Environmental contaminant ammonia triggers epithelial-to-mesenchymal transition-mediated jejunal fibrosis with the disassembly of epithelial cell-cell contacts in chicken

L-selenomethionine inhibits small intestinal ferroptosis caused by ammonia exposure through regulating ROS-mediated iron metabolism

Ammonia is an important component of PM2.5 and PM10, and is also a major harmful gas in intensive and large-scale pig houses, which poses a potential threat to the health of farmers and animals. Intestinal tract is the largest immune organ in the body and is also an important target organ for ammonia exposure. However, the potential toxicity mechanism of ammonia exposure to the intestine remains unclear. L-selenomethionine is an important source of organic selenium with the advantages of high bioavailability, safety and high efficiency. In order to explore the mechanism of ammonia enterotoxicity and the mitigation effect of L-selenomethionine on ammonia enterotoxicity, multi-dimensional ammonia toxicity models and L-selenomethionine intervention models were established in vivo and in vitro. The results showed that ammonia exposure up-regulated the levels of iron, ROS, MDA, and LPO in the small intestinal tissue and the IPEC-J2 cell, down-regulated the activities of antioxidant enzymes and the content of GSH, inhibited the Nrf2 pathway, significantly altered the expression of ferroptosis (TFR-1, FPN-1, FTH1, SLC7A11, GPX4, ACSL4) and intestine tight junctions (Claudin-1, Occludin, ZO-1) genes. Compared with the ammonia exposure group, L-selenomethionine group could significantly improve the changes of these ferroptosis indicators by affecting ROS and iron levels through Nrf2 pathway. Our results indicated that L-selenomethionine inhibited small intestinal epithelial cells ferroptosis caused by ammonia exposure through regulating ROS-mediated iron metabolism.

Selenium Deficiency Causes Iron Death and Inflammatory Injury Through Oxidative Stress in the Mice Gastric Mucosa

Selenium (Se) is a trace element essential for the maintenance of normal physiological functions in living organisms. Oxidative stress is a state in which there is an imbalance between oxidative and antioxidant effects in the body. A deficiency of Se can make the body more inclined to oxidation, which can induce related diseases. The aim of this experimental study was to investigate the mechanisms by which Se deficiency affects the digestive system through oxidation. The results showed that Se deficiency treatment led to a decrease in the levels of GPX4 and antioxidant enzymes and an increase in the levels of ROS, MDA, and lipid peroxide (LPO) in the gastric mucosa. Oxidative stress was activated. Triple stimulation of ROS, Fe2+, and LPO induced iron death. The TLR4/NF-κB signaling pathway was activated, inducing an inflammatory response. The expression of the BCL family and caspase family genes was increased, leading to apoptotic cell death. Meanwhile, the RIP3/MLKL signaling pathway was activated, leading to cell necrosis. Taken together, Se deficiency can induce iron death through oxidative stress. Meanwhile, the production of large amounts of ROS activated the TLR4/NF-κB signaling pathway, leading to apoptosis and necrosis of the gastric mucosa.

Protein lysine acetylation played an important role in NH3-induced AEC2 damage and pulmonary fibrosis in piglets

Gaseous ammonia (NH3), as a main air pollutant in pig farms and surrounding areas, directly affects animal and human health. The lung, as an important organ for gas exchange in the respiratory system, is damaged after NH3 exposure, but the underlying mechanism needs to be further explored. In this study, seven weeks old piglets were exposed to 50 ppm NH3 for 30 days, and displayed pulmonary fibrosis. Then, the toxicological mechanism of NH3-induced pulmonary fibrosis was explored from the aspects of whole genome wide protein expression and post-translational modification. Totally, 404 differentially expressed proteins (DEPs) and 136 differentially lysine acetylated proteins (DAPs) were identified. The expression or lysine acetylation levels of proteins involved in mitochondrial energy metabolism including fatty acid oxidation (CPT1A, ACADVL, ACADS, HADHA, and HADHB), TCA cycle (IDH2 and MDH2), and oxidative phosphorylation (NDUFB7, NDUFV1, ATP5PB, ATP5F1A, COX5A, and COX5B) were significantly changed after NH3 exposure, which suggested that NH3 disrupted mitochondrial energy metabolism in the lung of piglets. Next, we found that type 2 alveolar epithelial cells (AEC2) damaged after NH3 exposure in vivo and in vitro. Integrin-linked kinase (ILK) was enriched in focal adhesion pathway, and showed significantly up-regulated acetylation levels at K191 (FC = 2.99) and K209 sites (FC = 1.52) after NH3 exposure. We illustrated that ILK-K191 hyper-acetylation inhibited AEC2 proliferation and induced AEC2 apoptosis by down-regulating pAKT-S473 in vitro. In conclusion, for the first time, our study revealed that protein acetylation played an important role in the process of NH3-induced pulmonary fibrosis in piglets. Our findings provided valuable insights into toxicological harm of NH3 to human health.

Selenium Deficiency Promotes the Expression of LncRNA-MORC3, Activating NLRP3-Caspase-1/IL-1β Signaling to Induce Inflammatory Damage and Disrupt Tight Junctions in Piglets

Selenium (Se), as a trace element, is widely found in animals in the form of selenomethionine, which can provide nutrition to the body and has anti-inflammatory effects to prevent inflammatory damage in animals. In the past decade, there have been many studies on piglet diseases caused by selenium deficiency; however, under Se deficiency, the relationship between LncRNA-MORC3, inflammatory injury, and tight junctions in piglets has not yet been studied. We established piglet selenium deficiency models divided into three groups and obtained small intestinal tissues after 35 days of feeding. Small intestinal epithelial IPEC-J2 cells were divided into three groups, and samples were collected after 24 h of culture for qPCR and Western blot experiments. First, we found that Se deficiency led to an increase in LncRNA-MORC3 expression in piglets in vivo and in vitro. We found that the binding site of NLRP3 on LncRNA-MORC3 and the expression trends of both were the same: Se deficiency increased the secretion of NLRP3 and the expression levels of the inflammatory factors Caspase-1, ASC, IL-1β, IL-17, IL-6, IL-10, and TNF-α, which are related to the NLRP3-Caspase-1/IL-1β signaling pathway. At the same time, Se deficiency decreased the expression levels of the tight junction factors ZO-1, Z0-2, Occludin, E-cadherin, and ZEB-1. This result showed that the tight junctions were disrupted. Herein, we demonstrated that Se deficiency promotes the expression of both LncRNA-MORC3 and inflammatory factors in piglets to activate the NLRP3-Caspase-1/IL-1β signaling pathway and disrupt tight junctions. Ultimately, these factors lead to inflammatory damage in piglet small intestinal tissues.

Selenium Deficiency Leads to Reduced Skeletal Muscle Cell Differentiation by Oxidative Stress in Mice

Selenium (Se) is one of the essential trace elements in animal organisms with good antioxidant and immune-enhancing abilities. In this study, we investigated the effect and mechanism of Se deficiency on skeletal muscle cell differentiation. A selenium-deficient skeletal muscle model was established. The skeletal muscle tissue and blood Se content were significantly reduced in the Se deficiency group. HE staining showed that the skeletal muscle tissue had a reduced myofiber area and nuclei and an increased myofascicular membrane with Se deficiency. The TUNEL test showed massive apoptosis of skeletal muscle cells in Se deficiency. With Se deficiency, reactive oxygen species (ROS) and malondialdehyde (MDA) increased, and the activities of glutathione peroxidase (GSH-Px), total antioxidant capacity (T-AOC), superoxide dismutase (SOD), and catalase (CAT) were inhibited. In in vitro experiments, microscopic observations showed that the low-Se group had reduced C2C12 cell fusion and a reduced number of differentiated myotubes. In addition, qPCR results showed that differentiation genes (Myog, Myod, Myh2, Myh3, and Myf5) were significantly reduced in the low Se group. Meanwhile, Western blot analysis showed that the levels of differentiation proteins (Myog, Myod, and Myhc) were significantly reduced in the low-Se group. This finding indicates that Se deficiency reduces the expression of skeletal muscle cell differentiation factors. All the above data suggest that Se deficiency can lead to oxidative stress in skeletal muscle, resulting in a reduction in the differentiation capacity of muscle cells.

