Atmospheric H2S triggers immune damage by activating the TLR-7/MyD88/NF-κB pathway and NLRP3 inflammasome in broiler thymus

Inflammasome/NF-κB translocation inhibition via PPARγ agonist mitigates inorganic mercury induced nephrotoxicity

Mercury (Hg) pollution poses global human health and environmental risks. However, still knowledge gaps exist on both exposures and health effects. Here, we combined transcriptome sequencing technique to further investigate the specific mechanisms of inorganic Hg toxicity in the kidney. Strikingly, transcriptomic analysis revealed that 4174 unigenes (including 2646 upregulated and 1528 downregulated unigenes) were differentially expressed under acute HgCl₂ (5 mg/kg) exposure in the kidney. Additionally, we observed that HgCl₂ selectively induced tumor necrosis factor superfamily (TNFSF) to participate in renal damage, which was consistent with the high-throughput sequencing data. The phenomenon is accompanied by NLRP3 inflammasome and NF-κB signal activation in the kidney. Simultaneously, ELISA results shown that TNF-α, IL-1β and IL-6 concentrations in the kidney were significant increased. KEGG enrichment analysis showed that peroxisome proliferators-activated receptors (PPAR) signaling pathway might be vital toxic mechanism of Hg in the kidney. Then, our data showed that PPARγ agonist (GW 1929) attenuated HgCl₂ (15 μg/ml)-induced apoptosis and NLRP3 inflammasome activation via decreasing translocation of NF-κB and increasing Bcl2 levels in vitro. Along with this, we demonstrated that PPARγ antagonists (GW9662) effectively aggravated HgCl₂-induced nephrotoxicity. Overall, our results suggested that PPARγ signaling pathway is considered to be a protective mechanism to combat against HgCl₂-triggered NLRP3 inflammasome activation and apoptosis.

Selenium relieves oxidative stress, inflammation, and apoptosis within spleen of chicken exposed to mercuric chloride

Mercuric chloride (HgCl₂) is a widely distributed environmental pollutant with multiorgan toxicity including immune organs such as spleen. Selenium (Se) is an essential trace element in animal nutrition and exerts biological activity to antagonize organ toxicity caused by heavy metals. The objective of this study was to explore the underlying mechanism of the protective effects of Se against spleen damage caused by HgCl₂ in chicken. Ninety male Hyline brown chicken were randomly divided into 3 groups namely Cont, HgCl₂, and HgCl₂+Se group. Chicken were provided with the standard diet and nontreated water, standard diet and HgCl₂-treated water (250 ppm), and sodium selenite-treated diet (10 ppm) plus HgCl₂-treated water (250 ppm), respectively. After being fed for 7 wk, the spleen tissues were collected, and spleen index, the microstructure of the spleen, and the indicators of oxidative stress, inflammation, apoptosis as well as heat shock proteins (HSP) were detected. First, the results of spleen index and pathological examination confirmed that Se exerted an antagonistic effect on the spleen injury induced by HgCl₂. Second, Se ameliorated HgCl₂-induced oxidative stress by decreasing the level of malondialdehyde and increasing the levels of glutathione, glutathione peroxidase, and total antioxidant capacity. Third, Se attenuated HgCl₂-induced inflammation by decreasing the protein expression of nuclear factor kappa-B, inducible nitric oxide synthase, and cyclooxygenase-2, and the gene expression of interleukin (IL)-1β, IL-6, IL-8, IL-12β, IL-18 as well as tumor necrosis factor-α. Fourth, Se inhibited HgCl₂-induced apoptosis by downregulating the protein expression of BCL2 antagonist/killer 1 and upregulating the protein expression of B-cell lymphoma-2. Finally, Se reversed HgCl₂-triggered activation of HSP 60, 70, and 90. In conclusion, Se antagonized HgCl₂-induced spleen damage in chicken, partially through the regulation of oxidative stress, inflammatory, and apoptotic signaling.

The involvement of miR-6615-5p/Smad7 axis and immune imbalance in ammonia-caused inflammatory injury via NF-κB pathway in broiler kidneys

Ammonia (NH₃), a toxic gas, has deleterious effects on chicken health in intensive poultry houses. MicroRNA can mediate inflammation. The complex molecular mechanisms underlying NH₃ inhalation-caused inflammation in animal kidneys are still unknown. To explore the mechanisms, a broiler model of NH₃ exposure was established. Kidney samples were collected on day 14, 28, and 42, and meat yield was evaluated on day 42. We performed histopathological examination, detected miR-6615-5p and mothers against decapentaplegic homolog 7 (Smad7), and determined inflammatory factors and cytokines in kidneys. The results showed that excess NH₃ reduced breast weight and thigh weight, which indicated that excess NH₃ impaired meat yield of broilers. Besides, kidney tissues displayed histopathological changes after NH₃ exposure. Meanwhile, the increases of inducible nitric oxide synthase (iNOS) activity and nitric oxide content were obtained. The mRNA and protein expression of inflammatory factors, including nuclear factor-κB (NF-κB), cyclooxygenase-2, prostaglandin E synthases, and iNOS increased, indicating that NF-κB pathway was activated. T-helper (Th) 1 and regulatory T (Treg) cytokines were downregulated, whereas Th2 and Th17 cytokines were upregulated, suggesting the occurrence of Th1/Th2 and Treg/Th17 imbalances. In addition, we found that Smad7 was a target gene of miR-6615-5p in chickens. After NH₃ exposure, miR-6615-5p expression was elevated, and Smad7 mRNA and protein expression were reduced. In summary, our results suggest that NH₃ exposure negatively affected meat yield; and miR-6615/Smad7 axis and immune imbalance participated in NH₃-induced inflammatory injury via the NF-κB pathway in broiler kidneys. This study is helpful to understand the mechanism of NH₃-induced kidney injury and is meaningful to poultry health and breed aquatics.

Hydrogen Sulfide Plays an Important Role by Influencing NLRP3 inflammasome

Inflammasome is a complex composed of several proteins and an important part of the natural immune system. Nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) inflammasome is composed of NLRP3, apoptosis associated speck like protein (ASC) and pro-caspase-1. It plays an important role in many diseases. Hydrogen sulfide (H₂S) is an important signaling molecule that regulates many physiological and pathological processes. Recent studies indicated that H₂S played anti-inflammatory and pro-inflammatory roles in many diseases through influencing NLRP3 inflammasome, but its mechanism was not fully understood. This article reviewed the progress about the effects of H₂S on NLRP3 inflammasome and its mechanisms involved in recent years to provide theoretical basis for in-depth study.

