Search Results (329)

Cadmium is widely recognized as an important environmental toxicant that may give rise to kidney dysfunction, bone disease, and cancer in humans and animals. Kidney dysfunction occurs at very low exposures and is often considered as the most sensitive or critical effect. Cadmium exposures of concern occur in many countries. In low- and middle-income countries with small-scale mining, excessive exposure to cadmium and other metals occurs in occupational and environmental settings. This is of particular importance in view of the growing demand for metals in global climate change mitigation. Since the 1970s, the present authors have contributed evidence concerning the role of metallothionein and other factors in influencing the toxicokinetics and toxicity of cadmium, particularly as it relates to the development of adverse effects on kidneys in humans and animals. The findings gave a background to the development of biomarkers employed in epidemiological studies, demonstrating the important role of metallothionein in protection against cadmium-induced kidney dysfunction in humans. Studies in cadmium-exposed population groups demonstrated how biomarkers of kidney dysfunction changed during 8 years after drastic lowering of environmental cadmium exposure. Other epidemiological studies showed the impact of a good zinc status in lowering the prevalence of cadmium-related kidney dysfunction. Increased susceptibility to Cd-induced kidney dysfunction was shown in a population with high exposure to inorganic arsenic when compared with a group with low such exposure. Several national and international organizations have used part of the reviewed information, but the metallothionein-related biomarkers and the interaction effects have not been fully considered. We hope that these data sets will also be included and improve risk assessments and preventive measures. Full article

Heavy metals are among the most persistent and bioaccumulative pollutants in marine ecosystems, posing significant toxicological threats to fish via complex molecular and cellular disruptions. This review synthesizes current knowledge on the cascade of mechanistic responses in marine fish following HM exposure, which includes oxidative stress, modulation of antioxidant responses, activation of detoxification systems, DNA damage, inflammation, apoptosis, neuroendocrine disruption, and ultimately, cellular energy imbalance. In addition to established pathways, the review highlights recent advances in mechanistic understanding and biomarker development, including cellular stress responses, epigenetic regulation, metal homeostasis mechanisms, and novel molecular indicators. These mechanisms support the development of an integrated biomarker framework that combines classical indicators (e.g., antioxidant enzymes, metallothionein) with next-generation endpoints (e.g., miRNA profiles, gene-level responses of metal transporters or stress chaperones, epigenetic alterations). The interpretation of biomarker responses requires consideration of the exposure context, environmental variables, and physiological status to ensure accurate assessment of sublethal toxicity in field settings. By bridging mechanistic understanding with biomonitoring relevance, this review provides a comprehensive foundation for advancing molecular tools in pollution monitoring and risk assessment. Special emphasis is placed on biomarkers specific to heavy metal exposure, enhancing their diagnostic value relative to general stress indicators. Full article

Background: Rheumatoid arthritis (RA) is a chronic autoimmune disorder that predominantly affects synovial joints, leading to inflammation, pain, and progressive joint damage. Despite therapeutic advancements, the molecular basis of established RA remains poorly defined. Methods: In this study, we conducted an untargeted plasma proteomic analysis using two-dimensional differential gel electrophoresis (2D-DIGE) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) in samples from RA patients and healthy controls in the discovery phase. Results: Significantly (ANOVA, p ≤ 0.05, fold change > 1.5) differentially abundant proteins (DAPs) were identified. Notably, upregulated proteins included mitochondrial dicarboxylate carrier, hemopexin, and 28S ribosomal protein S18c, while CCDC124, osteocalcin, apolipoproteins A-I and A-IV, and haptoglobin were downregulated. Receiver operating characteristic (ROC) analysis identified CCDC124, osteocalcin, and metallothionein-2 with high diagnostic potential (AUC = 0.98). Proteins with the highest selected frequency were quantitatively verified by multiple reaction monitoring (MRM) analysis in the validation cohort. Bioinformatic analysis using Ingenuity Pathway Analysis (IPA) revealed the underlying molecular pathways and key interaction networks involved STAT1, TNF, and CD40. These central nodes were associated with immune regulation, cell-to-cell signaling, and hematological system development. Conclusions: Our combined proteomic and bioinformatic approaches underscore the involvement of dysregulated immune pathways in RA pathogenesis and highlight potential diagnostic biomarkers. The utility of these markers needs to be evaluated in further studies and in a larger cohort of patients. Full article

