Whole transcriptome-based miRNA-mRNA network analysis revealed the mechanism of inflammation-immunosuppressive damage caused by cadmium in common carp spleens

Histology and transcriptomic analysis reveal the inflammation and affected pathways under 2-methylisoborneol (2-MIB) exposure on grass carp

2-Methylisoborneol (2-MIB) is a common and widely distributed off-flavor compound in water. However, the toxic mechanisms of 2-MIB on aquatic organisms remain largely unexplored. In this study, grass carp larvae were exposed to different concentrations (0, 5, and 20 μg L-1) of 2-MIB for 96 h. The accumulation of 2-MIB in the dorsal muscle was measured. Histological analysis, ultrastructure observations, and transcriptomic sequencing were conducted on the liver tissues. The results showed that 2-MIB accumulated significantly in the fish muscle, with the accumulation increasing as the exposure concentration increased through gas chromatography-mass spectrometry (GC-MS) detection. Histological and ultrastructure observations indicated that 2-MIB caused concentration-dependent inflammatory infiltration and mitochondrial damage in the liver. Transcriptomic analysis revealed lipid metabolism disorders induced by exposure to 2-MIB in grass carp. Additionally, 5 μg L-1 2-MIB affected the neurodevelopment and cardiovascular system of grass carp larvae through extracellular matrix (ECM)-receptor interaction and focal adhesion pathway. Furthermore, several pathways related to the digestive system were significantly enriched, implying that 2-MIB may impact pancreatic secretion function, protein digestion and absorption processes. These findings provide new insights into the potential toxicological mechanisms of 2-MIB.

Probiotics in addressing heavy metal toxicities in fish farming: Current progress and perspective

Heavy metal contamination of aquatic environments adversely affects the health of aquatic organisms and consumption of fish contaminated with heavy metals poses serious health risks to humans. Among various strategies, probiotics (living microorganisms known to have beneficial effects on the host), which have been extensively applied in the aquaculture industry, could be helpful for heavy metal detoxification and remediation. Several probiotics, including Lactobacillus strains, exhibit heavy metal binding, high heavy metal tolerance, and other beneficial characteristics for the host. Notably, numerous probiotics have been reported to bind heavy metals and excrete them from the host. Various probiotic strains (Lactobacillus, Bacillus, Lactococcus, etc.) show beneficial effects in alleviating heavy metal toxicity in cultured fish species. Certain probiotic bacteria reduce the absorption and bioavailability of heavy metals by enhancing heavy metal detoxification and sequestration while preserving gut barrier function. This review summarises the toxic effects of selected heavy metals on the health of farmed fish and discusses the role of probiotic strains in remediating the consequential exposure-induced immune toxicity and oxidative stress. Moreover, we discussed the protective strategies of probiotics against heavy metal accumulation in various tissues and gut dysbiosis in fish to alleviate heavy metal toxicity in fish farming, thereby promoting a sustainable blue economy worldwide.

Cadmium promoted LPS-induced inflammation through TLR4/IκBα/NFκ-B signaling by increasing ROS-mediated incomplete autophagy

Cadmium (Cd) exposure is considered as non-infectious stressor to human and animal health. Recent studies suggest that the immunotoxicity of low dose Cd is not directly apparent, but disrupts the immune responses when infected with some bacteria or virus. But how Cd alters the adaptive immunity organ and cells remains unclear. In this study, we applied lipopolysaccharide (LPS, infectious stressor) to induced inflammation in spleen tissues and T cells, and investigated the effects after Cd exposure and the underlying mechanism. Cd exposure promoted LPS-induced the expressions of the inflammatory factors, induced abnormal initiation of autophagy, but blocked autophagic flux. The effects Cd exposure under LPS activation were reversed by the autophagy promoter Rapamycin. Under LPS activation conditions, Cd also induced oxidative stress by increasing the levels of reactive oxygen species (ROS) and malondialdehyde (MDA), and reducing total antioxidant capacity (T-AOC) activity. The increased superoxide dismutase (SOD) activity after Cd exposure might be a negative feedback or passive adaptive regulation of oxidative stress. Cd-increased autophagic flux inhibition and TNF-α expression were reversed by ROS scavenger α-tocopherol (TCP). Furthermore, under LPS activation condition, Cd promoted activation of toll-like receptor 4 (TLR4)/IκBα/NFκ-B signaling pathway and increased TLR4 protein stability, which were abolished by the pretreatment of Rapamycin. The present study confirmed that, by increasing ROS-mediated inhibiting autophagic degradation of TLR4, Cd promoted LPS-induced inflammation in spleen T cells. This study identified the mechanism of autophagy in Cd-aggravated immunotoxicity under infectious stress, which could arouse public attention to synergistic toxicity of Cd and bacterial or virus infection.

Baicalin Relieves Airway Inflammation in COPD by Inhibiting miR-125a

To investigate the effects of Baicalin on the apoptosis of human bronchial epithelial cells (16HBE) induced by cigarette smoke extract (CSE) and the release of inflammatory factors, and to clarify its possible mechanism. CSE was used to treat 16HBE cells and construct COPD cell model. The activity of 16HBE cells was detected by CCK-8 and BrdU. Real-time fluorescence quantitative PCR (RT-QPCR) was used to detect the expression level of miR-125a in each group of 16HBE cells. At the same time, the levels of 16HBE inflammatory cytokines IL-1β, IL-8, IL-6, and TNF-α were detected. The apoptosis rate of 16HBE cells in each group was detected by TUNEL. Compared with the control group, the proliferation of 16HBE cells in CSE group was decreased. Baicalin reversed the effect of 2% CSE on the proliferation of 16HBE cells. Baicalin also reversed the effect of 2% CSE on apoptosis and inflammatory factors in 16HBE cells. miR-125a is highly expressed in COPD, and Baicalin can inhibit the expression of miR-125a. Silencing miR-125a reduces apoptosis and inflammatory response of 16HBE cells in COPD. miR-125a reversed the effects of Baicalin on apoptosis and inflammation of 16HBE cells. Baicalin can reduce CSE-induced apoptosis of human bronchial epithelial cells and release of inflammatory factors, and its mechanism may be related to the inhibition of miR-125a.

MicroRNA-30e-3p regulates the inflammatory response by targeting the gimap8 gene in Ctenopharyngodon idella kidney (CIK) cells

Recent studies have increasingly linked miRNAs with the modulation of inflammatory responses and immunosuppressive activities. This investigation reveals that mir-30e-3p selectively binds to and modulates gimap8, as demonstrated by luciferase reporter assays and qPCR analyses. Upon LPS stimulation of CIK cells, mir-30e-3p expression was notably elevated, inversely correlating with a decrease in gimap8 mRNA levels. Overexpression of mir-30e-3p attenuated the mRNA levels of pro-inflammatory cytokines beyond the effect of LPS alone, suggesting a regulatory role of mir-30e-3p in inflammation mediated by the gimap8 gene. These insights contribute to our understanding of the complex mechanisms governing inflammatory and immune responses.

Glycyrrhiza Extract and Curcumin Alleviates the Toxicity of Cadmium via Improving the Antioxidant and Immune Functions of Black Goats

To investigate the mitigative effects of glycyrrhiza extract (GE) and curcumin (CUR) on the antioxidant and immune functions of the Guizhou black goat exposed to cadmium (Cd), 50 healthy Guizhou black goats (11.08 ± 0.22 kg, male, six months old) were used in a 60-day trial and were randomly assigned to five groups with 10 replicates per group, one goat per replicate. All goats were fed a basal diet, with drinking water and additives varying slightly between groups. Control group: tap water (0.56 μg·L-1 Cd); Cd group: drinking water containing Cd (20 mg Cd·kg-1·body weight, CdCl2·2.5H2O); GE group: drinking water containing Cd, at days 31 to 60, the basic diet had added 500 mg·kg-1 GE; CUR group: drinking water containing Cd, at days 31 to 60, the basic diet had added 500 mg·kg-1 CUR; combined group: drinking water containing Cd, at days 31 to 60, the basic diet had added 500 mg·kg-1 GE and CUR. Compared with the Cd group, GE and CUR significantly increased the levels of hemoglobin and red blood cell count in the blood, and the activities of serum antioxidant enzyme activity and immune function in the Guizhou black goat (p < 0.05). The treatment effect in the combined group was better than that in the GE and CUR groups. The results showed that GE and CUR improved the antioxidant and immune functions of the serum and livers of the Guizhou black goat and alleviated the toxicity damage of Cd contamination. This research has positive implications for both livestock management and human health.

An integrative data-centric approach to derivation and characterization of an adverse outcome pathway network for cadmium-induced toxicity

Cadmium is a prominent toxic heavy metal that contaminates both terrestrial and aquatic environments. Owing to its high biological half-life and low excretion rates, cadmium causes a variety of adverse biological outcomes. Adverse outcome pathway (AOP) networks were envisioned to systematically capture toxicological information to enable risk assessment and chemical regulation. Here, we leveraged AOP-Wiki and integrated heterogeneous data from four other exposome-relevant resources to build the first AOP network relevant for inorganic cadmium-induced toxicity. From AOP-Wiki, we filtered 309 high confidence AOPs, identified 312 key events (KEs) associated with inorganic cadmium from five exposome-relevant databases using a data-centric approach, and thereafter, curated 30 cadmium relevant AOPs (cadmium-AOPs). By constructing the undirected AOP network, we identified a large connected component of 18 cadmium-AOPs. Further, we analyzed the directed network of 59 KEs and 82 key event relationships (KERs) in the largest component using graph-theoretic approaches. Subsequently, we mined published literature using artificial intelligence-based tools to provide auxiliary evidence of cadmium association for all KEs in the largest component. Finally, we performed case studies to verify the rationality of cadmium-induced toxicity in humans and aquatic species. Overall, cadmium-AOP network constructed in this study will aid ongoing research in systems toxicology and chemical exposome.

