Antagonistic effect of VDR/CREB1 pathway on cadmium-induced apoptosis in porcine spleen

Lycopene regulates Nrf2 to Ameliorate Sulfamethoxazole -induced renal injury and apoptosis via inhibiting oxidative stress and Endoplasmic Reticulum stress

The overuse and long-term existence of Sulfamethoxazole (SMZ) in aquatic system have led to adverse effects on non-target organisms, remaining a challenge for aquaculture and human health. This study investigated whether the natural carotenoid lycopene (LYC, 10 mg/kg B.W.) could be used as a candidate to alleviate SMZ (0.3 μg/L)-induced kidney injury in grass carp; the underlying mechanisms were deciphered in vivo and in vitro. Transmission electron microscopy and TUNEL were observed to detect renal injury, structure and function. Various indexes belong to apoptosis (Bcl-2 and caspase families) and its upstream cellular processes, including endoplasmic reticulum stress and autophagy and the Nrf2 pathway were detected in kidney to suggest the alleviating effect of LYC on SMZ-induced renal toxicity. The same renal protection of LYC against SMZ-induced autophagic activation, apoptotic cell death, and Nrf2 blockage, were further confirmed in cultured grass carp kidney cells (CIK). Nrf2 siRNA abrogated LYC-dependent protection of the nephrocytes against SMZ-induced higher production of ROS and apoptosis level. LYC is demonstrated as a potential feed additive for both preventing and alleviating SMZ-induced renal toxicity in aquatic organisms.

Adverse effects of cadmium on lymphoid organs, immune cells, and immunological responses

Humans and animals possess robust immune systems to safeguard against foreign pathogens. However, recent reports suggest a greater incidence of immunity breakdown due to exposure to environmental pollutants, with heavy metals emerging as potential candidates in such immuno-toxicological studies. While we have extensive data on the general toxicity resulting from exposure to heavy metals, comprehensive documentation of their role as immune disruptors remains scarce. Cd (Cadmium) exerts immunomodulation by interfering with immune organs and cells, leading to altered structure, physiology, and function, thereby inducing symptoms of immune deregulation, inflammation and/or autoimmunity. This review aims to summarize the link between Cd exposure and immune dysfunction, drawing from case studies on exposed human subjects, as well as research conducted on various model organisms and in-vitro culture systems.

Population Pharmacokinetic Model of Vitamin D3 and Metabolites in Chronic Kidney Disease Patients with Vitamin D Insufficiency and Deficiency

Vitamin D insufficiency and deficiency are highly prevalent in patients with chronic kidney disease (CKD), and their pharmacokinetics are not well described. The primary study objective was to develop a population pharmacokinetic model of oral cholecalciferol (VitD3) and its three major metabolites, 25-hydroxyvitamin D3 (25D3), 1,25-dihydroxyvitamin D3 (1,25D3), and 24,25-dihydroxyvitamin D3 (24,25D3), in CKD patients with vitamin D insufficiency and deficiency. CKD subjects (n = 29) were administered one dose of oral VitD3 (5000 I.U.), and nonlinear mixed effects modeling was used to describe the pharmacokinetics of VitD3 and its metabolites. The simultaneous fit of a two-compartment model for VitD3 and a one-compartment model for each metabolite represented the observed data. A proportional error model explained the residual variability for each compound. No assessed covariate significantly affected the pharmacokinetics of VitD3 and metabolites. Visual predictive plots demonstrated the adequate fit of the pharmacokinetic data of VitD3 and metabolites. This is the first reported population pharmacokinetic modeling of VitD3 and metabolites and has the potential to inform targeted dose individualization strategies for therapy in the CKD population. Based on the simulation, doses of 600 International Unit (I.U.)/day to 1000 I.U./day for 6 months are recommended to obtain the target 25D3 concentration of between 30 and 60 ng/mL. These simulation findings could potentially contribute to the development of personalized dosage regimens for vitamin D treatment in patients with CKD.

Identification of the Hub Genes Linked to Lead (IV)-Induced Spleen Toxicity Using the Rat Model

Exposure to lead (Pb) has harmful effects on the organs of both humans and animals, particularly the spleen. However, the precise mechanisms through which Pb (IV) exposure leads to spleen toxicity remain unclear. Hence, this study aimed to identify the key genes and signaling pathways involved in spleen toxicity caused by Pb (IV) incubation. We obtained the dataset GSE59925 from the Gene Expression Omnibus, which included spleen samples treated with lead tetraacetate (PbAc4) as well as control samples on the 1st and 5th day. Through differential expression analysis, we identified 607 and 704 differentially expressed genes (DEGs) in the spleens on the 1st and 5th day following PbAc4 treatment, respectively, with 245 overlapping DEGs between the two time points. Gene ontology analysis revealed that the commonly shared DEGs were primarily involved in signal transduction, drug response, cell proliferation, adhesion, and migration. Pathway analysis indicated that the common DEGs were primarily associated with MAPK, TNF, cAMP, Hippo, and TGF-β signaling pathways. Furthermore, we identified the hub genes such as CXCL10, PARP1, APOE, and VDR contributing to PbAc4-induced spleen toxicity. This study enhances our understanding of the molecular mechanisms underlying Pb (IV) toxicity in the spleen.