Selenium Deficiency Caused Fibrosis as an Oxidative Stress-induced Inflammatory Injury in the Lungs of Mice

Selenium (Se) is a vital trace element in the regulation of inflammation and antioxidant reactions in both animals and humans. Se deficiency is rapidly affecting lung function. The present study investigated the molecular mechanism of Se deficiency aggravates reactive oxygen species (ROS)-induced inflammation, leading to fibrosis in lung. Mice fed with different concentrations of Se to establish the model. In the Se-deficient group, the ROS and malondialdehyde (MDA) was increased, and the activities of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), total antioxidant capacity (T-AOC), and catalase (CAT) reduced. The histopathological observation showed that Se deficiency lead to lung texture damage with varying degrees of degeneration, necrosis, shedding of some alveolar epithelial cells, and inflammatory cell infiltration. Immunohistochemistry showed that the expression of α-smooth muscle actin (α-SMA) increased. The fibrosis index was verified with Sirius red staining. The ELISA and qPCR results showed that the inflammatory cytokines (TNF-α and IL-1β) and ECM (collagen I, collagen IV, fibronectin, and laminin) were increased with ROS increasing, which was induced by Se deficiency. The results displayed that oxidative stress with Se deficiency led to an increase in tissue inhibitors of metalloproteinase (TIMPs), but a decrease in matrix metalloproteinases (MMPs). All the results indicated that Se deficiency induced excessive ROS accumulation to generate inflammation, which disrupted ECM homeostasis and aggravated fibrosis in the lung.

Exposure to polystyrene microplastics triggers lung injury via targeting toll-like receptor 2 and activation of the NF-κB signal in mice

Microplastics are ubiquitous pollutants with a wide range of plastic applications. More recently, microplastics are in the air and can be inhaled into the lungs, causing respiratory diseases. Knowledge of the underlying mechanisms by which microplastics may induce respiratory disease is still limited. This study used intranasal instillation to develop a model of lung injury. The histopathology result showed that the mouse lung had severe inflammatory responses, apoptosis and collagen deposition with chronic exposure to different sizes (Small: 1-5 μm and Large: 10-20 μm) of polystyrene microplastics (PS-MPS), and the damage of smaller sizes was obvious. The expression levels of the Toll-like receptors (TLRs) family, evolutionarily conserved pattern recognition receptors, were detected, and the levels of TLR2 mRNA was significantly increased. In transfection experiments, PS-MPS increased the inflammatory response in HEK293 cells with TLR2 expression. Furthermore, exposure to small polystyrene microplastics promoted oxidative stress and apoptosis, and accelerated the process of fibrosis. Interestingly, inhibition of the NF-κB signal relieves inflammation and oxidative stress, reduces apoptosis, and thus controls the fibrosis process. These results suggested that PS-MPS targeted binding to TLR2 and further exacerbated fibrosis by facilitating inflammation, oxidative stress, and apoptosis with the activation of NF-κB signal.

Zinc Deficiency Induces Inflammation and Apoptosis via Oxidative Stress in the Kidneys of Mice

Zinc (Zn) is an essential element that regulates not only cellular immunity but also antioxidant and anti-inflammatory agents. The present study investigated the effect of Zn deficiency on renal cell apoptosis and its mechanism. A Zn-deficient kidney model in mice was created by a Zn-deficient diet. Mice were fed diets with different Zn levels for 41 days as follows: normal-Zn group (NG, 34 mg Zn/kg), low-Zn group (LG, 2 mg Zn/kg), and high-Zn group (HG, 100 mg Zn/kg). H&E staining showed that inflammatory cells and many erythrocytes exuded in the renal tissue space of the low-Zn group, and TUNEL staining indicated massive death of kidney cells in the low-Zn group. In the low-Zn group, the levels of oxygen free radicals (ROS) were significantly increased, the antioxidants were significantly decreased, and the total antioxidant capacity was decreased. Moreover, RT-qPCR and ELISA results showed that inflammatory factors (TNF-α, IL-1β, and IL-6) were significantly increased in the low-Zn group. In addition, the levels of p-IκBα, p-NF-κB p65, p-ERK, p-JNK, and p-p38 were significantly increased in the low-Zn group, indicating that zinc deficiency activates NF-κB and MAPK signalling as well as increases its expression. RT-qPCR analysis of apoptosis-related genes, including Bcl-2 Bax, Caspa8, Caspa6, and Caspa3, demonstrated that the expression levels of proapoptotic genes in mouse kidneys were significantly increased. Importantly, the in vitro results were consistent with the in vivo results. Together, these data suggested that zinc deficiency induces renal oxidative stress to activate NF-κB and MAPK signalling, thereby inducing renal cell apoptosis.

Intestinal barrier dysfunction induced by ammonia exposure in pigs in vivo and in vitro: The protective role of L-selenomethionine

Ammonia has been reported to have a variety of toxicity to aquatic animals, farm animals and humans. However, its potential toxicity on the intestines remains unknown. L-selenomethionine is one of the important organic selenium sources. However, the mitigating effect of L-selenomethionine on ammonia exposure toxicity is still lacking. Therefore, in this study, the mechanism of toxic action of ammonia on intestinal tract and the detoxification effect of L-selenomethionine were examined. We evaluated the intestinal toxicity of ammonia and the alleviating effect of L-selenomethionine in an in vivo model, and then verified it in vitro model by a variety of cutting-edge experimental techniques. Our results showed that ammonia exposure causes oxidative stress, necroptosis, Th1/Th2 imbalance and inflammation in the intestinal tissue and the intestinal cells, and L-selenomethionine had a significant mitigation effect on the changes of these indexes induced by ammonia. In conclusion, ammonia exposure caused oxidative stress and Th1/Th2 imbalance in the porcine small intestine and IPEC-J2 cells, and that excessive ROS accumulation-mediated necroptosis targeted inflammatory responses, resulting in the destruction of tight connections of intestinal cells, thereby causing intestinal barrier dysfunction. L-selenomethionine could effectively reduce the intestinal injury caused by ammonia exposure and antagonize the toxic effect of ammonia.

Recent evidence for toxic effects of NH3 exposure on lung injury: Protective effects of L-selenomethionine

Ammonia (NH₃) is a common air pollutant, which poses a serious threat to farm animals. L-selenomethionine is organic selenium (Se), which can inhibit intracellular ROS generation, block ROS-dependent autophagy, promote mitochondrial energy metabolism, and enhance the body's immunity. Lung, as an important organ of the respiratory system, is highly susceptible to the toxic effects of NH₃. However, there were few studies on the mechanism of toxic effects of NH₃ on lung tissues. The aim of this study was to investigate the effect of NH₃ on the lungs in pigs and the alleviating effect of L-selenomethionine. Twenty-four Large White*Duroc*Min pigs were randomly assigned to 4 groups: control group, NH₃ group, Se group, and NH₃ +Se group. The results showed that exposure to NH₃ caused damage and inflammation in lung tissues and significantly increased blood NH₃ concentration. NH₃ induced changes of oxidative stress indexes (GSH, GSH-Px, SOD, MDA, Keap1, Nrf2, and HO-1) and expressions of energy metabolism related genes (HK1, HK2, PFK, PK, LDHA, and HIF-1α). Ultrastructure showed that mitochondrial damage and autophagosome increased significantly, and the expression levels of autophagy related genes (Beclin1, ATG5, ATG7, ATG10, and p62) changed. However, the addition of L-selenomethionine alleviated the above changes, but there was still a significant difference compared with the control group (P < 0.05). This finding can provide a new evidence for mitigation of NH₃ toxicity.

Zinc Deficiency Aggravates Oxidative Stress Leading to Inflammation and Fibrosis in Lung of Mice

Zinc (Zn) is an essential trace element for the body. Studies have confirmed that Zn deficiency can cause oxidative stress. The purpose of the present study was designed to investigate the effect of Zn on fibrosis in lung of mice and its mechanism. Mice were fed with different Zn levels dietary, then we found that the Zn-deficient diet induced a decrease of Zn level in lung tissue. The results also revealed the alveolar structure hyperemia and an inflammatory exudated in the alveolar cavity. Moreover, immunohistochemical results showed that the expression of α-smooth muscle actin (α-SMA) increased. And the Sirius red staining indicated an increase in collagen with Zn deficiency. Furthermore, oxygen radicals (ROS) levels were significantly increased, and the antioxidants were significantly decreased. Meanwhile, inflammatory factors (TNF-α and IL-1β) were remarkably increased, and the ELISA results showed that collagen I, III, and IV and fibronectin (FN) were increased. In addition, the expressions of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinase (TIMPs) were detected by qPCR. The results showed that the expression of TIMPs was increased but the expression of MMPs was decreased. The results of the experiment in vitro were consistent with that in vivo. All the results indicated that Zn deficiency aggravated the oxidative stress response of lung tissue to induce inflammation, leading to fibrosis in lung.