Hydrogen sulfide: An endogenous regulator of the immune system

Hydrogen sulfide (H₂S) is now recognized as an endogenous signaling gasotransmitter in mammals. It is produced by mammalian cells and tissues by various enzymes - predominantly cystathionine β-synthase (CBS), cystathionine γ-lyase (CSE) and 3-mercaptopyruvate sulfurtransferase (3-MST) - but part of the H₂S is produced by the intestinal microbiota (colonic H₂S-producing bacteria). Here we summarize the available information on the production and functional role of H₂S in the various cell types typically associated with innate immunity (neutrophils, macrophages, dendritic cells, natural killer cells, mast cells, basophils, eosinophils) and adaptive immunity (T and B lymphocytes) under normal conditions and as it relates to the development of various inflammatory and immune diseases. Special attention is paid to the physiological and the pathophysiological aspects of the oral cavity and the colon, where the immune cells and the parenchymal cells are exposed to a special "H₂S environment" due to bacterial H₂S production. H₂S has many cellular and molecular targets. Immune cells are "surrounded" by a "cloud" of H₂S, as a result of endogenous H₂S production and exogenous production from the surrounding parenchymal cells, which, in turn, importantly regulates their viability and function. Downregulation of endogenous H₂S producing enzymes in various diseases, or genetic defects in H₂S biosynthetic enzyme systems either lead to the development of spontaneous autoimmune disease or accelerate the onset and worsen the severity of various immune-mediated diseases (e.g. autoimmune rheumatoid arthritis or asthma). Low, regulated amounts of H₂S, when therapeutically delivered by small molecule donors, improve the function of various immune cells, and protect them against dysfunction induced by various noxious stimuli (e.g. reactive oxygen species or oxidized LDL). These effects of H₂S contribute to the maintenance of immune functions, can stimulate antimicrobial defenses and can exert anti-inflammatory therapeutic effects in various diseases.

Ammonia-triggered apoptosis via immune function and metabolic process in the thymuses of chickens by proteomics analysis

Ammonia (NH₃), an environmental pollutant with a pungent odor, is not only an important volatile in fertilizer production and ranching, but also main basic component of haze. In present study, we found that ultrastructural changes and 3167 differentially expressed proteins (DEPs) using proteomics analysis in the thymuses of chickens exposed to NH₃ on day 42. Obtained DEPs were enriched using GO and KEGG; and 66 DEPs took part in immune function, metabolic process, and apoptosis in the thymuses of chickens treated with NH₃. 9 genes of DEPs were validated using qRT-PCR, and mRNA expression of 2 immune-related genes (CTSG and NFATC2), 3 metabolic process-related genes (APOA1, GOT1, and GOLGA3), and 4 apoptosis-related genes (PIK3CD, CTSS, CAMP, and NSD2) were consistent with DEPs in chicken thymuses. Our results indicated that excess NH₃ led to immunosuppression, metabolic disorder, and apoptosis in chicken thymuses. Present study gives a novel insight into the mechanism of NH₃ toxicity and demonstrated that immune response, metabolism process, and apoptosis were important in the mechanism of NH₃ toxicity of chicken exposure to high concentration of NH₃.

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

Ammonia (NH₃) is an environmental contaminant that is causing increasing problems with human and animal health due to the development of poultry industry. There are limited studies on the effect of NH₃ inhalation toxicity on the intestinal tract of animals, and underlying molecular mechanisms remain unclear. In the present study, we established a chicken model of NH₃ aspiration-induced injury for 42 days and observed histopathological changes of the jejunum. Tandem mass tag-based quantitative proteomic analysis was applied to investigate changes in the protein profile in the jejunum tissue of chickens that were exposed to NH₃. Overall, 48 significantly differentially expressed proteins (DEPs) were identified. GO and KEGG analyses revealed that most DEPs were closely related to epithelial-to-mesenchymal transition (EMT), cell-cell junctions, and fibrosis-related factors. Regarding fibrosis, type I collagen and fibronectin were significantly increased. With respect to EMT, epithelial marker proteins (such as E-cadherin and keratin) were repressed, while mesenchymal marker proteins (such as vimentin) were activated. Loss of epithelial cell-cell junctions (such as tight junctions, adherens junctions and desmosomes) were observed. Additionally, overexpression of transforming growth factor-beta (TGF-β) may play a key role in the EMT process and fibrosis. Taken together, these findings suggested that NH₃ triggered the EMT and disassembly of epithelial cell-cell contacts, resulting in jejunal fibrosis that was mediated by TGF-β in chickens. The results of our study will contribute to provide a technical reference regarding the research methods of intestinal toxicity of NH₃ and have largely regulatory implications for ecological risk assessment of human health.

Bisphenol A regulates cytochrome P450 1B1 through miR-27b-3p and induces carp lymphocyte oxidative stress leading to apoptosis

Bisphenol A (BPA) is an industrial raw material widely used in water bottles, medical devices and food packaging, and is now ubiquitous in the environment. However, the effects of BPA on the toxicity of fish lymphocytes and the roles of microRNA (miRNA) in this process remain poorly understood. To explore the mechanism, we exposed carp spleen lymphocytes to BPA of 1, 5 and 10 nM for 24 h. The results showed that BPA induced carp lymphocyte apoptosis. BPA inhibited the expression of miR-27b-3p mRNA, thereby increasing the expression of cytochrome P450 1B1, increasing ROS levels, inhibiting SOD, CAT, GSH-PX activity, GSH content, promoting the accumulation of NOS and MDA. At the same time, BPA activated the mitochondrial apoptosis pathway, inhibited the expression of BCL-2, and promoted the expression of CytC, BAX, Caspase-9 and Caspase-3. Dual luciferase reporter system showed CYP1B1 is the target genes of miR-27b-3p and negatively regulated by it. Overexpression of miR-27b-3p partially reversed oxidative stress and apoptosis of carp spleen lymphocytes induced by BPA stimulation. Taken together, BPA exposure can target up regulate CYP1B1 expression by down regulating miR-27b-3p expression, thus causing oxidative stress and inducing apoptosis of carp spleen lymphocytes through mitochondrial pathway. Our study will provide theoretical basis for immunotoxicology mechanism research and environmental protection of BPA in fish.

