Metallomics最新文献

Zinc is an essential transition metal that participates in many biological processes. In C. elegans, excess zinc is stored in lysosomes in intestinal cells; this process involves increasing the expression of the zinc transporter CDF-2 and remodeling of lysosomes characterized by an increase in the volume of the expansion compartment. To determine if this is a more general property, we investigated other metals. Here we report that lysosomes are remodeled in response to excess copper, manganese, and cadmium, with each metal causing an increase in the volume of the expansion compartment. Mutants with a reduced number of lysosomes were hypersensitive to growth retardation caused by excess copper and manganese, suggesting metal toxicity is prevented by metal sequestration in lysosomes. We developed a method to analyze isolated lysosomes by X-ray Fluorescence Microscopy; zinc, copper, and manganese are detectable in the lumen of lysosomes, and the concentration of zinc in the lysosomes increased substantially in worms exposed to excess dietary zinc. To further analyze copper, we examined localization of CUA-1.1, a copper transporter that moves copper into the lumen of lysosomes. Like the zinc transporter CDF-2, CUA-1.1 localizes to both the acidified and expansion compartments in excess copper. These results indicate that the same intestinal lysosomes store both zinc and copper. Furthermore, lysosome remodeling characterized by an increase in volume of the expansion compartment is not specific to excess zinc but is a more general phenomenon during metal storage in lysosomes.

Staphylococcus aureus and Escherichia coli remain major concerns in global public health, posing clinical challenges due to their adaptability, virulence, and biofilm-mediated persistence. The continued emergence of drug-resistant strains necessitates the development of new antimicrobial compounds. In this study, we evaluated the multifunctional potential of a hetero-ligated, thiolato-bridged dinuclear metallacyclic Mn(I)-based CO-releasing compound (S-MnC), analysing its antibacterial, antibiofilm, molecular, and target-binding efficacies against S. aureus and E. coli. The antibacterial potential of S-MnC was confirmed by a significant decrease in bacterial growth, biofilm biomass, matrix integrity, motility, and structural integrity. Our results further confirmed its anti-adhesive potential, demonstrating the depletion of intracellular free thiols and an increase in reactive oxygen species. Additionally, S-MnC displayed safe hemolysis levels. ADMET analysis indicated a good balance of drug-likeness properties. Molecular docking studies suggested potential binding sites of S-MnC to molecular targets such as bacterial DNA Gyrase B, SaeR, SaeS, and SarA of S. aureus, as well as DNA Gyrase B and SdiA of E. coli, suggesting the antivirulence mechanisms mediated by S-MnC. In this study, we report, for the first time, the antibacterial and antibiofilm activities of S-MnC against both Gram-negative, E. coli, and Gram-positive, S. aureus, and its binding affinity to multiple molecular and virulence targets.

Cyclometalated Iridium(III) complexes have emerged as one of the most versatile classes of photosensitizers for photodynamic therapy (PDT), owing to their tunable photophysics, high phosphorescence quantum yields, and intrinsic capacity for real-time optical imaging. However, the clinical translation of conventional PDT remains limited by nonspecific activation, poor selectivity, and off-target phototoxicity. The dynamic and heterogeneous tumour microenvironment (TME)- defined by anomalous pH, elevated Glutathione (GSH) levels, malfunctioned redox homeostasis, enzyme overexpression, and irregular vascularization, which thus offers an opportunity to engineer next-generation photosensitizers that respond selectively to these cancer-specific stimuli. This review aims to explore recent advances in stimuli-responsive and theranostic cyclometalated iridium(III) systems designed to achieve anticancer activity in a spatiotemporal manner. We discuss the molecular design principles and mechanistic bases of TME-, redox-, enzyme-, and light-triggered activation, along with emerging multi-stimuli architectures that enhance the robustness in complexes. The review further focuses on the way Ir(III) Complexes unite therapy and diagnostics. Due to their inherent luminescence, redox characteristics, and excited-state behaviour, these complexes enable simultaneous imaging, ROS production, microenvironment sensing, and real-time monitoring of treatment responses. By correlating structural features with activation pathways and biological outcomes, the review seeks to provide a mechanistic framework for designing smart Ir(III)-based PDT agents with improved selectivity, reduced systemic toxicity, and enhanced therapeutic precision.