Comprehensive mRNA and microRNA analysis revealed the effect and response strategy of freshwater fish, grass carp (Ctenopharyngodon idella) under geosmin exposure

Geosmin is an environmental pollutant that causes off-flavor in water and aquatic products. The high occurrence of geosmin contamination in aquatic systems and aquaculture raises public awareness, however, few studies have investigated the response pathways of geosmin stress on freshwater fish. In this research, grass carp were exposed to 50 μg/L geosmin for 96 h, liver tissue was sequenced and validated using real-time qPCR. In total of 528 up-regulated genes and 488 down-regulated genes were observed, includes cytochrome P450 and uridine diphosphate (UDP)-glucuronosyltransferase related genes. KEGG analysis showed that chemical carcinogenesis-DNA adducts, metabolism of xenobiotics by cytochrome P450, drug metabolism-cytochrome P450 pathway was enriched. Common genes from the target genes of microRNAs and differential expression genes are enriched in metabolism of xenobiotics cytochrome P450 pathway. Two miRNAs (dre-miR-146a and miR-212-3p) down regulated their target genes (LOC127510138 and adh5, respectively) which are enriched cytochrome P450 related pathway. The results present that geosmin is genetoxic to grass carp and indicate that cytochrome P450 system and UDP-glucuronosyltransferase play essential roles in biotransformation of geosmin. MicroRNAs regulate the biotransformation of geosmin by targeting specific genes, which contributes to the development of strategies to manage its negative impacts in both natural and artificial environments.

Effects of miR-722 on gene expression and alternative splicing in the liver of half-smooth tongue sole after infection with Vibrio anguillarum

MicroRNAs play crucial roles in various biological processes, including but not limited to differentiation, development, disease, and immunity. However, their immunoregulatory roles in half-smooth tongue sole are lacking. Our previous studies indicated that miR-722 could target C5aR1 to modulate the complement pathway to alleviate inflammatory response and even affect the mortality after the bacterial infection with Vibrio anguillarum. Driven by the purpose of revealing the underlying mechanisms, in this study, we investigated the effects of miR-722 on the gene expression and alternative splicing (AS) in the liver of half-smooth tongue sole after Vibrio anguillarum infection, with the approach of miR-722 overexpression/silencing and subsequent RNA-seq. Among the different comparisons, the I group (miR-722 inhibitor and V. anguillarum) versus blank control (PBS) exhibited the highest number of differentially expressed genes (DEGs), suggesting that the immune response was overactivated after inhibiting the miR-722. In addition, enrichment analyses were performed to reveal the functions of DEGs and differential AS (DAS) genes, reflecting the enrichment of RNA splicing and immune-related pathways including NF-κB and T cell receptor signaling pathway. Comparing the M group (miR-722 mimic and V. anguillarum) with the negative control (random sequence and V. anguillarum), two immune-related genes, cd48 and mapk8, were differentially expressed, of which mapk8 was also differentially spliced, indicating their importance in the immune response. Furthermore, representative gene analysis was performed, suggesting their corresponding functional changes due to AS. To verify the RNA-seq data, quantitative real-time PCR was employed with twenty pairs of primers for DEGs and DAS events. Overall, our results demonstrated that miR-722 could mediate the transcriptome-wide changes of gene expression and AS in half-smooth tongue sole, and provided insights into the regulatory role of miR-722 in immune responses, laying the foundation for further functional analyses and practical applications in aquaculture.

The interaction between miRNAs and hazardous materials

Toxic agents are broadly present in the environment, households, and workplaces. Contamination of food and drinking water with these agents results in entry of these materials to the body. The crosstalk between these agents and microRNAs (miRNAs) affects pathoetiology of several disorders. These agents can influence the redox status, release of inflammatory cytokines and mitochondrial function. Altered expression of miRNA is involved in the dysregulation of several pathophysiological conditions and signaling pathways. These molecules are also implicated in the adaption to environmental stimuli. Thus, the interactions between miRNAs and toxic materials might participate in the hazardous effects of these materials in the body. This review describes the effects of the toxic materials on miRNAs and the consequences of these interactions on the human health.

Protective effect of quercetin on avermectin induced splenic toxicity in carp: Resistance to inflammatory response and oxidative damage

Avermectin pollution is an important problem that cannot be ignored in aquatic system in recent years. It has brought great trouble to freshwater aquaculture, especially fishery aquaculture. Plant-derived quercetin has anti-inflammatory and antioxidant properties and is widely used as a dietary additive, but its protective effect on immune damage induced by avermectin in freshwater carp remains unclear. This study evaluated the role of dietary additive quercetin supplementation in chronic avermectin exposure of carp spleen. Sixty carp were divided into 4 groups (n = 15/ group), including control group, avermectin treatment group, quercetin treatment group, quercetin and avermectin co-treatment group. Carp were exposed to a 1/10 96 h LC₅₀ dose of avermectin for 30 d and fed a carp diet containing 400 mg/kg quercetin twice a day (3% body weigh/ carp). The results showed that chronic avermectin exposure caused the loose parenchymal structure of carp spleen tissue and the increase of inflammatory cells, accompanied by increased transcription levels of pro-inflammatory il-1β, il-6, tnf-α and decreased levels of anti-inflammatory factors il-10 and tgf-β1, ROS accumulation in spleen tissue. MDA content increased and T-AOC, CAT and GSH levels decreased. Quercetin down-regulates the NF-κB pathway by inhibiting the expression of iNOS and activating p38 MAPK, blocking the transcription of inflammatory factors, and alleviating the inflammation of carp spleen caused by chronic avermectin exposure. In addition, quercetin inhibits the over-activation of Nrf2/Keap-1 signaling axis, blocks ROS accumulation, and restores the spleen REDOX homeostasis. In conclusion, quercetin, as a dietary additive for carp feed, can effectively improve the immune damage caused by avermectin pollution in aquatic environment, resist spleen inflammation and oxidative stress, and provide a theoretical basis for clinical development of freshwater carp feed.

Cadmium exposure caused cardiotoxicity in common carps (Cyprinus carpio L.): miR-9-5p, oxidative stress, energetic impairment, mitochondrial division/fusion imbalance, inflammation, and autophagy

Cadmium (Cd), a toxic heavy metal pollutant, is a threat to human and eatable fish health. Common carps are widely cultivated and eaten by humans. However, there are no reports about Cd-damaged common carp hearts. Our experiment attempted to investigate the cardiotoxicity of Cd to common carps by establishing a common carp Cd exposure model. Our results showed that Cd injured hearts. Moreover, Cd treatment induced autophagy via miR-9-5p/Sirt1/mTOR/ULK1 pathway. Cd exposure caused oxidant/antioxidant imbalance and oxidative stress; and led to energetic impairment. Energetic impairment partook in oxidative stress-mediated autophagy through AMPK/mTOR/ULK1 pathway. Furthermore, Cd caused mitochondrial division/fusion imbalance and resulted in inflammatory injury via NF-κB-COX-2-PTGEs and NF-κB-COX-2-TNF-α pathways. Oxidative stress mediated mitochondrial division/fusion imbalance, further induced inflammation and autophagy via OPA1/NF-κB-COX-2-TNF-α-Beclin1 and OPA1/NF-κB-COX-2-TNF-α/P62 pathways under Cd treatment. Taken together, miR-9-5p, oxidative stress, energetic impairment, mitochondrial division/fusion imbalance, inflammation, and autophagy participated in the mechanism of Cd-cardiotoxicity to common carps. Our study revealed harmful effect of Cd on hearts, and provided new information for researches of environmental pollutant toxicity.

Cadmium induced bioaccumulation, histopathology, gene regulation in fish and its amelioration - A review

Different anthropogenic activities as well as natural sources contribute enormously towards various heavy metal contaminations in aquatic habitats. Cadmium (Cd) is one of most prevalent and toxic heavy metals with a long half life. Unlike terrestrial animals, exposure of Cd in fishes may happen not only through feeds but also from its habitat water. Bioaccumulation of Cd in fishes occurs in many tissues, but mainly in gill, liver, kidney, skin, and muscle. The concentrations of Cd in fish tissues depend upon the extent and duration of Cd exposure, species and age of fishes, dietary minerals and antioxidant concentrations, and habitat water quality. Specific histopathological observations in liver, kidney, and gill are useful to understand the effects of Cd, which could help to determine the ameliorating methods to be adopted. Exposure of Cd exerts several adverse effects on general growth and development, reproductive processes, osmoregulation, morphological and histological structures, stress tolerance, and endocrine system, mainly due to changes in biological functions induced by differential expressions of several genes related to oxidative stress, apoptosis, inflammation, immunosuppressions, genotoxicity, Cd chelation and carbohydrate metabolism. Chronic biomagnifications of Cd exceeding the permitted level may be harmful not only to the fishes itself but also to humans through food chains. Amelioration of such toxic heavy metal that has been categorized as a potent carcinogenic in humans is of utmost importance. Main modes of amelioration encompas reducing oxidative damages by promoting the antioxidative defenses, decreasing Cd absorption, increasing excretion through excretory system and improving the tolerance of fishes to Cd toxicity. Many amelioration measures such as use of minerals (for example, zinc, calcium, and iron), vitamins (vitamin C, A, and E), different herbs, probiotics and other agents (taurine, bentonite, chitosan, zeolite, and metallothionein) have been explored for their effective roles to reduce Cd bioaccumulation and toxicity symptoms in fishes. The present review discusses bioaccumulation of Cd, histopathological alterations, oxidative stress, synergism-antagonism, and gene regulation in different tissues, and its amelioration measures in fishes.

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.

Cadmium induced immunosuppression through TLR-IκBα-NFκB signaling by promoting autophagic degradation

Environmental and occupational exposure to cadmium (Cd) poses a serious threat to human health. Recent studies indicate that Cd perturbs the immune system and increases the risk of pathogenicity and mortality of bacterial or virus infection. However, the underlying mechanism of Cd-modulated immune responses remains unclear. In this study, we aim to investigate the role of Cd in the immune function of mouse spleen tissues and its primary T cells with Concanavalin A (ConA, a well-known T cell mitogen) activation condition, and elucidate the molecular mechanism. The results showed that Cd exposure inhibited ConA-induced the expressions of tumor necrosis factor alpha (TNF-α) and interferon gamma (IFN-γ) in mouse spleen tissues. Furthermore, the transcriptomic profile by RNA-sequence reveals that: (1) Cd exposure can alter immune system process; (2) Cd may affect the NFκB signaling pathway. Both in vitro and in vivo results showed that Cd exposure reduced ConA-activated toll-like receptor 9 (TLR9)-IκBα-NFκB signaling, and the expressions of TLR9, TNF-α and IFN-γ, which were effectively reversed by autophagy-lysosomal inhibitors. All these results confirmedly demonstrated that, by promoting the autophagy-lysosomal degradation of TLR9, Cd suppressed immune response under ConA activation condition. This study provides insight on the mechanism of Cd immunnotoxicity, which might contribute to the prevention of Cd toxicity in the future.

