Metals and metalloids play essential roles in cancer biology, influencing redox balance, epigenetic regulation, immune responses, and cell death throughout tumour development, progression, and resistance to therapy. Despite this broad biological relevance, the systematic clinical integration of metallomics into oncology remains in its early stages. This review introduces the Cancer Metallome Continuum (CMC), a framework illustrating how metallomic reprogramming evolves from cancer initiation through progression to therapy-resistant states, and evaluates the analytical, systems-level, and translational approaches needed to test it. In early stages of cancer, toxic metals such as As, Cd, hexavalent chromium [Cr(VI)], and Ni induce oxidative stress, epigenetic modifications, and DNA repair defects. During progression, dyshomeostasis of essential metals creates tumour-specific dependencies. For example, Fe accumulation can support tumour growth, while tumour cells concurrently engage anti-ferroptotic programs; Cu contributes to angiogenesis and kinase signalling, and Zn transporter networks regulate apoptosis and immune responses. Under treatment pressure, tumours adapt by rewiring metal transporters, upregulating metallothionein buffering, and suppressing metal-dependent cell death pathways, including ferroptosis and cuproptosis. Translational advances include selenium-based prognostic panels with replicated evidence in breast cancer (SCAN-B) and colorectal cancer (CORSA), Cu-chelation trials, and spatially resolved metallodrug imaging. The strongest human evidence currently supports Se-based prognostic panels (replicated across breast and colorectal cancer cohorts) and the feasibility of biomarker-guided Cu depletion (a Phase II single-arm trial), while spatial integration and artificial intelligence/machine learning (AI/ML) applications remain at the proof-of-concept or emerging stages. Clinical translation will require tighter control of preanalytical variability, prospective multicentre validation, and standardized reporting.
Zinc is an essential trace element, yet how graded dietary zinc intake reshapes tissue-specific distributions of zinc and other essential metals remains incompletely understood. This study investigated the impact of dietary zinc ranging from deficiency to high supplementation on the metallomic profile of C57BL/6 J mice. Mice were fed one of five zinc diets for 3 or 6 weeks, after which zinc status and related elements (copper, iron, manganese, calcium, and magnesium) were quantified in serum and multiple tissues by inductively coupled plasma-optical emission spectrometry, alongside expression of zinc transporter and metal-related genes in intestinal segments. Tissue zinc responses differed strongly across organs. Serum zinc increased only after prolonged supplementation, the colon and small intestine showed rapid and pronounced shifts with both deficiency and excess, brain and skeletal muscle regions displayed selective sensitivity, and liver and kidney zinc remained comparatively stable, consistent with strong homeostatic control. Dietary zinc did not deplete tissue copper but instead showed positive associations between zinc and copper in several tissues. We also observed co-ordinated and tissue-dependent relationships between zinc and iron, manganese, calcium, and magnesium, which challenges the traditional view that mineral interactions are uniformly antagonistic. When we integrated elemental and gene expression data and explicitly linked metal responses to measured tissue zinc levels, we identified segment-specific and transporter-specific adaptations that support a model in which dietary zinc reorganizes local and systemic mineral balance. This reorganization reflects both changes in tissue zinc levels and additional regulatory mechanisms in metal transport and storage that are not apparent from whole-tissue zinc measurements alone.
Zinc is essential for cellular homeostasis and acts both as a structural element and a secondary messenger in intracellular signalling. While the role of SLC39 (former ZIP) family transporters in breast cancer biology is intensively studied, the signalling function of SLC30 family transporters (former ZnT) remains insufficiently explored. This study investigates the involvement of SLC30 transporters in oestrogen receptor-positive (ER+) breast cancer. Bioinformatic and experimental analyses revealed that SLC30 transporters, particularly SLC30A1, SLC30A5, and SLC30A9, regulate the PTP/AKT/ESR1 pathway, contributing to hormone-independent ESR1 activation. Zn-dependent inhibition of PTP phosphatases modulates kinase signalling, promoting proliferation. Notably, high SLC30 expression correlates with improved survival, but serves as a negative prognostic marker under tamoxifen treatment. Here, we evidence that ESR1 directly represses SLC30 transcription and that zinc transporters form a regulatory feedback loop sustaining ER+ breast tumour progression. These findings position SLC30 transporters as active participants in signalling cascades, offering novel targets for therapeutic intervention in ER+ breast cancer.