Cisplatin is a DNA-targeting chemotherapeutic. Here we investigate how the cisplatin-damaged gene (CDG) loci are linked to specific protein-driven signalling pathways. A human high mobility group protein 1 box a-based affinity probe has been constructed and 1,2-cisplatin-crosslinked DNA has been isolated before high throughput gene sequencing. Cisplatin damage to specific genes has been mapped in human lung cancer cells, and a total of 16 216 CDGs mapped with fold-enrichment >1.5. Surprisingly, bioinformatics analysis demonstrates that cisplatin targets most of the human protein kinase (PK) and phosphatase genes and is involved in 300 important cell signalling pathways (-log p > 4). The most associated key signalling pathways are sperm motility and protein kinase A. Notably, cisplatin damaged 85% (440) of human PK genes and 81% (110) of human protein phosphatase genes. This implies that cisplatin may disrupt protein phosphorylation signalling genome-wide, evidenced by a significant decrease in expression of a series of key PK genes.

Mutations in the copper (Cu) transporter ATP7A cause a spectrum of X-linked diseases, including Menkes Disease, Occipital horn syndrome, and distal hereditary motor neuropathy (dHMNX). We previously generated a conditional knock-in mouse model of dHMNX expressing Atp7aT985I, the murine orthologue of the human T994I variant identified in dHMNX patients. Although Atp7aT985I mice did not develop overt motor degeneration, affected males showed a trend toward reduced Cu levels in the peripheral nervous system (PNS). The high-affinity copper transporter Ctr1, encoded by Slc31a1, regulates Cu uptake, and ubiquitous heterozygosity for Slc31a1 (Ctr1+/-) has been reported to limit Cu availability in the nervous system without impairing motor performance. In this study, we genetically restricted Cu availability in Atp7aT985I mice by crossing them with Ctr1+/- animals. Atp7aT985I/Ctr1+/- males exhibited significantly reduced Cu levels in both the central nervous system and PNS compared to wild-type littermates. At 6 months of age, behavioural testing and histopathological assessment revealed mild motor deficits and axonal loss, preferentially affecting small-caliber fibres exclusively in the Cu-restricted Atp7aT985Imales. Tandem mass tag-based proteomics of sciatic nerve identified significant changes linked to energy metabolism, cytoskeletal integrity, and cellular stress responses. Together, these data show that limiting Cu availability unmasks a dHMNX-like phenotype in Atp7aT985I/Ctr1+/- mice, demonstrate the critical role of Cu availability in maintaining peripheral axons and suggest that reduced Cu in motor neurons contributes to axonal degeneration in dHMNX.

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.

The effects on metal accumulation in various organs of the Wistar rat were analyzed after applying a protocol of dietary restriction to half the quantity of food consumed by the mother prior to mating, during gestation, lactation, and applied also to the offspring, postweaning. The present paper reports a follow-up study that tested whether changes of metal ion distribution in the main organs of 60-day-old rats of both sexes exposed to this treatment were reproduced when the dietary restriction was extended another month, resulting in 90-day-old rats. Here, additional analyses of serum metal ions and serum proteomics were included. Results confirmed that copper normally stored in the kidney of animals fed ad libitum accumulates instead in the liver and pancreas of animals from the dietary restriction group, without any change in serum. Consistently, proteomic analysis revealed no changes in ceruloplasmin and instead showed hallmarks of intravascular hemolysis in the dietary restricted group of rats. Iron was low in spleen and high in liver and pancreas. Thus, dietary restriction led to physiological redistribution of iron and copper between different organs. We discuss these changes in the framework of systemic metal homeostasis.

Molecular mass spectrometry was utilized for the first time to gather information of formed compounds consisting of tetrathiomolybdate (TTM) and Cu in the context of Wilson's disease (WD). Electrospray ionization (ESI)-mass spectrometry was used to elucidate four in vitro-formed TTM-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 TTM. By increasing the potential applied to the ESI source, it was observed that the heavier compounds fragment into MoS4Cu-, which hints to the possibility of TTM and Cu(I) forming 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 an 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 TTM and Cu(I) can bind to glutathione disulfide, which was likely formed by a Cu-initiated oxidation of glutathione. The identification of various TTM-Cu species as well as TTM-Cu-glutathione disulfide demonstrates that molecular mass spectrometry can be used to elucidate reactions between TTM, Cu, and biomolecules related to WD.

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 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.