Molybdenum fertilizer improved antioxidant capacity of Chinese Merino sheep under compound contamination

To investigate the response of different levels of molybdenum (Mo) fertilizer to Chinese Merino sheep (Junken Type) grazing on natural heavy metal-contaminated meadows, this study was carried out in the Bayanbulak Grassland lying in the northwest of Xinjiang Uygur Autonomous Region, China. A total of 24-hm2 polluted meadows were fenced and were randomly divided into four groups (3 replication/group and 2 hm2/replication) applied 0-kg Mo, 1-kg Mo, 2-kg Mo, and 3-kg Mo (ammonium molybdate tetrahydrate) per hectare for the CON group, group I, group II, and group III, respectively. Seventy-two healthy 1-year-old Chinese Merino sheep (45.56 ± 2.35 kg) were randomly assigned to the tested pastures for 90 days. Compared with the CON group, the Mo content from fertilized groups and the Se content from group II and group III in serums and livers were significantly increased (P < 0.05), and the Cu content from fertilized groups in serums and livers was significantly decreased (P < 0.05). The levels of blood Hb and RBC, and the activities of serum SOD, CAT, GSH-Px, and Cp in group III, were significantly higher (P < 0.05) than those in the CON group, group I, and group II. Serum MDA content in group III was significantly lower (P < 0.05) than that in the other three groups. In summary, Mo fertilization improved the antioxidant capacity of grazing sheep and also reduced the toxic damage to Chinese Merino sheep grazing on natural grasslands contaminated by heavy metals, but Mo poisoning caused by excessive fertilization should be prevented.

EGCG alleviated Mn exposure-caused carp kidney damage via trpm2-NLRP3-TNF-α-JNK pathway: Oxidative stress, inflammation, and tight junction dysfunction

Manganese (Mn), an essential trace metal element in organisms. However, with extensive use of Mn in industry and agriculture, Mn becomes a heavy metal pollutant in water. (-)-epigallocatechin gallate (EGCG), an tea polyphenols, can alleviate metal toxicity. Kidney is an important detoxifying organ, but toxic mechanism of Mn to kidneys is unclear, which needs further research. Carp is an Asian important economical species for fisheries and a biological model for studying environmental toxicology. Thus, we established excess Mn and EGCG-supplemented carp model to explore molecular mechanism of EGCG alleviating Mn-caused carp kidney damage. In this experiment, we set a control group (the Con group), a Mn treatment group (the Mn group, 90 mg/L Mn), a EGCG supplement group (the EG group, 75 mg/kg EGCG), and a combined group (the Mn + EG group, 90 mg/L Mn and 75 mg/kg EGCG). Transcriptome, qRT-PCR, kit, and morphology method results indicated that excess Mn caused oxidative stress, inflammatory damage, and tight junction dysfunction in carp kidneys. Excess Mn-triggered oxidative stress caused tight junction dysfunction via trpm2-NLRP3-TNF-α-JNK pathway and inflammation. EGCG reversed the harm of Mn to fish through the above mechanism. The findings of this study provided the evidence of EGCG-alleviated Mn poisoning and offered new ideas for reducing heavy metal environmental pollution risk.

Cadmium contributes to atherosclerosis by affecting macrophage polarization

Chronic cadmium (Cd) exposure contributes to the progression of atherosclerosis, but the direct role of Cd and its mechanisms in atherosclerosis remains incompletely understood. Atherosclerosis is a chronic inflammatory disease promoting macrophage polarization to M1 phenotype and producing pro-inflammations that are vital in regulating the inflammatory response. Herein, through a case-control study, we found that Cd exposure may promote the occurrence of carotid plaque via inflammation, where interleukin-6 (IL-6) may play an important role. We also combined in vivo and in vitro experiments to explore the underlying mechanism of Cd-promoted plaque formation and the production of IL-6. With or without cadmium chloride (CdCl₂) fed ApoE^-/- mouse and treated RAW264.7 cells, we found Cd accumulated in the aortas which significantly increased the plaque area in atherosclerotic mice, macrophage accumulation, and lipid accumulation, and Cd promoted M1 phenotype macrophage polarization reflected by the increased expression of CD86 which produced tumor necrosis factor-α (TNF-α) and IL-6. However, the influences on M2 phenotype and anti-inflammatory cytokines interleukin-4 (IL-4) and interferon-γ (IFN-γ) were non-significant. Moreover, we found that JAK2/STAT3 pathway was greatly activated in the plaques and CdCl₂-treated macrophages. The inhibition of JAK2/STAT3 substantially reversed the Cd-stimulated macrophage M1 phenotype macrophage polarization and the expression of pro-inflammatory cytokines including TNF-α and IL-6. Altogether, Cd intensifies atherosclerosis by modulating macrophage polarization via JAK2/STAT3 to up-regulated the expression of IL-6.

Integration of microRNA and mRNA analyses depicts the potential roles of Momordica charantia saponin administration in insulin resistance of juvenile common carp (Cyprinus carpio) fed with a high-starch diet

Background: The regulation of target gene mRNA mediated by microRNA may play an important role in glucose metabolism in fish. Previous research findings of our research group revealed that Momordica charantia saponin (MS) administration in a high-starch diet could improve insulin resistance of common carp through renovating insulin signaling pathways, whose fundamental mechanisms have remained unknown by far. To reveal this potential mechanism, we aimed to investigate the difference in miRNA and mRNA expression profiles between common carp fed with high-starch diets containing MS (HS_MS1 and HS_MS2) and common carp fed with high-starch (HS) diets. Results: Through miRNA deep-sequencing, 10 significantly differentially expressed miRNAs in HC and HS_MS1, including one upregulated and nine downregulated miRNAs, were identified, whereas 10 significantly differentially expressed miRNAs in HC and HS_MS2, including four upregulated and six downregulated miRNAs, were identified. These miRNAs may not only be involved in the regulation of insulin signaling pathways and insulin resistance in common carp but also be the markers for liver insulin resistance in MS therapy for the remission of insulin resistance. This study identified 10 potential known miRNAs, namely, ccr-miR-10b, ccr-miR-122, ccr-miR-143, ccr-miR-146a, ccr-miR-155, ccr-miR-16c, ccr-miR-200a, ccr-miR-29a, ccr-miR-34, and ccr-miR-375, as candidates participating in modulating the liver insulin resistance. According to the biopathway enrichment analysis of the 252 target genes using the KEGG classical biopathway database, the relative expression levels of gsk3bb, pik3r1, and pik3r3b were analyzed using RNA-seq. Compared to the HC group, a significant decrease in the relative expression levels of pik3r1 and pik3r3b was observed in HS_MS1 and HS_MS2 groups (p < 0.05). This study raised a presumption of the presence of ccr-miR-29a targeting pik3r1 or ccr-miR-143 targeting pik3r3 playing likely roles in Momordica charantia saponins remitting the liver insulin resistance. Conclusion: The findings will further deepen the understanding of the carbohydrate metabolism of common carp and provide an important scientific basis for the application of Momordica saponins as functional nutrients to alleviate insulin resistance of fish in fish culture.

Deciphering sex-specific miRNAs as heat-recorders in zebrafish

In the last decade, a plethora of microRNAs (miRNAs) has been reported in a wide variety of physiological processes, including reproduction, in many aquatic organisms. However, miRNAome alterations occurred by environmental cues due to water temperature increment have not yet been elucidated. With the aim to identify epigenetic regulations mediated by miRNAs in the gonads in a climate change scenario, the animal model zebrafish (Danio rerio) were subjected to high temperatures during sex differentiation, a treatment that results in male-skewed sex ratios in the adulthood. Once the fish reached adulthood, gonads were sequenced by high-throughput technologies and a total of 23 and 1 differentially expressed miRNAs in ovaries and testes, respectively, were identified two months after the heat treatment. Most of these heat-recorder miRNAs were involved in human sex-related cancer and about 400 predicted-target genes were obtained, some with reproduction-related functions. Their synteny in the zebrafish genome was, for more than half of the predicted target genes, in the chromosomes 7, 2, 4, 3 and 11 in the ovaries, chromosome 4 being the place where the sex-associated-region (sar) is localized in wild zebrafish. Further, spatial localization in the gonads of two selected heat-recorder miRNAs (miR-122-5p and miR-146-5p) showed exclusive expression in the ovarian germ cells. The present study expands the catalog of sex-specific miRNAs and deciphers, for the first time, thermosensitive miRNAs in the zebrafish gonads that might be used as potential epimarkers to predict environmental past events.

Condensed Tannins Improved Immune Functions and Reduced Environmental Pollution of Captive Sichuan Black Goat Kids Under Cadmium Toxicity

To investigate the effects of condensed tannins (CT) on immune functions and nitrogen (N) emissions of captive Sichuan black goat kids under cadmium (Cd) toxicity, a total of 18 Sichuan black goat kids (2 months old, 9.6 ± 1.2 kg) were randomly used in this 30-day trial. The dietary treatments were (1) CON group, basic diet; (2) Cd group, basic diet + oral 10 mg Cd/kg·BW; and (3) CT group, Cd group + 400 mg/kg CT. Oral Cd supplementation significantly decreased the Cu and Fe contents in serums and livers of captive Sichuan black goat kids (P < 0.05), but adding CT in the Cd group increased the Fe and Mo contents and decreased the Cd content in serums and livers (P < 0.05). Additional CT supplementation in the Cd group extremely increased the activities of serum SOD, GSH-Px, and CAT (P < 0.05), and greatly decreased the serum MDA content (P < 0.05). The CT supplementation in the Cd group also extremely increased the concentrations of serum IgG, IgM, and IgA (P < 0.05), and greatly decreased the contents of IL-6, IL-1β, and TNF-α in serums (P < 0.05). Adding CT in the Cd group significantly increased the apparent digestibility of CP and EE and decreased the urinary nitrogen (UN) content (P < 0.05, Table 7). In conclusion, the application of additional CT improved antioxidant capacities and immune functions of captive black goats under Cd toxicity, then reduced the oxidative stress and toxic damage of Cd contamination. CT also improved the N digestibility and reduced the N emission, which was helpful to reduce environmental pollution.

