Astilbin attenuates apoptosis induced by cadmium through oxidative stress in carp (Cyprinus carpio L.) head kidney lymphocyte

The alleviation of difenoconazole-induced kidney injury in common carp (Cyprinus carpio) by Silybin: involvement of inflammation, oxidative stress, and apoptosis

Triazole fungicides, such as difenoconazole (DFZ), are frequently used to control fungus in crops that pollute water. The common carp (Cyprinus carpio) (hereafter referred to as "carp") is an excellent bio-indicator of water quality. The seeds of the silymarin plant contain a flavonolignan called silybin (SYB), which is used to treat liver disease. To explore SYB's involvement in DFZ-triggered kidney damage in carps, an H&E assay was conducted, and ROS level was also examined. The results demonstrated that SYB alleviated DFZ-induced destruction of kidney tissue structure in carps, as well as alleviating the elevation of kidney ROS level in carps. RT-qPCR and Western blot were used to detect inflammation-, oxidative stress- and apoptosis-related factors at mRNA level and protein level. The experimental findings indicated that relative to the DFZ group, SYB+DFZ co-treatment reduced inflammation-related mRNA level of il-6, il-1β and tnf-α, elevated mRNA level of il-10. It also reduced protein expression levels of NF-κB and iNOS. In addition, SYB+DFZ co-treatment reduced DFZ-induced increase in the oxidative stress-related mRNA indicators sod and cat, and decreased the protein expression levels of Nrf2 and NQO1. SYB reduced the DFZ-induced increase in pro-apoptotic gene Bax mRNA and protein expression levels and the DFZ-induced decrease in anti-apoptotic gene Bcl-2 mRNA and protein expression levels. In summary, SYB potentially mitigates DFZ-induced kidney damage in carp by addressing inflammation, oxidative stress, and apoptosis. Our results establish a theoretical foundation for the clinical advancement of freshwater carp feeds.

BDE-47-induced damage prevented by melatonin in grass carp hepatocytes (L8824)

Polybrominated diphenyl ethers (PBDEs) are toxic to organisms with melatonin (MT) providing protection for tissues and cells against these. This study investigates the mechanism of damage of 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) and the cellular protection of MT on grass carp hepatocytes. Grass carp hepatocytes were exposed to 25 μmol/L BDE-47 and/or 40 μmol/L MT for 24 h before testing. Acridine orange/ethidium bromide (AO/EB) double fluorescence staining results showed that BDE-47 could induce cell apoptosis. The expression levels of the endoplasmic reticulum (ER) stress-related genes ire1, atf4, grp78, perk, and chop were also significantly up-regulated (P < 0.01). The levels of the apoptosis-related genes caspase3, bax, and caspase9 were significantly up-regulated (P < 0.0001), while the level of bcl-2 was significantly down-regulated (P < 0.01). Compared with the BDE-47 group, the BDE-47 + MT group showed reduced levels of ER and apoptosis of hepatocytes, while the expression of the ER stress-related genes ire1, atf4, grp78, perk, and chop and the apoptosis-related genes caspase3, bax, and caspase9 were down-regulated (P < 0.05), and the level of bcl-2 was up-regulated (P < 0.01). In conclusion, BDE-47 can activate ER and apoptosis in grass carp hepatocytes, while MT can reduce these responses.

Environmental Chemical-Induced Reactive Oxygen Species Generation and Immunotoxicity: A Comprehensive Review

Significance: Reactive oxygen species (ROS), the reactive oxygen-carrying chemicals moieties, act as pleiotropic signal transducers to maintain various biological processes/functions, including immune response. Increased ROS production leads to oxidative stress, which is implicated in xenobiotic-induced adverse effects. Understanding the immunoregulatory mechanisms and immunotoxicity is of interest to developing therapeutics against xenobiotic insults. Recent Advances: While developmental studies have established the essential roles of ROS in the establishment and proper functioning of the immune system, toxicological studies have demonstrated high ROS generation as one of the potential mechanisms of immunotoxicity induced by environmental chemicals, including heavy metals, pesticides, aromatic hydrocarbons (benzene and derivatives), plastics, and nanoparticles. Mitochondrial electron transport and various signaling components, including NADH oxidase, toll-like receptors (TLRs), NF-κB, JNK, NRF2, p53, and STAT3, are involved in xenobiotic-induced ROS generation and immunotoxicity. Critical Issues: With many studies demonstrating the role of ROS and oxidative stress in xenobiotic-induced immunotoxicity, rigorous and orthogonal approaches are needed to achieve in-depth and precise understanding. The association of xenobiotic-induced immunotoxicity with disease susceptibility and progression needs more data acquisition. Furthermore, the general methodology needs to be possibly replaced with high-throughput precise techniques. Future Directions: The progression of xenobiotic-induced immunotoxicity into disease manifestation is not well documented. Immunotoxicological studies about the combination of xenobiotics, age-related sensitivity, and their involvement in human disease incidence and pathogenesis are warranted. Antioxid. Redox Signal. 40, 691-714.

Polystyrene microplastics mediate cell cycle arrest, apoptosis, and autophagy in the G2/M phase through ROS in grass carp kidney cells

Microplastics (MPs) have attracted widespread worldwide attention as a new pollutant. However, the role of reactive oxygen species (ROS) and cell cycle in nephrotoxicity induced by different concentrations of polystyrene microplastics (PS-MPs) is unknown. This study used grass carp kidney cells (CIK) treated with different concentrations of PS-MPs (0, 0.012, 0.0625, and 0.5 mg L-1 ) as subjects. With the increase of PS-MPs concentration, the levels of ROS and malonaldehyde increased, while the level of total antioxidant capacity, superoxide Dismutase (SOD), and glutathione (GSH) activity decreased. The expression of BUB1 mitotic checkpoint serine/threonine kinase (BUB1), cyclin-dependent kinase (CDK1), CDK2, CyclinB1, cell division cycle 20 homolog (CDC20), and B-cell lymphoma-2, sequestosome 1 decreased significantly. Nevertheless, the expression of Caspase 3, Cleave-Caspase 3, cytochrome c (Cytc), BCL2-associated X, apoptosis regulator, poly ADP-ribose polymerase (PARP), Cleave-PARP, Caspase 9, autophagy immunoblot kit (LC3), and Beclin1 increased. Our research shows that PS-MPs can trigger oxidative stress and induce cell cycle arrest, apoptosis, and autophagy in CIK cells by regulating ROS. This work provides a theoretical basis for cellular biology and toxicology mechanisms and new insights into the potential risks to animals from MPs exposure in the environment.