Assessment of ionic homeostasis imbalance and cytochrome P450 system disturbance in mice during fumonisin B1 (FB1) exposure

Fumonisin B1 (FB1) is a mycotoxin frequently found in agricultural commodities, and poses a considerable risk for human and animal health. The aim of this study was to investigate the toxic effect of FB1 in mice intestine. Male Kunming mice (n = 40) were treated with FB1 diet for 42 days. Histopathological and biochemical analyses, including ion concentrations, transcription of ATPase subunits and mRNA expression of cytochrome P450s (CYP450s) analyses were performed on duodenum, cecum and colon of mice. The results revealed that FB1 caused histological alterations, including partial shedding of villous epithelial cells and inflammatory cell infiltration. Furthermore, a significant change in Na⁺, K⁺ and Ca²⁺ in serum, and the mRNA expression of ATPase subunits and CYP450s in intestinal tracts were observed in FB1-exposed mice. Our results suggested that FB1 exposure induce histopathological injury via disrupting CYP isoforms transcription and triggering ion homeostasis imbalance in mice intestinal tracts.

Selenium Deficiency Induces Inflammation via the iNOS/NF-κB Pathway in the Brain of Pigs

Selenium (Se) is an essential trace element to maintain homeostasis in humans and animals. The aim of the present study was to clarify the mechanism of Se deficiency-induced inflammation in the pig's brain. Twenty-four healthy pigs were randomly divided into two groups (n = 12/group): control group (group C) was fed diet with 0.3 mg/kg inorganic Se, and Se-deficient group (group L) was fed diet with 0.007 mg/kg inorganic Se. At the 90th day of the experiment, the histology in the pig's brain was observed by the microscope, the NO levels and iNOS activity were assayed, and the mRNA and protein expression levels of inflammatory cytokines (iNOS, COX-2, NF-κB, and PTGEs) and HSPs (HSP27, HSP40, HSP60, HSP70, and HSP90) were detected by real-time quantitative PCR and Western blot. Compared with group C, both of NO levels and iNOS activity were increased in group L, and the mRNA and protein expression levels of inflammatory cytokines (iNOS, COX-2, NF-κB, and PTGEs) and HSPs (HSP27, HSP40, HSP60, HSP70, and HSP90) were also upregulated; histological observation displayed inflammatory response in the brain of pig. In summary, diet with Se deficiency can activate the iNOS/NF-κB pathway to upregulate the expression of inflammatory cytokines, thereby leading to inflammatory lesions in the pig's brain, and HSPs are involved in the compensatory regulation of inflammation. This study provides a reference for the prevention of pig brain inflammation from the perspective of nutrition.

Anti-inflammatory effect of selenium on lead-induced testicular inflammation by inhibiting NLRP3 inflammasome activation in chickens

Lead (Pb) is a deleterious environmental pollutant that is toxic to testes. Selenium (Se) possesses antioxidant and anti-inflammatory properties. Nucleotide-binding domain, leucine-rich-containing family, pyrin-domain containing-3 (NLRP3) inflammasome is involved in inflammatory response. However, the function of NLRP3 inflammasome in antagonistic effect of Se on inflammation caused by Pb remains unknown. The purpose of this research is to identify anti-inflammatory role of Se on testicular toxicity induced by Pb with an emphasis on oxidative stress, inflammation and NLRP3 signaling pathway in chicken. In present study, sixty seven-day-old Hyline male chickens were assigned into four groups. The feeding program consisted of a commercial diet (0.49 mg/kg Se), a Se-supplemented diet (1 mg/kg Se), a Pb-supplemented diet (0.49 mg/kg Se and 350 mg/kg Pb) and a Se-supplemented and Pb-supplemented diet (1 mg/kg Se and 350 mg/kg Pb), respectively. On the 12th week, blood was collected to measure serum testosterone level and testicular tissues were removed to determine Se and Pb concentrations, testicular function, histological structure, oxidative stress indicators and inflammation-related factors (Nuclear factor-kappaB, tumor necrosis factor-α, cyclooxygenase-2, NLRP3, apoptosis-associated speck-like protein containing a caspase recruitment domain, caspase-1, interluekin (IL)-1β, IL-6, IL-18 and interferon-γ). The experimental results showed that after Pb administration, testicular injury was confirmed via histological assessment; testicular dysfunction were further indicated by decreased testosterone level and mRNA expression of steroidogenic acute regulatory protein, cytochrome P450 side-chain cleavage, 3β-hydroxysteroid dehydrogenase and 17β-hydroxysteroid dehydrogenase. Moreover, NLRP3 signaling pathway activated by Pb-caused oxidative stress was up-regulated accompanied by promotion in reactive oxygen species, nitric oxide, inducible nitric oxide synthase and malondialdehyde and reduction in antioxidants including glutathione peroxidase and glutathione s-transferase. Se administration ameliorated testicular tissue injury, testicular function, oxidative stress and inflammation. In conclusion, Se exhibited antagonistic role in Pb-induced testicular injury via enhancing antioxidant system and inhibiting inflammation in chickens.

Selenium deficiency induced necroptosis, Th1/Th2 imbalance, and inflammatory responses in swine ileum

Selenium (Se) deficiency has a significant impact on the swine breeding industry by inducing digestive system damage and diarrhea. However, the molecular mechanism remains unclear. Our objectives were to investigate if different amounts of necroptosis, inflammatory responses, and T helper cell 1/T helper cell 2 (Th1/Th2) imbalances were induced by Se deficiency in intestinal porcine jejunal epithelial cells (IPEC-J2) and swine ileum tissue. Therefore, Se-deficient models were successfully established both in vitro and in vivo. In the current study, the cell morphological observation results showed that Se deficiency seriously affected the growth and differentiation of IPEC-J2 cells. Moreover, the necroptosis staining and histomorphology observation results showed that the number of necroptotic cells increased significantly, and the ileal tissue exhibited abnormal structures, including necroptotic features and inflammatory cell infiltration, in the Se-deficient group. Furthermore, Se deficiency resulted in accelerated cell necroptosis by increasing (p < .05) the expression of genes related to the tumor necrosis factor-α pathway at both the protein and messenger RNA (mRNA) levels compared to the control group. Moreover, the relative mRNA and protein expression of the inflammatory genes and their responses to dietary Se deficiency were consistent with the resultant Th1/Th2 imbalances in vitro and in vivo. Taken together, the results suggested that Se deficiency caused necroptosis, inflammatory responses, and abnormal expression of cytokines in swine ileum tissue. These findings might help us to explain the damage induced by Se deficiency to the digestive system of swine.