Integrating Transcriptomics and Proteomics to Characterize the Intestinal Responses to Cadmium Exposure Using a Piglet Model

Cadmium (Cd) is a heavy metal element with a wide range of hazards and severe biotoxicity. Since Cd can be easily accumulated in the edible parts of plants, the exposure of humans to Cd is mainly through the intake of Cd-contaminated food. However, the intestinal responses to Cd exposure are not completely characterized. Herein, we simulated laboratory and environmental Cd exposure by feeding the piglets with CdCl2-added rice and Cd-contaminated rice (Cdcr) contained diet, as piglets show anatomical and physiological similarities to humans. Subsequent analysis of the metal element concentrations showed that exposure to the two types of Cd significantly increased Cd levels in piglets. After verifying the expression of major Cd transporters by Western blots, multi-omics further expanded the possible transporters of Cd and found Cd exposure causes wide alterations in the metabolism of piglets. Of significance, CdCl2 and Cdcr exhibited different body distribution and metabolic rewiring, and Cdcr had stronger carcinogenic and diabetes-inducing potential. Together, our results indicate that CdCl2 had a significant difference compared with Cdcr, which has important implications for a more intense study of Cd toxicity.

Effects of environmentally relevant cypermethrin and sulfamethoxazole on intestinal health, microbiome, and liver metabolism in grass carp

The incorrect use of antibiotics and pesticides poses significant risks of biological toxicity. Their simultaneous exposure could jeopardize fish health and hinder sustainable aquaculture. Here, we subjected grass carp to waterborne cypermethrin (0.65 μg/L) or/and sulfamethoxazole (0.30 μg/L) treatments for a duration of 6 weeks. We closely monitored the effects on intestinal function, the intestinal microbiome, and the liver metabolome. The results revealed that exposure to waterborne cypermethrin or/and sulfamethoxazole compromised intestinal barrier function and decreased the expression of intestinal tight junction proteins. Additionally, heightened levels of pro-inflammatory cytokines in the intestines and reduced antioxidant levels indicated systemic inflammation and oxidative stress, with more severe effects observed in the combined exposure group. 16S rRNA sequencing of intestinal tissues suggested Firmicutes play a key role in the intestinal microbiota. GC/MS metabolomics of the liver showed more differential metabolites (56) in the co-exposure group compared to cypermethrin (45) or sulfamethoxazole (32) alone, indicating greater toxicological effects with combined exposure. Our analyses also suggest that ATP-binding cassette transporters could serve as a novel endpoint for assessing the risk of pesticide and antibiotic mixtures in grass carp. In summary, this study underscores the potential ecological risks posed by antibiotics and pesticides to aquatic environments and products. It emphasizes the importance of the gut-liver axis as a comprehensive pathway for assessing the toxicity in fish exposed to environmental contaminants.

The mechanism of cadmium exposure-induced lymph node necroptosis and inflammation in piglets: Activation of CYP450 through VDR / CREB1 pathway

Cadmium (Cd) is toxic non-essential heavy metal that precipitates adverse health effects in humans and animals, but the effect of Cd on lymph node toxicity of piglets is still unclear. In order to explore the possible molecular mechanism of Cd toxicity to lymph nodes of piglets, ten 6-week-old male weaned piglets were randomly divided into two groups, C group and Cd group. Group C was fed with basal diet, while group Cd was fed with basal diet supplemented with CdCl2 (20 mg/kg) for 40 days, the pigs were euthanized and the mesenteric, inguinal and submandibular lymph nodes (MLN, ILN, SLN) were collected. The results indicated that Cd could induce the inflammatory cell infiltration, microvascular hemorrhage, microthrombosis and cell necrosis in MLN, ILN and SLN of piglets, induced Cytochrome P450 proteins (CYP1A1、CYP2E1、CYP2A1 and CYP3A2) mRNA levels and the protein levels of Vitamin D receptor (VDR) and cAMP response element binding protein 1 (CREB1). In addition, Cd exposure upregulated the mRNA and protein levels of dynamin-related protein 1 (DRP1), receptor-interacting protein kinase 3 (RIP3), mixed lineage kinase domain-like protein (MLKL), and increased tumor necrosis factor-α (TNFα), interferon-γ (IFNγ), interleukin-2 (IL-2), interleukin-4 (IL-4), cyclooxygenase 2 (COX-2) protein levels, and the damage degree of three kinds of lymph nodes was similar after Cd exposure. In general, these results manifest that Cd exposure regulates VDR/CREB1 pathway, activates CYP450s, induces necroptosis of lymph nodes, and leads to inflammation.

Cadmium induces apoptosis by miR-9-5p targeting PTEN and regulates the PI3K/AKT pathway in the piglet adrenal gland

Cadmium (Cd) is an environmental pollutant that can cause endocrine organ damage. To explore the effect of subacute CdCl₂ exposure on piglet adrenal gland tissue and its mechanism based on the establishment of this model, bioinformatics, TUNEL assay, western blot (WB), and qRT-PCR methods were used to detect related indicators. The results showed that after Cd exposure, antioxidant enzymes decreased, heat shock protein increased, and miR-9-5p-gene of phosphatase and tensin homolog (PTEN) upregulates the phosphatidylinositol-3-kinase (PI3K/AKT) pathway. After this pathway was activated, the expression of the apoptosis-related factors cysteinyl aspartate-specific proteinase 3 and 9 (caspase 3 and 9), B-cell lymphoma-2-associated X (BAX) was increased sharply, and the expression of B-cell lymphoma-2 (BCL2) was significantly decreased. The changes in these indicators indicate that Cd exposure induces apoptosis and causes tissue damage in the adrenal gland of piglets. This study aims to reveal the toxic effects of CdCl₂ in animals and will provide new ideas for the toxicology of Cd.