Selenium Deficiency Leads to Inflammation, Autophagy, Endoplasmic Reticulum Stress, Apoptosis and Contraction Abnormalities via Affecting Intestinal Flora in Intestinal Smooth Muscle of Mice

Selenium (Se) is a micronutrient that plays a predominant role in various physiological processes in humans and animals. Long-term lack of Se will lead to many metabolic diseases. Studies have found that chronic Se deficiency can cause chronic diarrhea. The gut flora is closely related to the health of the body. Changes in environmental factors can cause changes in the intestinal flora. Our study found that Se deficiency can disrupt intestinal flora. Through 16s high-throughput sequencing analysis of small intestinal contents of mice, we found that compared with CSe group, the abundance of Lactobacillus, Bifidobacterium, and Ileibacterium in the low selenium group was significantly increased, while Romboutsia abundance was significantly decreased. Histological analysis showed that compared with CSe group, the small intestine tissues of the LSe group had obvious pathological changes. We examined mRNA expression levels in the small intestine associated with inflammation, autophagy, endoplasmic reticulum stress, apoptosis, tight junctions, and smooth muscle contraction. The mRNA levels of NF-κB, IκB, p38, IL-1β, TNF-α, Beclin, ATG7, ATG5, LC3α, BaK, Pum, Caspase-3, RIP1, RIPK3, PERK, IRE1, elF2α, GRP78, CHOP2, ZO-1, ZO-2, Occludin, E-cadherin, CaM, MLC, MLCK, Rho, and RhoA in the LSe group were significantly increased. The mRNA levels of IL-10, p62 BcL-2 and BcL-w were significantly decreased in the LSe group compared with the CSe group. These results suggest that changes in the abundance of Lactobacillus, bifidobacterium, ileum, and Romboutsia may be associated with cellular inflammation, autophagy, endoplasmic reticulum stress, apoptosis, tight junction, and abnormal smooth muscle contraction. Intestinal flora may play an important role in chronic diarrhea caused by selenium deficiency.

Selenium Deficiency Promotes Oxidative Stress-Induced Mastitis via Activating the NF-κB and MAPK Pathways in Dairy Cow

Selenium (Se) is an antioxidant and immunomodulator that can participate in the control of specific endocrine pathways. Disturbance of redox homeostasis is closely related to the pathogenesis of many diseases. Se is also an important nutrient element for dairy cows. First, oxidative stress (OS) induced by Se deficiency was investigated along with a possible mechanism of its induction of mammary gland inflammation. This investigation used in vivo and in vitro experiments for verification. Once the OS response was triggered, the activity of antioxidant enzymes was reduced by regulation of the concentration of Se, which led to the accumulation of ROS. TNF-α, IL-1β, and IL-6 secretion was promoted to activate the NF-κB/MAPK signaling pathway. This process further promoted the accumulation of cytokines that aggravated the inflammatory response. Herein, it was verified that Se deficiency induces OS, which leads to ROS accumulation and the secretion of inflammatory factors to activate the NF-κB/MAPK signaling pathway and promote the occurrence of mastitis.

A new discovery of polystyrene microplastics toxicity: The injury difference on bladder epithelium of mice is correlated with the size of exposed particles

Microplastics (MPs), as widespread hazardous substances in the environment, can cause potential adverse effects on biological health. However, reports on the toxic effects of different diameters MPs on urinary system are limited. Here, we investigated the types and mechanisms of damage to mice bladder epithelial cells treated with diameter (1-10 μm and 50-100 μm) polystyrene microplastics (PS-MPs). The results showed that exposure to PS-MPs of both diameters resulted in necroptosis and inflammation to bladder epithelium. However, 1-10 μm PS-MPs posed more severe necroptosis and 50-100 μm PS-MPs led to a higher degree of inflammatory injury at the same exposure concentration. Mechanistically, PS-MPs were found to induce necroptosis as well as p-NFκB-mediated inflammation by triggering oxidative stress and excessive release of reactive oxygen species (ROS). Furthermore, N-Acetyl-l-cysteine (NAC) attenuated the toxic effects of PS-MPs on bladder epithelial cells. In conclusion, our study demonstrated for the first time that PS-MPs caused necroptosis and inflammation in mice bladders tissues, and the difference of injury correlates with the size of PS-MPs particles.

Melatonin ameliorates nickel induced autophagy in mouse brain: diminution of oxidative stress

Nickel（Ni) is a neurotoxic environmental pollutant. Oxidative stress is thought to be the main mechanism behind the development of Ni neurotoxicity. Melatonin (Mt) has significant efficacy as an antioxidant. In this paper, we investigated the damage that Ni causes to the autophagy of the nervous system. Furthermore, Mt has can intervene upon the damage caused by Ni, which can protect the nervous system. Herein, we randomly divided 80 8-week-old male wild-type C57BL/6N mice into four groups, including the C group, Ni group, Mt group, and Mt+Ni group. Ni was gavaged at a concentration of 10mg/kg, while was Mt was administered at a concentration of 2mg/kg for 21 days at 0.1ml/10g body weight of the mice. Histopathological and ultrastructural observations demonstrated altered states, such as neuronal atrophy, as well as typical autophagic features in the Ni group. Mt was able to intervene effectively in Ni-induced neurotoxicity. The antioxidant capacity assay also demonstrated that Ni can lead to a large amount of reactive oxygen species (ROS) production within the mouse brain. Furthermore, the same Mt was effective at reducing ROS production. In order to further illustrate this point, we added the broad-spectrum phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002 to NS20Y cells. The presence of inhibitors effectively demonstrates that, within the PI3K/AKT/mTOR pathway, autophagy occurs. In conclusion, these data suggest that Ni causes oxidative stress damage and induces autophagy within the mouse brain by inhibiting the PI3K/AKT/mTOR pathway, and that Mt can effectively alleviate the oxidative stress caused by Ni, and reducing Ni induces autophagy in the mouse brain through the PI3K/AKT/mTOR pathway.

Melatonin relieves liver fibrosis induced by Txnrd3 knockdown and nickel exposure via IRE1/NF-kB/NLRP3 and PERK/TGF-β1 axis activation

AIMS

Nickel(Ni) accumulates in the environment due to human activities such as electroplating, alloy production, stainless steel, Ni‑cadmium batteries and industrial production. Ni enriched in humans and animals through food chains, poses a serious health threat. Txnrd3, as a member of the thioredoxin reductase family, has long been thought to be testicular specific and involved in sperm maturation. However, its role in liver diseases still unknown. Melatonin exerts its antioxidant effects directly through its ability to clear free radicals and protects the liver from oxidative damage. Hepatic fibrosis with an ever-increasing incidence year by year, is correlating with outcome and risk of hepatocellular carcinoma.

MATERIALS AND METHODS

In this study, 60 8-week-old male C57BL/6 wild-type mice and 60 Txnrd3-/- mice were randomly divided into three groups, respectively. Control group was gavaged with distilled water, 10 mg/kg NiCl₂ in Ni group, Ni + Mel group treated with 2 mg/kg melatonin in the morning, 10 mg/kg NiCl₂ in the afternoon, serum and tissue was extracted after 21 days.

KEY FINDINGS

Results showed that liver function was significantly worse after Ni exposure, morphological and masson staining showed more significant liver fibrosis in Txnrd3-/- mice, damage of organelles in hepatocytes was observed. qPCR and WB results showed activation of the IRE1/Nuclear factor-kappa B/NLRP3 axis during Ni exposure lead to hepatocyte pyroptosis, while upregulation of PERK/TGF-β promoted liver fibrosis process and Txnrd3 knockout exacerbated liver damage during Ni exposure.

SIGNIFICANCE

The above results will lay the theoretical foundation for the monitoring and clinical treatment of Ni exposure.