Ameliorative Effect of Selenomethionine on Cadmium-Induced Hepatocyte Apoptosis via Regulating PI3K/AKT Pathway in Chickens

Selenium (Se) is a trace element for human and animal health. Cadmium (Cd) is a known human carcinogen. The effects of Cd on the environment and humans are well known. Because chickens are at the top of the food chain, it is a good experimental animal model for assessing heavy metal toxicity and its potential threat to humans. Selenomethionine (Se-met) is a suitable form for nutritional Se supplementation. Therefore, the toxicity of Cd to the chicken liver and the antagonistic effects of Se-met on Cd were examined at the molecular level in the present study. The results showed that oxidative stress indicators (apoptosis-related genes, P13K/AKT pathway-related genes, and heat shock proteins (HSPs)-related genes) in the Cd group have changed significantly, indicating Cd induced hepatocyte stress and apoptosis. Interestingly, the changes in oxidative stress indicators (apoptosis-related genes, P13K/AKT pathway-related genes, and HSPs-related genes) in the Cd-Se-met group were mitigated compared with the control group. Our results indicated that Cd can induce hepatocyte apoptosis and stress in the chickens. Se-met has an ameliorative effect on Cd-induced apoptosis of chicken hepatocyte by regulating PI3K/AKT pathway. Our findings will provide a new insight for better understanding of the detoxification function of Se-met to heavy metals.

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

Cadmium (Cd) is a well-known environmental pollutant and can damage fish. MicroRNAs (miRNAs) can involve in inflammation and immunosuppression. However, the mechanisms of miRNAs are still unclear in common carp (Cyprinus carpio L.) treated by Cd. In current study, 54 juvenile common carp were randomly divided into the control group and the Cd group (0.26 mg L^-1 Cd) and were cultured for 30 days. The results revealed inflammatory damage in the spleens of common carp after Cd exposure using morphological construction. There were 23 differentially expressed miRNAs including 17 up-regulated differentially expressed miRNAs (miR-1-4-3p, miR-7-1-5p, miR-7-2-5p, miR-10-43-5p, miR-34-3-5p, miR-128-4-3p, miR-128-5-3p, miR-132-2-5p, miR-132-6-5p, miR-216-3-5p, miR-216-4-5p, miR-375-2-3p, miR-375-4-3p, miR-375-5-3p, miR-375-7-3p, miR-375-8-3p, and miR-724-5p) and 6 down-regulated differentially expressed miRNAs (miR-9-6-5p, miR-25-9-3p, miR-31-3-5p, miR-31-12-5p, miR-103-5-5p, and miR-122-1-3p). The 23 miRNAs regulated 2022 target mRNAs. There were 10 pathways and 9 annotation clusters on 2022 target mRNAs using KEGG and GO analysis, respectively. Among them, 5 pathways (NF-κB signaling pathway, Jak-STAT signaling pathway, MAPK signaling pathway, Th1 and Th2 cell differentiation, and Toll-like receptor signaling pathway) and 7 GO terms (negative regulation of immune system process, T cell mediated immunity, regulation of immune response, inflammatory response, positive regulation of inflammatory response, regulation of inflammatory response, and inflammasome complex) were associated with inflammatory response and immunosuppression. miR-375-4-3p, NF-κB, COX-2, PTGES, and IL-4/13A increased and miR-31-12-5p, miR-9-6-5p, MMP9, IL-11, SPI1, and T-Bet decreased using transcriptome sequencing and RT-qPCR in Cd-treated common carp spleens, which revealed that our results were reliable. Our data indicated that miRNAs mediated inflammation-immunosuppressive injury caused by Cd in common carp spleens using whole transcriptome-based miRNA-mRNA network analysis. Our study provided new insights into the toxicology of Cd exposure.

Hydrogen sulfide upregulates miR-16-5p targeting PiK3R1 and RAF1 to inhibit neutrophil extracellular trap formation in chickens

Hydrogen sulfide (H₂S) is a toxic air pollutant that causes immune damage. Recent studies have found that neutrophil extracellular trap (NET) formation is one way in which neutrophils exert immune functions. In addition, the formation of NETs is also related to thrombosis and autoimmune diseases. Recent studies have shown that miRNAs are involved in the regulation of a variety of pathophysiological processes. Here, we investigated the role of H₂S in regulating the formation of NETs by affecting miR-16-5p. Our study established an in vitro H₂S exposure model for neutrophils using phorbol-myristate-acetate (PMA) to induce NET formation. We observed the morphological changes of cells with scanning electron microscopy and fluorescence microscopy. Then, the content of extracellular DNA and the expression of MPO and NE in each group were detected. The results showed that H₂S inhibited the formation of NETs. The expression of miR-16-5p and its target genes PiK3R1 and RAF1 was then measured by qRT-PCR. H₂S upregulated miR-16-5p and inhibited expression of the target genes PiK3R1 and RAF1, and it subsequently inhibited the Pi3K/AKT and ERK pathways and decreased respiratory burst levels. Furthermore, H₂S attenuated inositol 1,4,5-trisphosphate receptor (IP3R)-mediated endoplasmic reticulum calcium outflow as well as autophagy caused by PMA. This study enriches H₂S immunotoxicity research and provides a possible solution for the treatment of NET-related diseases.

Antagonistic effect of selenium on lead-induced neutrophil apoptosis in chickens via miR-16-5p targeting of PiK3R1 and IGF1R

Environmental contamination by heavy metals, such as lead (Pb), can lead to severe immune dysfunction. MicroRNAs (miRNAs) are involved in regulating immunity. Whether Pb can regulate neutrophil apoptosis through miRNA, and whether selenium (Se) can antagonize this response are still unknown. We treated neutrophils with 12.5 μM (CH₃OO)₂Pb and 1 μM Na₂SeO₃ for 3 h, after which apoptosis was evaluated using acrideine orange/ethidium bromide (AO/EB) dual fluorescent staining and flow cytometry. The results showed that neutrophil apoptosis was significantly increased following Pb exposure, and that this response was prevented upon Se addition. Pb up-regulates miR-16-5p and leads to the subsequent down-regulation of the target genes phosphoinositide-3-kinase regulatory subunit 1 (PiK3R1), insulin-like growth factor 1 receptor (IGF1R), and phosphatidylinositol 3 kinase (Pi3K)-protein kinase B (AKT), followed by activation of the tumor protein P53 (P53)-B-cell lymphoma-2 (Bcl-2)/Bcl-2-Associated X protein (Bax)-cytochrome c (Cytc)-Caspase 9 (mitochondrial apoptotic pathway) and the tumor necrosis factor receptor superfamily member 6 (Fas)-Fas-associated death domain protein (Fadd)-Caspase 8 (death receptor pathway). Pb also triggered oxidative stress and indirectly activated the mitochondrial apoptotic pathway. We conclude that miR-16-5p plays a key role in the apoptosis of neutrophils exposed to Pb by down-regulating the expression of PiK3R1 and IGFR1, thereby activating the mitochondrial apoptotic pathway and death receptor pathway. Se can prevent Pb-induced apoptosis.

