Search Results (1,119)

Background: Pharmacogenetic (PGx) testing could identify actionable drug–gene interactions, reducing the risks of inappropriate prescribing of certain medications in some patients. An area of growing public health concern is rising global rates of depression and antidepressant use over the last two decades. Prior research has elucidated perspectives of healthcare providers who prescribe antidepressants regarding the clinical utility of genetic information, including PGx testing, but there is a gap in understanding how individual perspectives and systemic contextual factors may combine to influence PGx testing adoption. Objective: The objective of this study was to elucidate combinations of individual and contextual conditions associated with willingness to adopt PGx testing for Cytochrome P450 Subfamily IID, Polypeptide 6 (CYP2D6) and Subfamily IIC, Polypeptide 19 (CYP2C19) among antidepressant prescribers. Methods: We conducted a cross-sectional, mixed-methods study using structured questionnaires and semi-structured interviews with healthcare providers who prescribe antidepressants within their scope of practice across four healthcare systems in the United States. We collected data on implementation science concepts from the Theoretical Domains Framework, the Consolidated Framework for Implementation Research (CFIR), and the Implementation Outcomes Framework. Coincidence analysis (CNA), a case-based, Boolean logic-based method that identifies minimally sufficient combinations of conditions that lead to a particular outcome, was used to identify combinations of conditions for PGx test adoption among antidepressant prescribers. Interviews were also conducted with 10 patients who received pharmacogenetic testing within these healthcare systems to contextualize findings with patient perspectives. Results: Prescribers adopted PGx testing when they believed it would be beneficial to patients and were not deterred by cost-related concerns; the combination of these conditions led to PGx adoption in the most highly supported CNA model. Patient perspectives were also consistent with the selected model, with data suggesting they may have greater willingness to tolerate costs when they perceived or experienced benefits from testing. Conclusions: Insights from this study may be used by health system administrators and public health policymakers to inform future PGx implementation strategies that enhance uptake and awareness of existing evidence for clinical benefits of PGx testing and mitigate cost-related barriers to adoption. Full article

To explore the opposing roles between the toxic acetaldehyde-producing enzyme Cytochrome P450-2E1 (CYP2E1) and acetaldehyde-clearing protein mitochondrial Aldehyde Dehydrogenase-2 (ALDH2) in alcohol-mediated cerebellar damage, two separate experiments were conducted. Young Svj/129 wild-type (WT) vs. Cyp2e1-Knockout (KO) mice were administered consecutive doses of 5 g/kg/dose ethanol (EtOH) at 12 h intervals, and C57BL/6J WT vs. Aldh2-KO mice were administered 4 g/kg/dose EtOH at 12 h intervals. Control mice were given dextrose, and cerebella were collected one hour after the last ethanol dose. Cerebellar tissue extracts were used for immunoblot analyses, and frozen tissue sections were evaluated by confocal microscopy with Fluoro-Jade C (FJC) staining for damaged neurons. Rotarod locomotor function of another mouse group was evaluated 48 h after ethanol exposure. Representative immunoblots showed increased levels of oxidative post-translational modifications (PTMs) (e.g., p-Ser/Thr-Pro, Ac-Lys, and acrolein adducts) in EtOH-exposed WT mice, and FJC-staining images revealed more degenerated neurons with decreased locomotor activity in ethanol-exposed WT compared to the corresponding Cyp2e1-KO mice. However, elevated levels of oxidative PTMs were observed in alcohol-exposed Aldh2-KO mice with increased damaged neurons stained with FJC. Our results show that CYP2E1 is a contributing factor, while ALDH2 shows a protective function, demonstrating their opposing roles in binge alcohol-mediated cerebellar degeneration. Full article