Selenomethionine alleviates decabromodiphenyl ether-induced oxidative stress and ferroptosis via the NRF2/GPX4 pathway in the chicken brain

Decabromodiphenyl ether (BDE209) is a toxic environmental pollutant that can cause neurotoxicity, behavioral abnormalities, and cognitive impairment in animals. However, the specific mechanisms of BDE209-induced neurological injury and effective preventative and therapeutic interventions are lacking. Even though selenomethionine (Se-Met) has a significant detoxification effect and protects the nervous system, it remains unclear whether Se-Met can counteract the toxic effects of BDE209. For the in vivo test, we randomly divided 60 1-week-old hy-line white variety chicks into the Con, BDE209, Se-Met, and BDE209 +Se-Met groups. In vitro experiments were performed, exposing chick embryo brain neurons to BDE209, Se-Met, N-Acetylcysteine (NAC, a ROS inhibitor), and RSL3 (a GPX4 inhibitor). We demonstrated that BDE209 induced oxidative stress and ferroptosis in the chicken brain, which mainly manifested as mitochondrial atrophy, cristae breakage, increased Fe2+ and MDA content, decreased antioxidant enzyme activity, and the inhibition of the NRF2/GPX4 signaling pathway in the brain neurons. However, Se-Met supplementation reversed these changes by activating the NRF2/GPX4 pathway, reducing mitochondrial damage, enhancing antioxidant enzyme activity, and alleviating ferroptosis. This study provides insight into the mechanism of BDE209-related neurotoxicity and suggests Se-Met as an effective preventative and control measure against BDE209 poisoning.

Exploring the synergistic interplay of sulfur metabolism and electron transfer in Cr(VI) and Cd(II) removal by Clostridium thiosulfatireducens: Genomic and mechanistic insights

In this study, a sulfate-reducing bacterium, Clostridium thiosulfatireducens (CT) was reported and the performance and removal mechanism of Cr(VI) and Cd(II) removal were investigated. It is noteworthy that the dsrAB gene is absent in this strain, but the strain is capable of producing sulfide. The conversion rate of Cr(VI) by CT was 84.24 % at a concentration of 25 mg/L, and the conversion rate of Cd(II) was 94.19 % at a concentration of 28 mg/L. The complete genome is 6,106,624 bp and the genome consisted of a single chromosome. The GC content of the chromosomes was 29.65 %. The mechanism of heavy metal removal by CT bacteria mainly includes biosorption, electron transfer and redox, with reduction combined with S2- precipitation as the main pathway. The product characterization results showed that the formation of mainly ionic crystals and precipitates (CdS, Cd(OH)2, Cr(OH)3, Cr2O3) after adsorption. Genome-wide techniques have shown that the clearance of Cr(VI) and Cd(II) by CT is largely dependent on sulfate transport, sulfur metabolism, and energy metabolism to some extent. In addition, genes related to ATP binding, electron carrier activity, transporter protein genes, and DNA repair are also important factors to improve the heavy metal resistance and transformation ability of CT strains. Both the Fe-S cycle and the ROS-resistant system can enhance the electron transfer activity and thus slow down the damage of heavy metals to microorganisms. This study fills the gap in the understanding of the basic properties and heavy metal transformation mechanism of CT.

Quercetin alleviates the toxicity of difenoconazole to the respiratory system of carp by reducing ROS accumulation and maintaining mitochondrial dynamic balance

Difenoconazole (DFZ) is a fungicidal pesticide extensively employed for the management of fungal diseases in fruits, vegetables, and cereal crops. However, its potential environmental impact cannot be ignored, as DFZ accumulation is able to lead to aquatic environment pollution and harm to non-target organisms. Quercetin (QUE), a flavonoid abundant in fruits and vegetables, possesses antioxidant and anti-inflammatory properties. In this article, carp were exposed to 400 mg/kg QUE and/or 0.3906 mg/L DFZ for 30 d to investigate the effect of QUE on DFZ-induced respiratory toxicity in carp. Research shows that DFZ exposure increases reactive oxygen species (ROS) production in the carp's respiratory system, leading to oxidative stress, inflammation, and damage to gill tissue and tight junction proteins. Further research demonstrates that DFZ induces mitochondrial dynamic imbalance and gill cell apoptosis. Notably, QUE treatment significantly reduces ROS levels, alleviates oxidative stress and inflammation, and mitigates mitochondrial dynamics imbalance and mitochondrial apoptosis. This study emphasizes the profound mechanism of DFZ toxicity to the respiratory system of common carp and the beneficial role of QUE in mitigating DFZ toxicity. These findings contribute to a better understanding of pesticide risk assessment in aquatic systems and provide new insights into strategies to reduce their toxicity.

Astilbin antagonizes developmental cardiotoxicity after cadmium exposure in chicken embryos by inhibiting endoplasmic reticulum stress and maintaining calcium homeostasis

Cadmium (Cd) is a dangerous heavy metal with high toxicity that is known to impair development. Astilbin (ASB) is a protective flavonoid compound. We aimed to explore whether ASB can antagonize the myocardial developmental toxicity of Cd exposure. Cd (2 µg) and/or ASB (0.002 µg) were injected into embryonized eggs that were 1 day old. Histological examinations revealed Cd-induced ventricular dilation, reduced wall thickness, and disrupted myocardial fiber connections, while co-administration of ASB mitigated these effects. Electron microscopy confirmed ASB's ability to counteract Cd-induced myocardial cell myofibril damage. Real-time quantitative PCR (QRT-PCR) and western blot (WB) molecular investigations revealed that Cd increased endoplasmic reticulum stress in myocardial tissue and primary cardiomyocytes, as shown by raised expression of stress-related genes (GRP78, XBP1, GRP94, ATF4, ATF6, IRE1, and CHOP). Moreover, Cd disrupted calcium homeostasis, affecting important genes linked to Ca2+ channels and causing an excess of Ca2+ in the cytoplasm. In addition, we detected genes related to development and differentiation-related genes in myocardial tissue and primary cardiomyocytes. The results showed that the downregulation of transcription factors in the IrxA cluster, Mefs, and Tbxs families after Cd exposure indicated that cardiac transcription was hindered and cardiac markers (TnnT2, TnnC1, Gata4, Gata6, and Nkx2-5) were abnormally expressed. ASB successfully mitigated these disturbances. During the cell cycle, primary cardiomyocytes undergo growth arrest in flow cytometry. These results suggest that the maturation and differentiation of cardiomyocytes are inhibited after Cd exposure, and ASB has an antagonistic effect on Cd. The present study indicated that Cd could trigger developmental cardiotoxicity in chicken embryos and primary cardiomyocytes by endoplasmic reticulum stress and Ca2+ overload, respectively, while ASB has an antagonistic effect.

