the ageing process or neurodegeneration. The chemical form of Zn2+ in the labile Zn2+ pool has however, remained unknown, largely due to the difficulty of imaging metal speciation for 'spectroscopically silent' metals such as Zn2+. In this study, we have developed X-ray absorption near edge structure (XANES) spectroscopic protocols to enable chemically specific imaging of Zn2+ speciation in murine brain (hippocampal) tissue. The protocols capitalise on the unique sensitivity of the XANES spectral region to metal ion coordination environment, enabling a direct in situ measurement of metal speciation. Key findings of our method development are characterisation of the effects of sample preparation on metal speciation, and revelation that Zn2+ coordination with histidine is likely to be the dominant coordination environment of the labile Zn2+ pool in the murine hippocampus.

Zinc stable isotope ratios (δ66Zn) are increasingly applied in fields such as archaeology, ecology and medicine, owing to their sensitivity to dietary variations. Despite their growing use, isotopic data for foods, particularly plants, remains limited. This has led to contradictory interpretations of animal isotopic patterns (e.g. browsers vs. grazers) due to notable gaps in the literature. To address this issue, δ66Zn values were analyzed from 138 organic plant samples of various origins and species. Using different digestion protocols for sample preparation, we obtained reliable δ66Zn values for 99 of these samples. We documented limited Zn isotope fractionation during incomplete digestion and during the zinc (Zn) purification and recovery using column chromatography. Notably, we observed higher δ66Zn values in cereals, pseudo-cereals, and legumes compared to leaves, nuts, and seeds. These findings elucidate dietary isotopic differences in herbivores and highlight the utility of δ66Zn in tracing the adoption of agriculture in archaeology, where cereals and legumes became the primary dietary sources of Zn. This study fills in critical data gaps and underscores the importance of plant δ66Zn isotopic baselines in dietary reconstructions.

Raman spectroscopy is a label-free, chemically selective technique increasingly employed to probe intracellular biochemical changes associated with drug exposure. Herein, Raman microspectroscopy was applied to evaluate the in vitro responses of MCF-7 (cancerous) and MCF-12A (noncancerous) breast cells to a series of cytotoxic copper(II) (Cu(II)), manganese(II) (Mn(II)), and silver(I) (Ag(I)) complexes containing dicarboxylate and 1,10-phenathroline ligands. Their spectral responses were analysed using principal component analysis (PCA), establishing distinct molecular fingerprints for each metal complex, reflecting divergent mechanisms of action (MOAs). The Cu(II) complexes produced signatures consistent with canonical apoptosis, including reduced DNA backbone vibrations at ∼785 cm⁻¹ and protein conformational changes at ∼1660 cm⁻¹. The Mn(II) complexes demonstrated features of oxidative stress (∼1450 and 1180 cm⁻¹) and spectral features associated with autophagy (∼718 cm⁻¹), in addition to signatures of an apoptotic response like those observed by the Cu(II) analogues, supporting a multimodal mechanism. In contrast, Ag(I) complexes elicited distinct biochemical alterations suggestive of non-canonical pathways, including markers linked to cholesterol metabolism at ∼703 cm⁻¹ and steroid-related activity indicated by multiple features > 1600 cm⁻¹. These spectral distinctions shed light on the role of different types of metal centres in modulating downstream cellular responses and underscore Raman spectroscopy's utility in resolving subtle yet functionally relevant biochemical differences across this series of complexes. Collectively, these findings provide novel insights into the MOAs of this class of complex and support the broader application of Raman spectroscopy to inform future design and evaluation of metal-based cytotoxic agents.