Wheat Fusarium head blight (FHB) is a globally prevalent and destructive fungal disease predominantly caused by Fusarium graminearum. Pydiflumetofen, a novel succinate dehydrogenase inhibitor (SDHI) fungicide, exhibits strong inhibitory activity against F. graminearum; however, the molecular regulatory mechanisms underlying the field-developed resistance in this pathogen remain poorly defined. In the present study, a field-evolved resistant isolate W24-039 and a sensitive isolate W24-016 were subjected to multi-omics analysis. The sequencing results identified compound mutations C89S/A93V in SdhC2, and A21T/S30F in SdhD of the resistant strain, which confer stable fungicide resistance without any detectable fitness costs. Physiological tests revealed that these target mutations sustain the homeostasis of succinate dehydrogenase (SDH) activity and intracellular ATP production. Following pydiflumetofen treatment, the sensitive isolate displayed remarkable declines in SDH activity, intracellular ATP content and deoxynivalenol (DON) biosynthesis, accompanied by markedly elevated cell membrane permeability. Transcriptomic sequencing uncovered 2221 differentially expressed genes (DEGs) in the sensitive strain under fungicide stress, and 2566 DEGs in the resistant isolate under the same conditions. The genes associated with detoxification and drug efflux, including cytochrome P450, glutathione S-transferase (GST), ABC and MFS transporters, were significantly upregulated in the resistant isolate. Metabolomic analysis indicated that differential metabolites were mainly enriched in the tricarboxylic acid (TCA) cycle, amino acid metabolism and membrane lipid biosynthesis pathways. The resistant strain maintained intact TCA cycle operation and accumulated high levels of pivotal metabolites such as phosphatidylcholine, unsaturated fatty acids and reduced glutathione. Integrated multi-omics analysis verified that the ABC transporter and glutathione metabolism pathways serve as core regulatory modules governing fungicide resistance. Collectively, F. graminearum develops resistance via the synergistic effects of SDH compound mutations, enhanced detoxification and efflux, and global metabolic remodeling, demonstrating that target-site mutation alone is not the sole driver of resistance, which is instead controlled by an intricate regulatory network involving multiple coordinated pathways. This study systematically characterizes the resistance regulatory network of F. graminearum against pydiflumetofen, and provides theoretical guidance for the rational application and sustainable field resistance management of this fungicide. Full article

Alcohol exposure during pregnancy leads to fetal alcohol spectrum disorders (FASD), yet the mechanisms through which alcohol disrupts the developing cerebrovasculature remain poorly defined. Acetaldehyde, the first oxidative metabolite of alcohol, can alter vascular function, but whether developing cerebral arteries possess intrinsic capacity to generate acetaldehyde is unknown. Alcohol is primarily oxidized by alcohol dehydrogenase (ADH), cytochrome P450 2E1 (CYP2E1), and catalase (CAT), and their local metabolic activity may contribute to cerebrovascular vulnerability. In this study, cerebral arteries were isolated from postnatal day (PND) 10 C57BL/6J mouse offspring (third trimester-equivalent to human pregnancy), and incubated ex vivo with physiologically relevant alcohol concentrations (13 or 50 mM). Acetaldehyde generation, transcript expression, protein abundance, and catalase-dependent metabolism were evaluated. Alcohol exposure produced a concentration-dependent increase in acetaldehyde generation within developing cerebral arteries, with comparable responses between males and females. Transcript analysis revealed that Adh1, Cyp2e1, and Cat were expressed across developing tissues; however, Western blotting showed that catalase was the only alcohol-metabolizing enzyme detectable at the protein level within developing cerebral arteries. Accordingly, catalase inhibition by sodium azide altered acetaldehyde production, revealing a significant blocker–sex interaction at the higher inhibitor concentration (0.06 mM). In summary, our ex vivo findings demonstrate that developing cerebral arteries possess intrinsic metabolic capacity to oxidize alcohol to acetaldehyde and that catalase plays an essential role in supporting this process at this developmental stage. These results point to a previously unrecognized metabolic pathway within the developing cerebrovasculature that may potentially contribute to early-life vulnerability to alcohol exposure. Full article