Ecotoxicology applied to conservation: Potential negative metal and metalloid contamination effects on the homeostatic balance of the critically endangered Brazilian guitarfish, Pseudobatos horkelii (Elasmobranchii: Rhinobatidae)

Metal contamination poses a significant threat to elasmobranchs, underscoring the need for targeted conservation approaches. The critically endangered Brazilian guitarfish, Pseudobatos horkelii, confronts an array of challenges, notably overexploitation, putting its survival at risk. Our study investigated the potential toxicity arising from arsenic (As), cadmium (Cd), mercury (Hg), and lead (Pb) contamination across various adult guitarfish tissues from southeastern Brazil. Serological stress indicators, nutritional metabolites, and creatinine, an organ function marker, were also assessed, and Selenium (Se) levels were also investigated for possible protective effects. Our investigation unveiled significant correlations between metal concentrations and the determined physiological markers, shedding light on potential adverse effects. Remarkably, six correlations were indicative of how Hg and Pb negatively impact hepatic metabolite assimilation, while As was shown to influence renal phosphorus dynamics, Cd to affect rectal gland phosphorus regulation, and Pb to influence creatinine production in muscle tissue. Furthermore, Se demonstrated protective properties against Cd, Hg, and Pb, suggesting a role in alleviating the toxicity of these elements. Despite probable protective Se influences, the detected elemental interactions still suggest potential for organ impairment. These findings gain heightened significance within the context of the cumulative stressors faced by the Brazilian guitarfish, with metal contamination exhibiting the capacity to erode this species resilience against both anthropogenic and environmental pressures, thereby disrupting systemic equilibrium and jeopardizing wild populations. By investigating the intricate balance between metal accumulation and physiological consequences, our study contributes with crucial insights into potential conservation strategy formulations towards pollution for this critically endangered elasmobranch species.

Deciphering the Role of Selenoprotein M

Selenocysteine (Sec), the 21st amino acid, is structurally similar to cysteine but with a sulfur to selenium replacement. This single change retains many of the chemical properties of cysteine but often with enhanced catalytic and redox activity. Incorporation of Sec into proteins is unique, requiring additional translation factors and multiple steps to insert Sec at stop (UGA) codons. These Sec-containing proteins (selenoproteins) are found in all three domains of life where they often are involved in cellular homeostasis (e.g., reducing reactive oxygen species). The essential role of selenoproteins in humans requires us to maintain appropriate levels of selenium, the precursor for Sec, in our diet. Too much selenium is also problematic due to its toxic effects. Deciphering the role of Sec in selenoproteins is challenging for many reasons, one of which is due to their complicated biosynthesis pathway. However, clever strategies are surfacing to overcome this and facilitate production of selenoproteins. Here, we focus on one of the 25 human selenoproteins, selenoprotein M (SELENOM), which has wide-spread expression throughout our tissues. Its thioredoxin motif suggests oxidoreductase function; however, its mechanism and functional role(s) are still being uncovered. Furthermore, the connection of both high and low expression levels of SELENOM to separate diseases emphasizes the medical application for studying the role of Sec in this protein. In this review, we aim to decipher the role of SELENOM through detailing and connecting current evidence. With multiple proposed functions in diverse tissues, continued research is still necessary to fully unveil the role of SELENOM.

Astilbin targeted Sirt1 to inhibit acetylation of Nrf2 to alleviate grass carp hepatocyte apoptosis caused by PCB126-induced mitochondrial kinetic and metabolism dysfunctions

3, 3', 4, 4', 5-pentachlorobiphenyl (PCB126) is extensively utilized in electronic products, lubricant, and insecticide due to its excellent chemical stability and insulation prosperity, resulting in its frequent detection in environment. In addition, atmospheric deposition, as well as industrial and urban wastewater discharge can also lead to PCB126 contamination in marine environment, triggering damages to the tissues of aquatic organisms through oxidative stress. Astilbin is a type of flavonoid compound found in plants that plays a crucial role in providing powerful antioxidant and anti-inflammatory properties. In this study, we aimed to investigate the specific mechanism of PCB126-induced damage and the potential protective effect of Astilbin. To achieve this, we treated grass carp hepatocytes (L8824) with 75 μM PCB126 and/or 0.5 mM Astilbin for 24 h and used experimental methods such as Flow cytometry, molecular docking, PPI analysis, detection of commercial kits (ATP concentration and ATPnase activity) and measurement of mitochondrial membrane potential (ΔΨm). Our findings revealed that PCB126 exposure resulted in a decrease in expression levels of Sirt1, factors related to mitochondrial fusion (Opa1, Mfn1, and Mfn2), antioxidant (CAT, SOD1, and SOD2), energy metabolism (PKM2, IDH, and SDH) and anti-apoptosis (Bcl-2), and an increase in expression levels of Nrf2 acetylation, mitochondrial fission (Drp1), factors that promote apoptosis (Cytc, Bax, Cas9, and Cas3) in L8824 cells. Furthermore, our findings revealed a decrease in ΔΨm, ATP concentration and ATPnase activity and apoptosis levels in L8824 cells. Noteworthy, treatment with Astilbin reversed these results. Molecular docking provides solid evidence for the interaction between Astilbin and Sirt1. In summary, our findings suggested that Astilbin promoted the deacetylation of Nrf2 by interacting with Sirt1, thereby alleviating PCB126-induced mitochondrial apoptosis mediated by mitochondrial dynamics imbalance and energy metabolism disorder through the inhibition of oxidative stress in L8824 cells. Our research has initially revealed the correlation between acetylation and apoptosis induced by PCB126, which provided a foundation for a better comprehension of PCB126 toxicity. Additionally, it expanded the potential application value of Astilbin.

New insights into Microalgal astaxanthin's effect on Lambda-cyhalothrin-induced lymphocytes immunotoxicity in Cyprinus carpio: Involving miRNA-194-5p-FoxO1-mediated-mitophagy and pyroptosis

Lambda-cyhalothrin (LC), a pyrethroid insecticide widely used in agriculture, causes immunotoxicity to aquatic organisms in the aquatic environment. Microalgal astaxanthin (MA) is a natural carotenoid that enhances viability of a variety of fish. To investigate the immunotoxicity of LC and the improvement effect of MA in lymphocytes (Cyprinus carpio), lymphocytes were treated with LC (80 M) and/or MA (50 M) for 24 h. Firstly, CCK8 combined with PI staining results showed that MA significantly attenuated the LC-induced lymphocyte death rate. Secondly, LC exposure resulted in excessively damaged mitochondrial and mtROS, diminished mitochondrial membrane potential and ATP content, which could be improved by MA. Thirdly, MA upregulated the levels of mitophagy-related regulatory factors (Beclin1, LC3, ATG5, Tom20 and Lamp2) induced by LC. Importantly, MA decreased the levels of pyroptosis-related genes treated with LC, including NLRP3, Cas-4, GSDMD and active Cas-1. Further study indicated that LC treatment caused excessive miRNA-194-5p and reduced levels of FoxO1, PINK1 and Parkin, which was inhibited by MA treatment. Overall, we concluded that MA could enhance damaged mitochondrial elimination by promoting the miRNA-194-5p-FoxO1-PINK1/Parkin-mitophagy in lymphocytes, which reduced mtROS accumulation and alleviated pyroptosis. It offers insights into the importance of MA application in aquaculture as well as the defense of farmed fish against agrobiological hazards in fish under LC.