Isotopes of calcium (Ca) in blood and urine have been introduced as a potential clinical tool for monitoring bone mineral balance (BMB). While several works support the ability of Ca isotope composition (δ44/42Ca) to capture a shift in BMB in response to external forcings (e.g. bed rest) or disease (e.g. osteoporosis), the influence of an individual's demographic, health status, diet or lifestyle on δ44/42CaUrine/Blood remains largely unconstrained. To gauge the effects of several variables among these four broader categories, we present a population study of δ44/42CaUrine from 103 individuals (age 18-76). Age is negatively correlated with δ44/42CaUrine, and we identify three other attributes (active vitamin D deficiency, vegetarian diet, and being post-menopausal) that lead to systematic differences in an individual's δ44/42CaUrine. Fluctuations in Ca reabsorption generate significant intra-individual δ44/42CaUrine variability. Within a typical range of reabsorption rates, however, the initial isotope composition (δ44/42CaSerum) exerts the strongest control on inter-individual δ44/42CaUrine variability. Using a simple Rayleigh model to express isotopic fractionation associated with Ca reabsorption in the kidneys, we find that a fractionation factor of 0.99972 reproduces the range of isotope ratios and excretion values for several, healthy individuals across three different studies and nearly a 30-year age span. Importantly, δ44/42CaUrine variations in three post-menopausal women from three separate studies cannot be explained by the same model, pointing to a different mechanistic control of δ44/42CaUrine in these subjects.
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.
THGP [3-(trihydroxygermyl) propanoic acid], an organogermanium compound, has been confirmed to exert multifaceted effects in mammalian and eukaryotic cells. Focusing on the characteristic trihydroxyl germanium moiety of THGP, we aimed to discover its novel pharmacological abilities and effects against multidrug-resistant Acinetobacter baumannii, a prokaryote with critical implications on global public health. In all assays, spectrometric determinations (OD) were conducted using a 96-well microtiter plate: OD489 for β-lactamase activity, OD600 for bacterial mass, OD570 for biofilm mass, OD340 for alcohol dehydrogenase (ADH) activity, and OD460 for dehydrogenases-NAD(P)-NAD(P)H system activity. THGP was observed to exhibit β-lactamase activity inhibition ability, which actually presents synergistic effects with cephem antibiotics against A. baumannii. We also revealed ADH activity inhibition ability, which contributes to the antiproliferative effect of THGP, a weak organic acid, against A. baumannii. However, low permeability of THGP through the bacterial cell because of its high hydrophilicity seemed to attenuate this intracellular effect. Furthermore, THGP was postulated to possess preventive effects on biofilm formation at sub-MIC (below the minimum inhibitory concentration) via an unknown mechanism. To our knowledge, this study is the first to report the antimicrobial effects of an organogermanium compound and demonstrates the inhibition abilities of THGP against two ubiquitous enzymes in pathogenic bacteria. However, the findings of this study are insufficient for clinical applications. Further studies are warranted to promote the development of clinically useful organogermanium compounds. Nevertheless, our findings provide important baseline information for future exploratory studies.
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.