Selenium Deficiency Induces Autophagy in Chicken Bursa of Fabricius Through ChTLR4/MyD88/NF-κB Pathway

To explore the role of ChTLR4/MyD88/NF-κB signaling pathway on autophagy induced by selenium (Se) deficiency in the chicken bursa of Fabricius, autophagosome formation in the bursa of Fabricius was observed by transmission electron microscopy. Quantitative real-time PCR (qRT-PCR) and Western blot were used to detect the expression of ChTLR4 and its signaling pathway molecules (MyD88, TRIF, and NF-κB), inflammatory factors (IL-1β, IL-8, and TNF-α), and autophagy-related factors (ATG5, Beclin1, and LC3-II) in the Se-deficient chicken bursa of Fabricius at different ages. The results showed that ChTLR4/MyD88/NF-κB signaling pathway was activated in the chicken bursa of Fabricius and autophagy was induced at the same time by Se deficiency. In order to verify the relationship between the autophagy and ChTLR4/MyD88/NF-κB signaling pathway, HD11 cells were used to establish the normal C group, low Se group, and low Se + TLR4 inhibitor (TAK242) group. The results demonstrated that autophagy could be hindered when the TLR4 signaling pathway was inhibited under Se deficiency. Furthermore, autophagy double-labeled adenovirus was utilized to verify the integrity of autophagy flow induced by Se deficiency in HD11 cells. The results showed that it appeared to form a complete autophagy flow under the condition of Se deficiency and could be blocked by TAK242. In summary, we found that Se deficiency was involved in the chicken bursa of Fabricius autophagy occurring by activating the ChTLR4/MyD88/NF-κB pathway.

Exosomal mediated signal transduction through artificial microRNA (amiRNA): A potential target for inhibition of SARS-CoV-2

Exosome trans-membrane signals provide cellular communication between the cells through transport and/or receiving the signal by molecule, change the functional metabolism, and stimulate and/or inhibit receptor signal complexes. COVID19 genetic transformations are varied in different geographic positions, and single nucleotide polymorphic lineages were reported in the second waves due to the fast mutational rate and adaptation. Several vaccines were developed and in treatment practice, but effective control has yet to reach in cent presence. It was initially a narrow immune-modulating protein target. Controlling these diverse viral strains may inhibit their transuding mechanisms primarily to target RNA genes responsible for COVID19 transcription. Exosomal miRNAs are the main sources of transmembrane signals, and trans-located miRNAs can directly target COVID19 mRNA transcription. This review discussed targeted viral transcription by delivering the artificial miRNA (amiRNA) mediated exosomes in the infected cells and significant resources of exosome and their efficacy.

TRAF2/ASK1/JNK Signaling Pathway Is Involved in the Lung Apoptosis of Swine Induced by Cadmium Exposure

Cadmium (Cd), a toxic heavy metal, exists widely in the environment, which can enter organisms through a variety of ways and cause damage to various organs and tissues. However, the mechanism of lung toxicity in swine after Cd exposure is still unclear. To explore the molecular mechanism of swine lung damage caused by Cd exposure, we established the model of Cd exposure, and Cd chloride (20 mg/kg CdCl₂) was added to the diet of swine for continuous exposure for 40 days. TUNEL staining showed that the apoptosis of swine lung increased significantly after Cd exposure. Meanwhile, the results of qRT-PCR showed that Cd induced oxidative stress and inhibited the expression of antioxidant enzymes including CAT, GCLM, GST, SOD, and GSH-px in lung tissue. Cd exposure activated mitochondrial apoptosis pathway via the TRAF2/ASK1/JNK signaling pathway. In brief, we considered that Cd exposure causes oxidative stress in lung and induces lung cell apoptosis through the TRAF2/ASK1/JNK pathway and increases the expression of HSPs to resist the toxicity of Cd. Our research enriches the theoretical basis of Cd toxicity and provides reference for comparative medicine.

Subacute cadmium exposure modulates Th1 polarization to trigger ER stress-induced porcine hepatocyte apoptosis via regulation of miR-369-TNFα axis

Cadmium (Cd), as a common environmental pollutant, has been reported to cause T lymphocyte dysfunction and cell apoptosis in multiple organs. However, whether subacute Cd exposure can induce apoptosis of hepatocytes and the relationship with Th1/Th2 imbalance were still unclear. In this study, ten 6-week-old piglets were selected and randomly assigned into two groups, the control group and the Cd group. The control group was fed with the standard diet, and for the Cd group, the standard diet was supplemented with 20 mg/kg CdCl2; liver tissue was collected on the 40th day of the experiment. Immunofluorescence, qRT-PCR, and western blot were performed to detect the expression of miR-369, Th1/Th2 biomarkers, endoplasmic reticulum (ER) stress-related genes, and apoptotic genes. TUNEL assay was applied to stain apoptotic hepatocytes. In the Cd group, the apoptosis of hepatocytes was significantly increased, and associated with the declined expression of miR-369, Th1 polarization, the elevated expression of ER stress pathway genes and their downstream pro-apoptosis genes, and downregulated expression of anti-apoptotic genes. These results manifest that subacute Cd exposure mediates Th1 polarization to promote ER stress-induced porcine hepatocyte apoptosis via regulating miR-369-TNFα. These results not only provide a basis for the enrichment of Cd toxicology but also support a theoretical foundation for the prevention and therapy of Cd poisoning. Schematic diagram illustrating the proposed mechanism of subacute cadmium exposure modulates Th1 polarization to trigger ER stress-induced porcine hepatocyte apoptosis via regulation of miR-369-TNFα axis.