The Role of PTEN/PI3K/AKT Signaling Pathway in Apoptosis of Liver Cells in Cocks with Manganese Toxicity

PTEN/PI3K/AKT signaling pathway is an important pathway for cell proliferation and apoptosis. Exposure to excess manganese (Mn) can cause damage in organisms. However, whether Mn toxicity can cause apoptosis is still not clear. In order to explore the mechanism of PTEN/PI3K/AKT signaling pathway responsible for Mn-induced apoptotic injury, 160 Hyline cocks were divided into four groups; there were the control group (Con group), the low-dose Mn group (L group), the medium-dose Mn group (M group), and the high-dose Mn group (H group). The cocks in Con group, L group, M group, and H group were fed with MnCl₂ diet containing 100, 600, 900, and 1800 mg/kg, respectively. The growth status of cocks in each group was observed on days 30, 60, and 90. Thirty cocks were randomly selected from each group and sacrificed on day 90 for optical microscope observation and fluorescence microscopic observation, as well as for transcription-level expression of apoptosis-related genes and heat shock proteins (HSPs) in the liver. The results showed that the growth status of cocks was gradually depressed with the extension of feeding time and with the increase of Mn dose_. On day 90, the results of optical microscope observation and fluorescence microscope observation showed that damage and apoptosis appeared in the cock liver cells under Mn exposure groups. The results of transcription-level detection of apoptosis-related genes and HSPs indicated that Mn exposure upregulated eleven pro-apoptotic genes (including RIP1, RIP3, MLKL, Bax, Caspase-3, FADD, Cyt-C, ERK, JNK, Caspase-8, and P38) and downregulated one anti-apoptotic gene Bcl-2, further meaning that exposure to Mn-induced apoptosis in cock liver cells and PTEN/PI3K/AKT signaling pathway took part in molecular mechanism of apoptosis caused by excess Mn. Moreover, in our experiment, the increase of four HSPs (including HSP27, HSP40, HSP60, and HSP70) was found after Mn treatment for 90 days, which indicated that Mn stress triggered HSPs and HSPs were involved in molecular mechanism of Mn poisoning in cock livers. In addition, we also found there was upregulated dose-dependent manner in fifteen detected genes and there was downregulated dose-dependent manner in Bcl-2, indicating that the apoptosis caused by Mn poisoning in cock liver cells was dose-dependent.

Role of miR-451 in mediating cadmium induced head kidney injury in common carp via targeting cacna1ab through autophagy pathways

Cadmium (Cd) is a common environmental pollutant, which leads to Cd residue in aquatic animals. The Cd in aquatic animals will be enriched into the human body through the food chain and seriously harm human health. The research aims to investigate the molecular mechanism of Cd poisoning in common carps. Our previous studies have confirmed that 23 differentially expressed miRNAs were potential biomarkers for Cd exposure in common carp head kidney lymphocytes. Herein, based on the prediction of the website and previous studies, miR-451 and cacna1ab were selected and their targeting relationship was verified again by dual-luciferase. Subsequently, we established the miR-451 overexpression/knockdown models and miR-451 inhibitor, cacna1ab co-knockdown models in common carp head kidney lymphocytes respectively. Immunofluorescence staining, MDC staining, calcium staining, qRT-PCR (Quantitative Real-time PCR) and western blot were used to detect the levels of autophagy. Our results demonstrated that Cd significantly decreased the expression of miR-451, miR-451 suppression thereby induced increased cacna1ab and the expression of ATG5, LC3-I, LC3-II and Beclin 1, while significantly inhibiting the expression of mTOR, P62 and Bcl-2, which indicated that autophagy was triggered. Moreover, the miR-451 knockdown group activated the expression of autophagy related factors as well as the Cd group. However, cacna1ab knockdown can reduce autophagy activation induced by miR-451 knockdown. Our results indicated that Cd induced autophagy in head kidney lymphocytes through the inhibition of miR-451 and the excitation of cacna1ab.

Effect of mild intermittent cold stimulation on thymus immune function in broilers

This study aims to assess the effect of intermittent and mild cold stimulation (IMCS) on thymus function and the ability of 1-day-old male Ross 308 broilers to withstand cold. Four hundred broilers were reared under normal and mild cold temperatures at 3°C below the normal feeding temperature and were subjected to acute cold stress (ACS) at 10°C on d 50 at 7 am for 6 h, 12 h, and 24 h. We determined the expression levels of toll-like receptors (TLRs), cytokines and avian β-defencins (AvBDs), encoding genes in thymus of broilers at 22, 36, 43, and 50 d of age, and the serum ACTH and cortisol (CORT) levels at 50 d of age. At D22 and D36, the mRNA expression levels of TLRs and AvBDs genes in CS groups were generally significantly decreased (P < 0.05). The lowest expression levels were found in birds submitted to intermittent and mild cold stimulation training for 5 h (CS5 group) on d 22 and 36 of development (P < 0.05). At D43 and D49 after IMCS, mRNA expression levels of most TLRs and AvBDs were significantly lower than those in CC group (P < 0.05), and that mRNA expression levels of all TLRs and most AvBDs in CS5 group had the same change trend with age as those in CC group (P > 0.05). At D22 and D36, mRNA expression levels of different cytokines in each CS groups were different (P < 0.05). mRNA expression levels of IL-2, IL-4, IL-6, IL-8, IL-17, and IFN-α all reached the highest values in the CS5 group at D36 (P < 0.05). The levels of ACTH and CORT in all IMCS-treated birds changed in varying degrees after ACS, but there was no significant change in CS5 group (P > 0.05). Collectively, different cold stimulation schemes could modulate thymus immune function of broilers by maintaining homeostasis and enhancing cold resistance. In particular, the optimal cold adaptation scheme was at 3°C below the conventional feeding temperature for 5 h.

Genome-wide identification of chicken bursae of Fabricius miRNAs in response to very virulent infectious bursal disease virus

Infectious bursal disease virus (IBDV) can cause a highly contagious immunosuppressive disease in young chickens. MicroRNAs (miRNAs) are crucial regulators of gene expression and are involved in the pathogenesis of IBDV infection. To investigate the roles of miRNA in chicken bursae of Fabricius in response to very virulent IBDV (vvIBDV) infection, RNA sequencing was performed to compare the small RNA libraries from uninfected and vvIBDV-infected group which was infected for 3 days. A total of 77 differentially expressed (DE) miRNAs were identified in BF, of which 42 DE miRNAs were upregulated and 35 DE miRNAs were downregulated. A gene ontology analysis showed that genes associated with cellular processes, cells, and binding were enriched. Moreover, pathway analyses suggested that apoptosis, T cell receptor signaling pathways, and chemokine signaling pathways may be activated following vvIBDV infection. In addition, we predicted the target genes of DE miRNAs and constructed an miRNA-mRNA regulatory network. In total, 189 pairs of miRNA-target genes were identified, comprising 67 DE miRNAs and 73 mRNAs. In this network, gga-miR-1684b-3p was identified with the highest fold change, as well as gga-miR-1788-3p and gga-miR-3530-5p showed a high degree of change. The above three miRNAs were considered to play vital roles in vvIBDV-host interactions. This study was the first to perform a comprehensive analysis of DE miRNAs in the bursa of Fabricius in response to vvIBDV infection, and it provided new insights into molecular mechanisms underlying vvIBDV infection and pathogenesis.

Effects of Foliar Application of Nano-molybdenum Fertilizer on Copper Metabolism of Grazing Chinese Merino Sheep (Junken Type) on Natural Grasslands Under Copper and Cadmium Stress

In recent decades, the groundwater contaminated by mineral development and metal smelting has seriously polluted natural grasslands, resulting in heavy metal residues in soils and forages exceeding the standard, especially copper (Cu) and cadmium (Cd). After animals intake contaminated forages, heavy metals may accumulate in animal tissues and threaten human health through the food chain. Previous studies found that molybdenum (Mo) fertilizer from ammonium molybdate or potassium molybdate could alleviate the decrease of antioxidant capacity caused by heavy metal poisoning, but the application of nano-Mo fertilizer in sheep is still lacking. To investigate the effects of nano-Mo fertilizer on Cu metabolism of grazing Chinese Merino sheep (Junken Type) on natural pastures under Cu and Cd stress, fertilizing experiment was carried out in the Bayanbulak Grassland in the northwest of Xinjiang Uygur Autonomous Region, China. A total of 24 hm² fenced grassland contaminated by heavy metals was randomly divided into four groups (3 replications/group and 2 hm²/replication). The experimental groups were applied 0 g Mo, 100 g Mo, 200 g Mo, and 300 g Mo per hectare for the control group, group I, group II, and group III, respectively, through foliar spraying fertilization. A total of 72 Chinese Merino sheep (1 year old, 43.8 ± 2.3 kg) grazing on polluted natural grasslands, with 18 sheep per group, were randomly assigned to the experimental pastures for 30 days. The results showed that the Mo content in soil in group II and group III nwas higher than that in the control group (P < 0.05); the Cd content in soil in group II and group III was lower than that in the control group (P < 0.05), and the Cu content in soil in fertilized pastures was lower than that in the control group (P < 0.05). The Mo content in herbage in fertilized pastures was higher than that in the control group (P < 0.05), and the content of Cu in herbage in fertilized pastures was lower than that in the control group (P < 0.05). The contents of iron (Fe) and Mo in blood and liver of grazing animals from fertilized pastures were higher than that in the control group (P < 0.05). The Cd content in blood of grazing animals in group II and group III was lower than that in the control group (P < 0.05). The Cu content in blood and liver of grazing animals in fertilized pastures was lower than that in the control group (P < 0.05). The content of selenium (Se) in blood of grazing animals in group II and group III was higher than that in the control group (P < 0.05). The levels of blood including hemoglobin (Hb), erythrocyte count (RBC), and packed cell volume (PCV) in group II and group III were higher than that in the control group (P < 0.05). The white blood cell (RBC) count in group II and group III was lower than that in the control group (P < 0.05). The activities of serum superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT), and ceruloplasmin (Cp) in group II and group III were higher than that in the control group (P < 0.05). The content of malondialdehyde (MDA) in group II and group III was lower than that in the control group (P < 0.05). In conclusion, the application of nano-Mo fertilizer on Cu- and Cd-contaminated grasslands changed the contents of mineral elements in soil, forage, and blood of grazing sheep, improved the antioxidant capacity, affected the Cu metabolism of grazing Chinese Merino sheep caused by Cu and Cd pollutions, and alleviated the toxic damage of heavy metal pollutions.