Mycoplasma gallisepticum Infection Impaired the Structural Integrity and Immune Function of Bursa of Fabricius in Chicken: Implication of Oxidative Stress and Apoptosis

Mycoplasma gallisepticum (MG) induces a dysregulated immune response in the lungs and air ways of poultry. However, the mechanism of MG-induced immune dysregulation is still not completely understood. In the present study, the effect of MG-infection on chicken bursa of fabricius (BOF) is investigated. Histopathology, electron microscopy, TUNEL assay, qRT-PCR and western blot were employed to examine the hallmarks of oxidative stress and apoptosis. The data revealed that MG-infection induced oxidative stress and decreased antioxidant responses in BOF tissues compared to control group. Histopathological study showed pathological changes including reduction in lymphocytes and increased inflammatory cell infiltration in MG-infection group. Ultrastructural assessment represents obvious signs of apoptosis such as mitochondrial swelling, shrinkage of nuclear membrane and fragmentation of nucleus. Increased cytokine activities were observed in MG-infection group compared to control group. Meanwhile, the mRNA and protein expression level of apoptosis-related genes were significantly (p < 0.05) upregulated in MG-infection group. Terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) assay further confirmed that MG induced apoptosis in BOF tissues as TUNEL-stained positive nuclei were remarkably increased in MG-infection group. In addition, MG-infection significantly reduced the number of CD8⁺ lymphocytes in chicken BOF at day 7. Moreover, bacterial load significantly increased at day 3 and day 7 in MG-infection group compared to control group. These results suggested that MG-infection impaired the structural integrity, induced oxidative stress and apoptosis in chicken BOF tissues, which could be the possible causes of damage to immune function in chicken BOF.

Mycoplasma gallisepticum triggers immune damage in the chicken thymus by activating the TLR-2/MyD88/NF-κB signaling pathway and NLRP3 inflammasome

Previous studies reported that Mycoplasma gallisepticum (MG) causes immune dysregulation in chickens. However, the underlying mechanisms of immune dysregulation in chickens are still unclear. The thymus is a primary lymphoid organ where the proliferation, differentiation and selection of T-lymphocytes occur, whereas T-lymphocytes play a crucial role in innate immune responses. To evaluate the effects of MG-infection on chicken thymus, White Leghorn chickens were divided into (1) control group and (2) MG-infection group. ATPase activities were detected by commercial kits. The hallmarks of inflammation, autophagy and energy metabolism were examined in chicken thymus tissues by histopathology, transmission electron microscopy, immunofluorescence microscopy, RT-PCR and western blotting. Immunofluorescence examination revealed that the number of CD8⁺ lymphocytes has significantly reduced in MG-infection group. In addition, morphological analysis revealed that MG induced inflammatory cells infiltration. The mitochondria were swollen and chromatin material was condensed in MG-infection group. The mRNA and protein expression results showed that MG-infection triggered the nucleotide-binding oligomerization domain, leucine rich repeat and pyrin domain containing 3 (NLRP3) inflammasome through TLR-2/MyD88/NF-κB signaling pathway. Meanwhile, the expressions of autophagy-related genes were reduced both at mRNA and protein level in MG-infection group. While, ATPase activities and the expression of energy metabolism-related genes were reduced in the thymus of MG-infected chickens. These results showed that MG-infection triggered inflammatory response through TLR-2/MyD88/NF-κB signaling pathway, activated NLRP3 inflammasome, reduced the level of autophagy and impaired energy metabolism, which then lead to tissue damage in chicken thymus. The data provide new insights in MG-infection-mediated immune damage and provide possible therapeutic targets for future targeted therapy.

Ammonia inhalation-induced inflammation and structural impairment in the bursa of fabricius and thymus of broilers through NF-κB signaling pathway

Ammonia (NH₃) is a toxic, environmental pollutant, and irritant gas. Previous studies reported the toxic effects of NH₃ which led to inflammation in various organs of chicken. However, the exact mechanism of NH₃-induced inflammation in chicken lymphoid organs bursa of fabricius (BF) and thymus is still elusive. Thus, this study was designed to investigate NH₃-induced inflammation in chicken BF and thymus. Experimental chickens were divided into low (5.0 mg/m³), middle (10.0-15.0 mg/m³), and high (20.0-45.0 mg/m³) NH₃-treated groups. To investigate NH₃-induced inflammation in chicken's BF and thymus, histological observation, NO content and iNOS activity, inflammatory cytokine contents, and mRNA levels were performed by light microscopy, microplate spectrophotometer, ELISA assay, and qRT-PCR. The finding of the present study showed that NH₃ exposure reduced BF and thymus index, increased nitric oxide (NO) content and inducible nitric oxide synthase (iNOS) activity, inflammatory cytokine contents and mRNA levels of nuclear factor-kappa B (NF-κB), cyclooxygenase-2 (Cox-2), tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6), IL-10, IL-1β, IL-18, toll-like receptor 2A (TLR-2A), and iNOS. Histopathological examination revealed signs of inflammation including increased nuclear debris and vacuoles in the cortex and medulla of thymus and bursal follicles. Conclusively, our findings displayed that NH₃ exposure affects the normal function of BF and thymus and led inflammation. The data provided a new ground for NH₃-induced toxicity and risk assessment in chicken production.

Toll-like receptors (TLRs) respond to tributyltin chloride (TBT-Cl) exposure in the river pufferfish (Takifugu obscurus): Evidences for its toxic injury function

Tributyltin chloride (TBT-Cl) residual in water body had become a noticeable ecological problem for aquatic ecosystems. Toll-like receptors (TLRs) are an ancient family of pattern recognition receptors that play key roles in detecting nonself antigens and immune system activation. In this study, we explored the effect of TBT-Cl exposure on four TLRs expression in river pufferfish, Takifugu obscurus. The four T. obscurus Toll-like receptors (To-TLRs) contained different types of domains such as leucine-rich repeats (LRRs), leucine-rich repeats, typical subfamily (LRR_TYP) and other special domains. The To-TLRs mRNA transcripts expressed in all tissues, also To-TLR2 was investigated with higher level in kidney, as well as To-TLR3 in kidney, while To-TLR18 in liver and To-TLR22 in intestine. After the acute and chronic exposure of TBT-Cl, To-TLR2 and To-TLR3 mRNA transcripts were significantly down-regulated in gill. However, To-TLR18 and To-TLR22 were significantly up-regulated in gill and liver. Moreover, the histology and immunohistochemistry (IHC) results showed the different injury degrees of TBT-Cl in liver and gill and implied the cytoplasm reorganization after TBT-Cl stress and the function of immunoregulation for To-TLRs to TBT-Cl exposure. All the results indicated that To-TLRs might involve in sensing and mediating innate immune responses caused by TBT-Cl for keeping detoxification homeostasis.