Utilizing a multi-biomarker approach, we assessed the potential adverse effects of pollutants on subcellular responses in the digestive gland of the freshwater mussel Unio crassus from a historically contaminated lowland section (KIZ) of the river Mrežnica compared to its less impacted upstream karstic section (REF) and their seasonality (spring vs. autumn). This approach accounted for the diverse modes of action of pollutants by including biomarkers of metal exposure (metallothioneins, MT), general stress (total cytosolic proteins, TP), antioxidative capacity (catalase, CAT; glutathione, GSH; glutathione-S-transferase, GST), oxidative damage (malondialdehyde, MDA), and neurotoxicity (acetylcholinesterase, AChE). Only in spring, MT concentrations were 15% higher at the REF site (4.38 ± 1.06 µg mg proteins⁻¹) compared to the KIZ site (3.69 ± 0.63 µg mg proteins⁻¹), likely related to elevated Cd bioaccumulation due to the karstic substrate. Regardless of the season, mussels from KIZ showed consistently lower TP and GSH, with significantly higher CAT, GST, and MDA levels, indicating elevated stress, activation of antioxidant defenses, and oxidative damage from chronic exposure to pro-oxidant pollutants, including metal(loid)s and organic contaminants (e.g., ibuprofen, nicotine). Compared to the REF site, AChE activity at the KIZ site was higher in late spring and lower in early autumn, indicating seasonal variability in AChE activity at the contamination-impacted location driven by fluctuating exposure to neurotoxicants, such as drugs and insecticides. Overall, biomarker responses indicated that mild historical pollution, reinforced by current low-capacity sources, has an observable impact on mussel health, posing long-term risks to sediment-dwelling aquatic organisms. Full article

The progressive commercial deployment of multi-walled carbon nanotubes (MWCNTs) raises concerns about their terrestrial ecotoxicity. We exposed adult Cornu aspersum (150 snails; five replicates of three animals per time-point) to 50 mg L⁻¹ MWCNT-dosed Lactuca sativa for 30 days and quantified five mechanistic biomarkers alongside survival. Hemocyte spread-cell area increased by 48% (from 243 ± 22 µm² at day 0 to 360 ± 18 µm² at day 14, p < 0.001). Lysosomal membrane stability (neutral red retention) fell twofold within 72 h and to 10 min by day 30 (controls ≈ 60 min), indicating early, persistent destabilization. Micronucleus frequency rose above the ecogenotoxic threshold of 5‰ after 7 days, peaking at 8.3 ± 0.7‰ on day 14 (p < 0.01). Hepatopancreas metallothionein concentrations doubled by day 3 (2.1 ± 0.3 vs. 1.0 ± 0.2 µg g⁻¹ ww in controls) and remained >150% of control throughout exposure, consistent with metal impurity mobilization. Acetylcholinesterase activity in cephalic tissue declined by 50% after 7 days and by 73% after 30 days, revealing sustained neurotoxicity. Despite these pronounced sub-individual disturbances, cumulative mortality reached only 19% at day 30, suggesting substantial, but finite, physiological compensation. Collectively, the data demonstrate that a 50 mg L⁻¹ dietary load of MWCNTs elicits rapid cytotoxic, genotoxic, and neurotoxic responses in C. aspersum that precede overt lethality, underscoring the utility of this gastropod and the chosen biomarker suite for monitoring nanotube contamination in agro-ecosystems and food-grade snail farming. Full article

Cadmium (Cd) contamination in agricultural soils severely threatens rice production and food safety. To address this issue, this study developed transgenic rice lines co-expressing three Vitis vinifera genes: the ABCC transporter Vvmrp1 and metallothioneins Vvmt1 and Vvmt2. AlphaFold computational modeling confirmed the conserved ABCC-type transporter domain in VvMRP1. Under hydroponic conditions, transgenic rice showed remarkable Cd tolerance, surviving 30 mM Cd (lethal to wildtype, WT) without growth penalties, and exhibited 62.5% survival at 1 mM Cd vs. complete wild-type mortality. Field-relevant Cd exposure (1 mM) reduced Cd accumulation to 35.8% in roots, 83% in stems, and 76.8% in grains compared to WT. Mechanistic analyses revealed that Vvmrp1 mediates cellular Cd efflux while Vvmt1 and 2 chelate free Cd ions, synergistically inhibiting Cd translocation. Transgenic plants also maintained better Fe, P, and Mg homeostasis under Cd stress. This study pioneers the co-expression of a transporter with metallothioneins in rice, demonstrating their complementary roles in Cd detoxification without pleiotropic effects from endogenous gene modification. The findings provide an effective genetic strategy for cultivating low-Cd rice in contaminated soils, offering significant implications for food safety and sustainable agriculture. Full article