Understanding how chalcogen elements taken up by biological systems change their chemical speciation is essential for elucidating their intracellular behaviour. However, knowledge of the uptake and transformation of selenium and tellurium oxyanions in unicellular algae remains limited. In this study, selenium and tellurium oxyanions in different oxidation states (VI or IV) were added to two unicellular algae, Chlamydomonas reinhardtii and Pseudococcomyxa simplex, and their intracellular accumulation and chemical speciation were systematically investigated. X-ray absorption fine structure analysis revealed that both selenium and tellurium underwent intracellular reduction irrespective of their initial oxidation states. However, the extent of reduction, accumulation efficiency, and final chemical speciation differed markedly depending on both the oxidation state of the added oxyanion and the algal species, indicating shared yet species-dependent intracellular transformation patterns. In particular, tetravalent oxyanions (selenite and tellurite) underwent more rapid reduction and exhibited higher cellular accumulation than the corresponding hexavalent species in both algae, although the extent and kinetics of reduction differed markedly between species. Scanning and transmission electron microscopy demonstrated that selenium was immobilized as spherical elemental nanoparticles, whereas tellurium formed needle-like metallic nanorods within algal cells. Under hexavalent selenate exposure, higher-valent and organoselenium species remained detectable, and the formation of elemental selenium nanoparticles was limited. These results demonstrated speciation- and species-dependent intracellular transformation and accumulation of selenium and tellurium in unicellular algae, providing chemical speciation-based insights into algal chalcogen metabolism and detoxification processes.
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.
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.
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.
Zinc is an essential trace element with antioxidant and signaling functions critical to cardiac physiology. This study investigated the role of zinc in myocardial ischemia-reperfusion (IR)-induced cardiac damage using a rat model, and whether zinc deficiency induced by intermittent hypoxia (IH) exacerbates cardiac injury. Regional IR was performed in isolated rat hearts, and zinc concentrations were measured in coronary effluents. Plasma zinc status was assessed following 14- or 35-day IH exposure (1-min cycles alternating 21% and 5% FiO₂, 8 h/day). The cardioprotective effects of intracoronary zinc administration with the ionophore pyrithione were evaluated based on arrhythmias, infarct size, and contractile recovery. Myocardial IR induced significant zinc release upon reperfusion (615.7 ± 78.2 nM vs. 374.5 ± 40.3 nM pre-reperfusion, P < 0.01). Zinc administration during reperfusion reduced arrhythmia duration (358.0 ± 61.7 sec vs. 559.9 ± 31.6 sec, P < 0.01) and improved myocardial recovery. IH exposure led to reduced plasma zinc levels (10.3 ± 0.5 µM vs. 13.0 ± 1.2 µM, P = 0.057) and significantly increased infarct size following IR (43.9 ± 4.2% vs. 29.2 ± 4.3%, P < 0.05). Zinc-pyrithione treatment during reperfusion abolished the deleterious effects of IH on infarct size. IH-induced zinc deficiency exacerbates cardiac vulnerability to IR injury, while zinc restoration through targeted administration mitigates this damage. Zinc's protective effects may involve antioxidant action, calcium homeostasis, and signaling modulation. Zinc plays a critical role in limiting IR-induced cardiac damage. Zinc supplementation during reperfusion may offer therapeutic benefit, particularly in conditions associated with chronic IH, such as obstructive sleep apnea.
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.
From bacteria to humans, the highly conserved Cu- and Zn-containing superoxide dismutase (Cu/Zn SOD) plays a pivotal role in free radical biology. By using Cu to disproportionate superoxide at rates that approach diffusion limits, Cu/Zn SODs are premier antioxidants. Interestingly, during eukaryotic evolution, several derivatives of the Cu/Zn SOD polypeptide appeared, where the Cu and/or Zn sites were lost and in some cases, Cu/Zn SOD-like sequences were replicated or fused to other protein domains. Such variations of Cu/Zn SOD include the CCS Cu chaperone, fungal Cu-only SODs, and animal CSRP (Cu-only SOD repeat proteins). Here we review the unique biophysical properties and biological functions of these Cu/Zn SOD-like proteins. CCS appeared early in eukaryotic evolution, where a primordial Cu/Zn SOD lost its Cu site and was fused to other Cu-binding domains, creating a dual Cu/molecular chaperone for intracellular Cu/Zn SOD. In the Opisthokont supergroup of eukaryotes that formed fungi and animals, a Cu/Zn SOD lost its Zn binding capacity and structural loop VII, forming Cu-only SODs of fungi and tandemly amplified Cu-only SODs in animal CSRP. Cu-only SODs and Cu-binding CSRPs are efficient SODs, and with lowered Cu-binding affinities, they have evolved to function exclusively outside the cell. Cu-only SODs promote virulence of pathogenic fungi, and recent studies have implicated a role for amphibian CSRP in tissue regeneration, a process involving reactive oxygen species. We have just begun to understand how nature has diversified the Cu/Zn SOD template to create new molecules for metal and free radical biology.