Protective Effect of Selenium-Enriched Green Tea on Carbon Tetrachloride-Induced Liver Fibrosis

The major pathogenic feature of liver fibrosis is that oxidative stress motivation of hepatic stellate cells (HSCs) alters the balance between the synthesis and degradation of extracellular matrix (ECM) and HSCs into proliferative myofibroblasts. Green tea and selenium (Se) can protect the liver from damage; however, the precise mechanism of green tea and the action of Se in green tea on hepatic fibrosis remain unclear. Several studies have demonstrated the profibrogenic role of 5-hydroxytryptamine (5-HT) and 5-hydroxytryptamine receptor (5-HTR) 2A/2B in the liver. The current study aimed to investigate the protective effects and possible mechanisms of selenium-enriched green tea on carbon tetrachloride (CCl₄)-induced liver fibrosis in male C57BL/6 J mice. After a 4-week intervention with tea solution, histological analysis of the liver showed that green tea interventions alleviated hepatic fibrosis, which was supported by the changes in collagen type I, collagen type III, and α-smooth muscle actin in the liver. Tea interventions significantly inhibited the CCl₄-provoked increase of duodenal 5-HT and tryptophan hydroxylase and hepatic 5-HT and 5-HTR2A/2B levels. All of them were lower in the selenium-enriched green tea group than in regular green tea group. Se-enriched green tea had a more pronounced improvement in liver ECM deposition and scar formation and peripheral 5-HT signals than regular green tea. Thus, green tea, especially those enriched with selenium, can improve liver fibrosis through intestinal 5-HT-hepatic 5-HTR signaling.

Long-term exposure to low concentrations of MC-LR induces blood-testis barrier damage through the RhoA/ROCK pathway

Microcystin-leucine arginine (MC-LR), an emerging water pollutant, produced by cyanobacteria, has an acute testicular toxicity. However, little is known about the chronic toxic effects of MC-LR exposure on the testis at environmental concentrations and the underlying molecular mechanisms. In this study, C57BL/6 J mice were exposed to different low concentrations of MC-LR for 6, 9 and 12 months. The results showed that MC-LR could cause testis structure loss, cell abscission and blood-testis barrier (BTB) damage. Long-term exposure of MC-LR also activated RhoA/ROCK pathway, which was accompanied by the rearrangement of α-Tubulin. Furthermore, MC-LR reduced the levels of the adherens junction proteins (N-cadherin and β-catenin) and the tight junction proteins (ZO-1 and Occludin) in a dose- and time-dependent way, causing BTB damage. MC-LR also reduced the expressions of Occludin, ZO-1, β-catenin, and N-cadherin in TM4 cells, accompanied by a disruption of cytoskeletal proteins. More importantly, the RhoA inhibitor Rhosin ameliorated these MC-LR-induced changes. Together, these new findings suggest that long-term exposure to MC-LR induces BTB damage through RhoA/ROCK activation: involvement of tight junction and adherens junction changes and cytoskeleton disruption. This study highlights a new mechanism for MC-LR-induced BTB disruption and provides new insights into the cause and treatment of BTB disruption.

Selenium Alleviates Inflammation in Staphylococcus aureus-Induced Mastitis via MerTK-Dependent Activation of the PI3K/Akt/mTOR Pathway in Mice

Mastitis caused by Staphylococcus aureus infection not only causes serious economic losses, but also affects human health. Se plays an important role in body immunity. However, the mechanisms by which Se regulates mastitis induced by S. aureus are still principally unknown. The purpose of this study is to investigate whether Se can inhibit mastitis induced by S. aureus through regulation of MerTK. Sixty BALB/c female mice were fed low, normal, or high Se concentrations for 7 weeks and then randomly divided into six groups (Se-Low Control group (LSN), Se-Normal Control group (NSN), Se-High Control group (HSN), Se-Low S. aureus group (LSS), Se-Normal S. aureus group (NSS), Se-High S. aureus group (HSS)). The regulation of Se on MerTK was detected via histopathological staining, western blot analysis, enzyme-linked immunosorbent assay, and qRT-PCR. With increased selenium concentrations, the levels of IL-1β, IL-6, and TNF-α decreased, while the phosphorylation levels of MerTK, PI3K, AKT, and mTOR increased. Therefore, this study showed that Se could alleviate S. aureus mastitis by activating MerTK and PI3K/AKT/mTOR pathway.

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.

TMT induces apoptosis and necroptosis in mouse kidneys through oxidative stress-induced activation of the NLRP3 inflammasome

Trimethyltin chloride (TMT) is an organotin heat stabilizer that is widely used in the production of plastics, and has strong toxicity. Here, the effect of trimethyltin chloride on mouse kidneys and its related mechanism were studied by taking TMT mouse with drinking water as a model. Histological examination and TUNEL results showed that the trimethyltin chloride group had typical apoptosis and necroptosis characteristics. Therefore, the level of oxidative stress was detected,and the expression of related genes was verified by real-time quantitative polymerase chain reaction (qRT-PCR) and Western blot methods. The results showed that oxidative stress was activated (MDA,SOD,CAT,T-AOC), released ROS, activated NF-κB pathway,activated inflammasome (NLRP3,Caspase-1,ASC), and inflammasome-secreted inflammatory factors (IL-1β). The expression of apoptosis (BCL-2, BAX, Caspase-3, Caspase-9) and necroptosis (RIPK1, RIPK33, MLKL, Caspase-8) increased.In addition, HEK293T human embryonic kidney cells were treated with trimethyltin chloride, and the results were similar to the tissue. In conclusion, TMT can induce oxidative stress, activate NF-κB pathway, and induce apoptosis and necroptosis through inflammasomes.

Exosomal lnc-AFTR as a novel translation regulator of FAS ameliorates Staphylococcus aureus-induced mastitis

Although the specific expression of long noncoding RNA (lncRNA) in mastitis tissue has been reported, few studies have involved the differential expression of lncRNA in mastitis exosomes (Exo) and its mechanism and function. We screened an lncRNA associated with FAS translational regulation (lnc-AFTR) through exosomal RNA sequencing, and clarified its function and molecular mechanism. Lnc-AFTR is markedly downregulated in Staphylococcus aureus-Exo and S. aureus-induced MAC-T cell as well as mastitis tissue. Overexpression of lnc-AFTR exosomes (oe-AFTR-Exo) significantly improves cell damage induced by S. aureus, including inhibiting apoptosis, promoting proliferation, and increasing the production of pro-inflammatory cytokines (tumor necrosis factor-α [TNF-α] and interleukin-1β [IL-1β]). Oe-AFTR-Exo also suppressed the activation of Caspase-8, Caspase-3, and JNK. Dual-luciferase report analysis confirmed that lnc-AFTR interacts with FAS mRNA directly to hinder translation process, but does not degrade FAS mRNA. Overexpression of lnc-AFTR in MAC-T cells obviously reduced S. aureus-induced apoptosis and inflammation. Knockdown of lnc-AFTR significantly increased FAS and promoted the activation of Caspase-8, Caspase-3, and JNK caused by S. aureus. In summary, these results revealed the mechanism by which lnc-AFTR directly bound FAS mRNA to prevent translation, and confirmed that the exosomal lnc-AFTR exerted anti-inflammatory and anti-apoptotic effects by inhibiting the activation of TNF signaling pathway and mitogen-activated protein kinases (MAPK) signaling pathway.

Glycolysis and Reactive Oxygen Species Production Participate in T-2 Toxin-Stimulated Chicken Heterophil Extracellular Traps

T-2 toxin (T-2) is a kind of trichothecene toxin produced from Fusarium fungi, which is an environmental pollutant that endangers poultry and human health. Heterophil extracellular traps (HETs) are not only a form of chicken immune defense against pathogen infection but also involved in pathophysiological mechanisms of several diseases. However, the immunotoxicity of T-2 on HET formation in vitro has not yet been reported. In this study, heterophils were exposed to T-2 at doses of 20, 40, and 80 ng/mL for 90 min. Observation of the structure of HETs by immunofluorescence staining and the mechanism of HET formation was analyzed by inhibitors and PicoGreen. These results showed that T-2-triggered HET formation consisted of DNA, elastase, and citH3. Furthermore, T-2 increased reactive oxygen species (ROS) generation, and the formation of T-2-triggered HETs was also decreased by the inhibitors of glycolysis, nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, p38 and extracellular signal-regulated kinase (ERK)_1/2 signaling pathways, suggesting that T-2-induced HETs are associated with glycolysis, ROS production, ERK_1/2 and p38 signaling pathways, and NADPH oxidase. Taken together, this study elucidates the mechanism of T-2-triggered HET formation, and it may provide new insight into understanding the immunotoxicity of T-2 to early innate immunity in chickens.