Soybean glycinin and β-conglycinin damage the intestinal barrier by triggering oxidative stress and inflammatory response in weaned piglets

PURPOSE

Soybean glycinin (11S) and β-conglycinin (7S) are major antigenic proteins in soybean and can induce a variety of allergic reactions in the young animals. This study aimed to investigate the effect of 7S and 11S allergens on the intestine of piglets.

METHODS

Thirty healthy 21-day-old weaned "Duroc × Long White × Yorkshire" piglets were randomly divided into three groups fed with the basic diet, the 7S supplemented basic diet, or the 11S supplemented basic diet for 1 week. Allergy markers, intestinal permeability, oxidative stress, and inflammatory reactions were detected, and we observed different sections of intestinal tissue. The expressions of genes and proteins related to NOD-like receptor thermal protein domain associated protein 3 (NLRP-3) signaling pathway were detected by IHC, RT-qPCR, and WB.

RESULTS

Severe diarrhea and decreased growth rate were observed in the 7S and 11S groups. Typical allergy markers include IgE production and significant elevations of histamine and 5-hydroxytryptamine (5-HT). More aggressive intestinal inflammation and barrier dysfunction were observed in the experimental weaned piglets. In addition, 7S and 11S supplementation increased the levels of 8-hydroxy-2 deoxyguanosine (8-OHdG) and nitrotyrosine, triggering oxidative stress. Furthermore, higher expression levels of NLRP-3 inflammasome ASC, caspase-1, IL-1β, and IL-18 were observed in the duodenum, jejunum, and ileum.

CONCLUSION

We confirmed that 7S and 11S damaged the intestinal barrier of weaned piglets and may be associated with the onset of oxidative stress and inflammatory response. However, the molecular mechanism underlying these reactions deserves further study.

Txnrd3 knockout enhancement of lung injury induced by Ni exposure via the VEGF-VEGFR-2 axis and alleviation of this effect by melatonin

Ni exposure leads to respiratory diseases in mice. Txnrd3 has been shown to have a protective effect on the body, but there is a paucity of empirical research focusing specifically on lung tissue. Melatonin possesses potent antioxidant, anti-inflammatory, and anti-fibrotic effects. By regulating inflammation-related factors, melatonin can activate the VEGF signaling pathway, ultimately alleviating lung injuries caused by Ni exposure. One hundred and sixty 8-week-old C57BL/6N mice, that were wild-type or Txnrd3-/- mice and 25-30 g in weight, were randomly divided into eight groups, including the NC group, Ni group, melatonin-treated group, and Ni plus melatonin group. Ni (10 mg/kg) was gavaged, and melatonin (2 mg/kg) was administered for 21 days. Inflammatory cells were found in the bronchioles of Txnrd3-/- mice under Ni exposure. Ultrastructural examination revealed that the homozygous-Ni group had a high amount of collagen fibers. The antioxidant capacity studies also revealed that mice lungs underwent oxidative stress. The results of qRT-PCR and WB showed that Ni induced an inflammatory response, which was also aggravated in Txnrd3-/- mice. Melatonin can effectively reduce the above symptoms. In conclusion, Ni causes lung injury by activating the VEGF-VEGFR-2 pathway and Txnrd3 knockout aggravates injury after Ni exposure.

Micro-algal astaxanthin improves lambda-cyhalothrin-induced necroptosis and inflammatory responses via the ROS-mediated NF-κB signaling in lymphocytes of carp (Cyprinus carpio L.)

Lambda-cyhalothrin (LCY) is a widely used toxic pesticide that causes harmful effects on the immune organs of fish and aquatic species. Micro-algal astaxanthin (MAA), a heme pigment found in haematococcus pluvialis, has been shown to benefit antioxidants and immunity in aquaculture. To investigate how MAA protects carp lymphocytes from LCY-induced immunotoxicity, a model of fish lymphocytes treated with LCY and/or MAA was established. Lymphocytes from carp (Cyprinus carpio L.) were given LCY (80 μM) and/or MAA (50 μM) as a treatment for a period of 24 h. Firstly, LCY exposure resulted in excessive ROS and malondialdehyde production and reduces antioxidant enzymes (SOD and CAT), indicating a reduced capacity of the antioxidant system. Secondly, the results of flow cytometry and AO/EB labeling proved that lymphocytes treated with LCY have a larger ratio of necroptosis. In addition, LCY upregulated the levels of necroptosis-related regulatory factors (RIP1, RIP3 and MLKL) via the ROS-mediated NF-κB signaling pathway in lymphocytes. Thirdly, LCY treatment caused increased secretion of inflammatory genes (IL-6, INF-γ, IL-4, IL-1β and TNF-α), leading to immune dysfunction in lymphocytes. Surprisingly, LCY-induced immunotoxicity was inhibited by MAA treatment, indicating that it effectively attenuated the LCY-induced changes described above. Overall, we concluded that MAA treatment could ameliorate LCY-induced necroptosis and immune dysfunction by inhibiting the ROS-mediated NF-κB signaling in lymphocytes. It provides insights into the protection of farmed fish from agrobiological threats in fish under LCY and the value of MAA applications in aquaculture.

Effects of cadmium chloride and biofertilizer (Bacilar) on biochemical parameters of freshwater fish, Alburnus mossulensis

Fish in wild are often faced with various types of xenobiotics, that may display synergistic or antagonistic effects. In this study, we aim to examine how exposure to agrochemical compound (Bacilar) and cadmium (CdCl₂) alone and in combination affect biochemical parameters (lactate dehydrogenase, aspartate aminotransferase, alkaline phosphatase, gamma-glutamyl transferase, alanine aminotransferase; creatine phosphokinase (CKP), cholinesterase) and oxidative stress (total antioxidant capacity, catalase, malondialdehyde and protein carbonyl concentrations) of freshwater fish Alburnus mossulensis. Fish were exposed to two concentrations of Bacilar (0.3, and 0.6 mL L^-1) and to 1 mg L^-1 cadmium chloride alone and in combination for 21 days. Results showed that fish accumulate Cd in their body, with the highest rate in individuals exposed to Cd in combination with Bacilar. Both xenobiotics in fish liver induced the activation of liver enzymes suggesting hepatotoxic effects, with the greatest impact in co-exposed groups. A significant decrease in the hepatocyte's total antioxidant capacity indicates the collapse of the antioxidant defense in fish exposed to Cd and Bacilar. A decrease in the antioxidant biomarkers was followed by increased oxidative damage of lipids and proteins. We also reported altered function in the muscle of individuals exposed to Bacilar and Cd seen as decreased activities in CKP and butyrylcholinesterase. Overall, our results point to the toxicity of both Bacilar and Cd on fish but also to their synergistic effects on Cd bioaccumulation, oxidative stress, and liver and muscle damage. This study highlights the need for evaluating the use of agrochemicals and their possible additive effects on non-target organisms.