Metals are natural components of the lithosphere, whose amounts and bioavailability are increasing in many areas due to their continuous release from both natural sources and intensive human activities. Some metals are essential or beneficial for living organisms, while others are non-essential and potentially toxic. When present at higher concentrations, even essential and beneficial metal ions can become harmful to all forms of life. Bacteria, unicellular organisms that have been exposed to metals since the earliest stages of life on Earth, have evolved metabolic pathways involving essential metals as well as diverse strategies to cope with metal toxicity. In the domain Bacteria, two main strategies have been identified: (i) metal exclusion, which includes cell wall sequestration and immobilization of metals in extracellular exopolysaccharides, siderophores, and other soluble microbial products, as well as (ii) metal tolerance, involving intracellular sequestration of metals (e.g., by metallothioneins, or low molecular weight thiols) as well as enzymatic conversion of metals to less toxic forms and/or its active efflux. Microorganisms possessing such adaptive traits are considered valuable agents for potential application in medicine, environmental sciences, and bioengineering (e.g., bioremediation and/or biomining). Full article

Background: Acne vulgaris, a prevalent inflammatory skin disorder, stems from factors like Cutibacterium acnes overgrowth, inflammation dysregulation, and immune dysfunction. Clinically, acne severity inversely correlates with serum zinc (Zn) levels, and oral Zn supplementation shows efficacy. Lactic acid bacteria are capable of converting inorganic Zn into organic forms via biological transformation, potentially generating Zn-enriched bacteria as superior Zn delivery vehicles. Methods: In this study, a Zn-deficient acne mouse model was established through dietary Zn restriction combined with intradermal C. acnes injection. The therapeutic effects of orally administered Zn-containing supplements, including Zn-enriched Bifidobacterium longum subsp. longum CCFM1195 (Zn-CCFM1195), were systematically evaluated through multiple parameters: histopathological evaluation of skin lesions, cutaneous inflammatory and oxidative stress markers, serum Zn concentration, and gene expression levels of pathway-associated proteins. Results: Induction of C. acnes led to decreased serum Zn levels (14.98 μmol/L in Control vs. 9.71 μmol/L in Model) and skin metallothionein content, causing Zn imbalance. Zn deficiency caused increased levels of lesion elevation (9.23 in Model vs. 10.53 in Zn-deficient Model), IL-17A, TNF-α, and MMP9 in skin, thereby exacerbating the inflammatory response in C. acnes-induced mice. Zn supplementation alleviated inflammatory responses and oxidative stress in Zn-deficient acne-like mice. Notably, inactivated Zn-CCFM1195 exhibited superior efficacy to ZnSO₄, significantly reducing lesion diameter and decreasing cutaneous levels of IL-1β, IL-17A, and MDA while enhancing GSH-Px activity. Similarly, viable Zn-CCFM1195 treatment significantly decreased IL-17A and enhanced GSH-Px activity compared with ZnSO₄ treatment. Furthermore, Zn supplementation downregulated the expression of TLR2, IκBα, and IKKβ, which may exert its anti-acne effect by regulating related pathways. Conclusions: Zn deficiency exacerbates skin inflammation, whereas Zn supplementation, particularly with Zn-CCFM1195, alleviates acne vulgaris through anti-inflammatory and antioxidant effects. Full article

The subcellular partitioning of trace elements (TEs) may depend on their binding preferences, although few field data are available from mining-impacted areas. Northern pike and lake whitefish were collected from different aquatic systems located in the Yellowknife mining area (Northwest Territories, Canada) to examine the subcellular partitioning of TEs in liver cells. Elements belonging to metal classes based on binding affinities were considered: A (Ce, La), borderline (As, Pb), and class B (Ag, Cd). Measurements in the metal-detoxified fractions (granule-like structures and heat-stable proteins and peptides) and in the putative metal-sensitive fractions (heat-denatured proteins, mitochondria and microsomes, and lysosomes) revealed marked differences among metal classes. In both fish species, Cd and Ag accumulated more as detoxified forms (higher than 50%, likely bound to metallothionein-like proteins) than La and Ce (not more than 20%). The two borderline TEs (As and Pb) showed an intermediate behavior between classes A and B. Similar proportions were found in the “sensitive” subcellular fractions for all TEs, where quantitative ion character-activity relationships (QICARs) indicated the covalent index and electronegativity as predictors of the TE contribution in this compartment. This study supports the use of classes of metals to predict the toxicological risk of data-poor metals in mining areas. Full article