Pharmacophore based in silico study with laboratory verification-environmental explanation of prostate cancer recurrence

The prediction of harmful effects can guide research on the health hazards of environmental pollutants. The development of a computer-aided drug design in pharmacological technology and omics database remarkably facilitates the prediction of the possible harmful effects of hazardous substances. In this study, the pharmacophore target database based on molecular structure served as a bridge between pollutants and genes and combined with the omics database and molecular pathway enrichment technology to predict the potential prostatic cancer-promoting effect of dibutyl phthalate. Cell experiments and gene expression were carried out to verify the previous prediction, and the characteristics of harmful effects were further explored. Low concentrations of dibutyl phthalate may have androgen-independent prostate cancer-promoting effects, which may put patients receiving androgen deprivation therapy in danger. This study suggests the potential negative effects of phthalates on prostate cancer and a method for predicting harmful effects on the basis of pharmacology technology.

Metabolic changes and stress damage induced by ammonia exposure in juvenile Eriocheir sinensis

The application of nitrogen fertilizers in the rice-crab co-culture system may expose juvenile Eriocheir sinensis to high ammonia concentrations within a short period of time, potentially causing death. Currently, the molecular mechanism underlying ammonia toxicity in juvenile Eriocheir sinensis remains poorly understood. This study compared the effects of 24 h exposure to different total ammonia-N concentrations (0, 10.47, and 41.87 mg/L) on antioxidant enzyme activities and tandem mass tag (TMT)-based proteomics in the hepatopancreas of juvenile Eriocheir sinensis. During the experiment, water temperature and pH were maintained at 20.4 ± 1.4 °C and 7.69 ± 0.46, respectively. Proteomic data demonstrated that Eriocheir sinensis used different metabolic regulatory mechanisms to adapt to varying ammonia conditions. The tricarboxylic acid (TCA) cycle, glycogen degradation, and oxidative phosphorylation showed marginally upregulated trends under low ammonia exposure. High ammonia stress caused downregulation of the TCA cycle and provided energy by enhancing oxidative phosphorylation, fatty acid beta oxidation, gluconeogenesis, and glycogen degradation. The detoxification of ammonia into urea and glutamine was suppressed under high ammonia stress. Finally, ammonia exposure induced oxidative stress and caused protein damage. Antioxidant enzyme activity analysis further revealed that exposure to high concentrations of ammonia may induce more severe oxidative stress. This study provides a global perspective on the mechanisms underlying ammonia exposure-induced metabolic changes and stress damage in juvenile Eriocheir sinensis.

Alkaline phosphatase attenuates LPS-induced liver injury by regulating the miR-146a-related inflammatory pathway

Lipopolysaccharide (LPS) can remain in dairy products after the sterilization of milk powder and may pose a threat to the health of infants and young children. There is a large amount of alkaline phosphatase (ALP) in raw milk, which can remove the phosphate bond of LPS, thus, detoxifying it. ALP is regarded as an indicator of the success of milk sterilization due to its strong heat resistance. ALP can alleviate the toxicity of LPS in enteritis and nephritis models, but the mechanism by which oral-intake of ALP protects liver tissue from LPS stimulation is unclear. In this study, an in vivo acute mouse liver injury model was induced by C. sakazakii LPS (200 μg/kg) and used to verify the protective mechanism of ALP (200 U/kg) on mice livers. The related pathways were also verified by in vitro cell culture. Enzyme linked immunosorbent assays (ELISAs), quantitative reverse transcription PCR (RT-qPCR) and western blotting were used to detect the levels of inflammatory factors at the protein level and RNA level, and to confirm the inflammation of liver tissue caused by LPS. ALP was found to alleviate acute liver injury in vitro by activating miR-146a. We found that ALP could up-regulate the level of miR146a and subsequently alleviates the expression of TLR4, TNF-α, matured IL-1β, and NF-κB in mouse liver tissue and hepatocytes; thus, reducing liver inflammation. Herein, we demonstrated for the first time that oral-intake of ALP protected liver tissue by up-regulating the expression of miR-146a and alleviating inflammatory reactions; thus, providing a research basis for the proper processing of milk. This study also suggests that producers should improve the awareness of the protective effects of bioactive proteins in raw milk.

Ammonia impairs tight junction barriers by inducing mitochondrial dysfunction in Caco-2 cells

Ammonia is one of the major metabolites produced by intestinal microorganisms; however, its role in intestinal homeostasis is poorly understood. The present study investigated the regulation of intestinal tight junction (TJ) proteins by ammonia and the underlying mechanisms in human intestinal Caco-2 cells. Ammonia (15, 30, and 60 mM) increased the permeability of the cells in a dose-dependent manner, as indicated by reduced transepithelial electrical resistance and increased dextran flux. Immunoblot and immunofluorescence analyses revealed that the ammonia-induced increase in TJ permeability reduced the membrane localization of TJ proteins such as zonula occludens (ZO)1, ZO2, occludin, claudin-1, and claudin-3. DNA microarray analysis identified a biological pathway "response to reactive oxygen species" enriched by ammonia treatment, indicating the induction of oxidative stress in the cells. Ammonia treatment also increased the malondialdehyde content and decreased the ratio of reduced to oxidized glutathione. Meanwhile, ammonia treatment-induced mitochondrial dysfunction, as indicated by the downregulation of genes associated with the electron transport chain, reduction of the cellular ATP, NADH, and tricarboxylic acid cycle intermediate content, and suppression of the mitochondrial membrane potential. In contrast, N-acetyl cysteine reversed the ammonia-induced impairment of TJ permeability and structure without affecting the mitochondrial parameters. Collectively, ammonia impaired the TJ barrier by increasing oxidative stress in Caco-2 cells. A mitochondrial dysfunction is possibly an event preceding ammonia-induced oxidative stress. The findings of this study could potentially improve our understanding of the interplay between intestinal microorganisms and their hosts.

Molsidomine alleviates acetic acid-induced colitis in rats by reducing oxidative stress, inflammation and apoptosis

Ulcerative colitis (UC) is a subcategory of intestinal inflammatory bowel disease characterized by up-regulation of proinflammatory cytokines and oxidative stress. The current study was designed to assess the probable protective effect of the nitric oxide (NO) donor, molsidomine, in experimental colitis model in rats. Rats were haphazardly classified into four groups: control, acetic acid, acetic acid + molsidomine (1 mg/kg) and acetic acid + molsidomine (2 mg/kg). Molsidomine (1 and 2 mg/kg/day) was administered by intra-peritoneal injection for 7 days prior to induction of UC. On the 8th day, colitis was induced by intra-rectal instillation of 2 ml of (4% v/v) acetic acid in normal saline using a pediatric plastic catheter. The rats were sacrificed 1 day following colitis induction, blood samples were obtained; colons and livers were isolated then underwent macroscopic, biochemical, histopathological and immunohistochemical examination. Pretreatment with molsidomine significantly reduced disease activity index, colon mass index, colonic macroscopic and histological damage. Besides, molsidomine significantly reduced the serum levels of alanine transaminase (ALT) (58.7 ± 8.9 & 59.7 ± 8 vs 288.75 ± 31.4 in AA group) and aspartate transaminase (AST) (196.2 ± 37.4 & 204 ± 30 vs 392.7 ± 35.6 in AA group). Moreover, molsidomine effectively decreased malondialdehyde (MDA) and total nitrate/nitrite (NOx) contents, and up regulated the enzymatic activity of superoxide dismutase (SOD) and glutathione level (GSH) in colonic and hepatic tissues. With regard to anti-inflammatory mechanisms, molsidomine suppressed tumor necrosis factor-alpha (TNF-α) (792.5 ± 16.7 & 448 ± 12.1 vs 1352.5 ± 45.8 in AA group) in colonic tissues and (701 ± 19 & 442.5 ± 22.5 vs 1501 ± 26 in AA group) in hepatic tissues as well as nuclear transcription factor kappa B (NF-kB/p65) levels (416.2 ± 4.1 & 185.5 ± 14.2 vs 659.2 ± 11.5 in AA group) in colonic tissues and (358 ± 6.2 & 163.5 ± 9.6 vs 732.5 ± 5.5 in AA group) in hepatic tissues. In addition, molsidomine significantly decreased inducible nitric oxide synthase (iNOS) levels (8.1 ± 0.1 & 4.9 ± 0.1 vs 16 ± 0.1 in AA group) in colonic tissues and (8.6 ± 0.3 & 6.1 ± 0.1 vs 17.8 ± 0.1 in AA group) in hepatic tissues, and myeloperoxidase (MPO) contents (10.5 ± 0.4 & 6.6 ± 0.3 vs 20.9 ± 0.6 in AA group) in colonic tissues and (13.1 ± 0.2 & 6.3 ± 0.06 vs 23.9 ± 1.4 in AA group) in hepatic tissues at p > 0.05. Furthermore, it suppressed apoptosis by reducing expression of Caspase 3 and Bax in colonic and hepatic tissues. Therefore, molsidomine might be a promising candidate for the treatment of UC.