Oxidative stress is involved in the activation of NF-κB signal pathway and immune inflammatory response in grass carp gill induced by cypermethrin and/or sulfamethoxazole

At present, the concentration of environmental pollutants, such as pesticides and antibiotics exposed in environment, especially in aquatic environment is increasing. Research on environmental pollutants has exploded in the last few years. However, studies on the combined effects of pesticides and antibiotics on fish are rare, especially the toxic damage to gill tissue is vague. In this paper, cypermethrin (CMN) and sulfamethoxazole (SMZ) were analyzed and found that there was a strong correlation between the pathways affected by the first 30 genes regulated by CMN and SMZ, respectively. Therefore, the toxic effects of CMN (0.651 μg L^-1) and/or SMZ (0.3 μg L^-1) on grass carp gill were studied in this paper. Histopathology, quantitative real-time PCR, and other methods were used to detect the tissue morphology, oxidative stress level, inflammation, and apoptosis-related indicators of the fish gills after exposure of 42 days. It was found that compared with the single exposure (CMN/SMZ) group, the combined exposure (MIX) group had a more pronounced oxidative stress index imbalance. At the same time, nuclear factor-κB (NF-κB) signal pathway was activated and immuno-inflammatory reaction appeared in MIX group. The expression of tumor necrosis factor (TNF-α) in the rising range is 2.94 times that of the C group, while the expression of interleukin 8 (IL-8) is as high as 32.67 times. This study reveals the harm of CMN and SMZ to fish, and provides a reference and basis for the rational use of pesticides and antibiotics.

Lycopene attenuates oxidative stress, inflammation, and apoptosis by modulating Nrf2/NF-κB balance in sulfamethoxazole-induced neurotoxicity in grass carp (Ctenopharyngodon Idella)

All drugs that can penetrate the blood-brain barrier (BBB) may lead to mental state changes, including the widely used anti-infective drug sulfamethoxazole (SMZ). Herein, we investigated whether lycopene (LYC) could ameliorate SMZ-induced brain injury and the postulated mechanisms involved. A total of 120 grass carps were exposed under SMZ (0.3 μg/L, waterborne) or LYC (10 mg/kg fish weight, diet) or their combination for 30 days. Firstly, brain injury induced by SMZ exposure was suggested by the damage of BBB (decreases of Claudins, Occludin and Zonula Occludens), and the decrease of neurotransmitter activity (AChE). Through inducing oxidative stress (elevations of malondialdehyde and 8-hydroxy-2 deoxyguanosine, inhibition of glutathione), SMZ increased the intra-nuclear level of NF-κB and its target genes (TNF-α and interleukins), creating an inflammatory microenvironment. As a positive feed-back mechanism, apoptosis begins with activation of pro-death proteins (Bax/Bcl-2) and activation of caspases (caspase-9 and caspase-3). Meanwhile, a compensatory upregulation of constitutive Nrf2 and its downstream antioxidative gene expression (NAD(P)H Quinone Dehydrogenase 1 and Heme oxygenase 1) and accelerated autophagy (increases of autophagy-related genes and p62 inhibition) were activated as a defense mechanism. Intriguingly, under SMZ stress, LYC co-administration decreased NF-κB/apoptosis cascades and restored Nrf2/autophagy levels. The neuroprotective roles of LYC make this natural compound a valuable agent for prevention SMZ stress in environment. This study suggests that LYC might be developed as a potential candidate for alleviating environmental SMZ stress in aquaculture.

MicroRNA-294 Regulates Apoptosis of the Porcine Cerebellum Caused by Selenium Deficiency via Targeting iNOS

Deficiency of the essential trace element selenium (Se) can lead to cell apoptosis, and various microRNAs (miRNAs) are known to participate in the regulation of apoptosis by regulating their target genes. In this study, we explore the effect of Se deficiency on porcine cerebellar cell apoptosis and the role of miRNA in this process. After constructing a low-Se pig model, we observed the porcine cerebellum through an electron microscope and observed obvious characteristics of apoptosis. Moreover, it was found that the expression of miR-294 in Se-deficient pigs was significantly lower than that in the control group. Through bioinformatics, qRT-PCR, western blot analysis, and other experimental techniques, we further confirmed that inducible nitric oxide synthase (iNOS) is one of the target genes of miR-294. Our experimental results show that Se deficiency can reduce the expression of miR-294 and increase both the expression of iNOS and the nitric oxide (NO) content (P < 0.01). The expression of heat shock proteins (HSPs, such as HSP70, HSP90, HSP60, HSP40, and HSP27) and mitochondrial pathway-related indicators, such as Bcl2-associated X protein (Bax), cytochrome C (Cyt-C), and cysteinyl aspartate-specific proteinases (caspase 3, caspase 7, and caspase 8), was upregulated (P < 0.05), and the expression of B cell lymphoma-2 (Bcl-2) was downregulated (P < 0.05). In summary, we believe that Se deficiency can lead to abnormal expression of miR-294 and HSPs; moreover, the mitochondrial apoptosis pathway is activated, which significantly enhances apoptosis of cerebellar cells in Se-deficient pigs. These results enrich the biological effects of Se deficiency.

MiR-182-5p/TLR4/NF-κB axis contributes to the protective effect of caffeic acid phenethyl ester against cadmium-induced spleen toxicity and associated damage in mice

Cadmium (Cd) is a toxic heavy metal pollutant that can be accumulated in organs including the spleen, thereby threatening human health. In this study, the effect of caffeic acid phenethyl ester (CAPE, a bioactive component of honeybee propolis) on CdCl2-induced spleen toxicity and underlying mechanisms were examined in mice. Histological examinations revealed that CAPE (10 μmol/kg/day b.w.) could mitigate spleen damage induced by CdCl2 (1.5 mg/kg/day b.w.) in mice. Compared to the mice treated only by CdCl2, CAPE administration increased the body weight while decreasing the spleen weight, spleen Cd content and spleen to body ratio of the CdCl2-treated mice. Western blot and ELISA tests revealed that CAPE suppressed CdCl2-induced inflammation (indicated by the decreases in the levels of inflammatory indictors). TUNEL and Western blot results showed that CAPE suppressed CdCl2-induced apoptosis through reducing the percentage of TUNEL-positive cells and regulating apoptosis factors. The antagonistic effect of CAPE against CdCl2-induced spleen toxicity was realized by increasing miR-182-5p expression to regulate the TLR4/NF-κB pathway. Therefore, CAPE could be a food-derived spleen protector to counteract Cd-induced spleen toxicity through alleviating apoptosis and inflammation via the miR-182-5p/TLR4/NF-κB axis.