Cadmium induced time-dependent kidney injury in common carp via mitochondrial pathway: Impaired mitochondrial energy metabolism and mitochondrion-dependent apoptosis

Toxic effect of heavy metal cadmium (Cd) on fish kidneys had been reported. Mitochondrion is an important organelle for maintaining kidney function, while its role in Cd-induced kidney injury in common carp remained unclarified. In this experiment, we established a poisoning model of common carp with Cd exposure (0.26 mg/L) for 15, 30, and 45 days. Serum biochemistry determination, histological observation, TUNEL assay, qRT-PCR, Western blot, and integrated biomarker response (IBR) were applied to assess the nephrotoxicity of Cd to common carp. Our results displayed that Cd exposure increased the levels of serum biochemical indexes (UREA, CRE, and UA), indicating kidney injury. We further revealed via histological observation that Cd damaged structural integrity of kidneys, as evidenced by renal glomerulus and renal tubular injury, hallmark phenotypes of apoptosis, and mitochondrial damage, suggesting that mitochondria damage and apoptosis were involved in Cd-induced kidney injury. Moreover, Cd exposure decreased ATPase (Na⁺/K⁺-ATPase, Ca²⁺-ATPase, Mg²⁺-ATPase, and Ca²⁺Mg²⁺-ATPase) activities as well as PGC-1a and Mfn2 levels, while increased Drp1 and PINK1 levels as well as LC3-II/LC3-I ratio, which indicated that Cd-impaired renal energy metabolism was related to mitochondrial dysfunction. Additionally, we found that Cd induced oxidative stress (abnormal levels of SOD, CAT, GPX, MDA, and H₂O₂) in kidneys, which was involved in triggering mitochondrial dysfunction and further impairing mitochondrial energy metabolism. Moreover, the occurrence of mitochondria-dependent apoptosis was found after Cd-exposure in common carp kidneys, as indicated by enhanced levels of Bax, CytC, APAF1, Caspase-9, and Caspase-3, while declined level of Bcl-2. Subsequently, we confirmed a time-dependent nephrotoxicity of Cd to common carp via IBR assessment. In conclusion, Cd induced time-dependent nephrotoxicity in common carp via mitochondrial pathway. This mitochondria-oriented study shed light on underlying mechanisms of Cd-induced renal pathologies and provided a theoretical basis for evaluating Cd toxicity to aquatic organisms.

The effect of acute toxicity from tributyltin on Liza haematocheila liver: Energy metabolic disturbance, oxidative stress, and apoptosis

Tributyltin (TBT), a highly toxic and persistent organic pollutant, is widely distributed in coastal waters. Liza haematocheila (L. haematocheila) is one of bony fish distributing coincident with TBT, and exposure risk of TBT to this fish is unknown. In this study, L. haematocheila was exposed to TBT of 0, 3.4, 6.8, and 17.2 μg/L for 48 h to explore hepatic response mechanism. Our results showed that Sn content in livers increased after 48 h of exposure. HSI and histological changes indicated that TBT suppressed liver development of L. haematocheila. TBT reduced ATPase activities. The increased RB in blood and the reduced TBC were measured after exposure to TBT. T-AOC and antioxidant enzymes SOD, CAT, and GPx activities were inhibited while MDA content was increased. Liver cells showed apoptosis characteristics after TBT exposure. Furthermore, transcriptome analysis of livers was performed and the results showed energy metabolism-related GO term (such as ATPase complex and ATPase dependent transmembrance transport complex), oxidative stress-related GO term (such as Celllular response to oxidative stress and Antioxidant activity), and apoptosis-related GO term (such as Regulation of cysteine-type endopeptidase activity involved in apoptosic signaling pathway). Moreover, we found six energy metabolism-related differentially expressed genes (DEGs) including three up-regulated DEGs (atnb233, cftr, and prkag2) and three down-regulated DEGs (acss1, abcd2, and smarcb1); five oxidative stress-related DEGs including one up-regulated DEG (mmp9) and four down-regulated DEG (prdx5, hsp90, hsp98, and gstf9); as well as six apoptosis-related DEGs including five up-regulated DEGs (casp8, cyc, apaf1, hccs, and dapk3) and one down-regulated DEG (bcl2l1). Our transcriptome data above further confirmed that acute stress of TBT led energy metabolic disturbance, oxidative stress, and apoptosis in L. haematocheila livers.

Induction of autophagy via the ROS-dependent AMPK/mTOR pathway protects deoxynivalenol exposure grass carp hepatocytes damage

Deoxynivalenol (DON) is one of the most frequently found mycotoxin sources in feed and raw food products, endangering human and animal health. The mechanism of grass carp (Ctenopharyngodon idellus) liver cell (L8824) toxicity induced by DON is still unknown. The DON was administered to the L8824 cells in concentrations of 150, 200, and 250 ng/mL for 24 h. The results of this study suggested that DON could enable L8824 cells to significantly increase the levels of autophagy. Concurrently, DON could trigger autophagy through the AMPK-mTOR pathway, which upregulated the expression of p-AMPK and p-ULK1 while downregulating the expression of p-mTOR. In the meantime, DON treatment could alter the levels of expression of the related proteins in autophagy. Additionally, DON treatment dramatically reduced the activity of the antioxidant enzymes as well as increased the levels of oxidase, which increased the production of ROS in L8824 cells. This indicates that DON could induce oxidative stress. Furthermore, we discovered that DON exposure caused apoptosis, which is characterized by elevated levels of BAX, Caspase 9, Caspase 3, and decreased Bcl-2 levels. Next, it was investigated how oxidative stress affected DON-induced autophagy. The research revealed that the oxidative stress inhibitor (NAC) attenuated DON-induced autophagy. Additionally, the study also investigated how autophagy worked under the L8824 cells induced by DON. The ROS production, however, was enhanced by the addition of the autophagy inhibitor (3-MA). Additionally, co-treatment with the apoptosis inhibitor Z-VAD-FMK had no influence on autophagy. The combined findings showed that induction of autophagy via the ROS-dependent AMPK-mTOR pathway protects DON-induced L8824 cells from damage.