Nano-Molybdenum and Macleaya cordata Extracts Improved Antioxidant Capacity of Grazing Nanjiang Brown Goats on Copper and Cadmium-Contaminated Prairies

To investigate the effects of nano-ammonium octamolybdate (nano-Mo) and Macleaya cordata extracts (MCE) on antioxidant capacity of grazing Nanjiang brown goats on natural prairies under Cu and Cd stress, a 2 × 2 factorial design was adopted in this test, and two factors were nano-Mo (0, 10 mg/kg) and MCE (0, 3000 mg/kg). 24 hm² polluted grassland was used in this 30-day trial and was equally divided into twelve fenced units. A total of 36 Nanjiang brown goats (1 year old) with an average body weight (BW) of 40.9 ± 2.1 kg were used in this test. The dietary treatments were (1) CON group, basic diet; (2) Nano-Mo group, basic diet + 10 mg/kg added Mo (nano-Mo); (3) MCE group, basic diet + 3000 mg/kg added MCE; and (4) combined group, basic diet + 10 mg/kg added nano-Mo and 3000 mg/kg added MCE. Nano-Mo or combination of nano-Mo and MCE diets significantly decreased the Cu content in serum and the liver of grazing goats (P < 0.05) and increased the Fe and Mo contents in serum and the liver (P < 0.05). The supplementation of nano-Mo, MCE, and combined diets extremely increased the levels of blood Hb, RBC, and PCV (P < 0.05), as well as the activities of serum SOD, GSH-Px, CAT, and Cp (P < 0.05), and greatly decreased the blood WBC content (P < 0.05) and the serum MDA content (P < 0.05). In conclusion, the application of nano-Mo and/or MCE diets on contaminated grasslands changed the contents of mineral elements in serum and the liver of grazing goats, reduced oxidative stress, and improved antioxidant capacity. The combination of nano-Mo and MCE can alleviate the toxic damage of combined heavy metal contaminations.

The Effects of Oral Administration of Molybdenum Fertilizers on Immune Function of Nanjiang Brown Goat Grazing on Natural Pastures Contaminated by Mixed Heavy Metal

Mineral development and metal smelting seriously polluted the surrounding groundwater and soil, threatening human health through the food chain. To investigate the effects of different sources of molybdenum (Mo) fertilizers on immune function of Nanjiang brown goats grazing on natural pastures under compound pollutions, fertilizing experiment was carried out in Liangshan Yi Nationality Prefecture of the Western Sichuan Plateau, China. Eighteen square hectometers of polluted meadows were fenced and were randomly divided into three groups (3 replications/group and 2 hm²/replication). A total of 54 healthy Nanjiang brown goats with an average BW of 31.6 ± 1.5 kg (1 year old) were used to this 30-day test (18 goats per group). The goats from CON group, AM group, and PM group were orally supplemented with deionized water, 15 mg Mo/BW·d (ammonium molybdate tetrahydrate), and 15 mg Mo/BW·d (potassium molybdate), respectively. Compared to CON group, the serum Fe content of grazing animals from AM group and PM group was 10.05% and 3.45% higher (P < 0.05), and the serum Cu content of grazing animals from AM group and PM group was 69.05% and 67.86% lower, respectively (P < 0.05). Mo fertilization significantly increased the levels of blood Hb, RBC, and PCV, and the activities of serum SOD, GSH-Px, CAT, and Cp of grazing goats (P < 0.05), and also extremely decreased the MDA content of experimental goats fed Mo compared to the control goats (P < 0.05). Compared to CON group, the activities of serum IgG, IgA, IgM, IL-2, and TNF-α of grazing animals from AM group and PM group were significantly increased (P < 0.05), and the levels of serum IL-6 and IL-1β of grazing goats from AM group and PM group were extremely decreased (P < 0.05). In summary, oral Mo fertilizers can alter the contents of serum mineral elements, reduce oxidative stress, improve immune function, and relieve the toxic damage of goats grazing on contaminated natural grasslands.

Whole Transcriptome Profiling of the Effects of Cadmium on the Liver of the Xiangxi Yellow Heifer

Cadmium (Cd) is a major heavy metal toxicant found in industrial zones. Humans and animals are exposed to it through their diet, which results in various physiological problems. In the current study, the toxic effects of Cd on the liver were investigated by whole-transcriptome sequencing (RNA-seq) of the livers of Xiangxi heifers fed a diet with excess Cd. We randomly divided six healthy heifers into two groups. The first group received a control diet, whereas the second group received Cd-exceeding diets for 100 days. After 100 days, the livers were collected. A total of 551 differentially expressed mRNAs, 24 differentially expressed miRNAs, and 169 differentially expressed lncRNAs were identified (p < 0.05, |log2FC| >1). Differentially expressed genes (DEGs) were analyzed by gene ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses. We found that under Cd exposure, DEGs were enriched in the adenosine 5'-monophosphate-activated protein kinase pathway, which is involved in autophagy regulation, and the peroxisome proliferator-activated receptor pathway, which is involved in lipid metabolism. In addition, the apolipoprotein A4 gene, which has anti-inflammatory and antioxidant effects, the anti-apoptotic gene ATPase H+/K+ transporting the nongastric alpha2 subunit, and the cholesterol metabolism-associated gene endothelial lipase gene were significantly downregulated. C-X-C motif chemokine ligand 3, cholesterol 7α-hydroxylase, and stearoyl-CoA desaturase, which are involved in the development of fatty liver, were significantly upregulated. These genes revealed the main effects of Cd on the liver of Xiangxi yellow heifers. The current study provides insightful information regarding the DEGs involved in autophagy regulation, apoptosis, lipid metabolism, anti-inflammation, and antioxidant enzyme activity. These may serve as useful biomarkers for predicting and treating Cd-related diseases in the future.

Ammonia induces autophagy via circ-IFNLR1/miR-2188-5p/RNF182 axis in tracheas of chickens

Ammonia (NH₃ ), an air pollutant in the living environment, has many toxic effects on various tissues and organs. However, the underlying mechanisms of NH₃ -induced tracheal cell autophagy remains poorly understood. In present study, chickens and LMH cells were used as NH₃ exposure models to investigate toxic effects. The change of tracheal tissues ultrastructure showed that NH₃ exposure induced autolysosomes. The differential expression of 12 circularRNAs (circRNAs) was induced by NH₃ exposure using circRNAs transcriptome analysis in broiler tracheas. We further found that circ-IFNLR1 was down-regulated, and miR-2188-5p was up-regulated in tracheal tissues under NH₃ exposure. Bioinformatics analysis and dual luciferase reporter system showed that circ-IFNLR1 bound directly to miR-2188-5p and regulated each other, and miR-2188-5p regulated RNF182. Overexpression of miR-2188-5p caused autophagy and its inhibition partially reversed autophagy in LMH cells which were caused by ammonia stimulation or knockdown of circ-IFNLR1. The expressions of three autophagy-related genes (LC3, Beclin 1, and BNIP3) were observably up-regulated. Our results indicated that NH₃ exposure caused autophagy through circ-IFNLR1/miR-2188-5p/RNF182. These results provided new insights for the study of ammonia on environmental toxicology on ceRNA and circRNAs in vivo and vitro.

Phylogeny of the HO family in cyprinus carpio and the response of the HO-1 gene to adding Bacillus coagulans in feed under Cd2+ stress

The heavy metal cadmium (Cd²⁺) is an environmental pollutant that poses serious health hazards. Due to the increasing contamination of aquatic systems with Cd²⁺, the increased accumulation of Cd²⁺ in fish has become a food safety and public health concern. Heme oxygenase (HO) is an important antioxidant enzyme that plays a key role in defending the body against oxidative damage, but little research has been done in common carp. In this study, 6 HO genes were identified in the common carp genome database. Comparative genomics analysis showed considerable expansion of the HO genes and verified the four-round whole genome duplication (WGD) event in common carp. Phylogenetic analysis revealed that all HO genes of common carp were clustered into orthologous groups, indicating high conservation during evolution. In addition, the tissue distribution results showed that most HO genes had extensive tissue distribution and showed tissue-specific expression patterns. Exposure to 0.5 mg/L Cd²⁺ significantly reduced the expression of TGF-β and IL-10 in common carp, which may indicate that Cd²⁺ exposure can destroy the physical barrier function of the intestine, inhibit intestinal immune defense and induce intestinal inflammation. To find a suitable concentration of Bacillus coagulans that could activate HO-1 genes and the immunity of the organism, we investigated the changes in HO-1 gene expression levels in the intestinal tract of common carp under Cd²⁺ stress at 30 days and 60 days by adding different concentrations of B. coagulans to the feed. Compared with the Cd²⁺ stress group without supplementation, the expression levels of the HO-1 gene in the gut of three different concentrations of B. coagulans were almost increased. And B. coagulans with L2 concentrations had better activation effect on the HO-1 gene. Similarly, compared to the Cd²⁺ stressed group, adding B. coagulans to the diet can almost cause the early upregulation of IL-10 and TGF-β genes. Therefore, the addition of appropriate concentrations of B. coagulans may be a good way to activate HO-1, IL-10, and TGF-β genes, reduce oxidative damage, and encourage the immune.

Oleanolic acid reshapes the gut microbiota and alters immune-related gene expression of intestinal epithelial cells

BACKGROUND

Oleanolic acid (OA) is a pentacyclic triterpenoid compound that is present at high levels in olive oil and has several promising pharmacological effects, such as liver protection and anti-inflammatory, antioxidant, and anticancer effects. The purpose of the present study was to assess whether OA treatment affects gut health compared to a control condition, including gut microbiota and intestinal epithelial immunity.