Chlorpyrifos caused necroptosis via MAPK/NF-κB/TNF-α pathway in common carp (Cyprinus carpio L.) gills

Chlorpyrifos (CPF) is an organophosphate insecticide and can cause cell death of animals. In the study, the common carp were exposed to CPF at 0 μg/L (the control group), 1.16 μg/L (the low dose group), 11.6 μg/L (the medium dose group), and 116 μg/L (the high dose group), respectively. The carp were euthanized at the 30th day and gills were collected immediately. The ultrastructural and histopathological observations showed obvious necrosis characteristics and inflammatory injury in the CPF-treated groups. CPF exposure activated the MAPK pathway, in which the mRNA and protein expressions of extracellular signal-regulated (ERK), p38 MAP kinase (p38), and c-Jun N-terminal kinase (JNK) were increased; the mRNAs and proteins of NF-κB and TNF-α were activated; and the mRNAs and proteins of necroptosis related genes were changed (the mRNA and protein expression of RIPK1, RIPK3, MLKL, and FADD were increased and caspase-8 was decreased) with concentration dependency. Taken together, we concluded that CPF exposure activated the MAPK/NF-κB/TNF-α pathway, promoted inflammatory injure and evoked necroptosis in common carp gills. In addition, CPF-induced inflammation and necroptosis was concentration dependency. The toxic effects of CPF on gills provided data for both aquaculture and toxicological studies.

Zinc antagonizes common carp (Cyprinus carpio) intestinal arsenic poisoning through PI3K/AKT/mTOR signaling cascade and MAPK pathway

Arsenic (As) pollution is a serious and longstanding problem, which has obvious threaten to aquatic organisms. The study aimed to explore the mitigation effect of natural antioxidant zinc (Zn) on As toxicity in the foregut and midgut of common carp (Cyprinus carpio L.), and in-depth disclose related signal cascade. Carps were treated with Zn²⁺ (1 mg/L) and/or As³⁺ (2.83 mg/L) for a period of 30 days. Under As exposure, the foregut and midgut showed obvious burst of reactive oxygen species (ROS) and breakdown of antioxidant system. What followed is the activation of the endogenous and exogenous apoptotic pathways, and the rise of autophagy level prompted by the increase in LC3 II and the down-regulation of p62. Mitochondrial swelling, cristae fragmentation and autophagosomes were observed under the electron microscope, which also means the occurrence of apoptosis and autophagy. In addition, As induced the activation of p38 mitogen-activated protein kinase (MAPK), c-Jun N-terminal kinase (JNK) and the inhibition of extracellular signal-related kinase (ERK) in MAPK signaling, and up-regulated the level of autophagy through the inhibition of the phosphatidylinositol 3 kinase (PI3K)/AKT/ mammalian target of rapamycin (mTOR) signaling cascade. However, Zn supplementation has clearly reversed the above phenomenon, and it basically has no effect on foregut and midgut. In conclusion, this study shows that Zn can alleviate the damage caused by subchronic As exposure, which provides a reference for the use of Zn preparations in aquaculture.

H2S exposure induces cell death in the broiler thymus via the ROS-initiated JNK/MST1/FOXO1 pathway

Hydrogen sulfide (H₂S) is a common toxic gas in chicken houses that endangers the health of poultry. Harbin has a cold climate in winter, and the conflict between heat preservation and ventilation in poultry houses is obvious. In this study, we investigated the H₂S content in chicken houses during winter in Harbin and found that the H₂S concentration exceeded the national standard in individual chicken houses. Then, a model of H₂S exposure was established in an environmental simulation chamber. We also developed a NaHS exposure model of chicken peripheral blood lymphocytes in vitro. Proteomics analysis was used to reveal the toxicology of thymus injury in broilers, the FOXO signaling pathway was determined to be significantly enriched, ROS bursts and JNK/MST1/FOXO1 pathway activation induced by H₂S exposure were detected, and ROS played an important switch role in the JNK/MST1/FOXO1 pathway. In addition, H₂S exposure-induced thymus cell death involved immune dysregulation. Overall, the present study adds data for H₂S contents in chicken houses, provides new findings for the mechanism of H₂S poisoning and reveals a new regulatory pathway in immune injury.