Bioimmobilization and transformation of chromium and cadmium in the fungi-microalgae symbiotic system

Microalgae and fungi in the fungi-microalgae symbiotic system(FMSS) can solve the problems of deep purification of heavy metals in wastewater and harvesting of microalgae cell by synergistic interaction. Therefore, it is of great significance to use the FMSS for remediation of heavy metal pollution. However, at present, the immobilization and transformation mechanism of heavy metals in the FMSS is not clear, which limits the development and industrial application of the FMSS with high adsorption performance, high selectivity, and high tolerance. In this study, the FMSS constructed using Aspergillus funigatus and Synechocystis sp. PCC6803, was used as the research object to explore heavy metal adsorption performance. Under optimal conditions, the adsorption efficiencies of Cd(II) and Cr(VI) were as high as 90.02% and 80.03%, respectively. The adsorption process was controlled by both internal and external diffusion. Extracellular absorption was dominant, and intracellular absorption was secondary. XRD, XPS, SEM-EDX and TEM-EDX results revealed that ionic crystals and precipitates (Cd(OH)₂, CdCO₃, calcium oxalate crystals, Cr(OH)₃, Cr₂O₃, and CrCl₃) were formed after adsorption. The adsorption of Cr(VI) involved the reduction of Cr(VI). Functional groups, such as amino, carboxyl, aldehyde, and ether groups, on the cell surface also interact with heavy metal ions. To summarize, by constructing the FMSS, optimizing the symbiosis conditions, exploring the adsorption and accumulation rules of Cd(II) and Cr(VI) inside and outside the cells in the system, and revealing the molecular response mechanism, we were able to establish a theoretical basis for further understanding the interaction between the FMSS and heavy metals.

The mitigation mechanism of hesperidin on deoxynivalenol toxicity in grass carp hepatocytes via decreasing ROS accumulation and inhibiting JNK phosphorylation

Deoxynivalenol (DON), a crucial kind of mycotoxin, is found globally present in the contaminated cereal crops including wheat, barley, maize and rice. Hesperidin (HDN) is a flavonoid with a variety of biological activities found in high concentrations in citrus fruits. However, the potential protective effects of HDN on cell damage under DON toxicity, and the role of oxidative stress, inflammation, autophagy and apoptosis in it, remain unclear. Therefore, we treated grass carp (Ctenopharyngodon idellus) liver cells (L8824 cell) with DON and HDN for 24 h. The results showed that DON exposure caused a higher ROS accumulation, activated inflammation, autophagy and apoptosis, induced the expression of cytokines (NF-kappaB, TNF-α, IL-1β, IL-6), triggered BCL2/BAX-mediated apoptosis and LC3B/P62-dependent autophagy in the L8824 cell line. Moreover, HDN reduced DON exposure-induced inflammation and autophagy by decreasing ROS accumulation and reduced DON exposure-induced apoptosis by inhibiting JNK phosphorylation. These results partly explained the mechanism of biological threat on fish under DON exposure and the potential application value of HDN in aquaculture.

Roles of selenoprotein K in oxidative stress and endoplasmic reticulum stress under selenium deficiency in chicken liver

Selenoprotein K (SELENOK) is a major part of selenoprotein family. Selenoproteins have been proven playing vital roles in a variety of physiological processes. However, as a necessary supplement to the body of trace elements, how SELENOK regulates necroptosis in chicken liver has none clear claim. The purpose of this study was to cover the mechanism of SELENOK act in necroptosis of chicken liver. By feeding Se-deficiency diet for 1-day-old hyline chickens, we successfully built SELENOK-deficiency and discussed the regulation SELENOK have done. The test of liver function showed there has dysfunction appeared in the -Se groups. Results of TEM showed necroptosis occurred in the 35-Se group. After that western blot and qRT-PCR results prompted us SELENOK-deficiency caused large accumulation of ROS, enhanced endoplasmic reticulum stress, abnormally elevated HSPs family expression, and activated RIPK1-RIPK3 complex. In order to show the regulation of SELENOK in chicken liver, we artificially knocked off SELENOK gene in LMH cells. Through AO/EB staining we also found necroptosis in the siRNA-Se group. Furthermore, the results in LMH cells were coincided with those in chicken (Gallus gallus) liver. Our experiment clarified the molecular mechanism of SELENOK in the regulation and liver necroptosis, and provided reference for the healthy feeding mode of broilers.

Decreased thioredoxin reductase 3 expression promotes nickel-induced damage to cardiac tissue via activating oxidative stress-induced apoptosis and inflammation

Thioredoxin reductase 3 (Txnrd3) plays a crucial role in antioxidant and anti-cancer activities, and sperm maturation. The damage of heavy metals, including Nickel (Ni), is the most prominent harm in social development, and hampering Txnrd3 might exacerbate Ni-induced cardiac damage. In this study, a total of 160 8-week-old C57BL/N male mice with 25-30 g weight of Txnrd3+/+ wild-type and Txnrd3-/- homozygote-type were randomly divided into eight groups. The mice in the control and Ni groups were gavaged with distilled water and a freshly prepared 10 mg/kg NiCl₂ solution. Melatonin (Mel) groups were administered at a concentration of 2 mg/kg for 21 days at the mice's 0.1 ml/10 g body weight. Ni exposure up-regulated the messenger RNA (mRNA) levels of mitochondrial apoptosis (caspase-3, caspase-9, cytochrome c, p53, and BAX), autophagy (LC3, ATG 1, ATG 7, and Beclin-1), and inflammation (TNF-α, COX 2, IL-1β, IL-2, IL-6, and IL-7)-related markers, but down-regulated the mRNA levels of BCL-2, p62 and mTOR (p < .05). Ni exposure decreased the expression of BCL-2 and p62 protein but increased the expression levels of caspase-3, caspase-9, cytochrome c, p53, BAX, ATG 7, Beclin-1, TNF-α, COX 2, IL-1β and IL-2 protein (p < .05). Ni increased the contents of glutathione disulfide (GSSG) and malondialdehyde (MDA) and decreased the activities of catalase (CAT) and total superoxide dismutase (T-SOD) (p < .05). Decreased Txnrd3 expression significantly exacerbated changes compared to the Ni exposure (p < .05). Mel significantly attenuated these changes, but the effect decreased when Txnrd3 was inhibited (p < .05). In conclusion, decreased Txnrd3 expression promoted Ni-induced mitochondrial apoptosis and inflammation via oxidative stress and aggravated heart damage in mice. Decreased Txnrd3 expression significantly reduced the protective effect of Mel to Ni exposure.