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.
Chronic exposure to copper ions, Cu(II), induces organ-specific oxidative damage and mitochondrial dysfunction, with distinct temporal and biochemical profiles across tissues. This study evaluated the protective effects of vitamin E (α-tocopherol) against Cu(II)-induced phospholipid and protein oxidation, redox imbalance, and bioenergetic disruption in rats. Cu(II) treatment led to early lipid peroxidation in the brain, heart, and lung, followed by delayed oxidative damage in the liver and kidney. Vitamin E effectively prevented phospholipid oxidation in all organs, but its protection against protein oxidation and mitochondrial respiratory impairment was organ-specific and time-dependent. Mitochondrial respiration declined in brain and heart tissues, with partial recovery in the heart after prolonged vitamin E supplementation. Electron transport chain activity was altered by Cu(II), notably with increased complex I activity in the liver and decreased complex I and II activity in the lung and kidney. Vitamin E failed to prevent these changes in most tissues. Glutathione modulation revealed adaptive redox responses in the lung and oxidative depletion in kidney. These findings highlight the complexity of Cu(II)-induced oxidative damage and the limited but significant protective role of vitamin E, emphasizing the need for targeted antioxidant strategies to preserve mitochondrial integrity and cellular function under metal-induced stress.
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.
Phosphorus (P) is central to biology, yet it remains unclear whether P limitation acts as an isolated nutrient constraint or as a perturbation to a dynamical elemental network. We tested this using the rainbow trout liver cell line RTL-W1 by manipulating phosphorus supply (0%, 10%, and 100% of normal supply; P0, P10, and P100) and quantifying proliferation, protein content, metabolic activity, membrane integrity, and multielement composition. Phosphorus supply significantly altered cell proliferation and protein accumulation, with higher P supporting greater growth. Metabolic activity was affected by P supply, whereas membrane integrity remained largely stable, indicating altered allocation rather than generalized cellular damage. Compositional ionomic analysis revealed that phosphorus perturbation restructured the multielement network. At Day 3, treatment effects were strongest for P, K, and S. By Day 6, additional elements, including Sr and Mn, exhibited coordinated shifts relative to the P100 reference. Compositional data analysis showed that elemental imbalances shifted through time, consistent with flux rebalancing in an open system rather than static homeostasis. If phosphorus limitation were mechanistically independent, multielement composition would remain stable aside from P itself. Instead, phosphorus perturbation induced coordinated shifts across the ionome, consistent with rebalancing in open material systems.
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.
A method for quantitative speciation analysis of residual gadolinium in skin following gadolinium-based contrast agent exposure was developed for the first time. Polyethersulfone was identified as a suitable filter material for these compounds, allowing complete recovery of spiked contrast agents. In contrast, decreasing recoveries with increasing charge of the compound were observed for regenerated cellulose and cellulose triacetate as filter materials. The developed method entailed the utilization of bead beating for tissue homogenization, and the release of yttrium from ceramic beads was shown to result in the gadolinium transmetalation of a linear gadolinium-based contrast agent. A three-step centrifugation of homogenized skin samples, followed by filtration, was performed to extract hydrophilic species for analysis. In combination with using the respective europium chelates as internal standards, this approach enabled the complete recovery of macrocyclic contrast agents from spiked tissue. Quantitative speciation analysis of the biological extracts was conducted by means of anion exchange chromatography hyphenated to inductively coupled plasma-mass spectrometry. This analytical strategy applied to rat skin tissue after repeated administration of macrocyclic contrast agents showed that about a quarter of the residual gadolinium in skin tissue was present in the aqueous extract one month after the last injection. The majority of this water-soluble gadolinium was confirmed by speciation analysis to be the intact administered contrast agent. The presented methodological framework can serve as a first step towards exhaustive speciation analysis of residual gadolinium in skin matrix.