The red palm weevil, Rhynchophorus ferrugineus (Olivier), is among the most destructive invasive pests of date palms worldwide. In this study, mitochondrial cytochrome c oxidase subunit I (COI) and nuclear internal transcribed spacer (ITS) markers were analyzed in parallel to comparatively assess genetic diversity and haplotype variation in R. ferrugineus populations from Qassim Province, Saudi Arabia. Sequencing success rates reached 96.5% and 93.0% for COI and ITS, respectively. COI sequences exhibited very low nucleotide divergence among Qassim specimens (0.0–0.0077), indicating a highly conserved mitochondrial background and close phylogenetic similarity (p-distance = 0.0–0.0078) with an Egyptian reference haplotype (GU581319) and the reference R. ferrugineus mitochondrion (KT428893). In contrast, ITS analyses revealed substantially greater nuclear variation, identifying multiple haplotype groups with divergence levels of 10–19%. Haplotype diversity was higher in ITS (Hd = 0.876 ± 0.041) than in COI (Hd = 0.663 ± 0.068), while nucleotide diversity in ITS (π = 0.0387 ± 0.0013) was 36.9-fold greater than in COI (π = 0.00105 ± 0.00025; Z = 27.66, p < 0.001). Phylogenetic reconstruction showed greater population structuring in ITS than in COI. Integrated mitochondrial and nuclear markers improve genetic resolution and species identification in R. ferrugineus. Full article

Dociostaurus maroccanus is a major migratory pest first recorded in Xinjiang, China, in 2025 in the Ili River Valley and Tacheng City. This event represents a new situation of concern in the field of biological security along China’s northwestern border that warrants attention. This study investigated the genetic diversity and population structure of four populations from the China–Kazakhstan border region using combined mitochondrial cytochrome C oxidase subunit I (COI) and cytochrome B (Cytb) gene markers. A total of 41 haplotypes were identified from 74 individuals, with the shared haplotypes H3 and H6 being the most frequent. Haplotype network analysis revealed no clear geographic population structuring. Haplotype diversity was high (Hd = 0.957), whereas nucleotide diversity was low (π = 0.00212), indicating low overall genetic diversity. Frequent gene flow (Nm = 12.31–43.08) and minimal genetic differentiation (Fst = −0.0255 to 0.0199) were detected among populations. AMOVA indicated that genetic variation mainly occurred within populations (100.12%), with no significant differentiation among populations (−0.59%). Neutrality tests (Tajima’s D = −2.45136, p < 0.05; Fu’s Fs = −44.037, p < 0.001), the unimodal mismatch distribution, and goodness-of-fit test results for KZ1 population (SSD = 0.0028, p = 0.91; raggedness = 0.0225, p = 0.86), KZ2 population (SSD = 0.00846, p = 0.25; raggedness = 0.0650, p = 0.13) and YN population further support the expansion phenomenon. Mantel test (r = −0.5948, p = 0.9583) preliminarily indicated that population distribution was not correlated with geographic distance. Therefore, in the region covered by this study, the overall characteristics show recent population expansion features. The preliminary results of this study provide basic materials for understanding the genetic background of this species in China’s border regions and can serve as a reference for subsequent population dynamic monitoring and control work. Full article

The longissimus dorsi (LD) and biceps femoris (BF) muscles are important meat-producing regions in camels. Investigating differences in meat quality and proteomic profiles between the LD and BF muscles in Junggar Bactrian camels can provide a molecular basis for regulating camel meat quality and genetic improvement. In this study, 20 healthy adult male Junggar Bactrian camels were selected. Following slaughter, muscle samples were collected from the splenius (SP), triceps brachii (TB), LD, external oblique (EO), gluteus medius (GM), and BF. Meat quality parameters (pH, meat color, shear force, drip loss, and cooking loss) were measured. The LD exhibited the highest meat quality among the six cuts, in contrast to the BF, which showed the lowest. Proteomic analysis of LD and BF from 6 Junggar Bactrian camels was conducted to identify proteins associated with meat quality, yielding 81 differentially expressed proteins (DEPs). Gene Ontology (GO) enrichment analysis highlighted several significantly enriched terms among the DEPs (p < 0.05), including calcium-dependent phospholipid binding, zinc ion binding, and metal ion binding. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis (p < 0.05) further indicated notable enrichment in cytoskeletal organization, 2-oxocarboxylate metabolism, and the citric acid cycle. DEPs associated with meat quality were identified, including tubulin α-chain-like 3 and synaptic function regulator FMR1 isoform X15, which can serve as candidate DEPs for shear force. Protein phosphatase 1 regulatory subunit 14C isoform X1 can serve as a candidate differentially expressed protein for pH. Protein phosphatase 1 regulatory subunit 14C isoform X and anchoring protein repeat domain 1 can serve as candidate DEPs for cooking loss. Membrane-associated protein A4 and membrane-associated protein A7 isoform X1, as well as the transcriptional activator of cytochrome c oxidase 1, can serve as candidate DEPs for color a*. These data may serve as a reference for further studies on how different cuts affect meat quality and for practical efforts to improve camel meat quality. Full article