This study aims to evaluate the tolerance of an endophytic fungus isolated from the fibrous roots of Gentiana yunnanensis Franch. to arsenic (As) and elucidate the underlying physiological and molecular mechanisms. The filamentous fungus is identified as Cladosporium cladosporioides based on morphological characteristics and phylogenetic tree analysis, belonging to the family Moniliaceae and Phyla Hyphomycetes. The tolerance of C. cladosporioides to As(V) was assessed by measuring its biomass under varying concentrations of As(V). The fungus exhibited remarkable As(V) tolerance, with an EC₅₀ value of 2051.94 mg/L, and accumulated high concentrations of As in its mycelium. Subcellular distribution analysis revealed that As was predominantly localized in the cell wall fraction, with levels 4.06 times higher than those in the non-cell wall fraction. Notably, the concentrations of total organic As and As(III) in the mycelium were 852.75 μg/g and 24.94 μg/g, respectively, with conversion ratios of 76.64% and 2.24%. The organic As levels significantly surpassed both As(V) and As(III) concentrations in all cellular fractions (cell wall and non-cell wall components), demonstrating particularly efficient As transformation in C. cladosporioides. Under As(V) stress, the membrane antioxidant system, including superoxide dismutase (SOD), metallothionein (MT), glutathione (GSH), and melanin, was activated and significantly enhanced to mitigate oxidative damage. Transcriptomic analysis identified 4771 differentially expressed genes (DEGs; 2527 upregulated), including highly expressed As-responsive genes (CcArsH_1, CcARR_1, CcARR_3, CcGST_1, and CcGST_3). Strong correlations emerged between As speciation (total/organic/As(V)/As(III)), antioxidant levels, and DEG expression patterns. Taken together, these findings demonstrate that C. cladosporioides employs a multi-faceted As detoxification strategy involving subcellular distribution and reductive transformation (As(V) to As(III)/organic As), antioxidant system enhancement, transcriptomic adaptations, and integrated defense strategy. This work highlights C. cladosporioides potential for As bioremediation and elucidates As accumulation mechanisms in G. yunnanensis. Full article

Metallothioneins (MTs) are low-molecular-weight metal-binding proteins potentially involved in the detoxification of heavy metals, protection against oxidative stress, and other biological processes. This study examined progesterone’s influence on Mt gene expression in rat adipose tissue. Wistar rats (females and males) received 100 mg of progesterone per rat. MT mRNA and protein levels were quantified by real-time PCR and Western blotting methods. Using radioimmunoassay, the serum progesterone level was measured. In this study, progesterone administration to female rats led to a 2.5-fold increase in serum progesterone concentration and significant increases in MT-1, MT-2A mRNA, and protein levels in inguinal WAT (WATi), compared to untreated female rats. RU 486 (progesterone receptor antagonist) abolished progesterone’s influence on Mt-1 and Mt-2A gene expression in female WATi. Progesterone administration did not alter the level of Mt-3 gene expression in WATi or Mt-1 and Mt-2A in retroperitoneal WAT or brown adipose tissue in female rats. Full article

Background/Objectives: Laryngeal squamous cell carcinoma represents one of the most common head and neck cancers with a five-year survival rate that, despite diagnostic and therapeutic advances, has not shown any significant improvement in recent decades. Oxidative stress, generated by an imbalance between reactive oxygen species and cellular antioxidant systems, is considered a central mechanism in the carcinogenesis of laryngeal squamous cell carcinoma, causing DNA damage and genomic alterations. Methods: This prospective observational paired case–control study focused on the evaluation of antioxidant proteins, such as superoxide dismutase, catalase, heme-oxygenase 1, vimentin, metallothionein, and nuclear factor erythroid 2-related factor 2, in cancer tissues from fifteen patients with laryngeal squamous cell carcinoma, using adjacent healthy tissues as controls. Results: The results show a statistically significant overexpression of all proteins analyzed in cancer tissues compared to controls, with relevant correlations between specific biomarkers and clinical characteristics, age, sex, smoking habits, and degree of tumor differentiation. Conclusions: These preliminary studies, while limited by sample size and the complexity of molecular regulation, indicate that the overexpression of antioxidant enzymes in laryngeal squamous cell carcinoma tissues, along with their correlations with key clinical parameters, underscores a context-dependent role of oxidative stress in tumor progression. A deeper understanding of oxidative stress mechanisms could contribute to advance personalized management strategies for laryngeal squamous cell carcinoma, potentially improving treatment outcomes and patient prognosis. Full article