Cadmium induces the thymus apoptosis of pigs through ROS-dependent PTEN/PI3K/AKT signaling pathway

Cadmium (Cd) is a transition metal that is toxic to living organisms in the environment and endangers living organisms. To explore whether Cd induces apoptosis in pig thymus and its possible mechanism, the role Cd induction of the PTEN/PI3K/Akt pathway in apoptosis of thymus cells was studied in pigs. We found that Cd exposure (the feed is treated with Cd) significantly increased Cd accumulation in the thymus of pigs. The TUNEL assay confirmed the typical apoptotic characteristics of thymus in Cd group. Moreover, in the Cd group, the activities of antioxidant indices decreased significantly, while the levels of oxidative stress indexes increased significantly, and the mRNA levels of GSH, CAT, Gpx1, GST, SOD1, and SOD2 decreased obviously. Moreover, the mRNA and protein levels of PTEN/PI3K/AKT and apoptosis-related genes were detected by qPCR and western blotting. The results show that the expressions of PI3K and AKT decreased, while the expression of PTEN increased, indicating that pathway activated. With the PTEN/PI3K/AKT pathway regulating, Bcl-2 expression decreased. Conversely, the mRNA and protein expression of apoptosis-related genes were up-regulated. In conclusion, accumulation of Cd in the pigs caused oxidative damage to immune tissues. In addition, Cd-induced oxidative stress activates the PTEN/PI3K/AKT pathway, inducing apoptosis in the thymus of pigs.

Effects of Cadmium Exposure on the Immune System and Immunoregulation

Cadmium (Cd), a biologically non-essential heavy metal, is widespread in the environment, including the air, water, and soil, and is widely present in foods and quantum dot preparations. Cd enters the body primarily through inhalation and ingestion. Its biological half-life in humans is 10-35 years; therefore, Cd poses long-term health risks. While most studies on Cd toxicity have focused on organ and tissue damage, the immunotoxicity of Cd has drawn increasing attention recently. Cd accumulates in immune cells, modulates the function of the immune system, triggers immunological responses, and leads to diverse health problems. Cd acts as an immunotoxic agent by regulating the activity and apoptosis of immune cells, altering the secretion of immune cytokines, inducing reactive oxygen species (ROS) production and oxidative stress, changing the frequency of T lymphocyte subsets, and altering the production of selective antibodies in immune cells. This review summarizes the immunological toxicity of Cd, elucidates the mechanisms underlying Cd toxicity in terms of innate immunity and adaptive immunity, and discusses potential strategies to alleviate the adverse effects of Cd on the immune system.

Selenium-deficient diet induces inflammatory response in the pig adrenal glands by activating TLR4/NF-κB pathway via miR-30d-R_1

Selenium (Se) is an important trace element to maintain the body's dynamic balance. Lack of Se can cause inflammation. Studies have shown that inflammation often leads to disorders of the hypothalamic-pituitary-adrenal axis, but the mechanism by which Se deficiency causes inflammation of the porcine adrenal glands is still unclear. In order to study the effect of Se deficiency on the adrenal glands of pigs, we obtained Se-deficient pig adrenal glands through a low-Se diet. The results of mass spectrometry showed that the Se content in the Se-deficient group was only one-tenth of the control group. We detected the expression of the toll-like receptor 4 (TLR4) and downstream factors by qRT-PCR and Western blotting, and found that the lack of Se affected the TLR4/NF-κB pathway. It is known that miR-155-3p, miR-30d-R_1, and miR-146b have all been verified for targeting relationship with TLR4. We confirmed by qRT-PCR that miR-30d-R_1 decreased most significantly in the Se-deficient pig model. Then we tested 25 selenoproteins and some indicators of oxidative stress. It is confirmed that Se deficiency reduces the antioxidant capacity and induces oxidative stress in pig adrenal tissue. In short, a diet lacking Se induces oxidative stress in pig adrenal tissues and leads to inflammation through the miR-30d-R_1/TLR4 pathway. This study provides a reference for the prevention of adrenal inflammation in pigs from a nutritional point of view.

Protective effects of caffeic acid phenethyl ester on cadmium-induced testicular injury: A crucial role of antioxidant enzymes in male mice infertility

Infertility in men is referred to inability to achieve pregnancy in fertile females after at least one year of regular intercourse. The lack of oxygen in the environment may lead to an imbalance of testes production. Swiss mice were alienated into four groups 10 mice/each. This included one negative normal control group I. The induction of infertility was achieved with injection of cadmium chloride at dose 3 mg/kg body weight for four consecutive days for the rest groups. Group III received vehicle (saline) from the second day of induction for the similar period during the experiment. Infertile mice determined depending on alterations in morphology, motility, and reduced sperm count. Group IV was treated with 3 mg/kg of caffeic acid phenethyl ester (CAPE) per day, for 6 days from the second day of cadmium intoxication. Data showed effectiveness of CAPE significantly through improving the antioxidant enzymes SOD, GST and GSH in testes homogenate and GSH-Px in mice serum that were treated compared to those in the untreated group II (P˂0.001). The histopathology, DNA analysis showed marked improvement in spermatogenesis and DNA intact pattern in treated mice testis. Overall, the results demonstrated the ability of CAPE to improve spermatogenic cells. The data analysis indicated the possibility for the future use of CAPE as an inhibitory agent of infertility. Clinical trials and further studies are required to evaluate the definite medical effects of CAPE based on abundant experimental studies, with predictive future applications in human clinical trials.

ROS-Induced Hepatotoxicity under Cypermethrin: Involvement of the Crosstalk between Nrf2/Keap1 and NF-κB/iκB-α Pathways Regulated by Proteasome

Cypermethrin (CMN) is a man-made insecticide, and its abuse has led to potential adverse effects, particularly in sensitive populations such as aquatic organisms. The present study was focused on the toxic phenotype and detoxification mechanism in grass carp (Ctenopharyngodon idella) after treatment with waterborne CMN (0.651 μg/L) for 6 weeks in vivo or 6.392 μM for 24 h in vitro. In vivo, we describe the toxic phenotype of the liver of grass carp in terms of pathological changes, serum transaminase levels, oxidative stress indexes, and apoptosis rates. RNA-Seq analysis (2 × 3 cDNA libraries) suggested a compromise of proteasome and oxidative phosphorylation signaling pathways under CMN exposure. Thus, these two pathways were chosen for the in vitro study, which suggested that the CMN intoxication-induced proteasome pathway caused hepatotoxicity in the liver cell line of grass carp (L8824 cells). Moreover, pretreatment with MG132, a proteasome inhibitor, displayed protection against the toxic effects of CMN by enhancing antioxidative and anti-inflammatory capability by directly inhibiting the proteasomal degradation of nuclear factor erythroid-2 related factor (Nrf2) and IκB-α, thus turning on the transcription of downstream genes of Nrf2 and NF-κB, respectively. Taken together, these results suggest proteasome activity as a reason for CMN-induced hepatotoxicity.