Metabolic dysfunction-associated steatohepatitis (MASH; formerly non-alcoholic steatohepatitis, NASH) is characterized by oxidative stress, inflammatory activation, hepatocellular injury, and progressive liver dysfunction. However, the global transcriptomic landscape underlying stress-induced hepatic injury remains incompletely understood. In this study, we employed a methionine–choline-deficient (MCD) diet-induced murine model to characterize the phenotypic and transcriptomic alterations associated with liver injury. Male C57BL/6J mice were fed either a control or MCD diet, and hepatotoxicity was assessed by survival analysis, body and liver weight measurements, serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, histopathological examination, RNA sequencing, quantitative real-time PCR (qRT-PCR), and tumor necrosis factor-alpha (TNF-α) enzyme-linked immunosorbent assay (ELISA). MCD feeding markedly reduced survival and body weight while inducing hepatomegaly and significant elevations in serum ALT and AST, indicating severe hepatocellular injury. Histopathological analysis demonstrated hepatic steatosis, hepatocellular ballooning, and lobular inflammation without histological evidence of fibrosis. Transcriptomic profiling revealed extensive gene expression remodeling, characterized by activation of inflammatory pathways, enrichment of MAPK-related signaling, dysregulation of lipid metabolism, suppression of antioxidant defense systems, impairment of cytochrome P450-mediated detoxification, and upregulation of apoptosis-associated genes. qRT-PCR further validated the differential expression of representative genes involved in inflammatory signaling (Tlr4, Nfkb1, Nlrp3, and Casp1), MAPK signaling (Fos), xenobiotic metabolism (Cyp4f18), lipid metabolism (Apoa4 and Lpl), extracellular matrix remodeling (Mmp12), and oxidative stress responses (Sod1 and Gstp1). In addition, elevated serum TNF-α levels provided protein-level evidence supporting activation of the TLR4/NF-κB/TNF-α/NLRP3 inflammatory axis. Although fibrosis-associated transcriptional responses were detected, the absence of histological fibrosis suggests transcriptional priming of fibrogenic pathways rather than established fibrogenesis. Collectively, these findings provide a transcriptomic framework linking oxidative stress, impaired detoxification, inflammatory activation, and stress-responsive signaling to MCD-induced hepatic injury. The MCD model provides a valuable experimental platform for characterizing hepatic stress-response transcriptomes and for generating hypotheses that can subsequently be evaluated in environmentally relevant toxicological models. Nevertheless, caution should be exercised when extrapolating these findings to obesity-associated human MASLD, as the MCD model lacks key metabolic features of the human disease, including obesity and insulin resistance. Therefore, the present findings should be interpreted primarily as transcriptomic signatures of stress-induced hepatic injury rather than as a direct representation of the pathophysiological processes underlying human obesity-associated MASLD. Full article