Heavy metals such as Cu and Cd are important pollutants. Quillay (Quillaja saponaria) is a tree species endemic to Chile that is of worldwide commercial interest due to its saponins. It can grow on contaminated sites. However, the biological mechanisms underlying its defensive responses remain elusive. This study aimed to characterize Quillay plants under Cu and Cd stress and identify mechanisms controlling their interaction with these metals. We subjected six-month-old plants to Cu (75, 150, and 300 μM) and Cd (20, 40, and 80 μM) in hydroponics for a week and assessed growth, metal accumulation, saponin production, and the expression of a suite of stress-induced genes. Those genes are related to phytochelatins (PCS) and metallothioneins (MT), the antioxidant system (GS and GR), and metal transporters (COPT1). The results indicated that both metals were accumulated mainly in roots, with 339.9 and 433.8 mg/kg DW, for Cd and Cu, respectively, exhibiting a metal excluder pattern. Cd increased the length of the principal root. Higher doses of Cd and Cu augmented the saponin content (62.8% and 41.2% compared to control, respectively). The genes GS, GR, and COPT1 modified their transcriptional levels depending on the metal and organ evaluated. These results provide evidence of specific defensive responses of this species against heavy metal stress, which is helpful to guide new research efforts and support the development of strategies for using Quillay for phytoremediation. Full article

Research on the effects of organic and inorganic Cu sources on metabolic processes and mechanisms in pigs is lacking. This study investigated the effects of different copper (Cu) sources and levels on hepatic Cu metabolism and transporter factors in growing pigs. Sixty healthy piglets (initial body weight 14.00 ± 0.30 kg) were randomly divided into four groups with five replicates of three pigs each. Four diets (AM, AH, BM, and BH) had different Cu sources [Cu sulphate (CuSO₄): A and Cu amino acids (Cu-AA): B] and levels [supplemented (120 mg/kg DM): M, supplemented (240 mg/kg DM): H]. The pre-feeding period was 7 days, followed by a 45-day feeding period. Slaughter and sample collection were carried out on the 46th day of the formal feeding period. Significant differences were considered at p < 0.05. The final weight and average daily gain (ADG) of growing pigs in the Cu-AA groups were significantly higher than those in the CuSO₄ groups. Serum Cu increased with increasing Cu supplementation on days 20 and 40. Cu concentrations in muscle, liver, and liver subcellular organelles were higher in Cu-AA groups. In the CuSO₄ groups, Cu concentrations were higher in kidneys and faeces. In Cu-AA groups, both the Cu concentrations in lysosomes and cytosol were higher, and the activities of cathepsin D (CTSD), β-glucosidase (BGL), and acid phosphatase (ACP) in lysosomes and cytoplasm were higher. Comparisons between groups showed that liver mRNA of copper transporter protein 1 (CTR1), ATPase copper-transporting beta (ATP7B), ceruloplasmin (CP), antioxidant protein 1 (ATOX1), and metallothionein (MT) was lower in the CuSO₄ group than in the Cu-AA group, with the best performance at 120 mg/kg Cu. mRNAs for ATPase copper-transporting alpha (ATP7A), cytochrome c oxidase copper chaperone 17 (COX17), and copper chaperone for superoxide dismutase (CCS) showed a decreasing trend in the Cu-AA groups. Cu-AA is better for Cu deposition, enhances the utilisation of Cu, reduces Cu excretion, and promotes the expression of relevant enzymes and transporters in the liver. Full article

It remains an open question whether violets use universal mechanisms, such as the production of metallothioneins, phytochelatins, and organic acids and/or rely on specific mechanisms like the production of antimicrobial cyclic peptides (cyclotides) for heavy metal tolerance. To contribute to the understanding of the role of cyclotides, we used seed-derived plants from metallicolous (M) and non-metallicolous (NM) populations of Viola tricolor, a pseudometallophyte tolerant to Zn and Pb. Eight- to ten-week-old plants were treated with 1000 μM of Zn or Pb for 3 or 7 days and subsequently measured for cyclotides and heavy metal content using MALDI-MS and Atomic Absorption Spectrometry (AAS), respectively. Individuals from the M population accumulated a similar amount of Zn but occasionally more Pb in comparison with the NM population. Of the 18 different cyclotides included in the analysis, some showed statistically significant changes under the heavy metal treatment. In general, a decrease was observed in the M population, whereas an increase was observed in the NM population (except for the 3-day treatment with Zn). The day of treatment and dose of metal and their interaction played a crucial role in the explained variance for cyclotides produced by the M individuals but not for the NM plants. This unravels the importance of this antimicrobial compound in heavy metal tolerance and indicates that, in V. tricolor, cyclotides are involved in heavy metal tolerance, but specimens from two populations have developed different strategies and tolerance mechanisms involving cyclotides to mitigate heavy metal stress. Full article