In this study, we report the synthesis and detailed characterization of four novel bidentate (N, N) ligands incorporating a 2-(methylthio)pyrimidine moiety and their fac-tricarbonylrhenium(I) complexes (ReB1-ReB4 and ReB1Aq) with the general formula fac-[Re(CO)3(N,N)X]n+, with X = Cl- or H2O and n = 0 or 1. Designed to integrate biologically relevant functionalities, these complexes exhibited promising multifunctional bioactivity. Cytotoxicity assays demonstrated moderate activity (IC50 = 11-78 µM) on various human cancer cell lines, with certain derivatives showing notable selectivity toward the Colo205 line. Most of the chlorido complexes effectively inhibited the replication of Herpes simplex virus type 2, while ReB4 displayed significant antibacterial activity against Staphylococcus aureus, including methicillin-resistant strains (MIC = 12.5-25 µM), and demonstrated biofilm inhibition. Aqueous stability of these organometallic complexes was thoroughly investigated, and complexes ReB2 and ReB3 containing a pyrimidine and a thiazole ring, respectively, gradually decompose in aqueous media, correlating with a decline in anticancer activity. Ligand-exchange processes were observed, in which the chlorido co-ligands were replaced by water, thus affecting the solubility and lipophilicity. The aqua complex ReB1Aq exhibited a low chloride affinity, and the pKa of the coordinated water molecule was obtained to be ∼8. Its interaction with human serum albumin was investigated in detail and was found to be dominated by non-covalent interactions, indicating that no coordination bond formation occurs with the protein.

Knee osteoarthritis (OA) is a leading cause of disability worldwide. Oxidative stress (OS), enhanced by exposure to heavy metals such as cadmium (Cd), may contribute to its progression. Cd, present in tobacco smoke, disrupts chondrocyte viability, redox balance, and essential metal homeostasis. This study aimed to determine whether Cd exposure, particularly through smoking, influences the development and severity of knee OA by affecting antioxidant defense, metallothioneins (MTs) expression, arginase II activity, and trace metal levels in blood, synovial fluid (SF), and cartilage. Fifty-one OA patients were stratified by smoking status (non-smokers, ex-smokers, smokers). Cd and other metals were quantified by ICP-MS, along with OS markers (MDA, MGO, AOPPs), antioxidant enzymes (GST, GGT, CAT), prooxidant enzymes (MPO, arginase II), and metallothinein-1A and 2A (MT-1A/2A) levels. Non-parametric tests assessed correlations between Cd and redox markers. Smokers exhibited higher Cd in blood (0.34 ng/mL) and cartilage (26.07 ng/g), with increased GST, GGT, MDA, and AOPPs. Cd correlated positively with MDA (rho = 0.319, P = 0.033). In SF, elevated CAT, GGT, and arginase II activity were found in patients with high Cd levels (Q3), alongside increased MT-2A expression in smokers (P = 0.018). Cd exposure was also linked to an imbalance of essential metals such as selenium. These findings suggest that Cd, mainly from smoking, exacerbates OS, alters redox enzyme activity, induces MT-2A, and disrupts metal homeostasis, potentially mediating OA pathogenesis. Longitudinal studies are warranted to confirm its causal role in disease progression.

Molecular mass spectrometry was utilised for the first time to gather information of formed compounds consisting of tetrathiomolybdate and Cu in the context of Wilson's disease. Electrospray ionisation-mass spectrometry was used to elucidate four in vitro-formed tetrathiomolybdate-Cu compounds, including MoS4Cu-, (MoS4)2Cu3-, (MoS4)3Cu5-, and (MoS4)4Cu7-. Based on the ions' net charges, it could be concluded that Cu(II) had been reduced to Cu(I), which then binds to tetrathiomolybdate. By increasing the potential applied to the electrospray ionisation source, it was observed that the heavier compounds fragment into MoS4Cu-, which hints to the possibility of tetrathiomolybdate and Cu(I) form oligomeric species in solution, with MoS4Cu- being a possible base structure. Trapped ion mobility spectrometry-mass spectrometry in conjunction to collision-induced dissociation was used to conclude that the heavier species can also fragment into the lighter ones, corroborating the assumption of a oligomeric species. Further fragmentation experiments provided additional insight into the behaviour of these compounds in the gas phase, as product ions could be identified which necessitate the reduction of Mo(VI) during or after fragmentation of these structures. Using glutathione as a model compound, it could be shown that tetrathiomolybdate and Cu(I) can bind to glutathione disulfide, which was likely formed by a Cu-initiated oxidation of glutathione. The identification of various tetrathiomolybdate-Cu species as well as tetrathiomolybdate-Cu-glutathione disulfide demonstrates that molecular mass spectrometry can be used to elucidate reactions between tetrathiomolybdate, Cu, and biomolecules related to Wilson's disease.