Dioscin prevents DSS-induced colitis in mice with enhancing intestinal barrier function and reducing colon inflammation

Dioscin is a natural steroid saponin derived from plants of the genus Dioscoreaceae. Previous studies have proved its effects of antibacterial, anti-inflammatory and hypolipidemic. In this study, our aim was to explore the protective effect and preliminary mechanism of Dioscin on dextran sulfate sodium (DSS)-induced colitis in mice. The results showed that Dioscin reduced DSS-induced disease activity index (DAI) increase, colon length shortening and colon pathological damage. In addition, Dioscin reduced excessive inflammation by reversing the cytokines levels, reducing intestinal macrophage infiltration and promoting macrophage polarization to M2 phenotype. At the same time, Dioscin maintained the intestinal barrier function by increasing the expression of zonula occludens-1 (ZO-1), occludin and mucin (Muc)-2. Moreover, Dioscin inhibited NF-κB, MAPK signaling and nucleotide oligomerization domain-like receptor family pyrin domain ontaining 3(NLRP3) inflammasome pathway in DSS-induced colitis. These results suggest that Dioscin is a competent candidate for ulcerative colitis (UC) therapy in the future.

A possible pathogenic correlation between neutrophil elastase (NE) enzyme and inflammation in the pathogenesis of coronavirus disease 2019 (COVID-19)

A growing body of evidence indicates that neutrophil elastase (NE) is involved in the pathogenesis of respiratory infectious diseases, such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This study aimed to analyze the dynamic changes in serum levels of NE associated with inflammation, disease activity, and mortality rate in patients with COVID-19. We measured the serum concentrations of NE, C-Reactive protein (CRP), interleukin (IL)- 4, IL-6, IL-8, IL-10, and vitamin D levels in 83 ICU and 69 non-ICU patients compared with 82 healthy subjects (HS) in three-time points (T1-T3). Serum levels of NE, IL-6, IL-8, and CRP in ICU and non-ICU patients were significantly higher than HS (P < 0.001) in three-time points. Also, serum levels of NE, IL-6, IL-8, and CRP in ICU patients were significantly higher than in non-ICU patients (P < 0.05). On the day of admission (T1), the levels of NE, CRP, IL-6, IL-8 were gradually decreased from T1 to T3. At the same time, IL-4 and IL-10 were gradually increased from T1 to T2 and then reduced to T3. Further analyses demonstrated that the levels of NE, IL-6, and IL-8 in deceased patients were significantly higher than in recovered patients (P < 0.05). The ROC curve analysis demonstrated that markers, including NE, IL-6, and IL-8, were valuable indicators in evaluating the activity of COVID-19. Overall, our results signify the critical role of NE in the pathogenesis of COVID-19, and also, further support that NE has a potential therapeutic target for the attenuation of COVID-19 severity.

Evodiamine Relieve LPS-Induced Mastitis by Inhibiting AKT/NF-κB p65 and MAPK Signaling Pathways

Evodiamine, an alkaloid component in the fruit of Evodia, has been shown to have biological functions such as antioxidant and anti-inflammatory. But whether evodiamine plays an improvement role on mastitis has not been studied. To investigate the effect and mechanism of evodiamine on lipopolysaccharide (LPS)-induced mastitis was the purpose of this study. In animal experiments, the mouse mastitis model was established by injecting LPS into the canals of the mammary gland. The results showed that evodiamine could significantly relieve the pathological injury of breast tissue and the production of pro-inflammatory cytokines and inhibit the activation of inflammation-related pathways such as AKT, NF-κB p65, ERK1/2, p38, and JNK. In cell experiments, the mouse mammary epithelial cells (mMECs) were incubated with evodiamine for 1 h and then stimulated with LPS. Next, pro-inflammatory mediators and inflammation-related signal pathways were detected. As expected, our results showed that evodiamine notably ameliorated the inflammatory reaction and inhibit the activation of related signaling pathways of mMECs. All the results suggested that evodiamine inhibited inflammation by inhibiting the phosphorylation of AKT, NF-κBp65, ERK1/2, p38, and JNK thus the LPS-induced mastitis was ameliorated. These findings suggest that evodiamine maybe a potential drug for mastitis because of its anti-inflammatory effects.

Effects of Selenium on MAC-T Cells in Bovine Mastitis: Transcriptome Analysis of Exosomal mRNA Interactions

Selenium, a micronutrient, is indispensable for maintaining normal metabolic functions in animals and plants. Selenium has shown promise in terms of its effect on the immune function, ability to control inflammation, and ability to improve bovine mammary gland health. Bovine mastitis remains a major threat to dairy herds globally and has economically significant impacts. The exosomes are a new mode of intercellular communication. Exosomal transfer of mRNAs, microRNAs, and proteins between cells affects the protein production of recipient cells. The development of novel high-throughput omics approaches and bioinformatics tools will help us understand the effects of selenium on immunobiology. However, the differential expression of mRNAs in bovine mammary epithelial cell-derived exosomes has rarely been studied. In the present study, differences in the exosomal transcriptome between control and selenium-treated MAC-T cells were identified by RNA sequencing and transcriptome analysis. The results of mRNA profiling revealed 1978 genes in exosomes that were differentially expressed between the selenium-treated and control cells. We selected and analyzed 91 genes that are involved in inflammation, redox reactions, and immune cell function related to mastitis. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses revealed enrichment pathways involved in selenoproteins and the Ras/PI3K/AKT, MAPK, and FOXO signaling pathways. Our results revealed that selenium may play a crucial role in immune and inflammatory regulation by influencing the differential expression of exosomal mRNAs of key genes in bovine mastitis.

New insights into crosstalk between apoptosis and necroptosis co-induced by chlorothalonil and imidacloprid in Ctenopharyngodon idellus kidney cells

Overuse and co-exposure of pesticides have become a public health problem and threat seriously water health and environmental organisms and even humans. Chlorothalonil (CT) and imidacloprid (IMI) are high-selling pesticides worldwide, which can persist in the environment, and present a series of severely toxic effects on non-target animals. However, the effect of co-application on aquatic organisms is unknown. Based on the concept of the toxic unit (TU), toxic interaction of CT and IMI was evaluated and showed the additive and synergistic toxicity on Ctenopharyngodon idellus (grass carp) kidney cell line (CIK cells). Cell death analysis found an obvious increase of the apoptosis and necrosis rates exposed to CT and IMI, and aggravation when applied together. Moreover, CT and IMI co-exposure accelerated the inhibition of CYP450s/ROS/HIF-1α signal, the decline of energy metabolism, mitochondrial dynamics disorder, activation of Bcl2/Bax/Cyt C/Casp3/Casp9 pathway and RIP1/RIP3/MLKL pathway. Bioinformatics analysis showed autophagy, cell response, NOD-like receptor signaling pathway might be affected by co-exposure. In summary, the above results indicate that co-exposure to CT and IMI has synergistic toxicity and aggravates cell death via inhibition of the CYP450s/ROS/HIF-1α signal. These data provide new insights for evaluating the stacking interaction and revealing the toxicological effects of pesticide mixture.

Transcriptional Profiling of Exosomes Derived from Staphylococcus aureus-Infected Bovine Mammary Epithelial Cell Line MAC-T by RNA-Seq Analysis

Mastitis is a common disease in the dairy industry that causes huge economic losses worldwide. Exosomes (carrying proteins, miRNA, lncRNA, etc.) play a vital role in the regulation of immune response. lncRNA can play a variety of regulatory roles by combining with protein, RNA, and DNA. The expression of mRNA and lncRNA in exosomes derived from bovine mammary epithelial cells infected by S. aureus is rarely understood. To explore this issue, RNA sequencing analysis was performed on exosomes derived from S. aureus-infected and noninfected MAC-T cells. Analysis of the sequencing results showed that there were 186 differentially expressed genes, 431 differentially expressed mRNAs and 19 differentially expressed lncRNAs in the exosomes derived from S. aureus-infected and noninfected MAC-T cells. By predicting lncRNA target genes, it was found that 19 differentially expressed lncRNAs all acted on multiple mRNAs in cis and trans. GO analysis revealed that differentially expressed genes and lncRNA target genes played significant roles in such metabolism (reactive oxygen species metabolic processes), transmembrane transport, cellular response to DNA damage stimulus, and response to cytokines. KEGG enrichment indicated that lncRNA target genes gathered in the TNF pathway, Notch pathway, MAPK pathway, NF-kappa B pathway, Hippo pathway, p53 pathway, reactive oxygen species metabolic processes, and longevity regulating pathway. In summary, all data indicated that differentially expressed gene, mRNA, and lncRNA in transcriptional profiling of exosomes participated in bacterial invasion and adhesion, oxidative stress, inflammation, and apoptosis-related signaling pathway. The data obtained in this study would provide valuable resource for understanding the lncRNA information in exosomes derived from dairy cow mammary epithelial cells and conduced to the study of S. aureus infection in dairy cow mammary glands.