RESULTS

Illumina MiSeq sequencing (16S rRNA gene) was used to investigate the effect of OA on the microbial community of the intestinal tract, while Illumina HiSeq (RNA-seq) technology was used to investigate the regulatory effect of OA on gene expression in intestinal epithelial cells, which allowed for a comprehensive analysis of the effects of OA on intestinal health. The results showed that the consumption of OA initially controlled weight gain in mice and altered the composition of the gut microbiota. At the phylum level, OA significantly increased the relative abundances of cecum Firmicutes but decreased the abundance of Actinobacteria, and at the genus level it increased the relative abundance of potentially beneficial bacteria such as Oscillibacter and Ruminiclostridium 9. Oleanolic acid treatment also altered the expression of 12 genes involved in the Kyoto Encyclopedia of Genes and Genomes（KEGG）pathways of complement and coagulation cascades, hematopoietic cell lineage, and leukocyte transendothelial migration in intestinal epithelial cells to improve gut immunity.

CONCLUSION

Intake of OA can contribute beneficial effects by optimizing gut microbiota and altering the immune function of intestinal epithelial cells, potentially to improve intestinal health status. © 2021 Society of Chemical Industry.

Pharmacological and ameliorative effects of Withania somnifera against cadmium chloride-induced oxidative stress and immune suppression in Nile tilapia, Oreochromis niloticus

This study was carried out to evaluate the effects of dietary supplementation of aqueous extract of Withania somnifera (W. somnifera) against cadmium chloride-induced toxicity in the Nile tilapia, Oreochromis niloticus. Five experimental groups were designed: group (I) was free from cadmium chloride and W. somnifera and served as a control, group (II) was exposed to 1.775 mg L^-1 of cadmium chloride only (which is equivalent to 1/4 96-h LC50), while groups (III), (IV), and (V) were exposed to 1.775 mg cadmium chloride L^-1 with co-supplementation of dietary W. somnifera in doses of 1.0, 2.0, and 3.0 mL kg^-1 body weight (bwt), respectively. The experiment lasted for 4 weeks. In the second and fourth weeks of the experiment, the following indicators were evaluated: hematological (hemogram and blood protein profile), biochemical (activities of serum liver enzymes, namely alanine transaminase (ALT) and aspartate transaminase (AST)), immunological (immunoglobulin M (IgM), serum lysozyme), and tissue antioxidant changes (malondialdehyde (MDA) levels and activities of catalase (CAT) and superoxide dismutase (SOD)). Additionally, gene expressions of glutathione-S-transferase (GST) in the liver were assessed. At the end of the experiment, all fish in all groups were experimentally challenged with Aeromonas hydrophila and the relative protection survival (RPS) was demonstrated. The results revealed that groups exposed to cadmium chloride toxicity and co-supplemented with dietary aqueous extract of W. somnifera at high doses showed significant ameliorative effects in hemogram parameters, total protein, globulin, IgM, and lysozyme against cadmium chloride-induced toxicity compared to the control group and the group exposed to a sublethal dose of cadmium chloride without co-suplemntation of W. somnifera. The results showed also that groups supplemented orally with W. somnifera at high doses have higher antioxidant activities of CAT and SOD and reduction of MDA formation. Levels of gene expressions of GST in the liver were higher in W. somnifera extract-supplemented groups more than those in the group exposed to cadmium chloride-induced toxicity without W. somnifera supplementation. In addition, the results revealed improved RPS with the dietary supply of W. somnifera extract in high doses. In conclusion, this study showed that the dietary supplementation of W. somnifera extract to diets of O. niloticus could be suggested as an effective way to overcome cadmium chloride-induced toxicity because it improves blood parameters and antioxidants, and it can be used as an immunostimulant against the invading bacterial pathogens.

CircRNA-IGLL1/miR-15a/RNF43 axis mediates ammonia-induced autophagy in broilers jejunum via Wnt/β-catenin pathway

With the continued increase of global ammonia emission, the damage to human or animal caused by ammonia pollution has attracted wide attention. The noncoding RNAs have been reported to regulate a variety of biological processes under different environmental stimulation via ceRNA (competing endogenous RNA) networks. Autophagy is a hallmark of tissue damage from air pollution. However, the specific role of circular RNAs (circRNAs) in the injury of intestinal tissue caused by autophagy remains unclear. Here, we established 42-days old ammonia-exposed broiler models and observed that autophagy flux in broiler jejunum was activated under ammonia exposure. Meanwhile, a total of eight significantly dysregulated expressed circRNAs were obtained and a circRNAs-miRNAs-genes interaction networks were constructed by bioinformatics analysis. Furthermore, an axis named circRNA-IGLL1/miR-15a/RNF43 was predicted to participate in the excessive autophagy by targeting RNF43. The target relationship was proved by dual-luciferase reporter assay in vitro. Mechanistically, downregulated circRNA-IGLL1 could suppress the expression of RNF43 in ammonia-exposed jejunum and the Wnt/β-catenin pathway was activated. Inhibition of miR-15a reversed autophagy caused by downregulated circRNA-IGLL1. CircRNA-IGLL1 could competitively bind miR-15a to regulate RNF43 expression, thus modulating the occurrence of autophagy. Taken together, our results showed that circRNA-IGLL1/miR-15a/RNF43 axis is involved in ammonia-induced intestinal autophagy in broilers.

Distribution of Pb and Se in mouse brain following subchronic Pb exposure by using synchrotron X-ray fluorescence

Lead (Pb) is a well-known neurotoxicant and environmental hazard. Recent experimental evidence has linked Pb exposure with neurological deterioration leading to neurodegenerative diseases, such as Alzheimer's disease. To understand brain regional distribution of Pb and its interaction with other metal ions, we used synchrotron micro-x-ray fluorescence technique (μ-XRF) to map the metal distribution pattern and to quantify metal concentrations in mouse brains. Lead-exposed mice received oral gavage of Pb acetate once daily for 4 weeks; the control mice received sodium acetate. Brain tissues were cut into slices and subjected for analysis. Synchrotron μ-XRF scans were run on the PETRA III P06 beamline (DESY). Coarse scans of the entire brain were performed to locate the cortex and hippocampus, after which scans with higher resolution were run in these areas. The results showed that: a) the total Pb intensity in Pb-exposed brain slices was significantly higher than in control brain; b) Pb typically deposited in localized particles of <10 um2 in both the Pb-exposed and control brain slices, with more of these particles in Pb-exposed samples; c) selenium (Se) was significantly correlated with Pb in these particles in the cortex and hippocampus/corpus callosum regions in the Pb-exposed samples, and the molar ratio of the Se and Pb in these particles is close to 1:1. These results indicated that Se may play a crucial role in Pb-induced neurotoxicity. Our findings call for further studies to investigate the relationship between Pb exposure and possible Se detoxification responses, and the implication in the etiology of Alzheimer's disease.

Cadmium regulates FKBP5 through miR-9-5p and induces carp lymphocyte apoptosis

Cadmium (Cd) is an environmental pollutant produced by industrial activities, which has no known physiological benefits to organisms. In our previous study, the transcriptomic profiles of carp head kidney exposed to Cd was analyzed by genomics technique, and confirmed that miRNAs are important in the head kidney injury of carp induced by Cd, but the specific biological mechanism was unclear. In order to further explore the effect of Cd on carp head kidney lymphocyte damage, we established a model of Cd exposure in vitro. The results showed that Cd could increase the expression of Bax (Bcl-2 associated X protein), Caspase9 (Cysteinyl aspartate specific proteinase 9) and Caspase3 (Cysteinyl aspartate specific proteinase 3), inhibit the expression of Bcl-2 (B cell lymphoma/leukemia 2), and induce apoptosis of carp head kidney lymphocytes. In our previous study, we screened the differentially expressed miRNA in Cd-treated lymphocytes by high-throughput sequencing, and found that there was a significant difference in the expression of miR-9-5p. The expression trend of miR-9-5p in the vitro model was the same as that of high-throughput sequencing. We screened the differentially expressed gene FKBP5 (FK506-binding protein 51) in lymphocytes treated with Cd. It was confirmed by double luciferase reporter gene analysis that FKBP5 was the target gene of miR-9-5p. We established the overexpression/knockdown model of miR-9-5p in carp head kidney lymphocyte in vitro. The results showed that miR-9-5p could inhibit the expression of FKBP5, increase the phosphorylation level of Akt, inhibit apoptosis and improve the cell survival rate in carp head kidney lymphocytes. Together, Cd could down-regulate the expression of miR-9-5p, target up-regulate the expression of FKBP5, inhibit the phosphorylation of Akt, and promote the apoptosis of carp head kidney lymphocytes through mitochondrial pathway.

Cadmium induced oxidative stress, endoplasmic reticulum (ER) stress and apoptosis with compensative responses towards the up-regulation of ribosome, protein processing in the ER, and protein export pathways in the liver of zebrafish

The present study identified that exposure to 5, 10, and 20 µg/L Cd for 48 days reduced growth, increased Cd accumulation and levels of reactive oxygen species (ROS) and lipid peroxidation, and induced ER stress and cellular apoptosis in the liver in a dose-dependent manner. However, the survival rate was not affected by Cd. The increased production of ROS might result from reduced catalase (CAT) and copper/zinc-superoxide dismutase (Cu/Zn-SOD) activities, which might trigger ER stress pathways and subsequently induce apoptotic responses, ultimately leading to growth inhibition. Transcriptomic analyses indicated that the differentially expressed genes (DEGs) involved in metabolic pathways were significantly enriched and dysregulated by Cd, suggesting that metabolic disturbances may contribute to Cd toxicity. However, there were increases in glutathione peroxidase (GPX) activity, protein levels of metallothioneins (MTs) and heat shock protein 70 (HSP70), and mRNA levels of sod1, cat, gpx, mt2, and hsp70. Furthermore, DEGs related to ribosome, protein processing in the ER, and protein export pathways were significantly enriched and up-regulated by Cd. These increases may be compensatory responses following oxidative stress, ER stress, and apoptosis to resist negative effects. Taken together, we demonstrated that environmentally relevant levels of Cd induced adaptive responses with compensatory mechanisms in fish, which may help to maintain fish survival at the cost of growth.