Ammonia regulates chicken tracheal cell necroptosis via the LncRNA-107053293/MiR-148a-3p/FAF1 axis

Ammonia (NH₃) is a known harmful gas that causes injury to the respiratory system. Ammonia also exists in haze, forming secondary organic aerosols. However, the specific damage caused by NH₃ in chicken trachea has not been determined. The regulatory mechanism of ceRNA and its multiple roles have been proposed in many pathomechanisms; therefore, we investigated the functional role of ceRNA in chicken trachea after NH₃ inhalation. Broiler chicken trachea exposed to NH₃ was selected as the research object. The pathological ultrastructure was observed by transmission electron microscopy. Transcriptome analyses were applied and referenced, and lncRNA-107053293 and miR-148a-3p and FAF1 were selected. A dual-luciferase reporter assay verified the target relationship. Real-time quantitative PCR (RT-PCR) and western blotting were performed to examine the expression levels of necroptosis genes, such as RIPK1, RIPK3, MLKL, caspase 8, and FADD. Our results indicated that lncRNA-107053293 regulated necroptosis by acting as a competing endogenous RNA of miR-148a-3p. FAF1, as a gene target of miR-148a-3p, also affects necroptosis.

Selenium deficiency exacerbates LPS-induced necroptosis by regulating miR-16-5p targeting PI3K in chicken tracheal tissue

Multiple tissue necrosis is one of the morphological features of selenium deficiency-mediated injury. MicroRNA (miRNA) participates in the occurrence and development of necroptosis by regulating target genes. Necroptosis is a programmed form of necrosis, and it is closely related to lipopolysaccharide (LPS)-induced injury. Our aim was to investigate whether Se deficiency can promote tracheal injury caused by LPS through miRNA-induced necroptosis. By establishing models of tracheal injury in Se-deficient chickens, we verified the targeting relationship between chicken-derived miR-16-5p and PI3K through bioinformatics, qRT-PCR and WB analyses, and we measured the changes in the expression of genes related to the PI3K/AKT pathway, RIP3/MLKL pathway and MAPK pathway and of heat shock proteins. Under the condition of Se deficiency, the following results were observed: PI3K/AKT expression decreased with the upregulation of miR-16-5p, the expression of necroptosis-related factors (TNF-α, RIP1, FADD, RIP3 and MLKL) increased, and the expression of Caspase 8 significantly decreased (p < 0.05). Light microscopy observations indicated that cell necrosis was the main pathological change due to Se deficiency injury in the tracheal epithelium. The MAPK pathway was activated, and HSP expression was upregulated, indicating that the MAPK pathway and HSPs are both involved in Se deficiency-mediated necroptosis. In addition, Se deficiency promoted the expression of necroptosis-related genes in LPS-treated chickens (p < 0.05), and the pathological changes of cell necrosis were more obvious. In conclusion, we demonstrated that Se deficiency regulates the miR-16-5p-PI3K/AKT pathway and exacerbates LPS-induced necroptosis in chicken tracheal epithelial cells by activating necroptosis-related genes.

Astilbin protects chicken peripheral blood lymphocytes from cadmium-induced necroptosis via oxidative stress and the PI3K/Akt pathway

Astilbin (ASB), a dihydroflavonol glycoside, is widely found in a variety of plants and in functional foods and acts as a powerful antioxidant. The aim of this study was to investigate the underlying mechanisms involved in the antagonistic effects of ASB on cadmium (Cd)-induced necroptosis in chicken peripheral blood lymphocytes. Peripheral blood lymphocytes were aseptically collected from Roman white hens and then randomly divided into five groups: the control group was incubated without additional reagents, while the other groups were incubated with Cd, ASB, a combination of Cd and ASB, and 0.1% DMSO. After a 24 h treatment, cell samples were collected. The results showed that some morphological changes consistent with necroptosis were observed in the Cd-treated groups, suggesting the occurrence of necroptosis. Simultaneously, antioxidant activity markers (CAT, SOD, GSH, GSH-px, and T-AOC) decreased and indicators of oxidative stress (MDA, iNOS, NO, H₂O₂, ·OH and ROS) increased. The production of ROS induced the activation of the PI3K/Akt signaling pathway, as the expression levels of PI3K, Akt and PDK1 were significantly elevated. Additionally, the expression levels of RIPK3, RIPK1, MLKL, TAK1, TAB2 and TAB3 were increased and that of Caspase-8 was decreased, which could cause the necroptosis. However, the most important our results was that ASB supplements remarkably attenuated the Cd-induced effects. We conclude that the Cd treatment promoted an imbalance of the antioxidant status and activated the PI3K/Akt pathway, leading to necroptosis in chicken peripheral blood lymphocytes, and that ASB was able to partially ameliorate the effect of Cd-induced necroptosis.

Molybdenum and cadmium co-induce oxidative stress and apoptosis through mitochondria-mediated pathway in duck renal tubular epithelial cells

High doses of molybdenum (Mo) and cadmium (Cd) cause adverse reactions on animals, but the joint toxic effects of Mo and Cd on duck renal tubular epithelial cells are not fully illustrated. To investigate the combined effects of Mo and Cd on oxidative stress and mitochondrial apoptosis in primary duck renal tubular epithelial cells, the cells were either treated with (NH₄)₆Mo₇O₂₄·4H₂O (480, 960 μM Mo), 3CdSO₄·8H₂O (2.5, 5.0 μM Cd) or combination of Mo and Cd for 12 h, and then the joint cytotoxicity was evaluated. The results demonstrated that Mo or/and Cd exposure could induce release of intracellular lactate dehydrogenase, reactive oxygen species generation, acidification, increase levels of malondialdehyde and [Ca²⁺]i, decrease levels of glutathione, glutathione peroxidase, catalase, superoxide dismutase, total antioxidant capacity, Na⁺/K⁺-ATPase, Ca²⁺-ATPase, and mitochondrial membrane potential; upregulate mRNA levels of Caspase-3, Bak-1, Bax, and cytochrome C, inhibit Bcl-2 mRNA level, and induce cell apoptosis in a dose-dependent manner. Furthermore, the changes of these indicators in co-treated groups were more remarkable. The results indicated that exposure to Mo or/and Cd could induce oxidative stress and apoptosis via the mitochondrial pathway in duck renal tubular epithelial cells and the two metals may have a synergistic effect.