Despite increasing interest in fungal remediation systems for the treatment of persistent contaminants, the mechanisms governing fungal transformation of halogenated organic compounds remain poorly resolved. The aim of this study was to determine whether the transformation of halogenated nitrophenols is driven by isolated extracellular enzymes and cofactor-dependent oxidative activity or instead reflects coordinated system-level fungal metabolism. To address this question, we investigated the transformation of 2-chloro-4-nitrophenol (2C4NP) and 5-fluoro-2-nitrophenol (5F2NP) by ascomycete fungi Caldariomyces fumago (C. fumago) and Curvularia sp. under varying nutrient and cofactor conditions. Whole-culture transformation, crude supernatant activity, purified enzyme assays, intracellular detoxification responses, and genome-resolved functional annotation were integrated to evaluate the relative contributions of extracellular and intracellular processes. Transformation was strongly dependent on fungal species, substrate identity, nutrient availability, and cofactor composition. C. fumago achieved complete transformation of 2C4NP and up to 85.3% transformation of 5F2NP, whereas Curvularia sp. exhibited strict Na₃VO₄-dependent transformation of 5F2NP. Crude supernatants retained partial transformation capacity, achieving ~40–45% substrate depletion under conditions supporting whole-culture activity. Purified chloroperoxidase and laccase showed negligible independent activity and did not reproduce whole-culture transformation behavior. Lignin peroxidase activity was consistently induced during contaminant exposure and peaked during periods of maximum transformation. Cytochrome P450 inhibition did not prevent transformation. Baseline glutathione S-transferase activity was detected in both fungi, and comparative genome analysis identified conserved intracellular detoxification-associated enzyme alongside divergent extracellular oxidative enzyme repertoires. Together, these findings demonstrate that transformation of halogenated nitrophenols by fungi cannot be explained by isolated extracellular enzymes alone but is consistent with coordinated extracellular and intracellular system-level metabolism. These findings highlight an underexplored role for integrated fungal metabolic systems in bioremediation and provide a mechanistic basis for developing a scalable fungal platform for treatment of persistent halogenated contaminants. Full article

Since its first detection in 2010, Aedes albopictus has spread across northern Algeria, where vector control relies on the use of chemical insecticides. This study aimed to evaluate the susceptibility of Ae. albopictus populations from Algiers to commonly used larvicides and adulticides, as well as to characterize the underlying resistance mechanisms. Eggs were collected from three sites in Algiers. The susceptibility of larvae to temephos and Bacillus thuringiensis israelensis (Bti), as well as that of adults to permethrin, deltamethrin, malathion, and bendiocarb was evaluated using WHO bioassays. Genotyping of knockdown resistance (kdr) mutations was performed via PCR and sequencing. Metabolic resistance mechanisms were investigated using CDC bottle bioassays. The larvae were found to be susceptible to temephos and Bti. Bioassays on adults demonstrated susceptibility to deltamethrin, suspected resistance to permethrin, and resistance to malathion and bendiocarb. Genotyping revealed low frequencies of heterozygous kdr mutations (V1016G, I1532T, F1534C/S). Synergist assays highlighted the key role of esterases in malathion resistance, a minimal involvement of glutathione S-transferases and an unexpected antagonistic effect of cytochrome P450 monooxygenases. Although larvicides remain effective, resistance to organophosphates, carbamates, as well as suspected resistance to permethrin, has been detected. Esterase-mediated metabolic resistance and kdr mutations may contribute to this profile. These findings highlight the need for resistance monitoring and integrated vector control to ensure sustainable control of Ae. albopictus. Full article

Mitochondrial diseases have traditionally been viewed as energy deficiencies, but current evidence positions mitochondria as central regulators of multiple cell death pathways. This review systematically analyzes the molecular mechanisms of apoptosis and ferroptosis in the context of both primary mitochondrial diseases—caused by mutations in mtDNA or nuclear DNA directly affecting oxidative phosphorylation—and secondary mitochondrial dysfunction associated with broader pathological conditions. Apoptosis is an energy-dependent process characterized by mitochondrial outer membrane permeabilization, cytochrome c release, and caspase cascade activation, whereas ferroptosis involves iron-dependent lipid peroxidation, glutathione depletion, and inactivation of glutathione peroxidase 4 (GPX4), leading to accumulation of oxidized phospholipids predominantly in endoplasmic reticulum and plasma membranes; mitochondrial ultrastructural changes—including volume reduction and cristae loss—represent characteristic morphological features of ferroptosis rather than its primary site of initiation. Key findings reveal that reactive oxygen species overproduction, disruption of reducing equivalent metabolism, iron dyshomeostasis, and calcium overload simultaneously prime cells for both death pathways. Cytochrome c, p53, and BCL-2 family proteins serve as integration hubs, with cardiolipin peroxidation and phospholipid composition influencing pathway switching. Tissue specificity is pronounced in primary mitochondrial diseases: retinal ganglion cells in Leber’s hereditary optic neuropathy, cardiomyocytes in mtDNA-associated cardiomyopathies, and hepatocytes in mtDNA depletion syndromes exhibit distinct dominant death pathways. It should be noted, however, that for many conditions discussed, the evidence for ferroptosis involvement relies on indirect markers—such as lipid peroxidation products, decreased GPX4, and iron deposition—rather than on pharmacological rescue with ferrostatin-1 or liproxstatin-1 and rigorous exclusion of alternative death modalities; this limitation is discussed critically throughout the review. Diagnostic criteria combining morphological, biochemical, and pharmacological tools enable differentiation of death pathways. The review concludes that combined inhibition—using mitochondria-targeted antioxidants, GPX4 modulators, iron chelators, and mPTP blockers—together with personalized diagnostic algorithms offers the most promising therapeutic strategy. Understanding the apoptosis–ferroptosis crosstalk is essential for developing targeted interventions in mitochondrial diseases. Full article