Mechanism of evodiamine blocking Nrf2/MAPK pathway to inhibit apoptosis of grass carp hepatocytes induced by DEHP

Di (2-ethylhexyl) phthalate (DEHP) is often used as a plasticizer for plastic products, and its excessive use can cause irreversible damage to aquatic animals and humans. Evodiamine (EVO) is an alkaloid component in the fruit of Evodia rutaecarpa, which has antioxidant and detoxification functions. To investigate the toxic mechanism of DEHP on grass carp (Ctenopharyngodon idellus) hepatocyte cell line (L8824) and the therapeutic effect of evodiamine, an experimental model of L8824 cells exposed to 800 μM DEHP and/or 10 μM EVO for 24 h was established. Flow cytometry, AO/EB fluorescence staining, real-time quantitative PCR, and western blot were used to detect the degree of cell injury, oxidative stress level, MAPK signaling pathway relative genes, and the expression of apoptosis-related molecules. The results showed that DEHP exposure could significantly increase the level of reactive oxygen species (ROS), inhibit the activities of antioxidant enzymes (CAT, SOD, GSH-Px), and cause the accumulation of MDA. DEHP also activated MAPK signaling pathway-related molecules (JNK, ERK, P38 MAPK), and then up-regulated the expression of pro-apoptotic factors Bcl-2-Associated X (Bax) and caspase 3, while inhibiting the anti-apoptotic factor B-cell lymphoma-2 (Bcl-2). In addition, EVO can also promote the dissociation of nuclear factor-E2-related factor 2 (Nrf2) into the nucleus, reduce the level of ROS and the occurrence of oxidative stress in grass carp hepatocytes, down-regulate the MAPK pathway, alleviate DEHP-induced apoptosis, and restore the expression of antioxidant genes. These results indicated that evodiamine could block Nrf2/MAPK pathway to inhibit DEHP-induced apoptosis of grass carp hepatocytes.

Polyethylene microplastics trigger cell apoptosis and inflammation via inducing oxidative stress and activation of the NLRP3 inflammasome in carp gills

Microplastics cause varying degrees of damage to aquatic organisms. Exposure to microplastics contaminated water, the gills are among the first tissues, after the skin, to be affected by microplastics. As an essential immune organ, prolonged stimulation by microplastics disrupts immune function not only in the gills but throughout the body, yet the underlying mechanisms remain elusive. A model of gill injury from exposure to polyethylene (PE) microplastics was developed in this study. H&E staining revealed that polyethylene microplastics caused gill inflammation, vascular remodeling, and mucous cell proliferation. An increase in collagen indicates severe tissue damage. Additional analysis showed that polyethylene microplastics profoundly exacerbated oxidative stress in the gills. TUNEL assay demonstrated cell apoptosis induced by polyethylene microplastic. The mRNA levels were subsequently quantified using RT-PCR. The results showed that polyethylene microplastics increased the expression of the nuclear factor-κB (NF-κB) pathway (NF-κB p65, IKKα, IKKβ) and apoptosis biomarkers (p53, caspase-3, caspase-9, and Bax). Nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) inflammasomes, which is an influential component of innate immunity, were overactive. What's more, the pro-inflammatory factors (TNF-α, IFN-γ, IL-2, IL-6, IL-8, IL-1β) that induce immune disorder also increased significantly, while the anti-inflammatory factors (IL-4, IL-10) decreased significantly. These results suggested that oxidative stress acted as an activation signal of apoptosis triggered by the NF-κB pathway and activating the NLRP3 inflammasome to promote inflammatory immune responses. The present study provided a different target for the prevention of toxin-induced gill injury under polyethylene microplastics.

Targeting Tumor Microenvironment by Metal Peroxide Nanoparticles in Cancer Therapy

Solid tumors have a unique tumor microenvironment (TME), which includes hypoxia, low acidity, and high hydrogen peroxide and glutathione (GSH) levels, among others. These unique factors, which offer favourable microenvironments and nourishment for tumor development and spread, also serve as a gateway for specific and successful cancer therapies. A good example is metal peroxide structures which have been synthesized and utilized to enhance oxygen supply and they have shown great promise in the alleviation of hypoxia. In a hypoxic environment, certain oxygen-dependent treatments such as photodynamic therapy and radiotherapy fail to respond and therefore modulating the hypoxic tumor microenvironment has been found to enhance the antitumor impact of certain drugs. Under acidic environments, the hydrogen peroxide produced by the reaction of metal peroxides with water not only induces oxidative stress but also produces additional oxygen. This is achieved since hydrogen peroxide acts as a reactive substrate for molecules such as catalyse enzymes, alleviating tumor hypoxia observed in the tumor microenvironment. Metal ions released in the process can also offer distinct bioactivity in their own right. Metal peroxides used in anticancer therapy are a rapidly evolving field, and there is good evidence that they are a good option for regulating the tumor microenvironment in cancer therapy. In this regard, the synthesis and mechanisms behind the successful application of metal peroxides to specifically target the tumor microenvironment are highlighted in this review. Various characteristics of TME such as angiogenesis, inflammation, hypoxia, acidity levels, and metal ion homeostasis are addressed in this regard, together with certain forms of synergistic combination treatments.

Triclocarban evoked neutrophil extracellular trap formation in common carp (Cyprinus carpio L.) by modulating SIRT3-mediated ROS crosstalk with ERK1/2/p38 signaling

Triclocarban (TCC), an antimicrobial ingredient in personal care products, is associated with immunosuppression and physiological dysfunctions of aquatic organisms. The aim of this study was to investigate whether TCC can induce common carp NETosis (neutrophil death by neutrophil extracellular trap (NET) release) and then to attempt to identify the potential molecular mechanisms. Herein, scanning electron microscopy and flow cytometric assays showed that revealed that TCC triggers DNA-containing web-like structures and increases extracellular DNA content. In the proteomic analysis, we observed that NET-related proteins, extracellular regulated protein kinase (Mapk1, Mapk14, Jak2) and apoptotic protein (caspase3) were significantly increased, and defender against cell death 1 (Dad1) was significantly decreased after TCC treatments. Meanwhile, we confirmed that TCC stress can trigger NETosis in common carp by activating the reactive oxygen species (ROS)/ERK1/2/p38 signaling. We think that the upregulated NDUFS1 expression is closely related to oxidative stress induced by TCC. Importantly, we discovered that SIRT3 expression was significantly decreased in the process of TCC-induced NETs. Importantly, pretreatment with the SIRT3 agonist honokiol (HKL) effectively suppressed TCC-induced NET release. In contrast, the SIRT3 antagonist 3-TYP escalated TCC-induced NET formation. Mechanistically, SIRT3 degradation serves as a potential mediator for regulating oxidative stress crosstalk between ERK1/2/p38 signals in the process of TCC-induced NET formation. These findings unveil new insights into the TCC-evoked health risk of fish and other aquatic organisms and suggest that SIRT3 is a potential pharmacological intervention target to alleviate TCC-induced common carp NETosis.