Heat shock proteins took part in oxidative stress-mediated inflammatory injury via NF-κB pathway in excess manganese-treated chicken livers

Manganese (Mn) is an essential metal in humans and animals. However, excess Mn entered environment due to the wide application of Mn in industry and agriculture, and became an environmental pollutant. Exposure to high doses of Mn is toxic to humans and animals (including chickens). Liver is a target organ of Mn poisoning. Nevertheless, there were few studies on whether Mn poisoning damages chicken livers and poisoning mechanism of Mn in chicken livers. Herein, the aim of this study was to explore if oxidative stress, heat shock proteins (HSPs), and inflammatory response were involved in the mechanism of Mn poisoning-caused damage in chicken livers. A chicken Mn poisoning model was established. One hundred and eighty chickens were randomly divided into one control group (containing 127.88 mg Mn kg^-1) and three Mn-treated groups (containing 600, 900, and 1800 mg Mn kg^-1, respectively). Histomorphological structure was observed via microstructure and ultrastructure. Spectrophotometry was used to detect total antioxidant capacity (T-AOC) and inducible nitric oxide synthase (iNOS) activity, as well as nitric oxide (NO) content. And qRT-PCR was performed to measure mRNA expression of inflammatory genes (nuclear factor kappa B (NF-κB), tumor necrosis factor α (TNF-α), cyclooxygenase-2 (COX-2), prostaglandin E2 (PGE2), and iNOS) and heat shock protein (HSP) genes (HSP27, HSP40, HSP60, HSP70, and HSP90). Multivariate correlation analysis, principal component analysis, and cluster analysis were used to demonstrate the reliability of mechanism of Mn poisoning in our experiment. The results indicated that excess Mn led to inflammatory injury at three contents and three time points. Meanwhile, we found that NO content, iNOS activity, and NF-κB, TNF-α, COX-2, PGE2, and iNOS mRNA expression increased after Mn treatment, meaning that exposure to Mn induced inflammatory response via NF-κB pathway in chicken livers. Moreover, excess Mn decreased T-AOC activity, indicating that Mn exposure caused oxidative stress. Furthermore, mRNA expression of above five HSP genes was up-regulated during Mn exposure. Oxidative stress triggered the increase of HSPs and the increase of HSPs mediated inflammatory response induced by Mn. In addition, there were time- and dose-dependent effects on Mn-caused chicken liver inflammatory injury. Taken together, HSPs participated in oxidative stress-mediated inflammatory damage caused by excess Mn in chicken livers via NF-κB pathway. For the first time, we found that oxidative stress can trigger HSP70 and HSPs can trigger poisoning-caused inflammatory damage, which needs to be further explored. This study provided a new insight into environmental pollutants and a reference for further study on molecular mechanisms of poisoning.

Cadmium exposure activates the PI3K/AKT signaling pathway through miRNA-21, induces an increase in M1 polarization of macrophages, and leads to fibrosis of pig liver tissue

Cadmium (Cd) is a toxic substance that pollutes the environment with multiple organs. Long-term exposure to Cd can cause fibrosis in the lungs and other organs of animal body. This article explored the effects of subacute Cd exposure on pig liver fibrosis, as well as the polarization of microRNA (miRNA) and M1/M2 macrophages during this process. Based on the establishment of the pig subacute CdCl2 exposure model, we used immunofluorescence staining, Masson staining, qRT-PCR and western blotting to conduct further research. The results showed that Cd exposure can increase the expression of miRNA-21, decrease the expression of TGF-β and SMAD7, increase the expression of PI3K/AKT signaling pathway, cause the M1/M2 imbalance and the increase of M1 polarization. Meantime, it causes the secretion of inflammatory cytokines (TNF-α, IL-1β, and IL-6), and causes an imbalance in the expression of TIMP1, MMP2, and MMP9, which are related to the degree of fibrosis. And the expression of α-SMA, COL1 and COL3 were up-regulated. In the pig, these results indicate that liver fibrosis caused by subacute CdCl2 exposure is induced by the M1 polarization of macrophages through the PI3K/AKT signaling pathway activated by miRNA-21 signaling pathway. These research results not only enrich the theoretical basis and reference value of Cd toxicology research, but also provide new references and new research ideas for comparative medicine.

MiR-144-3p targets STC1 to activate PI3K/AKT pathway to induce cell apoptosis and cell cycle arrest in selenium deficiency broilers

Selenium (Se) is an indispensable trace element in vertebrate. Se deficiency can damage the immune system. Studies have shown that Se deficiency can cause immune organ damage by regulating the expression of microRNA. Bursa of Fabricius is a special immune organ in poultry. In order to explore the mechanism of bursa of Fabricius injury caused by Se deficiency and the role of miRNA in this process. Firstly, we established the Se deficient model of broilers in vivo and found that Se deficiency could induce apoptosis and cell cycle arrest of bursa of Fabricius cells through Phosphoinositide 3-kinase (PI3K)/Protein Kinase B (AKT) pathway. Secondly, we inferred miRNA (miR-144-3p) and target gene Stanniocalcin 1 (STC1) that may regulate PI3K/AKT pathway through biological analysis system, and further predicted and determined the targeting relationship between them through dual luciferase, it was found that miR-144-3p was highly expressed in the process of cell apoptosis and cell cycle arrest induced by Se deficiency. Finally, in order to further understand whether miR-144-3p/STC1 axis is involved in the process, miR-144-3p knockdown and overexpression experiments were carried out, it was found that miR-144-3p inhibitor can reduce the occurrence of cell apoptosis and cell cycle arrest. In conclusion, Se deficiency can induce apoptosis and cell cycle arrest of bursa of Fabricius in Broilers by up regulating miR-144-3p targeting STC1 and activating PI3K/AKT pathway, leading to injury of bursa of Fabricius in broilers.

Intermittent mild cold stimulation improves the immunity and cold resistance of spleens in broilers

In order to investigate the effect of intermittent mild cold stimulation (IMCS) on immune function of spleens and adaptability to cold stress in broilers, 400 healthy 1-day-old Ross-308 chickens were divided into 5 groups: CC (control) reared in normal thermal environment from 1 to 49 d; CS3, CS4, CS5, and CS6 (treatments) raised at 3°C below the temperature of CC for 3, 4, 5, or 6 h at 1-d intervals from 15 to 35 d, respectively. Subsequently, CS3-6 was raised at 20°C from 36 to 49 d. At 50 d, all groups were exposed to acute cold stress (ACS) for 12 h. The spleen immunity index at 22, 29, 36, 43, and 49 d, expression levels of toll-like receptors (TLRs), cytokines and immunoglobulins at 22, 43, and 49 d and heat shock proteins (HSPs) before and after ACS at 50 d were examined. The spleen index of broilers aged 22 to 49 d did not differ between CS and CC (P > 0.05), and the spleen index of CS5 was higher than that of CS3 at 49 d (P < 0.05). The mRNA levels of TLR5, TLR15, TLR21, and IL-2 in CS3, TLR3, TLR4, TLR15, TLR21, IL-2, IL-6, and IFN-ϒ in CS4, TLR1, TLR3, TLR4, TLR21, IL-2, IFN-a, IFN-ϒ, IgA, and IgG in CS6, but all TLRs, immunoglobulins and cytokines except IFN-ϒ in CS5 differential expressed stably compared with CC at 43 and 49 d (P < 0.05). Compared with Pre-ACS, the mRNA levels of HSP60, HSP70, and HSP90 were upregulated in CS after ACS (P < 0.05). Except for HSP90 mRNA and HSP70 protein in CS6, and HSP90 protein in CS3, the levels of HSPs after ACS in all treatment groups were higher than those in CC (P < 0.05), and the highest HSPs levels after ACS were found in CS5. We concluded that IMCS could enhance immunity of spleens and adaptability to ACS in broilers, besides CS5 was the optimal program.

The contributions of miR-25-3p, oxidative stress, and heat shock protein in a complex mechanism of autophagy caused by pollutant cadmium in common carp (Cyprinus carpio L.) hepatopancreas

Cadmium (Cd) is a toxic heavy metal that can be discharged into water environment through industrial activities, threatening the health of aquatic organisms and humans. MicroRNA (miRNA) plays an important role in the process of autophagy. The purpose of this experiment was to study the mechanism of Cd-induced autophagy in common carp hepatopancreas. We established a Cd poisoning model of common carp and explored ultrastructure, two oxidation indicators, three antioxidant indicators, miR-25-3p, two heat shock proteins (Hsps), and nine autophagy-related genes. The results confirmed that deleterious effect of Cd caused the injury of hepatopancreas and the appearance of hepatopancreas autophagic cells in common carp. At the same time, Cd exposure increased the contents of hydrogen peroxide (H₂O₂) and malonaldehyde (MDA), and decreased the activities of catalase (CAT), superoxide dismutase (SOD), and total antioxidative capacity (T-AOC), meaning that Cd caused oxidative stress via the imbalance between peroxide level and antioxidant capacity. Moreover, exposure to Cd increased mRNA expression of microtubule associated protein-1 light chain 3 beta (LC3-II), Dynein, Beclin 1, autophagy-related gene 5 (Atg5), and autophagy-related gene 12 (Atg12); and decreased mRNA expression of mechanistic target of rapamycin kinase (mTOR), indicating that excess Cd caused autophagy, and AMPK/mTOR/ULK1 signaling pathway took part in autophagy induced by Cd in common carp hepatopancreas. Furthermore, Cd down-regulated miR-25-3p and up-regulated its three target genes (AMPK, ULK1 as well as PTEN), suggesting that miR-25-3p mediated autophagy induced by Cd. In addition, we found that Hsps were activated via the up-regulation of Hsp70 and Hsp90. Moreover, oxidative stress mediated autophagy via Hsps in Cd-treated common carp hepatopancreas and Cd-induced autophagy was time dependent. In summary, miR-25-3p, oxidative stress, and Hsps participated in autophagy caused by Cd in common carp hepatopancreas. This study provided a new idea for the mechanism of Cd-induced autophagy in hepatopancreas.