Effects of Ammonia on Gut Microbiota and Growth Performance of Broiler Chickens

Simple Summary

The composition and function of gut microbiota is crucial for the health of the host and closely related to animal growth performance. Factors that impact microbiota composition can also impact its productivity. Ammonia (NH3), one of the major contaminants in poultry houses, negatively affects poultry performance. However, the influence of ammonia on broiler intestinal microflora, and whether this influence is related to growth performance, has not been reported. Our results indicated that ammonia caused changes to cecal microflora of broilers, and these changes related to growth performance. Understanding the effects of ammonia on the intestinal microflora of broilers will be beneficial in making targeted decisions to minimize the negative effects of ammonia on broilers.

Abstract

In order to investigate the influence of ammonia on broiler intestinal microflora and growth performance of broiler chickens, 288 21-day-old male Arbor Acres broilers with a similar weight were randomly divided into four groups with different NH3 levels: 0 ppm, 15 ppm, 25 ppm, and 35 ppm. The growth performance of each group was recorded and analyzed. Additionally, 16s rRNA sequencing was performed on the cecal contents of the 0 ppm group and the 35 ppm group broilers. The results showed the following: a decrease in growth performance in broilers was observed after 35 ppm ammonia exposure for 7 days and 25 ppm ammonia exposure for 14 days. At phylum level, the relative abundance of Proteobacteria phylum was increased after 35 ppm ammonia exposure. At genus level, ammonia increased the relative abundance of Escherichia–Shigella and decreased the relative abundance of Butyricicoccus, Parasutterella, Lachnospiraceae_UCG-010, Ruminococcaceae_UCG-013 and Ruminococcaceae_UCG-004. Negative correlation between Escherichia–Shigella and growth performance, and positive correlation between bacteria genera (including Butyricicoccus, Parasutterella, Lachnospiraceae_UCG-010, Ruminococcaceae_UCG-013 and Ruminococcaceae_UCG-004) and growth performance was observed. In conclusion, ammonia exposure caused changes in the structure of cecal microflora, and several species were either positively or negatively correlated with growth performance. These findings will help enhance our understanding of the possible mechanism by which ammonia affect the growth of broilers.

Hydrogen sulfide of air induces macrophage extracellular traps to aggravate inflammatory injury via the regulation of miR-15b-5p on MAPK and insulin signals in trachea of chickens

Hydrogen sulfide (H₂S) is an environmental contaminant to cause the airway damage. The release of macrophage extracellular traps (METs) is the mechanism of immune protection to harmful stimulation via microRNAs, but excessive METs cause the injury. However, few studies have attempted to interpret the mechanism of an organism injury due to H₂S via METs in chickens. Here, we investigated the transcriptome profiles, pathological morphologic changes and METs release from chicken trachea after H₂S exposure. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that 10 differentially expressed genes were related to the METs release, the MAPK and insulin signaling pathways. Morphological and immunofluorescence analysis showed that H₂S caused airway injury and MET release. H₂S activated the targeting effect of miRNA-15b-5p on activating transcription factor 2 (ATF2). Western blotting and real time quantitative PCR results showed that H₂S down-regulated the levels of dual specificity protein phosophatase1 (DUSP1) but up-regulated p38 MAP Kinase (p38) in the MAPK signal pathway. And the expression of phosphoinositide-dependent protein kinase 1 (PDK1), serine/threonine kinase (Akt), and protein kinase ζ subtypes (PKCζ) in the insulin signal pathway were increased after H₂S exposure. These promoted the release of myeloperoxidase (MPO) and degradation histone 4 (H4) to induce the release of METs. Taken together, miR-15b-5p targeted ATF2 to mediate METs release, which triggered trachea inflammatory injury via MAPK and insulin signals after H₂S exposure. These results will provide new insights into the toxicological mechanisms of H₂S and environmental ecotoxicology.

Ammonia exposure induces oxidative stress and inflammation by destroying the microtubule structures and the balance of solute carriers in the trachea of pigs

Ammonia (NH₃) is the most alkaline gaseous compound in the atmosphere and the primary gas pollutant in the piggery. It can cause irritation and damage to the airway after inhalation. However, the effects and toxicity mechanism of NH₃ on the trachea are still unclear. In order to evaluate the toxic effects of NH₃ inhalation on pig trachea, the changes of oxidative stress parameters (SOD, GSH, GSH-Px, and MDA), tissue structure and transcriptome in the trachea of pigs were examined after 30 days of exposure to NH₃. Our results showed SOD, GSH-Px and GSH in the trachea in the NH₃-treatment group were significantly decreased (P < 0.05) compared with the control group, on the contrary, MDA content was significantly higher (P < 0.05). The analysis of differentially expressed genes (DEGs) showed that 2542 DEGs (1109 up-regulated DEGs and 1433 down-regulated DEGs) were significantly changed under NH₃ exposure, including many DEGs associated with inflammation, oxidative stress, microtubule activity and SLC family, and the qRT-PCR verification results of these DEGs were consistent with the transcriptome results. The results indicated that NH₃ exposure could break down the mucosal barrier of the respiratory tract, induce oxidative stress and inflammation, reduce the activity of microtubules and disrupt the balance of SLC transporters. In this study, transcriptome analysis was used for the first time to explore the toxic mechanism of NH₃ on pig trachea, providing new insights for better assessing the toxicity mechanism of NH₃, as well as references for comparative medicine.

Se Deficiency Induced Inflammation Resulting to a Diminished Contraction of the Small Intestinal Smooth Muscle in Mice

Selenium (Se) is an essential trace element for both humans and animals. Se deficiency leads to myocardial injury, reproductive disorder, increased exudation, inflammatory injury, and other diseases. The present study analyzed the relationships of Se deficiency, inflammation, and smooth muscle contraction in the small intestine, which is the main tissue that digests and absorbs Se. The model was established by feeding the animals diets with different concentrations of Se. The results showed that the dietary Se content was positively correlated with the blood Se concentration and the intestinal Se concentration. ROS and MPO activity increased with the lack of Se. TNF-α, IL-1β, and IL-6 expression was increased at both the mRNA and protein levels with Se deficiency. The pathways tested showed that the IκBα, NF-κB p65, p38, ERK, and JNK phosphorylation levels were significantly increased with the lack of Se. Moreover, the contractility analysis confirmed that contraction of the intestinal smooth muscle was attenuated by Se deficiency, as shown by the MedLab data acquisition system. These results further illuminated the relationship between inflammation and inhibition of smooth muscle contraction under Se deficiency in the small intestine. The Ca²⁺ concentration was decreased, and RhoA phosphorylation and ROCK expression were also inhibited by Se deficiency. The results also showed that MLC protein phosphorylation decreased with Se deficiency. In conclusion, the present study indicated that inflammation under Se deficiency leads to the inhibition of smooth muscle contraction in the small intestine.

Novel insights into cytochrome P450 enzyme and solute carrier families in cadmium-induced liver injury of pigs

Cadmium (Cd) is a typical pollutant and carcinogen in environment. Exposure assessment of contaminants is an important component of occupational and environmental epidemiological studies. Early studies of Cd have focused on aquatic animals, chickens and rats. However, toxicological evaluation of Cd in pigs has not been reported. Therefore, twelve pigs were randomly divided into two groups (n = 6): the control group and the Cd group (Cd content: 15 ± 0.242 mg/kg feed) in this study, the experimental period was 30 d, and the toxic effects of Cd on the liver of weanling piglets were examined by antioxidant function, liver function, Cd content, histological examination and transcriptomics. The results showed that the changes of antioxidant function, liver function and Cd content were significant in the liver. Transcriptional profiling results showed that 399 differentially expressed genes (DEGs) were significantly up-regulated while 369 DEGs were remarkably down-regulated in Cd group, and which were concentrated in three ontologies: molecular function, cellular component and biological processes. Interestingly, significant changes in some genes of the cytochrome P450 enzyme (CYP450) and solute carrier (SLC) families have been observed and were consistent with qRT-PCR results. In conclusion, Cd could cause liver injury in weanling piglets and change the transcriptomic characteristics of liver. CYP450 and SLC families play an indispensable role in Cd-mediated hepatotoxicity. Importantly, changes in mRNA levels of CYP2B22, CYP7A1, CYP8B1, SLC26A8, SLC11A1, SLC27A2 and SLC22A7 induced by Cd have been reported for the first time. Our findings will provide a new insight for better assessing the mechanism of Cd toxicity to the liver.