Ellagic Acid Activated PPAR Signaling Pathway to Protect Ileums Against Castor Oil-Induced Diarrhea in Mice: Application of Transcriptome Analysis in Drug Screening

Background

Acute diarrhea is still a common and serious disease. The causes of acute diarrhea are very complicated. Therefore, we need to find a medicine to control diarrhea symptoms, save time for diagnosis of pathogens, and prevent drug abuse. Ellagic acid (EA), a natural polyphenol drug, has anti-diarrhea effects. However, the action mechanisms of EA for non-specific diarrhea have not been characterized.

Materials and Methods

To study the mechanisms of EA, mice were divided into four groups. Group C were intraperitoneally injected with 0.1 ml physiological saline and orally given 0.2 ml physiological saline, and then after experiment began 0.5 h, orally administered 0.3 ml physiological saline. Group D were intraperitoneally injected with 0.1 ml physiological saline and orally given 0.2 ml castor oil, and then after experiment began 0.5 h, orally administered 0.3 ml physiological saline. Group E were intraperitoneally injected with 0.1 ml physiological saline and orally given 0.2 ml castor oil, and then after experiment began 0.5 h, orally administered 0.3 ml EA (10 mg/ml). Group V were intraperitoneally injected with 0.1ml GW9662 (1m g/ml) and orally given 0.2 ml castor oil, and then after experiment began 0.5 h, orally administered 0.3 ml EA (10 mg/ml). Transcriptome were performed on ileum tissues of mice in group D and E. Histological examination and qRT-PCR were performed on ileum tissues of mice in group C, D, E, and V.

Results

We found that a total of 273 differentially expressed genes (DEGs) were obtained, including 160 up-regulated DEGs and 113 down-regulated DEGs. The DEGs were enriched in 458 Gene Ontology (GO) terms and 15 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, respectively. The peroxisome proliferator activated receptor (PPAR) signaling pathway was the most significantly enriched in KEGG pathways. We used the PPAR-specific antagonist GW9662 to validate the anti-diarrhea and anti-inflammatory effect of EA in group V compared with group E. Conclusively, EA protected ileums against castor oil-induced inflammation and diarrhea by activating the PPAR signaling pathway and a method was used to study the mechanism of EA.

Excessive Cu2+ deteriorates arsenite-induced apoptosis in chicken brain and resulting in immunosuppression, not in homeostasis

Trace elements such as copper (Cu) and arsenic (As) are two of the major contaminants and well-known inducers of cognitive deficits and neurobehavioral changes. This study evaluated the immunotoxicity of their individual or combined exposure on different brain regions in chickens. Consequently, nuclear damage and organelle lesions, especially mitochondria were observed under Cu or/and As stress, in which positive regulation of key proteins, dynamin-related protein 1 (Drp1), Cytochrome C (Cyt c), BCL2-associated X (Bax), Caspases 3 and P53 was detected by qRCR and Western blot analyses, indicating disturbed mitochondrial dynamic equilibrium and apoptosis execution. In addition, qRCR analysis confirmed the involvement of cytokines secreted by different populations of helper T cells, indicative of cellular immunity. Gene expression studies showed marked up regulation of Th1/Th17 cytokines along with heat shock protein (HSP) 70, a synergism was noted in co-administration group. Interesting, lower apoptosis index was noted in brainstem compared to cerebrum and cerebellum. An intense immunosuppression and heat shock response against Cu or/and As was also seen in cerebrum and cerebellum but not in brainstem. In conclusion, our study suggests a synergistic neurotoxicity in chickens under Cu and As exposure. These findings provide a basic understanding of mitochondrial abnormality-initiated neuropathology in response to environmental pollutant mixtures, suggesting an adaptive response to the frangibility of the central nerve system.

Selenium alleviates lipopolysaccharide-induced endometritisviaregulating the recruitment of TLR4 into lipid rafts in mice

Selenium (Se) is an essential trace element for living organisms and plays diverse biological roles.

Application of transcriptome analysis: Oxidative stress, inflammation and microtubule activity disorder caused by ammonia exposure may be the primary factors of intestinal microvilli deficiency in chicken

Ammonia (NH₃), an inhaled harmful gas, is not only an important volatile in fertilizer production and ranching, but also the main basic component of haze. However, the effect and mechanism of NH₃ on the intestines are still unclear. To investigate the intestinal toxicity of NH₃ inhalation, morphological changes, transcriptome profiles and oxidative stress indicators of jejunum in broiler chicken exposed to NH₃ for 42 days were examined. Results of morphological observation showed that NH₃ exposure caused deficiency of jejunal microvilli and neutrophil infiltration. Transcriptomics sequencing identified 677 differential expressed genes (DEGs) including 358 up-regulated genes and 319 down-regulated genes. Enrichment analysis of obtained DEGs by Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) found that biological functions and pathways affected by NH₃ included antioxidant function, inflammation, microtubule and nutrition transport. Relative genes validation and chemical detection confirmed that NH₃-induced oxidative stress by activating CYPs and inhibiting antioxidant enzymes promoted inflammatory response and decreased microtubule activity, thus destroying the balance of nutritional transporters. Our study perfects the injurious mechanism of NH₃ exposure and provides a new insight and method for environmental risk assessment.