Microplastic exposure is an emerging environmental risk factor for cardiovascular health; however, whether cardiovascular alterations can be detected after exposure cessation remains unclear. This study investigated subclinical cardiovascular alterations following repeated oral exposure to polystyrene microplastics (PSMPs), with particular emphasis on redox imbalance and mitochondrial function in delayed cardiovascular alterations. Male Sprague-Dawley rats were administered 0.5 μm PSMPs via oral gavage at varying dosages of 5 or 20 mg/kg every 5 days for 70 days, followed by a 35-day exposure-free period. Repeated exposure to PSMPs did not affect body or organ weights but altered cardiac serum biochemical markers. Cardiac tissue exhibited elevated NADPH oxidase 4 (NOX4) expression and decreased superoxide dismutase 1 (SOD1), SOD2, and catalase (CAT) activities, whereas malondialdehyde (MDA) levels remained unchanged, indicating a state of chronic, low-level oxidative stress. Mitochondrial respiratory chain activities, including nicotinamide adenine dinucleotide cytochrome c reductase (NCCR) and succinate cytochrome c reductase (SCCR), were significantly reduced. Ultrastructural analysis revealed mitochondrial swelling and cristae disruption. In parallel, mitochondrial biogenesis-related proteins, including peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α), nuclear respiratory factor 1 (NRF-1), and mitochondrial transcription factor A (TFAM), were downregulated, while mitophagy markers, including PTEN-induced kinase 1 (PINK1), Parkin RBR E3 ubiquitin protein ligase (Parkin), microtubule-associated protein 1 light chain 3 (LC3), and sequestosome 1 (p62), were upregulated. Notably, most significant alterations were primarily observed in the high-dose group. Furthermore, the aorta showed increased oxidative stress markers without overt structural remodeling. These findings suggest that repeated exposure to PSMP is associated with subclinical cardiac redox–mitochondrial dysregulation, potentially involving redox imbalance, impaired mitochondrial respiratory chain activity, reduced mitochondrial biogenesis, and altered mitochondrial quality-control markers. Full article

New copper(II) (C1) and palladium(II) (C2) complexes with S,O-tetradentate ligand (L) derived from thiosalicylic and thiopropionic acids were synthesized. In cell-based assays, (C1) exhibited the most pronounced activity within the tested compound series and was therefore advanced for mechanistic evaluation in 4T1 triple-negative breast cancer cells. (C1) significantly reduced 4T1 cell viability by inducing early and late apoptosis, accompanied by mitochondrial membrane depolarization and enhanced cytochrome C release. Consistently, (C1) increased the Bax/Bcl-2 ratio, promoting a pro-apoptotic shift. In parallel, (C1) triggered autophagy, as evidenced by decreased p62 and LC3B levels, induced G0/G1 cell-cycle arrest, and suppressed proliferative signaling by downregulating Ki67, cyclin D, and phosphorylated AKT. The DNA-binding studies showed moderate to strong affinity, favoring minor groove binding, with higher affinity for (C1) than for (C2). Tryptophan fluorescence quenching indicated a strong interaction with BSA via a predominantly static mechanism, more pronounced for (C1). Molecular docking at the DNA and BSA binding sites corroborated experimental findings and suggested favorable interactions between the complexes and apoptosis-related proteins (CASP3, BAX, and BCL2). The integrated experimental and computational data identify (C1) as a biologically active compound with multimodal biological effects in vitro, supporting further structural optimization and mechanistic investigation. Full article