ROS-mediated PPAR/RXR inhibition contributes to acetochlor-induced apoptosis and autophagy in Ctenopharyngodon idella hepatic cells

Acetochlor is a high-volume herbicide whose widespread use threatens ecosystems and affects aquaculture. Apoptosis and autophagy are important causes of hepatotoxicity caused by toxicants, which can be mediated by oxidative stress and the inhibition of PPAR/RXR pathway. However, the mechanism of acetochlor on fish hepatocyte damage still needs to be further investigated. Therefore, we treated the Ctenopharyngodon idella hepatic cell line (L8824 cells) with different concentrations (10, 20, and 40 μM) of acetochlor and/or ROS scavenger NAC (1 mM) for 24 h. The results showed that acetochlor decreased the cell viability in a dose-dependent manner. AO/EB staining and flow cytometry verified the increased apoptotic rates. Quantitative analysis of gene expression levels or protein expression levels displayed that the expression levels of Beclin1, P62, LC3B, BAX, and cleaved Casp3 were increased, and the expression of BCL2 was reduced. Besides, we detected the increased ROS contents and decreased PPAR/RXR pathway expressions after acetochlor treatment. The clearance of ROS alleviated the inhibition of the PPAR/RXR pathway and lightened apoptosis and autophagy under acetochlor stress. Overall, these results revealed that acetochlor exposure triggered BCL2/BAX/Casp3-cascaded apoptosis and Beclin1-dependent autophagy through ROS-mediated PPAR/RXR inhibition. The results partially explain the toxicological mechanism of acetochlor and provide targets for the development of its antidote.

Melatonin administration alleviates 2,2,4,4-tetra-brominated diphenyl ether (PBDE-47)-induced necroptosis and secretion of inflammatory factors via miR-140-5p/TLR4/NF-κB axis in fish kidney cells

2,2,4,4-tetra-brominated diphenyl ether (PBDE-47)-the dominant homologue of polybrominated diphenyl ethers-is a toxic environmental pollutant in the aquatic environment that continuously exists and bioaccumulates in the aquatic food chain. In experimental disease models, melatonin (MEL) has been reported to attenuate necroptosis and inflammatory responses. To further explore the mechanism underlying PBDE-47 toxicity and the mitigative impact of MEL detoxification, in this study, fish kidney cell models of PBDE-47 poisoning and/or MEL treatment were developed. The Ctenopharyngodon idellus kidney (CIK) cell line was treated with PBDE-47 (100 μM) and/or MEL (60 μM) for 24 h. Experimental data suggest that PBDE-47 exposure resulted in the enhancement of cytoplasmic Ca²⁺ concentration, induction of calcium dysmetabolism, decrease in the miR-140-5p miRNA level, upregulation of Toll-like Receptor 4 (TLR4) and nuclear factor-kappaB (NF-κB), triggering of receptor interacting serine/threonine kinase-induced necroptosis, and NF-κB pathway mediated secretion of inflammatory factors in CIK cells. PBDE-47-induced CIK cell damage could be mitigated by MEL through the regulation of calcium channels and the restoration of disorders of the miR-140-5p/TLR4/NF-κB axis. Overall, MEL relieved PBDE-47-induced necroptosis and the secretion of inflammatory factors through the miR-140-5p/TLR4/NF-κB axis. These findings enrich the current understanding of the toxicological molecular mechanisms of the PBDE-47 as well as the detoxification mechanisms of the MEL.

Immunosuppression participated in complement activation-mediated inflammatory injury caused by 4-octylphenol via TLR7/IκBα/NF-κB pathway in common carp (Cyprinus carpio) gills

4-octylphenol (4-OP), a toxic estrogenic environmental pollutant, can threaten aquatic animal and human health. However, toxic effect of 4-OP on fish has not been reported. To investigate molecular mechanism of gill poisoning caused by 4-OP exposure, a carp 4-OP poisoning model was established, and then blood and gills were collected on day 60. The results demonstrated that gill was a target organ attacked by 4-OP, and exposure to 4-OP caused carp gill inflammatory injury. There were 1605 differentially expressed genes (DEGs, including 898 up-regulated DEGs and 707 down-regulated DEGs). KEGG and GO were used to further analyze obtained 1605 DEGs, indicating that complement activation, immune response, and inflammatory response participated in the mechanism of 4-OP-caused carp gill inflammatory injury. Our data at transcription level further revealed that 4-OP caused complement activation through triggering complement component 3a/complement component 3a receptor (C3a/C3aR) axis and complement component 5a/complement component 5a receptor 1 (C5a/C5aR1) axis, induced immunosuppression through the imbalances of T helper (Th) 1/Th2 cells and regulatory T (Treg)/Th17 cells, as well as caused inflammatory injury via toll like receptor 7/inhibitor kappa B alpha/nuclear factor-kappa B (TLR7/IκBα/NF-κB) pathway. Taken together, immunosuppression participated in complement activation-mediated inflammatory damage in carp gills after 4-OP treatment. The findings of this study will provide pioneering information and theoretical support for the mechanism of 4-OP poisoning, and will provide reference for the assessment of estrogenic environmental pollution risk.

The protective effect of selenoprotein M on non-alcoholic fatty liver disease: the role of the AMPKα1-MFN2 pathway and Parkin mitophagy

Non-alcoholic fatty liver disease (NAFLD) is related to a dysregulation of mitophagy, a process that is not fully understood. Parkin-related mitophagy can sustain mitochondrial homeostasis and hepatocyte viability. Herein, we report that selenoprotein M (SELENOM) plays a central role in maintaining mitophagy in high-fat diet (HFD)-mediated NAFLD. We show that SELENOM was significantly downregulated in the liver of HFD-fed mice. SELENOM deletion aggravated HFD-mediated hepatic steatosis, inflammation, and fibrosis; accompanied by enhanced fatty acid oxidation and oxidative stress in the liver. Molecular analyses show that lipotoxicity was related to increased mitochondrial apoptosis as evidenced by enhanced mitochondrial ROS production, and attenuation of mitochondrial potential in the liver of HFD-fed SELENOM-/- mice. Additionally, SELENOM deletion reduced mitophagy and aggravated hepatic injury in NAFLD. Mechanistically, SELENOM overexpression activated Parkin-mediated mitophagy to reduce mitochondrial apoptosis and remove HFD-damaged mitochondria. We further found that SELENOM regulates Parkin expression via the AMPKα1-MFN2 pathway; blockade of AMPKα1 prevented SELENOM activation of Parkin-mediated mitophagy. Our work identified SELENOM downregulation as a possible explanation for the defective mitophagy in NAFLD. Thus, targeting SELENOM may be potential new therapeutic modalities for NAFLD treatment.