Inorganic drugs have a huge impact in medicine, yet their solution behavior in presence of solvents for biological testing is often underestimated, even for clinically established agents. Speciation, hydrolysis, and redox processes can profoundly affect efficacy, safety, and reproducibility, with direct implications for both in vitro and in vivo testing. Here we present a proof-of-concept study highlighting the importance of systematic stability assessment prior to biological evaluation. Four representative metallodrugs were selected to capture diverse oxidation states, coordination geometries, and activation mechanisms: the ruthenium(III) complex NAMI-A, the platinum(II) drug oxaliplatin, the platinum(IV) derivative Hex-Pt, and the experimental gold(I) complex Npx-Au. Although limited in number, this panel demonstrates that meaningful insights can only be obtained through an integrated, multi-technique approach. By combining methods such as NMR spectroscopy, UV-Vis spectroscopy, and HPLC-MS, early degradation events can be reliably detected, optimal storage conditions defined, and misleading experimental outcomes avoided. Our findings emphasize that rigorous stability profiling over time is not optional but essential for accurate dosing, reproducibility, and correct interpretation of preclinical assays. This work establishes a framework for incorporating systematic solution stability evaluation into the development and experimental use of metallodrugs, ensuring more reliable translation from bench to clinic.

Oral leukoplakia is oral potentially malignant disorder with an unclear etiology. Emerging evidence indicates a link between metal dyshomeostasis and carcinogenesis. This study is the first to compare serum concentrations of calcium (Ca), magnesium (Mg), selenium (Se), copper (Cu), zinc (Zn), iron (Fe), lead (Pb) and manganese (Mn), as well as the peripheral blood immunological characteristics, between patients with oral leukoplakia and healthy controls, aiming to explore the potential association between metal dyshomeostasis and oral leukoplakia. This cross-sectional-case-control study recruited 89 participants at West China Hospital of Stomatology, including 59 patients with oral leukoplakia and 30 healthy controls. The concentrations of Ca, Mg, Se, Cu, Zn, Fe, Pb and Mn were measured by inductively coupled plasma-mass spectrometry (ICP-MS), and peripheral blood immunological characteristics were quantified using standard clinical chemistry methods. Compared with the control group, the serum Se level in oral leukoplakia patients was significantly decreased and negatively correlated with the degree of dysplasia. However, the Pb level was significantly increased. Patients with oral leukoplakia had abnormal immune function, with significantly decreased percentages of CD3 + T cell and CD8 + T cells, and significantly increased levels of IgA and antinuclear antibodies. Moreover, the Pb was significantly negatively correlated with cellular immunity, while Se was positively correlated with the count of CD8 + T cells. This study indicates a potential association between metal dyshomeostasis and oral leukoplakia, which may be mediated through the immune function, especially abnormal cellular immunity. These findings provide new insights into the etiology and treatment of oral leukoplakia.

X-ray absorption spectroscopy (XAS) is a technique which is frequently used in metallomics research, providing a valuable tool for the elucidation of element-specific electronic and geometric structural information. Recent decades have seen the development of related synchrotron-based X-ray techniques with enhanced analytical capabilities, including X-ray emission spectroscopy (XES), resonant inelastic X-ray scattering (RIXS), and high energy resolution fluorescence detected X-ray absorption spectroscopy (HERFD-XAS). With appropriate experimental configuration, HERFD-XAS can generate spectra with significantly improved spectroscopic resolution and background rejection compared to conventional XAS, providing a substantial advantage in the analysis of dilute analytes in biological samples. These improvements arise from the capability to interrogate selected fluorescence lines with the use of multiple crystal analyzers, minimizing the effects of core-hole lifetime broadening. Herein, we review a range of existing and emerging applications of HERFD-XAS for the study of metals and metalloids in biology and medicine. Direct comparisons of conventional XAS and HERFD-XAS spectra highlight the substantial improvements in resolution, and greater potential for the interpretation of metal speciation in complex and dilute biological samples. We also discuss current challenges with the design of HERFD-XAS experiments.