Ammonia exposure causes the disruption of the solute carrier family gene network in pigs

Ammonia is the main harmful gas in livestock houses. However, the toxic mechanism of ammonia is still unclear. Therefore, we examined the effects of ammonia exposure on different tissues of fattening pigs by histological analysis and transcriptome techniques in this study. The results showed that there were varying degrees of pathological changes in liver, kidney, hypothalamus, jejunum, lungs, spleen, heart and trachea of fattening pigs under ammonia exposure. Notably, the extent of damage in liver, kidney, jejunum, lungs, hypothalamus and trachea was more severe than that in heart and spleen. Transcriptome results showed that ammonia exposure caused changes in 349, 335, 340, 229, 120, 578, 407 and 115 differentially expressed genes in liver, kidney, spleen, lung, trachea, hypothalamus, jejunum and heart, respectively. Interestingly, the changes in solute vector (SLC) family genes were found in all 8 tissues, and the verified gene results (SLC11A1, SLC17A7, SLC17A6, SLC6A4, SLC22A7, SLC25A3, SLC28A3, SLC7A2, SLC6A6, SLC38A5, SLC22A12, SLC34A1, SLC26A1, SLC26A6, SLC27A5, SLC22A8 and SLC44A4) were consistent with qRT-PCR results. In conclusion, ammonia exposure can cause pathological changes in many tissues and organs of fattening pigs and changes in the SCL family gene network. Importantly, the SCL family is involved in the toxic mechanism of ammonia. Our findings will provide a new insight for better assessing the mechanism of ammonia toxicity.

Resveratrol relieves chlorothalonil-induced apoptosis and necroptosis through miR-15a/Bcl2-A20 axis in fish kidney cells

Chlorothalonil (CT) is a commonly used fungicide and its excessive application seriously threatens aquatic life and human health. Resveratrol (RSV) is a natural polyphenol and can be used as a therapeutic and preventive agent for the treatment of various diseases. To explore the toxic mechanism of CT exposure on fish kidney cell, as well as the alleviation effect of RSV, we established CT poisoning and/or RSV treatment fish kidney cell models. Ctenopharyngodon idellus kidney (CIK) cell line was treated with CT (5 μg/L) and/or RSV (10 μM) for 48 h. The results showed that CT exposure activated cytochromeP450s (CYPs) including CYP1A1, CYP1B1 and CYP1C, caused malondialdehyde (MDA) accumulation, inhibited glutathione (GSH) levels and glutathione peroxidase (GPX) activities, increased the expression of miR-15a and downregulated BCL2 and TNFα-induced protein 3 (TNFAIP3, A20), triggered mitochondrial pathway mediated apoptosis and receptor interacting serine/threonine kinase (RIP)-dependent necroptosis in CIK cells. However, cell death under CT exposure could be relieved by RSV treatment through inhibiting the expression of CYP1 family genes and restoring miR-15a/BCL2-A20 axis disorders. Overall, we conclude that RSV could relieve CT-induced apoptosis and necroptosis through miR-15a/Bcl2-A20 axis in CIK cells. These results enrich the toxicological mechanisms of the CT and confirm that RSV can be used as a potential antidote for CT poisoning.

Pb exposure triggers MAPK-dependent inflammation by activating oxidative stress and miRNA-155 expression in carp head kidney

Lead (Pb) is a toxic heavy metal and an aquatic pollutant. Various amounts of heavy metals are released into the environment through industrial discharge, causing excessive contamination of aquatic ecosystems. The head kidney is a unique immune organ of the bony fish and plays an important role in the metabolism of heavy metals. Studies of toxic Pb exposure that have investigated the head kidney of carp are limited. This study was carried out to explore the potential immunotoxicity effects of Pb and the specific related mechanisms in the carp head kidney. Pb poisoning was shown to induce the production of reactive oxygen species (ROS) and increase the expression levels of phosphorylated proteins related to the MAPK pathway, including p38, extracellular signal-regulated protein kinase (ERK), and c-Jun N-terminal kinase (JNK). We also found that microRNA-155 played a key role in regulating the production of inflammatory factors TNF-α, IL-1β, and IL-6, and the pre-miRNA-155 inhibitor reversed the Pb-induced inflammation. In conclusion, these in vitro and in vivo findings suggest that oxidative stress and the MAPKs are involved in the Pb-induced inflammasome response, and the production of microRNA-155 aggravated the occurrence of inflammation in carp head kidney.

Alpinetin prevents inflammatory responses in OVA-induced allergic asthma through modulating PI3K/AKT/NF-κB and HO-1 signaling pathways in mice

Allergic asthma is the most common type of asthma which characterized by inflammatory responses of the airways. Alpinetin, a flavonoid compound derived from the ginger family of medicinal herbs, possesses various biological properties including anti-inflammatory, anti-oxidant and other medical effects. In this study, we aimed to evaluate the effects of alpinetin on OVA-induced allergic asthma, and further to examine its molecular mechanisms underlying these processes in vivo and in vitro. Mice were sensitized and challenged with OVA to build allergic asthma model in vivo. Bronchoalveolar lavage fluid (BALF) was collected for inflammatory cells analysis and lung tissues were examined for histopathological examination. The levels of IL-5, IL-13, IL-4, IgE, TNF-α, IL-6 and IL-1β were determined by the respective ELISA kits. The PI3K/AKT/NF-κB and HO-1 signaling pathways were examined by western blot analysis. The results showed that alpinetin significantly ameliorated OVA-induced pathologic changes of lungs, such as decreasing massive inflammatory cell infiltration and mucus hypersecretion, and reduced the number of inflammatory cells in BALF. Alpinetin also decreased the OVA-induced levels of IL-4, IL-5, IL-13 and IgE. Furthermore, alpinetin inhibited OVA-induced phosphorylation of p65, IκB, PI3K and AKT, and the activity of HO-1 in vivo. More importantly, these anti-inflammatory effects and molecular mechanisms of alpinetin has also been confirmed in LPS-stimulated RAW 264.7 macrophages in vitro. In conclusion, above results indicate that alpinetin exhibites a potent anti-inflammatory activity in allergic asthma through modulating PI3K/AKT/NF-κB and HO-1 signaling pathways, which would be used as a promising therapy agent for allergic asthma.

Cl-amidine attenuates lipopolysaccharide-induced mouse mastitis by inhibiting NF-κB, MAPK, NLRP3 signaling pathway and neutrophils extracellular traps release

Cl-amidine, a peptidylarginine deiminase inhibitor, has been shown to ameliorate the disease course and clinical manifestation in variety of disease models. Due to the beneficial effects of Cl-amidine, it has been becoming the hottest compound for the study in inflammatory diseases. However, the anti-inflammatory activity of Cl-amidine in lipopolysaccharide (LPS)-induced mouse mastitis remains unclear. In this study, we investigated the effects of Cl-amidine on LPS-induced mastitis mouse model. The mouse mastitis model was established by injection of LPS through the canals of the mammary gland. Cl-amidine was administered intraperitoneally 1 h before LPS treatment. The results showed that Cl-amidine significantly attenuated the damage of the mammary gland, which suppressed the activity of myeloperoxidase (MPO). The real-time PCR results indicated that Cl-amidine inhibited the production of TNF-α, IL-1β and IL-6 in LPS-induced mouse mastitis. Moreover, the western blot results indicated that Cl-amidine decreased the phosphorylation of IκB, p65, p38, ERK and the expression of NLRP3 in LPS-induced mouse mastitis. Furthermore, the neutrophils extracellular traps (NETs) were determined by Quant-iT picogreen dsDNA assay kit®, which suggested that Cl-amidine significantly inhibited the NETs in mouse serum. This study demonstrated that Cl-amidine decreased the pathological injury in LPS-induced mouse mastitis by inhibiting NF-κB, MAPK, NLRP3 signaling pathway and NETs release, which provides a potential candidate for the treatment of mastitis.