The combinations of sulfur and molybdenum fertilizations improved antioxidant capacity of grazing Guizhou semi-fine wool sheep under copper and cadmium stress

Mineral development and metal smelting are the main sources of heavy metal pollution, and copper (Cu) and cadmium (Cd) are the most serious mineral elements in heavy metal pollution. Food chain is the main channel for Cu and Cd to enter human body. Excessive accumulation of Cu and Cd can lead to a variety of diseases and threaten human health. Therefore, it is urgent to repair Cu and Cd-contaminated soil. Previous several studies found that sulfur (S) and molybdenum (Mo) had the effect of alleviating the decrease of antioxidant capacity caused by heavy metal poisoning. To investigate the co-combinations of S and Mo fertilizations on antioxidant capacity of grazing Guizhou semi-fine wool sheep in Cu and Cd-contaminated meadow, and explore the control methods of co-pollutions of Cu and Cd in natural pastures, fertilizing and grazing experiments were carried out in the Wumeng Prairie in the northwest of Guizhou Province, Southwest China. 24 hm² Cu and Cd-polluted meadows were fenced, and were randomly divided into four groups with 3 replications per group and 2 hm² per replication. The tested groups included the control group (no fertilizer) and the three treatment groups, applied 40 kg S + 1 kg Mo, 80 kg S + 2 kg Mo, and 120 kg S + 3 kg Mo per hectare for group I, group II, and group III, respectively. 72 healthy Guizhou semi-fine wool sheep (one year old, 33.9 ± 1.2 kg) were randomly assigned to the tested pastures with 18 sheep per group. The grazing experiment lasted for 60 days. The results showed that the contents of Mn, Zn, Mo, and S in herbage in fertilized pastures were higher than that in the control group (P < 0.05). The content of Cu in herbage in fertilized pastures was lower than that in the control group (P < 0.05). The contents of Mn, Zn, Mo, and S in serum of grazing Guizhou semi-fine wool sheep were higher than that in the control group (P < 0.05). The content of Cu in serum of grazing Guizhou semi-fine wool sheep was lower than that in the control group (P < 0.05). The levels of blood Hb, RBC, and PCV, and the activities of serum SOD, GSH-Px, T-AOC, CAT, and Cp in group Ⅲ were higher than that in the control group, group Ⅰ, and group Ⅱ (P < 0.05). The MDA content of sheep in group Ⅲ was lower than that in the other treatment sheep (P < 0.05). In summary, the combinations of S and Mo fertilizers influenced the mineral contents in herbage and serum of grazing Guizhou semi-fine wool sheep. The combinations of 120 kg S + 3 kg Mo fertilizer reduced the toxicity and improved antioxidant capacity of grazing Guizhou semi-fine wool sheep in Cu and Cd-polluted grasslands.

Cadmium promotes apoptosis and inflammation via the circ08409/miR-133a/TGFB2 axis in bovine mammary epithelial cells and mouse mammary gland

Cadmium is a common environmental heavy metal pollutant that can accumulate over long periods of time and cause disease. Thus, analysis of the molecular mechanisms affected by cadmium in the body could be of great significance for the prevention and treatment of cadmium-related diseases. In this study, flow cytometry, immunofluorescence, transmission electron microscopy, H&E (Hematoxylin Eosin) staining and TUNEL (TdT-mediated dUTP Nick-End Labeling) assays were used to verify that cadmium induced apoptosis and immune responses in bovine mammary epithelial cells (BMECs) and in mouse mammary gland. Isolated BMECs cultured with or without cadmium were collected to screen miRNA (microRNA) using high-throughput sequencing. There were 42 differentially-expressed miRNAs among which 27 were upregulated and 15 downregulated including bta-miR-133a, bta-miR-23b-5p, bta-miR-29e, bta-miR-365-5p, bta-miR-615, bta-miR-7, bta-miR-11975, bta-miR-127, and bta-miR-411a. Among those, miR-133a (which can specifically target TGFB2 (Recombinant Transforming Growth Factor Beta 2) was the most significantly downregulated with a fold-change of 5.27 in BMECs cultured with cadmium. Application of the double luciferase reporter system, western blotting, and qRT-PCR (Quantitative Real-time PCR) revealed that circ08409 can directly bind to miR-133a. Experiments demonstrated that circRNA-08409 could adsorb bta-miR-133a. Both circ08409 and TGFB2 significantly increased apoptosis and altered expression level of a series of inflammatory factors in BMECs. In contrast, miR-133a decreased significantly apoptosis and inflammation in the cells. Compared with cultures receiving only cadmium, the miR-133a+cadmium cultures exhibited significant reductions in the occurrence of late apoptosis. Overall, results indicated that circ08409 could relieve the inhibitory effect of miR-133a on TGFB2 expression by combining with miR-133a and subsequently modulating cell proliferation, apoptosis and inflammation. Overall, the data suggested that the circ08409/miR-133a/TGFB2 axis might play a role in mediating the effect of cadmium on BMECs. As such, data provide novel insights into controlling hazards that cadmium could induce in the mammary gland.

miR-217 through SIRT1 regulates the immunotoxicity of cadmium in Cyprinus carpio

MicroRNAs (miRNAs) play a critical role in regulating the response of animals exposed to heavy metal stress. As a globally dispersed heavy metal in aquatic ecosystems, cadmium (Cd) is highly toxic to many aquatic species. However, little is known about the miRNA response to Cd stress in fish. To investigate the regulatory effect of miRNAs in response to Cd, common carp (Cyprinus carpio) were exposed to Cd²⁺-containing water (0.005 mg/L, 0.05 mg/L, 0.5 mg/L) for 30 days. After exposure, Cd²⁺ contents were significantly higher in the kidneys of C. carpio compared to other tissues, when exposed to 0.5 mg/L Cd²⁺. Hematoxylin and eosin staining images revealed that elevated Cd induced inflammatory damage in the kidneys of C.carpio. Further, miRNA sequencing revealed nine differentially expressed miRNAs (miR-217, miR-205 and seven novel miRNAs) in the kidneys, between 0.5 mg/L Cd²⁺ exposure and control groups. Potential target mRNAs of miRNAs suggest that miR-217 is involved in immunotoxicity. miR-217 agomir was intraperitoneally administered to C. carpio and RT-PCR revealed that the expression of IL-8 and SIRT1 decreased, while TLR-4, TRAF6, NF-kB, TNF-α, IL-1β, and TGF-β increased in the kidneys of C.carpio. Additionally, the expression of SIRT1 decreased, while the expression of other mRNAs increased in kidneys of C. carpio exposed to Cd. According to mRNAs expression in the agomir and Cd treatment, miRNAs inhibit the expressions of target mRNAs. These results demonstrate that miR-217 via SIRT1 plays a regulatory role in the immunotoxicity of Cd to C. carpio.

Hydrogen sulfide exposure induces pyroptosis in the trachea of broilers via the regulatory effect of circRNA-17828/miR-6631-5p/DUSP6 crosstalk on ROS production

Hydrogen sulfide (H₂S) is an air pollutant to cause tracheal injury. Pyroptosis is responsible for tissue injury through reactive oxygen species (ROS) production. Competitive endogenous RNAs (ceRNAs) chelate microRNAs and reduce their inhibitory effect on other transcripts, thus affecting ROS levels and pyroptosis. However, it is not clear how H₂S regulates pyroptosis via the ceRNA axis. Therefore, we established a broilers model of H₂S exposure for 42 days to assess pyroptosis and obtain a ceRNA network by immunohistochemistry and RNA sequencing. We detected pyroptosis induced by H₂S and verified circRNA-IGLL1-17828/miR-6631-5p/DUSP6 axis by a double luciferase reporter assay. We also measured ROS levels and the expression of pyroptotic indicators such as (Caspase1) Casp-1, Interleukin 1β (IL-1β) and Interleukin 1β (IL-18). miR-6631-5p knockdown decreased pyroptotic indicators induced by H₂S. Overexpression of miR-6631-5p or DUSP6 knockdown stimulated ROS generation and upregulated pyroptotic indicators. N-acetyl-_L-cysteine (NAC) decreased pyroptotic indicators and ROS levels both induced by miR-6631-5p. Moreover, circRNA-IGLL1-17828, participated in intermolecular competition as a ceRNA of DUSP6. In conclusion, circRNA-IGLL1-17828/miR-6631-5p/DUSP6 crosstalk regulated H₂S-induced pyroptosis in broilers trachea via ROS generation. This is the first study to reveal regulation mechanism of circRNA-related CeRNAs on pyroptosis induced by H₂S, providing important reference for environmental toxicology.

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.

Th1/Th2 imbalance and heat shock protein mediated inflammatory damage triggered by manganese via activating NF-κB pathway in chicken nervous system in vivo and in vitro

Manganese (Mn) is a ubiquitous heavy metal pollutant in environment, and excess Mn can damage nervous system of humans and animals. However, molecular mechanism of Mn-induced poultry neurotoxicity on inflammatory injury is still not fully clear. Thus, the purpose of the conducted research was to explore molecular mechanism of inflammatory injury caused by Mn in chicken nervous system. Two Mn poisoning models were established in vivo and in vitro. One hundred and eighty chickens were randomly separated into four groups. One control group was raised drinking water and standard diet. Three Mn groups were raised drinking water, and the standard diet supplemented with three different concentrations of MnCl2 ∙ 4H2O. There were 45 birds and 3 replicates in each group. Neurocytes from chicken embryos were cultured in mediums without and with six different concentrations of MnCl2 ∙ 4H2O in vitro. Our experiments showed that excess Mn caused cerebral histomorphological structure alternations and damage, and increased the expressions (P < 0.05) of inflammation-related factor NF-κB, TNF-α, iNOS, COX-2, and PTGEs in vivo and in vitro, meaning that excess Mn caused inflammatory damage and inflammatory response in chicken nervous system. Moreover, there were an upregulated IFN-γ mRNA expression and a downregulated IL-4 mRNA expression (P < 0.05) in bird cerebra and embryonic neurocytes after exposure to Mn, indicating that Mn exposure caused Th1/Th2 imbalance and immunosuppression. Additionally, in our research, the elevation (P < 0.05) of five HSPs (HSP27, HSP40, HSP60, HSP70, and HSP90) was found, suggesting that HSPs participated molecular mechanism of Mn stress. In addition, the inflammatory toxicity of Mn to chicken nervous system was time- and dose-dependent. Taken all together, our findings indicated that Th1/Th2 imbalance and HSPs mediated Mn-caused inflammatory injury via NF-κB pathway in chicken nervous system in vivo and in vitro.