Taxifolin ameliorates DEHP-induced cardiomyocyte hypertrophy via attenuating mitochondrial dysfunction and glycometabolism disorder in chicken

Di-(2-ethylhexyl) phthalate (DEHP) is a prevalent environmental contaminant that severely impacts the health of human and animals. Taxifolin (TAX), a plant flavonoid isolated from yew, exerts protective effects on cardiac diseases. Nevertheless, whether DEHP could induce cardiomyocyte hypertrophy and its mechanism remains unclear. This study aimed to highlight the specific molecular mechanisms of DEHP-induced cardiomyocyte hypertrophy and the protective potential of TAX against it. Chicken primary cardiomyocytes were treated with DEHP (500 μM) and/or TAX (0.5 μM) for 24 h. The levels of glucose and adenosine triphosphate (ATP) were detected, and cardiac hypertrophy-related genes were validated by real-time quantitative PCR (qRT-PCR) and Western blot (WB) in vitro. The results showed that DEHP-induced cardiac hypertrophy was ameliorated by TAX, as indicated by the increased cardiomyocyte area and expression of atrial natriuretic peptide (ANP), natriuretic peptides A-like (BNP) and β-myosin heavy cardiac muscle (β-MHC). Furthermore, DEHP induced cardiac hypertrophy via the interleukin 6 (IL-6)/Janus kinase (JAK)/signal transducer and activator of transcription 3 (STAT3) pathway in vitro. In addition, DEHP disrupted mitochondrial function and glycometabolism by activating the insulin-like growth factor 1 (IGF1)/phosphatidylinositol 3-kinase (PI3K) pathway and the peroxisome proliferator activated receptors (PPARs)/PPARG coactivator 1 alpha (PGC-1α) pathway to induce cardiac hypertrophy in vitro. Intriguingly, those DEHP-induced changes were obviously alleviated by TAX treatment. Taken together, cardiac hypertrophy was induced by DEHP via activating the IL-6/JAK/STAT3 signaling pathway, triggering glycometabolism disorder and mitochondrial dysfunction in vitro, can be ameliorated by TAX. Our findings may provide a feasible molecular mechanism for the treatment of cardiomyocyte hypertrophy induced by DEHP.

Hydrogen sulfide-induced oxidative stress leads to excessive mitochondrial fission to activate apoptosis in broiler myocardia

Hydrogen sulfide (H₂S), as an environmental gas pollutant, has harmful effects on many tissues and organs, including myocardium. However, the underlying mechanisms of H2S-induced myocardia toxicity remain poorly understood. The present study was designed to investigate the effect of H₂S on myocardia injury in broilers from the perspective of apoptosis. 30 ppm H2S was administered in the broiler chamber for 2, 4 and 6 week, respectively, and the myocardial samples in control groups and H2S groups were collected immediately after euthanized broilers. Transmission electron microscope, test kits, qRT-PCR and western blot were performed. Results showed that H₂S exposure decreased the activities of catalase (CAT) and total antioxidant capability (T-AOC), whereas the content of hydrogen peroxide (H₂O₂) and the activity of inducible nitric oxide synthase (iNOS) enhanced. Besides, we found the excessive expression of mitochondrial fission genes (Drp1 and Mff) by H₂S, the dynamic balance of mitochondrial fission and fusion is destroyed. Furthermore, the levels of pro-apoptotic gene (including CytC, Cas3, Cas8, Cas9, TNF-α and Bax) increased after H₂S exposure, as well as the expression level of anti-apoptotic gene bcl-2 decreased. At the same time, the activities of ATPase (including Na⁺-K⁺-ATPase, Ca²⁺-ATPase, Mg²⁺-ATPase and Ca²⁺-Mg²⁺-ATPase) weakened under H₂S exposure. Therefore, we conclude that H₂S induced oxidative stress and then leaded to excessive mitochondrial fission, which involved in apoptosis and damage broiler myocardia.

Role of c-Myc/chloride intracellular channel 4 pathway in lipopolysaccharide-induced neurodegenerative diseases

LPS-induced neuronal apoptosis leads to neurodegenerative diseases (NDs). However, the mechanisms underlying NDs pathogenesis remains unclear. The apoptotic response to activation of the c-Myc/chloride intracellular channel (CLIC4) pathway is directed through a mitochondrial pathway. In this study, we aimed to explore the c-Myc/CLIC4 pathway in the progression of NDs induced by lipopolysaccharide (LPS). In an in vivo experiment, the results of HE staining, transmission electron microscopic, immunofluorescence microscopy of cleaved caspase-3 and Bax and the increasing expression of apoptotic pathway related proteins in mitochondria showed that LPS (10 mg/kg) administration damaged mitochondrial and induced hippocampal neuron apoptosis. The Western blot and RT-PCR indicated that LPS induced the activation of c-Myc/CLIC4 pathway. Furthermore, in an in vitro experiment, PC12 cells were exposed to LPS to induce cell injuries to mimic the model of NDs. To further confirm the role of the c-Myc/CLIC4 pathway in LPS-induced neuronal apoptosis, the gene knockout of c-Myc and CLIC4 were performed by CRISPR/Cas9. The results of the flow cytometry assay and Annexin V-FITC/PI showed that knocking out c-Myc and CLIC4 significantly reduced cell apoptosis. The results of Western blot and dual immunofluorescence with Cyt c and TOM20 showed that knocking out c-Myc and CLIC4 significantly reduced the expression of mitochondrial apoptosis-related proteins. Our data confirmed that LPS-induced apoptosis is regulated by the activation of c-Myc/CLIC4 pathway. These results support further research mechanisms underlying neurodegenerative diseases and can provide effective pharmacodynamic targets for the clinical development of therapeutic drugs for neurodegenerative diseases.

Role of miR-731 and miR-2188-3p in mediating chlorpyrifos induced head kidney injury in common carp via targeting TLR and apoptosis pathways

Chlorpyrifos (CPF) is an environmental pollutant with increasing importance due to its high toxicity to fish and aquatic animals. In the present study, we divided 120 common carp (Cyprinus carpio L.) into two groups including control group and CPF group, CPF group was exposed to 14.5 μg/L CPF for 30 d. 17 miRNAs were differentially expressed in CPF group head kidney tissues according to the results of miRNAome analysis. In addition, histopathological examination and electron microscopy proved that CPF exposure could lead to damage of head kidney and obvious apoptosis characteristics. The possible target genes of miRNA were predicted using online target gene prediction websites, miRNAome sequencing, GO and KEGG enrichment. miRNAome results showed that expression of miR-731 and miR-2188-3p in CPF group was 0.48 time and 0.45 time as control group, respectively. qRT-PCR results proved the reality of miRNAome. During CPF exposure, mRNA expression of TLR pathway genes and its downstream genes involved in autophagy and apoptosis pathway including TLR1, TLR2, TLR7, TLR9, MyD88, IRAK1, IRAK4, IRF7, PI3K, AKT, mTOR, Caspase3, Caspase8 and Bax were differentially increased under CPF exposure, along with ATG13 and Bcl2 decreased at the same time. Western blot results indicated that apoptosis related protein Caspase3 and Caspase8 were differentially up-regulated in the CPF group. In summary, CPF exposure could induce apoptosis while inhibited autophagy in head kidney of common carp via the regulation of miR-2188-3p and miR-731 by targeting TLR pathway. These results provide new insights for unveiling the biological effects of CPF and miRNAs in common carp.