Introduction: Temperature is a key environmental factor influencing the physiological and biochemical processes of aquatic organisms, including xenobiotic metabolism. Understanding how temperature modulates the toxicological effects of pollutants such as polycyclic aromatic hydrocarbons (PAHs) is crucial in the context of climate change. Among these compounds, benzo[a]pyrene (BaP) and benzo[a]anthracene (BaA) are priority pollutants in aquatic environments, resulting from incomplete combustion. Their relevance is attributed to persistence and metabolic bioactivation potential. Fish primary hepatocyte cultures represent a relevant in vitro model for studying combined effects of thermal stress and chemical exposures, while supporting the 3Rs principles (Replacement, Reduction, and Refinement). Objective: This study aims to assess temperature-dependent effects of BaP and BaA, and their mixtures in brown trout hepatocytes using cytochrome P450 1A (CYP1A) immunohistochemistry as an indicator of xenobiotic metabolism. Methodology: Primary hepatocytes were isolated using a two-step collagenase perfusion method and cultured in 24-well plates at 18 °C and 22 °C. Cells were exposed for 72 h to supplemented L-15 medium (control) or to 0.1% dimethyl sulfoxide in supplemented L-15 medium (solvent control), as well as to single exposures of 1 and 10 µM of BaP and BaA and to equimolar mixtures of both compounds (1 and 10 µM). Viability was assessed using the lactate dehydrogenase (LDH) assay. CYP1A immunostaining was quantified based on cytoplasmic staining intensity relative to background area. Results: No significant effects on cell viability were observed under any condition. Temperature significantly reduced CYP1A expression in single exposures at 22 °C compared to 18 °C. BaP induced a significant dose-dependent increase, while BaA differed from controls only at 10 µM. In mixtures, only treatment- and dose-dependent effects were observed, with no temperature influence detected. Conclusions: Overall, the data highlight temperature as a key modulator of biochemical responses to PAHs, with single and mixed exposures eliciting distinct effects and suggesting potential synergism in mixtures. Full article

Introduction: The temperature of rivers in the Iberian Peninsula has increased due to global warming. In addition, these rivers are polluted by contaminants of emerging concern, such as polycyclic aromatic hydrocarbons (PAHs). Higher temperatures and pollution concurrently impose threats to the Iberian Peninsula’s endemic species, including the brown trout (Salmo trutta), a cold-water species widely used in ecotoxicological studies. Because the liver is the main biotransformation organ, and is particularly sensitive to both chemical and temperature changes, in vitro liver models may represent valuable alternatives for assessing combined stressor effects, complying with the 3Rs principle. Objective: In line with the above, the present study aimed to evaluate the combined effects of a 4 °C temperature increase and the model PAH benzo[k]fluoranthene (B[k]F) on fish liver cells using a primary brown trout hepatocyte culture as a model. Methodology: Primary hepatocytes were seeded in 6-well plates at a density of 1.0 × 10⁶ cells/mL and exposed for 48 h to 1, 10, and 20 µM B[k]F at 18 °C (normothermia) and 22 °C (warming scenario). Cell viability was assessed using trypan blue, alamarBlue, and lactate dehydrogenase (LDH) assays. Cytochrome P450 (CYP)1A was evaluated in terms of its gene expression by RT-qPCR and its protein expression through immunocytochemistry (ICC). The immunostaining was quantified using a score system which considered five intensity staining levels. Results: Exposure to B[k]F and to the higher temperature increased LDH leakage without interaction effects. In contrast, the other viability assays did not show significant differences across conditions. Regarding CYP1A, both gene and protein expression increased with all B[k]F concentrations in relation to the controls, but were not influenced by temperature. Notably, the lowest B[k]F concentration (1 µM) elicited the highest CYP1A gene expression, suggesting a non-monotonic response. Conclusions: Overall, the model was responsive to both temperature (4 °C) increase and to B[k]F, validating its usefulness for assessing liver pollutant effects in the context of global warming. These findings support the application of fish primary hepatocyte models as relevant tools in ecotoxicology under environmentally realistic multi-stressor scenarios. Full article