Cadmium induces endoplasmic reticulum stress-mediated apoptosis in pig pancreas via the increase of Th1 cells

Cadmium (Cd), an environmental pollutant, causes several adverse reactions in animals. High dose of Cd has serious cytotoxicities, including the induction of programmed cell necrosis, autophagy and apoptosis, which has aroused wide public concern. The balance of cytokine network is affected by Th1/Th2 balance which is closely related to immune response and the occurrence, development, treatment and outcome of various diseases. Cd can induce severe apoptosis, but the relationship between Cd induced apoptosis and Th1/Th2 balance has not been clarified. In this study, we established a pig Cd poisoning model, exposing to CdCl₂ for 40 days (20 mg Cd/kg diet). Firstly, deviation of Th1/Th2 balance was observed by fluorescence staining, and apoptosis was observed by TUNEL staining. Then, real-time fluorescence quantitative analysis and Western blot were used to detect the expression of related proteins. The results show that Cd can interfere with the balance of Th1/Th2 and shift the balance towards Th1. In addition, through the experiments, we found that Cd exposure can increase the expression of glucose-regulated protein 94 (GRP94) and glucose-regulated protein 78 (GRP78), marker proteins of unfolded protein response (UPR). Cd exposure can increase the expression of pancreatic endoplasmic reticulum kinase (PERK), CCAAT-enhancer-binding protein homologous protein (CHOP), inositol-requiring enzyme 1 (IRE-1), activating transcription factor 6 (ATF-6), cysteinyl aspartate specific proteinase (Caspase12), indicating the three branches (ATF6, PERK and IRE-1) of endoplasmic reticulum stress (ER-stress) were activated. Moreover, we found that the expression of pro-apoptosis genes in the downstream pathway of ER-stress increased. In summary, our results indicated that Cd exposure upregulated the expression of pro-apoptosis related genes and caused apoptosis via the activation of the ER-stress signaling pathways in pancreas cells. And these negative effects were correlated with the equilibrium drift of Th1/Th2, increase in the expression and secretion of Th1 cytokines.

Environmentally relevant concentration of sulfamethoxazole-induced oxidative stress-cascaded damages in the intestine of grass carp and the therapeutic application of exogenous lycopene

Due to the unreasonable use and discharge of the aquaculture industry, over standard of the antibiotics has been frequent in different types of water environments, causing adverse effects on aquatic organisms. Lycopene (LYC) is an esculent carotenoid, which is considered to be a strong antioxidant. This study was designed to explore the therapeutic effect of LYC on antibiotic (sulfamethoxazole (SMZ)) induced intestinal injury in grass carp Ctenopharyngodon idella. The 120 carps (the control, LYC, SMZ, and co-administration groups) were treated for 30 days. We found that treatment with LYC significantly suppressed SMZ-induced intestinal epithelial cell damage and tight junction protein destruction through histopathological observation, transmission electron microscopy and detection of related genes (Claudin-1/3/4, Occludin and zonula occludens (ZO)-1/2). Furthermore, LYC mitigated SMZ-induced dysregulation of oxidative stress markers, including elevated malondialdehyde (MDA) levels, and consumed super oxide dimutese (SOD), catalase (CAT) activities and glutathione (GSH) content. In the same treatment, LYC reduced inflammation and apoptosis by a detectable change in pro-inflammatory factors (tumor necrosis factor-alpha (TNF-β), interleukin (IL)-1β, IL-6 and IL-8), anti-inflammatory factors (transforming growth factor-beta (TGF-β) and IL-10) and pro-apoptosis related genes (p53, p53 upregulated modulator of apoptosis (PUMA), Bax/Bcl-2 ratio, caspase-3/9). In addition, activation of autophagy (as indicated by increased autophagy-related genes through AMPK/ATK/MTOR signaling pathway) under the stress of SMZ was also dropped back to the original levels by LYC co-administration. Collectively, our findings identified that LYC can serve as a protectant agent against SMZ-induced intestinal injury.

Cadmium-induced Oxidative Stress and Immunosuppression Mediated Mitochondrial Apoptosis via JNK-FoxO3a-PUMA pathway in Common Carp (Cyprinus carpio L.) Gills

Cadmium (Cd)-caused water environment pollution has become a matter of concern. Gill is an organ with respiratory and mucosal immune functions, and is also one of the organs directly attacked by pollutants. It was found that excess Cd could cause Cd accumulation and gill injury in carp. However, the mechanism of Cd-caused damage in common carp gills is still unclear. Oxidative stress, immunosuppression, and apoptosis took part in the mechanism of poisoning caused by some harmful substances. The aim of the study was to investigate complex molecular mechanism of apoptotic injury caused by Cd in common carp gills. Hence, in this study, we established a Cd poisoning model to explore whether excess Cd can induce apoptosis through observing histomorphology and apoptotic cells; and determining mineral elements, oxidative stress-related factors, immune-related, and apoptosis-related genes in common carp gills. Fifty-four fish were randomly separated into the control group and the Cd group and were cultured for 45 days. The water of the control group was drinking water and the water of the Cd group was CdCl₂-added drinking water (0.26 mg/L Cd). In our results, we found that excess Cd increased Cd level, decreased the levels of essential mineral elements (Cu, Fe, Zn, and Mn), damaged mitochondria, and increased apoptotic cells in common carp gills, meaning that excess Cd caused Cd accumulation and apoptotic injury via mitochondrion in common carp gills. Furthermore, we found that Cd inhibited anti-apoptosis-related gene Bcl-2 and stimulated pro-apoptosis-related genes (JNK, FoxO3a, PUMA, Bax, Apaf-1, Caspase-9, and Caspase-3) on 15th, 30th, and 45th days. Above data meant that Cd exposure caused apoptosis via mitochondrion and JNK-FoxO3a-PUMA pathway in common carp gills. In addition, in our experiment, Cd treatment increased oxidants (H₂O₂ and MDA) and decreased antioxidants (CAT, GPx, GST, SOD, T-AOC, and GSH), indicating that Cd caused oxidative stress via oxidation/antioxidation imbalance. Meanwhile, compared to the control group, T-help 17 (Th17) cell-related factors (IL-17, TNF-α, and RORγ) were up-regulated, regulatory T (Treg) cell-related factors (IL-10 and Foxp3) were down-regulated, and IL-17/IL-10, TNF-α/IL-10, and RORγ/Foxp3 were increased in Cd-exposed group; meaning that excess Cd induced immunosuppression via the imbalance of Th17/Treg cells. Taken together, our findings indicated that JNK-FoxO3a-PUMA pathway and mitochondrion participated in oxidative stress and immunosuppression-mediated apoptosis caused by Cd in common carp (Cyprinus carpio L.) gills. Our data provided new perspectives on the negative effects of heavy metal pollutants on fish.

The Alleviative Effects of Quercetin on Cadmium-Induced Necroptosis via Inhibition ROS/iNOS/NF-κB Pathway in the Chicken Brain

Cadmium (Cd), a ubiquitous environmental pollutant, has neurotoxicity to humans and animals. Quercetin (QE), the main component of flavonoids, has strong antioxidant and anti-inflammatory effects. However, little is reported about the influence of Cd exposure on necroptosis in the chicken brain and the antagonistic impacts of QE against Cd-induced brain necroptosis. The aim of this study was to ascertain the alleviative mechanism of QE on Cd-induced necroptosis in the chicken brain. Two hundred 3.5-month-old Isa hens were randomly divided into four groups, control group, QE group, Cd group, and Cd + QE co-administration group. The histopathological analysis indicated that necrosis features were observed in the Cd-intoxicated chicken brains. Meanwhile, the expression levels of RIPK1, RIPK3, and MLKL were elevated and the level of Caspase 8 was reduced in the Cd group, which further testified Cd triggered the occurrence of necroptosis in the chicken brain. Cd exposure obviously increased Cd accumulation, ROS generation, and MDA level; weakened the activities of antioxidase (SOD, GPx, and CAT); enhanced iNOS activity and NO production; promoted the expression of inflammatory factors (NF-κB, TNFα, COX-2, iNOS, PTGEs, and IL-1β); and activated HSPs (HSP27, HSP40, HSP60, HSP70, and HSP90). But, these Cd-caused variations were obviously attenuated in the Cd + QE group. This study indicated that QE had an alleviative effect on Cd-induced necroptosis in the chicken brain through inhibition ROS/iNOS/NF-κB pathway.

NLRP3 inflammasome mediated pyroptosis is involved in cadmium exposure-induced neuroinflammation through the IL-1β/IkB-α-NF-κB-NLRP3 feedback loop in swine

Cadmium (Cd) chloride, as widely distributed toxic environmental pollutants by using in industry, severely imperils animal and human health. Pyroptosis is a Cas1-dependent pro-inflammatory programmed cell death and involves in various types of diseases. Nevertheless, the mechanism of pyroptosis and Cd-induced neurotoxicity remains obscure. To investigate the specific molecular mechanisms of Cd-induced neurotoxicity, 10 weaned piglets were randomly divided into 2 groups treated with 0 and 20 mg/kg CdCl₂ in the diet for 40 days. The levels of pyroptosis, mitochondrial and inflammation-related genes were validated by qRT-PCR and WB in vivo. Our results revealed that Cd caused cerebral histopathology lesions, inducing cerebral pyroptosis and the mass generation of inflammatory cytokines, as indicated by the increased NLRP3 inflammasome activation (NLRP3, Cas1 and ASC) and the upregulation of inflammation factors IL-2, IL-6, IL-7 and inhibition of IL-10. Subsequently, further research indicated that Cd triggered pyroptosis via activating the TRAF6-IkB-α-NF-κB pathway, which interfered with the phosphorylation and ubiquitination of IkB-α. Furthermore, Cd caused mitochondrial dysfunction and fragmentation by inhibiting the AMPK-PGC-1α-NRF1/2 signaling pathway and reduced the expression of mitochondrial-related regulatory factors OPA1, TFAM and mtDNA, resulting in the increase of NLRP3 inflammasome. Besides, we found eight hub genes (IKK, IKB-α, NLRP3, TRAF6, NF-κB, AMPK, TNFα and PGC-1α), mainly related to the interaction between the NF-κB pathway and NLRP3 inflammasome. Overall, these results demonstrated that Cd could promote the IL-1β/IkB-α-NF-κB-NLRP3 inflammasome activation positive feedback loop to result in neuroinflammation in swine, which provided new insights in understanding Cd-induced toxicity.